Essential fatty acids, prostaglandins, and respiratory distress syndrome of the newborn

The lungs are a major metabolic site for the synthesis, release, and degradation of prostaglandins. Prostaglandins of the E and F series exert a potent physiological effect on the smooth muscle of blood vessels and the tracheobronchial tree; prostaglandin E dilates while prostaglandin F constricts. Thus, altered prostaglandin metabolism may contribute to the pathophysiology of respiratory distress syndrome (RDS). Twenty-one infants with RDS and ten age and weight-matched controls were studied by analyzing their plasma for prostaglandins and their precursor essential fatty acids. The two groups showed no difference in the essential fatty acid prostaglandin precursors, dihomo-γ-linolenic and arachidonic acids. During the acute phase of RDS, plasma levels of the primary prostaglandins E and F are significantly elevated compared with control values and the ratio of prostaglandin E to prostaglandin F significantly reduced. Prostaglandins E and F returned to control values on recovery from the acute stage of the disease. Two infants with persistent patent ductus arteriosus had significantly elevated prostaglandin E values in their plasma compared with controls. The elevated levels of circulating plasma prostaglandins E and F and the reversal of their ratio during the acute phase of RDS may have adverse pulmonary and multisystem effects.