Insulin-resistant States Research Articles

Validation of a physiological type 2 diabetes model in human periodontal ligament stem cells.

Type 2 diabetes (T2DM), a recognized risk factor for periodontitis, is characterized by insulin resistance. However, the molecular mechanisms concerning the role of insulin resistance in linking T2DM and periodontitis remain poorly elucidated due to the absence of an appropriate T2DM cell model. We aimed to explore an appropriate model of T2DM in human periodontal ligament stem cells (hPDLSCs) and uncover the involved mechanisms. hPDLSCs were incubated with common reagents for recapitulating insulin resistance state including high glucose (HG) (15, 25, 35, 45 mM), glucosamine (0.8, 8, 18, 28, 38 mM), or palmitic acid (PA; 100, 200, 400, 800 μM), combined with LPS for 48 h. The insulin signaling pathway, inflammation, and pyroptosis were detected by western blots and quantitative real-time polymerase chain reaction (RT-qPCR). The effects on osteogenesis were evaluated by alkaline phosphatase staining, alizarin red S staining, RT-qPCR, and western blots. HG failed to recapitulate insulin resistance. Glucosamine was sufficient to induce insulin resistance but failed to trigger inflammation. In total, 100 and 200 μM PA exhibited the most proinflammatory, insulin resistance, and pyroptosis induced role, and inhibited the osteogenic differentiation of hPDLSCs. Palmitic acid is a promising candidate for developing T2DM model in hPDLSCs.

F6P/G6P-mediated ChREBP activation promotes the insulin resistance-driven hepatic lipid deposition in zebrafish

Insulin-sensitive lipogenesis dominates the body lipid deposition; however, nonalcoholic fatty liver disease (NAFLD) develops in the insulin-resistant state. The regulation mechanism of insulin resistance-driven NAFLD remains elusive. Using zebrafish model of insulin resistance (ZIR, insrb−/−) and mouse hepatocytes (NCTC 1469), we explored the regulation mechanism of insulin resistance-driven hepatic lipid deposition under the stimulation of carbohydrate diet (CHD). In ZIR model, insulin resistance induced hyperlipidemia and elevated hepatic lipid deposition via elevating the gene/protein expressions of lipogenic enzymes, that was activated by carbohydrate response element binding protein (ChREBP), rather than sterol regulatory element binding proteins 1c (SREBP-1c). The metabolomic analysis in zebrafish and silencing of chrebp in mouse hepatocytes revealed that the increased hepatic frucotose-6-phosphate (F6P) and glucose-6-phosphate (G6P) promoted the ChREBP-mediated lipid deposition. We further identified that F6P alone was sufficient to activate ChREBP-mediated lipid deposition by a SREBP-1c-independent manner. Moreover, we clarified the suppressed hepatic phosphofructokinase/glucose-6-phosphatase functions and the normal glucokinase function preserved by glucose transporter 2 (GLUT2) manipulated the increased F6P/G6P content in ZIR. In conclusion, the present study revealed that insulin resistance promoted hepatic lipid deposition via the F6P/G6P-mediated ChREBP activation. Our findings deciphered the main regulation pathway for the liver lipid deposition in the insulin-resistant state and identified F6P as a new potential regulator for ChREBP.

Black mulberry extract inhibits hepatic adipogenesis through AMPK/mTOR signaling pathway in T2DM mice

Ethnopharmacological relevanceBlack mulberry (Morus nigra L.) is an ancient dual-use plant resource for medicine and food. It is widely used in Uyghur folklore for hypoglycemic treatment and is a folkloric plant medicine with regional characteristics. However, the mechanism of Morus nigra L. treatment in diabetes mellitus has not been fully understood, especially from the perspective of hepatic lipid accumulation is less reported. Objective of this studyThis study was to explore the potential of Morus nigra L. fruit ethyl acetate extract (MNF-EA) to reduce blood sugar levels by preventing the production of hepatic lipogenesis and to provide more evidence for the use of MNF-EA as an adjuvant therapy for type 2 diabetes mellitus (T2DM). Materials and methodsIn this study, the chemical composition of MNF-EA was first analyzed and characterized using UPLC-Q-TOF-MS technique. A series of in vitro studies were performed with HepG2-IR cells and oleic acid (OA)-induced HepG2 cells, including MTT assay, glucose uptake assay, oil red O staining and Western blot analysis. The STZ-HFD co-induced T2DM mice were employed for in vivo research, including physical indices, biochemical analysis, histopathological examination, and Western blot analysis. ResultsThe 19 compounds in MNF-EA were identified by UPLC-Q-TOF-MS technique. Insulin resistance (IR) and lipid droplet accumulation in HepG2 cells were greatly improved by MNF-EA treatment, which had no appreciable side effects at the dosage used. In T2DM mice, MNF-EA decreased fasting blood glucose (FBG), saved body weight, and significantly improved oral glucose tolerance (OGTT) and IR status. In addition, MNF-EA treatment also improved lipid metabolism disorders and liver function in T2DM mice. Histopathological sections showed that MNF-EA treatment reduced hepatic steatosis. Mechanistic studies suggest that MNF-EA acted through the AMPK/mTOR pathway. ConclusionsThese results suggest that MNF-EA has great potential to reverse the metabolic abnormalities associated with T2DM by regulating the AMPK/mTOR signaling pathway. Therefore, we believe that MNF is a promising medicinal and food-homologous agent to improve T2DM.

