Missense variant in insulin receptor (Y1355H) segregates in family with fatty liver disease.

A missense variant in the cytoplasmic domain of the insulin receptor (INSR) was identified by exome sequencing in affected members of a four-generation family with fatty liver disease (FLD). The variant (rs766457461, c.4063T>C, p.Y1355H) results in the substitution of histidine for a tyrosine that undergoes autophosphorylation in response to insulin stimulation in vitro. Because insulin promotes lipogenesis in hepatocytes, we hypothesized that the variant was causally linked to FLD in the family. To test this hypothesis, we used CRISPR/Cas9 technology to replace the corresponding tyrosine in mouse INSR with histidine (Y1345H). No significant differences were found in hepatic insulin signaling, as assessed by phosphorylation of INSR or AKT levels or in activation of the insulin-responsive transcription factor SREBP-1c. Glucose tolerance and hepatic triglyceride (TG) content in Insr1345H/H mice fed a chow diet or diets rich in fat, sucrose or fructose did not differ significantly from WT littermates. Thus, our studies in mice failed to support the notion that INSR (Y1355H) is causally related to FLD in the family or that phosphorylation of this residue alters hepatic TG metabolism.

Increased ß-site APP cleaving enzyme 1-mediated insulin receptor cleavage in type 2 diabetes mellitus with cognitive impairment.

INTRODUCTION: Patients with type 2 diabetes mellitus (T2DM) are at a high risk of cognitive impairment, with insulin resistance playing a pivotal role. ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) is considered a predictor of Alzheimer's disease. However, the potential roles of BACE1 in insulin resistance and the risk of cognitive impairment in T2DM remain unclear. METHODS: We measured plasma BACE1 levels, BACE1 cleavage activities for Swedish mutant amyloid precursor protein (APPsw) and insulin receptor ß subunit (INSR-ß), and soluble INSR (sINSR) levels in a clinical cohort study. RESULTS: T2DM patients with or without cognitive impairment exhibited elevated plasma BACE1 levels and BACE1 enzymatic activities for APPsw and INSR-ß, and sINSR levels. Moreover, the glycemic status correlated with elevated BACE1 levels and BACE1-mediated INSR cleavage, which was associated with insulin resistance. DISCUSSION: The elevated BACE1 levels in T2DM may contribute to increasing the cognitive impairment risk through both amyloidogenesis and insulin resistance.

El receptor soluble de insulina y el síndrome metabólico.

The metabolic syndrome describes a group of signs that increase the likelihood for developing type 2 diabetes mellitus, cardiovascular diseases and some types of cancer. The action of insulin depends on its binding to membrane receptors on its target cells. We wonder if blood insulin could travel bound to proteins and if, in the presence of hyperinsulinemia, a soluble insulin receptor might be generated. We used young adult Wistar rats (which have no predisposition to obesity or diabetes), whose drinking water was added 20 % of sugar and that were fed a standard diet ad libitum for two and six months. They were compared with control rats under the same conditions, but that had running water for consumption. At two months, the rats developed central obesity, moderate hypertension, high triglyceride levels, hyperinsulinemia, glucose intolerance and insulin resistance, i.e. metabolic syndrome. Electrophoresis of the rats' plasma proteins was performed, followed by Western Blot (WB) for insulin and for the outer portion of the insulin receptor. The bands corresponding to insulin and to the receptor external part were at the same molecular weight level, 25-fold higher than that of free insulin. We demonstrated that insulin, both in control animals and in those with hyperinsulinemia, travels bound to the receptor outer portion (ectodomain), which we called soluble insulin receptor, and that is released al higher amounts in response to plasma insulin increase; in rats with metabolic syndrome and hyperinsulinemia, plasma levels are much higher than in controls. Soluble insulin receptor increase in blood might be an early sign of metabolic syndrome.

