Relevance of KISS1 gene polymorphisms in susceptibility to polycystic ovary syndrome and its associated endocrine and metabolic disturbances.

Background: Variations in KISS1 may be an emerging factor in polycystic ovary syndrome (PCOS) We hypothesised links between KISS1 polymorphisms in PCOS and its associated endocrine and metabolic disturbances. Methods: The study included 104 PCOS women and 109 controls. Endocrine (kisspeptin, LH, FSH, LH-FSH ratio, oestradiol) and metabolic (cholesterol, triglycerides, HDL, LDL, insulin and glucose) parameters were measured. PCR and nucleotide sequencing were carried out to screen single nucleotide polymorphisms (SNPs) of KISS1. Endocrine and metabolic parameters of PCOS women were compared in the genotypes. Results: Three novel SNPs (rs1213704663C>G, rs1481572212T>G and rs775770652G>A) were detected in KISS1. Of these SNPs, the genotype and allele frequencies of rs1213704663C>G were all significantly associated p<0.001 with PCOS. The LH and oestradiol hypersecretion, and increased LH-FSH ratio of PCOS women were significantly influenced by the GG genotype of rs1213704663, but, this SNP did not influence kisspeptin levels. The other two SNPs rs1481572212T>G and rs775770652G>A exhibited no clinical significance. Conclusion: rs1213704663C>G variation in KISS1 is linked to PCOS and its associated endocrine and metabolic disturbances (LH and oestradiol hypersecretion, and increased LH/FSH).

How Western Diet And Lifestyle Drive The Pandemic Of Obesity And Civilization Diseases.

Westernized populations are plagued by a plethora of chronic non-infectious degenerative diseases, termed as "civilization diseases", like obesity, diabetes, cardiovascular diseases, cancer, autoimmune diseases, Alzheimer's disease and many more, diseases which are rare or virtually absent in hunter-gatherers and other non-westernized populations. There is a growing awareness that the cause of this amazing discrepancy lies in the profound changes in diet and lifestyle during recent human history. This paper shows that the transition from Paleolithic nutrition to Western diets, along with lack of corresponding genetic adaptations, cause significant distortions of the fine-tuned metabolism that has evolved over millions of years of human evolution in adaptation to Paleolithic diets. With the increasing spread of Western diet and lifestyle worldwide, overweight and civilization diseases are also rapidly increasing in developing countries. It is suggested that the diet-related key changes in the developmental process include an increased production of reactive oxygen species and oxidative stress, development of hyperinsulinemia and insulin resistance, low-grade inflammation and an abnormal activation of the sympathetic nervous system and the renin-angiotensin system, all of which play pivotal roles in the development of diseases of civilization. In addition, diet-related epigenetic changes and fetal programming play an important role. The suggested pathomechanism is also able to explain the well-known but not completely understood close relationship between obesity and the wide range of comorbidities, like type 2 diabetes mellitus, cardiovascular disease, etc., as diseases of the same etiopathology. Changing our lifestyle in accordance with our genetic makeup, including diet and physical activity, may help prevent or limit the development of these diseases.

Insulin resistance and insulin hypersecretion in the metabolic syndrome and type 2 diabetes: Time for a conceptual framework shift.

While few dispute the existence of the metabolic syndrome as a clustering of factors indicative of poor metabolic health, its utility above that of its individual components in the clinical care of individual patients is questioned. This is likely a consequence of the failure of clinicians and scientists to agree on a unifying mechanism to explain the metabolic syndrome. Insulin resistance has most commonly been proposed for this role and is generally considered to be a root causative factor for not only metabolic syndrome but also for its associated conditions of non-alcoholic fatty liver disease (NAFLD), polycystic ovary syndrome (PCOS), obesity-related type 2 diabetes (T2D) and atherosclerotic cardiovascular disease (ASCVD). An alternative view, for which evidence is mounting, is that hyper-responsiveness of islet ß-cells to a hostile environment, such as westernised lifestyle, is primary and that the resulting hyperinsulinaemia drives the other components of the metabolic syndrome. Importantly, within this new conceptual framework, insulin resistance, while always a biomarker and state of poor metabolic health, is not considered to be harmful, but a protective adaptive response of critical tissues including the myocardium against insulin-induced metabolic stress. This major shift in how metabolic syndrome can be considered puts insulin hypersecretion into position as the unifying mechanism. If shown to be correct, this new conceptual framework has major implications for the future prevention and management of the metabolic syndrome, including its associated conditions of NAFLD, PCOS, obesity-related T2D and ASCVD.

Developmental exposure to a very low dose of bisphenol A induces persistent islet insulin hypersecretion in Fischer 344 rat offspring.

BACKGROUND: In children with obesity, accentuated insulin secretion has been coupled with development of type 2 diabetes mellitus (T2DM). Bisphenol A (BPA) is a chemical with endocrine- and metabolism-disrupting properties which can be measured in a majority of the population. Exposure to BPA has been associated with the development of metabolic diseases including T2DM. OBJECTIVE: The aim of this study was to investigate if exposure early in life to an environmentally relevant low dose of BPA causes insulin hypersecretion in rat offspring. METHODS: Pregnant Fischer 344 rats were exposed to 0.5 (BPA0.5) or 50 (BPA50) µg BPA/kg BW/day via drinking water from gestational day 3.5 until postnatal day 22. Pancreata from dams and 5- and 52-week-old offspring were procured and islets were isolated by collagenase digestion. Glucose-stimulated insulin secretion and insulin content in the islets were determined by ELISA. RESULTS: Basal (5.5 mM glucose) islet insulin secretion was not affected by BPA exposure. However, stimulated (11 mM glucose) insulin secretion was enhanced by about 50% in islets isolated from BPA0.5-exposed 5- and 52-week-old female and male offspring and by 80% in islets from dams, compared with control. In contrast, the higher dose, BPA50, reduced stimulated insulin secretion by 40% in both 5- and 52-week-old female and male offspring and dams, compared with control. CONCLUSION: A BPA intake 8 times lower than the European Food Safety Authority's (EFSA's) current tolerable daily intake (TDI) of 4 µg/kg BW/day of BPA delivered via drinking water during gestation and early development causes islet insulin hypersecretion in rat offspring up to one year after exposure. The effects of BPA exposure on the endocrine pancreas may promote the development of metabolic disease including T2DM.

