Mean platelet volume (MPV) as new marker of diabetic macrovascular complications in patients with different glucose homeostasis : Platelets in cardiovascular risk.

BACKGROUND: Platelets play an important role in the development of cardiovascular disease (CVD). Mean platelet volume (MPV) is considered as biological marker of platelets activity and function. The aim of the present study was to evaluate MPV values and its possible correlation with arterial stiffness and subclinical myocardial damage, in normal glucose tolerance patients (NGT), in newly diagnosed type 2 diabetic (T2DM) patients and in individuals with pre-diabetes. METHODS: We enrolled 400 newly diagnosed hypertensive patients. All patients underwent an Oral Glucose Tolerance test (OGTT). Arterial stiffness (AS) was evaluated with the measurement of carotid-femoral pulse wave velocity (PWV), augmentation pressure (AP) and augmentation index (AI). Echocardiographic recordings were performed using an E-95 Pro ultrasound system. RESULTS: Among groups there was an increase in fasting plasma glucose (FPG) (p < 0.0001), fasting plasma insulin (FPI) (p < 0.0001), high sensitivity c reactive protein (hs-CRP) levels (p < 0.0001) and a decrease in renal function as demonstrated by e-GFR values (p < 0.0001). From the NGT group to the T2DM group there was a rise in MPV value (p < 0.0001). Moreover, in the evaluation of arterial stiffness and subclinical myocardial damage, MPV showed a positive correlation with these parameters. CONCLUSIONS: In the present study we highlighted that MPV is significantly increased, not only in newly diagnosed T2DM patients, but also in early stage of diabetes, indicating that subjects with pre-diabetes present increased platelets reactivity. Moreover, our results suggest that MPV is associated with increased arterial stiffness and subclinical myocardial damage, indicating MPV as new marker of CV risk.

Osteopontin levels correlate with severity of diabetic cardiomyopathy in early stage of diabetes.

Diabetic cardiomyopathy (DbCM) is characterized by restrictive pattern and consistent risk of overt heart failure. We here focused osteopontin (OPN), which was tested independently associated with left ventricular diastolic dysfunction (LVDD). Overall, OPN increased with DbCM severity according with the presence of left atrial dilatation, LV hypertrophy and LVDD.

Serum proprotein convertase subtilisin/Kexin type 9 and vascular disease in type 2 diabetic patients.

BACKGROUND: Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) levels have been suggested as novel atherosclerotic biomarker. PCSK9 plays important roles in the pathogenesis of atherosclerosis by regulating the degradation of low-density lipoprotein receptor as well as different inflammatory pathways. Considering the important prognostic role of arterial stiffness in cardiovascular disease (CVD), the aim of the study is to investigate the correlation between PCSK9 levels and arterial stiffness in a cohort of diabetic patients, without previous CV events. METHODS: This cross-sectional analysis enrolled 401 Caucasian patients with type II diabetes mellitus (T2DM). PCSK9 levels were measured by ELISA test, arterial stiffness was estimated by measuring carotid-femoral pulse wave velocity (PWV). RESULTS: Patients were divided in three tertiles according to increasing value of PCSK9. From the I to the III tertiles, there was a significant increase in high sensitivity C-reactive protein (hs-CRP), fibrinogen and white blood cells (WBC) and a reduction in estimated glomerular filtration rate (e-GFR). Patients with higher levels of PCSK9 presented increased systolic, diastolic blood pressure, pulse pressure and PWV. PWV was significantly and directly correlated with PCSK9, fibrinogen, age, BMI and PP, and indirectly correlated with diet, lifestyle and e-GFR. Serum PCSK9 was the major predictor of PWV, justifying a 16.9% of its variation. CONCLUSION: Our study demonstrates a close association between circulating PCSK9 levels and PWV in T2DM subjects without previous CV events even after adjusting for well-known CV risk factor and pharmacological medications. Serum PCSK9 could be a useful biomarker for CV risk stratification in diabetic subjects.