El síndrome metabólico es un conjunto de signos que aumentan la probabilidad de desarrollar diabetes mellitus tipo 2, enfermedades cardiovasculares y algunos tipos de cáncer. La acción de la insulina depende de su unión a los receptores en la membrana de sus células diana. Para responder a la pregunta de si la insulina en la sangre podría viajar unida a proteínas y si en presencia de hiperinsulinemia podría generarse un receptor soluble de insulina, utilizamos ratas wistar (no tienen predisposición a la obesidad ni a la diabetes), adultas jóvenes, a cuya agua de consumo se adicionó 20 % de azúcar y a las que se les administró dieta estándar ad libitum, durante dos y seis meses; fueron comparadas con ratas control que tuvieron las mismas condiciones, pero con agua corriente para consumo. A los dos meses, las ratas desarrollaron obesidad central, hipertensión moderada, triglicéridos altos, hiperinsulinemia, intolerancia a la glucosa y resistencia a la insulina, es decir, síndrome metabólico. Se realizó electroforesis de las proteínas del plasma de las ratas, seguida de Western Blot para insulina y para la porción externa del receptor de insulina. Las bandas correspondientes a la insulina y la parte externa del receptor estaban al mismo nivel de peso molecular, 25 veces mayor que el de la insulina libre. Demostramos que la insulina, tanto en animales testigo como en aquellos con hiperinsulinemia, viaja unida a la porción externa del receptor (ectodominio), al cual denominamos receptor soluble de insulina, que se libera en mayor cantidad en respuesta al incremento en la insulina plasmática; en las ratas con síndrome metabólico e hiperinsulinemia, los niveles en plasma son mucho mayores que en los controles. El incremento del receptor soluble de insulina en sangre podría ser un dato temprano de síndrome metabólico.

Elevated Resting and Postprandial Digestive Proteolytic Activity in Peripheral Blood of Individuals With Type-2 Diabetes Mellitus, With Uncontrolled Cleavage of Insulin Receptors.

Objective: To examine resting and postprandial peripheral protease activity in healthy controls and individuals with type 2 diabetes mellitus (T2DM) and pre-T2DM. Methods: Individuals with T2DM or pre-T2DM and healthy controls (mean age 55.8 years) were studied before and for a span of 300 minutes following a single high-calorie McDonald's breakfast. Metalloproteases-2/-9 (MMP-2/-9), elastase, and trypsin activities were assessed in whole blood before and following the meal using a novel high-precision electrophoretic platform. Also assessed were circulating levels of inflammatory biomarkers and insulin receptor density on peripheral blood mononuclear cells (PBMCs) in relationship to protease activity. Results: Premeal MMP-2/-9 and elastase activity levels in T2DM and in pre-T2DM participants were significantly elevated as compared to controls. The T2DM group showed a significant increase in elastase activity 15 minutes after the meal; elastase activity continued to increase to the 30-minute time point (p < 0.01). In control participants, MMP-2/-9, elastase, and trypsin were significantly increased at 15 minutes after the meal (p < 0.05) and returned to premeal values within a period of approximately 30 to 60 minutes post meal. PBMCs incubated for 1 hour with plasma from T2DM and pre-T2DM participants had significantly lower levels of insulin receptor density compared to those incubated with plasma from control participants (p < 0.001). Conclusions: The results of this study suggest that individuals with T2DM and pre-T2DM have higher resting systemic protease activity than nonsymptomatic controls. A single high-calorie/high-carbohydrate meal results in further elevations of protease activity in the systemic circulation of T2DM and pre-T2DM, as well as in healthy controls. The protease activity in turn can lead to a downregulation of insulin receptor density, potentially supporting a state of insulin resistance.

Berberis aristata, Elaeis guineensis and Coffea canephora Extracts Modulate the Insulin Receptor Expression and Improve Hepatic Steatosis in NAFLD Patients: A Pilot Clinical Trial.

