Refluxing Kidneys Research Articles

Acute pyelonephritis in adults. Should we adopt the pediatric guidelines?

Purpose: There are no guidelines, what recommend pro or against cystography for identification of VUR for adults who suffer from first episode of pyelonephritis. The aim of this study was to look at incidence of VUR in adults with first episode of pyelonephritis, and to highlight recommendations for possible reflux investigation in these patients. Methods: We have performed retrospective review of all patients who admitted at our department over the last decade with the working diagnosis of acute pyelonephritis. Following discharge from the department, individuals with no pre-existing urological history were advised to undergo a VCUG or CEVUS. Results: We have identified 76 patients (62 females and 14 males) with an average age of 31.73 years who were hospitalized in our departments between 2006 and 2022. Forty-eight (63%) presented with right pyelonephritis, 26(34%) with left, and 2(3%) had bilateral disease. Of those, 23(30%) patients returned for clinical follow-up after completion of VCUG/CEVUS. Reflux was demonstrated in 14(60%) patients comprising 18 renal refluxing units (RRU). Six had grade IV reflux, 4 grade III, 4 grade II, and 4 grade I respectively. DMSA demonstrated 27.2 ± 11.9% relative function of the reflux kidney. Of those VUR patients, 9(64%) underwent endoscopic correction, 1(7%) refused surgery, and 4(29%) are under clinical follow-up. Conclusions: Our data demonstrate high incidence of VUR in adult patients with acute pyelonephritis patients, therefore VUR investigation at least should be considered in adult patients even after first episode of pyelonephritis, especially in cases where there is evidence of nephronia, abscess, kidney scars, atrophic kidney, or hydronephrosis.

A Retrospective View of Post Renal Transplant Urinary Tract Infections: An Experience of A UK Transplant Centre

Urinary tract infections (UTIs) are prevalent post renal transplant complication. These infections are most common in renal transplant recipient’s contrary to their incidence in general healthy population as shown by previous studies. Though the frequencies of occurrences are different in renal transplant patients. There is general lack of consensus on the risk factors associated with development of UTIs in renal transplant patients as well as effects posed by them and occurrence of mortality in patient group. This retrospective cohort study investigated and included adults’ patients who were operated for renal transplant in a single transplant center in UK from Jan 2014 to December 2023. The number of patients were 604 with two hundred and fifty-nine developed one or more UTIs in 42 months follow-up period. Significant risk factors for post-transplant UTIs were advanced age, female gender, reflux kidney disease, use of azathioprine and cadaveric donor. UTIs did not increase risk for renal graft loss, but were associated with increased mortality (3.5 odds ratio, 95% confidence interval 1.68–7.23). We conclude UTIs may be associated with an increased mortality risk in renal transplant recipients. Prevention of UTIs in high-risk renal transplant patients or those with recurrent UTIs may possibly decrease post-transplant mortality.

Heavy Scarring in the Unilateral Refluxing Kidney May Sign of Contralateral Reflux After Reimplantation

Heavy Scarring in the Unilateral Refluxing Kidney May Sign of Contralateral Reflux After Reimplantation

HucMSC exosomes attenuate partial bladder outlet obstruction-induced renal injury and cell proliferation via the Wnt/β-catenin pathway

Bladder outlet obstruction (BOO) can cause serious complications including kidney damage; nevertheless, there are currently no animal models for studying BOO-induced kidney damage. Mesenchymal stem cells (MSCs) are widely used in therapeutic studies of renal fibrosis. However, MSC-derived exosomes show improved safety profile and more controllable characteristics compared with those of MSCs. Herein, we established a kidney injury mouse model of partial bladder outlet obstruction (PBOO) and evaluated the effects of human umbilical cord MSC-derived exosomes (hucMSC-Exos) on PBOO-induced reflux kidney injury in this model. Exosomes were isolated from a hucMSC-conditioned medium, purified by ultracentrifugation, and examined. Living image was performed to indicate the distribution of hucMSC-Exos. The PBOO-treated mice interacted with PBS (phosphate-buffered saline) or hucMSC-Exos. Morphologic changes and expression of interstitial-fibrosis—related, cell proliferation and Wnt/β-catenin signaling-pathway indices were evaluated. At 7 days after induction of PBOO, structural destruction of renal tubules was observed. Expression of the interstitial markers and the cellular-proliferation index increased significantly in the PBOO group compared with the control group. The isolated exosomes were 30–150 nm in diameter, showing a round shape and bilayer membrane structure with CD63, TSG101, Alix expressed, enriched in the kidney of the PBOO group. Administering hucMSC-Exos to post-PBOO mice reversed renal injury and suppressed expression of Wnt/β-catenin signaling pathway-related proteins. hucMSC-Exos inhibited PBOO-induced kidney injury and cellular proliferation and suppressed the Wnt/β-catenin signaling pathway. Our findings will spur the development of novel hucMSC-Exo-mediated therapies for treating patients with renal fibrosis.

