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Kusters CDJ, Paul KC, Romero T, Sinsheimer JS, Ritz BR. Among men, androgens are associated with a decrease in Alzheimer's disease risk. Alzheimers Dement 2023; 19:3826-3834. [PMID: 36938850 PMCID: PMC10509321 DOI: 10.1002/alz.13013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 03/21/2023]
Abstract
INTRODUCTION Increased levels of sex hormones have been hypothesized to decrease Alzheimer's disease (AD) risk. We assessed the association between sex steroid hormones with AD using a Mendelian randomization (MR) approach. METHODS An inverse-variance weighting (IVW) MR analysis was performed using effect estimates from external genome-wide association study (GWAS) summary statistics. We included independent variants (linkage disequilibrium R2 < 0.001) and a p-value threshold of 5 × 10-8 . RESULTS An increase in androgens was associated with a decreased AD risk among men: testosterone (odds ratio [OR]: 0.53; 95% confidence interval [CI]: 0.32-0.88; p-value: 0.01; false discovery rate [FDR] p-value: 0.03); dehydroepiandrosterone sulfate (DHEAS; OR: 0.56; 95% CI: 0.38-0.85; p-value: 0.01; FDR p-value: 0.03); and androsterone sulfate (OR: 0.69; 95% CI: 0.46-1.02; p-value: 0.06; FDR p-value: 0.10). There was no association between sex steroid hormones and AD among women, although analysis for estradiol had limited statistical power. DISCUSSION A higher concentration of androgens was associated with a decreased risk of AD among men of European ancestry, suggesting that androgens among men might be neuroprotective and could potentially prevent or delay an AD diagnosis. HIGHLIGHTS Sex hormones are hypothesized to play a role in developing Alzheimer's disease (AD). The effect of sex hormones on AD was assessed using Mendelian randomization (MR) analysis. Among women, genetically determined effects of sex hormones were limited or null. Among men, a higher concentration of androgens decreased AD risk. This study suggests a causal relationship between androgens and AD among men.
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Affiliation(s)
- Cynthia D J Kusters
- Department of Human Genetics, David Geffen School of Medicine, Los Angeles, California, USA
| | - Kimberly C Paul
- Department of Neurology, David Geffen School of Medicine, Los Angeles, California, USA
| | - Tahmineh Romero
- Statistics Core, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Janet S Sinsheimer
- Department of Human Genetics, David Geffen School of Medicine, Los Angeles, California, USA
- Department of Biostatistics, School of Public Health, University of California, Los Angeles, California, USA
- Department of Computational Medicine, David Geffen School of Medicine, Los Angeles, California, USA
| | - Beate R Ritz
- Department of Neurology, David Geffen School of Medicine, Los Angeles, California, USA
- Department of Epidemiology, UCLA Fielding School of Public Health, Los Angeles, California, USA
- Department of Environmental Health, UCLA Fielding School of Public Health, Los Angeles, California, USA
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2
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Giannos P, Prokopidis K, Church DD, Kirk B, Morgan PT, Lochlainn MN, Macpherson H, Woods DR, Ispoglou T. Associations of Bioavailable Serum Testosterone With Cognitive Function in Older Men: Results From the National Health and Nutrition Examination Survey. J Gerontol A Biol Sci Med Sci 2023; 78:151-157. [PMID: 35927217 PMCID: PMC9879757 DOI: 10.1093/gerona/glac162] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Age-associated cognitive decline may be influenced by testosterone status. However, studies evaluating the impact of bioavailable testosterone, the active, free testosterone, on cognitive function are scarce. Our study determined the relationship between calculated bioavailable testosterone and cognitive performance in older men. METHODS We used data from the U.S. National Health and Nutrition Examination Survey (NHANES) between 2013 and 2014. This study consisted of 208 men aged ≥60 years. Bioavailable serum testosterone was calculated based on the total serum testosterone, sex hormone-binding globulin, and albumin levels, whereas cognitive performance was assessed through the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test (WLLT), Word List Recall Test (WLRT), and Intrusion Word Count Test (WLLT-IC and WLRT-IC), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). Multiple linear regression analyses were performed upon adjustment for age, ethnicity, socioeconomic status, education level, medical history, body mass index, energy, alcohol intake, physical activity levels, and sleep duration. RESULTS A significant positive association between bioavailable testosterone and DSST (β: 0.049, p = .002) score was detected, with no signs of a plateau effect. No significant associations with CERAD WLLT (p = .132), WLRT (p = .643), WLLT-IC (p = .979), and WLRT-IC (p = .387), and AFT (p = .057) were observed. CONCLUSION Calculated bioavailable testosterone presented a significant positive association with processing speed, sustained attention, and working memory in older men above 60 years of age. Further research is warranted to elucidate the impact of the inevitable age-related decline in testosterone on cognitive function in older men.
