Urodynamic and histological changes in a sterile rabbit vesicoureteral reflux model

Magnetic Agarose Microspheres/Hyaluronic Acid Hydrogel as a Trackable Bulking Agent for Vesicoureteral Reflux Treatment

Vesicoureteral reflux (VUR) is one of the most common congenital anomalies in the kidney and the urinary tract. Endoscopic subureteral injection of a bulking agent has become popular in VUR treatment due to its high success rates, few complications, and a straightforward procedure. In this study, a novel magnetic bulking agent was prepared by embedding Fe₃O₄ magnetic nanoparticles in cross-linked agarose microspheres with diameters of 80–250 μm and dispersing the magnetic microspheres in a hyaluronic acid hydrogel. The bulking agent has good biocompatibility and biosecurity validated by the tests of cytotoxicity, in vitro genotoxicity, animal irritation, skin sensitization, acute systemic toxicity, and pathological analysis after the injection of the bulking agent extract solution into healthy mice as well as injection of the bulking agent into VUR rabbits. The VUR rabbits were created by incising the roof of the intravesical ureter to enlarge the ureteral orifice. The success rate of the bulking agent in treating VUR rabbits using a subureteral transurethral injection technique was 67% (4/6) or 80% (4/5, excluding the unfinished rabbit), and no migrated particles were found in the organs of the rabbits. The transverse relaxation rate of the bulking agent was 104 mM⁻¹s⁻¹. After injection, the bulking agent was long-term trackable through magnetic resonance imaging that can help clinicians to inspect the VUR treatment effect. For the first time, this study demonstrates that the bulking agent with a long-term stable tracer is promising for endoscopic VUR treatment.

Simplified Bioprinting-Based 3D Cell Culture Infection Models for Virus Detection

Studies of virus-host interactions in vitro may be hindered by biological characteristics of conventional monolayer cell cultures that differ from in vivo infection. Three-dimensional (3D) cell cultures show more in vivo-like characteristics and may represent a promising alternative for characterisation of infections. In this study, we established easy-to-handle cell culture platforms based on bioprinted 3D matrices for virus detection and characterisation. Different cell types were cultivated on these matrices and characterised for tissue-like growth characteristics regarding cell morphology and polarisation. Cells developed an in vivo-like morphology and long-term cultivation was possible on the matrices. Cell cultures were infected with viruses which differed in host range, tissue tropism, cytopathogenicity, and genomic organisation and virus morphology. Infections were characterised on molecular and imaging level. The transparent matrix substance allowed easy optical monitoring of cells and infection even via live-cell microscopy. In conclusion, we established an enhanced, standardised, easy-to-handle bioprinted 3D-cell culture system. The infection models are suitable for sensitive monitoring and characterisation of virus-host interactions and replication of different viruses under physiologically relevant conditions. Individual cell culture models can further be combined to a multicellular array. This generates a potent diagnostic tool for propagation and characterisation of viruses from diagnostic samples.

Validity of a disposable catheter to drain urine overnight in neurogenic bladder

BACKGROUND

Overnight catheter drainage (OCD) is introduced to avoid overdistention of the bladder at night-time when clean intermittent catheterization proves ineffective for daytime management of neurogenic bladder. We adopted OCD using disposable silicone no-balloon (DSnB) catheters, with the distal end outside the body opening into diapers. OCD using DSnB catheter, however, had risks of retrograde bacterial contamination. Therefore, in this study, the validity of equipping DSnB catheters with check valves to prevent retrograde bacterial contamination was examined.

METHODS

For the in vitro study, excised saline-filled swine bladders were drained using DSnB catheters with or without check valves, and the time required for intravesical pressure to reach 5 cmH₂ O was measured. For the in vivo study, in cross-over experiments comparing DSnB catheters with and without check valves, OCD using DSnB catheters for 10 h was performed in rabbits under analgesia. Bacterial growth from urine samples before and after OCD and residual urine volume were examined.

