Influence of polymorphism of glutathione S-transferase M1 on systolic blood pressure of normotensive individuals

Lymphocyte DNA damage and plasma antioxidant status in Korean subclinical hypertensive patients by glutathione S-transferase polymorphism

BACKGROUND/OBJECTIVES

Glutathione S-transferase (GST) forms a multigene family of phase II detoxification enzymes which are involved in the detoxification of xenobiotics by conjugating substances with glutathione. The aim of this study is to assess the antioxidative status and the degree of DNA damage in the subclinical hypertensive patients in Korea using glutathione S-transferase polymorphisms.

SUBJECTS/METHODS

We examined whether DNA damage and antioxidative status show a difference between GSTM1 or GSTT1 genotype in 227 newly diagnosed, untreated (systolic blood pressure (BP) ≥ 130 mmHg or diastolic BP ≥ 85 mmHg) subclinical hypertensive patients and 130 normotensive subjects (systolic BP < 120 mmHg and diastolic BP < 80 mmHg). From the blood of the subjects, the degree of the DNA damage in lymphocyte, the activities of erythrocyte superoxide dismutase, the catalase, and the glutathione peroxidase, the level of glutathione, plasma total radical-trapping antioxidant potential (TRAP), anti-oxidative vitamins, as well as plasma lipid profiles and conjugated diene (CD) were analyzed.

RESULTS

Of the 227 subjects studied, 68.3% were GSTM1 null genotype and 66.5% were GSTT1 null genotype. GSTM1 null genotype had an increased risk of hypertension (OR: 2.104, CI: 1.38-3.35), but no significant association in GSTT1 null genotype (OR 0.982, CI: 0.62-1.55). No difference in erythrocyte activities of superoxide dismutase, catalase, or glutathione peroxidase, and plasma TRAP, CD, lipid profiles, and GSH levels were observed between GSTM1 or GSTT1 genotype. Plasma levels of α-tocopherol increased significantly in GSTT1 wild genotype (P < 0.05); however, plasma level of β-carotene increased significantly in GSTT1 null genotype (P < 0.01). DNA damage assessed by the Comet assay was significantly higher in GSTM1 null genotype than wild genotype (P < 0.05).

CONCLUSIONS

These results confirm the association between GSTM1 null genotype and risk of hypertension as they suggest that GSTM1 null genotype leads to an increased oxidative stress compared with wild genotype.

The effect of glutathione S-transferase M1 and T1 polymorphisms on blood pressure, blood glucose, and lipid profiles following the supplementation of kale (Brassica oleracea acephala) juice in South Korean subclinical hypertensive patients

BACKGROUND/OBJECTIVES

Glutathione S-transferase (GST) forms a multigene family of phase II detoxification enzymes which are involved in the detoxification of reactive oxygen species. This study examines whether daily supplementation of kale juice can modulate blood pressure (BP), levels of lipid profiles, and blood glucose, and whether this modulation could be affected by the GSTM1 and GSTT1 polymorphisms.

SUBJECTS/METHODS

84 subclinical hypertensive patients showing systolic BP over 130 mmHg or diastolic BP over 85 mmHg received 300 ml/day of kale juice for 6 weeks, and blood samples were collected on 0-week and 6-week in order to evaluate plasma lipid profiles (total cholesterol, triglyceride, HDL-cholesterol, and LDL-cholesterol) and blood glucose.

RESULTS

Systolic and diastolic blood pressure was significantly decreased in all patients regardless of their GSTM1 or GSTT1 polymorphisms after kale juice supplementation. Blood glucose level was decreased only in the GSTM1-present genotype, and plasma lipid profiles showed no difference in both the GSTM1-null and GSTM1-present genotypes. In the case of GSTT1, on the other hand, plasma HDL-C was increased and LDL-C was decreased only in the GSTT1-present type, while blood glucose was decreased only in the GSTT1-null genotype.

CONCLUSIONS

These findings suggest that the supplementation of kale juice affected blood pressure, lipid profiles, and blood glucose in subclinical hypertensive patients depending on their GST genetic polymorphisms, and the improvement of lipid profiles was mainly greater in the GSTT1-present genotype and the decrease of blood glucose was greater in the GSTM1-present or GSTT1-null genotypes.

Therapeutic effect of yoga in patients with hypertension with reference to GST gene polymorphism

BACKGROUND

Hypertension, a chronic medical condition of increased blood pressure, is a serious public health problem. Environmental and genetic risk factors are known to predispose to hypertension. The present study was designed to investigate the association of glutathione S-transferase (GST) gene polymorphism with oxidative stress in hypertensive patients and the possible beneficial effect of yoga on them.

