Ureteropelvic junction obstruction: diagnosis and management

The Inhibition of Fibrosis and Inflammation in Obstructive Kidney Injury via the miR-122-5p/SOX2 Axis Using USC-Exos

Background: Fibrosis and inflammation due to ureteropelvic junction obstruction substantially contributes to poor renal function. Urine-derived stem-cell-derived exosomes (USC-Exos) have therapeutic effects through paracrine. Methods: In vitro, the effects of USC-Exos on the biological functions of HK-2 and human umbilical vein endothelial cells were tested. Cell inflammation and fibrosis were induced by transforming growth factor-β1 and interleukin-1β, and their anti-inflammatory and antifibrotic effects were observed after exogenous addition of USC-Exos. Through high-throughput sequencing of microRNA in USC-Exos, the pathways and key microRNAs were selected. Then, the antifibrotic and anti-inflammatory effects of exosomal miR-122-5p and target genes were verified. The role of the miR-122-5p/SOX2 axis in anti-inflammatory and antifibrotic effects was verified. In vivo, a rabbit model of partial unilateral ureteral obstruction (PUUO) was established. Magnetic resonance imaging recorded the volume of the renal pelvis after modeling, and renal tissue was pathologically analyzed. Results: We examined the role of USC-Exos and their miR-122-5p content in obstructive kidney injury. These Exos exhibit antifibrotic and anti-inflammatory activities. SOX2 is the hub gene in PUUO and negatively related to renal function. We confirmed the binding relationship between miR-122-5p and SOX2. The anti-inflammatory and antifibrotic effects of miR-122-5p were inhibited, indicating that miR-122-5p has anti-inflammatory and antifibrotic effects by inhibiting SOX2 expression. In vivo, the PUUO group showed typical obstructive kidney injury after modeling. After USC-Exo treatment, the shape of the renal pelvis shown a remarkable improvement, and inflammation and fibrosis decreased. Conclusions: We confirmed that miR-122-5p from USC-Exos targeting SOX2 is a new molecular target for postoperative recovery treatment of obstructive kidney injury.

Our experience of operated pediatric ureteropelvic junction obstruction patients

AIMS

Ureteropelvic junction obstruction (UPJO) may originate from extrinsic or intrinsic causes in children. The aim of this study is to present preoperative and postoperative data of our patients operated for UPJO.

METHODS

A total of 64 patients who underwent open pyeloplasty were investigated retrospectively. They were evaluated in terms of demographically, clinics, hydronephrosis, differential renal functions (DRFs), half-time tracer clearance (½TC), and histopathologic results. Patients' numerical results were stated as mean ± standard deviation (SD).

RESULTS

Male gender was more prevalent (n = 47, 73.4%) and mean age at surgery was 46.87 months. UPJO was located at the left side in 56.3% (n = 36), and at the right side in 39.1% (n = 25) of patients. It was bilateral in 4.7% (n = 3). Hydronephrosis was found antenatally in 68.8% (n = 44) of patients. The mean preoperative DRF was 49.7% (21-78%) and mean postoperative DRF was 49.2% (20-56%). Mean renal scintigraphic t1/2 was >20 min for all patients. The mean AP diameter was 21.58 mm (10-62 mm). Muscular hypertrophy was the most common pathological finding, mean length of excised segment was 10.26 mm (3-40 mm). Crossing vessel (CV) was detected in 17.18% (n = 11). The CV was statistically associated with increased age of operation, left side, and female gender. Statistically significant hydronephrosis was found in non-CV patients. Re-operation was required in seven patients (7.8%).

CONCLUSIONS

Intrinsic pathologies are more seen in the etiology of UPJO patients with antenatal diagnosis and this group needs operation at an earlier age. However, CV is found more commonly in patients who are diagnosed and operated at older ages.

Robot-assisted pyeloplasty for ureteropelvic junction obstruction: initial experience with the novel avatera system

PURPOSE

This pilot study was designed to interpret the technically specific features of the avatera robotic system and present our initial experience with this novel platform in robot-assisted pyeloplasty (RAP).