Nox2 up-regulation and hypoalbuminemia in patients with type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is associated with oxidative stress but the underlying mechanisms promoting oxidative stress as well as its relationship with cardiovascular events is still unclear. In 375 T2DM patients who were followed-up for approximately 5 years we measured the serum levels of soluble NOX2-derived peptide (sNOX2-dp), a marker of Nox2 activation, and albumin, a powerful antioxidant protein. In the entire cohort soluble Nox2 and serum albumin were significantly correlated (r = -0.348, P < 0.0001). During the follow-up 49 cardiovascular events (CVE) were registered, of which 45 were non-fatal myocardial infarction (MI); patients with non-fatal MI had significantly higher soluble NOX2/albumin ratio compared to cardiovascular events-free patients. Cox regression analysis showed a significant association between sNox2-dp/serum albumin ratio and the incidental risk of non-fatal MI (HR 1.106, CI95% 1.020-1.198, P = 0.014). The study suggests that redox status imbalance negatively influences vascular outcomes in T2DM.

Alkaline phosphatase affects renal function in never-treated hypertensive patients: effect modification by age.

Several studies in patients with chronic kidney disease or normal renal function have shown that high levels of tissue non-specific alkaline phosphatase (ALP) are associated with an increased risk of all cause and cardiovascular (CV) mortality. Considering the independent prognostic role of renal function, we investigated the possible association between ALP levels and estimated glomerular filtration rate (e-GFR) in a large cohort of hypertensive subjects. We enrolled 2157 never-treated uncomplicated hypertensive patients with ALP levels within normal range. In the whole population, e-GFR was strongly related to ALP (r = -0.43, P < 0.0001) with similar magnitude in females and in males, resulting ALP the second independent predictor of renal function. In a multiple linear regression model, both on crude (P < 0.001) and adjusted (P = 0.01) analyses age significantly modified the effect of a fixed increase in ALP (20 UI/L) on renal function so that the reduction in e-GFR associated to a 20 UI/L increase in ALP was of lower magnitude in younger patients and progressively of higher extent from 20 years of age onwards. In conclusion, present data indicate a significant relationship between ALP levels and e-GFR in uncomplicated hypertensive patients that is modulated by age and that persisted after adjusting for several confounders.

Different Patterns of Left Ventricular Hypertrophy in Metabolically Healthy and Insulin-Resistant Obese Subjects.

Obese subjects showed different cardiovascular risk depending by different insulin sensitivity status. We investigated the difference in left ventricular mass and geometry between metabolically healthy (MHO) and unhealthy (MUHO) obese subjects. From a cohort of 876 obese subjects (48.3 ± 14.1 years) without cardio-metabolic disease and stratified according to increasing values of Matsuda index after 75 g oral glucose tolerance test, we defined MHO (n = 292) those in the upper tertile and MUHO (n = 292) those in the lower tertile. All participants underwent echocardiographic measurements. Left ventricular mass was calculated by Devereux equation and normalized by height2,7 and left ventricular hypertrophy (LVH) was defined by values >44 g/m2.7 for females and >48 g/m2.7 for males. Left ventricular geometric pattern was defined as concentric or eccentric if relative wall thickness was higher or lower than 0.42, respectively. MHO developed more commonly a concentric remodeling (19.9 vs. 9.9%; p = 0.001) and had a reduced risk for LVH (OR 0.46; p < 0.0001) than MUHO, in which the eccentric type was more prevalent (40.4 vs. 5.1%; p < 0.0001). We demonstrated that obese subjects-matched for age, gender and BMI-have different left ventricular mass and geometry due to different insulin sensitivity status, suggesting that diverse metabolic phenotypes lead to alternative myocardial adaptation.

HDL cholesterol is an independent predictor of ß-cell function decline and incident type 2 diabetes: A longitudinal study.

