C677T methylenetetrahydrofolate reductase gene polymorphism as a risk factor involved in venous thromboembolism: a population-based case-control study

Exploring the correlation between homocysteine, red blood cell folate and MTHFRC677T genotypes with female infertility

Aim: To investigate the association between serum homocysteine (HCY) levels, red blood cell folate (RCF) levels, methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and infertility.Materials & methods: Serum HCY and RCF levels and C677T polymorphism of MTHFR gene were analyzed in 149 infertile patients and 223 women of normal reproductive age with healthy childbirth history.Results: The HCY level of MTHFR C677T TT genotype infertility patients was higher than that of women of normal reproductive age, while the RCF level was not significantly different between the two groups.Conclusion: Serum HCY levels increased in infertility patients, and the MTHFR C677T TT genotype in childbearing-aged women are associated with a higher risk of infertility. The results showed that HCY level and MTHFR C677T genotype were closely related to infertility.

Construction and optimization of a polygenic risk model for venous thromboembolism in the Chinese population

BACKGROUND

Venous thromboembolism (VTE) has both environmental and genetic risk factors. It is regulated by polygenes and multisites. The polygenic risk score (PRS) has been widely used because any single genetic biomarker failed to accurately predict the genetic risk of VTE. However, no polygenic risk model has been proposed for VTE in the Chinese population. Thus, we aimed to construct a PRS model for the first episode of VTE in the Chinese population.

METHODS

First, single nucleotide polymorphisms (SNPs) associated with VTE in genome-wide association studies, meta-analyses, and candidate gene studies were screened as variables for the PRS. The logarithm of the odds ratio was used to weight the variables. Second, a training set with simulated data from 1000 cases of VTE and 1000 controls was created with different genotypes and frequencies. Finally, we calculated the area under the receiver operating characteristic curve (AUC) to evaluate the discriminatory ability of the PRS model.

RESULTS

We screened 53 SNPs potentially associated with the first episode of VTE in the Chinese population. The AUC of the PRS-53 model (containing 53 SNPs) was 0.748 (95% confidence interval, 0.727-0.770) in the training set. From the largest weight to the smallest weight, SNPs were incrementally added to the model to calculate the AUC for model optimization. The AUC of the PRS-10 model (containing 10 SNPs) was 0.718 (95% confidence interval, 0.696-0.740), with no statistically significant difference from the AUC for the PRS-53 model.

CONCLUSIONS

The PRS-10 and PRS-53 models showed similar predictive abilities and satisfactory discriminatory power and can be used to predict the genetic risk of the first episode of VTE in the Chinese population. The simplified PRS-10 model is more efficient in clinical practice.

Meta-analysis of the relationship between methylenetetrahydrofolate reductase C677T and A1298C polymorphism and venous thromboembolism in the Caucasian and Asian

Recent years, it is a highly debated topic that whether methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and A1298C polymorphism could increase susceptibility to venous thromboembolism (VTE) in the Asian and Caucasian. Therefore, we expect to settle that controversy evidentially. Basic methods: Electronic databases (Pubmed, embase, Cochrane library, scopus, OvidSP, Wiley Online library, Springer link, EBSCO, Elsevier Science Direct, Google scholar) without date limitation were searched. Crude odds ratio (OR) along with 95% confidence interval (95% CI) was calculated to assess the association quantitatively. Finally, a total of 37 eligible studies were included, containing 31 for MTHFR C677T polymorphism and 6 for MTHFR A1298C polymorphism. The pooled results suggested that MTHFR C677T mutation may increase susceptibility to VTE in reverse recessive model (CC+CT vs TT): OR = 0.68 (0.56, 0.83), reverse dominant model (CC vs CT +TT): OR = 0.82 (0.72, 0.94), heterozygote model (CT vs TT): OR = 0.65 (0.52, 0.81), homozygote model (CC vs TT): OR = 0.73 (0.60, 0.89) and allele model (C vs T): OR = 0.80 (0.71, 0.90). Subgroup analysis about Asian also support that results, but Caucasian group not. In addition, MTHFR A1298C polymorphism may be not related to VTE in all genetic model. The results of meta-analysis indicated that MTHFR C677T polymorphism might increase the risk of VTE, especially in Asian population.

