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Nitric oxide is generated from nitric oxide synthase following hyperglycemia-induced oxidative stress during the course of diabetes mellitus (DM). We examined the temporal immuno-expression of neuronal nitric oxide synthase (nNOS) in the pancreas of diabetic and non-diabetic rats using immunohistochemical, immunofluorescence and western blot techniques 12 h, 24 h, 1 week, 2 weeks, 1, 8 and 15 months after induction of DM. nNOS co-localized with pancreatic beta cells but disappears 12 h after the onset of DM. In contrast, the nNOS content of pancreatic nerves increased significantly (p < 0.001) 24 h after the induction of DM, and decreased sharply thereafter. However, nNOS-positive ganglion cells were observed even 15 months post-diabetes. ROS increased by more than 100% two months after the onset of DM compared to non-diabetic control but was significantly (p < 0.000001) reduced at 9 months after the induction of DM. The pancreatic content of GSH increased significantly (p < 0.02) after 9 months of DM. Although, TBARS content was significantly (p < 0.009; p < 0.002) lower in aged (9 months) non-diabetic and DM rats, TBARS rate was markedly (p < 0.02) higher 9 months after the induction of DM when compared to younger age group. In conclusion, nNOS is present in pancreatic beta cell, but disappears 12 h after the onset of diabetes. In contrast, the tissue level of nNOS of pancreatic nerves increased in the first week of diabetes, followed by a sharp reduction. nNOS may play important roles in the metabolism of pancreatic beta cell. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) is recognized as one of the leading causes of morbidity and mortality in the world. About 5–6% of the world population suffers from this disease and the number of people diagnosed with diabetes is rapidly increasing. Diabetes has been demonstrated to be associated with oxidative stress and hyperglycemia, one of the most important indictors of oxidative stress. The endogenous mechanisms of enzymes and antioxidants are able to destroy the reactive species and create a balance between antioxidant and free radicals. In diabetes, the oxidative stress is increased because of the deficiency in the antioxidant defense. The intake of antioxidants, such as vitamin C, may reduce the oxidative stress associated with diabetes and hence help to restore the antioxidant defense system. The aim of this article was to investigate the effect of different doses of vitamin C on the biochemical parameters of normal and streptozotocin (STZ)-induced diabetic rats. Biochemical analysis was used to study the effect of this vitamin on the biochemical parameters of normal and diabetic rats. Liver and kidney enzymes were elevated after the onset of diabetes. Moderate doses of vitamin C significantly ( P < 0.0008) reduced plasma gamma-glutamyl level in diabetic rats. Moreover, vitamin C significantly ( P < 0.01) reduced the blood urea nitrogen level of diabetic rats. The plasma level of electrolytes, such as calcium and sodium, also changed significantly ( P < 0.00001) after oral administration of vitamin C. Antioxidants, such as vitamin C, may ameliorate the biochemical parameters of diabetic rats. [ABSTRACT FROM AUTHOR]

Skeletal muscle atrophy and neuropathy are two of the major long-term complications of diabetes mellitus (DM). This article investigates the effect of streptozotocin (STZ)-induced type 1 DM on contraction and cation contents in soleus and EDL muscles compared to age-matched control rats. Adult Wistar rats were humanely killed and the soleus and EDL muscles located and excised rapidly and placed in organ baths. The muscles were electrically stimulated (EFS, 50 V, 1 ms, 1–50 Hz) and isometric contraction monitored using a chart recorder. At the end of the experiments the muscles were blotted, weighed, and dissolved in concentrated nitric acid for the measurements of cation contents. Diabetic rats have significantly ( P < 0.05) reduced body and muscle weights and significantly ( P < 0.05) elevated blood glucose (29.65 ± 0.33 mM, n= 10) compared to control (6.06 ± 0.21 mM, n= 10). EFS evoked frequency dependent contraction in both soleus and EDL muscles of healthy control rats. The response was significantly ( P < 0.05, n= 8) increased in EDL compared to soleus. In the diabetic soleus and EDL muscles the force of contraction was significantly ( P < 0.05, n= 8) reduced in both muscle types compared to control. The levels of total sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), zinc (Zn2+), copper (Cu2+), and iron (Fe2+) were significantly ( P < 0.05) reduced in diabetic soleus and EDL muscles compared to control. The results indicate that STZ-induced skeletal muscle atrophy is associated with marked reductions in both the force of contraction and cation contents in EDL and soleus muscles of the rat. [ABSTRACT FROM AUTHOR]

This study investigated the effect of streptozotocin (STZ)-induced type 1 diabetes mellitus (DM) on total protein concentration and levels of sodium (Na+), potassium (K+), magnesium (Mg2+), zinc (Zn2+), copper (Cu2+), calcium (Ca2+), and iron (Fe2+) in the pancreas, parotid, submandibular, and lacrimal glands of the rat, compared to age-matched control animals. Protein concentrations were measured by the Bradford Assay, whereas levels of Na+, K+, Mg2+, Zn2+, Cu2+, Ca2+, and Fe2+ were measured by flame photometry and atomic absorbance spectrophotometry. The results show marked changes in the characteristics of diabetic and control animals. Diabetic rats and their different glands weighed significantly ( P < 0.05) less compared to age-matched controls. Diabetic rats also have significantly elevated blood glucose and significantly reduced plasma insulin, compared to controls. The results also show that the concentrations of proteins and levels of cations were significantly ( P < 0.05) reduced in the pancreas, parotid, submandibular and lacrimal glands of diabetic rats, compared to glands from age-matched animals. These differences in the cation contents and protein levels in STZ-induced DM in this study, along with supporting evidences from previous studies, may provide evidence for the development of long-term complications of DM including exocrine gland deficiencies. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) shows a markedly increased incidence of cardiovascular pathology that leads to hypertension, endothelial macro- and microangiopathy, diabetic nephropathy, and myocardial infarction. Atrial natriuretic peptide (ANP), is a 28 amino acid peptide hormone synthesized mainly by the heart atria and ventricles. It has potent diuretic and natriuretic properties. In this article the effect of long-term DM on blood plasma, kidney, and heart atrial and ventricular ANP concentrations were evaluated in streptozotocin (STZ)-induced 8-month diabetic and control rats by using radioimmunoassay (RIA). Moreover, ANP receptors in STZ-induced, 8-month diabetic rat kidneys were studied by receptor autoradiography. In addition, the expression of ANP concentrations in the kidney of diabetic and control rats was evaluated by means of immunohistochemistry. Body weight loss and increased blood glucose levels were used as indices of DM in the STZ-induced diabetic rats. Our results showed significantly higher ANP concentrations in diabetic plasma ( P < 0.05), kidney ( P < 0.01), heart atria ( P < 0.05), and ventricles ( P < 0.01) compared to controls. We also demonstrated a significant decrease in ANP receptors in the outer cortex ( P < 0.05), juxtaglomerular medulla ( P < 0.05), and papilla ( P < 0.05) of 8-month diabetic rat kidneys compared to controls. The observed increase in ANP levels in plasma and kidney could play a role in the development of diabetic nephropathy: probably by reducing the levels of ANP receptors in diabetic kidney. Furthermore, the role of ANP in the STZ-induced diabetic heart merits additional study. [ABSTRACT FROM AUTHOR]

Vitamin E has the ability to scavenge a wide spectrum of free radicals, including singlet oxygen, superoxide, and hydroxyl radicals. It has beneficial effects against several other disorders, such as atherosclerosis and ischemic heart disease, because it acts as a transcriptional regulator for gene expression via a transcription factor TAP. The beneficial effect of vitamin E on plasma insulin and glucagon levels was examined using radioimmunoassay technique. Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin at a dose of 60 mg/kg body weight. Vitamin E was given at a dose of either 0.2 mg, 0.4 mg, or 0.8 mg per animal 10 days before and after the onset of diabetes. Vitamin E significantly ( P < 0.05) increased plasma insulin levels in normal rats but failed to increase the plasma insulin level in diabetic rats. In contrast, vitamin E caused a significant ( P < 0.05) reduction in plasma glucagon level in rats treated before and after the onset of diabetes. Vitamin E may ameliorate some diabetic complication via reduction in the level of circulating glucagon. [ABSTRACT FROM AUTHOR]

Diabetes is associated with hyperglycemia, one of the most important causes of oxidative stress. Endogenous antioxidants are able to destroy the reactive species and create a balance between antioxidant and free radicals. In diabetes, the oxidative stress is increased due to the deficiency in the antioxidant defense. The intake of antioxidants, such as vitamin E, may reduce the oxidative stress associated with diabetes and hence help to restore the antioxidant defense system. The aim of this article was to investigate the effect of different doses of vitamin E on the biochemical parameters of normal and streptozotocin (STZ)-induced diabetic rats. Biochemical analysis was used to study the effect of this vitamin on the biochemical parameters of normal and diabetic rats. The plasma levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactic dehydrogenase (LDH), and gamma-glutamyl transferase (γ-GT) were significantly increased after the onset of diabetes. In addition, STZ-induced diabetes also caused an increase in the level of blood urea nitrogen (BUN) and creatinine. Oral administration of vitamin E (0.2–0.4 mg daily) significantly ( P < 0.05) decreased the plasma level of ALT, AST, and γ-GT. In addition, there was a slight but not significant reduction in the plasma level of ALP. Parameters of kidney function, such as BUN and creatinine, were slightly reduced after the oral administration of vitamin E. The plasma level of electrolytes, such as calcium and sodium, also changed significantly ( P < 0.00001) after the oral administration of vitamin E. Vitamin E ameliorates the metabolic and biochemical parameters of diabetic rats. [ABSTRACT FROM AUTHOR]