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Affiliation(s)
- Panagiotis Giannos
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK.,Society of Meta-research and Biomedical Innovation, London, UK
| | - Konstantinos Prokopidis
- Society of Meta-research and Biomedical Innovation, London, UK.,Department of Musculoskeletal Biology, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - David D Church
- Department of Geriatrics, Donald W. Reynolds Institute on Aging, Center for Translational Research in Aging and Longevity, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Ben Kirk
- Department of Medicine-Western Health, Melbourne Medical School, University of Melbourne, Melbourne, Victoria, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St. Albans, Melbourne, Victoria, Australia
| | - Paul T Morgan
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK.,Department of Sport and Exercise Sciences, Manchester Metropolitan University, Manchester, UK
| | - Mary Ni Lochlainn
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - Helen Macpherson
- Deakin University, Geelong, Victoria, Australia.,Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Burwood, Victoria, Australia
| | - David R Woods
- Defence Medical Services, Lichfield, UK.,Carnegie School of Sport, Leeds Beckett University, Leeds, UK
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3
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Genetic Variation and Mendelian Randomization Approaches. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1390:327-342. [DOI: 10.1007/978-3-031-11836-4_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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4
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Dong X, Jiang H, Li S, Zhang D. Low Serum Testosterone Concentrations Are Associated With Poor Cognitive Performance in Older Men but Not Women. Front Aging Neurosci 2021; 13:712237. [PMID: 34790110 PMCID: PMC8591394 DOI: 10.3389/fnagi.2021.712237] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 10/13/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: Current evidence on the association between serum testosterone and cognitive performance has been inconsistent, especially in older adults. To investigate the associations between serum testosterone and cognitive performance in a nationally representative sample of older men and women. Methods: We used data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. 1,303 men and 1,349 women aged 60 years or older were included in the study. Serum total testosterone was preformed via isotope dilution liquid chromatography tandem mass spectrometry (ID-LC-MS/MS) method. Free testosterone was calculated by Vermeulen's formula. Cognitive performance was evaluated by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) test, Animal Fluency test, and Digit Symbol Substitution Test (DSST). Binary logistic regression and restricted cubic spline models were applied to evaluate the association of testosterone and cognitive performance. Results: In men, higher concentrations of total testosterone were associated with better performance on CERAD test (OR = 0.51; 95%CI = 0.27-0.95) and DSST (OR = 0.54; 95%CI = 0.30-0.99) in adjusted group. Similarly, higher concentrations of free testosterone were associated with better performance on CERAD test (OR = 0.32; 95%CI = 0.17-0.61) and DSST (OR = 0.41; 95%CI = 0.17-0.96) in men. These associations were not seen in women. Conclusion: Serum testosterone concentrations were inversely associated with cognitive performance in older men but not women in the United States.
