Microcirculatory Regulation and Dysfunction

Abstract

Since reticuloendothelial (RE) cells are constituents of the vascular system, they can be affected, primarily, by two agencies—microcirculatory vasomotor behavior and/or vasoactive substances in the blood or lymph. Uptake of particulate matter, microorganisms, and foreign proteins by the phagocytic elements of the RES (see Table 1) is dependent on blood flow (see Altura, 1980a, 1983, 1984b; Altura and Saba, 1981; Benacerraf et al, 1957; Normann, 1972, 1973; Saba, 1970; Stuart, 1970). The data shown in Fig. 1, obtained on an isolated perfused rat liver preparation, resulted from one of the first experiments (performed by E. Dobson) to clearly demonstrate an inverse correlation between the velocity of flow past the Kupffer cell phagocytes and the efficiency of these phagocytes in removing chromic phosphate from the passing blood. In other terms, these relatively early experiments show a relation between extraction efficiency and a blood perfusion factor. Such data thus point to velocity of flow and tissue perfusion as important factors influencing RES phagocytic efficiency. Thus, both alterations in microcirculatory hemodynamics and release (or synthesis and release) of vasoactive agents could be expected to exert pronounced effects on RES phagocytic function. One might, especially in circulatory shock and trauma syndromes, therefore expect both of the latter to strongly influence RE cell phagocytic extraction efficiency.