Histamine H3 receptors (H3Rs) are involved in several neuropsychiatric diseases including epilepsy. Therefore, the effects of H3R antagonist E177 (5 and 10 mg/kg, intraperitoneal (i.p.)) were evaluated on acute pentylenetetrazole (PTZ)-induced memory impairments, oxidative stress levels (glutathione (GSH), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD)), various brain neurotransmitters (histamine (HA), acetylcholine (ACh), γ-aminobutyric acid (GABA)), and glutamate (Glu), acetylcholine esterase (AChE) activity, and c-fos protein expression in rats. E177 (5 and 10 mg/kg, i.p.) significantly prolonged step-through latency (STL) time in single-trial passive avoidance paradigm (STPAP), and shortened transfer latency time (TLT) in elevated plus maze paradigm (EPMP) (all P < 0.05). Moreover, and in the hippocampus of PTZ-treated animals, E177 mitigated abnormal levels of AChE activity, ACh and HA (all P < 0.05), but failed to modify brain levels of GABA and Glu. Furthermore, E177 alleviated hippocampal oxidative stress by significantly decreasing the elevated levels of MDA, and increasing the abnormally decreased level of GSH (all P < 0.05). Furthermore, E177 reduced elevated levels of hippocampal c-fos protein expression in hippocampal tissues of PTZ-treated animals (all P < 0.05). The observed results propose the potential of H3R antagonist E177 with an added advantage of avoiding cognitive impairment, emphasizing the H3Rs as a prospective target for future pharmacological management of epilepsy with associated memory impairments. [ABSTRACT FROM AUTHOR]

The downregulation of cannabinoid type-2 receptors (CB2R) have been reported in numerous diseases including cardiovascular diseases (CVDs). The activation of CB2R has recently emerged as an important therapeutic target to mitigate myocardial injury. We examined whether CB2R activation can protect against isoproterenol (ISO)-induced myocardial injury (MI) in rats. In the present study, we investigated the cardioprotective effect of β-caryophyllene (BCP), a naturally occurring dietary cannabinoid in rat model of MI. Rats were pre- and co-treated with BCP (50 mg/kg, orally) twice daily for 10 days along with subcutaneous injection of ISO (85 mg/kg) at an interval of 24 h for two days (9th and 10th days). AM630 (1 mg/kg), a CB2 receptor antagonist, was injected intraperitoneal as a pharmacological challenge prior to BCP treatment to reveal CB2R-mediated cardioprotective mechanisms of BCP. Desensitization of beta-adrenergic receptor (β-AR) signaling, receptor phosphorylation and recruitment of adapter β-arrestins were observed in ISO-induced MI in rats. ISO injections caused impaired cardiac function, elevated the levels of serum cardiac marker enzymes, and enhanced oxidative stress markers along with altered PI3K/Akt and NrF2/Keap1/HO-1 signaling pathways. ISO also promoted lysosomal dysfunction along with activation of NLRP3 inflammasomes and TLR4-NFκB/MAPK signaling and triggered rise in proinflammatory cytokines. There was a concomitant mitochondrial dysfunction followed by the activation of endoplasmic reticulum (ER) stress-mediated Hippo signaling and intrinsic pathway of apoptosis as well as altered autophagic flux/mTOR signaling in ISO-induced MI. Furthermore, ISO also triggered dyslipidemia evidenced by altered lipids, lipoproteins and lipid marker enzymes along with ionic homeostasis malfunction. However, treatment with BCP resulted in significant protective effects on all biochemical and molecular parameters analyzed. The cardioprotective effects were further strengthened by preservation of cardiomyocytes and cell organelles as observed in histopathological and ultrastructural studies. Interestingly, treatment with AM630, a CB2R antagonist was observed to abrogate the protective effects of BCP on the biochemical and molecular parameters except hyperlipidemia and ionic homeostasis in ISO-induced MI in rats. The present study findings demonstrate that BCP possess the potential to protect myocardium against ISO-induced MI in a CB2-dependent and independent manner. [Display omitted] • CB2 activation by BCP resensitize and restored ISO-stimulated dysregulation of beta AR signaling. • BCP attenuates GRK2 upregulation and β2AR phosphorylation mediated arrestin recruitment via CB2 activation. • BCP prevents ISO induced biochemical alterations and the related signaling cascades in a CB2 dependent manner. • However, BCP prevents ionic homeostasis alterations and hyperlipidemia in a CB2 independent manner. [ABSTRACT FROM AUTHOR]

The global prevalence of waterpipe tobacco smoking is increasing. Although the cardiorespiratory, renal, and reproductive effects of waterpipe smoking (WPS) are well-documented, there is limited knowledge regarding its adverse impact on the liver. Therefore, our study aimed to assess the effects and potential mechanisms of WPS inhalation for one or four weeks on the liver. Mice were exposed to WPS for 30 min per day, five days per week, while control mice were exposed to clean air. Analysis using light microscopy revealed the infiltration of immune cells (neutrophils and lymphocytes) accompanied by vacuolar hepatic degeneration upon WPS inhalation. At the four-week timepoint, electron microscopy analysis demonstrated an increased number of mitochondria with a concomitant pinching-off of hepatocyte plasma membranes. WPS exposure led to a significant rise in the activities of liver enzymes alanine aminotransferase and aspartate aminotransferase in the bloodstream. Additionally, WPS inhalation elevated lipid peroxidation and reactive oxygen species levels and disrupted the levels of the antioxidant glutathione in liver tissue homogenates. The concentration of proinflammatory cytokines, including tumor necrosis factor α, interleukin (IL)-6, and IL-1β, was significantly increased in the WPS-exposed group. Furthermore, WPS inhalation induced DNA damage and a significant increase in the levels of cleaved caspase-3, cytochrome C and hypoxia-inducible factor 1α along with alterations in the activity of mitochondrial complexes I, II, III and IV. Our findings provide evidence that WPS inhalation triggers changes in liver morphology, oxidative stress, inflammation, DNA damage, apoptosis, and alterations in mitochondrial activity. [ABSTRACT FROM AUTHOR]

T2DM is linked to an increase in the fracture rate as compared to the nondiabetic population even with normal or raised bone mineral density (BMD). Hence, bone quality plays an important role in the pathogenesis of skeletal fragility due to T2DM. This study analyzed the changes in the trabecular bone microstructure due to T2DM at various time points in ovariectomized and nonovariectomized rats. Animals were divided into four groups: (I) control (sham), (II) diabetic (sham), (III) ovariectomized, and (IV) ovariectomized with diabetes. The trabecular microarchitecture of the femoral head was characterized using a micro-CT. The differences between the groups were analyzed at 8, 10, and 14 weeks of the onset of T2DM using a two-way analysis of variance and by post hoc multiple comparisons. The diabetic group with and without ovariectomies demonstrated a significant increase in trabecular separation and a decrease in bone volume fraction, trabecular number, and thickness. BMD decreased in ovariectomized diabetic animals at 14 weeks of the onset of T2DM. No significant change was found in connectivity density and degree of anisotropy among groups. The structural model index suggested a change towards a weaker rod-like microstructure in diabetic animals. The data obtained suggested that T2DM affects the trabecular structure within a rat's femoral heads negatively and changes are most significant at a longer duration of T2DM, increasing the risk to hip fractures. [ABSTRACT FROM AUTHOR]

Cisplatin (CP) is a potent and widely used chemotherapeutic agent. However, the clinical benefits of CP are compromised because it elicits nephrotoxicity and ototoxicity. In this study, we investigated the nephroprotective effects of the phytochemical genipin (GP) isolated from the gardenia ( Gardenia jasminoides ) fruit, using a murine model of CP-induced nephropathy. GP pretreatment attenuated the CP-induced renal tissue injury by diminishing the serum blood urea nitrogen, creatinine, and cystatin C levels, as well as those of kidney injury molecule-1. In addition, GP attenuated the CP-induced oxidative/nitrative stress by suppressing the activation of NADPH oxidase, augmenting the endogenous antioxidant defense system, and diminishing the accumulation of 4-hydroxynonenal and 3-nitrotyrosine in renal tissues. Furthermore, reduced levels of proinflammatory cytokines such as tumor necrosis factor-alpha and interleukin-1 beta indicated that CP-induced renal inflammation was mitigated upon the treatment with GP. GP also attenuated the CP-induced activation of mitogen-activated protein kinases, excessive activities of caspase-3/7 and poly(ADP-ribose) polymerase, DNA fragmentation, and apoptosis. When administered 12 h after the onset of kidney injury, GP showed a therapeutic effect by ameliorating CP-induced nephrotoxicity. Moreover, GP synergistically enhanced the CP-induced cell death of T24 human bladder cancer cells. Collectively, our data indicate that GP attenuated the CP-induced renal tissue injury by abrogating oxidative/nitrative stress and inflammation and by blocking cell death pathways, thereby improving the renal function. Thus, our results suggest that the use of GP may be a promising new protective strategy against cisplatin-induced nephrotoxicity. [ABSTRACT FROM AUTHOR]

