Quantitative assessment of glomerular basement membrane collagen IV α chains in paraffin sections from patients with focal segmental glomerulosclerosis and Alport gene variants.

Focal segmental glomerulosclerosis (FSGS) lesions have been linked to variants in COL4A3/A4/A5 genes, which are also mutated in Alport syndrome. Although it could be useful for diagnosis, quantitative evaluation of glomerular basement membrane (GBM) type IV collagen (colIV) networks is not widely used to assess these patients. To do so, we developed immunofluorescence imaging for collagen α5(IV) and α1/2(IV) on kidney paraffin sections with Airyscan confocal microscopy that clearly distinguishes GBM collagen α3α4α5(IV) and α1α1α2(IV) as two distinct layers, allowing quantitative assessment of both colIV networks. The ratios of collagen α5(IV):α1/2(IV) mean fluorescence intensities (α5:α1/2 intensity ratios) and thicknesses (α5:α1/2 thickness ratios) were calculated to represent the levels of collagen α3α4α5(IV) relative to α1α1α2(IV). The α5:α1/2 intensity and thickness ratios were comparable across all 11 control samples, while both ratios were significantly and markedly decreased in all patients with pathogenic or likely pathogenic Alport COL4A variants, supporting validity of this approach. Thus, with further validation of this technique, quantitative measurement of GBM colIV subtype abundance by immunofluorescence, may potentially serve to identify the subgroup of patients with FSGS lesions likely to harbor pathogenic COL4A variants who could benefit from genetic testing.

Alport syndrome and Alport kidney diseases - elucidating the disease spectrum.

PURPOSE OF REVIEW: With the latest classification, variants in three collagen IV genes, COL4A3 , COL4A4 , and COL4A5 , represent the most prevalent genetic kidney disease in humans, exhibiting diverse, complex, and inconsistent clinical manifestations. This review breaks down the disease spectrum and genotype-phenotype correlations of kidney diseases linked to genetic variants in these genes and distinguishes "classic" Alport syndrome (AS) from the less severe nonsyndromic genetically related nephropathies that we suggest be called "Alport kidney diseases". RECENT FINDINGS: Several research studies have focused on the genotype-phenotype correlation under the latest classification scheme of AS. The historic diagnoses of "benign familial hematuria" and "thin basement membrane nephropathy" linked to heterozygous variants in COL4A3 or COL4A4 are suggested to be obsolete, but instead classified as autosomal AS by recent expert consensus due to a significant risk of disease progression. SUMMARY: The concept of Alport kidney disease extends beyond classic AS. Patients carrying pathogenic variants in any one of the COL4A3/A4/A5 genes can have variable phenotypes ranging from completely normal/clinically unrecognizable, hematuria without or with proteinuria, or progression to chronic kidney disease and kidney failure, depending on sex, genotype, and interplays of other genetic as well as environmental factors.

Clinicopathological Characteristics and Impacts on Clinical Outcomes of Thrombotic Microangiopathy Lesions in Patients with Immunoglobulin A Nephropathy in Thailand.

INTRODUCTION: More reports of thrombotic microangiopathy (TMA) in immunoglobulin A (IgA) nephropathy suggest its association with poor clinical outcomes. However, the prevalence and clinical significance of TMA in IgA nephropathy have not been widely studied in different populations. METHODS: Kidney biopsies of all patients with primary IgA nephropathy from 1995 to 2015 at the King Chulalongkorn Memorial Hospital, Thailand, were retrospectively reviewed and reclassified by two pathologists following the Oxford MEST-C classification. TMA lesions were detected based solely on light microscopic findings. Associations between the presence of TMA and clinical data, other pathologic findings, and clinical outcomes were studied. RESULTS: Among 267 patients with primary IgA nephropathy, 166 had adequate clinical data and kidney tissues for the analysis. TMA was observed in 21 patients (13%) and was associated with higher mean arterial pressure (MAP), history of malignant hypertension, higher proteinuria, and lower estimated glomerular filtration rate (eGFR) at diagnosis compared to those without TMA. According to the Oxford MEST-C classification, TMA showed a significant association with severe tubular atrophy/interstitial fibrosis (T2) but not with mesangial hypercellularity (M1), endocapillary hypercellularity (E1), segmental glomerulosclerosis (S1), or crescents (C1-2). After a median follow-up of 50 months, patients with TMA had a significantly higher risk of progression to end-stage kidney disease (ESKD) (hazard ratio [HR] 5.8, 95% confidence interval [CI]: 3.1-10.9) and all-cause mortality (HR 3.4, 95% CI: 1.3-8.8). After adjusting for baseline eGFR, MAP, proteinuria, and other pathological lesions, TMA remained an independent predictor of ESKD (adjusted HR 2.4, 95% CI: 1.1-5.4). CONCLUSIONS: Kidney TMA in IgA nephropathy is associated with advanced disease stages, carries a poor prognosis, and thus should be considered in the pathological classification of IgA nephropathy.

