Racial or ethnic differences in allele frequencies of single-nucleotide polymorphisms in the methylenetetrahydrofolate reductase gene and their influence on response to methotrexate in rheumatoid arthritis

Practical Implementation of Artificial Intelligence-Based Deep Learning and Cloud Computing on the Application of Traditional Medicine and Western Medicine in the Diagnosis and Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA), an autoimmune disease of unknown etiology, is a serious threat to the health of middle-aged and elderly people. Although western medicine, traditional medicine such as traditional Chinese medicine, Tibetan medicine and other ethnic medicine have shown certain advantages in the diagnosis and treatment of RA, there are still some practical shortcomings, such as delayed diagnosis, improper treatment scheme and unclear drug mechanism. At present, the applications of artificial intelligence (AI)-based deep learning and cloud computing has aroused wide attention in the medical and health field, especially in screening potential active ingredients, targets and action pathways of single drugs or prescriptions in traditional medicine and optimizing disease diagnosis and treatment models. Integrated information and analysis of RA patients based on AI and medical big data will unquestionably benefit more RA patients worldwide. In this review, we mainly elaborated the application status and prospect of AI-assisted deep learning and cloud computation-oriented western medicine and traditional medicine on the diagnosis and treatment of RA in different stages. It can be predicted that with the help of AI, more pharmacological mechanisms of effective ethnic drugs against RA will be elucidated and more accurate solutions will be provided for the treatment and diagnosis of RA in the future.

MTHFR Polymorphism Is Associated With Severe Methotrexate-Induced Toxicity in Osteosarcoma Treatment

Background

Previous studies have revealed the critical role of methylene tetrahydrofolate reductase (MTHFR) polymorphisms in response to high-dose methotrexate (MTX)-induced toxicity in osteosarcoma patients. However, the conclusions remain controversial. In this setting, we performed a meta-analysis to determine their association more precisely.

Method

Eligible studies were searched and screened in PubMed, Web of Science, Cochrane Library, Clinical-Trials.gov, Embase, and China National Knowledge Infrastructure (CNKI) following specific inclusion and exclusion criteria. The required information was retrieved and collected for subsequent meta-analysis. Association between MTHFR polymorphism and MTX toxicity was evaluated by odds ratios (ORs).

Results

Seven studies containing 585 patients were enrolled and analyzed in this meta-analysis. Overall, the MTX related grade 3-4 liver toxicity was significantly associated with MTHFR rs1801133 allele (T vs. C: OR=1.61, 95%CI=1.07-2.42, P=0.024), homozygote (TT vs. CC: OR=2.11, 95%CI=1.06-4.21, P=0.011), and dominant genetic model (TT/TC vs. CC: OR=3.15, 95%CI=1.30-7.60, P=0.035) in Asian population. Meanwhile, close associations between MTX mediated grade 3-4 mucositis and MTHFR rs1801133 polymorphism were identified in allele contrast (T vs. C: OR=2.28, 95%CI=1.49-3.50, P<0.001), homozygote comparison (TT vs. CC: OR=4.07, 95%CI=1.76-9.38, P=0.001), heterozygote comparison (TC vs. CC: OR=2.55, 95%CI=1.20-5.42, P=0.015), recessive genetic model (TT vs. TC/CC: OR=2.09, 95%CI=1.19-3.67, P=0.010), and dominant genetic model (TT/TC vs. CC: OR=2.97, 95%CI=1.48-5.96, P=0.002). Additionally, kidney toxicity was corelated with the heterozygote comparison (TC vs. CC: OR=2.63, 95%CI=1.31-5.29, P=0.007) of rs1801133 polymorphism.

Conclusion

The MTHFR rs1801133 polymorphism was significantly associated with severer liver toxicity induced by high-dose MTX treatment in the Asian population. In the meantime, patients with MTHFR rs1801133 polymorphism were predisposed to MTX- related mucositis.

Impact of Posttranslational Modification in Pathogenesis of Rheumatoid Arthritis: Focusing on Citrullination, Carbamylation, and Acetylation

Rheumatoid arthritis (RA) is caused by prolonged periodic interactions between genetic, environmental, and immunologic factors. Posttranslational modifications (PTMs) such as citrullination, carbamylation, and acetylation are correlated with the pathogenesis of RA. PTM and cell death mechanisms such as apoptosis, autophagy, NETosis, leukotoxic hypercitrullination (LTH), and necrosis are related to each other and induce autoantigenicity. Certain microbial infections, such as those caused by Porphyromonasgingivalis, Aggregatibacter actinomycetemcomitans, and Prevotella copri, can induce autoantigens in RA. Anti-modified protein antibodies (AMPA) containing anti-citrullinated protein/peptide antibodies (ACPAs), anti-carbamylated protein (anti-CarP) antibodies, and anti-acetylated protein antibodies (AAPAs) play a role in pathogenesis as well as in prediction, diagnosis, and prognosis. Interestingly, smoking is correlated with both PTMs and AMPAs in the development of RA. However, there is lack of evidence that smoking induces the generation of AMPAs.

An Ethnic Variation in the Acceptance of Biological Disease-Modifying Therapies: A University Hospital Experience

Ethnic variations in the outcomes of rheumatological diseases are well documented. While physiological differences may account for these disparities, attitude to treatment is also likely to be a significant modifiable contributor. We sought to determine if an ethnic variation exists in the uptake of biological disease-modifying anti-rheumatic drugs (DMARD) among a multi-ethnic cohort when offered in-person through a healthcare system free at the point of access. We conducted a retrospective cross-sectional study of patients seen in a biologic therapy counselling clinic between December 2016 and April 2017. Clinic letters from consultations were reviewed, and data including ethnicity, language spoken, and decision to accept or reject the therapy were extracted. We chose to measure uptake over adherence, as we believe it is an earlier, more direct marker of attitudes to joint saving medications. Ninety-one cases were included in the analysis. Over 13.2% (12/91) of the cohort declined a biologic treatment when it was offered as the standard of care for joint disease. Non-Caucasian patients accepted treatment less often than Caucasian (White British) patients (OR 0.265, CI 0.73-0.959, p = 0.043), as did those who did not speak English as a first language (OR 0.094, CI 0.18-0.497, p = 0.005). Age, sex, and diagnosis were well matched between those who accepted and declined therapy. We demonstrate a disparity in the uptake of biologic therapies between the White British population and patients from other ethnicities. The reasons for this are likely multifactorial and could be related to socio-economic factors, language barriers, and cultural differences. Addressing this discrepancy is a crucial first step to tackling preventable disparities in the outcomes of rheumatological disease between different ethnicities.

