Pasquale Paolisso

Sirtuin 6 Expression and Inflammatory Activity in Diabetic Atherosclerotic Plaques: Effects of Incretin Treatment

The role of sirtuin 6 (SIRT6) in atherosclerotic progression of diabetic patients is unknown. We evaluated SIRT6 expression and the effect of incretin-based therapies in carotid plaques of asymptomatic diabetic and nondiabetic patients. Plaques were obtained from 52 type 2 diabetic and 30 nondiabetic patients undergoing carotid endarterectomy. Twenty-two diabetic patients were treated with drugs that work on the incretin system, GLP-1 receptor agonists, and dipeptidyl peptidase-4 inhibitors for 26 ± 8 months before undergoing the endarterectomy. Compared with nondiabetic plaques, diabetic plaques had more inflammation and oxidative stress, along with a lesser SIRT6 expression and collagen content. Compared with non-GLP-1 therapy–treated plaques, GLP-1 therapy–treated plaques presented greater SIRT6 expression and collagen content, and less inflammation and oxidative stress, indicating a more stable plaque phenotype. These results were supported by in vitro observations on endothelial progenitor cells (EPCs) and endothelial cells (ECs). Indeed, both EPCs and ECs treated with high glucose (25 mmol/L) in the presence of GLP-1 (100 nmol/L liraglutide) presented a greater SIRT6 and lower nuclear factor-κB expression compared with cells treated only with high glucose. These findings establish the involvement of SIRT6 in the inflammatory pathways of diabetic atherosclerotic lesions and suggest its possible positive modulation by incretin, the effect of which is associated with morphological and compositional characteristics of a potential stable plaque phenotype.

Poor glycaemic control in type 2 diabetes patients reduces endothelial progenitor cell number by influencing SIRT1 signalling via platelet-activating factor receptor activation

Aims/hypothesisDownregulation of levels of endothelial progenitor cells (EPCs) during in-vitro short-term exposure to high glucose concentrations relates to reduced activity of silent information regulator 1 (SIRT1) and increased synthesis of platelet-activating factor (PAF). We investigated the possible relationship between PAF and SIRT1 pathways in EPCs during altered glucose homeostasis.MethodsSIRT1 and PAF receptor (PAF-R) levels were determined by western blot, RT-PCR and confocal laser-scanning microscopy. In-vivo experiments were performed on 48 type 2 diabetic patients (25 with poor glycaemic control and 23 with good glycaemic control) and 20 control individuals. In-vitro experiments with the PAF-R antagonist CV3988 were performed on EPCs isolated from leucocyte-rich buffy coat of healthy human donors.ResultsDecreased SIRT1 protein levels were observed in EPCs from type 2 diabetic patients compared with control individuals (p < 0.01). Notably, the SIRT1 level was consistently lower in patients with poor glycaemic control than in those with good glycaemic control (p < 0.01). Diabetic patients also showed an upregulation of PAF-Rs; this response occurred to a greater extent in individuals with poor glycaemic control than in those with good glycaemic control. In-vitro experiments confirmed that EPCs respond to PAF stimulation with decreased SIRT1 protein and SIRT1 mRNA levels. Moreover, reduction of SIRT1 levels and activity were abolished by CV3988.Conclusions/interpretationThese findings unveil a link between PAF and SIRT1 pathways in EPCs that contributes to the deleterious effect of hyperglycaemia on the functional properties of EPCs, crucial in diabetes and peripheral vascular complications.

Metabolic syndrome is associated with a poor outcome in patients affected by outflow tract premature ventricular contractions treated by catheter ablation

BackgroundThe purpose of this study was to investigate the impact of metabolic syndrome (MS) on outcome of catheter ablation (CA) for treatment of frequent premature ventricular contraction beats (PVCs) originating from right ventricular outflow tract (RVOT), left ventricular outflow tract (LVOT) or coronary cusps (CUSPs), in patients with normal ventricular systolic function and absence of cardiac structural disease.MethodsIn this multicentre prospective study we evaluated 90 patients with frequent PVCs originating from RVOT (n = 68), LVOT (n = 19) or CUSPs (n = 3), treated with CA. According to baseline diagnosis they were divided in patients with MS (n = 24) or without MS (n = 66). The study endpoint was a composite of recurrence of acute or delayed outflow tract ventricular arrhythmia: acute spontaneous or inducible outflow tract ventricular arrhythmia recurrence or recurrence of outflow tract PVCs in holter monitoring at follow up.ResultsPatients with MS compared to patients without MS showed a higher acute post-procedural recurrence of outflow tract PVCs (n = 8, 66.6%, vs. n = 6, 9.0%, p = 0.005). At a mean follow up of 35 (17-43) months survival free of recurrence of outflow tract PVCs was lower in patients with baseline MS compared to patients without MS diagnosis (log-rank test, p < 0.001). In cox regression analysis, only MS was independently associated with study endpoint (HR = 9.655 , 95% CI 3.000-31.0.68 , p < 0.001).ConclusionsMS is associated with a higher recurrence rate of outflow tract PVCs after CA in patients without structural heart disease.