Effect of canagliflozin in non-diabetic obese patients with albuminuria: A randomized, double-blind, placebo-controlled trial.

BACKGROUND: Sodium-glucose co-transporter 2 inhibitor (SGLT2i) has been shown to improve renal outcomes in both diabetic and non-diabetic kidney disease. However, the effect of SGLT2i on renal outcomes in patients with non-diabetic obesity is still not established. MATERIALS AND METHODS: In this double-blind, randomized controlled trial, we assigned non-diabetic patients with body mass index (BMI) ≥ 25 kg/m2, persistent 24-hour urine albumin-creatinine ratio (UACR) ≥ 10 mg/gCr, and estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73m2, who had been treated with renin-angiotensin system blockade, to canagliflozin 100 mg daily or placebo for 24 weeks. The reduction in UACR and eGFR at 12 and 24 weeks were explored. (Thai Clinical Trials Registry 20190203003). RESULTS: Of 247 non-diabetic obese patients screened, 32 patients met inclusion criteria and underwent randomization. The median baseline of UACR was 69.1 mg/gCr. There were no statistically significant differences in albuminuria reduction between the groups at 12 weeks and 24 weeks. The estimated GFR in the canagliflozin group decreased significantly from baseline at 12 weeks (-5.39 mL/min/1.73m2; 95% CI -9.81 to -0.97; p = 0.017) but not at 24 weeks (-1.16 mL/min/1.73m2; 95% CI -5.58 to 3.26; p = 0.66), and there was no significant change from baseline in the placebo group at both 12 and 24 weeks. CONCLUSION: Canagliflozin 100 mg daily was well tolerated but did not significantly reduce UACR in non-diabetic obese patients with microalbuminuria. However, a significant temporary decline in eGFR might reflect a subtle reduction in glomerular hyperfiltration.

Exploring hospital practice types and their impact on glomerular pathologic patterns: Insights from the largest kidney biopsy cohort in Thailand.

BACKGROUND: This study aims to investigate the influence of different kidney biopsy practices on the prevalence of glomerular pathologic patterns in the largest kidney biopsy registry in Thailand. METHODS: We conducted a retrospective review of kidney biopsy records from the period between 2000 and 2014. The records were obtained from 2 major institutions: King Chulalongkorn Memorial Hospital, a large university-based hospital, and the Kidney Center Bangkok Hospital, which provides pathology services to hospitals throughout Thailand. The study included native kidney biopsies from all provinces in Thailand, excluding paediatric patients, kidney transplant recipients, and cases of inadequate and repeated biopsies. Patient demographics, indications for biopsy, and final glomerular diagnoses were compared across different hospital practice settings: university (UVH), private (PVH) and public (PBH). RESULTS: A total of 5893 eligible native kidney biopsies were identified from a pool of 7005 biopsies conducted over a 15-year period in 25 provinces throughout Thailand. The 3 most common indications for biopsy were suspected kidney involvement in systemic lupus erythematosus (SLE) (29%), nephrotic syndrome (NS) (29%), and acute glomerulonephritis (AGN)/rapidly progressive glomerulonephritis (RPGN) (13%). The leading indication for biopsy differed across practice types, with suspected kidney involvement in SLE being the primary indication in UVH, while NS took precedence in both PBH and PVH practices. Notably, UVH performed fewer kidney biopsies for asymptomatic urinary abnormalities and diabetes-related indications compared with PVH and PBH. The leading glomerular diagnoses correlated with the biopsy indications, with lupus nephritis (LN) being the most common diagnosis in UVH and PBH practices, whiles immunoglobulin A nephropathy was the predominant diagnosis in PVH practice. CONCLUSION: Hospital practice types significantly impact the prevalence of glomerular pathologic diagnosis patterns in kidney biopsy data, highlighting the importance of considering this influence in epidemiological comparisons.

