Targeted phasing of 2-200 kilobase DNA fragments with a short-read sequencer and a single-tube linked-read library method.

In the human genome, heterozygous sites refer to genomic positions with a different allele or nucleotide variant on the maternal and paternal chromosomes. Resolving these allelic differences by chromosomal copy, also known as phasing, is achievable on a short-read sequencer when using a library preparation method that captures long-range genomic information. TELL-Seq is a library preparation that captures long-range genomic information with the aid of molecular identifiers (barcodes). The same barcode is used to tag the reads derived from the same long DNA fragment within a range of up to 200 kilobases (kb), generating linked-reads. This strategy can be used to phase an entire genome. Here, we introduce a TELL-Seq protocol developed for targeted applications, enabling the phasing of enriched loci of varying sizes, purity levels, and heterozygosity. To validate this protocol, we phased 2-200 kb loci enriched with different methods: CRISPR/Cas9-mediated excision coupled with pulse-field electrophoresis for the longest fragments, CRISPR/Cas9-mediated protection from exonuclease digestion for mid-size fragments, and long PCR for the shortest fragments. All selected loci have known clinical relevance: BRCA1, BRCA2, MLH1, MSH2, MSH6, APC, PMS2, SCN5A-SCN10A, and PKI3CA. Collectively, the analyses show that TELL-Seq can accurately phase 2-200 kb targets using a short-read sequencer.

Clinicopathological prognostic stratification for proteinuria and kidney survival in IgA nephropathy: a Japanese prospective cohort study.

Background: We require a clinicopathological risk stratification method for immunoglobulin A nephropathy (IgAN) to predict kidney outcomes. We examined a renal failure risk group (RF-RG) classification system created following a prior multicentre, retrospective study to determine if RF-RG could predict kidney outcomes. Methods: We collected data from Japanese patients with IgAN registered between 1 April 2005 and 31 August 2015. The primary outcome was a composite 50% increase in serum creatinine from baseline or dialysis induction. The secondary outcomes were times to proteinuria remission (ProR) and haematuria remission (HemR). Results: The enrolled 991 patients from 44 facilities were followed for a median of 5.5 years (interquartile range 2.5-7.5), during which 87 composite events (8.8%) occurred. RF-RG was significantly associated with the primary outcome {hazard ratio [HR] II 2.78 [95% confidence interval (CI) 1.12-6.93], III 7.15 (2.90-17.6), IV 33.4 (14.1-79.0), I as a reference, P < .001}.The discrimination performance was good [C-statistic 0.81 (95% CI 0.76-0.86)] and the time-dependent C-statistics exceeded 0.8 over 10 years. Among the 764 patients with proteinuria and 879 patients with haematuria at baseline, 515 and 645 patients showed ProR and HemR, respectively. ProR was significantly less frequent in patients with advanced disease [subdistribution HR: II 0.79 (95% CI 0.67-0.94), III 0.53 (0.41-0.66), IV 0.15 (0.09-0.23), I as a reference, P < .001]. We also observed an association between HemR and RF-RG. Conclusions: RF-RG demonstrated good predictive ability for kidney outcomes.

A Pragmatic Method to Integrate Data From Preexisting Cohort Studies Using the Clinical Data Interchange Standards Consortium (CDISC) Study Data Tabulation Model: Case Study.

Background: In recent years, many researchers have focused on the use of legacy data, such as pooled analyses that collect and reanalyze data from multiple studies. However, the methodology for the integration of preexisting databases whose data were collected for different purposes has not been established. Previously, we developed a tool to efficiently generate Study Data Tabulation Model (SDTM) data from hypothetical clinical trial data using the Clinical Data Interchange Standards Consortium (CDISC) SDTM. Objective: This study aimed to design a practical model for integrating preexisting databases using the CDISC SDTM. Methods: Data integration was performed in three phases: (1) the confirmation of the variables, (2) SDTM mapping, and (3) the generation of the SDTM data. In phase 1, the definitions of the variables in detail were confirmed, and the data sets were converted to a vertical structure. In phase 2, the items derived from the SDTM format were set as mapping items. Three types of metadata (domain name, variable name, and test code), based on the CDISC SDTM, were embedded in the Research Electronic Data Capture (REDCap) field annotation. In phase 3, the data dictionary, including the SDTM metadata, was outputted in the Operational Data Model (ODM) format. Finally, the mapped SDTM data were generated using REDCap2SDTM version 2. Results: SDTM data were generated as a comma-separated values file for each of the 7 domains defined in the metadata. A total of 17 items were commonly mapped to 3 databases. Because the SDTM data were set in each database correctly, we were able to integrate 3 independently preexisting databases into 1 database in the CDISC SDTM format. Conclusions: Our project suggests that the CDISC SDTM is useful for integrating multiple preexisting databases.

