3' Untranslated Region Structural Elements in CYP24A1 Are Associated With Infantile Hypercalcemia Type 1

Loss-of-function mutations in the CYP24A1 protein-coding region causing reduced 25 hydroxyvitamin D (25OHD) and 1,25 dihydroxyvitamin D (1,25(OH)₂ D) catabolism have been observed in some cases of infantile hypercalcemia type 1 (HCINF1), which can manifest as nephrocalcinosis, hypercalcemia and adult-onset hypercalciuria, and renal stone formation. Some cases present with apparent CYP24A1 phenotypes but do not exhibit pathogenic mutations. Here, we assessed the molecular mechanisms driving apparent HCINF1 where there was a lack of CYP24A1 mutation. We obtained blood samples from 47 patients with either a single abnormality of no obvious cause or a combination of hypercalcemia, hypercalciuria, and nephrolithiasis as part of our metabolic and stone clinics. We used liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine serum vitamin D metabolites and direct sequencing to confirm CYP24A1 genotype. Six patients presented with profiles characteristic of altered CYP24A1 function but lacked protein-coding mutations in CYP24A1. Analysis upstream and downstream of the coding sequence showed single nucleotide variants (SNVs) in the CYP24A1 3' untranslated region (UTR). Bioinformatics approaches revealed that these 3' UTR abnormalities did not result in microRNA silencing but altered the CYP24A1 messenger RNA (mRNA) secondary structure, which negatively impacted translation. Our experiments showed that mRNA misfolding driven by these 3' UTR sequence-dependent structural elements was associated with normal 25OHD but abnormal 1,25(OH)₂ D catabolism. Using CRISPR-Cas9 gene editing, we developed an in vitro mutant model for future CYP24A1 studies. Our results form a basis for future studies investigating structure-function relationships and novel CYP24A1 mutations producing a semifunctional protein. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Predicting Strict Trifecta Outcomes after Robot-Assisted Partial Nephrectomy: Comparison of RENAL, PADUA, and C-Index Scores

Nephrometry scores are designed to characterize tumors and stratify the surgical complexity. It remains unclear as to which nephrometry score can accurately predict the surgical outcomes. We aimed to assess the utility of radius, exophytic/endophytic, nearness, anterior/posterior, location (RENAL), preoperative aspects and dimensions used for anatomic classifications (PADUA), and centrality index (C-index) nephrometry scores for predicting the strict Trifecta achievement from a single institution series robotic-assisted partial nephrectomy (RAPN). We retrospectively identified the prospectively maintained robotic surgery database records of 91 patients who underwent RAPN between June 2015 and September 2020 in Antalya Training and Research Hospital. The main outcome of the study was the achievement of strict Trifecta (negative surgical margin, no major urologic complications, warm ischemia time ≤25 min, and ≥85% preservation of estimated glomerular filtration rate). A multivariable analysis was performed to identify the factors of strict Trifecta success. The mean patient age was 55.82 ± 13.37 years with a median clinical tumor size of 3.5 cm (IQR 2.5–4.9). The median RENAL, PADUA, and C-index score were 7(IQR 6–8), 8(IQR 7–10), and 2.01(IQR 1.64–2.72), respectively. A strict Trifecta could be achieved in 54 patients (59.3%). Clinical tumor size (P = 0.011), RENAL risk groups (low:reference; intermediate; P = 0.040; high; P = 0.009), PADUA risk groups (low:reference; intermediate; P = 0.044; high; P = 0.001) and C-index risk groups (low:reference; high; P = 0.015) were the independent predictors of strict Trifecta attainment in the multivariate analysis. None of the nephrometry scores were a superior predictor compared to other nephrometry scores in comparative analysis. RENAL, PADUA, and C-index scores were all independent predictors of a strict Trifecta achievement. Our comprehensive comparison of the three scores identified that none of the nephrometry scores proved to be inferior to others nephrometry scores.

Nephrometry Scores: Can Preoperative Assessment of Sectional Imaging Really Mirror Intraoperative Renal Tumor Anatomy?