Constipation and clinical outcomes in peritoneal dialysis: Results from Thailand PDOPPS.

BACKGROUND: Patient-reported outcome measures (PROMs) are widely recognized as valuable predictors of clinical outcomes in peritoneal dialysis (PD). Our study aimed to explore the connections between patient-reported constipation and clinical outcomes. METHODS: We assessed constipation in patients across 22 facilities participating in the Thailand Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) from 2014 to 2017. Constipation diagnosis utilized objective assessment tools such as the Bristol stool form scale (BSFS) and a self-reported questionnaire known as the constipation severity score (CSS). The BSFS is a 7-level scale that visually inspects feces based on texture and morphology, while the CSS measures constipation duration and severity using a 5-point Likert scale for various factors. We employed Cox proportional hazards model regression to determine the associations between constipation and clinical outcomes, including mortality, hemodialysis (HD) transfer and peritonitis. RESULTS: Among 975 randomly selected PD patients from 22 facilities, 845 provided written informed consent, and 729 completed CSS questionnaire. Constipation was prevalent in the PD population (13%), particularly among older patients, those who were caregiver dependent, had diabetes and poorer nutritional status (indicated by lower time-averaged serum albumin, potassium, creatinine and phosphate concentrations). Twenty-seven percent of which experiencing symptoms of constipation for over a year. Notably, self-reported constipation at baseline was significantly associated with a shorter time to first peritonitis and higher rates of peritonitis and death. However, no significant association was found between constipation and HD transfer after adjusting for various factors, including age, gender, PD vintage, comorbidities, shared frailty by study sites and serum albumin. CONCLUSION: Patient-reported constipation independently correlated with increased risks of peritonitis and all-cause mortality, though no such correlation was observed with HD transfer. These findings underscore the need for further investigation to identify effective interventions for constipation in PD patients.

Three-Dimensional Visualization of the Podocyte Actin Network Using Integrated Membrane Extraction, Electron Microscopy, and Machine Learning.

BACKGROUND: Actin stress fibers are abundant in cultured cells, but little is known about them in vivo. In podocytes, much evidence suggests that mechanobiologic mechanisms underlie podocyte shape and adhesion in health and in injury, with structural changes to actin stress fibers potentially responsible for pathologic changes to cell morphology. However, this hypothesis is difficult to rigorously test in vivo due to challenges with visualization. A technology to image the actin cytoskeleton at high resolution is needed to better understand the role of structures such as actin stress fibers in podocytes. METHODS: We developed the first visualization technique capable of resolving the three-dimensional cytoskeletal network in mouse podocytes in detail, while definitively identifying the proteins that comprise this network. This technique integrates membrane extraction, focused ion-beam scanning electron microscopy, and machine learning image segmentation. RESULTS: Using isolated mouse glomeruli from healthy animals, we observed actin cables and intermediate filaments linking the interdigitated podocyte foot processes to newly described contractile actin structures, located at the periphery of the podocyte cell body. Actin cables within foot processes formed a continuous, mesh-like, electron-dense sheet that incorporated the slit diaphragms. CONCLUSIONS: Our new technique revealed, for the first time, the detailed three-dimensional organization of actin networks in healthy podocytes. In addition to being consistent with the gel compression hypothesis, which posits that foot processes connected by slit diaphragms act together to counterbalance the hydrodynamic forces across the glomerular filtration barrier, our data provide insight into how podocytes respond to mechanical cues from their surrounding environment.