In vivo transfection of cytokine genes into tumor cells using a synthetic vehicle promotes antitumor immune responses in a visceral tumor model.

The tumor microenvironment (TME) strongly affects the clinical outcomes of immunotherapy. This study aimed to activate the antitumor immune response by manipulating the TME by transfecting genes encoding relevant cytokines into tumor cells using a synthetic vehicle, which is designed to target tumor cells and promote the expression of transfected genes. Lung tumors were formed by injecting CT26.WT intravenously into BALB/c mice. Upon intravenous injection of the green fluorescent protein-coding plasmid encapsulated in the vehicle, 14.2% tumor-specific expression was observed. Transfection of the granulocyte-macrophage colony-stimulating factor (GM-CSF) and CD40 ligand (L)-plasmid combination and interferon gamma (IFNγ) and CD40L-plasmid combination showed 45.5% and 54.5% complete remission (CR), respectively, on day 60; alternate treatments with both the plasmid combinations elicited 66.7% CR, while the control animals died within 48 days. Immune status analysis revealed that the density of dendritic cells significantly increased in tumors, particularly after GM-CSF- and CD40L-gene transfection, while that of regulatory T cells significantly decreased. The proportion of activated killer cells and antitumoral macrophages significantly increased, specifically after IFNγ and CD40L transfection. Furthermore, the level of the immune escape molecule programmed death ligand-1 decreased in tumors after transfecting these cytokine genes. As a result, tumor cell-specific transfection of these cytokine genes by the synthetic vehicle significantly promotes antitumor immune responses in the TME, a key aim for visceral tumor therapy.

Associations of corticosteroid therapy and tonsillectomy with kidney survival in a multicenter prospective study for IgA nephropathy.

Efficacy of systemic corticosteroid therapy (CS) for long-term kidney survival in patients with IgA nephropathy (IgAN) is controversial. Therefore, prospective studies evaluating targeted therapies to lymphatic tissues in mucosal immune system responsible for production of nephritogenic IgA have been desired worldwide. Here, we aimed to evaluate the associations of CS and combination therapy of CS and tonsillectomy (CS + Tx) with kidney survival, using database from a nationwide multicenter prospective cohort study on IgAN. Primary outcome was a 50% increase in serum creatinine from baseline or dialysis induction. The analysis included 941 patients (CS/CS + Tx/non-CS 239/364/338), 85 (9.0%) of whom reached outcomes during median follow-up of 5.5 (interquartile range 2.0-8.0) years. On overlap weighting analysis with balanced baseline characteristics, CS and CS + Tx were associated with lower risk of kidney events when compared with non-CS (hazard ratio [HR] 0.51, 95% confidence interval [CI] 0.29-0.88 and HR 0.20, 95%CI 0.09-0.44, respectively). Notably, when compared with the CS, CS + Tx was associated with a lower risk of kidney events (HR 0.40, 95%CI 0.18-0.91). Present study demonstrated, keeping with favorable association of systemic CS with kidney survival, concurrent tonsillectomy as one of targeted interventions to lymphatic tissues may provide additional improvement to kidney survival in patients with IgAN.

A Pragmatic Method to Integrate Data from Pre-existing Cohort Studies using the Clinical Data Interchange Standards Consortium (CDISC) Study Data Tabulation Model: Practical use of REDCap2SDTM.

