In vivo base editing rescues primary hyperoxaluria type 1 in rats.

Primary hyperoxaluria type 1 (PH1) is a childhood-onset autosomal recessive disease, characterized by nephrocalcinosis, multiple recurrent urinary calcium oxalate stones, and a high risk of progressive kidney damage. PH1 is caused by inherent genetic defects of the alanine glyoxylate aminotransferase (AGXT) gene. The in vivo repair of disease-causing genes was exceedingly inefficient before the invention of base editors which can efficiently introduce precisely targeted base alterations without double-strand DNA breaks. Adenine base editor (ABE) can precisely convert A·T to G·C with the assistance of specific guide RNA. Here, we demonstrated that systemic delivery of dual adeno-associated virus encoding a split-ABE8e could artificially repair 13% of the pathogenic allele in AgxtQ84X rats, a model of PH1, alleviating the disease phenotype. Specifically, ABE treatment partially restored the expression of alanine-glyoxylate-aminotransferase (AGT), reduced endogenous oxalate synthesis and alleviated calcium oxalate crystal deposition. Western blot and immunohistochemistry confirmed that ABE8e treatment restored AGT protein expression in hepatocytes. Moreover, the precise editing efficiency in the liver remained stable six months after treatment. Thus, our findings provided a prospect of in vivo base editing as a personalized and precise medicine for PH1 by directly correcting the mutant Agxt gene.

Ureterocele with duplex collecting systems and febrile urinary tract infection risk.

PURPOSE: Ureterocele has been hypothesized to be the risk factor for febrile urinary tract infections (F-UTIs) in patients with duplex collecting systems, but this has not been proved, and our goal was to assess the relation between ureterocele with duplex collecting systems and F-UTIs. METHODS: We included individual-participant data from patients seen for complicated duplex collecting systems from 2010 to 2020 retrospectively followed. Those with using continuous low-dose antibiotic prophylaxis and incompletely duplicated systems were removed from the study. The participants were divided into two cohorts according to patients with or without ureterocele. The primary endpoint of this study was recurrent F-UTIs. RESULTS: We analyzed medical reports of 300 patients, of which 75% were female. Among the 300 patients, F-UTIs developed in 111/159 (69.8%) patients in the ureterocele group and in 69/141 (48.9%) patients in the no-ureterocele group. Univariate analysis found no discernible difference except in grade of hydronephrosis between ureterocele group and no-ureterocele group. Moreover, Cox proportional regression analysis revealed that patients of duplex system ureterocele might be intrinsically more prone to develop F-UTIs (adjusted hazard ratio 1.894; 95% CI 1.412-2.542; p  <  0.001). CONCLUSION: Among participants with duplex systems, the risk of recurrent F-UTIs in patients with ureterocele was higher than patients without it, and mini-invasive surgical correction should be considered at young age to reduce F-UTIs.

Predictive Factors of Contralateral Operation after Initial Pyeloplasty in Children with Antenatally Detected Bilateral Hydronephrosis Due to Ureteropelvic Junction Obstruction.

OBJECTIVES: This study was performed to analyze the predictive factors of a contralateral operation after initial pyeloplasty in patients with antenatally detected bilateral ureteropelvic junction obstruction. METHODS: Patients with prenatally diagnosed bilateral ureteropelvic junction obstruction who underwent initial pyeloplasty (aged <12 months at initial pyeloplasty) were offered to participate in the study. Patients were recruited from January 2012 to December 2015. The anteroposterior renal pelvic diameter, parenchymal thickness, and calyceal dilatation were evaluated. Predictive factors of contralateral pyeloplasty after initial unilateral pyeloplasty were also examined. RESULTS: In total, 82 patients were included in the study (mean age, 2.8 months). Among all patients who underwent initial pyeloplasty, additional contralateral pyeloplasty was required in 11 patients (13.4%). The outcome of contralateral hydronephrosis was assessed as resolution, persistence, or surgery. The median anteroposterior renal pelvic diameter and calyceal dilatation were significantly different among the groups (p < 0.001). Calyceal dilatation of ≥10 mm and a calyceal dilatation/parenchymal thickness ratio of ≥5 strongly suggested the likelihood of a contralateral operation. CONCLUSIONS: In most patients with bilateral ureteropelvic junction obstruction, improvement or resolution of contralateral hydronephrosis following initial unilateral pyeloplasty can be expected. Patients with contralateral calyceal dilatation >10 mm and the calyceal dilatation/parenchymal thickness ratio >5 are at higher risk of surgery.

Lipid nanoparticle-mediated base-editing of the Hao1 gene achieves sustainable primary hyperoxaluria type 1 therapy in rats.

