Chymase gene locus is not associated with myocardial infarction and is not linked to heart size or blood pressure

Association between SNP rs1800875, serum chymase and immunoglobulin E levels in patients with coronary heart disease

OBJECTIVE

The gene for mast cell chymase (CMA1) is an ideal candidate for investigating the genetic predisposition to coronary heart disease (CHD), as activated mast cells have been found to be present in a greater proportion in the shoulder region of atheroma than in normal coronary intimae. Previous studies have indicated that CMA1 promoter polymorphism rs1800875 may be involved in regulating immunoglobulin E (IgE) levels in patients with eczema, and it is associated with the progression of immunoglobulin A nephropathy.

METHODS

The association between single nucleotide polymorphism (SNP) rs1800875, serum chymase, and serum IgE levels was examined in 175 CHD subjects and 95 non-CHD subjects.

RESULTS

Statistical analysis indicated no significant difference in allele frequency between CHD and non-CHD. However, a significant association was found between CMA1 genotypes and total IgE levels in CHD subjects. Meanwhile, crossover analysis revealed that, in GG homozygotes, CHD risk was nearly six times higher in those with IgE (U/ml) level <2.58 (natural logarithm conversion), while no association was found with chymase level.

CONCLUSIONS

Polymorphism rs1800875 of CMA1 may be associated with serum IgE level in CHD subjects, but not with chymase level in both groups. In GG homozygotes, high IgE level is a protective factor against coronary disease.

Influences of chymase and angiotensin I-converting enzyme gene polymorphisms on gastric cancer risks in Japan

BACKGROUNDS AND AIMS

The renin-angiotensin system plays an important role in homeostasis. Angiotensin II, which is generated by chymase and angiotensin I-converting enzyme (ACE), controls blood pressure as well as angiogenesis and cell proliferation. The aim of this study was to clarify the association of the chymase gene (CMA/B) and ACE polymorphisms with susceptibility to gastric cancer and peptic ulcer.

METHODS

We assessed CMA/B A/G and ACE insertion/deletion (I/D) polymorphisms in H. pylori-positive gastric cancers (n = 119), gastric ulcers (n = 127), and duodenal ulcers (n = 105), and controls (n = 294) consisting of H. pylori-positive gastritis alone (n = 162) and H. pylori-negative subjects (n = 132) by PCR methods.

RESULTS

In CMA/B polymorphism, the age- and sex-adjusted odds ratios (OR) of A/A and A/G genotypes relative to the G/G genotype for gastric cancer risk were 7.115 (95% confidence interval, 1.818-27.845) and 1.956 (95% confidence interval, 1.137-3.366), respectively. There was an increased risk for gastric ulcer in the A/A genotype (OR, 3.450; 1.086-10.960). However, there was no association between ACE polymorphism and susceptibility to gastric cancer and peptic ulcer. In allele combination analysis of CMA/B and ACE polymorphisms, the A/I allele combinations (CMA/B G/A or A/A and ACE I/I genotype) significantly increased the risk of gastric cancer development (OR, 4.749, 2.050-11.001) compared with the G/I allele combinations (CMA/B G/G and ACE I/I genotype).

CONCLUSIONS

The CMA/B polymorphism was associated with an increased risk for gastric cancer and gastric ulcer development. The genotyping test of the renin-angiotensin system could be useful for the screening of individuals with higher risks of gastric cancer and gastric ulcer.

Analysis of several hundred genetic polymorphisms may improve assessment of the individual genetic burden for coronary artery disease

BACKGROUND: Single polymorphisms of different genes have been associated with coronary artery disease (CAD). The aim of this study was to evaluate the benefit of analyzing multiple genetic polymorphisms as a compound unit to assess the individual genetic burden for CAD. METHODS AND RESULTS: The study population consisted of 100 case patients with, and 100 control patients without, angiographically proven CAD. The patients were matched for age, sex, and numbers of standard cardiac risk factors. Sixteen different genetic polymorphisms were analyzed using polymerase chain reaction-based technologies. None of these polymorphisms showed a significant difference in the allele frequency between case and control patients. Eight genes with a higher allele frequency in the case group (delta allele frequency >0.05) were defined as risk alleles (RA) and subsequently tested as a compound unit. A risk stratification for 64.5% of all patients was possible when eight genes with their 16 RA were included in the analysis. With more than eight RA per individual, the odds ratio for developing CAD was 3.21 (95% CI 1.77-5.82, P<0.001). However, there was still an overlap in the number of RA in case and control patients. A computer simulation estimated that more than 200 polymorphisms were needed for a reasonable genetic discrimination for patients at risk for CAD. CONCLUSIONS: An increasing number of risk alleles are associated with an elevated risk for CAD. An analysis of multiple polymorphisms, some several hundred, each with a small impact, may allow improved assessment of the individual genetic burden for CAD. Larger studies are needed to prove this hypothesis.