The consequences of chronic exposure of organophosphorus compounds (OPCs) on diabetic subjects have been seldom reported. The aim of the present study was to assess the impact of non-lethal dose of terbufos sulfone (TS), an organophosphate, on the kidney of non-diabetic and streptozotocin (STZ)-induced diabetic rats. The diabetogenic effect of TS was also examined. Male Wistar rats were treated for two weeks with 130 µg/kg body weight/day of TS. This dose was 1/20 of LD50 and produces less than 10% inhibition of acetylcholinesterase (AChE) in non-diabetic rats. No observable symptoms of poisoning were noted. Weight, glucose and in vivo red blood cell (RBC)-AChE were measured on day 7 and 15 of the study. Serum biochemistry, urine analysis, and transmission electron microscopy (TEM) of kidney were performed to assess the toxicity at the end of the 15-day study. Our results did not reveal diabetogenic effect of TS treatment. Blood glucose level was significantly increased and RBC-AChE activity was significantly decreased in diabetic-TS treated rats compared to untreated diabetic and normal control animals. TEM of kidney revealed structural damage to kidney, which was more severe in diabetic-TS treated rats compared to controls. Toxicity to kidney by TS was further confirmed by urine and blood biochemistry. Our results conclude that non-lethal dose of TS aggravates the nephrotoxicity in diabetic rats. Further studies with other OPCs are needed to be able to generalize the diabetogenic effect of TS. [ABSTRACT FROM AUTHOR]

Abstract: Nociceptin and nocistatin are endogenous ligands of G protein coupled receptor family. Numerous techniques have been used to study the diverse parameters including, localization, distribution and ultrastructure of these peptides. The majority of the study parameters are based on their physiological roles in different organ systems. The present study presents an overview of the different methods used for the study of nociceptin, nocistatin and their receptors. Nociceptin has been implicated in many physiological functions including, nociception, locomotion, stressed-induced analgesia, learning and memory, neurotransmitter and hormone release, renal function, neuronal differentiation, sexual and reproductive behavior, uterine contraction, feeding, anxiety, gastrointestinal motility, cardiovascular function, micturition, cough, hypoxic–ischemic brain injury, diuresis and sodium balance, temperature regulation, vestibular function, and mucosal transport. It has been noted that the use of light and electron microscopy was less frequent, though it may be one of the most promising tools to study the intracellular localization of these neuropeptides. In addition, more studies on the level of circulating nociceptin and nocistatin are also necessary for investigating their clinical roles in health and disease. A variety of modern tools including physiological, light and electron microscopy (EM) are needed to decipher the extent of intracellular localization, tissue distribution and function of these peptides. The intracellular localization of nociceptin and nocistatin will require a high resolution transmission EM capable of identifying these peptides and other supporting molecules that co-localize with them. A tracing technique could also elucidate a possible migratory ability of nociceptin and nocistatin from one cellular compartment to the other. [Copyright &y& Elsevier]

Given the clinical prevalence of type 2 diabetes and obesity and their association with high mortality linked to cardiovascular disease, the aim of the study was to investigate the effects of feeding type 2 diabetic Goto-Kakizaki (GK) rats either high- or low-fat diets on cardiomyocyte structure and function. The GK rats were fed either a high-fat diet (HFD) or a low-fat diet (LFD) from the age of 2 months for a period of 7 months. The GK-HFD rats gained more weight, ate less food and drank less water compared with GK-LFD rats. At 7 months, non-fasting blood glucose was higher in GK-LFD (334 ± 35 mg dl−1) compared with GK-HFD rats (235 ± 26 mg dl−1). Feeding GK rats with a HFD had no significant effect on glucose clearance following a glucose challenge. Time-to-peak ( tpeak) shortening was reduced in myocytes from GK-HFD (131.8 ± 2.1 ms) compared with GK-LFD rats (144.5 ± 3.0 ms), and time-to-half ( t1/2) relaxation of shortening was also reduced in myocytes from GK-HFD (71.7 ± 6.9 ms) compared with GK-LFD rats (86.1 ± 3.6 ms). The HFD had no significant effect on the amplitude of shortening. The HFD had no significant effect on tpeak, t1/2 decay, amplitude of the Ca2+ transient, myofilament sensitivity to Ca2+, sarcoplasmic reticulum Ca2+ content, fractional release of Ca2+ and the rate of Ca2+ uptake. Structurally, ventricular myocytes from GK-HFD rats showed extensive mitochondrial lesions, including swelling, loss of cristae, and loss of inner and outer membranes, resulting in gross vacuolarization and deformation of ventricular mitochondria with a subsequent reduction in mitochondrial density. Expression of genes encoding various L-type Ca2+ channel proteins (Cacnb2) and cardiac muscle proteins (Myl2 and Atp2a1) were downregulated in GK-HFD compared with GK-LFD rats. Structural lesions and changed expression of genes encoding various cardiac muscle proteins might partly underlie the altered time course of myocyte shortening and relaxation in myocytes from GK-HFD compared with GK-LFD rats. [ABSTRACT FROM AUTHOR]

Our recent studies have demonstrated that aspirin treatment prevents inflammatory and oxidative stress-induced alterations in mitochondrial function, improves glucose tolerance and pancreatic endocrine function and preserves tissue-specific glutathione (GSH)-dependent redox homeostasis in Goto-Kakizaki (GK) diabetic rats. In the current study, we have investigated the mechanism of action of aspirin in maintaining mitochondrial bioenergetics and redox metabolism in the liver and kidneys of GK rats. Aspirin reduced the production of reactive oxygen species (ROS) and oxidative stress-induced changes in GSH metabolism. Aspirin treatment also improved mitochondrial respiratory function and energy metabolism, in addition to regulating the expression of cell signaling proteins that were altered in diabetic animals. Ultrastructural electron microscopy studies revealed decreased accumulation of glycogen in the liver of aspirin-treated diabetic rats. Hypertrophic podocytes with irregular fusion of foot processes in the renal glomerulus and detached microvilli, condensed nuclei and degenerated mitochondria observed in the proximal convoluted tubules of GK rats were partially restored by aspirin. These results provide additional evidence to support our previous observation of moderation of diabetic complications by aspirin treatment in GK rats and may have implications for cautious use of aspirin in the therapeutic management of diabetes. [ABSTRACT FROM AUTHOR]

In vivo biotelemetry studies have demonstrated a variety of heart rhythm disturbances in type 1 diabetes mellitus. In the streptozotocin (STZ)-induced diabetic rat, these disturbances have included reductions in heart rate (HR) and heart rate variability (HRV) and an electrocardiogram that displays prolonged QRS duration and Q–T interval. The aim of this study was to investigate the chronic effects of type 2 diabetes mellitus on heart rhythm in the Goto–Kakizaki (GK) rat. Transmitter devices were surgically implanted in the peritoneal cavity of young male GK and age-matched Wistar control rats. Electrodes from the transmitter were arranged in Einthoven bipolar lead II configuration. Electrocardiogram, physical activity and body temperature data were recorded in rats from age 2 to 15 months. Data were acquired for 2 weeks each month. Non-fasting blood glucose, glucose tolerance and body weight were measured periodically. In GK rats, growth rate and maximal attained body weight were significantly reduced and non-fasting blood glucose was progressively increased compared with age-matched Wistar control animals. Heart rate was significantly lower in GK compared with control rats at 2, 7 and 15 months of age. At 2 months of age, HR was 316 ± 6 beats min−1 in GK rats compared with 370 ± 7 beats min−1 in Wistar control animals. There was a progressive age-dependent decline in HRV in Wistar control rats; however, HRV in GK rats did not alter significantly with age. Heart rate variability was significantly reduced in GK compared with Wistar control rats at 2 and 7 months. At 2 months of age, HRV was 28 ± 2 beats min−1 in GK rats compared with 38 ± 3 beats min−1 in Wistar control rats. Reduced HR in GK rats may be an inherited characteristic. The absence of age-dependent reductions in HRV in GK rats may be a consequence of an underlying impairment of autonomic control which manifests at early age. [ABSTRACT FROM AUTHOR]

Tribulus terrestris L ( TT) is used in the Arabic folk medicine to treat various diseases. The aim of this article was to investigate the protective effects of TT in diabetes mellitus (DM). Diabetes is known to increase reactive oxygen species (ROS) level that subsequently contributes to the pathogenesis of diabetes. Rats were divided into six groups and treated with either saline, glibenclamide (Glib), or TT for 30 days. Rats in group 1 were given saline after the onset of streptozotocin (STZ)-induced diabetes; the second diabetic group was administered Glib (10 mg/kg body weight). The third diabetic group was treated with the TT extract (2 g/kg body weight), while the first, second, and third nondiabetic groups were treated with saline solution, Glib, and TT extract, respectively. At the end of the experiment, serum and liver samples were collected for biochemical and morphological analysis. Levels of serum alanine aminotransferase (ALT) and creatinine were estimated. In addition, levels of malondialdehyde (MDA) and reduced glutathione (GSH) were assayed in the liver. The tested TT extract significantly decreased the levels of ALT and creatinine in the serum ( P < 0.05) in diabetic groups and lowered the MDA level in liver ( P < 0.05) in diabetic and ( P < 0.01) nondiabetic groups. On the other hand, levels of reduced GSH in liver were significantly increased ( P < 0.01) in diabetic rats treated with TT. Histopathological examination revealed significant recovery of liver in herb-treated rats. This investigation suggests that the protective effect of TT for STZ-induced diabetic rats may be mediated by inhibiting oxidative stress. [ABSTRACT FROM AUTHOR]

