[Effect of captopril on aqueous levels of angiotensin II in diabetic patients]

ABSTRACT

To determine whether angiotensin II levels in aqueous humor is related to diabetes mellitus and to evaluate the effect of captopril. In a case-control study, aqueous humor samples were obtained during cataract surgery from 58 eyes of 58 patients, of which 37 were diabetic. From these latter subjects, 16 had taken captopril [captopril group] and 21 had not taken nay angiotensin converting enzyme [ACE] inhibitor [non-captopril group]. Angiotensin level was assessed by radimmunoassay. Severity of macular edema was evaluated by clinical examination after surgery. Mann Whitey U test was used to assess the statistical difference of mean angiotensin II and Hb AIIC levels between the groups and Spearman's rank-order correlation coefficient was used to evaluate correlation between aqueous levels of angiotensin II and of macular edema. The aqueous levels of angiotensin II was significantly higher in diabetic patients [31.0 +/- 7.3 pg/ml] compared to non-diabetics [6.28 +/- 2.8 pg/ml]. [P<0.0001] Aqueous concentration of angiotensin II in the captopril group [16.3 +/- 6.5 ug/ml] was significantly lower than in the non-captopril group [75.73 +/- 9.36]. [P<0.0003] Severity of macular edema was significantly lower in the captopril group as compared to the non-captopril group such that 68.75% of the captopril groups vs 33.3% of the non-captopril group had macular edema [P<0.005]. These finding suggest that the aqueous level of angiotensin II is significantly correlated with the severity of macular edema and may have a role in pathogenesis of macular edema in diabetic patients. It seems that modulation of the rennin-angiotensin system may become a very important target for medical treatment in patients with diabetic macular edema