Distribution of integrin-like immunoreactivity on primate brain microvasculature

The objective of this immunohistochemical study was to detail the distribution patterns of alpha and beta integrin subunit expression in non-ischemic non-human primate brain in comparison to that reported for rodents and humans. For this purpose cerebral specimens were obtained from 3 adolescent male baboons by direct perfusion and immediate processing. Well-characterized monoclonal and polyclonal antibodies against human alpha and beta integrin subunit antigens were used to define their location and distribution relative to the markers for vascular basal lamina, laminin (LM). and astrocytic fibers or glial fibrillic acid protein (GFAP). Quantitation of microvascular epitopes required computerized videoimaging microscopy and laser confocal microscopy (LCM). Each subunit was categorized into one of four microvascular patterns relative to LM antigen: (a) all microvascular diameter categories-alpha(1), alpha(nu), and beta(1); (b) antigen-sparing capillaries alpha(2), alpha(1), alpha(5), alpha(v) and beta(3); (c) a subset of all microvascular diameter classes-alpha(3) beta(4), and beta(5); and (d) no antigen apparent, beta(2). Subunit antigens alpha(1), alpha(2), beta(1), and beta(5) were detected on perivascular astrocytes. Subunits alpha(1), and beta(1), and GFAP colocalized (LCM). This quantitative survey detailed specific microvascular and astrocyte associations of certain alpha and beta integrin subunits in non-human primate brain. Specific reproducible and consistent distributions of alpha and beta subunits form the basis for further investigation of their responses to focal ischemia in a human relevant system.