Glucose ingestion does not lower testosterone concentrations in men on testosterone therapy

Oral calorie intake causes an acute and transient decline in serum testosterone concentrations. It is not known whether this decline occurs in men on testosterone therapy. In this study, we evaluated the change in testosterone concentrations following oral glucose ingestion in hypogonadal men before and after treatment with testosterone therapy. This is a secondary analysis of samples previously collected from a study of hypogonadal men with type 2 diabetes who received testosterone therapy. Study participants (n = 14) ingested 75 grams of oral glucose, and blood samples were collected over 2 h. The test was repeated after 23 weeks of intramuscular testosterone therapy. The mean age and body mass index of study volunteers were 53 ± 8 years and 38 ± 7 kg/m2, respectively. Following glucose intake, testosterone concentrations fell significantly prior to testosterone therapy (week 0, p = 0.04). The nadir of testosterone concentration was at 1 h, followed by recovery to baseline by 2 h. In contrast, there was no change in testosterone concentrations at week 23. The change in serum testosterone concentrations at 60 min was significantly more at week 0 than week 23 (-11 ± 10% vs 0 ± 16%, p = 0.05). We conclude that oral glucose intake has no impact on testosterone concentrations in men on testosterone therapy. Endocrinology societies should consider clarifying in their recommendations that fasting testosterone concentrations are required for the diagnosis of hypogonadism, but not for monitoring testosterone therapy.

Glucagon-like peptide-1 receptor agonists as a possible intervention to delay the onset of type 1 diabetes: A new horizon

Type 1 diabetes (T1D) is a chronic autoimmune condition that destroys insulin-producing beta cells in the pancreas, leading to insulin deficiency and hyper-glycemia. The management of T1D primarily focuses on exogenous insulin replacement to control blood glucose levels. However, this approach does not address the underlying autoimmune process or prevent the progressive loss of beta cells. Recent research has explored the potential of glucagon-like peptide-1 receptor agonists (GLP-1RAs) as a novel intervention to modify the disease course and delay the onset of T1D. GLP-1RAs are medications initially developed for treating type 2 diabetes. They exert their effects by enhancing glucose-dependent insulin secretion, suppressing glucagon secretion, and slowing gastric emptying. Emerging evidence suggests that GLP-1RAs may also benefit the treatment of newly diagnosed patients with T1D. This article aims to highlight the potential of GLP-1RAs as an intervention to delay the onset of T1D, possibly through their potential immunomodulatory and anti-inflammatory effects and preservation of beta-cells. This article aims to explore the potential of shifting the paradigm of T1D management from reactive insulin replacement to proactive disease modification, which should open new avenues for preventing and treating T1D, improving the quality of life and long-term outcomes for individuals at risk of T1D.

Glucose response to sugar challenge moderates the effect of insulin resistance on reinforcing value of sugar-sweetened yogurt

We have shown insulin resistance is associated with the choice of sugar-sweetened over monk fruit sweetened yogurt. This study extends this research by assessing the association between insulin resistance and reinforcing value for sugar versus monk fruit-sweetened yogurt, and testing the hypothesis that this effect is moderated by greater blood glucose response in people with insulin resistance. Eighteen people with overweight/obesity (BMI = 35.8 kg/m2, range 26.2-48.5) with varying degrees of insulin resistance (Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) = 2.6, range of 0.6-8.0) had blood glucose measured for 2 h after a sugar challenge. Over six days, they consumed, in a double-blind fashion, novel flavored-colored sugar or monk fruit-sweetened yogurts, and the reinforcing value of sugar or monk fruit-sweetened yogurts and delay discounting (DD) were measured. HOMA-IR (r = 0.62, p = .006) and insulin (r = 0.51, p = .03) were related to the reinforcing value of sugar-sweetened, but not monk fruit-sweetened yogurt (r = -0.07, -0.10, respectively). The blood glucose area under the curve moderated the relationship between HOMA-IR and the reinforcing value of sugar-sweetened yogurt (p = .02). People with greater HOMA-IR and greater blood glucose excursions responded the most for sugar-sweetened yogurt. These results extend previous research and confirm the hypothesis that individual differences in response to sugar may activate brain reward centers and condition people to prefer high-sugar foods. DD was related to sugar reinforcement (r = -0.46, p = .03), consistent with the idea that those with high sugar reinforcement desire immediate gratification, and DD moderated the relationship between HOMA-IR and the reinforcing value of sugar-sweetened yogurt (p < .001). Research should test whether reducing insulin resistance would permit people with insulin resistance to choose lower-sugar foods.

Vasoactive mediators of hypertension in obesity

Obesity is associated with hypertension. However, the mechanisms involved are not fully understood. Therefore, we investigated the relationship between obesity and vasoactive mediators. In this cross-sectional study, blood pressure (BP) and vasoactive mediators of hypertension are compared among 135 adults in the nonobese, obese, and morbidly obese body mass index (BMI) ranges (BMI ≤27, 30-40, and >40 kg/m2, respectively). Angiotensinogen, angiotensin II, renin, aldosterone, endothelin-1 (ET-1), neprilysin, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), cyclic guanosine monophosphate (cGMP), and cyclic adenosine monophosphate (cAMP) levels were measured and their relationship to BP, BMI, race, and gender were investigated. Systolic and diastolic BP (SBP and DSP) were significantly higher in subjects with obesity and morbid obesity compared with nonobese. Angiotensin II, ET-1, and neprilysin were significantly higher in subjects with morbid obesity while BNP was lower. Levels of angiotensinogen, renin, aldosterone, ANP, cGMP, and cAMP did not differ between the groups. BMI was positively related to SBP, DBP, angiotensin II, ET-1, and neprilysin, and inversely related to cGMP and BNP. Age, male gender, and African-American race were associated with higher SBP. SBP was positively related to angiotensin II and ET-1 and inversely related to aldosterone, renin, and cGMP. On multivariate analyses, age, BMI, gender, and race were the main determinants of SBP, and excluding these variables, angiotensin II, aldosterone, renin, and ET-1 accounted for 21.1% ability to predict SBP. Obesity, especially morbid obesity, is associated with higher BP, higher angiotensin II and ET-1 (vasoconstrictors), and lower levels BNP and cGMP (vasodilators). SBP variability can be partly explained by angiotensin II, aldosterone, renin, and ET-1.NEW & NOTEWORTHY Our data show that obesity, especially morbid obesity, is associated with higher blood pressure levels and increases angiotensin II and endotherlin-1 (ET-1) (vasoconstrictors) and lower levels BNP and cGMP (vasodilators) and that systolic blood pressure variability can be partly explained by levels of angiotensin II, aldosterone, renin, and ET-1. The effect of these mediators on blood pressure is in addition to the effects of other known factors related to age, male gender, and AA race.