Association between Altered Thyroid Function and Prediabetes in Diet-Induced Prediabetic Male Sprague Dawley Rats

There is a correlation between the existence of type 2 diabetes mellitus (T2DM) and the development of thyroid disorders. Prediabetes is a progressive state of moderate insulin resistance that often precedes the onset of T2DM. However, the association between prediabetes and thyroid function is unknown. This study assessed changes in markers of thyroid function in diet-induced prediabetes. Twelve male Sprague Dawley rats (n = 12) were randomly assigned into two groups. Rats in the non-prediabetic (NPD) group were fed a standard rat diet, while rats in the prediabetic (PD) were fed a high-fat high-carbohydrate diet for 20 weeks to induce prediabetes. Thereafter, fasting blood glucose levels were measured. Plasma samples were assessed for triiodothyronine (T3), thyroxine (T4), thyroxine peroxidase (TPO) antibody, insulin, and glycated hemoglobin (HbA1c) concentrations. The elevated blood glucose, HbA1c, and plasma insulin levels coincided with increased T3 and reduced T4 levels in the PD group when compared to the NPD group. There was also an increase in the concentration of TPO antibodies in the PD group. Additionally, there was a significant correlation between the thyroid hormone concentrations and HbA1c levels. In conclusion, these results indicated that there is a positive association between thyroid dysfunction and diet-induced prediabetes in rats.

Partial skeletal muscle-specific Drp1 knockout enhances insulin sensitivity in diet-induced obese mice, but not in lean mice

ObjectiveDynamin-related protein 1 (Drp1) is the key regulator of mitochondrial fission. We and others have reported a strong correlation between enhanced Drp1 activity and impaired skeletal muscle insulin sensitivity. This study aimed to determine whether Drp1 directly regulates skeletal muscle insulin sensitivity and whole-body glucose homeostasis. MethodsWe employed tamoxifen-inducible skeletal muscle-specific heterozygous Drp1 knockout mice (mDrp1+/−). Male mDrp1+/− and wildtype (WT) mice were fed with either a high-fat diet (HFD) or low-fat diet (LFD) for four weeks, followed by tamoxifen injections for five consecutive days, and remained on their respective diet for another four weeks. In addition, we used primary human skeletal muscle cells (HSkMC) from lean, insulin-sensitive, and severely obese, insulin-resistant humans and transfected the cells with either a Drp1 shRNA (shDrp1) or scramble shRNA construct. Skeletal muscle and whole-body insulin sensitivity, skeletal muscle insulin signaling, mitochondrial network morphology, respiration, and H2O2 production were measured. ResultsPartial deletion of the Drp1 gene in skeletal muscle led to improved whole-body glucose tolerance and insulin sensitivity (P < 0.05) in diet-induced obese, insulin-resistant mice but not in lean mice. Analyses of mitochondrial structure and function revealed that the partial deletion of the Drp1 gene restored mitochondrial dynamics, improved mitochondrial morphology, and reduced mitochondrial Complex I- and II-derived H2O2 (P < 0.05) under the condition of diet-induced obesity. In addition, partial deletion of Drp1 in skeletal muscle resulted in elevated circulating FGF21 (P < 0.05) and in a trend towards increase of FGF21 expression in skeletal muscle tissue (P = 0.095). In primary myotubes derived from severely obese, insulin-resistant humans, ShRNA-induced-knockdown of Drp1 resulted in enhanced insulin signaling, insulin-stimulated glucose uptake and reduced cellular reactive oxygen species (ROS) content compared to the shScramble-treated myotubes from the same donors (P < 0.05). ConclusionThese data demonstrate that partial loss of skeletal muscle-specific Drp1 expression is sufficient to improve whole-body glucose homeostasis and insulin sensitivity under obese, insulin-resistant conditions, which may be, at least in part, due to reduced mitochondrial H2O2 production. In addition, our findings revealed divergent effects of Drp1 on whole-body metabolism under lean healthy or obese insulin-resistant conditions in mice.

