Background-Oxidative stress has been implicated in the pathogenesis of heart failure. However, direct evidence of oxidative stress generation in the human failing myocardium has not been obtained. Furthermore, the effect of carvedilol, a vasodilating ␤-blocker with antioxidant activity, on oxidative stress in human failing hearts has not been assessed. This study was therefore designed to determine whether levels of lipid peroxides are elevated in myocardia of patients with dilated cardiomyopathy (DCM) and whether carvedilol reduces the lipid peroxidation level. Methods and Results-Endomyocardial biopsy samples obtained from 23 patients with DCM and 13 control subjects with normal cardiac function were studied immunohistochemically for the expression of 4-hydroxy-2-nonenal (HNE)-modified protein, which is a major lipid peroxidation product. Expression of HNE-modified protein was found in all myocardial biopsy samples from patients with DCM. Expression was distinct in the cytosol of cardiac myocytes. Myocardial HNE-modified protein levels in patients with DCM were significantly increased compared with the levels in control subjects (PϽ0.0001). Endomyocardial biopsy samples from 11 patients with DCM were examined before and after treatment (mean, 9Ϯ4 months) with carvedilol (5 to 30 mg/d; mean dosage, 22Ϯ8 mg/d). After treatment with carvedilol, myocardial HNE-modified protein levels decreased by 40% (PϽ0.005) along with amelioration of heart failure. Conclusions-Oxidative stress is elevated in myocardia of patients with heart failure. Administration of carvedilol resulted in a decrease in the oxidative stress level together with amelioration of cardiac function.

IntroductionRecent studies have shown that histones, the chief protein component of chromatin, are released into the extracellular space during sepsis, trauma, and ischemia-reperfusion injury, and act as major mediators of the death of an organism. This study was designed to elucidate the cellular and molecular basis of histone-induced lethality and to assess the protective effects of recombinant thrombomodulin (rTM). rTM has been approved for the treatment of disseminated intravascular coagulation (DIC) in Japan, and is currently undergoing a phase III clinical trial in the United States.MethodsHistone H3 levels in plasma of healthy volunteers and patients with sepsis and DIC were measured using enzyme-linked immunosorbent assay. Male C57BL/6 mice were injected intravenously with purified histones, and pathological examinations were performed. The protective effects of rTM against histone toxicity were analyzed both in vitro and in mice.ResultsHistone H3 was not detectable in plasma of healthy volunteers, but significant levels were observed in patients with sepsis and DIC. These levels were higher in non-survivors than in survivors. Extracellular histones triggered platelet aggregation, leading to thrombotic occlusion of pulmonary capillaries and subsequent right-sided heart failure in mice. These mice displayed symptoms of DIC, including thrombocytopenia, prolonged prothrombin time, decreased fibrinogen, fibrin deposition in capillaries, and bleeding. Platelet depletion protected mice from histone-induced death in the first 30 minutes, suggesting that vessel occlusion by platelet-rich thrombi might be responsible for death during the early phase. Furthermore, rTM bound to extracellular histones, suppressed histone-induced platelet aggregation, thrombotic occlusion of pulmonary capillaries, and dilatation of the right ventricle, and rescued mice from lethal thromboembolism.ConclusionsExtracellular histones cause massive thromboembolism associated with consumptive coagulopathy, which is diagnostically indistinguishable from DIC. rTM binds to histones and neutralizes the prothrombotic action of histones. This may contribute to the effectiveness of rTM against DIC.

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Nucleoside 3'-O-bicylic oxazaphospholidine derivatives were designed as monomer units for a solid-phase synthesis of stereoregular oligodeoxyribonucleoside phosphorothioates (PS-ODNs). The trans-isomers of appropriately designed nucleoside 3'-O-bicyclic oxazaphospholidine derivatives were generated exclusively by the reaction between the 3'-OH of the corresponding protected nucleosides and 2-chloro-1,3,2-oxazaphospholidine derivatives. The resultant trans-oxazaphospholidine isomers were configurationally stable, and their diastereopurity was not impaired by epimerization in the presence of an acidic activator during the condensation on a solid support. As a result, the formation of both (Rp)- and (Sp)-phosphorothioate internucleotide linkages by using the oxazaphospholidine monomers and the acidic activator proceeded without any loss of diastereopurity (diastereoselectivity > or = 99:1). In addition, ab initio molecular orbital calculations showed that the epimerization of oxazaphospholidine derivatives was most likely to proceed via an edge inversion process that was accelerated by N-protonation. The calculations rationalized not only the relations between the ring structure and the configurational stability of the oxazaphospholidines observed in this study but also the observations reported in the literature that the inversion of tricoordinated organophosphorus compounds were accelerated by acids or nucleophiles.