BACKGROUND: Experimental evidence indicates that high-density lipoprotein (HDL) may stimulate glucose uptake and improve ß-cell function. The aim of this study was to evaluate whether lower levels of HDL may affect the risk to develop type 2 diabetes. METHODS: Incident rate of type 2 diabetes and changes in insulin sensitivity and ß-cell function over 5.5-year follow-up were examined in 670 non-diabetic subjects stratified in tertiles according to basal HDL levels. RESULTS: As compared to the highest tertile of HDL, individuals with lower levels of HDL have an increased risk to develop type 2 diabetes independently from several cardiometabolic risk factors (odds ratio: 2.88, 95% confidence interval: 1.05-7.91), and exhibited a greater deterioration of ß-cell function, estimated by the disposition index, over 5.5-year follow-up. Conversely, changes in Matsuda index of insulin sensitivity over the follow-up were not significantly different amongst the three HDL groups. In a multivariable regression analysis model including age, sex, waist circumference, triglycerides, total cholesterol, C-reactive protein, fasting and 2-hour post-load glucose, family history of type 2 diabetes and smoking habit, HDL concentration at baseline was an independent predictor of ß-cell function decline over the follow-up (ß = .30, P = .0001). Mediation analysis showed that the association between lower HDL levels at baseline and increased risk of incident diabetes was mediated by ß-cell function deterioration during the follow-up (t = -3.32, P = .001). CONCLUSIONS: Subjects with lower levels of HDL have an increased risk to develop type 2 diabetes likely due to a greater ß-cell function decline over time.

Differences in insulin clearance between metabolically healthy and unhealthy obese subjects.

Metabolically healthy obese (MHO) are relatively insulin sensitive and have a favorable cardio-metabolic risk profile compared with metabolically abnormal obese (MAO). To evaluate whether MAO individuals have a decreased insulin clearance compared with MHO individuals, 49 MHO, 147 MAO, and 172 non-obese individuals were analyzed in this cross-sectional study. Insulin clearance and insulin sensitivity were assessed through euglycemic hyperinsulinemic clamp. MHO subjects exhibited significant lower triglycerides, total cholesterol, 2-h post-challenge glucose, fasting and 2-h post-challenge insulin, steady-state plasma insulin, alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase as compared with MAO individuals. Disposition index was higher in MHO subjects as compared with MAO individuals after adjusting for gender and age (P = 0.04). Insulin clearance was significantly lower in MAO individuals as compared with MHO and non-obese individuals. The difference between the two obese subgroups remained significant after adjusting for gender, age, waist circumference, fat mass, and insulin-stimulated glucose disposal (P = 0.03). The hepatic insulin extraction (C-peptide/insulin) in the fasting state was significantly higher in MHO subjects as compared with MAO individuals (P < 0.0001). In univariate analysis adjusted for gender and age, insulin clearance was correlated with hepatic insulin extraction (P = 0.01). In conclusion, insulin clearance differs among obese subjects with different metabolic phenotypes. Impaired insulin clearance may contribute to sustained fasting and post-meal hyperinsulinemia observed in MAO individuals.

Pioglitazone improves glucose metabolism and modulates skeletal muscle TIMP-3-TACE dyad in type 2 diabetes mellitus: a randomised, double-blind, placebo-controlled, mechanistic study.

