Carbonic anhydrase activation is associated with worsened pathological remodeling in human ischemic diabetic cardiomyopathy.

BACKGROUND: Diabetes mellitus (DM) has multifactorial detrimental effects on myocardial tissue. Recently, carbonic anhydrases (CAs) have been shown to play a major role in diabetic microangiopathy but their role in the diabetic cardiomyopathy is still unknown. METHODS AND RESULTS: We obtained left ventricular samples from patients with DM type 2 (DM-T2) and nondiabetic (NDM) patients with postinfarct heart failure who were undergoing surgical coronary revascularization. Myocardial levels of CA-I and CA-II were 6- and 11-fold higher, respectively, in DM-T2 versus NDM patients. Elevated CA-I expression was mainly localized in the cardiac interstitium and endothelial cells. CA-I induced by high glucose levels hampers endothelial cell permeability and determines endothelial cell apoptosis in vitro. Accordingly, capillary density was significantly lower in the DM-T2 myocardial samples (mean±SE=2152±146 versus 4545±211/mm(2)). On the other hand, CA-II was mainly upregulated in cardiomyocytes. The latter was associated with sodium-hydrogen exchanger-1 hyperphosphorylation, exaggerated myocyte hypertrophy (cross-sectional area 565±34 versus 412±27 μm(2)), and apoptotic death (830±54 versus 470±34 per 10(6) myocytes) in DM-T2 versus NDM patients. CA-II is activated by high glucose levels and directly induces cardiomyocyte hypertrophy and death in vitro, which are prevented by sodium-hydrogen exchanger-1 inhibition. CA-II was shown to be a direct target for repression by microRNA-23b, which was downregulated in myocardial samples from DM-T2 patients. MicroRNA-23b is regulated by p38 mitogen-activated protein kinase, and it modulates high-glucose CA-II-dependent effects on cardiomyocyte survival in vitro. CONCLUSIONS: Myocardial CA activation is significantly elevated in human diabetic ischemic cardiomyopathy. These data may open new avenues for targeted treatment of diabetic heart failure

Moderate-intensity statin therapy seems ineffective in primary cardiovascular prevention in patients with type 2 diabetes complicated by nephropathy:a multicenter prospective 8 years follow up study

Background: Although numerous studies and metanalysis have shown the beneficial effect of statin therapy in CVD secondary prevention, there is still controversy such the use of statins for primary CVD prevention in patients with DM. The purpose of this study was to evaluate the occurrence of total major adverse cardio-vascular events (MACE) in a cohort of patients with type 2 diabetes complicated by nephropathy treated with statins, in order to verify real life effect of statin on CVD primary prevention. Methods: We conducted an observational prospective multicenter study on 564 patients with type 2 diabetic nephropathy free of cardiovascular disease attending 21 national outpatient diabetes clinics and followed them up for 8 years. 169 of them were treated with statins (group A) while 395 were not on statins (group B). Results: Notably, none of the patients was treated with a high-intensity statin therapy according to last ADA position statement. Total MACE occurred in 32 patients from group A and in 68 patients from group B. Fatal MACE occurred in 13 patients from group A and in 30 from group B; nonfatal MACE occurred in 19 patients from group A and in 38 patients from group B. The analysis of the Kaplan-Meier survival curves showed a not statistically significant difference in the incidence of total (p 0.758), fatal (p 0.474) and nonfatal (p 0.812) MACE between the two groups. HbA1c only showed a significant difference in the incidence of MACE between the two groups (HR 1.201, CI 1.041-1.387, p 0.012). Conclusions: These findings suggest that, in a real clinical setting, moderate-intensity statin treatment is ineffective in cardiovascular primary prevention for patients with diabetic nephropathy

The impact of glucose-insulin-potassium infusion in acute myocardial infarction on infarct size and left ventricular ejection fraction [ISRCTN56720616]

BACKGROUND: Favorable clinical outcomes have been observed with glucose-insulin-potassium infusion (GIK) in acute myocardial infarction (MI). The mechanisms of this beneficial effect have not been delineated clearly. GIK has metabolic, anti-inflammatory and profibrinolytic effects and it may preserve the ischemic myocardium. We sought to assess the effect of GIK infusion on infarct size and left ventricular function, as part of a randomized controlled trial. METHODS: Patients (n = 940) treated for acute MI by primary percutaneous coronary intervention (PCI) were randomized to GIK infusion or no infusion. Endpoints were the creatinine kinase MB-fraction (CK-MB) and left ventricular ejection fraction (LVEF). CK-MB levels were determined 0, 2, 4, 6, 24, 48, 72 and 96 hours after admission and the LVEF was measured before discharge. RESULTS: There were no differences between the two groups in the time course or magnitude of CK-MB release: the peak CK-MB level was 249 ± 228 U/L in the GIK group and 240 ± 200 U/L in the control group (NS). The mean LVEF was 43.7 ± 11.0 % in the GIK group and 42.4 ± 11.7% in the control group (P = 0.12). A LVEF ≤ 30% was observed in 18% in the controls and in 12% of the GIK group (P = 0.01). CONCLUSION: Treatment with GIK has no effect on myocardial function as determined by LVEF and by the pattern or magnitude of enzyme release. However, left ventricular function was preserved in GIK treated patients

Canagliflozin and Renal Outcomes in Type 2 Diabetes and Nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to 300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m 2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years