Assessment of Insulin Resistance in Subjects with Normal Glucose Tolerance, Hyperinsulinemia with Normal Blood Glucose Tolerance, Impaired Glucose Tolerance, and Newly Diagnosed Type 2 Diabetes (Prediabetes Insulin Resistance Research)

Young adult male LEW.1WR1 rats have reduced beta cell area and develop glucose intolerance

Prediabetes affects 1 in 3 American adults and is characterized by insulin resistance, insulin hypersecretion, and impaired glucose tolerance. Weanling LEW.1WR1 (1WR1) rats have increased blood insulin concentrations, so we hypothesized that young adult 1WR1 rats would develop impaired glucose tolerance due to the poor regulation of insulin. We monitored glucose tolerance, insulin tolerance, and weight gain for 10 weeks to assess if there was a decline in glucose processing over time. 1WR1 rats were significantly more glucose intolerant after 8 weeks. 1WR1 rats had increased body mass, yet abdominal fat mass was not significantly increased. Although the 1WR1 rats had increased circulating insulin and glucagon protein levels, 1WR1 rat beta cell area was significantly reduced. There may be underlying insulin resistance as evidenced by dysfunctional insulin regulation during fasting. Understanding the metabolic phenotype of this rat model can provide insight into the human pathophysiological changes that increase susceptibility to glucose intolerance and prediabetes.

Effects on cardiometabolic risk factors after reduction of artificially sweetened beverage consumption in overweight subjects. A randomised controlled trial

BACKGROUND

The consumption of artificially sweetened beverages (ASBs) has been linked to metabolic alterations. The effect of reducing the regular consumption of these beverages on the metabolism is currently unknown.

OBJECTIVE

To evaluate the effect of reducing consumption of ASBs on the metabolism in overweight young adults.

DESIGN

A randomised, single-blind, controlled, 12-week, clinical trial was performed in overweight young adults who regularly consume ASBs. The 45 subjects who participated in the study were randomly divided into two groups: (1) control group (n=21) and (2) intervention group (no intake of ASBs, n=24). Body weight and composition, fasting plasma concentrations of glucose, triglycerides, insulin, cholesterol, low-density lipoproteins and high-density lipoproteins were measured at the beginning and end of the study. and the HOMA-IR was calculated.

RESULTS

At the end of 12 weeks, the intervention group showed a significant decrease (as opposed to an increase in the control group) in the percentage of change in body weight (-1.22% vs 1.31%, p<0.004), body fat (-6.28% vs 6.15%, p<0.001) and insulin resistance index (-12.06 vs 38.21%, p<0.00002), as well as in levels of glucose (-4.26% vs 0.51%, p<0.05), triglycerides (-14.74% vs 19.90%, p<0.006), insulin (-8.02% vs 39.23%, p<0.00005), cholesterol (-8.71% vs 0.77%, p<0.01) and LDL (-9.46% vs 9.92%, p<0.004).

CONCLUSION

A reduction in habitual consumption of ASBs in overweight young adults decreases biochemical measurements, body weight and composition, suggesting a participation in the metabolic processes.

Insulin sensitizes neural and vascular TRPV1 receptors in the trigeminovascular system

Background

Clinical observations suggest that hyperinsulinemia and insulin resistance can be associated with migraine headache. In the present study we examined the effect of insulin on transient receptor potential vanilloid 1 (TRPV1) receptor-dependent meningeal nociceptor functions in rats.

Methods

The effects of insulin on the TRPV1 receptor stimulation-induced release of calcitonin gene related peptide (CGRP) from trigeminal afferents and changes in meningeal blood flow were studied. Colocalization of the insulin receptor, the TRPV1 receptor and CGRP was also analyzed in trigeminal ganglion neurons.

Results

Insulin induced release of CGRP from meningeal afferents and consequent increases in dural blood flow through the activation of TRPV1 receptors of trigeminal afferents. Insulin sensitized both neural and vascular TRPV1 receptors making them more susceptible to the receptor agonist capsaicin. Immunohistochemistry revealed colocalization of the insulin receptor with the TRPV1 receptor and CGRP in a significant proportion of trigeminal ganglion neurons.

Conclusions

Insulin may activate or sensitize meningeal nociceptors that may lead to enhanced headache susceptibility in persons with increased plasma insulin concentration.

