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To identify functionally related genes associated with diabetic retinopathy (DR) risk using gene set enrichment analyses applied to genome-wide association study meta-analyses.MethodsWe analyzed DR GWAS meta-analyses performed on 3246 Europeans and 2611 African Americans with type 2 diabetes. Gene sets relevant to 5 key DR pathophysiology processes were investigated: tissue injury, vascular events, metabolic events and glial dysregulation, neuronal dysfunction, and inflammation. Keywords relevant to these processes were queried in 4 pathway and ontology databases. Two GSEA methods, Meta-Analysis Gene set Enrichment of variaNT Associations (MAGENTA) and Multi-marker Analysis of GenoMic Annotation (MAGMA), were used. Gene sets were defined to be enriched for gene associations with DR if the P value corrected for multiple testing (Pcorr) was

Background APOL1 variants contribute to the markedly higher incidence of ESKD in Blacks compared with Whites. Genetic testing for these variants in patients with African ancestry who have nephropathy is uncommon, and no specific treatment or management protocol for APOL1-associated nephropathy currently exists. Methods A multidisciplinary, racially diverse group of 14 experts and patient advocates participated in a Delphi consensus process to establish practical guidance for clinicians caring for patients who may have APOL1-associated nephropathy. Consensus group members took part in three anonymous voting rounds to develop consensus statements relating to the following: (1) counseling, genotyping, and diagnosis; (2) disease awareness and education; and (3) a vision for management of APOL1-associated nephropathy in a future when treatment is available. A systematic literature search of the MEDLINE and Embase databases was conducted to identify relevant evidence published from January 1, 2009 to July 14, 2020. Results The consensus group agreed on 55 consensus statements covering such topics as demographic and clinical factors that suggest a patient has APOL1-associated nephropathy, as well as key considerations for counseling, testing, and diagnosis in current clinical practice. They achieved consensus on the need to increase awareness among key stakeholders of racial health disparities in kidney disease and of APOL1-associated nephropathy and on features of a successful education program to raise awareness among the patient community. The group also highlighted the unmet need for a specific treatment and agreed on best practice for management of these patients should a treatment become available. Conclusions A multidisciplinary group of experts and patient advocates defined consensus-based guidance on the care of patients who may have APOL1-associated nephropathy.

APOL1 kidney risk variants (RVs) were identified in 2010 as major drivers of glomerular, tubulointerstitial and renal microvascular disease in individuals with sub-Saharan African ancestry. In December 2020, the “APOL1 at Ten” conference summarized the first decade of progress and discussed controversies and uncertainties that remain to be addressed. Topics included trypanosome infection and its role in the evolution of APOL1 kidney RVs, clinical phenotypes in APOL1-associated nephropathy, relationships between APOL1 RVs and background haplotypes on cell injury and molecular mechanisms initiating disease, the role of clinical APOL1 genotyping, and development of novel therapies for kidney disease. Future goals were defined, including improved characterization of various APOL1 RV phenotypes in patients and experimental pre-clinical models; further dissection of APOL1-mediated pathways to cellular injury and dysfunction in kidney (and other) cells; clarification of gene-gene and gene-environment interactions; and evaluation of the role for existing and novel therapies.

The application of deep learning for automated segmentation (delineation of boundaries) of histologic primitives (structures) from whole slide images can facilitate the establishment of novel protocols for kidney biopsy assessment. Here, we developed and validated deep learning networks for the segmentation of histologic structures on kidney biopsies and nephrectomies. For development, we examined 125 biopsies for Minimal Change Disease collected across 29 NEPTUNE enrolling centers along with 459 whole slide images stained with Hematoxylin & Eosin (125), Periodic Acid Schiff (125), Silver (102), and Trichrome (107) divided into training, validation and testing sets (ratio 6:1:3). Histologic structures were manually segmented (30048 total annotations) by five nephropathologists. Twenty deep learning models were trained with optimal digital magnification across the structures and stains. Periodic Acid Schiff-stained whole slide images yielded the best concordance between pathologists and deep learning segmentation across all structures (F-scores: 0.93 for glomerular tufts, 0.94 for glomerular tuft plus Bowman's capsule, 0.91 for proximal tubules, 0.93 for distal tubular segments, 0.81 for peritubular capillaries, and 0.85 for arteries and afferent arterioles). Optimal digital magnifications were 5X for glomerular tuft/tuft plus Bowman's capsule, 10X for proximal/distal tubule, arteries and afferent arterioles, and 40X for peritubular capillaries. Silver stained whole slide images yielded the worst deep learning performance. Thus, this largest study to date adapted deep learning for the segmentation of kidney histologic structures across multiple stains and pathology laboratories. All data used for training and testing and a detailed online tutorial will be publicly available.

Background: Kidney risk variants (KRVs) in the apolipoprotein L1 gene (APOL1) are associated with mitochondrial dysfunction. However, the molecular spectrum of metabolites impacted by the G1 and G2 KRVs and the downstream mitochondrial pathways they affect remain unknown. Methods: We performed a metabolomics analysis using HEK293 Tet-on cells conditionally expressing APOL1 G0, and G1 and G2 KRVs to determine the patterns of metabolites and pathways potentially involved in nephropathy. Welch9s two-sample t-test, matched pairs t-test, and two-way repeated measures ANOVA were employed to identify differential metabolites. Random Forest, a supervised classification algorithm that uses an ensemble of decision trees, and the mean decrease accuracy (MDA) metric were applied to prioritize top metabolites. Results: Alterations in the tricarboxylic acid cycle, increased fatty acid oxidation, and compromised redox homeostasis were the major pathways impacted by overexpression of APOL1 KRVs. Conclusion: Impairment of mitochondrial membrane respiratory chain complex I appeared to account for critical metabolic consequences of APOL1 KRVs. This finding supports depletion of the mitochondrial membrane potential, as has been reported.

Intensive blood pressure control decreases the rate of cardiovascular events by >25% compared with standard blood pressure control. We sought to determine whether the decrease in cardiovascular events seen with intensive blood pressure control is associated with an increased rate of other causes of hospitalization. This is a post hoc analysis of SPRINT (Systolic Blood Pressure Intervention Trial) in 9361 adult participants with hypertension and elevated cardiovascular risk. Participants were randomly assigned to an intensive or standard systolic blood pressure goal (P =0.37). Equivalence testing shows that these hospitalization rates were statistically equivalent at the P =0.05 level. Of those with hospitalizations, >1 hospitalization was seen in 38.8% of intensive arm participants and 41.9% of standard arm participants ( P =0.08). The mean cumulative count of nonprimary event hospitalizations was comparable between the two arms. The most common causes of hospitalization were cardiovascular (23.6%) followed by injuries, including bone and joint therapeutic procedures (15.7%), infections (12.0%), and nervous systems disorders (10.7%). No categories of hospitalization were statistically more common in the intensive arm compared with the standard arm. Thus, the decrease in cardiovascular events seen with intensive blood pressure control is not associated with an increased rate of other causes of hospitalization. Registration— URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01206062.

Apolipoprotein L1 (APOL1) high-risk genotypes strongly associate with HIV-associated nephropathy, and antiretroviral therapy reduces the incidence of HIV-associated nephropathy and progression to end-stage kidney disease. Wudil et al. report cross-sectional APOL1 associations with proteinuria and estimated glomerular filtration rate in a northern Nigerian sample with HIV infection on antiretroviral therapy. Multiple ethnic groups with different APOL1 risk variant frequencies were included. Overall, APOL1 was associated with proteinuric chronic kidney disease; however, relationships with underlying causes of nephropathy and progression rates require further study.

