Prune Consumption Attenuates Proinflammatory Cytokine Secretion and Alters Monocyte Activation in Postmenopausal Women: Secondary Outcome Analysis of a 12-Mo Randomized Controlled Trial: The Prune Study

• Published in: The Journal of nutrition 2024-05, Vol.154 (5), p.1699-1710
• Main Authors: Damani, Janhavi J, Oh, Ester S, De Souza, Mary Jane, Strock, Nicole Ca, Williams, Nancy I, Nakatsu, Cindy H, Lee, Hang, Weaver, Connie, Rogers, Connie J
• Format: Article
• Language: English
• Subjects: Aged; Antioxidants - administration & dosage; Antioxidants - metabolism; Antioxidants - pharmacology; Biomarkers - blood; Blood; Bone loss; Bone mineral density; C-reactive protein; C-Reactive Protein - metabolism; Cell activation; Cell culture; Circulation; Clinical trials; Cytokines; Cytokines - blood; Cytokines - metabolism; Dietary Supplements; Dinoprost - analogs & derivatives; Dinoprost - blood; Dinoprost - metabolism; Female; Humans; IL-1β; Inflammation; Interleukin 6; Interleukin 8; Leukocytes (mononuclear); Lipopolysaccharides; Menopause; Middle Aged; Monocyte chemoattractant protein; Monocyte chemoattractant protein 1; Monocytes; Monocytes - drug effects; Monocytes - metabolism; Nutritional Immunology; Oxidative stress; Oxidative Stress - drug effects; Peripheral blood mononuclear cells; Post-menopause; Postmenopause; Proteins; Secondary analysis; Tumor necrosis factor-TNF; Tumor necrosis factor-α
• ISSN: 0022-3166; 1541-6100; 1541-6100
• DOI: 10.1016/j.tjnut.2023.11.014

Proinflammatory cytokines are implicated in the pathophysiology of postmenopausal bone loss. Clinical studies demonstrate that prunes prevent bone mineral density loss; however, the mechanism underlying this effect is unknown. We investigated the effect of prune supplementation on immune, inflammatory, and oxidative stress markers. A secondary analysis was conducted in the Prune Study, a single-center, parallel-arm, 12-mo randomized controlled trial of postmenopausal women (55-75 y old; n = 235 recruited; n = 183 completed) who were assigned to 1 of 3 groups: "no-prune" control, 50 g prune/d and 100 g prune/d groups. At baseline and after 12 mo of intervention, blood samples were collected to measure serum high-sensitivity C-reactive protein (hs-CRP), serum total antioxidant capacity (TAC), plasma 8-isoprostane, proinflammatory cytokines [interleukin (IL)-1β, IL-6, IL-8, monocyte chemoattractant protein-1, and tumor necrosis factor (TNF)-α] concentrations in plasma and lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs) culture supernatants, and the percentage and activation of circulating monocytes, as secondary outcomes. Prune supplementation did not alter hs-CRP, TAC, 8-isoprostane, and plasma cytokine concentrations. However, percent change from baseline in circulating activated monocytes was lower in the 100 g prune/d group compared with the control group (mean ± SD, -1.8% ± 4.0% in 100 g prune/d compared with 0.1% ± 2.9% in control; P < 0.01). Furthermore, in LPS-stimulated PBMC supernatants, the percent change from baseline in TNF-α secretion was lower in the 50 g prune/d group compared with the control group (-4.4% ± 43.0% in 50 g prune/d compared with 24.3% ± 70.7% in control; P < 0.01), and the percent change from baseline in IL-1β, IL-6, and IL-8 secretion was lower in the 100 g prune/d group compared with the control group (-8.9% ± 61.6%, -4.3% ± 75.3%, -14.3% ± 60.8% in 100 g prune/d compared with 46.9% ± 107.4%, 16.9% ± 70.6%, 39.8% ± 90.8% in control for IL-1β, IL-6, and IL-8, respectively; all P < 0.05). Dietary supplementation with 50-100 g prunes for 12 mo reduced proinflammatory cytokine secretion from PBMCs and suppressed the circulating levels of activated monocytes in postmenopausal women. This trial was registered at clinicaltrials.gov as NCT02822378.