A prescription for exercise in systemic lupus erythematosus

Patients with systemic lupus erythematosus (SLE) have increased cardiovascular risk, and fatigue is a major subjective complaint. Sedentary lifestyle has been shown to have negative health impacts in cardiovascular and rheumatic disease, though exercise has not traditionally been incorporated into routine therapy recommendations. Regular exercise in SLE may improve difficult to treat Type 2 symptoms, such as fatigue, depression, stress, and quality of life. Insufficient counseling on exercise by physicians is a notable barrier for SLE patients to engage in physical activity. Aerobic exercise regimens are more commonly studied, and have been shown to improve cardiovascular health in SLE. Exercise may improve some inflammatory markers, though does not definitively affect SLE clinical disease activity. Physical activity should be recommended to improve quality of life and cardiovascular health in patients with SLE. Developing clearer guidelines for exercise regimens in a patient-centered manner is warranted, especially given diverse phenotypes of SLE patients and varying degrees of physical limitations.

Consuming Sucrose- or HFCS-sweetened Beverages Increases Hepatic Lipid and Decreases Insulin Sensitivity in Adults

CONTEXT

Studies in rodents and humans suggest that high-fructose corn syrup (HFCS)-sweetened diets promote greater metabolic dysfunction than sucrose-sweetened diets.

OBJECTIVE

To compare the effects of consuming sucrose-sweetened beverage (SB), HFCS-SB, or a control beverage sweetened with aspartame on metabolic outcomes in humans.

METHODS

A parallel, double-blinded, NIH-funded study. Experimental procedures were conducted during 3.5 days of inpatient residence with controlled feeding at a research clinic before (baseline) and after a 12-day outpatient intervention period. Seventy-five adults (18-40 years) were assigned to beverage groups matched for sex, body mass index (18-35 kg/m2), and fasting triglyceride, lipoprotein and insulin concentrations. The intervention was 3 servings/day of sucrose- or HFCS-SB providing 25% of energy requirement or aspartame-SB, consumed for 16 days. Main outcome measures were %hepatic lipid, Matsuda insulin sensitivity index (ISI), and Predicted M ISI.

RESULTS

Sucrose-SB increased %hepatic lipid (absolute change: 0.6 ± 0.2%) compared with aspartame-SB (-0.2 ± 0.2%, P < 0.05) and compared with baseline (P < 0.001). HFCS-SB increased %hepatic lipid compared with baseline (0.4 ± 0.2%, P < 0.05). Compared with aspartame-SB, Matsuda ISI decreased after consumption of HFCS- (P < 0.01) and sucrose-SB (P < 0.01), and Predicted M ISI decreased after consumption of HFCS-SB (P < 0.05). Sucrose- and HFCS-SB increased plasma concentrations of lipids, lipoproteins, and uric acid compared with aspartame-SB. No outcomes were differentially affected by sucrose- compared with HFCS-SB. Beverage group effects remained significant when analyses were adjusted for changes in body weight.

CONCLUSION

Consumption of both sucrose- and HFCS-SB induced detrimental changes in hepatic lipid, insulin sensitivity, and circulating lipids, lipoproteins and uric acid in 2 weeks.

Effects on cardiometabolic risk factors after reduction of artificially sweetened beverage consumption in overweight subjects. A randomised controlled trial

BACKGROUND

The consumption of artificially sweetened beverages (ASBs) has been linked to metabolic alterations. The effect of reducing the regular consumption of these beverages on the metabolism is currently unknown.

OBJECTIVE

To evaluate the effect of reducing consumption of ASBs on the metabolism in overweight young adults.

DESIGN

A randomised, single-blind, controlled, 12-week, clinical trial was performed in overweight young adults who regularly consume ASBs. The 45 subjects who participated in the study were randomly divided into two groups: (1) control group (n=21) and (2) intervention group (no intake of ASBs, n=24). Body weight and composition, fasting plasma concentrations of glucose, triglycerides, insulin, cholesterol, low-density lipoproteins and high-density lipoproteins were measured at the beginning and end of the study. and the HOMA-IR was calculated.

RESULTS

At the end of 12 weeks, the intervention group showed a significant decrease (as opposed to an increase in the control group) in the percentage of change in body weight (-1.22% vs 1.31%, p<0.004), body fat (-6.28% vs 6.15%, p<0.001) and insulin resistance index (-12.06 vs 38.21%, p<0.00002), as well as in levels of glucose (-4.26% vs 0.51%, p<0.05), triglycerides (-14.74% vs 19.90%, p<0.006), insulin (-8.02% vs 39.23%, p<0.00005), cholesterol (-8.71% vs 0.77%, p<0.01) and LDL (-9.46% vs 9.92%, p<0.004).

CONCLUSION

A reduction in habitual consumption of ASBs in overweight young adults decreases biochemical measurements, body weight and composition, suggesting a participation in the metabolic processes.

Metabolic Parameters in Patients with Suspected Reactive Hypoglycemia

Background: It remains unclear whether reactive hypoglycemia (RH) is a disorder caused by improper insulin secretion, result of eating habits that are not nutritionally balanced or whether it is a psychosomatic disorder. The aim of this study was to investigate metabolic parameters in patients admitted to the hospital with suspected RH. Methods: The study group (SG) included non-diabetic individuals with symptoms consistent with RH. The control group (CG) included individuals without hypoglycemic symptoms and any documented medical history of metabolic disorders. In both groups the following investigations were performed: fasting glucose and insulin levels, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), 75 g five-hour Oral Glucose Tolerance Test (OGTT) with an assessment of glucose and insulin and lipid profile evaluation. Additionally, Mixed Meal Tolerance Test (MMTT) was performed in SG. Results from OGTT and MMTT were analyzed in line with the non-standardized RH diagnostic criteria. Results: Forty subjects have been enrolled into SG. Twelve (30%) of those patients had hypoglycemic symptoms and glucose level ≤55 mg/dL during five-hour OGTT and have been diagnosed with RH. Ten (25%) subjects manifested hypoglycemic like symptoms without significant glucose decline. Patients with diagnosed RH had statistically significantly lower mean glucose at first (92.1 ± 37.9 mg/dL vs. 126.4 ± 32.5 mg/dL; LSD test: p < 0.001) and second (65.6 ± 19.3 mg/dL vs. 92.6 ± 19.3 mg/dL; LSD test: p < 0.001) hour of OGTT and insulin value (22.7 ± 10.9 lU/mL vs. 43.4 ± 35.0 lU/mL; LSD test: p < 0.001) at second hour of OGTT compared to the patients who did not meet the criteria of RH. Seventeen (43%) subjects from SG reported symptoms suggesting hypoglycemia during MMTT but none of them had glucose value lower than ≤55 mg/dL (68.7 ± 4.7 mg/dL). From the entire lipid profile, only mean total cholesterol value was significantly higher (p = 0.024) in SG in comparison with CG but did not exceed standard reference range. Conclusions: No metabolic disturbances have been observed in patients with diagnosed reactive hypoglycemia. Hyperinsulinemia has not been associated with glycemic declines in patients with this condition. Occurrence of pseudohypoglicemic symptoms and lower glucose value was more common after ingestion of glucose itself rather than after ingestion of a balanced meal. This could suggest an important role that nutritionally balanced diet may play in maintaining correct glucose and insulin levels in the postprandial period.

Comparable metabolic effects of isocaloric sucrose and glucose solutions in rats

Much of the global increase in sugar intake is attributable to rising consumption of sugar-sweetened beverages (SSBs). Because people compensate poorly for liquid calories, SSB consumption increases total energy intake, raising the risk of harmful metabolic effects in addition to possible effects of sugars per se. Glucose and fructose, the constituent sugars in sucrose, can exert distinct effects on metabolism and also differ in their satiating properties, suggesting that compensation for the calories in these sugars may also vary. In light of claims that the fructose within sucrose is particularly harmful, the present study compared the effects of giving rats access to either a sucrose or an isoenergetic glucose solution. Adult male rats were fed standard chow and water supplemented with 95 ml of 10% glucose (Glucose group; n = 10), 9% sucrose solution (Sucrose group; n = 10) or water only (Control group; n = 10) daily for 7 weeks. Sugar-fed groups had higher total energy intakes than the Control group, but the extent of this incomplete compensation did not vary between Sucrose and Glucose groups. In a short-term compensation test, sugar groups were less sensitive to the effects of a sweet pre-meal, with no differences between the Glucose and Sucrose groups. Relative to water, both sugars reduced insulin sensitivity after 4 weeks on the diets and elevated fat mass at 7 weeks. Results suggest that sucrose and glucose induce comparable metabolic impairments and alter the homeostatic regulation of food intake even under conditions where daily access is capped.

Aqueous extract from Pepino (Solanum muricatum Ait.) leaves ameliorated insulin resistance, hyperlipidemia, and hyperglycemia in mice with metabolic syndrome

Solanum muricatum Ait. (Pepino) is a plant food commonly cultivated in the Penghu Island, Taiwan. This present study aimed to investigate the protective effects of aqueous extract of Pepino leaves (AEPL) in mice with metabolic syndrome. Metabolic syndrome animal model was induced by continuous high-fat diet feeding and low-dose streptozotocin (40 mg/ml) for 5 days. A 1% AEPL or metformin were given for 6 weeks after streptozotocin injection. The results revealed that 1% AEPL effectively reduced fasting blood glucose, insulin resistance, and hyperlipidemia in metabolic syndrome mice. Histologic examination revealed lipid accumulation in liver decreased by 1% AEPL treatment. Further, western blot analysis revealed 1% AEPL treatment managed enzymes related to lipid synthesis and oxidation pathways and hepatic glucose production. Besides, 1% AEPL treatment increased liver antioxidant activities to against oxidative stress. These results concluded that AEPL treatment attenuated insulin resistance, hyperlipidemia, and hyperglycemia of metabolic syndrome. PRACTICAL APPLICATIONS: Metabolic syndrome (MS) is a multifactorial chronic disease which is characterized by dyslipidemia, insulin resistance, and hyperglycemia. However, there is no single drug or defined medication for MS so far. The present study revealed that AEPL treatment was able to regulate lipid metabolism and glycemic control at the molecular level to alleviate MS. AEPL has the potential to be a novo complementary medication for metabolic syndrome.

Mechanistic Actions of microRNAs in Diabetic Wound Healing

Wound healing is a complex biological process that is impaired under diabetes conditions. Chronic non-healing wounds in diabetes are some of the most expensive healthcare expenditures worldwide. Early diagnosis and efficacious treatment strategies are needed. microRNAs (miRNAs), a class of 18–25 nucleotide long RNAs, are important regulatory molecules involved in gene expression regulation and in the repression of translation, controlling protein expression in health and disease. Recently, miRNAs have emerged as critical players in impaired wound healing and could be targets for potential therapies for non-healing wounds. Here, we review and discuss the mechanistic background of miRNA actions in chronic wounds that can shed the light on their utilization as specific wound healing biomarkers.

DPP-4 inhibition resembles exercise in preventing type 2 diabetes development by inhibiting hepatic protein kinase Cε expression in a mouse model of hyperinsulinemia

OBJECTIVE

Interventions for hyperinsulinemia (HINS), an early indicator of type 2 diabetes mellitus (T2DM), can significantly reduce the T2DM risk. This study aims to determine how dipeptidyl peptidase-4 (DPP-4) inhibition prevents HINS progression to T2DM through ameliorating hepatic steatosis.

METHODS

KKay mice were used as a HINS model and they underwent exercise or received a DPP-4 inhibitor, MK0626. Hepatic steatosis was examined and liver diacylglycerol levels were determined. Human hepatic cells (LO2) were treated with MK0626 or transfected with DPP-4 siRNA. Protein kinase C ε isoform (PKCε) and DPP-4 expression and insulin receptor substrate 1 (IRS-1) phosphorylation were assessed using immunohistochemistry and western blot.

RESULTS

KKay mice developed HINS spontaneously at 7 weeks of age. Similar to exercise, MK0626 ameliorated hepatic steatosis and reduced the liver triglyceride and diacylglycerol content. Both exercise and MK0626 suppressed diacylglycerol-induced PKCε expression and restored insulin signaling, which was shown by tyrosine phosphorylation of IRS-1, in the livers of KKay mice. Additionally, silencing DPP-4 or MK0626 treatment decreased PKCε expression in LO2 cells.

CONCLUSIONS

Our data demonstrate that DPP-4 inhibition resembles exercise and effectively delays T2DM onset by suppressing hepatic PKCε expression in the HINS mouse model.

Eating Competence Is Associated with Lower Prevalence of Obesity and Better Insulin Sensitivity in Finnish Adults with Increased Risk for Type 2 Diabetes: The StopDia Study

