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• The current study details adaptation and validation of the Driving Behaviour Scale. • The study was conducted in Poland employing a non-clinical sample of drivers. • The scale may be utilised as a measure of driving anxiety in the general population. • The findings will add to the research on the psychometric properties of the scale. Anxiety can negatively affect an individual's psychological wellbeing and lead to mild-to-moderate functional impairment in various areas of their lives. Despite this, the relationship between anxiety and driving performance has received very little empirical attention. The Driving Behaviour Scale (Clapp, Olsen, Beck, et al., 2011, Clapp, Olsen, Danoff-Burg, et al., 2011) was developed as a measure of anxious driving behaviours to support research in this area. The current study details adaptation and validation of the Driving Behaviour Scale (DBS; Clapp, Olsen, Beck, et al., 2011, Clapp, Olsen, Danoff-Burg, et al., 2011) in 310 university students in Poland. The overall internal consistency for the DBS was 0.76, while the two subscales demonstrated acceptable internal consistency (safety/cautious = 0.75 and hostile/aggressive behaviours = 0.85). The reliability estimates for performance deficit returned a lower coefficient of 0.65. Factor analysis produced a three-factor solution that supported the original structure of the DBS. The DBS may be utilised as a measure of driving anxiety in samples drawn from the general population. [ABSTRACT FROM AUTHOR]

Background: Richter transformation (RT) is the development of aggressive lymphoma in patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). This rare disease is characterised by dismal prognosis. In recent years, there has been a deeper understanding of RT molecular pathogenesis, and disruptions of apoptosis (TP53) and proliferation (CDKN2A, MYC, NOTCH1) has been described as typical aberrations in RT. Results: A single-institution cohort of 33 RT patients were investigated by karyotyping, fluorescence in situ hybridization and single nucleotide polymorphism/copy number (CN) arrays. Most of RTs were typically manifested by diffuse large B-cell lymphoma, not otherwise specified, among the remaining cases one was classified as high-grade B-cell lymphoma with 11q aberrations. The most frequent alterations (40–60% of cases) were represented by MYC rearrangement/gain, deletions of TP53 and CDKN2A, IGH rearrangement and 13q14 deletion. Several other frequent lesions included losses of 14q24.1-q32.33, 7q31.33-q36.3, and gain of 5q35.2. Analysis of 13 CLL/SLL-RT pairs showed that RT arised from the CLL/SLL by acquiring of 10 ~ 12 cytogenetic or CN lesions/case, but without acquisition of loss of heterozygosity regions. Our result affirmed the higher genetic complexity in RT than CLL/SLL and confirmed the linear features of RT clonal evolution as predominant. Conclusions: Cytogenomic profile was concordant with the literature data, however the role of IGH rearrangement, 14q deletion and 5q35.2 gain need to be explored. We anticipate that further characterization of RT lesions will probably facilitate better understanding of the RT clonal evolution. [ABSTRACT FROM AUTHOR]

Ceramides have been shown to play a major role in the onset of skeletal muscle insulin resistance and therefore in the prevalence of type 2 diabetes. However, many of the studies involved in the discovery of deleterious ceramide actions used a nonphysiological, cell-permeable, short-chain ceramide analog, the C2-ceramide (C2-cer). In the present study, we determined how C2-cer promotes insulin resistance in muscle cells. We demonstrate that C2-cer enters the salvage/recycling pathway and becomes deacylated, yielding sphingosine, re-acylation of which depends on the availability of long chain fatty acids provided by the lipogenesis pathway in muscle cells. Importantly, we show these salvaged ceramides are actually responsible for the inhibition of insulin signaling induced by C2-cer. Interestingly, we also show that the exogenous and endogenous monounsaturated fatty acid oleate prevents C2-cer to be recycled into endogenous ceramide species in a diacylglycerol O-acyltransferase 1-dependent mechanism, which forces free fatty acid metabolism towards triacylglyceride production. Altogether, the study highlights for the first time that C2-cer induces a loss in insulin sensitivity through the salvage/recycling pathway in muscle cells. This study also validates C2-cer as a convenient tool to decipher mechanisms by which longchain ceramides mediate insulin resistance in muscle cells and suggests that in addition to the de novo ceramide synthesis, recycling of ceramide could contribute to muscle insulin resistance observed in obesity and type 2 diabetes. [ABSTRACT FROM AUTHOR]

