Epigenetic associations with kidney disease in individuals of African ancestry with APOL1 high-risk genotypes and Human Immunodeficiency Virus.

BACKGROUND: Apolipoprotein L1 (APOL1) high-risk variants are major determinants of chronic kidney disease (CKD) in people of African ancestry. Previous studies have identified epigenetic changes in relation to kidney function and CKD, but not in individuals with APOL1 high-risk genotypes. We conducted an epigenome-wide analysis of CKD and estimated glomerular filtration rate (eGFR) in in people of African ancestry and APOL1 high-risk genotypes with HIV. METHODS: DNA methylation profiles from peripheral blood mononuclear cells of 119 individuals with APOL1 high-risk genotypes (mean age 48 years, 49% female, median CD4 count 515 cells/mm3, 90% HIV-1 RNA <200 copies/mL, 23% with CKD) were obtained by Illumina MethylationEPIC BeadChip. Differential methylation analysis of CKD considered technical and biological covariates. We also assessed associations with eGFR. Replication was pursued in three independent multi-ancestry cohorts with and without HIV. RESULTS: DNA methylation levels at 14 regions were associated with CKD. The strongest signals were located in SCARB1, DNAJC5B and C4orf50. Seven of the 14 signals also associated with eGFR, and most showed evidence for a genetic basis. Four signals (in SCARB1, FRMD4A, CSRNP1 and RAB38) replicated in other cohorts, and 11 previously reported epigenetic signals for kidney function or CKD replicated in our cohort. We found no significant DNA methylation signals in, or near, the APOL1 promoter region. CONCLUSIONS: We report several novel as well as previously reported epigenetic associations with CKD and eGFR in individuals with HIV having APOL1 high-risk genotypes. Further investigation of pathways linking DNA methylation to APOL1 nephropathies is warranted.

Twelve tips to aid interpretation of post-assessment psychometric reports.

Post-assessments psychometric reports are a vital component of the assessment cycle to ensure that assessments are reliable, valid and fair to make appropriate pass-fail decisions. Students' scores can be summarised by examination of frequency distributions, central tendency measures and dispersion measures. Item discrimination indicies to assess the quality of items, and distractors that differentiate between students achieving or not achieving the learning outcomes are key. Estimating individual item reliability and item validity indices can maximise test-score reliability and validity. Test accuracy can be evaluated by assessing test reliability, consistency and validity and standard error of measurement can be used to measure the variation. Standard setting, even by experts, may be unreliable and reality checks such as the Hofstee method, P values and correlation analysis can improve validity. The Rasch model of student ability and item difficulty assists in modifying assessment questions, pinpointing areas for additional instruction. We propose 12 tips to support test developers in interpreting structured psychometric reports, including analysis and refinement of flawed items and ensuring fair assessments with accurate and defensible marks.

Outcome and effect of vaccination in SARS-CoV-2 Omicron infection in hemodialysis patients: a cohort study.

BACKGROUND: Hemodialysis patients are at high risk of Covid-19, though vaccination has significant efficacy in preventing and reducing the severity of infection. Little information is available on disease severity and vaccine efficacy since the dissemination of the Omicron variant. METHODS: In a multi-center study, during a period of the epidemic driven by the Omicron variant, all hemodialysis patients positive for SARS-CoV-2 were identified. Outcomes were analyzed according to predictor variables including vaccination status. Risk of infection was analyzed using a Cox proportional hazards model. RESULTS: SARS-CoV-2 infection was identified in 1126 patients including 200 (18%) unvaccinated, 56 (5%) post first dose, 433 (38%) post second dose, and 437 (39%) at least 7 days beyond their third dose. The majority of patients had a mild course but 160 (14%) were hospitalized and 28 (2%) died. In regression models adjusted for age and comorbidity, two-dose vaccination was associated with a 39% (95%CI: 2%-62%) reduction in admissions, but third doses provided additional protection, with a 51% (95%CI: 25%-69%) further reduction in admissions. Among 1265 patients at risk at the start of the observation period, SARS-CoV-2 infection was observed in 211 (17%). Two-dose vaccination was associated with a 41% (95%CI: 3%-64%) reduction in the incidence of infection, with no clear additional effect provided by third doses. CONCLUSIONS: These data demonstrate lower incidence of SARS-CoV-2 infection after vaccination in dialysis patients during an Omicron dominant period of the epidemic. Among those developing infection, severe illness was less common with prior vaccination, particularly after third vaccine doses.

