Abstract 5060: The Effect of Aggressive Dietary Intervention on Endothelial Progenitor Cell Function in High Risk Cardiovascular Patients
Secondary prevention strategies aimed at the reduction of modifiable risk factors can improve outcomes and improve prognosis in high risk cardiovascular patients. Reduced endothelial progenitor cell (EPC) number and functionality, as observed in type II diabetes, reflects increased cardiac risk but nutritional modulation may positively influence endothelial function. Therefore, we hypothesize that an aggressive dietary intervention, the modified Portfolio Diet, would increase the number and/or functionality of EPCs in diabetic patients post-CABG.
Methods: 22 patients with type II diabetes, 6 weeks post bypass surgery received detailed individualized dietary counseling on the modified Portfolio Diet: a low cholesterol, low saturated fat diet that includes viscous fibres (8g/1000 kcal as psyllium and β-glucan), soy protein (17g/1000kcal) and almonds (22g/1000kcal). EPCs were isolated by Ficol gradient prior to study entry and at study completion (week 0 vs. week 4) and cultured on fibronectin coated culture slides. EPC number (CD34/CD133) was assayed by FACS analysis, EPC differentiation (UEA-1/VEGFR-2) was assayed by immunohistochemistry and apoptosis (Tunnel assay) was measured after 7 days of differential culture. EPC function was assayed in a modified Boyden chamber with SDF-1/VEGF as chemoattractants.
Results: After 4 weeks of dietary intervention, EPC number (% of circulating mononuclear cells which are CD34 (+) was significantly increased over pre-dietary levels (0.27 ± 0.14% v. 0.17 ± 0.08%, p < 0.01). EPC differentiation (% of cells staining for mature endothelial markers, VEGFR-2 and endothelial specific lectin UEA-1) was also significantly increased over pre-dietary levels (78.6 ± 7.9% v. 54.0 ± 14.6%, p < 0.01), while EPC apoptosis rate was unchanged. The migratory capacity of EPCs was significantly greater after 4-weeks on the portfolio diet, as shown by the number of cells migrating across the Boyden chamber (0.03 ± 0.02% v. 0.016 ± 0.014%, p <0.05).
Conclusions: Our results demonstrate that diabetic EPC number and function is improved by 4-weeks of an aggressive dietary intervention in high-risk cardiovascular patients, with significant improvements in circulating EPC numbers, EPC differentiation and function.