This study evaluated intradialytic cerebral hemodynamics measured by transcranial Doppler (TCD) in intermittent hemodialysis (iHD) versus nightly peritoneal dialysis (NIPD). Intradialytic TCD was serially performed in chronic dialysis patients receiving iHD ( n = 10) and NIPD ( n = 10). A linear mixed model was used to model mean flow velocity (MFV), pulsatility index (PI), and mean arterial pressure (MAP) as functions of time and treatment group. Intradialytic cerebral volatility (IDCV) was calculated using the coefficient of variation (CV) and mean absolute value of change (AVC) of each patient’s MFV, PI, and MAP values over time. Mixed model analyses found no significant difference between MFV, PI, and MAP treatment groups in change over time, though volatility differed significantly. Mean CV values for MFV, PI, and MAP were higher in iHD than NIPD (MFV 0.22 vs. 0.10, p = 0.005; PI 0.14 vs. 0.08, p = 0.003; MAP 0.057 vs. 0.032, p = 0.009). AVC values were similarly higher in iHD compared to NIPD (MFV 8.26 vs. 4.43, p = 0.04; PI 0.17 vs. 0.084, p < 0.001; MAP 6.05 vs. 2.9, p = 0.003). PI, MFV, and MAP were more stable in NIPD than iHD, as measured by intradialytic TCD monitoring. This study identifies IDCV as a unique TCD metric for intradialytic cerebral hemodynamics.

Background and objectives It is unclear whether the presence of albuminuria modifies the effects of intensive systolic BP control on risk of eGFR decline, cardiovascular events, or mortality. Design, setting, participants, & measurements The Systolic Blood Pressure Intervention Trial randomized nondiabetic adults ≥50 years of age at high cardiovascular risk to a systolic BP target of Results Over a median follow-up of 3.1 years, 69 of 1723 (4%) participants with baseline albuminuria developed ≥40% eGFR decline compared with 61 of 7162 (1%) participants without albuminuria. Incidence rates of ≥40% eGFR decline were higher in participants with albuminuria (intensive, 1.74 per 100 person-years; standard, 1.17 per 100 person-years) than in participants without albuminuria (intensive, 0.48 per 100 person-years; standard, 0.11 per 100 person-years). Although effects of intensive BP lowering on ≥40% eGFR decline varied by albuminuria on the relative scale (hazard ratio, 1.48; 95% confidence interval, 0.91 to 2.39 for albumin-creatinine ratio ≥30 mg/g; hazard ratio, 4.55; 95% confidence interval, 2.37 to 8.75 for albumin-creatinine ratio Conclusions Albuminuria did not modify the absolute benefits and risks of intensive systolic BP lowering.

Background: Apolipoprotein L1 gene (APOL1) G1 and G2 kidney-risk variants (KRVs) cause CKD in African Americans, inducing mitochondrial dysfunction. Modifying factors are required, because a minority of individuals with APOL1 high-risk genotypes develop nephropathy. Given that APOL1 function is pH-sensitive and the pH of the kidney interstitium is APOL1 KRV-induced mitochondrial dysfunction. Methods: Human embryonic kidney (HEK293) cells conditionally expressing empty vector (EV), APOL1-reference G0, and G1 or G2 KRVs were incubated in media pH 6.8 or 7.4 for 4, 6, or 8 h. Genotype-specific pH effects on mitochondrial length (µm) were assessed using confocal microscopy in live cells and Fiji derivative of ImageJ software with MiNA plug-in. Lower mitochondrial length indicated fragmentation and early dysfunction. Results: After 6 h doxycycline (Dox) induction in pH 6.8 media, G2-expressing cells had shorter mitochondria (6.54 ± 0.40) than cells expressing EV (7.65 ± 0.72, p = 0.02) or G0 (7.46 ± 0.31, p = 0.003). After 8 h Dox induction in pH 6.8 media, both G1- (6.21 ± 0.26) and G2-expressing cells had shorter mitochondria (6.46 ± 0.34) than cells expressing EV (7.13 ± 0.32, p = 0.002 and p = 0.008, respectively) or G0 (7.22 ± 0.45, p = 0.003 and p = 0.01, respectively). Mitochondrial length in cells incubated in pH 7.4 media were comparable after 8 h Dox induction regardless of genotype. APOL1 mRNA expression and cell viability were comparable regardless of pH or genotype after 8 h Dox induction. Conclusion: Acidic pH facilitates early mitochondrial dysfunction induced by APOL1 G1 and G2 KRVs in HEK293 cells. We propose that the acidic kidney interstitium may play a role in APOL1-mediated mitochondrial pathophysiology and nephropathy.

The landscape in nephrology changed dramatically in 2010 with the discovery of genetic association between two coding renal-risk variants (RRVs) in the apo L1 gene ( APOL1 ) and CKD (1). The APOL1 G1 and G2 nephropathy-associated variants arose

Chronic kidney disease (CKD) independently increases the risk of stroke and small vessel disease (SVD). This study compared SVD and a transcranial Doppler (TCD)-based marker of intracranial vascular resistance (pulsatility index, PI) in post-stroke patients with and without CKD. Between January 2015 and December 2017, 118 individuals with stable eGFR (50 with CKD) had cerebral MRI and TCD within three months of a stroke. The means of bilateral PI in anterior (anterior cerebral [ACA] and middle cerebral arteries [MCA]) and posterior vessels (posterior cerebral [PCA] and vertebral arteries [VA]) were computed. CKD strongly correlated with higher distal resistance (median CKD ACA PI 1.2, IQR 1.0 to 1.35 vs. controls 0.91 IQR 0.79 to 1.1 [ p 4 IQR 2.66 to 7.76 × 104 voxels vs. controls median SVD 6.7 × 103 IQR 2.4 to 24.0 × 103 [ p

BACKGROUND: Although gastroparesis is seen in patients with type 2 diabetes mellitus (T2DM), the prevalence of symptoms suggestive of gastroparesis in patients with T2DM is unknown, particularly among African Americans. AIMS: To determine the prevalence of symptoms associated with gastroparesis in a large community-based population of European Americans and African Americans with T2DM. METHODS: Individuals with T2DM in the Diabetes Heart Study were asked to complete the gastroparesis cardinal symptom index (GCSI) and other GI-related questionnaires. GCSI total score ≥ 18 represented moderate or worse symptoms suggestive of gastroparesis. RESULTS: A total of 1253 participants (700 female, 553 male) completed the GCSI: 750 were European American and 503 African American. GCSI scores ≥ 18 were recorded in 72 participants: 38 (5%) of European Americans and 34 (7%) of African Americans. The average GCSI was 24.1 in European Americans and 24.6 in African Americans, indicating moderate to severe symptoms. Compared to European Americans with GCSI scores ≥ 18, African Americans were younger (59.4 vs. 53.3 years, p = 0.004), had earlier onset of T2DM (46.3 vs. 40.1 years, p = 0.01), higher HbA1c (7.6 vs. 9.1, p = 0.0009), underwent fewer upper endoscopies (55.3% vs. 26.5%, p = 0.02), and had more anxiety and depression (p < 0.001). CONCLUSIONS: Moderate or greater symptoms suggestive of gastroparesis are present in 5–7% of European and African American patients with T2DM in community-based populations. Symptoms suggestive of gastroparesis may be underappreciated in patients with T2DM and account for upper gastrointestinal symptoms, unexplained glycemic control issues, and decreased quality of life.