Non-alcoholic fatty liver disease (NAFLD) is associated with insulin resistance and diabetes. A reduction in insulin receptor (IR) expression has been reported in these patients. The aims of this study were to evaluate the effects of a mixture of plant extracts consisting of Berberis aristata, Elaeis guineensis and decaffeinated green coffee by Coffea canephora on the improvement of glycaemic profile, through the modulation of IR levels, and of hepatic steatosis in NAFLD patients. Forty-nine patients with a grade of steatosis S1-S2 were randomly allocated to the treatment with plant extracts or placebo for six months. Hepatic steatosis was evaluated using transient elastography with CAP (controlled attenuation parameter). Glucose, insulin, and IR levels were measured in serum samples. At the end of the study, patients treated with plant extracts displayed a significant reduction of serum glucose (p < 0.001), insulin levels (p < 0.01), homeostatic model assessment for insulin resistance (HOMA-IR) index (p < 0.001), and CAP value (p < 0.01) compared to placebo. Moreover, the IR expression was increased significantly in the plant extracts group compared to the placebo group (p < 0.05). The combination of plant extracts increases serum IR levels, determining amelioration of glycemic profile and improvement of hepatic steatosis in NAFLD patients.

Reduced Insulin Receptor Expression and Altered DNA Methylation in Fat Tissues and Blood of Women With GDM and Offspring.

Context: Altered expression of the insulin receptor (IR) in adipose tissue (AT) could contribute to gestational diabetes mellitus (GDM) etiopathogenesis. Transcriptional regulation via epigenetic mechanisms (e.g., DNA methylation) may play a critical role. However, the human IR promoter DNA methylation patterns and involvement in gene expression are unknown. Objective: We evaluated IR mRNA and protein expression accompanied by targeted DNA methylation analyses in AT and blood cells of women with GDM and their offspring. Design: Prospective observational study. Setting: Academic clinic and research unit. Participants: GDM-affected (n = 25) and matched control (n = 30) mother-child dyads. Main Outcome Measures: Maternal IR gene and protein expression in paired subcutaneous (SAT) and visceral adipose tissue samples (VAT). DNA methylation levels in IR promoter and intronic regions in maternal AT and blood cells of mother-offspring pairs. Results: In SAT and VAT, IR mRNA/protein expressions were significantly reduced in women with GDMs (P < 0.05). The decrease in VAT was more pronounced and independent of maternal body mass index. VAT IR protein levels were inversely associated with key maternal and neonatal anthropometric and metabolic parameters (P < 0.05). DNA methylation patterns were similar across tissues, with significant yet small size alterations between groups in mothers and offspring (P < 0.05). Conclusion: Decreased IR levels in AT may be a relevant pathogenic factor in GDM, affecting materno-fetal metabolism. Further investigation of causal factors for IR dysregulation is necessary, especially in VAT. Potential functional and/or clinical roles of altered DNA methylation also should be evaluated.

Effects of Clove and Fermented Ginger on Blood Glucose, Leptin, Insulin and Insulin Receptor Levels in High Fat DietInduced Type 2 Diabetic Rabbits.

The aimed of this research is to evaluate the effects of clove and fermented ginger supplements on blood glucose,serum insulin, insulin receptor and Leptin levels of high fat diet-induced type 2 diabetes mellitus in rabbits. Clove and gingerare spices with records of medicinal value over decades. Thirty males rabbits weighing, 1-1.5kg were used for the research.Type 2 diabetes was induced by feeding the animals with a high fat diet for a period of eight weeks. Blood glucose levelswere determined after the induction period and rabbits having 140 mg/dL and above were selected for the study. The animalswere grouped into six groups with five (n=5) rabbits in each group: Group 1 (Normoglycemic control group.) received normalfeed and distilled water ad libitum for six weeks; Group 2 (Diabetic negative control group.) received normal feed anddistilled water ad libitum for six weeks; Groups 3 (Diabetic positive control.) received cholestran 0.26g/kg and normal feedfor a period of six weeks; Group 4 and 5 (diabetic rabbits) were fed on 12.5%, clove and 12.5% fermented gingerrespectively for a period of six weeks; while Group 6 were co-fed on 12.5% clove and 12.5% fermented ginger for a periodof six weeks. Fasting blood glucose levels were determined at weekly interval during the treatment period. At the end of theexperiment, the rabbits were euthanized by cervical dislocation and blood samples were collected for the determination ofinsulin, insulin receptor and leptin levels. A significantly (P<0.05) decrease in blood glucose levels was recorded in thesupplements treated groups compared to diabetic control group. Clove supplement been most effective and sustaining inantihyperglycemic activity, also appears with a significant decreasing effect on leptin levels compared to diabetic controlgroup. A significant increase in insulin levels was also noted in the fermented ginger treated group along with higher levelsof Leptin compared as compared to control group. In conclusion the result of the study show that clove and fermented gingersupplementation possesses anti-diabetic properties and may help in the control of hyperleptinaemia in type 2 diabetes.