BACKGROUND: In recent years, many researchers have focused on legacy data utilization, such as pooled analyses that collect and re-analyze data from multiple studies. However, the methodology for the integration of pre-existing databases whose data were collected for different purposes has not been established. Previously, we developed a tool to efficiently generate Study Data Tabulation Model (SDTM) data from hypothetical clinical trial data using the Clinical Data Interchange Standards Consortium (CDISC) SDTM. OBJECTIVE: To design a practical model for integrating pre-existing databases using the CDISC SDTM. METHODS: Data integration was performed in three phases: i) confirmation of the variables, ii) SDTM mapping, and iii) generation of the SDTM data. In phase 1, the definitions of the variables in detail were confirmed, and the datasets were converted to vertical datasets. In phase 2, the items derived from the SDTM format were set as mapping items. Three types of metadata (domain name, variable name, and test code), based on the CDISC SDTM, were embedded in the REDCap field annotation. In phase 3, the data dictionary, including the SDTM metadata, were output in the Operational Data Model (ODM) format. Finally, the mapped SDTM were generated using REDCap2SDTM v2. RESULTS: SDTM data were generated as a comma-separated values file for each of the seven domains defined in the metadata. Twenty-two items were commonly mapped to three databases. Because the SDTM data were set in each database correctly, we were able to integrate three independently pre-existing databases into one database in the CDISC SDTM format. CONCLUSIONS: Our project suggests that the CDISC SDTM is useful for integrating multiple pre-existing databases.

Granulomatosis with polyangiitis presenting as a solitary renal mass: a case report.

BACKGROUND: Granulomatosis with polyangiitis (GPA) is characterized by necrotizing granulomatous vasculitis involving small-sized vessels in the upper airways, lower airways, and kidneys. Renal pathology is usually characterized by focal segmental necrotizing glomerulonephritis, which often leads to rapidly progressive renal failure. This type of renal involvement is usually unapparent on radiography. The presence of a renal mass in a patient with GPA, although extremely rare, is recognizable. Herein, we report a rare case of GPA presenting as a solitary renal mass and present a review of the literature. CASE PRESENTATION: A 75-year-old woman presented with a solitary right kidney mass measuring 4 × 3.5 cm detected by enhanced computed tomography. There was no history of sinusitis, rhinitis, cough, or pneumonia suggestive of systemic GPA. Nephrectomy was performed based on the suspicion of renal cell carcinoma or malignant lymphoma. Three months later, she was admitted because her serum creatinine levels increased from 54.81 µmol/L to 405.76 µmol/L accompanied by a high C-reactive protein level of 159 mg/L. Anti-neutrophil cytoplasmic antibodies against myeloperoxidase and anti-proteinase 3 were negative. Histological examinations of the solitary renal mass revealed necrotizing granulomatous arteritis in the cortex and medullary vasa recta, surrounded by interstitial fibrosis, and focal segmental necrotizing glomerulonephritis in the localized lesion; however, signs of vasculitis were not observed in areas other than the solitary mass. Therefore, the patient was diagnosed with granulomatosis with polyangiitis (GPA). Despite treatment with prednisolone (30 mg/day), the patient developed oliguria with an elevation of her serum creatinine level to 583.44 µmol/L, which required hemodialysis within one month after the initiation of steroid therapy. The patient could successfully discontinue hemodialysis 21 months later, following a decrease in her serum creatinine level to 251.06 µmol/L. CONCLUSIONS: GPA should be considered as one of the differential diagnoses of a solitary renal mass. Furthermore, patients with solitary renal masses associated with GPA may exhibit a favorable response to steroid or immunosuppressive treatment.

Targeted Phasing of 2-200 Kilobase DNA Fragments with a Short-Read Sequencer and a Single-Tube Linked-Read Library Method.

In the human genome, heterozygous sites are genomic positions with different alleles inherited from each parent. On average, there is a heterozygous site every 1-2 kilobases (kb). Resolving whether two alleles in neighboring heterozygous positions are physically linked-that is, phased-is possible with a short-read sequencer if the sequencing library captures long-range information. TELL-Seq is a library preparation method based on millions of barcoded micro-sized beads that enables instrument-free phasing of a whole human genome in a single PCR tube. TELL-Seq incorporates a unique molecular identifier (barcode) to the short reads generated from the same high-molecular-weight (HMW) DNA fragment (known as 'linked-reads'). However, genome-scale TELL-Seq is not cost-effective for applications focusing on a single locus or a few loci. Here, we present an optimized TELL-Seq protocol that enables the cost-effective phasing of enriched loci (targets) of varying sizes, purity levels, and heterozygosity. Targeted TELL-Seq maximizes linked-read efficiency and library yield while minimizing input requirements, fragment collisions on microbeads, and sequencing burden. To validate the targeted protocol, we phased seven 180-200 kb loci enriched by CRISPR/Cas9-mediated excision coupled with pulse-field electrophoresis, four 20 kb loci enriched by CRISPR/Cas9-mediated protection from exonuclease digestion, and six 2-13 kb loci amplified by PCR. The selected targets have clinical and research relevance (BRCA1, BRCA2, MLH1, MSH2, MSH6, APC, PMS2, SCN5A-SCN10A, and PKI3CA). These analyses reveal that targeted TELL-Seq provides a reliable way of phasing allelic variants within targets (2-200 kb in length) with the low cost and high accuracy of short-read sequencing.

