Physical function and mortality in older adults with chronic kidney disease.

BACKGROUND: Accurate mortality prediction can guide clinical care for older adults with chronic kidney disease (CKD). Yet existing tools do not incorporate physical function, an independent predictor of death in older adults. We determined whether incorporating physical function measurements improve mortality prediction among older adults with CKD. METHODS: We included Chronic Renal Insufficiency Cohort participants who were ≥65 years old, had estimated Glomerular Filtration Rate (eGFR) <60 mL/min/1.73m2, not receiving kidney failure replacement therapy (KFRT), and had least one gait speed assessment. Gait speed was measured at usual pace (≥0.84, 0.83-0.65, 0.64-0.47, ≤0.46 meters/second, or unable), and frailty was assessed using Physical Frailty Phenotype criteria (range 0 to 5 points, also known as Fried criteria). We modeled time to all-cause death over five years using Cox proportional hazard models, treating KFRT as censored and non-censored events in separate analyses. C-statistics assessed model discrimination. RESULTS: Among 2,338 persons, mean age was 70±4 years; 43% were female and 43% were Black. Mean eGFR was 42±13 mL/min/1.73m2 and median urine albumin-to-creatinine ratio was 33 mg/g [Q1 9, Q3 206]. Over a median follow-period of 5 years, 392 died and 164 developed KFRT. In censored analyses, adding gait speed or frailty improved mortality risk prediction. The C-statistic changed from 0.69 to 0.72 with gait speed scores, and from 0.70 to 0.73 with frailty scores. The performance of models with gait speed or frailty was similar in non-censored analyses. CONCLUSION: Among older adults with CKD, adding measures of physical function modestly improves mortality prediction.

Characterizing the Impact of the Covid-19 Pandemic on Adults with Autosomal Dominant Polycystic Kidney Disease: A Cross-Sectional Study.

Background: The Covid-19 pandemic greatly affected those with chronic diseases, impacting healthcare access and healthcare seeking behaviors. The impact of the pandemic on adults with Autosomal Dominant Polycystic Kidney Disease (ADPKD) has not been investigated. Methods: Participants were recruited from a cohort of 239 ADPKD patients enrolled in a longitudinal study at the University of Maryland. Patients on renal replacement therapy were excluded. N = 66 patients participated in a phone questionnaire from June 2022-December 2022 about ADPKD-related complications, concern about contracting Covid-19, healthcare-seeking behaviors, and telehealth utilization before and after March 2020. Results: N = 34 (51.5%) of participants reported a positive Covid-19 test result and N = 29 (44%) expressed high concern of contracting Covid-19. Those who avoided medical care at least once (N = 17, 25.8%) had similar demographics and ADPKD severity to those who did not, but reported greater telehealth utilization (88.2% vs. 42.9%, p = 0.002), greater use of non-prescribed medication for Covid-19 treatment or prevention (35.3% vs. 8.2%, p = 0.01), and were more likely to contract Covid-19 (76.5% vs. 42.9%, p = 0.02). Among the N = 53 who reported very good or excellent ADPKD disease management pre-pandemic, N = 47(89%) reported no significant change during the pandemic. Conclusions: In this highly educated, high-income cohort with a mean age of 46.1 years, most people reported well-managed ADPKD prior to the pandemic. This may explain why less than half of participants expressed high concern for contracting Covid-19. Overall, there was no significant pandemic-related decline in self-reported ADPKD management, like due to excellent access to, and uptake of, telehealth services. Notably, 1 in 4 participants reported healthcare avoidant behavior, the effect of which may only be seen years from now. Future studies should investigate potential impacts of avoidant behaviors, as well as expand investigation to a more diverse cohort whose care may not have been as easily transitioned to telehealth.