Introduction Much of the higher risk for end-stage kidney disease (ESKD) in African American individuals relates to ancestry-specific variation in the apolipoprotein L1 gene (APOL1). Relative to kidneys from European American deceased-donors, kidneys from African American deceased-donors have shorter allograft survival and African American living-kidney donors more often develop ESKD. The National Institutes of Health (NIH)–sponsored APOL1 Long-term Kidney Transplantation Outcomes Network (APOLLO) is prospectively assessing kidney allograft survival from donors with recent African ancestry based on donor and recipient APOL1 genotypes. Methods APOLLO will evaluate outcomes from 2614 deceased kidney donor-recipient pairs, as well as additional living-kidney donor-recipient pairs and unpaired deceased-donor kidneys. Results The United Network for Organ Sharing (UNOS), Association of Organ Procurement Organizations, American Society of Transplantation, American Society for Histocompatibility and Immunogenetics, and nearly all U.S. kidney transplant programs, organ procurement organizations (OPOs), and histocompatibility laboratories are participating in this observational study. APOLLO employs a central institutional review board (cIRB) and maintains voluntary partnerships with OPOs and histocompatibility laboratories. A Community Advisory Council composed of African American individuals with a personal or family history of kidney disease has advised the NIH Project Office and Steering Committee since inception. UNOS is providing data for outcome analyses. Conclusion This article describes unique aspects of the protocol, design, and performance of APOLLO. Results will guide use of APOL1 genotypic data to improve the assessment of quality in deceased-donor kidneys and could increase numbers of transplanted kidneys, reduce rates of discard, and improve the safety of living-kidney donation., Graphical abstract

BackgroundCompared to European, Asian and Native Americans, African Americans have a 3-fold higher risk of developing end-stage kidney disease (ESKD) and are more likely to develop severe lupus nephritis (LN).MethodsStrong genetic association is observed between the apolipoprotein L1 gene (APOL1) and a spectrum of non-diabetic chronic kidney diseases (CKD) in African Americans, including LN, focal segmental glomerulosclerosis, solidified glomerulosclerosis (hypertension-attributed nephropathy), HIV-associated nephropathy, sickle cell nephropathy, and premature failure of transplanted kidneys from APOL1 high-risk donors. APOL1 risk variants arose in sub-Saharan Africa and are present only in those who possess recent African ancestry. These variants account for much of the excess risk for LN and CKD in African Americans. Studies in transgenic mice prove that APOL1 risk variants cause CKD. Kidney disease is due to locally produced APOL1 protein in kidney cells, not circulating APOL1 protein in the blood.ResultsPatients with systemic lupus erythematosus who inherit two APOL1 risk variants are more likely to progress to ESKD and often display focal and diffuse proliferative or membranous glomerular lesions. Kidney disease often progresses despite cytotoxic therapy. In contrast, APOL1 is not associated with mild LN. Therefore, APOL1 risk variants are nephropathy progression factors. Not all individuals with two APOL1 risk variants develop CKD;modifying factors are required. HIV infection, SARS-CoV-2 infection, and interferon are powerful second hits that initiate nephropathy in genetically susceptible hosts.ConclusionsConventional treatments for kidney disease often fail to halt the progression of non-diabetic CKD. Novel small molecule inhibitors of APOL1 protein and APOL1 anti-sense oligonucleotides hold great promise for slowing progression of APOL1-associated nephropathy, including LN. Treatments have the potential to reduce disparities in CKD risk among individuals with African ancestry. In addition, the NIH ‘APOL1 Long-term Kidney Transplant Outcomes’ (APOLLO) Consortium is considering the role of APOL1 genotyping in deceased African American kidney donors to improve organ allocation. Discovery of the APOL1 genetic association with nephropathy in the lab has moved to the bedside and will improve patient outcomes.

Plasma lipids are heritable modifiable causal factors for coronary artery disease, the leading cause of death globally. Despite the well-described monogenic and polygenic bases of dyslipidemia, limitations remain in discovery of lipid-associated alleles using whole genome sequencing, partly due to limited sample sizes, ancestral diversity, and interpretation of potential clinical significance. Increasingly larger whole genome sequence datasets with plasma lipids coupled with methodologic advances enable us to more fully catalog the allelic spectrum for lipids. Here, among 66,329 ancestrally diverse (56% non-European ancestry) participants, we associate 428M variants from deep-coverage whole genome sequences with plasma lipids. Approximately 400M of these variants were not studied in prior lipids genetic analyses. We find multiple lipid-related genes strongly associated with plasma lipids through analysis of common and rare coding variants. We additionally discover several significantly associated rare non-coding variants largely at Mendelian lipid genes. Notably, we detect rareLDLRintronic variants associated with markedly increased LDL-C, similar to rareLDLRexonic variants. In conclusion, we conducted a systematic whole genome scan for plasma lipids expanding the alleles linked to lipids for multiple ancestries and characterize a clinically-relevant rare non-coding variant model for lipids.

RATIONALE AND OBJECTIVE: The safety of intensive blood pressure (BP) targets is controversial for persons with chronic kidney disease (CKD). We studied the effects of hypertension treatment on cerebral perfusion and structure in those with and without CKD. STUDY DESIGN: Neuroimaging substudy of a randomized trial. SETTING & PARTICIPANTS: A subset of participants in the Systolic Blood Pressure Intervention Trial who underwent brain MRI studies. Presence of baseline CKD was assessed by estimated glomerular filtration rate (eGFR) and urine albumin to creatinine ratio (UACR). INTERVENTION: Participants were randomly assigned to intensive (systolic BP 30 mg/g (N=151), the effects of intensive versus standard BP treatment on change in global cerebral blood flow, WMLs and total brain volume were 1.91 ml/100g/min (95% CI −3.01, 6.82), 0.003 cm(3) (asinh transformed, 95% CI −0.13, 0.13), and −7.0 cm(3) (95% CI −13.3, −0.3), respectively. The overall treatment effects on cerebral blood flow and total brain volume were not modified by baseline eGFR or UACR; however the effect on WMLs was attenuated in participants with albuminuria (interaction p-value 0.04). LIMITATIONS: Measurement variability due to multi-site design. CONCLUSIONS: Among hypertensive adults with primarily early kidney disease, intensive versus standard blood pressure treatment did not appear to have a detrimental effect on brain perfusion or structure. The findings support the safety of intensive blood pressure treatment targets on brain health in persons with early kidney disease. FUNDING: The Systolic Blood Pressure Intervention Trial was funded by the National Institutes of Health (including the National Heart, Lung, and Blood Institute, the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institute on Aging, and the National Institute of Neurological Disorders and Stroke), and this substudy was funded by the National Institutes of Diabetes and Digestive and Kidney Diseases. TRIAL REGISTRATION: SPRINT was registered at ClinicalTrials.gov with the study number NCT01206062.

Background: African American (AA) recipients of deceased-donor (DD) kidney transplants (KT) have shorter allograft survival than recipients of other ethnic groups. Reasons for this disparity encompass complex interactions between donors and recipients characteristics. Methods: Outcomes from 3,872 AA and 19,719 European American (EA) DDs who had one kidney transplanted in an AA recipient and one in an EA recipient were analyzed. Four donor/recipient pair groups (DRP) were studied, AA/AA, AA/EA, EA/AA, and EA/EA. Survival random forests and Cox proportional hazard models were fitted to rank and evaluate modifying effects of DRP on variables associated with allograft survival. These analyses sought to identify factors contributing to the observed disparities in transplant outcomes among AA and EA DDKT recipients. Results: Transplant era, discharge serum creatinine, delayed graft function, and DRP were among the top predictors of allograft survival and mortality among DDKT recipients. Interaction effects between DRP with the kidney donor risk index and transplant era showed significant improvement in allograft survival over time in EA recipients. However, AA recipients appeared to have similar or poorer outcomes for DDKT performed after 2010 versus before 2001; allograft survival hazard ratios (95% CI) were 1.15 (0.74, 1.76) and 1.07 (0.8, 1.45) for AA/AA and EA/AA, compared to 0.62 (0.54, 0.71) and 0.5 (0.41, 0.62) for EA/EA and AA/EA DRP, respectively. Recipient mortality improved over time among all DRP, except unemployed AA/AAs. Relative to DDKT performed pre-2001, employed AA/AAs had HR=0.37 (0.2, 0.69) versus 0.59 (0.31, 1.11) for unemployed AA/AA after 2010. Conclusion: Relative to DDKT performed before 2001, similar or worse overall DCAS was observed among AA/AAs, while EA/EAs experienced considerable improvement regardless of employment status, KDRI, and EPTS. AA recipients of an AA DDKT, especially if unemployed, had worse allograft survival and mortality and did not appear to benefit from advances in care over the past 20 years.