Drug survival and predictor factors for discontinuation of methotrexate in psoriasis: a real-life multicenter study

BACKGROUND

Drug survival is useful to evaluate long-term drug performance in daily practice. The aim of this study was to evaluate drug survival for methotrexate (MTX) monotherapy in patients with plaque-type psoriasis.

METHODS

We reviewed 3,512 follow-up charts of patients with psoriasis at five tertiary referral centers between January 2012 and January 2020. We analyzed baseline data and treatment outcomes of patients under MTX monotherapy. Drug survival was analyzed using Kaplan-Meier and Cox regression analyses.

RESULTS

Patients with psoriasis who were treated with MTX monotherapy were enrolled (N = 649). The median duration of drug survival was 15 months (95% CI: 13.2-16.8). The overall drug survival rate was 54.7%, 17.4%, and 8% after 1, 3, and 5 years, respectively. The main reasons for discontinuation were adverse effects (n = 209, 32.2%) and inefficacy (n = 105, 15.6%). Based on multivariate Cox regression analysis, the presence of nausea/vomiting (HR: 2.01, 95% CI: 1.49-2.71; P < 0.001) was observed as a statistically significant risk factor for drug discontinuation. Age over 50 years (HR: 0.68, 95% CI: 0.48-0.97; P = 0.03) and using MTX dose ≥15 mg/weekly were positive predictors for drug survival (HR: 0.72, 95% CI: 0.54-0.95; P = 0.02).

CONCLUSIONS

The average drug survival of MTX was 15 months. MTX is still the first-line treatment of moderate-to-severe plaque psoriasis, as highlighted in guidelines. To prevent premature discontinuation, physicians need to look at the response time of at least 16-24 weeks, especially when a stepwise dose increment is used. The presence of nausea/vomiting seemed to be associated with an approximately twofold risk of discontinuation.

Investigation of association between genetic polymorphisms of MMP2, MMP8, MMP9 and TIMP2 and development of varicose veins in the Slovak Population - pilot study

Matrix metalloproteinases (MMPs) are a family of zinc-dependent metalloendopeptidases that degrades extracellular matrix (ECM) components. MMPs are associated with venous wall remodelling, proliferation, migration, phenotypic and functional transformation of vascular smooth muscle cells and ECM organization under the physiological and pathophysiological conditions. We investigated possible association of genetic promoter polymorphisms of MMP2 (rs243866), MMP8 (rs11225395), MMP9 (rs3918242) and TIMP2 (rs8179090) to varicose veins development in the Slovak population. Genomic DNA from 276 Slovak individuals (138 cases, 138 controls) was genotyped for selected SNPs (rs243866, rs11225395, rs3918242 and rs8179090) using the PCR-RFLP analysis. The data were analysed by chi-squared (chi2) test, logistic regression, and Mann-Whitney test. The risk of varicose veins development was evaluated in dominant, codominant and recessive genetic models. The statistical evaluation of selected polymorphisms in patients in all three genetic models has not shown a significant risk of varicose veins development. Our study has not shown the association between selected polymorphisms and increased risk of varicose veins development in Slovak population. More evidence with broaden sample size is needed.

MTHFR gene polymorphisms and susceptibility to rheumatoid arthritis: a meta-analysis based on 16 studies

Rheumatoid arthritis (RA) is the most common autoimmune rheumatic disease, in which an epigenetic implication in the disease etiopathogenesis has been noted. Here in this meta-analysis, we attempted to investigate the pooled association of methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphisms and susceptibility to RA risk. A systematic search was performed in the main databases, including MEDLINE and Scopus to search for studies assessing the association between MTHFR gene C677T and A1298C polymorphisms and the risk of RA prior to December 2019. In this meta-analysis, 15 studies with 2165 patients and 1751 healthy controls for C677T SNP and 14 studies containing 2021 patients and 1760 healthy controls for A1298C SNP were included. A significant positive association between C677T SNP and RA risk was recognized in the dominant, recessive, and allelic model, but not TT and CT genotypes. The results indicated that the risk of RA in African population was increased under all genotype models while these results were repeated in Asian population just for recessive model, allelic model, and TT genotype. Moreover, the analysis of A1298C SNP demonstrated a significant association in overall population according to only the recessive model and CC genotype. Subgroup analysis according to the genotyping method indicated that RFLP-PCR method could impress the results of association between MTHFR gene A1298C and C677T SNPs and RA risk. The outcome of this meta-analysis indicated that MTHFR gene C677T SNP was much possibly be associated with RA risk.

CHIMGEN: a Chinese imaging genetics cohort to enhance cross-ethnic and cross-geographic brain research

The Chinese Imaging Genetics (CHIMGEN) study establishes the largest Chinese neuroimaging genetics cohort and aims to identify genetic and environmental factors and their interactions that are associated with neuroimaging and behavioral phenotypes. This study prospectively collected genomic, neuroimaging, environmental, and behavioral data from more than 7000 healthy Chinese Han participants aged 18-30 years. As a pioneer of large-sample neuroimaging genetics cohorts of non-Caucasian populations, this cohort can provide new insights into ethnic differences in genetic-neuroimaging associations by being compared with Caucasian cohorts. In addition to micro-environmental measurements, this study also collects hundreds of quantitative macro-environmental measurements from remote sensing and national survey databases based on the locations of each participant from birth to present, which will facilitate discoveries of new environmental factors associated with neuroimaging phenotypes. With lifespan environmental measurements, this study can also provide insights on the macro-environmental exposures that affect the human brain as well as their timing and mechanisms of action.

Effects of Language, Insurance, and Race/Ethnicity on Measurement Properties of the PROMIS Physical Function Short Form 10a in Rheumatoid Arthritis

OBJECTIVE

Most studies that have evaluated patient-reported outcomes, such as those utilizing the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Short Form 10a (PF10a) in rheumatoid arthritis (RA), have been performed in white and English-speaking populations. The aim of our study was to assess the measurement properties of the PF10a in a racially/ethnically diverse population with RA and to determine the effect of non-English language proficiency, insurance status, and race/ethnicity on the validity and responsiveness of the PF10a.