Targeted gene expression study using TaqMan low density array to gain insights into venous thrombo-embolism (VTE) pathogenesis at high altitude

Venous thrombo-embolism (VTE) is multi-factorial disease involving several genetic and acquired risk factors responsible for its onset. It may occur spontaneously upon climbing at High Altitude (HA). Several studies demonstrated that hypoxic conditions prevailing at HA pose an independent risk factor for VTE; however, molecular mechanism remains unknown. Present study aims to identify genes associated with HA-induced VTE pathophysiology using real time TaqMan Low-Density Array (TLDA) of known candidate genes. Gene expression of total 93 genes were studied and analyzed in patients of VTE from HA (HA-VTE) and from sea level (SL-VTE) in comparison to respective controls. Both HA-VTE and SL-VTE patients showed up-regulation of 37 genes involved in blood coagulation cascade, clot formation, platelet formation, endothelial response, angiogenesis, cell adhesion and calcium channel activity. Seven genes including ACE, EREG, C8A, DLG2, USF1, F2 and PCDHA7 were up-regulated in both HA-controls and VTE patients (both HA-VTE and SL-VTE) indicating their role during VTE event and also upon HA exposure. Ten genes; CDH18, FGA, EDNBR, GATA2, MAPK9, BCAR1, FRK, F11, PCDHA1 and ST8SIA4 were uniquely up-regulated in HA-VTE. The differentially expressed genes from the present study could be determining factors for HA-VTE susceptibility and provide insights into VTE occurrence at HA.

Analysis of Risk Factors for Lower-limb Deep Venous Thrombosis in Old Patients after Knee Arthroplasty

Background:

Deep venous thrombosis (DVT) is a common complication of arthroplasty in old patients. We analyzed risk factors for lower-limb DVT after arthroplasty in patients aged over 70 years to determine controllable risk factors.

Methods:

This was a retrospective study of 1,025 patients aged >70 years treated with knee arthroplasty at our hospital between January 2009 and December 2013. Of 1,025 patients, 175 had postoperative lower-limb DVT. We compared medical history, body mass index (BMI), ambulatory blood pressure, preoperative and postoperative fasting blood glucose (FBG), preoperative blood total cholesterol, triglyceride, high- and low-density lipoprotein cholesterol, and preoperative homocysteine (Hcy) between thrombus and non-thrombus groups. B-mode ultrasonography was used to detect lower-limb DVT before the operation and 7 days after the operation in all patients. Logistic regression analysis was used to determine risk factors for DVT.

Results:

Incidence of diabetes (P = 0.014), BMI (P = 0.003), preoperative FBG (P = 0.004), postoperative FBG (P = 0.012), and preoperative Hcy (P < 0.001) were significantly higher in the thrombus group. A significantly greater proportion of patients in the non-thrombus group had early postoperative activity (P < 0.001) and used a foot pump (P < 0.001). Operative duration was significantly longer in the thrombus group (P = 0.012). Within the thrombus group, significantly more patients had bilateral than unilateral knee arthroplasty (P < 0.01). Multivariate logistic analysis revealed BMI, preoperative Hcy, postoperative FBG, long operative duration, bilateral knee arthroplasty, and time to the activity after the operation to be predictive factors of DVT. At 6-month follow-up of the thrombus group, 4.7% of patients had pulmonary embolism and 18.8% had recurrent DVT; there were no deaths.

Conclusions:

Obesity, inactivity after operation, elevated preoperative Hcy and postoperative FBG, long operative duration, and bilateral knee arthroplasty were risk factors for DVT in patients aged over 70 years.

Association of a methylene tetrahydrofolate reductase C677T polymorphism with several blood chemical levels in a Chinese population

BACKGROUND

The methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism is associated with hypertension in certain populations. This study investigated the relationship between the MTHFR polymorphism and hypertension and correlated blood lipid indexes, including homocysteine (HCY), lipoprotein (a) [Lp (a)], high-density lipoprotein (HDL), low-density lipoprotein (LDL), apolipoprotein A I (Apo AI), Apo B, glucose (GLU), total cholesterol (TC), and triglyceride (TG), in a Chinese population.

MATERIALS AND METHODS

A total of 174 patients with hypertension and 634 healthy control individuals from Jiangxi Province were recruited between June 2012 and September 2012 for genotyping of the MTHFR C677T polymorphism using polymerase chain reaction-restriction fragment length polymorphism. Biochemical parameters were also assessed in these subjects and statistically compared to the MTHFR C677T polymorphism and the risk for hypertension.

RESULTS

HCY and Lp (a) levels were significantly higher in subjects with a MTHFR 677TT genotype than in those with a CC/CT genotype, independent of hypertension. The frequency of the TT genotype and the T allele in hypertension patients was significantly higher than in the healthy controls. Furthermore, in the male hypertension patient group, the average levels of HCY, HDL, Apo AI, and TC were significantly different from those in female hypertension patients (pHCY=0.001, pHDL=0.004, pApo AI<0.001, pTC=0.012). In the male control group, the average levels of HCY, HDL, Apo AI, GLU, and TC were significantly different from those of female controls (pHCY<0.001, pHDL<0.001, pApo AI<0.001, pGLU=0.001, and pTC=0.004).