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Affiliation(s)
- Xue Dong
- Department of Epidemiology and Health Statistics, The School of Public Health, Qingdao University, Qingdao, China
| | - Hong Jiang
- Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Suyun Li
- Department of Epidemiology and Health Statistics, The School of Public Health, Qingdao University, Qingdao, China
| | - Dongfeng Zhang
- Department of Epidemiology and Health Statistics, The School of Public Health, Qingdao University, Qingdao, China
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5
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Flynn E, Tanigawa Y, Rodriguez F, Altman RB, Sinnott-Armstrong N, Rivas MA. Sex-specific genetic effects across biomarkers. Eur J Hum Genet 2020; 29:154-163. [PMID: 32873964 DOI: 10.1038/s41431-020-00712-w] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/28/2020] [Accepted: 08/04/2020] [Indexed: 11/09/2022] Open
Abstract
Sex differences have been shown in laboratory biomarkers; however, the extent to which this is due to genetics is unknown. In this study, we infer sex-specific genetic parameters (heritability and genetic correlation) across 33 quantitative biomarker traits in 181,064 females and 156,135 males from the UK Biobank study. We apply a Bayesian Mixture Model, Sex Effects Mixture Model (SEMM), to Genome-wide Association Study summary statistics in order to (1) estimate the contributions of sex to the genetic variance of these biomarkers and (2) identify variants whose statistical association with these traits is sex-specific. We find that the genetics of most biomarker traits are shared between males and females, with the notable exception of testosterone, where we identify 119 female and 445 male-specific variants. These include protein-altering variants in steroid hormone production genes (POR, UGT2B7). Using the sex-specific variants as genetic instruments for Mendelian randomization, we find evidence for causal links between testosterone levels and height, body mass index, waist and hip circumference, and type 2 diabetes. We also show that sex-specific polygenic risk score models for testosterone outperform a combined model. Overall, these results demonstrate that while sex has a limited role in the genetics of most biomarker traits, sex plays an important role in testosterone genetics.
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Affiliation(s)
- Emily Flynn
- Biomedical Informatics Training Program, Stanford University, Stanford, CA, USA.
| | - Yosuke Tanigawa
- Biomedical Informatics Training Program, Stanford University, Stanford, CA, USA
| | - Fatima Rodriguez
- Department of Medicine, Division of Cardiovascular Medicine and the Cardiovascular Institute, Stanford University, Stanford, CA, USA
| | - Russ B Altman
- Biomedical Informatics Training Program, Stanford University, Stanford, CA, USA.,Department of Medicine, Stanford University, Stanford, CA, USA.,Department of Bioengineering, Stanford University, Stanford, CA, USA.,Department of Genetics, Stanford University, Stanford, CA, USA
| | | | - Manuel A Rivas
- Biomedical Informatics Training Program, Stanford University, Stanford, CA, USA.
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6
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Syed AAS, He L, Shi Y. The Potential Effect of Aberrant Testosterone Levels on Common Diseases: A Mendelian Randomization Study. Genes (Basel) 2020; 11:E721. [PMID: 32610558 PMCID: PMC7397292 DOI: 10.3390/genes11070721] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/21/2020] [Accepted: 06/26/2020] [Indexed: 12/22/2022] Open
Abstract
Testosterone has historically been linked to sexual dysfunction; however, it has recently been shown to affect other physical and mental attributes. We attempted to determine whether changes in serum testosterone could play a role in chronic or degenerative diseases. We used two separate genetic instruments comprising of variants from JMJD1C and SHBG regions and conducted a two-sample Mendelian randomization for type II diabetes (T2D), gout, rheumatoid arthritis (RA), schizophrenia, bipolar disorder, Alzheimer's disease and depression. For the JMJD1C locus, one unit increase in log transformed testosterone was significantly associated with RA (OR = 1.69, p = 0.02), gout (OR = 0.469, p = 0.001) and T2D (OR = 0.769, p = 0.048). Similarly, one unit increase in log transformed testosterone using variants from the SHBG locus was associated with depression (OR = 1.02, p < 0.0001), RA (OR = 1.254, p < 0.0001) and T2D (OR = 0.88, p < 0.0001). Our results show that low levels of serum testosterone levels may cause gout and T2D, while higher than normal levels of testosterone may result in RA and depression. Our findings suggest that fluctuations in testosterone levels may have severe consequences that warrant further investigation.
