Worsening Of Insulin Sensitivity Research Articles

Deficiency of the Hemoglobin-Haptoglobin Receptor, CD163, Worsens Insulin Sensitivity in Obese Male Mice.

Excessive iron accumulation in metabolic organs such as the adipose tissue, liver, and skeletal muscle is associated with increased diabetes risk. Tissue-resident macrophages serve multiple roles including managing inflammatory tone and regulating parachymal iron homeostasis; thus protecting against metabolic dysfunction upon iron overload. The scavenger receptor CD163 is uniquely present on tissue-resident macrophages, and plays a significant role in iron homeostasis by clearing extracellular hemoglobin-haptoglobin complexes, thereby limiting oxidative damage caused by free hemoglobin in metabolic tissues. We show that the absence of CD163 exacerbates glucose intolerance and insulin resistance in male mice with obesity. Additionally, loss of CD163 reduced the expression of iron regulatory genes (Tfr1, Cisd1, Slc40a1) in adipose tissue macrophages and anti-inflammatory (M2-like) bone marrow-derived macrophages (BMDMs). Further, CD163 deficiency mediated a pro-inflammatory shift and limited hemoglobin scavenging specifically in M2-like BMDMs. To this end, iron buffering was diminished in inguinal white adipose tissue (iWAT) macrophages in vivo, which culminated in iron spillover into adipocytes and CD45+CD11B- non-myeloid immune cells in iWAT. These findings show that CD163 on tissue-resident macrophages is critical for their anti-inflammatory and hemoglobin scavenging roles, and its absence results in impaired systemic insulin action in an obese setting.

P179 CARDIOMETABOLIC DYSFUNCTIONS IN THE OFFSPRING OF FRUCTOSE-OVERLOADED RATS: EVIDENCE FOR THE CHOLINERGIC ANTI-INFLAMMATORY REFLEX

Background: Studies have reported an increase in the consumption of processed foods high in fructose (F), which has been associated with the development of metabolic syndrome. The cholinergic anti-inflammatory reflex (CAT) pathway appears to play an important role in this condition. This study investigated the role of the CAT pathway by splenic and vagal denervation (D) and treatment with galantamine (GAL) on cardiometabolic and autonomic parameters in the offspring of rats subjected to chronic fructose consumption. Methods: Wistar rats (parents) were given fructose (10% drinking water) or water for 60 days. The rats were then mated and the fructose overload was maintained for females until the end of lactation. The offspring were randomized into 4 groups (n=10/5 per sex): Control (C), F, F+GAL, and F+D+GAL. GAL (5 mg/kg), an acetylcholinesterase inhibitor, was administered 30 days by gavage. D was performed at 21 days. The offspring were evaluated at 51 days. Results: Compared with the C group (3.63±0.24 mg/dl/%/min), the F and F+D+GAL groups (2.8±0.20 and 2.9±0.14 mg/dl/%/min) had a worsening of insulin sensitivity. The F+GAL (370±79 mg) and F+D+GAL groups (310±75 mg) had reduced adipose tissue compared to the C (708±121 mg) and F (980±160 mg) groups. The F and F+D+GAL groups (vs. C group) had increased mean arterial pressure (AP) (114±1.9 and 115±1.4 vs. 101±2.2mmHg), heart rate (381±5 and 369±5 vs. 343±10bpm), and low frequency component of systolic AP (4.95±0.49 and 3.33±0.23 vs. 1.62±0.2mmHg2). The F+GAL group had an increase in cardiac vagal modulation (HF-PI and RMSSD). F and F+D+GAL groups (vs. C) had impairment of baroreflex (-3.24±0.26 and -3.48±0.1 vs. -3.93±0.1bpm/mmHg), and F+GAL group improved this parameter. Conclusion: Our data provide evidence for the involvement of CAT in cardiometabolic dysfunction in the offspring of parents exposed to chronic fructose consumption. Such findings highlight the importance of therapeutic strategies that improve autonomic modulation to prevent early changes in offspring of metabolically overburdened parents. Financial support: FAPESP(2022/04050-1), CNPq, CAPES-PROSUP.

Deficiency of the hemoglobin-haptoglobin receptor, CD163, worsens insulin sensitivity in obese male mice.

