Association of osteocalcin, osteoprotegerin, and osteopontin with cardiovascular disease and retinopathy in type 2 diabetes.

BACKGROUND: Novel biomarkers of vascular disease in diabetes could help identify new mechanistic pathways. Osteocalcin, osteoprotegerin, and osteopontin are key molecules involved in bone and vascular calcification processes, both of which are compromised in diabetes. We aimed to evaluate possible associations of osteocalcin, osteoprotegerin, and osteopontin with cardiovascular disease (CVD) and diabetic retinopathy (DR) among people with type 2 diabetes (T2D). MATERIALS AND METHODS: Osteocalcin, osteoprotegerin, and osteopontin concentrations were measured at enrolment in 848 participants with T2D from the Sapienza University Mortality and Morbidity Event Rate (SUMMER) Study (ClinicalTrials.gov: NCT02311244). Logistic regression models and propensity score matching were used to assess possible associations of osteocalcin, osteoprotegerin, and osteopontin with a history of CVD and with evidence of any grade of DR adjusting for confounders. RESULTS: Previous CVD was reported in 139 (16.4%) participants, while 144 (17.0%) had DR. After adjusting for possible confounders, osteocalcin but not osteoprotegerin or osteopontin concentrations were associated with a history of CVD (Odds Ratio [OR] and 95% CI for one standard deviation (SD) increase in osteocalcin concentrations (natural log): 1.35 (1.06-1.72), p = 0.014). Associations with prevalent DR were seen for osteoprotegerin (OR for one SD increase in osteoprotegerin concentrations (natural log): 1.25 (1.01-1.55), p = 0.047) and osteopontin (OR for one SD increase in osteopontin concentrations (natural log): 1.25 (1.02-1.53), p = 0.022), but not osteocalcin. CONCLUSIONS: In T2D, higher serum osteocalcin concentrations are associated with macrovascular complications and higher osteoprotegerin and osteopontin concentrations with microvascular complications, suggesting that these osteokines might be involved in pathways directly related to vascular disease.

Circulating pro-neurotensin levels predict bodyweight gain and metabolic alterations in children.

BACKGROUND AND AIMS: Neurotensin (NT) is an intestinal peptide released after fat ingestion, which regulates appetite and facilitates lipid absorption. Elevated plasma levels of its stable precursor pro-neurotensin (pro-NT) are associated with type 2 diabetes, obesity and cardiovascular mortality in adult populations; no data on pro-NT and metabolic disease are available in children. Aim of the study was to evaluate plasma pro-NT in relation to the presence of obesity in children, and to test if high pro-NT associates with the development of metabolic impairment later in life. METHODS AND RESULTS: For this longitudinal retrospective study, we studied 151 overweight/obese children undergoing metabolic evaluations at University of Cagliari, Italy. Pro-NT was also assessed in 46 normal-weight, age-, sex-comparable normal-weight children, selected as a reference group. At the baseline, pro-NT was comparable between overweight/obese and normal-weight children and correlated positively with age (p < 0.001), triglycerides (p < 0.001) and inversely with HDL levels (p = 0.008). Plasma pro-NT associated with high triglycerides with OR = 5.9 (95%CI: 1.24-28.1; p = 0.026) after adjustment for multiple confounders. At the 6.5-year follow-up, high basal pro-NT associated with impaired ß-cell function to compensate for insulin-resistance (disposition index: r = -0.19, p = 0.035) and predicted bodyweight increase, as indicated by percentage change of standard deviation score BMI (median(95%CI) = +20.8(+4.9-+27.5)% in the highest tertile), independently from age, sex, triglycerides and insulin-resistance (standardized ß = 0.24; p = 0.036). CONCLUSIONS: Elevated pro-NT levels in children are significantly associated with weight gain later in life and may represent a marker of susceptibility to metabolic impairment in presence of obesity.

Independent association of atherogenic dyslipidaemia with all-cause mortality in individuals with type 2 diabetes and modifying effect of gender: a prospective cohort study.