Primary hyperoxaluria type 1 (PH1) is a severe hereditary disease, leading to the accumulation of oxalate in multiple organs, particularly the kidney. Hydroxyacid oxidase 1 (HAO1), a pivotal gene involved in oxalate production, is an approved target for the treatment of PH1. In this study, we demonstrated the discovery of several novel therapeutic sites of the Hao1 gene and the efficient editing of Hao1 c.290-2 A in vivo with lipid nanoparticles (LNP) delivered adenine base editing (ABE) mRNA. A single infusion of LNP-ABE resulted in a near-complete knockout of Hao1 in the liver, leading to the sustainable normalization of urinary oxalate (for at least 6 months) and complete rescue of the patho-physiology in PH1 rats. Additionally, a significant correlation between Hao1 editing efficiency and urinary oxalate levels was observed and over 60% Hao1 editing efficiency was required to achieve the normalization of urinary oxalate in PH1 rats. These findings suggest that the LNP-mediated base-editing of Hao1 c.290-2 A is an efficient and safe approach to PH1 therapy, highlighting its potential utility in clinical settings.

Differences in renal cortex transcriptional profiling of wild-type and novel type B cystinuria model rats.

Cystinuria is a genetic disorder of cystine transport that accounts for 1-2% of all cases of renal lithiasis. It is characterized by hyperexcretion of cystine in urine and recurrent cystine lithiasis. Defective transport of cystine into epithelial cells of renal tubules occurs because of mutations of the transport heterodimer, including protein b0,+AT (encoded by SLC7A9) and rBAT (encoded by SLC3A1) linked through a covalent disulfide bond. Study generated a novel type B cystinuria rat model by artificially deleting 7 bp of Slc7a9 gene exon 3 using the CRISPR-Cas9 system, and those Slc7a9-deficient rats were proved to be similar with cystinuria in terms of genome, transcriptome, translation, and biologic phenotypes with no off-target editing. Subsequent comparisons of renal histopathology indicated model rats gained typical secondary changes as medullary fibrosis with no stone formation. A total of 689 DEGs (383 upregulated and 306 downregulated) were differentially expressed in the renal cortex of cystinuria rats. In accordance with the functional annotation of DEGs, the potential role of glutathione metabolism processes in the kidney of cystinuria rat model was proposed, and KEGG analysis results showed that knock-out of Slc7a9 gene triggered more biological changes which has not been studied. In short, for the first time, a rat model and its transcriptional database that mimics the pathogenesis and clinical consequences of human type B cystinuria were generated.

The clinical manifestations of intermittent hydronephrosis and their relationship with renal function in pediatric patients.

BACKGROUND AND OBJECTIVE: Most patients with intermittent hydronephrosis have preserved differential renal function (DRF), while others already have impaired DRF at diagnosis. We summarized the clinical manifestations of intermittent hydronephrosis to elucidate what may be related to DRF loss. STUDY DESIGN: We retrospectively reviewed patients presenting to our department with unilateral Dietl's Crisis between January 2014 and December 2017. Clinical characteristics were collected, including age of first onset, time of onset, duration of the longest single episodes and whether the patient had prenatally detected hydronephrosis. Ultrasonographic (US) parameters included anteroposterior diameter (APD) during the symptomatic and asymptomatic period. Dynamic renograms (DR) were reviewed to obtain preoperative DRF. RESULTS: A total of 150 patients met the selective criteria. Of the 128 patients whose mother had regular obstetric ultrasounds during pregnancy, 50 (39.06%) had prenatally detected pelvic dilation. The mean age of the first attack was earlier in the prenatally detected hydronephrosis group than in the postnatally detected group (4.58 vs 5.87, p = 0.002). The mean preoperative DRF was 41.03% in all of the patients. The patients whose DRFs were below 40% had longer durations of single attacks than those over 40%. The former group also had larger APD during the symptomatic periods than the latter group. The risk of DRF < 40% was higher in the patients whose APD at attack was greater than 35 mm (OR=5.111, χ2=12.899, p < 0.001). The attack times, waiting time before the surgery and age of the first onset had no association with preoperative DRF. DISCUSSION: Our study first found that in patients with Dietl's Crisis, the APD during the symptomatic periods and the longest duration of the attack were associated with DRF loss. But the retrospective nature of our study limited us to understand the relationship between DRF and total duration of all attacks. CONCLUSION: This study revealed that children with prenatal hydronephrosis could develop Dietl's Crisis at early ages. A longer duration of attack and larger APD during the attack were associated with impaired DRF.

Quantitative Proteome of Infant Stenotic Ureters Reveals Extracellular Matrix Organization and Oxidative Stress Dysregulation Underlying Ureteropelvic Junction Obstruction.