Stimulated phosphorylation of ERK in mouse kidney mesangial cells is dependent upon expression of Cav3.1.

BACKGROUND: T-type calcium channels (TTCC) are low voltage activated channels that are widely expressed in the heart, smooth muscle and neurons. They are known to impact on cell cycle progression in cancer and smooth muscle cells and more recently, have been implicated in rat and human mesangial cell proliferation. The aim of this study was to investigate the roles of the different isoforms of TTCC in mouse mesangial cells to establish which may be the best therapeutic target for treating mesangioproliferative kidney diseases.  METHODS: In this study, we generated single and double knockout (SKO and DKO) clones of the TTCC isoforms CaV3.1 and CaV3.2 in mouse mesangial cells using CRISPR-cas9 gene editing. The downstream signals linked to this channel activity were studied by ERK1/2 phosphorylation assays in serum, PDGF and TGF-ß1 stimulated cells. We also examined their proliferative responses in the presence of the TTCC inhibitors mibefradil and TH1177. RESULTS: We demonstrate a complete loss of ERK1/2 phosphorylation in response to multiple stimuli (serum, PDGF, TGF-ß1) in CaV3.1 SKO clone, whereas the CaV3.2 SKO clone retained these phospho-ERK1/2 responses. Stimulated cell proliferation was not profoundly impacted in either SKO clone and both clones remained sensitive to non-selective TTCC blockers, suggesting a role for more than one TTCC isoform in cell cycle progression. Deletion of both the isoforms resulted in cell death. CONCLUSION: This study confirms that TTCC are expressed in mouse mesangial cells and that they play a role in cell proliferation. Whereas the CaV3.1 isoform is required for stimulated phosphorylation of ERK1/2, the Ca V3.2 isoform is not. Our data also suggest that neither isoform is necessary for cell proliferation and that the anti-proliferative effects of mibefradil and TH1177 are not isoform-specific. These findings are consistent with data from in vivo rat mesangial proliferation Thy1 models and support the future use of genetic mouse models to test the therapeutic actions of TTCC inhibitors.

Is point-of-care testing feasible and safe in care homes in England? An exploratory usability and accuracy evaluation of a point-of-care polymerase chain reaction test for SARS-CoV-2.

INTRODUCTION: Reliable rapid testing for COVID-19 is needed in care homes to reduce the risk of outbreaks and enable timely care. This study aimed to examine the usability and test performance of a point of care polymerase chain reaction (PCR) test for detection of SARS-CoV-2 (POCKITTM Central) in care homes. METHODS: POCKITTM Central was evaluated in a purposeful sample of four UK care homes. Test agreement with laboratory real-time PCR and usability and used errors were assessed. RESULTS: No significant usability-related hazards emerged, and the sources of error identified were found to be amendable with minor changes in training or test workflow. POCKITTM Central has acceptable sensitivity and specificity based on RT-PCR as the reference standard, especially for symptomatic cases.Asymptomatic specimens showed 83.3% (95% confidence interval (CI): 35.9-99.6%) positive agreement and 98.7% negative agreement (95% CI: 96.2-99.7%), with overall prevalence and bias-adjusted kappa (PABAK) of 0.965 (95% CI: 0.932- 0.999). Symptomatic specimens showed 100% (95% CI: 2.5-100%) positive agreement and 100% negative agreement (95% CI: 85.8-100%), with overall PABAK of 1.Recommendations are provided to mitigate the frequency of occurrence of the residual use errors observed. Integration pathways were discussed to identify opportunities and limitations of adopting POCKIT™ Central for screening and diagnostic testing purposes. CONCLUSIONS: Point-of-care PCR testing in care homes can be considered with appropriate preparatory steps and safeguards. Further diagnostic accuracy evaluations and in-service evaluation studies should be conducted, if the test is to be implemented more widely, to build greater certainty on this initial exploratory analysis.