Prognostic factors of IgA nephropathy presenting with mild proteinuria at the time of diagnosis (a multicenter cohort study).

BACKGROUND: Clinical factors affecting renal prognosis in patients with immunoglobulin A nephropathy (IgAN) and low urinary protein excretion (U-Prot) remain unclear. This study evaluated such factors in patients with clinical grade I (CG-I) IgAN with U-Prot < 0.5 g/day. METHODS: This secondary analysis of a previous retrospective study included 394 patients with CG-I IgAN. The primary outcome was the first occurrence of a 1.5-fold increase in serum creatinine levels from baseline. Factors related to renal prognosis were examined using univariate and multivariate Cox regression analyses. CG-I was divided into C-Grade Ia (CG-Ia) (n = 330) with baseline eGFR ≥ 60 ml/min/1.73 m2, and C-Grade Ib (CG-Ib) (n = 64) with baseline eGFR < 60 ml/min/1.73 m2. Outcome incidence was compared between conservative and aggressive therapy (corticosteroids and/or tonsillectomy) groups. RESULTS: Overall outcome incidence was significantly higher in CG-Ib than in CG-Ia; the cumulative incidence was significantly higher in CG-Ib (hazard ratio, 9.67; 95% confidence interval, 2.90-32.23). Older age, higher IgA levels, eGFR < 60 mL/min/1.73 m2, lower eGFR at baseline were independent prognostic factors for CG-I. Older age, lower eGFR, higher IgA levels at baseline, and U-Prot remission at 1-year post-diagnosis were independent prognostic factors for CG-Ib. Aggressive therapy tended to suppress the cumulative outcome incidence compared with conservative therapy in CG-Ib (p = 0.087). CONCLUSION: An eGFR < 60 mL/min/1.73 m2 is a significant predictor of renal prognosis in patients with IgAN and U-Prot < 0.5 g/day.

A Pregnant Woman with IgA Nephropathy Showing Histological Preeclampsia Findings without Hypertension Treated with Steroids: A Case Report and Literature Review.

A 35-year-old woman pregnant with twins developed nephrotic syndrome (NS) at 33 weeks' gestation, but her blood pressure remained within the normal range throughout gestation and puerperium. At 34 weeks' gestation, she delivered healthy twins via Caesarean section. After delivery, she developed massive proteinuria (21.1 g/day) and severe hypoalbuminemia (1.0 g/dL). A renal biopsy performed 19 days after delivery revealed IgA nephropathy (IgAN) and preeclampsia. She was treated with steroids, and the NS gradually resolved. This is a rare case of massive gestational proteinuria with IgAN and preeclampsia pathologically that did not meet the clinical criteria for preeclampsia.

Structural modeling for Oxford histological classifications of immunoglobulin A nephropathy.

In immunoglobulin A nephropathy (IgAN), Cox regression analysis can select independent prognostic variables for renal functional decline (RFD). However, the correlation of the selected histological variables with clinical and/or treatment variables is unknown, thereby making histology-based treatment decisions unreliable. We prospectively followed 946 Japanese patients with IgAN for a median of 66 mo. and applied structural equation modeling (SEM) to identify direct and indirect effects of histological variables on RFD as a regression line of estimated glomerular filtration rate (eGFR) via clinical variables including amount of proteinuria, eGFR, mean arterial pressure (MAP) at biopsy, and treatment variables such as steroid therapy with/without tonsillectomy (ST) and renin-angiotensin system blocker (RASB). Multi-layered correlations between the variables and RFD were identified by multivariate linear regression analysis and the model's goodness of fit was confirmed. Only tubular atrophy/interstitial fibrosis (T) had an accelerative direct effect on RFD, while endocapillary hypercellularity and active crescent (C) had an attenuating indirect effect via ST. Segmental sclerosis (S) had an attenuating indirect effect via eGFR and mesangial hypercellularity (M) had accelerative indirect effect for RFD via proteinuria. Moreover, M and C had accelerative indirect effect via proteinuria, which can be controlled by ST. However, both T and S had additional indirect accelerative effects via eGFR or MAP at biopsy, which cannot be controlled by ST. SEM identified a systemic path links between histological variables and RFD via dependent clinical and/or treatment variables. These findings lead to clinically applicable novel methodologies that can contribute to predict treatment outcomes using the Oxford classifications.