Efficacy of Potassium Supplementation in Hypokalemic Patients Receiving Peritoneal Dialysis: A Randomized Controlled Trial.

RATIONALE & OBJECTIVE: Hypokalemia is a common electrolyte abnormality in patients on peritoneal dialysis (PD) and has been associated with increased risks of peritonitis and death. Whether correction of hypokalemia improves these outcomes is unknown. STUDY DESIGN: Multicenter, open-label, prospective, randomized controlled trial. SETTING & PARTICIPANTS: Adult (aged ≥18 years) PD patients with hypokalemia (defined as at least 3 values or an average value <3.5 mEq/L in the past 6 months). Randomization was stratified according to center and residual urine output (≤100 or >100 mL/day). INTERVENTIONS: Random assignment to either protocol-based potassium supplementation (titratable dose of oral potassium chloride to maintain serum potassium of 4-5 mEq/L) or conventional potassium supplementation (reactive supplementation when serum potassium is <3.5 mEq/L) over 52 weeks. Treatment groups were compared using intention-to-treat analyses implemented using Cox proportional hazards regression. OUTCOME: The primary outcome was time from randomization to first peritonitis episode (any organism). Secondary outcomes were all-cause mortality, cardiovascular mortality, hospitalization, and conversion to hemodialysis. RESULTS: A total of 167 patients with time-averaged serum potassium concentrations of 3.33 ± 0.28 mEq/L were enrolled from 6 PD centers: 85 were assigned to receive protocol-based treatment, and 82 were assigned to conventional treatment. The median follow-up time was 401 (IQR, 315-417) days. During the study period, serum potassium levels in the protocol-based treatment group increased to 4.36 ± 0.70 mEq/L compared with 3.57 ± 0.65 mEq/L in the group treated conventionally (mean difference, 0.66 [95% CI, 0.53-0.79] mEq/L; P < 0.001). The median time to first peritonitis episode was significantly longer in the protocol-based group (223 [IQR, 147-247] vs 133 [IQR, 41-197] days, P = 0.03). Compared with conventional treatment, the protocol-based group had a significantly lower hazard of peritonitis (HR, 0.47 [95% CI, 0.24-0.93]) but did not differ significantly with respect to any of the secondary outcomes. Asymptomatic hyperkalemia (>6 mEq/L) without characteristic electrocardiographic changes occurred in 3 patients (4%) in the protocol-based treatment group. LIMITATIONS: Not double-masked. CONCLUSIONS: Compared with reactive potassium supplementation when the serum potassium level falls below 3.5 mEq/L, protocol-based oral potassium treatment to maintain a serum potassium concentration in the range of 4-5 mEq/L may reduce the risk of peritonitis in patients receiving PD who have hypokalemia. TRIAL REGISTRATION: Registered at the Thai Clinical Trials Registry with study number TCTR20190725004.

Spiritual well-being and its relationship with patient characteristics and other patient-reported outcomes in peritoneal dialysis patients: Findings from the PDOPPS.

BACKGROUND: Spiritual well-being (SWB), an individual's understanding of the meaning and purpose of life, may help patients with chronic or terminal illnesses cope with their diseases. This study aimed to assess SWB in patients on peritoneal dialysis (PD), as well as its relationship with patient characteristics and patient-reported outcomes (PRO). METHODS: The data were obtained from questionnaires that formed part of the PD Outcomes and Practice Patterns Study (PDOPPS). Measures used in this study were SWB scores derived from the WHO quality of life, spirituality, religiousness and personal beliefs (WHOQOL-SRPB) tool including 32 items from eight facets; physical (PCS) and mental component summary (MCS) scores of the 12-Item Short-Form Health Survey (SF-12), Center of Epidemiologic Studies Depression Scale-10 (CES-D-10) scores, burden of kidney disease scores and functional status scores. RESULTS: Overall, 529 out of 848 participants (62%) completely responded to the questionnaires and were included in the analysis. Over two-thirds of PD patients (70%) had moderate or higher SWB scores. The SWB scores were significantly lower in patients with age >65 years and unemployed status. SWB scores positively correlated with higher PCS, MCS, burden of kidney disease scores and functional status scores, while negatively correlated with depression scores by CES-D-10 scale. Patients who reported significant depressive symptoms (CES-D-10 score ≥ 10) had significantly lower SWB scores. CONCLUSION: Better SWB was significantly associated with better health-related QOL (HRQOL) and the absence of depressive symptoms. SWB may be an essential consideration in the delivery of high-quality PD.

