Hydrogen sulfide system in the pathogenesis of renovascular hypertension in rats

Objective To investigate the role of hydrogen sulfide(H_(2)S)synthases/H_(2)S pathway in the pathogenesis of renovascular hypertension.Methods Wistar rats were subdivided into 4 groups:(1)2-kidney,1-clip(2K-1C group,n=7),(2)control(n=7),(3)sham(n=7),and(4)2K-1C plus sodium hydrosulfide(NaHS)(NaHS-treated group,n=7).The systolic blood pressure(SBP)was measured by a tail-cuff method using a pulse transducer once a week.Four weeks later,all rats were killed and the concentration of plasma hydrogen sulfide(H_(2)S),the activity of the H_(2)S synthases in the kidneys on both sides,the plasma angiotensinⅡconcentration,and the left-to-whole heart weight ratio were measured.Results The SBP was significantly increased in the 2K-1C group(185.4±14.0mmHg)comparing with those in the sham group(112.9±6.5mmHg,,or the NaHS-treated group(134.8±9.5mmHg))(both P<0.01).At 4 weeks,the angiotensinⅡconcentration in the plasma was increased in the 2K-1C and NaHS-treated group,comparing with the control and the sham group(306.92±7.03 pg/ml and 240.73±13.22 pg/ml vs 122.6±25.49 pg/ml and 125.95±10.55 pg/ml,respectively,both P<0.05).The plasma H_(2)S concentration and the activity of H_(2)S synthases in the left kidney were decreased in the 2K-1C group comparing with those in the sham and the control groups.There was no difference of the activity of the H_(2)S synthases in the right kidneys among the 4 groups.The left-to-whole heart weight ratio was increased in the 2K-1C and the NaHS-treated group camparing with that in the sham and natural control groups.Conclusions Dysfunction of the H_(2)S synthases/H_(2)S pathway was involved in the 2K-1C-induced renovascular hypertension in rat.Exogenous administration of H_(2)S donor can attenuate the development of hypertension.These findings suggest that the H_(2)S synthases/H_(2)S pathway participates in the pathogenesis of renovascular hypertension.

Cardiovascular and cerebrovascular outcomes in elderly hypertensive patients treated with either ARB or ACEI

Background Although angiotensin converting enzyme inhibitors （ACEI） and angiotensin receptor blockers （ARB） are equally important in the treatment of hypertension, there is less evidence whether they have equal cardiovascular and cerebrovascular protective effects, especially in elder hypertensive patients. This study aims to clarify this unresolved issue. Methods This cross-sectional study included clinical data on 933 aged male patients with hypertension who received either an ARB or ACEI for more than two months between January 2007 and May 2011. The primary outcome was the composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke. The secondary endpoints were unstable angina, new atrial fibrillation, and transient ischemic attack. Results The median follow-up time was 24 months. Age, drug types, cerebral infarction history, renal dysfunction history were the independent predictors of the primary endpoint. The risk of an occurrence of a primary endpoint event was higher in the ARB group than the ACEI group [P = 0.037, hazard ratios （HR）： 2.124, 95% confidence interval （95% CI）： 1.048-4.306]. The Kaplan-Meier method also suggests that the rate of primary endpoint occurrence was higher in the ARB group than the ACEI group （P = 0.04）. In regard to the secondary endpoints, there were no significant differences between the two treatment arms （P = 0.137, HR： 1.454, 95% CI： 0.888-2.380）. Patient age and coronary heart disease history were independent predictors of the secondary endpoint. Conclusion ACEI were more effective than ARB in reducing cardiovascular and cerebrovascular morbidity and mortality in aged patients with hypertension.

GRK 2 level in peripheral blood lymphocytes of elderly patients with acute myocardial infarction

Objective To investigate the G protein-coupled receptor kinase 2 (GRK 2) level in peripheral blood lymphocytes with cardiac func-tion in elderly patients with acute myocardial infarction. Methods This study enrolled 40 patients with acute ST-segment elevation myo-cardial infarction (STEMI) and 40 patients with unstable angina. All patients were 65 years or older. Cardiac function was evaluated by echocardiography, and the GRK 2 level in peripheral blood lymphocytes was measured. Patients with STEMI were followed up for 2 years. Results The GRK 2 level in peripheral blood lymphocytes was significantly higher in patients with STEMI than in patients with unstable angina, and was negatively correlated with left ventricular ejection fraction, cardiac output, stroke volume, and left ventricular fractional shortening. The GRK 2 level was significantly elevated in some patients with acute STEMI and poor cardiac function. Conclusions In-creased GRK 2 level in patients with acute STEMI may contribute to poor myocardial systolic function and myocardial remodeling. Meas-urement of the GRK 2 level in peripheral blood lymphocytes may assist in the evaluation of cardiac function and myocardial remodeling in elderly patients with acute STEMI.