Antimicrobial Effect of 1,25 Dihydroxy Vitamin D on Vibrio cholerae and its Association with Serum 25-Hydroxy Vitamin D Level in Rural Elderly Women: An Experimental Study

Introduction: Aging is associated with a variety of functional, demographic and immunologic changes, responsible for increasing the incidence and severity of infectious diseases in the elderly. Aim: To examine the association of serum 25-hydroxy vitamin D status with antimicrobial activity of cultured macrophages isolated within an exclusively elderly population cohort and also to examine the effect of in-vitro 1,25 hydroxy vitamin D supplementation in it. Materials and Methods: This experimental study was conducted among 113 elderly women aged between 60 to 70 years of age, during the period of April 2014 to August 2018, at Amdanga block, North 24th parganas, West Bengal, India. Their vitamin D status was assessed by the estimation of serum 25-hydroxy vitamin D and classified into three groups, sufficient group (60 subjects), insufficient group (27 subjects) and deficient group (26 subjects). Later their Peripheral Blood Mononuclear Cells (PBMC) were isolated and cultured from fresh blood of each and every study subject. Supplementation of 1,25 dihydroxy vitamin D {1,25(OH)(2)D} was given selectively at a dose of 10 x 10(-8) M for 72 hours in the culture media and were exposed to Vibrio cholerae and inducible nitric oxide synthase (iNOS), Superoxide Dismutase (SOD) activity and Bactericidal activity were screened. Statistical Package for the Social Sciences (SPSS) software, version 20.0 was used to perform statistical analysis. Results: The sufficient group iNOS activity had significantly higher than the other two groups. Whereas in-vitro 1,25(OH)(2)D supplementation increases iNOS activity significantly among all three groups. As per the Colony Forming Unit (CFU) reduction rate against Vibrio cholerae infection the sufficient serum 25(OH)D consisting group had significantly (p-value=0.03) high CFU reduction rate than the other two groups. Although in-vitro 1,25(OH)(2)D supplementation had no significant impact on CFU reduction rate among all three groups. Conclusion: Bacteria killing capacity of macrophages varies significantly with serum 25-hydroxy vitamin D level of the target population. Sufficient group macrophages always had better profile than other two groups. In-vitro 1,25(OH)(2)D supplementation increases iNOS and SOD activity significantly.