Gene expression of insulin receptor, insulin-like growth factor increases and insulin-like growth factor-binding protein-3 reduces with increase in prostate size in benign prostatic hyperplasia.

INTRODUCTION: Although the role of insulin in the development of benign prostatic hyperplasia (BPH) is well established, there are no studies regarding alteration in the gene expression of components of insulin-signaling pathway and their association with prostate size in BPH. Hence, the study was designed to analyze the gene and protein expression of insulin receptor and its related components in patients with BPH. MATERIALS AND METHODS: Twenty-seven BPH patients aged between 55 and 75 years were recruited in the study and prostatic tissues were obtained after transurethral resection of the prostate. Gene expression levels of Insulin receptor (IR), insulin receptor substrate (IRS), insulin-like growth factor (IGF) and insulin-like growth factor-binding protein-3 (IGFBP-3) were assessed by q-PCR. RESULTS: Insulin receptor (IR-A and B) and insulin-like growth factors (IGF-1 and IGF-2) gene expression were significantly increased and IGFBP-3 gene expression was reduced in BPH patients with larger prostate size. Also, serum insulin was significantly increased and IGFBP-3 was significantly reduced in patients with larger prostate size. CONCLUSION: Increased expression of IR-A, B and IGF-1, 2 genes and reduced IGFBP-3 gene expression was associated with larger prostate size in BPH.

Yangxin Tongmai Formula ameliorates impaired glucose tolerance in children with Graves' disease through upregulation of the insulin receptor levels.

Graves' disease (GD) is the leading cause of hyperthyroidism, and the majority of GD patients eventually develop disorders of glucose handling, which further affects their quality of life. Yangxin Tongmai formula (YTF) is modified from a famous formula of traditional Chinese medicine for the treatment of cardiovascular diseases. In this study we investigated the potential effects of YTF in the treatment of pediatric GD patients with impaired glucose tolerance. Forty pediatric GD patients and 20 healthy children were recruited for this clinical study. Based on the glucose tolerance, the GD patients were divided into two groups: 20 patients displayed impaired glucose tolerance, while the other 20 patients displayed normal glucose tolerance. YTF was orally administered for 60 days. YTF administration significantly ameliorated the abnormal glucose tolerance and insulin sensitivity in the GD patients with impaired glucose tolerance. To determine the molecular mechanisms of this observation, the number of plasma insulin receptors was determined by ELISA. Before treatment, the fasting and postprandial levels of the insulin receptor were significantly lower in patients with impaired glucose tolerance compared with those in patients with normal glucose tolerance and healthy children. After YTF treatment, both the fasting and the postprandial circulating insulin receptor levels were upregulated, and close to those in healthy children. Therefore, YTF is a potential effective treatment to enhance glucose handling in GD children with impaired glucose tolerance.

The Effect of Selenium Supplementation on Glucose Homeostasis and the Expression of Genes Related to Glucose Metabolism.

The aim of the study was to evaluate the effect of selenium supplementation on the expression of genes associated with glucose metabolism in humans, in order to explain the unclear relationship between selenium and the risk of diabetes. For gene expression analysis we used archival samples of cDNA from 76 non-diabetic subjects supplemented with selenium in the previous study. The supplementation period was six weeks and the daily dose of selenium was 200 µg (as selenium yeast). Blood for mRNA isolation was collected at four time points: before supplementation, after two and four weeks of supplementation, and after four weeks of washout. The analysis included 15 genes encoding selected proteins involved in insulin signaling and glucose metabolism. In addition, HbA1c and fasting plasma glucose were measured at three and four time points, respectively. Selenium supplementation was associated with a significantly decreased level of HbA1c but not fasting plasma glucose (FPG) and significant down-regulation of seven genes: INSR, ADIPOR1, LDHA, PDHA, PDHB, MYC, and HIF1AN. These results suggest that selenium may affect glycemic control at different levels of regulation, linked to insulin signaling, glycolysis, and pyruvate metabolism. Further research is needed to investigate mechanisms of such transcriptional regulation and its potential implication in direct metabolic effects.