Association between self-reported appetite and clinical outcomes of peritoneal dialysis patients: Findings from a low middle-income country.

AIM: Patient-reported outcome measures (PROM) has gained international recognition as important predictors of clinical outcomes in peritoneal dialysis (PD). We sought to understand the associations between patient-reported appetite and clinical outcomes. METHODS: In the Thailand Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS), 690 of 848 randomly selected PD patients from 22 facilities reported their appetite by using the short form (three items) of the Appetite and Diet Assessment Tool (ADAT), between 2016 and 2018. In this questionnaire, the patients rated their appetite as well as a change in appetite over time. Cox proportional hazards model regression was used to estimating associations between self-reported appetite and clinical outcomes, including mortality, haemodialysis (HD) transfer and peritonitis. RESULTS: Half of the PD patients reported a good appetite, whereas 34% and 16% reported fair and poor appetites, respectively. Poor appetite was more prevalent among female, diabetic, congestive heart failure, older age and patients who had worse nutritional indicators, including lower time-averaged serum albumin and serum creatinine concentrations, as well as a higher proportions of hypokalaemia and severe hypoalbuminemia (serum albumin <3 g/dl). After adjusting for age, sex, comorbidities, and PD vintage, poor appetite was associated with increased risks of peritonitis (adjusted hazard ratio [HR] 1.73, 95% confidence interval [CI] 1.14-2.62), HD transfer (adjusted HR 2.25, 95% CI 1.24-4.10) and all-cause mortality (adjusted HR 1.60, 95% CI 1.08-2.39) compared to patients with good appetite. CONCLUSION: Patient-reported poor appetite was independently associated with higher risks of peritonitis, HD transfer and all-cause mortality. This warrants further investigation to identify effective interventions.

National feasibility survey of peritoneal dialysis key performance indicators in Thailand from provider perspective.

BACKGROUND: Peritoneal dialysis (PD) has been the main method of renal replacement therapy under the "PD First" policy in Thailand since 2008. Initially, the proposed 13 key performance indicators (KPIs) raised feasibility concerns because of inequitable distribution of resources such as laboratory facilities and/or specialized health-care staff for PD care throughout the country. METHODS: Data availability and goals from the health-care providers' perspective were explored using an online questionnaire survey for all PD centers registered with the Nephrology Society of Thailand from May to June 2016. The availability of essential data required for each KPI indicator to achieve the desired target was assessed using a 5-point Likert scale. RESULTS: Of the 197 centers, 119 responded to the survey (response rate of 60.41%). PD indicators with a high percentage of strongly disagree or disagree were "PD adequacy measured in the last 12 months" (26.83%), "Total weekly Kt/V ≥ 1.7" (24.59%), "3-year PD technique survival" (21.31%), "Serum parathyroid levels within 150 to 500 pg/mL" (16.94%), and a "3-year PD patient survival" (19.01%). As many as 34.17%, 39.19%, 27.27%, 28.93%, and 22.00%, respectively, did not anticipate that the targets could be achieved. Based on the findings from this survey, the national committee concluded that these indicators be removed, and only eight PD indicators were launched. CONCLUSION: Given the importance of KPIs for quality assurance and financial reimbursement, inputs from health-care providers especially data availability and achievement of targets should be considered to ensure feasibility before the final list of indicators are launched.

Intraperitoneal Cefepime Monotherapy Versus Combination Therapy of Cefazolin Plus Ceftazidime for Empirical Treatment of CAPD-Associated Peritonitis: A Multicenter, Open-Label, Noninferiority, Randomized, Controlled Trial.

