The effect of intravesical electrical stimulation on bladder function and synaptic neurotransmission in the rat spinal cord after spinal cord injury.

OBJECTIVE: To investigate the effects of intravesical electrical stimulation (IVES) on bladder function and synaptic neurotransmission in the lumbosacral spinal cord in the spinalized rat, as the clinical benefits of IVES in patients with increased residual urine or reduced bladder capacity have been reported but studies on the mechanism of IVES have mainly focused on bladder A delta afferents in central nervous system-intact rats. MATERIALS AND METHODS: In all, 30 female Sprague-Dawley rats were divided equally into three groups: normal control rats, sham-stimulated spinalized rats and IVES-treated spinalized rats. IVES was started 5 weeks after spinal cord injury (SCI) and was performed 20 min a day for 5 consecutive days. At 7 days after IVES, conscious filling cystometry was performed. Sections from the L6 and S1 spinal cord segments were examined for n-methyl-d-aspartic acid receptor 1 (NMDAR1) subunit and gamma-aminobutyric acid (GABA) immunoactivity. RESULTS: In IVES-treated spinalized rats, the number and maximal pressure of nonvoiding detrusor contractions were significantly less than in sham-stimulated spinalized rats. The mean maximal voiding pressure was also lower in IVES-treated than in sham-stimulated spinalized rats. IVES significantly reduced the interval between voiding contractions compared with the untreated spinalized rats. There was an overall increase in NMDAR1 immunoactivity after SCI, which was significantly lower in IVES-treated spinalized rats. Immunoactivity of GABA after SCI was significantly lower than in the control group and was significantly higher in IVES-treated spinalized rats. CONCLUSION: Our results suggest that IVES might affect voiding contractions in addition to inhibiting C-fibre activity and that IVES seems to have a more complex effect on the bladder control pathway. For synaptic neurotransmission in the spinal cord, IVES could possibly shift the balance between excitation and inhibition towards inhibition.

Cyst formation in kidney via B-Raf signaling in the PKD2 transgenic mice.

The pathogenic mechanisms of human autosomal dominant polycystic kidney disease (ADPKD) have been well known to include the mutational inactivation of PKD2. Although haploinsufficiency and loss of heterozygosity at the Pkd2 locus can cause cyst formation in mice, polycystin-2 is frequently expressed in the renal cyst of human ADPKD, raising the possibility that deregulated activation of PKD2 may be associated with the cystogenesis of human ADPKD. To determine whether increased PKD2 expression is physiologically pathogenic, we generated PKD2-overexpressing transgenic mice. These mice developed typical renal cysts and an increase of proliferation and apoptosis, which are reflective of the human ADPKD phenotype. These manifestations were first observed at six months, and progressed with age. In addition, we found that ERK activation was induced by PKD2 overexpression via B-Raf signaling, providing a possible molecular mechanism of cystogenesis. In PKD2 transgenic mice, B-Raf/MEK/ERK sequential signaling was up-regulated. Additionally, the transgenic human polycystin-2 partially rescues the lethality of Pkd2 knock-out mice and therefore demonstrates that the transgene generated a functional product. Functional strengthening or deregulated activation of PKD2 may be a direct cause of ADPKD. The present study provides evidence for an in vivo role of overexpressed PKD2 in cyst formation. This transgenic mouse model should provide new insights into the pathogenic mechanism of human ADPKD.

Gene discovery analysis from mouse embryonic stem cells based on time course microarray data.

An embryonic stem cell is a powerful tool for investigation of early development in vitro. The study of embryonic stem cell mediated neuronal differentiation allows for improved understanding of the mechanisms involved in embryonic neuronal development. We investigated expression profile changes using time course cDNA microarray to identify clues for the signaling network of neuronal differentiation. For the short time course microarray data, pattern analysis based on the quadratic regression method is an effective approach for identification and classification of a variety of expressed genes that have biological relevance. We studied the expression patterns, at each of 5 stages, after neuronal induction at the mRNA level of embryonic stem cells using the quadratic regression method for pattern analysis. As a result, a total of 316 genes (3.1%) including 166 (1.7%) informative genes in 8 possible expression patterns were identified by pattern analysis. Among the selected genes associated with neurological system, all three genes showing linearly increasing pattern over time, and one gene showing decreasing pattern over time, were verified by RT-PCR. Therefore, an increase in gene expression over time, in a linear pattern, may be associated with embryonic development. The genes: Tcfap2c, Ttr, Wnt3a, Btg2 and Foxk1 detected by pattern analysis, and verified by RT-PCR simultaneously, may be candidate markers associated with the development of the nervous system. Our study shows that pattern analysis, using the quadratic regression method, is very useful for investigation of time course cDNA microarray data. The pattern analysis used in this study has biological significance for the study of embryonic stem cells.

