The causes and consequences of paediatric kidney disease on adult nephrology care

Kidney Transplantation in Congenital Abnormalities of Kidney and Urinary Tract (CAKUT)

Congenital anomalies of the kidney and urinary tract (CAKUT) are a common cause of chronic kidney disease in children. Most patients will reach end-stage renal function and dialysis or transplantation in childhood or early adulthood. Patients with CAKUT deserve a careful evaluation before a kidney transplant; detailed imaging and functional studies are necessary, particularly in the presence of lower urinary tract abnormalities, and surgical procedures are advisable in selected cases. A higher incidence of complications has been reported after a kidney transplant in CAKUT, mainly urinary tract infections. However, in the long term, the prognosis seems to be comparable to other kidney diseases. A large number of reports are available in the literature on medical and surgical management of patients with CAKUT before, during, and after a kidney transplant; almost all recommendations of surgical procedures before a kidney transplantation are based on retrospective not controlled studies or personal opinions; prospective controlled studies are needed. In this narrative, nonsystematic review, we report the results of recently published selected studies and underline questions that should be addressed in future guidelines.

Swiss Consensus on Prenatal and Early Postnatal Urinary Tract Dilation: Practical Approach and When to Refer

Urinary tract dilations (UTDs) are the most frequent prenatal renal anomaly. The spectrum of etiologies causing UTD ranges from mild spontaneously resolving obstruction to severe upper and lower urinary tract obstruction or reflux. The early recognition and management of these anomalies allows for improved renal endowment prenatally and ultimately better outcome for the child. The role of the general obstetrician and pediatrician is to recognize potential prenatal and postnatal cases addressed to their practice and to refer patients to specialized pediatric nephrology and urology centers with a sense of the urgency of such a referral. The aim of this paper is to offer clinical recommendations to clinicians regarding the management of neonates and children born with prenatally detected UTD, based on a consensus between Swiss pediatric nephrology centers. The aim is to give suggestions and recommendations based on the currently available literature regarding classifications and definitions of prenatal and postnatal UTD, etiologies, prenatal and postnatal renal function evaluation, investigations, antibiotic prophylaxis, and the need for referral to a pediatric nephrologist and/or urologist. The overarching goal of a systematic approach to UTD is to ultimately optimize kidney health during childhood and improve long-term renal function prognosis.

Human HPSE2 gene transfer ameliorates bladder pathophysiology in a mutant mouse model of urofacial syndrome

Rare early-onset lower urinary tract disorders include defects of functional maturation of the bladder. Current treatments do not target the primary pathobiology of these diseases. Some have a monogenic basis, such as urofacial, or Ochoa, syndrome (UFS). Here, the bladder does not empty fully because of incomplete relaxation of its outflow tract, and subsequent urosepsis can cause kidney failure. UFS is associated with biallelic variants of HPSE2, encoding heparanase-2. This protein is detected in pelvic ganglia, autonomic relay stations that innervate the bladder and control voiding. Bladder outflow tracts of Hpse2 mutant mice display impaired neurogenic relaxation. We hypothesized that HPSE2 gene transfer soon after birth would ameliorate this defect and explored an adeno-associated viral (AAV) vector-based approach. AAV9/HPSE2, carrying human HPSE2 driven by CAG, was administered intravenously into neonatal mice. In the third postnatal week, transgene transduction and expression were sought, and ex vivo myography was undertaken to measure bladder function. In mice administered AAV9/HPSE2, the viral genome was detected in pelvic ganglia. Human HPSE2 was expressed and heparanase-2 became detectable in pelvic ganglia of treated mutant mice. On autopsy, wild-type mice had empty bladders, whereas bladders were uniformly distended in mutant mice, a defect ameliorated by AAV9/HPSE2 treatment. Therapeutically, AAV9/HPSE2 significantly ameliorated impaired neurogenic relaxation of Hpse2 mutant bladder outflow tracts. Impaired neurogenic contractility of mutant detrusor smooth muscle was also significantly improved. These results constitute first steps towards curing UFS, a clinically devastating genetic disease featuring a bladder autonomic neuropathy.

Therapeutic Management of Children with Vesicoureteral Reflux

Contrasting data refer to therapies for vesicoureteral reflux (VUR), such as surgical treatments and continuous antibiotic prophylaxis (CAP). This study evaluated the effectiveness of these approaches in children with VUR, analyzing the recurrence of febrile urinary tract infections (UTIs) and the resolution of VUR after the treatment. A total of 350 pediatric patients underwent contrast-enhanced voiding urosonography (ceVUS) to diagnose a VUR, whereas renal scintigraphy evaluated potential scars. After 12 months from the treatment, the VUR, the relapse of febrile UTIs, and reflux-related nephropathy were analyzed. Twenty-seven children had recurrent febrile UTIs after surgical therapy, with a greater rate of relapses observed in III and V VUR grades. Thirteen patients who underwent surgery had scars, independently of VUR grades and gender, with evidence of chronic renal failure at the end of the follow-up period. A total of 140 subjects were treated with CAP, and 30% of them continued to suffer from febrile UTIs. Ninety-five patients with VUR underwent ceVUS after 12 months, with persistent reflux in fifty-two patients. All of them had severe VUR, correlating with the age at diagnosis and gender. CAP therapy prevented scarring better than surgery, especially in children with III and V grades of VUR. A late onset of VUR or VUR involving neonatal patients is rarely a reversible process. This study identified predictors of success or failure of surgical or CAP therapies, evaluating the relapse of UTIs or persistent reflux after the treatment and giving prognostic information in children with VUR.