Cations play major physiological and biochemical roles in the excitation–contraction coupling processes in the heart. This study investigated the effect of streptozotocin (STZ)-induced type I diabetes mellitus (DM) on contraction, calcium transient [Ca2+]i, and cation contents in the isolated rat heart compared to age-matched control. Diabetes rats weighed significantly ( P < 0.05) less compared to control. They also had significantly ( P < 0.05) elevated blood glucose compared to control. The whole heart, as well as the atria, right and left ventricles of the diabetic heart weighed significantly ( P < 0.05) less compared to hearts from age control rats. The force of contraction and time to peak (t-pk) contraction in diabetic ventricular myocytes increased significantly ( P < 0.05) compared to control. By contrast, these parameters did not change for the Ca2+ transient except for the time to half (t½) relaxation. The levels of sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), iron (Fe2+), copper (Cu2+), and zinc (Zn2+) in the hearts varied from diabetic compared to control animals. The results indicate that 6–8 weeks of STZ-induced DM is associated with marked changes in contraction and in cation contents of the heart. The delay in the t½ relaxation of the Ca2+ transient may be responsible for the elevated contraction seen in the diabetic heart. Moreover, the changes in cation contents in the heart may be responsible for abnormal cardiac rhythms and activity during DM. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) is a major health problem at present affecting about 180 million people worldwide. DM is associated with many metabolic abnormalities in the body including the indigestion of carbohydrates leading to malnutrition and weight loss. In this article we investigate the cellular and molecular mechanisms of exocrine pancreatic insufficiency in streptozotocin (STZ, 60 mg kg−1, i.p.)-induced DM in male rats compared to healthy age-matched controls. Either electrical field stimulation (EFS) or cholecystokinin octapeptide (CCK-8, 10−8 M) can elicit large and significant ( P < 0.05) increases in amylase output from pancreatic segments compared to basal secretion. Insulin (10−6 M) alone has no significant effect on amylase output compared to basal but it enhanced the secretory responses to either EFS or CCK-8. When rats were rendered diabetic with STZ, either EFS or CCK-8-evoked amylase output was significantly ( P < 0.01) decreased compared to the responses obtained with either EFS or CCK-8 alone in healthy age-matched control pancreas. In addition, CCK-8 can elicit large dose-dependent release of amylase in age-matched control and diabetic acinar cells with significantly ( P < 0.05) reduced responses in diabetic acinar cells. CCK-8 evoked a large rapid increase in peak cytosolic free calcium concentration ([Ca2+]c) followed by a decrease to a plateau phase in age-matched control fura-2-loaded pancreatic acinar cells. These responses were significantly ( P < 0.05) decreased in STZ-induced diabetic acinar cells. In the presence of 10−6 M insulin, CCK-8 evoked a much larger increase in the Ca2+ transient compared to the response obtained with CCK-8 alone. These effects were significantly ( P < 0.01) inhibited in STZ-induced diabetic acinar cells. Similarly, in zero extracellular Ca2+[Ca2+]ĉ, the CCK-8-evoked [Ca2+]c was significantly ( P < 0.05) reduced in both diabetic and age-matched control acinar cells, but with more pronounced reduction in diabetic acinar cells. CCKA receptor mRNA levels remained unchanged in diabetic rat acinar cells compared to age-matched healthy control. In contrast, amylase mRNA was significantly ( P < 0.05) reduced in diabetic acinar cells compared to control. The results indicate that reduced amylase secretion in response to either EFS or CCK-8 in the diabetic pancreas may be due to reduced [Ca2+]c and gene expression for amylase and not to the gene expression of CCKA receptor in pancreatic acinar cells. [ABSTRACT FROM AUTHOR]

Lipocalin-2 (LCN-2) is a novel, 198 amino acid adipocytokine also referred to as neutrophil gelatinase-associated lipocalin (NGAL). LCN-2 is a circulatory protein responsible for the transportation of small and hydrophobic molecules (steroid, free fatty acids, prostaglandins and hormones) to target organs after binding to megalin/glycoprotein and GP330 SLC22A17 or 24p3R LCN-2 receptors. LCN-2 has been used as a biomarker for acute and chronic renal injury. It is present in a large variety of cells including neutrophil, hepatocytes, lung, bone marrow, adipose tissue, macrophages, thymus, non-neoplastic breast duct, prostate, and renal cells. Different functions have been associated with LCN-2. These functions include antibacterial, anti-inflammatory, and protection against cell and tissue stress. Moreover, LCN-2 can increase the pool of matrix metalloproteinase 9 in human neutrophil granulocytes. Other reported functions of LCN-2 include its ability to destroy the extracellular matrix, which could enable cancer progression and spread of metastasis. Recent reports show that the tissue level of LCN-2 is increased in metabolic disorders such as obesity and type 2 diabetes, suggesting an association between LCN-2 and insulin sensitivity and glucose homeostasis. The precise role of LCN-2 in the modulation of insulin sensitivity, glucose and lipid metabolism is still unclear. This review explores the structure of LCN-2, tissue distribution, and its interaction with important metabolic pathways. [Display omitted] • Lipocalin-2 (LCN-2) is distributed in many tissues including the lung, heart and kidney. • LCN-2 is capable of destroying the extracellular matrix. • It has antibacterial effect. • It is upregulated by the NF-κB, ERK and JAK-STAT signaling pathways. • LCN-2 is a biomarker of renal acute and chronic injury. [ABSTRACT FROM AUTHOR]

• AOC3 inhibitors exert protective effect on STZ-induced pancreatic beta cell damage. • AOC3 inhibitors attenuate neuropathic cold hypersensitivity. • AOC3 inhibitors ameliorate diabetic retinal dysfunction. • The multi-target AOC3 inhibitor SZV 1287 has antiapoptotic effect in the retina. • The analgesic candidate SZV 1287 does not exert major side effects upon 8 weeks. Diabetes mellitus is a common metabolic disease leading to hyperglycemia due to insufficient pancreatic insulin production or effect. Amine oxidase copper containing 3 (AOC3) is an enzyme that belongs to the semicarbazide-sensitive amine oxidase family, which may be a novel therapeutic target to treat diabetic complications. We aimed to explore the effects of AOC3 inhibition and to test the actions of our novel AOC3 inhibitor multi-target drug candidate, SZV 1287, compared to a selective reference compound, LJP 1207, in an 8-week long insulin-controlled streptozotocin (STZ)-induced (60 mg/kg i.p.) rat diabetes model. Both AOC3 inhibitors (20 mg/kg, daily s.c. injections) were protective against STZ-induced pancreatic beta cell damage determined by insulin immunohistochemistry and radioimmunoassay, neuropathic cold hypersensitivity measured by paw withdrawal latency decrease from 0 °C water, and retinal dysfunction detected by electroretinography. SZV 1287 showed greater inhibitory effects on beta cell damage, and reduced retinal apoptosis shown by histochemistry. Mechanical hypersensitivity measured by aesthesiometry, cardiac dysfunction and nitrosative stress determined by echocardiography and immunohistochemistry/Western blot, respectively, serum Na+, K+, fructosamine, and urine microalbumin, creatinine, total protein/creatinine ratio alterations did not develop in response to diabetes. None of these parameters were influenced by the treatments except for SZV 1287 reducing serum fructosamine and LJP 1207 increasing urine creatinine. We provide the first evidence for protective effects of AOC3 inhibition on STZ-induced pancreatic beta cell damage, neuropathic cold hypersensitivity and diabetic retinal dysfunction. Long-term treatment with our novel multi-target analgesic candidate, SZV 1287, is safe and effective also under diabetic conditions. [ABSTRACT FROM AUTHOR]

Oxidative stress, fibrosis, and inflammasome activation from advanced glycation end product (AGE)-receptor of advanced glycation end product (RAGE) interaction contribute to diabetic cardiomyopathy (DCM) formation and progression. Our study revealed the impact of β -caryophyllene (BCP) on activating cannabinoid type 2 receptors (CB2Rs) against diabetic complication, mainly cardiomyopathy and investigated the underlying cell signaling pathways in mice. The murine model of DCM was developed by feeding a high-fat diet with streptozotocin injections. After the development of diabetes, the animals received a 12-week oral BCP treatment at a dose of 50 mg/kg/body weight. BCP treatment showed significant improvement in glucose tolerance and insulin resistance and enhanced serum insulin levels in diabetic animals. BCP treatment effectively reversed the heart remodeling and restored the phosphorylated troponin I and sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a expression. Ultrastructural examination showed reduced myocardial cell injury in DCM mice treated with BCP. The preserved myocytes were found to be associated with reduced expression of AGE/RAGE in DCM mice hearts. BCP treatment mitigated oxidative stress by inhibiting expression of NADPH oxidase 4 and activating phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. Also, BCP suppressed cardiac fibrosis and endothelial-to-mesenchymal transition in DCM mice by inhibiting transforming growth factor β (TGF-β)/suppressor of mothers against decapentaplegic (Smad) signaling. Further, BCP treatment suppressed nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome activation in DCM mice and alleviated cellular injury to the pancreatic tissues evidenced by significant elevation of the number of insulin-positive cells. To demonstrate a CB2R-dependent mechanism of BCP, another group of DCM mice were pretreated with AM630, a CB2R antagonist. AM630 was observed to abrogate the beneficial effects of BCP in DCM mice. Taken together, BCP demonstrated the potential to protect the myocardium and pancreas of DCM mice mediating CB2R-dependent mechanisms. SIGNIFICANCE STATEMENT: BCP, a CB2R agonist, shows protection against DCM. BCP attenuates oxidative stress, inflammation, and fibrosis in DCM via activating CB2Rs. BCP mediating CB2R activation favorably modulates AGE/RAGE, PI3K/AKT/Nrf2 β and TGF- β /Smad and (NLRP3) inflammasome in diabetic cardiomyopathy., (Copyright © 2024 by The American Society for Pharmacology and Experimental Therapeutics.)