Excessive iron accumulation in metabolic organs such as the adipose tissue, liver, and skeletal muscle is associated with increased diabetes risk. Tissue-resident macrophages serve multiple roles including managing inflammatory tone and regulating parachymal iron homeostasis; thus protecting against metabolic dysfunction upon iron overload. The scavenger receptor CD163 is uniquely present on tissue-resident macrophages, and plays a significant role in iron homeostasis by clearing extracellular hemoglobin-haptoglobin complexes, thereby limiting oxidative damage caused by free hemoglobin in metabolic tissues. We show that the absence of CD163 exacerbates glucose intolerance and insulin resistance in male mice with obesity. Additionally, loss of CD163 reduced the expression of iron regulatory genes (Tfr1, Cisd1, Slc40a1) in adipose tissue macrophages and anti-inflammatory (M2-like) bone marrow-derived macrophages (BMDMs). Further, CD163 deficiency mediated a pro-inflammatory shift and limited hemoglobin scavenging specifically in M2-like BMDMs. To this end, iron buffering was diminished in inguinal white adipose tissue (iWAT) macrophages in vivo, which culminated in iron spillover into adipocytes and CD45+CD11B- non-myeloid immune cells in iWAT. These findings show that CD163 on tissue-resident macrophages is critical for their anti-inflammatory and hemoglobin scavenging roles, and its absence results in impaired systemic insulin action in an obese setting.

THU312 The Type 1 Diabetes Susceptible LEW.1WR1 Rat Develops Insulin Resistance And Severe Non-alcoholic Fatty Liver Disease

Abstract Disclosure: S.T. Love-Rutledge: None. M. Wimalarathne: None. L.D. Mercado: None. A. Smiley: None. C. Apperson: None. Q.C. Vidal: None. A subpopulation of type 1 diabetes patients develop the pathophysiological parameters to be termed double diabetes. This patient population often develops obesity, non-alcoholic fatty liver disease, and other hallmarks of insulin resistance. The LEW.1WR1 rat is a type 1 diabetes susceptible rodent with hyperinsulinemia that has shown signs of fatty liver infiltration1,2. We hypothesized that LEW.1WR1 rats would develop insulin resistance and severe nonalcoholic fatty liver disease due to its increased circulating insulin and predisposition to autoimmune disease. LEW.1WR1 rats and Wistar Furth rats were used for the 18-week long experiment. Peripheral insulin sensitivity was evaluated using insulin tolerance tests at weeks 11 and 17 showing worsening insulin sensitivity as evidenced by the gradual slope compared to the steep slope of the Wistar Furth rats. HOMA-IR values support LEW.1WR1 rats develop worsening insulin sensitivity and are insulin resistant at week 23 of the experiment (2.613± 0.796, p < 0.0001). Terminal liver mass confirmed increased liver mass normalized to body mass and liver triglyceride levels suggested increased ectopic lid accumulation in the liver (Liver Mass 2.65% ±0.32 p = 0.0005 and triglyceride levels 192.8 ± 21.85 mg/dL, p = 0.034). The H&E-stained digital liver slides were scored for liver ballooning, steatosis, and markers of inflammation. Fibrosis and terminal circulating cytokines were also measured to assess severity of condition. While both groups showed increased steatosis and injury ballooning, trichrome blue staining and inflammatory cytokines verify the severity of disease in the LEW.1WR1 rats. LEW rats have increased fibrosis area and high serum TNF-α, IFN-, MCP-1 levels. As hypothesized, we observed that LEW.1WR1 rats show characteristics of insulin resistance and malignant nonalcoholic fatty liver disease development.

Folic acid supplementation in a mouse model of diabetes in pregnancy alters insulin sensitivity in female mice and beta cell mass in offspring.

Epidemiological studies have reported discrepant findings on the relationship between folic acid intake during pregnancy and risk for gestational diabetes mellitus (GDM). To begin to understand how folic acid impacts metabolic health during pregnancy, we determined the effects of excess folic acid supplementation (5× recommendation) on maternal and fetal offspring metabolic health. Using a mouse (female C57BL/6J) model of diet-induced diabetes in pregnancy (western diet) and control mice, we show that folic acid supplementation improved insulin sensitivity in the female mice fed the western diet and worsened insulin sensitivity in control mice. We found no unmetabolized folic acid in liver from supplemented mice suggesting the metabolic effects of folic acid supplementation are not due to unmetabolized folic acid. Male fetal (gestational day 18.5) offspring from folic acid supplemented dams (western and control) had greater beta cell mass and density than those from unsupplemented dams; this was not observed in female offspring. Differential sex-specific hepatic gene expression profiles were observed in the fetal offspring from supplemented dams but this differed between western and controls. Our findings suggest that folic acid supplementation affects insulin sensitivity in female mice, but is dependent on their metabolic phenotype and has sex-specific effects on offspring pancreas and liver.

