Botulinum-A toxin injections into the detrusor muscle decrease nerve growth factor bladder tissue levels in patients with neurogenic detrusor overactivity

Purpose: We investigated the effects of BTX-A on visceral afferent nerve transmission by measuring bladder tissue NGF levels in patients with neurogenic detrusor overactivity before and after intravesical treatment with BTX-A. We also compared the bladder tissue NGF content with clinical and urodynamic data. Materials and Methods: A total of 23 patients underwent clinical evaluation and urodynamics with detection of the UDC threshold, maximum pressure and maximum cystometric capacity before, and at the 1 and 3-month followups. Endoscopic bladder Wall biopsies were also obtained at the same time points. NGF levels were measured in tissue homogenate by enzyme-linked immunosorbent assay (Promega, Madison, Wisconsin). Results: At 1 and 3 months mean catheterization and incontinent episodes were significantly decreased (p < 0.05 and < 0.001, respectively). On urodynamics we detected a significant increase in the UDC threshold and maximum cystometric capacity, and a significant decrease in UDC maximum pressure at the 1 and 3-month followups compared to baseline (each p < 0.001). At the same time points we detected a significant decrease in NGF bladder tissue content (each p < 0.02). Conclusions: BTX-A intravesical treatment induces a state of NGF deprivation in bladder tissue that persists at least up to 4 months. As caused by BTX-A, the decrease in acetylcholine release at the presynaptic level may induce a decrease in detrusor contractility and in NGF production by the detrusor muscle. Alternatively BTX-A can decrease the bladder level of neurotransmitters that normally modulate NGF production and release

Botulinum toxin Type-A activity in prostate cancer

AIM OF THE STUDY: Botulinum toxin A (BoNT/A) has been recently used in the treatment of benign prostatic hyperplasia due to its apoptotic activity on prostatic epithelium but few data exist on this issue in prostate cancer. Also no information exist on the eventual modulation exerted by the neurotoxin on Phospholipase A2 (PLA2) expression in prostate cancer. The aim of this study was to evaluate the activity of BoNT/A on cell growth and expression of PLA2 in prostate cancer lines. MATERIALS AND METHODS: PC-3 and LNCaP cell lines were exposed to BoNT/A (Xeomin®), different doses and time of exposure. Presence of SV2 receptors (SV2-A and SV2-B) for the neurotoxin was also investigated. The expression of P-Ser505-cPLA2-α (phosphorylated enzyme) was performed immunofluorescence. RESULTS: After 96 hours of BoNT/A administration a 20% reduction of cell growth in LNCaP and 25% in PC-3 were observed. SV-2 receptors were expressed in both cell lines. No cPLA2-α total expression was found in LnCaP. In PC-3 there was a high expression of cPLA2-α total which was not modified after BoNT/A treatment. In both LNCap and PC-3 the expression of P-Ser505-cPLA2-α (phosphorylated enzyme) increases significantly after treatment with [10 U/ml] of BoNT/A. CONCLUSIONS: LNCaP and PC-3 cell lines are sensitive to treatment with BoNT/A which probably enters the cells by SV2 receptors. The increase in the phosphorylated form of cPLA2-a, induced by BoNT/A may represent one mechanism by which the toxin reduces cell growth and proliferation

OnabotulinumtoxinA intradetrusorial injections modulates bladder expression of NGF, TrkA, p75 and TRPV1 in patients with detrusor overactivity