INTRODUCTION

To compare RENAL, preoperative aspects and dimensions used for an anatomical (PADUA) classification, and Mayo Adhesive Probability (MAP) scores with the respective intraoperative findings and surgeon's assessment in predicting surgical outcome of patients undergoing partial nephrectomy.

METHODS

Data of 150 eligible patients treated at the University Medical Center Mannheim between 2016 and 2018 were analyzed. Tumors were radiologically and intraoperatively assessed by PADUA, RENAL, and MAP scores and surgeon's assessment. Correlations and regression models were created to predict ischemia time (IT), major complications, and Trifecta (negative surgical margin, IT < 25 min, and absence of major complications).

RESULTS

There were strong correlations between radiological and intraoperative RENAL (r = 0.68; p < 0.001) and PADUA scores (r = 0.72; p < 0.001). Radiological RENAL, PADUA, and MAP scores and surgeon's assessment were independent predictors of Trifecta (OR = 0.71, p = 0.015; OR = 0.77, p = 0.035; OR = 0.65, p = 0.012; OR = 0.40, p = 0.005, respectively). IT showed significant associations with radiological RENAL, PADUA, and surgeon's assessment (OR = 1.41, p = 0.033; OR = 1.34, p = 0.044; OR = 3.04, p = 0.003, respectively). MAP score proved as only independent predictor of major complications (OR = 2.12, p = 0.002).

CONCLUSION

Radiologically and intraoperatively assessed scores correlated well with each other. Intraoperative nephrometry did not outperform radiological scores in predicting outcome confirming the value of the existing systems. MAP score correlates well with surgeon's assessment of perirenal fat and major complications underlining the importance of perirenal fat characteristics.

Simplified PADUA Renal (SPARE) Nephrometry Scoring System: External Validation, Interobserver Variability, and Comparison with RENAL and PADUA in a Single-center Robotic Partial Nephrectomy Series

BACKGROUND

The RENAL (radius [R], exophytic/endophytic [E], nearness to collecting system/sinus [N], anterior/posterior [A], and location relative to polar lines [L]) and the PADUA (preoperative aspects and dimensions used for an anatomical classification) scores help in quantifying tumor complexity. However, nephrometry scoring systems have low interobserver variability. To simplify and improve score reproducibility, a new Simplified PADUA Renal (SPARE) scoring system was introduced.

OBJECTIVE

To externally validate the SPARE nephrometry scoring system and to determine its interobserver variability.

DESIGN, SETTING, AND PARTICIPANTS

A total of 202 patients were included in the analysis. We performed a retrospective analysis of robot-assisted partial nephrectomy (RAPN) cases for a single renal mass performed at a single academic institution during the period 2008-2018. For each renal mass, PADUA, RENAL, and SPARE nephrometry scores were calculated.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Three urology residents (URs), two urology attendings (UAs), two radiology residents (RRs), and one radiology attending (RA) retrospectively reviewed computed tomography scans blinded to clinical outcomes. The accuracy of the SPARE nephrometry score in the prediction of any complication (Clavien grade ≥1) was compared with other scoring systems in a univariable and a multivariate fashion. The area under the curve (AUC) and kappa statistics were used to assess interobserver variability of the SPARE score.

RESULTS AND LIMITATIONS

The SPARE score was not inferior to the PADUA and RENAL scores (AUC 0.61, 0.59, and 0.57, respectively, p = 0.43). Patients with intermediate to high SPARE scores had longer operative time (158 vs 135 min, p = 0.10) and a higher rate of complications (28% vs 14%, p = 0.012). Univariable analysis predicting overall complications showed that RRs performed slightly better than URs and UAs using the SPARE score. Interobserver agreement was 84% between an RA and an RR (kappa 0.42), 85% between an RA and a UA (kappa 0.39), and 85% between an RA and a UR (kappa 0.45).

CONCLUSIONS

These findings confirm that the SPARE nephrometry scoring system is a reproducible and easy tool offering overall fair interobserver agreement regardless of years of training or type of practice, while maintaining the predictive capabilities of more established nephrometry scores.

