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Introduction: The aim of this study was to evaluate the efficacy and safety of initial combination therapy compared with monotherapy in drug-naïve type 2 diabetes patients.Methods: MEDLINE, Embase and the Cochrane Central Register of Controlled Trials were searched for randomized clinical trials of initial combination therapy with hypoglycemic agents compared with monotherapy. Those which satisfied the search criteria were included in the meta-analysis. Weighted mean difference and relative risks were calculated.Results: A total of 36 studies were included in the meta-analysis. Compared with metformin monotherapy, initial combination therapy with metformin plus another anti-diabetes drug exhibited significant reductions in glycated hemoglobin (HbA1c) (p < 0.001). Most of the combination therapies had a similar risk of hypoglycemia (p > 0.05), with the exception of combinations of sulfonylurea/glinide and metformin or combinations of thiazolidinedione and metformin. Compared with dipeptidyl peptidase-4 (DPP-4) inhibitor monotherapy, initial combination therapy with DPP-4 inhibitor plus another anti-diabetes drug showed a significant decrease in HbA1c (p < 0.001) and a similar risk of hypoglycemia (p > 0.05). Compared with monotherapy with other anti-diabetes drugs, initial combination therapies also resulted in significant HbA1c reductions, a similar risk of hypoglycemia and similar risks of other adverse events.Conclusion: Compared with monotherapy, all initial combination therapies resulted in significant HbA1c reductions. Compared with metformin monotherapy, initial combination therapies with DPP-4 inhibitors plus metformin, sodium/glucose cotransporter 2 inhibitors and metformin, respectively, were associated with similar risks of hypoglycemia, but initial combination therapies with sulfonylurea plus metformin, thiazolidinedione and metformin, respectively, were associated with higher risks of hypoglycemia.Funding: AstraZeneca Ltd. (China).Trial registration: Registration number CRD42017060717 in PROSPERO. [ABSTRACT FROM AUTHOR]

Despite advances in insulin therapies, patients with type 1 diabetes (T1DM) have a shorter life span due to hyperglycaemia-induced vascular disease and hypoglycaemic complications secondary to insulin therapy. Restricting therapy for T1DM to insulin replacement is perhaps an over-simplistic approach, and we focus in this work on reviewing the role of adjuvant therapy in this population. Current data suggest that adding metformin to insulin therapy in T1DM temporarily lowers HbA1c and reduces weight and insulin requirements, but this treatment fails to show a longer-term glycaemic benefit. Agents in the sodium glucose co-transporter-2 inhibitor (SGLT-2) class demonstrate the greatest promise in correcting hyperglycaemia, but there are safety concerns in relation to the risk of diabetic ketoacidosis. Glucagon-like peptide-1 agonists (GLP-1) show a modest effect on glycaemia, if any, but significantly reduce weight, which may make them suitable for use in overweight T1DM patients. Treatment with pramlintide is not widely available worldwide, although there is evidence to indicate that this agent reduces both HbA1c and weight in T1DM. A criticism of adjuvant studies is the heavy reliance on HbA1c as the primary endpoint while generally ignoring other glycaemic parameters. Moreover, vascular risk markers and measures of insulin resistance—important considerations in individuals with a longer T1DM duration—are yet to be fully investigated following adjuvant therapies. Finally, studies to date have made the assumption that T1DM patients are a homogeneous group of individuals who respond similarly to adjuvant therapies, which is unlikely to be the case. Future longer-term adjuvant studies investigating different glycaemic parameters, surrogate vascular markers and harder clinical outcomes will refine our understanding of the roles of such therapies in various subgroups of T1DM patients. [ABSTRACT FROM AUTHOR]

Abstract: This article, co-authored by a patient living with type 2 diabetes and a diabetes specialist physician, discusses the patient's experience of living with type 2 diabetes, including their experience of diagnosis and self-management, education and adoption of SGLT2 inhibitors to treat the disease. The physician discusses the therapeutic challenges of SGLT2 inhibitors and the importance of education.Funding: Napp Pharmaceuticals, Ltd. [ABSTRACT FROM AUTHOR]

CMPF (2-(2-carboxyethyl)-4-methyl-5-propylfuran-3-carboxylic acid) is a metabolite that circulates at high concentrations in type 2 and gestational diabetes patients. Further, human clinical studies suggest it might have a causal role in these diseases. CMPF inhibits insulin secretion in mouse and human islets in vitro and in vivo in rodents. However, the metabolic fate of CMPF and the relationship of structure to effects on insulin secretion have not been significantly studied. The syntheses of CMPF and analogues are described. These include isotopically labeled molecules. Study of these materials in vivo has led to the first observation of a metabolite of CMPF. In addition, a wide range of CMPF analogues have been prepared and characterized in insulin secretion assays using both mouse and human islets. Several molecules that influence insulin secretion in vitro were identified. The molecules described should serve as interesting probes to further study the biology of CMPF. [ABSTRACT FROM AUTHOR]

Rationale Although crude Amaryllidaceae alkaloids (AAs) extracted from Lycoris radiata are reported to exhibit significant anti-cancer activity, both the specific responsible alkaloid(s) and their targets remain elusive. Screening anti-cancer AAs targeted on topoisomerase I from crude AAs could be very helpful in tackling these two challenging questions. Methods An ultrafiltration method combined with liquid chromatography/electrospray ionization mass spectrometry (UF-LC/MS) was developed to screen for the inhibitors of topoisomerase I, which has been reported to mediate DNA unwinding during carcinoma proliferation. Enrichment factors (EFs) of different AAs were used to evaluate the binding affinity between AAs and topoisomerase I, and the AAs with higher EFs were further tested to validate the method. Results Eleven AAs from Lycoris radiata (ten of which were identified) were screened using UF-LC/MS, and a glaring discrepancy in EFs was revealed for the first time. One of the AAs, hippeastrine, with the highest EF at 49.3%, was further tested against topoisomerase I, and the IC50 value of hippeastrine was determined to be 23.0 μmol/L, which is comparable with the well-known anti-cancer drug camptothecin at 19.3 μmol/L. Conclusions A simple, rapid and effective screening method using UF-LC/MS was developed and successfully applied to screen candidate inhibitors of topoisomerase I from crude AAs in Lycoris radiata, which may pave the way to further understand the potential anti-cancer constituents and mechanisms of Lycoris radiata . Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of renal impairment ( RI) and haemodialysis ( HD) on the pharmacokinetics of gemigliptin, a novel dipeptidyl peptidase-4 ( DPP-4) inhibitor. After a 100 mg administration to subjects with normal renal function (n = 23) or RI (n = 24), plasma, urine or dialysate samples were analysed. Control subjects were matched to patients based on age, gender and body mass index. Patients with mild, moderate, severe RI and end-stage renal disease ( ESRD) showed 1.20, 2.04, 1.50 and 1.66-fold (1.10, 1.49, 1.22 and 1.21-fold) increase of mean area under the time-plasma concentration curve from 0 to infinity (AUCinf) [maximum plasma concentration (Cmax)] of gemigliptin, respectively. Pharmacokinetics of gemigliptin was comparable between HD and non- HD periods in ESRD patients. Less than 4% of the dose was removed by 4 h HD. RI appeared to have modest effect on the gemigliptin disposition. No dose adjustment in patients with RI is proposed on the basis of exposure-response relationship. Impact of HD on the removal of gemigliptin was negligible. [ABSTRACT FROM AUTHOR]

