신장 아밀로이드증

Abstract

Amyloid is a fibrous quaternary structure formed by the assembly of protein or peptide monomers into intermolecularly hydrogen bonded β-sheet. Amyloid fibrils have a characteristic β-pleated sheet configuration that stain with the Congo red dye, producing a red shift in the light absorption of the dye and a characteristic apple-green birefringence under polarized light. Amyloidosis are characterized by the deposition of extracellular fibrils in various tissues. Amyloid deposits can be derived from at least 27 different types of precursor proteins and several variants. Classification of the amyloidosis is based upon the precursor protein that forms the amyloid fibrils, and the distribution of amyloid deposition. Systemic amyloidosis is a group of disorders that certainly leads to fatal multiorgan failure and relatively common cause of renal disease and proteinuria. Establishing the correct diagnosis is multidisciplinary and demands careful clinical evaluation with immunohistochemical studies. Ultimately the diagnosis of amyloidoisis is usually made by tissue biopsy of an affected organ. Immunohistochemistry is the standard technique used for typing of amyloid. Serum amyloid P component labeled with radioactive 123I has been used as a tracer to detect amyloid and to determine extend and distribution of amyloid deposits. The most common studied therapy interferes with production of precursor protein, with the goal of preventing further fibril formation. Another approach of amyloidosis therapy is to stabilize the native structure of the precursor protein and thus prevent its transition to a misfolded protein. Diflunisal-mediated kinetic stabilization of transthyretin (TTR) should ameliorate TTR amyloidoses, provided that nonsteroidal anti-inflammatory drug liabilities can be managed clinically. A third approach targets amyloid deposits directly, by destabilizing amyloid fibrils so that they can no longer maintain their β-pleated sheet configuration. Eprodisate is a new class of compounds designed to interfere with interactions between amyloidogenic proteins and glycosaminoglycans. Eprodisate binds to glycosaminoglycanbinding sites on the amyloid fibrils and thereby causing regression of amyloidosis. Targeting amyloid formation directly is a new direction that offers hope to patients with serious organ dysfunction. Although the management of amyloidosis has been frustrating, specific anti-amyloid drugs will become available in the near future.