Poorly controlled type 2 diabetes is accompanied by significant morphological and ultrastructural changes in both erythrocytes and in thrombin-generated fibrin: implications for diagnostics

We have noted in previous work, in a variety of inflammatory diseases, where iron dysregulation occurs, a strong tendency for erythrocytes to lose their normal discoid shape and to adopt a skewed morphology (as judged by their axial ratios in the light microscope and by their ultrastructure in the SEM). Similarly, the polymerization of fibrinogen, as induced in vitro by added thrombin, leads not to the common ‘spaghetti-like’ structures but to dense matted deposits. Type 2 diabetes is a known inflammatory disease. In the present work, we found that the axial ratio of the erythrocytes of poorly controlled (as suggested by increased HbA1c levels) type 2 diabetics was significantly increased, and that their fibrin morphologies were again highly aberrant. As judged by scanning electron microscopy and in the atomic force microscope, these could be reversed, to some degree, by the addition of the iron chelators deferoxamine (DFO) or deferasirox (DFX). As well as their demonstrated diagnostic significance, these morphological indicators may have prognostic value.Biotechnology and Biological Sciences Research Council (grant BB/L025752/1) as well as the National Research Foundation (NRF) of South Africa.http://www.cardiab.com/hb201

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Microangiopathy in Patients on Cyclosporine Prophylaxis Who Developed Acute Graft-Versus- Host Disease After HLA-Identical Bone Marrow Transplantation.

Severe microangiopathy has been reported as a rare complication of cyclosporine A (CsA) prophylaxis in allogeneic bone marrow transplantation (BMT). We found morphological and biochemical changes indicative of generalized endothelial damage in 49 of 66 allogeneic marrow graft recipients receiving cyclosporine, but none in 11 patients treated with methotrexate for prophylaxis of graft-v-host disease (GVHD). Changes occurred after engraftment of bone marrow and consisted of intravascular hemolysis with red cell fragmentation and de novo thrombocytopenia. They were preceded by a decrease in activated partial thromboplastin time and fibrinogen indicating activation of coagulation. Endothelial damage as the central lesion of microangiopathy was confirmed by a simultaneous increase of factor VIII related antigen. Severe microangiopathy was observed in ten patients and was fatal in seven. Risk factor analysis revealed a highly significant association of microangiopathy with severity of acute GVHD (aGVHD) (P less than .001) and use of CsA prophylaxis (P less than .001). Our data suggest endothelial damage as a result of cellular activation and subsequent release of cytokines in the course of a aGVHD, which is not inhibited by CsA prophylaxis