Mortality risk in patients with autosomal dominant polycystic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the leading inheritable cause of end-stage renal disease (ESRD). Mortality data specific to patients with ADPKD is currently lacking; thus, the aim of this study was to estimate mortality in patients with ADPKD. METHODS: We analyzed data from the United States Renal Data System (USRDS) for patients with ADPKD available during the study period of 01/01/2014-12/31/2016, which included a cohort of patients with non-ESRD chronic kidney disease (CKD) and a cohort of patients with ESRD. Mortality rates with 95% confidence intervals (CIs) were calculated overall and by age group, sex, and race for the full dataset and for a subset of patients aged ≥ 65 years. Adjusted mortality hazard ratios (HRs) were calculated using Cox regression modeling by age group, sex, race, and CKD stage (i.e., non-ESRD CKD stages 1-5) or ESRD treatment (i.e., dialysis and transplant). RESULTS: A total of 1,936 patients with ADPKD and non-ESRD CKD and 37,461 patients with ADPKD and ESRD were included in the analysis. Age-adjusted mortality was 18.4 deaths per 1,000 patient-years in the non-ESRD CKD cohort and 37.4 deaths per 1,000 patient-years in the ESRD cohort. As expected, among the non-ESRD CKD cohort, patients in CKD stages 4 and 5 had a higher risk of death than patients in stage 3 (HR = 1.59 for stage 4 and HR = 2.71 for stage 5). Among the ESRD cohort, patients receiving dialysis were more likely to experience death than patients who received transplant (HR = 2.36). Age-adjusted mortality among patients aged ≥ 65 years in the non-ESRD CKD cohort was highest for Black patients (82.7 deaths per 1,000 patient-years), whereas age-adjusted mortality among patients aged ≥ 65 years in the ESRD cohort was highest for White patients (136.1 deaths per 1,000 patient-years). CONCLUSIONS: Mortality rates specific to patients aged ≥ 65 years suggest racial differences in mortality among these patients in both non-ESRD CKD and ESRD cohorts. These data fill an important knowledge gap in mortality estimates for patients with ADPKD in the United States.

Association of Continued Use of SGLT2 Inhibitors From the Ambulatory to Inpatient Setting With Hospital Outcomes in Patients With Diabetes: A Nationwide Cohort Study.

OBJECTIVE: Limited data are available on the continuation of outpatient sodium glucose cotransporter 2 inhibitors (SGLT2is) during hospitalization. The objective was to evaluate associations of SGLT2i continuation in the inpatient setting with hospital outcomes. RESEARCH DESIGN AND METHODS: This nationwide cohort study used Veterans Affairs health care system data of acute care hospitalizations between 1 April 2013 and 31 August 2021. A total of 36,505 admissions of patients with diabetes with an outpatient prescription for an SGLT2i prior to hospitalization were included. The exposure was defined as SGLT2i continuation during hospitalization. Admissions where SGLT2i was continued were compared with admissions where it was discontinued. The primary outcome was in-hospital mortality. Secondary outcomes were acute kidney injury (AKI) and length of stay (LOS). Negative binomial propensity score-weighted and zero-truncated analyses were used to compare outcomes and adjusted for multiple covariates, including demographics and comorbidities. RESULTS: Mean (SE) age was 67.2 (0.1) and 67.5 (0.1) years (P = 0.03), 97.0% and 96.6% were male (P = 0.1), 71.3% and 72.1% White, and 20.8% and 20.5% Black (P = 0.52) for the SGLT2i continued and discontinued groups, respectively. After adjustment for covariates (age, sex, race, BMI, Elixhauser Comorbidity Index, procedures/surgeries, and insulin use), the SGLT2i continued group had a 45% lower mortality rate (incidence rate ratio [IRR] 0.55, 95% CI 0.42-0.73, P < 0.01), no difference in AKI (IRR 0.96, 95% CI 0.90-1.02, P = 0.17), and decreased LOS (4.7 vs. 4.9 days) (IRR 0.95, 95% CI 0.93-0.98, P < 0.01) versus the SGLT2i discontinued group. Similar associations were observed across multiple sensitivity analyses. CONCLUSIONS: Continued SGLT2i during hospitalization among patients with diabetes was associated with lower mortality, no increased AKI, and shorter LOS.

Electrocardiographic Associations of Cardiac Biomarkers and Cardiac Magnetic Resonance Measures of Fibrosis in the Multiethnic Study of Atherosclerosis (MESA).