Aim To evaluate the efficacy and safety of the dipeptidyl peptidase-4 inhibitor alogliptin plus metformin (A + M) initial combination therapy versus either as monotherapy in drug-naïve T2DM patients. Methods This international, randomized, double-blind, placebo-controlled, 26-week study involved T2DM patients with hyperglycaemia ( HbA1c 7.5-10.0%) following diet/exercise therapy. Patients (N = 784) received placebo, alogliptin (A, 12.5 mg BID or 25 mg QD), metformin (M, 500 or 1000 mg BID) or A + M (12.5/500 or 12.5/1000 mg BID); placebo, A25 for secondary analyses only. Endpoints: week 26 changes from baseline in HbA1c (primary), fasting plasma glucose ( FPG) and 2-h postprandial glucose ( PPG); incidences of clinical response and hyperglycaemic rescue. Results Week 26 mean HbA1c reductions from baseline (8.45%) were −1.22 and −1.55% with A + M 12.5/500 and 12.5/1000 versus −0.56, −0.65, and −1.11% with A12.5, M500 and M1000 (p<0.001, A + M vs. component monotherapies). FPG reductions were −1.76 and −2.55 mmol/L with 12.5/500 and 12.5/1000 versus −0.54, −0.64 and −1.78 mmol/L with A12.5, M500 and M1000 (p < 0.05, A + M vs. component monotherapies). Significantly more A + M-treated patients achieved HbA1c < 7% (47.1-59.5% vs. 20.2-34.3% with monotherapy), significantly fewer required hyperglycaemic rescue (2.6-12.3% vs. 10.8-22.9% with monotherapy). A + M caused only mild/moderate hypoglycaemia (1.9-5.3%) and weight loss (0.6-1.2 kg). Conclusions Alogliptin plus metformin initial combination therapy was well tolerated yet more efficacious in controlling glycaemia in drug-naïve T2DM patients than either as monotherapy. [ABSTRACT FROM AUTHOR]

The article presents study that discusses the impact in hyperoxia on glucotoxicity-induced inhibition of insulin secretion of INS-1β cells in rats. The study examines whether chronic high glucose (CHG) induces cellular hypoxia in rat INS-1&#946 cells and whether hyperoxia reverse glucotoxicity-induced inhibition of insulin secretion. It states that CHG increased intracellular pimonidazole-protein adducts as marker for hypoxia.

The authors reflect on a study by B. Hibbert and colleagues on the potency of glycogen synthase kinase-3β (GSK3β) inhibitors on diabetic patients' endothelial progenitor cells (D-EPCs). They cite the need for revascularization through surgery and endovascular to reestablish tissue function and intromission. They also discuss the study's emphasis on the function of cathepsin B enzymatic protein in GSK3β-intervened regulation of EPC dysfunction in diabetic patients.

The HIV epidemic continues unabated, with no highly effective vaccine and no cure. Each new infection has significant economic, social and human costs and prevention efforts are now as great a priority as global antiretroviral therapy (ART) scale up. Reverse transcriptase inhibitors, the first licensed class of ART, have been at the forefront of treatment and prevention of mother to child transmission over the past two decades. Now, their use in adult prevention is being extensively investigated. We describe two approaches: treatment as prevention (TasP) - the use of combination ART (2NRTI and 1NNRTI) following HIV diagnosis to limit transmission and pre-exposure prophylaxis (PrEP) -the use of single or dual oral agents prior to sexual exposure. Prevention of mother-to-child transmission using NRTI has been highly successful, though does not involve sustained use of NRTI to limit transmission. Despite theoretical and preliminary support for TasP and PrEP, data thus far indicate that adherence, retention in care and late diagnosis are the major barriers to their successful, sustained implementation. Future advances in drug technologies will be needed to overcome the issue of drug adherence, through development of drugs that involve both less frequent dosing as well as reduced toxicity, possibly through specific targeting of infected cells. [ABSTRACT FROM AUTHOR]

The phosphotransferase system (PTS) controls the use of sugars in bacteria. The PTS is ubiquitous in bacteria, but it does not occur in plants and animals; it modulates catabolite repression intermediate metabolism, gene expression, and chemotaxis. Its uniqueness and pleiotropic function make the PTS an attractive target for new antibacterial drugs. The PTS is constituted of two general proteins, namely, enzyme 1 (EI) and the histidine phosphocarrier (HPr), and various sugar-specific permeases. El has two domains: the N-terminal domain (EIN), which binds to HPr, and the C-terminal domain (EIC), which contains the dimerization interface. In this work, we determined the binding affinities of peptides derived from EIN of Streptomyces cnelicolor (EINSC) against HPr of the same organism (HPrSC), by using nuclear magnetic resonance and isothermal titration calorimetry techniques. Purthermore, we measured the affinity of EINSC tor (I) a peptide derived from HPrSC, rnntaining the active-site histidine, and (ii) other peptides identified previously by phage display and combinatorial chemistry in Escherichia coli [Mukhija, S. L., et al (1998) Eur. J. Biochem. 254, 433-438; Mukhija, S., and Erni, B. (1997) Mol. Microbiol. 25, 1159-1168). The affinities were in the range of ~10 μM, being slightly higher for the binding of EINSC with peptides derived from HPrSC, phage display, or combinatorial chemistry (KD ~ 5 μM). Because the affinity of intact EINSC for the whole HPrSC is 12 μM, we suggest that the assayed peptides might be considered as good hit compounds for inhibiting the interaction between HPrSC and EINSC. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To characterize the pharmacodynamic profile of DA-1229, a novel dipeptidyl peptidase (DPP) 4 inhibitor. Main methods: Enzyme inhibition assays against DPP4, DPP8 and DPP9. Antidiabetic effects of DA-1229 in HF-DIO mice and young db/db mice. Key findings: DA-1229 was shown to potently inhibit the DPP4 enzyme in human and murine soluble forms and the human membrane-bound form with IC50 values of 0.98, 3.59 and 1.26nM, respectively. As a reversible and competitive inhibitor, DA-1229 was more selective to human DPP4 (6000-fold) than to human DPP8 and DPP9. DA-1229 (0.1–3mg/kg) dose-dependently inhibited plasma DPP4 activity, leading to increased levels of plasma GLP-1 and insulin, and thereby lowering blood glucose levels in mice. In high fat diet-fed (HF) mice, a single oral dose of 100mg/kg of DA-1229 reduced plasma DPP4 activity by over 80% during a 24h period. Long-term treatment with DA-1229 for 8weeks revealed significant improvements in glucose intolerance and insulin resistance, accompanied by significant body weight reduction. However, it remains unclear whether there is a direct causal relationship between DPP4 inhibition and body weight reduction. In young db/db mice, the DA-1229 treatment significantly reduced blood glucose excursions for the first 2weeks, resulting in significantly lower levels of HbA1c at the end of the study. Furthermore, the pancreatic insulin content of the treatment group was significantly higher than that of the db/db control. Significance: DA-1229 as a novel and selective DPP4 inhibitor improves the insulin sensitivity in HF mice and delays the onset of diabetes in young db/db mice. [Copyright &y& Elsevier]