Insulin Resistance and Glycated Hemoglobin in Obesity Are Associated With Preference for Sugar-Sweetened Yogurt: A Pilot Study

OBJECTIVE

Insulin resistance is associated with elevated activation of food reward, which should be associated with an increased reinforcing value of food. Research has also shown that sugar is a macronutrient strongly associated with reward and reinforcing value of food. This research is designed to assess whether insulin resistance is associated with a stronger preference for sugar-sweetened, thus elevating blood glucose responses in obese people with varying degrees of insulin resistance.

METHODS

Thirteen people with obesity (body mass index, 39.1 kg/m 2 ; range, 30.0-45.1 kg/m 2 ) with varying degrees of insulin resistance (Homeostatic Model Assessment of Insulin Resistance, 5.2; range, 0.7-11.6) consumed novel flavored-colored yogurts that were sweetened with either sugar or monkfruit daily for 6 days to assess whether when given the choice of sugar-sweetened versus monkfruit-sweetened yogurts to consume, participants preferred sugar-sweetened yogurts.

RESULTS

Participants consumed a greater amount ( p = .009) and percentage ( p = .04) of sugar-sweetened yogurt earned than monkfruit-sweetened yogurt. The percent of sugar-sweetened versus monkfruit-sweetened yogurt consumed in relationship to amount earned was related to insulin resistance ( r = 0.64, p = .019), glycated hemoglobin ( r = 0.61, p = .027), insulin ( r = 0.58, p = .007), and glucose ( r = 0.56, p = .048).

CONCLUSIONS

Insulin resistance is associated with preference for sugar-sweetened foods in participants with obesity, which may make it hard to make dietary changes. Research is needed to assess whether treatments that improve insulin resistance also change the preference for sugar-sweetened or high-glycemic-index foods.

LBSUN213 An Investigation Into The Effects Of Dapagliflozin On Ketogenesis In Type 1 Diabetes

Background

Treatment with sodium-glucose transporter (SGLT)-2 inhibitors in patients with type 1 diabetes (T1DM) is associated with increased ketogenesis and diabetic ketoacidosis (DKA). The exact relationship between SGLT-2 inhibitors use in T1DM and ketogenesis is not fully understood.

Patients and Methods

In this single center, randomized, double blind and placebo-controlled trial 70 patients with established T1DM were randomized into placebo, dapagliflozin (SGLT-2 inhibitor) alone, exenatide/Bydureon (short and long-term acting GLP-1 RA, respectively) alone or with dapagliflozin and exenatide/Bydureon (triple therapy) groups in addition to routine insulin treatment (titrated in all groups to reduce risk of hypoglycemia). Patients were tested acutely (single dose before and after 12 weeks of treatment) under extended fasting and insulinopenic conditions (stress conditions) and under basal fasting conditions during 12 weeks treatment period.

Results

At end of 12 weeks treatment, glycemic indices improved significantly compared to baseline in the dapagliflozin and Bydureon alone groups and improved significantly compared to placebo in the triple therapy group (HbA1c: -0.9±0.1%, p&lt;0. 001). Weight loss was significant (p&lt;0. 001) in all active treatment groups. Ketones (beta-hydroxybutyrate, BHB) increased significantly in blood (0.21±0. 04 to 1.57±0.21 mM) and urine under acute stress conditions in control group at baseline and at 12 weeks visits. The magnitude of this increase was reduced following a single dose of dapagliflozin or exenatide at baseline visit (average of 1.16±0.17 mM) but was further increased following a single dose in the dapagliflozin receiving groups at 12 weeks visit (average of 1.83±0.28 mM). Under acute testing conditions, single dose of dapagliflozin treatment was associated with reduced urinary BHB clearance at baseline and 12 weeks visits. After 12 weeks of treatment and under basal conditions, ketone levels in blood and urine were not significantly altered following dapagliflozin or Bydureon alone but were significantly higher in the triple therapy group (0.22±0. 04 to 0.42±0. 07 mM in blood). At 12 weeks of treatment, dapagliflozin was associated with increased glucagon and lipolysis (increased FFAs) while Bydureon was associated with decreased glucagon and lipolysis. During the 12 weeks there were no episode of DKA or hypoglycemia (&lt;55mg/dl).

Conclusions

Adjunct therapies treatment in T1DM results in significant improvements in glycemia and HbA1c. Dapagliflozin treatment increases lipolysis and glucagon while reduces urinary excretion of BHB. This may contribute to the increased blood ketone levels following extended treatment with dapagliflozin. However, the magnitude of this increase in ketones is significantly below DKA ketones levels which indicates that other DKA triggering factors play a more significant role.

Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Improving the residual risk of renal and cardiovascular outcomes in diabetic kidney disease: A review of pathophysiology, mechanisms, and evidence from recent trials

Based on global estimates, almost 10% of adults have diabetes, of whom 40% are estimated to also have chronic kidney disease (CKD). Almost 2 decades ago, treatments targeting the renin-angiotensin system (RAS) were shown to slow the progression of kidney disease. More recently, studies have reported the additive benefits of antihyperglycaemic sodium-glucose co-transporter-2 inhibitors in combination with RAS inhibitors on both CKD progression and cardiovascular outcomes. However, these recent data also showed that patients continue to progress to kidney failure or die from kidney- or cardiovascular-related causes. Therefore, new agents are needed to address this continuing risk. Overactivation of the mineralocorticoid (MR) receptor contributes to kidney inflammation and fibrosis, suggesting that it is an appropriate treatment target in patients with diabetes and CKD. Novel, selective non-steroidal MR antagonists are being studied in these patients, and the results of two large recently completed clinical trials have shown that one such treatment, finerenone, significantly reduces CKD progression and cardiovascular events compared with standard of care. This review summarizes the pathogenic mechanisms of CKD in type 2 diabetes and examines the potential benefit of novel disease-modifying agents that target inflammatory and fibrotic factors in these patients.

High prevalence of subnormal testosterone in obese adolescent males: reversal with bariatric surgery

OBJECTIVE

Obesity in adolescent males is associated with the lowering of total and free testosterone concentrations. Weight loss may increase testosterone concentrations.

DESIGN AND METHODS

We evaluated the changes in sex hormones following bariatric surgery in 34 males (age range: 14.6-19.8 years) with obesity. These participants were part of a prospective multicenter study, Teen-Longitudinal Assessment of Bariatric Surgery. The participants were followed up for 5 years after surgery. Total testosterone, total estradiol, luteinizing hormone, follicle-stimulating hormone, sex hormone-binding globulin, C-reactive protein, insulin and glucose were measured at baseline, 6 months and annually thereafter. Free testosterone, free estradiol and HOMA2-IR were calculated.