Dipeptidyl Peptidase 4 Inhibition May Facilitate Healing of Chronic Foot Ulcers in Patients with Type 2 Diabetes

The pathophysiology of chronic diabetic ulcers is complex and still incompletely understood, both micro- and macroangiopathy strongly contribute to the development and delayed healing of diabetic wounds, through an impaired tissue feeding and response to ischemia. With adequate treatment, some ulcers may last only weeks; however, many ulcers are difficult to treat and may last months, in certain cases years; 19–35% of ulcers are reported as nonhealing. As no efficient therapy is available, it is a high priority to develop new strategies for treatment of this devastating complication. Because experimental and pathological studies suggest that incretin hormone glucagon-like peptide-1 may improves VEGF generation and promote the upregulation of HIF-1α through a reduction of oxidative stress, the study evaluated the effect of the augmentation of GLP-1, by inhibitors of the dipeptidyl peptidase-4, such as vildagliptin, on angiogenesis process and wound healing in diabetic chronic ulcers. Although elucidation of the pathophysiologic importance of these aspects awaits further confirmations, the present study evidences an additional aspect of how DPP-4 inhibition might contribute to improved ulcer outcome.

Autonomic dysfunction is associated with brief episodes of atrial fibrillation in type 2 diabetes.

BACKGROUND AND AIMS This study aimed to investigate the relationship between asymptomatic episodes of atrial fibrillation (AF) and abnormalities of the autonomic nervous system in type 2 diabetic patients who did not have evidence of atrial fibrillation at baseline. METHODS AND RESULTS In a multicentric cross-sectional controlled study, 1992 patients with type 2 diabetes were screened. All underwent ambulatory ECG recording for 48-hour at 3, 6, 9, and 12months. Heart rate variability (HRV) was used as indicator of autonomic activity. One hundred seventy-six diabetics with silent atrial fibrillation episodes (SAFE group) and 288 without silent atrial fibrillation (non-SAFE group) were enrolled. These selected diabetics were matched on clinical and anthropometric data to 120 control subjects without diabetes of the control group. HRV analysis evidenced that LF/HF ratio was significantly higher in the SAFE group than in the non-SAFE group (P<0.05) in the whole period of HM analysis. AF absolute burdens were positively correlated with LF/HF ratio (r=0.31, P<0.001). Multiple regression analysis showed that LF/HF ratio was an independent determinant of AF episodes. CONCLUSIONS This study originally showed a strong relationship between autonomic dysfunction and silent atrial fibrillation in type 2 diabetes.

Effects of α-lipoic acid therapy on sympathetic heart innervation in patients with previous experience of transient takotsubo cardiomyopathy.

BACKGROUND Takotsubo syndrome is a stress cardiomyopathy, characterized by reversible left ventricle (LV) apical ballooning in the absence of significant angiographic coronary artery stenosis. The frequent association with emotional stress suggests in this disease an autonomic nervous system involvement. We could think that a therapeutic treatment targeting heart sympathetic dysfunction could be of crucial importance. METHODS From January 2010 to June 2012, 886 patients were consecutively evaluated at Cardarelli Hospital, Naples, Italy. Among these, 48 patients met takotsubo cardiomyopathy (TCM) criteria. Each patient was assessed with history and physical examination, 12-lead electrocardiogram, serum troponin, coronary arteriography, and left ventricular angiogram, perfusion myocardial scintigraphy with technetium 99m, with echocardiography and 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy. At discharge, the surviving patients were randomly assigned to α-lipoic acid (ALA) treatment (600mg once daily) or placebo. Following discharge, after the initial TCM event, patients returned to our outpatient clinic at Internal Medicine of the Second University Naples for the follow-up evaluation quarterly until 12 months. Routine analysis, myocardial damage serum markers, oxidative stress serum markers, pro-inflammatory cytokines, and sympathetic tone activity were evaluated in all patients. RESULTS ALA administration improved MIBG defect size at 12 months compared to placebo. CONCLUSIONS Adrenergic cardiac innervation dysfunction in TCM patients persists after previous experience of transient stress-induced cardiac dysfunction. ALA treatment improves the adrenergic cardiac innervation. This study evaluates whether sympatho-vagal alterations are TCM event-related.

Peri-procedural tight glycemic control during early percutaneous coronary intervention is associated with a lower rate of in-stent restenosis in patients with acute ST-elevation myocardial infarction.

