Endoxin:a major factor regulating cardiovascular system.

Endoxin is a factor with a digitalis-like biological activity. It is a Na+ pump inhibitor and may be an endogenous medium of digitalis receptor. There are abnormal plasma levels of endoxin in some pathophysiologic states such as hypertension, acute myocardial infarction, arrhythmia, heart failure, etc. Some studies have demonstrated that the abnormal endoxin levels may be implicated in pathogenesis of these diseases or pathophysiologic process involved. Therefore, to clarify the effects of endoxin has much significance in understanding pathogenesis, prevention and treatment of hypertension and other cardiovascular diseases.

Effect of anti-digoxin antiserum on endoxin and membrane ATPase activity in hypoxia-reoxygenation induced myocardial injury.

AIM: To evaluate the protective effect of anti-digoxin antiserum on hypoxia-reoxygenation induced injured myocardium and its mechanism. METHODS: Anti-digoxin antiserum of different concentrations was used, its effect on endoxin and ATPase activity in cell membrane in hypoxia-reoxygenation myocardium model was observed. RESULTS: The level of endoxin was remarkably higher, ATPase activities in cell membrane were remarkably lower in hypoxic group and hypoxia-reoxygenation injury group than those of normal group; anti-digoxin antiserum could resume ATPase activity in a concentration-dependent manner. CONCLUSION: Rise of endoxin was the molecular biological basis of myocardial damage during myocardial hypoxia-reoxygenation. Anti-digoxin antiserum had lessened myocardial injury and had a protective effect on hypoxia-reoxygenation myocardium by antagonizing effect of endoxin.

Effect of combination of valsartan with benazepril on blood pressure and left ventricular hypertrophy in SHR.

AIM: To evaluate the antihypertensive efficacy of angiotensin converting enzyme inhibitor (ACEI) benazepril in combination with AT1 receptor antagonist valsartan and their effect on left ventricular hypertrophy, renin angiotensin aldosterone system (RAAS) and endoxin in spontaneously hypertensive rat (SHR). METHODS: WKY control group (n = 6) and other 4 groups consisted of 24 SHR (14-week-old, male, n = 6): SHR control group, benazepril group, valsartan group, and combination drug therapy group. Systolic blood pressure (SBP) of SHR was measured at the beginning and at the end of 2, 4, 6, and 8 wk of drug intervention. Morphometric determination, renin activities, angiotensin II (Ang II), endoxin, and ATPase activity analysis were performed at the end of 8 week of drug intervention. RESULTS: SBP, ratio of left ventricular mass (LVM), body weight (BW) (LVM/BW), and transverse diameter of myocardial cell (TDM) of SHR were remarkably decreased after drug intervention, and this decrease was most remarkable in the combination drug therapy group. Renin activities of plasma and myocardium were remarkably increased in drug intervention groups. The levels of Ang II in plasma and myocardium were remarkably increased in valsartan group, decreased in benazepril group and combination drug therapy group. Na(+)-K(+)-ATPase activities in myocardium were remarkably increased and the level of endoxin in myocardium were remarkably decreased as SBP decreased after drug intervention. CONCLUSION: Both benazepril and valsartan can decrease SBP of SHR, and cause regression of ventricular hypertrophy. The efficacy of combination drug therapy group is most remarkable among all groups and avoids the side effects of induction of high Ang II levels in plasma and myocardium caused by long-term use of valsartan alone.

[Effect of theo-polyphenols on oxygen free radicals and hemorrheology in patients with essential hypertension].

OBJECTIVE: To observe the effect of theo-polyphenols (TP) on oxygen free radicals and hemorrheology in patients with essential hypertension. METHODS: Hemorheology as well as oxygen free radical of 38 patients were determined before and after TP treatment. RESULTS: TP markedly increased RBC-SOD activity, reduced the level of serum MDA, the whole blood viscosity, plasma viscosity and the level of plasma fibrinogen. The efficacy of TP was higher than that of aspirin. CONCLUSION: The TP had remarkable effects of anti-oxygen free radicals, and could improve hemorheology.

[Changes in serum endogenous digitalis-like factor concentration in patients with renal impairment].

Measurement of serum endogenous digitalis-like factor (EDF) concentration was carried out in 58 patients with renal impairment with radioimmunoassay. The results showed that serum EDF concentration in patients with renal impairment was markedly higher than that of normal cases. The serum EDF concentration was significantly elevated with decrease of renal function and was positively correlated with the levels of BUN and blood creatinine. The serum EDF concentration in patients with primary and secondary renal impairment was of no difference. It was found that the difference between patients with and without hypertension was statistically significant. The serum EDF concentrations were markedly decreased after hemodialysis but still higher than those of normal cases.