RESULTS

Study participants lost one-third of their body weight after bariatric surgery, with maximum weight loss achieved at 24 months for most participants. Free testosterone increased from 0.17 (95% CI: 0.13 to 0.20) at baseline to 0.34 (95% CI: 0.30 to 0.38) and 0.27 nmol/L (95% CI: 0.23 to 0.32) at 2 and 5 years (P < 0.001 for both), respectively. Total testosterone increased from 6.7 (95% CI: 4.7 to 8.8) at baseline to 17.6 (95% CI: 15.3 to 19.9) and 13.8 (95% CI: 11.0 to 16.5) nmol/L at 2 and 5 years (P < 0.001), respectively. Prior to surgery, 73% of the participants had subnormal free testosterone (<0.23 nmol/L). After 2 and 5 years, only 20 and 33%, respectively, had subnormal free testosterone concentrations. Weight regain was related to a fall in free testosterone concentrations.

CONCLUSIONS

Bariatric surgery led to a robust increase in testosterone concentrations in adolescent males with severe obesity. Participants who regained weight had a decline in their testosterone concentrations.

4-Phenylbutyric acid improves free fatty acid-induced hepatic insulin resistance in vivo

Plasma free fatty acids (FFAs) are elevated in obesity and can induce insulin resistance via endoplasmic reticulum (ER) stress. However, it is unknown whether hepatic insulin resistance caused by the elevation of plasma FFAs is alleviated by chemical chaperones. Rats received one of the following i.v. treatments for 48 h: saline, intralipid plus heparin (IH), IH plus the chemical chaperone 4-phenylbutyric acid (PBA), or PBA alone and a hyperinsulinemic-euglycemic clamp was performed during the last 2 h. PBA co-infusion normalized IH-induced peripheral insulin resistance, similar to our previous findings with an antioxidant and an IκBα kinase β (IKKβ) inhibitor. Different from our previous results with the antioxidant and IKKβ inhibitor, PBA also improved IH-induced hepatic insulin resistance in parallel with activation of Akt. Unexpectedly, IH did not induce markers of ER stress in the liver, but PBA prevented IH-induced elevation of phosphorylated eukaryotic initiation factor-2α protein in adipose tissue. PBA tended to decrease circulating fetuin-A and significantly increased circulating fibroblast growth factor 21 (FGF21) without affecting markers of activation of hepatic protein kinase C-δ or p38 mitogen-activated protein kinase that we have previously involved in hepatic insulin resistance in this model. In conclusion: (i) PBA prevented hepatic insulin resistance caused by prolonged plasma FFA elevation without affecting hepatic ER stress markers; (ii) the PBA effect is likely due to increased FGF21 and/or decreased fetuin-A, which directly signal to upregulate Akt activation.

Dapagliflozin reduces systolic blood pressure and modulates vasoactive factors

AIM

To investigate the mechanisms underlying improvements in blood pressure (BP) and congestive heart failure outcomes following treatment with dapagliflozin, a sodium-glucose co-transporter-2 inhibitor.

RESEARCH DESIGN AND METHODS

A total of 52 patients with type 2 diabetes (T2D) with an HbA1c of less than 8% participated in this prospective, double-blind and placebo-controlled study. Patients were randomized (1:1) to either dapagliflozin 10 mg daily or placebo for 12 weeks. Half the patients were also monitored for 6 h following their first dose for acute effects on BP. Blood and urine samples were collected and levels of angiotensinogen, angiotensin II, renin, aldosterone, endothelin-1, atrial natriuretic peptide (ANP), brain natriuretic peptide, cyclic adenosine monophosphate, cyclic guanosine monophosphate (cGMP) and neprilysin were measured. The expression of angiotensin-converting enzyme, guanylate cyclase and phosphodiesterase 5 (PDE5) was measured in circulating mononuclear cells (MNC).

RESULTS

A total of 24 and 23 patients receiving dapagliflozin and placebo, respectively, completed the 12-week study. Systolic BP decreased significantly, compared with placebo, both after single-dose (by 7 ± 3 mmHg) and 12-week (by 7 ± 2 mmHg) treatment with dapagliflozin. Dapagliflozin suppressed angiotensin II and angiotensinogen (by 10.5 ± 2.1 and 1.45 ± 0.42 μg/mL, respectively) and increased ANP and cGMP (by 34 ± 11 and 29 ± 11 pmol/mL, respectively) compared with the placebo group. cGMP levels also increased acutely following a single dose of dapagliflozin. Dapagliflozin also suppressed PDE5 expression by 26% ± 11% in MNC. There were no changes observed in the other vasoactive mediators investigated.

CONCLUSIONS

Dapagliflozin administration in T2D resulted in both acute and chronic reduction in systolic BP, a reduction in vasoconstrictors and an increase in vasodilators. These changes may potentially contribute to its antihypertensive effects and its benefits in congestive cardiac failure.

Mechanisms underlying the metabolic actions of testosterone in humans: A narrative review

The role of testosterone in improving sexual symptoms in men with hypogonadism is well known. However, recent studies indicate that testosterone plays an important role in several metabolic functions in males. Multiple PubMed searches were conducted with the use of the terms testosterone, insulin sensitivity, obesity, type 2 diabetes, anaemia, bone density, osteoporosis, fat mass, lean mass and body composition. This narrative review is focused on detailing the mechanisms that underlie the metabolic aspects of testosterone therapy in humans. Testosterone enhances insulin sensitivity in obese men with hypogonadism by decreasing fat mass, increasing lean mass, decreasing free fatty acids and suppressing inflammation. At a cellular level, testosterone increases the expression of insulin receptor β subunit, insulin receptor substrate-1, protein kinase B and glucose transporter type 4 in adipose tissue and adenosine 5'-monophosphate-activated protein kinase expression and activity in skeletal muscle. Observational studies show that long-term therapy with testosterone prevents progression from prediabetes to diabetes and improves HbA1c. Testosterone increases skeletal muscle satellite cell activator, fibroblast growth factor-2 and decreases expression of the muscle growth suppressors, myostatin and myogenic regulatory factor 4. Testosterone increases haematocrit by suppressing hepcidin and increasing expression of ferroportin along with that of transferrin receptor and plasma transferrin concentrations. Testosterone also increases serum osteocalcin concentrations, which may account for its anabolic actions on bone. In conclusion, testosterone exerts a series of potent metabolic effects, which include insulin sensitization, maintenance and growth of the skeletal muscle, suppression of adipose tissue growth and maintenance of erythropoiesis and haematocrit.

Liraglutide treatment in overweight and obese patients with type 1 diabetes: A 26-week randomized controlled trial; mechanisms of weight loss

AIM

To investigate the effects of liraglutide treatment on glycaemic control and adipose tissue metabolism in overweight and obese people with type 1 diabetes (T1DM).