PATIENT SUMMARY

In this study, a novel and simple classification system was assessed using a sample of cases from our institution to define surgical complexity renal masses detected on radiological imaging. Our findings suggest that this tool can be useful in clinical practice to facilitate the characterization of renal masses and predict the complications of surgical treatment.

Long-term effects of socioeconomic status on the incidence of decreased glomerular filtration rate in a Southeast Asian cohort

BACKGROUND

There is limited information on the role of low socioeconomic status (SES) in the development of new chronic kidney disease (CKD) in the general population, especially from developing countries. This study will test the hypothesis that low SES increases the risk of incidence of decreased glomerular filtration rate (GFR, used as an estimate for CKD) in a Thai worker cohort.

METHOD

In this prospective, longitudinal observational study, we evaluated the association of income and educational attainment on incident decreased GFR (iGFR <60 mL/min/1.73 m²) over a 27-year period in employees of Electricity Generating Authority of Thailand. In 1985, subjects participated in a health survey and were re-examined in 1997, 2002, 2007 and 2012. Education was classified into three categories: low, 0-8th grade; medium, 9-12th grade; and high, >12th grade. Income was categorised as follows: low <10 000 Thai Baht (THB)/month; medium, 10 000-20 000 THB/month; and high, >20 000 THB/month. HRs of iGFR<60 mL/min/1.73 m² were estimated using Cox interval-censored models with high income or education as the reference groups after adjustments for clinical risk factors.

RESULTS

Participants (n=3334) were followed for 23 (15, 27) years. When evaluated separately, both education and income were risk factors for iGFR<60 mL/min/1.73 m² (adjusted HR education: medium-1.26 (95% CI 1.13 to1.42) and low-1.57 (95% CI 1.36 to 1.81) and adjusted HR income: medium-1.21 (95% CI 0.97 to 1.50) and low-1.47 (95% CI 1.18 to 1.82)). When both income and education were included together, low and medium education remained independently associated with iGFR<60 mL/min/1.73 m².

CONCLUSIONS

Low education was independently associated with increased risk of decreased GFR in a Thai worker population. Strategies to identify risk factors among low SES may be useful to prevent early CKD.

The superiority of contact surface area as a predictor of renal cortical volume change after partial nephrectomy compared to RENAL, PADUA and C-index: an approach using computed tomography-based renal volumetry

Objective: To evaluate the renal cortical volume (RCV) change after nephron sparing surgery and the predictive value of the nephrometry score in RCV preservation after partial nephrectomy. Materials and methods: Overall, 162 patients with renal tumors that were treated with open partial nephrectomy were retrospectively analyzed. The contact surface area (CSA), RENAL, PADUA and C-index scores were obtained from a preoperative CT scan. The RCV of the tumor-bearing kidney was measured preoperatively and postoperatively using dedicated software. The correlation between the four nephrometry scores and perioperative parameters were evaluated and the scores were compared in terms of their ability to predict a reduction in the RCV. Results: All scores showed a significant association with reduction in RCV (all p < 0.001), percent reduction in RCV (all p < 0.001) and estimated blood loss (all p < 0.05). Only the CSA and PADUA scores showed a significant association with percent reduction in eGFR (p = 0.038 and p = 0.026, respectively). On multivariate analysis, the CSA, PADUA and C-index scores independently affected the percent reduction in RCV (p = 0.003, p = 0.025 and p = 0.013, respectively). On ROC curve analysis, CSA was a better independent predictor of a greater than 10% and 20% reduction in the RCV (AUC 0.87 and 0.72, respectively). Conclusion: CT-based RCV measurement successfully differentiated the RCV change after partial nephrectomy. Compared to the other three nephrometry scores, CSA was a superior predictor of RCV change in the operated kidney.

Interobserver Agreement of the Estimated Contact Surface Area System for Renal Masses

BACKGROUND

Nephrometry scores have been designed to assist in standardization of renal masses before nephron-sparing surgery. Estimated contact surface area (eCSA) has been recently described. However, its reproducibility between raters has not been rigorously explored. Our aim was to examine the reproducibility of eCSA and Radius, Exophytic, Nearness, Anterior, Line (RENAL) score (RS) nephrometry systems for renal masses by studying the interobserver agreement between 4 raters.