The Impact of Atorvastatin on Cardiometabolic Risk Factors in Sisters of Women with Polycystic Ovary Syndrome

Introduction: Polycystic ovary syndrome (PCOS) is a frequent endocrinopathy in young women with significantly increased cardiometabolic risk. Siblings of women with this disorder are at increased risk of insulin resistance and androgen excess. The current study was aimed at investigating cardiometabolic effects of atorvastatin in sisters of women with PCOS. Methods: This prospective observational study compared two age-, body mass index-, blood pressure-, and plasma lipid-matched groups of women with hypercholesterolemia: sisters of PCOS probands (group A) and unrelated control subjects (group B), receiving atorvastatin (40 mg daily). Plasma lipids, glucose homeostasis markers, concentrations of sex hormones, high-sensitivity C-reactive protein (hsCRP), homocysteine, fibrinogen and uric acid, and the urinary albumin-to-creatinine ratio (UACR) were measured before entering the study and 6 months later. Results: Both groups differed in the degree of insulin resistance, testosterone, free androgen index (FAI), circulating levels of hsCRP and homocysteine, and UACR. There were no between-group differences in the impact of atorvastatin on plasma lipids. Despite reducing hsCRP and homocysteine in both groups of women, the effect on these biomarkers was stronger in group B than in group A. Only in group B, atorvastatin did reduce fibrinogen, uric acid, and UACR. Only in group A, atorvastatin did worsen insulin sensitivity and tended to reduce testosterone and FAI. The impact of atorvastatin on hsCRP, homocysteine, fibrinogen, uric acid, and UACR inversely correlated with testosterone and FAI. Conclusion: The obtained results suggest that sisters of women with PCOS may benefit to a lesser degree from atorvastatin treatment than other women.

Chronic UCN2 treatment desensitizes CRHR2 and improves insulin sensitivity

Urocortin 2 (UCN2) acts as a ligand for the G protein-coupled receptor corticotropin-releasing hormone receptor 2 (CRHR2). UCN2 has been reported to improve or worsen insulin sensitivity and glucose tolerance in vivo. Here we show that acute dosing of UCN2 induces systemic insulin resistance in male mice and skeletal muscle. Inversely, chronic elevation of UCN2 by injection with adenovirus encoding UCN2 resolves metabolic complications, improving glucose tolerance. CRHR2 recruits Gs in response to low concentrations of UCN2, as well as Gi and β-Arrestin at high concentrations of UCN2. Pre-treating cells and skeletal muscle ex vivo with UCN2 leads to internalization of CRHR2, dampened ligand-dependent increases in cAMP, and blunted reductions in insulin signaling. These results provide mechanistic insights into how UCN2 regulates insulin sensitivity and glucose metabolism in skeletal muscle and in vivo. Importantly, a working model was derived from these results that unifies the contradictory metabolic effects of UCN2.

Gender-affirming hormone therapy decreases d-dimer but worsens insulin sensitivity in transgender women.

Gender-affirming hormonal therapies (GAHT) and HIV increase cardiovascular risk for transgender women (TW), yet there is a paucity of data quantifying cardiometabolic changes following GAHT initiation, particularly among TW with HIV. The Féminas study enrolled TW from October 2016 to March 2017 in Lima, Peru. Participants reported sexual activity that was high risk for HIV acquisition or transmission. All were tested for HIV/ sexually transmitted infection and were given access to GAHT (oestradiol valerate and spironolactone), HIV pre-exposure prophylaxis (PrEP) or antiretroviral therapy (ART) for 12 months. Biomarker measurement was done on stored serum, whereas fasting glucose and lipids were measured in real time. In all, 170 TW (32 with HIV, 138 without HIV) had median age 27 years and 70% prior GAHT use. At baseline, PCSK9, sCD14, sCD163, IL-6, sTNFRI/II, CRP and EN-RAGE levels were significantly higher in TW with HIV than in TW without HIV. High-density lipoprotein and total cholesterol were lower and insulin and glucose parameters were similar. All TW with HIV started ART, but only five achieved virological suppression at any time. No TW without HIV initiated PrEP. Over 6 months, all participants initiated GAHT and had worsening insulin, glucose and HOMA-IR. Large d-dimer decreases also occurred. Similar changes occurred in TW with and without HIV. In this unique cohort of TW, GAHT decreased d-dimer but worsened insulin sensitivity. Because PrEP uptake and ART adherence were very low, observed effects are primarily attributed to GAHT use. Further study is needed to better understand cardiometabolic changes in TW by HIV serostatus.