Ratio of serum creatinine to cystatin C is related to leg strength in predialysis CKD patients.

BACKGROUND AND OBJECTIVES: Chronic kidney disease (CKD) patients have lower levels of physical function. Especially, leg strength is important for daily living and preventing falls. However, physical function screenings are difficult to perform at clinical sites. To find clinically useful method to evaluate physical function in predialysis CKD patients, we tried to evaluate the relationship between the ratio of serum creatinine to serum cystatin C (Cre/CysC), and knee extensor muscle strength/body weight (KEMS) which reflects their leg strength. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We recruited 147 outpatients with CKD (87 men; mean age, 61.6 ± 9.8 years; mean eGFRcreat, 40.7 ± 12.9 mL/min/1.73m2) in this cross-sectional study. KEMS was assessed using a wire strain gauge dynamometer. Skeletal muscle mass and body fat mass were assessed by bioelectrical impedance analysis. RESULTS: The mean value of Cre/CysC was 1.01 ± 0.18. The mean value of KEMS was 1.60 ± 0.47 Nm/kg. In multivariate linear regression analysis, skeletal muscle mass (p < 0.01), body fat mass (p < 0.01), hemoglobin (p = 0.01), and Cre/CysC (p < 0.01) was independently related to KEMS. The correlation between Cre/CysC and KEMS is stronger in high quantile of Cre/CysC. CONCLUSIONS: In predialysis CKD patients, KEMS showed lower as CKD stage advanced. Cre/CysC is significantly related to KEMS independently. Cre/CysC may be an alternative marker for leg strength in CKD patients and even more valuable to utilize in cases with high Cre/CysC.

Immunohistological score of transcription factor 21 had a positive correlation with its urinary excretion and proteinuria in immunoglobulin A nephropathy.

Transcription factor 21 (TCF21) contributes to mammalian nephrogenesis, and especially to glomerular maturation. Our previous study suggested its influence on glomerular injury, showing that TCF21 expression in podocytes had a positive correlation with the urinary protein value and also with the urinary TCF21 concentration. We now focus on its influence on the clinical course of immunoglobulin A nephropathy (IgAN), as patients with IgAN constitute the largest population of individuals with primary chronic glomerulonephritis in the world. Twenty cases of IgAN were divided into two groups according to the immunohistological score (IHS) of glomerular TCF21 expression: group IHS1 (n=7) and group IHS2+3 (n=13). Sixteen of the 20 cases were followed up for 2 years. Group IHS2+3 had heavier urinary protein (p=0.03) and a greater urinary TCF21 level (p<0.001) compared to group IHS1 at baseline. None of the other factors including hematuria, estimated glomerular filtration rate (eGFR), or the Oxford classification showed a statistically significant difference between these two groups. At the 2-year follow-up, even though the rate of remission in urinary protein, hematuria and the eGFR decline were not statistically correlated to IHS, the IHS2+3 group had a slight tendency toward a steeper eGFR decline compared to IHS1 (p=0.31). The present study suggested that the higher IHS of TCF21 corresponded to heavier proteinuria and a higher urinary TCF21 level in IgAN. This could be the first step in determining the TCF21 value for predicting the prognosis for IgAN.

Utility of remission criteria for the renal prognosis of IgA nephropathy.