A healthy diet prevents type 2 diabetes but is often difficult to adhere to. This cross-sectional study aimed to investigate whether eating competence is associated with diet or risk factors and prevalence of type 2 diabetes in individuals screened for type 2 diabetes risk. Eating competence is an indicator of food acceptance, positive attitudes, internal regulation and contextual skills related to food and eating. In total, 3147 Finnish adults aged 18-74 at an increased risk for type 2 diabetes identified via online risk screening participated in the baseline examinations of the Stop Diabetes (StopDia) study. The participants filled out the digital questionnaire on food intake, physical activity and sleep, and the Satter Eating Competence Inventory 2.0^TM (ecSI 2.0^TM). In addition, anthropometric and laboratory measurements were performed at primary healthcare centres. Eating competent individuals (37%, classified by ecSI 2.0^TM) had a better quality of diet (p < 0.05 for all). Additionally, eating competence was associated with a lower prevalence of previously undiagnosed type 2 diabetes, abdominal obesity, metabolic syndrome and hypertriglyceridaemia, and with better insulin sensitivity (p < 0.05 for all). However, these associations, except for metabolic syndrome, were at least partly mediated by body mass index. Eating competence is associated with a healthy diet and could, thus, in the long term, support the prevention of type 2 diabetes.

High fructose-containing drinking water-induced steatohepatitis in rats is prevented by the nicotinamide-mediated modulation of redox homeostasis and NADPH-producing enzymes

An imbalance in the redox state, increased levels of lipid precursors and overactivation of de novo lipogenesis determine the development of fibrosis during nonalcoholic steatohepatitis (NASH). We evaluated the modulation of NADPH-producing enzymes associated with the antifibrotic, antioxidant and antilipemic effects of nicotinamide (NAM) in a model of NASH induced by excess fructose consumption. Male rats were provided drinking water containing 40% fructose for 16 weeks. During the last 12 weeks of fructose administration, water containing NAM was provided to some of the rats for 5 h/day. The biochemical profiles and the ghrelin, leptin, lipoperoxidation and TNF-α levels in serum and the glucose-6-phosphate dehydrogenase (G6PD), malic enzyme (ME) and NADP⁺-dependent isocitric dehydrogenase (IDP) levels, the reduced/oxidized glutathione (GSH/GSSG) and reduced/oxidized nicotinamide adenine dinucleotide (phosphate) (NAD(P)H/NAD(P)⁺) ratios, and the levels of various lipogenic and fibrotic markers in the liver were evaluated. The results showed that hepatic fibrosis induced by fructose consumption was associated with weight gain, hunger-satiety system dysregulation, hyperinsulinemia, dyslipidemia, lipoperoxidation and inflammation. Moreover, increased levels of hepatic G6PD and ME activity and expression, the NAD(P)H/NAD(P)⁺ ratios, and GSSG concentration and increased expression of lipogenic and fibrotic markers were detected, and these alterations were attenuated by NAM administration. Specifically, NAM diminished the activity and expression of G6PD and ME, and this effect was associated with a decrease in the NADPH/NADP⁺ ratios, increased GSH levels and decreased lipoperoxidation and inflammation, ameliorating fibrosis and NASH development. NAM reduces liver steatosis and fibrosis by regulating redox homeostasis through a G6PD- and ME-dependent mechanism.

Oxidative Stress, Intrauterine Growth Restriction, and Developmental Programming of Type 2 Diabetes

Intrauterine growth restriction (IUGR) leads to reduced birth weight and the development of metabolic diseases such as Type 2 diabetes in adulthood. Mitochondria dysfunction and oxidative stress are commonly found in key tissues (pancreatic islets, liver, and skeletal muscle) of IUGR individuals. In this review, we explore the role of oxidative stress in IUGR-associated diabetes etiology.

Assessment of insulin sensitivity and secretion in patients with fibrocalculous pancreatic diabetes

Background: Fibrocalculous pancreatic diabetes (FCPD) is a secondary form of diabetes seen in patients with tropical chronic pancreatitis. Insulin deficiency plays a major role in the etiopathogenesis of FCPD. Limited data suggest a possible role of insulin resistance (IR) in the pathogenesis of FCPD. Sparse data exist on measures of insulin sensitivity (IS) and secretion in patients with FCPD and its comparison to type 2 diabetes mellitus (T2D) patients. Method: Eighty patients with FCPD, 36 patients with T2D and 36 healthy subjects were included. A 75 g oral glucose tolerance test (OGTT) was performed in the morning after an overnight fast. We evaluated IS and secretion using indices derived from fasting (homeostasis model assessment of insulin resistance [HOMA-IR], quantitative insulin sensitivity check index [QUICKI] and homeostasis model assessment of beta-cell function [HOMA-ß]) and OGTT (Matsuda, insulin sensitivity index by Kanauchi [ISI-K], oral glucose insulin sensitivity index [OGIS], Stumvoll, insulinogenic index and oral disposition index [ODI]) measurements of glucose and insulin. Results: HOMA-IR was significantly higher and QUICKI significantly lower in patients with FCPD and T2D than in healthy controls (P<0.001). Matsuda, ISI-K, OGIS and Stumvoll were significantly lower in patients with FCPD and T2D than in healthy controls (P<0.001), indicating reduced IS in both FCPD and T2D patients. HOMA-ß, insulinogenic index and ODI were significantly lower in patients with FCPD and T2D compared to healthy controls (P<0.001). Conclusion: FCPD is associated with reduced IS as assessed by fasting and OGTT-based indices. FCPD is also associated with a greater degree of impairment in insulin secretion than in T2D. IR may play a role in the pathogenesis of FCPD.