Isoniazid (INH), a key agent in the treatment of tuberculosis (TB), is metabolized primarily by the genetically polymorphic N-acetyltransferase 2 (NAT2) enzyme. Patients treated with INH can be classified as fast, intermediate, and slow acetylators. The objective of this study was to explore the relationship between NAT2 genotypes and the serum concentrations of INH. Blood samples from 130 patients were taken for the analysis, and plasma INH concentrations were determined by using the high-performance liquid chromatography (HPLC) technology. Acetylation genotype was determined on genomic DNA by using an allele-specific polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Once the NAT2 genotypes were established, patients were classified into three categories: fast, intermediate, and slow acetylators. Of the 130 patients studied, 84 (64.6%) were slow, 39 (30%) were intermediate, and 7 (5.4%) were fast acetylators. Analysis of INH concentrations in the blood of patients receiving the approximate doses of the drug revealed that, at the time intervals examined, the average concentration of INH was 2- to 7-fold higher among slow acetylators compared to fast and intermediate acetylators. Conclusion. Determining mutations in the NAT2 gene enabled the identification of the INH acetylation type in patients and the genotyping results were consistent with the phenotype determined by methods of measurement of drug bioavailability. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis and structural analysis of mesoporous silica materials with the use of aluminum phyllosilicate clay (bentonite) as an alternative silica source. In the proposed synthesis, bentonite, as natural aluminosilicate, was used instead of commercially available and quite expensive tetraethyl orthosilicate (TEOS) silica source. The objective of the research study was to determine the effect of aluminum loading in the mesoporous silica body for ordering structure, porosity, and potential sorption capacity to thorium ions. The unique direction developed in this procedure is focused on preparing advanced materials from natural sources with their own desired functionality and general availability. The applied procedure based on the classic, one-step synthesis of SBA-15 silicates was modified by gradually increasing the bentonite amount with simultaneous reduction of the TEOS content. The structural and morphological characterization, as well as evaluation of the porous structure of the obtained materials, was performed using powder wide-angle X-ray diffraction (XRD), small-angle scattering (SAXS), transmission and scanning electron microscopy (TEM, SEM), low-temperature nitrogen adsorption–desorption methods and potentiometric titration. The new, cost-effective composites for the removal of Th(IV) ions are proposed. The synergistic effect of expanding the porous surface using bentonite as a silica precursor and the presence of thorium-binding groups (such as Al2O3) is indicated. [ABSTRACT FROM AUTHOR]

Insulin resistance is associated boh with intramuscular lipids and with circulating pro- and atiinflammatory cytokines, like interleukin (IL)-18, visfatin, adiponectin and IL-10. The aim of our study was to estimate the relationships between serum adiponectin, IL- 10, IL-18 and visfatin concentrations and muscle lipid fractious in healthy humans. The study group consisted of 37 male subjects with normal glucose tolerance. Euglycemic hyperinsulinemic clamp and a biopsy of vastus lateralis muscle were performed. Muscle diacylglycerol (DAG), triacylglycerol (TG), ceramide, sphingosine and sphinganine content and the activities of the enzymes: neutral and acid sphingomyelinase, neutral and alkaline ceramidase and serine palmitoyltransferase were measured. Insulin sensitivity was related to circulating cytokines (adiponectin, r=0.38, p=0.021; IL-10, r=0.47, 10=0.0034; IL-18, r=-0.37, p=0.023) and to muscle lipids (ceramide, r=-0.45, p=0.024; DAG, r=-0.43, p=0.031; TG, r=-0.52; p=0.01). It was also associated with the activities of the enzymes regulating ceramide metabolism (serine palmitoyltransferase, r=-0.58, p=0.002; alkaline ceramidase, r=-0.37, p=0.025). Adiponectin and visfatin were related to muscle ceramide content (r=-0.44, p=0.027 and r=0.43, p=0.031, respectively) and to serine palmitoyltransferase activity (r=-0.35, p=0.032 and r=0.49, p=0.032, respectively). IL-10 and IL-18 were associated with muscle DAG (IL-10, r=0.46, p=0.022; IL-18, r=0.40, p=0.049) and muscle TG (IL-10, r=-0.50, p=0.014; IL-18, r=0.46, p=0.026). Our data indicate that there are multiple associations between circulating cytokines and muscle lipid pool, which possibly might influence insulin sensitivity. Adiponectin and visfatin are related to muscle ceramide, whereas IL-10 and IL-18 are associated with muscle DAG and TG content. [ABSTRACT FROM AUTHOR]