Conflicting views of physicians and surgeons concerning pediatric urinary tract infection: a comparative review

BACKGROUND

A first febrile urinary tract infection (UTI) is a common condition in children, and pathways of management have evolved over time.

OBJECTIVE

To determine the extent to which pediatricians and surgeons differ in their investigation and management of a first febrile UTI, and to evaluate the justifications for any divergence of approach.

MATERIALS AND METHODS

A literature search was conducted for papers addressing investigation and/or management following a first febrile UTI in children published between 2011 and 2021. Searches were conducted on Medline, Embase, and the Cochrane Controlled Trials Register. To be eligible for inclusion, a paper was required to provide recommendations on one or more of the following: ultrasound (US) and voiding cystourethrogram (VCUG), the need for continuous antibiotic prophylaxis and surgery when vesicoureteral reflux (VUR) was detected. The authorship required at least one pediatrician or surgeon. Authorship was categorized as medical, surgical, or combined.

RESULTS

Pediatricians advocated less imaging and intervention and were more inclined to adopt a "watchful-waiting" approach, confident that any significant abnormality, grades IV-V VUR in particular, should be detected following a second febrile UTI. In contrast, surgeons were more likely to recommend imaging to detect VUR (p<0.00001), and antibiotic prophylaxis (p<0.001) and/or surgical correction (p=0.004) if it was detected, concerned that any delay in diagnosis and treatment could place the child at risk of kidney damage. Papers with combined authorship displayed intermediate results.

CONCLUSION

There are two distinct directions in the literature regarding the investigation of an uncomplicated first febrile UTI in a child. In general, when presented with a first febrile UTI in a child, physicians recommend fewer investigations and less treatment, in contrast to surgeons who advocate extensive investigation and aggressive intervention in the event that imaging detects an abnormality. This has the potential to confuse the carers of affected children.

Congenital Anomalies of the Kidney and Urinary Tract: A Continuum of Care

Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of kidney failure in children and adolescents. CAKUT describes a wide spectrum of structural disorders with a prenatal origin. The etiology of CAKUT is multifactorial, including environmental, nongenetic, and genetic causes that impact kidney development as well as upper and lower urinary tract development. Adult nephrologists who treat patients with CAKUT may be challenged by the underlying diseases they are not familiar with and the accumulation of chronic kidney disease complications in childhood. This article discusses CAKUT etiology and presentation, the course during childhood and adolescence, as well as adult issues in CAKUT patients including CKD complications, urologic interventions, and genetic counseling. A smooth transition of CAKUT patients from pediatric to adult care can be challenging. Semin Nephrol 43:x-xx © 2023 Elsevier Inc. All rights reserved.

A systematic review of kidney-on-a-chip-based models to study human renal (patho-)physiology

As kidney diseases affect ∼10% of the world population, understanding the underlying mechanisms and developing therapeutic interventions are of high importance. Although animal models have enhanced knowledge of disease mechanisms, human (patho-)physiology may not be adequately represented in animals. Developments in microfluidics and renal cell biology have enabled the development of dynamic models to study renal (patho-)physiology in vitro. Allowing inclusion of human cells and combining different organ models, such as kidney-on-a-chip (KoC) models, enable the refinement and reduction of animal experiments. We systematically reviewed the methodological quality, applicability and effectiveness of kidney-based (multi-)organ-on-a-chip models, and describe the state-of-the-art, strengths and limitations, and opportunities regarding basic research and implementation of these models. We conclude that KoC models have evolved to complex models capable of mimicking systemic (patho-)physiological processes. Commercial chips and human induced pluripotent stem cells and organoids are important for KoC models to study disease mechanisms and assess drug effects, even in a personalized manner. This contributes to the Reduction, Refinement and Replacement of animal models for kidney research. A lack of reporting of intra- and inter-laboratory reproducibility and translational capacity currently hampers implementation of these models.

Robotic ureteral reimplantation and uretero-ureterostomy treating the ureterovesical junction pathologies in children: technical considerations and preliminary results

Robot-assisted laparoscopic extravesical ureteral reimplantation (RALUR) and robotic ureteroureterostomy (RUU) are two mini-invasive surgical techniques that have begun to be performed in pediatric urology in recent years. RALUR has been employed especially for VUR treatment, while RUU is considered principally in case of complex doubled ureteral systems. Our aim is to discuss the safety and feasibility of these approaches in children, focusing on technical considerations and supporting their use in different anomalies and pathologies of the ureterovesical junction. We retrospectively collected data about 58 patients who underwent 44 dismembered RALUR (D-RALUR), 28 non-dismembered RALUR (ND-RALUR) and 5 RUU between May 2020 and December 2021. Indications for surgery were primary or secondary vesicoureteral reflux, megaureter, secondary UVJ obstructions, complicated doubled ureteral systems. Mean age was 3.5 years (range 0.6-12.9) and mean weight 17.1 (range 7.2-80). No intraoperative complications occurred nor conversion to open approach were reported. Major postoperative complications were reported in 11.7% of cases with a higher incidence for ND-RALUR. Mean hospital stay was 2.14 days (range 1-8). Success rate at the short-term follow-up was 91.9% for D-RALUR, 96.3% for ND-RALUR and 100% for RUU. RALUR and RUU are two feasible and safe procedures to perform in children. RALUR represents the most required and adequate technique in the treatment of UVJ pathologies, however, in selected cases RUU could represent an effective alternative that has to be considered.