Ehrlich's pioneering chemotherapeutic experiments published in 1904 (Ehrlich, P., and Shiga, K. (1904) Berlin Klin. Wochenschrift 20, 329-362) described the efficacy of a series of dye molecules including trypan blue and trypan red to eliminate trypanosome infections in mice. The molecular structures of the dyes provided a starting point for the synthesis of suramin, which was developed and used as a trypanocidal drug in 1916 and is still in clinical use. Despite the biological importance of these dye-like molecules, the mode of action on trypanosomes has remained elusive. Here we present crystal structures of suramin and three related dyes in complex with pyruvate kinases from Leishmania mexicana or from Trypanosoma cruzi. The phenyl sulfonate groups of all four molecules (suramin, Ponceau S, acid blue 80, and benzothiazole-2,5-disulfonic acid) bind in the position of ADP/ATP at the active sites of the pyruvate kinases (PYKs). The binding positions in the two different trypanosomatid PYKs are nearly identical. We show that suramin competitively inhibits PYKs from humans (muscle, tumor, and liver isoenzymes, Ki = 1.1-17 ηm), T. cruzi (Ki = 108 ηm), and L. mexicana (Ki = 116 ηm), all of which have similar active sites. Synergistic effects were observed when examining suramin inhibition in the presence of an allosteric effector molecule, whereby IC50 values decreased up to 2-fold for both trypanosomatid and human PYKs. These kinetic and structural analyses provide insight into the promiscuous inhibition observed for suramin and into the mode of action of the dye-like molecules used in Ehrlich's original experiments. [ABSTRACT FROM AUTHOR]

The NaCl cotransporter (NCC) is essential for sodium reabsorption at the distal convoluted tubules (DCT), and its phosphorylation increases its transport activity and apical membrane localization. Although insulin has been reported to increase sodium reabsorption in the kidney, the linkage between insulin and NCC phosphorylation has not yet been investigated. This study examined whether insulin regulates NCC phosphorylation. In cultured mpkDCT cells, insulin increased phosphorylation of STE20/SPS1-related proline-alanine-rich kinase (SPAK) and NCC in a dose-dependent manner. This insulin-induced phosphorylation of NCC was suppressed in WNK4 and SPAK knockdown cells. In addition, Ly294002, a PI3K inhibitor, decreased the insulin effect on SPAK and NCC phosphorylation, indicating that insulin induces phosphorylation of SPAK and NCC through PI3K and WNK4 in mpkDCT cells. Moreover, acute insulin administration to mice increased phosphorylation of oxidative stress-responsive kinase-1 (OSR1), SPAK and NCC in the kidney. Time-course experiments in mpkDCT cells and mice suggested that SPAK is upstream of NCC in this insulin-induced NCC phosphorylation mechanism, which was confirmed by the lack of insulin-induced NCC phosphorylation in SPAK knockout mice. Moreover, insulin administration to WNK4 hypomorphic mice did not increase phosphorylation of OSR1, SPAK and NCC in the kidney, suggesting that WNK4 is also involved in the insulin-induced OSR1, SPAK and NCC phosphorylation mechanism in vivo. The present results demonstrated that insulin is a potent regulator of NCC phosphorylation in the kidney, and that WNK4 and SPAK are involved in this mechanism of NCC phosphorylation by insulin. [ABSTRACT FROM AUTHOR]

Background: Insulin-like growth factor 1 receptor (IGF1R) targeted therapies have resulted in responses in a small number of patients with advanced metastatic Ewing's sarcoma. We performed morphoproteomic profiling to better understand response/resistance mechanisms of Ewing's sarcoma to IGF1R inhibitor-based therapy. Methodology/Principal Findings: This pilot study assessed two patients with advanced Ewing's sarcoma treated with IGF1R antibody alone followed by combined IGF1R inhibitor plus mammalian target of rapamycin (mTOR) inhibitor treatment once resistance to single-agent IGF1R inhibitor developed. Immunohistochemical probes were applied to detect p-mTOR (Ser2448), p-Akt (Ser473), p-ERK1/2 (Thr202/Tyr204), nestin, and p-STAT3 (Tyr 705) in the original and recurrent tumor. The initial remarkable radiographic responses to IGF1R-antibody therapy was followed by resistance and then response to combined IGF1R plus mTOR inhibitor therapy in both patients, and then resistance to the combination regimen in one patient. In patient 1, upregulation of p-Akt and p-mTOR in the tumor that relapsed after initial response to IGF1R antibody might explain the resistance that developed, and the subsequent response to combined IGF1R plus mTOR inhibitor therapy. In patient 2, upregulation of mTOR was seen in the primary tumor, perhaps explaining the initial response to the IGF1R and mTOR inhibitor combination, while the resistant tumor that emerged showed activation of the ERK pathway as well. Conclusion/Significance: Morphoproteomic analysis revealed that the mTOR pathway was activated in these two patients with advanced Ewing's sarcoma who showed response to combined IGF1R and mTOR inhibition, and the ERK pathway in the patient in whom resistance to this combination emerged. Our pilot results suggests that morphoproteomic assessment of signaling pathway activation in Ewing's sarcoma merits further investigation as a guide to understanding response and resistance signatures. [ABSTRACT FROM AUTHOR]

Aim: The cytochrome P450 enzymes of the CYP26 family are involved in the catabolism of the biologically active retinoid all-trans-retinoic acid (atRA). Since it is possible that an increased local CYP26 activity would reduce the effects of retinoids in vascular injury, we investigated the role of CYP26 in the regulation of atRA levels in human aortic smooth muscle cells (AOSMCs). Methods: The expression of CYP26 was investigated in cultured AOSMCs using real-time PCR. The metabolism of atRA was analyzed by high-performance liquid chromatography, and the inhibitor R115866 or small interfering RNA (siRNA) was used to suppress CYP26 activity/expression. Results: AOSMCs expressed CYP26B1 constitutively and atRA exposure augmented CYP26B1 mRNA levels. Silencing of the CYP26B1 gene expression or reduction of CYP26B1 enzymatic activity by using siRNA or the inhibitor R115866, respectively, increased atRA-mediated signaling and resulted in decreased cell proliferation. The CYP26 inhibitor also induced expression of atRA-responsive genes. Therefore, atRA-induced CYP26 expression accelerated atRA inactivation in AOSMCs, giving rise to an atRA-CYP26 feedback loop. Inhibition of this loop with a CYP26 inhibitor increased retinoid signaling. Conclusion: The results suggest that CYP26 inhibitors may be a therapeutic alternative to exogenous retinoid administration. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: High doses of anti-inflammatory drugs, such as aspirin and salicylates, improve glucose metabolism in insulin resistant and type 2 diabetic patients. It has also been shown that the glucose lowering effect is related to the unspecific ability of these drugs to inhibit inhibitor kinaseβ (IKKβ). In this study we have investigated the effect of a selective IKKbinhibitor on beta cell survival and the prevention of diet induced type 2 diabetes in the gerbil Psammomys obesus (P. obesus). Methodology/Principal Findings: P. obesus were fed a diabetes inducing high energy diet for one month in the absence or presence of the IKKβ-inhibitor. Body mass, blood glucose, HbA1C, insulin production and pancreatic insulin stores were measured. The effects on beta cell survival were also studied in INS-1 cells and primary islets. The cells were exposed to IL-1β and subsequently reactive oxygen species, insulin release and cell death were measured in the absence or presence of the IKKβ-inhibitor. In primary islets and beta cells, IL-1β induced the production of reactive oxygen species, reduced insulin production and increased beta cell death, which were all reversed by pre-treatment with the IKKβ-inhibitor. In P. obesus the IKKβ-inhibitor prevented the development of hyperglycaemia and hyperinsulinaemia, and maintained pancreatic insulin stores with no effect on body weight. Conclusions/Significance: Inhibition of IKKβ activity prevents diet-induced diabetes in P. obesus and inhibits IL-1β induced reactive oxygen species, loss of insulin production and beta cell death in vitro. [ABSTRACT FROM AUTHOR]