BACKGROUND: Novel criteria for the remission of Immunoglobulin A nephropathy (IgAN) based on an opinion survey of Japanese nephrologists and literature review were proposed in 2013. This single-center, longitudinal retrospective cohort study was conducted to validate this criteria. METHODS: Present study included the IgAN patients diagnosed between 2001 and 2005 in the Juntendo University Hospital. Remission of hematuria was defined as three consecutive dipstick test results of ( -) to ( ±) or a red blood cell count < 5 in urinary sediment per high-power field during at least 6 months. Remission of proteinuria was defined as three consecutive dipstick results of ( -) to ( ±) during at least 6 months. We categorized four groups according to the remission status which was assessed 2 years after the renal biopsy. The primary outcome was a 50% increase in the serum creatinine over the baseline. We evaluated the slope of eGFR decline (mL/min/1.73 m2/year) and a decrease in the eGFR of 30% from baseline eGFR as the secondary outcome, respectively. RESULTS: A total of 74 patients (male: 47.3%, median age: 30 years) were included and were followed for a median of 86.5 months. During the period, forty-one patients achieved neither remission of proteinuria nor hematuria (NR). Twelve patients met the primary study outcome. A survival analysis revealed that the NR had the worst prognosis and the steepest slope of eGFR decline. CONCLUSION: Although further validation in a large cohort is necessary, these novel remission criteria for IgAN patients appear to predict the renal prognosis.

A cross-sectional study in patients with IgA nephropathy of correlations between clinical data and pathological findings at the time of renal biopsy: a Japanese prospective cohort study.

BACKGROUND: The correlations between clinical data and pathological findings at the time of renal biopsy were investigated in IgA nephropathy patients. METHODS: 771 patients diagnosed with IgA nephropathy by renal biopsy were enrolled. The correlations between clinical variables including eGFR, daily proteinuria, mean arterial pressure (MAP), serum uric acid (UA) values, and pathological parameters were examined. These patients were further divided into three groups: children (< 19 years old), young adults (19-60 years), and elderly patients (> 60 years). RESULTS: Daily proteinuria was moderately correlated with all pathological parameters (Rs = 0.23-0.49). The mesangial score, the percentage of glomeruli that contained endocapillary hypercellularity, cellular/fibrocellular crescents or tuft necrosis, and segmental glomerulosclerosis (GS) affected daily proteinuria most on multiple linear regression analysis (MLRA). eGFR, MAP, and serum UA levels were mainly correlated with the degree of GS and interstitial lesions. In children, the degree of cellular/fibrocellular crescents or tuft necrosis was correlated with not only daily proteinuria, but also decreased eGFR (Rs = 0.51, - 0.24). Endocapillary hypercellularity was the only independent variable related to daily proteinuria on MLRA. CONCLUSION: In all age cohorts of IgA nephropathy patients, daily proteinuria was correlated with all histological parameters, including both acute and chronic glomerular lesions, and the mesangial score. Independent variables for daily proteinuria were the meangial score, acute histological lesions, and segmental GS on MLRA, whereas the remaining independent variable in the pediatric group was endocapillary hypercellurality. The clinical pathological correlation at the time of biopsy varied depending on the age group.

Membranous nephropathy with thrombotic microangiopathy-like lesions successfully treated with tocilizumab in a patient with idiopathic multicentric Castleman disease.

Idiopathic multicentric Castleman disease (iMCD) is a systemic lymphoproliferative disease involving multiple organs, including the kidneys. Membranous nephropathy (MN) has been rarely reported as a complication of iMCD. We herein report the case of a 48-year-old man with a 9-year history of iMCD that was complicated by treatment-resistant nephrotic syndrome due to MN. The first renal biopsy performed at the age of 45 years showed diffuse and global MN with a mild glomerular endothelial injury. He was treated with combined therapy of corticosteroids, immunosuppressants, and tocilizumab, an anti-interleukin-6 (IL-6) receptor monoclonal antibody, which was administered every 2-3 weeks. However, nephrotic syndrome persisted, and renal impairment slowly worsened. Serial biopsy performed at 3 years after the first biopsy confirmed advanced lesions of both MN-related and glomerular endothelial injuries. Modification of the therapeutic strategy to weekly administration of tocilizumab gradually led to the remission of proteinuria, allowing the termination of corticosteroids. Thus, the present case suggests a close link between excessive IL-6 actions and the development of glomerular lesions in iMCD. Successful treatment by strict inhibition of IL-6 actions, in this case, may provide a clue for deciding the therapeutic strategy for severe renal complications associated with iMCD.

Total Nephron Number and Single-Nephron Parameters in Patients with IgA Nephropathy.

