Angiotensin-I converting enzyme (ACE) is a key regulator of blood pressure, electrolytes and fluid homeostasis through conversion of angiotensin I into angiotensin II. Recently, a genetic polymorphism of the ACE gene, which accounts for 47% of the variation of ACE activity in blood, has been advocated as a biomarker of athletic aptitude. Different methods of analysis and determination of ACE activity in plasma have been used in human and equine research without a consensus of a "gold standard" method. Different methods have often been used interchangeably or cited as being comparable in the existing literature; however, the actual agreement between assays has not been investigated. Therefore, in this study, we evaluated the level of agreement between three different assays using equine plasma obtained from 29 horses. Two spectrophotometric assays using Furylacryloyl-phenylalanyl-glycyl-glycine as substrate and one fluorimetric assay utilizing o-aminobenzoic acid-FRK-(Dnp)P-OH were employed. The results revealed that the measurements from the different assays were not in agreement, indicating that the methods should not be used interchangeably for measurement of equine ACE activity. Rather, a single method of analysis should be adopted to achieve comparable results and critical appraisal of the literature is needed when attempting to compare results obtained from different assays.
Animals ; Enzyme Assays/*methods ; Female ; Fluorometry/*methods ; Horses/blood/genetics/*metabolism ; Male ; Oligopeptides/pharmacology ; Peptidyl-Dipeptidase A/blood/genetics/*metabolism ; Polymorphism, Genetic ; Reference Values ; Spectrophotometry/*methods

OBJECTIVE: To investigate the effect of angiotensin converting enzyme (ACE) in the pathogenesis of preeclampsia. METHODS: A cross-sectional study was conducted with 42 pregnant women in the following categories: 30 cases of preeclampsia (mild preeclampsia, n=15; severe preeclampsia, n=15), and normal pregnancy (control group,n=12). The expression and localization of ACE mRNA in the placenta of the 3 groups were respectively examined by in situ hybridization. Ultraviolet radiation colorimetry was used to detect the activity of ACE in the placenta tissue homogenate and the mothers' serum in the 3 groups. RESULTS: The expression of ACE mRNA was found in the endothelial cells of villus and trophoblasts in the placenta. The positive index of ACE mRNA in the placenta of preeclampsia(3.12+/-0.94) was higher than that in the normal pregnancies(1.65+/-0.67) (P<0.05), and there was significant difference between severe preeclampsia and mild preeclampsia (P<0.05). The levels of ACE activity in the placenta tissue homogenate and the maternal serum of preeclampsia were higher than those in the normal pregnancies (P<0.05), and there was significant difference between severe preeclampsia and mild preeclampsia (P<0.05). The placenta tissue homogenate ACE activity was correlated with ACE activity of the maternal serum (r=0.781,P<0.05). CONCLUSION The expression and activity of local ACE in the placenta tissue may play an important role in preeclampsia and contribute to the development of preeclampsia.
Adult ; Cross-Sectional Studies ; Female ; Humans ; In Situ Hybridization ; Peptidyl-Dipeptidase A ; blood ; genetics ; metabolism ; Placenta ; enzymology ; Pre-Eclampsia ; enzymology ; Pregnancy ; RNA, Messenger ; biosynthesis ; genetics

To study the expression of angiotensin converting enzyme 2 (ACE2) and angiotensin (Ang) 1-7 specific receptor Mas protain in renal blood vessels of metabolic syndrome ( MS) rats and its anti-oxidative effect. A total of 80 male SD rats were divided into four groups: the normal control group (NC, the same volume of normal saline), the MS group (high fat diet), the MS + Astragali Radix group (MS + HQ, 6 g x kg(-1) x d(-1) in gavage) and the MS + Valsartan group (MS + XST, 30 mg x kg(-1) x d(-1) in gavage). After four weeks of intervention, their general indexes, biochemical indexes and blood pressure were measured; plasma and renal tissue Ang II, malondialdehyde (MDA) and superoxide demutase (SOD) levels were measured with radioimmunoassay. The protein expressions of Mas receptor, AT1R, ACE and ACE2 were detected by western blot analysis. According to the result, compared with the NC group, the MS group and the MS + HQ group showed significant increases in systolic and diastolic pressures, body weight, fasting glucose, fasting insulin, triglycerides, free fatty acid and Ang II level of MS rats (P < 0.05). The MS + XST group showed notable decreases in systolic and diastolic pressures than that of the MS group. The MS group showed significant increases in the SOD activity and NO level and decrease in the MDA level after being intervened with Astragali Radix. ACE and AT1R protein expressions in renal tissues of the MS group were higher than that in the NC group, but with lower ACE2 and -Mas receptor expressions (all P < 0.05). Compared with the MS group, the MS + HQ group showed significant increase in Mas receptor expression in renal tissues, whereas the MS + XST group showed notable decrease in AT1R (all P < 0.05). In conclusion, Astragali Radix can increase the Mas receptor expressions in renal tissues, decrease ACE expression and change local Ang II, MDA, NO and SOD in kidneys, so as to protect early damages in renal tissues.
Angiotensin I ; metabolism ; Animals ; Astragalus Plant ; chemistry ; Blood Glucose ; metabolism ; Blood Pressure ; drug effects ; Drugs, Chinese Herbal ; administration & dosage ; Humans ; Kidney ; drug effects ; injuries ; metabolism ; Male ; Malondialdehyde ; metabolism ; Metabolic Syndrome ; drug therapy ; genetics ; metabolism ; physiopathology ; Peptide Fragments ; metabolism ; Peptidyl-Dipeptidase A ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, G-Protein-Coupled ; genetics ; metabolism ; Signal Transduction ; drug effects

OBJECTIVETo investigate the effect of tanshinone II(A) on the expression of different components in the renin-angiotensin system of left ventricles of renal hypertensive rats.