PURPOSE: Ureteropelvic junction obstruction (UPJO) is the most frequent cause of congenital hydronephrosis in child. To better investigate the molecular mechanisms of this pathological process, the stenotic ureter proteome of UPJO in infants is compared with their own normal pre-stenotic segments. EXPERIMENTAL DESIGN: Data independent acquisition-based proteomics are performed to compare proteome between pre-stenotic and stenotic ureter from nine UPJO infants. Gene ontology analysis, hierarchical cluster analysis, and network interaction are performed to characterize biological functions of significantly altered proteins. Selected significantly altered proteins are validated by western blot on another three UPJO infants. RESULTS: 15 proteins are up-regulated and 33 proteins are down-regulated during stenotic pathology. Significantly altered proteins are involved in decreased extracellular matrix and cytoskeleton organization, increased regulation of oxidative activity, and altered inflammatory associated exocytosis. Significant expression of biglycan, fibulin-1, myosin-10, cytochrome b5 are validated providing possible mechanism in UPJO which could be associated impaired smooth muscle cell, epithelial integrity, and increased oxidative stress. CONCLUSIONS AND CLINICAL RELEVANCE: This study provides molecular evidence of dysregulated extracellular matrix organization, impaired smooth muscle cell, and oxidative stress during UPJO pathology, indicating that biglycan, fibulin-1, myosin-10, cytochrome b5 might reflect the pathology of UPJO.

Quantitative Urinary Proteome Reveals Potential Biomarkers for Ureteropelvic Junction Obstruction.

PURPOSE: Ureteropelvic junction obstruction (UPJO) is a common obstructive disease. To investigate useful urinary biomarkers in UPJO children, the urinary proteome in UPJO infants is analyzed and it is compared with normal controls. EXPERIMENTAL DESIGN: A tandem mass tag (TMT)-based quantitative proteomics study is performed to analyze the proteome of bladder urine (BU) and pelvis urine (PU) from unilateral UPJO infants with differential renal function less than 40% and they are compared with normal control urine (CON). GO analysis is then utilized to analyze general characterization of the proteins. Proteomic results are verified by western blot. RESULTS: There are 81 and 186 proteins significantly changed in BU and PU groups, respectively, as compared to the CON group. Fifty proteins overlaps are found between these two sets of statistically significant differential proteins. These 50 common differential proteins are involved in multiple biological processes. The increased urinary abundance of Fetuin-A, AGP1, AGP2, Alpha-1-microglobulin/Bikunin Precursor (AMBP), and prostaglandin-H2D-isomerase (PGDS) are verified by western blot analysis. CONCLUSIONS AND CLINICAL RELEVANCE: This proteomic analysis indicates that urinary Fetuin-A, AGP1, AGP2, protein AMBP, and PGDS may serve as noninvasive potential biomarkers and these proteins can help to further yield pathological mechanisms involved in UPJO.

Congenital Stenosis of the External Orifice of the Urethra in a Female Child.

Limited numbers of pediatric stenosis of the external orifice of the urethra have been reported. We report a case of congenital stenosis of the external orifice of the urethra in a female child who underwent meatoplasty. As an initial strategy for congenital stenosis of the external orifice of the urethra in girls, dilatation of the stenosed urethral meatus may be another management of choice.

Repair of Urethrovaginal Fistula Secondary to Pelvic Fracture With a Labia Minora Skin Flap in Young Girls.

The study aims to evaluate the efficacy of transpubic access using a pedicle flap from the labia minora for urethral reconstruction in young girls with urethrovaginal fistula secondary to pelvic fracture. Between January 2011 and January 2016, 4 cases of traumatic urethrovaginal fistula in young girls were treated using a pedicle flap from the labia minora. The mean follow-up was 27 months. All patients voided well and achieved normal urinary control. One patient had recurrent urethrovaginal fistula. The remaining 3 patients required no additional treatment. A labia minora skin flap for urethral reconstruction in young girls with urethrovaginal fistula secondary to pelvic fractures is a reliable technique.

An initial differential renal function between 35% and 40% has greater probability of leading to normal after pyeloplasty in patients with unilateral pelvic-ureteric junction obstruction.

PURPOSE: We compared the outcomes in patients who were <1 year old and had hydronephrosis with SFU grade 3-4 PUJ obstruction to observe the potential recovery of renal morphology and DRF after successful pyeloplasty. METHODS: All children younger than 1 year old with SFU grade 3-4 PUJ obstruction from January 2013 to June 2015 were retrospectively analyzed. A total of 92 children were grouped according to their DRF value at pyeloplasty as follows: DRF from 30 to ≤35% (group I) and DRF from 35 to ≤40% (group II). We evaluated changes in anteroposterior diameter and differential renal function using ultrasound and diuretic renography. Outcomes were compared using Student t test. RESULTS: Group I comprised 45 patients, and group II included 47 patients. No significant difference was observed in the initial APD, final APD and the improvement of APD after pyeloplasty between two groups. Significant differences were observed between the initial and final DRF values in both groups. The difference in DRF improvement after pyeloplasty between groups I and II was significant. The DRF improved to a normal stage significantly more frequently in group II (21/47; 44.7%) than in group I (13/45; 28.9%). CONCLUSION: The improvement in DRF after pyeloplasty was significant for patients with an initial DRF from 30 to ≤35%. However, patients with an initial DRF from 35 to ≤40% had a greater probability of achieving normal renal function. Patients with severely impaired initial renal function had a marginal probability of achieving a normal value.