Is technetium-99m dimercaptosuccinic acid renal scintigraphy available for predicting vesicoureteral reflux in children with first febrile urinary tract infection under the age of 24 months?

Vesicoureteral reflux (VUR) is a common complication after urinary tract infection (UTI) and can lead to irreversible renal scar. Voiding cystourethrogram is the most reliable technology to detect VUR and its severity, but it is restricted in children's examinations for various shortcomings. This study aimed to evaluate and compare the efficiency of Tc-99m DMSA renal scintigraphy and conventional ultrasonography (USG) in predicting VUR with the gold standard of cystourethrogram results. This retrospective study consisted of 285 first febrile UTI children under the age of 24 months who completed inflammatory indicator examinations, USG, Tc-99m DMSA renal scintigraphy and underwent cystourethrography after controlling infection with prophylactic antibiotics. The efficiency of Tc-99m DMSA renal scintigraphy and USG in predicting VUR was calculated and compared. Abnormal USG (40.23% vs. 21.72%, P = 0.001) and Tc-99m DMSA renal scintigraphy results (87.36% vs. 71.72%, P = 0.004) were more common in VUR children. The sensitivity of USG in predicting VUR was only 40.23%, whereas the sensitivity and negative predictive value of Tc-99m DMSA renal scintigraphy reached 87.63 and 83.58%, respectively. Tc-99m DMSA renal scintigraphy had a higher efficacy than USG in predicting high-grade reflux kidneys (73.87% vs. 33.33%; P < 0.001), but there was no significant difference in predicting low-grade reflux kidneys ( P = 0.703). Tc-99m DMSA renal scintigraphy had a significant higher efficiency in predicting VUR (a common cause of renal scarring, detected on DMSA) in first febrile urinary tract infection children under the age of 24 months as compared with USG, especially in high-grade reflux.

Assessment of distal ureteral and ureterovesical junction visualization on contrast-enhanced voiding urosonography.

Contrast-enhanced voiding urosonography (CEVUS) uses intravesically administered microbubble contrast to detect vesicoureteral reflux (VUR) and urethral anomalies with ultrasound. Multiple studies have suggested CEVUS can replace voiding cystourethrogram (VCUG) as a radiation-free alternative. Analysis of the ureterovesical junction and ureters on VCUG documenting the ureterovesical junction position, ureteral duplication, periureteral diverticula and ureteroceles is important as anatomical variations may affect management and surgical approach. Our purpose was to assess distal ureteral and ureterovesical junction region visualization in children with VUR detected on CEVUS. CEVUS studies performed between June 2018 and March 2019 with reported VUR were retrospectively reviewed by two pediatric radiologists to confirm VUR and to qualitatively assess the ureterovesical junction region for each renal moiety using a 3-point scale for clear, limited or absent visualization of the distal ureter, ureterovesical junction, ureteral duplication, periureteral diverticula and ureteroceles. Thirty-four studies with VUR on CEVUS were identified. Sixty-seven renal moieties were evaluated including a solitary kidney in one child. VUR was detected in 52 moieties by reader 1 and in 53 by reader 2. A single moiety with discrepancy between readers regarding VUR was excluded from statistical analysis. No diverticula were detected by either reader and one ureterocele was detected by both readers. Visualization of the ureterovesical junction was described as clear in 5/52, limited in 14/52 and absent in 33/52 refluxing renal moieties by reader 1 and as clear in 12/52, limited in 20/52 and absent in 20/52 by reader 2. The ureterovesical junction was clearly visualized in 5/52 (9.6%) by reader 1 and 12/52 (23.1%) by reader 2. The Kappa value of -0.29 (confidence interval [CI] -0.25, 0.21) reveals a lack of agreement between the readers for clear versus limited or absent ureterovesical junction visualization. Distal ureteral visualization was described as clear in 14/52, limited in 16/52 and absent in 22/52 refluxing renal moieties by reader 1 and as clear in 27/52, limited in 7/52 and absent in 18/52 by reader 2. The distal ureter was clearly visualized in 14/52 (26.9%) by reader 1 and 27/52 (51.9%) by reader 2. The Kappa of 0.43 (CI 0.22, 0.64) reveals moderate agreement between the readers for clear versus limited or absent distal ureteral visualization. Duplication of the renal collecting system was identified in 13/52 refluxing kidneys by reader 1 and 11/52 refluxing kidneys by reader 2. Visualization of ureteral duplication was described as clear in 9, limited in 4 and absent in 39 of 52 refluxing renal moieties by reader 1 and as clear in 9, limited in 2 and absent in 41 by reader 2. Ureteral duplication was clearly visualized in 9/52 (17.3%) by reader 1 and 9/52 (17.3%) by reader 2. Kappa of 0.87 (CI 0.68, 1) reveals high agreement between the readers for clear versus limited or absent identification of ureteral duplication. The distal ureter and ureterovesical junction region frequently are not clearly visualized in refluxing renal moieties on CEVUS. Awareness of this limitation is important as there may be implications when evaluating patients for surgical management of VUR.