(1) Background: Disturbances in the sphingolipid profile are observed in many diseases. There are currently no data available on the evaluation of sphingolipids and ceramides in cholelithiasis in children. The aim of this study was to evaluate the concentrations of sphingolipids in the sera of pediatric patients with gallstones. We determined their relationship with anthropometric and biochemical parameters. (2) Methods: The concentrations of sphingolipids in serum samples were evaluated using a quantitative method, ultra-high-performance liquid chromatography–tandem mass spectrometry. (3) Results: The prospective study included 48 children and adolescents diagnosed with gallstones and 38 controls. Serum concentrations of total cholesterol (TC); sphinganine (SPA); ceramides—C14:0-Cer, C16:0-Cer, C18:1-Cer, C18:0-Cer, C20:0-Cer and C24:1-Cer; and lactosylceramides—C16:0-LacCer, C18:0-LacCer, C18:1-LacCer, C24:0-LacCer and C24:1-LacCer differed significantly between patients with cholelithiasis and without cholelithiasis. After adjusting for age, gender, obesity and TC and TG levels, we found the best differentiating sphingolipids for cholelithiasis in the form of decreased SPA, C14:0-Cer, C16:0-Cer, C24:1-LacCer and C24:0-LacCer concentration and increased C20:0-Cer, C24:1-Cer, C16:0-LacCer and C18:1-LacCer. The highest area under the curve (AUC), specificity and sensitivity were determined for C16:0-Cer with cholelithiasis diagnosis. (4) Conclusions: Our results suggest that serum sphingolipids may be potential biomarkers in pediatric patients with cholelithiasis. [ABSTRACT FROM AUTHOR]

Aim & Methods: Extreme endurance exercise provides a valuable research model for understanding the adaptive metabolic response of older and younger individuals to intense physical activity. Here, we compare a wide range of metabolic and physiologic parameters in two cohorts of seven trained men, age 30 ± 5 years or age 65 ± 6 years, before and after the participants travelled ≈3000 km by bicycle over 15 days. Results: Over the 15‐day exercise intervention, participants lost 2–3 kg fat mass with no significant change in body weight. V̇O2max did not change in younger cyclists, but decreased (p = 0.06) in the older cohort. The resting plasma FFA concentration decreased markedly in both groups, and plasma glucose increased in the younger group. In the older cohort, plasma LDL‐cholesterol and plasma triglyceride decreased. In skeletal muscle, fat transporters CD36 and FABPm remained unchanged. The glucose handling proteins GLUT4 and SNAP23 increased in both groups. Mitochondrial ROS production decreased in both groups, and ADP sensitivity increased in skeletal muscle in the older but not in the younger cohort. Conclusion: In summary, these data suggest that older but not younger individuals experience a negative adaptive response affecting cardiovascular function in response to extreme endurance exercise, while a positive response to the same exercise intervention is observed in peripheral tissues in younger and older men. The results also suggest that the adaptive thresholds differ in younger and old men, and this difference primarily affects central cardiovascular functions in older men after extreme endurance exercise. [ABSTRACT FROM AUTHOR]

The occurrence of MYC-negative Burkitt lymphoma (BL) has been discussed for many years. The real frequency of the MYC insertion in MYC-negative BL is still unknown. Fine-needle aspiration biopsies of 108 consecutive patients with clinicopathologically suspected BL (suspBL) were evaluated by flow cytometry, classical cytogenetics, and fluorescence in situ hybridization (FISH). We found 12 cases (11%) without the MYC rearrangement by FISH with a MYC breakapart probe: two patients (1.9%) with cryptic MYC/IGH fusion (finally diagnosed as BL) and 10 patients (9.3%) with 11q gain/loss (finally diagnosed as Burkitt-like lymphoma with 11q aberration). The exact breakpoints of the cryptic MYC/IGH were investigated by next-generation sequencing. The MYC insertions' breakpoints were identified in PVT1 in the first case, and 42 kb upstream of 5′MYC in the second case. To date, a molecular characterization of the MYC insertion in BL has only been reported in one case. Detailed descriptions of our MYC insertions in a routinely and consecutively diagnosed suspBL cohort will contribute to resolving the issue of MYC negativity in BL. In our opinion, the presence of the MYC insertions in BL and other lymphomas might be underestimated, because routine genetic diagnostics are usually based on FISH only, without karyotyping. [ABSTRACT FROM AUTHOR]