BACKGROUND: Atherogenic dyslipidaemia has been implicated in the residual risk for cardiovascular morbidity and mortality, which remains despite attainment of LDL cholesterol goals especially in individuals with type 2 diabetes. However, its relationship with all-cause death has not been sufficiently explored. This analysis evaluated the independent association of increased triglycerides and triglyceride:HDL cholesterol ratio (TG:HDL) and decreased HDL cholesterol with total mortality and the possible modifying effect of gender in a large cohort of patients with type 2 diabetes. METHODS: This observational, prospective study enrolled 15,773 patients in 19 Diabetes Clinics throughout Italy in the years 2006-2008. Triglycerides and total and HDL cholesterol were measured by colorimetric enzymatic methods. Vital status was retrieved on 31 October 2015 for 15,656 patients (99.3%). Participants were stratified by quartiles of triglycerides, HDL cholesterol, and TG:HDL. RESULTS: There were 3,602 deaths over a follow-up 7.42 ± 2.05 years (31.0 × 1000 person-years). In the unadjusted analyses, the highest TG:HDL (but not triglyceride) and the lowest HDL cholesterol quartile were associated with increased death rate and mortality risk. When sequentially adjusting for confounders, including total, LDL, or non-HDL cholesterol and lipid-lowering treatment, mortality risk was significantly higher in the highest triglyceride (hazard ratio 1.167 [95% confidence interval 1.055-1.291], p = 0.003) and TG:HDL (1.192 [1.082-1.314], p < 0.0001) and the lowest HDL cholesterol (1.232 [1.117-1.360], p < 0.0001) quartile, though the association of triglycerides and HDL cholesterol disappeared after further adjustment for each other. Interaction with gender was significant only for HDL cholesterol (p = 0.0009). The relationship with death was stronger for triglycerides in males and HDL cholesterol in females, with these associations remaining significant even after adjustment for HDL cholesterol (1.161 [1.019-1.324], p = 0.025, for the highest vs the lowest triglyceride quartile) and triglycerides (1.366 [1.176-1.587], p < 0.0001, for the lowest vs the highest HDL cholesterol quartile). CONCLUSIONS: In patients with type 2 diabetes, higher triglycerides and TG:HDL and lower HDL cholesterol were independently associated with increased all-cause mortality, with a modifying effect of gender for triglycerides and HDL cholesterol. These data suggest that atherogenic dyslipidaemia, especially TG:HDL, may serve as predictor of all-cause death in these individuals. Trial registration ClinicalTrials.gov, NCT00715481, 15 July, 2008.

Uric acid, impaired fasting glucose and impaired glucose tolerance in youth with overweight and obesity.

BACKGROUND AND AIM: The relationships between uric acid (UA) and prediabetes is poorly explored in youth. We investigated the association between UA, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), insulin resistance (IR) and low insulin sensitivity (IS) in youth with overweight/obesity (OW/OB). METHODS AND RESULTS: A cross-sectional study was performed in 2248 youths with OW/OB (age 5-17 years). The sample was stratified in sex-specific quintiles (Q1 to Q5) of UA and the associations with fasting (FG), 2-h post-load glucose (2H-PG), IR and low IS were investigated. IR and low IS were estimated by assessment model of insulin resistance (HOMA-IR) and whole-body IS index (WBISI), respectively. IFG was defined as FG ≥ 100 < 126 mg/dL, IGT as 2H-PG ≥140 < 200 mg/dL, IR as HOMA-IR ≥75th percentile and low IS as WBISI ≤25th percentile by sex. Age, body mass index z-score, 2H-PG, HOMA-IR and WBISI, increased across sex-quintiles of UA while FG did not. The prevalence of IFG and IR were significantly increased in Q5 vs Q1 (reference quartile, P < 0.025). The prevalence of IGT increased from Q3 to Q5 vs Q1 (P < 0.025-0.0001) and that of low IS from Q2 to Q5 vs Q1 (P < 0.005-0.0001). CONCLUSIONS: In youth with OW/OB, rates of IGT and low IS increased progressively across quintiles of UA. On the contrary, IFG and IR were associated only with the highest quintile of UA. Our data suggest that UA is a biomarker of impaired glucose metabolism prevalently in post-challenge condition rather than in fasting state.

The American Academy of Pediatrics hypertension guidelines identify obese youth at high cardiovascular risk among individuals non-hypertensive by the European Society of Hypertension guidelines.

