Introduction: People who visit high altitude are exposed to a stressful environment, and many of them suffer from altitude-induced conditions, including high altitude pulmonary edema (HAPE). We investigated the renin angiotensin aldosterone system (RAAS) and the possible association of angiotensin converting enzyme (ACE) insertion/deletion (I/D) gene polymorphism in the development of HAPE in Indian men.
Methods: Subjects were all low-altitude natives: 19 men who developed HAPE within 1-3 d of arrival at 3000 to 3800 m (patients); and 20 age-matched men who did not develop HAPE during a period of a month or more at > or = 3500 m (controls). We recorded the arterial oxygen saturation (Sao2), heart rate (HR), and blood pressure (BP) of both groups and measured their levels of plasma renin activity (PRA), ACE, aldosterone, and serum electrolytes. Polymerase chain reaction was used to investigate a 287 base pair alu repeat sequence I/D polymorphism in the ACE gene.
Results: Compared with controls, patients showed a significantly lower Sao2 and a higher HR. They also had significantly higher plasma PRA, aldosterone, ACE, and serum sodium (Na+) and potassium (K+). No significant difference was observed in ACE I/D allele frequencies.
Discussion: The results suggested that RAAS is involved in the development of HAPE in low-altitude natives, but there is no association of ACE I/D gene polymorphism with HAPE.