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Affiliation(s)
- Ali Alamdar Shah Syed
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030, China; (L.H.); (Y.S.)
| | - Lin He
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030, China; (L.H.); (Y.S.)
- Shanghai Center for Women and Children’s Health, 339 Luding Road, Shanghai 200062, China
| | - Yongyong Shi
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030, China; (L.H.); (Y.S.)
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7
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Kuźma E, Hannon E, Zhou A, Lourida I, Bethel A, Levine DA, Lunnon K, Thompson-Coon J, Hyppönen E, Llewellyn DJ. Which Risk Factors Causally Influence Dementia? A Systematic Review of Mendelian Randomization Studies. J Alzheimers Dis 2019; 64:181-193. [PMID: 29865062 PMCID: PMC6004893 DOI: 10.3233/jad-180013] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background: Numerous risk factors for dementia are well established, though the causal nature of these associations remains unclear. Objective: To systematically review Mendelian randomization (MR) studies investigating causal relationships between risk factors and global cognitive function or dementia. Methods: We searched five databases from inception to February 2017 and conducted citation searches including MR studies investigating the association between any risk factor and global cognitive function, all-cause dementia or dementia subtypes. Two reviewers independently assessed titles and abstracts, full-texts, and study quality. Results: We included 18 MR studies investigating education, lifestyle factors, cardiovascular factors and related biomarkers, diabetes related and other endocrine factors, and telomere length. Studies were of predominantly good quality, however eight received low ratings for sample size and statistical power. The most convincing causal evidence was found for an association of shorter telomeres with increased risk of Alzheimer’s disease (AD). Causal evidence was weaker for smoking quantity, vitamin D, homocysteine, systolic blood pressure, fasting glucose, insulin sensitivity, and high-density lipoprotein cholesterol. Well-replicated associations were not present for most exposures and we cannot fully discount survival and diagnostic bias, or the potential for pleiotropic effects. Conclusions: Genetic evidence supported a causal association between telomere length and AD, whereas limited evidence for other risk factors was largely inconclusive with tentative evidence for smoking quantity, vitamin D, homocysteine, and selected metabolic markers. The lack of stronger evidence for other risk factors may reflect insufficient statistical power. Larger well-designed MR studies would therefore help establish the causal status of these dementia risk factors.
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Affiliation(s)
| | | | - Ang Zhou
- Centre for Population Health Research, University of South Australia, Adelaide, Australia
| | | | - Alison Bethel
- NIHR CLAHRC South West Peninsula (PenCLAHRC), University of Exeter Medical School, Exeter, UK
| | - Deborah A Levine
- University of Michigan and Veterans Affairs Center for Clinical Management Research, Ann Arbor, USA
| | | | - Jo Thompson-Coon
- NIHR CLAHRC South West Peninsula (PenCLAHRC), University of Exeter Medical School, Exeter, UK
| | - Elina Hyppönen
- Centre for Population Health Research, University of South Australia, Adelaide, Australia
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8
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Yeap BB, Page ST, Grossmann M. Testosterone treatment in older men: clinical implications and unresolved questions from the Testosterone Trials. Lancet Diabetes Endocrinol 2018; 6:659-672. [PMID: 30017800 DOI: 10.1016/s2213-8587(17)30416-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/02/2017] [Accepted: 11/06/2017] [Indexed: 10/28/2022]
Abstract
A decrease in the concentration of circulating testosterone in many older men is a biomarker and possibly a rectifiable contributing factor to ill health. Low circulating testosterone concentration has been associated with cardiovascular disease, reduced cognition, fracture risk, and anaemia. However, randomised placebo-controlled trials are essential to clarify the benefits and possible risks of testosterone treatment in men without hypothalamic, pituitary, or testicular disease. The Testosterone Trials (T-Trials) were a coordinated set of trials that, following a screening-to-enrolment ratio of 65:1, randomly assigned 790 men aged 65 years or older who had a baseline testosterone concentration of less than 9·54 nmol/L and symptoms consistent with hypogonadism, but no recognisable hypothalamic-pituitary-testicular axis pathology, to daily transdermal testosterone or placebo for 12 months. In the main trial, testosterone treatment resulted in a modest benefit for sexual function, whereas the other primary outcomes of vitality and physical function were not met. Data from concomitant substudies raised a possible concern over changes in coronary plaque volume, showed a neutral effect on memory and other cognitive functions, and revealed improvements in volumetric bone mineral density and anaemia. Although insufficient to alter the existing clinical equipoise, the T-Trials provided substantial new data on organ-specific outcomes for testosterone treatment in older men. Further clinical trials are necessary to determine whether testosterone treatment will translate into patient-valued health outcomes and to clarify effects on the cardiovascular system.