Palmitate-Induced Insulin Hypersecretion and Later Secretory Decline Associated with Changes in Protein Expression Patterns in Human Pancreatic Islets.

In obese children with high circulating concentrations of free fatty acid palmitate, we have observed that insulin levels at fasting and in response to a glucose challenge were several times higher than in obese children with low concentrations of the fatty acid as well as in lean controls. Declining and even insufficient insulin levels were observed in obese adolescents with high levels of the fatty acid. In isolated human islets exposed to palmitate we have observed insulin hypersecretion after 2 days exposure. In contrast, insulin secretion from the islets was reduced after 7 days culture in the presence of the fatty acid. This study aims at identifying islet-related biological events potentially linked with the observed insulin hypersecretion and later secretory decline in these obese children and adolescents using the islet model. We analyzed protein expression data obtained from human islets exposed to elevated palmitate levels for 2 and 7 days by an improved methodology for statistical analysis of differentially expressed proteins. Protein profiling of islet samples by liquid chromatography-tandem mass spectrometry identified 115 differentially expressed proteins (DEPs). Several DEPs including sorcin were associated with increased glucose-stimulated insulin secretion in islets after 2 days of exposure to palmitate. Similarly, several metabolic pathways including altered protein degradation, increased autophagy, altered redox condition, and hampered insulin processing were coupled to the functional impairment of islets after 7 days of culture in the presence of palmitate. Such biological events, once validated in the islets, may give rise to novel treatment strategies aiming at normalizing insulin levels in obese children with high palmitate levels, which may reduce or even prevent obesity-related type 2 diabetes mellitus.

Role of fatty liver in the association between obesity and reduced hepatic insulin clearance.

AIM: Hepatic insulin clearance (HIC) is important in regulating plasma insulin levels. Diminished HIC causes inappropriate hyperinsulinaemia, and both obesity and fatty liver (FL), which are known to decrease HIC, can be found either together in the same patient or on their own. The mechanism by which obesity reduces HIC is presumed to be mediated by FL. However, few reports have examined the role of FL in the relationship between obesity and HIC in type 2 diabetes (T2D) patients. Therefore, our study investigated the association of HIC with clinical factors, including insulin sensitivity indices, focusing on the presence or absence of FL and obesity in T2D patients. METHOD: Baseline data from 419 patients with T2D (279 men, 140 women; mean age: 57.6 years; body mass index: 25.5kg/m2) controlled by diet and exercise were analyzed. HIC was calculated from the ratio of fasting c-peptide to fasting insulin levels (HICCIR). Correlation analyses between HICCIR and clinical variables were performed using Pearson's product-moment correlation coefficients and single regression analysis in all participants and in those with obesity and FL either alone or in combination. RESULTS: HICCIR was significantly correlated with whole-body insulin sensitivity indices and influenced by FL, but only in the FL group was obesity independently influenced HIC level. HICCIR decreased in those with both FL and obesity compared with those with only one such complication. CONCLUSION: HICCIR may be used to evaluate whole-body insulin sensitivity in T2D. Also, compared with obesity, the influence of FL strongly contributed to a reduced HIC. TRIAL REGISTRATION NUMBER: These trials were registered by the Japan Pharmaceutical Information Centre clinical trials information (JapicCTI) as 101349 and 101351.

Metabolic consequences of the incorporation of a Roux limb in an omega loop (mini) gastric bypass: evaluation by a glucose tolerance test at mid-term follow-up.

BACKGROUND: In the technique used in our department, Roux-en-Y gastric bypass (RYGB) anatomically only differs from the mini- or omega loop gastric bypass (OLGB) by the incorporation of an isolated alimentary limb, called the Roux limb. The metabolic consequences of the incorporation of a Roux limb are unknown. OBJECTIVES: To evaluate differences in glucose and insulin dynamics between RYGB and OLGB in normoglycemic patients, by submitting them to a glucose challenge after stabilization of their weight. METHODS: Nondiabetic patients who had undergone OLGB 4 years earlier were matched with nondiabetic patients who had undergone RYGB around the same time and with healthy controls. Participants underwent oral (OGTT) and intravenous glucose tolerance test (IVGTT). Endpoints of the study were: progression of plasma glucose and insulin, changes in their concentration [calculated by area under the curve (AUC)] at OGTT and IVGTT, incretin effect and incidence of hypoglycemia. RESULTS: Each of the three groups comprised 14 participants. At OGTT, plasma glucose and insulin incremental values were comparable after OLGB and RYGB, and substantially higher than in controls. Overall glucose concentration, however, did not vary across the three groups. Thirty-minute and overall insulin plasma concentration, indicators of early and total insulin secretion, respectively, was significantly higher in both bypass groups than in controls, and was greatest in OLGB. Severe hypoglycemia occurred in one out of two patients in both bypass groups. At IVGTT, no differences were registered across the three groups and no participant experienced hypoglycemia. The incretin effect was higher after OLGB than after RYGB, but the difference was not statistically significant. CONCLUSIONS: The incorporation of a Roux limb in a loop gastric bypass appears to create a statistically nonsignificant tendency toward reducing insulin hypersecretion observed at OGTT after OLGB, and consequently toward tapering the incretin effect.