Despite the high prevalence and economic burden of chronic kidney disease (CKD) in the United States, federal funding for kidney-related research, prevention, and education activities under the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) remains substantially lower compared to other chronic diseases. More federal support is needed to promote critical research that will expand knowledge of kidney health and disease, develop new and effective therapies, and reduce health disparities. In 2021, the National Kidney Foundation (NKF) convened 2 Research Roundtables (preclinical and clinical research), comprising nephrology leaders from prominent US academic institutions and the pharmaceutical industry, key bodies with expertise in research, and including individuals with CKD and their caregivers and kidney donors. The goal of these roundtables was to identify priorities for preclinical and clinical kidney-related research. The research priorities identified by the Research Roundtables and presented in this position statement outline attainable opportunities for groundbreaking and critically needed innovations that will benefit patients with kidney disease in the next 5-10 years. Research priorities fall within 4 preclinical science themes (expand data science capability, define kidney disease mechanisms and utilize genetic tools to identify new therapeutic targets, develop better models of human disease, and test cell-specific drug delivery systems and utilize gene editing) and 3 clinical science themes (expand number and inclusivity of clinical trials, develop and test interventions to reduce health disparities, and support implementation science). These priorities in kidney-related research, if supported by additional funding by federal agencies, will increase our understanding of the development and progression of kidney disease among diverse populations, attract additional industry investment, and lead to new and more personalized treatments.

Background: Coronary artery calcification (CAC) and carotid artery intima-media thickness (cIMT) are measures of subclinical atherosclerosis in asymptomatic individuals and strong risk factors for cardiovascular disease. Type 2 diabetes (T2D) is an independent cardiovascular disease risk factor that accelerates atherosclerosis. Methods: We performed meta-analyses of genome-wide association studies in up to 2500 T2D individuals of European ancestry (EA) and 1590 T2D individuals of African ancestry with or without exclusion of prevalent cardiovascular disease, for CAC measured by cardiac computed tomography, and 3608 individuals of EA and 838 individuals of African ancestry with T2D for cIMT measured by ultrasonography within the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) Consortium. Results: We replicated 2 loci (rs9369640 and rs9349379 near PHACTR1 and rs10757278 near CDKN2B ) for CAC and one locus for cIMT (rs7412 and rs445925 near APOE-APOC1 ) that were previously reported in the general EA populations. We identified one novel CAC locus (rs8000449 near CSNK1A1L/LINC00547/POSTN at 13q13.3) at P =2.0×10 -8 in EA. No additional loci were identified with the meta-analyses of EA and African ancestry. The expression quantitative trait loci analysis with nearby expressed genes derived from arterial wall and metabolic tissues from the Genotype-Tissue Expression project pinpoints POSTN , encoding a matricellular protein involved in bone formation and bone matrix organization, as the potential candidate gene at this locus. In addition, we found significant associations ( P -4 ) for 3 previously reported coronary artery disease loci for these subclinical atherosclerotic phenotypes (rs2891168 near CDKN2B-AS1 and rs11170820 near FLJ12825 for CAC, and rs7412 near APOE for cIMT). Conclusions: Our results provide potential biological mechanisms that could link CAC and cIMT to increased cardiovascular disease risk in individuals with T2D.

Essential hypertension is a clinical diagnosis based upon the presence of an elevated systemic blood pressure on physical examination without a clear inciting cause. It has multiple etiologies and is not a homogeneous disorder. Hypertension contributes to the development and progression of atherosclerotic cardiovascular disease and anti-hypertensive treatment reduces the risk of fatal and non-fatal myocardial infarction, stroke and congestive heart failure. Although hypertension is frequently present in non-diabetic individuals with low levels of proteinuria and chronic kidney disease, reducing blood pressures in this population does not reliably slow nephropathy progression. Many of these patients with recent African ancestry have the primary kidney disease “solidified glomerulosclerosis” that is strongly associated with apolipoprotein L1 gene (APOL1) renal-risk variants. This kidney disease contributes to secondarily elevated blood pressures. The APOL1-associated spectrum of non-diabetic nephropathy also includes proteinuric kidney diseases idiopathic focal segmental glomerulosclerosis (FSGS), collapsing glomerulopathy, severe lupus nephritis and sickle cell nephropathy. This article reviews relationships between mild-to-moderate essential hypertension and chronic kidney disease with a focus on the role of APOL1 in development of hypertension. Available evidence strongly supports that APOL1 renal-risk variants associate with glomerulosclerosis in African Americans which then causes secondary hypertension, not with essential hypertension per se.

BACKGROUND: An improved understanding of the pathogenesis in apolipoprotein L1 gene (APOL1)-gene associated chronic kidney disease (CKD) arose from observations in kidney transplantation. APOL1 genotyping could soon improve the safety of living kidney donation in individuals with recent African ancestry and alter the allocation of deceased donor kidneys. METHODS: This manuscript reviews the potential mechanisms that underlie development of APOL1-associated nephropathy. Roles for circulating APOL1 protein versus intrinsic renal expression of APOL1 are discussed, as well as the requirement for modifying genetic and/or environmental factors. RESULTS: Abundant evidence supports local kidney production of APOL1 renal-risk variant protein in the development of nephropathy; this is true in both native kidney disease and after renal transplantation. Only a minority of kidneys from individuals with APOL1 high-risk genotypes will develop CKD or manifest shorter renal allograft survival after transplantation. Therefore, modifying factors that explain why only a subset of kidneys develops nephropathy remain critical to identify. It appears likely that environmental exposures, as opposed to major APOL1-second gene interactions, will prove to be stronger modifiers of the risk for nephropathy. CONCLUSIONS: The evolving understanding of the pathogenesis in APOL1-associated nephropathy will identify biomarkers predicting nephropathy in individuals at high genetic risk and lead to novel therapies to prevent or slow native CKD progression and prolong survival of transplanted kidneys. In the interim, the National Institutes of Health-sponsored “APOL1 Long-term Kidney Transplantation Outcomes” (APOLLO) Network will determine whether APOL1 genotyping in individuals with recent African ancestry improves outcomes and safety in kidney transplantation.