A Short-Term High-Fat Diet Worsens Insulin Sensitivity with Changes in Metabolic Parameters in Non-Obese Japanese Men.

A short-term high-calorie high-fat diet (HCHFD) impairs insulin sensitivity in non-obese South Asian but not Caucasian men; however, the effect of short-term HCHFD on insulin sensitivity in East Asians is unknown. We recruited 21 healthy non-obese Japanese men to evaluate metabolic parameters and gut microbiota before and after 6-day HCHFD consisting of a regular diet plus a 45% energy excess with dairy fat supplementation. We evaluated tissue-specific insulin sensitivity and metabolic clearance rate of insulin (MCRI) using a two-step hyperinsulinemic euglycemic clamp, glucose tolerance using the glucose tolerance test, and measured ectopic fat in muscle and the liver using ¹H-magnetic resonance spectroscopy. The primary outcome of this study was insulin sensitivity measured by the clamp study. The secondary/exploratory outcomes were other metabolic changes. After HCHFD, levels of circulating lipopolysaccharide binding protein (LBP), a marker of endotoxemia, increased by 14%. In addition, intramyocellular lipid levels in the tibialis anterior and soleus and intrahepatic lipid levels increased by 47%, 31%, and 200%, respectively. Insulin sensitivity decreased by 4% in muscle and 8% in liver. However, even with reduced insulin sensitivity, glucose metabolism was maintained by increased serum insulin concentrations due to lower MCRI and higher endogenous insulin secretion during the clamp. Glucose levels during the meal tolerance test were comparable before and after HCHFD. In conclusion, short-term HCHFD impaired insulin sensitivity in the muscle and livers of non-obese Japanese men with increased LBP and ectopic fat accumulation. Elevated insulin levels from modulated insulin secretion and clearance might contribute to the maintenance of normal glucose metabolism during the clamp and meal tolerance test.

Cardiometabolic Effects of Cabergoline and Combined Oral Contraceptive Pills in Young Women with Hyperprolactinemia: A Pilot Study.

Although dopaminergic agents are the drugs of choice in treatment of prolactin excess, women who cannot be treated with these agents are recommended to receive estrogen preparations. The aim of this study was to compare cardiometabolic effects of both treatment options. The study population included three groups of young women. Subjects with mild-to-moderate hyperprolactinemia received either low-dose cabergoline or oral combined contraceptives (ethinyl estradiol plus desogestrel), while normoprolactinemic women were drug-naive. Plasma prolactin, glucose homeostasis markers, lipids, circulating levels of uric acid, high-sensitivity C-reactive protein (hsCRP), fibrinogen and homocysteine, and the urinary albumin-to-creatinine ratio (UACR) were assessed at entry and six months later. Hyperprolactinemic women differed from normoprolactinemic ones in glucose homeostasis markers, high-density lipoprotein (HDL)-cholesterol, triglycerides, uric acid, hsCRP, fibrinogen, homocysteine and UACR. Cabergoline decreased total and monomeric prolactin levels, which was accompanied by normalization of glucose, insulin sensitivity, glycated hemoglobin, HDL-cholesterol, triglycerides, uric acid, hsCRP, fibrinogen, homocysteine and UACR. Despite a neutral effect on prolactin levels, combined contraceptives worsened insulin sensitivity and increased triglycerides, hsCRP, fibrinogen and UACR. At follow-up, cabergoline-treated women were characterized by a better cardiometabolic profile than women receiving ethinyl estradiol plus desogestrel. Our findings suggest that only cabergoline reduces cardiometabolic risk in young women with hyperprolactinemia.

Visceral fat correlates with insulin secretion and sensitivity independent of BMI and subcutaneous fat in Chinese with type 2 diabetes.

