scholarly journals Using genetics to understand the role of kidney function in COVID-19: a mendelian randomization study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jie V. Zhao ◽  
C. Mary Schooling
Keyword(s):  
Kidney Function ◽  
Lower Risk ◽  
Observational Studies ◽  
Mendelian Randomization ◽  
Drug Repositioning ◽  
Kidney Dysfunction ◽  
Urine Albumin ◽  
Genome Wide ◽  
Treatment Use

Abstract Background Kidney dysfunction occurs in severe COVID-19, and is a predictor of COVID-19 mortality. Whether kidney dysfunction causes severe COVID-19, and hence is a target of intervention, or whether it is a symptom, is unclear because conventional observational studies are open to confounding. To obtain unconfounded estimates, we used Mendelian randomization to examine the role of kidney function in severe COVID-19. Methods We used genome-wide significant, uncorrelated genetic variants to predict kidney function, in terms of estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR), and then assessed whether people with genetically instrumented higher eGFR or lower UACR, an indication of better kidney function, had a lower risk of severe COVID-19 (8779 cases, 1,001,875 controls), using the largest available cohorts with extensive genotyping. For comprehensiveness, we also examined their role in COVID-19 hospitalization (24,274 cases, 2,061,529 controls) and all COVID-19 (1,12,612 cases, 2,474,079 controls). Results Genetically instrumented higher eGFR was associated with lower risk of severe COVID-19 (odds ratio (OR) 0.90, 95% confidence interval (CI) 0.83, 0.98) but not related to COVID-19 hospitalization or infection. Genetically instrumented UACR was not related to COVID-19. Conclusions Kidney function appears to be one of the key targets for severe COVID-19 treatment. Use of available medications to improve kidney function, such as antihypertensives, might be beneficial for COVID-19 treatment, with relevance to drug repositioning.

Stroke Genetics: Turning Discoveries into Clinical Applications

Stroke ◽  
2021 ◽  
Author(s):  
Martin Dichgans ◽  
Nathalie Beaufort ◽  
Stephanie Debette ◽  
Christopher D. Anderson
Keyword(s):  
Mendelian Randomization ◽  
Association Studies ◽  
Clinical Applications ◽  
Risk Scores ◽  
Genome Wide Association Studies ◽  
Neuroprotective Agents ◽  
Experimental Systems ◽  
Genome Wide ◽  
Rapid Pace

The field of medical and population genetics in stroke is moving at a rapid pace and has led to unanticipated opportunities for discovery and clinical applications. Genome-wide association studies have highlighted the role of specific pathways relevant to etiologically defined subtypes of stroke and to stroke as a whole. They have further offered starting points for the exploration of novel pathways and pharmacological strategies in experimental systems. Mendelian randomization studies continue to provide insights in the causal relationships between exposures and outcomes and have become a useful tool for predicting the efficacy and side effects of drugs. Additional applications that have emerged from recent discoveries include risk prediction based on polygenic risk scores and pharmacogenomics. Among the topics currently moving into focus is the genetics of stroke outcome. While still at its infancy, this field is expected to boost the development of neuroprotective agents. We provide a brief overview on recent progress in these areas.

scholarly journals A transcriptome-wide Mendelian randomization study to uncover tissue-dependent regulatory mechanisms across the human phenome

2019 ◽  
Author(s):  
Tom G Richardson ◽  
Gibran Hemani ◽  
Tom R Gaunt ◽  
Caroline L Relton ◽  
George Davey Smith
Keyword(s):  
Gene Expression ◽  
Genetic Variants ◽  
Complex Traits ◽  
Mendelian Randomization ◽  
Drug Repositioning ◽  
Association Studies ◽  
Thyroid Tissue ◽  
Genome Wide Association Studies ◽  
Tissue Specific ◽  
Genome Wide

