Is common genetic variation at IRS1, ENPP1 and TRIB3 loci associated with cardiometabolic phenotypes in type 2 diabetes? An exploratory analysis of the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS) 5

Insulin resistance and beta-cell dysfunction in newly diagnosed type 2 diabetes: Expression, aggregation and predominance. Verona Newly Diagnosed Type 2 Diabetes Study 10

AIMS

We investigated quantitative expression, mutual aggregation and relation with hyperglycemia of insulin resistance (IR) and beta-cell dysfunction (BCD) in newly diagnosed type 2 diabetes.

METHODS

We assessed IR with euglycemic hyperinsulinemic clamp and BCD with modelled glucose/C-peptide response to oral glucose in 729 mostly drug-naïve patients. We measured glycated hemoglobin, pre-prandial, post-prandial and meal-related excursion of blood glucose.

RESULTS

IR was found in 87.8% [95% confidence intervals 85.4-90.2] and BCD in 90.0% [87.8-92.2] of subjects, ranging from mild to moderate or severe. Approximately 20% of subjects had solely one defect: BCD 10.8% [8.6-13.1] or IR 8.6% [6.6-10.7]. Insulin resistance and BCD aggregated in most subjects (79.1% [76.2-82.1]). We arbitrarily set nine possible combinations of mild, moderate or severe IR and mild, moderate or severe BCD, finding that each had a similar frequency (∼10%). In multiple regression analyses parameters of glucose control were related more strongly with BCD than with IR.

CONCLUSIONS

In newly-diagnosed type 2 diabetes, IR and BCD are very common with a wide range of expression but no specific pattern of aggregation. Beta-cell dysfunction is likely to play a greater quantitative role than IR in causing/sustaining hyperglycemia in newly-diagnosed type 2 diabetes.

Chronic complications in patients with newly diagnosed type 2 diabetes: prevalence and related metabolic and clinical features: the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS) 9

INTRODUCTION

We explored the presence of chronic complications in subjects with newly diagnosed type 2 diabetes referred to the Verona Diabetes Clinic. Metabolic (insulin secretion and sensitivity) and clinical features associated with complications were also investigated.

RESEARCH DESIGN AND METHODS

The comprehensive assessment of microvascular and macrovascular complications included detailed medical history, resting ECG, ultrasonography of carotid and lower limb arteries, quantitative neurological evaluation, cardiovascular autonomic tests, ophthalmoscopy, kidney function tests. Insulin sensitivity and beta-cell function were assessed by state-of-the-art techniques (insulin clamp and mathematical modeling of glucose/C-peptide curves during oral glucose tolerance test).

RESULTS

We examined 806 patients (median age years, two-thirds males), of whom prior clinical cardiovascular disease (CVD) was revealed in 11.2% and preclinical CVD in 7.7%. Somatic neuropathy was found in 21.2% and cardiovascular autonomic neuropathy in 18.6%. Retinopathy was observed in 4.9% (background 4.2%, proliferative 0.7%). Chronic kidney disease (estimated glomerular filtration rate <60 mL/min/1.73 m²) was found in 8.8% and excessive albuminuria in 13.2% (microalbuminuria 11.9%, macroalbuminuria 1.3%).Isolated microvascular disease occurred in 30.8%, isolated macrovascular disease in 9.3%, a combination of both in 9.1%, any complication in 49.2% and no complications in 50.8%.Gender, age, body mass index, smoking, hemoglobin A1c and/or hypertension were independently associated with one or more complications. Insulin resistance and beta-cell dysfunction were associated with macrovascular but not microvascular disease.

CONCLUSIONS

Despite a generally earlier diagnosis for an increased awareness of the disease, as many as ~50% of patients with newly diagnosed type 2 diabetes had clinical or preclinical manifestations of microvascular and/or macrovascular disease. Insulin resistance might play an independent role in macrovascular disease.

TRIAL REGISTRATION NUMBER

NCT01526720.