• Burkitt-like lymphoma with 11q aberration occurs in post-transplant patients. • 11q-gain/loss may coexist with MYC amplification in post-transplant patients with Burkitt-like lymphoma with 11q aberration. • The presence of MYC amplification increase the aggressiveness of the disease course. "Burkitt-like lymphoma with 11q aberration" is a new provisional entity in the latest revision of lymphoma's World Health Organization classification described as carrying the specific 11q-gain/loss aberration and lacking MYC rearrangement. Morphologically, phenotypically and by gene and microRNA expression profiling these lymphomas resemble Burkitt lymphoma. The 11q-gain/loss was also found in post-transplant patients with molecular Burkitt lymphoma signature without MYC rearrangement. Recent reports describe aggressive lymphomas with coexistence of 11q-gain/loss and MYC rearrangement. In this report we describe post-transplant Burkitt-like lymphoma with 11q aberration and MYC amplification. Genetic studies were conducted at two time points: before therapy and during progression. In both cytogenetic examinations, peculiar 11q-gain/loss was detected. Percentage of cells carrying MYC amplification increased from 2% at initial diagnosis to 97% during progression. The MYC amplification can functionally correspond to MYC translocation and to MYC overexpression. The presence of MYC amplification seems to increase the aggressiveness of the reported disease course, so even a small clone with this change should be indicated in cytogenetic result. [ABSTRACT FROM AUTHOR]

The worldwide prevalence of metabolic diseases is increasing, and there are global recommendations to limit consumption of certain nutrients, especially saturated lipids. Insulin resistance, a common trait occurring in obesity and type 2 diabetes, is associated with intestinal lipoprotein overproduction. However, the mechanisms by which the intestine develops insulin resistance in response to lipid overload remain unknown. Here, we show that insulin inhibits triglyceride secretion and intestinal microsomal triglyceride transfer protein expression in vivo in healthy mice force-fed monounsaturated fatty acid-rich olive oil but not in mice force-fed saturated fatty acid-rich palm oil. Moreover, when mouse intestine and human Caco-2/TC7 enterocytes were treated with the saturated fatty acid, palmitic acid, the insulinsignaling pathway was impaired. We show that palmitic acid or palm oil increases ceramide production in intestinal cells and that treatment with a ceramide analogue partially reproduces the effects of palmitic acid on insulin signaling. In Caco-2/TC7 enterocytes, ceramide effects on insulin-dependent AKT phosphorylation are mediated by protein kinase C but not by protein phosphatase 2A. Finally, inhibiting de novo ceramide synthesis improves the response of palmitic acid-treated Caco-2/TC7 enterocytes to insulin. These results demonstrate that a palmitic acid-ceramide pathway accounts for impaired intestinal insulin sensitivity, which occurs within several hours following initial lipid exposure. [ABSTRACT FROM AUTHOR]

In vivo, ectopic accumulation of fatty acids in muscles leads to alterations in insulin signaling at both the IRS1 and Akt steps. However, in vitro treatments with saturated fatty acids or their derivative ceramide demonstrate an effect only at the Akt step. In this study, we adapted our experimental procedures to mimic the in vivo situation and show that the double-stranded RNAdependent protein kinase (PKR) is involved in the long-term effects of saturated fatty acids on IRS1. C2C12 or human muscle cells were incubated with palmitate or directly with ceramide for short or long periods, and insulin signaling pathway activity was evaluated. PKR involvement was assessed through pharmacological and genetic studies. Short-term treatments of myotubes with palmitate, a ceramide precursor, or directly with ceramide induce an inhibition of Akt, whereas prolonged periods of treatment show an additive inhibition of insulin signaling through increased IRS1 serine 307 phosphorylation. PKR mRNA, protein, and phosphorylation are increased in insulin-resistant muscles. When PKR activity is reduced (siRNA or a pharmacological inhibitor), serine phosphorylation of IRS1 is reduced, and insulin-induced phosphorylation of Akt is improved. Finally, we show that JNK mediates ceramide-activated PKR inhibitory action on IRS1. Together, in the long term, our results show that ceramide acts at two distinct levels of the insulin signaling pathway (IRS1 and Akt). PKR, which is induced by both inflammation signals and ceramide, could play a major role in the development of insulin resistance in muscle cells. [ABSTRACT FROM AUTHOR]