AbstractBackgroundDeveloping insight into tissue-specific transcriptional mechanisms can help improve our understanding of how genetic variants exert their effects on complex traits and disease. By applying the principles of Mendelian randomization, we have undertaken a systematic analysis to evaluate transcriptome-wide associations between gene expression across 48 different tissue types and 395 complex traits.ResultsOverall, we identified 100,025 gene-trait associations based on conventional genome-wide corrections (P < 5 × 10−08) that also provided evidence of genetic colocalization. These results indicated that genetic variants which influence gene expression levels in multiple tissues are more likely to influence multiple complex traits. We identified many examples of tissue-specific effects, such as genetically-predicted TPO, NR3C2 and SPATA13 expression only associating with thyroid disease in thyroid tissue. Additionally, FBN2 expression was associated with both cardiovascular and lung function traits, but only when analysed in heart and lung tissue respectively.We also demonstrate that conducting phenome-wide evaluations of our results can help flag adverse on-target side effects for therapeutic intervention, as well as propose drug repositioning opportunities. Moreover, we find that exploring the tissue-dependency of associations identified by genome-wide association studies (GWAS) can help elucidate the causal genes and tissues responsible for effects, as well as uncover putative novel associations.ConclusionsThe atlas of tissue-dependent associations we have constructed should prove extremely valuable to future studies investigating the genetic determinants of complex disease. The follow-up analyses we have performed in this study are merely a guide for future research. Conducting similar evaluations can be undertaken systematically at http://mrcieu.mrsoftware.org/Tissue_MR_atlas/.

Identification of ST3AGL4, MFHAS1, CSNK2A2 and CD226 as loci associated with systemic lupus erythematosus (SLE) and evaluation of SLE genetics in drug repositioning

2018 ◽  
Vol 77 (7) ◽  
pp. 1078-1084 ◽  
Author(s):  
Yong-Fei Wang ◽  
Yan Zhang ◽  
Zhengwei Zhu ◽  
Ting-You Wang ◽  
David L Morris ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Fine Mapping ◽  
Lupus Erythematosus ◽  
Drug Repositioning ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Systemic Lupus ◽  
Genome Wide ◽  
Causal Variants

ObjectivesSystemic lupus erythematosus (SLE) is a prototype autoimmune disease with a strong genetic component in its pathogenesis. Through genome-wide association studies (GWAS), we recently identified 10 novel loci associated with SLE and uncovered a number of suggestive loci requiring further validation. This study aimed to validate those loci in independent cohorts and evaluate the role of SLE genetics in drug repositioning.MethodsWe conducted GWAS and replication studies involving 12 280 SLE cases and 18 828 controls, and performed fine-mapping analyses to identify likely causal variants within the newly identified loci. We further scanned drug target databases to evaluate the role of SLE genetics in drug repositioning.ResultsWe identified three novel loci that surpassed genome-wide significance, including ST3AGL4 (rs13238909, pmeta=4.40E-08), MFHAS1 (rs2428, pmeta=1.17E-08) and CSNK2A2 (rs2731783, pmeta=1.08E-09). We also confirmed the association of CD226 locus with SLE (rs763361, pmeta=2.45E-08). Fine-mapping and functional analyses indicated that the putative causal variants in CSNK2A2 locus reside in an enhancer and are associated with expression of CSNK2A2 in B-lymphocytes, suggesting a potential mechanism of association. In addition, we demonstrated that SLE risk genes were more likely to be interacting proteins with targets of approved SLE drugs (OR=2.41, p=1.50E-03) which supports the role of genetic studies to repurpose drugs approved for other diseases for the treatment of SLE.ConclusionThis study identified three novel loci associated with SLE and demonstrated the role of SLE GWAS findings in drug repositioning.

scholarly journals Causal Effects of Homocysteine, Folate, and Cobalamin on Kidney Function: A Mendelian Randomization Study

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 906
Author(s):  
Sehoon Park ◽  
Soojin Lee ◽  
Yaerim Kim ◽  
Semin Cho ◽  
Kwangsoo Kim ◽  
...  
Keyword(s):  
Kidney Function ◽  
Estimated Glomerular Filtration Rate ◽  
Mendelian Randomization ◽  
Homocysteine Level ◽  
Meta Analysis ◽  
Causal Effects ◽  
European Ancestry ◽  
Genome Wide ◽  
Function Impairment ◽  
Genetic Instruments