METHODS

A single-center prospective study was conducted including all patients who underwent RAP with the avatera robotic system from June 2022 to October 2022 in our Department. Transperitoneal robot-assisted dismembered pyeloplasty was performed in all cases. The trocar placement and the surgical technique were similar in all patients. The successful completion of the procedures, operation time (including draping, docking and console time), decrease in hemoglobin postoperatively, and presence of any complications were the study's primary endpoints.

RESULTS

In total, nine patients underwent RAP using the avatera system. All procedures were successfully completed. The draping of the robotic unit was completed in a median time of 10 min (range 7-15), while the median docking time was 17 min (range 10-24). The median console time was 88 min (range 78-116) and no complications were noticed. The median hemoglobin drop was calculated to 0.7 g/dL (range 0.4-1). During the mean follow-up of 9.33 ± 2.78 months, no late postoperative complications were noticed.

CONCLUSION

The early outcomes of the use of the novel avatera system in RAP are presented. All operations were successfully completed with safety and efficacy, without complications or significant blood loss.

Comprehensive Proteomics Analysis Identifies CD38-Mediated NAD+ Decline Orchestrating Renal Fibrosis in Pediatric Patients With Obstructive Nephropathy

Obstructive nephropathy is one of the leading causes of kidney injury and renal fibrosis in pediatric patients. Although considerable advances have been made in understanding the pathophysiology of obstructive nephropathy, most of them were based on animal experiments and a comprehensive understanding of obstructive nephropathy in pediatric patients at the molecular level remains limited. Here, we performed a comparative proteomics analysis of obstructed kidneys from pediatric patients with ureteropelvic junction obstruction and healthy kidney tissues. Intriguingly, the proteomics revealed extensive metabolic reprogramming in kidneys from individuals with ureteropelvic junction obstruction. Moreover, we uncovered the dysregulation of NAD⁺ metabolism and NAD⁺-related metabolic pathways, including mitochondrial dysfunction, the Krebs cycle, and tryptophan metabolism, which led to decreased NAD⁺ levels in obstructed kidneys. Importantly, the major NADase CD38 was strongly induced in human and experimental obstructive nephropathy. Genetic deletion or pharmacological inhibition of CD38 as well as NAD⁺ supplementation significantly recovered NAD⁺ levels in obstructed kidneys and reduced obstruction-induced renal fibrosis, partially through the mechanisms of blunting the recruitment of immune cells and NF-κB signaling. Thus, our work not only provides an enriched resource for future investigations of obstructive nephropathy but also establishes CD38-mediated NAD⁺ decline as a potential therapeutic target for obstruction-induced renal fibrosis.

CAKUT: A Pediatric and Evolutionary Perspective on the Leading Cause of CKD in Childhood

The global prevalence of chronic kidney disease (CKD) is increasing rapidly, due to increasing environmental stressors through the life cycle. Congenital anomalies of kidney and urinary tract (CAKUT) account for most CKD in children, with a spectrum that can lead to kidney failure from early postnatal to late adult life. A stressed fetal environment can impair nephrogenesis, now recognized as a significant risk factor for the development of adult CKD. Congenital urinary tract obstruction is the leading cause of CKD due to CAKUT and can itself impair nephrogenesis as well as contribute to progressive nephron injury. Early diagnosis by ultrasonography in fetal life by an obstetrician/perinatologist can provide important information for guiding prognosis and future management. This review focuses on the critical role played by the pediatrician in providing timely evaluation and management of the patient from the moment of birth to the transfer to adult care. In addition to genetic factors, vulnerability of the kidney to CKD is a consequence of evolved modulation of nephron number in response to maternal signaling as well as to susceptibility of the nephron to hypoxic and oxidative injury. Future advances in the management of CAKUT will depend on improved biomarkers and imaging techniques.

Febrile urinary tract infection after Double-J stent removal is associated with restenosis after laparoscopic pyeloplasty: A propensity score matched analysis of 503 children

OBJECTIVE

To analyze the association between the febrile urinary tract infection (fUTI) after Double-J (DJ) stents removal and restenosis after laparoscopic pyeloplasty (LP).

STUDY DESIGN

We retrospectively reviewed the clinical data of patients who were treated with transperitoneal LP for ureteropelvic junction obstruction from 2016 to 2020. Patients were divided into two groups according to whether they developed fUTI after DJ stent removal within 48 h. The 1:3 Propensity Score Matched (PSM) method was used to balance confounding variables.