• Intrahepatic cholestasis related perinatal complications include premature birth, meconium-stained amniotic fluid, fetal bradycardia, fetal respiratory distress syndrome and intrauterine fetal demise. • Cholestasis treatment with UDCA is known to be very effective. • Sphingolipids can potentially become screening markers as well as markers for monitoring the treatment of ICP in pregnant women. Intrahepatic cholestasis of pregnancy (ICP) is the most common pregnancy-related liver disorder that affects from 0.2% to 15.6% pregnant women. The disease is connected with increased risk of fetal morbidity and mortality, but is unfortunately detected quite late. The diagnosis of ICP is based on only one manifestation: pruritus which mainly affects soles and palms. Twenty intrahepatic cholestasis of pregnancy (ICP) women and twenty healthy pregnant women (control group) took part in the study. In the study group, blood sampling for baseline measurements was performed on the first day of hospital stay – before the commencement of treatment with ursodeoxycholic acid (UDCA) – and repeated after 7 days of 900 mg UDCA per day. An additional blood sample was collected on the second day after childbirth. In the control group, blood samples were collected directly after hospital admission. We compared plasma sphingolipids in samples of the subjects from ICP and ICP + UDCA-treated groups as well as the ICP group after delivery with the healthy controls. Of all sphingolipids, the median values of C16-Cer and C18-Cer were significantly higher in the plasma of cholestasis patients not treated with UDCA as compared to the control. Following 7 days of UDCA treatment, a considerable decrease in C16-Cer, C18-Cer and the total concentration of bile acids was noted as compared to the baseline. It is known that sphingolipids serve as modulators of liver regeneration. We assume these substances could be potential markers for detecting early onsets of intrahepatic cholestasis of pregnancy. [ABSTRACT FROM AUTHOR]

Abstract: Transplant recipients are at high risk of fungal infections. The main site of fungal infections in patients undergoing liver transplantation is the abdominal cavity. One factor determining the pathogenicity of fungi is their ability to secrete hydrolytic enzymes. The aim of this study was to assess the enzymatic activity of Candida krusei, which caused an infection in a liver transplant recipient. The clinical specimens included swabs of throat, nose, and two drains, as well as bile, stool, and abdominal cavity aspirate. The yeast-like fungi isolated were identified by an ID 32 C test (bioMérieux) and their enzymatic activity assayed with the use of an API-ZYM test. Two biotypes of C. krusei were identified, depending on the source of the clinical specimen. The C. krusei isolates cultured from a throat swab, a nasal swab, and one of the drains secreted esterase lipase C8 (enzyme IV) and valine arylamidase (enzyme VII), in contrast to those isolated from the bile, abdominal cavity fluid, another drain, and stool. Characterization of two biotypes of C. krusei isolates cultured from different clinical samples from several infection sites indicated an ability of C. krusei to adapt to variable environmental conditions. [Copyright &y& Elsevier]

Objective: To investigate the relationships between dental anxiety, Facebook intrusion, and shame., Methods: A sample of 498 adults aged 16-69 years completed an online questionnaire comprising the Modified Dental Anxiety Scale, the Facebook Intrusion Scale, and the Shame scale from the Test of Self-Conscious Affect., Results: Dental anxiety was positively associated with Facebook intrusion. There were also indirect effects of dental anxiety on Facebook intrusion through shame., Conclusions: The results highlight the problem of dental anxiety in the context of Facebook intrusion risk. The findings may be applicable in Internet dependency prevention and treatment, focused on help in coping with the anxiety related to doctors' appointments., (Copyright© 2022 Dennis Barber Ltd.)