CONCLUSION

Our data demonstrate that the MTHFR C677T polymorphism is positively correlated with an increased risk of hypertension through an increase in HCY levels. The blood lipid correlative index was different between male and female hypertension patients and controls.

Cyclic supplementation of 5-MTHF is effective for the correction of hyperhomocysteinemia

Folic acid supplementation is the mainstay treatment of hyperhomocysteinemia (HHcy). However, no recommendations are currently available in regard to the optimal replacement therapy. Therefore, this prospective study hypothesized that a cyclic schedule (1 month of therapy followed by 2 months of withdrawal) of 5-methyltetrahydrofolate (5-MTHF) would reduce plasma levels of fasting total homocysteine (tHcy) in patients with mild/moderate HHcy. Patients with a new diagnosis of mild/moderate HHcy were evaluated for the methylenetetrahydrofolate reductase genotype and the presence of major features of metabolic syndrome. All enrolled subjects received a cyclic 5-MTHF oral supplementation and were reevaluated after each treatment cycle for a total of 2 years. In the 246 enrolled subjects, a significant reduction of tHcy levels occurred after the first cycle of treatment (from 31.6 ± 13.6 to 14.4 ± 5.77 μmol/L, P < .001) and during the whole 2-year follow-up (from 31.6 ± 13.6 to 12.18 ± 3.03 μmol/L, P < .001). The values of tHcy returned to reference range in 117 subjects (51.3%) after the first cycle and in 198 (86.8%) during the follow-up. The risk of failure in tHcy level normalization was increased in patients with metabolic syndrome (hazard ratio [HR], 3.49; 95% confidence interval [CI], 1.46-8.36), higher baseline tHcy levels (HR, 1.045; 95% CI, 1.018-1.073), or methylenetetrahydrofolate reductase homozygous mutation (HR, 6.59; 95% CI, 2.64-16.4). This study clearly shows that a cyclic schedule (1 month of therapy followed by 2 months of withdrawal) of 5-MTHF supplementation is able to significantly reduce tHcy levels in patients with mild/moderate HHcy.

Genomewide analysis of rat periaqueductal gray-dorsal horn reveals time-, region- and frequency-specific mRNA expression changes in response to electroacupuncture stimulation

Electroacupuncture (EA) has been widely applied for illness prevention, treatment or rehabilitation in the clinic, especially for pain management. However, the molecular events that induce these changes remain largely uncharacterized. The periaqueductal gray (PAG) and the spinal dorsal horn (DH) have been verified as two critical regions in the response to EA stimulation in EA analgesia. In this study, a genetic screen was conducted to delineate the gene expression profile in the PAG-DH regions of rats to explore the molecular events of the analgesic effect induced by low-frequency (2-Hz) and high-frequency (100-Hz) EAs. Microarray analysis at two different time points after EA stimulation revealed time-, region- and frequency-specific gene expression changes. These expression differences suggested that modulation of neural-immune interaction in the central nervous system played an important role during EA analgesia. Furthermore, low-frequency EA could regulate gene expression to a greater degree than high-frequency EA. Altogether, the present study offers, for the first time, a characterized transcriptional response pattern in the PAG-DH regions followed by EA stimulation and, thus, provides a solid experimental framework for future in-depth analysis of the mechanisms underlying EA-induced effects.

Association between MTHFR C677T polymorphism and venous thromboembolism risk in the Chinese population: a meta-analysis of 24 case-controlled studies

The association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and venous thromboembolism (VTE) risk in the Chinese population has been widely reported, but results were inconsistent and underpowered. To elucidate the variable results, a meta-analysis and systematic review were performed from all case-controlled studies relating MTHFR C677T polymorphism by pooling data on them. We estimated the pooled odds ratio with its 95% confidence intervals to assess this possible association. Finally, a total of 24 studies with 2339 cases and 4048 controls were included in the current meta-analysis. Significant association was found with VTE risk for all genetic models. Subgroup analyses by type of VTE further identified the above-mentioned association in deep vein thrombosis/pulmonary embolism and splanchnic vein thrombosis. The findings from our meta-analysis support the associations of MTHFR C677T polymorphism with VTE risk in the Chinese population.

Thrombophilic Mutations as Risk Factor for Retinal Vein Occlusion

Background:

Retinal vein occlusion (RVO) is the second most common retinal vein disease and an important cause of blindness and visual morbidity. Many conditions are associated with RVO but the real role of the thrombophilic mutations is still unclear.

Aim:

To evaluate the potential role of thrombophilic mutations in RVO.