Clinical heterogeneity exists in overall obesity and abdominal obesity in terms of insulin secretion and sensitivity. Further, the impact of visceral fat (VF) on the first- and second-phase insulin secretion (FPIS and SPIS) is controversial. We aim to investigate insulin secretion and sensitivity in Chinese patients with T2DM according to different BMI and VF levels. This study enrolled 300 participants. A dual bioelectrical impedance analyzer was used to assess the visceral and subcutaneous fat area (VFA and SFA). VF levels were categorized as normal or high, with the cutoff value of 100 cm2. FPIS and SPIS were evaluated by arginine stimulation test and standardized steamed bread meal tolerance test, respectively. β-cell function (HOMA2-β), insulin resistance (HOMA2-IR), and Gutt's insulin sensitivity index (Gutt-ISI) were also calculated. Spearman's correlation analysis and multivariate linear regression analysis were adopted for statistical analysis. Participants were categorized into four groups: normal weight-normal VF, normal weight-high VF, overweight/obese-normal VF and overweight/obese-high VF. Multivariate linear regression showed that both VFA and SFA were correlated with FPIS, HOMA2-IR and Gutt-ISI after controlling for gender and diabetes duration. After further adjustment for BMI and VFA, some associations of SFA with insulin secretion and sensitivity disappeared. After adjustment for gender, diabetes duration, BMI and SFA, VFA was positively correlated with FPIS, SPIS and HOMA2-IR. Subjects with overweight/obese-high VF were more likely to have higher FPIS, HOMA2-IR and lower Gutt-ISI (all p < 0.05). VF affects both FPIS and SPIS, and worsens insulin sensitivity independent of BMI and subcutaneous fat in Chinese patients with T2DM. http://www.chictr.org.cn, identifier ChiCTR2200062884.

Menstrual Cycle, Glucose Control and Insulin Sensitivity in Type 1 Diabetes: A Systematic Review

The correlation between the menstrual cycle and glucose control in type 1 diabetes has been the focus of several studies since the 1920s, but a few critical aspects made it particularly challenging to reach conclusive evidence. The aim of this systematic review is to reveal more solid information about the impact of the menstrual cycle on glycaemic outcomes and insulin sensitivity in type 1 diabetes and highlight the less researched areas. The literature was searched by two authors independently using PubMed/MEDLINE, Embase and Scopus (last search on 2 November 2022). The retrieved data did not allow us to perform a meta-analysis. We included 14 studies published between 1990 and 2022, with sample sizes from 4 to 124 patients. We found a wide heterogeneity in the definition of the menstrual cycle phases, glucose metrics, techniques for determining insulin sensitivity, hormonal assessment and other interfering factors considered, with an overall high risk of bias. There is no conclusive evidence, and published data do not allow us to achieve quantitative results. In a subset of patients, a possible worsening of insulin sensitivity and hyperglycaemia in the luteal phase could be observed. From the clinical standpoint, a cautious strategy based on patient-specific patterns can be considered until new, solid evidence is obtained.

Limited evidence for sympathetic neural overactivation in older patients with type 2 diabetes mellitus.

Mechanistic studies suggested that excess sympathetic activity promotes arterial hypertension while worsening insulin sensitivity. Older patients with type 2 diabetes are at particularly high cardiovascular and metabolic risk. However, data on sympathetic activity in this population is scarce. We studied 61 patients with type 2 diabetes mellitus (22 women, 60.9 ± 1.4 years; 39 men, 60.9 ± 1.4 years). They had to have diabetes for at least 2 years, a hemoglobin A1c of 6.5-10%, a body-mass-index of 20-40 kg/m2, and had to be treated with stable doses of metformin only. We recorded ECG, finger and brachial blood pressure, and muscle sympathetic nerve activity (MSNA). MSNA was 37.5 ± 2.5 bursts/min in women and 39.0 ± 2.0 bursts/min in men (p = 0.55). MSNA expressed as burst incidence was 52.7 ± 2.0 bursts/100 beats in women and 59.2 ± 3.1 bursts/100 beats in men (p = 0.21). Five out of 39 men (12.8%) and two out of 22 women (9.1%) exhibited resting MSNA measurements above the 95th percentile for sex and age. In the pooled analysis, MSNA was not significantly correlated with systolic blood pressure, diastolic blood pressure, body mass index, waist circumference, body composition, or HbA1c (r 2 < 0.02, p > 0.26 for all). We conclude that relatively few older patients with type 2 diabetes mellitus exhibit increased MSNA. The large interindividual variability in MSNA cannot be explained by gender, blood pressure, body mass index, or glycemic control.