RESEARCH DESIGN AND METHODS

A total of 84 adult overweight and obese patients with T1DM, with no detectable C-peptide, were randomized (1:1) to either placebo or 1.8 mg/d liraglutide for 6 months. Blood samples were collected at 0, 12 and 26 weeks. Subcutaneous adipose tissue biopsies, a high-calorie high-fat meal challenge test, continuous glucose monitoring, dual-energy X-ray absorptiometry and MRI were performed before and at the end of treatment.

RESULTS

In all, 37 and 27 patients who received liraglutide and placebo, respectively, completed the study. Glycated haemoglobin fell by 0.41 ± 0.18% (4.5±1.4 mmol/mol) from baseline after liraglutide treatment (P = 0.001), and by 0.29 ± 0.19% (3.1±2.0 mmol/mol) compared to placebo (P = 0.1). There was no increase in hypoglycaemia, while the time spent in normal glycaemia increased (P = 0.015) and time spent in hyperglycaemia decreased (P = 0.019). Body weight fell significantly in the liraglutide group, mostly in the form of fat mass loss (including visceral fat), with no change in lean mass. Systolic blood pressure (SBP) also fell after liraglutide treatment. Liraglutide also caused a significant increase in the expression of adipose tissue triglyceride lipase, carnitine palmitoyl transferase-1, peroxisome proliferator-activated receptor (PPAR)α, PPARδ, uncoupling protein-2 and type 2 iodothyronine deiodinase in the adipose tissue.

CONCLUSIONS

Liraglutide improves glycaemia, reduces adiposity and SBP. Liraglutide also stimulates mechanisms involved with an increase in lipid oxidation and thermogenesis, while conserving lean body mass.

Type 1 diabetes and hearing loss: Audiometric assessment and measurement of circulating levels of soluble receptor for advanced glycation end products

BACKGROUND

We examined the hearing function in adults with and without type 1 diabetes (T1D) to investigate whether an association exists between hearing loss and duration of diabetes, haemoglobin A1C level, diabetes complications and levels of select serum and urinary biomarkers.

METHODS

We measured pure tone audiometry (PTA) thresholds; serum levels of C-reactive protein (CRP), vascular endothelial growth factor (VEGF), soluble receptors for advanced glycation end-product (sRAGE); and urinary isoprostane in 30 adults with T1D (age 43.8 ± 11.4 years). We also measured PTA thresholds in 11 adults without diabetes (age 53 ± 5.5 years).

RESULTS

63.3% of adults with T1D had high-frequency hearing loss. Among adults with T1D, those with hearing loss were older (48.2 vs 36.2 years old, P < .01), had a longer duration of diabetes (30.7 vs 21.2 years, P = .02), a greater prevalence of peripheral neuropathy (57.9 vs 9.1%, P = .02) and significantly lower median levels of sRAGE (1054.27 vs 1306.83 pg/mL, P = .03) compared to those with normal hearing. Adults with T1D between the ages of 40 and 60 years old, who had diabetes for ≥35 years, had significantly higher PTA thresholds at both 500and 8000 Hz than age-matched adults without diabetes.

CONCLUSIONS

A significant proportion of adults with T1D have high-frequency hearing loss before age of 60 that is positively associated with age, duration of diabetes and presence of peripheral neuropathy. Our results are in support of previous studies suggesting a potential protective role of sRAGE against AGE toxicity and diabetes complications.

Bariatric Surgery: Remission of Inflammation, Cardiometabolic Benefits, and Common Adverse Effects

Obesity is associated with increased mortality as a result of several comorbidities which occur in tandem with the obese state. Chronic inflammation is well documented in obesity, and evidence from numerous studies support the notion that the increased inflammation in individuals with obesity accentuates the comorbidities seen in this condition. The remission of comorbidities such as metabolic, cardiovascular, and neurological complications occurs following bariatric procedures. Bariatric surgery significantly reduces mortality and results in remarkable weight loss and reversal in several obesity-related comorbidities. There is indisputable evidence that the resolution of inflammation that occurs after bariatric surgery mitigates some of these comorbidities. With the increasing use of bariatric surgery for the treatment of severe obesity, it is pivotal to elucidate the underlying mechanisms responsible for the notable improvements seen after the procedure. This review summarizes underlying mechanisms responsible for the remission of obesity-related abnormalities and discusses the common adverse effects of bariatric surgery. Well-stratified, large-scale studies are still needed for a proper evaluation of these underlying mechanisms.

SUN-560 Simvastatin Inhibits the Pro-Inflammatory and Pro-Atherogenic Effects of Cream in Obese Subjects

Our previous work has shown that the ingestion of cream induces an increase in oxidative stress and other cellular and molecular indices of inflammation and atherosclerosis and that treatment with Vytorin for 6 weeks reduced and reversed majority of the effects of cream. However, it is not clear which component of Vytorin, simvastatin or ezetimibe, is responsible for these intriguing and potent effects. Therefore, we further investigated the effects of simvastatin treatment on indices of inflammation and atherosclerosis at baseline and following intake of dairy cream. Ten obese patients with LDL >100mg/dl were given simvastatin 40mg/day for 6 weeks. Subjects were asked to ingest 33ml of cream (about 300 Calories) containing about 85% saturated fat. Fasting and post-cream intake blood samples were obtained at baseline and at 6 weeks. Total cholesterol and LDLc concentrations were lowered significantly at 6 weeks following simvastatin (p<0.05). Cream intake at 0 week induced significant increases in MNC expression of IL-1β (by 58±16%), TNF-α (by 79±19%), CD16 (by 103±32%), MMP-9 (by 68±17%), TLR-4 (by 68±12%) and TLR-2 (by 53±9%) over the baselines (p<0.05 for all). Cream intake at 0 week also induced a significant increase in IL-1β plasma concentrations by 94±18% over the baseline. Simvastatin treatment suppressed fasting levels of CD68 expression in MNC (by 38±9, p<0.05) and fasting plasma levels of IL-18 and MMP-9 (by 24±11% and 28±12%, respectively, p>0.05) compared to fasting levels at 0 week. The increase in IL-1β, TNFα, CD16 and MMP-9 expression in MNC following cream intake at end of simvastatin treatment was significantly suppressed (by 41±15%, 48±17%, 87±16% and 34±8%, respectively, p<0.05) compared to that before simvastatin treatment. In addition, there was a paradoxical suppression of the expression of TLR-2 and TLR-4 (by 30±11% and 24±9%, respectively) below baseline levels following cream at 6 weeks. Simvastatin treatment also suppressed cream induced increases in plasma IL-1β concentrations by 37±11% (p<0.05, compared to increases at 0 week). We conclude that simvastatin exerts a powerful anti-inflammatory effect and reduces expression of pro-inflammatory mediators induced by cream intake. This effect is similar in nature to that observed previously with Vytorin with some differences in the magnitude of the changes.