Clinical profile and predisposing factors for the development of urinary tract infection during the first 3 months postrenal transplantation: A tertiary care hospital experience

Background: Infections in renal allograft recipients, especially urinary tract infections (UTI), are an essential factor leading to an increase in morbidity, graft failure, and degrading the health-related quality of life. Aims and Objectives: Our objective is to assess the causes, risk factors, microbiological profile, and antibiotic sensitivity pattern of UTI in renal transplant recipients. Material and Methods: It was a prospective observational study, conducted at the Department of Nephrology, Sir Gangaram Hospital, New Delhi, India. Three hundred ten renal transplant recipients were enrolled. Results: Out of 300 transplant recipients, 107 (35.6%) had UTI. The mean age of patients with UTI was 32 ± 10.5 years. Females have a higher incidence of UTI than males. 64.5% of all diabetic patients had UTI. Escherichia coli (41%) was the most common causative agent. Gram-negative bacilli attributed the majority (88.5%) of cases. Klebsiella pneumonia was found to be multidrug-resistant in most cases. 61% of patients with reflux kidney disease before transplant suffered from UTI. Conclusion: On multivariate analysis in our study, diabetes (P=0.01), prolonged urethral catheterization (p=0.002), and double J stent kept in situ (p=0.03) and reflux kidney disease before transplant (p

Heavy Scarring in the Unilateral Refluxing Kidney May Be Sign of Contralateral Reflux After Reimplantation

Purpose We investigated the role of ipsilateral heavy scarring in the unilateral refluxing kidney for the occurrence of contralateral reflux after reimplantation. The question is: if heavy scarring is a sign of severe dysplasia, can occurence of contralateral reflux be effected by this unilateral sever dysplasia? Material and Methods Forty-five patients (23 male 22 female, mean age 5.3+/- 3.3) who had undergone unilateral reimplantation were included into the study. Presence of multiple scars in renal scan and differential function being less than 30% with diffuse parenchymal damage were accepted as heavy scarring. 19 patients had grade 3, 17 had grade 4, and 9 had grade 5 VUR. Results There were 2 patients with persistent ipsilateral reflux. Contralateral reflux developed in 7 patients (grade 1 in one patient, grade 2 in two patients,grade 3 in four,and grade 5 in one). Bilateral reflux developed only in the patient with ectopic ureter, and recurring reflux was not seen in other anatomic disorder. No relation was found between the preoperative grade, type of reimplantation and reflux to the contralateral kidney. Development of contralateral reflux in patients with heavy ipsilateral scarring was significantly higher (table)(p=0.05). Contralateral reflux was found in 3 patients out of five with heavy scarring and younger than 5 years of age. Reflux recovered within 24.6+/-12.2 (7-41) months in the average. IPSILATERAL SCAR No/minimal scarring Heavy scarring TOTAL NO CONTRALATERAL REFLUX 31 7 38 CONTRALATERAL REFLUX + 3 4 7 TOTAL 34 11 45 Table. The effect of presence of ipsilateral heavy scarring on occurrence of contralateral reflux (p=0.05) Conclusions We found that presence of heavy scarring in ipsilateral kidney may have a role for the prediction of contralateral reflux developing after the unilateral ureteroneocystostomy escpecially in young children. It can be related with primary trigonal disease or pop-off mechanism.