Acyl-CoA synthetase expression in human skeletal muscle is reduced in obesity and insulin resistance.

Upon intramuscular entry, fatty acids are converted to amphiphatic fatty acyl-CoAs by action of the acyl-CoA synthetase (ACS) enzymes. While it has been reported that insulin resistant skeletal muscle shows an accumulation of fatty acyl-CoAs, the role of the enzymes which catalyze their synthesis is still sparsely studied in human muscle, in particular the influence of obesity, and insulin resistance. We analyzed muscle biopsies obtained from normal weight controls (n = 7, average BMI 24), males/females with obesity (n = 7, average BMI 31), and males/females with obesity and type 2 diabetes (T2D) (n = 7, average BMI 34), for relevant ACS (long-chain acyl-CoA synthetase 1 (ACSL1), -3 (ACSL3) and - 4 (ACSL4), fatty acid transport protein 1 (FATP1) and - 4 (FATP4)). The mRNA expression was determined by real-time PCR, and total oleoyl-CoA synthetase activity was measured. In the males/females with obesity and T2D, the response to 16 weeks of exercise training with minor weight loss was evaluated. ACSL1 is the dominantly expressed ACS isoform in human skeletal muscle. The content of total ACS mRNA, as well as ACSL1 mRNA, were lower in muscle of males/females with obesity and T2D. Exercise training in the males/females with obesity and T2D increased the total ACS enzyme activity, along with a lowering of the HOMA-IR index. The capacity for synthesis of fatty acyl-CoAs is lower in skeletal muscle of obese males/females with T2D. This suggests a decreased ability to convert fatty acids to fatty acyl-CoAs, which in turn may affect their entry into storage or metabolic pathways in muscle. Thus, the accumulation of fatty acyl-CoAs in the obese or insulin resistant state that has been shown in previous reports is not likely to result from increased fatty acid acylation. The upregulation of ACS activity by exercise training appears beneficial and occurred concomitantly with increased insulin sensitivity.

Impact of obesity on liver function tests: is nonalcoholic fatty liver disease the only player? A review article.

Obesity and nonalcoholic fatty liver disease (NAFLD) are common worldwide health problems with a strong relationship in between. NAFLD is currently the most common cause of abnormal liver function tests (LFT) because of obesity pandemic. The question is NAFLD the only player of abnormal LFT in obesity? This article reviews the most important topics regarding the derangements of LFT in obesity through a PubMed search strategy for all English-language literature. The reported abnormal LFT in obesity were increased serum levels of transaminases (alanine aminotransaminase, aspartate aminotransaminase), gamma glutamyl transferase, and alkaline phosphatase and decreased serum levels of bilirubin and albumin. Besides novel potential hepatic markers of NAFLD/NASH such as triglycerides/high-density lipoprotein cholesterol ratio, sex hormone-binding globulin, fibroblast growth factor 21, and markers of hepatocyte apoptosis i.e. cytokeratin 18 and microribonucleic acids (miRNAs). Beyond NAFLD, there are other underlying players for the abnormal LFT in obesity such as oxidative stress, inflammation, and insulin resistance. Derangements of LFT in obesity are attributed to NAFLD but also to obesity itself and its related oxidative stress, insulin resistance, and chronic inflammatory state. Abnormal LFT predict more than just liver disease.