Abnormalities in myocardial substrate, including diffuse and replacement fibrosis, increase the risk of cardiovascular disease (CVD). Data are sparse on whether electrocardiogram (ECG) measures, coupled with circulating biomarkers, may aid in identifying cardiac fibrosis. This study aimed to determine whether 12-lead ECG and biomarkers together augment the prediction of cardiac fibrosis in participants who are free of known CVD. This is a cross-sectional analysis in the MESA (Multiethnic Study of Atherosclerosis) study at visit 5 (2010 to 2012), with measurements of biomarkers (cardiac troponin T and growth differentiation factor-15), gadolinium-enhanced cardiac magnetic resonance imaging, and ECG. Logistic regression associations of ECG measures with cardiac magnetic resonance surrogates of fibrosis (highest quartile extracellular volume [interstitial fibrosis] and late gadolinium enhancement [replacement fibrosis]) were adjusted for demographics and risk factors. Using the C-statistic, we evaluated whether adding ECG measures and biomarkers to clinical characteristics improved the prediction of either type of fibrosis. There were 1,170 eligible participants (aged 67.1 ± 8.6 years). Among the ECG measures, QRS duration (odds ratio [OR] 1.41 per 10 ms, 95% confidence interval [CI] 1.10 to 1.81), major ST-T abnormalities (OR 3.03, 95%CI 1.20, 7.65), and abnormal QRS-T angle (OR 6.32, 95%CI 3.00, 13.33) were associated with replacement fibrosis, whereas only abnormal QRS-T angle (OR 3.05, 95%CI,1.69, 5.48) was associated with interstitial fibrosis. ECG markers, in addition to clinical characteristics, improved the prediction of replacement fibrosis (p = 0.002) but not interstitial fibrosis. The addition of cardiac troponin T and growth differentiation factor-15 to the ECG findings did not significantly improve the model discrimination for either type of cardiac fibrosis. In CVD free participants, simple ECG measures are associated with replacement fibrosis and interstitial fibrosis. The addition of these measures improves identification of replacement but not interstitial fibrosis. These findings may help refine the identification of myocardial scar in the general population.

Plasma neurofilament light and brain volumetric outcomes among middle-aged urban adults.

Elevated plasma neurofilament light chain (NfL) is associated with dementia though underlying mechanisms remain unknown. We examined cross-sectional relationships of time-dependent plasma NfL with selected brain structural magnetic resonance imaging (sMRI) prognostic markers of dementia. The sample was drawn from the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study, selecting participants with complete v1 (2004-2009) and v2 (2009-2013) plasma NfL exposure and ancillary sMRI data at vscan (2011-2015, n = 179, mean v1 to vscan time: 5.4 years). Multivariable-adjusted linear regression models were conducted, overall, by sex, and race, correcting for multiple testing with q-values. NfL(v1) was associated with larger WMLV (both Loge transformed), after 5-6 years' follow-up, overall (ß = +2.131 ± 0.660, b = +0.29, p = 0.001, and q = 0.0029) and among females. NfLv2 was linked to a 125 mm3 lower left hippocampal volume (p = 0.004 and q = 0.015) in reduced models, mainly among males, as was observed for annualized longitudinal change in NfL (δNfLbayes). Among African American adults, NfLv1 was inversely related to total, gray and white matter volumes. Plasma NfL may reflect future brain pathologies in middle-aged adults.

Association between proteomic biomarkers and myocardial fibrosis measured by MRI: the multi-ethnic study of atherosclerosis.

BACKGROUND: Cardiac magnetic resonance imaging (CMR) determines the extent of interstitial fibrosis, measured by increased extracellular volume (ECV), and replacement fibrosis with late gadolinium myocardial enhancement (LGE). Despite advances in detection, the pathophysiology of subclinical myocardial fibrosis is incompletely understood. Targeted proteomic discovery technologies enable quantification of low abundance circulating proteins to elucidate cardiac fibrosis mechanisms. METHODS: Using a cross-sectional design, we selected 92 LGE+ cases and 92 LGE- demographically matched controls from the Multi-Ethnic Study of Atherosclerosis. Similarly, we selected 156 cases from the highest ECV quartile and matched with 156 cases from the lowest quartile. The plasma serum proteome was analyzed using proximity extension assays to determine differential regulation of 92 proteins previously implicated with cardiovascular disease. Results were analyzed using volcano plots of statistical significance vs. magnitude of change and Bayesian additive regression tree (BART) models to determine importance. FINDINGS: After adjusting for false discovery, higher ECV was significantly associated with 17 proteins. Using BART, Plasminogen activator inhibitor 1, Insulin-like growth factor-binding protein 1, and N-terminal pro-B-type natriuretic peptide were associated with higher ECV after accounting for other proteins and traditional cardiovascular risk factors. In contrast, no circulating proteins were associated with replacement fibrosis. INTERPRETATIONS: Our results suggest unique circulating proteomic signatures associated with interstitial fibrosis emphasizing its systemic influences. With future validation, protein panels may identify patients who may develop interstitial fibrosis with progression to heart failure. FUNDING: This research was supported by contracts and grants from NHLBI, NCATS and the Inova Heart and Vascular Institute.