RATIONALE & OBJECTIVE: Compared to combination therapy, intraperitoneal (IP) cefepime monotherapy for continuous ambulatory peritoneal dialysis (CAPD)-associated peritonitis may provide potential benefits in lowering staff burden, shortening time-consuming antibiotic preparation, and reducing bag contamination risk. This study sought to evaluate whether cefepime monotherapy is noninferior to combination regimens. STUDY DESIGN: Multicenter, open-label, noninferiority, randomized, controlled trial. SETTING & PARTICIPANTS: Adult incident peritoneal dialysis (PD) patients with CAPD-associated peritonitis in 8 PD centers in Thailand. INTERVENTIONS: Random assignment to either IP monotherapy of cefepime, 1g/d, or IP combination of cefazolin and ceftazidime, 1g/d, both given as continuous dosing. OUTCOMES: Primary end point: resolution of peritonitis at day 10 (primary treatment response). SECONDARY OUTCOMES: initial response (day 5), complete cure (relapse/recurrence-free response 28 days after treatment completion), relapsing/recurrent peritonitis, and death from any cause. Noninferiority would be confirmed for the primary outcome if the lower margin of the 1-sided 95% CI was not less than-10% for difference in the primary response rate. A 2-sided 90% CI was used to demonstrate the upper or lower border of the 1-sided 95% CI. RESULTS: There were 144 eligible patients with CAPD-associated peritonitis, of whom 70 and 74 patients were in the monotherapy and combination-therapy groups, respectively. Baseline demographic and clinical characteristics were not different between the groups. The primary response was 82.6% in the monotherapy group and 81.1% in the combination-therapy group (treatment difference, 1.5%; 90% CI, -9.1% to 12.1%; P=0.04). There was no significant difference in the monotherapy group compared with the combination-therapy group in terms of initial response rate (65.7% vs 60.8%; treatment difference, 4.9%; 95% CI, -10.8% to 20.6%; P=0.5) and complete cure rate (80.0% vs 80.6%; treatment difference, -0.6%; 95% CI, -13.9% to 12.8%; P=0.7). Relapsing and recurrent peritonitis occurred in 4.6% and 4.6% of the monotherapy group and 4.2% and 5.6% of the combination-therapy group (P=0.9and P=0.8, respectively). There was nominally higher all-cause mortality in the monotherapy group (7.1% vs 2.7%; treatment difference, 4.4%; 95% CI, -2.6% to 11.5%), but this difference was not statistically significant (P = 0.2). LIMITATION: Not double blind. CONCLUSIONS: IP cefepime monotherapy was noninferior to conventional combination therapy for resolution of CAPD-associated peritonitis at day 10 and may be a reasonable alternative first-line treatment. FUNDING: This study is supported by The Kidney Foundation of Thailand (R5879), Thailand; Rachadaphiseksompotch Fund (RA56/006) and Rachadaphicseksompotch Endorsement Fund (CU-GRS_61_06_30_01), Chulalongkorn University, Thailand; National Research Council of Thailand (156/2560), Thailand; and Thailand Research Foundation (IRG5780017), Thailand. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT02872038.

Interferon-Inducible Protein 10 and Disease Activity in Systemic Lupus Erythematosus and Lupus Nephritis: A Systematic Review and Meta-Analysis.

There is increasing evidence of a correlation between interferon-inducible protein 10 (IP-10) and disease activity of systemic lupus erythematosus (SLE) and lupus nephritis (LN). We conducted a comprehensive search on IP-10 using MEDLINE, Scopus, and Cochrane electronic databases from the beginning to the end of December 2017. All studies that compared serum and/or urine IP-10 between active SLE/LN patients and any control groups were identified and included in this systematic review and meta-analysis. The mean difference (MD) of IP-10 level among active SLE and LN patients, as well as the correlation of IP-10 with disease activity, were meta-analyzed using a random-effects model. From 23 eligible studies, 15 provided adequate data for meta-analysis. Serum IP-10 was significantly elevated in patients with active SLE compared to non-active SLE patients (MD 356.5 pg/mL, 95% CI 59.6 to 653.4, p = 0.019). On the other hand, the levels of serum IP-10 was not different between active LN and non-active LN. However, serum IP-10 was positively correlated with disease activity like SLE disease activity index (SLEDAI) (pooled r = 0.29, 95% CI 0.22 to 0.35, p < 0.001). Furthermore, urine IP-10 tended to be higher in patients with active LN compared to non-active LN patients but this did not reach statistical significance (MD 3.47 pg/mgCr × 100, 95% CI -0.18 to 7.12, p = 0.06). Nevertheless, urine IP-10 was positively correlated with renal SLEDAI (pooled r = 0.29, 95% CI 0.05 to 0.50, p = 0.019). In conclusion, serum and urine IP-10 levels may be useful in monitoring the disease activity of SLE and LN. Serum IP-10 was correlated with systemic disease whereas urine IP-10 was a useful biomarker for detecting active LN.

