Healthy aging: the INTECMAN project.

Aging is associated not only with the reduction of psychophysical and sensory capacities but also with different types of neurodegenerative disorders up to dementia manifestations. Aging in health and self-sufficiency is strictly dependent on the prevention and correction of factors that may determine reduction of psychophysical capacities (e.g., cardiovascular, locomotor and neurodegenerative ones). To reach this goal, due to the dynamics of social and family changes and to the aging of the population, health professionals can be supported by technologies which provide noninvasive monitoring of physiologic parameters and rely on telemedicine, both instruments of support and care for better aging in the home setting. The authors, starting from the initial idea of a personalized monitoring of different psychophysical variables, defined a pilot study to assess the role of a 12-month individually tailored lifestyle counseling on parameters of mild cognitive impairment in a group of elderly subjects. Data derived from the applied approach appeared promising and may open the road to the possible implementation of individual counseling, based on multiparametric non-obtrusive technologies which take into consideration both psychological and physical aspects, to be followed in the home environment.

Biomonitoring of Bis(2-ethylhexyl)phthalate (DEHP) in Italian children and adolescents: Data from LIFE PERSUADED project.

The Bis(2-ethylhexyl)phthalate (DEHP), a widespread plasticizer, is considered an endocrine disrupting chemical with main toxicological effects on reproductive and metabolic systems. Human biomonitoring (HBM) studies are promoted to evaluate the background exposure levels. In the frame of LIFE PERSUADED project, the HBM study measured DEHP main metabolites (mono-(2-ethylhexyl) phthalate, MEHP; 2-ethyl-5-hydroxy-hexylphthalate, MEHHP; 2-ethyl-5-oxo-hexylphthalate, MEOHP) in Italian children and adolescent (4-14 years old) according to geographical macro-areas and areas, age and sex. Children from the South and the Centre of Italy showed higher median levels of DEHP, as a sum of its metabolites (48.14 and 47.80 µg/L), than those from the North (39.47 µg/L; p = 0.0090 and 0.0004, respectively). Considering the total population, boys are more exposed than girls (only as urinary volume), and children aged 4-6 years have higher median levels than those 7-10 and 11-14 years old. The derived reference values (RV95) for DEHP in children is 168 µg/L. The relative metabolic rates of DEHP, the background levels and, thus, the RV95, vary with the geographical area, age and sex, indicating that all these parameters should be considered in the risk assessment.

Cardiometabolic risk and subclinical vascular damage assessment in idiopathic inflammatory myopathies: a challenge for the clinician.

OBJECTIVES: A high prevalence of cardiovascular disease (CVD), not fully explained by the prevalence of traditional risk factors only, is reported in patients with idiopathic inflammatory myopathies (IIMs). Thus, we investigated if novel markers of CVD risk, like carotid diameter and advanced glycated end products, can better predict increased CVD risk in IIM patients. METHODS: We studied 43 consecutive patients diagnosed with IIM. All the patients underwent a clinical and laboratory evaluation of cardiovascular risk factors and characterisation of myositis disease activity. Non-invasive instrumental examinations performed included the measurement of carotid parameters (intima-media thickness, IMT and mean arterial diameter, mAD) by ultrasonic techniques, advanced glycation end-product accumulation in the skin by autofluorescence (AF) and body composition by bioelectrical impedance analysis. The parameters were compared to those measured in 29 controls, with similar mean age, BMI, blood pressure and smoking habits. RESULTS: IIM patients showed normal carotid IMT and distensibility, but higher carotid mAD (p=0.012), higher skin AF (p<0.001), lower fat free mass (p=0.036) and increased waist circumference compared to controls. A significant correlation was observed among AF and mAD (rho=0.317 p<0.05), carotid distension (rho=0.391 p=0.036) and IMT (rho=0.627 p<0.001). CONCLUSIONS: Abnormalities of the studied parameters suggest a higher risk of CV disease in IIM patients independent of disease activity. In this population, a thorough assessment of CV risk is recommended also in absence of overt CV disease during the clinical evaluation.

The LIFE PERSUADED project approach on phthalates and bisphenol A biomonitoring in Italian mother-child pairs linking exposure and juvenile diseases.