Glycogen synthase kinase-3β (GSK-3β) is a key target and effector of downstream insulin signalling. Using comparative protein kinase assays and molecular docking studies we characterize the emodin-derivative 4-[N-2-(aminoethyl)-amino]-emodin (L4) as a sensitive and potent inhibitor of GSK-3β with peculiar features. Compound L4 shows a low cytotoxic potential compared to other GSK-3β inhibitors determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay and cellular ATP levels. Physiologically, L4 acts as an insulin-sensitizing agent that is able to enhance hepatocellular glycogen and fatty acid biosynthesis. These functions are particularly stimulated in the presence of elevated concentrations of glucose and in synergy with the hormone action at moderate but not high insulin levels. In contrast to other low molecular weight GSK-3β inhibitors (SB216763 and LiCl) or Wnt-3α-conditioned medium, however, L4 does not induce reporter and target genes of activated β-catenin such as TOPflash, Axin2 and glutamine synthetase. Moreover, when present together with SB216763 or LiCl, L4 counteracts expression of TOPflash or induction of glutamine synthetase by these inhibitors. Because L4 slightly activates β-catenin on its own, these results suggest that a downstream molecular step essential for activation of gene transcription by β-catenin is also inhibited by L4. It is concluded that L4 represents a potent insulin-sensitizing agent favouring physiological effects of insulin mediated by GSK-3β inhibition but avoiding hazardous effects such as activation of β-catenin-dependent gene expression which may lead to aberrant induction of cell proliferation and cancer. [ABSTRACT FROM AUTHOR]

The pancreatic beta cell is sensitive to even small changes in PDX1 protein levels; consequently, Pdx1 haploinsufficiency can inhibit beta cell growth and decrease insulin biosynthesis and gene expression, leading to compromised glucose-stimulated insulin secretion. Using metabolic labeling of primary islets and a cultured β cell line, we show that glucose levels modulate PDX1 protein phosphorylation at a novel C-terminal GSK3 consensus that maps to serines 268 and 272. A decrease in glucose levels triggers increased turnover of the PDX1 protein in a GSK3dependent manner, such that PDX1 phosphomutants are refractory to the destabilizing effect of low glucose. Glucose-stimulated activation of AKT and inhibition of GSK3 decrease PDX1 phosphorylation and delay degradation. Furthermore, direct pharmacologic inhibition of AKT destabilizes, and inhibition of GSK3 increases PDX1 protein stability. These studies define a novel functional role for the PDX1 C terminus in mediating the effects of glucose and demonstrate that glucose modulates PDX1 stability via the AKT-GSK3 axis. [ABSTRACT FROM AUTHOR]

Induced pluripotent stem cell technology has attracted enormous interest for potential application in regenerative medicine. Here, we report that a specific glycogen synthase kinase 3 (GSK-3) inhibitor, CHIR99021, can induce the reprogramming of mouse embryonic fibroblasts transduced by only two factors, Oct4 and Klf4. When combined with Parnate (also named tranylcypromine), an inhibitor of lysine-specific demethylase 1, CHIR99021 can cause the reprogramming of human primary keratinocyte transduced with the two factors, Oct4 and Klf4. To our knowledge, this is the first time that human iPS cells have been generated from somatic cells without exogenous Sox2 expression. Our studies suggest that the GSK-3 inhibitor might have a general application to replace transcription factors in both mouse and human reprogramming. [ABSTRACT FROM AUTHOR]

Abstract: In vivo and in vitro treatments were carried out to investigate the effects of apigenin-6-C-β-l-fucopyranoside (1), isolated from Averrhoa carambola L. (Oxalidaceae), on serum glucose and insulin levels in hyperglycemic rats as well as its effect on glycogen synthesis in normal rat soleus muscle. Apigenin-6-C-β-l-fucopyranoside showed an acute effect on blood glucose lowering in hyperglycemic rats and stimulated glucose-induced insulin secretion. A stimulatory effect of 1 on glycogen synthesis was observed when muscles were incubated with this flavonoid and also its effect was completely nullified by pre-treatment with insulin signal transduction inhibitors. Taking this into account, the MAPK–PP1 and PI3K–GSK3 pathways are involved in the apigenin-6-C-β-l-fucopyranoside-induced increase in glycogen synthesis in muscle. This study provides evidence for dual effects of apigenin-6-C-β-l-fucopyranoside as an antihyperglycemic (insulin secretion) as well as an insulinomimetic (glycogen synthesis) agent. [Copyright &y& Elsevier]

The article presents a study on the effects of transiently transfected mutant huntingtin on the insulin content and Akt activities. It notes that Huntington's disease (HD) is a neurological disorder wherein the protein huntingtin contains glutamine which repeats to expand about 37 more glutamines. With this, various methods are used including cell culture and transfection, fluorescent microscopy, and statistical analysis. The result shows link of insulin to the aggregate formation of huntingtin.

The dynamics of emerging nucleoside and nucleotide reverse-transcriptase inhibitor (NRTI) resistance in hepatitis B virus (HBV) are not well understood because standard dideoxynucleotide direct polymerase chain reaction (PCR) sequencing assays detect drug-resistance mutations only after they have become dominant. To obtain insight into NRTI resistance,we used a new sequencing technology to characterize the spectrum of low-prevalence NRTI-resistance mutations in HBV obtained from 20 plasma samples from 11 NRTI-treated patients and 17 plasma samples from 17 NRTI-naive patients, by using standard direct PCR sequencing and ultra-deep pyrosequencing (UDPS). UDPS detected drug-resistance mutations that were not detected by PCR in 10 samples from 5 NRTI-treated patients, including the lamivudine-resistance mutation V173L (in 5 samples), the entecavir-resistance mutations T184S (in 2 samples) and S202G (in 1 sample), the adefovir-resistance mutation N236T (in 1 sample), and the lamivudine and adefovir-resistance mutations V173L, L180M, A181T, and M204V (in 1 sample). G-to-A hypermutation mediated by the apolipoprotein BmRNA editing enzyme, catalytic polypeptide-like family of cytidine deaminases was estimated to be present in 0.6% of reverse-transcriptase genes. Genotype A coinfection was detected by UDPS in each of 3 patients in whom genotype G virus was detected by direct PCR sequencing. UDPS detected low-prevalence HBV variants with NRTI-resistance mutations, G-to-A hypermutation, and low-level dual genotype infection with a sensitivity not previously possible. [ABSTRACT FROM AUTHOR]

Polycystic ovaria n syndrome (PCOS) is the most frequent endocrine disorder and most common cause of anovulation in women of reproductive age. It is a heterogeneous disorder, characterized by excess androgen, ovulatory dysfunction and/or polycystic ovaries. The syndrome is known for its association with several reproductive problems, including infertility and obstetric adverse effects. In addition, significant long-term health problems have been strongly linked to PCOS, with women suffering from the disorder having a significantly higher risk of diabetes, cardiovascular risk and some types of cancer, such as endometrial cancer, Although its etiology is unknown, insulin resistance is believed to play a pivotal role in its pathophysiology, with insulin sensitizers found to provide an exciting option in managing health problems associated with PCOS. Almost a decade ago, we proposed a non-insulin-sensitizing mechanism of action for insulin sensitizers through their effect on steroidogenesis. Accumulating evidence supported such an assumption, with solid evidence for a modulating effect on steroidogenesis by metformin and glitazones in the ovaries, adrenal glands and fat cells, Furthermore, other exciting positive roles for insulin sensitizers, in particular glitazones, have been reported at the level of endothelial function. Studying the value of insulin sensitizers in preventing long-term health problems in women with PCOS is still in the stage of infancy. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinases (MMP) and the factors that are regulating their activity (tissue inhibitors of MMP - TIMP) plays a complementary role in stimulating or inhibiting the advance of ureteric bud in the mesenchime together with various growth factors. The inhibitors of matrix metalloproteinases can play also various roles in these processes. Even if there is a correspondence of the pairs MMP2-TIMP2 and MMP9-TIMP1, the relation between these enzymes and their specific inhibitors is especially complex. In order to complete the observations referring to co-localization of MMP2, MMP9 and TIMP2 we have used a molecular modeling technique in order to investigate the coupling possibilities between MMP2, 9 and the natural inhibitor TIMP2. The present study analyzes the possible conformations and interactions between MMP2, MMP9 with TIMP2. [ABSTRACT FROM AUTHOR]