RESULTS

For the in vitro experiment, the median drainage time was 368.2 s (range, 88-1,085 s) and 344.7 s (range, 28-840 s) with and without check valves, respectively (n = 6), which was not significantly different. For the in vivo experiment, in cross-over experiments (n = 8) new bacterial growth rates after OCD did not differ, and median residual urine volume was 17.1 mL (range, 0-75 mL) and 1.2 mL (range, 0-5 mL) with and without check valves, respectively (P = 0.055).

CONCLUSIONS

Installing a check valve in the DSnB catheter did not decrease new bacterial growth, while tending to increase residual urine volume. DSnB catheters without check valves appear to be better for continuous drainage of urine from bladder.

Transplantation of mature adipocyte-derived dedifferentiated fat cells for the treatment of vesicoureteral reflux in a rat model

PURPOSE

Autologous cells potentially provide an ideal injectable substance for management in vesicoureteral reflux (VUR). The aim of this study is to examine the effects of mature adipocyte-derived dedifferentiated fat (DFAT) cell transplantation on VUR in a rat bladder pressurization-induced VUR model.

METHODS

To create VUR, Sprague-Dawley rats underwent urethral clamping and placement of cystostomy followed by intravesical pressurization. Rat DFAT cells (1 × 10⁶ cells, DFAT group, n = 5) or saline (control group, n = 5) was then injected into the bilateral vesicoureteral junctions. Two weeks later, VUR grade was evaluated on cystography. The number of apoptotic cells in the renal pelvic urothelium, the ureteral inner/outer diameter ratio and the area of connective tissue in the posterior bladder wall were measured.

RESULTS

The reflux grade in the DFAT group was significantly lower than that in the control group. The number of apoptotic cells in the renal pelvic urothelium, ureteral inner/outer diameter ratio and connective tissue area in DFAT group were significantly lower in comparison with the control group.

CONCLUSIONS

DFAT cell transplantation improved VUR and exerted nephroprotective effects in a rat VUR model.

The Biocompatibility of a Cellulose Exopolysaccharide Implant in the Rabbit Bladder When Compared With Dextranomer Microspheres Plus Hyaluronic Acid

OBJECTIVE

To evaluate biocompatibility of a cellulosic exopolysaccharide (CEC) as bulking agent in rabbit urinary bladder.

MATERIALS AND METHODS

The experimental study was developed at the Nucleus for Experimental Surgery or UFPE. The new agent was injected into the bladder of the adult rabbits using a small abdominal incision. Animals were injected with 0.2 mL of dextranomer microspheres (Dx) plus hyaluronic acid and CEC. The animals were studied after 3 days (G1), 90 days (G2), and 11 months (G3). The biocompatibility was evaluated according to the histologic parameters (presence of blood vessels, inflammatory reaction, and collagen deposition) by a quantitative analysis. The Student paired t test was used for continuous variables, and the scores were compared through the chi-square test.

RESULTS

Both materials were structurally homogeneous and free from inflammatory cells or blood vessels (G1). In 3-month samples (G2), CEC areas were densely invaded by fibroblasts and blood vessels. Dx areas were fragmented but still homogeneous and free from cells or blood vessels. Samples from 3 and 11 months showed a significant difference in favor of CEC especially concerning preservation of material in the implant site, as well as the presence of neovascularization. This experimental study represents a positive outcome in terms of reflux resolution in the long term. Further studies may be necessary to confirm its efficacy when in clinical use.

CONCLUSION

The CEC exhibited low inflammatory response and integrated with the host tissue better than Dx in the long-term follow-up.

Diffusion weighted magnetic resonance imaging of kidneys in children with vesicoureteral reflux

PURPOSE

The apparent diffusion coefficient (ADC) which obtain from diffusion-weighted magnetic resonance imaging (DWI), is a quantitative parameter representing the renal function and parenchymal damage in some renal disorders. The primary aim of this study was to investigate whether renal tissue alterations associated with vesicoureteral reflux (VUR) can be displayed by DWI. The secondary aim was to assess how ADC values change with age in kidneys with and without VUR.