OnabotulinumtoxinA (BoNT/A) intradetrusorially injected in patients with neurogenic and idiopathic detrusor overactivity (DO) significantly decreased NGF levels and TRPV1 expression in bladder and urine. To date no information exist on gene expression of TrkA and p75 (NGF receptors) in bladder tissues of patients treated with BoNT/A. In this study we investigated BoNT/A-induced changes in gene expression of TRKA and p75, and of NGF and TRPV1 in bladder tissue of patients with neurogenic and idiopathic DO. MATERIAL & METHODS: 18 patients with neurogenic DO and 7 with idiopathic DO underwent clinical, urodynamic and cystoscopic evaluation with bladder biopsy specimen before (T0) and one month (T1) after intradetrusor BoNT/A injection (300 U in neurogenic DO and 100 U in idiopathic DO). Changes in gene expression of NGF, TRPV1, TRKA and p75 were investigated with Real Time PCR (qPCR) at T0 and T1. Changes in NGF-protein content (ng/mg) were measured by ELISA assay at T0 and T1. Data are expressed as post/pre ratio. RESULTS: Clinical and urodynamic significant improvements were observed in all patients at T1. We observed a significant increase in NGF (1.68±0.2 folds), TRPV1 (1.83±0.3 folds), TRKA (1.36±0.2 folds) and p75 (2.02±0.4 folds) expression in all patients and a significant decrease in NGF protein bladder content (689±113 ng/total mg vs. 252±67 ng/total mg). (Fig. 1) We found a linear correlation between changes in NGF and TRKA (p=0.005), NGF and TRPV1 (p=0.02), TRKA and TRPV1 (p=0.0002). Patients injected with 300 BoNT/A U had a higher increase in NGF, TRPV1 and TRKA expression than those who received 100 U. No significant correlation was found between p75 and changes in NGF expression (p=0.17). CONCLUSIONS: We confirm the previously reported activity of BoNT/A in reducing NGF bladder tissue content in patients with neurogenic and idiopathic DO. The novel finding of this study was the significant neurotoxin- induced up-regulation of bladder NGF, TrkA and TRPV1 in the short time. This may represent a compensatory change aimed at re-establishing NGF bladder levels and activity. The linear correlation existing among NGF, TrkA and TRPV1 overexpression after treatment demonstrated a strictly linked activity of these transmitters/receptors. p75 expression was highly variable and reflected the fact it is a "pan-neuroreceptor"

Onabotulinumtoxin-A intradetrusorial injections modulate bladder expression of NGF, TrkA, p75 and TRPV1 in patients with detrusor overactivity

How onabotulinumtoxinA (onab/A) injected in the detrusor muscle improves detrusor overactivity (DO) is still a matter of debate. Nerve growth factor (NGF) seems to play a role in determining urgency and DO. Recent studies showed that NGF decreases in patients with DO who respond to onab/A treatment. We investigated onab/A-induced changes on gene expression of NGF, TRPV1, TrkA and p75 in bladder wall tissue of patients affected by neurogenic and idiopathic DO. Twenty-five patients (18 with neurogenic DO and 7 with idiopathic DO) received onab/A injections into the detrusor muscle. Urodynamic studies and cystoscopies with sampling of the bladder wall were performed before and 1 month after onab/A injections. Onab/A-induced changes in urodynamic variables (first volume and maximum pressure of uninhibited detrusor contractions and maximum cystometric capacity) and NGF, TRPV1, TRKA, p75 gene expression by means of quantitative Real Time-Polymerase Chain Reaction. NGF protein levels were assessed in tissue homogenates by enzyme-linked immunosorbent assay. Onab/A significantly improved urodynamic findings (as shown by the increase in maximum cystometric capacity), decreased the bladder tissue levels of NGF protein and significantly increased NGF, TrkA, p75 and TRPV1 gene expression independently from the etiology of DO. No significant correlation has been found between NGF down-regulation and the increase in MCC. Correlations between NGF gene expression and NGF receptors' gene expression were influenced by onab/A dosages. In the short time follow-up, onab/A decreases NGF protein levels and increases NGF and associated receptors' gene expression possibly by inhibiting NGF release. Further studies with longer follow-up will clarify time course of onab/A-induced modifications in NGF expression

Group IIA secretory phospholipase A2 (GIIA) mediates apoptotic death during NMDA receptor activation in rat primary cortical neurons

Phospholipases A2 (PLA2) participate in neuronal death signalling pathways because of their ability to release lipid mediators, although the contribution of each isoform and mechanism of neurotoxicity are still elusive. Using a novel fluorogenic method to assess changes in a PLA 2 activity by flow cytometry, here we show that the group IIA secretory phospholipase A2 isoform (GIIA) was specifically activated in cortical neurons following stimulation of N-methyl-d-aspartate glutamate receptor subtype (NMDAR). For activation, GIIA required Ca2+ and reactive oxygen/nitrogen species, and inhibition of its activity fully prevented NMDAR-mediated neuronal apoptotic death. Superoxide, nitric oxide or peroxynitrite donors stimulated GIIA activity, which mediated neuronal death. Intriguingly, we also found that GIIA activity induced mitochondrial superoxide production after NMDAR stimulation. These results reveal a novel role for GIIA in excitotoxicity both as target and producer of superoxide in a positive-loop of activation that may contribute to the propagation of neurodegeneration