Lipids are primarily transported in the bloodstream by lipoproteins, which are macromolecules of lipids and conjugated proteins also known as apolipoproteins. The processes of lipoprotein assembly, secretion, transportation, modification, and clearance are crucial components of maintaining a healthy lipid metabolism. Disruption in any of these steps results in pathophysiological abnormalities such as dyslipidemia, obesity, insulin resistance, inflammation, atherosclerosis, peripheral artery disease, and cardiovascular diseases. By studying these genetic mutations, researchers can gain valuable insights into the underlying mechanisms that govern the relationship between protein structure and its physiological role. These lipoproteins, including HDL, LDL, lipoprotein(a), and VLDL, mainly serve the purpose of transporting lipids between tissues and organs. However, studies have provided evidence that apo(a) also possesses protective properties against pathogens. In the future, the field of study will be significantly influenced by the integration of recombinant DNA technology and human site-specific mutagenesis for treating hereditary disorders. Several medications are available for the treatment of dyslipoproteinemia. These include statins, fibrates, ezetimibe, niacin, PCSK9 inhibitors, evinacumab, DPP 4 inhibitors, glucagon-like peptide-1 receptor agonists GLP1RAs, GLP-1, and GIP dual receptor agonists, in addition to SGLT2 inhibitors. This current review article exhibits, for the first time, a comprehensive reflection of the available body of publications concerning the impact of lipoproteins on metabolic well-being across various pathological states.

Introduction: Brain histamine is considered an endogenous anticonvulsant and histamine H1 receptor. H1R antagonists have, in earlier studies, been found to induce convulsions. Moreover, research during the last two decades has provided more information concerning the anticonvulsant activities of histamine H3R (H3R) antagonists investigated in a variety of animal epilepsy models. Methods: Therefore, the in vivo anticonvulsant effect of the H3R antagonist DL76, with proven high in vitro affinity, in vitro selectivity profile, and high in vivo antagonist potency in mice against maximal electroshock (MES)-induced seizures in mice, was assessed. Valproic acid (VPA) was used as a reference antiepileptic drug (AED). In addition, DL76 was tested for its reproductive and fetal toxicity in the same animal species. Results and discussion: Our observations showed that acute systemic administration (intraperitoneal; i.p.) of DL76 (7.5 mg/kg, 15 mg/kg, 30 mg/kg, and 60 mg/kg, i.p.) provided significant and dose-dependent protection against MES-induced seizures in female and male mice. Moreover, the DL76-provided protective effects were comparable to those offered by the VPA and were reversed when animals were co-administered the CNS-penetrant selective H3R agonist R -(α)-methylhistamine (RAM, 10 mg/kg, i.p.). Furthermore, the administration of single (7.5 mg/kg, 15 mg/kg, 30 mg/kg, or 60 mg/kg, i.p.) or multiple doses (3 × 15 mg/kg, i.p.) of H3R antagonist DL76 on gestation days (GD) 8 or 13 failed to affect the maternal body weight of mice when compared with the control mice group. No significant alterations were detected in the average number of implantations and resorptions between the control and DL76-treated groups at the early stages of gestation and the organogenesis period. In addition, no significant differences in the occurrence of skeletal abnormalities, urogenital abnormalities, exencephaly, exomphalos, facial clefts, and caudal malformations were observed. The only significant abnormalities witnessed in the treated groups of mice were in the length of long bones and body length. In conclusion, the novel H3R antagonist DL76 protected test animals against MES-induced seizures and had a low incidence of reproductive and fetal malformation with decreased long bone lengths in vivo , signifying the potential therapeutic value of H3R antagonist DL76 for future preclinical as well as clinical development for use in the management of epilepsy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Bastaki, Abdulrazzaq, Zidan, Shafiullah, Alaryani, Alnuaimi, Adeghate, Mohsin, Akour, Siwek, Łażewska, Kieć-Kononowicz and Sadek.)

Diabetes mellitus (DM) is a chronic metabolic disease marked by hyperglycemia due to insulin deficiency or insulin resistance leading to many chronic complications. It is thus important to manage diabetes effectively in order to prevent and or delay these complications. Melatonin is produced by the pineal gland and regulates the wake-sleep circadian rhythm. Existing evidence suggests that melatonin may be effective in the management of DM. However, the evidence on the mechanism of the beneficial effect melatonin as a treatment for DM is limited. In this study, we investigated the effect of melatonin treatment on blood glucose, insulin (INS), AKT and superoxide dismutase (SOD) gene levels in diabetic rats. Non-diabetic and diabetic rats were treated orally for 4 weeks with either 25 mg or 50 mg/kg body weight of melatonin. At the end of the study, pancreatic and liver tissues morphology, glucose homeostasis, serum insulin and SOD levels, hepatic gene and protein expression of SOD as protecting antioxidant enzyme and AKT as central element involved in PI3K/AKT insulin signaling pathway were estimated. Melatonin treated diabetic rats showed reduced hyperglycemia, and increased serum insulin and SOD levels. In addition, melatonin induced an increased gene and protein expression of SOD and AKT. In conclusion, melatonin may play a role in treating diabetic rats via stimulation of insulin secretion, insulin signaling and reduction in oxidative stress., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Introduction: Nonalcoholic fatty liver disease (NAFLD) is the most common hepatic disease affecting almost 30% of the world population. Approximately 25% of people with NAFLD develop nonalcoholic steatohepatitis (NASH), the fulminant version of the disease. Diabetes mellitus is present in 22.5% of people with NAFLD and 44.60% of individuals with NASH. This review was undertaken to examine the current contribution of glucagon-like peptide 1 (GLP-1) receptor agonists to the pharmacotherapy of diabetic nonalcoholic steatohepatitis., Areas Covered: The author analyzed the current status of GLP-1 receptor agonists for pharmacotherapy of diabetic NASH. Research data and literature reports were taken from the database and or websites of Diabetes UK, American Diabetes Association, ClinicalTrials.gov, PubMed, and Scopus. The keywords utilized included type 2 diabetes, GLP-1, NASH, NAFLD, and clinical trials., Expert Opinion: Since diabetic NASH is associated with obesity, diabetes mellitus, oxidative stress and inflammation, drugs capable of mitigating all of these conditions simultaneously, are most ideal for the treatment of diabetic NASH. These drugs include (in order of relevance), GLP-1 receptor agonists, GLP-1 and GIP dual receptor agonists, sodium-glucose co-transporter-2 (SGLT2) inhibitors, and pioglitazone. The future, FDA-approved drug for diabetic NASH treatment will likely be GLP-1 agonist, which could be used as monotherapy or in combination with other drugs.

Recent studies have implicated pre-beta and beta lipoproteins (VLDL and LDL) in the etiopathogenesis of complications of diabetes mellitus (DM). In contrast, alpha lipoprotein (HDL) is protective of the beta cells of the pancreas. This study examined the distribution of HDL in the islets of Langerhans of murine models of type 1 diabetic rats (streptozotocin (STZ)-induced DM in Wistar rats) and type 2 models of DM rats (Goto-Kakizaki (GK), non-diabetic Zucker lean (ZL), and Zucker diabetic and fatty (ZDF)). The extent by which HDL co-localizes with insulin or glucagon in the islets of the pancreas was also investigated. Pancreatic tissues of Wistar non-diabetic, diabetic Wistar, GK, ZL, and ZDF rats were processed for immunohistochemistry. Pancreatic samples of GK rats fed with either a low-fat or a high-fat diet were prepared for transmission immune-electron microscopy (TIEM) to establish the cytoplasmic localization of HDL in islet cells. HDL was detected in the core and periphery of pancreatic islets of Wistar non-diabetic and diabetic, GK, ZL, and ZDF rats. The average total of islet cells immune positive for HDL was markedly (<0.05) reduced in GK and ZDF rats in comparison to Wistar controls. The number of islet cells containing HDL was also remarkably ( p < 0.05) reduced in Wistar diabetic rats and GK models fed on high-fat food. The co-localization study using immunofluorescence and TIEM techniques showed that HDL is detected alongside insulin within the secretory granules of β-cells. HDL did not co-localize with glucagon. This observation implies that HDL may contribute to the metabolism of insulin.

Background: Osteoporosis is a significant co-morbidity of type 1 diabetes mellitus (DM1) leading to increased fracture risk. Exercise-induced hormone 'irisin' in low dosage has been shown to have a beneficial effect on bone metabolism by increasing osteoblast differentiation and reducing osteoclast maturation, and inhibiting apoptosis and inflammation. We investigated the role of irisin in treating diabetic osteopathy by observing its effect on trabecular bone., Methods: DM1 was induced by intraperitoneal injection of streptozotocin 60 mg/kg body weight. Irisin in low dosage (5 µg twice a week for 6 weeks I/P) was injected into half of the control and 4-week diabetic male Wistar rats. Animals were sacrificed six months after induction of diabetes. The trabecular bone in the femoral head and neck was analyzed using a micro-CT technique. Bone turnover markers were measured using ELISA, Western blot, and RT-PCR techniques., Results: It was found that DM1 deteriorates the trabecular bone microstructure by increasing trabecular separation (Tb-Sp) and decreasing trabecular thickness (Tb-Th), bone volume fraction (BV/TV), and bone mineral density (BMD). Irisin treatment positively affects bone quality by increasing trabecular number p < 0.05 and improves the BMD, Tb-Sp, and BV/TV by 21-28%. The deterioration in bone microarchitecture is mainly attributed to decreased bone formation observed as low osteocalcin and high sclerostin levels in diabetic bone samples p < 0.001. The irisin treatment significantly suppressed the serum and bone sclerostin levels p < 0.001, increased the serum CTX1 levels p < 0.05, and also showed non-significant improvement in osteocalcin levels., Conclusions: This is the first pilot study to our knowledge that shows that a low dose of irisin marginally improves the trabecular bone in DM1 and is an effective peptide in reducing sclerostin levels., Competing Interests: The authors declare that they have no competing interests., (© 2023 Mohsin et al.)

