Involvement of specific laminins and nidogens in the active remodeling of the basal lamina of labial salivary glands from patients with Sögren's syndrome

Abstract

Objective. To investigate remodeling of the basal lamina of labial salivary glands (LSGs) from patients with Sjögren's syndrome (SS) by analyzing the expression of specific components that participate in its assembly and attachment to acinar and ductal cells. Methods. Two groups of SS patients with similar levels of remnant glandular tissue but with low and high levels of interacinar fibrosis, respectively, were studied. The expression of laminin α1, α4, and γ2 chains and nidogens was examined at the messenger RNA (mRNA) and protein levels. Nidogens 1 and 2 were also studied in situ by immunohistochemistry. Results. Increases in the amount of mRNA and protein for both the processed and unprocessed laminin γ2-chain were more pronounced in patients with low interacinar fibrosis. Increases in the protein levels of laminin α1 and α4 chains were observed in patients with low interacinar fibrosis, but not in those with high interacinar fibrosis. Nidogen mRNA and protein levels were similar i