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Objective: To analyse hepatitis C virus (HCV) transmission in a cohort of heterosexual couples who are discordant both for HIV and for HCV. Methods:We followed an open cohort of 171 people, 152 women and 19 men, who were not initially infected by either HIV or HCV, and whose steady heterosexual partner presented antibodies to both viruses (index case). Other risk exposures were excluded. Every 6 months clinical, epidemiological, and risk behaviour information was collected, and antibodies to both viruses were determined. Results: During 529 person years of follow up more than 40 000 vaginal or anal penetrations were recorded. 74 partners (43.3%) had vaginal and/or anal intercourse without condoms with the index case; another 15.8%, who always used condoms, declared breaking or slipping episodes during intercourse; and another 22.2% had unprotected orogenital exposures. During the follow up, over 5800 unprotected vaginal and anal contacts with the index case were estimated, as well as more than 25 000 unprotected orogenital contacts. 31 women became pregnant (two were index cases), and seroconversion to HIV occurred for one woman (1.7 per 10 000 unprotected contacts; 95% CI, 0 to 9.5), but there was no seroconversion to HCV (95% CI, 0-6.3 per 10 000 unprotected contacts). Conclusion: These results are consistent with a low or null transmissibility of HCV in heterosexual relations, even when the index case is HIV co-infected.

Inducible nitric oxide (NO) produced by macrophages is cytotoxic to invading organisms and has an important role in host defense. Recent studies have demonstrated inducible NO production within the heart, and that cytokine-induced NO mediates alterations in cardiac contractility, but the cytotoxic potential of nitric oxide with respect to the heart has not been defined. To evaluate the role of inducible nitric oxide synthase (iNOS) on cardiac myocyte cytotoxicity, we exposed adult rat cardiac myocytes to either cytokines alone or to activated J774 macrophages in coculture. Increased expression of both iNOS message and protein was seen in J774 macrophages treated with IFNy and LPS and cardiac myocytes treated with TNF-a, EL-1lf, and IFNy. Increased NO synthesis was confirmed in both the coculture and isolated myocyte preparations by increased nitrite production. Increased NO synthesis was associated with a parallel increase in myocyte death as measured by CPK release into the culture medium as well as by loss of membrane integrity, visualized by trypan blue staining. Addition of the competitive NO synthase inhibitor L-NMMA to the culture medium prevented both the increased nitrite production and the cytotoxicity observed after cytokine treatment in both the isolated myocyte and the coculture experiments. Because transforming growth-factor beta modulates iNOS expression in other cell types, we evaluated its effects on cardiac myocyte iNOS expression and NO-mediated myocyte cytotoxicity.TGF-fi reduced expression of cardiac myocyte iNOS message and protein, reduced nitrite production, and reduced NO-mediated cytotoxicity in parallel. Taken together, these experiments show the cytotoxic potential of endogenous NO production within the heart, and suggest a role for TGF-fi or NO synthase antagonists to mute these lethal effects.

In liver cirrhosis, abnormal liver architecture impairs efficient transduction of hepatocytes with large viral vectors such as adenoviruses. Here we evaluated the ability of adeno-associated virus (AAV) vectors, small viral vectors, to transduce normal and cirrhotic rat livers. Using AAV serotype-1 (AAV1) encoding luciferase (AAV1Luc) we analyzed luciferase expression with a CCD camera. AAV1Luc was injected through the hepatic artery (intra-arterial (IA)), the portal vein (intra-portal (IP)), directly into the liver (intra-hepatic (IH)) or infused into the biliary tree (intra-biliar). We found that AAV1Luc allows long-term and constant luciferase expression in rat livers. Interestingly, IP administration leads to higher expression levels in healthy than in cirrhotic livers, whereas the opposite occurs when using IA injection. IH administration leads to similar transgene expression in cirrhotic and healthy rats, whereas intra-biliar infusion is the least effective route. After 70% partial hepatectomy, luciferase expression decreased in the regenerating liver, suggesting lack of efficient integration of AAV1 DNA into the host genome. AAV1Luc transduced mainly the liver but also the testes and spleen. Within the liver, transgene expression was found mainly in hepatocytes. Using a liver-specific promoter, transgene expression was detected in hepatocytes but not in other organs. Our results indicate that AAVs are convenient vectors for the treatment of liver cirrhosis.