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Affiliation(s)
- Bu B Yeap
- School of Medicine, University of Western Australia, Perth, WA, Australia; Department of Endocrinology and Diabetes, Fiona Stanley Hospital, Perth, WA, Australia
| | - Stephanie T Page
- Division of Metabolism and Endocrinology, University of Washington, Seattle, WA, USA.
| | - Mathis Grossmann
- Department of Medicine, University of Melbourne, Melbourne, VIC, Australia; Department of Endocrinology, Austin Health, Melbourne, VIC, Australia
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9
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Mihelčić M, Šimić G, Babić Leko M, Lavrač N, Džeroski S, Šmuc T. Using redescription mining to relate clinical and biological characteristics of cognitively impaired and Alzheimer's disease patients. PLoS One 2017; 12:e0187364. [PMID: 29088293 PMCID: PMC5663625 DOI: 10.1371/journal.pone.0187364] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 10/18/2017] [Indexed: 11/18/2022] Open
Abstract
Based on a set of subjects and a collection of attributes obtained from the Alzheimer's Disease Neuroimaging Initiative database, we used redescription mining to find interpretable rules revealing associations between those determinants that provide insights about the Alzheimer's disease (AD). We extended the CLUS-RM redescription mining algorithm to a constraint-based redescription mining (CBRM) setting, which enables several modes of targeted exploration of specific, user-constrained associations. Redescription mining enabled finding specific constructs of clinical and biological attributes that describe many groups of subjects of different size, homogeneity and levels of cognitive impairment. We confirmed some previously known findings. However, in some instances, as with the attributes: testosterone, ciliary neurotrophic factor, brain natriuretic peptide, Fas ligand, the imaging attribute Spatial Pattern of Abnormalities for Recognition of Early AD, as well as the levels of leptin and angiopoietin-2 in plasma, we corroborated previously debatable findings or provided additional information about these variables and their association with AD pathogenesis. Moreover, applying redescription mining on ADNI data resulted with the discovery of one largely unknown attribute: the Pregnancy-Associated Protein-A (PAPP-A), which we found highly associated with cognitive impairment in AD. Statistically significant correlations (p ≤ 0.01) were found between PAPP-A and clinical tests: Alzheimer's Disease Assessment Scale, Clinical Dementia Rating Sum of Boxes, Mini Mental State Examination, etc. The high importance of this finding lies in the fact that PAPP-A is a metalloproteinase, known to cleave insulin-like growth factor binding proteins. Since it also shares similar substrates with A Disintegrin and the Metalloproteinase family of enzymes that act as α-secretase to physiologically cleave amyloid precursor protein (APP) in the non-amyloidogenic pathway, it could be directly involved in the metabolism of APP very early during the disease course. Therefore, further studies should investigate the role of PAPP-A in the development of AD more thoroughly.