COVID-19-related acute kidney injury; incidence, risk factors and outcomes in a large UK cohort.

BACKGROUND: Acute kidney injury (AKI) is common among patients hospitalised with COVID-19 and associated with worse prognosis. The aim of this study was to investigate the epidemiology, risk factors and outcomes of AKI in patients with COVID-19 in a large UK tertiary centre. METHODS: We analysed data of consecutive adults admitted with a laboratory-confirmed diagnosis of COVID-19 across two sites of a hospital in London, UK, from 1st January to 13th May 2020. RESULTS: Of the 1248 inpatients included, 487 (39%) experienced AKI (51% stage 1, 13% stage 2, and 36% stage 3). The weekly AKI incidence rate gradually increased to peak at week 5 (3.12 cases/100 patient-days), before reducing to its nadir (0.83 cases/100 patient-days) at the end the study period (week 10). Among AKI survivors, 84.0% had recovered renal function to pre-admission levels before discharge and none required on-going renal replacement therapy (RRT). Pre-existing renal impairment [odds ratio (OR) 3.05, 95%CI 2.24-4,18; p <  0.0001], and inpatient diuretic use (OR 1.79, 95%CI 1.27-2.53; p <  0.005) were independently associated with a higher risk for AKI. AKI was a strong predictor of 30-day mortality with an increasing risk across AKI stages [adjusted hazard ratio (HR) 1.59 (95%CI 1.19-2.13) for stage 1; p < 0.005, 2.71(95%CI 1.82-4.05); p < 0.001for stage 2 and 2.99 (95%CI 2.17-4.11); p < 0.001for stage 3]. One third of AKI3 survivors (30.7%), had newly established renal impairment at 3 to 6 months. CONCLUSIONS: This large UK cohort demonstrated a high AKI incidence and was associated with increased mortality even at stage 1. Inpatient diuretic use was linked to a higher AKI risk. One third of survivors with AKI3 exhibited newly established renal impairment already at 3-6 months.

Ion-Channel modulator TH1177 reduces glomerular injury and serum creatinine in chronic mesangial proliferative disease in rats.

BACKGROUND: T-type calcium channels (TTCC) are involved in mesangial cell proliferation. In acute thy-1 nephritis in the rat TTCC inhibition reduces glomerular damage and cell proliferation. This work is extended here by a study of the non-selective TTCC inhibitor TH1177 in a chronic model of proliferative glomerulonephritis (GN) including late treatment starting after the initial inflammation has resolved. The objective was to determine the effects of TH1177 in a model of chronic mesangioproliferative renal disease. METHODS: Chronic GN was induced in WKY rats by unilateral nephrectomy (day - 7) followed by day 0 injection of Ox7 thy-1 mAb. Treatment with TH1177 (10-20 mg/Kg daily IP) was started on day 2 (early treatment) or on day 14 (late treatment) and compared to vehicle-treated controls until sacrifice at day 42. Glomerular disease was assessed with a damage score, fibrosis assay, cellular counts and renal function measured by serum creatinine. RESULTS: Treatment with TH11777 was associated with reduced serum creatinine, less glomerular damage, reduced fibrosis and reduced glomerular cellularity. The results for early and late TH1177 treatments were essentially the same and differed significantly from vehicle. CONCLUSIONS: The ion-channel modulator TH1177 is capable of improving glomerular outcome in chronic rat GN even when treatment starts 14 days after initiation of the disease. These data are discussed in the context of the possible targets of TH1177 including TTCC, TRP family, Stim/Orai group and other cation channels. The work supports the use of genetic models to examine the roles of individual cation channels in progressive glomerulonephritis to further define the targets of TH1177.

Biological variation of measured and estimated glomerular filtration rate in patients with chronic kidney disease.