RESULTS

503 patients were included in the study. 28 (5.57%) patients developed fUTI after DJ stent removal. Compared with the non-fUTI group, age was younger, and weight was lower (P < 0.05) in the fUTI group. Restenosis occurred in 11 (2.2%) patients, of which six patients developed fUTI after DJ stent removal. The revision surgery rate in the fUTI group was significantly higher than in the non-fUTI group (21.4% vs. 1.1%, P < 0.01). After PSM, the results remained consistent. For 492 patients without restenosis, 22 patients developed fUTI. Compared with the non-fUTI group, the larger anteroposterior diameter (APD) and higher APD/cortical thickness (P/C) ratio were observed in the fUTI group at three months and six months postoperatively (P < 0.05), but the difference vanished at 12 months and 24 months after surgery (Figure).

DISCUSSION

FUTI after DJ stent removal is not uncommon after LP, and surgeons are often concerned about the possibility of restenosis. In the present study, although our results demonstrated a significant association between them, restenosis patients comprise only about 20% of fUTI patients. Based on our clinical observations, fUTI is often developed in children from 1 to 6 years of age, and the younger patients may be afraid of voiding because of the postoperative pain after DJ stent removal. Besides, intraoperative manipulation of DJ stent removal may lead to transient edema in the anastomotic site, causing the fUTI. For patients who develop fUTI after DJ stent removal but without persistent symptoms, the transient worsening of hydronephrosis during the early postoperative period may not impact long-term outcomes (As shown in Figure). Additional follow-up is needed to prevent the deterioration of renal function.

CONCLUSIONS

Our result demonstrated that fUTI after DJ stent removal is associated with restenosis after LP. For fUTI patients without restenosis, APD and P/C ratio exhibited transient worsening at three months and six months postoperatively, decreasing gradually during follow-up. Patients who develop fUTI after DJ stent removal should be monitored.

Functional recoverability post-pyeloplasty in children with ureteropelvic junction obstruction and poorly functioning kidneys: Systematic review

BACKGROUND

The management of poorly functioning kidneys (PFK) associated with ureteropelvic junction obstruction (UPJO) is controversial. There is contradictory information about how to best manage these cases: pyeloplasty or nephrectomy?

OBJECTIVE

To systematically summarize the available evidence concerning the effects of pyeloplasty on the differential renal function of PFK in children with unilateral UPJO, highlighting the ongoing challenges in their definition, management, and long-term follow-up. In addition, we aim to verify potential predictors of renal functional recoverability that could help clinicians choose candidates for pyeloplasty.

METHODS

We searched several databases including PubMed, Embase, and Cochrane Library CENTRAL until August 20, 2021, according to the PRISMA guidelines. The following concepts were searched: pediatric, ureteropelvic junction obstruction, UPJO, pyeloplasty, recovery, split renal function, and differential renal function. We enrolled studies where the PFK was defined as preoperative differential renal function (DRF) ≤30% by renal scintigraphy. Potential predictors of renal functional recoverability were assessed and compared among studies. The quality of the included studies was evaluated using a modified version of the Newcastle-Ottawa scale (NOS).

RESULTS

1499 citations perceived as relevant to screening were retrieved. After screening, 20 studies were included, comprising a total of 625 cases. The number of patients in each study varied between 5 and 84, while the average post-surgical follow-up duration ranged between 3 months and 180 months. The most significant preoperative predictive factor for postoperative functional recoverability was the baseline DRF, especially when antenatally diagnosed. The quality was considered average in a significant portion of included studies.

CONCLUSION

A significant proportion of PFK showed an increase of DRF post-pyeloplasty. However, no consistent predictive factors for functional recoverability have yet been determined apart from preoperative DRF. Until further evidence appears, pyeloplasty should be considered a valid option in the armamentarium of UPJO management in PFK.

Risk Factors of Urinary Tract Infection in Pediatric Patients with Ureteropelvic Junction Obstruction after Primary Unilateral Pyeloplasty

Objective

Ureteropelvic junction obstruction (UPJO) represents to a leading cause of fetal hydronephrosis, which is associated with urinary tract infection (UTI) and urinary stone disease. This study is aimed at investigating risk factors of UTI in pediatric patients with UPJO after primary unilateral pyeloplasty.