Women with COPD by biomass show different serum profile of adipokines, incretins, and peptide hormones than smokers

Background

The main causes of COPD are tobacco smoking (COPD-TS) and biomass smoke exposure (COPD-BS). COPD-TS is known to induce changes in adipokines, incretins, and peptide hormones, frequent biomarkers of inflammation; however, it is unknown if similar changes occur in COPD-BS.

Methods

Clinical and physiological characteristics, and serum concentration of C-peptide, ghrelin, GIP, GLP-1, glucagon, insulin, leptin, PAI-1, resistin, and visfatin were measured in women with COPD-BS, COPD-TS, and healthy controls.

Data were compared with one-way ANOVA and Tukey’s post hoc test; nonparametric were expressed as median (interquartile ranges), with Kruskal-Wallis and Dunn’s post-hoc test. Multivariate analysis, age, BMI, MS, and FEV₁% pred with levels of inflammatory mediators in COPD women.

Results

FEV1% pred, FVC% pred, and FEV1/FVC ratio were decremented in COPD. In COPD-TS increased C-peptide, ghrelin, GIP, GLP-1, and leptin, and reduced glucagon, PAI-1, resistin, and visfatin. In COPD-BS enlarged ghrelin, insulin, leptin, and PAI-1 comparatively with COPD-TS and control, while C-peptide and GLP-1 relatively with controls; conversely, glucagon, and resistin were reduced. Multivariate analysis showed association of ghrelin, insulin, PAI-1, and visfatin with BS exposure.

Conclusions

women with COPD-BS have a distinct profile of adipokines, incretins, and peptide hormones, and specifically with ghrelin, insulin, PAI-1, and visfatin related to BS exposure.

Therapy to Obese Type 2 Diabetes Mellitus: How Far Will We Go Down the Wrong Road?

Traditional glucose-lowering chemical agents, including various types of insulin and insulin secretagogues, insulin sensitizers, gliptins, etc., are based on diabetic pathogenesis of insulin resistance (IR) and islet insufficiency. Numerous evidence-based medical studies have shown that these traditional hypoglycemic chemical agents do not provide cardiovascular benefit to patients with type 2 diabetes mellitus (T2DM) and may even increase the risk of all-cause mortality. Based on research evidence published to date, these studies show that overload of energy could increase the incidence and prevalence of T2DM, and reduction in the heat load can significantly reduce the incidence of T2DM. Therefore, the essence of T2DM is heat overload, meaning heat overload is the etiology of obese T2DM. At the same time, results of numerous studies show that heat overloading is the cause of IR. IR and islet dysfunction are protective factors in intervening with heat overload. These drugs, which are based on the mechanisms of IR and islet insufficiency, increase caloric reserve and cause or worsen obesity, which is equivalent to exacerbating the basic etiology and the cardiovascular risk factor of T2DM. Thus, a reasonable strategy for prevention and treatment of obese T2DM appears to promote the negative balance of calories and the elimination of caloric reserves. Chinese herbal medicines can promote negative balance of heat in many aspects, which can bring new hope for prevention and treatment of T2DM.

Different lipid profiles, insulin sensitivity, and insulin resistance among Han, Uygur, and Kazak men with normal glucose tolerance in Xinjiang, China

Background

This study aimed to determine the differences in clinical parameters among Han, Uygur, and Kazak men with normal glucose tolerance.

Methods

Participants’ data from the China National Diabetes and Metabolic Disorders Study pertaining to Han, Uygur, and Kazak men from the Xinjiang province were used (n = 930). Pearson’s correlation was used to examine the relationship between HOMA-IR, Matsuda Index, and clinical characteristics.