METHODS

Data were abstracted from electronic health records for all RA patients seen in a university-based rheumatology clinic between 2013 and 2017. We evaluated the use of the PF10a, floor and ceiling effects, and construct validity across categories of language preference, insurance, and race/ethnicity. We used standardized response means and linear mixed-effects models to evaluate the responsiveness of the PF10a to longitudinal changes in the Clinical Disease Activity Index (CDAI) across population subgroups.

RESULTS

We included 595 patients in a cross-sectional analysis of validity and 341 patients in longitudinal responsiveness analyses of the PF10a. The PF10a had acceptable floor and ceiling effects and was successfully implemented. We observed good construct validity and responsiveness to changes in CDAI among white subjects, English speakers, and privately insured patients. However, constructs evaluated by the PF10a were less correlated with clinical measures among Chinese speakers and Hispanic subjects, and less sensitive to clinical improvements among Medicaid patients and Spanish speakers.

CONCLUSION

While the PF10a has good measurement properties and is both practical and acceptable for implementation in routine clinical practice, we also found important differences across racial/ethnic groups and those with limited English proficiency that warrant further investigation.

Genetic and clinical markers for predicting treatment responsiveness in rheumatoid arthritis

Although many drugs and therapeutic strategies have been developed for rheumatoid arthritis (RA) treatment, numerous patients with RA fail to respond to currently available agents. In this review, we provide an overview of the complexity of this autoimmune disease by showing the rapidly increasing number of genes associated with RA.We then systematically review various factors that have a predictive value (predictors) for the response to different drugs in RA treatment, especially recent advances. These predictors include but are certainly not limited to genetic variations, clinical factors, and demographic factors. However, no clinical application is currently available. This review also describes the challenges in treating patients with RA and the need for personalized medicine. At the end of this review, we discuss possible strategies to enhance the prediction of drug responsiveness in patients with RA.

Genetic polymorphisms of pharmacogenomic VIP variants in the Lisu population of southwestern China: A cohort study

Pharmacogenomic studies of different ethnic or racial groups have been used to develop personalized therapies specific to subjects. This study aimed to identify the distribution differences of very important pharmacogenetic (VIP) variants between the Lisu population from southwestern China and other ethnic groups.Eighty VIP variants in 37 genes were selected from the pharmacogenomic knowledge base (PharmGKB), and compared with genotype data of the Lisu population then compared with other 11 populations from the HapMap dataset and previously published data including Miao, Li, Deng, Sherpa, Lhoba, Tibetan, Kirghiz, Tajik, Mongol, Shaanxi Han ethnic, and Uygur populations.VDR rs1540339, MTHFR rs1801131, P2RY1 rs701265, and PTGS2 rs689466 were significantly different between Lisu and 11 HapMap populations. ANKK1 rs1800497 was the least statistical significant locus among selected single nucleotide polymorphisms. In addition, genetic background of Lisu was strongly closest to Shaanxi Han ethnic cohort, and followed by Chinese in metropolitan Denver population based on population structure and F-statistics analyses.Our results showed significant interethnic differences between Lisu and other populations, which will give useful information for prospective studies and better individualized treatments.

Psoriasis in Skin of Color: Insights into the Epidemiology, Clinical Presentation, Genetics, Quality-of-Life Impact, and Treatment of Psoriasis in Non-White Racial/Ethnic Groups

Psoriasis is a chronic inflammatory skin condition affecting diverse racial/ethnic groups throughout the world. Large population-based studies suggest that psoriasis occurs most often in individuals of European ancestry, followed by black and Hispanic individuals, although the true prevalence of psoriasis in non-white individuals is likely underestimated. Despite similarities in psoriasis between ethnic groups, there are notable differences in the presentation, quality-of-life impact, and treatment of psoriasis with important implications for the management of non-white individuals. Overall, heterogeneity in psoriasis susceptibility alleles, in combination with cultural and socioeconomic factors, may explain these differences. In this article, we review the epidemiology, clinical presentation, genetic polymorphisms, quality-of-life impact, and treatment nuances of psoriasis in patients with skin of color.

SNPs affecting the clinical outcomes of regularly used immunosuppressants

Recent studies have suggested that genomic diversity may play a key role in different clinical outcomes, and the importance of SNPs is becoming increasingly clear. In this article, we summarize the bioactivity of SNPs that may affect the sensitivity to or possibility of drug reactions that occur among the signaling pathways of regularly used immunosuppressants, such as glucocorticoids, azathioprine, tacrolimus, mycophenolate mofetil, cyclophosphamide and methotrexate. The development of bioinformatics, including machine learning models, has enabled prediction of the proper immunosuppressant dosage with minimal adverse drug reactions for patients after organ transplantation or for those with autoimmune diseases. This article provides a theoretical basis for the personalized use of immunosuppressants in the future.

Contribution of MTHFR gene variants in lupus related subclinical atherosclerosis

OBJECTIVE

Elevated concentrations of homocysteine have been previously identified as an independent risk factor for subclinical atherosclerosis in patients with systemic lupus erythematosus (SLE). Given that heightened homocysteine levels are known to be strongly influenced by genetic factors, in the current study we investigated the contribution of high homocysteine levels as well as of functional polymorphisms of the gene encoding for the enzyme 5, 10- methylenetetrahydrofolate reductase (MTHFR) to atherosclerotic disease characterizing SLE patients.

METHODS

Peripheral DNA samples from 150 SLE patients, 214 rheumatoid arthritis (RA) patients and 561 age/sex matched apparently healthy volunteers (HC) were genotyped by PCR-based assays for the detection of the MTHFR gene polymorphisms (c. 677C > T and c. 1298A > C). All SLE patients and 30 age sex matched RA patients underwent assessment for subclinical atherosclerosis [ultrasound measurement of intima-media thickness scores (IMT) and detection of carotid and/or femoral (C/F) plaque] and complete clinical and laboratory evaluation including serum homocysteine levels. Data were analyzed using univariate and multivariate models (SPSS 21.0).