Milk growth factors and expression of small intestinal growth factor receptors during the perinatal period in mice.

BACKGROUND: Growth factors (GFs) are milk bioactive components contributing to the regulation of neonatal small intestinal maturation, and their receptors on the small intestinal epithelium play essential roles in mediating the functions of GFs. There is limited data correlating milk GFs and their receptors in the neonatal small intestine during the perinatal period. METHODS: Small intestines of C57BL/6N mouse pups were collected at regular intervals during fetal life and up to postnatal day (PD) 60. Gene expression of GF receptors was determined by real-time qPCR. Milk GF concentrations up to PD21 were analyzed by enzyme-linked immunosorbent assay. RESULTS: The majority of GF receptors showed significantly greater expression in the fetus than in postnatal life, and a sharp decrease occurred from PD14 extending to PD60; solid food restriction (PD14 and PD18) did not affect this decrease. Concentrations of five detected milk GFs demonstrated that GFs and the corresponding small intestinal receptors exhibited different correlations, with only milk transforming growth factor ß1 (TGF-ß1) having a significant positive correlation with TGF-ß receptor 1 mRNA. CONCLUSION: Gene expression of small intestinal GF receptors is likely a process of neonatal intestinal maturation that is affected concurrently by milk GFs and additional endogenous factors.

Polymorphisms at Locus 4p14 of Toll-Like Receptors TLR-1 and TLR-10 Confer Susceptibility to Gastric Carcinoma in Helicobacter pylori Infection.

Helicobacter pylori (H. pylori) -induced gastric inflammation impacts the functions of leptin- and ghrelin-producing cells in the gastroduodenum. Inflammation resulting from H. pylori sensing via Toll-like receptors (TLRs) and the associated downstream signaling largely remain ambiguous. Here, we investigated the role of gut hormones, pro-inflammatory cytokines and single nucleotide polymorphisms (SNPs) associated with TLR 4p14 in H. pylori disease in 30 subjects with non-ulcer dyspepsia (NUD), 40 with peptic ulcer disease (PUD) and 15 with gastric cancer (GC) subjects positive and negative for H. pylori infection. The level of pro-inflammatory cytokines was directly proportional to the severity of gastritis, and disease status influenced the levels of gut hormones and pro-inflammatory cytokines. TLR-1 SNPs rs4833095 and TLR-10 SNPs rs10004195 and were directly associated with H. pylori disease, and were up-regulated in the presence of H. pylori in a genotype-independent manner. We concluded that TLR-1 rs4833095 and TLR10 rs10004195 confer susceptibility to development of gastroduodenal disease, especially GC in H.pylori disease.

Oat consumption reduced intestinal fat deposition and improved health span in Caenorhabditis elegans model.

In addition to their fermentable dietary fiber and the soluble ß-glucan fiber, oats have unique avenanthramides that have anti-inflammatory and antioxidant properties that reduce coronary heart disease in human clinical trials. We hypothesized that oat consumption will increase insulin sensitivity, reduce body fat, and improve health span in Caenorhabditis elegans through a mechanism involving the daf-2 gene, which codes for the insulin/insulin-like growth factor-1-like receptor, and that hyperglycemia will attenuate these changes. Caenorhabditis elegans wild type (N2) and the null strains sir-2.1, daf-16, and daf-16/daf-2 were fed Escherichia coli (OP50) and oat flakes (0.5%, 1.0%, or 3%) with and without 2% glucose. Oat feeding decreased intestinal fat deposition in N2, daf-16, or daf-16/daf-2 strains (P < .05); and glucose did not affect intestinal fat deposition response. The N2, daf-16, or sir-2.1 mutant increased the pharyngeal pumping rate (P < .05), a surrogate marker of life span, following oat consumption. Oat consumption increased ckr-1, gcy-8, cpt-1, and cpt-2 mRNA expression in both the N2 and the sir-2.1 mutant, with significantly higher expression in sir-2.1 than in N2 (P < .01). Additional glucose further increased expression 1.5-fold of the 4 genes in N2 (P < .01), decreased the expression of all except cpt-1 in the daf-16 mutant, and reduced mRNA expression of the 4 genes in the daf-16/daf-2 mutant (P < .01). These data suggest that oat consumption reduced fat storage and increased ckr-1, gcy-8, cpt-1, or cpt-2 through the sir-2.1 genetic pathway. Oat consumption may be a beneficial dietary intervention for reducing fat accumulation, augmenting health span, and improving hyperglycemia-impaired lipid metabolism.