Results

HOMA-IR of Han men was significantly higher than in Uygurs and Kazaks (P < 0.001). The Matsuda Index of Kazaks was significantly higher than that of Hans and Uygurs (P < 0.001). While Kazaks had the highest BMI, WC, SBP, and DBP; they also had the highest HDL-C and lowest TG (P < 0.001). TG of Uygurs was significantly higher than that of Hans and Kazaks (P < 0.001). In Hans and Kazaks, the TG/HDL-C ratio increased with HOMA-IR quartiles; there was no association in Uygurs. In Hans and Kazaks, the TG/HDL-C ratio decreased with Matsuda index quartiles; there was no association in Uygurs. Multivariate linear regression showed that HOMA-IR was independently associated with ethnicity, BMI and TG/HDL-C ratio (P < 0.01), while Matsuda index was independently associated with ethnicity, BMI, LDL-C levels (P < 0.001) and TG/HDL-C ratio (P < 0.001).

Conclusions

In conclusion, Han, Uygur, and Kazak men had different lipid profiles, BMI, and WC. Han men had the highest insulin resistance while Kazak men had the highest insulin sensitivity.

Characteristics of repaglinide and its mechanism of action on insulin secretion in patients with newly diagnosed type-2 diabetes mellitus

This study aims to compare the effect of repaglinide and metformin among Chinese patients with newly diagnosed diabetes, and explore the possible mechanisms by which repaglinide alters insulin secretion.Sixty subjects with glycated hemoglobin (HbA1c) < 10.0% were randomly selected to receive repaglinide or metformin monotherapy for 15 weeks. Blood glucose levels, glycemic variability, β-cell function, and first-phase insulin secretion were compared between these 2 groups at baseline and at 15 weeks. Mouse insulinoma (MIN-6) cells were divided into 3 groups: low glucose, high glucose, and repaglinide 50 nm groups. Cells and cell culture mediums were collected at different timepoints. The expression of pericentrin (PCNT), F-actin, and insulin were tested with immunofluorescence and enzyme-linked immunosorbent assay.All glycemic parameters and variability indexes significantly decreased from baseline to 15 weeks, while no significant difference was found between these 2 groups at baseline or at 15 weeks. Furthermore, there was no significant difference found in fasting insulin and postprandial insulin at baseline and at 15 weeks, while homeostasis model assessment β significantly increased. The first-phase glucose and insulin secretion of the intravenous glucose tolerance test improved in both groups, especially in the repaglinide group. Insulin, PCNT, and F-actin expression in MIN-6 cells decreased after 15 minutes of stimulation with repaglinide, while no difference was observed at 2, 6, and 12 hours. The insulin levels of the cell medium in the repaglinide group remained significantly higher at all timepoints.This study manifests that repaglinide has a noninferiority effect on the glycemic parameters of Chinese patients with newly diagnosed diabetes, when compared with metformin. The PCNT-F-actin pathway plays an important role in the repaglinide regulation process of on-demand insulin secretion.

Exercise Increases Insulin Sensitivity and Skeletal Muscle AMPK Expression in Systemic Lupus Erythematosus: A Randomized Controlled Trial

Systemic lupus erythematosus (SLE) patients may show increased insulin resistance (IR) when compared with their healthy peers. Exercise training has been shown to improve insulin sensitivity in other insulin-resistant populations, but it has never been tested in SLE. Therefore, the aim of the present study was to assess the efficacy of a moderate-intensity exercise training program on insulin sensitivity and potential underlying mechanisms in SLE patients with mild/inactive disease. A 12-week, randomized controlled trial was conducted. Nineteen SLE patients were randomly assigned into two groups: trained (SLE-TR, n = 9) and non-trained (SLE-NT, n = 10). Before and after 12 weeks of the exercise training program, patients underwent a meal test (MT), from which surrogates of insulin sensitivity and beta-cell function were determined. Muscle biopsies were performed after the MT for the assessment of total and membrane GLUT4 and proteins related to insulin signaling [Akt and AMP-activated protein kinase (AMPK)]. SLE-TR showed, when compared with SLE-NT, significant decreases in fasting insulin [−39 vs. +14%, p = 0.009, effect size (ES) = −1.0] and in the insulin response to MT (−23 vs. +21%, p = 0.007, ES = −1.1), homeostasis model assessment IR (−30 vs. +15%, p = 0.005, ES = −1.1), a tendency toward decreased proinsulin response to MT (−19 vs. +6%, p = 0.07, ES = −0.9) and increased glucagon response to MT (+3 vs. −3%, p = 0.09, ES = 0.6), and significant increases in the Matsuda index (+66 vs. −31%, p = 0.004, ES = 0.9) and fasting glucagon (+4 vs. −8%, p = 0.03, ES = 0.7). No significant differences between SLT-TR and SLT-NT were observed in fasting glucose, glucose response to MT, and insulinogenic index (all p > 0.05). SLE-TR showed a significant increase in AMPK Thr 172 phosphorylation when compared to SLE-NT (+73 vs. −12%, p = 0.014, ES = 1.3), whereas no significant differences between groups were observed in Akt Ser 473 phosphorylation, total and membrane GLUT4 expression, and GLUT4 translocation (all p > 0.05). In conclusion, a 12-week moderate-intensity aerobic exercise training program improved insulin sensitivity in SLE patients with mild/inactive disease. This effect appears to be partially mediated by the increased insulin-stimulated skeletal muscle AMPK phosphorylation.