RESULTS

Hyperhomocysteinemia was detected in 26.0% of SLE patients compared to 6.7% of age/sex matched RA controls (p = 0.02). Higher serum B12 levels and decreased frequency of the MTHFR 677TT variant in RA patients could potentially account for the observed differences between the groups. In SLE patients, both hyperhomocysteinemia and MTHFR 677TT genotype were identified as independent contributors for plaque formation, following adjustment for traditional cardiovascular risk factors and disease related features, including age, sex, BMI, cholesterol and triglyceride levels, presence of arterial hypertension, smoking (pack/years), disease duration and total steroid dose [OR 95% (CI): 5.8 (1.0-35.8) and 5.2 (1.1-24.0), respectively]. MTHFR 677TT genotype, but not hyperhomocysteinemia was also found to confer increased risk for arterial wall thickening, after the above confounders were taken into account [OR (95%) CI: 4.9 (1.2-20.6)].

CONCLUSIONS

Hyperhomocysteinemia and MTHFR 677TT genetic variant emerged as independent risk factors for subclinical atherosclerosis in SLE patients, implying genetic influences as potential contributors to the increased burden of atherosclerotic disease characterizing SLE.

Association of MTHFR C677T and A1298C gene polymorphisms with methotrexate efficiency and toxicity in Algerian rheumatoid arthritis patients

Methotrexate (MTX) is the most used drug in rheumatoid arthritis (RA) treatment. However, it shows variability in clinical response, which is explained by an association with genetic polymorphisms. This study aimed to elucidate the role of the two gene polymorphism C677T and A1298C of the methylenetetrahydrofolate reductase (MTHFR) in response to MTX in Algerian RA patients. Study included 54 early RA patient treated with MTX for one year. MTX efficiency and toxicity were evaluated at 6 and 12 months respectively and the two gene polymorphisms were genotyped. No association was found between A1298C polymorphism and MTX toxicity. However, T allele of the C677T polymorphism was associated with the occurrence of MTX adverse effects (p = 0,019, OR: 3,63, 95% CI [1,12 - 12,80]). No association was found between C677T polymorphism and MTX efficiency, while A allele of the A1298C polymorphism was associated with good and moderate response (p = 0,02, OR = 3,28, 95% CI: [1,11– 9,42]). The study of RA biological markers kinetics showed that MTX did not affect antibodies rate unlike inflammatory markers. Our study suggests that MTHFR C677T and A1298C genotyping are associated to MTX toxicity and efficiency, respectively, in RA patients. This offers new perspectives in the personalization of RA treatment in Algeria.

MTRR A66G, RFC1 G80A, and MTHFR C677T and A1298C Polymorphisms and Disease Activity in Mexicans with Rheumatoid Arthritis Treated with Methotrexate

Aim: To investigate the relationships of polymorphisms in genes whose protein products are related in the metabolic pathway of folic acid, particularly MTRR A66G, RFC1 G80A, and MTHFR C677T and A1298C, and disease activity in Mexican patients with rheumatoid arthritis (RA) treated with methotrexate (MTX).

Materials and Methods: Sixty-eight patients with RA were included in the study who were being treated with MTX, either with or without other drugs. In addition to general data, disease activity was measured by the disease activity score 28 (DAS28). Single nucleotide polymorphisms (SNPs) genotyping was performed by allelic discrimination using real-time polymerase chain reaction.

Results: Differences in genotype (homozygotic or heterozygotic for each allele), allele distributions, and phenotype were not statistically different between the RA group and control populations. We did not find any association between the studied polymorphisms and disease activity nor with the intragroup variables (e.g., clinical activity, body mass index, and single- or combined-drug treatment) or between genetic markers; we also did not find any association within the RA group or between the RA group and control populations.

Conclusion: Additional studies of more polymorphisms related to this or other metabolic pathways are required to determine the influence of genetics on disease activity in RA.

Analysis of population-specific pharmacogenomic variants using next-generation sequencing data

Functional rare variants in drug-related genes are believed to be highly differentiated between ethnic- or racial populations. However, knowledge of population differentiation (PD) of rare single-nucleotide variants (SNVs), remains widely lacking, with the highest fixation indices, (F_st values), from both rare and common variants annotated to specific genes, having only been marginally used to understand PD at the gene level. In this study, we suggest a new, gene-based PD method, PD of Rare and Common variants (PDRC), for analyzing rare variants, as inspired by Generalized Cochran-Mantel-Haenszel (GCMH) statistics, to identify highly population-differentiated drug response-related genes (“pharmacogenes”). Through simulation studies, we reveal that PDRC adequately summarizes rare and common variants, due to PD, over a specific gene. We also applied the proposed method to a real whole-exome sequencing dataset, consisting of 10,000 datasets, from the Type 2 Diabetes Genetic Exploration by Next-generation sequencing in multi-Ethnic Samples (T2D-GENES) initiative, and 3,000 datasets from the Genetics of Type 2 diabetes (Go-T2D) repository. Among the 48 genes annotated with Very Important Pharmacogenetic summaries (VIPgenes), in the PharmGKB database, our PD method successfully identified candidate genes with high PD, including ACE, CYP2B6, DPYD, F5, MTHFR, and SCN5A.

Associations between C677T and A1298C polymorphisms of MTHFR and susceptibility to rheumatoid arthritis: a systematic review and meta-analysis

Methylenetetrahydrofolatereductase (MTHFR) is an important enzyme involved in folate metabolism and DNA synthesis. Although a number of studies have examined the association of the MTHFR C677T and A1298C polymorphisms with susceptibility to rheumatoid arthritis (RA), the conclusions are controversial. A comprehensive literature search using PubMed, Embase, the Cochrane Library, CNKI and Wanfang databases was conducted for relevant studies on the association between MTHFR polymorphisms and RA risk. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using fixed- and random-effect models. In total, 1854 cases and 1689 controls from 12 studies and 1525 cases and 1455 controls from 10 studies were included for the C677T and A1298C polymorphisms, respectively. Pooled results indicated that both C677T and A1298C polymorphisms were associated with RA susceptibility (C677T: TT vs. CC, OR = 1.31, 95% CI = 1.02-1.67, P = 0.032; TC vs. CC, OR = 1.32, 95% CI = 1.02-1.70, P = 0.032; TT + TC vs. CC, OR = 1.38, 95% CI = 1.07-1.78, P = 0.014; T vs. C, OR = 1.29, 95% CI = 1.06-1.57, P = 0.011; A1298C: CC vs. CA + AA: OR = 1.58, 95% CI = 1.20-2.06, P = 0.001). Further stratification based on ethnicity and geographic region indicated an association between the MTHFR C677T SNP and the risk of RA in Caucasian and patients in Africa. However, there is no evidence of significant association between A1298C polymorphism and RA risk in Caucasian or population in Africa. This meta-analysis indicates that MTHFR C677T and A1298C polymorphisms could be predictors of risk of RA and warrants validation in large and well-designed prospective studies.