When assessing changes in glomerular filtration rate (GFR) it is important to differentiate pathological change from intrinsic biological and analytical variation. GFR is measured using complex reference methods (e.g., iohexol clearance). In clinical practice measurement of creatinine and cystatin C are used in the Modification of Diet in Renal Disease [MDRD] or Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI] equations to provide estimated GFR. Here we studied the biological variability of measured and estimated GFR in twenty nephrology outpatients (10 male, 10 female; median age 71, range 50-80 years) with moderate CKD (GFR 30-59 ml/min per 1.73 m2). Patients underwent weekly GFR measurement by iohexol clearance over four consecutive weeks. Simultaneously, GFR was estimated using the MDRD, CKD-EPIcreatinine, CKD-EPIcystatinC and CKD-EPIcreatinine+cystatinC equations. Within-subject biological variation expressed as a percentage [95% confidence interval] for the MDRD (5.0% [4.3-6.1]), CKD-EPIcreatinine (5.3% [4.5-6.4]), CKD-EPIcystatinC (5.3% [4.5-6.5]), and CKD-EPIcreatinine+cystatinC (5.0% [4.3-6.2]) equations were broadly equivalent. The within-subject biological variation for MDRD and CKD- EPIcreatinine+cystatinC estimated GFR were each significantly lower than that of the measured GFR (6.7% [5.6-8.2]). Reference change values, the point at which a true change in a biomarker in an individual can be inferred to have occurred with 95% probability were calculated. By the MDRD equation, positive and negative reference change values were 15.1% and 13.1% respectively. If an individual's baseline MDRD estimated GFR (ml/min per 1.73 m2) was 59, significant increases or decreases would be to values over 68 or under 51 respectively. Within-subject variability of estimated GFR was lower than measured GFR. Reference change values can be used to understand GFR changes in clinical practice. Thus, estimates of GFR are at least as reliable as measured GFR for monitoring patients over time.

Increased prevalence of renal cysts in patients with sickle cell disease.

BACKGROUND: Early detection and interventions have enabled patients with sickle cell disease (SCD) to live well into adulthood. Consequently, the chronicity of SCD allows for the insidious manifestation of multisystem complications, including renal damage. Cystic renal lesions are commonly incidentally discovered on ultrasound and computerised tomography (CT) imaging of the abdomen. Most are benign simple cysts, however, difficulties may be encountered if infection, rupture, haemorrhage or cancerous changes develop. We aimed to determine whether patients with SCD have a higher prevalence of simple renal cysts compared to non-SCD individuals. METHODS: Data for a group of 223 patients with SCD who had undergone an ultrasound and/or CT imaging of the abdomen were extracted for comparison with 180 control patients (haemoglobin genotype unknown), matched for age and ethnicity. Scans were evaluated for 198 SCD patients and 180 controls. RESULTS: Renal cysts were found in 58% of the SCD group and 20% of the controls (OR 5.4 (CI 2.6-11.0), RR 2.8 (CI 1.9-4.2)). Bilateral renal cysts were found in 28% of the SCD participants in comparison with 5% of the control group. In those who had one or more cysts identified, the average number of cysts was 3.76 for the SCD group and 1.94 for the controls. Men with SCD were more likely to develop cysts than women (66% vs 53%), as were men without SCD (22% vs 17%). CONCLUSIONS: Simple renal cysts occur more frequently, are more abundant and develop at a younger age in patients with SCD than ethnically-matched controls. Further study of the mechanism underlying cyst formation may shed light on both sickle cell nephropathy and other cystic renal diseases.

How I treat renal complications in sickle cell disease.

Renal disease is one of the most frequent and severe complications experienced by patients with sickle cell disease; its prevalence is likely to increase as the patient population ages. We recommend regular monitoring for early signs of renal involvement and a low threshold for the use of hydroxyurea as preventative measures for end-stage renal disease. Once renal complications are detected, a careful assessment of the patient is required to rule out other causes of renal disease. Proteinuria and hypertension should be managed aggressively and the patient referred to a specialist nephrology center when progressive decline in renal function is noted. For the few patients who develop advanced chronic kidney disease, timely planning for dialysis and transplantation can significantly improve outcome, and we recommend an exchange blood transfusion policy for all patients on the transplant waiting list and for those with a functioning graft. Alongside the invasive treatment regimes, it is important to remember that renal failure in conjunction with sickle cell disease does carry a significant burden of morbidity and that focusing on symptom control has to be central to good patient care.

