Association of Polymorphisms in Angiotensin-converting Enzyme and Type 1 Angiotensin Ⅱ Receptor Genes with Coronary Heart Disease and the Severity of Coronary Artery Stenosis

To explore the relation of angiotensin-converting enzyme （ACE） and angiotensin Ⅱ type 1 receptor （AT1R） gene polymorphism with coronary heart disease （CHD） and the severity of coronary artery stenosis, 130 CHD patients who underwent coronary angiography were examined for the number of affected coronary vessels （≥75% stenosis） and coronary Jeopardy score. The insertion/deletion of ACE gene polymorphism and AT1R gene polymorphism （an A→C transversion at nucleotide position 1166） were detected by using polymerase chain reaction （PCR） and restriction fragment length polymorphism （RFLP） in CHD patients and 90 healthy serving as controls. The resuits showed that DD genotype and of ACE were more frequent in CHD patients than that in control group （38.5% vs 14.4%, P〈0.001）. The frequency of the ATIR A/C genotypes did not differ between the patients and the controls （10% vs 13.1%, P〉0.05）. The relative risk associated with the ACE-DD was increased by AT1R-AC genotype. Neither the number of affected coronary vessels nor the coronary score differed among the ACE I/D genotypes （P〉0.05）. But the number of affected coronary vessels and the coronary score were significantly greater in the patients with the AT1R-AC genotype than in those with the AA genotype （P〈0.05）. In conclusion, DD genotype may be risk factor for CHD and MI in Chinese people, and is not responsible for the development of the coronary artery stenosis. The AT1R-C allele may increase the relative risk associated with the ACE-DD genotype, and may be involved in the development of the stenosis of coronary artery.

Neuronal apoptosis and interleukin 1-beta converting enzyme expression in the frontal cortex and hippocampus of mice with ischemia/reperfusion injury

BACKGROUND： Interleukin 1β-converting enzyme （ICE） gene expression can induce neuronal apoptosis. However, the dynamic changes in ICE gene expression and its effects on neuronal apoptosis under cerebral ischemia/reperfusion conditions remain unclear. OBJECTIVE： To observe neuronal apoptosis and changes in ICE gene expression in the frontal cortex and hippocampus following ischemia/reperfusion injury. DESIGN, TIME AND SETTING： A randomized, controlled animal study was conducted at the Laboratory of Experimental Animal Center, the Second Hospital of Jilin University and Central Laboratory, the Second Hospital of Jilin University, China, from November 2008 to September 2009. MATERIALS： The ICE gene primer sequence （TaKaPa Co., Dalian, China）, FACScan Flow cytometer （Becton Dickinson, Franklin Lakes, N J, USA）, and Perkin Elmer GeneAmp PCR system 2400 （Perkin Elmer, Waltham, MA, USA） were used in this study. METHODS： A total of 45 healthy, adult, male, Kunming mice were randomly assigned to normal control （n = 5）, sham surgery （n = 5）, and model （n = 35） groups. The mice in the model group were equally and randomly subdivided into seven subgroups according to various reperfusion time points （1 hour, 1,3, 7, 14, 28, and 42 days）. Animal models of ischemia/reperfusion injury were established by bilateral carotid artery ligation in the model group. The mice in the sham surgery group only received saline perfusion and surgery for carotid artery exposure. MAIN OUTCOME MEASURES： Neuronal apoptosis in the frontal cortex and hippocampus of mice was measured using flow cytometry. The time course of ICE mRNA levels in the frontal cortex and hippocampus were quantified using reverse transcription-polymerase chain reaction. RESULTS： Neuronal apoptosis in the frontal cortex and hippocampus peaked at 3 days following ischemia/reperfusion injury （P 〈 0.05）. ICE mRNA expression increased in the frontal cortex at 1 day following ischemia/reperfusion injury （P 〈 0.05）, decreased at 3 days, and then peaked at 14 days （P 〈 0.05）. ICE mRNA expression increased in the hippocampus at 3 days following ischemia/reperfusion injury （P 〈 0.05）, peaked at 7 days （P 〈 0.05）, and then decreased gradually to normal levels at 28 days. CONCLUSION： Neuronal apoptosis peaked at 3 days following ischemia/reperfusion injury, and both apoptosis and ICE mRNA levels remained high for 2 weeks after injury. Early apoptosis may result from increased ICE mRNA expression.

Inhibitory mechanism of angiotensin-converting enzyme inhibitory peptides from black tea

The aim of this work is to discover the inhibitory mechanism of tea peptides and to analyse the affinities between the peptides and the angiotensin-converting enzyme(ACE)as well as the stability of the complexes using in vitro and in silico methods.Four peptide sequences identified from tea,namely peptides I,II,III,and IV,were used to examine ACE inhibition and kinetics.The half maximal inhibitory concentration(IC_(50))values of the four peptides were(210.03±18.29),(178.91±5.18),(196.31±2.87),and(121.11±3.38)μmol/L,respectively.The results of Lineweaver-Burk plots showed that peptides I,II,and IV inhibited ACE activity in an uncompetitive manner,which requires the presence of substrate.Peptide III inhibited ACE in a noncompetitive manner,for which the presence of substrate is not necessary.The docking simulations showed that the four peptides did not bind to the active sites of ACE,indicating that the four peptides are allosteric inhibitors.The binding free energies calculated from molecular dynamic(MD)simulation were-72.47,-42.20,-52.10,and-67.14 kcal/mol(1 kcal=4.186 kJ),r espectively.The lower IC_(50)value of peptide IV may be attributed to its stability when docking with ACE and changes in the flexibility and unfolding of ACE.These four bioactive peptides with ACE inhibitory ability can be incorporated into novel functional ingredients of black tea.