Association between an angiotensinogen microsatellite marker in children and coronary events in their grandparents

Gene-gene interaction in the RAS system in the predisposition to myocardial infarction in elder population of St. Petersburg (Russia)

The aim of this study was to estimate the frequencies of some DNA polymorphisms of two genes of the renin-angiotensin system (RAS), M235T angiotensinogen gene and insertion-deletion polymorphism in angiotensin-converting enzyme gene, in older (>55 years old) myocardial infarction survival and control groups. For this purpose 198 myocardial infarction (MI) patients and 152 randomly selected healthy persons have been analyzed. We have not found any differences in allele and genotype distribution in the above-mentioned genes for either group. However, statistical research showed a significant increase of double homozygotes IITT in the group of MI patients as compared with those in the control group. In this respect we suggested that gene-gene interaction in the RAS system may be considered to be a predisposing factor for MI development.

Associations of angiotensinogen gene mutations with hypertension and myocardial infarction in a gulf population

To date, the human angiotensinogen (AGT) gene and some of its variants represent the best examples of genetic influences that are involved in the determination of essential hypertension (EH) and associated cardiovascular diseases (CVDs). To assess the value of genotyping AGT in a genetically homogeneous population, we carried out a retrospective, case control study of variants M235T and T174M for putative correlations with CVDs among nationals from the United Arab Emirates (Emirati)--an ethnic group characterized by no alcohol intake and no cigarette smoking. We investigated a sample population of 229 Emirati (119 males and 110 females), comprising groups of controls and patients with clinical diagnoses of EH, left ventricular hypertrophy (LVH), ischaemic heart disease (IHD) and myocardial infarction (MI). M235T and T174M alleles were determined via assays based on the polymerase chain reaction. T174M showed no correlation with any of the four clinical entities included in this study. T235 alleles, however, occurred more frequently in the EH group and less frequently in the group of MI survivors. We also found that T235 allele frequencies decreased with age, indicating that in the Emirati population, T235 alleles are associated with a reduced life span and that this effect could occur through independent mechanisms underlying genetic susceptibilities to both EH and MI.

Association between angiotensin II receptor gene polymorphism and serum angiotensin converting enzyme (SACE) activity in patients with sarcoidosis

BACKGROUND

Serum angiotensin converting enzyme (SACE) is considered to reflect disease activity in sarcoidosis. SACE activity is increased in many patients with active sarcoid lesions. The mechanism for the increased SACE activity in this disease has not been clarified. ACE insertion/deletion (I/D) gene polymorphism has been reported to have an association with SACE levels in sarcoidosis, but no evidence of an association between angiotensin II receptor gene polymorphism and SACE in this disease has been found. A study of the association of angiotensin II receptor gene polymorphisms with sarcoidosis was therefore undertaken.

METHODS

ACE (I/D), angiotensin II type 1 receptor (AGTR1), and angiotensin II type 2 receptor (AGTR2) gene polymorphisms were investigated by polymerase chain reaction (PCR) and SACE levels were measured in three groups of patients: those with sarcoidosis or tuberculosis and normal controls.

RESULTS

There was no difference in allele frequency of AGTR1 and AGTR2 polymorphism among the three groups. Neither AGTR1 nor AGTR2 polymorphisms were associated with sarcoidosis. SACE activity was higher in patients with sarcoidosis with the AGTR1 A/C genotype than in others. However, this tendency was not detected in patients with tuberculosis.

CONCLUSIONS

The AGTR1 allele C is associated with high activity of SACE in patients with sarcoidosis. It is another predisposing factor for high levels of SACE in patients with sarcoidosis and is considered to be an independent factor from the ACE D allele for high levels of SACE in sarcoidosis. This fact could be one of the explanations for the increased SACE activity in sarcoidosis.