Manav Batra

Insulin Resistance and Inflammation in Hypogonadotropic Hypogonadism and Their Reduction After Testosterone Replacement in Men With Type 2 Diabetes.

OBJECTIVE One-third of men with type 2 diabetes have hypogonadotropic hypogonadism (HH). We conducted a randomized placebo-controlled trial to evaluate the effect of testosterone replacement on insulin resistance in men with type 2 diabetes and HH. RESEARCH DESIGN AND METHODS A total of 94 men with type 2 diabetes were recruited into the study; 50 men were eugonadal, while 44 men had HH. Insulin sensitivity was calculated from the glucose infusion rate (GIR) during hyperinsulinemic-euglycemic clamp. Lean body mass and fat mass were measured by DEXA and MRI. Subcutaneous fat samples were taken to assess insulin signaling genes. Men with HH were randomized to receive intramuscular testosterone (250 mg) or placebo (1 mL saline) every 2 weeks for 24 weeks. RESULTS Men with HH had higher subcutaneous and visceral fat mass than eugonadal men. GIR was 36% lower in men with HH. GIR increased by 32% after 24 weeks of testosterone therapy but did not change after placebo (P = 0.03 for comparison). There was a decrease in subcutaneous fat mass (−3.3 kg) and increase in lean mass (3.4 kg) after testosterone treatment (P < 0.01) compared with placebo. Visceral and hepatic fat did not change. The expression of insulin signaling genes (IR-β, IRS-1, AKT-2, and GLUT4) in adipose tissue was significantly lower in men with HH and was upregulated after testosterone treatment. Testosterone treatment also caused a significant fall in circulating concentrations of free fatty acids, C-reactive protein, interleukin-1β, tumor necrosis factor-α, and leptin (P < 0.05 for all). CONCLUSIONS Testosterone treatment in men with type 2 diabetes and HH increases insulin sensitivity, increases lean mass, and decreases subcutaneous fat.

Insulin infusion suppresses while glucose infusion induces Toll-like receptors and high-mobility group-B1 protein expression in mononuclear cells of type 1 diabetes patients

The purpose of this study was to determine whether an insulin infusion exerts an anti-inflammatory effect and whether the infusion of small amounts of glucose results in oxidative and inflammatory stress in patients with type 1 diabetes. Ten patients with type 1 diabetes were infused with either 2 U/h of insulin with 100 ml 5% dextrose/h to or just dextrose (100 ml/h) or physiological saline (100 ml/h) for 4 h after an overnight fast on three separate days. Blood samples were collected at 0, 2, 4, and 6 h. Insulin with glucose infusion led to the maintenance of euglycemia and a significant suppression of reactive oxygen species (ROS) generation, p47(phox) expression, Toll-like receptor (TLR)-4, TLR-2, TLR-1, CD14, high-mobility group-B1 (HMGB1), p38 mitogen-activated protein (MAP) kinase, c-Jun NH2-terminal kinase (JNK)-1, and platelet/endothelial cell adhesion molecule expression and a fall in serum concentrations of C-reactive protein, HMGB1, and rapid upon activation T cell expressed and secreted. Glucose infusion led to an increase in plasma glucose concentration from 115 (fasting) to 215 (at 4 and 6 h) mg/dl and to an increase in ROS generation, the expression of TLR-4, TLR-2, TLR-1, HMGB1, p38 MAP kinase, and JNK-1, and plasma concentrations of HMGB1. While insulin reduces indexes of oxidative and inflammatory stress in patients with type 1 diabetes, even small amounts of glucose (20 g over 4 h) induce oxidative and inflammatory stress. These effects are reflected in TLR, p38 MAP kinase, and HMGB1 expression. The induction of significant oxidative and inflammatory stress by small amounts of glucose in patients with type 1 diabetes may have important pathophysiological and therapeutic implications.

