Impaired lipid metabolism in idiopathic pulmonary alveolar proteinosis

Background: It is well known that lipids abnormally accumulate in the alveoli during idiopathic pulmonary alveolar proteinosis (PAP). It is unclear, however, whether lipids also abnormally accumulate in serum. This study investigated the serum lipid panels in idiopathic PAP patients and explored the relationships between serum levels and the severity of idiopathic PAP. Methods and Results: Clinical data including the level of serum lipids were evaluated in 33 non-diabetic idiopathic PAP patients and 157 healthy volunteers. Serum levels of triglyceride were higher in PAP patients than in healthy subjects (median: 192.00 mg/dl (P-25: 104.36, P-75: 219.00) vs 119.56 mg/dl (P-25: 78.81, P-75: 193.03), P < 0.05), while high-density lipoprotein cholesterol (HDL-C) levels were lower in patients than in the control group (42.50 +/- 10.30 vs 51.34 +/- 12.06 mg/dl, P < 0.01). Forced expiratory volume in one second and forced vital capacity in hypertriglyceridemia patients were lower than those in patients with normal triglyceride. Serum LDL-C and HDL-C ratio correlated negatively with PaO2 (r = 0.403, P < 0.05) and positively with lactate dehydrogenase (r = 0.381, P < 0.05). Conclusions: PAP associates with high triglyceride and low HDL levels in the serum, and these lipids provide potential intervention strategy for treatment.