Ontogeny of bladder agenesis in rats induced by adriamycin

Bladder Agenesis: A Systematic Review

Bladder agenesis is a rare congenital deformity characterized by the absence of the bladder. It is primarily observed in postmortem dissections of stillbirths rather than live births. The condition is often associated with other congenital anomalies, leading to the hypothesis that most affected fetuses do not survive to term. However, the exact cause and specific associated anomalies remain unclear and poorly described in the literature. The limited mention of bladder agenesis in textbooks and literature underscores the importance of creating a comprehensive source for future research in this field. Therefore, our objective is to collect and analyze data on bladder agenesis, focusing on associated anomalies and potential causes, to enhance our understanding of the condition. We conducted a thorough review of reports collected from three databases, Google Scholar, PubMed, and Science Direct, last searched on July 30, 2023, starting with 327 reports. Excluding duplicates and records written in languages other than English, veterinary studies, irrelevant reports, or stillbirths. Inclusion criteria were the following: cases must have proven bladder agenesis, not hypoplasia, and must have most of the information, including the age of diagnosis, presenting symptoms, gender, associated anomalies, and management or outcome of the patient. A quality assessment was conducted according to the Joanna Briggs Institute checklist for case reports. A total of 65 case reports from 56 articles were included in the review. Through our manual analysis, we documented a wild array of malformations associated with bladder agenesis. Among the reports reviewed, 93% exhibited urinary system malformations beside bladder agenesis, 77% were found to have reproductive malformations, 44% had gastrointestinal anomalies, 38% showed musculoskeletal malformations, 28% had cardiac malformations, and another 28% had vascular anomalies. The overall mortality rate was 38%, with a higher rate of 74% for males compared to 20% for females. By collating and analyzing those case reports, we aim to contribute to a better understanding of bladder agenesis and its associated anomalies, facilitating further investigations and advancements in the field.

Antenatal biological models in the characterization and research of congenital lower urinary tract disorders

Congenital lower urinary tract disorders are a family of diseases affecting both urinary storage and voiding as well as upstream kidney function. Current treatments include surgical reconstruction but many children still fail to achieve urethral continence or progress to chronic kidney disease. New therapies can only be achieved through undertaking research studies to enhance our understanding of congenital lower urinary tract disorders. Animal models form a critical component of this research, a corner of the triangle composed of human in-vitro studies and clinical research. We describe the current animal models for two rare congenital bladder disorders, posterior urethral valves (PUV) and bladder exstrophy (BE). We highlight important areas for researchers to consider when deciding which animal model to use to address particular research questions and outline the strengths and weaknesses of current models available for PUV and BE. Finally, we present ideas for refining animal models for PUV and BE in the future to stimulate future researchers and help them formulate their thinking when working in this field.

Adriamycin-Induced Models of VACTERL Association

Animal models are of great importance for medical research. They have enabled analysis of the aetiology and pathogenesis of complex congenital malformations and have also led to major advances in the surgical and therapeutic management of these conditions. Animal models allow us to comprehend the morphological and molecular basis of disease and consequently to discover novel approaches for both surgical and medical therapy. The anthracycline antibiotic adriamycin was incidentally found to have teratogenic effects on rats, producing a range of defects remarkably similar to the VACTERL association of congenital anomalies in humans, providing a reproducible animal model of this condition. VACTERL association is a spectrum of birth defects which includes vertebral, anal, cardiovascular, tracheo-oesophageal, renal and limb anomalies. In recent years, adriamycin rodent models of VACTERL have provided valuable insights into the pathogenesis of this complex association, particularly in relation to tracheo-oesophageal malformations. The adriamycin rat model and adriamycin mouse model are now well established in the investigation of the morphology of faulty organogenesis and the regulation of gene expression in tracheo-oesophageal anomalies.

Bladder agenesis and bilateral ectopic ureters draining into the vagina in a female infant: demonstrated by MR imaging

Complete agenesis of the bladder and urethra is an extremely rare congenital anomaly and most of these patients are stillborn or die during infancy. We report the case of a 1-month-old female infant with bladder and urethral agenesis who presented with bilateral dilated and tortuous ectopic ureters draining into the vagina diagnosed using MR imaging. Our patient was maintained on antibiotic prophylaxis and she remained well during the 3-year follow-up. MR imaging can be used as a valuable modality for genitourinary abnormalities, particularly in cases of inconclusive ultrasound or retrograde pyelography findings.

Urinary bladder agenesis in an alpaca (Vicugna pacos) cria

A 10-day-old female alpaca (Vicugna pacos) cria with a history of urinary straining and dribbling was presented for evaluation. The animal had markedly elevated blood fibrinogen (800 mg/dl), mildly elevated phosphorus (9.3 mg/dl), and minimally elevated blood urea nitrogen (38 mg/dl) concentrations. The total protein (5.0 g/dl) concentration was mildly decreased. These findings were suggestive of mild renal disease. An abdominal ultrasound revealed bilateral hydronephrosis and hydroureter, and no urinary bladder was identified. Gross postmortem examination revealed urinary bladder agenesis and bilateral hydronephrosis and hydroureter, with both ureters opening into a sinus in the caudal vagina. Histologic examination of the kidneys showed necrosuppurative pyelonephritis with pelvic dilation, and both ureters had mild lymphoplasmacytic and histiocytic inflammation.