MATERIALS AND METHODS

We reviewed the cross-sectional images (computed tomography, magnetic resonance imaging) of patients who underwent nephron-sparing surgery (open, laparoscopic, and robotic). Four urologists independently scored the renal tumors according to the eCSA and RS systems. Scoring was done separately for each nephrometry system. Interobserver agreement was assessed for total scores and separate components of each system by calculating the intraclass correlation coefficient (ICC).

RESULTS

Ninety patients were scored to achieve power of 83% with α = 0.05. eCSA and RS demonstrated excellent interobserver agreement (ICC = 0.89 for both). The radius component of eCSA and RS had the highest ICC (0.97 and 0.9, respectively) compared with the other components. Location and anterior/posterior components of RS showed poor interobserver correlation (ICC = 0.69 and 0.50, respectively). Maximal difference in RS complexity group assignment was 1 of 43 (47.8%) of cases.

CONCLUSION

eCSA has excellent interobserver agreement, similar to RS. Directly measurable anatomic variables have better interobserver correlation compared with qualitative variables. These results strengthen the applicability of eCSA as a surgical complexity metric for renal surgery.

The role of RENAL, PADUA and C-index scoring systems in predicting the results of partial nephrectomy without ischemia

OBJECTIVE

To evaluate the feasibility and renoprotective effect of off-clamp partial nephrectomy (PN) by renal scoring systems.

METHODS

After approval of the local ethics committee, the radiological and clinical data of patients with renal masses who underwent PN between January 2012 and January 2017 were evaluated in two university hospitals. Total 132 patients who underwent open surgery and off-clamp technique were included. All patients underwent contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) preoperatively. Preoperative demographic data, estimated glomerular filtration rate (e-GFR) and hematocrit changes, operation time, tumor volume and hospitalization time from patients were evaluated separately and statistically for each of the three scoring systems.

RESULTS

Our study consisted of 132 patients with a mean age of 53.9 ± 13.9 with 69 male and 63 female. Statistically significant difference between the risk groups in RENAL and PADUA scoring were found according to tumor T stage and tumor volüme (p <0.005). Statistically significant difference was only found between risk groups of RENAL scoring system in e-GFR reduction (p<0.05). There was no statistically significant difference between the groups in the complications of all three classification systems (p > 0.005).

CONCLUSIONS

In our study, all three scoring sytem successfully predicted the surgical complexity ve surgical outcomes and our results indicate that off-clamp PN has similar success and complications rates when compared to the literature. The off-clamp PN must be kept in mind to maintain postoperative renal functions eligible patients.

Nephrometry Scores: The Effect of Imaging on Routine Read-out and Prediction of Outcome of Nephron-sparing Surgery

BACKGROUND/AIM

This study investigated the impact of available preoperative imaging on the reliability and predictive accuracy of RENAL and PADUA nephrometry-scoring systems for renal tumors.

PATIENTS AND METHODS

Five urologists determined RENAL and PADUA scores using preoperative imaging data (computed tomography and magnetic resonance imaging) of 100 patients admitted for partial nephrectomy with the following combinations: T0: transverse planes without excretory phase (EP), TC0: transverse and coronal planes without EP, TC1: transverse and coronal planes with EP. Reference standard was obtained by a uro-radiologist. Ischemia time was used as surrogate for surgical complexity.

RESULTS

Assignment of EP significantly reduced interobserver-variability among urologists (p<0.0001). Predictive accuracy for surgical complexity or correct assignment to nephrometry risk groups did not depend on image planes or EP.

CONCLUSION

Interobserver variability, but not predictive accuracy of nephrometric systems, is affected by additional usage of EP.

Nickel exposure and prevalent albuminuria and β2-microglobulinuria: evidence from a population-based study

BACKGROUND

High exposure to nickel could induce renal dysfunction in rodents and occupational workers. However, little is known about the effects of non-occupational exposure to nickel on renal health in the general population. We aimed to examine the associations of urinary nickel concentrations with albuminuria and β2-microglobulinuria in Chinese adults.