A Case of Congenital Nephrotic Syndrome with Crescents Caused by a Novel Compound Heterozygous Pairing of NPHS1 Genetic Variants.

Congenital nephrotic syndrome is an autosomal recessive inherited disorder that manifests as steroid-resistant massive proteinuria in the first three months of life. Defects in the glomerular filtration mechanism are the primary etiology. We present a child who developed severe nephrotic syndrome at two weeks of age and eventually required a bilateral nephrectomy. Genetic testing revealed compound heterozygous variants in NPHS1 including a known pathogenic variant and a missense variant of uncertain significance. Light microscopy revealed crescent formation-an atypical finding in congenital nephrotic syndrome caused by nephrin variants-in addition to focal segmental and global glomerulosclerosis. Electron microscopy showed diffuse podocyte foot process effacement. Confocal and Airyscan immunofluorescence microcopy showed aggregation of nephrin in the podocyte cell body that is not a result of diffuse podocyte foot process effacement as seen in minimal change disease. These findings confirm the novel variant as pathogenic.

Ultrastructure expansion microscopy (U-ExM) of mouse and human kidneys for analysis of subcellular structures.

Ultrastructure expansion microscopy (U-ExM) involves the physical magnification of specimens embedded in hydrogels, which allows for super-resolution imaging of subcellular structures using a conventional diffraction-limited microscope. Methods for expansion microscopy exist for several organisms, organs, and cell types, and used to analyze cellular organelles and substructures in nanoscale resolution. Here, we describe a simple step-by-step U-ExM protocol for the expansion, immunostaining, imaging, and analysis of cytoskeletal and organellar structures in kidney tissue. We detail the critical modified steps to optimize isotropic kidney tissue expansion, and preservation of the renal cell structures of interest. We demonstrate the utility of the approach using several markers of renal cell types, centrioles, cilia, the extracellular matrix, and other cytoskeletal elements. Finally, we show that the approach works well on mouse and human kidney samples that were preserved using different fixation and embedding conditions. Overall, this protocol provides a simple and cost-effective approach to analyze both preclinical and clinical renal samples in high detail, using conventional lab supplies and standard widefield or confocal microscopy.

Ultrastructure expansion microscopy (U-ExM) of mouse and human kidneys for analysis of subcellular structures.

Ultrastructure expansion microscopy (U-ExM) involves the physical magnification of specimens embedded in hydrogels, which allows for super-resolution imaging of subcellular structures using a conventional diffraction-limited microscope. Methods for expansion microscopy exist for several organisms, organs, and cell types, and used to analyze cellular organelles and substructures in nanoscale resolution. Here, we describe a simple step-by-step U-ExM protocol for the expansion, immunostaining, imaging, and analysis of cytoskeletal and organellar structures in kidney tissue. We detail the critical modified steps to optimize isotropic kidney tissue expansion, and preservation of the renal cell structures of interest. We demonstrate the utility of the approach using several markers of renal cell types, centrioles, cilia, the extracellular matrix, and other cytoskeletal elements. Finally, we show that the approach works well on mouse and human kidney samples that were preserved using different fixation and storage conditions. Overall, this protocol provides a simple and cost-effective approach to analyze both pre-clinical and clinical renal samples in high detail, using conventional lab supplies and standard widefield or confocal microscopy.

Serum Galactomannan: A Predictor of Poor Outcomes in Peritoneal Dialysis Patients With Fungal Peritonitis.