Blood homocysteine level and related vitamin levels are associated with various health outcomes. We aimed to assess causal effects of blood homocysteine, folate, and cobalamin on kidney function in the general population by performing Mendelian randomization (MR) analysis. Genetic instruments for blood homocysteine, folate, and cobalamin levels were introduced from a previous genome-wide association (GWAS) meta-analysis of European individuals. Summary-level MR analysis was performed for the estimated glomerular filtration rate (eGFR) from the CKDGen consortium GWAS that included 567,460 European ancestry individuals. For replication, allele-score-based MR was performed with an independent U.K. Biobank cohort of 337,138 individuals of white British ancestry. In summary-level MR for the CKDGen data, high genetically predicted homocysteine levels were significantly associated with low eGFR (per 1 standard deviation, beta for eGFR change −0.95 (−1.21, −0.69) %), supported by pleiotropy-robust MR sensitivity analysis. Genetically predicted high folate levels were significantly associated with high eGFR change (0.86 (0.30, 1.42) %); however, causal estimates from cobalamin were nonsignificant (−0.11 (−0.33, 0.11) %). In the U.K. Biobank data, the results were consistently identified. Therefore, a high blood homocysteine level causally decreases eGFR. Future trials with appropriate homocysteine-lowering interventions may be helpful for the primary prevention of kidney function impairment.

scholarly journals Mendelian randomization suggests a bidirectional, causal relationship between physical inactivity and obesity

2021 ◽  
Author(s):  
German Dario Carrasquilla ◽  
Mario García-Ureña ◽  
Tove Fall ◽  
Thorkild IA Sørensen ◽  
Tuomas Kilpeláinen
Keyword(s):  
Physical Activity ◽  
Weight Gain ◽  
Causal Relationship ◽  
Physical Inactivity ◽  
Observational Studies ◽  
Sedentary Time ◽  
Mendelian Randomization ◽  
Genome Wide Association Studies ◽  
Reverse Causality ◽  
Genome Wide

Physical inactivity is associated with excess weight gain in observational studies. However, some longitudinal studies indicate reverse causality where weight gain leads to physical inactivity. As observational studies suffer from reverse causality, it is challenging to assess the true causal directions. Here, we assess the bidirectional causality between physical inactivity and obesity by bidirectional Mendelian randomization analysis. We used results from genome-wide association studies for accelerometer-based physical activity and sedentary time in 91,105 individuals and for body mass index (BMI) in 806,834 individuals. We implemented Mendelian randomization using CAUSE method that accounts for pleiotropy and sample overlap using full genome-wide data. We also applied inverse variance-weighted, MR-Egger, weighted median, and weighted mode methods using genome-wide significant variants only. We found evidence of bidirectional causality between sedentary time and BMI: longer sedentary time was causally associated with higher BMI [beta (95%CI) from CAUSE method: 0.11 (0.02, 0.2), P=0.02], and higher BMI was causally associated with longer sedentary time (0.13 (0.08, 0.17), P=6.3.x10-4). Our analyses suggest that higher moderate and vigorous physical activity are causally associated with lower BMI (moderate: -0.18 (-0.3,-0.05), P=0.006; vigorous: -0.16 (-0.24,-0.08), P=3.8x10-4), but indicate that the association between higher BMI and lower levels of physical activity is due to horizontal pleiotropy. The bidirectional, causal relationship between sedentary time and BMI suggests that decreasing sedentary time is beneficial for weight management, but also that targeting obesity may lead to additional health benefits by reducing sedentary time.

scholarly journals Sex-specific Associations of Sex Hormone Binding Globulin with CKD and Kidney Function: A Univariable and Multivariable Mendelian Randomization Study in the UK Biobank

2020 ◽  
pp. ASN.2020050659
Author(s):  
Jie V. Zhao ◽  
C. Mary Schooling
Keyword(s):  
Kidney Function ◽  
Lower Risk ◽  
Mendelian Randomization ◽  
Sex Hormone ◽  
Sex Hormone Binding Globulin ◽  
Nucleotide Polymorphisms ◽  
Hormone Binding ◽  
Shbg Level ◽  
The Uk ◽  
Sex Disparity