Diabetes mellitus (DM) and its associated complications are considered one of the major health risks globally. Among numerous complications, diabetic cardiomyopathy (DCM) is characterized by increased accumulation of lipids and reduced glucose utilization following abnormal lipid metabolism in the myocardium along with oxidative stress, myocardial fibrosis, and inflammation that eventually result in cardiac dysfunction. The abnormal metabolism of lipids plays a fundamental role in cardiac lipotoxicity following the occurrence and development of DCM. Recently, it has been revealed that cannabinoid type-2 (CB2) receptors, an essential component of the endocannabinoid system, play a crucial role in the pathogenesis of obesity, hyperlipidemia, and DM. Provided the role of CB2R in regulating the glucolipid metabolic dysfunction and its antioxidant as well as anti-inflammatory activities, we carried out the current study to investigate the protective effects of a selective CB2R agonist, β-caryophyllene (BCP), a natural dietary cannabinoid in the murine model of DCM and elucidated the underlying pharmacological and molecular mechanisms. Mice were fed a high-fat diet for 4 weeks followed by a single intraperitoneal injection of streptozotocin (100 mg/kg) to induce the model of DCM. BCP (50 mg/kg body weight) was given orally for 12 weeks. AM630, a CB2R antagonist, was given 30 min before BCP treatment to demonstrate the CB2R-dependent mechanism of BCP. DCM mice exhibited hyperglycemia, increased serum lactate dehydrogenase, impaired cardiac function, and hypertrophy. In addition, DCM mice showed alternations in serum lipids and increased oxidative stress concomitant to reduced antioxidant defenses and enhanced cardiac lipid accumulation in the diabetic heart. DCM mice also exhibited activation of TLR4/NF-κB/MAPK signaling and triggered the production of inflammatory cytokines and inflammatory enzyme mediators. However, treatment with BCP exerted remarkable protective effects by favorable modulation of the biochemical and molecular parameters, which were altered in DCM mice. Interestingly, pretreatment with AM630 abrogated the protective effects of BCP in DCM mice. Taken together, the findings of the present study demonstrate that BCP possesses the capability to mitigate the progression of DCM by inhibition of lipotoxicity-mediated cardiac oxidative stress and inflammation and favorable modulation of TLR4/NF-κB/MAPK signaling pathways mediating the CB2R-dependent mechanism., Competing Interests: The authors declare no competing financial interest., (© 2023 American Chemical Society.)

(1) Background: Cardiovascular complications are a leading cause of morbidity and mortality in diabetic patients. The effects of obesity and diabesity on the function and structure of ventricular myocytes in the Zucker fatty (ZF) rat and the Zucker diabetic fatty (ZDF) rat compared to Zucker lean (ZL) control rats have been investigated. (2) Methods: Shortening and intracellular Ca 2+ were simultaneously measured with cell imaging and fluorescence photometry, respectively. Ventricular muscle protein expression and structure were investigated with Western blot and electron microscopy, respectively. (3) Results: The amplitude of shortening was increased in ZF compared to ZL but not compared to ZDF myocytes. Resting Ca 2+ was increased in ZDF compared to ZL myocytes. Time to half decay of the Ca 2+ transient was prolonged in ZDF compared to ZL and was reduced in ZF compared to ZL myocytes. Changes in expression of proteins associated with cardiac muscle contraction are presented. Structurally, there were reductions in sarcomere length in ZDF and ZF compared to ZL and reductions in mitochondria count in ZF compared to ZDF and ZL myocytes. (4) Conclusions: Alterations in ventricular muscle proteins and structure may partly underlie the defects observed in Ca 2+ signaling in ZDF and ZF compared to ZL rat hearts.

Cisplatin (CP) treatment has been long associated with the development of acute kidney injury (AKI) through mechanisms involving inflammation and oxidative stress. α-Bisabolol (BIS), a sesquiterpene alcohol isolated from the essential oil of various plants, including chamomile, has garnered popularity lately due to its antioxidant, anti-inflammatory, and anticancer properties. Therefore, we investigated the nephroprotective effects of BIS in the murine model of CP-induced AKI and the underlying mechanism of action. BALB/c mice were given BIS orally at 25 mg/kg for 7 days. On day 7, they were given a single dose of CP at 20 mg/kg intraperitoneally. BIS treatment continued for 3 more days. The animals were sacrificed at the end of the experiment (day 11). Kidneys, plasma, and urine were collected, and subsequently, various physiological, biochemical, and histological parameters were assessed. BIS has significantly normalized the alterations of water intake, urine volume, relative kidney weight, and the concentrations of urea and creatinine, as well as the creatinine clearance induced by CP treatment. BIS significantly mitigated the effects of CP-induced kidney injury by reducing kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, adiponectin, and cystatin C. Likewise, the renal concentrations of proinflammatory cytokines, tumor necrosis factor α, interleukin (IL)-6 and IL-1β that were elevated in CP group were significantly reduced in mice treated with BIS and CP. A similar significant reduction was also observed in the CP-induced augmented levels of markers of oxidative stress, as well as the metabolite pteridine. Moreover, BIS significantly reduced the CP-induced renal DNA damage, and markedly lessened the acute tubular necrosis observed in kidney histology. Additionally, BIS significantly reduced the CP-induced increase in the phosphorylated nuclear factor κB (NFκB) in the kidney. These data strongly suggest that BIS exerts a protective action against CP-induced nephrotoxicity by mitigating inflammation and oxidative stress through the inhibition of NFκB activation. No overt adverse effects were noted with BIS treatment. Additional investigations should be done to consider BIS as an efficacious nephroprotective agent against CP.

Targeting oxidative stress and inflammation by novel dietary compounds of natural origin convincingly appears to be one of the most important therapeutic strategies to keep inflammatory bowel diseases (IBD) such as ulcerative colitis disease in remission. It is imperative to investigate naturally occuring plant-derived dietary phytochemicals that are receiving attention for their therapeutic benefits to overcome the debilitating conditions of IBD. In the present study, the effect of nerolidol (NRD), a monocyclic sesquiterpene found in German Chamomile tea, was investigated in acetic acid-induced colitis model in Wistar rats. NRD was orally administered at a dose of 50 mg/kg/day either for 3 days before or 30 min after induction of IBD for 7 days, after intrarectal administration of acetic acid. The body weight, macroscopic, and microscopic analyses of the colon in different experimental groups were observed on days 0, 2, 4, and 7. Acetic acid caused significant reduction in body weight and induced macroscopic and microscopic ulcer along with a significant decline of antioxidants, concomitant to increased malondialdehyde (MDA), a marker of lipid peroxidation, and myeloperoxidase (MPO) activity, a marker of neutrophil activation. Treatment with NRD significantly improved IBD-induced reduction in body weight, improved histology, inhibited MDA formation, and restored antioxidants along with reduced MPO activity. Acetic acid also induced the release of pro-inflammatory cytokines and increased calprotectin, released by neutrophils under inflammatory conditions. NRD treatment significantly reduced calprotectin and pro-inflammatory cytokines. NRD treatment showed potential to improve disease activity and inhibit oxidative stress, lipid peroxidation, and inflammation along with histological preservation of the colon tissues., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.)

Nociceptin (NC) consists of 17 amino acids (aa) and takes part in the processing of learning and memory. The role of NC in the induction of endogenous antioxidants in still unclear. We examined the effect of NC on the expression of endogenous antioxidants in kidney, liver, cerebral cortex (CC), and hippocampus after the onset of diabetes mellitus, using enzyme-linked immunosorbent assay and immunohistochemistry. Exogenous NC (aa chain 1-17; 10 µg/kg body weight) was given intraperitoneally to normal and diabetic rats for 5 days. Our results showed that catalase (CAT) is present in the proximal (PCT) and distal (DCT) convoluted tubules of kidney, hepatocytes, and neurons of CC and hippocampus. The expression of CAT was significantly ( p < 0.05) reduced in the kidney of normal and diabetic rats after treatment with NC. However, NC markedly ( p < 0.001) increased the expression CAT in the liver and neurons of CC of diabetic rats. Superoxide dismutase (SOD) is widely distributed in the PCT and DCT of kidney, hepatocytes, and neurons of CC and hippocampus. NC significantly ( p < 0.001) increased the expression of SOD in hepatocytes and neurons of CC and the hippocampus but not in the kidney. Glutathione reductase (GRED) was observed in kidney tubules, hepatocytes and neurons of the brain. NC markedly increased ( p < 0.001) the expression of GRED in PCT and DCT cells of the kidney and hepatocytes of liver and neurons of CC. In conclusion, NC is a strong inducer of CAT, SOD, and GRED expression in the kidney, liver and brain of diabetic rats.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) has infected more than 42.5 million people globally resulting in the death of over 1.15 million subjects. It has inflicted severe public health and economic hardships across the world. In addition to acute respiratory distress syndrome, respiratory failure, sepsis, and acute kidney injury, COVID-19 also causes heart failure (HF). COVID-19-induced HF is manifested via different mechanisms, including, but not limited to, (1) virus-induced infiltration of inflammatory cells, which could impair the function of the heart; (2) pro-inflammatory cytokines (monocyte chemoattractant protein-1, interleukin-1β; interleukin-6; tumor necrosis factor-α) that could cause necrosis and death of the myocardium; (3) endothelial injury coupled with micro-thrombosis which could damage the endocardium; and (4) acute respiratory distress syndrome and respiratory failure that could lead to heart failure due to severe hypoxia. It is concluded that the etiology of COVID-19-induced HF is multifactorial and mitigation of the development of HF in patients with COVID-19 will require different approaches such as social distancing, drug therapy, and the urgent development of a vaccine to eradicate the disease.

