Effects of pomegranate peel extract and vitamin E on inflammatory status and endothelial function of hemodialysis patients: A randomized controlled clinical trial
Inflammation and endothelial dysfunction are major problems in hemodialysis (HD) patients. This study assessed the effects of 8-week administration of pomegranate peel extract (PPE) and vitamin E (Vit E) alone or in combination on biomarkers of inflammation, including C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), and 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 to 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, 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 serum CRP level (mean change: -7.12 ± 4.59 mg/l, P < 0.001) compared to other groups, while reduced levels of IL-6 (mean change: -2.19 ± 2.33 pg/ml, P < 0.001), TNF-α (mean change: -2.41 ± 3.21 pg/ml, P = 0.008), ICAM-1 (mean change: -64.2 ± 111.0 ng/ml, P = 0.017), and VCAM-1 (mean change: -117.7 ± 177.1 ng/ml, P = 0.002) compared to control. There was no significant difference in P-selectin level among the groups. Consumption of PPE or Vit E alone significantly reduced CRP level (mean change for PPE: -3.58 ± 5.41 mg/l, P < 0.001; mean change for Vit E: -3.25 ± 8.29 mg/l, P = 0.002) compared to control. As a result, consumption of PPE in combination with Vit E enhanced inflammatory status and endothelial function in HD patients.