MATERIALS AND METHODS

This prospective study included 46 patients (8 boys, 38 girls; mean age 7.3 ± 4.2; range 1-15 years) with VUR and 54 control subjects (21 boys, 33 girls; mean age 7.7 ± 5.2; range 1-17 years). All subjects underwent DWI of the kidneys using b value of 600s/mm(2) in addition to MR urography. The ADC values of 71 kidneys with VUR were compared with those of 81 kidneys without VUR.

RESULTS

The mean ADC values were (1.93 ± 0.36)×10(-3)mm(2)/s, (1.97 ± 0.24)× 10(-3)mm(2)/s, (1.83 ± 0.37)× 10(-3)mm(2)/s, (1.98 ± 0.20)×10(-3)mm(2)/s and (2.08 ± 0.42)× 10(-3)mm(2)/s in normal kidneys, and in those with grade 1, grade 2, grade 3 and grade 4 VUR, respectively. There was no significant difference in ADC values between kidneys with and without VUR. There was a significant positive correlation between the age and ADC values both in kidneys with and without VUR (r=0.79, p<0.001 and r=0.82; p<0.001, respectively).

CONCLUSION

DWI does not reveal probable parenchymal alterations in reflux nephropathy. ADC values increase with age during childhood not only in normal kidneys but also in kidneys with VUR.

Urinary proteome analysis to exclude severe vesicoureteral reflux

OBJECTIVES

High-grade vesicoureteral reflux (VUR, grade IV or V) is a risk factor for renal scarring, impaired renal function, and arterial hypertension. Voiding cystourethrography is the gold standard for detecting the severity of VUR. High-grade VUR is present in the minority of children with urinary tract infection (UTI), thus exposing the majority to invasive diagnostics that have no surgical consequence. We therefore aimed at establishing a noninvasive test to identify children with high-grade VUR.

METHODS

In a case-control study, a specific urinary proteome pattern was established by capillary electrophoresis coupled to mass spectrometry in 18 patients with primary VUR grade IV or V, distinguishing these from 19 patients without VUR after UTI. This proteome pattern was independently validated in a blinded cohort of 17 patients with VUR grade IV or V and 19 patients without VUR.

RESULTS

Sensitivity in detecting VUR grade IV or V in the blinded study was 88%, specificity was 79%. The test's accuracy was independent of age, gender, and grade of VUR in the contralateral kidney. The odds ratio of suffering from VUR grade IV or V when tested positive was 28 (95% confidence interval: 4.5 to 176.0).

CONCLUSIONS

This noninvasive test is ready for prospective validation in large cohorts with the aim of identifying those children with UTI and hydronephrosis in need of further invasive diagnostics, such as voiding cystourethrography, thus sparing most children without pathologic urinary proteome patterns from additional diagnostics.

Suprapubic bladder catheterization of male spinal-cord-injured Sprague-Dawley rats

The rat spinal-cord-injury (SCI) model is widely used to study the pathologic mechanisms that contribute to sensory and motor dysfunction in humans. This model is thought to mimic many of the negative outcomes experienced by humans after spinal contusion injury. We theorized that manual bladder expression contributed to the kidney and bladder lesions reported in previous studies using the rat SCI model. In the present study, rats were surgically implanted with bladder catheters after spinal contusion injury to provide continuous drainage of urine. After 72 h, the rats were euthanized and their kidneys and bladders examined histologically. BUN, serum creatinine, and urine protein were compared at 0 and 72 h after surgery. Kidney and bladder lesions were similar in SCI rats with and without implanted bladder catheters. BUN at 72 h was higher than baseline values in both groups, whereas serum creatinine was higher at 72 h compared with baseline values only in the catheterized rats. These findings indicate that suprapubic bladder catheterization does not reduce hydronephrosis in SCI rats and that the standard of care for bladder evacuation should continue to be manual expression of urine.