© The Author(s) 2019. A person's lipid profile is influenced by genetic variants and alcohol consumption, but the contribution of interactions between these exposures has not been studied. We therefore incorporated gene-Alcohol interactions into a multiancestry genome-wide association study of levels of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides. We included 45 studies in stage 1 (genome-wide discovery) and 66 studies in stage 2 (focused follow-up), for a total of 394,584 individuals from 5 ancestry groups. Analyses covered the period July 2014-November 2017. Genetic main effects and interaction effects were jointly assessed by means of a 2- degrees-of-freedom (df) test, and a 1-df test was used to assess the interaction effects alone. Variants at 495 loci were at least suggestively associated (P < 1 × 10?6) with lipid levels in stage 1 and were evaluated in stage 2, followed by combined analyses of stage 1 and stage 2. In the combined analysis of stages 1 and 2, a total of 147 independent loci were associated with lipid levels at P < 5 × 10?8 using 2-df tests, of which 18 were novel. No genome-wide-significant associations were found testing the interaction effect alone. The novel loci included several genes (proprotein convertase subtilisin/kexin type 5 (PCSK5), vascular endothelial growth factor B (VEGFB), and apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1 (APOBEC1) complementation factor (A1CF)) that have a putative role in lipid metabolism on the basis of existing evidence from cellular and experimental models. National Heart, Lung, and Blood Institute; American Heart Association Grant

Background: Given the increasing worldwide prevalence of chronic kidney disease (CKD), it is critical to decrease the associated risk of debilitating vascular complications, including stroke, congestive heart failure, myocardial infarction, and peripheral vascular disease. Treatment options for reducing the risk of all subtypes of stroke in patients with CKD remain limited. For patients with end-stage kidney disease (ESKD), novel applications of noninvasive imaging may help personalize the type of dialysis and dialysis prescription for patients at high-risk. Summary: This manuscript reviews the heightened risk of stroke in patients with nephropathy, including ischemic and hemorrhagic subtypes. Mechanisms associated with increased risk include alterations in cardiac output, platelet function, regional cerebral perfusion, accelerated systemic atherosclerosis, altered blood brain barrier, and disordered neurovascular coupling. There is great potential for noninvasive monitoring of the cerebral vasculature using transcranial Doppler (TCD) to reduce stroke risk, particularly in patients with ESKD. Key Messages: Compared to the general population, patients with CKD are at heightened risk for all subtypes of stroke. This is due to a multitude of mechanisms linking nephropathy with altered cerebral perfusion, cerebral neurovascular coupling, and blood vessel integrity. Intracranial imaging is not currently standard of care practice in patients with CKD or ESKD. TCD may provide clinicians real-time and noninvasive measurement of brain perfusion. This could be useful for assessing risk of stroke in patients’ initiating dialysis, individualizing dialysis prescriptions, and potentially reducing rates of cerebrovascular disease and stroke in high-risk patients.

Purpose To find genetic contributions to glaucoma in African Americans. Design Cross-sectional, case-control study. Participants One thousand eight hundred seventy-five primary open-angle glaucoma (POAG) patients and 1709 controls, self-identified as being of African descent (AD), from the African Descent and Glaucoma Evaluation Study (ADAGES) III and Wake Forest School of Medicine. Methods MegaChip genotypes were imputed to Thousand Genomes data. Association of single nucleotide polymorphisms (SNPs) with POAG and advanced POAG was tested by linear mixed model correcting for relatedness and population stratification. Genetic risk scores were tested by receiver operator characteristic curves (ROC-AUCs). Main Outcome Measures Primary open-angle glaucoma defined by visual field loss without other nonocular conditions (n = 1875). Advanced POAG was defined by age-based mean deviation of visual field (n = 946). Results Eighteen million two hundred eighty-one thousand nine hundred twenty SNPs met imputation quality of r2 > 0.7 and minor allele frequency > 0.005. Association of a novel locus, EN04, was observed for advanced POAG (rs185815146 β, 0.36; standard error, 0.065; P Conclusions A novel association with advanced POAG in the EN04 locus was identified putatively in persons of AD. In addition to this finding, this genome-wide association study in POAG patients of AD contributes to POAG genetics by identification of novel signals in prior loci (9p21), as well as advancing the fine mapping of regions because of shorter average LD (FNDC3B). Although not useful without confirmation and clinical trials, the use of genetic risk scores demonstrated that considerable AD-specific genetic information remains in these data.

Background: Kidney tubulointerstitial fibrosis on biopsy is a strong predictor of chronic kidney disease (CKD) progression, and CKD is associated with elevated risk of cardiovascular disease (CVD). Tubular health is poorly quantified by traditional kidney function measures, including estimated glomerular filtration rate (eGFR) and albuminuria. We hypothesized that urinary biomarkers of tubular injury, inflammation, and repair would be associated with higher risk of CVD and mortality in persons with CKD. Methods: We measured urinary concentrations of interleukin-18 (IL-18), kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and chitinase-3-like protein-1 (YKL-40) at baseline among 2,377 participants of the Systolic Blood Pressure Intervention Trial who had an eGFR < 60 mL/min/1.73 m2. We used Cox proportional hazards models to evaluate biomarker associations with CVD events and all-cause mortality. Results: At baseline, the mean age of participants was 72 ± 9 years, and eGFR was 48 ± 11 mL/min/1.73 m2. Over a median follow-up of 3.8 years, 305 CVD events (3.6% per year) and 233 all-cause deaths (2.6% per year) occurred. After multivariable adjustment including eGFR, albuminuria, and urinary creatinine, none of the biomarkers showed statistically significant associations with CVD risk. Urinary IL-18 (hazard ratio [HR] per 2-fold higher value, 1.14; 95% CI 1.01–1.29) and YKL-40 (HR per 2-fold higher value, 1.08; 95% CI 1.02–1.14) concentrations were each incrementally associated with higher mortality risk. Associations were similar when stratified by randomized blood pressure arm. Conclusions: Among hypertensive trial participants with CKD, higher urinary IL-18 and YKL-40 were associated with higher risk of mortality, but not CVD.

Background: Apolipoprotein A1 (APOL1) gene variants occurring in people of West African descent contribute to the greater burden of kidney disease among African Americans. These variants are associated with increased risk of nondiabetic nephropathy, more rapid progression of chronic kidney disease, and shorter survival of donor kidneys after transplantation. However, only a minority of people with APOL1-associated risk develops kidney disease and specific clinical measures to address APOL1-associated risk are lacking. Given these uncertainties, we sought to engage members of the African American public in discussions with other stakeholders about the appropriate use of APOL1 testing. Methods: Formative interviews with community members, researchers, and clinicians in Seattle WA, Nashville TN, and Jackson MS, provided baseline information about views toward APOL1 testing and informed the design of 3 community-based deliberations among African Americans. A national meeting held in March 2018 included 13 community members, 7 scientific advisors and 26 additional researchers, clinicians, bioethicists, patient advocates, and representatives from professional organizations and federal funding agencies. Using small break-out and plenary discussion, the group agreed on recommendations based on current knowledge about APOL1-associated risk. Results: Meeting outcomes included recommendations to develop educational materials about APOL1 for community members and clinicians; to offer APOL1 research results to participants; and on the use of APOL1testing in kidney transplant programs. The group recommended against the routine offer of APOL1 testing in clinical care. Areas of disagreement included whether kidney transplant programs should require APOL1 testing of prospective living donors or bar individuals with APOL1 risk from donating kidneys and whether testing should be available on request in routine clinical care. Conclusion: We recommend continued discussion among stakeholders and concerted efforts to ensure active and informed participation of members of the affected community to guide research on APOL1 and kidney disease.

