Potential beneficial effects of oral administration of isoflavones in patients with chronic mountain sickness

Soy isoflavones (Ifs), which are natural phytoestrogens, have beneficial effects in cardiovascular disease. We have previously shown that genistein, the most active component of Ifs, inhibits pulmonary vascular structural remodeling and right ventricular hypertrophy induced by chronic hypoxia in male Wistar rats. This study aimed to evaluate the effects of Ifs on right ventricular and pulmonary hemodynamics in individuals with chronic mountain sickness (CMS). Twenty-eight male patients living on the Qinghai-Tibetan plateau (5,200 m) who were suffering from CMS were treated orally with Ifs (20 mg, twice daily) for 45 days. Physiological and plasma biochemical indices, hematology and echocardiography were investigated. It was observed that 45 days of treatment with Ifs significantly increased blood oxygen saturation and markedly decreased the CMS score and heart rate (all P<0.05) of the subjects. Following treatment with Ifs, hematocrit (P<0.05), hemoglobin concentration (P<0.01) and plasma levels of malondialdehyde (P<0.05) were significantly decreased, while plasma levels of nitric oxide (P<0.01) and the plasma activity of nitric oxide synthase (P<0.01) and superoxide dismutase (P<0.01) were markedly increased compared with the respective values obtained prior to treatment with Ifs. The echocardiography results showed that Ifs significantly decreased the main pulmonary artery diameter (P<0.05), right ventricular end-diastolic anteroposterior diameter (P<0.01), right ventricular end-diastolic trans diameter (P<0.01), right ventricular anterior wall (P<0.01) and right ventricular outflow tract (P<0.01). These results indicate the potential beneficial effects of Ifs in the reduction of excessive erythrocytosis, the alleviation of oxidative damage and the amelioration of right ventricular index and pulmonary hemodynamics in CMS.