Introduction: The potential value of serum galactomannan index (GMI) in monitoring treatment response in patients with fungal peritonitis who are receiving peritoneal dialysis (PD) was assessed in the present study. Methods: The study included all Thailand fungal PD-related infectious complications surveillance (MycoPDICS) DATA study participants who had timely PD catheter removal and availability of both baseline and ≥2 subsequent serum GMI measurements after starting antifungal therapy (if available). Serum GMI was assessed by direct double-sandwich enzyme-linked immunosorbent assay with reference to positive and negative control samples. Comparisons of categorical variables among groups were analyzed by Fisher's exact test for categorical data and the Wilcoxon rank-sum test for continuous variables. Mortality outcomes were analyzed by survival analyses using Kaplan-Meier curves with Log-rank test. Results: Seventy-six (46%) of 166 participants from 21 PD centers between 2018 and 2022 were included. The median age was 58 (50-65) years, and a half of the patients (50%) had type II diabetes. Nineteen (25%) and 57 (75%) episodes were caused by yeast and mold, respectively. Death occurred in 11 (14%) patients at 3 months, and no differences were observed in demographics, laboratories, treatment characteristics, or in baseline serum GMI between those who died and those who survived. Serum GMI progressively declined over the follow-up period after the completion of treatment. Patients who died had significantly higher posttreatment serum GMI levels and were more likely to have positive GMI after treatment. Conclusion: Serum GMI is an excellent biomarker for risk stratification and treatment response monitoring in patients on PD with fungal peritonitis.

Intractable ascites in a female receiving hemodialysis.

We report a case of a 60-year-old female who presented with intractable ascites 2 months after switching from peritoneal dialysis (PD) to hemodialysis (HD) due to an episode of refractory culture-negative peritonitis (CNP). Abdominal paracentesis yielded inflammatory ascites, which later grew Cladosporium cladosporioides, establishing the diagnosis of fungal peritonitis. She was successfully treated with a 4-week course of oral voriconazole. Cladosporium spp. are common fungi in the environment but rarely cause PD-associated peritonitis and can be challenging to diagnose with conventional microbiologic evaluation. In summary, PD-associated peritonitis can worsen after a patient switches to HD. Therefore, it is essential to maintain a high level of suspicion for such complications related to their previous dialysis modality to arrive at an accurate diagnosis.

A Case of Extranodal NK/T-cell Lymphoma Infiltrating Kidneys, Presenting With Hematuria and Proteinuria With False-Positive Serum Anti-proteinase 3, and Mimicking Granulomatosis With Polyangiitis.

We report a case of misdiagnosed extranodal NK/T-cell lymphoma, nasal type, mimicking granulomatosis with polyangiitis (GPA). A 30-year-old male presented with chronic non-resolving right paranasal sinusitis for two years accompanied by multiple generalized cutaneous nodules, and subnephrotic-range proteinuria. Biopsies from skin lesions and paranasal sinuses demonstrated leukocytoclastic vasculitis and necrotizing granulomatous inflammation, respectively. Serum proteinase 3 (PR3)-antineutrophilic cytoplasmic antibody (ANCA) was positive, suggesting the diagnosis of GPA based on the 2022 American College of Rheumatology/European Alliance of Associations for Rheumatology Classification Criteria for GPA. A kidney biopsy was not pursued due to the cause of glomerulonephritis (GN) being clinically evident, per the KDIGO 2021 GN Clinical Practice Guidelines. Immunosuppression was administered, which led to a transient improvement in clinical symptoms. However, subsequent kidney biopsy and other organ biopsies with cytogenic and molecular tests eventually confirmed extranodal NK/T-cell lymphoma infiltrating kidneys, skin, and paranasal sinuses. Physicians should always consider the possibility of hematologic malignancy in young adults presenting with multiple-organ involvement with vasculitic lesions or pauci-immune crescentic GN, albeit positive ANCA serologies. Kidney biopsy with cytogenic support should be performed to exclude threatening diseases, especially in atypical cases such as in young patients despite a context of compatible manifestations with other syndromes.