Urodynamic and Histological Changes in a Sterile Rabbit Vesicoureteral Reflux Model

This study aimed to investigate pressure changes of renal pelvis and histological change of kidneys in a surgically induced sterile rabbit vesicoureteral reflux (VUR) model. Five rabbits served as a control group, 7 as the sham-operated group, and 8 served as the VUR group. Three weeks later, urodynamic studies were performed, and histological examinations evaluated degree of inflammation, fibrosis, and tubular damage in the kidneys. At a low infusion rate, renal pelvic pressure in the VUR group was stable until late filling phase and then increased slightly. At a high infusion rate, the renal pelvic pressures of the sham-operated and control groups were stable until late filling phase and then increased slightly, whereas the renal pelvic pressure in the VUR group steadily increased from mid filling phase. Focal thinning of the tubular epithelium and interstitial widening were observed in certain cortical areas of refluxing kidneys, without inflammatory cell infiltration. Obvious changes in the mean diameters of distal tubules and extracellular matrix volume fractions were observed in two highly refluxing kidneys. High pressure reflux with bladder instability may result in renal cortical changes.

Urinary Tract Infections in Solid Organ Transplant Recipients

Urinary Tract Infections in Solid Organ Transplant Recipients

Severe Hyperphosphatemia in a Newborn With Renal Insufficiency Because of an Erroneous Medical Prescription

We report on an 8-day-old boy with renal failure attributable to bilateral vesicoureteral reflux and dysplastic kidneys. He developed hyperphosphatemia because of his oral phosphate intake. Because he had mild metabolic acidosis, alkaline therapy was planned, but through a medical prescription error he was given a phosphate instead of an alkaline solution. He developed carpopedal spasm, with calcium and phosphate at 5.3mg/dL and 26.0mg/dL, respectively. His phosphate levels gradually decreased via diuretic and calcium gluconate therapy, without dialysis.

Renal cortical involvement in children with first UTI: does it differ in the presence of primary VUR?

The aim of this study was to investigate the influence of vesicoureteral reflux (VUR) on dimercaptosuccinic acid (DMSA) scintigraphic patterns in children with first symptomatic urinary tract infection (UTI). A total of 45 children with the diagnosis of first symptomatic UTI (28 girls, 17 boys, mean age 18 months, range 1 month-11 years) were reviewed. All DMSA scans were obtained within 2 months of bacteriologically proven UTI (median 21 days, mean 26 +/- 21, 14). After the exclusion of the patients with bilateral cortical lesions, 82 renal units were analyzed. The scintigraphic patterns included regional and global description of renal cortical abnormality (normal or decreased differential renal function, regional renal function (RRF), and the number and severity of cortical lesions). Vesicoureteral reflux was detected in 26 (32%) renal units (15 with grade 1-2, 11 with grade 3-4). Renal cortical abnormality was observed in 10 renal units without VUR (10/56, 17%) and 13 renal units with VUR (13/26: 50%). Of the 15 renal units, 5 with grade 1-2 VUR (5/15) and 8 of the 11 renal units with grade 3-4 VUR (8/11) had renal cortical involvement. The most common scintigraphic pattern in the patients without VUR was the preserved RRF (>or=45%) and two or fewer photon-deficient areas. On the other hand, a decreased RRF (<45) associated with cortical lesions was the most frequent finding in patients with refluxing kidneys (8/26, 30%), especially in those with grade 3-4 disease. This investigation showed that the presence of VUR affects DMSA patterns in children with first symptomatic UTI.