AIMS/HYPOTHESIS: Pioglitazone (PIO) is a peroxisome proliferator-activated receptor (PPAR)γ agonist insulin-sensitiser with anti-inflammatory and anti-atherosclerotic effects. Our objective was to evaluate the effect of low-dose PIO (15 mg/day) on glucose metabolism and inflammatory state in obese individuals with type 2 diabetes. METHODS: A randomised, double-blind, placebo-controlled, mechanistic trial was conducted on 29 patients with type 2 diabetes treated with metformin and/or sulfonylurea. They were randomised to receive PIO or placebo (PLC) for 6 months, in a 1:1 ratio. Participants were allocated to interventions by central office. All study participants, investigators and personnel performing measurements were blinded to group assignment. At baseline and after 6 months patients underwent: (1) OGTT; (2) muscle biopsy to evaluate expression of TNF-α, tissue inhibitor of metalloproteases 3 (TIMP-3) levels, TNF-α converting enzyme (TACE) expression and enzymatic activity; (3) euglycaemic-hyperinsulinaemic clamp; (4) measurement of plasma high-sensitivity C-reactive protein (hsCRP), plasminogen activator inhibitor type-1 (PAI-1), TNF-α, IL-6, monocyte chemotactic protein-1 (MCP-1), adiponectin and fractalkine (FRK). The interventions were PIO 15 mg/day vs placebo and the main outcomes measured were absolute changes in whole-body insulin sensitivity, insulin secretion and inflammatory state. RESULTS: Fifteen participants were randomized to receive PIO and 14 participants were randomized to receive PLC. Eleven participants completed the study in the PIO group and nine participants completed the study in the PLC group and were analysed. Fasting plasma glucose and HbA1c decreased modestly (p < 0.05) after PIO and did not change after PLC. M/I (insulin-stimulated whole-body glucose disposal), adipose tissue insulin resistance (IR) index, insulin secretion/IR (disposition) index and insulinogenic index improved significantly after PIO, but not after PLC. Circulating MCP-1, IL-6, FRK, hsCRP and PAI-1 levels decreased in PIO- as compared with PLC-treated patients, while TNF-α did not change. TNF-α protein expression and TACE enzymatic activity in muscle were significantly reduced by PIO but not PLC. Adiponectin levels increased significantly after PIO as compared with PLC treatment. Given that the mean TACE enzymatic activity level at baseline in the PIO group was 0.29 ± 0.07 (fluorescence units [FU]), and at end of study decreased to 0.05 vs 0.14 in the PLC group, the power to reject the null hypothesis that the population means of the PIO and PLC groups are equal after 6 months is greater than 0.80. Given that M/I was 2.41 ± 0.35 µmol kg(-1) min(-1) (pmol/l)(-1) at baseline and increased by 0.55 in the PIO and 0.17 in the PLC groups, the power to reject the null hypothesis that the population means of the PIO and PLC groups are equal after 6 months is greater than 0.85. The type I error probability associated with this test of this null hypothesis is 0.05. No serious adverse events occurred in either group. CONCLUSIONS/INTERPRETATION: Low-dose PIO (15 mg/day) improves glycaemic control, beta cell function and inflammatory state in obese patients with type 2 diabetes. TRIAL REGISTRATION: Clinical.Trial.gov NCT01223196. FUNDING: This study was funded by TAKEDA.

Insulin clearance is associated with carotid artery intima-media thickness.

OBJECTIVE: The aim of this study was to investigate whether insulin clearance is independently associated with carotid artery intima-media thickness (IMT), a well-recognized index of vascular damage. METHODS: 361 Non-diabetic Caucasian subjects were subjected to euglycemic hyperinsulinemic clamp to assess insulin sensitivity, and insulin clearance. IMT of the common carotid was measured by ultrasonography. RESULTS: Among the study group, 270 subjects had normal glucose tolerance, 33 had impaired fasting glucose, and 58 had impaired glucose tolerance. Univariate correlations showed that age, BMI, waist, blood pressure, triglycerides, fasting and 2-h post-load glucose and insulin levels were positively correlated with carotid IMT whereas HDL, insulin clearance, and insulin-stimulated glucose disposal were negatively correlated with IMT. A multivariate regression analysis in a model including, in addition to insulin clearance, age, gender, BMI, waist, blood pressure, triglycerides, HDL, fasting and 2-h post-load glucose, insulin-stimulated glucose disposal, fasting and 2-h post-load insulin showed that the traits independently associated with carotid IMT were BMI (ß = 0.42, P < 0.0001), insulin clearance (ß = -0.29, P < 0.0001), age (ß = 0.19, P < 0.0001), waist (ß = 0.18, P = 0.01), diastolic blood pressure (ß = 0.17, P = 0.01), and 2-h post-load glucose (ß = 0.12, P = 0.03). These factors explained 26% of the variance in carotid IMT. Subjects in the lowest tertile of insulin clearance had a 4.06-fold higher odds of having vascular damage (IMT > 0.9 mm) as compared with those in the highest tertile (OR 4.06, 95%CI 1.15-13.24). CONCLUSIONS: Insulin clearance is independently associated with carotid IMT in adult non-diabetic subjects. Individuals with lower levels of insulin clearance have a higher odds of vascular damage.