Effectiveness of Rosmarinus officinalis and Centella asiatica Nanoemulsions Against Caspase 3 Gestational Diabetes Mellitus Expression

Gestational diabetes mellitus (GDM) is closely related to oxidative stress conditions in insulin resistance conditions that increase Reactive Oxygen Species (ROS) against the body's defense antioxidant mechanism. Chronic complications due to hyperglycemia in patients with GDM increase BAX / BCL2 levels which then activates the change of procaspase 3 to caspase 3, an activator of apoptosis. This study aims to determine the effect of the combination of Rosmarinus officinalis and Centella asiatica nanoemulsions on caspase 3 expressions in zebrafish models of gestational diabetes mellitus, with a posttest-only controlled group design. The samples were divided into five groups, namely K- (EM), K+(EM+3% Glucose), P1, P2 and P3 (3% Glucose + Combination of Rosmarinus officinalis and Centella asiatica 2.5μg/ml, 5μg/ml and 10μg/ml), which will be tested for PEPCK and Caspase expression at the age of 3dpf using Real Time-PCR. The results of the correlation test of the group with caspase 3 obtained (p = 0.045) negative direction. These results show that the combination of Rosmarinus officinalis and Centella asiatica nanoemulsion decreased Caspase 3 expression in zebrafish models of gestational diabetes mellitus. The combination of Rosmarinus officinalis and Centella asiatica nanoemulsion has the potential to reduce blood glucose levels and reduce the risk of apoptosis in gestational diabetes mellitus patients.

Brain Dopamine-Clock Interactions Regulate Cardiometabolic Physiology: Mechanisms of the Observed Cardioprotective Effects of Circadian-Timed Bromocriptine-QR Therapy in Type 2 Diabetes Subjects.

Despite enormous global efforts within clinical research and medical practice to reduce cardiovascular disease(s) (CVD), it still remains the leading cause of death worldwide. While genetic factors clearly contribute to CVD etiology, the preponderance of epidemiological data indicate that a major common denominator among diverse ethnic populations from around the world contributing to CVD is the composite of Western lifestyle cofactors, particularly Western diets (high saturated fat/simple sugar [particularly high fructose and sucrose and to a lesser extent glucose] diets), psychosocial stress, depression, and altered sleep/wake architecture. Such Western lifestyle cofactors are potent drivers for the increased risk of metabolic syndrome and its attendant downstream CVD. The central nervous system (CNS) evolved to respond to and anticipate changes in the external (and internal) environment to adapt survival mechanisms to perceived stresses (challenges to normal biological function), including the aforementioned Western lifestyle cofactors. Within the CNS of vertebrates in the wild, the biological clock circuitry surveils the environment and has evolved mechanisms for the induction of the obese, insulin-resistant state as a survival mechanism against an anticipated ensuing season of low/no food availability. The peripheral tissues utilize fat as an energy source under muscle insulin resistance, while increased hepatic insulin resistance more readily supplies glucose to the brain. This neural clock function also orchestrates the reversal of the obese, insulin-resistant condition when the low food availability season ends. The circadian neural network that produces these seasonal shifts in metabolism is also responsive to Western lifestyle stressors that drive the CNS clock into survival mode. A major component of this natural or Western lifestyle stressor-induced CNS clock neurophysiological shift potentiating the obese, insulin-resistant state is a diminution of the circadian peak of dopaminergic input activity to the pacemaker clock center, suprachiasmatic nucleus. Pharmacologically preventing this loss of circadian peak dopaminergic activity both prevents and reverses existing metabolic syndrome in a wide variety of animal models of the disorder, including high fat-fed animals. Clinically, across a variety of different study designs, circadian-timed bromocriptine-QR (quick release) (a unique formulation of micronized bromocriptine-a dopamine D2 receptor agonist) therapy of type 2 diabetes subjects improved hyperglycemia, hyperlipidemia, hypertension, immune sterile inflammation, and/or adverse cardiovascular event rate. The present review details the seminal circadian science investigations delineating important roles for CNS circadian peak dopaminergic activity in the regulation of peripheral fuel metabolism and cardiovascular biology and also summarizes the clinical study findings of bromocriptine-QR therapy on cardiometabolic outcomes in type 2 diabetes subjects.

Assessment of Serum Apelin Levels and Its Relation to Insulin Resistance in Acne Vulgaris Patients

Abstract Introduction Apelin is one of the adipokines. Acne vulgaris is a very common dermatological disease with a multifactorial background and hyperinsulinemia and insulin resistance are considered to play a pivotal role in its development and severity. Aim To evaluate serum apelin levels in acne vulgaris patients and to reveal the possible relation between its serum levels and the insulin resistance state in acne vulgaris patients. Material and methods Thirty-two acne vulgaris patients and thirty-two healthy controls were enrolled into the study. The blood levels of apelin, insulin and glucose were measured in patients and controls. Homeostasis model assessment index (HOMA-IR) was calculated to evaluate the insulin resistance state. Results Acne vulgaris patients experienced significant higher levels of fasting insulin, serum apelin, and HOMA-IR compared to controls. Conclusions These results suggest that serum apelin and insulin resistance may have a role in the pathogenesis of acne.