Experimental Congenital Vesicoureteral Reflux in Sheep is Associated With Reduced Renal Expression Levels of Aquaporin 1 and 2

Impaired concentrating capacity has been demonstrated in human refluxing kidneys and in kidneys of growing animals with experimental congenital vesicoureteral reflux. Aquaporin water channel proteins are the principal mediators of water homeostasis in the kidney. We examined the impact of experimental congenital vesicoureteral reflux on renal aquaporin protein expression. Vesicoureteral reflux was surgically induced bilaterally in male fetal sheep at 95 days of gestation (term 140 days). Following birth animals received antibiotic prophylaxis, and reflux grades were assessed by fluoroscopic voiding cystogram. After sacrifice at age 6 months 1 kidney of each animal (5 refluxing kidneys, and 3 from normal age and sex matched controls) was retrieved, frozen in liquid nitrogen and used for immunoblotting. The second kidney was perfusion fixed and processed for immunohistochemical analysis. Semiquantitative immunoblotting of inner medulla showed that vesicoureteral reflux was associated with a marked down-regulation in expression of aquaporin 1 (arbitrary units 7.0 +/- 4.3 vs 22.5 +/- 2.8, p <0.05) and aquaporin 2 (5.7 +/- 5.1 vs 24.8 +/- 3.8, p <0.05), which was confirmed by immunocytochemical analysis. Dot blot analysis revealed a homogeneous down-regulation of aquaporin 2 expression throughout the refluxing kidney to 0.029 vs 0.1 in normal kidneys (p = 0.026). Progressively impaired renal concentrating capacity induced by experimental fetal reflux is associated with decreased levels of renal aquaporin 1 and 2 expression. This long-term down-regulation of aquaporin 1 and 2 provides important molecular evidence for a defect in resorptive capacity of water induced by vesicoureteral reflux.

Melatonin and Cranberry Attenuate Infection-induced Apoptotic Renal Damage in a Vesicoureteral Reflux Rabbit Model

Purpose: We evaluated the protective effects of melatonin and cranberry on infection-induced renal damage in a rabbit model of vesicoureteral reflux(VUR). Materials and Methods: Thirty-six New Zealand male rabbits were divided into the following 5 groups: 1) control, 2) VUR, 3) E. coli, 4) cranberry, and 5) melatonin. After creating unilateral VUR, infection was induced by intravesical instillation of an E. coli suspension. Cranberry powder was supplied with the feed. Melatonin was injected into the peritoneal cavity. Three weeks after surgery, the rabbits were sacrificed, and the kidneys were extirpated and examined histopathologically to evaluate inflammation, fibrosis, and tubular changes. Apoptosis in the renal tissue was assessed with a terminal deoxynucleotidyl transferase(TdT)-mediated deoxyuridine triphosphate(dUTP) in situ nick-end labeling(TUNEL) study. Results: Grossly, the refluxing kidney was larger than the contralateral normal kidney, and the refluxing ureter was dilated and tortuous. Microscopic examination of the kidneys from the E. coli group showed an apparent periglomerular mononuclear cell infiltration, tubular dilatation and atrophy, and interstitial fibrosis. The kidneys from the reflux, cranberry, and melatonin groups showed mild mononuclear cell infiltration without interstitial fibrosis. The mean number of apoptotic cells in the kidneys of the E. coli group was significantly higher than that in the control, cranberry, and melatonin groups(p＜0.05), but there was no significant difference between the cranberry and the melatonin groups. Conclusions: This study demonstrates that the balance of apoptotic activity may play a key role in the development of reflux nephropathy. Melatonin and cranberry may prevent infection-induced renal damage by attenuating apoptosis.

Protective effects of cranberries on infection-induced oxidative renal damage in a rabbit model of vesico-ureteric reflux

OBJECTIVE To evaluate the protective effects of cranberry fruit, which have known antioxidant effects, on infection-induced oxidative renal damage in a rabbit model of vesico-ureteric reflux (VUR). MATERIALS AND METHODS In all, 36 New Zealand male rabbits were divided into five groups, with a sham operation in four rabbits serving as the control (group 1). To create unilateral VUR the roof of the left intravesical ureter was incised, and VUR confirmed 2 weeks after surgery. In all, 32 rabbits with VUR were divided into four groups; 2, VUR alone (with sterile urine); 3, a group infected with Escherichia coli; 4, with intravesical E. coli instillation but fed cranberries; and 5, intravesical E. coli instillation plus an intraperitoneal injection with melatonin group. At 3 weeks after surgery the rabbits were killed, the kidneys obtained and examined histopathologically to evaluate inflammation, fibrosis and tubular changes. Oxidative renal damage was evaluated by measuring malondialdehyde in the renal tissue. RESULTS Grossly, the refluxing kidney was larger than the contralateral normal kidney, and the refluxing ureter was dilated and tortuous. Microscopy of tissues from the kidneys in group 3 showed apparent periglomerular mononuclear cell infiltration, tubular dilatation and atrophy, and interstitial fibrosis. The kidneys from groups 2, 4 and 5 showed mild mononuclear cell infiltration with no interstitial fibrosis. The level of malondialdehyde in the kidneys of group 3 was significantly higher than that in group 2, 4 and 5 (P < 0.05); the level in groups 4 and 5 did not differ significantly from that in group 2. CONCLUSIONS This study shows that cranberries have an anti-inflammatory effect through their antioxidant function and might prevent infection-induced oxidative renal damage. Thus, clinically cranberries might be used as a beneficial adjuvant treatment to prevent damage due to pyelonephritis in children with VUR.