Genetic polymorphisms of enzyme proteins and transporters related to methotrexate response and pharmacokinetics in a Japanese population

Background

Methotrexate (MTX) is currently the anchor drug widely used worldwide in the treatment of rheumatoid arthritis (RA). However, the therapeutic response to MTX has been shown to vary widely among individuals, genders and ethnic groups. The reason for this has been not clarified but it is considered to be partially due to several mechanisms in the cellular pathway of MTX including single-nucleotide polymorphisms (SNPs). The purpose of this study was to investigate the allelic frequencies in different ethnic and/or population groups in the 10 polymorphisms of enzyme proteins and transporters related to the MTX response and pharmacokinetics including MTHFR, TYMS, RFC1, FPGS, GGH, ABCB1, ABCC2 and ABCG2 in unrelated healthy Japanese adults and patients with RA.

Methods

Ten polymorphisms, methylenetetrahydrofolate reductase (MTHFR) 1298, thymidylate synthase (TYMS) 3'-UTR, reduced folate carrier 1 (RFC1) 80 and−43, folypolyglutamyl synthase (FPGS) 1994, γ-glutamyl hydrolase (GGH) 452 and−401, the ABC transporters (ABCB1 3435, ABCC2 IVS23 + 56, ABCG2 914) of enzyme proteins and transporters related to MTX response and pharmacokinetics in 299 unrelated healthy Japanese adults and 159 Japanese patients with RA were investigated to clarify their contributions to individual variations in response and safety to MTX and establish personalized MTX therapy. SNPs were evaluated using real-time polymerase chain reaction (PCR).

Results

Comparison of allelic frequencies in our study with other ethnic/population groups of healthy adults and RA patients showed significant differences in 10 polymorphisms among healthy adults and 7 among RA patients. Allelic frequencies of MTHFR 1298 C, FPGS 1994A and ABCB1 3435 T were lower in Japanese than in Caucasian populations and those of ABCC2 IVS23 + 56 C and ABCG2 914A were higher in Japanese than in Caucasian/European populations in both healthy adults and RA patients. Allelic frequencies of MTHFR 1298 C, GGH−401 T, ABCB1 3435 T, and ABCG2 914A were higher in healthy Japanese adults than in an African population, and those of RFC1 80A, RFC1−43C and ABCC2 IVS23 + 56 C in healthy Japanese adults were lower than in Africans. However, no significant differences were seen in the distribution of allelic frequencies between healthy Japanese adults and RA patients.

Conclusion

The variations in allelic frequencies in different ethnic and/or population groups in healthy adults and RA patients may contribute to individual variations in MTX response and toxicity.

Presence of the methylenetetrahydrofolate reductase gene polymorphism MTHFR C677T in molar tissue but not maternal blood predicts failure of methotrexate treatment for low-risk gestational trophoblastic neoplasia

Gestational trophoblastic neoplasia (GTN) is a rare tumor, and its genomic constitution is different from the maternal genome because of its gestational origin. Methotrexate (MTX) is a standard chemotherapeutic agent for low-risk GTN. An association between polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene and MTX treatment outcome has been reported in various diseases. Thus, we examined the association between clinical outcome and MTHFR polymorphisms in both tumor and blood DNA of low-risk GTN patients. MTHFR C677T (rs1801133) and A1298C (rs1801131) were genotyped using high-resolution melting assays in 62 Japanese low-risk GTN patients and in 52 antecedent molar tissues. We compared the genotypes of MTHFR polymorphisms with the clinical outcome of 5-day MTX treatment. Twenty-five patients entered remission and 37 patients developed drug resistance or adverse effects that necessitated a drug change. The MTHFR 677T allele in molar tissue was significantly related to the need for drug change (P=0.006; odds ratio [OR], 3.13; 95% confidence interval [CI], 1.31-7.49), in contrast to MTHFR 1298C (P=0.18; OR, 0.63; 95% CI, 0.32-1.25). The MTHFR 677T and 1298C alleles obtained from patients' blood DNA were not related to MTX treatment outcome (P=0.49; OR 1.31; 95% CI, 0.61-2.91 and P=0.10; OR 0.52; 95% CI, 0.22-1.15, respectively). These data demonstrate for the first time that the genotype of MTHFR 677TT in molar tissue is associated with ineffective MTX treatment in Japanese low-risk GTN patients.

Methylene tetrahydrofolate reductase, transforming growth factor-β1 and lymphotoxin-α genes polymorphisms and susceptibility to rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition.

OBJECTIVES

The aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677 T and A1298 C), transforming growth factor-β1 (TGF-β1 T869 C) and lymphotoxin-α (LT-α A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factor-alpha (TNF-α), B-Cell Activating Factor (BAFF), and osteopontin.

METHODS

A total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677 T and A1298 C, TGF-β1 T869 C and LT-α A252G polymorphisms using a methodology based on PCR-RFLP. Also serum levels of TNF-α, osteopontin and BAFF were measured by ELISA kits.

RESULTS

The CT genotype and T allele of MTHFR C677 T and GG genotype and G allele of LT-α A252G are associated with the risk of RA and with higher levels of the pro-inflammatory cytokine, TNF-α in patients with rheumatoid arthritis.

CONCLUSION

Our findings suggest that there is association between MTHFR C677 T and LT-α A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population.

