Lipid islands in human gastric mucosa: morphological and immunohistochemical findings

Lipid islands are a common finding in the gastric mucosa, but their pathogenesis has not yet been established. The aim of this study was to investigate the morphology and immunophenotype of the various cells in lipid islands and to consider the possible mechanisms involved in the pathogenesis of these lesions.

Morphological and immunohistochemical investigations using antibodies against macrophages, smooth muscle cells, and lymphocytes were performed. Unfixed tissue was available for immunostaining for low-density lipoprotein (LDL) and oxidized LDL in one case.

The lipid islands were composed of KP1-, KiM1p-, and cathepsin D-positive foam cells that were only weakly reactive for lysozyme. In cryostat sections, the foam cells were found to contain LDL and oxidized LDL. A few smooth muscle cells, plasma cells, lymphocytes, pericytes, fibroblasts, and Schwann cells that contained lipid droplets were also found.

In gastric lipid islands, the presence of oxidized LDL, which is taken up by macrophages and smooth muscle cells via scavenger receptors, suggests that oxidized LDL is of key significance in the development and persistence of these lesions. Because the metabolism of LDL to oxidized LDL may occur by various mechanisms, various different initial conditions, including gastritis, may precede the development of lipid islands. Thus, anti-inflammatory treatment may be appropriate.