BACKGROUND: Two different systems for the screening and diagnosis of hypertension (HTN) in children currently coexist, namely, the guidelines of the 2017 American Academy of Pediatrics (AAP) and the 2016 European Society for Hypertension (ESH). The two systems differ in the lowered cut-offs proposed by the AAP versus ESH. OBJECTIVES: We evaluated whether the reclassification of hypertension by the AAP guidelines in young people who were defined non-hypertensive by the ESH criteria would classify differently overweight/obese youth in relation to their cardiovascular risk profile. METHODS: A sample of 2929 overweight/obese young people (6-16 years) defined non-hypertensive by ESH (ESH-) was analysed. Echocardiographic data were available in 438 youth. RESULTS: Using the AAP criteria, 327/2929 (11%) young people were categorized as hypertensive (ESH-/AAP+). These youth were older, exhibited higher body mass index, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), triglycerides, total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C) ratio, blood pressure, left ventricular mass index and lower HDL-C (p <0.025-0.0001) compared with ESH-/AAP-. The ESH-/AAP+ group showed a higher proportion of insulin resistance (i.e. HOMA-IR ≥3.9 in boys and 4.2 in girls) 35% vs. 25% (p <0.0001), high TC/HDL-C ratio (≥3.8 mg/dl) 35% vs. 26% (p = 0.001) and left ventricular hypertrophy (left ventricular mass index ≥45 g/h2.16) 67% vs. 45% (p = 0.008) as compared with ESH-/AAP-. CONCLUSIONS: The reclassification of hypertension by the AAP guidelines in young people overweight/obese defined non-hypertensive by the ESH criteria identified a significant number of individuals with high blood pressure and abnormal cardiovascular risk. Our data support the need of a revision of the ESH criteria.

Greater circulating DPP4 activity is associated with impaired flow-mediated dilatation in adults with type 2 diabetes mellitus.

BACKGROUND AND AIM: Dipeptidyl peptidase 4 (DPP4) is a key enzyme involved in the regulation of the incretin system exerted by cleaving the glucagon-like peptide 1 (GLP-1); the blockage of DPP4, exerted by the antidiabetic agents DPP4-inhibitors (DPP4-I), results in greater GLP-1 concentration and improved glycaemic control. DPP4 acts also as a pro-inflammatory molecule and mediates vascular damage in experimental models. The relationship between DPP4 activity and endothelial function in diabetes has not been explored yet. Aim of this study was to investigate systemic plasma DPP4 activity in relation to endothelial function in patients with type 2 diabetes mellitus (T2DM). METHODS AND RESULTS: Sixty-two T2DM individuals were recruited in our Diabetes outpatient clinics, Sapienza University, Rome, Italy. All participants underwent complete clinical work-up; endothelial function was evaluated by flow-mediated dilatation (FMD) test; plasma DPP4 activity was assessed by measuring the 7-amino-4-methylcoumarin (AMC) cleavage rate from the synthetic substrate H-glycyl-prolyl-AMC and compared with DPP4 activity measured in sixty-two age-, sex-, BMI-matched non-diabetic subjects. Patients with T2DM had significantly higher DPP4 activity than non-diabetic individuals (211,466 ± 87657 vs 158,087 ± 60267 nmol/min/ml, p < 0.001); in T2DM patients, greater DPP4 activity significantly correlated with lower FMD whereas was not associated with BMI and metabolic control. Greater systemic DPP4 activity was an independent predictor of reduced FMD after adjusting for age, gender and other confounders. CONCLUSIONS: Circulating DPP4 activity is increased in individuals with T2DM and associated with signs of endothelial dysfunction such as impaired FMD. DPP4 may negatively affect endothelial function through mechanisms beyond glucose homeostasis and metabolic control.

Urban diabetes: the case of the metropolitan area of Rome.

BACKGROUND: The world is rapidly urbanizing, causing alarming health problems to their citizens. The Cities Changing Diabetes program aims to address the social factors and cultural determinants that can increase type 2 diabetes (T2D) vulnerability among people living in cities. METHODS: Public data of Italian Institute for Statistics (ISTAT) and available scientific reports were reviewed and findings integrated. The prevalence of T2D in the 8 health districts of Rome was mapped and the correlation between prevalence and social and cultural determinants was assessed. RESULTS: The metropolitan area of Rome has 4.3 million inhabitants. People over 65 has increased by 136,000 units in the last decade, reaching 631,000 citizens in 2015. Elderly people living alone are 28.4%. The obesity prevalence is 9.3%, as compared to 8.2% in the year 2000. The prevalence of T2D is 6.6%, varying in the different 8 health districts between 5.9% and 7.3%. A linear correlation exists between the prevalence of diabetes in the districts, unemployment rate and use of private transportation rate (Pearson R 0.52 and 0.60, respectively), while an inverse correlation is present with aging index, school education level, and slow mobility rate (Person R -0.57, -0.52, and -0.52, respectively). CONCLUSIONS: Important socio-demographic changes have occurred in Rome during the last decades with a raise in the prevalence of obesity and diabetes. A wide variation exists in the prevalence of T2D among the districts of Rome, associated with social and cultural determinants. This study model can help rethinking diabetes in an urban setting.