Association of IRS1 genetic variants with glucose control and insulin resistance in type 2 diabetic patients from Bosnia and Herzegovina

Background Previous studies reported conflicting results regarding association of insulin receptor substrate 1 (IRS1) gene variation with type 2 diabetes (T2D) and insulin resistance (IR) in different ethnic groups. We examined the association of rs7578326, rs2943641, and rs4675095 in the IRS1 gene with T2D and related traits in a population from Bosnia and Herzegovina, which is one of the European countries with the highest T2D prevalence of 12.5%. Methods Our study included 390 T2D patients and 252 control subjects. Biochemical parameters, including fasting glucose (FG), fasting insulin (FI), homeostasis model assessment insulin resistance index (HOMA-IR), and HbA1c were measured in all participants. Genotyping analysis was performed by Mass Array Sequenom iPlex platform. Results Our results demonstrated that rs7578326 and rs4675095 variants were associated with increased FG levels. The rs7578326 was also associated with higher FI, HOMA-IR (B = 0.08, 95% CI [0.01, 0.15], padd = 0.025; B = 0.079, 95% CI [0.006, 0.150], padd = 0.033, respectively) in T2D, and with HbA1c (B = 0.034, 95% CI [0.003, 0.065], pdom = 0.035) in non-drug-treated T2D. In contrast, rs2943641 C allele was associated with lower FG levels in control subjects (B = -0.17, 95% CI [-0.03, -0.002], padd = 0.030) and HbA1c (B = 0.03, 95% CI [0.002, 0.06], pdom = 0.040) in non-drug-treated T2D. Conclusions We report the association between common variants in IRS1 gene with insulin resistance, glucose, and HbA1c levels in Bosnia and Herzegovina's population.

A renal genetic risk score (GRS) is associated with kidney dysfunction in people with type 2 diabetes

This study aims to investigate whether renal and cardiovascular phenotypes in Italian patients with type 2 diabetes (T2D) could be influenced by a number of disease risk SNPs recently found in genome-wide association studies (GWAS). In 1591 Italian subjects with T2D: (1) 47 SNPs associated to kidney function and/or chronic kidney disease (CKD) and 49 SNPs associated to cardiovascular disease (CVD) risk were genotyped; (2) urinary albumin/creatinine (A/C) ratio, glomerular filtration rate (eGFR) and lipid profile were assessed; (3) a standard electrocardiogram was performed; (4) two genotype risk scores (GRS) were computed (a renal GRS calculated selecting 39 SNPs associated with intermediate traits of kidney damage and a cardiovascular GRS determined selecting 42 SNPs associated to CVD risk phenotypes). After correction for multiple comparisons, the renal GRS was not associated to A/C ratio (p = 0.33), but it was significantly related to decreased eGFR (p = 0.005). No association between the cardiovascular GRS and electrocardiogram was detected. Thus, in Italian patients with T2D a renal GRS might predict the decline in glomerular function, suggesting that the clock of diabetes associated CKD starts ticking long before hyperglycemia. Our data support the feasibility of gene-based prediction of complications in people with T2D.

Assessment of Human Tribbles Homolog 3 Genetic Variation (rs2295490) Effects on Type 2 Diabetes Patients with Glucose Control and Blood Pressure Lowering Treatment

Effects of human tribbles homolog 3 (TRIB3) genetic variation (c.251 A>G, Gln84Arg, rs2295490) on the clinical outcomes of vascular events has not been evaluated in patients with type 2 diabetes after blood pressure lowering and glucose controlling treatment. We did an analysis of a 2×2 factorial (glucose control axis and blood pressure lowering axis) randomized controlled clinical trial at 61 centers in China, with a follow-up period of 5years. The major vascular endpoints were the composites of death from cardio-cerebral vascular diseases, non-fatal stroke and myocardial infraction, new or worsening renal and diabetic eye disease. A total of 1884 participants were included in our research with a 4.8years median follow-up. For glucose lowering axis, patients with TRIB3 (rs2295490) AA (n=609) genotype exhibited significantly reduced risk of major vascular events compared with AG+GG (n=335) genotype carriers (Hazard ratio 0.72, 95% CI 0.55-0.94, p=0.016), Paradoxically, the risk of vascular events were significantly increased in patients with AA (n=621) compared to AG+GG (n=319) genotype for intensive glucose control (Hazard ratio 1.46, 95% CI, 1.06–2.17, p = 0.018) [corrected]. . For blood pressure lowering axis, marginally significant difference was found between TRIB3 variant and coronary events. Our findings suggest that good glucose and blood pressure control exhibited greater benefits on vascular outcomes in patients with TRIB3 (rs2295490) G allele.