Phthalates and bisphenol A (BPA), plasticizers used in several products of daily life, are considered as endocrine disrupters, therefore children exposure is particularly relevant. The LIFE PERSUADED project aims to define the following: (a) the evaluation of internal levels of DEHP's metabolites and BPA in Italian children and their mothers, (b) the association of the exposure with puberty development and obesity diseases, and (c) the effects of exposure in juvenile in vivo model. The cross-sectional study has involved 2160 mother-child pairs, including males and females, children and adolescents, from urban and rural areas of North, Center, and South Italy. A structured questionnaire and a food diary are designed to evaluate the association between lifestyle variables potentially related to DEHP/BPA exposure and internal levels, through univariate and multivariate analyses. Two pilot case-control studies are carried out on idiopathic premature thelarche and precocious puberty (30 girls each group, aged 2-7 years) and idiopathic obesity (30 boys and 30 girls, aged 6-10 years), matched to healthy controls. BPA and DEHP's metabolites are analyzed in urine samples from all recruited subjects. Clinical and toxicological biomarkers are evaluated in serum of case-control subjects. Moreover, the toxicity study is carried out in a juvenile rodent model exposed to mixtures of BPA and DEHP at dose levels recorded in children population. The scientific results of LIFE PERSUADED will contribute to risk assessment of BPA and DEHP.

The antidepressant fluoxetine acts on energy balance and leptin sensitivity via BDNF.

Leptin and Brain Derived Neurotrophic Factor (BDNF) pathways are critical players in body weight homeostasis. Noninvasive treatments like environmental stimulation are able to increase response to leptin and induce BDNF expression in the brain. Emerging evidences point to the antidepressant selective serotonin reuptake inhibitor Fluoxetine (FLX) as a drug with effects similar to environmental stimulation. FLX is known to impact on body weight, with mechanisms yet to be elucidated. We herein asked whether FLX affects energy balance, the leptin system and BDNF function. Adult lean male mice chronically treated with FLX showed reduced weight gain, higher energy expenditure, increased sensitivity to acute leptin, increased hypothalamic BDNF expression, associated to changes in white adipose tissue expression typical of "brownization". In the Ntrk2tm1Ddg/J model, carrying a mutation in the BDNF receptor Tyrosine kinase B (TrkB), these effects are partially or totally reversed. Wild type obese mice treated with FLX showed reduced weight gain, increased energy output, and differently from untreated obese mice, a preserved acute response to leptin in terms of activation of the intracellular leptin transducer STAT3. In conclusion, FLX impacts on energy balance and induces leptin sensitivity and an intact TrkB function is required for these effects to take place.

Altered amino acid concentrations in NAFLD: Impact of obesity and insulin resistance.

Plasma concentrations of amino acids (AAs), in particular, branched chain AAs (BCAAs), are often found increased in nonalcoholic fatty liver disease (NAFLD); however, if this is due to increased muscular protein catabolism, obesity, and/or increased insulin resistance (IR) or impaired tissue metabolism is unknown. Thus, we evaluated a) if subjects with NAFLD without obesity (NAFLD-NO) compared to those with obesity (NAFLD-Ob) display altered plasma AAs compared to controls (CTs); and b) if AA concentrations are associated with IR and liver histology. Glutamic acid, serine, and glycine concentrations are known to be altered in NAFLD. Because these AAs are involved in glutathione synthesis, we hypothesized they might be related to the severity of NAFLD. We therefore measured the AA profile of 44 subjects with NAFLD without diabetes and who had a liver biopsy (29 NAFLD-NO and 15 NAFLD-Ob) and 20 CTs without obesity, by gas chromatography-mass spectrometry, homeostasis model assessment of insulin resistance, hepatic IR (Hep-IR; Hep-IR = endogenous glucose production × insulin), and the new glutamate-serine-glycine (GSG) index (glutamate/[serine + glycine]) and tested for an association with liver histology. Most AAs were increased only in NAFLD-Ob subjects. Only alanine, glutamate, isoleucine, and valine, but not leucine, were increased in NAFLD-NO subjects compared to CTs. Glutamate, tyrosine, and the GSG-index were correlated with Hep-IR. The GSG-index correlated with liver enzymes, in particular, gamma-glutamyltransferase (R = 0.70), independent of body mass index. Ballooning and/or inflammation at liver biopsy were associated with increased plasma BCAAs and aromatic AAs and were mildly associated with the GSG-index, while only the new GSG-index was able to discriminate fibrosis F3-4 from F0-2 in this cohort. CONCLUSION: Increased plasma AA concentrations were observed mainly in subjects with obesity and NAFLD, likely as a consequence of increased IR and protein catabolism. The GSG-index is a possible marker of severity of liver disease independent of body mass index. (Hepatology 2018;67:145-158).