Addition of Liraglutide to Insulin in Patients With Type 1 Diabetes: A Randomized Placebo-Controlled Clinical Trial of 12 Weeks

OBJECTIVE To investigate whether addition of three different doses of liraglutide to insulin in patients with type 1 diabetes (T1D) results in significant reduction in glycemia, body weight, and insulin dose. RESEARCH DESIGN AND METHODS We randomized 72 patients (placebo = 18, liraglutide = 54) with T1D to receive placebo and 0.6, 1.2, and 1.8 mg liraglutide daily for 12 weeks. RESULTS In the 1.2-mg and 1.8-mg groups, the mean weekly reduction in average blood glucose was −0.55 ± 0.11 mmol/L (10 ± 2 mg/dL) and −0.55 ± 0.05 mmol/L (10 ± 1 mg/dL), respectively (P < 0.0001), while it remained unchanged in the 0.6-mg and placebo groups. In the 1.2-mg group, HbA1c fell significantly (−0.78 ± 15%, −8.5 ± 1.6 mmol/mol, P < 0.01), while it did not in the 1.8-mg group (−0.42 ± 0.15%, −4.6 ± 1.6 mmol/mol, P = 0.39) and 0.6-mg group (−0.26 ± 0.17%, −2.8 ± 1.9 mmol/mol, P = 0.81) vs. the placebo group (−0.3 ± 0.15%, −3.3 ± 1.6 mmol/mol). Glycemic variability was reduced by 5 ± 1% (P < 0.01) in the 1.2-mg group only. Total daily insulin dose fell significantly only in the 1.2-mg and 1.8-mg groups (P < 0.05). There was a 5 ± 1 kg weight loss in the two higher-dose groups (P < 0.05) and by 2.7 ± 0.6 kg (P < 0.01) in the 0.6-mg group vs. none in the placebo group. In the 1.2- and 1.8-mg groups, postprandial plasma glucagon concentration fell by 72 ± 12% and 47 ± 12%, respectively (P < 0.05). Liraglutide led to higher gastrointestinal adverse events (P < 0.05) and ≤1% increases (not significant) in percent time spent in hypoglycemia (<55 mg/dL, 3.05 mmol/L). CONCLUSIONS Addition of 1.2 mg and 1.8 mg liraglutide to insulin over a 12-week period in overweight and obese patients with T1D results in modest reductions of weekly mean glucose levels with significant weight loss, small insulin dose reductions, and frequent gastrointestinal side effects. These findings do not justify the use of liraglutide in all patients with T1D.

Dapagliflozin as Additional Treatment to Liraglutide and Insulin in Patients With Type 1 Diabetes

CONTEXT It is imperative that novel approaches to treatment of type 1 diabetes (T1D) are devised. OBJECTIVE The objective of the study was to investigate whether addition of dapagliflozin to insulin and liraglutide results in a significant reduction in glycemia and body weight. DESIGN This was a randomized clinical trial. SETTING The study was conducted at a single academic medical center. PARTICIPANTS Participants included T1D patients on liraglutide therapy for at least last 6 months. INTERVENTION Thirty T1D patients were randomized (in 2:1 ratio) to receive either dapagliflozin 10 mg or placebo daily for 12 weeks. MAIN OUTCOME MEASURE Change in mean glycated hemoglobin after 12 weeks of dapagliflozin when compared with placebo was measured. RESULTS In the dapagliflozin group, glycated hemoglobin fell by 0.66% ± 0.08% from 7.8% ± 0.21% (P < .01 vs placebo), whereas it did not change significantly in the placebo group from 7.40% ± 0.20% to 7.30% ± 0.20%. The body weight fell by1.9 ± 0.54kg (P < .05 vs placebo). There was no additional hypoglycemia (blood glucose < 3.88 mmol/L; P = .52 vs placebo). In the dapagliflozin group, there were significant increases in the plasma concentrations of glucagon by 35% ± 13% (P < .05), hormone-sensitive lipase by 29% ± 11% (P < .05), free fatty acids by 74% ± 32% (P < .05), acetoacetate by 67% ± 34% (P < .05), and β-hydroxybutyrate by 254% ± 81% (P < .05). Urinary ketone levels also increased significantly (P < .05). None of these changes was observed in the placebo group. Two patients in the dapagliflozin group developed diabetic ketoacidosis. CONCLUSIONS Addition of dapagliflozin to insulin and liraglutide in patients with T1D results in a significant improvement in glycemia and weight loss while increasing ketosis. If it is decided to use this approach, then it must be used only by a knowledgeable patient along with an endocrinologist who is well versed with it.