Is resistant hypertension an independent predictor of all-cause mortality in individuals with type 2 diabetes? A prospective cohort study.

BACKGROUND: Resistant hypertension is independently associated with an increased risk of death in the general hypertensive population. We assessed whether resistant hypertension is an independent predictor of all-cause mortality in individuals with type 2 diabetes from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study. METHODS: On 31 October 2015, vital status information was retrieved for 15,656 of the 15,773 participants enrolled in 2006-2008. Based on baseline blood pressure (BP) values and treatment, participants were categorized as normotensive, untreated hypertensive, controlled hypertensive (i.e., on-target with < 3 drugs), uncontrolled hypertensive (i.e., not on-target with 1-2 drugs), or resistant hypertensive (i.e., uncontrolled with > 3 drugs or controlled with > 4 drugs). Kaplan-Meier and Cox proportional hazards regression analyses were used to assess the association with all-cause mortality. RESULTS: Using the 130/80 mmHg targets for categorization, crude mortality rates and Kaplan-Meier estimates were highest among resistant hypertension participants, especially those with controlled resistant hypertension. As compared with resistant hypertension, risk for all-cause mortality was significantly lower for all the other groups, including individuals with controlled hypertension (hazard ratio 0.81 [95% confidence interval 0.74-0.89], P < 0.0001), but became progressively similar between resistant and controlled hypertension after adjustment for cardiovascular risk factors and complications/comorbidities. Also when compared with controlled resistant hypertension, mortality risk was significantly lower for all the other groups, including controlled hypertension, even after adjusting for cardiovascular risk factors (0.77 [0.63-0.95], P = 0.012), but not for complications/comorbidities (0.88 [0.72-1.08], P = 0.216). BP was well below target in the controlled hypertensive groups (resistant and non-resistant) and values < 120/70 mmHg were associated with an increased mortality risk. Results changed only partly when using the 140/90 mmHg targets for categorization. CONCLUSIONS: In the RIACE cohort, at variance with the general hypertensive population, resistant hypertension did not predict death beyond target organ damage. Our findings may be explained by the high mortality risk conferred by type 2 diabetes and the low BP values observed in controlled hypertensive patients, which may mask risk associated with resistant hypertension. Less stringent BP goals may be preferable in high-risk patients with type 2 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00715481 , retrospectively registered 15 July, 2008.

Relationship between adipose tissue dysfunction, vitamin D deficiency and the pathogenesis of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. Its pathogenesis is complex and not yet fully understood. Over the years many studies have proposed various pathophysiological hypotheses, among which the currently most widely accepted is the "multiple parallel hits" theory. According to this model, lipid accumulation in the hepatocytes and insulin resistance increase the vulnerability of the liver to many factors that act in a coordinated and cooperative manner to promote hepatic injury, inflammation and fibrosis. Among these factors, adipose tissue dysfunction and subsequent chronic low grade inflammation play a crucial role. Recent studies have shown that vitamin D exerts an immune-regulating action on adipose tissue, and the growing wealth of epidemiological data is demonstrating that hypovitaminosis D is associated with both obesity and NAFLD. Furthermore, given the strong association between these conditions, current findings suggest that vitamin D may be involved in the relationship between adipose tissue dysfunction and NAFLD. The purpose of this review is to provide an overview of recent advances in the pathogenesis of NAFLD in relation to adipose tissue dysfunction, and in the pathophysiology linking vitamin D deficiency with NAFLD and adiposity, together with an overview of the evidence available on the clinical utility of vitamin D supplementation in cases of NAFLD.

The vitamin D receptor functional variant rs2228570 (C>T) does not associate with type 2 diabetes mellitus.