Evaluation of Serum Visfatin Level and Its Relation to Insulin Resistance in Patients with Inflammatory Acne Vulgaris

Abstract Acne vulgaris is a multifactorial pilosebaceous unit disorder, with histological, immunological and evidence suggesting inflammatory involvement in its different stages. Acne vulgaris possess psychological impact on affected patients due to facial disfigurement especially if severe. Visfatin is an adipokine of proinflammatory characteristics. It was related to insulin resistance, obesity and some inflammatory skin diseases. Aim of the Study The current study aimed to evaluate serum visfatin levels in inflammatory acne vulgaris patients and to reveal the possible relation between its serum levels and the insulin resistance status in patients. Patients and Methods The study included 30 patients suffering from inflammatory acne vulgaris and 30 healthy control subjects. Full general and dermatological examination were performed, recording of BMI, GAGS score was done. Then, measurement of fasting insulin and fasting glucose was performed to calculate HOMAIR. Measurement of serum visfatin was done using ELISA. Results Serum visfatin and HOMAIR levels were significantly higher in acne patients compared to control subjects. Serum visfatin and HOMAIR provided significant discriminative power to differentiate acne patients from control subjetcs.

Evaluation of Serum Lipocalin-2 Level and Its Relation to Insulin Resistance in Patients with Inflammatory Acne Vulgaris

Abstract Introduction Acne vulgaris is a common chronic inflammatory disease of the pilosebaceous unit. It is characterized by the formation of non-inflammatory comedones and inflammatory papules, pustules, nodules and cysts. Lipocalin-2 (LCN2) is an attractive biomarker of inflammation, ischemia, infection, and kidney damage. Aim of the Study The current study aimed to evaluate serum Lipocalin-2 levels in inflammatory acne vulgaris patients and to reveal the possible relation between its serum levels and the insulin resistance status in acne patients. Patients and Methods The study included 60 patients suffering from inflammatory acne vulgaris and 60 healthy control subjects. Full general and dermatological examination were performed, recording of BMI, GAGS score was done. Then, measurement of fasting insulin and fasting glucose was performed to calculate HOMA-IR. Results Serum lipocalin-2, fasting insulin and HOMA-IR levels were significantly higher in acne patients compared to control subjects. Conclusion Inflammatory acne vulgaris patients have higher levels of serum lipocalin-2 which might be related to acne pathogenesis.

Hydrogen Sulfide Regulates Glucose Uptake in Skeletal Muscles via S-Sulfhydration of AMPK in Muscle Fiber Type-Dependent Way

BackgroundThe effect of hydrogen sulfide (H2S) on glucose homeostasis remains to be elucidated, especially in the state of insulin resistance. ObjectivesIn the present study, we aimed to investigate H2S-regulated glucose uptake in the M. pectoralis major (PM) muscle (which mainly consists of fast-twitch glycolytic fibers) and M. biceps femoris (BF) muscle (which mainly consists of slow-twitch oxidative fibers) of the chicken, a potential model of insulin resistance. MethodsChicks were subjected to intraperitoneal injection of sodium hydrosulfide (NaHS, 50 μmol/kg body mass/day) twice a day to explore glucose homeostasis. In vitro, myoblasts from PM and BF muscles were used to detect glucose uptake and utilization. Effects of AMP-activated protein kinase (AMPK) phosphorylation, AMPK S-sulfhydration, and mitogen-activated protein kinase (MAPK) pathway induction by NaHS were detected. ResultsNaHS enhanced glucose uptake and utilization in chicks (P < 0.05). In myoblasts from PM muscle, NaHS (100 μM) increased glucose uptake by activating AMPK S-sulfhydration, AMPK phosphorylation, and the AMPK/p38 MAPK pathway (P < 0.05). However, NaHS decreased glucose uptake in myoblasts from BF muscle by suppressing the p38 MAPK pathway (P < 0.05). Moreover, NaHS increased S-sulfhydration and, in turn, the phosphorylation of AMPK (P < 0.05). ConclusionsThis study reveals the role of H2S in enhancing glucose uptake and utilization in chicks. The results suggest that NaHS is involved in glucose uptake in skeletal muscle in a fiber type-dependent way. The AMPK/p38 pathway and protein S-sulfhydration promote glucose uptake in fast-twitch glycolytic muscle fibers, which provides a muscle fiber-specific potential therapeutic target to ameliorate glucose metabolism.