Protective effects of cranberries on infection‐induced oxidative renal damage in a rabbit model of vesico‐ureteric reflux

To evaluate the protective effects of cranberry fruit, which have known antioxidant effects, on infection-induced oxidative renal damage in a rabbit model of vesico-ureteric reflux (VUR). In all, 36 New Zealand male rabbits were divided into five groups, with a sham operation in four rabbits serving as the control (group 1). To create unilateral VUR the roof of the left intravesical ureter was incised, and VUR confirmed 2 weeks after surgery. In all, 32 rabbits with VUR were divided into four groups; 2, VUR alone (with sterile urine); 3, a group infected with Escherichia coli; 4, with intravesical E. coli instillation but fed cranberries; and 5, intravesical E. coli instillation plus an intraperitoneal injection with melatonin group. At 3 weeks after surgery the rabbits were killed, the kidneys obtained and examined histopathologically to evaluate inflammation, fibrosis and tubular changes. Oxidative renal damage was evaluated by measuring malondialdehyde in the renal tissue. Grossly, the refluxing kidney was larger than the contralateral normal kidney, and the refluxing ureter was dilated and tortuous. Microscopy of tissues from the kidneys in group 3 showed apparent periglomerular mononuclear cell infiltration, tubular dilatation and atrophy, and interstitial fibrosis. The kidneys from groups 2, 4 and 5 showed mild mononuclear cell infiltration with no interstitial fibrosis. The level of malondialdehyde in the kidneys of group 3 was significantly higher than that in group 2, 4 and 5 (P < 0.05); the level in groups 4 and 5 did not differ significantly from that in group 2. This study shows that cranberries have an anti-inflammatory effect through their antioxidant function and might prevent infection-induced oxidative renal damage. Thus, clinically cranberries might be used as a beneficial adjuvant treatment to prevent damage due to pyelonephritis in children with VUR.

Micturating cystourethrograms are not necessary for all cases of antenatally diagnosed hydronephrosis

Objective Since 1995 we have, at our centre, adopted a selective approach to performing micturating cystourethrograms (MCUGs) on patients with antenatally diagnosed hydronephrosis. This study reviews the outcome of this policy. Methods We carry out MCUGs only if any of the following features are present on ultrasound: bilateral hydronephrosis, ureteric dilatation, renal scarring, bladder wall thickness greater than 5 mm, or presence of a duplex system or ureterocele. Patients with simple unilateral hydronephrosis are excluded, and are managed with 6 months’ trimethoprim prophylaxis and ultrasound surveillance with a minimum of 3 years’ follow up. Results Fifty-five patients were referred with an antenatal diagnosis of hydronephrosis between 1999 and 2002; 26 (47%) did not have an MCUG. Of these, five had increasing hydronephrosis and required surgery for pelvi-ureteric junction obstruction, and three had a multicystic dysplastic kidney on postnatal scanning. In the remaining 18 patients, the hydronephrosis resolved spontaneously, with no renal scars or asymmetry. During follow up, none of these patients had a urinary tract infection. Conclusion We believe that vesico-ureteric reflux in most antenatally diagnosed hydronephrotic kidneys is physiological rather than pathological, and resolves with time without causing long-term renal damage. This is a separate entity from, rather than a precursor of, the pathological symptomatic refluxing kidney in older, mainly female children. Taking a more conservative approach to the postnatal investigation of antenatally diagnosed hydronephrotic kidneys has not resulted in any missed damaged kidneys, but has reduced the number of invasive investigations performed. A careful protocol and detailed postnatal ultrasonography are important to prevent missed pathological cases.