Author Correction: Lack of NLRP3-inflammasome leads to gut-liver axis derangement, gut dysbiosis and a worsened phenotype in a mouse model of NAFLD.

A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.

Lack of NLRP3-inflammasome leads to gut-liver axis derangement, gut dysbiosis and a worsened phenotype in a mouse model of NAFLD.

Non-Alcoholic Fatty Liver Disease (NAFLD) represents the most common form of chronic liver injury and can progress to cirrhosis and hepatocellular carcinoma. A "multi-hit" theory, involving high fat diet and signals from the gut-liver axis, has been hypothesized. The role of the NLRP3-inflammasome, which senses dangerous signals, is controversial. Nlrp3-/- and wild-type mice were fed a Western-lifestyle diet with fructose in drinking water (HFHC) or a chow diet. Nlrp3-/--HFHC showed higher hepatic expression of PPAR γ2 (that regulates lipid uptake and storage) and triglyceride content, histological score of liver injury and greater adipose tissue inflammation. In Nlrp3-/--HFHC, dysregulation of gut immune response with impaired antimicrobial peptides expression, increased intestinal permeability and the occurrence of a dysbiotic microbiota led to bacterial translocation, associated with higher hepatic expression of TLR4 (an LPS receptor) and TLR9 (a receptor for double-stranded bacterial DNA). After antibiotic treatment, gram-negative species and bacterial translocation were reduced, and adverse effects restored both in liver and adipose tissue. In conclusion, the combination of a Western-lifestyle diet with innate immune dysfunction leads to NAFLD progression, mediated at least in part by dysbiosis and bacterial translocation, thus identifying new specific targets for NAFLD therapy.

Gut to brain interaction in Autism Spectrum Disorders: a randomized controlled trial on the role of probiotics on clinical, biochemical and neurophysiological parameters.

BACKGROUND: A high prevalence of a variety of gastrointestinal (GI) symptoms is frequently reported in patients with Autism Spectrum Disorders (ASD). The GI disturbances in ASD might be linked to gut dysbiosis representing the observable phenotype of a "gut-brain axis" disruption. The exploitation of strategies which can restore normal gut microbiota and reduce the gut production and absorption of toxins, such as probiotics addition/supplementation in a diet, may represent a non-pharmacological option in the treatment of GI disturbances in ASD. The aim of this randomized controlled trial is to determine the effects of supplementation with a probiotic mixture (Vivomixx®) in ASD children not only on specific GI symptoms, but also on the core deficits of the disorder, on cognitive and language development, and on brain function and connectivity. An ancillary aim is to evaluate possible effects of probiotic supplementation on urinary concentrations of phthalates (chemical pollutants) which have been previously linked to ASD. METHODS: A group of 100 preschoolers with ASD will be classified as belonging to a GI group or to a Non-GI (NGI) group on the basis of a symptom severity index specific to GI disorders. In order to obtain four arms, subjects belonging to the two groups (GI and NGI) will be blind randomized 1:1 to regular diet with probiotics or with placebo for 6 months. All participants will be assessed at baseline, after three months and after six months from baseline in order to evaluate the possible changes in: (1) GI symptoms; (2) autism symptoms severity; (3) affective and behavioral comorbid symptoms; (4) plasmatic, urinary and fecal biomarkers related to abnormal intestinal function; (5) neurophysiological patterns. DISCUSSION: The effects of treatments with probiotics on children with ASD need to be evaluated through rigorous controlled trials. Examining the impact of probiotics not only on clinical but also on neurophysiological patterns, the current trial sets out to provide new insights into the gut-brain connection in ASD patients. Moreover, results could add information to the relationship between phthalates levels, clinical features and neurophysiological patterns in ASD. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02708901 . Retrospectively registered: March 4, 2016.

Peripheral insulin resistance predicts liver damage in nondiabetic subjects with nonalcoholic fatty liver disease.

