The interaction of zinc and vitamin A in human schistosomiasis

Abstract

Levels of vitamin A and components of its transport protein complex, retinol binding protein and prealbumin, as well as Zn and its major binding proteins albumin and .alpha. 2-macrogloblin were measured in plasma of 91 male Egyptian patients with active schistosomal infection and 32 healthy adult males. Patients were divided into 4 groups: group I had active schistosomiasis without associated complications; group II had schistosomiasis complicated by colonic polyposis; group III had advanced schistosomiasis, hepatosplenomegaly and/or ascites; and group IV had chronic salmonella septicemia in addition to schistosomiasis. Results showed that all patient groups had subnormal levels of plasma vitamin A, retinol binding protein, prealbumin, Zn and albumin (P < 0.005 for all parameters) but elevated .alpha.2-macroglobulin (P < 0.001) when compared to the control group. Alterations in the vitamin A transport proteins increased with schistosomal complications and were closely correlated to changes in vitamin A (P < 0.005), but alterations of albumin and .alpha.2-macroglobulin were less consistent and did not correlate with changes in Zn levels. There was a highly significant correlation between plasma Zn concentrations and those of vitamin A, retinol binding protein and prealbumin (P < 0.001 for all correlations) in all groups of patients as well as the control group. Apparently, the binding and transport proteins of both Zn and vitamin A were adversely affected by schistosomiasis and its various complications. Deficiencies of both Zn and vitamin A seem to be interrelated in this disease and the vitamin A transport system may be largely dependent on Zn status.