Decreased insulin secretion and incretin concentrations and increased glucagon concentrations after a high-fat meal when compared with a high-fruit and -fiber meal

This study was conducted to investigate whether a high-fat/high-carbohydrate (HFHC) meal induces an increase in plasma concentrations of glucagon, dipeptidyl peptidase-IV (DPP-IV), and CD26 expression in mononuclear cells (MNC) while reducing insulin, C-peptide, proinsulin, GIP, and GLP-1 concentrations. Ten healthy normal subjects were given either a 910-calorie HFHC meal or an American Heart Association (AHA) meal rich in fruit and fiber during the first visit and the other meal during the second visit in crossover design. Blood samples were collected at baseline and at 15, 30, 45, 60, 75, 90, 120, 180, and 300 min following the meal. There was a significantly greater increase in glucose concentrations and lower increase in postprandial insulin, C-peptide, and proinsulin concentrations and lower insulin/glucose ratios following the HFHC meal. HFHC meal intake induced marked increases in plasma glucagon and DPP-IV concentrations and an increase in CD26 mRNA expression in MNC compared with the AHA meal. In addition, the HFHC meal induced a reduction in GIP and peak GLP-1 secretion compared with the AHA meal. This was associated with a significantly greater increase in oxidative stress and proinflammatory mediators including, ROS generation, TNFα, and IL-1β mRNA expression and plasma concentrations of TBARS, FFA, and LPS. We conclude that the proinflammatory HFHC meals result in lower insulin, C-peptide, proinsulin, and GIP secretion in association with higher plasma glucagon and DPP-IV concentrations and CD26 expression in MNC compared with the AHA meal.

Anti-inflammatory and ROS Suppressive Effects of the Addition of Fiber to a High Fat High Calorie Meal

Background Fiber intake is associated with a reduction in the occurrence of cardiovascular events and diabetes. Objective To investigate whether the addition of fiber to a high-fat, high-calorie (HFHC) meal prevents proinflammatory changes induced by the HFHC meal. Design Ten normal fasting subjects consumed an HFHC meal with or without an additional 30 g of insoluble dietary fiber on 2 separate visits. Blood samples were collected over 5 hours, and mononuclear cells (MNCs) were isolated. Results Fiber addition to the HFHC meal significantly lowered glucose excursion in the first 90 minutes and increased insulin and C-peptide secretion throughout the 5-hour follow-up period compared with the meal alone. The HFHC meal induced increases in lipopolysaccharide (LPS) concentrations, MNC reactive oxygen species generation, and the expression of interleukin (IL)-1β, tumor necrosis factor α (TNF-α), Toll-like receptor (TLR)-4, and CD14. The addition of fiber prevented an increase in LPS and significantly reduced the increases in ROS generation and the expression of IL-1β, TNF-α, TLR-4, and CD14. In addition, the meal increased Suppressor of cytokine signaling (SOCS)-3 and protein tyrosine phosphatase 1B (PTP-1B) messenger RNA and protein levels, which were inhibited when fiber was added. Conclusions The addition of fiber to a proinflammatory HFHC meal had beneficial anti-inflammatory and metabolic effects. Thus, the fiber content of the American Heart Association meal may contribute to its noninflammatory nature. If these actions of dietary fiber are sustained following long-term intake, they may contribute to fibers known benefits in the prevention of insulin resistance, type 2 diabetes, and atherosclerosis.

Liraglutide acutely suppresses glucagon, lipolysis and ketogenesis in type 1 diabetes

In view of the occurrence of diabetic ketoacidosis associated with the use of sodium‐glucose transport protein‐2 inhibitors in patients with type 1 diabetes (T1DM) and the relative absence of this complication in patients treated with liraglutide in spite of reductions in insulin doses, we investigated the effect of liraglutide on ketogenesis. Twenty‐six patients with inadequately controlled T1DM were randomly divided into 2 groups of 13 patients each. After an overnight fast, patients were injected, subcutaneously, with either liraglutide 1.8 mg or with placebo. They were maintained on their basal insulin infusion and were followed up in our clinical research unit for 5 hours. The patients injected with placebo maintained their glucose and glucagon concentrations without an increase, but there was a significant increase in free fatty acids (FFA), acetoacetate and β‐hydoxybutyrate concentrations. In contrast, liraglutide significantly reduced the increase in FFA, and totally prevented the increase in acetoacetate and β‐hydroxybutyrate concentrations while suppressing glucagon and ghrelin concentrations. Thus, a single dose of liraglutide is acutely inhibitory to ketogenesis.

