Abnormal lipid composition of bronchoalveolar lavage fluid obtained from individuals with AIDS-related lung disease.

Abstract

Surfactant lipids are not only important to the physiologic function of the lungs, but may also influence disease processes like Pneumocystis pneumonia, in which the interaction of host-defense cells with pathogen occurs within the confines of the surfactant-rich alveolar hypophase. In the present studies the lipid profile of bronchoalveolar lavage fluid (BALF) was characterized in subjects with AIDS-related lung diseases including Pneumocystis pneumonia. BALF lipid and total protein measurements were made in 43 subjects with acquired immune deficiency syndrome (AIDS)-related lung disease and compared with those made in 50 normal human immunodeficiency virus (HIV)-seronegative controls. The AIDS patient samples contained significantly greater amounts of total cholesterol, phosphatidylglycerol (PG), and protein than the control samples; in contrast to previous observations in rodent P. carinii infection, no differences were seen in total phospholipid (PL) or phosphatidylcholine (PC) in the two groups. The proportions of several of these lipids were deranged in BALF obtained from the patient group: PG/PL and PC/cholesterol differed significantly from normal samples. In the subset of patients with AIDS-related Pneumocystis pneumonia, no correlation was apparent between discrete BALF lipids and clinical indices reflective of disease severity. Using these measurements to approximate the lipid composition of the alveolar microenvironment in AIDS-related lung disease, we performed experiments in which normal human alveolar macrophages were exposed to exogenous liposomal lipids and then challenged with P. carinii. The ingestion but not binding of P. carinii by macrophages was diminished as a result of lipid exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Phytosterols are present in Pneumocystis carinii

“…It is clear that the regulation of the sterol content of P. carinii is important for understanding the growth of the organism. It may be relevant in this regard that other studies from this laboratory have shown significant increases in the amount of cholesterol of bronchoalveolar lavage from human immunodeficiency virus-positive patients (29).…”

Surfactant protein-A levels increase during Pneumocystis carinii pneumonia in the rat

“…Recent reports analysing the surfactant lipids in BAL from HIV-infected pneumonia patients report either reductions [4,5] or abnormalities in lipid composition in these individuals [6]. A study using the rat model found that although the glucocorticoid treatment markedly elevated surfactant lipid levels, these levels were reduced to less than half of untreated control values when the animals became infected with P. carinii [7].…”

“…We have reported that surfactant-associated protein-A (SP-A) is markedly elevated in bronchoalveolar lavage (BAL) fluid from patients with acquired immune deficiency syndrome (AIDS)-related pneumonias caused by P. carinii [3]. Significant decreases [4,5], or abnormal lipid profiles [6], in surfactant phospholipid levels have recently been reported in BAL from HIV-positive patients. The finding of reduced phospholipids is consistent with experimental observations made in the glucocorticoid-immunosuppressed rat, a model commonly used to study P. carinii pneumonia.…”

Pulmonary surfactant in patients with Pneumocystis pneumonia and acquired immunodeficiency syndrome

“…Infection results in an interstitial inflammatory response and an eosinophilic proteinaceous alveolar exudate. Previous studies on the pulmonary surfactant system in patients with PCP have yielded inconsistent and fragmentary data (13)(14)(15). In those studies, it was suggested that levels of the hydrophilic surfactant proteins SP-A and SP-D are elevated in bronchoalveolar lavage fluids (BALF) from PCP patients and that the phospholipid profile is altered.…”