Background: Appendicular skeletal muscle mass index and muscle attenuation (density) are negatively associated with mortality in European-derived populations. Objectives: The present analyses assessed association between axial skeletal muscle density and muscle index with mortality in European Americans with type 2 diabetes mellitus (T2D). Design: Single-center observational study. Setting: Diabetes Heart Study. Participants: 839 European Americans with T2D. Methods: Computed tomography-measured psoas and paraspinous muscle mass index (cross sectional area/height2) and radiographic density (Hounsfield Units) were assessed in all participants. A Cox proportional hazards model was computed. The fully-adjusted model included covariates age, sex, body mass index, smoking, alcohol use, diabetes duration, insulin use, hormone replacement therapy (women), prevalent cardiovascular disease (CVD), hypertension, and coronary artery calcified atherosclerotic plaque mass score. Deaths were recorded in the National Death Index data through December 31, 2015. Results: Participants included 428 women and 411 men with median (25th, 75th quartile) age 62.8 (56.1, 69.1) years and diabetes duration 8.0 (5.0, 14.0) years. After 11.9 (9.4, 13.3) years of follow-up, 314 (37.4%) of participants were deceased. In the fully-adjusted model, psoas muscle density (hazard ratio [HR] 0.81, p

Purpose of review The presence of viruses in urine (urine virome) typically reflects infection in the kidneys and urinary tract. The urinary virome is associated with HIV-associated nephropathy and chronic glomerulosclerosis. There are many associations of this microbiome with human diseases that remain to be described. This manuscript reviews emerging data on relationships between kidney disease and urinary tract infection/colonization with JC polyomavirus (JCPyV). Recent findings Approximately 30% of the adult population sheds JCPyV in the urine. Further, urinary tract infection with one polyomavirus strain appears to inhibit secondary infections. The presence of urinary JCPyV and BK polyomavirus (BKPyV) replication were measured with polymerase chain reaction in African Americans to assess relationships with apolipoprotein L1 gene (APOL1)-associated nephropathy. Urinary JCPyV was associated with paradoxically lower rates of nephropathy in those with APOL1 high-risk genotypes. Subsequent studies revealed African Americans with JCPyV viruria had lower rates of nondiabetic nephropathy independent from APOL1. Summary Urinary tract JCPyV replication is common and associates with lower rates of nephropathy. This relationship is observed in diverse settings. Results support a host immune system that fails to eradicate nonnephropathic viruses and is also less likely to manifest renal parenchymal inflammation resulting in glomerulosclerosis.

PURPOSE:To describe the study protocol and baseline characteristics of the African Descent and Glaucoma Evaluation Study (ADAGES) III. DESIGN:Cross-sectional, case-control study. PARTICIPANTS:Three thousand two hundred sixty-six glaucoma patients and control participants without glaucoma of African or European descent were recruited from 5 study centers in different regions of the United States. METHODS:Individuals of African descent (AD) and European descent (ED) with primary open-angle glaucoma (POAG) and control participants completed a detailed demographic and medical history interview. Standardized height, weight, and blood pressure measurements were obtained. Saliva and blood samples to provide serum, plasma, DNA, and RNA were collected for standardized processing. Visual fields, stereoscopic disc photographs, and details of the ophthalmic examination were obtained and transferred to the University of California, San Diego, Data Coordinating Center for standardized processing and quality review. MAIN OUTCOME MEASURES:Participant gender, age, race, body mass index, blood pressure, history of smoking and alcohol use in POAG patients and control participants were described. Ophthalmic measures included intraocular pressure, visual field mean deviation, central corneal thickness, glaucoma medication use, or past glaucoma surgery. Ocular conditions, including diabetic retinopathy, age-related macular degeneration, and past cataract surgery, were recorded. RESULTS:The 3266 ADAGES III study participants in this report include 2146 AD POAG patients, 695 ED POAG patients, 198 AD control participants, and 227 ED control participants. The AD POAG patients and control participants were significantly younger (both, 67.4 years) than ED POAG patients and control participants (73.4 and 70.2 years, respectively). After adjusting for age, AD POAG patients had different phenotypic characteristics compared with ED POAG patients, including higher intraocular pressure, worse visual acuity and visual field mean deviation, and thinner corneas (all P < 0.001). Family history of glaucoma did not differ between AD and ED POAG patients. CONCLUSIONS:With its large sample size, extensive specimen collection, and deep phenotyping of AD and ED glaucoma patients and control participants from different regions in the United States, the ADAGES III genomics study will address gaps in our knowledge of the genetics of POAG in this high-risk population.

Dialysis-associated neurovascular injury (DANI) is a significant contributor to secondary neurologic injury for patients with acute brain injury undergoing renal replacement therapy (RRT). This manuscript reviews the multi-faceted pathophysiologic aspects of DANI and focuses on options for neuro-monitoring and RRT prescription modification to prevent DANI. We consider DANI a clinical syndrome encompassing cerebral edema, impaired cerebral blood flow, and cerebrospinal fluid metabolic alterations during RRT, all of which may lead to secondary brain injury. Neurological monitoring in dialysis, particularly non-invasive methods such as near-infrared spectroscopy and transcranial Doppler ultrasonography, are emerging tools for dialysis medicine in acute brain injury and DANI prevention. Treatment options such as dialysate sodium modeling, limited solute clearance, weight-based ultrafiltration rates, cooled dialysate, and combination ultrafiltration and dialysis treatments may be helpful in limiting secondary neurologic injury from DANI. This manuscript is intended to inform neurocritical care providers about components of DANI pathophysiology, and potential preventative and treatment strategies for at-risk patients.

Relative to European Americans, African Americans have lower 25-hydroxyvitamin D (25OHD) and vitamin D binding protein (VDBP) concentrations, higher 1,25-dihydroxyvitamin D (1,25(OH)2D3) concentrations and bone mineral density (BMD), and paradoxically reduced burdens of calcified atherosclerotic plaque (subclinical atherosclerosis). To identify genetic factors contributing to vitamin D and BMD measures, association analysis of >14M variants was conducted in a maximum of 697 African American-Diabetes Heart Study participants with type 2 diabetes (T2D). The most significant association signals were detected for VDBP on chromosome 4; variants rs7041 (β = 0.44, SE = 0.019, P = 9.4x10-86) and rs4588 (β = 0.17, SE = 0.021, P = 3.5x10-08) in the group-specific component (vitamin D binding protein) gene (GC). These variants were found to be independently associated. In addition, rs7041 was also associated with bioavailable vitamin D (BAVD; β = 0.16, SE = 0.02, P = 3.3x10-19). Six rare variants were significantly associated with 25OHD, including a non-synonymous variant in HSPG2 (rs116788687; β = -1.07, SE = 0.17, P = 2.2x10-10) and an intronic variant in TNIK (rs143555701; β = -1.01, SE = 0.18, P = 9.0x10-10), both biologically related to bone development. Variants associated with 25OHD failed to replicate in African Americans from the Insulin Resistance Atherosclerosis Family Study (IRASFS). Evaluation of vitamin D metabolism and bone mineral density phenotypes in an African American population enriched for T2D could provide insight into ethnic specific differences in vitamin D metabolism and bone mineral density.

Type 2 diabetes is increasing in all ancestry groups1. Part of its genetic basis may reside among the rare (minor allele frequency 2. We analyzed high-coverage (mean depth 38.2x) whole genome sequencing from 9,639 individuals with T2D and 34,994 controls in the NHLBI’s Trans-Omics for Precision Medicine (TOPMed) program2 to show that rare, non-coding variants that are poorly captured by genotyping arrays or imputation panels contribute h2=53% (P=4.2×10−5) to the genetic component of risk in the largest (European) ancestry subset. We coupled sequence variation with islet epigenomic signatures3 to annotate and group rare variants with respect to gene expression4, chromatin state5 and three-dimensional chromatin architecture6, and show that pancreatic islet regulatory elements contribute to T2D genetic risk (h2=8%, P=2.4×10−3). We used islet annotation to create a non-coding framework for rare variant aggregation testing. This approach identified five loci containing rare alleles in islet regulatory elements that suggest novel biological mechanisms readily linked to hypotheses about variant-to-function. Large scale whole genome sequence analysis reveals the substantial contribution of rare, non-coding variation to the genetic architecture of T2D and highlights the value of tissue-specific regulatory annotation for variant-to-function discovery.