Introduction and Objective: Epidemiological studies have demonstrated a strong association between cigarette smoking (CS) and chronic pancreatitis (CP); however, the exact mechanisms of this phenomenon remains unknown. The authors have previously shown that increased Ras expression activates the NF-κB mediated pathway and promotes development of CP. However, it is unclear whether a similar phenomenon occurs in CS-induced CP. Therefore, the aim of the study was to determine whether CS increases the expression of K-Ras, and promotes the development of CP in mice exposed to repeated episodes of acute pancreatitis (AP)., Material and Methods: C57BL6/cmdb mice were exposed to CS or a sham treatment for 12 weeks. After one week of exposure, half of the animals from both groups were additionally subjected to repeated cerulein treatment (once a week, for 10 consecutive weeks) to mimic recurrent episodes of AP. Extension of pancreatic damage was determined histologically by H&E and Trichrome staining. The expression of K-Ras protein and downstream components (NF-κB, Cox-2, TGF-β) was evaluated by immunohistochemistry., Results: C57BL6/cmdb mice exposed to CS or cerulein alone did not develop any chronic pancreatic damage. However, concomitant treatment with both of these agents caused focal acinar atrophy, with slight intralobular and perivascular areas of fibrosis, and inflammatory cells infiltration resembling mild CP. Moreover, immunohistochemistry examinations revealed increased pancreatic expression of K-Ras and NF-κB only in mice treated both with CS and cerulein., Conclusions: CS promotes development of CP in mice exposed to repeated episodes of AP. This process may be, at least partially, related to increased expression of K-Ras and NF-κB protein.

With the increase in the popularity of the Internet, more and more of its users are becoming addicted to it. Special focus in this study is placed on adolescents and emerging adults who constitute the largest number of users in Poland. The participants in the study were 718 individuals aged 12 to 30 (M = 17.57, SD = 3.63). There were two groups: 390 adolescents (aged 12-17 years, M = 14.71 years, SD = 0.99; 192 females) and 328 emerging adults (aged 18-30 years, M = 20.96 years, SD = 2.54; 197 females). The respondents completed: the Polish versions of Young's Internet Addiction Test (IAT), the Center for Epidemiologic Studies Depression Scale (CES-D), the IPIP-BFM-20 questionnaire measuring the Big Five, and the Future Time Perspective Questionnaire. The results showed that depression had the highest predictive power for IA. Personality traits were related to Internet addiction. In both groups, conscientiousness and agreeableness had negative contribution to Internet addiction. In the group of adolescents extraversion was a positive predictor of IA, whereas in emerging adults intellect was a negative predictor of IA. FTP long and FTP goals were predictors of IA in the group of emerging adults., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Ozonated blood therapy is used in the treatment of several diseases, including superficial infections, burns, dental and intestinal conditions. Except that, the possibility of using ozone to sterilize blood supplies is under promising investigation. However, still little is known regarding the impact of blood ozonation, especially on biologically active serum sphinoglipids. In the present work we sought to investigate the contents of sphingolipids, such as sphingosine, sphingosine-1-phosphate (S-1-P), sphinganine, and ceramide (CER) in the plasma, after immediate and prolonged (1 h) ozonation of human whole blood. For the measurements liquid chromatography hyphenated with the mass spectrometry was applied. We demonstrated that only the content of sphingosine-1-phosphate in the plasma was increased significantly, possibly exerting its beneficial effect for various physiological and clinical events.