UNLABELLED: Surrogate indexes of insulin resistance and insulin sensitivity are widely used in nonalcoholic fatty liver disease (NAFLD), although they have never been validated in this population. We aimed to validate the available indexes in NAFLD subjects and to test their ability to predict liver damage also in comparison with the NAFLD fibrosis score. Surrogate indexes were validated by the tracer technique (6,6-D2 -glucose and U-(13) C-glucose) in the basal state and during an oral glucose tolerance test. The best-performing indexes were used in an independent cohort of 145 nondiabetic NAFLD subjects to identify liver damage (fibrosis and nonalcoholic steatohepatitis). In the validation NAFLD cohort, homeostasis model assessment of insulin resistance, insulin to glucose ratio, and insulin sensitivity index Stumvoll had the best association with hepatic insulin resistance, while peripheral insulin sensitivity was most significantly related to oral glucose insulin sensitivity index (OGIS), insulin sensitivity index Stumvoll, and metabolic clearance rate estimation without demographic parameters. In the independent cohort, only oral glucose tolerance test-derived indexes were associated with liver damage and OGIS was the best predictor of significant (≥F2) fibrosis (odds ratio = 0.76, 95% confidence interval 0.61-0.96, P = 0.0233) and of nonalcoholic steatohepatitis (odds ratio = 0.75, 95% confidence interval 0.63-0.90, P = 0.0021). Both OGIS and NAFLD fibrosis score identified advanced (F3/F4) fibrosis, but OGIS predicted it better than NAFLD fibrosis score (odds ratio = 0.57, 95% confidence interval 0.45-0.72, P < 0.001) and was also able to discriminate F2 from F3/F4 (P < 0.003). CONCLUSION: OGIS is associated with peripheral insulin sensitivity in NAFLD and inversely associated with an increased risk of significant/advanced liver damage in nondiabetic subjects with NAFLD.

Non-alcoholic fatty liver disease (NAFLD) and its connection with insulin resistance, dyslipidemia, atherosclerosis and coronary heart disease.

Non-alcoholic fatty liver disease is marked by hepatic fat accumulation not due to alcohol abuse. Several studies have demonstrated that NAFLD is associated with insulin resistance leading to a resistance in the antilipolytic effect of insulin in the adipose tissue with an increase of free fatty acids (FFAs). The increase of FFAs induces mitochondrial dysfunction and development of lipotoxicity. Moreover, in subjects with NAFLD, ectopic fat also accumulates as cardiac and pancreatic fat. In this review we analyzed the mechanisms that relate NAFLD with metabolic syndrome and dyslipidemia and its association with the development and progression of cardiovascular disease.

Effects of adding exercise to a 16-week very low-calorie diet in obese, insulin-dependent type 2 diabetes mellitus patients.

CONTEXT: Reduction of 50% excess body weight, using a very low-calorie diet (VLCD; 450 kcal/d) improves insulin sensitivity in obese type 2 diabetes mellitus patients. OBJECTIVE: The objective of the study was to evaluate whether adding exercise to the VLCD has additional benefits. DESIGN: This was a randomized intervention study. SETTING: The study was conducted at a clinical research center in an academic medical center. SUBJECTS: Twenty-seven obese [body mass index 37.2 ± 0.9 kg/m(2) (mean ± sem)] insulin-treated type 2 diabetes mellitus patients. INTERVENTION: Patients followed a 16-wk VLCD. Thirteen of them simultaneously participated in an exercise program (E) consisting of 1-h, in-hospital training and four 30-min training sessions on a cycloergometer weekly. OUTCOME MEASURES: Insulin resistance was measured by a hyperinsulinemic euglycemic clamp. Insulin signaling, mitochondrial DNA (mtDNA) content, and intramyocellular lipid content was measured in skeletal muscle biopsies. RESULTS: Baseline characteristics were identical in both groups. Substantial weight loss occurred (-23.7 ± 1.7 kg VLCD-only vs. -27.2 ± 1.9 kg VLCD+E, P = NS within groups). The exercise group lost more fat mass. Insulin-stimulated glucose disposal increased similarly in both study groups [15.0 ± 0.9 to 39.2 ± 4.7 µmol/min(-1) · kg lean body mass (LBM(-1)) VLCD-only vs. 17.0 ± 1.0 to 37.5 ± 3.5 µmol/min(-1) · kg LBM(-1) in VLCD+E], as did phosphorylation of the phosphatidylinositol 3-kinase-protein kinase B/AKT insulin signaling pathway. In contrast, skeletal muscle mtDNA content increased only in the VLCD+E group (1211 ± 185 to 2288 ± 358, arbitrary units, P = 0.016 vs. 1397 ± 240 to 1196 ± 179, P = NS, VLCD-only group). Maximum aerobic capacity also only increased significantly in the VLCD+E group (+6.6 ± 1.7 ml/min(-1) · kg LBM(-1) vs. +0.7 ± 1.5 ml/min(-1) · kg LBM(-1) VLCD-only, P = 0.017). CONCLUSION: Addition of exercise to a 16-wk VLCD induces more fat loss. Exercise augments maximum aerobic capacity and skeletal muscle mtDNA content. These changes are, however, not reflected in a higher insulin-stimulated glucose disposal rate.