Dapagliflozin Suppresses Hepcidin And Increases Erythropoiesis

CONTEXT

Dapagliflozin and other SGLT2 inhibitors are known to increase hematocrit, possibly due to its diuretic effects and hemoconcentration.

OBJECTIVE

Since type 2 diabetes is a proinflammatory state and since hepcidin, a known suppressor of erythropoiesis, is increased in proinflammatory states, we investigated the possibility that dapagliflozin suppresses hepcidin concentrations and thus increases erythropoiesis.

DESIGN

Prospective, randomized, and placebo-controlled study.

SETTING

Single endocrinology center.

PATIENTS

Fifty-two obese type 2 diabetes patients.

INTERVENTION

Patients were randomized (1:1) to either dapagliflozin (10 mg daily) or placebo for 12 weeks. Blood samples were collected before and after treatments and serum, plasma, and mononuclear cells (MNC) were prepared.

MAIN OUTCOME MEASURE

Hepcidin and other hematopoietic factors.

RESULTS

Following dapagliflozin treatment, there was a significant fall in HbA1c and a significant increase in hemoglobin concentration and hematocrit. Dapagliflozin treatment significantly reduced circulating hepcidin and ferritin concentrations while causing a significant increase in levels of the hepcidin inhibitor, erythroferrone, and a transient increase in erythropoietin. Additionally, dapagliflozin increased plasma transferrin levels and expression of transferrin receptors 1 and 2 in MNC, while there was no change in the expression of the iron cellular transporter, ferroportin. Dapagliflozin treatment also caused a decrease in hypoxia-induced factor-1α expression in MNC while it increased the expression of its inhibitor, prolyl hydroxylase-2. There were no significant changes in any of these indices in the placebo group.

CONCLUSIONS

We conclude that dapagliflozin increases erythropoiesis and hematocrit through mechanisms that involve the suppression of hepcidin and the modulation of other iron regulatory proteins.

Testosterone Increases the Expression and Phosphorylation of AMP Kinase α in Men With Hypogonadism and Type 2 Diabetes

CONTEXT

Adenosine 5'-monophosphate-activated protein kinase-α (AMPKα) is a mediator of exercise-induced glucose uptake in skeletal muscle.

OBJECTIVE

We evaluated whether AMPKα expression and phosphorylation are reduced in skeletal muscle and adipose tissue of patients with hypogonadotropic hypogonadism (HH), and whether testosterone replacement therapy results in restoration of the expression and phosphorylation of AMPKα.

DESIGN

This is a secondary analysis of a previously completed trial that showed an insulin-sensitizing effect of testosterone therapy in men with type 2 diabetes and HH.

SETTING

Clinical research center at university.

PATIENTS

Thirty-two men with HH and 32 eugonadal men were compared at baseline.

INTERVENTIONS

Men with HH were treated with intramuscular injections of testosterone or placebo every 2 weeks for 22 weeks. Quadriceps muscle biopsies and subcutaneous abdominal fat biopsies were obtained before and after 4-hour euglycemic hyperinsulinemic clamp, prior to and after testosterone or placebo therapy.

OUTCOME MEASURES AND RESULTS

mRNA expression of AMPKα in hypogonadal men was lower by 37% in adipose tissue and 29% in skeletal muscle, respectively, compared with levels in eugonadal men, while phosphorylated AMPKα was lower by 22% and 28%, respectively. Following testosterone replacement, the expression of AMPKα did not alter in the fasting state but increased markedly by 41% and 46% in adipose tissue and muscle, respectively, after the clamp. In contrast, phosphorylated AMPKα increased by 69% in muscle after testosterone therapy but did not change following the clamp.

CONCLUSIONS

Testosterone modulates the expression of AMPKα and phosphorylated AMPKα. These effects may contribute to the improved insulin sensitivity following testosterone therapy.

Acute effects of insulin on skeletal muscle growth and differentiation genes in men with type 2 diabetes

AIMS

Insulin has anabolic effects on skeletal muscle. However, there is limited understanding of the molecular mechanisms underlying this effect in humans. We evaluated whether the skeletal muscle expression of satellite cell activator fibroblast growth factor 2 (FGF2) and muscle growth and differentiation factors are modulated acutely by insulin during euglycemic-hyperinsulinemic clamp (EHC).

DESIGN AND METHODS

This is a secondary investigation and analysis of samples obtained from a previously completed trial investigating the effect of testosterone replacement in males with hypogonadotropic hypogonadism and type 2 diabetes. Twenty men with type 2 diabetes underwent quadriceps muscle biopsies before and after 4 h of EHC.

RESULTS

The infusion of insulin during EHC raised the expression of myogenic growth factors, myogenin (by 72 ± 20%) and myogenin differentiation protein (MyoD; by 81 ± 22%). Insulin reduced the expression of muscle hypertrophy suppressor, myogenic regulatory factor 4 (MRF4) by 34 ± 14%. In addition, there was an increase in expression of FGF receptor 2, but not FGF2, following EHC. The expression of myostatin did not change.

CONCLUSIONS

Insulin has an acute potent effect on expression of genes that can stimulate muscle differentiation and growth.

Macronutrient-Mediated Inflammation and Oxidative Stress: Relevance to Insulin Resistance, Obesity, and Atherogenesis

CONTEXT

The intake of macronutrients as components of a Western dietary pattern leads to oxidative stress and inflammation.

EVIDENCE ACQUISITION

Data were largely retrieved from our previous and most recent work. PubMed and Google Scholar were searched for recent articles on the effect of macronutrients/dietary intake on inflammation, insulin resistance, obesity, and atherogenesis. The most relevant, high-quality articles were included in our review.

EVIDENCE SYNTHESIS

Our previous work has demonstrated the molecular mechanisms of macronutrient-mediated oxidative stress and inflammation. With the induction of inflammation, proinflammatory molecules potentially interfere with insulin signal transduction, thus causing insulin resistance. In addition, other molecules promote atherogenic inflammation. More recently, our work has also shown that certain foods are noninflammatory or anti-inflammatory and thus, do not interfere with insulin signaling. Finally, as obesity is induced by chronic excessive caloric intake, it is characterized by an increase in the expression of proinflammatory molecules, which are induced acutely by a Western diet. Caloric restriction, including fasting, is associated with a reduction in oxidative and inflammatory stress.

CONCLUSIONS

This review summarizes and attempts to provide an up-to-date profile of the molecular mechanisms involved in macronutrient-mediated oxidative/inflammatory stress and its potential consequences. An understanding of these underlying mechanisms is crucial for making appropriate dietary choices.

Increase in Osteocalcin Following Testosterone Therapy in Men With Type 2 Diabetes and Subnormal Free Testosterone

Context

One-third of men with type 2 diabetes have subnormal free testosterone concentrations. We evaluated the following: (i) whether bone mineral density (BMD) and bone strength are affected by gonadal status in type 2 diabetes and (ii) the effect of testosterone replacement on markers of osteoblast and osteoclast activity.