It is hypothesized that a topical application of a sulfonylurea drug, which can inhibit the ATP-sensitive potassium-gated channels (Kir6.X/SUR) present in human hair bulb tissues, will inhibit hair growth in a targeted manner. Diazoxide is used to treat severe hypoglycemia due to hyperinsulinism of infancy. However, this often results in hypertrichosis that can be severe enough to prevent its use. Diazoxide blocks insulin release from the pancreas by opening the SUR1/Kir6.2 channels in ß-cells. Diazoxide can also act on two potassium-gated channels in the skin that affect hair growth, namely SUR1/Kir6.2 and SUR2B/Kir6.1, thus causing hypertrichosis. It is proposed that a topical sulfonylurea will inhibit the excessive hair growth due to diazoxide, but will not impact the beneficial effects of diazoxide on beta cells. This approach can also be applied to rare cases of Cantú syndrome, caused by mutations in ABCC9 (coding for SUR2) or in KCNJ8 (coding for Kir6.1) that is characterized by congenital hypertrichosis. More importantly, this approach may also be effective in treating other forms of hypertrichosis or hirsutism, that are quite common, yet very distressing to patients worldwide. [ABSTRACT FROM AUTHOR]

The article presents a study on antiretroviral therapy exposure and insulin resistance in interagency of HIV in women. It examined 1,614 HIV-infected and 604 HIV-uninfected participants from a study between October 2000 and March 2007 on women's interagency HIV with use of homeostasis model assessment (HOMA)-estimated insulin resitance (IR) at 11,019 semiannual visits. Result shows that longer nucleoside reverse transcriptase inhibitor (NRTI) was linked with greater IR in HIV-infected women.

Introduction: Choroidal neovascularization (CNV) is a debilitating complication of age-related macular degeneration (AMD) and a leading cause of vision loss. Along with other angiogenic factors like vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF-1) and its receptor, IGF-1R, have been implicated in CNV. Purpose: We have previously shown that the cyclolignan picropodophyllin (PPP) efficiently blocks the insulin-like growth factor-1 receptor (IGF-1R) activity and causes cell death in uveal melanoma cell lines and in an in-vivo model. In this study we investigated the effect of PPP on VEGF expression both in vitro and in vivo and whether this effect has anti-angiogenic consequences in a murine CNV model. Materials and Methods: C57BL/6J mice with laser-induced CNVs were treated with PPP. Effects on CNV area were assayed by image analysis. VEGF levels in choroids and retinal pigment epithelial cells (APRE-19) were measured by Western blot or ELISA. Transcriptional activation of the VEGF promoter was determined by luciferase reporter gene assay. Results: Mice treated with PPP, administered intraperitoneally or orally, showed 22–32% (p = 0.002) decrease in CNV area. Furthermore, VEGF levels in the choroids were significantly reduced. In cultured APRE-19 cells, IGF-1 was shown to increase VEGF secretion. This increase was completely blocked by PPP. We could confirm that PPP reduced the level of transcriptional activity of VEGF promoter. Conclusions: PPP reduces IGF-1 dependent VEGF expression and CNV in vivo. Accordingly, IGF-1R inhibitors may be useful tools in the therapy of conditions associated with CNV including neovascular AMD. [ABSTRACT FROM AUTHOR]

Abstract: We here report the design and synthesis of selective human lysosomal sialidase (NEU1) inhibitors. A series of amide-linked C9 modified DANA (2-deoxy-2,3-dehydro-N-acetylneuraminic acid) analogues were synthesized and their inhibitory activities against all four human sialidases (NEU1–NEU4) were determined. Structure-based approach was used to investigate the basis of selectivity of the compounds with experimentally observed activity. Results from the present study are found to be informative in a qualitative manner for the further design of isoform selective human sialidase inhibitors for therapeutic value. [Copyright &y& Elsevier]

Abstract: Miglitol, a pseudomonosaccharide alpha-glucosidase inhibitor (αGI), was more effective at reducing blood glucose levels at 30 and 60min after a meal than voglibose. Speculating that miglitol administered even after the start of a meal may be effective, we evaluated the timing of administration of miglitol on the plasma glucose and serum insulin levels in 13 type 2 diabetic patients. Miglitol was administered in four different intake manners in each patient (control: no miglitol; intake 1: just before breakfast; intake 2: 15min after the beginning of breakfast; intake 3: 30min after the beginning of breakfast). The area under the curve (AUC) of plasma glucose was significantly decreased under all the intake conditions, as compared with the AUC in the control. The AUC of serum insulin tended to be lower in all the three groups than in the control, although the differences were not statistically significant. Thus, miglitol administered anytime within 30min after the start of a meal is effective for glycemic control. These results suggest that if patients miss taking miglitol at the beginning of a meal, they can still take the drug until 30min after starting their meal. [Copyright &y& Elsevier]

The serine/threonine kinase glycogen synthase kinase-3 (GSK-3) was initially identified as a key regulator of insulin-dependent glycogen synthesis. GSK-3 was subsequently shown to function in a wide range of cellular processes including differentiation, growth, motility and apoptosis. Aberrant regulation of GSK-3 has been implicated in a range of human pathologies including Alzheimer’s disease, non-insulin-dependent diabetes mellitus (NIDDM) and cancer. As a consequence, the regulation of GSK-3 and the therapeutic potential of GSK-3 inhibitors have become key areas of investigation. This review will focus on the mechanisms of GSK-3 regulation, with emphasis on modulation by upstream signals, control of substrate specificity and GSK-3 localisation. The details of these mechanisms will be discussed in the context of specific signalling pathways. [ABSTRACT FROM AUTHOR]

Abstract: Transdermal delivery of insulin is a non-invasive alternative to the subcutaneous injection of insulin in diabetic patients. It has been found that skin pretreatment with iodine followed by a dermal application of insulin results in reduced glucose and elevated hormone levels in the plasma. Topical iodine protects the dermally applied insulin presumably by inactivation of endogenous sulfhydryls such as glutathione and gamma glutamylcysteine which can reduce the disulfide bonds of the hormone. Thus, the effect of iodine is mediated by retaining the potency of the hormone during its penetration via the skin into the circulation. The proposed procedure might be applicable for additional disulfide-containing peptides such as calcitonine, somatostatin, oxytocin/vasopressin and their analogs. [Copyright &y& Elsevier]