Glucokinase links Krüppel-like factor 6 to the regulation of hepatic insulin sensitivity in nonalcoholic fatty liver disease.

UNLABELLED: The polymorphism, KLF6-IVS1-27A, in the Krüppel-like factor 6 (KLF6) transcription factor gene enhances its splicing into antagonistic isoforms and is associated with delayed histological progression of nonalcoholic fatty liver disease (NAFLD). To explore a potential role for KLF6 in the development of insulin resistance, central to NAFLD pathogenesis, we genotyped KLF6-IVS1-27 in healthy subjects and assayed fasting plasma glucose (FPG) and insulin sensitivities. Furthermore, we quantified messenger RNA (mRNA) expression of KLF6 and glucokinase (GCK), as an important mediator of insulin sensitivity, in human livers and in liver tissues derived from a murine Klf6 knockdown model (DeltaKlf6). Klf6 overexpression studies in a mouse hepatocyte line were utilized to mechanistically link KLF6 with Gck promoter activity. KLF6-IVS1-27Gwt (i.e., less KLF6 splicing) was associated with stepwise increases in FPG and insulin and reduced hepatic insulin sensitivity. KLF6 binds to the liver-specific Gck promoter and activates a GCK promoter-reporter, identifying GCK as a KLF6 direct transcriptional target. Accordingly, in DeltaKlf6 hepatocytes Gck expression was reduced and stable transfection of Klf6 led to up-regulation of Gck. GCK and KLF6 mRNAs correlate directly in human NAFLD tissues and immunohistochemistry studies confirm falling levels of both KLF6 and GCK in fat-laden hepatocytes. In contrast to full-length KLF6, splice variant KLF6-SV1 increases in NAFLD hepatocytes and inversely correlates with glucokinase regulatory protein, which negatively regulates GCK activity. CONCLUSION: KLF6 regulation of GCK contributes to the development of hepatic insulin resistance. The KLF6-IVS1-27A polymorphism, which generates more KLF6-SV1, combats this, lowering hepatic insulin resistance and blood glucose.

Decreased whole body lipolysis as a mechanism of the lipid-lowering effect of pioglitazone in type 2 diabetic patients.

Pioglitazone has been shown to reduce fasting triglyceride levels. The mechanisms of this effect have not been fully elucidated, but decreased lipolysis may contribute to blunt the hypertriglyceridemic response to a meal. To test this hypothesis, we studied 27 type 2 diabetes mellitus (T2DM) patients and 7 sex-, age-, and body mass index-matched nondiabetic controls. Patients were randomized to pioglitazone (45 mg/day) or placebo for 16 wk. Whole body lipolysis was measured [as the [(2)H(5)]glycerol rate of appearance (R(a))] in the fasting state and for 6 h following a mixed meal. Compared with controls, T2DM had higher postprandial profiles of plasma triglycerides, free fatty acid (FFA), and beta-hydroxybutyrate, and a decreased suppression of glycerol R(a) (P < 0.04) despite higher insulin levels [268 (156) vs. 190 (123) pmol/l, median (interquartile range)]. Following pioglitazone, triglycerides and FFA were reduced (P = 0.05 and P < 0.04, respectively), and glycerol R(a) was more suppressed [-40 (137) vs. +7 (202) mumol/min of placebo, P < 0.05] despite a greater fall in insulin [-85 (176) vs. -20 (58) pmol/l, P = 0.05]. We conclude that, in well-controlled T2DM patients, whole body lipolysis is insulin resistant, and pioglitazone improves the insulin sensitivity of lipolysis.