Insulin resistance surrogate markers and risk of hyperuricemia among patients with and without coronary artery disease: a cross-sectional study.

Although emerging evidence emphasizes the associations between both insulin resistance and hyperuricemia with coronary artery disease (CAD) risk, no definite relationship has yet been established. In this respect, time-efficient and affordable methods to estimate insulin resistance (IR) status, and to predict risk of hyperuricemia, are needed. Thus, the goal of this investigation was to examine the associations between IR, as assessed by novel surrogate markers [triglyceride-glucose (TyG) and TyG-body mass index (TyG-BMI)], and risk of hyperuricemia in patients with and without diagnosed CAD. This cross-sectional study used data from the medical records of 1,170 patients who were referred to the cardiology outpatient clinic. Medical records, anthropometrics, and serum analytes were determined at the initial visit. Hyperuricemia was defined as serum uric acid ≥ 5.6 mg/dL. IR was estimated through surrogate markers (TyG and TyG-BMI). Multiple regression analysis was performed to assess the relationship between these indices and odds of hyperuricemia among patients with and without CAD. Overall, 814 angiographically-confirmed CAD cases (mean age (SD) = 52 (8)yrs) were compared with 356 patients without CAD (mean age (SD) = 48 (8)yr). There were positive associations between TyG and TyG-BMI indices and odds of hyperuricemia in CAD patients after controlling for confounders (adjusted odds ratio (aOR) = 1.60; 95%CI: 1.02-2.51; p-value = 0.036; and aOR = 1.83; 95%CI: 1.24-2.70; p-value = 0.002, third tertiles for TYG and TYG-BMI, respectively). The present findings suggest that higher levels of the IR surrogate markers, TyG and TyG-BMI, are associated with higher odds of hyperuricemia in patients with CAD. However, given the cross-sectional design of this study, the sensitivity and specificity of these novel markers could not be determined for confirming the diagnosis of IR and hyperuricemia, further studies are needed to determine such outcomes and to confirm the current findings.

Rapid gastric emptying during pregnancy in a rat model

Background/aimsThe effect of pregnancy on gastric emptying has not been established, although the predominant clinical assumption is that gastric emptying is delayed during pregnancy. We hypothesized that the rate of emptying of nutrients during pregnancy is not delayed, but is actually more rapid when compared to the non-pregnant state. The rate of gastric emptying is a major determinant of postprandial glucose elevations. Materials and methods24 female and 4 male Spague-Dawley rats were used. Female rats were randomly divided into two groups: eight rats for the control group and sixteen rats for the pregnant group. Using physiologic, non-traumatic nuclear medicine scintigraphy imaging methodology, the authors studied gastric emptying of a liquid mixed meal in pregnant rats and non-pregnant controls. Body weights, daily food ingestion, and the rate of nutrient gastric emptying were recorded in both groups at pre-pregnancy, early pregnancy, and late pregnancy. ResultsThe authors found that pregnancy in this rat model is associated with a 37–43% increased rate of nutrient gastric emptying from the stomach in late pregnancy as compared to non-pregnant control rats and pre-pregnancy rats. ConclusionThese findings contradict the current clinical assumption that gastric emptying is delayed in pregnancy. If further studies confirm a more rapid gastric emptying rate during human pregnancy, new therapies aimed at slowing the rate of nutrient absorption should be considered for the prevention and treatment of pregnancy-associated nausea, gestational diabetes, and other insulin-resistant pregnancy-associated states such as pre-eclampsia.

Pengaruh Pemberian Sari Ketela Ungu (Ipomea Batatas L.) Terhadap Kadar Insulin Tikus Wistar Bunting Model DMG

Background : Gestational Diabetes Mellitus is a complication of pregnancy in mothers without a previous diagnosis of diabetes, then chronic hyperglycemia is detected during pregnancy. Generally, this hyperglycemia is caused by impaired glucose tolerance due to pancreatic cell dysfunction, which begins with chronic insulin resistance conditions. The prevalence of GDM in Southeast Asia is 10%, while the overall diagnosis of diabetes in women in Indonesia is 1.8%. Nowadays, antioxidant therapy is being developed to treat DMG, one of which is the use of purple cassava plants.Objective : to determine the effect of purple cassava juice (Ipomea Batatas L.) on increasing insulin levels of wistar rats model of gestational diabetes mellitus. Methode : This study used an experimental method which was designed with the Post Test Only Group Design method. The total number of samples used in this study was 30 rats which were divided into 5 groups. Furthermore, the treatment group was given STZ injection of 45 mg/KgBB and then given purple cassava juice therapy for 14 days. Next, blood samples were tested for insulin levels using the ELISA Rat Kit. Result : There are no differences of insulin level between the treatment group and the control group because they had constant result. Conclusion : In this study, it was not found that there was an increase in insulin levels after treatment of purple yam juice for 14 days. So the research hypothesis was rejected. Keyword : Diabetes Mellitus Gestasional, Insulin Levels, Wistar Rats, Purple Yam Juice.

