Human Immunodeficiency Virus-1 Transgene Expression Increases Pulmonary Vascular Resistance and Exacerbates Hypoxia-Induced Pulmonary Hypertension Development

Abstract

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by increased pulmonary arterial resistance and vessel remodeling. Patients living with human immunodeficiency virus-1 (HIV-1) have an increased susceptibility to develop severe pulmonary hypertension (PH) irrespective of their CD4+ lymphocyte counts. While the underlying cause of HIV-PAH remains unknown, the interaction of HIV-1 proteins with the vascular endothelium may play a critical role in HIV-PAH development. Hypoxia promotes PH in experimental models and in humans, but the impact of HIV-1 proteins on hypoxia-induced pulmonary vascular dysfunction and PAH has not been examined. Therefore, we hypothesize that the presence of HIV-1 proteins and hypoxia synergistically augment the development of pulmonary vascular dysfunction and PH. We examined the effect of HIV-1 proteins on pulmonary vascular resistance by measuring pressure-volume relationships in isolated lungs from wild-type (WT) and HIV-1 Transgenic (Tg) rats. WT and HIV-1 Tg rats were exposed to 10% O2 for four weeks to induce experimental pulmonary hypertension to assess whether HIV-1 protein expression would impact the development of hypoxia-induced PH. Our results demonstrate that HIV-1 protein expression significantly increased pulmonary vascular resistance (PVR). HIV-1 Tg mice demonstrated exaggerated pulmonary vascular responses to hypoxia as evidenced by greater increases in right ventricular systolic pressures, right ventricular hypertrophy and vessel muscularization when compared to wild-type controls. This enhanced PH was associated with enhanced expression of HIF-1α and PCNA. In addition, in vitro studies reveal that medium from HIV-infected monocyte derived macrophages (MDM) potentiates hypoxia-induced pulmonary artery endothelial proliferation. These results indicate that the presence of HIV-1 proteins likely impact pulmonary vascular resistance and exacerbate hypoxia-induced PH.

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Topics

Endothelin and Endothelium & Epithelium and Epithelial Transport
Hypoxia/ Intermittent Hypoxia/ Hypoxia-Ischemia and Ischemia-Reperfusion Injury
Pulmonary Vascular Remodeling

Authors

Kristi M. Porter, Erik R. Walp, Shawn C. Elms, Robert Raynor, Patrick O. Mitchell, David M. Guidot, Roy L. Sutliff

Published in:

Pulmonary Circulation Vol 3: No 1 cover image

March 2013

Pulmonary Circulation Vol 3: No 1

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