Relationship between hepatic/visceral fat and hepatic insulin resistance in nondiabetic and type 2 diabetic subjects.

BACKGROUND AND AIMS: Abdominal fat accumulation (visceral/hepatic) has been associated with hepatic insulin resistance (IR) in obesity and type 2 diabetes (T2DM). We examined the relationship between visceral/hepatic fat accumulation and hepatic IR/accelerated gluconeogenesis (GNG). METHODS: In 14 normal glucose tolerant (NGT) (body mass index [BMI] = 25 +/- 1 kg/m(2)) and 43 T2DM (24 nonobese, BMI = 26 +/- 1; 19 obese, BMI = 32 +/- 1 kg/m(2)) subjects, we measured endogenous (hepatic) glucose production (3-(3)H-glucose) and GNG ((2)H(2)O) in the basal state and during 240 pmol/m(2)/min euglycemic-hyperinsulinemic clamp, and liver (LF) subcutaneous (SAT)/visceral (VAT) fat content by magnetic resonance spectroscopy/magnetic resonance imaging. RESULTS: LF was increased in lean T2DM compared with lean NGT (18% +/- 3% vs 9% +/- 2%, P < .03), but was similar in lean T2DM and obese T2DM (18% +/- 3% vs 22% +/- 3%; P = NS). Both VAT and SAT increased progressively from lean NGT to lean T2DM to obese T2DM. T2DM had increased basal endogenous glucose production (EGP) (NGT, 15.1 +/- 0.5; lean T2DM, 16.3 +/- 0.4; obese T2DM, 17.2 +/- 0.6 micromol/min/kg(ffm); P = .02) and basal GNG flux (NGT, 8.6 +/- 0.4; lean T2DM, 9.6 +/- 0.4; obese T2DM, 11.1 +/- 0.6 micromol/min/kg(ffm); P = .02). Basal hepatic IR index (EGP x fasting plasma insulin) was increased in T2DM (NGT, 816 +/- 54; lean T2DM, 1252 +/- 164; obese T2DM, 1810 +/- 210; P = .007). In T2DM, after accounting for age, sex, and BMI, both LF and VAT, but not SAT, were correlated significantly (P < .05) with basal hepatic IR and residual EGP during insulin clamp. Basal percentage of GNG and GNG flux were correlated positively with VAT (P < .05), but not with LF. LF, but not VAT, was correlated with fasting insulin, insulin-stimulated glucose disposal, and impaired FFA suppression by insulin (all P < .05). CONCLUSIONS: Abdominal adiposity significantly affects both lipid (FFA) and glucose metabolism. Excess VAT primarily increases GNG flux. Both VAT and LF are associated with hepatic IR.

Quantification of liver glucose metabolism by positron emission tomography: validation study in pigs.

BACKGROUND & AIMS: The liver is inaccessible to organ balance measurements in humans. To validate [(18)F]fluorodeoxyglucose ([(18)F]FDG) positron emission tomography (PET) in the quantification of hepatic glucose uptake (HGU), we determined [(18)F]FDG modeling parameters, lumped constant (LC), and input functions (single arterial versus dual). METHODS: Anesthetized pigs were studied during fasting (n = 6), physiologic (n = 4), and supraphysiologic (n = 4) hyperinsulinemia. PET was performed with C(15)O (blood pool) and [(18)F]FDG (glucose uptake). 6,6-Deuterated glucose ([(2)H]G) was coinjected with [(18)F]FDG and blood collected from the carotid artery and portal and hepatic veins to compute LC as ratio between tracers fractional extraction. HGU was estimated from PET images and ex vivo from high-performance liquid chromatography measurements of liver [(18)F]FDG versus [(18)F]FDG-6-phosphate and [(18)F]-glycogen. Endogenous glucose production was measured with [(2)H]G and hepatic blood flow by flowmeters. RESULTS: HGU was increased in hyperinsulinemia versus fasting (P < .05). Fractional extraction of [(18)F]FDG and [(2)H]G was similar (not significant), intercorrelated (r = 0.98, P < .0001), and equally higher during hyperinsulinemia than fasting (P 0.95, P < .0001), with a modest underestimation of HGU by the former. CONCLUSIONS: [(18)F]FDG-PET-derived parameters provide accurate quantification of HGU and estimates of liver perfusion and glucose production. In the liver, LC of [(18)F]FDG is nearly unitary. Using a single arterial input introduces only a small error in estimation of HGU.