Solid Lipid Nanoparticles of Myricitrin Have Antioxidant and Antidiabetic Effects on Streptozotocin-Nicotinamide-Induced Diabetic Model and Myotube Cell of Male Mouse

Type 2 diabetes mellitus (T2DM) may occur via oxidative stress. Myricitrin is a plant-derived antioxidant, and its solid lipid nanoparticle (SLN) may be more potent. Hence, the present study was conducted to evaluate the effects of myricitrin SLN on streptozotocin-nicotinamide- (STZ-NA-) induced T2DM of the mouse and hyperglycemic myotube. In this experimental study, cold homogenization method was used to prepare SLN. Then, 120 adult male NMRI mice were divided into 7 groups: control, vehicle, diabetes (received STZ 65 mg/kg 15 min after injected NA 120 mg/kg), diabetes + SLN containing myricitrin 1, 3, and 10 mg/kg, and diabetes + metformin. For in vitro study, myoblast (C2C12) cell line was cultured and divided into 6 groups (n = 3): control, hyperglycemia, hyperglycemia + SLN containing myricitrin 1, 3, and, 10 μM, and hyperglycemia + metformin. After the last nanoparticle treatment, plasma samples, pancreas and muscle tissues, and myotubes were taken for experimental assessments. Diabetes increased lipid peroxidation and reduced antioxidant defense along with the hyperglycemia, insulin resistance, and pancreas apoptosis. Hyperglycemia induced oxidative stress, antioxidant impairment, and cellular apoptosis. Myricitrin SLN improved diabetes and hyperglycemia complications in the in vivo and in vitro studies. Therefore, SLN of myricitrin showed antioxidant, antidiabetic, and antiapoptotic effects in the mouse and myotube cells.

Insulin Therapy Improves Adeno-Associated Virus Transduction of Liver and Skeletal Muscle in Mice and Cultured Cells

Adeno-associated virus (AAV) gene transfer is a promising treatment for genetic abnormalities. Optimal AAV vectors are showing success in clinical trials. Gene transfer to skeletal muscle and liver is being explored as a potential therapy for some conditions, that is, α₁-antitrypsin (AAT) disorder and hemophilia B. Exploring approaches that enhance transduction of liver and skeletal muscle, using these vectors, is beneficial for gene therapy. Regulating hormones as an approach to improve AAV transduction is largely unexplored. In this study we tested whether insulin therapy improves liver and skeletal muscle gene transfer. In vitro studies demonstrated that the temporary coadministration (2, 8, and 24 hr) of insulin significantly improves AAV2-CMV-LacZ transduction of cultured liver cells and differentiated myofibers, but not of lung cells. In addition, there was a dose response related to this improved transduction. Interestingly, when insulin was not coadministered with the virus but given 24 hr afterward, there was no increase in the transgene product. Insulin receptor gene (INSR) expression levels were increased 5- to 13-fold in cultured liver cells and differentiated myofibers when compared with lung cells. Similar INSR gene expression profiles occurred in mouse tissues. Insulin therapy was performed in mice, using a subcutaneously implanted insulin pellet or a high-carbohydrate diet. Insulin treatment began just before intramuscular delivery of AAV1-CMV-schFIX or liver-directed delivery of AAV8-CMV-schFIX and continued for 28 days. Both insulin augmentation therapies improved skeletal muscle- and liver-directed gene transduction in mice as seen by a 3.0- to 4.5-fold increase in human factor IX (hFIX) levels. The improvement was observed even after the insulin therapy ended. Monitoring insulin showed that insulin levels increased during the brief period of rAAV delivery and during the entire insulin augmentation period (28 days). This study demonstrates that AAV transduction of liver or skeletal muscle can be improved by insulin therapy.