Oestradiol concentrations are not elevated in obesity-associated hypogonadotrophic hypogonadism

We read with interest the review on hypogonadotrophic hypogonadism (HH) associated with type 2 diabetes (T2D) and obesity by Aftab et al. The authors mention that the predominant mechanism underlying the deficient gonadotrophin secretion in this syndrome is enhanced aromatization of testosterone into oestradiol by the adipose tissue. It therefore follows that the oestradiol concentrations in men with HH and T2D/obesity should be elevated to account for the suppression of gonadotrophin secretion. However, we have shown that this widely believed presumption is not true, as also reviewed recently. Men with T2D and HH have lower oestradiol concentrations as compared to eugonadal T2D men. Oestradiol concentrations were directly related to testosterone concentrations but not to BMI. In addition, our recent data on young pubertal and postpubertal males (14–20 years of age) have shown that free testosterone concentrations are approximately 40% lower in obese adolescents as compared to lean adolescents. Similar to our study in middle-aged men with T2D, we found that oestradiol concentrations were significantly lower in adolescents with lower free testosterone as compared to those with normal testosterone. The oestradiol concentrations related directly to testosterone concentrations but not to BMI. Population-based studies such as European Male Aging Study also showed that oestradiol concentrations are lower in hypogonadal men as compared to eugonadal men, regardless of whether the hypogonadism is primary or secondary. The oestradiol concentrations in all these studies were measured by liquid or gas chromatography tandem mass spectrometry, and equilibrium dialysis was used to separate the free fraction. These assays are now considered the method of choice for measuring oestradiol, especially in subjects with low levels, such as children and adult men. In fact, no study has shown increased concentrations on oestradiol in hypogonadal men as compared to eugonadal men with obesity or T2D. The direct relationship between plasma oestradiol and testosterone concentrations is consistent with the concept that oestradiol concentrations are dependent upon testosterone, the substrate for oestradiol synthesis. Clomiphene (oestrogen antagonist) and aromatase inhibitors (which decrease oestradiol concentrations) have been shown to increase testosterone concentrations in obese men with low testosterone. This, however, cannot be taken as evidence of oestradiol as the cause of low testosterone in those men because eugonadal men also respond to aromatase inhibition by an increase in testosterone concentrations. This is because oestradiol has an inhibitory effect upon gonadotrophin secretion even in a normal physiological setting. A decrease in oestradiol action or concentration would lower its inhibitory effect upon gonadotrophins, and eugonadal men may achieve even supranormal LH, FSH and testosterone concentrations. Elevated gonadotrophin concentrations are also seen in men with congenital aromatase deficiency or absence of oestrogen receptor a. Clearly, the suppression of LH, FSH and testosterone in T2D and obesity is not induced by circulating oestradiol concentrations. The mechanism underlying this syndrome might be related to decreased insulin signalling in the hypothalamus, either by directly inhibiting GnRH release or by affecting kisspeptin production. More studies in this area are eagerly awaited.

Effect of testosterone on hepcidin, ferroportin, ferritin and iron binding capacity in patients with hypogonadotropic hypogonadism and type 2 diabetes

As the syndrome of hypogonadotropic hypogonadism (HH) is associated with anaemia and the administration of testosterone restores haematocrit to normal, we investigated the potential underlying mechanisms.

Suppressive Effect of Insulin on the Gene Expression and Plasma Concentrations of Mediators of Asthmatic Inflammation

Background and Hypothesis. Following our recent demonstration that the chronic inflammatory and insulin resistant state of obesity is associated with an increase in the expression of mediators known to contribute to the pathogenesis of asthma and that weight loss after gastric bypass surgery results in the reduction of these genes, we have now hypothesized that insulin suppresses the cellular expression and plasma concentrations of these mediators. Methods. The expression of IL-4, LIGHT, LTBR, ADAM-33, and TSLP in MNC and plasma concentrations of LIGHT, TGF-β1, MMP-9, MCP-1, TSLP, and NOM in obese patients with T2DM were measured before, during, and after the infusion of a low dose (2 U/h) infusion of insulin for 4 hours. The patients were also infused with dextrose or saline for 4 hours on two separate visits and served as controls. Results. Following insulin infusion, the mRNA expression of IL-4, ADAM-33, LIGHT, and LTBR mRNA expression fell significantly (P < 0.05 for all). There was also a concomitant reduction in plasma NOM, LIGHT, TGF-β1, MCP-1, and MMP-9 concentrations. Conclusions. Insulin suppresses the expression of these genes and mediators related to asthma and may, therefore, have a potential role in the treatment of asthma.