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Affiliation(s)
- Matej Mihelčić
- Division of Electronics, Ruđer Bošković Institute, Zagreb, Croatia
- Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Goran Šimić
- Department for Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| | - Mirjana Babić Leko
- Department for Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| | - Nada Lavrač
- Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
- Department of Knowledge Technologies, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Sašo Džeroski
- Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
- Department of Knowledge Technologies, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Tomislav Šmuc
- Division of Electronics, Ruđer Bošković Institute, Zagreb, Croatia
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10
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Maney DL. Polymorphisms in sex steroid receptors: From gene sequence to behavior. Front Neuroendocrinol 2017; 47:47-65. [PMID: 28705582 PMCID: PMC6312198 DOI: 10.1016/j.yfrne.2017.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/05/2017] [Accepted: 07/08/2017] [Indexed: 01/09/2023]
Abstract
Sex steroid receptors have received much interest as potential mediators of human behaviors and mental disorders. Candidate gene association studies have identified about 50 genetic variants of androgen and estrogen receptors that correlate with human behavioral phenotypes. Because most of these polymorphisms lie outside coding regions, discerning their effect on receptor function is not straightforward. Thus, although discoveries of associations improve our ability to predict risk, they have not greatly advanced our understanding of underlying mechanisms. This article is intended to serve as a starting point for psychologists and other behavioral biologists to consider potential mechanisms. Here, I review associations between polymorphisms in sex steroid receptors and human behavioral phenotypes. I then consider ways in which genetic variation can affect processes such as mRNA transcription, splicing, and stability. Finally, I suggest ways that hypotheses about mechanism can be tested, for example using in vitro assays and/or animal models.
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Affiliation(s)
- Donna L Maney
- Department of Psychology, 36 Eagle Row, Emory University, Atlanta, GA 30322, USA.
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11
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Fisch GS. Whither the genotype-phenotype relationship? An historical and methodological appraisal. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2017; 175:343-353. [DOI: 10.1002/ajmg.c.31571] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/21/2017] [Accepted: 06/28/2017] [Indexed: 01/25/2023]
Affiliation(s)
- Gene S. Fisch
- CUNY/Baruch College; Paul Chook Department of Information Systems & Statistics; New York New York
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12
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Improvement of spatial learning and memory, cortical gyrification patterns and brain oxidative stress markers in diabetic rats treated with Ficus deltoidea leaf extract and vitexin. J Tradit Complement Med 2017; 8:190-202. [PMID: 29322009 PMCID: PMC5755998 DOI: 10.1016/j.jtcme.2017.05.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 05/07/2017] [Accepted: 05/17/2017] [Indexed: 02/07/2023] Open
Abstract
Despite the fact that Ficus deltoidea and vitexin played important roles in controlling hyperglycemia, an effective mitigation strategy dealing with cognitive deficit observed in diabetes, little is known about its neuroprotective effects. The study is aimed to determine changes in behavioral, gyrification patterns and brain oxidative stress markers in streptozotocin (STZ)-induced diabetic rats following F. deltoidea and vitexin treatments. Diabetic rats were treated orally with metformin, methanolic extract of F. deltoidea leaves and vitexin for eight weeks. Morris water maze (MWM) test was performed to evaluate learning and memory functions. The patterns of cortical gyrification were subsequently visualized using micro-computed tomography (micro-CT). Quantification of brain oxidative stress biomarkers, insulin, amylin as well as serum testosterone were measured using a spectrophotometer. The brain fatty acid composition was determined using gas chromatography (GC). Biochemical variation in brain was estimated using Fourier transform infrared (FT-IR) spectroscopy. Results showed that oral administration of F. deltoidea extract and vitexin to diabetic rats attenuated learning and memory impairment, along with several clusters of improved gyrification. Both treatments also caused a significant increase in the superoxide dismutase (SOD) and glutathione peroxidase (GPx) values, as well as a significant reduction of TBARS. Strikingly, improvement of cortical gyrification, spatial learning and memory are supported by serum testosterone levels, fatty acid composition of brain and FT-IR spectra.
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