Extracorporeal pelvic floor magnetic stimulation in children with voiding dysfunction.

OBJECTIVE: To determine the effect of extracorporeal pelvic floor magnetic stimulation in children with an overactive bladder, as although such stimulation is an effective treatment for voiding dysfunction such as urge incontinence (UI) and urgency-frequency syndrome, experience in children is scarce. PATIENTS AND METHODS: This prospective study included 42 children diagnosed with an overactive bladder, based on urodynamic or video-urodynamic study; a complete follow-up was available in 34. The children were grouped into those with UI only, not monosymptomatic nocturnal enuresis (nMNE), or MNE, according to their symptoms. Clinical variables were assessed by recording a voiding and nocturnal enuresis diary before and after magnetic stimulation, the latter being administered twice a week for 4 weeks using a size-adjusted magnetic chair (each session took 20 min). RESULTS: The UI only and nMNE group had a significant decrease in voiding frequency and frequency of UI (P < 0.05); the MNE group also had a significant decrease in voiding frequency (P < 0.05). There was a significant increase in functional bladder capacity in all groups (P < 0.05) but no significant decrease in the mean volume and frequency of NE in the nMNE and MNE groups (P > 0.05). CONCLUSIONS: Extracorporeal pelvic floor magnetic stimulation has an acute effect on voiding dysfunction such as urge syndrome in children. However, controlled studies with a sham-stimulation group and various durations of stimulation are necessary for its application as a primary treatment for voiding dysfunction in children.

Elastin content of the renal pelvis and ureter determines post-pyeloplasty recovery.

PURPOSE: We evaluated the collagen-to-smooth muscle tissue matrix ratio and percentage of elastin in the renal pelvis, ureteropelvic junction (UPJ) and ureter, and compared these findings with the degree of obstruction, patient age and post-pyeloplasty renal recovery. MATERIALS AND METHODS: We analyzed histological sections from 75 patients with UPJ obstruction. Nine patients were excluded owing to bilateral UPJ obstruction and an improper specimen. We divided the specimen obtained from pyeloplasty into 3 parts, namely the renal pelvis above the obstruction, the obstructed UPJ portion and the ureter below the obstruction. To examine the collagen and smooth muscle, sections were stained using Masson's trichrome, and elastic van Giesson stain was used for elastin, smooth muscle and collagen. Collagen, smooth muscle and elastin populations were identified, and the tissue matrix ratio and percentage of elastin were calculated by color image analysis. RESULTS: In patients with lower ratios of collagen-to-smooth muscle in the UPJ proper hydronephrosis was more improved postoperatively (p = 0.049). In patients with a lower percentage of elastin in the renal pelvis, UPJ and ureter hydronephrosis was more improved postoperatively (p <0.0001). CONCLUSIONS: Because the UPJ portion was resected during pyeloplasty, the renal pelvis and the ureter remaining after pyeloplasty are likely to be related to improved hydronephrosis. A higher percentage of elastin in the renal pelvis and ureter contributes to inelasticity and low compliance, and results in a slower recovery from hydronephrosis after pyeloplasty.

Chondrogenic differentiation of human mesenchymal stem cells using a thermosensitive poly(N-isopropylacrylamide) and water-soluble chitosan copolymer.