METHODS

2115 non-institutionalised Chinese men and women aged 55-76 years from Beijing and Shanghai were included. Urinary nickel concentrations were assessed by inductively coupled plasma mass spectroscopy. Plasma uric acid, urea nitrogen, C reactive protein and urinary albumin, β2-microglobulin and creatinine were measured. Albuminuria was defined as urinary albumin ≥30 mg/g creatinine, and β2-microglobulinuria was defined as urinary β2-microglobulin ≥200 µg/g creatinine.

RESULTS

Median concentration of urinary nickel was 3.95 μg/g creatinine (IQR: 2.57-6.71 μg/g creatinine), and prevalence of albuminuria, β2-microglobulinuria and both albuminuria and β2-microglobulinuria was 22.1%, 24.5% and 9.7%, respectively. Comparing the highest with the lowest quartile of urinary nickel, the ORs (95% CIs) were 1.99 (1.46 to 2.78) for albuminuria, 1.44 (1.07 to 1.95) for β2-microglobulinuria, and 2.95 (1.74 to 4.97) for both albuminuria and β2-microglobulinuria, after adjustment for demographic characteristics, lifestyle behaviours, body mass index, hypertension and diabetes. The association remained significant when further controlling for inflammatory markers or other heavy metals (all p trend <0.05).

CONCLUSIONS

This study suggested that urinary nickel levels were positively associated with albuminuria and β2-microglobulinuria in Chinese men and women, who had relatively low background nickel exposure. More prospective studies are needed to confirm our findings.

Chronic kidney disease among adult participants of the ELSA-Brasil cohort: association with race and socioeconomic position

BACKGROUND

There is increased interest in understanding why chronic kidney disease (CKD) rates vary across races and socioeconomic groups. We investigated the distribution of estimated glomerular filtration rate (eGFR), urinary albumin-creatinine ratio (ACR) and CKD according to these factors in Brazilian adults.

METHODS

Using baseline data (2008-2010) of 14,636 public sector employees (35-74 years) enrolled in the Brazilian Longitudinal Study of Adult Health (ELSA)-Brasil multicentre cohort, we estimated the prevalence of CKD by sex, age, race and socioeconomic factors. CKD was defined as ACR ≥ 30 mg/g and/or eGFR < 60 mL/min/1.73 m(2). GFR was estimated by CKD epidemiology collaboration without correction for race. We used logistic regression to estimate the association of race and socioeconomic position (education, income, social class and occupational nature) with CKD after adjusting for sex, age and several health-related factors.

RESULTS

The prevalence of high ACR or low eGFR, in isolation and combined, increased with age, and was higher in individuals with lower socioeconomic position and among black individuals and indigenous individuals. The overall prevalence of CKD was 8.9%. After full adjustments, it was similar in men and women (OR=0.90; 95% CI 0.79 to 1.02) and increased with age (OR=1.07; 95% CI 1.06 to 1.08). Compared to white individuals, black individuals (OR=1.23; 95% CI 1.03 to 1.47), 'pardos' (OR=1.16; 95% CI 1.00 to 1.35) and Indigenous (OR=1.72; 95% CI 1.07 to 2.76) people had higher odds for CKD. Having high school (OR=1.15; 95% CI 1.00 to 1.34) or elementary education (OR=1.23; 95% CI 1.03 to 1.47) increased the odds for CKD compared to those having a university degree.

CONCLUSIONS

There were marked discrepancies in the increases in reduced eGFR and high ACR with age and race. The higher prevalences of CKD in individuals with lower educational status and in non-whites were not explained by differences in health-related factors.

Evaluation of promoter hypomethylation and expression of p73 as a diagnostic and prognostic biomarker in Wilms' tumour

AIMS

A member of the p53 family, the p73 gene is essential for the maintenance of genomic stability, DNA repair and apoptosis regulation. This study was designed to evaluate the utility of expression and DNA methylation patterns of the p73 gene in the early diagnosis and prognosis of Wilms' tumour (WT).