Design

This is a secondary analysis of a previously completed, randomized, placebo-controlled trial. Ninety-four men with type 2 diabetes were recruited; 44 had subnormal free testosterone concentrations. Men with subnormal free testosterone concentrations were randomized to receive intramuscular injections of testosterone or placebo every 2 weeks for 22 weeks. Dual energy X-ray absorptiometry scans were performed at baseline and at 23 weeks.

Results

Men with subnormal free testosterone had similar BMD compared with men with normal free testosterone. However, bone strength indices were lower in men with subnormal free testosterone. BMD was related to free estradiol concentrations (r = 0.37, P = 0.004 at hip), whereas bone strength was related to free testosterone concentrations (r = 0.41, P < 0.001). Testosterone replacement increased osteocalcin concentrations [mean change (95% CI), 3.52 (0.45, 6.59), P = 0.008]. C-Terminal telopeptide (CTx) concentrations also increased at 15 weeks but reverted to baseline following that. There were no changes in other bone turnover markers or BMD.

Conclusion

We conclude that testosterone replacement resulted in an increase in osteocalcin and a transient increase in CTx, indicating an increase in osteoblastic activity and transient increase in bone breakdown. Therefore, a major action of testosterone is to increase bone turnover in men with type 2 diabetes.

Effect of Testosterone on FGF2, MRF4, and Myostatin in Hypogonadotropic Hypogonadism: Relevance to Muscle Growth

CONTEXT

Fibroblast growth factor (FGF)2 is an important stimulatory modulator of satellite cells in skeletal muscle. Satellite cells play a cardinal role in muscle growth and repair.

OBJECTIVE

We evaluated whether skeletal muscle expression of FGF2 and muscle growth and differentiation factors are reduced in patients with hypogonadotropic hypogonadism (HH) and whether testosterone replacement therapy results in their restoration.

DESIGN

This is a secondary analysis of a previously completed trial of testosterone replacement in men with type 2 diabetes and HH.

SETTING

Clinical Research Center at a university.

PATIENTS

Twenty-two men with HH and 20 eugonadal men were compared at baseline.

INTERVENTIONS

Twelve men with HH were treated with intramuscular injections of 250 mg testosterone every 2 weeks for 22 weeks, and 10 men received placebo injections. Quadriceps muscle biopsies and blood samples were obtained before and after testosterone therapy.

OUTCOME MEASURES AND RESULTS

The expression of FGF2 and FGF receptor (FGFR)2 in skeletal muscle of men with HH was significantly lower than that in eugonadal men by 57% and 39%, respectively (P < 0.05). After 22 weeks of testosterone, the expression of FGF2 increased, whereas that of myogenic regulatory factor (MRF)4 and myostatin decreased significantly. There was no change in expression of FGFR2, myogenin, or myogenic differentiation protein in the skeletal muscle. Plasma FGF2 and IGF-1 concentrations increased after testosterone therapy.

CONCLUSIONS

These data show that testosterone is a major modulator of FGF2, MRF4, and myostatin expression in skeletal muscle. These effects may contribute to the increase in muscle mass after testosterone therapy.

OR14-2 Liraglutide Treatment in Overweight and Obese Patients with Type 1 Diabetes: A 26 weeks Randomized Controlled Trial

We have previously demonstrated that a 12-week addition of liraglutide to insulin therapy in patients with type 1 diabetes (T1D) results in an improvement in glycemic control, weight loss and a reduction in systolic blood pressure (SBP). We have now conducted a 6 month randomized study investigating effects of liraglutide in overweight and obese patients with T1DM. All patients had T1D for at least one year, were on insulin therapy and had no detectable c-peptide in plasma (mean BMI: 31.2±1.1kg/m², mean HbA1c: 7.85±0.19%, mean age: 46.1±1.7 years, mean age of T1D diagnosis: 18.5±2.2 years). Twenty seven and 37 patients (out of total of 85 randomized patients) who received placebo or 1.8mg Liraglutide, respectively, for 26 weeks completed the study. Continuous glucose monitoring (CGM) was performed for 2 weeks before and at end of treatment. At the end of 26 weeks treatment with liraglutide, HbA1c fell significantly by 0.41±0.18% (p=0.001 vs baseline) from 7.96±0.19 to 7.55±0.18%. Placebo adjusted fall in HbA1c was 0.34±0.14 (p= 0.037) at 12 weeks and 0.29±0.19% (p=0.1) at 26 weeks. Placebo adjusted weekly average blood glucose fell by 14±5mg/dl (p=0.069 vs placebo) from 182±7 to 166±6mg/dl (p=0.021 vs baseline) and fasting weekly glucose fell by 11±9mg/dl (p=0.086 vs placebo) from 175±8 to 159±11mg/dl (p=0.032 vs baseline). There was no significant change in percent time spent in hypoglycemic range while the percent time spent in normal range (70-160mg/dl) increased significantly by 7±2% (from 44±3% to 51±2%, p=0.015) and time spent in hyperglycemic range (>160mg/dl) decreased by 8±3% (from 52±4 to 44±4%, p=0.019). There was also a concurrent fall in total and bolus insulin doses. Weight fell by 4.6±0.8kg (placebo adjusted, p=0.001) in the liraglutide group mostly in the form of fat mass loss (3.2±0.6kg, p=0.01 vs placebo) with no change in lean mass as measured by DEXA. Placebo corrected SBP also fell following liraglutide treatment by 5±3mmHg (p=0.076) from 125±3 to 120±3mmHg (p=0.023 vs baseline) with no change in diastolic BP. We conclude that the addition of liraglutide to insulin treatment in obese and overweight patients with type 1 diabetes improves indices of glycemia, body weight and blood pressure without additional risk of hypoglycemia.

Addition of glucagon-like peptide-1 receptor agonist therapy to insulin in C-peptide-positive patients with type 1 diabetes

We aimed to test the hypothesis that addition of glucagon-like peptide-1 receptor agonists (GLP-1RAs) to insulin in C-peptide-positive patients with type 1 diabetes (T1D) will result in a reduction in glycated haemoglobin (HbA1c) with reduced insulin requirements and a rise in C-peptide concentrations. We conducted a retrospective analysis of 11 normal-weight patients with T1D consecutively treated with a GLP-1RA in addition to insulin. Paired t tests were used to compare the changes in HbA1c, insulin doses, body weight, body mass index, and C-peptide concentrations prior to and 12 ± 1 weeks after GLP-1RA therapy. At the end of 12 ± 1 weeks of GLP-1RA therapy, HbA1c fell from 10.74 ± 0.96% (95 ± 10.5 mmol/mol) to 7.4 ± 0.58% (58 ± 6.3mmol/mol) (P < 0.01), body weight fell from 71 ± 2.0 to 69 ± 2 kg (P = 0.06), and total insulin dose was reduced by 64% from 33 ± 6 to 11 ± 5 units (P < 0.01). Five out of 10 patients did not require any insulin. C-peptide concentrations increased significantly from 0.43 ± 0.09 ng/ml (0.14 ± 0.02 nmol/L) to 1.42 ± 0.42ng/ml (0.47 ± 0.13 nmol/L) (P = 0.01). Addition of GLP-1RA therapy to insulin in normal-weight patients with T1D led to a reduction in HbA1c with reduced insulin requirements, a 3.5-fold increase in C-peptide concentrations and freedom from insulin therapy in 50% of patients who tolerated the GLP-1RA therapy over a period of 12 ± 1 weeks.

