Elisabetta Mandosi

Chronic Inhibition of cGMP Phosphodiesterase 5A Improves Diabetic Cardiomyopathy A Randomized, Controlled Clinical Trial Using Magnetic Resonance Imaging With Myocardial Tagging

Background— cGMP phosphodiesterase type 5 protein is upregulated in myocardial hypertrophy. However, it has never been ascertained whether phosphodiesterase type 5 inhibition exerts an antiremodeling effect in nonischemic heart disease in humans. We explored the cardioreparative properties of a selective phosphodiesterase type 5 inhibitor, sildenafil, in a model of diabetic cardiomyopathy. Methods and Results— Fifty-nine diabetic men (60.3±7.4 years) with cardiac magnetic resonance imaging consistent with nonischemic, nonfailing diabetic cardiomyopathy (reduced circumferential strain [&sgr;], −12.6±3.1; increased left ventricular [LV] torsion [&thgr;], 18.4±4.6°; and increased ratio of LV mass to volume, 2.1±0.5 g/mL) were randomized to receive sildenafil or placebo (100 mg/d). At baseline, the metabolic indices were correlated with torsion, strain, N-terminal pro–B-type natriuretic peptide, vascular endothelial growth factor, monocyte chemotactic protein-1, and blood pressure. After 3 months, sildenafil produced a significant improvement compared with placebo in LV torsion (&Dgr;&thgr;: sildenafil, −3.89±3.11° versus placebo, 2.13±2.35°; P<0.001) and strain (&Dgr;&sgr;: sildenafil, −3.30±1.86 versus placebo, 1.22±1.84; P<0.001). Sildenafil-induced improvement of LV contraction was accompanied by consistent changes in chamber geometry and performance, with a 6.5±11 improvement in mass-to-volume ratio over placebo (P=0.021). Monocyte chemotactic protein-1 and transforming growth factor-&bgr; were the only markers affected by active treatment (&Dgr;monocyte chemotactic protein-1: −75.30±159.28 pg/mL, P=0.032; &Dgr;transforming growth factor-&bgr;: 5.26±9.67 ng/mL, P=0.009). No changes were found in endothelial function, afterload, or metabolism. Conclusions— The early features of diabetic cardiomyopathy are LV concentric hypertrophy associated with altered myocardial contraction dynamics. Chronic phosphodiesterase type 5 inhibition, at this stage, has an antiremodeling effect, resulting in improved cardiac kinetics and circulating markers. This effect is independent of any other vasodilatory or endothelial effects and is apparently exerted through a direct intramyocardial action. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00692237.

Poor Glycemic Control Is an Independent Risk Factor for Low HDL Cholesterol in Patients With Type 2 Diabetes

OBJECTIVE To determine whether the association observed between poor glycemic control and low HDL cholesterol in type 2 diabetes is dependent on obesity and/or hypertriglyceridemia. RESEARCH DESIGN AND METHODS We performed a cross-sectional study of 1,819 patients with type 2 diabetes and triglycerides <400 mg/dl enrolled at three diabetes centers in Italy. The risk for low HDL cholesterol was analyzed as a function of A1C levels. Odds ratios (ORs) were calculated after adjustment for confounding factors. RESULTS A 1% increase in A1C significantly increased the risk for low HDL cholesterol (OR 1.17 [95% CI 1.1–1.2], P = 0.00072); no changes were observed when age, sex, smoking, and lipid-lowering therapy were included in the model (1.17 [1.1–1.2], P = 0.00044). The association remained strong after adjustments for obesity and hypertriglyceridemia in multivariate analysis (1.12 [1.05–1.18], P = 0.00017). CONCLUSIONS Poor glycemic control appears to be an independent risk factor for low HDL cholesterol in type 2 diabetes.