OBJECTIVES: Optimizing care for patients with advanced kidney disease requires close collaboration between primary care physicians (PCPs) and nephrologists. Factors associated with PCP referral to nephrology were assessed in patients with estimated glomerular filtration rates (eGFRs) less than 30 mL/min/1.73 m(2). STUDY DESIGN: Electronic health record review at an integrated health care network. METHODS: Factors associated with referral status were identified using Fisher’s exact tests, t tests, and multivariable logistic regression. RESULTS: Of 133,913 patients regularly seeing PCPs between October 2017 and September 2019, 1119 had a final eGFR less than 30 mL/min/1.73 m(2) and were not on renal replacement therapy. Care was provided by 185 PCPs (61 practices). Analyses were restricted to the 97.1% (n = 1087) of patients who were African American or European American. Of these, 54.6% had not been referred to nephrology. Nonreferred patients had higher numbers of PCP visits (P = .004). In contrast, referred patients were younger, were more often African American, and had PCPs at the academic medical center (all P

We assembled an ancestrally diverse collection of genome-wide association studies of type 2 diabetes (T2D) in 180,834 cases and 1,159,055 controls (48.9% non-European descent). We identified 277 loci at genome-wide significance (p-8), including 237 attaining a more stringent trans-ancestry threshold (p-9), which were delineated to 338 distinct association signals. Trans-ancestry meta-regression offered substantial enhancements to fine-mapping, with 58.6% of associations more precisely localised due to population diversity, and 54.4% of signals resolved to a single variant with >50% posterior probability. This improved fine-mapping enabled systematic assessment of candidate causal genes and molecular mechanisms through which T2D associations are mediated, laying foundations for functional investigations. Trans-ancestry genetic risk scores enhanced transferability across diverse populations, providing a step towards more effective clinical translation to improve global health.

Autosomal genetic analyses of blood lipids have yielded key insights for coronary heart disease (CHD). However, X chromosome genetic variation is understudied for blood lipids in large sample sizes. We now analyze genetic and blood lipid data in a high-coverage whole X chromosome sequencing study of 65,322 multi-ancestry participants and perform replication among 456,893 European participants. Common alleles on chromosome Xq23 are strongly associated with reduced total cholesterol, LDL cholesterol, and triglycerides (min P = 8.5 × 10−72), with similar effects for males and females. Chromosome Xq23 lipid-lowering alleles are associated with reduced odds for CHD among 42,545 cases and 591,247 controls (P = 1.7 × 10−4), and reduced odds for diabetes mellitus type 2 among 54,095 cases and 573,885 controls (P = 1.4 × 10−5). Although we observe an association with increased BMI, waist-to-hip ratio adjusted for BMI is reduced, bioimpedance analyses indicate increased gluteofemoral fat, and abdominal MRI analyses indicate reduced visceral adiposity. Co-localization analyses strongly correlate increased CHRDL1 gene expression, particularly in adipose tissue, with reduced concentrations of blood lipids., The influence of X chromosome genetic variation on blood lipids and coronary heart disease (CHD) is not well understood. Here, the authors analyse X chromosome sequencing data across 65,322 multi-ancestry individuals, identifying associations of the Xq23 locus with lipid changes and reduced risk of CHD and diabetes mellitus.

PURPOSE OF REVIEW: This review focuses on the relationships between diabetes, cognitive impairment and the contribution of kidney disease. RECENT FINDINGS: We review the independent contributions of parameters of kidney disease, including albuminuria, glomerular filtration, bone/mineral metabolism and vitamin D synthesis, on cognitive performance in patients with diabetes. Potential pathophysiologic mechanisms underlying these associations are discussed highlighting gaps in existing knowledge. Finally, effects of the dialysis procedure on the brain and cognitive performance are considered. Emphasis is placed on novel non-invasive screening tools with the potential to preserve cerebral perfusion during hemodialysis and limit cognitive decline in patients with diabetic ESKD. SUMMARY: Patients with type 2 diabetes and advanced chronic kidney disease suffer a higher prevalence of cognitive impairment. This is particularly true in patients with diabetes and end-stage kidney disease (ESKD).

The size of the human head is determined by growth in the first years of life, while the rest of the body typically grows until early adulthood1. Such complex developmental processes are regulated by various genes and growth pathways2. Rare genetic syndromes have revealed genes that affect head size3, but the genetic drivers of variation in head size within the general population remain largely unknown. To elucidate biological pathways underlying the growth of the human head, we performed the largest genome-wide association study on human head size to date (N = 79,107). We identified 67 genetic loci, 50 of which are novel, and found that these loci are preferentially associated with head size and mostly independent from height. In subsequent neuroimaging analyses, the majority of genetic variants demonstrated widespread effects on the brain, whereas the effects of 17 variants could be localized to one or two specific brain regions. Through hypothesis-free approaches, we find a strong overlap of head size variants with both cancer pathways and cancer genes. Gene set analyses showed enrichment for different types of cancer and the p53, Wnt and ErbB signalling pathway. Genes overlapping or close to lead variants – such as TP53, PTEN and APC – were enriched for genes involved in macrocephaly syndromes (up to 37-fold) and high-fidelity cancer genes (up to 9-fold), whereas this enrichment was not seen for human height variants. This indicates that genes regulating early brain and cranial growth are associated with a propensity to neoplasia later in life, irrespective of height. Our results warrant further investigations of the link between head size and cancer, as well as its clinical implications in the general population.

Introduction APOL1 G1 and G2 nephropathy-risk variants cause mitochondrial dysfunction and contribute to kidney disease. Analyses were performed to determine the genetic regulation of APOL1 and elucidate potential mechanisms in APOL1-nephropathy. Methods A global gene expression analysis was performed in human primary renal tubule cell lines derived from 50 African American individuals. Follow-up gene knock out, cell-based rescue, and microscopy experiments were performed. Results APOL1 genotypes did not alter APOL1 expression levels in the global gene expression analysis. Expression quantitative trait locus (eQTL) analysis in polyinosinic-polycytidylic acid (poly IC)–stimulated renal tubule cells revealed that single nucleotide polymorphism (SNP) rs513349 adjacent to BAK1 was a trans eQTL for APOL1 and a cis eQTL for BAK1; APOL1 and BAK1 were co-expressed in cells. BAK1 knockout in a human podocyte cell line resulted in diminished APOL1 protein, supporting a pivotal effect for BAK1 on APOL1 expression. Because BAK1 is involved in mitochondrial dynamics, mitochondrial morphology was examined in primary renal tubule cells and HEK293 Tet-on cells of various APOL1 genotypes. Mitochondria in APOL1 wild-type (G0G0) tubule cells maintained elongated morphology when stimulated by low-dose poly IC, whereas those with G1G1, G2G2, and G1G2 genotypes appeared to fragment. HEK293 Tet-on cells overexpressing APOL1 G0, G1, and G2 were created; G0 cells appeared to promote mitochondrial fusion, whereas G1 and G2 induced mitochondrial fission. The mitochondrial dynamic regulator Mdivi-1 significantly preserved cell viability and mitochondrial cristae structure and reversed mitochondrial fission induced by overexpression of G1 and G2. Conclusion Results suggest the mitochondrial fusion/fission pathway may be a therapeutic target in APOL1-nephropathy., Graphical abstract