Decreases in neprilysin and vasoconstrictors and increases in vasodilators following bariatric surgery

The aim of this study was to determine if weight loss following Roux-en-Y gastric bypass (RYGB) surgery in morbidly obese patients is associated with a decrease in plasma concentrations of neprilysin, mediators of the renin angiotensin system (RAS), catecholamines and endothelin-1, and also with an increase in the concentrations of vasodilators. Fasting blood samples were obtained from 15 patients with morbid obesity and diabetes prior to and 6 months after RYGB surgery. Circulating levels of neprilysin, vasoconstrictors, vasodilators, and the mRNA expression of related genes in circulating mononuclear cells (MNC) were measured. Six months after RYGB surgery the concentrations of neprilysin, angiotensinogen, angiotensin II, renin and endothelin-1 fell significantly by 27 ±16%, 22 ±10%, 22 ±8%, 35 ±13% and 17 ±6% (P < .05 for all), respectively, while ANP concentrations increased significantly by 24 ±13%. There was no significant change in aldosterone, BNP, cAMP or cGMP concentrations, or angiotensin converting enzyme (ACE) expression. These changes may contribute to the reduction of congestive cardiac failure and blood pressure risks after RYGB surgery.

Hypogonadotropic Hypogonadism in Men With Diabesity

One-third of men with obesity or type 2 diabetes have subnormal free testosterone concentrations. The lower free testosterone concentrations are observed in obese men at all ages, including adolescents at completion of puberty. The gonadotropin concentrations in these males are inappropriately normal; thus, these patients have hypogonadotropic hypogonadism (HH). The causative mechanism of diabesity-induced HH is yet to be defined but is likely multifactorial. Decreased insulin and leptin signaling in the central nervous system are probably significant contributors. Contrary to popular belief, estrogen concentrations are lower in men with HH. Men with diabesity and HH have more fat mass and are more insulin resistant than eugonadal men. In addition, they have a high prevalence of anemia and higher mortality rates than eugonadal men. Testosterone replacement therapy results in a loss of fat mass, gain in lean mass, and increase in insulin sensitivity in men with diabesity and HH. This is accompanied by an increase in insulin-signaling genes in adipose tissue and a reduction in inflammatory mediators that interfere with insulin signaling. There is also an improvement in sexual symptoms, anemia, LDL cholesterol, and lipoprotein (a). However, testosterone therapy does not consistently affect HbA_1c in men with diabetes. The effect of testosterone replacement on cardiovascular events or mortality in men with diabesity is not known and remains to be studied in prospective trials.

Exenatide Increases IL-1RA Concentration and Induces Nrf-2‒Keap-1‒Regulated Antioxidant Enzymes: Relevance to β-Cell Function

PURPOSE

We previously demonstrated the anti-inflammatory and antioxidant effects of exenatide. We now hypothesized that exenatide also increases the plasma concentration of interleukin-1 receptor antagonist (IL-1RA), an endogenous anti-inflammatory protein, and modulates the nuclear factor erythroid 2‒related factor‒Kelchlike ECH-associated protein 1‒antioxidant response element (Nrf-2‒Keap-1‒ARE) system to induce key antioxidant enzymes to suppress inflammatory and oxidative stress.

METHODS

Twenty-four patients with obesity and type 2 diabetes receiving combined oral and insulin therapy were randomly assigned to receive either exenatide 10 μg or placebo twice a day for 12 weeks.

RESULTS

Exenatide increased IL-1RA concentration by 61% (from 318 ± 53 to 456 ± 88 pg/mL; P < 0.05). Exenatide treatment also suppressed Keap-1 protein (P < 0.05) and increased messenger RNA expression of NQO-1, glutathione S-transferase PI, heme oxygenase-1, and p21 and increased NAD(P)H dehydrogenase [quinone] 1 protein (P < 0.05) in mononuclear cells.

CONCLUSIONS

Because IL-1RA protects, maintains, and stimulates β-cell function in humans and Nrf-2‒Keap-1‒ARE protects β cells in animals with experimental diabetes, these actions of exenatide may contribute to a potential protective effect on β cells in diabetes.

Diminished androgen and estrogen receptors and aromatase levels in hypogonadal diabetic men: reversal with testosterone

AIMS

One-third of males with type 2 diabetes (T2DM) have hypogonadism, characterized by low total and free testosterone concentrations. We hypothesized that this condition is associated with a compensatory increase in the expression of androgen receptors (AR) and that testosterone replacement reverses these changes. We also measured estrogen receptor and aromatase expression.

MATERIALS AND METHODS

This is a randomized double-blind placebo-controlled trial. Thirty-two hypogonadal and 32 eugonadal men with T2DM were recruited. Hypogonadal men were randomized to receive intramuscular testosterone or saline every 2 weeks for 22 weeks. We measured AR, ERα and aromatase expression in peripheral blood mononuclear cells (MNC), adipose tissue and skeletal muscle in hypogonadal and eugonadal males with T2DM at baseline and after 22 weeks of treatment in those with hypogonadism.

RESULTS

The mRNA expression of AR, ERα (ESR1) and aromatase in adipose tissue from hypogonadal men was significantly lower as compared to eugonadal men, and it increased significantly to levels comparable to those in eugonadal patients with T2DM following testosterone treatment. AR mRNA expression was also significantly lower in MNC from hypogonadal patients compared to eugonadal T2DM patients. Testosterone administration in hypogonadal patients also restored AR mRNA and nuclear extract protein levels from MNC to that in eugonadal patients. In the skeletal muscle, AR mRNA and protein expression are lower in men with hypogonadism. Testosterone treatment restored AR expression levels to that comparable to levels in eugonadal men.

CONCLUSIONS

We conclude that, contrary to our hypothesis, the expression of AR, ERα and aromatase is significantly diminished in hypogonadal men as compared to eugonadal men with type 2 diabetes. Following testosterone replacement, there is a reversal of these deficits.