BackgroundKidney function declines faster in men. Testosterone levels may mediate the sex disparity. Correspondingly, levels of sex hormone binding globulin (SHBG), which modulates sex hormones, might also be relevant to the lower kidney function in men. The sex-specific role of SHBG is unclear.MethodsA sex-specific, Mendelian randomization (MR) study provided unconfounded estimates of SHBG levels among the United Kingdom Biobank population. Univariable MR applied 357 single nucleotide polymorphisms (SNPs) in men and 359 SNPs in women. These published SNPs strongly (P<5×10−8) predict SHBG level. They were profiled in 179,916 white British men (6016 patients with CKD) and 212,079 white British women (5958 patients with CKD), to obtain the effect of SHBG on CKD, albuminuria, and eGFR. Multivariable MR controlling for testosterone was used to assess the effect of SHBG on CKD and kidney function independent of testosterone in men.ResultsGenetically predicted higher SHBG was associated with a lower risk of CKD in men (odds ratio [OR], 0.78 per SD; 95% confidence interval [95% CI], 0.65 to 0.93) but had no benefit in women. The effect in men remained in multivariable MR, allowing for testosterone (OR, 0.61; 95% CI, 0.45 to 0.82).ConclusionsGenetically predicted higher SHBG was associated with a lower risk of CKD and better kidney function in men, but not in women, suggesting that SHBG may play a role in CKD specifically in men. Identifying drivers of SHBG and the underlying pathways could provide new insights into CKD prevention and treatment.

scholarly journals Kidney Dysfunction And COVID-19: Characteristics, Predictive Factors, And Influence Of Age

2021 ◽  
Author(s):  
Edoardo La Porta ◽  
Paola Baiardi ◽  
Lorenzo Fassina ◽  
Alessandro Faragli ◽  
Simone Perna ◽  
...  
Keyword(s):  
Kidney Function ◽  
Kidney Injury ◽  
Predictive Analysis ◽  
Kidney Dysfunction ◽  
Reactive Protein ◽  
Hazard Ratios ◽  
Machine Learning Approach ◽  
Severity Of The Disease ◽  
The Relationship

Abstract Background COVID-19 severity and mortality are strongly influenced by age and comorbidities. Among comorbidities, kidney dysfunction seems to play a crucial role. Indeed, acute kidney injury (AKI) is a frequent finding in hospitalized COVID-19 patients and seems to be associated to mortality and severity. On the other hand, the role of chronic kidney disease (CKD) in COVID-19 is more debated. Aims and Methods We performed a retrospective study in a cohort of 174 hospitalized COVID-19 patients in Italy from March 3rd to May 21st 2020, to investigate the role of kidney dysfunction on COVID-19 severity and mortality. Moreover, we examined in depth the relationship between kidney function, age, and progression of COVID-19, also using different equations to estimate the glomerular filtration rate (GFR). Hazard ratios (HR) and odds ratios (OR) were obtained by logistic regression, while a predictive analysis was made through a machine learning approach.Results AKI and death occurred in 10.2 % and 19.5% respectively, in our population. Serum creatinine, blood urea nitrogen, neutrophils, lymphocytes, c-reactive protein and procalcitonin were significantly correlated to mortality and severity of the disease. The major risk factors for mortality in our cohort were age [adjusted HR, 6.2; 95% confidence interval (CI) 1.8-21.4] and AKI [3.36 (1.44-7.87)], while, in these relationships, GFR at the baseline mitigated the role of age. The occurrence of AKI was influenced by baseline kidney function, D-dimer and procalcitonin and hypertension. Our predictive analysis for AKI and mortality reached an accuracy ≥ of 94% and 91%, respectively. In patients ≥ 70 years, MDRD and CKD-EPI showed a better performance in the prediction of AKI and mortality, compared to BIS-1 formula.Discussion Our study confirms the importance of AKI as a risk factor in COVID-19 disease, while it scales down the role of CKD, especially in elderly patients. BIS-1 formula demonstrated a worse performance to predict the outcomes in COVID-19 patients when compared to MDRD and CKD-EPI.