Genetic Case-Control Study for Eight Polymorphisms Associated with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease which has a significant socio-economic impact. The aim of the current study was to investigate eight candidate RA susceptibility loci to identify the associated variants in Egyptian population. Eight single nucleotide polymorphisms (SNPs) (MTHFR—C677T and A1298C, TGFβ1 T869C, TNFB A252G, and VDR—ApaI, BsmI, FokI, and TaqI) were tested by genotyping patients with RA (n = 105) and unrelated controls (n = 80). Associations were tested using multiplicative, dominant, recessive, and co-dominant models. Also, the linkage disequilibrium (LD) between the VDR SNPs was measured to detect any indirect association. By comparing RA patients with controls (TNFB, BsmI, and TaqI), SNPs were associated with RA using all models. MTHFR C677T was associated with RA using all models except the recessive model. TGFβ1 and MTHFR A1298C were associated with RA using the dominant and the co-dominant models. The recessive model represented the association for ApaI variant. There were no significant differences for FokI and the presence of RA disease by the used models examination. For LD results, There was a high D′ value between BsmI and FokI (D′ = 0.91), but the r² value between them was poor. All the studied SNPs may contribute to the susceptibility of RA disease in Egyptian population except for FokI SNP.

Genetic polymorphisms affect efficacy and adverse drug reactions of DMARDs in rheumatoid arthritis

Disease-modifying antirheumatic drugs (DMARDs) and biological agents are critical in preventing the severe complications of rheumatoid arthritis (RA). However, the outcome of treatment with these drugs in RA patients is quite variable and unpredictable. Drug-metabolizing enzymes (dihydrofolate reductase, cytochrome P450 enzymes, N-acetyltransferases, etc.), drug transporters (ATP-binding cassette transporters), and drug targets (tumor necrosis factor-α receptors) are coded for by variant alleles. These gene polymorphisms may influence the pharmacokinetics, pharmacodynamics, and side effects of medicines. The cause for differences in efficacy and adverse drug reactions may be genetic variation in drug metabolism among individuals. Polymorphisms in drug transporter genes may change the distribution and excretion of medicines, and the sensitivity of the targets to drugs is strongly influenced by genetic variations. In this article, we review the genetic polymorphisms that affect the efficacy of DMARDs or the occurrence of adverse drug reactions associated with DMARDs in RA.

Review article: The pharmacokinetics and pharmacodynamics of drugs used in inflammatory bowel disease treatment

BACKGROUND

The following review is a compilation of the recent advances and knowledge on the behaviour of the most frequently used compounds to treat inflammatory bowel disease in an organism.

RESULTS

It considers clinical aspects of each entity and the pharmacokinetic/pharmacodynamic relationship supported by the use of plasma monitoring, tissue concentrations, and certain aspects derived from pharmacogenetics.

Outcomes related to methotrexate dose and route of administration in patients with rheumatoid arthritis: a systematic literature review

OBJECTIVES

Methotrexate (MTX) is considered the 'anchor drug' in the therapy of rheumatoid arthritis (RA), yet many physicians do not optimise MTX regimens in spite of high RA disease activity. The recent development of an auto-injector for the subcutaneous (subQ) administration of MTX has prompted re-evaluation of MTX utilisation. The purpose of this systematic literature review is to determine the optimal dose, drug level, and route of administration for MTX in the context of relevant pharmacokinetics and pharmacogenomics.

METHODS

A systematic literature review was performed in Medline searching specifically for randomised controlled trials, systematic reviews, case control and cohort studies evaluating outcomes related to MTX dose and route of administration. Articles fulfilling these inclusion criteria were reviewed. Data on MTX dose, route of administration, clinical response, drug levels and adverse events were evaluated.

RESULTS

Our search identified 420 articles of which 6 were eligible for inclusion using the above criteria. These included 2 systematic reviews, 2 randomised open label trials, one longitudinal study and one retrospective cohort study.

CONCLUSIONS

Efficacy and toxicity for MTX appear related to absorbed dose of MTX, not to route of administration. While bioavailability is greater for parenteral MTX, there is no evidence yet that splitting the oral dose of MTX is less advantageous, less safe or less tolerable than administering parenteral MTX. However, there appear to be modest benefits in beginning with higher doses of MTX, and switching to parenteral MTX when the clinical response to an oral dose is inadequate.

Genotype and allele frequencies of drug-metabolizing enzymes and drug transporter genes affecting immunosuppressants in the Spanish white population

Interpatient variability in drug response can be widely explained by genetically determined differences in metabolizing enzymes, drug transporters, and drug targets, leading to different pharmacokinetic and/or pharmacodynamic behaviors of drugs. Genetic variations affect or do not affect drug responses depending on their influence on protein activity and the relevance of such proteins in the pathway of the drug. Also, the frequency of such genetic variations differs among populations, so the clinical relevance of a specific variation is not the same in all of them. In this study, a panel of 33 single nucleotide polymorphisms in 14 different genes (ABCB1, ABCC2, ABCG2, CYP2B6, CYP2C19, CYP2C9, CYP3A4, CYP3A5, MTHFR, NOD2/CARD15, SLCO1A2, SLCO1B1, TPMT, and UGT1A9), encoding for the most relevant metabolizing enzymes and drug transporters relating to immunosuppressant agents, was analyzed to determine the genotype profile and allele frequencies in comparison with HapMap data. A total of 570 Spanish white recipients and donors of solid organ transplants were included. In 24 single nucleotide polymorphisms, statistically significant differences in allele frequency were observed. The largest differences (>100%) occurred in ABCB1 rs2229109, ABCG2 rs2231137, CYP3A5 rs776746, NOD2/CARD15 rs2066844, TPMT rs1800462, and UGT1A9 rs72551330. In conclusion, differences were recorded between the Spanish and other white populations in terms of allele frequency and genotypic distribution. Such differences may have implications in relation to dose requirements and drug-induced toxicity. These data are important for further research to help explain interindividual pharmacokinetic and pharmacodynamic variability in response to drug therapy.

Identification of rheumatoid arthritis biomarkers based on single nucleotide polymorphisms and haplotype blocks: A systematic review and meta-analysis

Genetics of autoimmune diseases represent a growing domain with surpassing biomarker results with rapid progress. The exact cause of Rheumatoid Arthritis (RA) is unknown, but it is thought to have both a genetic and an environmental bases. Genetic biomarkers are capable of changing the supervision of RA by allowing not only the detection of susceptible individuals, but also early diagnosis, evaluation of disease severity, selection of therapy, and monitoring of response to therapy. This review is concerned with not only the genetic biomarkers of RA but also the methods of identifying them. Many of the identified genetic biomarkers of RA were identified in populations of European and Asian ancestries. The study of additional human populations may yield novel results. Most of the researchers in the field of identifying RA biomarkers use single nucleotide polymorphism (SNP) approaches to express the significance of their results. Although, haplotype block methods are expected to play a complementary role in the future of that field.