The effect of pioglitazone on the liver: role of adiponectin.

OBJECTIVE: Diabetic hyperglycemia results from insulin resistance of peripheral tissues and glucose overproduction due to increased gluconeogenesis (GNG). Thiazolidinediones (TZDs) improve peripheral insulin sensitivity, but the effect on the liver is less clear. The goal of this study was to examine the effect of TZDs on GNG. RESEARCH DESIGN AND METHODS: Twenty sulfonylurea-treated type 2 diabetic subjects were randomly assigned (double-blind study) to receive pioglitazone (PIO group; 45 mg/day) or placebo (Plc group) for 4 months to assess endogenous glucose production (EGP) (3-(3)H-glucose infusion), GNG (D2O technique), and insulin sensitivity by two-step hyperinsulinemic-euglycemic clamp (240 and 960 pmol/min per m2). RESULTS: Fasting plasma glucose (FPG) (10.0 +/- 0.8 to 7.7 +/- 0.7 mmol/l) and HbA1c (9.0 +/- 0.4 to 7.3 +/- 0.6%) decreased in the PIO and increased in Plc group (P < 0.05 PIO vs. Plc). Insulin sensitivity increased approximately 40% during high insulin clamp after pioglitazone (P < 0.01) and remained unchanged in the Plc group (P < 0.05 PIO vs. Plc). EGP did not change, while GNG decreased in the PIO group (9.6 +/- 0.7 to 8.7 +/- 0.6 micromol x min(-1) x kg(ffm)(-1)) and increased in the Plc group (8.0 +/- 0.5 to 9.6 +/- 0.8) (P < 0.05 PIO vs. Plc). Change in FPG correlated with change in GNG flux (r = 0.63, P < 0.003) and in insulin sensitivity (r = 0.59, P < 0.01). Plasma adiponectin increased after pioglitazone (P < 0.001) and correlated with delta FPG (r = -0.54, P < 0.03), delta GNG flux (r = -0.47, P < 0.05), and delta insulin sensitivity (r = 0.65, P < 0.005). Plasma free fatty acids decreased after pioglitazone and correlated with delta GNG flux (r = 0.54, P < 0.02). From stepwise regression analysis, the strongest determinant of change in FPG was change in GNG flux. CONCLUSIONS: Pioglitazone improves FPG, primarily by reducing GNG flux in type 2 diabetic subjects.

Circulating soluble receptor for advanced glycation end products is inversely associated with glycemic control and S100A12 protein.

CONTEXT: The interaction of advanced glycation end products, including Nepsilon-(carboxymethyl)lysine-protein adducts (CML) and S100A12 protein, with their cellular receptor (RAGE) is implicated in the pathogenesis of diabetic vascular complications. RAGE has a circulating secretory receptor form, soluble RAGE (sRAGE), which, by neutralizing the action of advanced glycation end products, might exert a protective role against the development of cardiovascular disease. OBJECTIVE: The objective of the study was to investigate whether plasma sRAGE levels are associated with glycemic control, proinflammatory factors, or circulating ligands of RAGE such as plasma CML and S100A12 protein. STUDY DESIGN: We studied 160 subjects, 84 subjects with type 2 diabetes (aged 60 +/- 7 yr) and 76 nondiabetic controls (aged 45 +/- 10 yr). RESULTS: Plasma sRAGE was lower in diabetic patients than controls [141 (53-345) vs. 735 (519-1001) pg/ml, median (interquartile range), P < 0.0001], whereas CML levels were higher in diabetic patients than controls [67.9 (46.0-84.7) vs. 43.4 (28.0-65.0) microg/ml, P < 0.0001]. In stepwise regression analysis of the whole data set, hemoglobin A1c, insulin resistance (as homeostasis model assessment), and C-reactive protein were independently associated with plasma sRAGE, whereas age was not. In a subgroup of 26 diabetic and 24 nondiabetic subjects of similar age (54 +/- 3 yr), plasma S100A12 levels were higher in diabetic subjects [49 (39-126) vs. 28 (21-39) ng/ml]. Moreover, low sRAGE and high S100A12 were strongly associated with increased risk for cardiovascular disease (Framingham score). In this subgroup, the plasma S100A12 level was the only determinant of plasma sRAGE concentration. CONCLUSION: Plasma level of sRAGE is down-regulated in chronic hyperglycemia; among its ligands, S100A12 protein, but not CML, appears to be associated with this effect.