AIM: Vitamin D acts through the binding to the vitamin D receptor (VDR). Several polymorphisms in VDR gene have been studied. Among these, the rs2228570 C>T (FokI) variant has been demonstrated to be functional, leading to a protein with a different size and activity. So far, genetic studies on the association between VDR gene rs2228570 single nucleotide polymorphism (SNP) and type 2 diabetes mellitus (T2DM) showed contradictory results. Thus, we performed an association study in a large cohort of adult Italian subjects with T2DM and in nondiabetic controls. MATERIALS AND METHODS: For this study, 1713 subjects, 883 T2DM patients and 830 controls, were genotyped for the polymorphism. All participants without a diagnosis of diabetes underwent oral glucose tolerance test (OGTT), with measurement of glucose and insulin levels. Indices of insulin resistance (Homeostatic model assessment of insulin resistance, insulin sensitivity index), secretion (homeostatic model assessment for beta-cell, corrected insulin response at 30 minutes) and disposition index were calculated. RESULTS: Genotype distributions and allele frequencies did not show difference between T2DM subjects and controls. We did not find significant differences among the three genotypes regarding gender, age, BMI, waist, hip, waist-to-hip ratio, and blood pressure. There were also no significant differences in lipid parameters, aspartate aminotransferase, and alanine aminotransferase levels. We tested for association with OGTT-derived data and surrogate indices of insulin resistance and secretion. We did not find significant differences among the genotypes in any of above-mentioned parameters. Furthermore, vitamin D levels were measured in a subgroup of subjects. We did not find significant differences among the genotypes. CONCLUSIONS: Our study does not provide evidence for the association of the rs2228570 polymorphism with T2DM in a Caucasian population.

The perilipin 2 (PLIN2) gene Ser251Pro missense mutation is associated with reduced insulin secretion and increased insulin sensitivity in Italian obese subjects.

BACKGROUND: Perilipin 2 (PLIN2), a member of the family of perilipin lipid droplets coating proteins, is very widely expressed. The Ser251Pro (rs35568725) missense mutation in exon 6 of PLIN2 gene was previously associated with increased lipid accumulation, decreased lipolysis and increased number of small lipid droplets per cell. Furthermore, the Pro251 mutation was associated with decreased plasma triglyceride and very low density lipoprotein concentrations in population studies. The aim of this study was to evaluate the effect of the Ser251Pro mutation of PLIN2 gene in a cohort with a higher predisposition to obesity-associated metabolic alterations, such as insulin resistance, decreased insulin-secretion, hyperglycaemia, and dyslipidaemia. METHODS: A large cohort (N = 1692) of Italian obese subjects (mean body mass index = 41 kg/m(2) ) was genotyped for the Ser251Pro mutation. All participants underwent oral glucose tolerance tests (OGTT), with measurement of glucose and insulin levels. Indices of insulin resistance and of insulin secretion were also calculated. Clinical and biochemical parameters were collected for all participants. RESULTS: We observed that insulin concentration was significantly reduced at 120 min after the administration of glucose in Pro251 allele carriers, whereas glucose levels were similar in Pro251 allele carriers and non-carriers throughout the OGTT. Furthermore, the CIR120 index of insulin secretion was significantly lower (P < 0.035) and the ISI index of insulin-sensitivity was significantly higher (P < 0.031) in carriers of the Pro251 allele. When we analysed men and women separately to test for gender-specific associations, we observed that in women insulin levels were significantly lower in Pro251 allele carriers compared with wild-type subjects throughout the whole OGTT. In men, we confirmed a significant reduction in insulin concentration only at 120 min after the OGTT. No significant differences between genotype groups regarding triglyceride levels and anyother clinical and metabolic parameters were observed. CONCLUSION: We observed a strong significant association between the PLIN2 Pro251 mutation and lower insulin secretion associated with an increased insulin sensitivity. Copyright © 2015 John Wiley & Sons, Ltd.

Resistant hypertension in patients with type 2 diabetes: clinical correlates and association with complications.