[Genes and coronary heart disease]

The causes of atherosclerotic cardiovascular disease have been intensely scrutinized for the last few decades. Since the classic risk factors have been found to be incomplete predictors of the disease, additional risk factors based on molecular genetics are now being sought. Polymorphisms are gene variations that have only modest effects on the function of coded proteins or enzymes. However, they are common and may be risk factors in the presence of environmental risk factors (cholesterol, stress, tobacco). Recent advances in molecular biology have made it possible to detect numerous polymorphisms that might have a detrimental effect on vascular biology, suggesting the hypothesis that multiple polymorphisms in the presence of environmental factors could act synergistically in the pathogenesis of atherosclerosis and coronary heart disease, which are typically polygenic and multifactorial diseases. In this review, the current status of our knowledge of polymorphisms and mutations potentially implicated in the mechanisms of coronary artery disease is discussed. Genotype/phenotype, gene-gene, and gene-environmental interactions related to lipid metabolism, the renin-angiotensin-aldosterone and adrenergic systems, insulin resistance, oxidative stress and endothelial function, inflammation and thrombosis are analyzed. Individual coronary risk might be related to the presence of a critical accumulation detrimental polymorphisms.

Association of a mast cell chymase gene variant with HDL cholesterol, but not with blood pressure in the Ohasama study

Two enzymes, chymase and angiotensin converting enzyme (ACE), are involved in the production of angiotensin II. Our previous study revealed the male-specific effect of the ACE DD genotype on the risk for hypertension, but the genetic role of chymase remains unclear. In the present study, we report the results of an association study involving 1,046 subjects recruited from a general population in Ohasama, a rural community in the northern part of Japan. In addition to casual blood pressure (casual BP) measurement, home BP measurements were obtained from all participants. There were no differences in either home or casual BP values according to G3255A polymorphism of the mast cell chymase gene (MCC). HDL cholesterol level was significantly higher among carriers of the A3255 allele (p<0.04). After adjustment for confounding factors, the A3255 allele was still shown to have an effect on HDL cholesterol metabolism (p<0.03). Multiple regression analysis showed that MCC polymorphism was significantly and independently related to serum HDL cholesterol level. In conclusion, G3255A polymorphism of MCC is not directly associated with blood pressure but may modulate the prevalence of hypertensive complications via alteration of lipid metabolism.

A chymase gene variant is associated with atherosclerosis in venous coronary artery bypass grafts

BACKGROUND

Angiotensin II is known to stimulate proliferation of fibroblasts and smooth muscle cells and enhance the atherosclerotic process in native coronary arteries. The impact of genetic polymorphisms of the renin-angiotensin-aldosterone system on coronary bypass graft degeneration is unknown.

METHODS

We examined polymorphisms of four genes (AGTR1, CYP11B2, ACE, CMA) in 101 patients who had follow-up coronary angiography due to symptoms 88 +/- 52 months after coronary artery bypass graft surgery. Bypass degeneration was determined with quantitative coronary angiography and an adjusted Gensini score.

RESULTS

Homozygosity for the G allele of the CMA-1905 polymorphism was associated with a higher degree of bypass degeneration (Bypass Gensini score CMA AA 21.4 +/- 39; AG 24.2 +/- 39.8; GG 27.8 +/- 42.3; NS-time adjusted Gensini bypass scores CMA AA 0.25 +/- 0.68; AG 0.57 +/- 1.82; GG 3.25 +/- 13.2; P = 0.005). No association could be detected for the AGTR1, CYP11B2 or ACE polymorphism.

CONCLUSION

The CMA allele G is a genetic risk factor for atherosclerosis in venous coronary artery bypass grafts. Its importance has to be shown in further studies. Other polymorphisms of the renin-angiotensin-aldosterone system do not seem to play a role in bypass degeneration.