MATERIALS AND METHODS

Sixty (60) hypertensive individuals, between 30 and 60 years of age, were divided into two groups of 30 each. The yoga group was subjected to 50-60 minutes of yogic practices daily for 42 days, while the control group included the remaining 30 age- and sex-matched hypertensive individuals. GST gene polymorphism was analyzed using multiple allele specific polymerase chain reaction, and oxidative stress parameters were assessed biochemically.

RESULTS

Assessment of blood pressure showed a statistically significant though modest reduction (p<0.05) in the yoga group as compared to the control group. Malondialdehyde was observed to be significantly low (p<0.05), while antioxidant capacity in the form of GST showed an increasing trend and ferric-reducing ability of plasma was significantly increased (p<0.05) in the subjects who practiced yoga.

CONCLUSIONS

In conclusion, yoga has been found to decrease blood pressure as well as the levels of oxidative stress in patients with hypertension.

Genetic polymorphisms of glutathione S-transferase T1 (GSTT1) and M1 (GSTM1) in selected populations of Afghanistan

Genetic polymorphisms in genes encoding glutathione S-transferase T1 (GSTT1, a member of class theta) and M1 (GSTM1, a member of class mu) have been defined. Previous studies have revealed that there was significant difference between populations for allelic frequency of several members of GSTs. In order to find the prevalence of null genotypes of GSTM1 and GSTT1 in Afghanis populations the present study was carried out. The total study subjects consisted of 656 unrelated healthy Afghanis refugees living in Fars province (southern Iran). From these 257, 217, 120, and 62 individuals were Pashtuns, Tajiks, Hazaras, and Uzbeks, respectively. Genetic polymorphisms for GSTT1 and GSTM1 were detected by multiplex PCR. The prevalence of null genotype of GSTM1 in Pashtuns, Tajiks, Hazaras, and Uzbeks was 42.4, 48.4, 52.5, and 40.3 %, respectively. There was no significant difference between these populations for the genotypic distribution of the GSTM1 polymorphism (χ(2) = 4.67, df = 3, P = 0.197). The frequency of GSTT1 null genotype in Pashtuns, Tajiks, Hazaras, and Uzbeks was 7.4, 25.3, 25.0, and 29.0 %, respectively. The observed difference between populations for prevalence of GSTT1 null genotype was statistically significant (χ(2) = 35.54, df = 3, P < 0.001). In comparison with European and Asian populations, Afghanistan populations like Iranian populations showed intermediate frequency for GSTT1 and GSTM1 null genotypes.

The role of glutathione S- transferase M1 and T1 gene polymorphisms and oxidative stress-related parameters in Egyptian patients with essential hypertension

BACKGROUND

Essential hypertension is a complex, multifactorial, polygenic disease in which the underlying genetic components remain unknown. Glutathione S-transferase (GST) enzyme is involved in detoxification of reactive oxygen species. This study aimed to investigate GSTM1 and GSTT1 gene polymorphisms in Egyptian essential hypertensive patients and their relationship with oxidative stress-related parameters.

METHODS

The study included 40 newly-diagnosed, untreated, essential hypertensive patients and 40 normotensive subjects. Plasma levels of malondialdehyde (MDA), and nitrate/nitrite and erythrocyte reduced glutathione (GSH), activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione S-transferase (GST) were measured. Genotyping for GSTM1 and GSTT1 was performed.

RESULTS

The frequency of GSTM1+ve/GSTT1+ve in hypertensives (5%) was lower than in normotensives (37.5%).The frequency of GSTM1-ve/GSTT1-ve was elevated in hypertensives (35%) as compared to normotensives (7.5%). Plasma MDA was higher and nitrate/nitrite was lower in hypertensives than in normotensives. Erythrocyte GSH, activities of CAT, SOD, GSH-Px, and GST of hypertensives were lower than normotensives. Moreover, GST activity was lower in subjects with GSTM1-ve/GSTT1-ve than in those with GSTM1+ve/GSTT1+ve. In hypertensives, both systolic and diastolic blood pressures were negatively correlated with activities of CAT, GSH-Px, and GST.

CONCLUSIONS

GSTM1-ve/GSTT1-ve is a potential genetic factor to predict development of essential hypertension and permit early therapeutic intervention. The significant association between blood pressure and oxidative stress-related parameters indicates the pathogenic role of oxidative stress in hypertension. Antioxidants could be useful in the management of essential hypertension to prevent progressive deterioration and target organ damage however, further studies involving long-term clinical trials may help to assess the efficacy of these therapeutic agents.