OBJECTIVE: The phenotype of resistant hypertension in patients with type 2 diabetes has been poorly characterized. This cross-sectional analysis of the large cohort from the Renal Insufficiency and Cardiovascular Events (RIACE) study was aimed at assessing the clinical correlates and association with complications of resistant hypertension in patients with type 2 diabetes. METHODS: The RIACE study enrolled 15,773 patients consecutively visiting 19 diabetes clinics during the years 2007-2008. Resistant hypertension, defined as BP values not on target (i.e. >130/80 mmHg, respectively) with three antihypertensive agents, was detected in 2363 individuals (15% of the whole RIACE cohort, 17.4% of hypertensive individuals, and 21.2% of treated hypertensive patients). Patients without resistant hypertension [nonresistant hypertension (NRH)], that is on target with one (n = 1569), two (n = 1369), and three (n = 803) drugs, and individuals with uncontrolled hypertension, that is untreated or not on target with less than three drugs (n = 7440), served as controls. RESULTS: As compared with NRH and uncontrolled hypertension patients, patients with resistant hypertension were older and more frequently women and had significantly higher waist circumference, albuminuria, and serum creatinine, and lower glomerular filtration rate. Prevalence values of chronic kidney disease and advanced retinopathy were significantly higher in resistant hypertension than in both nonresistant hypertension and uncontrolled hypertension individuals, whereas cardiovascular disease was more frequent in resistant hypertension versus uncontrolled hypertension, but not nonresistant hypertension patients, especially those on 2-3 drugs. CONCLUSIONS: Resistant hypertension is relatively common in patients with type 2 diabetes. In these individuals, age, female sex and waist circumference are independent correlates of resistant hypertension, which is strongly associated with microvascular (especially renal) disease, whereas relation with macrovascular complications is unclear.

Association of RXR-Gamma Gene Variants with Familial Combined Hyperlipidemia: Genotype and Haplotype Analysis.

Background. Familial combined hyperlipidemia (FCHL), the most common genetic form of hyperlipdemia, is characterized by a strong familial clustering and by premature coronary heart disease. The FCHL locus has been mapped to human chromosome 1q21-q23. This region includes the retinoid X receptor gamma (RXRG), a nuclear factor member of the RXR superfamily, which plays important roles in lipid homeostasis. Objective. To investigate the possible role of the RXRG gene in the genetic susceptibility to FCHL. Methods. Variations in RXRG gene were searched by direct sequencing, and the identified SNPs were genotyped by PCR-RFLP in 192 FCHL individuals from 74 families and in 119 controls. Results. We identified 5 polymorphisms in the RXRG gene (rs1128977, rs2651860, rs2134095, rs283696, and rs10918169). Genotyping showed that the A-allele of rs283696 SNP was significantly associated with FCHL (corrected P, P c < 0.01). Also the alleles of the rs10918169 and of the rs2651860 SNP were more frequent in FCHL subjects compared to those in controls, although not significantly after correction. When the clinical characteristics of the FCHL subjects were stratified by allele carrier status for each SNP, the rs2651860 SNP was significantly associated with increased levels of LDL-cholesterol and of Apo-B in T-allele carriers (P < 0.04). Finally, haplotypes analysis with all 5 SNPs confirmed the significant association of RXRG gene with FCHL. Specifically, the haplotype containing all 3 "at-risk" alleles, significantly associated with FCHL (A-allele of rs283696, G-allele of rs10918169, and T-allele of rs2651860), showed an OR (Odds Ratio) of 2.02, P c < 0.048. Conversely, the haplotype without all these 3 alleles was associated with a reduced risk for FCHL (OR = 0.39, P c < 0.023). The "at-risk" haplotype CTTAG was also associated with higher LDL-C (P < 0.015). In conclusion, variation in the RXRG gene may contribute to the genetic dyslipidemia in FCHL subjects.

Altered glucose homeostasis is associated with increased serum apelin levels in type 2 diabetes mellitus.