A lower degree of PBMC L1 methylation in women with lower folate status may explain the MTHFR C677T polymorphism associated higher risk of CIN in the US post folic acid fortification era

BACKGROUND

Studies in populations unexposed to folic acid (FA) fortification have demonstrated that MTHFR C677T polymorphism is associated with increased risk of higher grades of cervical intraepithelial neoplasia (CIN 2+). However, it is unknown whether exposure to higher folate as a result of the FA fortification program has altered the association between MTHFR C677T and risk of CIN, or the mechanisms involved with such alterations. The current study investigated the following in a FA fortified population: 1) The association between MTHFR C677T polymorphism and risk of CIN 2+; 2) The modifying effects of plasma folate concentrations on this association; and 3) The modifying effects of plasma folate on the association between the polymorphism and degree of methylation of long interspersed nucleotide elements (L1s), in peripheral blood mononuclear cell (PBMC) DNA, a documented biomarker of CIN risk.

METHODS

The study included 457 US women diagnosed with either CIN 2+ (cases) or ≤ CIN 1 (non-cases). Unconditional logistic regression models were used to test the associations after adjusting for relevant risk factors for CIN.

RESULTS

The 677CT/TT MTHFR genotypes were not associated with the risk of CIN 2+. Women with CT/TT genotype with lower folate, however, were more likely to be diagnosed with CIN 2+ compared to women with CT/TT genotype with higher folate (OR = 2.41, P = 0.030). Women with CT/TT genotype with lower folate were less likely to have a higher degree of PBMC L1 methylation compared to women with CT/TT genotype with higher folate (OR = 0.28, P = 0.017).

CONCLUSIONS

This study provides the first evidence that the MTHFR 677CT/TT genotype-associated lower degree of PBMC L1 methylation increases the risk of CIN 2+ in women in the US post-FA fortification era. Thus, even in the post-FA fortification era, not all women have adequate folate status to overcome MTHFR 677CT/TT genotype-associated lower degree of L1 methylation.

Tolerability and pharmacokinetics of disodium folinate following single intravenous doses in healthy Chinese subjects: an open-label, randomized, single-center study

The tolerability and pharmacokinetics of disodium folinate may vary with different races, and these variations might result in different outcomes. This study assessed the tolerability and pharmacokinetics of disodium folinate following single intravenous doses in healthy Chinese subjects, with gender factor also taken into account. Subjects were randomized to receive a single dose of disodium folinate at 20, 200, or 300 mg/m(2) administered intravenously over a time period of 10 min. Sequential blood samples were collected at regular intervals over 24 h after dosing and were analyzed using a validated high-performance liquid chromatography (HPLC) method. Pharmacokinetic parameters, including C max, AUC0-t, t 1/2, V d, and CL, were calculated using non-compartmental models. Tolerability was assessed by collecting adverse events (AEs) and monitoring vital signs, physical examinations, laboratory tests, and electrocardiograms. Following a single intravenous administration of disodium folinate 20, 200, and 300 mg/m(2), the mean (standard deviation) pharmacokinetic parameters were as follows: C max = 5.18 (0.58), 47.80 (10.10), and 69.93 (9.72) µg/mL; AUC0-t = 25.85 (3.36), 194.53 (30.18), and 355.26 (35.31) µg h/mL; AUC0-∞ = 30.24 (6.19), 215.43 (27.34), and 417.88 (54.81) µg h/mL; t 1/2 = 8.77 (2.57), 7.64 (1.81), and 9.08 (1.64) h; CL = 1.12 (0.18), 1.55(0.25), and 0.78 (0.09) L/h; V d = 13.75 (2.61), 17.38 (6.44), and 10.05 (1.49) L, respectively. The mean C max, AUC0-t, and AUC0-∞ increased in a dose-proportional manner. No significant differences in pharmacokinetic parameters were noted by gender. The most common AEs reported were mild redness at the injection site and neurological symptoms (headache, dizziness, and fatigue).

Methotrexate pharmacogenetics in rheumatoid arthritis: a status report

Methotrexate (MTX), an antifolate drug, is the first-line disease-modifying agent for the treatment of rheumatoid arthritis (RA) worldwide. MTX has excellent long-term efficacy, tolerability and safety. Early initiation of MTX in patients with RA controls joint destruction and slows progression of disease. However, the clinical response to MTX and frequency of adverse effects from the drug exhibit marked interpatient variability. Over the past decade, there has been a quest to identify genetic markers that reliably predict MTX efficacy and toxicity and help optimize MTX therapy in RA; that is, the field of MTX pharmacogenetics. This review will summarize key pharmacogenetic studies examining SNPs in the genes encoding enzymes in the MTX cellular pathway and their association with MTX response in RA. As evident from this review, MTX pharmacogenetics in RA remains a muddled field, mostly due to inconsistent results from several small underpowered studies.

Prevalence of MTHFR C677T single nucleotide polymorphism in genetically isolated populations in Jordan

Methylenetetrahydrofolate reductase (MTHFR) C677T single nucleotide polymorphism is a major inherited risk factor of venous thromboembolism. We sought to determine its prevalence in genetically isolated populations of Chechens and Circassians in Jordan. The MTHFR C677T mutation was analyzed from blood samples taken from 120 random unrelated Chechens and 72 Circassians. The prevalence of the MTHFR mutation in the Chechen population was 27.5% (allele frequency 15%); the prevalence among the Circassians was 50% (allele frequency 29.2%). The prevalence in the Chechen population is similar to that in Jordan and other world populations, but it is higher in the Circassian population. This study will contribute to understanding the interaction between genetic and environmental risk factors underlying thrombosis and will be useful in deciding which genetic variants should be tested in a clinical genetic testing service.