Glutathione S-transferase genetic polymorphisms (GSTM1, GSTT1 and GSTO2) in three Iranian populations

Genetic polymorphisms in genes encoding glutathione S-transferases M1 (GSTM1; a member of class mu), T1 (GSTT1; a member of class theta) and O2 (GSTO2; a member of class omega) have been defined previously. Studies have revealed that there were significant differences between populations for allelic frequencies of GSTT1, GSTM1 and GSTO2 N412D polymorphisms. To get more insight into the genetic structure of Iranian populations the present study was done on Iranian Georgians living in Frydoonshahr (Isfahan province) and two Persian populations who living in Shiraz (Fars province) and Frydoonshahr. Study subjects consisted of 401 unrelated healthy individuals. From these 121 were Georgians. The remaining subjects were Persians from either Frydoonshahr (n = 34) or Shiraz (n = 246). The genetic polymorphism of GSTT1, GSTM1 and GSTO2 N412D was detected by PCR-based method. The frequency of GSTT1 null genotype in Georgian and Persians of Frydoonshahr and Shiraz was 15.7, 35.2 and 24.8%, respectively. There was significant difference between these populations for the distributions of the GSTT1 genotypes (chi(2) = 7.00, df = 2, P = 0.030). No significant difference was observed between these populations for polymorphisms of GSTM1 (chi(2) = 1.682, df = 2, P = 0.431) and GSTO N142D (chi(2) = 4.622, df = 4, P = 0.328). The prevalence of GSTT1 null genotype in Iranian Georgians showed significant difference with Persians and other Asian countries, but it seems to be similar with the frequency which was reported from European populations.

Genetic polymorphisms of GSTO2, GSTM1, and GSTT1 and risk of gastric cancer

OBJECTIVE

The glutathione S-transferases (GSTs) are a superfamily of proteins that participates in detoxification. The GSTs were dividing into several classes including omega (GSTO), micro (GSTM) and theta (GSTT) classes. In human GSTO2, GSTM1, and GSTT1 are polymorphic. In order to study whether GSTO2, GSTM1, and GSTT1 polymorphisms are associated with increased gastric cancer risk in Iranian patients, the present case-control study was done.

METHODS

Genomic DNA was extracted from peripheral blood of 67 gastric cancer patients and 134 control subjects. The genotyping was performed using PCR-based method. The possible association of gastric cancer with the GSTO2 N142D polymorphism was estimated with assuming additive, dominant, and recessive effect of the variant 142D allele. To investigate whether profiles of GST genotypes are associated with the risk of gastric cancer, we used unconditional logistic regression analysis.

RESULTS

The GSTO2 142D allele in additive, dominant and recessive models was not associated with the risk. Because GSTM1, GSTT1, and GSTO2 genes belong to low-penetrance genes which might be involved in the carcinogenesis, patients and controls without family of cancer in first-degree relatives were also analyzes separately. To investigate whether profiles of GST genotypes are associated with the risk of gastric cancer, we used unconditional logistic regression analysis with GSTM1, GSTT1, and GSTO2 genotypes as predictor factors. The GSTO2 DD genotype was associated with decreased risk as compared to GSTO2 NN genotype (OR = 0.21, 95% CI: 0.05-0.92, P = 0.038).

CONCLUSIONS

Present findings show that GSTO2 DD genotype decreases the risk of gastric cancer in individuals without history of cancer in their first-degree relatives.

Genetic polymorphisms of XRCC1 (at codons 194 and 399) in Shiraz population (Fars province, southern Iran)

OBJECTIVE

Several potential functional polymorphisms in the DNA base excision repair gene X-ray repair cross-complementing group 1 (XRCC1) have been reported. There has been no information on interindividual variability of Arg194Trp and Arg399Gln polymorphisms of XRCC1 in the Iranian population. Due to the association between the polymorphisms of XRCC1 and the risk of some types of cancers, the present study was done.

METHODS

The genetic polymorphisms of XRCC1 were detected by PCR-based method in 707 healthy individuals from Shiraz population, (Fars province, southern Iran).

RESULTS

Considering that there was no statistically significant difference between males and females, the sex groups were pooled. The frequencies of 194Trp and 399Gln alleles were 9.05% and 33.95%, respectively. When both polymorphisms were considered, the linkage-disequilibrium was observed (D' = 0.8986, r(2) = 0.0413, P < 0.00001).

CONCLUSION

The present results indicated that the allelic frequencies in Iranian populations showed intermediate frequencies in comparison with European and other Asian countries.

Molecular genetics of human hypertension

EH (essential hypertension) is a major public health problem in many countries due to its high prevalence and its association with coronary heart disease, stroke, renal disease, peripheral vascular disease and other disorders. Epidemiological studies have demonstrated that EH is heritable. Owing to the fact that blood pressure is controlled by cardiac output and total peripheral resistance, many molecular pathways are believed to be involved in the disease. In this review, recent genetic studies investigating the molecular basis of EH, including different molecular pathways, will be highlighted.