Cabergoline-Induced Hypoprolactinemia May Attenuate Cardiometabolic Effects of Atorvastatin: A Pilot Study

Introduction: Hypoprolactinemia, which is usually a consequence of treatment with inadequate high doses of dopaminergic agents, is a poorly understood clinical condition. The aim of the current study was to investigate whether the cardiometabolic effects of statin therapy differ between patients with low prolactin production and patients with normal levels of this hormone. Methods: We studied two groups of cabergoline-treated premenopausal women with hypercholesterolemia matched for age, plasma lipids, cabergoline dose, and treatment duration: 11 women with hypoprolactinemia (group A) and 15 women with plasma levels of this hormone within the reference range (group B). The control group (C) included 25 dopaminergic-naïve normoprolactinemic women, matched for age and lipid levels. Plasma lipids, insulin sensitivity, and levels of uric acid, high-sensitivity C-reactive protein (hsCRP), fibrinogen, homocysteine, and 25-hydroxyvitamin D were measured before and after 14-week treatment with atorvastatin (20 mg daily). Results: Patients with hypoprolactinemia were more insulin-resistant, had lower values of total testosterone and free androgen index, and had higher levels of hsCRP and fibrinogen than individuals with normal prolactin levels. Although atorvastatin reduced total and LDL cholesterol and hsCRP in all study groups, this effect was stronger in groups B and C than in group A. Only in groups B and C, the drug decreased uric acid, fibrinogen, and homocysteine and increased 25-hydroxyvitamin D. In turn, only in group A, atorvastatin worsened insulin sensitivity and reduced free androgen index. Conclusion: Coexisting hypoprolactinemia may have an unfavorable impact on the pleiotropic effects of statins.

A high-fat diet disrupts the hepatic and adipose circadian rhythms and modulates the diurnal rhythm of gut microbiota-derived short-chain fatty acids in gestational mice.

The prevalence of gestational obesity has reached epidemic proportions. Evidence supported that the interactions between the gut microbiota and circadian clocks far reached, affecting host metabolism. Our study aimed to investigate the effect of a high-fat diet (HF) on the hepatic and adipose circadian rhythms in gestational mice and to explore the role of gut microbiota-derived short-chain fatty acids (SCFAs) in mediating the effects. C57BL/6 female mice were randomly fed a standard chow diet (Ctr) or HF prior to and during pregnancy. Samples were collected every 4 h over 24 h (six time points), and 16S rRNA and metabonomics were carried out. Rhythmic patterns were identified and compared using CircaCompare. The results showed that the HF before and during pregnancy significantly induced obesity and worsen glucose tolerance, insulin sensitivity, and lipid metabolism in the gestational mice. Furthermore, the HF significantly disrupted the rhythmic pattern of hepatic and adipose circadian clock genes and downstream metabolic genes. Importantly, our results revealed that the HF altered the diurnal rhythm of the gut microbiota in a diverse manner, which was assessed across three categories: phase shift, loss rhythmicity, and gained rhythmicity. We report here, for the first time, a parallel alteration of the rhythmic phase of butyric acid and butyrate-producing Clostridiaceae_1, which was confirmed by a positive correlation between them. Overall, our research emphasized the importance of the rhythmicity of gut microbiota-derived SCFAs in mediating circadian disruption in response to the HF in gestational mice, which may provide novel insights into the prevention and treatment of gestational obesity.

Association of Dietary Acid Load with Insulin Sensitivity Index among Apparently Healthy Nigerians

The possible role of regular consumption of diets with high acid forming potential in decreasing cellular sensitivity to insulin and its associated complications has been investigated. However, findings across different study groups are conflicting. It is likely that the association is affected by genetic and environmental factors that differ among different populations. We investigated the impact of diet-induced acidosis on the degree of insulin sensitivity among apparently healthy adult Nigerians. Assessment of dietary intake was done using a semi-quantitative food frequency questionnaire and the Nigerian Food Composition Table. Acid forming potential of our local diets were estimated as Potential Renal Acid Load (PRAL) scores. Fasting plasma glucose and insulin were measured. Degree of insulin sensitivity was calculated as Quantitative Insulin Sensitivity Check Index (QUICKI). About 35 (16.2%) of the study subjects were observed to have insulin resistance. Across the study groups, there was a statistically significant trend with higher intake of dietary acid associated with decreased insulin sensitivity (p for trend &lt; 0.05). We conclude that among apparently healthy adult subjects in this study, regular consumption of diets with high acid forming potential might be linked with worsening of insulin sensitivity.