The majority of small G-proteins undergo posttranslational modifications (e.g., isoprenylation) at their C-terminal cysteine residues. Such modifications increase their hydrophobicity, culminating in translocation of the modified proteins to their relevant membranous sites for interaction with their respective effectors. Previously, we reported glucose-dependent activation and membrane association of Racl in INS 832/13 cells. We also demonstrated modulatory roles for Racl/GDP dissociation inhibitor in glucose-stimulated insulin secretion (GSIS) in INS 832/13 cells, further affirming roles for Racl in GSIS. Herein, we demonstrate that geranylgeranyltransferase inhibitor-2147 (GGTI-2147), an inhibitor of protein prenylation, markedly increased cytosolic accumulation of Racl and elicited significant inhibition of GSIS from INS 832/13 cells. In the current study, we also examined the localization of protein prenyltransferases (PPTases) and regulation of GSIS by PPTases in INS 832/13 cells. Western blot analyses indicated that the regulatory α-subunit and the structural β-subunit of PPTase holoenzyme are predominantly cytosolic in their distribution. Overexpression of an inactive mutant of the regulatory α-subunit of PPTase markedly attenuated glucose- but not KCl-induced insulin secretion from INS 832/13 cells. Together, our findings provide the first evidence for the regulation of GSIS by PPTase in INS 832/13 cells. Furthermore, they support our original hypothesis that prenylation of specific G-proteins may be necessary for GSIS. Diabetes 56:204-210, 2007 [ABSTRACT FROM AUTHOR]

p21cip1, a regulatory molecule upstream of the G1/0 checkpoint, is increased in β-cells in response to mitogenic stimulation. Whereas p21cip1 can variably stimulate or inhibit cell cycle progression, in vitro studies suggest that p21cip1 acts as an inhibitor in the pancreatic β-cell. To determine the functional role of p21cip1 in vivo, we studied p21-null mice. Surprisingly, islet mass, β-cell replication rates, and function were normal in p21-null mice. We next attempted to drive β-cell replication in p21-null mice by crossing them with rat insulin II promoter-murine PL-1 (islet-targeted placental lactogen transgenic) mice. Even with this added replicative stimulus of PL, p21-null islets showed no additional stimulation. A G1/S proteome scan demonstrated that p21cip1 loss was not associated with compensatory increases in other cell cycle inhibitors (pRb, p107, p130, p16, p19, and p27), although mild increases in p57 were apparent. Surprisingly, p18, which had been anticipated to increase, was markedly decreased. In summary, isolated p21cip1 loss, as for pRb, p53, p18, and p27 and other inhibitors, results in normal β-cell development and function, either because it is not essential or because its function is subserved or complimented by another protein. These studies underscore marked inhibitory pressure and the complexity and plasticity of inhibitory pathways that restrain β-cell replication. Diabetes 55: 3271-3278, 2006 [ABSTRACT FROM AUTHOR]

Abstract: Intensive treatment regimens including early initiation of insulin treatment are important to prevent late complications in type 2 diabetes. The assumed risk of severe hypoglycemia (SH) is a major barrier to initiation of insulin treatment. To assess the relevance of this risk we evaluated the frequency of SH as reported in the literature. Using Medline and Embase search we identified 11 studies (5 retrospective and 6 prospective) including at least 50 patients with insulin-treated type 2 diabetes followed for at least 6 months in which frequency of SH was reported. The incidence of SH in the retrospective studies varied from 15 to 73 episodes per 100 patient-year with a proportion of the patients having one or more episodes between 1.4 to 15%. In the prospective studies, both incidence rate and proportion of the patients having one or more episodes of SH were lower than in the retrospective studies. Only few studies looked into the impact of risk factors on the rate of SH. Impaired hypoglycemia awareness, high age, long duration of diabetes and insulin therapy increased the risk, while no association was found with HbA1c and insulin dose. The present knowledge of SH in insulin-treated type 2 diabetes is characterized by the paucity of data and the heterogeneity of the few studies available. Large and long-lasting studies with SH as primary endpoint are warranted in order to further clarify the occurrence of SH and influence of the risk factors in unselected patients with insulin-treated type 2 diabetes. [Copyright &y& Elsevier]

Abstract: Objective: Insulin need for a given degree of glucose control varies markedly among individuals. We examined which factors determine daily insulin use in patients with Type 1 diabetes. Methods: A cross-sectional study was performed in 416 patients. Clinical parameters, medication use, physical activity, smoking, alcohol consumption, and laboratory parameters were determined. Results: Body mass index and waist circumference were positively related to daily insulin use (2.3 U/kg/m2, 95% CI=1.9–2.7 and 0.8 U/cm, 95% CI=0.6–0.9, adjusted for age and sex). Age, female sex, and duration of diabetes were inversely related to daily insulin dose. There was an increase of 3.6 U of insulin per mmol/l triglycerides (95% CI=1.04–6.2) and a decrease of 5.9 U of insulin per mmol/l high-density lipoprotein cholesterol (95% CI=−10.0 to −1.8), adjusted for age, sex, and weight. For blood pressure-lowering drugs, the strongest relation was found for thiazide diuretics (difference of 7.1 U insulin/day, 95% CI=0.2–14.2, adjusted for age, sex, and weight). The use of an insulin pump and physical activity were related to lower daily insulin need: −8.7 U/day (95% CI=−11.8 to −5.5) and −1.7 U/day per activity score unit (95% CI=−3.2 to −0.2), respectively, adjusted for age, sex, and weight. Smoking was related to an increased need of 5.3 U/day (95% CI=1.5–9.0), adjusted for age, sex, and weight. Conclusions: Our results show that components of the metabolic syndrome are positively related to daily insulin use. Also, decreased physical activity, smoking, and the use of blood pressure-lowering drugs, which influence insulin sensitivity, are associated with an increased insulin need. These findings suggest that the presence of insulin resistance in Type 1 diabetes or “double diabetes” plays a key role in determining daily insulin need. [Copyright &y& Elsevier]

The aim of the present study was to evaluate the mediating role played by obesity on the relationship of free insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) with muscle strength and physical performance. Data were from baseline evaluation of the ilSIRENTE Study. Muscle strength was measured by hand grip strength. Physical performance was assessed using the walking speed and the 0–3 Short Physical Performance Battery (SPPB) score. Based on its median value, free IGF-I was categorized in the following two groups: low IGF-I (IGF-I <0.65 ng/ml; n = 174) and high IGF-I (IGF-I ≥0.65 ng/ml; n = 175). Similarly, IGFBP-3 was categorized in the following two groups: low IGFBP-3 (IGFBP-3 <4,319.9 ng/ml; n = 174) and high IGFBP-3 (IGFBP-3 ≥4,319.9 ng/ml; n = 175). Body mass index (BMI) was categorized as follows: <25 kg/m² (n = 160), 25–29.9 kg/m² (n = 133), ≥30 kg/m² (n = 56). Mean age of the 349 participants was 85.8 yr, and 234 (67%) were women. After adjusting for potential confounders, no significant association of IGF-I and IGFBP-3 with study outcomes was observed. After the study sample was stratified by BMI groups, compared with participants with low IGF-I level, those with high IGF-I level had a significantly better grip strength [35.2 ± 1.6 vs. 29.2 ± 2.0 (SE) kg, P = 0.03], walking speed (0.55 ± 0.04 vs. 0.40 ± 0.04 m/s, P = 0.01), and SPPB score (1.9 ± 0.1 vs. 1.5 ± 0.1 m/s, P = 0.01) but only in the group with BMI ≥30 kg/m² and not in other BMI groups. A statistically significant interaction between BMI and IGF-I level was observed on all study outcomes. By contrast, no association was observed between IGFBP-3 and study outcomes, independently of BMI. In conclusion, high IGF-I level is associated with better physical function in older persons with obesity, but not in nonobese subjects. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of 5-aminoimidazole-4-carboxamide-1-β-ᴅ-ribofuranoside (AICAR)-induced AMP-activated protein kinase (AMPK) activation on basal and insulin-stimulated glucose and fatty acid metabolism in isolated rat adipocytes. AICAR-induced AMPK activation profoundly inhibited basal and insulin-stimulated glucose uptake, lipogenesis, glucose oxidation, and lactate production in fat cells. We also describe the novel findings that AICAR-induced AMPK phosphorylation significantly reduced palmitate (32%) and oleate uptake (41%), which was followed by a 50% reduction in palmitate oxidation despite a marked increase in AMPK and acetyl-CoA carboxylase phosphorylation. Compound C, a selective inhibitor of AMPK, not only completely prevented the inhibitory effect of AICAR on palmitate oxidation but actually caused a 2.2-fold increase in this variable. Compound C also significantly increased palmitate oxidation in the presence of inhibitory concentrations of malonyl-CoA and etomoxir indicating an increase in CPT1 activity. In contrast to skeletal muscle in which AMPK stimulates fatty acid oxidation to provide ATP as a fuel, we propose that AMPK activation inhibits lipogenesis and fatty acid oxidation in adipocytes. Inhibition of lipogenesis would conserve ATP under conditions of cellular stress, although suppression of intra-adipocyte oxidation would spare fatty acids for exportation to other tissues where their utilization is crucial for energy production. Additionally, the stimulatory effect of compound C on long chain fatty acid oxidation provides a novel pharmacological approach to promote energy dissipation in adipocytes, which may be of therapeutic importance for obesity and type II diabetes. [ABSTRACT FROM AUTHOR]