Insulin deprivation in type 1 diabetes (T1D) individuals increases lipolysis and plasma free fatty acids (FFA) concentration, which can stimulate synthesis of intramyocellular bioactive lipids such as ceramides (Cer) and long-chain fatty acid-CoAs (LCFa-CoAs). Ceramide was shown to decrease muscle insulin sensitivity, and at mitochondrial levels it stimulates reactive oxygen species production. Here, we show that insulin deprivation in streptozotocin diabetic C57BL/6 mice increases quadriceps muscle Cer content, which was correlated with a concomitant decrease in the body fat and increased plasma FFA, glycosylated hemoglobin level (%Hb A1c), and muscular LCFa-CoA content. The alternations were accompanied by an increase in protein expression in LCFa-CoA and Cer synthesis (FATP1/ACSVL5, CerS1, CerS5), a decrease in the expression of genes implicated in muscle insulin sensitivity (GLUT4, GYS1), and inhibition of insulin signaling cascade by Aktα and GYS3β phosphorylation under acute insulin stimulation. Both the content and composition of sarcoplasmic fraction sphingolipids were most affected by insulin deprivation, whereas mitochondrial fraction sphingolipids remained stable. The observed effects of insulin deprivation were reversed, except for content and composition of LCFa-CoA, CerS protein expression, GYS1 gene expression, and phosphorylation status of Akt and GYS3β when exogenous insulin was provided by subcutaneous insulin implants. Principal component analysis and Pearson's correlation analysis revealed close relationships between the features of the diabetic phenotype, the content of LCFa-CoAs and Cers containing C18-fatty acids in sarcoplasm, but not in mitochondria. Insulin replacement did not completely rescue the phenotype, especially regarding the content of LCFa-CoA, or proteins implicated in Cer synthesis and muscle insulin sensitivity. These persistent changes might contribute to muscle insulin resistance observed in T1D individuals.

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) enhance insulin sensitivity and glucose homeostasis in rodent models of insulin resistance. These beneficial effects have been linked with anti-inflammatory properties, but emerging data suggest that the mechanisms may also converge on mitochondria. We evaluated the influence of dietary n-3 PUFAs on mitochondrial physiology and muscle lipid metabolites in the context of high-fat diet (HFD) in mice. Mice were fed control diets (10% fat), HFD (60% fat), or HFD with fish oil (HFD+FO, 3.4% kcal from n-3 PUFAs) for 10 wk. Body mass and fat mass increased similarly in HFD and HFD+FO, but n-3 PUFAs attenuated the glucose intolerance that developed with HFD and increased expression of genes that regulate glucose metabolism in skeletal muscle. Despite similar muscle triglyceride levels in HFD and HFD+FO, long-chain acyl-CoAs and ceramides were lower in the presence of fish oil. Mitochondrial abundance and oxidative capacity were similarly increased in HFD and HFD+FO compared with controls. Hydrogen peroxide production was similarly elevated in HFD and HFD+FO in isolated mitochondria but not in permeabilized muscle fibers, likely due to increased activity and expression of catalase. These results support a hypothesis that n-3 PUFAs protect glucose tolerance, in part by preventing the accumulation of bioactive lipid mediators that interfere with insulin action. Furthermore, the respiratory function of skeletal muscle mitochondria does not appear to be a major factor in sphingolipid accumulation, glucose intolerance, or the protective effects of n-3 PUFAs.

Peroxisome proliferator-activated receptor alpha (PPARalpha) plays a crucial role in the transcriptional regulation of myocardial lipid metabolism. In vitro studies on isolated cardiomyocytes showed that PPARalpha activation induces expression of numerous genes involved in virtually all steps of fatty acid catabolism. However, there is very few data on the effect of PPARalpha activation on the content and composition of myocardial lipids in vivo. Therefore, our main aim was to examine effects of selective PPARalpha agonist WY-14643 on the content and fatty acid composition of major lipid classes in the heart of rats fed a standard chow (STD) or a high-fat diet (HFD). In STD rats WY-14643 paradoxically decreased palmitate oxidation rate in the heart, however, in HFD animals such effect was not observed. WY-14643 markedly reduced myocardial free fatty acid and diacylglycerol content in STD rats, whereas in HFD group the opposite effect was observed. These changes reflected alterations in plasma lipid concentration which suggests that effects of WY-14643 on the heart were indirect and secondary to changes in plasma lipid availability induced by the drug. Basal myocardial glucose uptake was not affected by PPARalpha agonist in either group, however, glycogen content in the heart was markedly increased. WY-14643 exerted profound influence on the fatty acid composition of myocardial phospholipids in both diet groups. These changes included increased percentage of monounsaturated fatty acids and replacement of n-3 polyunsaturated fatty acids (PUFA) by those from the n-6 family. This action of WY-14643 might be detrimental to the heart since n-3 PUFA possess cardioprotective and antiarrhythmic properties.