Angiotensin‐(1‐7) Mas Receptors Localized to Proopiomelanocortin Neurons Tonically Regulate Insulin Sensitivity

Angiotensin (Ang)‐(1‐7), a protective hormone of the renin‐angiotensin system, has emerged as a novel target to improve cardiovascular and metabolic functions in animal models. In addition to blood pressure lowering effects, recent studies from our laboratory and others have shown that Ang‐(1‐7) can promote insulin sensitization and weight loss in obese rodents. Our recent preliminary findings suggest these effects are centrally‐mediated, with Ang‐(1‐7) mas receptors (MasR) widely distributed to the arcuate nucleus of the hypothalamus. In particular, we found that MasR are highly colocalized with proopiomelanocortin (POMC)‐containing neurons in this brain region, neurons which when activated reduce food intake and increase energy expenditure to promote weight loss as well as improve insulin sensitivity. The importance of MasR localized to POMC neurons in metabolic functions, however, is currently unknown. In this study, we tested the hypothesis MasR expressed in POMC neurons are important for normal control of energy balance and glucose homeostasis. To test this, mice containing conditional knockout alleles of the Ang‐(1‐7) MasR were crossed with POMC‐Cre mice to specifically delete MasR from POMC neurons (POMCMasR‐KO). Body mass and composition, insulin sensitivity, and glucose tolerance were measured in male and female POMCMasR‐KO mice and wild‐type littermates (n=6‐11/group) at 8 weeks of age on a standard chow diet. Despite similar fasting glucose and insulin levels, male POMCMasR‐KO mice had worsened insulin sensitivity compared with wild‐type littermates (area under the curve for decrease in glucose from baseline in response to intraperitoneal insulin: ‐2134±1071 vs. ‐6531±1507, respectively; p=0.029), with no differences in body mass, adiposity, lean mass, or glucose tolerance. In female mice, there was no effect of POMC MasR deletion on any of the metabolic outcomes tested. These findings suggest that MasR localized to POMC neurons provide tonic and sex‐specific modulation of insulin sensitivity in mice. Additional studies are needed to determine if altered MasR signaling in POMC neurons could contribute to insulin resistance in disease states such as obesity and type II diabetes.

Hypothalamic-pituitary-gonadal axis and sexual functioning in metformin-treated men after discontinuation of testosterone replacement therapy: A pilot study.

Metformin was found to reduce elevated gonadotropin levels. The aim of the present study was to determine whether metformin modulates the impact of discontinuation of testosterone therapy on hypothalamic-pituitary-gonadal axis activity and sexual function in men with low testosterone levels. The study included 28men with late-onset hypogonadism (defined according to the criteria of the European Male Aging Study group) receiving testosterone undecanoate (120mg in three equal doses), 12 of whom had been treated with oral metformin (1.7-3g daily). Both testosterone and metformin had been administered for at least six months before enrolment. In all patients, testosterone replacement required to be discontinued. The control group included 16 testosterone- and metformin-treated men with late-onset hypogonadism who during the entire study period continued their treatment. Glucose homeostasis markers, as well as plasma levels of insulin, gonadotropins, testosterone, calculated bioavailable testosterone, dehydroepiandrosterone-sulphate, oestradiol, thyrotropin, free thyroxine, prolactin, insulin-growth factor-1 and cortisol were measured at the beginning of the study and four months later. Moreover, at the beginning and the end of the study, all enrolled patients completed a questionnaire assessing their sexual functioning (IIEF-15). Discontinuation of testosterone therapy resulted in a decrease in total testosterone and bioavailable testosterone (by 42% and 45% in metformin-treated patients, and by 52% and 54% in metformin-naïve patients), as well as impaired all aspects of male sexual function. Changes in bioavailable testosterone, as well as in erectile function, orgasmic function and sexual desire were less pronounced if subjects received metformin. Only in metformin-naïve men, follow-up FSH and LH levels were higher than at baseline (by 75% and 62%). Moreover, discontinuation of testosterone therapy in metformin-naïve men increased glycated haemoglobin, as well as worsened insulin sensitivity. There were no differences between baseline and follow-up levels of the remaining hormones. In metformin-naïve subjects, the increase in gonadotropin levels correlated with the changes in testosterone levels and insulin sensitivity. No effect on glucose homeostasis markers, hormone levels and sexual functioning was observed in the control group. The obtained results suggest that metformin treatment mitigates the unfavourable effect of discontinuation of testosterone treatment on hypothalamic-pituitary-testicular axis activity and sexual function in men with late-onset hypogonadism.