Genetic variants associated with methotrexate efficacy and toxicity in early rheumatoid arthritis: results from the treatment of early aggressive rheumatoid arthritis trial

Methotrexate (MTX) has emerged as first-line therapy for early moderate to severe rheumatoid arthritis (RA), but individual variation in treatment response remains unexplained. We tested the associations between 863 known pharmacogenetic variants and MTX response in 471 TEAR Trial participants with early RA. Efficacy and toxicity were modeled using multiple regression, adjusted for demographic and clinical covariates. Penalized regression models were used to test joint associations of markers and/or covariates with the outcomes. The strongest genetic associations with efficacy were in CHST11 (five markers with P <0.003), encoding carbohydrate (chondroitin 4) sulfotransferase 11. Top markers associated with MTX toxicity were in the cytochrome p450 genes CYP20A1 and CYP39A1, solute carrier genes SLC22A2 and SLC7A7, and the mitochondrial aldehyde dehydrogenase gene ALDH2. The selected markers explained a consistently higher proportion of variation in toxicity than efficacy. These findings could inform future development of personalized therapeutic approaches.

Pharmacogenetics of disease-modifying antirheumatic drugs in rheumatoid arthritis: towards personalized medicine

Rheumatoid arthritis is a disease showing considerable heterogeneity in all its aspects, including response to therapy. The efficacy of disease-modifying antirheumatic drugs (DMARDs), with or without biological activity, has been unambiguously established. DMARDs improve the symptoms associated with the disease, and, even more importantly, are capable of stagnating the joint damage associated with the disease. Nonetheless, a considerable proportion of patients fail to achieve an adequate response and/or experience toxicity. This variability in treatment response between individuals has given rise to an extensive search for prognostic markers in order to personalize and optimize therapy in rheumatoid arthritis patients. Pharmacogenetics, the study of genetic variation underlying differential responses to drugs, is a rapidly progressing field in rheumatology that might enable personalized therapy in rheumatic diseases. This review will summarize the pharmacogenetics of commonly used synthetic and biological DMARDs.

Old drugs, old problems: where do we stand in prediction of rheumatoid arthritis responsiveness to methotrexate and other synthetic DMARDs?

Methotrexate (MTX) is the central drug in the management of rheumatoid arthritis (RA) and other immune mediated inflammatory diseases. It is widely used either in monotherapy or in association with other synthetic and biologic disease modifying anti-rheumatic drugs (DMARDs). Although comprehensive clinical experience exists for MTX and synthetic DMARDs, to date it has not been possible to preview correctly whether or not a patient will respond to treatment with these drugs. Predicting response to MTX and other DMARDs would allow the selection of patients based on their likelihood of response, thus enabling individualized therapy and avoiding unnecessary adverse effects and elevated costs. However, studies analyzing this issue have struggled to obtain consistent, replicable results and no factor has yet been recognized to individually distinguish responders from nonresponders at treatment start. Variables possibly influencing drug effectiveness may be disease-, patient- or treatment-related, clinical or biological (genetic and nongenetic). In this review we summarize current evidence on predictors of response to MTX and other synthetic DMARDs, discuss possible causes for the heterogeneity observed and address its translation into daily clinical practice.

Chapter 7: Pharmacogenomics

There is great variation in drug-response phenotypes, and a “one size fits all” paradigm for drug delivery is flawed. Pharmacogenomics is the study of how human genetic information impacts drug response, and it aims to improve efficacy and reduced side effects. In this article, we provide an overview of pharmacogenetics, including pharmacokinetics (PK), pharmacodynamics (PD), gene and pathway interactions, and off-target effects. We describe methods for discovering genetic factors in drug response, including genome-wide association studies (GWAS), expression analysis, and other methods such as chemoinformatics and natural language processing (NLP). We cover the practical applications of pharmacogenomics both in the pharmaceutical industry and in a clinical setting. In drug discovery, pharmacogenomics can be used to aid lead identification, anticipate adverse events, and assist in drug repurposing efforts. Moreover, pharmacogenomic discoveries show promise as important elements of physician decision support. Finally, we consider the ethical, regulatory, and reimbursement challenges that remain for the clinical implementation of pharmacogenomics.

Chemotherapy-induced toxicity is highly heritable in Drosophila melanogaster

OBJECTIVES

Identification of the genes responsible for chemotherapy toxicity in Drosophila melanogaster may allow for the identification of human orthologs that similarly mediate toxicity in humans. To develop D. melanogaster as a model of dissecting chemotoxicity, we first need to develop standardized high-throughput toxicity assays and prove that the interindividual variation in toxicity as measured by such assays is highly heritable.

METHODS

We developed a method for the oral delivery of commonly used chemotherapy drugs to Drosophila. Post-treatment female fecundity displayed a dose-dependent response to varying levels of the chemotherapy drug delivered. We fixed the dose for each drug at a level that resulted in a 50% reduction in fecundity and used a paternal half-sibling heritability design to calculate the heritability attributable to chemotherapy toxicity assayed by a decrease in female fecundity. The chemotherapy agents tested were carboplatin, floxuridine, gemcitabine hydrochloride, methotrexate, mitomycin C, and topotecan hydrochloride.

RESULTS

We found that six currently widely prescribed chemotherapeutic agents lowered fecundity in D. melanogaster in both a dose-dependent and a highly heritable manner. The following heritability estimates were found: carboplatin, 0.72; floxuridine, 0.52; gemcitabine hydrochloride, 0.72; methotrexate, 0.99; mitomycin C, 0.64; and topotecan hydrochloride, 0.63.

CONCLUSION

The high heritability estimates observed in this study, irrespective of the particular class of drug examined, suggest that human toxicity may also have a sizable genetic component.

Effect of genetic polymorphisms in the folate pathway on methotrexate therapy in rheumatic diseases

Methotrexate (MTX) is the first-line treatment for rheumatoid arthritis and is frequently used in the management of other forms of inflammatory arthritis. It is currently challenging to predict which patients will achieve adequate disease control and which patients will develop adverse effects while taking MTX. As an analog of dihydrofolic acid, MTX enters cells through the reduced folate carrier-1 protein, and is polyglutamated. MTX polyglutamates inhibit key enzymes in the folate pathway to produce an anti-inflammatory effect. It has been suggested that genetic polymorphisms in the folate pathway may influence intracellular folate and MTX polyglutamates pools, and thus MTX response. However, studies to identify genetic predictors have yielded inconclusive results. Nonreplication across studies has been attributed to insufficient statistical power as well as pharmacological and clinical confounders. Prospective studies, standardizing the definitions of response and toxicity, and application of genome-wide approaches may advance the search for genetic predictors of MTX response.