Poly(N-isopropylacrylamide) (PNIPAAm) is known to be thermally responsive material and has a lower critical solution temperature (LCST, 32 degrees C) at which a macromolecular transition from a hydrophilic to a hydrophobic structure occurs. Chitosan is a useful natural polymeric biomaterial due to its biocompatibility and biodegradable properties. It has good characteristics for cell attachment, proliferation and viability. The aim of this study was to assess the ability to differentiate from mesenchymal stem cells (MSCs) to chondrocytes and mass formation using a newly developed injectable material, a thermosensitive (water-soluble chitosan-g-PNIPAAm) gel, and evaluate cartilage formation in vivo after injecting a cell-thermosensitive gel complex. The MSCs were cultured in the chitosan-PNIPAAm in vitro. Fluorescence-activated cell sort analysis, viability test, collagen type I, II, X formation and the aggrecan levels were examined. These cultured cells can be easily recovered from a copolymer gel by simply lowering the temperature. An animal study was performed to assess cartilage formation in the submucosal layer of the bladder of rabbits. The cartilage formation could be detected. This can be used to treat vesicoureteral reflux or reflux esophagitis by the effective mass effect. This is a simple method (sol-gel technique in LCST), and good cartilage formation occurs in the bladder tissue.

Intravesical electrical stimulation improves neurogenic bowel dysfunction in children with spina bifida.

PURPOSE: We observed concomitant improvement in fecal incontinence in children with myelomeningocele undergoing intravesical electrical stimulation (IVES) to decrease uninhibited bladder contractions and increase bladder capacity and/or bladder sensation. We retrospectively reviewed the effect of intravesical electrical stimulation on neurogenic bowel dysfunction in these children. MATERIALS AND METHODS: A total of 9 boys and 15 girls 3.9 to 13.2 years old (mean age 8.1) completed a mean of 30.3 daily sessions (range 10 to 69) of IVES. Evaluation forms were used to record frequency of fecal incontinence, daily bowel movement and diaper use before and after IVES. RESULTS: The mean number of overall fecal incontinence episodes decreased significantly from 7.36 to 4.8 a week after IVES (p <0.05). Greater than 50% decrease in the episodes of fecal incontinence was observed in 75% of the patients. However, there was no significant change in the number of daily bowel movements before (1.8 daily) and after (1.55 daily) IVES. CONCLUSIONS: These results demonstrate the therapeutic effect of IVES in children with neurogenic bowel dysfunction and spina bifida. We believe that IVES is another viable option for controlling fecal incontinence in these children.

Sensory neuronal change after intravesical electrical stimulation in spinailized rat.

The clinical benefits of intravesical electrical stimulation (IVES) in patients with increased residual urine or reduced bladder capacity have been reported. However, studies on the underlying mechanism of IVES has been limited to the Adelta afferent and parasympathetic neurons. This study investigated the changes in the calcitonin gene-related peptide (CGRP), substance P (SP), and nitric oxide synthase (NOS) expression in the thoracolumbar and lumbosacral dorsal root ganglia (DRG) of spinalized rats to determine the effect of IVES on the C fiber afferent nerve. Forty Sprague-Dawley rats were divided into normal controls (n=10); IVES treated normal rats (n=10), spinalized rats (n=10), and IVES treated spinalized rats (n=10). IVES was performed for 2 weeks (5 days a week). IVES was started 3 weeks after spinalization in the spinalized animals. All animals had the DRG removed at the thoracolumbar (T13-L2) and lumbosacral (L5-S1) level. Changes in the CGRP, SP and n-NOS levels at the DRG were measured by western-blot analysis. The relative density of the CGRP and SP following spinalization was significantly higher compared to the controls in both the T13-L2 and L5-S1 DRG. However, IVES in the spinalized rat significantly decreased the relative density of the CGRP and SP compared to the rats with spinalization alone. A significant increase in the relative density of n-NOS was detected in the L5-S1 DRG following spinalization. However, the density of n-NOS was significantly lower after IVES in both the T13-L2 and L5-S1 DRGs. In conclusion, IVES significantly reduced the CGRP, SP and n-NOS levels in the DRG of spinalized rats. CGRP, SP and n-NOS are the main factors that contribute to the hyperexcitability of the micturition reflex after spinal cord injury. These results suggest that the bladder C fiber afferent is also involved in modulating the micturition reflex by IVES.