Endothelial dysfunction markers as a therapeutic target for Sildenafil treatment and effects on metabolic control in type 2 diabetes

Objective: Endothelial dysfunction (ED) plays a role in diabetic cardiovascular complications. Hyperglycemia increases cytockines involved in vascular inflammation. Inhibition of phosphodiesterase type 5 (PDE5) exerts a relaxation on corpora cavernosa and has cardioprotective properties. The effect of chronic sildenafil treatment, on ED markers and metabolic parameters in a non-randomized study on men with type 2 diabetes (T2DM), was investigated. Research design and methods: Twenty-eight T2DM patients (61.2 ± 7.8 years, hemoglobin A1c (HbA1c) 7.9 ± 1.3%, duration of diabetes 11.5 ± 7.8 years) were treated with sildenafil 100 mg/d for 3 months. Baseline and postprandial glycemia, insulin, HbA1c, HOMA index, lipids, glomerular filtration rate, homocysteine were assessed at each visit. P-selectin (CD62P), CD14/42b, CD14/41, ICAM (CD54), PECAM (CD31) and CD11b/CD18, were evaluated, after monocyte isolation with flow-cytometry, before and after treatment. Results: After 3 months, sildenafil decreased P-selectin (p < 0.05), post-prandial glycemia (p < 0.01), HbA1c (p < 0.01), low-density lipoprotein cholesterol (p < 0.01) and increased high-density lipoprotein (p < 0.05). Conclusions: PDE5 inhibition, in T2DM patients, reduces the endothelial function marker P-selectin and exerts a beneficial effect on glycometabolic control.

Effect of insulin on airway responsiveness in patients with type 2 diabetes mellitus: a cohort study.

Background. The correlation between low insulin levels and a decreased sensitivity of the muscarinic receptor has been shown on induced-diabetes animal models. We designed a cohort study with the aim of evaluating the effects of insulin therapy on airway responsiveness (AR) in human patients with type 2 diabetes mellitus. Methods. We enrolled 92 patients with type 2 diabetes who had switched from oral anti-diabetic therapy to treatment by insulin subcutaneous injection. Patients were administered the methacholine challenge test (MCT) at time 0 (pre-insulin therapy) and at intervals of 15, 30, 90, 180, and 360 days after insulin treatment. The decline of forced expiratory volume in 1 second (FEV1)% from baseline (Δ FEV1) in response to inhaled methacholine (MCH) was determined to assess airway hyper-responsiveness (AHR). Results. A total of 81 patients (18 women and 63 men) completed the study. Their mean age was 58 ± 7 years and the mean duration of disease was 13.5 ± 7.7 years. The mean decrease of FEV1 at pre-insulin assessment was 2.96 ± 2.6%. Compared with the pre-insulin value, a significant increase of Δ FEV1 was observed at 15, 30, and 90 days after treatment (6.25%, CI 95% 5.4 to 7.2, p = 0.0005; 7.64%, CI 95% 6.6 to 8.1, p < 0.001; 6.45%, CI 95% 5.5 to 7.3, p = 0.0004, respectively), while after 180 and 360 days AR was similar to pre-insulin values (Δ FEV1, 3.62%, CI 95% 2.7 to 3.5 and 3.11%, CI 95% 7.9 to 9.3, respectively). Conclusions. The finding of an increased AR in patients with type 2 diabetes during the first 3 months of insulin therapy may underline the importance of monitoring pulmonary function and respiratory symptoms in patients switching from oral anti-diabetic drugs to insulin therapy, especially in the subset of individuals with respiratory disorders.

Metabolic Syndrome Is not a Risk Factor for Kidney Dysfunction in Obese Non-diabetic Subjects

Objective: To investigate whether insulin resistance (IR) and the metabolic syndrome (MS) are associated with kidney dysfunction in obese non‐diabetic (OND) subjects.