Analysis of Cell Glycogen with Quantitation and Determination of Branching Using Liquid Chromatography-Mass Spectrometry.

Glycogen is a highly branched biomacromolecule that functions as a glucose buffer. It is involved in multiple diseases such as glycogen storage disorders, diabetes, and even liver cancer, where the imbalance between biosynthetic and catabolic enzymes results in structural alterations and abnormal accumulation of glycogen that can be toxic to cells. Accurate and sensitive glycogen quantification and structural determination are prerequisites for understanding the phenotypes and biological functions of glycogen under these conditions. In this research, we furthered cell glycogen characterization by presenting a highly sensitive method to measure the glycogen content and degree of branching. The method employed a novel fructose density gradient as an alternative to the traditional sucrose gradient to fractionate glycogen from cell mixtures using ultracentrifugation. Fructose was used to avoid the large glucose background, allowing the method to be highly quantitative. The glycogen content was determined by quantifying 1-phenyl-3-methyl-5-pyrazolone (PMP)-derivatized glucose residues obtained from acid-hydrolyzed glycogen using ultra-high-performance liquid chromatography/triple quadrupole mass spectrometry (UHPLC/QqQ-MS). The degree of branching was determined through linkage analysis where the glycogen underwent permethylation, hydrolysis, PMP derivatization, and UHPLC/QqQ-MS analysis. The new approach was used to study the effect of insulin on the glycogen phenotypes of human hepatocellular carcinoma (Hep G2) cells. We observed that cells produced greater amounts of glycogen with less branching under increasing insulin levels before reaching the cell's insulin-resistant state, where the trend reversed and the cells produced less but higher-branched glycogen. The advantage of this method lies in its high sensitivity in characterizing both the glycogen level and the structure of biological samples.

Insulin Resistance Is Associated With Reduced Capillary Permeability of Thigh Muscles in Patients With Type 2 Diabetes.

Insulin-mediated microvascular permeability and blood flow of skeletal muscle appears to be altered in the condition of insulin resistance. Previous studies on this effect used invasive procedures in humans or animals. The aim of this study was to demonstrate the feasibility of a noninvasive assessment of human muscle microcirculation via dynamic contrast-enhanced (DCE)-magnetic resonance imaging (MRI) of skeletal muscle in patients with type 2 diabetes (T2D). A total of 56 participants (46 with T2D, 10 healthy controls [HC]) underwent DCE-MRI of the right thigh at 3 Tesla. The constant of the musculature's microvascular permeability (Ktrans), extravascular extracellular volume fraction (ve), and plasma volume fraction (vp) were calculated. In T2D patients, skeletal muscle Ktrans was lower (HC 0.0677 ± 0.002 min-1, T2D 0.0664 ± 0.002 min-1; P = 0.042) while the homeostasis model assessment (HOMA) index was higher in patients with T2D compared to HC (HC 2.72 ± 2.2, T2D 6.11 ± 6.2; P = .011). In T2D, Ktrans correlated negatively with insulin (r = -0.39, P = .018) and HOMA index (r = -0.38, P = .020). The results signify that skeletal muscle DCE-MRI can be employed as a noninvasive technique for the assessment of muscle microcirculation in T2D. Our findings suggest that microvascular permeability of skeletal muscle is lowered in patients with T2D and that a decrease in microvascular permeability is associated with insulin resistance. These results are of interest with regard to the impact of muscle perfusion on diabetic complications such as diabetic sarcopenia.

