Lipoprotein glomerulopathy: A new aspect of lipid induced glomerular injury

Abstract

Summary: Lipoprotein glomerulopathy is a new type of glomerular disease which is thought to be induced by an abnormality of lipoprotein metabolism. Until the end of 1994, 21 cases had been reported from Japan. However, this disease is not restricted to Japan because two cases with similar features have been described in France and the United States recently. Clinically, the presenting feature in all patients is proteinuria, resulting in a nephrotic syndrome in the majority. Renal biopsy specimens reveal that capillary lumina in the glomerulus are markedly dilated with pale‐stained and mesh‐like substances which are composed of fine granules. Under electron microscopy, it is observed that a combination of granules forms strata as fingerprints. Sudan or oil red‐O staining and immunofluorescence study on snap‐frozen sections show lipid droplets and apolipoproteins (apos) B and E in the capillary lumina, respectively. Accordingly, the intracapillary substances are thought to be lipoprotein thrombi. Lipid and lipoprotein profiles show type III hyperlipoproteinaemia and high level of apo E in plasma. However, the apo E phenotype is usually the heterozygous E2/3 or E2/4, different from the homozygous E2/2 in familial type III hyperlipoproteinaemia. Systemic manifestations characteristic of the previously‐reported lipidoses are not observed.Occurrence in several families and recurrence in two transplanted kidneys suggest that the disease may be induced by the hereditary abnormalities of lipoprotein metabolism. On the other hand, it is likely that in situ mechanisms may mediate development of the disease in the glomerulus.