Increased angiotensin II in ascites during severe ovarian hyperstimulation syndrome: role of early pregnancy and ovarian gonadotropin stimulation

Objective: To investigate the implications of the ovarian renin-angiotensin system (RAS) in the pathophysiology of the ovarian hyperstimulation syndrome (OHSS) in relation to gonadotropin stimulation and early pregnancy. Design: A controlled clinical study comparing blood and simultaneously sampled peritoneal fluid (PF) from patients with severe OHSS and from controls without OHSS. Setting: University Hospitals. Patient(s): Eleven patients with severe DHSS, 8 patients with ascites of other origin, 9 patients with a first-trimester pregnancy, and 15 patients stimulated with gonadotropins for IVF. Main outcome measure(s): Angiotensin II immunoreactivity was measured in blood and PF and analyzed by high-performance liquid chromatography (HPLC) in ascites from OHSS. Result(s): Angiotensin II immunoreactivity (pg/mL; mean ± SE) was highest in the ascites from pregnant OHSS (1,669 ± 418), reaching levels 5 times higher than in the plasma (331 ± 61) and 100 times higher than in control ascites (17 ± 6.7). Angiotensin II immunoreactivity was elevated in the PF during early pregnancy (211 ± 68) and after gonadotropin stimulation (244 ± 41) and was higher than in the plasma in both groups. Analysis by HPLC showed that the majority of Ang II immunoreactivity in the ascites of OHSS was because of true Ang II. Conclusion(s): Severe forms of OHSS, especially those associated with pregnancy, are consistently characterized by huge concentrations of Ang II immunoreactivity in the ascites, proved to be true Ang II by HPLC analysis. This may be due to the synergistic effects of exogenous and endogenous hCG on the ovarian RAS.