Methods

The records of a consecutive series of patients undergoing primary pyeloplasty at a single institution between June 2015 and November 2021 were retrospectively reviewed. Demographic and clinical characteristics, including age, gender, weight, height, body mass index (BMI), creatinine (Cr), blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), neutrophil ratio, lymphocyte ratio, neutrophil/lymphocyte ratio, renal pelvis anteroposterior diameter (APD), renal cortex thickness, caliectasis, open or laparoscopic pyeloplasty, and internal drainage or external drainage, were collected and analyzed. The incidence of postoperative UTI and its risk factors was analyzed.

Results

A total of 504 patients were enrolled in the study, and they were classified into the UTI group (n = 188) and non-UTI group (n = 361). Univariate analysis of the incidence of UTI revealed that age, gender, weight, height, BMI, surgical modality, Cr level, BUN level, neutrophil ratio, lymphocyte ratio and neutrophil/lymphocyte ratio, renal cortex thickness, and postoperative drainage modality were associated with UTI incidence after pyeloplasty in pediatric patients with UPJO. Multivariate analysis revealed that male gender, <19 months, weight < 11.5 (kg), height < 83 (cm), BMI < 17.09, BUN > 4.08 (mmol/L), and internal drainage were risk factors of postoperative UTI in pediatric patients with UPJO.

Conclusion

Our study demonstrated that male gender, <19 months, weight < 11.5 (kg), height < 83 (cm), BMI < 17.09, BUN > 4.08 (mmol/L), and internal drainage were risk factors of UTI in pediatric patients with UPJO after primary unilateral pyeloplasty, which may provide reference for prophylactic antibiotics for those patients with risk factors.

Prenatal Prediction of Fetal Growth Restriction and Postnatal Outcomes by Ultrasound Assessment of Fetal Myocardial Performance Index and Blood Flow Spectrum

Objective

Fetal growth restriction (FGR) affects 5% to 10% of newborns and is a major determinant of perinatal morbidity and mortality. Myocardial performance index (MPI), also known as the Tei index, is a useful, noninvasive, and Doppler-derived myocardial performance tool for fetal cardiac function evaluation. The purpose of the study is to evaluate ultrasonic prediction on FGR and postnatal outcomes using MPI and blood flow spectrum.

Methods

This retrospective study included 240 pregnant women developing FGR and 240 healthy pregnant women. The blood flow spectrum of middle cerebral artery (MCA), umbilical artery (UA), and ductus venous including systolic to diastolic ratio (S/D), resistant index (RI), pulse index (PI), and peak ventricular systolic velocity/atrial contraction valley velocity (S/a) were examined using the GE Voluson E8 ultrasound system.

Results

The MPI, S/D, RI, PI of UA, and S/a were all higher but S/D, RI, and PI of MCA were lower in the FGR group than those in the control group (P < 0.001). The MPI, S/D, RI, PI of UA, S/D, RI, PI of MCA, and ductus venous S/a yielded AUC of 0.813, 0.835, 0.791, 0.804, 0.789, 0.796, 0.803, and 0.784 when they were used to predict the incidence of FGR. Of note, the pregnant women with poor pregnancy outcomes exhibited higher values of MPI, S/D, RI, PI of UA, and S/a with lower scores of 1 min Apgar concomitant with lower values regarding S/D, RI, and PI of MCA than those with favorable pregnancy outcomes (P < 0.001). The MPI (r = -0.623), S/D (r = -0.660), RI (r = -0.601), PI (r = -630) of UA, and S/a (r = -0.573) shared negative correlations with 1 min Apgar scores (P < 0.001). Of note, the S/D (r = 0.562), RI (r = 0.597), and PI (r = 0.619) of MCA were positively correlated with 1 min Apgar scores (P < 0.001). It was revealed that the MPI, S/D, RI, PI of UA, S/D, RI, PI of MCA, and ductus venous S/a yielded AUC of 0.806, 0.833, 0.774, 0.788, 0.807, 0.729, 0.748, and 0.770 when they were used to predict the incidence of poor pregnancy outcomes for pregnant women developing FGR.