Impaired insulin signaling pathway in ovarian follicles of cows with cystic ovarian disease.

Cystic ovarian disease (COD) is an important cause of infertility in dairy cattle. Follicular cell steroidogenesis and proliferation in ovulatory follicles is stimulated by hormones such as insulin and its necessary post-receptor response. The aim of this study was to determine the expression of insulin receptor (IR), IR substrate-1 (IRS1) and phosphatidylinositol 3-kinase (PI3K), key intermediates in the insulin pathway, in control cows and cows with spontaneous COD and ACTH-induced COD. IR and IRS1 mRNA levels were greater in granulosa cells and lower in follicular cysts than in control tertiary follicles. PI3K mRNA levels were similar in all follicles evaluated, whereas the expression of IR, IRS1 and PI3K was similar in theca cells. Protein expression of IR was higher in control tertiary follicles than in the same structures in animals with COD and with cysts. IRS1 and PI3K protein expression showed the same pattern in tertiary and cystic follicles. However, the protein expression of subunit alpha p85 of PI3K was greater in theca cells from tertiary follicles than in cystic follicles. These results provide new insights into the insulin response in cows with COD. The lower gene and protein expressions of some insulin downstream effectors at an early stage of the signaling pathway could negatively influence the functionality of ovaries and contribute to follicle persistence.

Soluble insulin receptor as a source of insulin resistance and cognitive impairment in HIV-seropositive women.

Insulin resistance occurs in HIV-infected individuals and is associated with HIV-associated neurocognitive disorders (HAND). However, the mechanisms involved are not well understood. Previously, we showed a correlation between soluble insulin receptor (sIR) and HAND. Here, we investigated if binding of free insulin to sIR and soluble insulin-like growth factor-1 receptor (sIGF1-R) levels are associated with sIR in HAND. Thirty-four (34) HIV-seropositive women stratified by cognitive status and five HIV-seronegative women were evaluated. In a subgroup of 20 HIV positive and 5 donors, binding of plasma insulin to sIR was determined by ELISA assay of residual insulin levels in plasma immuno-depleted with anti-IR-monoclonal antibody-Sepharose beads. sIR and sIGF1-R levels were determined by ELISA. Nonparametric statistics were used. Higher percentages of insulin bound to sIR significantly correlated with sIR levels and were associated with HAND status. Higher levels of plasma sIGF1-R had a positive correlation with sIR levels (p = 0.011) and were associated with HAND (p = 0.006). No correlations were observed with age, viral-immune profile, antiretroviral therapy, or TNF. This study suggests that changes in sIGF1-R levels and insulin binding to sIR may contribute to HAND.

Development of in vitro model of insulin receptor cleavage induced by high glucose in HepG2 cells.

Soluble insulin receptor (sIR), the ectodomain of IR, has been detected in human plasma, and its concentration parallels that of blood glucose in patients with diabetes. IR has a pivotal role in glucose homeostasis and diabetes development; therefore, cleavage of IR promoted by hyperglycemia is involved in insulin resistance and glucose toxicity. To elucidate the physiology of sIR, we developed an in vitro model mimicking the changes in sIR levels in plasma from patients with diabetes. Among four human cell lines that expressed IR, spontaneous cleavage of IR occurred only in HepG2 cells. The molecular characteristics of sIR derived from HepG2 cells were similar to those of sIR detected in human plasma. The concentration of sIR in the medium did not differ between basal and high-glucose conditions in the initial 24-h period, but increasing the duration of pre-stimulation (>48 h) led to a significant increase in sIR levels in cells exposed to high glucose. Additionally, glucose-dependent increment of sIR was reversible in this model. These results are consistent with the observation of plasma sIR in patients with diabetes. Using this model, O-linked N-acetylglucosamine modification was determined to be involved in high-glucose-induced IR cleavage. A calcium-dependent protease was shown to cleave IR extracellularly. These findings show that this in vitro model could be useful for determining the molecular mechanism underlying IR cleavage.

