Vascular anomalies in lipoid proteinosis (hyalinosis cutis et mucosae): basement membrane components and ultrastructure.

Background: In lipoid proteinosis (LP) vascular anomalies represent severe functional defects caused by excessive deposition of basement membrane (BM)-like matrix, particularly around small subepithelial blood vessels.

Objective: Correlation of microvascular anomalies in morphology and ultrastructure with extracellular matrix composition and cell interactions for elucidating vascular involvement in LP-pathophysiology.

Methods: Biopsies from non-related LP-patients were analyzed by indirect immunofluorescence (IIF), electron microscopy (EM), and immune-EM (ImEM).

Inhibition of basement membrane formation by a nidogen-binding laminin gamma1-chain fragment in human skin-organotypic cocultures.

Basement membranes generally determine different tissue compartments in complex organs, such as skin, playing not only an important structural but also a regulatory role. We have previously demonstrated the formation of a regular basement membrane in organotypic three-dimensional (3D)-cocultures of human skin keratinocytes and fibroblasts by indirect immunofluorescence and transmission electron microscopy. In this assembly process, cross-linking of type IV collagen and the laminin gamma1 chain by nidogen is considered a crucial step.