Association of Longitudinal Urinary Metabolic Biomarkers With ADPKD Severity and Response to Metformin in TAME-PKD Clinical Trial Participants.

Introduction: Dysregulated cellular metabolism contributes to autosomal dominant polycystic kidney disease (ADPKD) pathogenesis. The Trial of Administration of Metformin in Polycystic Kidney Disease (TAME-PKD) tested the effects of metformin treatment over 2 years in adult ADPKD patients with mild-moderate disease severity. Metformin was found to be safe and tolerable with an insignificant trend toward reduced estimated glomerular filtration rate (eGFR) decline compared to placebo. Here we tested whether targeted urinary metabolic biomarkers measured in TAME-PKD participants correlated with disease progression, severity, and metformin treatment in cross-sectional and longitudinal analyses. Methods: Concentrations of total protein, targeted metabolites (lactate, pyruvate, and succinate), and glycolytic enzymes (pyruvate kinase-M2, lactate dehydrogenase-A, and pyruvate dehydrogenase kinase-1) were measured and normalized by creatinine or osmolality in urine specimens and compared with height-adjusted total kidney volume (htTKV) and eGFR at the different study timepoints. Results: In cross-sectional analyses utilizing placebo group data, urinary succinate normalized by creatinine negatively correlated with ln (htTKV), whereas protein excretion strongly positively correlated with ln (htTKV), and negatively correlated with eGFR. Significant time-varying negative associations occurred with eGFR and the lactate/pyruvate ratio and with urine protein normalized by osmolality, indicating correlations of these biomarkers with disease progression. In secondary analyses, urinary pyruvate normalized by osmolality was preserved in metformin-treated participants but declined in placebo over the 2-year study period with a significant between-arm difference, suggesting time-dependent urinary pyruvate changes may serve as a discriminator for metformin treatment effects in this study population. Conclusion: Proteinuria with enhanced glycolytic and reduced oxidative metabolic markers generally correlated with disease severity and risk of progression in the TAME-PKD study population.

Association of cardiac troponin T and growth differentiation factor 15 with replacement and interstitial cardiac fibrosis in community dwelling adults: The multi-ethnic study of atherosclerosis.

Background: Subclinical abnormalities in myocardial structure (stage B heart failure) may be identified by cardiac and non-organ specific biomarkers. The associations of high-sensitivity cardiac troponin T (hs-cTnT) and growth differentiation factor-15 (GDF-15) with cardiac magnetic resonance imaging (CMR) interstitial fibrosis (extracellular volume [ECV]) is unknown and for GDF-15 the association with replacement (late gadolinium enhancement [LGE]) is also unknown. GDF-15 is a systemic biomarker also released by myocytes associated with fibrosis and inflammation. We sought to define the associations of hs-cTnT and GDF-15 with these CMR fibrosis measures in the MESA cohort. Methods: We measured hs-cTnT and GDF-15 in MESA participants free of cardiovascular disease at exam 5. CMR measurements were complete in 1737 for LGE and 1258 for ECV assessment. We estimated the association of each biomarker with LGE and increased ECV (4th quartile) using logistic regression, adjusted for demographics and risk factors. Results: Mean age of the participants was 68 ± 9 years. Unadjusted, both biomarkers were associated with LGE, but after adjustment only hs-cTnT concentrations remained significant (4th vs. 1st quartile OR] 7.5, 95% CI: 2.1, 26.6). For interstitial fibrosis both biomarkers were associated with 4th quartile ECV, but the association was attenuated compared to replacement fibrosis. After adjustment, only hs-cTnT concentrations remained significant (1st to 4th quartile OR 1.7, 95%CI: 1.1, 2.8). Conclusion: Our findings identify that both interstitial and replacement fibrosis are associated with myocyte cell death/injury, but GDF-15 a non-organ specific biomarker prognostic for incident cardiovascular disease is not associated with preclinical evidence of cardiac fibrosis.

Assessment of Biomarkers of Myocardial injury, Inflammation, and Renal Function in Heart Failure With Reduced Ejection Fraction: The VICTORIA Biomarker Substudy.

