Clinical benefits of a metabolic approach in the cardiac rehabilitation of patients with coronary artery disease

Facilitation of Insulin Effects by Ranolazine in Astrocytes in Primary Culture

Ranolazine (Rn) is a drug used to treat persistent chronic coronary ischemia. It has also been shown to have therapeutic benefits on the central nervous system and an anti-diabetic effect by lowering blood glucose levels; however, no effects of Rn on cellular sensitivity to insulin (Ins) have been demonstrated yet. The present study aimed to investigate the permissive effects of Rn on the actions of Ins in astrocytes in primary culture. Ins (10−8 M), Rn (10−6 M), and Ins + Rn (10−8 M and 10−6 M, respectively) were added to astrocytes for 24 h. In comparison to control cells, Rn and/or Ins caused modifications in cell viability and proliferation. Rn increased protein expression of Cu/Zn-SOD and the pro-inflammatory protein COX-2 was upregulated by Ins. On the contrary, no significant changes were found in the protein expression of NF-κB and IκB. The presence of Rn produced an increase in p-ERK protein and a significant decrease in COX-2 protein expression. Furthermore, Rn significantly increased the effects of Ins on the expression of p-AKT, p-eNOS, p-ERK, Mn-SOD, and PPAR-γ. In addition, Rn + Ins produced a significant decrease in COX-2 expression. In conclusion, Rn facilitated the effects of insulin on the p-AKT, p-eNOS, p-ERK, Mn-SOD, and PPAR-γ signaling pathways, as well as on the anti-inflammatory and antioxidant effects of the hormone.

The metabolic modulator trimetazidine triggers autophagy and counteracts stress-induced atrophy in skeletal muscle myotubes

It has recently been demonstrated that trimetazidine (TMZ), an anti-ischemic antianginal agent, is also able to improve exercise performance in patients with peripheral arterial disease. TMZ is a metabolic modulator, and the mechanisms underlying its cytoprotective anti-ischemic activity could be ascribed, at least in cardiomyocytes, to optimization of metabolism. However, regarding the cytoprotection exerted by TMZ on skeletal muscle and allowing the improvement of exercise performance, no information is yet available. In the present study, we investigated in detail the protective effects of this drug on in vitro skeletal muscle models of atrophy. Experiments carried out with murine C2C12 myotubes treated with TMZ revealed that this drug could efficiently counteract the cytopathic effects induced by the proinflammatory cytokine tumor necrosis factor-α and by the withdrawal of growth factors. Indeed, TMZ significantly counteracted the reduction in myotube size induced by these treatments. TMZ also increased myosin heavy chain expression and induced hypertrophy in C2C12 myotubes, both effects strongly suggesting a role of TMZ in counteracting atrophy in vitro. In particular, we found that TMZ was able to activate the phosphoinositide 3-kinase-Akt-mammalian target of rapamycin 2 pathway and to reduce the stress-induced transcriptional upregulation of atrogin-1, muscle ring finger protein 1, and myostatin, all of which are key molecules involved in muscle wasting. Moreover, this is the first demonstration that TMZ induces autophagy, a key mechanism involved in muscle mass regulation. On the basis of these results, it can be hypothesized that the improvement in exercise performance previously observed in patients could be ascribed to a cytoprotective mechanism exerted by TMZ on skeletal muscle integrity.

The effect of trimetazidine on cardiac function in diabetic patients with idiopathic dilated cardiomyopathy

AIMS

Trimetazidine is an anti-ischemic metabolic agent which improves myocardial glucose utilization. Whether it may improve cardiac function and physical tolerance in diabetic patients with idiopathic dilated cardiomyopathy is still not confirmed. In this study we have investigated the effectiveness of trimetazidine in these patients.

MAIN METHODS

Volunteers with diabetes and idiopathic dilated cardiomyopathy were recruited for participation in this study. Patients were randomized into two groups. One group received trimetazidine (20mg, t.i.d.) for 6 months (n=40), while another group received a placebo during the same period (n=40). All patients received an echocardiographic examination, 6-minute walk test and an inflammation biochemical analysis (C reactive protein) at baseline and after 6 months of treatment.

KEY FINDINGS

No significant adverse events or changes in clinical or biochemical parameters were detected through the study. After 6 months, TMZ-treated patients had a significant improvement in systolic function as compared with control patients associated with an increased ratio of E/A. C reactive protein concentrations remained stable throughout the study in trimetazidine group at baseline and at the 6 month on follow up. In comparison, it increased significantly in the control group at the 6-month follow up. The NT-pro BNP levels did not change in the control group, whereas they significantly decreased in the trimetazidine group. The physical activity tolerance level improved in the trimetazidine group compared to the control group.

SIGNIFICANCE

Trimetazidine treatment was associated with a significant improvement of cardiac function and physical tolerance. Results also suggested that the inflammatory response was decreased in trimetazidine group as compared with control patients.

Trimetazidine potentiates the effects of exercise training in patients with ischemic cardiomyopathy referred for cardiac rehabilitation

BACKGROUND

Patients referred for cardiac rehabilitation may take advantage from combining trimetazidine (TMZ) with exercise training (ET), as both treatments produce similar effects in the cardiovascular system. It is, however, unknown whether the combination of TMZ with ET may determine greater improvements in functional capacity and endothelial function than ET alone.

DESIGN

A randomized longitudinal controlled study.

METHODS

We studied 116 patients (97 men and 19 women, mean age 58+/-9 years) with ischemic heart disease and left ventricular dysfunction who were referred for cardiac rehabilitation. Coronary risk factors were present in 82 patients (diabetes in 28 patients). Patients were randomized into three matched groups. A group (TMZ+training, TT, n=30) received TMZ at doses of 20 mg three times daily orally for 8 weeks in addition to standard medications and underwent a supervised program of ET at 60% of oxygen uptake at peak, three times a week for 8 weeks. A group (exercise, E, n=30) completed the ET program without receiving TMZ. A control group (C, n=26) was neither exercised nor received TMZ. A fourth group (TMZ, n=30) receiving TMZ 20 mg three times daily for 8 weeks was also studied. On study entry and at 8 weeks all patients underwent echocardiography, cardiopulmonary exercise testing, and vasomotor reactivity of the brachial artery.

RESULTS

Oxygen uptake at peak was significantly increased in the TT (25%), TMZ (15.1%), and E group (15.3%) (P<0.001 TT vs. C; P<0.05 vs. TMZ and E). Left ventricular ejection fraction was also improved in TT (18.4%), TMZ (15.7%), and E (12.9%) (P<0.001 TT vs. C; P<0.05 vs. TMZ and E), as a result of reduction in end-systolic volume. The endothelium-dependent dilation was similarly improved (P<0.001 TMZ vs. C; P<0.05 vs. TMZ and E). The most significant improvements were observed in the subgroup TT with multiple risk factors.

CONCLUSION

The addition of TMZ to ET determined greater improvements in functional capacity, left ventricular ejection fraction, and endothelium-dependent dilation than TMZ or ET given alone. No differences between improvements after TMZ and E as compared with controls were observed.