Pulmonary hypertension in a murine model of the acquired immunodeficiency syndrome

Rapidly accumulating evidence suggests that a proportion of patients with acquired immunodeficiency syndrome (AIDS) develop hypertensive pulmonary vascular disease reminiscent of primary pulmonary hypertension. As an initial step to explore the link between AIDS and hypertensive pulmonary vascular disease, the present study determined whether pulmonary hypertension is present in a well-characterized murine model of retrovirus-induced immunodeficiency. In agreement with previous reports, mice infected with the LP-BM5 murine leukemia virus developed polyclonal B and T cell activation followed by progressive and severe B and T cell immunodeficiency. At 12 wk postinfection, when persistent immunodeficiency was established, mice were anesthetized, and right ventricular systolic pressure was determined in open-chest, mechanically ventilated animals. Mean right ventricular systolic pressure was 14.7 +/- 1.3 mm Hg in control animals and was increased significantly to 22.5 +/- 3.2 mm Hg in virus-infected mice. Right ventricular hypertrophy was also present in infected mice as evidenced by a 27% increase in the ratio of right to left ventricular weights; there were no group-dependent differences in the left ventricular to total-body weight ratio. Morphometric evaluation indicated that medial thickness in muscularized pulmonary arteries, expressed as a percentage of the external diameter, was 9.6 +/- 0.4% in control lungs and increased to 14.4 +/- 0.5% in lungs from infected animals. Qualitative histopathologic analysis suggested increased perivascular collagen deposition in lungs from infected animals relative to control animals. Unlike AIDS patients with pulmonary hypertension, infected mice did not exhibit plexiform lesions or intimal fibrosis of the pulmonary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)