title: Role of complement and complement regulatory proteins in the complications of diabetes.
abstract: It is well established that the organ damage that complicates human diabetes is caused by prolonged hyperglycemia, but the cellular and molecular mechanisms by which high levels of glucose cause tissue damage in humans are still not fully understood. The prevalent hypothesis explaining the mechanisms that may underlie the pathogenesis of diabetes complications includes overproduction of reactive oxygen species, increased flux through the polyol pathway, overactivity of the hexosamine pathway causing intracellular formation of advanced glycation end products, and activation of protein kinase C isoforms. In addition, experimental and clinical evidence reported in past decades supports a strong link between the complement system, complement regulatory proteins, and the pathogenesis of diabetes complications. In this article, we summarize the body of evidence that supports a role for the complement system and complement regulatory proteins in the pathogenesis of diabetic vascular complications, with specific emphasis on the role of the membrane attack complex (MAC) and of CD59, an extracellular cell membrane-anchored inhibitor of MAC formation that is inactivated by nonenzymatic glycation. We discuss a pathogenic model of human diabetic complications in which a combination of CD59 inactivation by glycation and hyperglycemia-induced complement activation increases MAC deposition, activates pathways of intracellular signaling, and induces the release of proinflammatory, prothrombotic cytokines and growth factors. Combined, complement-dependent and complement-independent mechanisms induced by high glucose promote inflammation, proliferation, and thrombosis as characteristically seen in the target organs of diabetes complications.
authors: Division of Hematology, Department of Medicine (P.G., R.S., M.C., J.A.H.), and Division of Endocrinology, Diabetes, and Hypertension (A.V.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors: Pamela
authors: P
authors: Ghosh
authors: Division of Hematology, Department of Medicine (P.G., R.S., M.C., J.A.H.), and Division of Endocrinology, Diabetes, and Hypertension (A.V.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors: Rupam
authors: R
authors: Sahoo
authors: Division of Hematology, Department of Medicine (P.G., R.S., M.C., J.A.H.), and Division of Endocrinology, Diabetes, and Hypertension (A.V.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors: Anand
authors: A
authors: Vaidya
authors: Division of Hematology, Department of Medicine (P.G., R.S., M.C., J.A.H.), and Division of Endocrinology, Diabetes, and Hypertension (A.V.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors: Michael
authors: M
authors: Chorev
authors: Division of Hematology, Department of Medicine (P.G., R.S., M.C., J.A.H.), and Division of Endocrinology, Diabetes, and Hypertension (A.V.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors: Jose A
authors: JA
authors: Halperin
mesh_terms: D000818:Animals; D018957:CD59 Antigens / Q000378:metabolism*; D015938:Complement Membrane Attack Complex / Q000378:metabolism*; D003165:Complement System Proteins / Q000378:metabolism*; D003925:Diabetic Angiopathies / Q000276:immunology / Q000378:metabolism*; D006801:Humans
chemical_list: D018957:CD59 Antigens; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins