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Zhang MY, Gao F, Zhao YW, Ni BW, Huang HH, Hou J. Inferior survival and frequent hepatic dysfunction in non-Hodgkin's lymphoma patients with HBV infection: a systematic review and meta-analysis. Hematology 2021; 27:70-79. [PMID: 34957924 DOI: 10.1080/16078454.2021.2011546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
OBJECTIVES No clear consensus has been reached about the clinical features in hepatitis B virus (HBV)-associated non-Hodgkin's lymphoma (NHL) patients. We performed a systematic review and meta-analysis to explore the clinical characteristics and prognosis of NHL patients with chronic HBV infection (HBsAg+). METHODS Seven electronic databases were searched for relevant studies up to 31 January 2021. Hazard ratio (HR) or odds ratio (OR) corresponding to 95% confidence interval (CI) were calculated to estimate the outcomes. The primary outcome was survival outcome, including overall survival (OS) and progression-free survival (PFS). Subgroup analysis was performed in diffuse large B-cell lymphoma (DLBCL) patients. RESULTS Twenty-three retrospective studies, comprising of 1202 HBsAg+ NHL patients and 4448 HBsAg- NHL patients, were included. Twenty-two studies were conducted on Chinese patients. Compared with HBsAg- NHL patients, significantly shorter OS (HR 1.68; 95% CI 1.48-1.91) and PFS (HR 1.80; 95% CI 1.20-2.71), lower rate of complete remission (OR 0.59, 95% CI 0.44-0.80) and higher frequency of hepatic dysfunction during chemotherapy (OR 3.46; 95% CI 2.61-4.57) were demonstrated in HBsAg+ NHL patients. Moreover, HBsAg+ patients were characterized by a younger age of disease onset, advanced disease stage, higher level of LDH and more frequent presence of B symptoms, and involvement of spleen and liver at diagnosis. Furthermore, subgroup analysis in DLBCL patients was also showed similar results. CONCLUSION Our study implicated that NHL patients, especially DLBCL, with chronic HBV infection displayed inferior prognosis, higher incidence of hepatic dysfunction during chemotherapy and distinct clinical features.
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Affiliation(s)
- Min-Yue Zhang
- Division of Hematology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Fei Gao
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, People's Republic of China
| | - Yan-Wei Zhao
- Division of Hospitalist, Shanghai Jiahui International Hospital, Shanghai, People's Republic of China
| | - Bei-Wen Ni
- Division of Hematology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Hong-Hui Huang
- Division of Hematology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Jian Hou
- Division of Hematology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
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You M, Zhou X, Yin W, Wan K, Zhang W, Li C, Li M, Zhu W, Zhu X, Sun Z. The Influence of MTHFR Polymorphism on Gray Matter Volume in Patients With Amnestic Mild Cognitive Impairment. Front Neurosci 2021; 15:778123. [PMID: 34916904 PMCID: PMC8670096 DOI: 10.3389/fnins.2021.778123] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 11/05/2021] [Indexed: 12/17/2022] Open
Abstract
The methylenetetrahydrofolate reductase (MTHFR) gene has been associated with Alzheimer's disease (AD) pathogenesis. Amnestic mild cognitive impairment (aMCI) represents a prodromal stage of dementia and involves a high risk of progression into AD. Although the effects of the apolipoprotein E (APOE) gene on structural alterations in aMCI have been widely investigated, the effects of MTHFR C677T and interaction effects of MTHFR × APOE genotypes on gray matter atrophy in aMCI remain largely unknown. In the present study, 60 aMCI patients and 30 healthy controls were enrolled, and voxel-based morphometry analysis was performed to inspect the effects of diagnosis, different genotypes, and their interactions on gray matter atrophy. The results showed that aMCI patients had significant gray matter atrophy involving the bilateral hippocampus, the right parahippocampal gyrus, and the left superior temporal gyrus compared with healthy controls. Besides, a substantial reduction in gray matter volume was observed in the right hippocampus region in APOE ε4 carriers from the aMCI group, compared with APOE ε4 non-carriers. A significant interaction was found between diagnosis and MTHFR C677T genotype on the right precuneus in healthy controls and aMCI patients not carrying APOE ε4 allele. Our findings may provide new evidence substantiating the genetic effects of MTHFR C677T on brain structural alternation in patients with aMCI.
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Affiliation(s)
- Mengzhe You
- Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Xia Zhou
- Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Wenwen Yin
- Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Ke Wan
- Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Wei Zhang
- Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Chenchen Li
- Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Mingxu Li
- Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Wenhao Zhu
- Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Xiaoqun Zhu
- Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Zhongwu Sun
- Department of Neurology, First Affiliated Hospital of Anhui Medical University, Hefei, China
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3
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Zhang M, Gao F, Peng L, Shen L, Zhao P, Ni B, Hou J, Huang H. Distinct clinical features and prognostic factors of hepatitis C virus-associated non-Hodgkin's lymphoma: a systematic review and meta-analysis. Cancer Cell Int 2021; 21:524. [PMID: 34627251 PMCID: PMC8502277 DOI: 10.1186/s12935-021-02230-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 09/27/2021] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Increasing evidence suggests that hepatitis C virus (HCV) infection is associated with non-Hodgkin's lymphoma (NHL). However, no clear consensus has been reached about the clinical features and effective treatment of HCV-associated NHL patients. We therefore performed a systematic review and meta-analysis to explore the clinical characteristics and effectiveness of antiviral treatment or rituximab administration among NHL patients with HCV infection. METHODS Eight electronic databases, including PubMed, OVID, EMBASE, Cochrane Library, ClinicalTrials, WANFANG, CNKI, and VIP, were searched for eligible studies up to July 31, 2021. The hazard ratio (HR) or odds ratio (OR) corresponding to the 95% confidence interval (CI) was calculated to estimate the outcomes. Publication bias was assessed by Egger's and Begg's tests. Statistical analysis was performed with RevMan 5.4 software and Stata version 15. RESULTS There were 27 shortlisted articles out of a total of 13,368 NHL patients included in the current meta-analysis. Our results demonstrated that NHL patients with HCV infection had a significantly shorter overall survival (OS: HR 1.89; 95% CI 1.42-2.51, P < 0.0001) and progression-free survival (PFS: HR 1.58; 95% CI 1.26-1.98, P < 0.0001), a lower overall response rate (ORR: OR 0.58, 95% CI 0.46-0.73, P < 0.00001) and a higher incidence of hepatic dysfunction during chemotherapy (OR 5.96; 95% CI 2.61-13.62, P < 0.0001) than NHL patients without HCV infection. HCV-positive NHL patients exhibited an advanced disease stage, an elevated level of LDH, a high-intermediate and high IPI/FLIPI risk as well as a higher incidence of spleen and liver involvement. Moreover, antiviral treatment prolonged survival (OS: HR 0.38; 95% CI 0.24-0.60, P < 0.0001), reduced disease progression [PFS/DFS (disease-free survival): HR 0.63; 95% CI 0.46-0.86, P = 0.003] and reinforced the treatment response (ORR: OR 2.62; 95% CI 1.34-5.11, P = 0.005) among the HCV-infected NHL patients. Finally, rituximab administration was associated with a favourable OS, while liver cirrhosis and low levels of albumin predicted a poor OS for HCV-positive NHL patients. CONCLUSIONS The current study provided compelling evidence about an inferior prognosis and distinct clinical characteristics among HCV-associated NHL patients. Antiviral treatment and rituximab-containing regimens were shown to be efficacious in improving the clinical outcomes of NHL patients with HCV infection.
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Affiliation(s)
- Minyue Zhang
- Division of Hematology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200127, China.,Division of Chinese Medicine, M.D. Prefectural People's Hospital, Chuxiong Yi Autonomous Prefecture, 675500, China
| | - Fei Gao
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu, 611730, China
| | - Ling Peng
- Division of Chinese Medicine, M.D. Prefectural People's Hospital, Chuxiong Yi Autonomous Prefecture, 675500, China
| | - Lijing Shen
- Division of Hematology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200127, China
| | - Peng Zhao
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu, 611730, China
| | - Beiwen Ni
- Division of Hematology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200127, China
| | - Jian Hou
- Division of Hematology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200127, China.
| | - Honghui Huang
- Division of Hematology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200127, China.
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4
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Sutovsky S, Petrovic R, Fischerova M, Haverlikova V, Ukropcova B, Ukropec J, Turcani P. Allelic Distribution of Genes for Apolipoprotein E and MTHFR in Patients with Alzheimer's Disease and Their Epistatic Interaction. J Alzheimers Dis 2021; 77:1095-1105. [PMID: 32804129 PMCID: PMC7683064 DOI: 10.3233/jad-200321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Background: Genetic risk factors play an important role in the pathogenesis of Alzheimer’s disease (AD). However, the gene-gene interaction (epistasis) between specific allelic variants is only partially understood. Objective: In our study, we examined the presence of the ɛ4 allele of apolipoprotein E (APOE) and the presence of C677T and A1298C (rs1801133 and rs1801131) polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene in patients with AD and controls. We also evaluated the epistatic interaction between MTHFR and the APOE variants. Methods: A total of 564 patients with AD and 534 cognitively unimpaired age-matched controls were involved in the study. Results: The presence of the ɛ4 allele of APOE increases the risk of developing AD in a dose-dependent manner (OR 32.7: homozygotes, 15.6: homozygotes + heterozygotes, 14.3: heterozygotes). The combination of genotypes also increases the risk of developing AD in a dose-dependent manner: OR 18.3 (APOE 4/X and 4/4 + CT rs1801133), OR 19.4 (APOE 4/X and 4/4 + CT rs1801133 + AC rs1801131), OR 22.4 (APOE 4/X and 4/4 + TT rs1801133), and OR 21.2 (APOE 4/X and 4/4 + CC rs1801131). Homozygotes for variant alleles of MTHFR as well as patients with AD had significantly higher levels of homocysteine than homozygotes for standard alleles or controls. Conclusion: Homozygotes for APOE4 and carriers of APOE4 with TT genotype of rs1801133 were found to be at the highest risk of developing AD. These findings suggest that the epistatic interaction of specific gene variants can have a significant effect on the development of AD.
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Affiliation(s)
- Stanislav Sutovsky
- 1st Department of Neurology, Faculty of Medicine, Comenius University and University Hospital, Bratislava, Slovakia
| | - Robert Petrovic
- Department of Genetics and Clinical Genetics, Institute of Medical Biology, Faculty of Medicine, Comenius University and University Hospital, Bratislava, Slovakia
| | - Maria Fischerova
- Department of Genetics and Clinical Genetics, Institute of Medical Biology, Faculty of Medicine, Comenius University and University Hospital, Bratislava, Slovakia
| | - Viera Haverlikova
- Department of Didactics in Mathematics, Physics and Informatics, Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
| | - Barbara Ukropcova
- Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia.,Institute of Pathophysiology, Faculty of Medicine, Comenius University, Bratislava, Slovakia.,Faculty of Physical Education and Sports, Comenius University, Bratislava, Slovakia
| | - Jozef Ukropec
- Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Peter Turcani
- 1st Department of Neurology, Faculty of Medicine, Comenius University and University Hospital, Bratislava, Slovakia
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Al-Thani HF, Ahmad MN, Younes S, Zayed H. Genetic Variants Associated With Alzheimer Disease in the 22 Arab Countries: A Systematic Review. Alzheimer Dis Assoc Disord 2021; 35:178-186. [PMID: 33769987 DOI: 10.1097/wad.0000000000000447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/16/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIMS Alzheimer disease (AD) is a progressive and complex neurodegenerative disease. Approximately 70% of AD risk is attributed to genetic risk factors, including variants in amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2) genes. Several studies have revealed a considerable number of candidate loci and genes for AD among different ethnic populations. However, the outcomes of these studies have been inconsistent. In this study, we aimed to investigate the spectrum of variants that are associated with the onset and development of AD among 22 Arab countries. METHODOLOGY We systematically searched 4 literature databases (Science Direct, Scopus, PubMed, and Web of Science) from the date of inception until July 2020 using various search terms to obtain all the reported genetic data on Arab AD cases. RESULTS In total, 18 studies were included, comprising a total of 2173 individuals, of whom 888 were clinically diagnosed AD patients and were genetically tested for genes and variants associated with AD. A total of 27 variants in 8 genes were found to be associated with AD. Of these variants, 17 were unique to the Arab population and 10 were shared with other ethnic groups. CONCLUSIONS There is a dearth of studies on the genetics of AD in the Arab world. There seems to be distinctive genetic and clinical susceptibility profiles for Arab patients with AD.
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Affiliation(s)
- Hissa F Al-Thani
- Department of Biomedical Science, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
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Lin M, Zhang S, Zhang M, Shi J, Zhang C, Luo R, You J, Sun J, Zhang J, Gao F. Therapeutic efficacy and safety of Kangfuxin in combination with rabeprazole in the treatment of peptic ulcer: A systematic review and meta-analysis. Medicine (Baltimore) 2020; 99:e23103. [PMID: 33235070 PMCID: PMC7710217 DOI: 10.1097/md.0000000000023103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Kangfuxin (KFX), a well-known Chinese patent medicine which extracted from Periplaneta americana, is widely used as an adjuvant in the treatment of peptic ulcers (PUs) with proton pump inhibitors (PPIs) such as rabeprazole, in China. However, no clear consensus has been reached on the efficacy for PU treatment. METHODS We searched in 7 electronic databases to find randomized controlled trials (RCTs) completed before May 31, 2020 to explore the clinical efficiency of KFX plus rabeprazole in the treatment of PU. Risk ratio (RR) corresponding to 95% confidence interval (CI) was calculated to estimate the outcomes. Publication bias was assessed by both Egger's and Begg's tests. Statistical analyses were performed using RevMan 5.4 and Stata version 10.0. RESULTS Twenty-five RCTs, comprising 2555 PU patients, were included in this study. Meta-analysis showed that, when compared with rabeprazole-based treatment alone, KFX plus rabeprazole significantly improved the healing rate (RR = 1.34, 95% CI 1.25-1.44) and overall response rate of ulcers (RR = 1.16, 95% CI 1.13-1.20), alleviated the clinical symptoms of PU (RR = 1.14, 95% CI 1.08-1.21), and reduced the recurrence of PU (RR = 0.38, 95% CI 0.24-0.61) without an increase in the occurrence of adverse events (RR = 0.92, 95% CI 0.66-1.28). CONCLUSION Our study suggests that KFX combined with rabeprazole showed positive therapeutic effects and is safe for treating PU, which may provide more reliable evidence for the clinical use of KFX in the treatment of PU.
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Affiliation(s)
- Meisi Lin
- Key Laboratory of Systematic Research of Distinctive Chinese Medicine Resources in Southwest China and Pharmacy School, Chengdu University of Traditional Chinese Medicine
- Sichuan Acupuncture School, Chengdu
| | - Siyuan Zhang
- Key Laboratory of Systematic Research of Distinctive Chinese Medicine Resources in Southwest China and Pharmacy School, Chengdu University of Traditional Chinese Medicine
- Institute of Chinese Medical Sciences, State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao
| | - Minyue Zhang
- Division of Hematology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai
| | - Jinfeng Shi
- Key Laboratory of Systematic Research of Distinctive Chinese Medicine Resources in Southwest China and Pharmacy School, Chengdu University of Traditional Chinese Medicine
| | - Chen Zhang
- Key Laboratory of Systematic Research of Distinctive Chinese Medicine Resources in Southwest China and Pharmacy School, Chengdu University of Traditional Chinese Medicine
| | - Ruifeng Luo
- Key Laboratory of Systematic Research of Distinctive Chinese Medicine Resources in Southwest China and Pharmacy School, Chengdu University of Traditional Chinese Medicine
| | - Jieshu You
- School of Basic Medical Science, Guangzhou University of Chinese Medicine, Guangzhou
| | - Jiayi Sun
- Innovative Institute of Chinese of Chinese Medicine and Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jinming Zhang
- Key Laboratory of Systematic Research of Distinctive Chinese Medicine Resources in Southwest China and Pharmacy School, Chengdu University of Traditional Chinese Medicine
| | - Fei Gao
- Key Laboratory of Systematic Research of Distinctive Chinese Medicine Resources in Southwest China and Pharmacy School, Chengdu University of Traditional Chinese Medicine
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Zuin M, Cervellati C, Trentini A, Roncon L, Guasti P, Zuliani G. Methylenetetrahydrofolate reductase C667T polymorphism and susceptibility to late-onset Alzheimer's disease in the Italian population. Minerva Med 2020; 112:365-371. [PMID: 32700867 DOI: 10.23736/s0026-4806.20.06801-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION This study is a meta-analysis of the published studies on the relationship between methylenetetrahydrofolate reductase (MTHFR) C667T polymorphism and the risk of late- onset Alzheimer 's disease (LOAD) in Italian cohorts. EVIDENCE ACQUISITION We conducted a search on the electronic databases PubMed/Medline, Web of Science and Scopus. All cohort and case-control studies investigating the association between MTHFR 677T polymorphism and LOAD in Italian population published any time to May 8, 2020 were included in the analysis. EVIDENCE SYNTHESIS From an initial screening of 136 articles, 4 were included into the systemic review. The pooled analysis based on the co-dominant model revealed that the MTHFR C677T polymorphism was associated with a significant risk of LOAD among Italian cohorts (TC vs. CC: OR=1.20, 95% CI=1.06-1.36, P=0.004, I2=0%). Conversely, the pooled analysis based on the allelic model demonstrated a non-significant relationship between the MTHFR C677T polymorphism and susceptibility to LOAD in Italians (OR: 1.25, 95% CI: 0.99-1.59, P=0.060, I2=14.6%). Moreover, Italian subjects with MTHFR 677TT genotype resulted to have a significantly increased susceptibility to LOAD (OR=1.75, 95% CI=1.23-2.50, P=0.002, I2=0%). CONCLUSIONS The present meta-analysis showed only trend of association between MTHFR C677T polymorphism and LOAD in Italian population; however, it also demonstrated an increased susceptibility of LOAD in patients having MTHFR 677TT genotype. Further studies are needed to establish whether MTHFR polymorphisms can be used as non-invasive biomarker for LOAD.
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Affiliation(s)
- Marco Zuin
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy.,Department of Cardiology, Santa Maria delle Misericordia Hospital, Rovigo, Italy
| | - Carlo Cervellati
- Department of Cardiology, Santa Maria delle Misericordia Hospital, Rovigo, Italy - crvcrl@unife
| | - Alessandro Trentini
- Department of Cardiology, Santa Maria delle Misericordia Hospital, Rovigo, Italy
| | - Loris Roncon
- Department of Cardiology, Santa Maria delle Misericordia Hospital, Rovigo, Italy
| | - Patrizia Guasti
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Giovanni Zuliani
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
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Lin S, Ma Y, Huang Z. Advanced stratification analyses in molecular association meta-analysis: methodology and application. BMC Med Res Methodol 2020; 20:147. [PMID: 32513119 PMCID: PMC7278161 DOI: 10.1186/s12874-020-01020-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 05/18/2020] [Indexed: 12/04/2022] Open
Abstract
Background Stratification analyses have been widely utilized in molecular association meta-analyses to estimate the interaction between genetic and environmental factors or to control for the confounding variables linked to a disease. Two calculation methods utilized in practical research, which are known as the variants of factorial stratification analysis and confounder-controlling stratification analysis in our nomenclature, have been applied in previous studies, but none of which have presented a methodology and application for these analyses. Methods In this paper, these two approaches are integrated and further developed into a standard procedure for stratification analysis. We first propose the advanced statistical methodology and theoretical algorithm of these three types of stratification analysis and then provide two example applications in meta-analyses of molecular association to illustrate the computing processes and interpretation of the results. Results The standard stratification analysis synthesizes the advantages of the first two practical methods, including identifying and controlling confounding moderators or revealing and calculating gene-environment interactions, to efficiently classify the real influence of various investigated factors on a disease in the general population. Additional challenges concerning this method and their potential solutions are also discussed, such as the approach to utilizing only the partially stratified data available in meta-research practice. Conclusions The standard stratification method will be extensively applicable to rapidly expanding future research on the complex relationships among genetics, environment, disease, and other variables.
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Affiliation(s)
- Shuhuang Lin
- Key Laboratory of Big Data Mining and Precision Drug Design of Guangdong Medical University, Research Platform Service Management Center, Guangdong Medical University, Dongguan, 523808, Guangdong, China.,The Second School of Clinical Medicine, Guangdong Medical University, Dongguan, 523808, Guangdong, China
| | - Yukun Ma
- The Second School of Clinical Medicine, Guangdong Medical University, Dongguan, 523808, Guangdong, China
| | - Zunnan Huang
- Key Laboratory of Big Data Mining and Precision Drug Design of Guangdong Medical University, Research Platform Service Management Center, Guangdong Medical University, Dongguan, 523808, Guangdong, China. .,Institute of Marine Biomedical Research, Guangdong Medical University, Zhanjiang, 524023, Guangdong, China.
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Yi J, Xiao L, Zhou SQ, Zhang WJ, Liu BY. The C677T Polymorphism of the Methylenetetrahydrofolate Reductase Gene and Susceptibility to Late-onset Alzheimer's Disease. Open Med (Wars) 2019; 14:32-40. [PMID: 30631824 PMCID: PMC6325648 DOI: 10.1515/med-2019-0006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 11/28/2018] [Indexed: 02/07/2023] Open
Abstract
Folate metabolism makes a crucial contribution towards late-onset Alzheimer's disease (LOAD). Moreover, methylenetetrahydrofolate reductase (MTHFR) constitutes the primary enzyme of the folate pathway. We hypothesize that there is an association of C677T polymorphism in the MTHFR gene with the susceptibility to LOAD. Previous published research has investigated the link between the MTHFR C677T polymorphisms and LOAD susceptibility; nevertheless, the findings have continued to be not only controversial, but also indecisive. Accordingly, we carried out the present meta-analysis for the assessment of the potential link that exists between the MTHFR C677T polymorphism and the susceptibility to LOAD. Furthermore, we carried out a literature search of the PubMed, EMBASE, Cochrane Library, and WanFang database up to August 10, 2018. The odds ratios (ORs) with the respective 95% confidence interval (95%CI) were put to use for the evaluation of the robustness of the link of the MTHFR C677T polymorphism with the vulnerability to LOAD. All statistical analyses were carried out using STATA 15.0. An aggregate of 14 case-control research works was retrieved, involving 2,467 LOAD patients as well as 2,877 controls. We found that a substantial link exists between C677T polymorphism and LOAD risk in a codominant framework (TC vs. CC: OR=1.22, 95%CI=1.00-1.49, P=0.049). In addition to the stratified analysis based on ethnicity, which suggested that C677T polymorphism was likely linked only to an augmented threat of LOAD in Asians, it did not exist among Caucasians. Furthermore, in the subgroup analysis carried out using APOE ɛ4 status, a substantial increase in the susceptibility to LOAD was detected in APOE ɛ4 carriers as well as non-APOE ɛ4 carriers. In sum, the current meta-analysis revealed that MTHFR C677T polymorphism was associated with susceptibility to LOAD. Further extensive case-control studies are required.
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Affiliation(s)
- Jian Yi
- Key Laboratory of Internal Medicine, The Frist Hospital Hunan University of Traditional Chinese Medicine, Changsha 410007, Hunan Province, P.R. China
| | - Lan Xiao
- Hunan University of Traditional Chinese Medicine, Changsha 410208, Hunan Province, P.R. China
| | - Sheng-Qiang Zhou
- Hunan University of Traditional Chinese Medicine, Changsha 410208, Hunan Province, P.R. China
| | - Wen-Jiang Zhang
- Yiyang Medicine College, Yiyang 413000, Hunan Province, P.R. China
| | - Bai-Yan Liu
- Key Laboratory of Internal Medicine, The Frist Hospital Hunan University of Traditional Chinese Medicine, Changsha 410007, Hunan Province, P.R. China.,Yiyang Medicine College, Yiyang 413000, Hunan Province, P.R. China
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10
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Stoccoro A, Tannorella P, Salluzzo MG, Ferri R, Romano C, Nacmias B, Siciliano G, Migliore L, Coppedè F. The Methylenetetrahydrofolate Reductase C677T Polymorphism and Risk for Late-Onset Alzheimer's disease: Further Evidence in an Italian Multicenter Study. J Alzheimers Dis 2018; 56:1451-1457. [PMID: 28211809 DOI: 10.3233/jad-161081] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND A functional polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene, namely C677T (rs1801133), results in increased Hcy levels and has been associated with risk of late-onset Alzheimer's disease (LOAD). Many investigators reported association between rs1801133 and LOAD risk in Asian populations and in carriers of the apolipoprotein E (APOE) ɛ4 allele, but recent meta-analyses suggest a contribution also in other populations, including Caucasians and/or northern Africans. OBJECTIVE To further address this issue, we performed a relatively large case-control study, including 581 LOAD patients and 468 matched controls of Italian origin. APOE data were available for a subgroup of almost 600 subjects. METHODS Genotyping for rs1801133 was performed with PCR-RFLP techniques. RESULTS In the total population, the MTHFR 677T allele (OR = 1.20; 95% CI = 1.01-1.43) and carriers of the MTHFR 677T allele (CT+TT versus CC: OR = 1.34; 95% CI = 1.03-1.73) resulted in increased LOAD risk. Similarly, in APOEɛ4 carriers, we observed an increased frequency of MTHFR 677CT carriers (CT versus CC: OR = 2.82; 95% CI = 1.25-6.32). Very interestingly, also in non-APOEɛ4 carriers, both MTHFR 677T allele (OR = 1.38; 95% CI = 1.03-1.85) and MTHFR 677TT genotype (OR = 2.08; 95% CI = 1.11-3.90) were associated with LOAD. All these associations survived after corrections for age, gender, and multiple testing. CONCLUSIONS The present results suggest that the MTHFR C677T polymorphism is likely a LOAD risk factor in our cohort, either in APOEɛ4 or in non-APOEɛ4 carriers.
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Affiliation(s)
- Andrea Stoccoro
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Pisa, Italy.,Doctoral School in Genetics Oncology and Clinical Medicine, University of Siena, Siena, Italy
| | - Pierpaola Tannorella
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Pisa, Italy
| | - Maria Grazia Salluzzo
- IRCCS, Oasi Maria SS Institute for Research on Mental Retardation and Brain Aging, Troina, Italy
| | - Raffaele Ferri
- IRCCS, Oasi Maria SS Institute for Research on Mental Retardation and Brain Aging, Troina, Italy
| | - Corrado Romano
- IRCCS, Oasi Maria SS Institute for Research on Mental Retardation and Brain Aging, Troina, Italy
| | - Benedetta Nacmias
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Gabriele Siciliano
- Department of Clinical and Experimental Medicine, University of Pisa, Neurological Clinic, Pisa, Italy
| | - Lucia Migliore
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood Nutraceuticals and Food for Health, University of Pisa, Pisa, Italy
| | - Fabio Coppedè
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood Nutraceuticals and Food for Health, University of Pisa, Pisa, Italy
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11
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Roostaei T, Felsky D, Nazeri A, De Jager PL, Schneider JA, Bennett DA, Voineskos AN. Genetic influence of plasma homocysteine on Alzheimer's disease. Neurobiol Aging 2018; 62:243.e7-243.e14. [PMID: 29102475 PMCID: PMC6953632 DOI: 10.1016/j.neurobiolaging.2017.09.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/30/2017] [Accepted: 09/29/2017] [Indexed: 12/17/2022]
Abstract
Observational studies have consistently reported elevated plasma homocysteine as a risk factor for Alzheimer's disease (AD). However, results from clinical trials of homocysteine-lowering treatments are inconsistent. This discrepancy may be explained by a lack of causal association between homocysteine and AD. Mendelian randomization studies have the potential to provide insight into the causality of this association through studying the effect of genetic predisposition to high homocysteine on AD. Our analyses using summarized (n = 54,162) and individual participant (n = 6987) data from Caucasian participants did not show an effect of plasma homocysteine genetic risk on susceptibility to AD. Although with smaller sample sizes, further subanalyses also did not support an effect of genetically determined plasma homocysteine on cognitive impairment and decline, beta-amyloid and tau pathology and gray matter atrophy in AD. However, we found associations with tau tangle burden (n = 251) and gray matter atrophy (n = 605) in cognitively normal elderly. Our results do not support a causal association between elevated homocysteine and risk, severity, and progression of AD. However, the relationship between genetically determined homocysteine and brain pathology in cognitively normal elderly requires further exploration.
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Affiliation(s)
- Tina Roostaei
- Kimel Family Translational Imaging-Genetics Laboratory, Research Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Cell Circuits Program, Broad Institute, Cambridge, MA, USA; Center for Translational and Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Daniel Felsky
- Cell Circuits Program, Broad Institute, Cambridge, MA, USA; Center for Translational and Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Arash Nazeri
- Kimel Family Translational Imaging-Genetics Laboratory, Research Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Philip L De Jager
- Cell Circuits Program, Broad Institute, Cambridge, MA, USA; Center for Translational and Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Julie A Schneider
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA; Department of Pathology, Rush University Medical Center, Chicago, IL, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Aristotle N Voineskos
- Kimel Family Translational Imaging-Genetics Laboratory, Research Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Underserved Populations Program, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
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12
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Lin S, Liu X, Yao B, Huang Z. Controlling for confounding factors and revealing their interactions in genetic association meta-analyses: a computing method and application for stratification analyses. Oncotarget 2018; 9:12125-12136. [PMID: 29552297 PMCID: PMC5844733 DOI: 10.18632/oncotarget.24335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 01/24/2018] [Indexed: 11/25/2022] Open
Abstract
Subgroup and stratification analyses have been widely applied in genetic association studies to compare the effects of different factors or control for the effects of the confounding variables associated with a disease. However, studies have not systematically provided application standards and computing methods for stratification analyses. Based on the Mantel-Haenszel and Inverse-Variant approaches and two practical computing methods described in previous studies, we propose a standard stratification method for meta-analyses that contains two sequential steps: factorial stratification analysis and confounder-controlling stratification analysis. Examples of genetic association meta-analyses are used to illustrate these points. The standard stratification analysis method identifies interacting effects on investigated factors and controls for confounding variables, and this method effectively reveals the real effects of these factors and confounding variables on a disease in an overall study population. We also discuss important issues concerning stratification for meta-analyses, such as conceptual confusion between subgroup and stratification analyses, and incorrect calculations previously used for factorial stratification analyses. This standard stratification method will have extensive applications in future research for increasing studies on the complicated relationships between genetics and disease.
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Affiliation(s)
- Shuhuang Lin
- Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Dongguan Scientific Research Center, Guangdong Medical University, Dongguan, Guangdong 523808, China.,The Second School of Clinical Medicine, Guangdong Medical University, Dongguan, Guangdong 523808, China
| | - Xu Liu
- Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Dongguan Scientific Research Center, Guangdong Medical University, Dongguan, Guangdong 523808, China.,The Second School of Clinical Medicine, Guangdong Medical University, Dongguan, Guangdong 523808, China
| | - Bin Yao
- Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Dongguan Scientific Research Center, Guangdong Medical University, Dongguan, Guangdong 523808, China.,The Second School of Clinical Medicine, Guangdong Medical University, Dongguan, Guangdong 523808, China
| | - Zunnan Huang
- Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Dongguan Scientific Research Center, Guangdong Medical University, Dongguan, Guangdong 523808, China.,Institute of Marine Biomedical Research, Guangdong Medical University, Zhanjiang, Guangdong 524023, China
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13
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Chang CC, Tsai SJ, Chen NC, Huang CW, Hsu SW, Chang YT, Liu ME, Chang WN, Tsai WC, Lee CC. Catechol-O-Methyltransferase Val158Met Polymorphism on Striatum Structural Covariance Networks in Alzheimer's Disease. Mol Neurobiol 2017; 55:4637-4649. [PMID: 28707072 PMCID: PMC5948254 DOI: 10.1007/s12035-017-0668-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 06/20/2017] [Indexed: 01/23/2023]
Abstract
The catechol-O-methyltransferase enzyme metabolizes dopamine in the prefrontal axis, and its genetic polymorphism (rs4680; Val158Met) is a known determinant of dopamine signaling. In this study, we investigated the possible structural covariance networks that may be modulated by this functional polymorphism in patients with Alzheimer’s disease. Structural covariance networks were constructed by 3D T1 magnetic resonance imaging. The patients were divided into two groups: Met-carriers (n = 91) and Val-homozygotes (n = 101). Seed-based analysis was performed focusing on triple-network models and six striatal networks. Neurobehavioral scores served as the major outcome factors. The role of seed or peak cluster volumes, or a covariance strength showing Met-carriers > Val-homozygotes were tested for the effect on dopamine. Clinically, the Met-carriers had higher mental manipulation and hallucination scores than the Val-homozygotes. The volume-score correlations suggested the significance of the putaminal seed in the Met-carriers and caudate seed in the Val-homozygotes. Only the dorsal-rostral and dorsal-caudal putamen interconnected peak clusters showed covariance strength interactions (Met-carriers > Val-homozygotes), and the peak clusters also correlated with the neurobehavioral scores. Although the triple-network model is important for a diagnosis of Alzheimer’s disease, our results validated the role of the dorsal-putaminal-anchored network by the catechol-O-methyltransferase Val158Met polymorphism in predicting the severity of cognitive and behavior in subjects with Alzheimer’s disease.
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Affiliation(s)
- Chiung-Chih Chang
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, #123, Ta-Pei Road, Niaosung, Kaohsiung, 833, Taiwan.
| | - Shih-Jen Tsai
- Psychiatric Department, Taipei Veterans General Hospital, Taipei, Taiwan.,Psychiatric Division, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Nai-Ching Chen
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, #123, Ta-Pei Road, Niaosung, Kaohsiung, 833, Taiwan
| | - Chi-Wei Huang
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, #123, Ta-Pei Road, Niaosung, Kaohsiung, 833, Taiwan
| | - Shih-Wei Hsu
- Department of Radiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Ya-Ting Chang
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, #123, Ta-Pei Road, Niaosung, Kaohsiung, 833, Taiwan
| | - Mu-En Liu
- Psychiatric Department, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Wen-Neng Chang
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, #123, Ta-Pei Road, Niaosung, Kaohsiung, 833, Taiwan
| | - Wan-Chen Tsai
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, #123, Ta-Pei Road, Niaosung, Kaohsiung, 833, Taiwan
| | - Chen-Chang Lee
- Department of Radiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
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14
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Risk factors associated with the onset and progression of Alzheimer’s disease: A systematic review of the evidence. Neurotoxicology 2017; 61:143-187. [DOI: 10.1016/j.neuro.2017.03.006] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 03/22/2017] [Indexed: 12/25/2022]
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15
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Tian S, Han J, Huang R, Sun J, Cai R, Shen Y, Wang S. Increased Plasma Homocysteine Level is Associated with Executive Dysfunction in Type 2 Diabetic Patients with Mild Cognitive Impairment. J Alzheimers Dis 2017; 58:1163-1173. [PMID: 28550262 DOI: 10.3233/jad-170162] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Sai Tian
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing, PR China
- Medical School of Southeast University, Nanjing, PR China
| | - Jing Han
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing, PR China
| | - Rong Huang
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing, PR China
| | - Jie Sun
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing, PR China
| | - Rongrong Cai
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing, PR China
| | - Yanjue Shen
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing, PR China
| | - Shaohua Wang
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, Nanjing, PR China
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16
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Chang YT, Hsu SW, Tsai SJ, Chang YT, Huang CW, Liu ME, Chen NC, Chang WN, Hsu JL, Lee CC, Chang CC. Genetic effect of MTHFR C677T polymorphism on the structural covariance network and white-matter integrity in Alzheimer's disease. Hum Brain Mapp 2017; 38:3039-3051. [PMID: 28342207 DOI: 10.1002/hbm.23572] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/07/2017] [Accepted: 03/03/2017] [Indexed: 11/10/2022] Open
Abstract
The 677 C to T transition in the MTHFR gene is a genetic determinant for hyperhomocysteinemia. We investigated whether this polymorphism modulates gray matter (GM) structural covariance networks independently of white-matter integrity in patients with Alzheimer's disease (AD). GM structural covariance networks were constructed by 3D T1-magnetic resonance imaging and seed-based analysis. The patients were divided into two genotype groups: C homozygotes (n = 73) and T carriers (n = 62). Using diffusion tensor imaging and white-matter parcellation, 11 fiber bundle integrities were compared between the two genotype groups. Cognitive test scores were the major outcome factors. The T carriers had higher homocysteine levels, lower posterior cingulate cortex GM volume, and more clusters in the dorsal medial lobe subsystem showing stronger covariance strength. Both posterior cingulate cortex seed and interconnected peak cluster volumes predicted cognitive test scores, especially in the T carriers. There were no between-group differences in fiber tract diffusion parameters. The MTHFR 677T polymorphism modulates posterior cingulate cortex-anchored structural covariance strength independently of white matter integrities. Hum Brain Mapp 38:3039-3051, 2017. © 2017 The Authors Human Brain Mapping Published Wiley by Periodicals, Inc.
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Affiliation(s)
- Yu-Tzu Chang
- Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shih-Wei Hsu
- Department of Radiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Shih-Jen Tsai
- Psychiatric Department of Taipei Veterans General Hospital, Taipei, Taiwan.,Psychiatric Division, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Ya-Ting Chang
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Chi-Wei Huang
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Mu-En Liu
- Psychiatric Department of Taipei Veterans General Hospital, Taipei, Taiwan
| | - Nai-Ching Chen
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Wen-Neng Chang
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Jung-Lung Hsu
- Section of Dementia and Cognitive Impairment, Department of Neurology, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Chen-Chang Lee
- Department of Radiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Chiung-Chih Chang
- Department of Neurology, Cognition and Aging Center, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
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17
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Hu Q, Teng W, Li J, Hao F, Wang N. Homocysteine and Alzheimer's Disease: Evidence for a Causal Link from Mendelian Randomization. J Alzheimers Dis 2017; 52:747-56. [PMID: 27031476 DOI: 10.3233/jad-150977] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND/OBJECTIVE The relationship between plasma homocysteine (Hcy) levels and Alzheimer's disease (AD) has been studied for many years, but remains controversial. While a recent meta-analysis of epidemiological studies, which included observational studies, indicated that homocysteine may be a risk factor for AD, there remains a need to further demonstrate this link due to the large degree of heterogeneity between studies. Epidemiological studies have certain limitations, as their results can be affected by confounding factors and reverse causation. In this study, we evaluated the relationship between plasma homocysteine and AD by using a Mendelian randomization method to avoid problems of confounding bias and reverse causality. METHODS We searched the PubMed and EMBASE databases for reports regarding the MTHFR C677T polymorphism (rs1801133) from the time of their inception to September 2015. These reports were combined with related observational studies, and used to evaluate the effect of MTHFR C677T (rs1801133) on the risk for AD. A recent meta-analysis of genome-wide association studies had previously suggested a relationship between homocysteine and MTHFR C677T (rs 1801133). RESULTS Our met-analysis included 34 studies with 9397 subjects, and demonstrated a significant relationship between plasma total homocysteine levels and the risk for AD (OR = 3.37; 95% CI = 1.90-5.95; p = 2.9×10-5). CONCLUSION Our meta-analysis demonstrated a causal link between plasma total homocysteine and the risk for AD, and provides a new insight into the etiology and prevention of AD.
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Ye Q, Bai F, Zhang Z. Shared Genetic Risk Factors for Late-Life Depression and Alzheimer's Disease. J Alzheimers Dis 2017; 52:1-15. [PMID: 27060956 DOI: 10.3233/jad-151129] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Considerable evidence has been reported for the comorbidity between late-life depression (LLD) and Alzheimer's disease (AD), both of which are very common in the general elderly population and represent a large burden on the health of the elderly. The pathophysiological mechanisms underlying the link between LLD and AD are poorly understood. Because both LLD and AD can be heritable and are influenced by multiple risk genes, shared genetic risk factors between LLD and AD may exist. OBJECTIVE The objective is to review the existing evidence for genetic risk factors that are common to LLD and AD and to outline the biological substrates proposed to mediate this association. METHODS A literature review was performed. RESULTS Genetic polymorphisms of brain-derived neurotrophic factor, apolipoprotein E, interleukin 1-beta, and methylenetetrahydrofolate reductase have been demonstrated to confer increased risk to both LLD and AD by studies examining either LLD or AD patients. These results contribute to the understanding of pathophysiological mechanisms that are common to both of these disorders, including deficits in nerve growth factors, inflammatory changes, and dysregulation mechanisms involving lipoprotein and folate. Other conflicting results have also been reviewed, and few studies have investigated the effects of the described polymorphisms on both LLD and AD. CONCLUSION The findings suggest that common genetic pathways may underlie LLD and AD comorbidity. Studies to evaluate the genetic relationship between LLD and AD may provide insights into the molecular mechanisms that trigger disease progression as the population ages.
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Wu SM, Chen ZF, Young L, Shiao SPK. Meta-Prediction of the Effect of Methylenetetrahydrofolate Reductase Polymorphisms and Air Pollution on Alzheimer's Disease Risk. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14010063. [PMID: 28085050 PMCID: PMC5295314 DOI: 10.3390/ijerph14010063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/28/2016] [Accepted: 01/05/2017] [Indexed: 01/16/2023]
Abstract
Background: Alzheimer's disease (AD) is a significant public health issue. AD has been linked with methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, but the findings have been inconsistent. The purpose of this meta-predictive analysis is to examine the associations between MTHFR polymorphisms and epigenetic factors, including air pollution, with AD risk using big data analytics approaches. Methods and Results: Forty-three studies (44 groups) were identified by searching various databases. MTHFR C677T TT and CT genotypes had significant associations with AD risk in all racial populations (RR = 1.13, p = 0.0047; and RR = 1.12, p < 0.0001 respectively). Meta-predictive analysis showed significant increases of percentages of MTHFR C677T polymorphism with increased air pollution levels in both AD case group and control group (p = 0.0021-0.0457); with higher percentages of TT and CT genotypes in the AD case group than that in the control group with increased air pollution levels. Conclusions: The impact of MTHFR C677T polymorphism on susceptibility to AD was modified by level of air pollution. Future studies are needed to further examine the effects of gene-environment interactions including air pollution on AD risk for world populations.
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Affiliation(s)
- Suh-Mian Wu
- Department of Nursing, Yuanpei University of Medical Technology, No.306, Yuanpei Street, Hsinchu 30015, Taiwan.
- Graduate Institute of Clinical Medical Sciences, Chang Gung University, No.259, Wenhua 1st Rd., Guishan Dist., Taoyuan City 33302, Taiwan.
| | - Zhao-Feng Chen
- Department of Nursing, Yuanpei University of Medical Technology, No.306, Yuanpei Street, Hsinchu 30015, Taiwan.
| | - Lufei Young
- College of Nursing, Augusta University (Previously Georgia Regents University), 987 St. Sebastian Way, EC 4505, Augusta, GA 30912, USA.
| | - S Pamela K Shiao
- College of Nursing, Augusta University (Previously Georgia Regents University), 987 St. Sebastian Way, EC 4505, Augusta, GA 30912, USA.
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20
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Troesch B, Weber P, Mohajeri MH. Potential Links between Impaired One-Carbon Metabolism Due to Polymorphisms, Inadequate B-Vitamin Status, and the Development of Alzheimer's Disease. Nutrients 2016; 8:E803. [PMID: 27973419 PMCID: PMC5188458 DOI: 10.3390/nu8120803] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/06/2016] [Accepted: 12/07/2016] [Indexed: 12/24/2022] Open
Abstract
Alzheimer's disease (AD) is the major cause of dementia and no preventive or effective treatment has been established to date. The etiology of AD is poorly understood, but genetic and environmental factors seem to play a role in its onset and progression. In particular, factors affecting the one-carbon metabolism (OCM) are thought to be important and elevated homocysteine (Hcy) levels, indicating impaired OCM, have been associated with AD. We aimed at evaluating the role of polymorphisms of key OCM enzymes in the etiology of AD, particularly when intakes of relevant B-vitamins are inadequate. Our review indicates that a range of compensatory mechanisms exist to maintain a metabolic balance. However, these become overwhelmed if the activity of more than one enzyme is reduced due to genetic factors or insufficient folate, riboflavin, vitamin B6 and/or vitamin B12 levels. Consequences include increased Hcy levels and reduced capacity to synthetize, methylate and repair DNA, and/or modulated neurotransmission. This seems to favor the development of hallmarks of AD particularly when combined with increased oxidative stress e.g., in apolipoprotein E (ApoE) ε4 carriers. However, as these effects can be compensated at least partially by adequate intakes of B-vitamins, achieving optimal B-vitamin status for the general population should be a public health priority.
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Affiliation(s)
- Barbara Troesch
- DSM Nutritional Products Ltd., Wurmisweg 576, Kaiseraugst 4303, Switzerland.
| | - Peter Weber
- DSM Nutritional Products Ltd., Wurmisweg 576, Kaiseraugst 4303, Switzerland.
| | - M Hasan Mohajeri
- DSM Nutritional Products Ltd., Wurmisweg 576, Kaiseraugst 4303, Switzerland.
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21
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Rai V. Association of methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism with autism: evidence of genetic susceptibility. Metab Brain Dis 2016; 31:727-35. [PMID: 26956130 DOI: 10.1007/s11011-016-9815-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/23/2016] [Indexed: 01/18/2023]
Abstract
Autism (MIM 209850) is a heterogeneous neurodevelopmental disease that manifests within the first 3 years of life. Numerous articles reported that dysfunctional folate-methionine pathway enzymes may play an important role in the pathophysiology of autism. Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme of this pathway and MTHFR C677T polymorphism reported as risk factor for autism in several case control studies. However, controversial reports were also published. Hence the present meta-analysis was designed to investigate the relationship of the MTHFR C677T polymorphism with the risk of autism. Electronic databases were searched for case control studies with following search terms - 'MTHFR', 'C677T', in combination with 'Autism'. Pooled OR with its corresponding 95 % CI was calculated and used as association measure to investigate the association between MTHFR C677T polymorphism and risk of autism. Total of thirteen studies were found suitable for the inclusion in the present meta-analysis, which comprises 1978 cases and 7257 controls. Meta-analysis using all four genetic models showed significant association between C677T polymorphism and autism (ORTvs.C = 1.48; 95 % CI: 1.18-1.86; P = 0.0007; ORTT + CT vs. CC = 1.70, 95 % CI = 0.96-2.9, p = 0.05; ORTT vs. CC = 1.84, 95 % CI = 1.12-3.02, p = 0.02; ORCT vs.CC = 1.60, 95 % CI = 1.2-2.1, p = 0.003; ORTT vs.CT+CC = 1.5, 95 % CI = 1.02-2.2, p = 0.03). In total 13 studies, 9 studies were from Caucasian population and 4 studies were from Asian population. The association between C677T polymorphism and autism was significant in Caucasian (ORTvs.C = 1.43; 95 % CI = 1.1-1.87; p = 0.009) and Asian population (ORTvs.C = 1.68; 95 % CI = 1.02-2.77; p = 0.04) using allele contrast model. In conclusion, present meta-analysis strongly suggested a significant association of the MTHFR C677T polymorphism with autism.
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Affiliation(s)
- Vandana Rai
- VBS Purvanchal University, Jaunpur, 222003, UP, India.
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Yadav U, Kumar P, Gupta S, Rai V. Role of MTHFR C677T gene polymorphism in the susceptibility of schizophrenia: An updated meta-analysis. Asian J Psychiatr 2016; 20:41-51. [PMID: 27025471 DOI: 10.1016/j.ajp.2016.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 12/31/2015] [Accepted: 02/05/2016] [Indexed: 11/19/2022]
Abstract
Methylenetetrahydrofolate reductase (MTHFR) is the key enzyme of folate/homocysteine metabolic pathway. C677T polymorphism of MTHFR gene was reported as risk factor for congenital defects, metabolic and neuropsychiatric disorders. Numerous case-control studies investigated C677T polymorphism as risk factor for schizophrenia but results of these studies were contradictory. To draw a conclusion, a meta-analysis of all available case-control studies was performed. PubMed, Google Scholar, Springer Link and Elsevier databases were searched for eligible case-control studies. Pooled odds ratio with 95%CI was used as an association measure and all statistical analyses were performed by Open Meta-Analyst and MIX software. Total 38 studies with 10,069 cases and 13,372 controls were included in the present meta-analysis. Results of meta-analysis showed significant associated between C677T polymorphism and risk of schizophrenia (ORTvsC=1.18, 95%CI=1.10-1.27, p=<0.001; ORCTvsCC=1.10, 95%CI=1.04-1.17, p=<0.001; ORTTvsCC=1.40, 95%CI=1.20-1.64, p=<0.001; ORTT+CTvsCC=1.19, 95%CI=1.09-1.30, p=<0.001). We also performed subgroup and sensitivity analyses. Subgroup analysis was done according to ethnicity and significant association was found between C677T polymorphism and risk of schizophrenia in all three ethnic populations-African (OR=2.51; 95%CI=1.86-3.40; p=<0.001), Asian (OR=1.21; 95%CI=1.10-1.33; p=<0.001) and Caucasian (OR=1.07; 95%CI=1.01-1.14; p=0.01). In conclusion the results of the present meta-analysis suggested that the MTHFR C677T polymorphism is a risk factor for schizophrenia.
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Affiliation(s)
- Upendra Yadav
- Human Molecular Genetics Laboratory, Department of Biotechnology, VBS Purvanchal University, Jaunpur 222 003, UP, India
| | - Pradeep Kumar
- Human Molecular Genetics Laboratory, Department of Biotechnology, VBS Purvanchal University, Jaunpur 222 003, UP, India
| | - Sanjay Gupta
- Department of Psychiatry, IMS, Banaras Hindu University, Varanasi, India
| | - Vandana Rai
- Human Molecular Genetics Laboratory, Department of Biotechnology, VBS Purvanchal University, Jaunpur 222 003, UP, India.
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Eszlari N, Kovacs D, Petschner P, Pap D, Gonda X, Elliott R, Anderson IM, Deakin JFW, Bagdy G, Juhasz G. Distinct effects of folate pathway genes MTHFR and MTHFD1L on ruminative response style: a potential risk mechanism for depression. Transl Psychiatry 2016; 6:e745. [PMID: 26926881 PMCID: PMC4872445 DOI: 10.1038/tp.2016.19] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 12/14/2015] [Accepted: 01/14/2016] [Indexed: 12/11/2022] Open
Abstract
Alterations in the folate pathway have been related to both major depression and cognitive inflexibility; however, they have not been investigated in the genetic background of ruminative response style, which is a form of perseverative cognition and a risk factor for depression. In the present study, we explored the association of rumination (measured by the Ruminative Responses Scale) with polymorphisms of two distinct folate pathway genes, MTHFR rs1801133 (C677T) and MTHFD1L rs11754661, in a combined European white sample from Budapest, Hungary (n=895) and Manchester, United Kingdom (n=1309). Post hoc analysis investigated whether the association could be replicated in each of the two samples, and the relationship between folate pathway genes, rumination, lifetime depression and Brief Symptom Inventory depression score. Despite its functional effect on folate metabolism, the MTHFR rs1801133 showed no effect on rumination. However, the A allele of MTHFD1L rs11754661 was significantly associated with greater rumination, and this effect was replicated in both the Budapest and Manchester samples. In addition, rumination completely mediated the effects of MTHFD1L rs11754661 on depression phenotypes. These findings suggest that the MTHFD1L gene, and thus the C1-THF synthase enzyme of the folate pathway localized in mitochondria, has an important effect on the pathophysiology of depression through rumination, and maybe via this cognitive intermediate phenotype on other mental and physical disorders. Further research should unravel whether the reversible metabolic effect of MTHFD1L is responsible for increased rumination or other long-term effects on brain development.
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Affiliation(s)
- N Eszlari
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary,MTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary,Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, 1089 Budapest, Nagyvarad ter 4, Budapest 1089, Hungary. E-mail:
| | - D Kovacs
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary,MTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
| | - P Petschner
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary,MTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
| | - D Pap
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary,MTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
| | - X Gonda
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary,MTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary,Department of Clinical and Theoretical Mental Health, Kutvolgyi Clinical Center, Semmelweis University, Budapest, Hungary
| | - R Elliott
- Neuroscience and Psychiatry Unit, School of Community Based Medicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK,Manchester Academic Health Sciences Centre, Manchester, UK
| | - I M Anderson
- Neuroscience and Psychiatry Unit, School of Community Based Medicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK,Manchester Academic Health Sciences Centre, Manchester, UK
| | - J F W Deakin
- Neuroscience and Psychiatry Unit, School of Community Based Medicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK,Manchester Academic Health Sciences Centre, Manchester, UK,Manchester Mental Health and Social Care Trust, Manchester, UK
| | - G Bagdy
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary,MTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
| | - G Juhasz
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary,MTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary,Neuroscience and Psychiatry Unit, School of Community Based Medicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK,Manchester Academic Health Sciences Centre, Manchester, UK,MTA-SE-NAP B Genetic Brain Imaging Migraine Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
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Rai V. Methylenetetrahydrofolate Reductase C677T Polymorphism and Recurrent Pregnancy Loss Risk in Asian Population: A Meta-analysis. Indian J Clin Biochem 2016; 31:402-13. [PMID: 27605737 DOI: 10.1007/s12291-016-0554-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 01/20/2016] [Indexed: 01/15/2023]
Abstract
The C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene was implicated to be associated with thrombophilia due to its role in catalyzing the formation of 5-methylenetetrahydrofolate, a co-substrate for the conversion of homocysteine to methionine. Several case-control studies were investigated MTHFR C677T polymorphism as risk for recurrent pregnancy loss (RPL). These studies rendered contradictory results, some indicating that the polymorphism is associated with the risk of RPL whereas others concluded there is no association. To shed light on these inconclusive findings, a meta-analysis of all available studies published from Asian population relating the C677T polymorphism to the risk of RPL was conducted. The following electronic databases were searched without language restrictions: PubMed, Google Scholars, Elsevier and Springer Link up to December, 2015. Meta-analysis was performed using MetaAnalyst and Mix version 1.7. Meta-analysis results suggested that MTHFR C677T polymorphism contributed to the increased RPL risk in Asian population using all five genetic models (for T vs. C: OR 1.35, 95 % CI 1.09-1.68, p = 0.009; for TT + CT vs. CC: OR 1.44, 95 % CI 1.14-1.82, p = 0.006; for CT vs. CC: OR 1.39, 95 % CI 1.07-1.8, p = 0.01; for TT vs. CC: OR 1.79, 95 % CI 1.23.2.6, p = 0.007; for TT vs. CT + CC: OR 1.61, 95 % CI 1.02-2.56, p = 0.04). In conclusion, this meta-analysis demonstrates a strong association between the MTHFR C677T variant and RPL in Asian population and raising the importance of the use of folate in its treatment and prevention.
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Affiliation(s)
- Vandana Rai
- Human Molecular Genetics Laboratory, Department of Biotechnology, VBS Purvanchal University, Jaunpur, UP 222003 India
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Methylenetetrahydrofolate Reductase (MTHFR) C677T Polymorphism and Alzheimer Disease Risk: a Meta-Analysis. Mol Neurobiol 2016; 54:1173-1186. [PMID: 26820674 DOI: 10.1007/s12035-016-9722-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 01/13/2016] [Indexed: 01/08/2023]
Abstract
Methylenetetrahydrofolate reductase (MTHFR) is key enzyme of folate/homocysteine pathway. Case control association studies on MTHFR C677T polymorphism and Alzheimer's disease (AD) have been repeatedly performed over the last two decades, but the results are inconclusive. The aim of the present study was to assess the risk of MTHFR C677T polymorphism for AD. Forty-one studies were identified by a search of PubMed, Google Scholar, Elsevier, and Springer Link databases, up to January 2015. Odds ratios (ORs) with corresponding 95 % confidence interval (CI) were calculated using fixed effect model or random effect model. The subgroup analyses based on ethnicity were performed. MTHFR C677T polymorphism had a significant association with susceptibility to AD in all genetic models (for T vs C OR = 1.29, 95 % CI = 1.07-1.56, p = 0.003; for TT + CT vs CC OR = 1.29, 95 % CI = 1.19-1.40, p = 0.0004; for TT vs CC OR = 1.31, 95 % CI = 1.16-1.48, p = 0.001; for CT vs CC OR = 1.24, 95 % CI = 1.13-1.35, p < 0.004; and for TT vs CT + CC OR = 1.13, 95 % CI = 1.00-1.28, p = 0.02). Results of present meta-analysis supported that the MTHFR C677T polymorphism was associated with an increased risk of AD.
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Rai V. Folate Pathway Gene Methylenetetrahydrofolate Reductase C677T Polymorphism and Alzheimer Disease Risk in Asian Population. Indian J Clin Biochem 2015; 31:245-52. [PMID: 27382194 DOI: 10.1007/s12291-015-0512-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 05/30/2015] [Indexed: 10/23/2022]
Abstract
The association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and susceptibility to Alzheimers disease (AD) was controversial in previous studies. The present meta-analysis was designed to investigate the association of MTHFR C677T polymorphism with AD. Nine studies were identified by search of PubMed, Google Scholar, Elsevier, Springer Link databases, up to January 2013. Odds ratios (ORs) with corresponding 95 % confidence interval (CI) were calculated using fixed effects model or random effects model. All statistical analysis was done by Mix version 1.7. MTHFR C677T polymorphism had a significant association with susceptibility to AD in all genetic models (for T vs C: OR 1.29, 95 % CI 1.15-1.44, p < 0.0001; for TT + CT vs CC: OR 1.38, 95 % CI 1.16-1.364, p = 0.0002; for TT vs CC: OR 1.60, 95 % CI 1.25-2.04, p = 0.0001; for CT vs CC: OR 1.28, 95 % CI 1.1-1.53, p < 0.008; for TT vs CT + CC: OR 1.37, 95 % CI 1.12-1.67, p = 0.002). Results from present meta-analysis supported that the MTHFR C677T polymorphism was associated with an increased risk of AD in Asian population.
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Affiliation(s)
- Vandana Rai
- Human Molecular Genetics Laboratory, Department of Biotechnology, VBS Purvanchal University, Jaunpur, 222003 UP India
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The MTHFR C677T polymorphism contributes to increased risk of Alzheimer's disease: evidence based on 40 case-control studies. Neurosci Lett 2014; 586:36-42. [PMID: 25486592 DOI: 10.1016/j.neulet.2014.11.049] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 11/06/2014] [Accepted: 11/28/2014] [Indexed: 11/20/2022]
Abstract
The association between methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and Alzheimer's Disease (AD) risk has been widely reported with inconsistent results. We performed an updated meta-analysis of all available studies to clarify this situation. We conducted a comprehensive literature search in PubMed Alzgene, Embase, and Chinese Biomedical Literature database (CBM) for the period up to June 2014. Finally, a total of 40 case-control studies with 4503 AD cases and 5767 controls were included. Overall, significant increased AD risk was found, when all studies were pooled into the meta-analysis. In subgroup analyses stratified by ethnicity, age of onset, and APOE ϵ4 status, significant increased AD risk was found in Asians, late-onset AD, and APOE ϵ4 carriers, but not in Caucasians, early-onset AD, and non-APOE ϵ4 carriers. The present meta-analysis suggested that the MTHFR is a candidate gene for AD susceptibility. The MTHFR C677T polymorphism may be a risk factor for AD in Asians, APOE ϵ4 carriers, and late-onset AD. Further, investigations taking the potential gene-gene and gene-environmental interactions into consideration for the MTHFR C677T polymorphism should be conducted.
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Belcavello L, Camporez D, Almeida LD, Morelato RL, Batitucci MCP, de Paula F. Association of MTHFR and PICALM polymorphisms with Alzheimer's disease. Mol Biol Rep 2014; 42:611-6. [PMID: 25359311 DOI: 10.1007/s11033-014-3806-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 10/27/2014] [Indexed: 01/17/2023]
Abstract
Alzheimer's disease (AD) is a complex neurodegenerative disorder and the primary cause of dementia in the elderly and causes a decrease in cognition, functionality, and behaviour. Genetic risk factors play an important role in the pathogenesis of AD. In this case-control study, we aimed to investigate whether single nucleotide polymorphisms in MTHFR (rs1801133), PICALM (3851719), CLU (rs11136000), and CR1 (rs6701713) are associated with AD. Genotype frequencies were evaluated in 82 late-onset AD patients and 161 elderly healthy controls matched by age and gender. We detected a significant association of the MTHFR rs1801133 and PICALM rs3851179 polymorphisms with AD. The results of this study support the hypothesis that several genes are involved in the aetiology of AD.
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Affiliation(s)
- Luciano Belcavello
- Department of Biological Sciences, Human Molecular Genetics Center, Federal University of Espírito Santo, Vitória, ES, Brazil,
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Roussotte FF, Daianu M, Jahanshad N, Leonardo CD, Thompson PM. Neuroimaging and genetic risk for Alzheimer's disease and addiction-related degenerative brain disorders. Brain Imaging Behav 2014; 8:217-233. [PMID: 24142306 PMCID: PMC3992278 DOI: 10.1007/s11682-013-9263-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Neuroimaging offers a powerful means to assess the trajectory of brain degeneration in a variety of disorders, including Alzheimer's disease (AD). Here we describe how multi-modal imaging can be used to study the changing brain during the different stages of AD. We integrate findings from a range of studies using magnetic resonance imaging (MRI), positron emission tomography (PET), functional MRI (fMRI) and diffusion weighted imaging (DWI). Neuroimaging reveals how risk genes for degenerative disorders affect the brain, including several recently discovered genetic variants that may disrupt brain connectivity. We review some recent neuroimaging studies of genetic polymorphisms associated with increased risk for late-onset Alzheimer's disease (LOAD). Some genetic variants that increase risk for drug addiction may overlap with those associated with degenerative brain disorders. These common associations offer new insight into mechanisms underlying neurodegeneration and addictive behaviors, and may offer new leads for treating them before severe and irreversible neurological symptoms appear.
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Affiliation(s)
- Florence F Roussotte
- Imaging Genetics Center, Laboratory of Neuro Imaging, Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Madelaine Daianu
- Imaging Genetics Center, Laboratory of Neuro Imaging, Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Neda Jahanshad
- Imaging Genetics Center, Laboratory of Neuro Imaging, Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Cassandra D Leonardo
- Imaging Genetics Center, Laboratory of Neuro Imaging, Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Paul M Thompson
- Imaging Genetics Center, Laboratory of Neuro Imaging, Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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The MTHFR 677T allele may influence the severity and biochemical risk factors of Alzheimer's disease in an Egyptian population. DISEASE MARKERS 2013. [PMID: 24223459 DOI: 10.1155/2013/524106]] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE We evaluated whether the methylenetetrahydrofolate reductase (MTHFR) 677C>T marker influences the risk and severity of Alzheimer's disease (AD) and whether AD is associated with homocysteine, vitamin B12, and cholesterol levels in Egypt. METHODS Forty-three Alzheimer's cases and 32 non-AD controls were genotyped for the 677C>T polymorphism. Clinical characteristics and levels of homocysteine, vitamin B12, and cholesterol were assessed. RESULTS No significant differences in the frequencies of the MTHFR alleles or genotypes between AD cases and controls (P = 0.14) were identified. The 677T mutant allele was significantly overrepresented in AD cases compared to controls (OR = 2.22; P = 0.03). The 677T/T frequency was three times higher in AD patients than in controls, which could increase plasma homocysteine levels. Severe cases of AD were the most frequent in patients with the T/T genotype (11.6%). The effect of the MTHFR polymorphism on the risk of AD may be independent of homocysteine, vitamin B12, or even cholesterol levels. CONCLUSIONS The MTHFR 677C>T polymorphism--especially the presence of one copy of the T allele--appears to confer a potential risk for the development of AD. The T/T genotype may contribute to hypercysteinemia as a sensitive marker.
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Association of COMT, MTHFR, and SLC19A1(RFC-1) polymorphisms with homocysteine blood levels and cognitive impairment in Parkinson's disease. Pharmacogenet Genomics 2013; 22:716-24. [PMID: 22890010 DOI: 10.1097/fpc.0b013e32835693f7] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Elevated plasma homocysteine (Hcy) concentration is an independent risk factor for cardiovascular disease, and its involvement in endothelial cell dysfunction is well established. However, the role of Hcy and folate in the pathogenesis of Parkinson's disease (PD) remains controversial. OBJECTIVES The study was aimed at evaluating the relationships between Hcy, vitamin B12, and folic acid levels in the blood and cognitive status in PD patients with the genetic polymorphisms of MTHFR (rs1801133: C>T-677C>T, rs1801131: A>C-1298A>C), COMT (rs4680: A>G-Val158Met, rs6269: A>G, rs4633: C>T, rs4818: C>G), or SLC19A1 (rs1051266: G>A-80G>A). METHODS A total of 502 participants (248 with PD and 254 age-matched and sex-matched controls) were included in the study. The Unified Parkinson's Disease Rating Scale score, Hoehn-Yahr staging, and the Schwab-England scale were used to assess motor abilities and activity during daily life. Complex psychological examination with a battery of tests was used to classify patients into groups with (PDD) and without (nPDD) dementia. Blood samples were examined for Hcy, vitamin B12, and folic acid levels, as well as polymorphisms in genes related to Hcy metabolism, such as COMT, MTHFR, and SLC19A1(RFC-1). RESULTS The frequency of homozygous COMT rs4680G and rs4633C allele carriers was significantly decreased in PD patients in comparison with the controls (P=0.015; odds ratio=0.60; 95% confidence interval 0.41-0.90 and P=0.020; odds ratio=0.619; 95% confidence interval 0.42-0.92, respectively). No significant differences in the distribution of MTHFR 677C>T, 1298A>C, and SLC19A1 80G>A alleles and genotypes between PD patients and the controls were found. Hcy levels were significantly increased in PD patients (18±7.8 μmol/l) as compared with the controls (14.0±9.6 μmol/l, P=10(-8)) and were significantly associated with the MTHFR 677C>T polymorphism both in PD patients and controls, in which T allele carriers were characterized by markedly elevated Hcy plasma concentrations. No association was observed between Hcy plasma level and COMT and SLC19A polymorphisms. The results of multivariate logistic regression analysis revealed age (P=0.0003) and Hcy plasma levels (P=0.07) as independent risk factors predisposing individuals to PD dementia. The studied polymorphisms were not associated with cognitive status in PD patients. CONCLUSION The genetic factors studied were not associated with cognitive status in PD patients. Only age and Hcy plasma levels were found to be independent risk factors predisposing individuals to PD dementia. However, COMT: rs4680: A>G and rs4633: C>T polymorphisms were found to significantly affect PD risk, and the MTHFR 677C>T polymorphism helped determine plasma Hcy concentrations.
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Elhawary NA, Hewedi D, Arab A, Teama S, Shaibah H, Tayeb MT, Bogari N. The MTHFR 677T allele may influence the severity and biochemical risk factors of Alzheimer's disease in an Egyptian population. DISEASE MARKERS 2013; 35:439-46. [PMID: 24223459 PMCID: PMC3810363 DOI: 10.1155/2013/524106] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/18/2013] [Accepted: 09/20/2013] [Indexed: 02/08/2023]
Abstract
OBJECTIVE We evaluated whether the methylenetetrahydrofolate reductase (MTHFR) 677C>T marker influences the risk and severity of Alzheimer's disease (AD) and whether AD is associated with homocysteine, vitamin B12, and cholesterol levels in Egypt. METHODS Forty-three Alzheimer's cases and 32 non-AD controls were genotyped for the 677C>T polymorphism. Clinical characteristics and levels of homocysteine, vitamin B12, and cholesterol were assessed. RESULTS No significant differences in the frequencies of the MTHFR alleles or genotypes between AD cases and controls (P = 0.14) were identified. The 677T mutant allele was significantly overrepresented in AD cases compared to controls (OR = 2.22; P = 0.03). The 677T/T frequency was three times higher in AD patients than in controls, which could increase plasma homocysteine levels. Severe cases of AD were the most frequent in patients with the T/T genotype (11.6%). The effect of the MTHFR polymorphism on the risk of AD may be independent of homocysteine, vitamin B12, or even cholesterol levels. CONCLUSIONS The MTHFR 677C>T polymorphism--especially the presence of one copy of the T allele--appears to confer a potential risk for the development of AD. The T/T genotype may contribute to hypercysteinemia as a sensitive marker.
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Affiliation(s)
- Nasser Attia Elhawary
- 1Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, P.O. Box 57543, Makkah 21955, Saudi Arabia
- 2Department of Molecular Genetics, Medical Genetics Center, Faculty of Medicine, Ain Shams University, Cairo 11566, Egypt
- *Nasser Attia Elhawary:
| | - Doaa Hewedi
- 3Department of Psychiatry, Faculty of Medicine, Ain Shams University, Cairo 11566, Egypt
| | - Arwa Arab
- 4Department of Psychology, Faculty of Arts and Humanities, King Abdulaziz University, P.O. Box 80200, Jeddah 21589, Saudi Arabia
| | - Salwa Teama
- 5Department of Clinical Pathology, Medical Research Center, Faculty of Medicine, Ain Shams University, P.O. Box 80200, Cairo 11566, Egypt
| | - Hassan Shaibah
- 6Department of Anatomy, Faculty of Medicine, Umm Al-Qura University, P.O. Box 7607, Makkah 21955, Saudi Arabia
| | - Mohammed Taher Tayeb
- 1Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, P.O. Box 57543, Makkah 21955, Saudi Arabia
| | - Neda Bogari
- 1Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, P.O. Box 57543, Makkah 21955, Saudi Arabia
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Wang H, Liu C. Association of MTHFR C667T polymorphism with bone mineral density and fracture risk: an updated meta-analysis. Osteoporos Int 2012; 23:2625-34. [PMID: 22187009 DOI: 10.1007/s00198-011-1885-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 12/08/2011] [Indexed: 11/26/2022]
Abstract
UNLABELLED This meta-analysis investigated the association of C677T polymorphism in MTHFR gene with bone mineral density (BMD) and fracture risk. The results suggested that C677T polymorphism was marginally associated with fracture risk. In addition, this polymorphism was modestly associated with BMD of lumbar spine, femoral neck, total hip, and total body, respectively. INTRODUCTION The methylenetetrahydrofolate reductase (MTHFR) gene has been implicated in the regulation of BMD and, thus, may serve as a potential risk factor for the development of fracture. However, results have been inconsistent. In this study, a meta-analysis was performed to clarify the association of C677T polymorphism in MTHFR gene with BMD and fracture risk. METHODS Published literature from PubMed and EMBASE were searched for eligible publications. Pooled odds ratio (OR) or weighted mean difference (WMD) and 95% confidence interval (CI) were calculated using a fixed- or random-effects model. RESULTS Twenty studies (3,525 cases and 17,909 controls) were included in this meta-analysis. The TT genotype of C677T polymorphism was marginally associated with an increased risk of fracture under recessive model (TT vs. TC + CC: OR = 1.23, 95% CI 1.04-1.47). Using this model, similar results were found among East Asians (OR = 1.40, 95% CI 1.07-1.83), female subpopulation (1.27, 95% CI 1.04-1.55), cohort studies (OR = 1.24, 95% CI 1.08-1.44), and subjects younger than aged 60 years (OR = 1.51, 95% CI 1.10-2.07). In addition, under homogeneous co-dominant model, there was a modest association of C677T polymorphism with BMD of lumbar spine (WMD = -0.017 g/cm(2); 95%CI, -0.030-(-0.005) g/cm(2)), femoral neck (WMD = -0.010 g/cm(2); 95% CI -0.017-(-0.003) g/cm(2)), total hip (WMD = -0.013 g/cm(2), 95% CI -0.022-(-0.004) g/cm(2)), and total body (WMD = -0.020 g/cm(2); 95% CI -0.027-(-0.013) g/cm(2)), respectively. CONCLUSIONS This meta-analysis suggested that C677T polymorphism was marginally associated with fracture risk. In addition, this polymorphism was modestly associated with BMD of lumbar spine, femoral neck, total hip, and total body, respectively.
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Affiliation(s)
- H Wang
- Department of Orthopedics, Taizhou Municipal Hospital, Taizhou, 318000, China
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Kotze MJ, van Rensburg SJ. Pathology supported genetic testing and treatment of cardiovascular disease in middle age for prevention of Alzheimer's disease. Metab Brain Dis 2012; 27:255-66. [PMID: 22552896 PMCID: PMC3429783 DOI: 10.1007/s11011-012-9296-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 03/15/2012] [Indexed: 11/30/2022]
Abstract
Chronic, multi-factorial conditions caused by a complex interaction between genetic and environmental risk factors frequently share common disease mechanisms, as evidenced by an overlap between genetic risk factors for cardiovascular disease (CVD) and Alzheimer's disease (AD). Single nucleotide polymorphisms (SNPs) in several genes including ApoE, MTHFR, HFE and FTO are known to increase the risk of both conditions. The E4 allele of the ApoE polymorphism is the most extensively studied risk factor for AD and increases the risk of coronary heart disease by approximately 40%. It furthermore displays differential therapeutic responses with use of cholesterol-lowering statins and acetylcholinesterase inhibitors, which may also be due to variation in the CYP2D6 gene in some patients. Disease expression may be triggered by gene-environment interaction causing conversion of minor metabolic abnormalities into major brain disease due to cumulative risk. A growing body of evidence supports the assessment and treatment of CVD risk factors in midlife as a preventable cause of cognitive decline, morbidity and mortality in old age. In this review, the concept of pathology supported genetic testing (PSGT) for CVD is described in this context. PSGT combines DNA testing with biochemical measurements to determine gene expression and to monitor response to treatment. The aim is to diagnose treatable disease subtypes of complex disorders, facilitate prevention of cumulative risk and formulate intervention strategies guided from the genetic background. CVD provides a model to address the lifestyle link in most chronic diseases with a genetic component. Similar preventative measures would apply for optimisation of heart and brain health.
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Affiliation(s)
- Maritha J. Kotze
- Division of Anatomical Pathology, Faculty of Health Sciences, University of Stellenbosch, PO Box 19063 Tygerberg, 7505, South Africa
| | - Susan J. van Rensburg
- Division of Chemical Pathology, National Health Laboratory Service and University of Stellenbosch, Tygerberg Hospital, PO Box 19113 Tygerberg 7505, South Africa
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Coppedè F, Tannorella P, Pezzini I, Migheli F, Ricci G, Caldarazzo lenco E, Piaceri I, Polini A, Nacmias B, Monzani F, Sorbi S, Siciliano G, Migliore L. Folate, homocysteine, vitamin B12, and polymorphisms of genes participating in one-carbon metabolism in late-onset Alzheimer's disease patients and healthy controls. Antioxid Redox Signal 2012; 17:195-204. [PMID: 22034983 DOI: 10.1089/ars.2011.4368] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
AIMS We screened 378 late-onset Alzheimer's disease (LOAD) patients and 308 matched controls for the presence of the common MTHFR 677C>T, MTRR 66A>G, MTR 2756 A>G, and TYMS 28 bp repeat polymorphisms, searching for association with disease risk and age at onset. Moreover, we searched for correlation between each of the studied polymorphisms and available data on plasma homocysteine (Hcy), serum folate, and vitamin B12 values. RESULTS We observed a significant increased frequency of the MTHFR 677T allele (0.48 vs. 0.42; p=0.019) and of MTHFR 677CT (OR=1.46; 95%CI=1.03-2.06) and TT genotypes (OR=1.62; 95%CI=1.05-2.49) in LOAD subjects with respect to controls. We also observed a significant increased frequency of the MTRR 66G allele (0.49 vs. 0.43; p=0.044) and of the MTRR 66GG genotype (OR=1.57; 95%CI=1.01-2.46) in the LOAD group. Significantly increased mean plasma Hcy levels (22.7±1.7 vs 14.5±1.7 μmol/L; p=0.037) and decreased serum folate values (5.7±0.5 vs. 7.8±0.8 ng/mL; p=0.005) were observed in LOAD subjects with respect to controls, whilst the difference in serum vitamin B12 values did not reach statistical significance. Several interactions between the studied polymorphisms and biochemical biomarkers were observed. None of the studied polymorphisms was associated with disease age at onset. INNOVATION The present study suggests that the MTRR 66G allele might contribute to LOAD risk and confirms an increased frequency of the MTHFR 677T allele in LOAD. CONCLUSION Overall, present results support a contribution for one-carbon metabolism to LOAD pathogenesis.
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Affiliation(s)
- Fabio Coppedè
- Faculty of Medicine, University of Pisa, Pisa, Italy.
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Mansoori N, Tripathi M, Luthra K, Alam R, Lakshmy R, Sharma S, Arulselvi S, Parveen S, Mukhopadhyay AK. MTHFR (677 and 1298) and IL-6-174 G/C genes in pathogenesis of Alzheimer's and vascular dementia and their epistatic interaction. Neurobiol Aging 2011; 33:1003.e1-8. [PMID: 22015309 DOI: 10.1016/j.neurobiolaging.2011.09.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Revised: 07/26/2011] [Accepted: 09/10/2011] [Indexed: 11/17/2022]
Abstract
Genetic risk factors play an important role in the pathogenesis of Alzheimer disease (AD) and vascular dementia (VaD). In this case-control study, we examined C677T and A1298C (rs1801133 and rs1801131) polymorphism in the methylenetetrahydrofolate reductase (MTHFR) genes and their correlation with plasma levels of homocysteine (Hcy) in AD and VaD cases and evaluated the gene-gene interaction (epistasis) with IL-6-174 G/C (rs1800795). CC genotype was associated with elevated levels of plasma homocysteine (p = 0.004) as compared with genotype AA of rs1801131. In AD, we observed a significant (p = 0.04) association with C alleles of rs1801131. Regression analysis revealed that the presence of both rs1801133 T and rs1800795 C alleles increased the odds of developing AD by 2.5 and VaD by 3.7-fold. While rs1800795 (CC or GC) genotypes alone increased the odds of developing VaD by 2.2-fold, the presence of CC genotype of rs1801131 nullified this effect. The findings support the hypothesis that multiple genes are involved to alter the odds of developing AD and VaD.
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Affiliation(s)
- Nasim Mansoori
- Department of Laboratory Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
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