The hypocretin/orexin (Hcrt/orexin) unit affects the functions of the nervous, cardiovascular, gastrointestinal, and reproductive systems. Hcrt/orexin ligands and receptors have been localized to different parts of the central and peripheral nervous systems, cerebrospinal fluid and blood, exocrine (pancreas, salivary, lacrimal) as well as endocrine (pancreatic islets, pituitary, adrenal) glands. Several factors including stress, glucagon-like peptide-1 agonists, glutamate, nicotine, glucose, and hypoglycaemia stimulate the expression of Hcrt/orexin system, but it is inhibited by ageing, bone morphogenetic protein, hypoxia/hypercapnia, melanocortin receptor accessory protein 2, and glucagon. Literature reports show that Hcrt/orexin can significantly increase insulin secretion from normal and diabetic rat pancreata. Hcrt/orexin decreases blood glucose concentration and reduces insulin resistance partly via increased tissue expression of glucose transporter type 4. It reduces obesity by increasing browning of fat cells and energy expenditure. Taken together, Hcrt/orexin modulates obesity and the metabolism of glucose and insulin. The Hcrt/orexin system may thus be a target in the development of new therapies for the treatment of diabetes mellitus., (© 2019 John Wiley & Sons, Ltd.)

The prevalence of water-pipe tobacco smoking is increasing worldwide, and is relatively high among youth and young adults. Exposure to water-pipe smoke (WPS) has been reported to affect various systems including the respiratory, cardiovascular and reproductive systems. However, the impact of WPS exposure on the kidney has received only scant attention. Here, we assessed the effect of nose-only WPS exposure for one or four consecutive weeks on renal histology, inflammation, oxidative stress, DNA damage, and apoptosis. The duration of the session was 30 min/day and 5 days/week. Control mice were exposed to air. Light and electron microcopy analysis revealed that the WPS exposure (especially at 4-week time point) caused degeneration of the endothelial cells of the glomerular capillaries and vacuolar degenerations of the proximal convoluted tubules. WPS exposure also significantly decreased the creatinine clearance, and significantly increased proteinuria and urinary kidney injury molecule-1 (KIM-1) concentration. Kidney lipid peroxidation, reactive oxygen species, and oxidized glutathione were significantly increased. WPS exposure also affected the concentration of reduced glutathione and the activity of catalase. Likewise, renal concentrations of interleukin (IL)-6, IL-1β and KIM-1 were augmented by WPS exposure. Moreover, WPS caused DNA damage as evaluated by comet assay, and increased the expression of cleaved caspase-3 and cytochrome C in the kidney. We conclude that exposure of mice to WPS caused renal histopathological alterations, inflammation, oxidative stress, DNA damage, and apoptosis. If the latter findings could be substantiated by controlled human studies, it would be an additional cause for disquiet about an established public health concern., (Copyright © 2020 Nemmar, Beegam, Yuvaraju, Yasin, Ali and Adeghate.)

Emerging evidence demonstrates that NLRP3 inflammasome activation, lysosomal dysfunction, and impaired autophagic flux play a crucial role in the pathophysiology of myocardial infarction (MI). Therapeutic strategies targeting NLRP3 activation, lysosomal enzyme release and correcting autophagy have shown beneficial effects in suppressing early inflammatory responses in cardiovascular diseases. Thus, the agents, which inhibit NLRP3 activation and correct lysosome dysfunction and impaired autophagic flux, can be potential drugs for MI. The present study evaluated the effects and elucidated the NLRP3 inflammasome mediated mechanism of α-bisabolol, a dietary sesquiterpene alcohol in a rat model of isoproterenol (ISO)-induced MI. In the present study, male albino Wistar rats were pre- and co-treated with intraperitoneal injection of α-bisabolol (25 mg kg-1) daily for 10 days along with the subcutaneous injection of ISO (85 mg kg-1) at an interval of 24 h for two days (9th and 10th day). ISO injections induced MI as evidenced by the elevated cardiac marker enzyme in serum and altered oxidative stress markers in the total heart and lysosomal fractions. ISO also caused activation of NLRP3 inflammasomes mediating TLR4-NFκB/MAPK signaling pathways and lysosomal dysfunction along with induction and release of proinflammatory cytokines. Interestingly, treatment with α-bisabolol favorably corrected the morphological, histopathological, ultrastructural, biochemical and molecular abnormalities induced by ISO-induced MI in rats. Furthermore, the ultrastructural studies also confirmed the improvement in the autophagic mechanism. The findings of the present study clearly demonstrate that α-bisabolol attenuates oxidative stress and inflammation by inhibiting NLRP3 inflammasome activation and TLR4-NFκB/MAPK signaling pathways along with correcting lysosomal dysfunction and impaired autophagic flux. The underlying pharmacological and molecular mechanism of cardioprotection was attributed to its antioxidant, free radical scavenging and anti-inflammatory properties.

The metabolic sensor Per-Arnt-Sim (Pas) domain-containing serine/threonine kinase (PASK) is expressed predominantly in the cytoplasm of different cell types, although a small percentage is also expressed in the nucleus. Herein, we show that the nuclear PASK associates with the mammalian H3K4 MLL2 methyltransferase complex and enhances H3K4 di- and tri-methylation. We also show that PASK is a histone kinase that phosphorylates H3 at T3, T6, S10 and T11. Taken together, these results suggest that PASK regulates two different H3 tail modifications involving H3K4 methylation and H3 phosphorylation. Using muscle satellite cell differentiation and functional analysis after loss or gain of Pask expression using the CRISPR/Cas9 system, we provide evidence that some of the regulatory functions of PASK during development and differentiation may occur through the regulation of these histone modifications., (© The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Introduction : More than 424 million adults have diabetes mellitus (DM). This number is expected to increase to 626 million by 2045. The majority (90-95%) of people with DM has type 2-diabetes (T2DM). The continued prevalence of DM and associated complications has prompted investigators to find new therapies. One of the most recent additions to the anti-diabetic armamentarium are inhibitors of sodium-glucose co-transporters 1 and 2 (SGLT1, SGLT2). Areas covered : The authors review the status of SGLT2 inhibitors for the treatment of T2DM and place an emphasis on those agents in early phase clinical trials. Data and information were retrieved from American Diabetes Association, Diabetes UK, ClinicalTrials.gov, PubMed, and Scopus websites. The keywords used in the search were T2DM, SGLT1, SGLT2, and clinical trials. Expert opinion : The benefits of SGLT inhibitors include reductions in serum glycated hemoglobin (HbA1c), body weight, blood pressure and cardiovascular and renal events. However, SGLT inhibitors increase the risk of genitourinary tract infections, diabetic ketoacidosis, and bone fractures. The development of SGLT inhibitors with fewer side effects and as combination therapies are the key to maximizing the therapeutic effects of this important class of anti-diabetic drug.

Inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn's disease are characterized by chronic inflammation of the gastrointestinal system. There is no permanent cure from IBD except constant medication or surgery to keep the disease in remission. In the present study, the effect of menthol, a major ingredient of peppermint has been investigated in acetic acid-induced colitis model in Wistar rats. Menthol (50 mg/kg/day) was orally administered for either 3 days before or 30 min after IBD induction for 7 days. The changes in body weight, macroscopic and microscopic analysis of the colon of rats of different experimental groups were observed on day 0, 2, 4 and 7. Acetic acid caused a significant reduction in mean body weight and induced macroscopic and microscopic ulceration along with a significant decline of glutathione (GSH) levels, an antioxidant substrate concomitant to increased malondialdehyde (MDA) level, a marker of lipid peroxidation and raised myeloperoxidase (MPO) activity, itself a marker for neutrophil activation. Acetic acid also induced the release of pro-inflammatory cytokines. Furthermore, acetic acid also raised the levels of calprotectin, a protein released by neutrophils under inflammatory conditions of the gastrointestinal tract. Treatment with menthol significantly improved IBD-induced reduction in mean body weight and mean macroscopic and microscopic ulcer scores and reduced activities of MPO and levels of MDA with concomitant increase in GSH level. Additionally, menthol treatment significantly reduced the levels of pro-inflammatory cytokines such as interleukin-1, interleukin-23 and tumor necrosis factor-α with no significant change in interleukin-6 levels. The data indicate that menthol improved body weight gain, mean macroscopic and microscopic ulcer scores, attenuated lipid peroxidation, oxidative stress and inflammation in the IBD rat mucosa., Competing Interests: None.