Investigation of histopathologic changes in the ureter walls in vesicoureteral reflux

PURPOSE

This study aimed to determine the histopathologic changes in ureteral walls (UWs) in children with vesicoureteral reflux (VUR).

METHODS

Twenty ureteral specimens taken from children were divided into 2 groups, refluxing (R) and control (C) groups, each containing 10 specimens. Wall thickness of the ureter, tunica muscularis of the ureter, mucosal thickness of the ureter (uroepithelium), collagen thickness of the ureter, mucosal change, and inflammation were evaluated in resected distal UWs in children with VUR.

RESULTS

The mean wall thickness of the ureter, mean tunica muscularis of the ureter, and mean uroepithelium values of the UWs in the R group were not significantly lower compared to those in the C group. Collagen thickness values in the R group were significantly lower than those in the C group.

CONCLUSIONS

Our data suggest that wall thickness (tunica muscularis and uroepithelium) was not significantly decreased, but collagen thickness of the ureter was decreased in the UWs of children with VUR.

Investigation of histopathologic changes in the ureter walls in experimental congenital obstructive uropathy

BACKGROUND/PURPOSE

The aim of this study is to determine the histopathologic changes in the ureter wall in experimental urinary bladder hypoplasia and agenesis.

METHODS

Timed pregnant rats were randomly divided and received intraperitoneal Adriamycin (ADR) at 2 mg/kg on gestational days (GD) 6 to 9 (ADR group) and saline at 2 mL/kg on GD 6 to 9 (SF group). The control (C) group did not receive any medication in their pregnancy. Fetuses were harvested near term on GD 21 and dissected under a dissecting microscope and examined for urinary system abnormalities.

RESULTS

Diameter of ureter lumen was significantly increased, but wall thickness, tunica muscularis, and epithelial thickness of the ureter were decreased in the ADR group as compared with the C and SF groups.

CONCLUSIONS

Diameter of the ureter lumen was increased, but wall thickness, tunica muscularis, and uroepithelium of the ureter were decreased in the ADR group in the intrauterine period. The diameter of the ureter lumen and wall thickness of ureter (tunica muscularis of ureter and uroepithelium) were increased following obstructive uropathy after the birth.

The Adriamycin rat/mouse model and its importance to the paediatric surgeon

The teratogenic effect of Adriamycin (doxorubicin) in the rat model, and more recently in the mouse, has provided paediatric surgeons with a reliable, easily reproducible method of studying the embryology and molecular biology for a range of complex congenital anomalies. Concomitantly these animal models have stimulated interest among embryologists for the effect on the notochord, shedding more light on the important organizational role of this structure in the developing embryo. Finally, as more is learnt of the pathogenesis of the various malformations induced by Adriamycin, future therapeutic interventions involving gene therapy, drugs or surgery may arise. This article reviews the establishment of the Adriamycin rat and mouse models, examines their impact on various congenital malformations, and suggests targets for further research.

Bilateral megaureters in the Adriamycin rat model

Congenital obstructive uropathy is associated with significant morbidity and mortality in the human neonate. The pathophysiology of congenital obstructive uropathy is poorly understood. There are very few experimental models of prenatal obstruction of the urinary tract, except in the fetal lamb or inbred rats. Prenatal exposure to Adriamycin in a rat model leads to a spectrum of malformations including urinary tract anomalies. We hypothesized that Adriamycin administration during a particular time frame could yield a high incidence of urinary tract anomalies and therefore designed this study to investigate the rates of urinary tract anomalies at different windows of Adriamycin injection in rat embryos. Adriamycin (1.75 mg/kg) was administered intraperitoneally to pregnant rats at different times from days 6 to 10 of gestation. Control animals were given saline. Embryos recovered on gestational day 21 by cesarean section were examined for urinary tract anomalies, and malformations were noted. Sections were then processed for paraffin embedding, sectioned at 5 mum, and stained with hematoxylin and eosin for histological examination. Anomalies of the urinary tract occurred maximally following Adriamycin administration on days 7, 8, and 9 of gestation (91.6%) compared with 16% of controls. The most common urinary tract anomaly in the Adriamycin group was bilateral megaureters with a hypoplastic bladder (81%). Other anomalies included unilateral or bilateral ureterohydronephrosis with a normal-sized bladder, duplex kidney, and unilateral or bilateral renal agenesis. In conclusion, the critical embryologic window for the development of bilateral megaureters with a small bladder in the Adriamycin rat model occurs following Adriamycin administration on gestational days 7-9. This simple experimental model of bilateral megaureter may allow further research into the pathophysiology of this condition.