BACKGROUND: Apelin is an adipokine that plays a role in the regulation of glucose homeostasis and in obesity. The relationship between apelin serum concentration and dysmetabolic conditions such as type 2 diabetes (T2D) is still controversial. Aims of our study are: 1) determine the circulating levels of apelin in a large cohort of Italian subjects with T2D, T1D and in non-diabetic controls; 2) identify putative metabolic determinants of modified apelin concentrations, in order to search possible mechanism of apelin control; 3) investigate changes in apelin levels in response to sharp modifications of glucose/insulin metabolism in T2D obese subjects before and 3 days after bariatric surgery. METHODS: We recruited 369 subjects, 119 with T2D, 113 with T1D and 137 non-diabetic controls. All subjects underwent a complete clinical examination, including anthropometric and laboratory measurements. Serum apelin levels were determined by EIA (immunoenzyme assay). RESULTS: Patients with T2D had significantly higher serum apelin levels compared to controls (1.23 ± 1.1 ng/mL vs 0.91 ± 0.7 ng/mL, P<0.001) and to T1D subjects (0.73 ± 0.39 ng/mL, P<0.001). Controls and T1D subjects did not differ significantly in apelin levels. Apelin concentrations were directly associated with fasting blood glucose (FBG), body mass index (BMI), basal Disposition Index (DI-0), age, and diagnosis of T2D at bivariate correlation analysis. Multiple regression analysis confirmed that diagnosis of T2D, basal DI-0 and FBG were all determinants of serum apelin levels independently from age and BMI. Bariatric surgery performed in a subgroup of obese diabetic subjects (n = 12) resulted in a significant reduction of apelin concentrations compared to baseline levels (P = 0.01). CONCLUSIONS: Our study demonstrates that T2D, but not T1D, is associated with increased serum apelin levels compared to non-diabetic subjects. This association is dependent on impaired glucose homeostasis, and disappears after bariatric surgery, providing further evidence regarding the relationship between apelin and the regulation of glucose metabolism.

Lack of effect of apolipoprotein C3 polymorphisms on indices of liver steatosis, lipid profile and insulin resistance in obese Southern Europeans.

BACKGROUND: Apolipoprotein C3 (APOC3) is a component of triglyceride-rich lipoproteins, and APOC3 rs2854116 and rs2854117 polymorphisms have been associated with non-alcoholic fatty liver disease, hypertriglyceridaemia, and insulin-resistance. OBJECTIVE: To determine if the APOC3 variants alter the susceptibility of obese subjects to develop liver damage, hypertrigliceridaemia, and insulin-resistance. METHODS: The study was carried out on 585 unrelated obese Italians (median body mass index BMI = 41 kg/m2) who were genotyped for the rs2854116 and rs2854117 variants. All participants underwent oral glucose tolerance tests (OGTT), with measurement of glucose, insulin, lipid parameters. Indices of insulin-resistance (HOMA and ISI) were calculated. Alanine transaminase (ALT) and aspartate transaminase (AST) were used as markers of liver injury. RESULTS: The study subjects were divided into two groups: those homozygous for the wild-type alleles at both SNPs (-482C and -455T alleles) and those who were carriers of at least one variant allele or both (-482T, -455C or both). Also each SNP was analysed independently. No significant differences were found in ALT and AST levels and in the lipid profile between the two groups. Insulin concentrations, glucose tolerance and insulin sensitivity were similar in the two groups. CONCLUSION: We did not identify any significant association between APOC3 polymorphisms and fatty liver disease, lipids, and insulin-resistance in obese subjects, thus not confirming the suggested role of these APOC3 gene sequence variants.

The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation provides a better definition of cardiovascular burden associated with CKD than the Modification of Diet in Renal Disease (MDRD) Study formula in subjects with type 2 diabetes.

OBJECTIVE: The chronic kidney disease (CKD)-Epidemiology Collaboration (EPI) equation was shown to be more accurate than the Modification of Diet in Renal Disease (MDRD) Study formula for estimating glomerular filtration rate (GFR) in the general population. This study was aimed at assessing cardiovascular disease (CVD) burden associated with CKD in type 2 diabetes, using these two GFR estimating formulas for CKD definition. METHODS: This cohort study examined 15,773 Caucasian patients with type 2 diabetes participating in the Renal Insufficiency And Cardiovascular Events Italian Multicenter Study (NCT00715481) and attending the baseline visit in 19 diabetes clinics in years 2007-2008. Serum creatinine was assessed by the modified Jaffe method. Albuminuria was measured by immunonephelometry or immunoturbidimetry. CKD was defined as an estimated GFR (eGFR) <60 mL/min/1.73 m(2) and/or micro/macroalbuminuria. RESULTS: Prevalence of impaired eGFR and CKD decreased from 18.7% to 17.2% (P=0.0012) and from 37.5% to 36.3% (P=0.077), respectively, with the CKD-EPI, as compared with the MDRD Study equation. Subjects with impaired eGFR or CKD with the MDRD Study equation only showed lower CVD prevalence rates and coronary heart disease risk scores, mainly driven by prevailing female sex, younger age and shorter diabetes duration, as compared with those with both formulas, whereas opposite figures were observed in patients falling into these categories with the CKD-EPI equation only. CONCLUSIONS: Estimating GFR in patients with type 2 diabetes using the CKD-EPI equation provides a better definition of CVD burden associated with CKD not only in individuals reclassified upward, but also in those reclassified downward.