Protective Effects of Cranberry on Infection-induced Oxidative Renal Damage in a Vesicoureteral Reflux Rabbit Model

Purpose: We evaluated the protective effects of cranberry, which is known as a fruit with anti-oxidative effects, on infection-induced oxidative renal damage with using a rabbit vesico-ureteral reflux (VUR) model. Materials and Methods: New Zealand male rabbits were divided into 5 groups (the control group, VUR group, E. coli group, cranberry group and melatonin group). VUR was created and confirmed at 2 weeks after the operation. Infection was induced by intravesical instillation of an E. coli suspension. Cranberry powder was supplied with the feed. Melatonin was injected into the peritoneal cavity. The rabbit kidneys were obtained 3 weeks after the operation. Histopathologic examination was performed to evaluate for inflammation, fibrosis and the tubular change. The oxidative renal damage was evaluated by measuring malondialdehyde (MDA) in the renal tissue. Results: Grossly, the refluxing kidney was larger than the contralateral normal kidney and the refluxing ureter was dilated and tortuous. The microscopic observation of the kidneys from the E. coli group showed apparent periglomerular mononuclear cell infiltration, tubular dilatation and atrophy, and interstitial fibrosis. The kidneys from the reflux group, cranberry group and melatonin group showed mild mononuclear cell infiltration without interstitial fibrosis. The MDA level in the kidneys of the E. coli group was significantly higher than that in the control, cranberry and melatonin groups (p<0.05). The MDA level in the cranberry and melatonin groups didn't significantly differ from that in the sterile group. Conclusions: This study demonstrates that cranberry has an anti-inflammatory effect due to an anti-oxidative function and it may prevent infection-induced oxidative renal damage. But application of cranberry in children with VUR needs more clinical studies. (Korean J Urol 2007;48: 536-541)

Primary Vesicoureteric Reflux and Reflux Nephropathy - New Insights

Primary vesicoureteric reflux was felt to result from a congenitally short mucosal tunnel length with oblique intravescical insertion but more recent data suggest that primary vesicoureteric reflux is often associated with functional urodynamic abnormalities. There is now sound evidence that primary vesicoureteric reflux has a familial basis; most findings suggest a dominant inheritance with incomplete penetrance. Primary vesicoureteric reflux is often associated with kidney damage, mostly referred to as reflux nephropathy. It has been traditionally assumed that in primary vesicoureteric reflux kidney damage results from reflux of infected urine into the renal tissue but recent observations indicate that kidney damage sometimes occurs prenatally. In the overwhelming majority of patients with prenatally acquired renal damage the damage is linked with high-grade vesicoureteric reflux. In conclusion there are two categories of reflux disorder: a reflux associated with an acquired renal scarring secondary to infections and a prenatal high-grade vesicoureteric reflux linked with a congenital nephropathy.

Primary vesicoureteral reflux detected in neonates with a history of fetal renal pelvis dilatation: A prospective clinical and imaging study

To assess the clinical outcome and imaging features of neonatal primary vesicoureteral reflux (VUR). We prospectively followed 43 infants with primary VUR identified from among a cohort of 497 infants with fetal renal pelvis dilatation. Postnatal renal ultrasound (US) examinations were performed at 5 days and 1, 3, 6, 12, and 24 months of life. Voiding cystourethrography was performed in the neonatal period and repeated at 12 and 24 months when VUR was persistent. Two radioisotopic examinations, including a 99mTc-MAG3 renogram and a plasma clearance of Cr-51 EDTA, were performed in all children with high-grade reflux. The incidence of primary VUR in our study group was 9%. Among the 43 patients followed, 11 (26%) had high-grade (IV-V) VUR and 32 (74%) had low-grade VUR. Resolution of reflux occurred in 2 of 11 (18%) patients with high-grade VUR and in 29 of 32 (90.6%) patients with low-grade VUR at age 2 years (P < .001). At age 2 years, 91% of the low-grade refluxing kidneys were normal on US, compared with only 35% of the high-grade refluxing kidneys. Split renal function was within normal range and single-kidney GFR was significantly increased in 13 of the 17 high-grade refluxing kidneys during follow-up. Furthermore, a strong association between dysplasia on US and poor renal function outcome was found. In most infants with VUR, the reflux is of low grade and resolves rapidly. In those children with high-grade VUR, spontaneous resolution is rare at age 2 years, but persistent reflux rarely impairs the maturation of renal function.