METHODThe renal hypertension model was established in rats by the two-kidney-one-clip (2K1C) method. In the experiment, all of the rats were randomly divided into four groups (n = 15 per group) before the operation: the sham-operated (Sham) group, the hypertensive model (Model) group, the low-dose tanshinone II(A) group and the high-dose tanshinone II(A) group. At 5 week after the renal artery narrowing, the third and fourth groups were administered with 35 mg kg(-1) x d(-1) and 70 mg x kg(-1) x d(-1) of tanshinone II(A), respectively. The blood pressure in rats was determined by the standard tail-cuff method in each week after the operation. After the drug treatment for 8 weeks, all the rats were put to death, and their left ventricles were separated to determine the ratio of left ventricle weight to body weight (LVW/BW), the myocardial collagen content, and the expressions of different components in myocardial RAS, including angiotensin converting enzyme (ACE), angiotensin converting enzyme 2 (ACE2), angiotensin 1-type receptor (AT1R), Mas receptor mRNA expression and angiotensin II (Ang II) and angiotensin (1-7) [Ang (1-7)] content.

RESULTCompared with the sham group, the hypertensive model group exhibited a markable increase in the content of Ang II and Ang (1-7) and the mRNA expressions of ACE, ACE2, AT1R and Mas (P < 0.01). However, the treatment with tanshinone II(A) showed the does dependence, inhibited left ventricle hypertrophy, decreased myocardial Ang II content and the mRNA expression of ACE and AT, R in renal hypertensive rats (P < 0. 01) , further increased the myocardial Ang (1-7) content and the mRNA expression of ACE2 and Mas (P < 0.01) , but without any change in the blood pressure of hypertensive rats.

CONCLUSIONThe treatment with tanshinone II(A) could inhibit left ventricle hypertrophy of renal hypertensive rats. Its mechanism may be partially related to the expression of different components in the renin-angiotensin system for regulating myocardial tissues.

Angiotensin I ; genetics ; metabolism ; Angiotensin II ; genetics ; metabolism ; Animals ; Blood Pressure ; drug effects ; Diterpenes, Abietane ; administration & dosage ; Heart Ventricles ; drug effects ; metabolism ; Humans ; Hypertension ; drug therapy ; genetics ; metabolism ; physiopathology ; Male ; Peptide Fragments ; genetics ; metabolism ; Peptidyl-Dipeptidase A ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Renin ; genetics ; metabolism ; Renin-Angiotensin System ; drug effects

OBJECTIVETo investigate the effect of astragaloside IV (As IV) on the activation of rennin-angiotensin system in rats with pressure-overload induced cardiac hypertrophy.

METHODLeft ventricle hypertrophy was induced by abdominal aorta banding between bilateral renal aortas for 12 weeks. Rats were given astragaloside IV 1.0 mg x kg(-1) and 3.3 mg x kg(-1) for 12 weeks, respectively. After treatment, the left ventricular mass index (LVMI)was calculated by morphometry methods. Plasma and cardiac tissue angiotensin II, and plasma aldosterone were measured by ELISA method. Gene expressions of ACE, AT1 and AT2 in cardiac tissue were detected by real time PCR. Protein expressions of AT1 and AT2 in cardiac tissue were detected by Western blot.

RESULTCompared with model rats, LVMI was decreased by astragaloside IV treatment. Biochemical results indicated that the contents of angiotensin II in plasma and cardiac tissue as well as aldosterone in plasma were all increased in abdominal aorta banding rats comparing with sham-operated rats, then, decreased by astragaloside IV treatment. Gene expressions of cardiac ACE was downregulated by astragaloside IV, however, gene and protein expressions of cardiac AT2 were upregulated by astragaloside IV. Both elevated gene and protein expressions of AT1 were not attenuated by astragaloside IV.

CONCLUSIONExcessive activated rennin-angiotensin system in rats with pressure-overload induced cardiac hypertrophy is inhibited by astragaloside IV treatment.

Aldosterone ; blood ; Angiotensin II ; blood ; metabolism ; Animals ; Blood Pressure ; physiology ; Cardiomegaly ; drug therapy ; Enzyme-Linked Immunosorbent Assay ; Hypertrophy, Left Ventricular ; drug therapy ; metabolism ; Male ; Peptidyl-Dipeptidase A ; genetics ; Polymerase Chain Reaction ; Rats ; Rats, Sprague-Dawley ; Receptor, Angiotensin, Type 1 ; genetics ; Receptor, Angiotensin, Type 2 ; genetics ; Renin-Angiotensin System ; drug effects ; Saponins ; therapeutic use ; Triterpenes ; therapeutic use