Influence of breastfeeding on blood-cell transcript-based biomarkers of health in children.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: The expression of specific genes in peripheral blood cells (PBCs) may be used as biomarkers of the metabolic status. High levels of expression of CPT1A, SLC27A2, INSR, LEPR, FASN and PPARα in PBCs are indicative of a lower risk for the insulin resistant or dyslipidaemic state associated with obesity in children. Breastfeeding seems to confer protective effects against obesity and its related metabolic problems. WHAT THIS STUDY ADDS: Children who had been breastfed showed higher expression levels of SLC27A2, FASN, PPARα and INSR in PBCs compared with formula-fed subjects. The relationship of the PBC transcript levels of SLC27A2, INSR, FASN and PPARα with insulin resistance and dyslipidaemia may be dependent on the type of infant feeding (breast vs. formula). The transcript levels of the mentioned biomarkers could be useful to distinguish the formula-fed children who are at higher risk of metabolic alterations. BACKGROUND: Blood-cell transcripts have showed to be good biomarkers of metabolic alterations and their use in early detection and prevention of future disorders is promising. OBJECTIVE: This study aimed to examine the relation between previously proposed transcriptional biomarkers of metabolic health (SLC27A2, CPT1A, FASN, PPARα, INSR, LEPR) in peripheral blood cells and the type of infant feeding in a subset of children from the IDEFICS (Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants) cohort. SUBJECTS: A total of 237 children aged 2-9 years from eight European countries were studied. RESULTS: Breastfed children showed higher expression levels of SLC27A2, FASN, PPARα and INSR, and lower risk of being overweight and of having high plasma triglyceride levels vs. formula-fed children. Besides, overweight formula-fed children presented higher HOMA-index than overweight breastfed children (1.90 vs. 1.62); however, this negative effect was absent in formula-fed children with high expression of SLC27A2. Moreover, formula-fed children with low expression of SLC27A2, FASN, PPARα and INSR presented higher triglyceride levels than subjects with high expression of these genes (77.7 mg dL(-1) vs. 44.8 mg dL(-1) ). This difference was absent in breastfed children. CONCLUSIONS: Protective effects of breastfeeding are reflected in higher expression levels of SLC27A2, FASN, PPARα and INSR in blood cells. These biomarkers may also serve to discriminate the formula-fed children that are at higher risk of metabolic alterations.

The serine protease granzyme B as an inflammatory marker, in relation to the insulin receptor cleavage in human obesity and type 2 diabetes mellitus.

Chronic inflammation and insulin resistance form hallmarks of type 2 diabetes mellitus (T2DM). An increased circulating level of the serine protease granzyme B (GzmB) is observed during prolonged inflammation and is implicated in the pathogenesis of several chronic inflammatory diseases. Moreover, insulin receptor cleavage by unknown proteases, yielding elevated levels of insulin receptor α-subunit (IRα), was observed in T2DM and was proposed as a new mechanism of insulin resistance. Therefore, a possible association between GzmB and IRα is suggested. Accordingly, this study was set to explore whether GzmB and IRα levels are altered in T2DM patients with the impact of obesity. Furthermore, we aimed to identify if GzmB contributes towards inflammation and insulin resistance through its suggested extracellular activities. All subjects were assessed for anthropometric and metabolic parameters related to obesity and T2DM. In addition, fasting plasma insulin, GzmB, interleukin-1ß (IL-1ß), and IRα levels were estimated by enzyme linked immunosorbent assay. Levels of GzmB and IRα were found to be significantly elevated in T2DM patients compared to nondiabetic subjects. In addition, GzmB levels were positively correlated with measures of obesity and insulin resistance, IL-1ß, IRα, and other metabolic parameters. While multiple linear regression analysis revealed that both T2DM and central obesity were predicting factors for GzmB, our findings reveal a possible role of GzmB in T2DM.

