Latent herpesvirus infection augments experimental pulmonary fibrosis.
ABSTRACT No effective treatment exists for idiopathic pulmonary fibrosis, and its pathogenesis remains unclear. Accumulating evidence implicates herpesviruses as cofactors (either initiating or exacerbating agents) of fibrotic lung disease, but a role for latent herpesvirus infection has not been studied.
To develop a murine model to determine whether latent herpesvirus infection can augment fibrotic responses and to gain insight into potential mechanisms of enhanced fibrogenesis.
Mice were infected with murine gammaherpesvirus 14 to 70 days before a fibrotic challenge with fluorescein isothiocyanate or bleomycin so that the virus was latent at the time of fibrotic challenge. Measurements were made after viral infection alone or after the establishment of fibrosis.
gammaHerpesvirus is latent by 14 days post infection, and infection 14 to 70 days before fibrotic challenge augmented fibrosis. Fibrotic augmentation was not dependent on reactivation of the latent virus to a lytic state. Total cell numbers and fibrocyte numbers were increased in the lungs of latently infected mice administered fibrotic challenge compared with mock-infected mice that received fibrotic challenge. Latent infection up-regulates expression of proinflammatory chemokines, transforming growth factor-beta1, and cysteinyl leukotrienes in alveolar epithelial cells.
Latent gammaherpesvirus infection augments subsequent fibrotic responses in mice. Enhanced fibrosis is associated with the induction of profibrotic factors and the recruitment of fibrocytes. Our data complement existing human and animal data supporting the hypothesis that gammaherpesviruses can serve as initiating cofactors in the pathogenesis of pulmonary fibrosis.
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ABSTRACT: Hypothesis. Repeated epithelial cell injury secondary to viruses such as Epstein Barr and subsequent dysfunctional repair may be central to the pathogenesis of IPF. In this observational study, we evaluated whether a combination of standard and anti-viral therapy might have an impact on disease progression. Methods. Advanced IPF patients who failed standard therapy and had serological evidence of previous EBV, received ganciclovir (iv) at 5 mg/kg twice daily. Forced vital capacity (FVC), shuttle walk test, DTPA scan and prednisolone dose were measured before and 8 weeks post-treatment. Results. Fourteen patients were included. After ganciclovir, eight patients showed improvement in FVC and six deteriorated. The median reduction of prednisolone dose was 7.5 mg (44%). Nine patients were classified “responders” of whom four showed an improvement in all four criteria, while three of the five “non-responders” showed no response in any of the criteria. Responders showed reduction in prednisolone dosage (P = .02) and improved DTPA clearance (P = .001). Conclusion. This audit outcome suggests that 2-week course of ganciclovir (iv) may attenuate disease progression in a subgroup of advanced IPF patients. These observations do not suggest that anti-viral treatment is a substitute for the standard care, however, suggests the need to explore the efficacy of ganciclovir as adjunctive therapy in IPF.04/2011; 2011(2090-1836):240805. DOI:10.1155/2011/240805
Article: The oxygen cycle.Scientific American 10/1970; 223(3):111-23. DOI:10.1016/S0065-2881(05)48006-2 · 1.33 Impact Factor
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ABSTRACT: Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disorder of unknown etiology. Several studies have demonstrated an association between pulmonary infection with a herpesvirus and IPF. Based on those observations, we have developed a mouse model in which interferon (IFN)gammaR(-/-) mice infected intranasally with murine gammaherpesvirus 68 (MHV68) develop lung fibrosis. We hypothesize that viral load was a critical factor for the development of fibrosis. Because nuclear factor (NF)-kappaB signaling is required to efficiently establish gammaherpesvirus, latency we infected IFNgammaR(-/-) mice with a MHV68 virus that expresses a mutant dominant inhibitor of the NF-kappaB signaling pathway, called IkappaBalphaM. Striking differences were observed at the onset of the chronic infection, which correlated with a decreased virus load in mice infected with MHV68-IkappaBalphaM compared with mice infected with control MHV68 (MHV68-MR). IFNgammaR(-/-) mice infected with MHV68-IkappaBalphaM lacked vasculitis and fibrosis 15 to 120 days post infection. Inhibition of NF-kappaB in MHV68-infected cells of the lungs diminished the expression of the fibrocyte recruiting chemokines monocyte chemoattractant protein 1 (MCP-1) and CXCL12, ameliorated macrophage expression of markers of alternative activation, and failed to increase expression of the integrin alphavbeta6, which is implicated in the activation of the profibrotic factor TGF-beta. Thus, the inhibition of NF-kappaB signaling in the infected lung cells of IFNgammaR(-/-) mice reduces virus persistence and ameliorates profibrotic events. Host determinants of latency might therefore represent new therapeutic targets for gammaherpesvirus-associated pulmonary fibrosis.American Journal Of Pathology 08/2010; 177(2):608-21. DOI:10.2353/ajpath.2010.091122 · 4.60 Impact Factor