Abstract: The transfer of sialic acids to the non-reducing terminal positions on sugar chains of glycoconjugates is catalyzed by sialyltransferases (STs). Increased sialylation is correlated with oncogenic transformation and metastatic potential. ST inhibitors may be potentially valuable as anti-cancer and anti-metastatic agents. In this study, we evaluated the effects of soyasaponin I (Ssa I), a known inhibitor of STs, on tumor metastasis through studying a highly metastatic cancer cell line B16F10. Ssa I specifically inhibited the expression of α2,3-linked sialic acids without affecting other glycans on the B16F10 cell surface. We also found that Ssa I decreased the migratory ability of cells, enhanced cell adhesion to extracellular matrix proteins. Finally, a pulmonary metastasis assay demonstrated that alteration of glycosylation in this way significantly reduced the ability of tumor cells to distribute to the lungs of mice. Collectively, these findings suggested that α2,3-linked sialic acids may play an important role in metastasis potential of B16F10 cells. [Copyright &y& Elsevier]

Aims/hypothesis: The incretin hormone glucagon-like peptide 1 (GLP-1) has antihyperglycaemic effects, but its therapeutic usefulness is limited by its metabolic instability. Dipeptidyl peptidase IV (DPP-IV) is established as the primary inactivating enzyme, but the roles of other enzymes remain unclear. Methods: The effect of candoxatril, a selective inhibitor of neutral endopeptidase (NEP) 24.11, on GLP-1 pharmacokinetics/pharmacodynamics with or without DPP-IV inhibition was examined in anaesthetised pigs. Results: During GLP-1 infusion, candoxatril doubled C-terminal immunoreactivity, improving the pharmacokinetics (t½ 2.3±0.1 to 8.8±1.2 min; metabolic clearance rate [MCR] 20.4±3.4 to 4.8±0.4 ml·kg-1·min-1; p«0.01), but had no effect upon intact GLP-1 (t½ 1.4±0.1 to 1.6±0.1 min; MCR 47.9±8.0 to 38.8±5.0 ml·kg-1·min-1). Insulin responses to intravenous glucose were unaffected by candoxatril, but glucose tolerance was improved (ΔAUCmin 27–87 118±5 to 74±14 min·mmol·l-1; glucose elimination rate [k] 6.6±0.5 to 8.6±0.5%; p«0.05). When candoxatril was co-administered with valine pyrrolidide (a DPP-IV inhibitor), changes in C-terminal GLP-1 pharmacokinetics mirrored those seen when candoxatril alone was administered (t½ 2.7±0.3 and 7.7±0.8 min; MCR 17.3±2.6 and 6.5±0.8 ml·kg-1·min-1 for valine pyrrolidide without and with candoxatril, respectively). However, intact GLP-1 pharmacokinetics were improved (t½ 2.8± 0.3 and 7.5±0.6 min; MCR 18.3±0.6 and 9.4±0.9 ml·Kg-1·min-1; p«0.02), potentiating the antihyperglycaemic/insulinotropic effects of GLP-1 (glucose ΔAUCmin 27–87 103±8 to 62±14 min·mmol·l-1; k 6.8±0.4 to 11.4±1.4%; insulin ΔAUCmin 27–87 3,680±738 to 7,201±1,183 min·pmol·l-1; p«0.05). Conclusions/interpretation: This study confirms a role for NEP-24.11 in GLP-1 metabolism in vivo, suggesting that up to 50% of GLP-1 entering the circulation may be degraded by NEP-24.11. Furthermore, combined inhibition of DPP-IV and NEP-24.11 is superior to DPP-IV inhibition alone in preserving intact GLP-1, which raises the possibility that the combination has therapeutic potential. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of long-term treatment with the dipeptidyl peptidase inhibitor P32/98 and its combination with rosiglitazone on blood glucose control and islet of Langerhans histology in male Zucker diabetic fatty (ZDF) rats, when treatment begins before or after the development of overt diabetes.ZDF rats were treated with P32/98 from the age of 9, 12 or 15 weeks. Rosiglitazone maleate was given to a separate group from the age of 13 weeks. P32/98 was given to all of these rosiglitazone-treated rats from 16 weeks of age. Rosiglitazone maleate was also given from 16 weeks of age to half the rats that were given P32/98 from 9 weeks of age. The compounds were given by oral gavage until the rats were 14 weeks old and then in the diet. The experiment was terminated at the age of 20–21 weeks. Blood glucose, plasma insulin and oral glucose tolerance were measured at intervals; islet histology was assessed terminally.P32/98 improved glucose tolerance after both single and multiple doses when treatment started at 9 weeks of age, also after the third week of treatment when treatment began at 12 or 15 weeks of age. P32/98 reduced daytime blood glucose when treatment began at 12 weeks. Treatment with rosiglitazone increased food intake and body weight, and after 2 weeks, reduced daytime blood glucose, water intake and the area under the glucose tolerance curve. A single dose of P32/98 markedly improved glucose tolerance in rosiglitazone-treated rats. When treatment had begun at 9 weeks of age, P32/98 stimulated insulin secretion in some glucose tolerance tests. Neither P32/98 nor rosiglitazone affected pancreatic insulin content, nor did they have clear effects on islet histology.P32/98 elicited a sustained improvement in glucose tolerance in both prediabetic and diabetic ZDF rats. The effects of P32/98 on glucose and insulin were similar to those of rosiglitazone, and in contrast to rosiglitazone, P32/98 did not increase food intake or body weight. However, neither compound was especially effective at improving diabetes in ZDF rats when treatment began at 9, 12 or 15 (P32/98) or 13 (rosiglitazone) weeks of age. [ABSTRACT FROM AUTHOR]

Presents a study on Caffeoylsophorose, a new natural α-glucosidase inhibitor, from red vinegar by fermented purple-fleshed sweet potato. Investigation of the suppressive effect on the postprandial blood glucose rise through α-glucosidase inhibition in order to clarify an antihyperglycemic function pf 6-O-caffeoylsophorose (CS) from diacylated anthocyanin; Administration of CS (100mg/kg) following maltose (2g/kg) to Sprague-Dawley rats; Results that indicate the non-competitive maltase inhibition of CS was partly due to acylation by phenolic acid with sugar.