Background Although older adults encompass almost half of patients with advanced chronic kidney disease, it remains unclear which long-term hemodialysis vascular access type, arteriovenous fistula or arteriovenous graft, is optimal with respect to effectiveness and patient satisfaction. Clinical outcomes based on the initial AV access type have not been evaluated in randomized controlled trials. This pilot study tested the feasibility of randomizing older adults with advanced kidney disease to initial arteriovenous fistula versus graft vascular access surgery. Methods Patients 65 years or older with pre-dialysis chronic kidney disease or incident end-stage kidney disease and no prior arteriovenous vascular access intervention were randomized in a 1:1 ratio to undergo surgical placement of a fistula or a graft after providing informed consent. Trial feasibility was evaluated as (i) recruitment of ≥ 70% of eligible participants, (ii) ≥ 50 to 70% of participants undergo placement of index arteriovenous access within 90 to 180 days of enrollment, respectively, (iii) ≥ 80% adherence to study-related assessments, and (iv) ≥ 70% of participants who underwent index arteriovenous access placement will have a follow-up duration of ≥ 12 months after index surgery date. Results Between September 2018 and October 2019, 81% (44/54) of eligible participants consented and were enrolled in the study; 11 had pre-dialysis chronic kidney disease, and 33 had incident or prevalent end-stage kidney disease. After randomization, 100% (21/21) assigned to arteriovenous fistula surgery and 78% (18/23) assigned to arteriovenous graft surgery underwent index arteriovenous access placement within a median (1st, 3rd quartile) of 5.0 (1.0, 14.0) days and 13.0 (5.0, 44.3) days, respectively, after referral to vascular surgery. The completion rates for study-specific assessments ranged between 40.0 and 88.6%. At median follow-up of 215.0 days, 5 participants expired, 7 completed 12 months of follow-up, and 29 are actively being followed. Assessments of grip strength, functional independence, and vascular access satisfaction were completed by > 85% of patients who reached pre-specified post-operative assessment time point. Conclusions Results from this study reveal it is feasible to enroll and randomize older adults with advanced kidney disease to one of two different arteriovenous vascular access placement surgeries. The study can progress with minor protocol adjustments to a multisite clinical trial. Trial registration Clinical Trials ID, NCT03545113.

Two renal-risk variants in the apolipoprotein L1 gene (APOL1) in African American (AA) deceased donors (DD) are associated with shorter renal allograft survival after transplantation. To identify additional genes contributing to allograft survival, a genome-wide association study was performed in 532 AA DDs. Phenotypic data were obtained from the Scientific Registry of Transplant Recipients. Association and single-nucleotide polymorphism (SNP)-by-APOL1 interaction tests were conducted using death-censored renal allograft survival accounting for relevant covariates. Replication and inverse-variance-weighted meta-analysis were performed using data from 250 AA DD in the Genomics of Transplantation study. Accounting for APOL1, multiple SNPs near the Nudix Hydrolase 7 gene (NUDT7) showed strong independent effects (P = 1.6 × 10(−8)−2.2 × 10(−8)). Several SNPs in the Translocation protein SEC63 homolog (SEC63; P = 2 × 10(−9)-3.7 × 10(−8)) and plasmacytoma variant translocation 1 (PVT1) genes (P = 4.0 × 10(−8)-7 × 10(−8)) modified the effect of APOL1 on allograft survival. SEC63 is expressed in human renal tubule cells and glomeruli, and PVT1 is associated with diabetic kidney disease. Overall, associations were detected for 41 SNPs (P = 2 × 10(−9)-5 × 10(−8)) contributing independently or interacting with APOL1 to impact renal allograft survival after transplantation from AA DD. Given the small sample size of the discovery and replication sets, independent validations and functional genomic efforts are needed to validate these results.

Background: Kidney tubular atrophy on biopsy is a strong predictor of chronic kidney disease (CKD) progression, but tubular health is poorly quantified by traditional measures including estimated glomerular filtration rate (eGFR) and albuminuria. We hypothesized that urinary biomarkers of impaired tubule function would be associated with faster eGFR declines in persons with CKD. Methods: We measured baseline urine concentrations of uromodulin, β2-microglobulin (β2m), and α1-microglobulin (α1m) among 2,428 participants of the Systolic Blood Pressure Intervention Trial with an eGFR 2. We used linear mixed models to evaluate biomarker associations with annualized relative change in eGFR, stratified by randomization arm. Results: At baseline, the mean age was 73 ± 9 years and eGFR was 46 ± 11 mL/min/1.73 m2. In the standard blood pressure treatment arm, each 2-fold higher urinary uromodulin was associated with slower % annual eGFR decline (0.34 [95% CI: 0.08, 0.60]), whereas higher urinary β2m was associated with faster % annual eGFR decline (−0.10 [95% CI: −0.18, −0.02]) in multivariable-adjusted models including baseline eGFR and albuminuria. Associations were weaker and did not reach statistical significance in the intensive blood pressure treatment arm for either uromodulin (0.11 [−0.13, 0.35], p value for interaction by treatment arm = 0.045) or β2m (−0.01 [−0.08, 0.08], p value for interaction = 0.001). Urinary α1m was not independently associated with eGFR decline in the standard (0.01 [−0.22, 0.23]) or intensive (0.03 [−0.20, 0.25]) arm. Conclusions: Among trial participants with hypertension and CKD, baseline measures of tubular function were associated with subsequent declines in kidney function, although these associations were diminished by intensive blood pressure control.

Background: The prevalence of chronic kidney disease (CKD) in African Americans (AAs) is high. Although ancestry-specific biomarkers have been identified, few translate to the clinic. Metabolomic studies may identify novel biomarkers useful for prevention, diagnosis and treatment. Methods: Plasma from 300 AA Hypertension Genetic Epidemiology Network (HyperGEN) study participants age ≥40 years with serum creatinine (SCr) ® ). SCr was measured using a thin-film adaptation of the amidohydrolase enzymatic method on fasting blood samples. Each metabolite was tested for normality and a rank-based inverse normal transformation was performed as appropriate. Multivariable linear regression was used to test for association between the metabolite (outcome) and SCr (exposure of interest) adjusting for age, gender, waist circumference and center. A Bonferroni correction was used to adjust for multiple testing using. The top 25 most significant metabolites were evaluated for replication in 367 participants from the African American-Diabetes Heart Study (AA-DHS). An exploratory pathway analysis was conducted among significant (p< 6.0*10 -5 6.0e -5 metabolites in HyperGEN. Results: Among 300 participants from HyperGEN the mean age was 54.5 years (SD=9.5) and 58.7% were female. Mean SCr was 0.93 (SD=0.25). Eighty percent were treated for hypertension and 28% had diabetes. A total of 809 metabolites were annotated in HyperGEN samples. Of those, 391 were associated with SCr at p-5 ). The top SCr associated metabolites were tartonate(hydroxymalonate)(β[SE]= 2.99[0.07], p=3.98e -117 ), 1-stearoyl-GPC(18:0)(β[SE]= 2.49[0.14], p=2.28e -44 ), 2S-3R-dihydroxybutyrate)(β[SE]= 2.36[0.14],p=1.53e -40 ) and isovalerate(C5)( β[SE]= 2.30[0.15], p = 2.78e -36 ). The association of these metabolites with SCr replicated in AA-DHS [(tartonate(hydroxymalonate)(β[SE]= 0.66[0.19], p=0.001), 1-stearoyl-GPC(18:0)(β[SE]= 1.30[0.20], p=1.61 -10 ), 2S-3R-dihydroxybutyrate)(β[SE]= 1.20[0.18],p=4.69e -11 ) and isovalerate(C5)( β[SE]= 1.24[0.20], p = 1.91e -09 )]. An exploratory pathway analysis highlighted xenobiotics and the lysophospholipid pathway. Significance: Tartronate is a xenobiotic that is related to BMI, insulin resistance and adiponectin. 1-stearoyl-GPC (18:0) is a lysophospholipid metabolite found to be associated with oxidative stress. Conclusion: The current study discovered and replicated metabolites associated with SCr in a population of AAs with a high prevalence of hypertension. If validated, these could provide new insights in kidney disease pathways or aid in the treatment and prevention of CKD in the AA population.