OBJECTIVE We examined the effects of peri-procedural intensive glycemic control (IGC) during early percutaneous coronary intervention (PCI) on restenosis rate in hyperglycemic patients with ST-segment elevation myocardial infarction (STEMI). RESEARCH DESIGN AND METHODS A total of 165 hyperglycemic patients (glucose ≥ 140 mg/dl) with first STEMI undergoing PCI were studied. Patients were randomized to IGC for almost 24 h after PCI (n = 82; glucose, 80-140 mg/dl) followed by multidose sc insulin during the hospital stay or conventional glycemic control (CGC; n = 83; glucose, 180-200 mg/dl) followed by conventional therapy. Coronary angiography was performed at study entry and at 6-month follow-up. Blood samples for glycemia, hemoglobin A1c, inflammatory markers (C-reactive protein and TNF-α), monocyte chemoattractant-protein-1, and oxidative stress (nitrotyrosine) were collected immediately before and 24 h, 30 and 180 d after PCI. RESULTS After insulin infusion, mean plasma glucose during the peri-procedural period was greater in the CGC group than in the IGC group (CGC, 191 ± 15 mg/dl; IGC, 145 ± 35 mg/dl; P < 0.001). After the insulin infusion period, the levels of markers of oxidative stress (nitrotyrosine), inflammation (C-reactive protein, TNF-α), and monocyte chemoattractant-protein-1 were significantly higher in CGC patients compared with IGC patients. Moreover, ICG during PCI reduces restenosis by half (48 and 24%) at 6 months. During follow-up, there was no difference in mortality rates, glucose, inflammatory and oxidative stress markers among the groups. In-stent restenosis was positively associated with mean plasma glucose levels as well as oxidative stress and inflammatory markers during the insulin infusion period. CONCLUSIONS In hyperglycemic patients with STEMI, optimal peri-procedural glycemic control by reducing oxidative stress and inflammation may improve the outcome after PCI.

Peri-procedural tight glycemic control during early percutaneous coronary intervention up-regulates endothelial progenitor cell level and differentiation during acute ST-elevation myocardial infarction: effects on myocardial salvage.

BACKGROUND We examined the effects of peri-procedural intensive glycemic control during early percutaneous coronary intervention (PCI) on the number and differentiation of endothelial progenitor cells (EPCs) and myocardial salvage (MS) in hyperglycemic patients with first ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS We conducted a randomized, prospective, open label study on 194 patients with STEMI undergoing PCI: 88 normoglycemic patients (glucose < 140 mg/dl) served as the control group. Hyperglycemic patients (glucose ≥140 mg/dl) were randomized to intensive glycemic control (IGC) for almost 24 h after PCI (n = 54; 80-140 mg/dl) or conventional glycemic control (CGC, n = 52; 180-200 mg/dl). EPC number, differentiation, and SIRT1expression were assessed immediately before, 24 h, 7, 30 and 180 days after PCI. The primary end point of the study was salvage index, measured as the proportion of initial perfusion defect (acute technetium-99m sestamibi scintigraphy, performed 5 to 7 days after STEMI) and myocardium salvaged by therapy (6 months after STEMI). Hyperglycemic patients had lower EPC number and differentiation and lower SIRT1 levels than normoglycemic patients (P < 0.01). After the insulin infusion, mean plasma glucose during peri-procedural period was greater in CGC group than in IGC group (P < 0.001). The EPC number, their capability to differentiate, and SIRT1 levels were significantly higher in IGC group than in CGC, peaking after 24 h (P < 0.01). In the IGC group, the salvage index was greater than in patients treated with CGC (P < 0.001). CONCLUSIONS Optimal peri-procedural glycemic control, by increasing EPC number and their capability to differentiate, may improve the myocardial salvage.

Effects of Alpha Lipoic Acid on Multiple Cytokines and Biomarkers and Recurrence of Atrial Fibrillation Within 1 Year of Catheter Ablation

Catheter ablation (CA) is a procedure commonly used to restore sinus rhythm in patients with atrial fibrillation (AF). However, AF recurrence after CA remains a relevant clinical issue. We tested the effects of an oral antioxidant treatment (alpha lipoic acid [ALA]) on AF recurrence post-CA. Patients with paroxysmal AF have been enrolled in a randomized, prospective, double-blind, controlled placebo trial. After CA, patients have been randomly assigned to receive ALA oral supplementation (ALA group) or placebo (control group) and evaluated at baseline and after a 12-month follow-up: 73 patients completed the 12-month follow-up (ALA: 33 and control: 40). No significant difference has been detected between the 2 groups at baseline. Strikingly, 1 year after CA, ALA therapy significantly reduced serum markers of inflammation. However, there was no significant difference in AF recurrence events at follow-up comparing ALA with placebo group. Multivariate analysis revealed that the only independent prognostic risk factor for AF recurrence after CA is age. In conclusion, ALA therapy reduces serum levels of common markers of inflammation in ablated patients. Nevertheless, ALA does not prevent AF recurrence after an ablative treatment.

Cardiac Resynchronization Therapy Outcomes in Type 2 Diabetic Patients: Role of MicroRNA Changes

Heart failure (HF) and type 2 diabetes mellitus (T2DM) are two growing and related diseases in general population and particularly in elderly people. In selected patients affected by HF and severe dysfunction of left ventricle ejection fraction (LVEF), with left bundle brunch block, the cardiac resynchronization therapy with a defibrillator (CRT) is the treatment of choice to improve symptoms, NYHA class, and quality of life. CRT effects are related to alterations in genes and microRNAs (miRs) expression, which regulate cardiac processes involved in cardiac apoptosis, cardiac fibrosis, cardiac hypertrophy and angiogenesis, and membrane channel ionic currents. Different studies have shown a different prognosis in T2DM patients and T2DM elderly patients treated by CRT-D. We reviewed the literature data on CRT-D effect on adult and elderly patients with T2DM as compared with nondiabetic patients.