Background: Single-nephron dynamics in progressive IgA nephropathy (IgAN) have not been studied. We applied novel methodology to explore single-nephron parameters in IgAN. Methods: Nonglobally sclerotic glomeruli (NSG) and globally sclerotic glomeruli (GSG) per kidney were estimated using cortical volume assessment via unenhanced computed tomography and biopsy-based stereology. Estimated single-nephron GFR (eSNGFR) and single-nephron urine protein excretion (SNUPE) were calculated by dividing eGFR and UPE by the number of NSG. Associations with CKD stage and clinicopathologic findings were cross-sectionally investigated. Results: This study included 245 patients with IgAN (mean age 43 years, 62% male, 45% on renin-angiotensin aldosterone system [RAAS] inhibitors prebiopsy) evaluated at kidney biopsy. CKD stages were 10% CKD1, 43% CKD2, 19% CKD3a, 14% CKD3b, and 14% CKD4-5. With advancing CKD stage, NSG decreased from mean 992,000 to 300,000 per kidney, whereas GSG increased from median 64,000 to 202,000 per kidney. In multivariable models, advancing CKD stage associated with lower numbers of NSG, higher numbers of GSG, and lower numbers of GSG + NSG, indicating potential resorption of sclerosed glomeruli. In contrast to the higher mean glomerular volume and markedly elevated SNUPE in advanced CKD, the eSNGFR was largely unaffected by CKD stage. Lower SNGFR associated with Oxford scores for endocapillary hypercellularity and crescents, whereas higher SNUPE associated with segmental glomerulosclerosis and tubulointerstitial scarring. Conclusions: SNUPE emerged as a sensitive biomarker of advancing IgAN. The failure of eSNGFR to increase in response to reduced number of functioning nephrons suggests limited capacity for compensatory hyperfiltration by diseased glomeruli with intrinsic lesions.

Renal Damage in Recurrent Atypical Hemolytic Uremic Syndrome Associated with C3 p.Ile1157Thr Gene Mutation.

Patients with atypical hemolytic uremic syndrome (aHUS) associated with a C3 p.Ile1157Thr mutation show a relatively high renal survival and low mortality rates, but renal histopathological findings after recurrence have been rarely reported. A 30-year-old man with a C3 p.Ile1157Thr mutation experienced a third recurrence of thrombotic microangiopathies with neurological and gastrointestinal disorders. A renal biopsy performed during the recovery phase of acute kidney injury revealed collapsed glomeruli and arteriolar vacuolization. Approximately 10% of glomeruli were globally sclerotic, despite the absence of arterio-/arteriolo-sclerosis. These findings suggest substantial progression of irreversible injuries in multiple organs, including kidneys, which occurs in aHUS patients with repeated thrombotic microangiopathies.

Impact of the number of steroid pulses in tonsillectomy combined with steroid pulse therapy: a nationwide retrospective study in Japan.

BACKGROUND: Steroid pulse therapy with tonsillectomy is known as a major treatment for IgA nephropathy (IgAN). However, its protocol was different among institutions and the effects of varying the number of steroid pulses remain unclear. METHODS: From a total of 1,174 IgAN patients in a multicenter retrospective cohort analysis in Japan, 195 patients were treated by tonsillectomy combined with corticosteroid. They were divided into four groups based on the number of administered steroid pulses from 0 to three (TSP0-3), and remission of urinary abnormalities and renal survival until 1.5-fold increase in serum creatinine level from baseline were analyzed among the four groups and between TSP1 and TSP3. RESULTS: Among the four groups, renal function was relatively good when the estimated glomerular filtration rate was approximately 80-90 mL/min/1.73m2 and proteinuria was relatively mild (< 1.0 g/gCre). The ratio of patients who developed renal dysfunction was < 5% in all groups, and the cumulative renal survival rate by Kaplan-Meier analysis was similar among groups (log-rank test, p = 0.37), despite varying clinical backgrounds and treatments. After adjustment of the background variables between TSP1 and TSP3, the remission rates of urinary abnormalities were similar and the renal survival rate also remained similar (66.8 vs. 85.4%, p = 0.45). CONCLUSIONS: In patients with mild proteinuria and good renal function, the number of steroid pulses did not affect the renal outcome in steroid pulse therapy with tonsillectomy. The adaptation and protocols, such as the number of steroid pulses, should be determined for each IgAN patient's background.