There is much evidence that diabetes mellitus (DM)-induced hyperglycemia (HG) is responsible for kidney failure or nephropathy leading to cardiovascular complications. Cellular and molecular mechanism(s) whereby DM can damage the kidney is still not fully understood. This study investigated the effect of streptozotocin (STZ)-induced diabetes (T1DM) on the structure and associated molecular alterations of the isolated rat left kidney following 2 and 4 months of the disorder compared to the respective age-matched controls. The results revealed hypertrophy and general disorganized architecture of the kidney characterized by expansion in glomerular borders, tubular atrophy and increased vacuolization of renal tubular epithelial cells in the diabetic groups compared to controls. Electron microscopic analysis revealed ultrastructural alterations in the left kidney highlighted by an increase in glomerular basement membrane width. In addition, increased caspase-3 immunoreactivity was observed in the kidney of T1DM animals compared to age-matched controls. These structural changes were associated with elevated extracellular matrix (ECM) deposition and consequently, altered gene expression profile of ECM key components, together with elevated levels of key mediators (MMP9, integrin 5α, TIMP4, CTGF, vimentin) and reduced expressions of Cx43 and MMP2 of the ECM. Marked hypertrophy of the kidney was highlighted by increased atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) gene expression. These changes also correlated with increased TGFβ1 activity, gene expression in the left kidney and elevated active TGFβ1 in the plasma of T1DM rats compared to control. The results clearly demonstrated that TIDM could elicit severe structural changes and alteration in biochemical markers (remodelling) in the kidney leading to diabetic nephropathy (DN).

Nociceptin (NC), also known as Orphanin FQ, is a brain peptide involved in the regulation of pain, but its role in the endocrine pancreas is poorly understood. The present study examines the pattern of distribution of NC and its effect on insulin and glucagon secretion after the onset of diabetes mellitus (DM). Male Wistar rats weighing 150-200 g were made diabetic with streptozotocin (60 mg/kg body weight, intraperitoneally). Four weeks after the induction of DM, pancreatic tissues were retrieved and processed for immunofluorescence, immunoelectron microscopy, and insulin and glucagon secretion. Isolated islets from non-diabetic and diabetic rats were used to determine the effect of NC on insulin release. NC was discerned in islet cells of non-diabetic control and diabetic rat pancreata. NC co-localized only with insulin in pancreatic beta cells. NC did not co-localize with either glucagon or somatostatin or pancreatic polypeptide. The number of NC-positive cells was markedly (p < 0.001) reduced after the onset of DM. Electron microscopy study showed that NC is located with insulin in the same secretory granules of the beta cells of both non-diabetic and diabetic rat pancreas. NC inhibits insulin release markedly (p < 0.05) from pancreatic tissue fragments of non-diabetic and diabetic rats. In contrast, NC at 10 -12  M stimulates insulin release in isolated islets of DM rats. In conclusion, NC co-localizes with insulin only in the islet of Langerhans. The co-localization of NC with insulin suggests a role for NC in the regulation of pancreatic beta cell function.

The development of a diabetic cardiomyopathy is a multifactorial process, and evidence is accumulating that defects in intracellular free calcium concentration [Ca 2+ ] i or its homeostasis are related to impaired mechanical performance of the diabetic heart leading to a reduction in contractile dysfunction. Defects in ryanodine receptor, reduced activity of the sarcoplasmic reticulum calcium pump (SERCA) and, along with reduced activity of the sodium-calcium exchanger (NCX) and alterations in myofilament, collectively cause a calcium imbalance within the diabetic cardiomyocytes. This in turn is characterized by cytosolic calcium overloading or elevated diastolic calcium leading to heart failure. Numerous studies have been performed to identify the cellular, subcellular, and molecular derangements in diabetes-induced cardiomyopathy (DCM), but the precise mechanism(s) is still unknown. This review focuses on the mechanism behind DCM, the onset of contractile dysfunction, and the associated changes with special emphasis on hyperglycemia, mitochondrial dysfunction in the diabetic heart. Further, management strategies, including treatment and emerging therapeutic modalities, are discussed.

Background: Selegiline [(-)-deprenyl] is widely used for the treatment of Parkinson's disease in humans., Objective: Time-dependence of tissue distribution of selegiline following per os administration to rats., Method: Oral administration of radiolabeled selegiline to rats resulted in a pattern of tissue distribution similar to that following intraperitoneal injection. Analyses were done using both reversed-phase HPLC and also by counting radioactivity in various body compartments of rats., Results: As a consequence of oral administration of 30 mg/kg of selegiline, its level in the stomach was extremely high (179.57 µg/g tissue through 54.67 µg/g at 15 min to 120 min), that is one magnitude higher than that in the serum level. High selegiline concentrations were also detected in the lacrimal glands (7.45 µg/g), kidneys (6.87 µg/g), livers (6.01 µg/g) and lungs (3.47 µg/g) after 30 minutes of application, which were higher than after intraperitoneal injections., Conclusion: The relatively high tissue levels remained for 120 min monitoring. Selegiline levels in the brain (1.69 µg/g) and in the testes (1.88 µg/g) were also considerably higher than following intraperitoneal administration during the entire period of observation (15 to 120 min).

Introduction: Diabetes mellitus (DM) is a major metabolic disorder currently affecting over 350 million people worldwide. Also, another one billion people in the world are pre-diabetic, who may eventually end up with full- blown diabetes. It costs around 1,200 billion USD to diagnose, treat and care for both type 1 DM (T1DM) and type 2 DM (T2DM) patients globally. The disorder is rapidly increasing out of proportion in both developed and developing countries, especially T2DM, which is associated with modern lifestyle habits such as reduced physical activity, diet, obesity and genetic factors. If left untreated, DM can lead to a number of diseases and long-term complications leading subsequently to death. Areas Covered: In this mini review, we aim to highlight a number of complications, cascades or pathways (polyol, hexosamine, protein kinase C, advanced glycation-end product) of events and cellular, sub-cellular and molecular mechanisms associated with DM-induced hyperglycaemia (HG)., Conclusion: Chronic complications of DM are caused largely by HG-induced cellular and molecular impairment of neural and vascular structure and function. HG-induced oxidative stress is a major contributor in the development of long-term complications of DM. DM-induced neuropathy and angiopathy, in turn, may lead to the dysfunction of cells, tissues and organ systems., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

The prevalence of diabetes mellitus (DM) is about 6% across the globe. This prevalence has been reported to increase in the near future. This means that the number of women with DM who would like to get pregnant and have children will also increase. The present study is aimed at investigating the morphological changes observed in the uterus after the onset of DM. The study also examined the pattern of distribution of nociceptin (NC), a neuropeptide involved in the regulation of pain, a major physiological factor during parturition. The study shows a severe atrophy of uteri as early as 15 days post DM and continued until the termination of the eight-week study. This atrophy was confirmed by light microscopy. Electron microscopy study showed atrophy of the columnar cells of the endometrium, reduced myofibril number and destruction of smooth muscle cells in the myometrium of diabetic rats compared to control. Immunofluorescence and immunoelectron microscopy studies clearly demonstrated the presence of NC in the endometrium, myometrium and on the myofibrils of the smooth muscles of both control and diabetic rat uteri. In addition, NC-positive neurons and varicose fibres were observed in the myometrium of both normal and diabetic rats. However, the expression of NC decreased after the onset of DM. Morphometric analysis showed that the number of NC-labeled cells was significantly (p < 0.05) lower in diabetic rat uteri compared to those of control. In conclusion, DM-induced uterine atrophy is associated with a decrease in the expression of NC in cells, neurons and myofibrils of the rat uterus.

Glucagon-like peptide 1 (GLP1) agonists are promising therapeutic agents in the treatment of diabetes mellitus. This study examines the mechanism of the protective effects of exenatide in experimental diabetes, employing four groups of ten rats each, in which two groups were streptozotocin-induced diabetic and two were control groups. One control and one diabetic group were treated with exenatide (1 μg/kg body weight (BW)) for 10 weeks. Blood plasma was taken for biochemical analyses while pancreatic tissue was taken for immunofluorescence and immunoelectron microscopy studies and real-time PCR to examine the expression of genes. The results show that exenatide improved BW gain and reduced blood glucose in diabetic rats compared with controls. Similarly, exenatide enhanced insulin release from the pancreatic fragments and improved liver and kidney functions and lipid profile in diabetic rats compared with controls. Exenatide not only induced significant increases in serum insulin level but also elevated the number of insulin-, GLP1- and exenatide-positive cells compared with untreated controls. Exenatide also elevated the number of catalase- and glutathione reductase-positive cells in diabetic rat pancreas compared with controls. Exenatide caused significant elevation in the expressions of pancreatic duodenal homeobox-1, heat shock protein-70, glutathione peroxidase, insulin receptor and GLP1 receptor genes in the pancreas of both control and diabetic rats compared with untreated animals. The results have demonstrated that exenatide can exert its beneficial and protective effects by elevating the levels of endogenous antioxidants and genes responsible for the survival, regeneration and proliferation of pancreatic β-cell.

Diabetes mellitus (DM) is a major metabolic disorder currently affecting over 250 million people globally. It costs the worldwide health services almost £800 billion annually to diagnose, treat and care for patients with diabetes. DM is predicted to rise to 350 million by 2030. If left unmanaged, DM can lead to numerous long-term complications including micro- and macro-angiopathy and heart failure (HF). Most diabetics usually die as a result of HF resulting from diabetes-induced coronary artery disease and cardiomyopathy. Coronary artery disease and cardiomyopathy are normally preceded by hyperglycaemia (HG). This review examines the structural changes, which occur within the myocardium and cardiomyocytes during exposure of the heart to diabetes-induced HG and HG-induced oxidative stress. HG and the resulting oxidative stress are associated with marked myocardial hypertrophy and fibrosis compared to control heart. At the ultrastructural level, cardiomyocytes subjected to chronic HG and subsequent oxidative stress display swollen mitochondria, reduced mitochondrial number and defective myofibrils and intercalated discs. Evidence from many studies shows that both type 1 and type 2 diabetes-induced HG can cause myocardial fibrosis, mitochondriopathy, myocyte hypertrophy and deranged myofibrils. All of these structural changes may eventually result in HF if left untreated.