BACKGROUND: Circulating biomarkers may be useful in understanding prognosis and treatment efficacy in heart failure with reduced ejection fraction. In the VICTORIA (Vericiguat Global Study in Subjects with Heart Failure with Reduced Ejection Fraction) trial, vericiguat, a soluble guanylate cyclase stimulator, decreased the primary outcome of cardiovascular death or heart failure hospitalization in heart failure with reduced ejection fraction. We evaluated biomarkers of cardiac injury, inflammation, and renal function for associations with outcomes and vericiguat treatment effect. METHODS AND RESULTS: High-sensitivity cardiac troponin T (hs-cTnT), growth differentiation factor-15 (GDF-15), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), and cystatin C were measured at baseline and 16 weeks. Associations of biomarkers with the primary outcome and its components were estimated. Interaction with study treatment was tested. Changes in biomarkers over time were examined by study treatment. One or more biomarkers were measured in 4652 (92%) of 5050 participants at baseline and 4063 (81%) at 16 weeks. After adjustment, higher values of hs-cTnT, growth differentiation factor-15, and interleukin-6 were associated with the primary outcome, independent of N-terminal pro-B-type natriuretic peptide. Higher hs-cTnT values were associated with a hazard ratio per log standard deviation of 1.21 (95% confidence interval 1.14-1.27). A treatment interaction with vericiguat was evident with hs-cTnT and cardiovascular death (P = .04), but not HF hospitalization (P = .38). All biomarkers except cystatin C decreased over 16 weeks and no relationship between treatment assignment and changes in biomarker levels was observed. CONCLUSIONS: hs-cTnT, growth differentiation factor-15, and interleukin-6 levels were associated with risk of the primary outcome in VICTORIA (Vericiguat Global Study in Subjects with Heart Failure with Reduced Ejection Fraction). Uniquely, lower hs-cTnT was associated with a lower rate of cardiovascular death but not HF hospitalization after treatment with vericiguat.

Longitudinal Changes in Cardiac Troponin and Risk of Heart Failure Among Black Adults.

BACKGROUND: Among Black adults, high-sensitivity cardiac troponin I (hs-cTnI) is associated with heart failure (HF) risk. The association of longitudinal changes in hs-cTnI with risk of incident HF, HF with reduced and preserved ejection fraction (HFrEF and HFpEF, respectively), among Black adults is not well-established. METHODS AND RESULTS: This study included Black participants from the Jackson Heart Study with available hs-cTnI data at visits 1 (2000-2004) and 2 (2005-2008) and no history of cardiovascular disease. Cox models were used to evaluate associations of categories of longitudinal change in hs-cTnI with incident HF risk. Among 2423 participants, 11.6% had incident elevation in hs-cTnI at visit 2, and 16.9% had stable or improved elevation (≤50% increase in hs-cTnI), and 4.0% had worsened hs-cTnI elevation (>50% increase). Over a median follow-up of 12.0 years, there were 139 incident HF hospitalizations (64 HFrEF, 58 HFpEF). Compared with participants without an elevated hs-cTnI, those with incident, stable or improved, or worsened hs-cTnI elevation had higher HF risk (adjusted hazard ratio 3.20 [95% confidence interval, 1.92-5.33]; adjusted hazard ratio 2.40, [95% confidence interval, 1.47-3.92]; and adjusted hazard ratio 8.10, [95% confidence interval, 4.74-13.83], respectively). Similar patterns of association were observed for risk of HFrEF and HFpEF. CONCLUSIONS: Among Black adults, an increase in hs-cTnI levels on follow-up was associated with a higher HF risk. LAY SUMMARY: The present study included 2423 Black adults from the Jackson Heart Study with available biomarkers of cardiac injury and no history of cardiovascular disease at visits 1 and 2. The majority of participants did not have evidence of cardiac injury at both visits (67.5%), 11.6% had evidence of cardiac injury only on follow-up, 14.5% had stable elevations, 4.0% had worsened elevations, and 2.4% had improved elevations of cardiac injury biomarkers during follow-up. Compared with participants without evidence of cardiac injury, those with new, stable, and worsened levels of cardiac injury had a higher risk of developing heart failure. TWEET: Among Black adults, persistent or worsening subclinical myocardial injury is associated with an elevated risk of HF.