SummaryIn studies designed to evaluate the therapeutic window for treatment of traumatic brain injury, the caspase 3 inhibitor z-DEVD-fmk improved neurologic function and reduced lesion volumes when administered at 1 but not at 4, 8, or 24 hours after injury. Moreover, neither caspase 3 nor PARP, a caspase 3 substrate, were cleaved in injured, untreated cortex from 1 to 72 hours after injury. Few cortical neurons expressed active caspase 3 or were TUNEL positive from 6 to 24 hours after injury, and TUNEL staining was primarily Type I (necrotic). Nissl staining revealed extensive neuronal necrosis in the injured cortex from 6 to 24 hours after impact. Considered together, these data suggested that z-DEVD-fmk may reduce neuronal necrosis, so we used an in vitro model of necrotic cell death induced by maitotoxin to test this further and explore the potential mechanism(s) involved. Z-DEVD-fmk (1 nM-100 μM) significantly attenuated maitotoxin induced neuronal cell death and markedly reduced expression of the 145 kD calpain-mediated α-spectrin breakdown product after maitotoxin injury. Neither the 120 kD caspase-mediated α-spectrin cleavage product nor cathepsin B were expressed after maitotoxin injury. In a cell free assay, z-DEVD-fmk reduced hydrolysis of casein by purified calpain I. Finally, z-DEVD-fmk reduced expression of the 145 kD calpain-mediated α-spectrin cleavage fragment after traumatic brain injury in vivo. These data suggest that neuroprotection by z-DEVD-fmk may, in part, reflect inhibition of calpain-related necrotic cell death.Journal of Cerebral Blood Flow & Metabolism (2004) 24, 1119–1132; doi:10.1097/01.WCB.0000138664.17682.32 [ABSTRACT FROM AUTHOR]

3-Hydroxy 3-methylglutaryl coenzyme A (HMG-coA) reductase inhibitors (statins) are the primary treatment in the management of atherosclerotic vascular disease. The benefits of statin treatment are believed to result from their capacity to lower LDL-cholesterol (LDL-C). However, lowering cholesterol alone cannot explain all of the beneficial effects of statin treatment. Recent findings suggest that statins invoke a generalized anti-inflammatory action. [Copyright &y& Elsevier]

Obesity and its attendant disorders, such as type 2 diabetes, are global health problems. We previously reported that C75, an inhibitor of fatty acid synthase (FAS) and stimulator of carnitine palmitoyltransferase I (CPT I), caused anorexia and profound weight loss in lean and genetically obese mice. To approximate human obesity, we utilized a chronic C75 treatment model for diet-induced obese (DIO) mice. Chronic C75 treatment decreased food consumption and increased energy expenditure due to increased fatty acid oxidation in both DIO and lean mice. There was a substantial loss of adipose tissue and resolution of hepatic steatosis in C75-treated DIO mice. Analysis of changes in the expression of hypothalamic neuropeptides demonstrated that the reduced food consumption in C75-treated DIO mice was accompanied by an increase in cocaine and amphetamine-related transcript expression but not by changes in neuropeptide Y such as seen with acute C75 treatment of lean mice. Inhibition of FAS and stimulation of CPT I provide a means to achieve stable, sustained weight loss in DIO mice. [ABSTRACT FROM AUTHOR]

Activation of the classical complement pathway is crucially involved in complement-mediated endothelial cell damage in ischemia-reperfusion injury. C1 inhibitor is the only known physiological inhibitor of classical complement pathway activation. Transgenic mice overexpressing human C1 inhibitor were used in a surgical lower torso and a liver ischemia-reperfusion model. Organ-specific endothelial disruption was determined by 125I-tagged albumin extravasation. In the lower torso ischemia-reperfusion model, transgenic mice overexpressing the C1 inhibitor were protected in the muscle and the lungs from endothelial cell damage. In the liver ischemia-reperfusion model, endothelial cell integrity was preserved in transgenic animals in the liver, the gut and the lungs. Our data indicate that inhibiting complement activation by a transgenic approach is effective in protection against ischemia-reperfusion injury. Copyright © 2004 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Dimethylaminopurine (DMAP) has previously been used as an inhibitor of phosphorylation in studies of meiotic events, and more recently to investigate TNFα signaling, because of its potential to inhibit activation of c-jun N-terminal kinase (JNK). Here we have addressed the effects of DMAP on metabolic insulin responses in adipocytes and on intracellular insulin signaling molecules.At 100 μmol/L, DMAP completely inhibited the ability of insulin to counteract lipolysis in isolated adipocytes. Insulin-induced lipogenesis and glucose uptake was inhibited to a lesser degree in a concentration-dependent manner starting at 10 μmol/L DMAP. Insulin-induced tyrosine phosphorylation of the insulin receptor was not affected by DMAP. Insulin-induced activation of protein kinase B, a known mediator of insulin action, was not inhibited by 100 μmol/L, but to a low extent by 1 mmol/L DMAP in intact cells. This inhibition was not sufficient to affect activation of the downstream protein kinase B substrate phosphodiesterase 3B.The inhibition of activation of JNK as a possible mechanism whereby DMAP affects insulin-induced antilipolysis, lipogenesis, and glucose uptake, was investigated using the JNK inhibitor SP600125. At 100 μmol/L, SP600125 completely reversed the antilipolytic effect of insulin, as well as partially inhibited insulin-induced lipogenesis and glucose-uptake, indicating that JNK may be involved in mediating these actions of insulin. Inhibition of JNK by DMAP may therefore partly explain the negative impact of DMAP on insulin action in adipocytes. [Copyright &y& Elsevier]

The disulfide bonds of the Na+/glucose cotransporter (SGLT1) are believed to participate in the binding of the transport inhibitor phlorizin. Here, we investigated the role of the [560–608] disulfide bond on the phlorizin-binding function of the C-terminal loop 13 of SGLT1 using 3-iodoacetamidophlorizin (3-IAP) as a probe. The reactivity of 3-IAP to the fully reduced loop 13 was competitively inhibited by phlorizin, as evident from the MALDI mass spectra. It indicates that the disulfide bond is not mandatory for phlorizin binding. CD and equilibrium unfolding studies showed that the secondary structure and conformation stability of loop 13 were not affected by removing the disulfide bond. Furthermore, we generated a series of loop 13 mutants to assess the contribution of the disulfide bond to phlorizin binding. A positive correlation between the stability and phlorizin affinity of the mutant proteins was observed, implying that the protein stability, rather than the disulfide bond, is relevant to the phlorizin-binding function of loop 13. [Copyright &y& Elsevier]

The central role of adipose tissue hormone-sensitive lipase in regulating fatty acid metabolism makes it a potential pharmacological target for the prevention of peripheral insulin resistance in obese, prediabetic and diabetic individuals. The synthesis of a new series of carbazates is presented. Modification of the phenolic 4-position in a series of 1,2,3,4-tetrahydroisoquinoline and morpholine derived carbazates, yielded inhibitors of the catalytic activity of this enzyme with nanomolar potency. [Copyright &y& Elsevier]