18F-FDG assessment of glucose disposal and production rates during fasting and insulin stimulation: a validation study.

UNLABELLED: The glucose analog (18)F-FDG is commonly used to quantify regional glucose uptake in vivo. The aim of this study was to test whether the analysis of plasma (18)F-FDG kinetics could be used to estimate endogenous glucose production (EGP) and the total rate of appearance (Ra), total rate of disappearance (Rd), and the metabolic clearance rate (MCR) of glucose. METHODS: Fourteen pigs were coinjected with (18)F-FDG and 6,6-(2)H-glucose ((2)H-G) during fasting (n = 6) and during physiologic (1.0 mU.kg(-1).min(-1), n = 4) and supraphysiologic (5.0 mU.kg(-1).min(-1), n = 4) euglycemic hyperinsulinemia. Arterial plasma was sampled for 180 min to quantify the parameters for the 2 tracers. RESULTS: Fasting Rd((2))(H-G) and Rd(FDG) were 12.3 +/- 2.1 and 13.3 +/- 1.3 micromol.kg(-1).min(-1) (difference not statistically significant [NS]). M values were more than doubled between the 2 clamp studies (P < 0.0001). Rd((2))(H-G) and Rd(FDG) were dose-dependently higher during the hyperinsulinemic state (19.8 +/- 3.7 vs. 18.9 +/- 1.1 and 31.4 +/- 4.1 vs. 31.9 +/- 2.3 in 1.0 and 5.0 mU.kg(-1).min(-1) studies, respectively; difference between tracers NS) than during the fasting state, with a parallel suppression of EGP((2))(H-G) and EGP(FDG). Parameters estimated by (18)F-FDG and (2)H-G were equivalent in all groups; their agreement was confirmed by Bland-Altman examination. Total Rd(FDG) correlated with Rd((2))(H-G) (r = 0.74; P = 0.003), M (r = 0.92; P = 0.001), MCR((2))(H-G) (r = 0.52; P = 0.037), and EGP((2))(H-G) (r = -0.71; P = 0.004). EGP(FDG) correlated with EGP((2))(H-G) (r = 0.62; P = 0.018), Rd((2))(H-G) (r = -0.78; P = 0.001), and MCR((2))(H-G) (r = -0.67; P = 0.008). The (18)F-FDG mean transit time correlated inversely with the M and Rd values and positively with EGP. CONCLUSION: The glucose analog (18)F-FDG can be used in the simultaneous estimation of whole-body glucose turnover and production and regional (18)F-FDG PET measurements under both fasting and insulin-stimulated conditions.

Separate contribution of diabetes, total fat mass, and fat topography to glucose production, gluconeogenesis, and glycogenolysis.

The contribution of increased gluconeogenesis (GNG) to the excessive rate of endogenous glucose production (EGP) in type 2 diabetes (T2DM) is well established. However, the separate effects of obesity (total body fat), visceral adiposity, and T2DM have not been investigated. We measured GNG (by the (2)H(2)O technique) and EGP (with 3-(3)H-glucose) after an overnight fast in 44 type 2 diabetic and 29 gender/ethnic-matched controls. Subjects were classified as obese (body mass index 30 kg/m(2) or greater) or nonobese (body mass index < 30 kg/m(2)); diabetic subjects were further subdivided according to the severity of fasting hyperglycemia [fasting plasma glucose (FPG) < 9 mm or >or= 9 mm]. EGP was similar in nondiabetic controls and T2DM with FPG less than 9 mm but was increased in T2DM with FPG >or= 9 mm (P < 0.001). Within the diabetic groups, obesity had an independent effect to further increase basal EGP (P < 0.01). In both nonobese diabetic groups, both the percent GNG and gluconeogenic flux were increased, compared with nonobese nondiabetic controls. In both diabetic groups, obesity further increased both percent GNG and gluconeogenic flux. In obese and nonobese T2DM, the increase in gluconeogenic flux was not accompanied by a reciprocal decrease in glycogenolysis, indicating a loss of hepatic autoregulation. By multivariate analysis, gluconeogenic flux was positively correlated with percent body fat, visceral fat, and the fasting plasma free fatty acid and glucose concentrations (all P