Effects of pomegranate peel extract and vitamin E on the inflammatory status and endothelial function in hemodialysis patients: a randomized controlled clinical trial
Tina Jafari, Aziz A. Fallah, Ali Reyhanian, Elham Sarmast
Abstract
Inflammation and endothelial dysfunction are major problems in hemodialysis (HD) patients. This study assessed the effects of an 8 week administration of pomegranate peel extract (PPE) and vitamin E (Vit E) alone or in combination on the biomarkers of inflammation, including C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), and the biomarkers of endothelial function, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and P-selectin, in HD patients. In a randomized, double-blind, parallel, placebo-controlled trial, 100 HD patients were randomly divided into 4 equal groups: (a) PPE + Vit E, received 2 pomegranate tablets (each tablet contained 225 mg PPE, equal to 90 mg ellagic acid) + 1 Vit E soft gel (400 IU) daily, (b) PPE, received 2 pomegranate tablets + 1 Vit E placebo soft gel daily, (c) Vit E, received 1 Vit E soft gel + 2 pomegranate placebo tablets daily, and (d) placebo, received 2 pomegranate placebo tablets + 1 Vit E placebo soft gel daily. For group allocation, a stratified block randomization procedure based on sex, age, and HD duration was used. Each intervention product and its placebo had identical shape, color, size, and packaging. Consumption of PPE + Vit E significantly reduced the serum CRP level (mean change: -7.12 ± 4.59 mg l-1, P < 0.001) compared to other groups, while reduced levels of IL-6 (mean change: -2.19 ± 2.33 pg ml-1, P < 0.001), TNF-α (mean change: -2.41 ± 3.21 pg ml-1, P = 0.008), ICAM-1 (mean change: -64.2 ± 111.0 ng ml-1, P = 0.017), and VCAM-1 (mean change: -117.7 ± 177.1 ng ml-1, P = 0.002) were observed compared to the control. There was no significant difference in the P-selectin level among the groups. Consumption of PPE or Vit E alone significantly reduced the CRP level (mean change for PPE: -3.58 ± 5.41 mg l-1, P < 0.001; mean change for Vit E: -3.25 ± 8.29 mg l-1, P = 0.002) compared to the control. As a result, consumption of PPE in combination with Vit E enhanced the inflammatory status and endothelial function in HD patients.