METHODS

Methylation-specific PCR, semi-quantitative (sq-PCR), real-time quantitative PCR (qRT-PCR), receiver operating characteristic (ROC), and survival and hazard function curve analyses were utilised to measure the expression and DNA methylation patterns of p73 in WT tissue samples with a view to assessing diagnostic and prognostic value.

RESULTS

The relative expression of p73 mRNA was higher, while the promoter methylation level was lower in the WT than the control group (p<0.05) and closely associated with poor survival prognosis in children with WT (p<0.05). Increased expression and decreased methylation of p73 were correlated with increasing tumour size, clinical stage and unfavourable histological differentiation (p<0.05). ROC curve analysis showed areas under the curve of 0.544 for methylation and 0.939 for expression in WT venous blood, indicating the higher diagnostic yield of preoperative p73 expression.

CONCLUSIONS

Preoperative venous blood p73 level serves as an underlying biomarker for the early diagnosis of WT. p73 overexpression and concomitantly decreased promoter methylation are significantly associated with poor survival in children with WT.

Comparison of robot-assisted and laparoscopic partial nephrectomy for complex renal tumours with a RENAL nephrometry score ≥7: peri-operative and oncological outcomes

OBJECTIVE

To evaluate the peri-operative, functional and oncological outcomes of robot-assisted partial nephrectomy (RAPN) and laparoscopic partial nephrectomy (LPN) for moderately or highly complex tumours (defined as RENAL nephrometry score ≥7).

PATIENTS AND METHODS

We retrospectively analysed the medical charts of 216 patients with complex tumours who underwent LPN (n = 135) or RAPN (n = 81) between 2008 and 2014. Peri-operative data, pathological variables, complications, functional and oncological outcomes were reviewed.

RESULTS

Demographic characteristics were similar in the two groups. LPN was associated with a longer operating time (149.6 vs 135.6 min; P = 0.017) and greater estimated blood loss (220.8 vs 196.5 mL; P = 0.013). RAPN was associated with a higher direct cost. There were no differences in warm ischaemia time, transfusion rate, conversion rate, hospital stay, operative complications and estimated glomerular filtration rate change at 6 months after surgery. The mean follow-ups for LPN and RAPN were 31.4 and 16.5 months, respectively. The 3-year recurrence-free survival rate was 95.2% for LPN and 97.1% for RAPN (P = 0.71).

CONCLUSION

In patients with complex tumours, RAPN and LPN provided acceptable and similar results in terms of peri-operative, functional and oncological outcomes. RAPN was superior to LPN in terms of estimated blood loss and operating time, and LPN was the more cost-effective approach. Both surgery techniques remain viable options in the management of complex tumours with RENAL scores ≥7.

Endotoxin detection in end-stage kidney disease

AIMS

Endotoxin detection assays are not validated for use in end-stage kidney disease (ESKD). We investigated the accuracy and precision of the kinetic turbidimetric Limulus amoebocyte lysate (LAL) assay to detect endotoxin in plasma from patients with ESKD. Optimisation of endotoxin recovery from plasma using the detergent Tween 80 was also explored.

METHODS

Plasma samples from 7 patients with ESKD and 7 healthy subjects were spiked with different concentrations of endotoxin. Repeated measurements for endotoxin at each level of spike were performed to assess the accuracy and precision of spike recovery. Endotoxin recovery in plasma samples diluted in Tween 80 and water was compared.

RESULTS

Mean endotoxin spike recovery was 111.6% and 125.2% in ESKD and healthy subjects, respectively. There was no statistical difference in spike recovery between ESKD and healthy plasma. Precision of the LAL assay in plasma spiked with low (0.05 EU/mL) and high (0.5 EU/mL) concentration of endotoxin spikes was 24.1% and 8.9%, respectively. The use of Tween 80 as a diluent for plasma significantly improved spike recovery in ESKD plasma (100.1% vs 70.4%, p<0.001).

CONCLUSIONS

The kinetic LAL turbidimetric assay is a valid tool for the detection of blood endotoxin in patients with ESKD, although in blood specimens with low-level endotoxemia (≤0.05 EU/mL) the assay may be less accurate and precise. Tween 80 can be used as a diluent to optimise recovery of endotoxin in ESKD plasma.