HIV+ Alveolar Macrophage Oxidant-mediated Apoptosis of Pulmonary Endothelium

The purpose of this study is to analyze biologic samples from the blood, airways and/or urine of HIV- and HIV+ smokers and non-smokers to better understand the etiology and pathogenesis of emphysema in association with HIV infection. The underlying hypothesis is that the combination of HIV infection and smoking creates chronic oxidant stress in the lower respiratory tract that promotes cellular loss and contributes to the progressive development of emphysema. Preliminary data strongly supports our hypothesis that the accelerated development of emphysema among HIV+ smokers is due in part to the interaction of HIV directly on the macrophage found in the pulmonary alveolus. The interaction causes a release of exaggerated amounts of oxidants in the lower respiratory tract and leads to increased levels of oxidized metabolites. HIV+ individuals with emphysema have high plasma levels of apoptotic pulmonary capillary-derived micro particles that contain oxidized metabolites. The increased release of micro particles is characteristic of an apoptotic process.

We will study this hypothesis by sampling HIV+ and HIV- subjects alveolar macrophages (AM), which are found on the epithelial surface of the lung, and epithelial lining fluid (ELF) found in the lower respiratory tract. We will also assess plasma pulmonary capillary-derived endothelial microparticles (EMPs) as a biomarker for pulmonary apoptosis. Using newly developed mass spectrometry methodologies, we will quantify the oxidant stress of AM, ELF and plasma EMPs, and identify specific oxidized metabolites within each of these compartments. Finally, we will examine the interaction in vitro to tease apart the contribution of each component (AM, ELF, and plasma EMPs) of the interaction.

To assess this concept, the following aims will be addressed:

Specific Aim 1 (n=160). To explore the extent of the oxidant stress in the lower respiratory tract in association with HIV infection and smoking.

Specific Aim 2 (n=160). To evaluate plasma levels of capillary apoptosis and oxidation state of HIV+ nonsmokers and smokers.

Specific Aim 3 (n=160). To examine the interaction of pulmonary capillary endothelium and various oxidant effector components to identify oxidant-vulnerable pathways relevant to the development of new treatment therapies.