Effect of Long-term Exercise Training on Physical Performance and Cardiorespiratory Function in Adults With CKD: A Randomized Controlled Trial.

RATIONALE & OBJECTIVE: The safety and efficacy of long-term exercise training in reducing physical functional loss in older adults with advanced CKD and comorbidity is uncertain. STUDY DESIGN: Multicenter, parallel group, randomized controlled trial. SETTINGS & PARTICIPANTS: Adults 55 years and older with estimated glomerular filtration rate (eGFR) of 15 to <45 mL/min/1.73 m2 enrolled from centers in Baltimore and Boston. INTERVENTION: Twelve months of in-center supervised exercise training incorporating majority aerobic but also muscle strengthening activities or a group health education control intervention, randomly assigned in 1:1 ratio. OUTCOME: Primary outcomes were cardiorespiratory fitness and submaximal gait at 6 and 12 months quantified by peak oxygen consumption (Vo2peak) on graded exercise treadmill test and distance walked on the 6-minute walk test, respectively. Secondary outcomes were changes in lower extremity function, eGFR, albuminuria, glycemia, blood pressure, and body mass index. RESULTS: Among 99 participants, the mean age was 68 years, 62% were African American, and the mean eGFR was 33 mL/min/1.73 m2; 59% had diabetes, and 29% had coronary artery disease. Among those randomized to exercise, 59% of exercise sessions were attended in the initial 6 months. Exercise was well tolerated without excess occurrence of adverse events. At 6 months, aerobic capacity was higher among exercise participants (17.9 ± 5.5 vs 15.9 ± 7.0 mL/kg/min, P = 0.03), but the differences were not sustained at 12 months. The 6-minute walk distance improved more in the exercise group (adjusted difference: 98 feet [P = 0.02; P = 0.03 for treatment-by-time interaction]). The exercise group had greater improvements on the Timed Up and Go Test (P = 0.04) but not the Short Physical Performance Battery (P = 0.8). LIMITATIONS: Planned sample size was not reached. Loss to follow-up and dropout were greater than anticipated. CONCLUSIONS: Among adults aged ≥55 years with CKD stages 3b-4 and a high level of medical comorbidity, a 12-month program of in-center aerobic and resistance exercise training was safe and associated with improvements in physical functioning. FUNDING: Government grants (National Institutes of Health). TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT01462097.

Plasma neurofilament light as blood marker for poor brain white matter integrity among middle-aged urban adults.

Plasma neurofilament light chain (NfL)'s link to dementia may be mediated through white matter integrity (WMI). In this study, we examined plasma NfL's relationships with diffusion tensor magnetic resonance imaging markers: global and cortical white matter fractional anisotropy (FA) and trace (TR). Plasma NfL measurements at 2 times (v1: 2004-2009 and v2: 2009-2013) and ancillary dMRI (vscan: 2011-2015) were considered (n = 163, mean time v1 to vscan = 5.4 years and v2 to vscan: 1.1 years). Multivariable-adjusted regression models, correcting for multiple-testing revealed that, overall, higher NfLv1 was associated with greater global TR (ß ± SE: +0.0000560 ± 0.0000186, b = 0.27, p = 0.003, q = 0.012), left frontal WM TR (ß ± SE: + 0.0000706 ± 0.0000201, b ± 0.30, p = 0.001, q = 0.0093) and right frontal WM TR (ß ± SE: + 0.0000767 ± 0.000021, b ± 0.31, p < 0.001, q = 0.0093). These associations were mainly among males and White adults. Among African American adults only, NfLv2 was associated with greater left temporal lobe TR. "Tracking high" in NfL was associated with reduced left frontal FA (Model 2, body mass index-adjusted: ß ± SE:-0.01084 ± 0.00408, p = 0.009). Plasma NfL is a promising biomarker predicting future brain white matter integrity (WMI) in middle-aged adults.

White matter integrity as a mediator between socioeconomic status and executive function.