scholarly journals What multiple Mendelian randomization approaches reveal about obesity and gout

2021 ◽  
Author(s):  
Charleen D. Adams ◽  
Brian Boutwell
Keyword(s):  
Observational Studies ◽  
Mendelian Randomization ◽  
Association Studies ◽  
Hdl Cholesterol ◽  
P Value ◽  
Genome Wide Association Studies ◽  
Cholesterol Levels ◽  
Genome Wide ◽  
The Impact ◽  
Apparent Ability

Background/Objectives: Gout is a painful arthritic disease. A robust canon of observational literature suggests strong relationships between obesity, high urate levels, and gout. But findings from observational studies can be fraught with confounding and reverse causation. They can conflict with findings from Mendelian randomization (MR), designed to tackle these biases. We aimed to determine whether the relationships between obesity, higher urate levels, and gout were causal using multiple MR approaches, including an investigation of how other closely related traits, LDL, HDL cholesterol, and triglyceride levels fit into the picture. Subjects/Methods: Summary results from genome-wide association studies of the five above-mentioned traits were extracted and used to perform two-sample (univariable, multivariable, and two-step) MR and MR mediation analysis. Results Obesity increased urate (beta=0.127; 95% CI=0.098, 0.157; P-value=1.2E-17) and triglyceride levels (beta=0.082; 95% CI=0.065, 0.099; P-value=1.2E-21) and decreased HDL cholesterol levels (beta=-0.083; 95% CI=-0.101, -0.065; P-value=2.5E-19). Higher triglyceride levels increased urate levels (beta=0.198; 95% CI=0.146, 0.251; P-value=8.9E-14) and higher HDL levels decreased them (beta=-0.109; 95% CI=-0.148, -0.071; P-value=2.7E-08). Higher urate levels (OR=1.030; 95% CI=1.028, 1.032; P-value=1.1E-130) and obesity caused gout (OR=1.003; 95% CI=1.001, 1.004; P-value=1.3E-04). The mediation MR of obesity on gout with urate levels as a mediator revealed, however, that essentially all of the effect of obesity on gout is mediated through urate. The impact of obesity on LDL cholesterol was null (beta=-0.011; 95% CI=-0.030, 0.008; P-value=2.6E-01), thus it was not included in the multivariable MR. The multivariable MR of obesity, HDL cholesterol, and triglycerides on urate levels revealed that obesity has an effect on urate levels even when accounting for HDL cholesterol and triglyceride levels. Conclusions: Obesity impacts gout indirectly by influencing urate levels and possibly other traits, such as triglycerides, that increase urate levels. Obesity's impact on urate is exacerbated by its apparent ability to decrease HDL cholesterol. 

scholarly journals Physical Activity and Heart Failure: Taking Steps to Control a Major Public Health Burden

2018 ◽  
Vol 14 (6) ◽  
pp. 555-570 ◽  
Author(s):  
Michael J. LaMonte
Keyword(s):  
Physical Activity ◽  
Heart Failure ◽  
Lower Risk ◽  
Coronary Atherosclerosis ◽  
Observational Studies ◽  
Prolonged Exposure ◽  
Clinical Syndrome ◽  
Public Health Burden ◽  
Published Evidence

Heart failure (HF) is a complex clinical syndrome that is increasingly prevalent among US adults and accounts for substantial burden of healthcare costs and morbidity. HF is commonly associated with prior myocardial infarction as well as prolonged exposure to hypertension, diabetes, and coronary atherosclerosis. Exercise training is becoming established in the management of HF because of its beneficial effect on both central (cardiac) and peripheral (skeletal muscle) HF mechanisms. The role of habitual physical activity in the primary prevention of HF is less clear. Recent prospective observational studies suggest there is lower risk of developing HF in adults who are more physically activity and have higher cardiorespiratory fitness compared with their less active and fit peers. This article reviews the published evidence on physical activity and HF prevention, discusses potential mechanisms for this benefit, and suggests areas where further research is needed to establish recommendations on the type, amount, and intensity of physical activity required to prevent occurrence of HF.

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