Incretins: Beyond type 2 diabetes

While the use of incretins, including GLP-1 receptor agonists and PDD-IV inhibitors, is well established in the treatment of type 2 diabetes, many other aspects of these agents are yet to be discovered and utilized for their potential clinical benefit. These include the potential role of GLP-1 receptor agonists in the induction of weight loss, blood pressure reduction, anti-inflammatory and nephro- and cardio-protective actions. Their potential benefit in type 1 diabetes is also being investigated. This review will attempt to comprehensively describe novel discoveries in the field of incretin pathophysiology and pharmacology beyond their classical role in the treatment of type 2 diabetes.

Intranasal Insulin Administration Does Not Affect LH Concentrations in Men with Diabetes

A quarter of men with obesity or type 2 diabetes have hypogonadotropic hypogonadism. Animal studies and in vitro data have shown that insulin action and insulin responsiveness in the brain are necessary for the maintenance of the functional integrity of the hypothalamo-hypophyseal-gonadal axis. We conducted a randomized, placebo-controlled trial to evaluate the effect of one dose of intranasal insulin (40 IU of regular insulin) or saline on LH concentrations in 14 men (8 with type 2 diabetes and 6 healthy lean men). Insulin or saline was administered intranasally on two different occasions, at least one week apart. Blood samples were collected to measure LH concentrations every 15 minutes for 5 hours. Study drug was administered intranasally after a 2-hour baseline sampling period. Patients remained fasting throughout the procedure. The primary endpoint of the study was to compare the change in LH concentrations after intranasal insulin as compared to placebo (intranasal saline). Change was defined as the difference between baseline LH concentrations (average of the 9 samples collected in two hours prior to drug administration) and average LH concentrations following drug administration (average of the 12 samples collected in 3 hours). There was no change in LH concentrations following insulin administration as compared to placebo in men with diabetes or in lean men. We conclude that one dose of 40 IU of regular insulin administered intranasally does not change LH concentrations acutely in men.

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.

Exenatide induces an increase in vasodilatory and a decrease in vasoconstrictive mediators

In view of the known vasodilatory effects of glucagon-like peptide-1 and exenatide, we investigated the effects of exenatide on vasoactive factors. We analysed blood samples and mononuclear cells (MNCs) from a previous study, collected after a single dose and 12 weeks of exenatide or placebo treatment in a series of 24 patients with type 2 diabetes mellitus. After exenatide treatment, plasma concentrations of atrial natriuretic peptide, cyclic guanyl monophosphate (cGMP) and cyclic adenyl monophosphate increased significantly at 12 weeks. Plasma cGMP and adenylate cyclase expression in MNCs increased significantly after a single dose. Angiotensinogen concentration fell significantly 2 hours after a single dose and at 12 weeks, while renin and angiotensin II levels fell significantly only after a single dose and not after 12 weeks of treatment. Exenatide also suppressed the plasma concentration of transforming growth factor-β and the expression of P311 in MNCs at 12 weeks. Thus, exenatide induces an increase in a series of vasodilators, while suppressing the renin-angiotensin system. These changes may contribute to the overall vasodilatory effect of exenatide.

Antiinflammatory 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 fiber's known benefits in the prevention of insulin resistance, type 2 diabetes, and atherosclerosis.

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

CONTEXT

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.

DESIGN

Randomized, double-blind, placebo-controlled trial.

METHODS

We measured basal serum concentrations of erythropoietin, iron, iron binding capacity, transferrin (saturated and unsaturated), ferritin and hepcidin and the expression of ferroportin and transferrin receptor (TR) in peripheral blood mononuclear cells (MNC) of 94 men with type 2 diabetes. Forty-four men had HH (defined as subnormal free testosterone along with low or normal LH concentrations) while 50 were eugonadal. Men with HH were randomized to testosterone or placebo treatment every 2 weeks for 15 weeks. Blood samples were collected at baseline, 3 and 15 weeks after starting treatment. Twenty men in testosterone group and 14 men in placebo group completed the study.

RESULTS

Haematocrit levels were lower in men with HH (41·1 ± 3·9% vs 43·8 ± 3·4%, P = 0·001). There were no differences in plasma concentrations of hepcidin, ferritin, erythropoietin, transferrin or iron, or in the expression of ferroportin or TR in MNC among HH and eugonadal men. Haematocrit increased to 45·3 ± 4·5%, hepcidin decreased by 28 ± 7% and erythropoietin increased by 21 ± 7% after testosterone therapy (P < 0·05). There was no significant change in ferritin concentrations, but transferrin concentration increased while transferrin saturation and iron concentrations decreased (P < 0·05). Ferroportin and TR mRNA expression in MNC increased by 70 ± 13% and 43 ± 10%, respectively (P < 0·01), after testosterone therapy.

CONCLUSIONS

The increase in haematocrit following testosterone therapy is associated with an increase in erythropoietin, the suppression of hepcidin, and an increase in the expression of ferroportin and TR.

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.

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.

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.

A mixed anti-inflammatory and pro-inflammatory response associated with a high dose of corticosteroids

OBJECTIVE

Hydrocortisone, at a low dose (100 mg), induces an anti-inflammatory response including inducing IkBα and suppressing intranuclear NFκB and AP-1 binding and the expression of pro-inflammatory mediators like MMPs. We have now investigated the effect of a high dose of hydrocortisone (300mg=60 mg prednisolone) on NFκB binding and the expression of TLRs, the mediators of TLR signal transduction, MyD88 and TRIF and HMG-B1.

DESIGN AND SUBJECTS

A 300mg of hydrocortisone or saline was injected intravenously in ten normal subjects during 2 separate visits, in a randomized crossover study. Blood samples were obtained at 0, 1, 4, 6 and 24h after the injection and mononuclear cells (MNC) were prepared.

RESULTS

There was a significant increase in glucose (from 92±4 to 116±6 mg/dl), insulin (from 4.5±0.7 to 5.3±0.8 mU/ml) and FFA concentrations (from 0.38±0.1 to 0.80±0.15mM) following the administration of hydrocortisone compared to placebo treatment. While NFκB binding and the mRNA expression of MyD88, TRIF, chemokines and chemokine receptors were suppressed significantly in MNC, there was a paradoxical increase in the mRNA expression of TLR 2, 5 and 9 and HMG-B1 was increased by 103±24%, 107±19%, 56±13% and 58±12% above the baseline, respectively in the MNC. Plasma concentrations of HMG-B1 and MMP-9 increased by 37±12% and 125±22%, respectively, while TNF-α concentrations fell by 27±9%.

CONCLUSION

While this high dose of hydrocortisone exerts a powerful anti-inflammatory effect, it also exerts certain proinflammatory effects mainly on TLRs expression. The known pro-inflammatory effects of glucose and FFAs may have contributed to these effects. These paradoxical pro-inflammatory effects may account for the inability of these drugs to show benefit in clinical trials of septicemia and other severe pro-inflammatory states and might contribute to some of the side effects of corticosteroids use.