The eGFR-C study: accuracy of glomerular filtration rate (GFR) estimation using creatinine and cystatin C and albuminuria for monitoring disease progression in patients with stage 3 chronic kidney disease--prospective longitudinal study in a multiethnic population.

BACKGROUND: Uncertainty exists regarding the optimal method to estimate glomerular filtration rate (GFR) for disease detection and monitoring. Widely used GFR estimates have not been validated in British ethnic minority populations. METHODS/DESIGN: Iohexol measured GFR will be the reference against which each estimating equation will be compared. The estimating equations will be based upon serum creatinine and/or cystatin C. The eGFR-C study has 5 components: 1) A prospective longitudinal cohort study of 1300 adults with stage 3 chronic kidney disease followed for 3 years with reference (measured) GFR and test (estimated GFR [eGFR] and urinary albumin-to-creatinine ratio) measurements at baseline and 3 years. Test measurements will also be undertaken every 6 months. The study population will include a representative sample of South-Asians and African-Caribbeans. People with diabetes and proteinuria (ACR ≥30 mg/mmol) will comprise 20-30% of the study cohort.2) A sub-study of patterns of disease progression of 375 people (125 each of Caucasian, Asian and African-Caribbean origin; in each case containing subjects at high and low risk of renal progression). Additional reference GFR measurements will be undertaken after 1 and 2 years to enable a model of disease progression and error to be built.3) A biological variability study to establish reference change values for reference and test measures.4) A modelling study of the performance of monitoring strategies on detecting progression, utilising estimates of accuracy, patterns of disease progression and estimates of measurement error from studies 1), 2) and 3).5) A comprehensive cost database for each diagnostic approach will be developed to enable cost-effectiveness modelling of the optimal strategy.The performance of the estimating equations will be evaluated by assessing bias, precision and accuracy. Data will be modelled as a linear function of time utilising all available (maximum 7) time points compared with the difference between baseline and final reference values. The percentage of participants demonstrating large error with the respective estimating equations will be compared. Predictive value of GFR estimates and albumin-to-creatinine ratio will be compared amongst subjects that do or do not show progressive kidney function decline. DISCUSSION: The eGFR-C study will provide evidence to inform the optimal GFR estimate to be used in clinical practice. TRIAL REGISTRATION: ISRCTN42955626.

The burden of hyperkalaemia on hospital healthcare resources.

Hyperkalaemia is associated with prolonged hospital admission and worse mortality. Hyperkalaemia may also necessitate clinical consults, therapies for hyperkalaemia and high-dependency bed utilisation. We evaluated the 'hidden' human and organisational resource utilisation for hyperkalaemia in hospitalised patients. This was a single-centre, observational cohort study (Jan 2017-Dec 2020) at a tertiary-care hospital. The CogStack system (data processing and analytics platform) was used to search unstructured and structured data from individual patient records. Association between potassium and death was modelled using cubic spline regression, adjusted for age, sex, and comorbidities. Cox proportional hazards estimated the hazard of death compared with normokalaemia (3.5-5.0 mmol/l). 129,172 patients had potassium measurements in the emergency department. Incidence of hyperkalaemia was 85.7 per 1000. There were 49,011 emergency admissions. Potassium > 6.5 mmol/L had 3.9-fold worse in-hospital mortality than normokalaemia. Chronic kidney disease was present in 21% with potassium 5-5.5 mmol/L and 54% with potassium > 6.5 mmol/L. For diabetes, it was 20% and 32%, respectively. Of those with potassium > 6.5 mmol/L, 29% had nephrology review, and 13% critical care review; in this group 22% transferred to renal wards and 8% to the critical care unit. Dialysis was used in 39% of those with peak potassium > 6.5 mmol/L. Admission hyperkalaemia and hypokalaemia were independently associated with reduced likelihood of hospital discharge. Hyperkalaemia is associated with greater in-hospital mortality and reduced likelihood of hospital discharge. It necessitated significant utilisation of nephrology and critical care consultations and greater likelihood of patient transfer to renal and critical care.