Poly(ADP-ribose)polymerase activity is reduced in circulating mononuclear cells from type 2 diabetic patients†

Poly(ADP‐ribose)polymerase (PARP‐1), a nuclear enzyme activated by DNA strand breaks, is involved in DNA repair, aging, inflammation, and neoplastic transformation. In diabetes, reactive oxygen and nitrogen species occurring in response to hyperglycemia cause DNA damages and PARP‐1 activation. Because circulating mononuclear cells (MNCs) are involved in inflammation mechanisms, these cells were chosen as the experimental model to evaluate PARP‐1 levels and activity in patients with type 2 diabetes. MNCs were isolated from 25 diabetic patients (18 M, 7 F, age, 63.5 ± 10.2 years, disease duration 17.7 ± 8.2 years) and 11 age and sex matched healthy controls. PARP‐1 expression and activity were analyzed by semi‐quantitative PCR, Western and activity blot, and immunofluorescence microscopy. PARP‐1‐mRNA expression was increased in MNCs from all diabetic patients versus controls (P < 0.01), whereas PARP‐1 content and activity were significantly lower in diabetic patients (P < 0.0001). To verify whether low PARP‐1 levels and activity were due to a proteolytic effect of caspase‐3 like, the latter activation was measured by a fluorimetric assay. Caspase‐3 activity in MNCs was significantly higher in diabetic patients versus control subjects (P < 0.0001). The different PARP‐1 behavior in MNCs from patients with type 2 diabetes could therefore be responsible for the abnormal inflammation and infection responses in diabetes.

Lack of the QTc physiologic decrease during cardiac stress test in patients with type 2 diabetes treated with secretagogues

Patients with type 2 diabetes are at increased susceptibility to a prolonged QT interval. Furthermore, insulin secretagogues, drugs used to treat diabetes, may prolong QT interval and provoke arrhythmias. We evaluated whether secretagogues can affect QTc interval during cardiac stress test in 20 patients with type 2 diabetes treated with secretagogues. ECG stress test was performed in all patients. QTc interval was calculated both before cardiac stress test (BCST) and at acme of cardiac stress test (ACST). Diabetic patients treated with secretagogues showed longer QTc-ACST values than those treated with metformin only. QTc-ACST values resulted shorter than QTc-BCST values in control group. Diabetic patients treated with secretagogues showed QTc-ACST values significantly longer than QTc-BCST values. In our study, diabetic patients treated with secretagogues did not show the QTc physiologic decrease that is a protective against arrhythmias. These results suggest to evaluate, in these patients, QT length, even during routine cardiac stress test.

Waist circumference reduction after insulin detemir therapy in type 2 diabetes patients previously treated with NPH

We studied the weight-sparing effect and treatment satisfaction when switching from NPH to insulin detemir in type 2 diabetes. Mean HbA(1c) (P<0.05) and waist circumference (P<0.05) were reduced while treatment satisfaction improved (P<0.03). No weight gain was observed. Detemir improves glycemic control, treatment satisfaction, and may provide additional weight-sparing benefits.

Could gestational diabetes mellitus be managed through dietary bioactive compounds? Current knowledge and future perspectives

Gestational diabetes mellitus (GDM) is a serious problem growing worldwide that needs to be addressed with urgency in consideration of the resulting severe complications for both mother and fetus. Growing evidence indicates that a healthy diet rich in fruit, vegetables, nuts, extra-virgin olive oil and fish has beneficial effects in both the prevention and management of several human diseases and metabolic disorders. In this review, we discuss the latest data concerning the effects of dietary bioactive compounds such as polyphenols and PUFA on the molecular mechanisms regulating glucose homoeostasis. Several studies, mostly based on in vitro and animal models, indicate that dietary polyphenols, mainly flavonoids, positively modulate the insulin signalling pathway by attenuating hyperglycaemia and insulin resistance, reducing inflammatory adipokines, and modifying microRNA (miRNA) profiles. Very few data about the influence of dietary exposure on GDM outcomes are available, although this approach deserves careful consideration. Further investigation, which includes exploring the ‘omics’ world, is needed to better understand the complex interaction between dietary compounds and GDM.