Conclusion

Our study demonstrates good ultrasonic prediction on FGR and postnatal outcomes using MPI and blood flow spectrum.

Redo laparoscopic pyeloplasty for recurrent ureteropelvic junction obstruction: Propensity score matched analyses of a high-volume center

PURPOSE

Review the experience of redo laparoscopic pyeloplasty (RLP) in patients with recurrent ureteropelvic junction obstruction (UPJO) in comparison to primary laparoscopic pyeloplasty (PLP) and redo open pyeloplasty (ROP), and determine the feasibility and effectiveness of RLP for recurrent UPJO in children.

METHODS

We retrospectively reviewed the clinical data of patients treated with transperitoneal PLP, RLP, and ROP for UPJO from December 2015 to December 2022. The Propensity score matching (PSM) was used to balance confounding variables. RLP patients were 1:4 matched with PLP and 1:3 matched with ROP. The primary outcomes were failure and post-operative complications. Complications were classified according to the Clavien-Dindo grading system.

RESULTS

The study included ten patients who underwent RLP, 43 patients who underwent ROP, and 412 patients who underwent PLP. The follow-up time ranged from 6 to 36 months in the RLP group, 12 to 60 months in the PLP group, and 24 to 54 months in the ROP group. In the RLP group, no failure but three post-operative complications (Clavien grade II) were observed during the follow-up. Compared with the PLP group, the older age, higher weight, larger pre-operative anteroposterior diameter (APD) and APD/cortical thickness (P/C ratio), longer operation time, and post-operative length of stay (LOS) in the RLP group (P < 0.05). After PSM, longer operation time and post-operative LOS were observed in the RLP group (P < 0.05). Compared with the ROP group, the older age, higher weight, and longer post-operative LOS in the RLP group (P < 0.05). After PSM, longer post-operative LOS was observed in the ROP group (P < 0.05). The failure and complication rates were comparable between RLP and PLP or RLP and ROP (P > 0.05).

CONCLUSIONS

Our result demonstrated that RLP performed as well as PLP except for a longer operation time. Compared with ROP, RLP has the advantages of a clearer surgical view, sufficient exposure, clearer anatomical landmark position, and minor trauma with a comparable clinical outcome. On experienced hands, RLP for recurrent UPJO after is a safe and effective procedure and should be considered an excellent alternative to the more commonly recommended ROP in select patients.

Hsa_circRNA_0045861 promotes renal injury in ureteropelvic junction obstruction via the microRNA-181d-5p/sirtuin 1 signaling axis

Background

Ureteropelvic junction obstruction (UPJO) is one of the most common causes of hydronephrosis in children. This study explored the effects and the regulatory mechanisms of the circular RNA (circRNA) hsa_circRNA_0045861 (circRNA_0045861) in UPJO.

Methods

RNA sequencing was used to identify the differentially expressed circRNAs in UPJO. The effects of circRNA_0045861 on renal cell apoptosis was investigated by flow cytometry and Western blot analysis. Furthermore, we used bioinformatics methods to predict the possible target genes of circRNA_0045861. Fluorescence in-situ hybridization and dual-luciferase reporter assays were performed to validate the target genes of circRNA_0045861. Finally, we evaluated the effects of circRNA_0045861 target gene miR-181d-5p on UPJO-induced renal fibrosis in vivo.

Results

RNA sequencing identified 63 upregulated and 64 downregulated circRNAs in UPJO patients. The expression of circRNA_0045861 was significantly elevated in kidney damage both in vivo and in vitro. Silencing circ_0045861 inhibited transforming growth factor (TGF)-β1-induced apoptosis in vitro in human kidney 2 (HK-2) cells. Furthermore, circ_0045861 was shown to directly interact with the microRNA miR-181d-5p and regulate the expression of sirtuin 1 (SIRT1), thereby promoting the progression of apoptosis and renal injury. In addition, overexpression of miR-181d-5p inhibited cell apoptosis and renal fibrosis in a mouse model through downregulating the SIRT1/p53 pathway.

Conclusions

Circ_0045861 may be a novel candidate circRNA in the pathogenesis of UPJO by acting as a pro-apoptotic factor via the miR-181d-5p/SIRT1 axis.