Methods:

We have evaluated 113 patients with RVO and compared with 104 volunteer controls. The controls were all healthy blood donors without previous venous thromboembolism episode or arterial thromboembolism episode. All patients were tested for 5 gene variants (here all named as mutations): factor V ( FV) Leiden (G1691A), factor II ( FII; G20210A), 5,1-methylenetetra-hydrofolate reductase ( MTHFR; C677T), plasminogen activator inhibitor 1 ( PAI-1; 4G/5G), and angiotensin-converting enzyme ( ACE; Del/Ins). Statistical analysis were performed by the 2-tailed chi-square test.

Results:

Statistical test showed that TT homozygous patients of the MTHFR C677T mutation ( P = .017) and heterozygous GA patients of the FII G20210A mutation ( P = .018) were significantly higher than that in controls. For FV Leiden, even if the values were higher in patients than in controls, P value was not statistically significant. Conversely, for the ACE (Ins/Del) and PAI-1 (4G/5G) mutations, no difference was observed among genotypes of patients with RVO and control participants.

Conclusions:

In our study, the FII G20210A and the MTHFR C677T mutations resulted significantly higher in patients than in controls; in contrast, thrombophilic mutation of FV, ACE, and PAI-1 genes was not statistically correlated with RVO. In spite of having found an association between some thrombophilic mutations and RVO, more studies with a major number of patients are necessary to determine the final role of these gene variants.

Clinical significance of determining plasma homocysteine: case-control study on arterial and venous thrombotic patients

Aim

To determine the differences in plasma homocysteine levels between three MTHFR 677 genotype subgroups in patients with thrombosis and in controls, as well as between patients with thrombosis and controls with the same MTHFR 677 genotype.

Methods

This case-control study was conducted in Clinical Center of Vojvodina, Novi Sad, from June to December 2011. We included 65 patients with either arterial or venous thrombosis (mean age, 40.97 ± 11.38 years) and 65 controls with no history or clinical evidence of any thrombotic event (mean age, 41.23 ± 11.12 years). Patients and controls were age- and sex-matched.

Results

In comparison with controls, thrombotic patients had significantly higher homocysteine levels (12.81 ± 4.94 µmol/L vs 9.82 ± 3.68 µmol/L; P < 0.001) and significantly higher incidence of hyperhomocysteinemia (55% vs 22%; P < 0.001; odds ratio [OR] = 4.521). There were no significant differences in homocysteine levels between homozygous carriers, heterozygous carriers, and non-carriers of the MTHFR 677 mutation in either thrombotic patients (12.97 ± 5.40 µmol/L vs 12.55 ± 5.71 µmol/L vs 13.27 ± 1.71 µmol/L; P = 0.100) or controls (10.07 ± 2.50 µmol/L vs 10.25 ± 4.84 µmol/L vs 9.20 ± 2.44 µmol/L; P = 0.651). However, in comparison with controls, homozygous carriers in thrombotic patient group did not have significantly higher levels of homocysteine (12.97 ± 5.40 µmol/L vs 10.07 ± 2.50 µmol/L; P = 0.072), but heterozygous carriers (12.55 ± 5.71 µmol/L vs 10.25 ± 4.84 µmol/L; P = 0.020) and non-carriers (13.27 ± 1.71 µmol/L vs 9.20 ± 2.44 µmol/L; P < 0.001) did. There was no significant difference in homocysteine levels between patients with arterial and venous thrombosis (12.76 ± 3.60 µmol/L vs 12.86 ± 5.51 µmol/L; P = 0.990) and between patients with one thrombotic event and those with recurrent thrombotic events (12.14 ± 3.20 µmol/L vs 15.25 ± 8.51 µmol/L; P = 0.254).

Conclusion

Plasma homocysteine levels have a greater clinical significance in the prevention of thrombosis and managing its complications than MTHFR 677 genotyping.

Sticky platelets syndrome in a young patient with massive pulmonary embolism

Patient:

Female, 51

Final Diagnosis:

Sticky platelets syndrome

Symptoms:

Pulmonary embolism

Medication:

—

Clinical Procedure:

Thrombolysis

Specialty:

Hematology

Objective:

Disease of unknown ethiology

Background:

Sticky platelets syndrome (SPS) is an inherited thrombophilia characterized by platelet hyperaggregability, which can lead to the higher risk of thrombosis. The etiology of SPS remains unclear, but several gene polymorphisms have been recently studied and autosomal dominant heredity is suspected. Although SPS is traditionally connected with arterial thrombosis, several cases of SPS as a cause of venous thromboembolism have been described.

Case Report:

We report the case of a 51-year-old apparently healthy woman with massive pulmonary embolism, who required thrombolytic therapy. In this patient SPS was identified as the only condition leading to higher risk of developing thromboembolic disease.

Conclusions:

Although at present few physicians have practical experience with SPS, this syndrome may lead to serious health problems or even death. The presented case points to the benefit of SPS diagnostics in standard screening of inherited thrombophilia for effective prophylaxis and treatment in patients with venous thromboembolism.