Pancreatic digestive enzyme blockade in the small intestine prevents insulin resistance in hemorrhagic shock.

Hemorrhagic shock is associated with metabolic defects, including hyperglycemia and insulin resistance, but the mechanisms are unknown. We recently demonstrated that reduction of the extracellular domain of the insulin receptor by degrading proteases may lead to a reduced ability to maintain normal plasma glucose values. In shock, transfer of digestive enzymes from the lumen of the intestine into the systemic circulation after breakdown of the intestinal mucosal barrier causes inflammation and organ dysfunction. Suppression of the digestive enzymes in the lumen of the intestine with protease inhibitors is effective in reducing the level of the inflammatory reactions. To determine the degree to which blockade of digestive enzymes affects insulin resistance in shock, rats were exposed to acute hemorrhagic shock (mean arterial pressure of 30 mmHg for 2 h) at which time all shed blood volume was returned. Digestive proteases in the intestine were blocked with a serine protease inhibitor (tranexamic acid in polyethylene glycol and physiological electrolyte solution), and the density of the insulin receptor was measured with immunohistochemistry in the mesentery microcirculation. The untreated rat without enzyme blockade had significantly attenuated levels of insulin receptor density as compared with control and treated rats. Blockade of the digestive proteases after 60 min of hypotension in the lumen of the small intestine led to a lesser decrease in insulin receptor density compared with controls without protease blockade. Glucose tolerance test indicates a significant increase in plasma glucose levels 2 h after hemorrhagic shock, which are reduced to control values in the presence of protease inhibition in the lumen of the intestine. The transient reduction of the plasma glucose levels after an insulin bolus is significantly attenuated after shock but is restored when digestive enzymes in the lumen of the intestine are blocked. These results suggest that in hemorrhagic shock elevated microvascular extracellular digestive enzyme activity causes insulin receptor dysfunction, hyperglycemia, and reduced ability to regulate blood glucose values.

Soluble and cell-associated insulin receptor dysfunction correlates with severity of HAND in HIV-infected women.

BACKGROUND: Blood sugar metabolism abnormalities have been identified in HIV-infected individuals and associated with HIV-associated neurocognitive disorders (HAND). These abnormalities may occur as a result of chronic HIV infection, long-term use of combined antiretroviral treatment (CART), aging, genetic predisposition, or a combination of these factors, and may increase morbidity and mortality in this population. OBJECTIVE: To determine if changes in soluble and cell-associated insulin receptor (IR) levels, IR substrate-1 (IRS-1) levels, and IRS-1 tyrosine phosphorylation are associated with the presence and severity of HAND in a cohort of HIV-seropositive women. METHODS AND RESULTS: This is a retrospective cross-sectional study using patient database information and stored samples from 34 HIV-seropositive women and 10 controls without history of diabetes from the Hispanic-Latino Longitudinal Cohort of Women. Soluble IR subunits [sIR, ectodomain (α) and full-length or intact (αß)] were assayed in plasma and CSF samples by ELISA. Membrane IR levels, IRS-1 levels, and IRS-1 tyrosine phosphorylation were analyzed in CSF white cell pellets (WCP) using flow cytometry. HIV-seropositive women had significantly increased levels of intact or full-length sIR in plasma (p<0.001) and CSF (p<0.005) relative to controls. Stratified by HAND, increased levels of full-length sIR in plasma were associated with the presence (p<0.001) and severity (p<0.005) of HAND. A significant decrease in IRS-1 tyrosine-phosphorylation in the WCP was also associated with the presence (p<0.02) and severity (p<0.02) of HAND. CONCLUSIONS: This study provides evidence that IR secretion is increased in HIV-seropositive women, and increased IR secretion is associated with cognitive impairment in these women. Thus, IR dysfunction may have a role in the progression of HAND and could represent a biomarker for the presence and severity of HAND.