Phosphorylation of insulin receptor substrates (IRS-1 and IRS-2) is attenuated following cecal ligation and puncture in mice

BackgroundSepsis is characterized as an insulin resistant state. However, the effects of sepsis on insulin’s signal transduction pathway are unknown. The molecular activity driving insulin signaling is controlled by tyrosine phosphorylation of the insulin receptor β-subunit (IRβ) and of insulin receptor substrate molecules (IRS) -1 and IRS-2.HypothesisCecal ligation and puncture (CLP) attenuates IRβ, IRS-1 and IRS-2 phosphorylation.MethodsIACUC-approved studies conformed to ARRIVE guidelines. CLP was performed on C57BL/6 mice; separate cohorts received intraperitoneal insulin at baseline (T0) or at 23 or 47 h. post-CLP, 1 h before mice were euthanized. We measured levels of (1) glucose and insulin in serum, (2) IRβ, IRS-1 and IRS-2 in skeletal muscle and liver homogenate and (3) phospho-Irβ (pIRβ) in liver and skeletal muscle, phospho-IRS-1 (pIRS-1) in skeletal muscle and pIRS-2 in liver. Statistical significance was determined using ANOVA with Sidak’s post-hoc correction.ResultsCLP did not affect the concentrations of IRβ, IRS-1or IRS-2 in muscle or liver homogenate or of IRS-1 in liver. Muscle IRS-1 concentration at 48 h. post-CLP was higher than at T0. Post-CLP pIRS-1 levels in muscle and pIRβ and pIRS-2 levels in liver were indistinguishable from T0 levels. At 48 h. post-CLP pIRβ levels in muscle were higher than at T0. Following insulin administration, the relative abundance of pIRβ in muscle and liver at T0 and at both post-CLP time points was significantly higher than abundance in untreated controls. In T0 controls, the relative abundance of pIRS-1 in muscle and of pIRS-2 in liver following insulin administration was higher than in untreated mice. However, at both post-CLP time points, the relative abundance of pIRS-1 in muscle and of pIRS-2 in liver following insulin administration was not distinguishable from the abundance in untreated mice at the same time point. Serum glucose concentration was significantly lower than T0 at 24 h., but not 48 h., post-CLP. Glucose concentration was lower following insulin administration to T0 mice but not in post-CLP animals. Serum insulin levels were significantly higher than baseline at both post-CLP time points.ConclusionsCLP impaired insulin-induced tyrosine phosphorylation of both IRS-1 in muscle and IRS-2 in liver. These findings suggest that the molecular mechanism underlying CLP-induced insulin resistance involves impaired IRS-1/IRS-2 phosphorylation.

Calcium handling coupled to the endothelin ETA and ETB receptor-mediated vasoconstriction in resistance arteries: Differential regulation by PI3K, PKC and RhoK

Abnormal endothelin-1 (ET-1) activity is involved in the pathogenesis of vascular diseases such as essential and pulmonary arterial hypertension, coronary artery disease, and cerebrovascular disease, blockade of ET receptors having shown efficacy in clinical assays and experimental models of hypertension. Augmented Ca2+ influx and changes in Ca2+ sensitization associated with arterial vasoconstriction underlie increased systemic vascular resistance in hypertension. Since peripheral resistance arteries play a key role in blood pressure regulation, we aimed to determine here the specific Ca2+ signaling mechanisms linked to the ET receptor-mediated vasoconstriction in resistance arteries and their selective regulation by protein kinase C (PKC), Rho kinase (RhoK), the phosphatidylinositol 3-kinase (PI3K) and the mitogen-activated protein kinase (MAPK). ET-1-induced contraction was mediated by the endothelin ETA receptor with a minor contribution of vascular smooth muscle (VSM) endothelin ETB receptors. ET receptor activation elicited Ca2+ mobilization from intracellular stores, extracellular Ca2+ influx and Ca2+ sensitization associated with contraction in resistance arteries. Vasoconstriction induced by ET-1 was largely dependent on activation of canonical transient receptor potential channel 3 (TRPC3) and extracellular Ca2+ influx through nifedipine-sensitive voltage-dependent Ca2+ channels. PI3K inhibition reduced intracellular Ca2+ mobilization and Ca2+ entry without altering vasoconstriction elicited by ET-1, while PKC has dual opposite actions by enhancing Ca2+ influx associated with contraction, and by inhibiting Ca2+ release from intracellular stores. RhoK was a major determinant of the enhanced sensitivity of the contractile filaments underlying ET-1 vasoconstriction, with also a modulatory positive action on Ca2+ influx and intracellular Ca2+ release. Augmented RhoK and PKC activities are involved in vascular dysfunction in hypertension and vascular complications of insulin-resistant states, and these kinases are thus potential pharmacological targets in vascular diseases in which the ET pathway is impaired.