Introduction: Lower socioeconomic status (SES) is associated with poorer executive function, but the neural mechanisms of this association remain unclear. As healthy brain communication is essential to our cognitive abilities, white matter integrity may be key to understanding socioeconomic disparities. Methods: Participants were 201 African American and White adults (ages 33-72) from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) SCAN study. Diffusion tensor imaging was used to estimate regional fractional anisotropy as a measure of white matter integrity. Adjusting for age, analyses examined if integrity of the anterior limb of the internal capsule (ALIC), external capsule (EC), superior longitudinal fasciculus (SLF), and cingulum mediated SES-executive function relations. Results: Lower SES was related to poorer cognitive performance and white matter integrity. Lower Trails B performance was related to poorer integrity of the ALIC, EC, and SLF, and lower Stroop performance was associated with poorer integrity of the ALIC and EC. ALIC mediated the SES-Trails B relation, and EC mediated the SES-Trails B and SES-Stroop relations. Sensitivity analyses revealed that (1) adjustment for race rendered the EC mediations non-significant, (2) when using poverty status and continuous education as predictors, results were largely the same, (3) at least some of the study's findings may generalize to processing speed, (4) mediations are not age-dependent in our sample, and (5) more research is needed to understand the role of cardiovascular risk factors in these models. Discussion: Findings demonstrate that poorer white matter integrity helps explain SES disparities in executive function and highlight the need for further clarification of the biopsychosocial mechanisms of the SES-cognition association.

Defining cellular complexity in human autosomal dominant polycystic kidney disease by multimodal single cell analysis.

Autosomal dominant polycystic kidney disease (ADPKD) is the leading genetic cause of end stage renal disease characterized by progressive expansion of kidney cysts. To better understand the cell types and states driving ADPKD progression, we analyze eight ADPKD and five healthy human kidney samples, generating single cell multiomic atlas consisting of ~100,000 single nucleus transcriptomes and ~50,000 single nucleus epigenomes. Activation of proinflammatory, profibrotic signaling pathways are driven by proximal tubular cells with a failed repair transcriptomic signature, proinflammatory fibroblasts and collecting duct cells. We identify GPRC5A as a marker for cyst-lining collecting duct cells that exhibits increased transcription factor binding motif availability for NF-κB, TEAD, CREB and retinoic acid receptors. We identify and validate a distal enhancer regulating GPRC5A expression containing these motifs. This single cell multiomic analysis of human ADPKD reveals previously unrecognized cellular heterogeneity and provides a foundation to develop better diagnostic and therapeutic approaches.

A disease progression model estimating the benefit of tolvaptan on time to end-stage renal disease for patients with rapidly progressing autosomal dominant polycystic kidney disease.

BACKGROUND: Tolvaptan was approved in the United States in 2018 for patients with autosomal dominant polycystic kidney disease (ADPKD) at risk of rapid progression as assessed in a 3-year phase 3 clinical trial (TEMPO 3:4). An extension study (TEMPO 4:4) showed continued delay in progression at 2 years, and a trial in patients with later-stage disease (REPRISE) provided confirmatory evidence of efficacy. Given the relatively shorter-term duration of the clinical trials, estimating the longer-term benefit associated with tolvaptan via extrapolation of the treatment effect is an important undertaking. METHODS: A model was developed to simulate a cohort of patients with ADPKD at risk of rapid progression and predict their long-term outcomes using an algorithm organized around the Mayo Risk Classification system, which has five subclasses (1A through 1E) based on estimated kidney growth rates. The model base-case population represents 1280 patients enrolled in TEMPO 3:4 beginning in chronic kidney disease (CKD) stages G1, G2, and G3 across Mayo subclasses 1C, 1D, and 1E. The algorithm was used to predict longer-term natural history health outcomes. The estimated treatment effect of tolvaptan from TEMPO 3:4 was applied to the natural history to predict the longer-term treatment benefit of tolvaptan. For the cohort, analyzed once reflecting natural history and once assuming treatment with tolvaptan, the model estimated lifetime progression through CKD stages, end-stage renal disease (ESRD), and death. RESULTS: When treated with tolvaptan, the model cohort was predicted to experience a 3.1-year delay of ESRD (95% confidence interval: 1.8 to 4.4), approximately a 23% improvement over the estimated 13.7 years for patients not receiving tolvaptan. Patients beginning tolvaptan treatment in CKD stages G1, G2, and G3 were predicted to experience estimated delays of ESRD, compared with patients not receiving tolvaptan, of 3.8 years (21% improvement), 3.0 years (24% improvement), and 2.1 years (28% improvement), respectively. CONCLUSIONS: The model estimated that patients treated with tolvaptan versus no treatment spent more time in earlier CKD stages and had later onset of ESRD. Findings highlight the potential long-term value of early intervention with tolvaptan in patients at risk of rapid ADPKD progression.