The 148M allele of the PNPLA3 gene is associated with indices of liver damage early in life.

BACKGROUND & AIMS: Childhood obesity is a growing problem worldwide. Non-alcoholic fatty liver disease (NAFLD) is frequently associated with obesity in children. Recently, the PNPLA3 gene I148M (rs738409) variant was demonstrated to be strongly associated with hepatic steatosis in obese adults. In this study we add further insight into the role of PNPLA3 by exploring whether this association begins early in life in obese children or becomes manifest only in adulthood. METHODS: Four hundred and seventy-five obese/overweight children and adolescents were genotyped for the I148M allele. Clinical and biochemical parameters were collected for all participants, including indices of hepatic injury, glucose tolerance and insulin resistance. Ultrasound imaging of the liver was obtained to assess the degree of steatosis in a subset of children. RESULTS: Carriers of two 148M alleles had a 52% increase in circulating ALT levels compared to carriers of two 148I alleles, with individuals with one 148M allele showing a 9.5% increase (p=0.001). AST concentration was also significantly higher in carriers of two and one M alleles (17.4% and 4%, respectively, p=0.022). A total of 36% of carries of two 148M alleles showed elevated ALT, defined as >30U/L, compared to only 10% of carriers of two 148I alleles (p<0.001). Liver steatosis was more prevalent in carriers of two 148M alleles. Glucose tolerance and insulin sensitivity were similar across all three genotypes. CONCLUSIONS: Our data show that the PNPLA3 gene I148M variant is associated with increased levels of ALT/AST in obese children and adolescents, suggesting that it confers genetic susceptibility to liver damage from a young age.

Homozygosity for the Ala allele of the PPARγ2 Pro12Ala polymorphism is associated with reduced risk of coronary artery disease.

Several studies suggest that the peroxisome proliferator-activated receptor gamma (PPARγ) is involved in atherogenesis. The Pro12Ala polymorphism in the gene encoding PPARγ (PPARγ2 gene) influences the risk for type 2 diabetes. Two population-based studies have shown that the Ala allele is associated with reduced carotid intimal-medial thickness (IMT). However, studies focusing on acute clinical events have yielded conflicting results. Our aim was to evaluate the role of the Pro12Ala PPARγ2 polymorphism on the risk of coronary artery disease (CAD) in an Italian population with a case-controlled genetic association study in which 478 CAD patients and 218 controls were genotyped for the Pro12Ala polymorphism. CAD was diagnosed by angiography. We found that homozygotes for the Ala12 allele had a significantly reduced risk of CAD after adjusting for diabetes, sex, age, body mass index (BMI), smoking, lipids and hypertension (OR =0.007; 95% C.I. = 0.00-0.32 p< 0.011). In this case-control study, homozygosity for the Ala allele at codon 12 of the PPARγ2 gene resulted in reduced risk of CAD. This is consistent with reports from previous studies focusing on atherosclerosis and myocardial infarction.

Prevalence of type 1 diabetes autoantibodies (GADA, IA2, and IAA) in overweight and obese children.

OBJECTIVE: Little is known about the prevalence of beta-cell autoantibodies in children with excess body weight. The prevalence of type 1 diabetes autoantibodies and its relation with hyperglycemia was analyzed in 686 overweight/obese children and adolescents. RESEARCH DESIGN AND METHODS: All children underwent an oral glucose tolerance test, and anti-GAD, anti-IA2, and anti-IAA autoantibodies were measured. Autoantibody prevalence was evaluated in 107 normal-weight children for comparison. RESULTS: A single autoantibody was present in 2.18% of overweight/obese subjects and 1.86% normal-weight subjects (P = NS). Postload glycemia was significantly higher in antibody-positive children (133 +/- 69.9 vs. 105.4 +/- 17.7 mg/dl, P < 0.0001) compared with autoantibody-negative subjects. No difference in autoantibody distribution was seen when our cohort was stratified by age, sex, SDS-BMI, pubertal stage, and homeostasis model assessment-insulin resistance (HOMA-IR). CONCLUSIONS: The 2.18% prevalence of type 1 diabetes autoantibodies is similar to that reported in nonobese children. This study provided evidence that excess body weight and insulin resistance do not influence autoantibody frequency.