Abstract 58: Angiotensin-(1-7) Mas Receptors In The Arcuate Nucleus Of The Hypothalamus Protect Against High Fat Diet-induced Insulin Resistance In Female Mice

Angiotensin (Ang)-(1-7) is a protective hormone of the renin-angiotensin system that improves insulin sensitivity, glucose tolerance, and energy balance in obese rodents. Our recent findings suggest that Ang-(1-7) activates mas receptors (MasR) in the arcuate nucleus of the hypothalamus (ARC), a brain region critical to control of energy balance and glucose homeostasis, to induce these positive metabolic effects. The distribution of MasR in the ARC and their role in metabolic regulation, however, is unknown. We hypothesized: (1) MasR are expressed in the ARC; and (2) deletion of ARC MasR leads to worsened metabolic outcomes following high fat diet (HFD). To test this, male and female C57Bl/6J mice were fed a 60% HFD or matched control diet ad libitum for 12 weeks. RNAscope in situ hybridization was performed on coronal ARC sections in rostral-middle-caudal regions to determine percentage of MasR positive neurons (n=5/group). In a second experiment, we assessed body composition and insulin and glucose tolerance in transgenic mice with deletion of MasR in ARC neurons (MasR-flox with AAV5-hsyn-GFP-Cre). RNAscope revealed a wide distribution on MasR-positive cells throughout the rostral to caudal extent of the ARC. The average percentage of MasR positive neurons was increased in females versus males, with HFD tending to increase MasR expression in both sexes (control diet male: 11±2; control diet female: 17±3; HFD male: 15±5; HFD female: 24±2; p sex : 0.030; p diet : 0.066; p int : 0.615; two-way ANOVA). Deletion of MasR in ARC neurons worsened insulin sensitivity in HFD but not control diet females (area under the curve for change in glucose from baseline: -1989±1359 HFD control virus vs. 2530±1762 HFD Cre virus; p=0.016), while fasting glucose, glucose tolerance, and body composition did not change. There was no effect of ARC MasR deletion on metabolic outcomes in control diet or HFD male mice. These findings suggest females have more MasR positive neurons in the ARC compared to males, which may be a sex-specific protective mechanism for glucose homeostasis. While further studies are needed to explore the role of ARC MasR in metabolic regulation, these findings support targeting Ang-(1-7) as an innovative strategy in obesity.

CLINICAL, METABOLIC, ENDOCRINE AND SONOGRAPHIC CHARACTERISTICS OF OBESE ADOLESCENT WITH PCOS

Introduction- PCOS is a complex metabolic, endocrinopathy and reproductive disorder that results in the production of androgens and is associated with insulin resistance. Adolescents with PCOS are more obese than normal adolescents and have an increased risk of metabolic syndrome. In obese adolescent increasing abdominal adiposity, worsening insulin sensitivity and Dyslipoproteinemiadyslipoproteinemia give rise to NAFLD in adulthood. This study aimed to investigate the association between PCOS, obesity, NAFLD and Metabolic syndrome in adolescents with PCOS. MATERIALAND METHOD- Retrospective study of 24 obese adolescent PCOS patients. with mean BMI 32.89 kg/m2. Data were taken from 1st January 2015 to 31st December 2020. PCOS patients were diagnosed according to Rotterdam 2003 criteria. Data were collected from the medical records of the patients including clinical history, height, weight, blood pressure, waist circumference and Modied Ferriman-Gallway score for hirsutism. Laboratory values were obtained ultrasound nding of polycystic ovarian disease and fatty liver were obtained from the records. RESULTS:- 2 In our study, the mean age was 15.2 yr The mean body mass index was 32.89 kg/m and the mean age of menarche was 12.3 yr. Hirsutism was present in 75% by modied FG Score system, Family history of PCOS was present in 29.16%, Family history of Cardiovascular disease was present in 12.5%. Afamily history of diabetes mellitus was present in 20.83%. The majority 87.5% of the obese adolescent girl's were presented with menstrual problems. mostly 70.83% with a history of Oligomenorrhea. Waist circumference, &gt;0.80 was present in 87.5%, 50% of patients were hypertensive. 20.83% were prediabetes, 54.16% of patients were found to have dyslipidaemia and 45.83% of patients had Metabolic syndrome. In our mean LH was 10.6 IU/L, mean FSH was 5.8 IU/L, mean Serum testosterone 18.5 ng/ml, mean Serum prolactin was 21.2 ng/mL and mean Serum TSH was 3.3 µIU/mL.75 % of patients had Polycystic appearing ovarian morphology in USG.45.83 % of obese PCOS patient had NAFLD in USG and 33.33% of obese patients had abnormal liver enzymes with NAFLD in USG nding. CONCLUSION:-In our study, we found both metabolic syndrome and NAFLD were frequent in patients with obese adolescent PCOS conrming a relevant clinical association between these three conditions. This study highlights the importance of preventing obesity during the management of adolescent PCOS. The importance of obesity counselling in obese adolescent women is a must to reduce the risks associated with metabolic syndrome. The therapeutic intervention combined with lifestyle modication may provide better treatment for adolescent PCOS.