Vitamin D deficiency contributes to the reduction and impaired function of naïve CD45RA⁺ regulatory T cell in chronic heart failure.

The effect of vitamin D pertinent to cardiovascular health on the heart itself is considered to shift toward an anti-inflammatory response in chronic heart failure (CHF); however, its underlying mechanism is not completely understood. In this study, we demonstrated that plasma 25(OH)D level, negatively associated with NT-ProBNP, correlated with the decreased Treg in CHF compared to the patients with other cardiovascular diseases and healthy and older donors. Naïve Treg cell (CD4(+)CD45RA(+)Foxp3(lo)T) subset, rather than whole Treg cells, contributes to the reduction of Treg in CHF. 1,25(OH)2D treatment maintained partial expression of CD45RA on CD4(+)T cell after αCD3/CD28 monoclonal antibodies activation and ameliorated the impaired CD4(+)CD45RA(+)T cell function from CHF patients through upregulating Foxp3 expression and IL-10 secretion in vitro. Low level of vitamin D receptor (VDR) was detected in CD4(+)CD45RA(+)T cell of CHF than control, while 1,25(OH)2D treatment increased the VDR expression to exert its immunosuppression on T cell. The results of this study might provide tangible evidence to our knowledge of the impact of vitamin D supplementation on naïve Tregs, which may offer new means of preventing and treating CHF.

Immunomodulatory effects of dietary supplementation with a milk-based wolfberry formulation in healthy elderly: a randomized, double-blind, placebo-controlled trial.

Wolfberry (fruit of Lycium barbarum) has been prized for many years in China for its immunomodulatory property and its high specific antioxidant content. However, clear clinical evidence demonstrating the effect of wolfberry dietary supplementation is still lacking. After our earlier report showing that a proprietary milk-based wolfberry formulation (Lacto-Wolfberry) enhances in vivo antigen-specific adaptive immune responses in aged mice, the present study aimed at demonstrating the effect of dietary Lacto-Wolfberry supplementation on immune functions in the elderly, especially vaccine response known to decline with aging. A 3-month randomized, double-blinded, placebo-controlled study was conducted on 150 healthy community-dwelling Chinese elderly (65-70 years old) supplemented with Lacto-Wolfberry or placebo (13.7 grams/day). Immune response to influenza vaccine was assessed in the study, along with inflammatory and physical status. No serious adverse reactions were reported during the trial, neither symptoms of influenza-like infection. No changes in body weight and blood pressure, blood chemistry or cells composition, as well as autoantibodies levels were observed. The subjects receiving Lacto-Wolfberry had significantly higher postvaccination serum influenza-specific immunoglobulin G levels and seroconversion rate, between days 30 and 90, compared with the placebo group. The postvaccination positive rate was greater in the Lacto-Wolfberry group compared to the placebo group, but did not reach statistical significance. Lacto-Wolfberry supplementation had no significant effect on delayed-type hypersensitivity response and inflammatory markers. In conclusion, long-term dietary supplementation with Lacto-Wolfberry in elderly subjects enhances their capacity to respond to antigenic challenge without overaffecting their immune system, supporting a contribution to reinforcing immune defense in this population.