Aims of Study:
Multiple sclerosis (MS) is a chronic inflamation-demielinization process of the nervous system . Lower urinary tract dysfunctions occurs in about 96% of MS patients, in 12% they occurs at the very beginning phase of the MS or even they precede the onset of MS itself. The most common functional finding in these patients is detrussor hyper-reflexia combined in some cases with detrussor-sphincter dyssynergia. It is suggested, that hyper-reflexia in patients with MS may be due to activation of C-fibers afferents. In our pilot study we decided to evaluate the functional status of the lower urinary tract in the patients with clinically proven MS and to check whether it may correlate with the innervation pattern of the urinary bladder.

Material and Methods:
10 patients (6 females, 2 males, mean age 37.5) with clinically proven MS were included in the study. All patients underwent three-channel subtraction cystometry combined with the EMG recording. Afterwards patients were anaesthetized and bladder biopsies were taken from the bladder trigone using a rigid cystoscope and biopsy forceps. A mean of two biopsies were obtained from each patient. The specimens were fixed in 4% paraformaldehyde in phosphate buffered saline (PBS) for 2 hours, rinsed in PBS and stored in 18% sucrose solution. 10-µm-thick cryostat sections of biopsies samples were cut at the cryostat and mounted on chrome-alum-gelatine-coated glass slides. In order to reduce the non-specific background autofluorescence and non-specific staining, the sections were incubated for 10 sec in a freshly prepared mixture of 0.5 N H2SO4 and KMnO4 in distilled water , thoroughly washed in distilled water (3x2 min), and transferred in 0.1 M PBS for 10 min. Specimens were then incubated overnight with rat anti-substance P (SP) and rabbit anti calcitonin gene-related peptide (CGRP) antiserum. The immunoreaction was then visualised by incubation of sections with FITC-conjugated goat anti-rat or goat anti-rabbit IgG.

Results:
Based on the urodynamic studies two distinct groups could be distinguished. Group one (n=6) was characterized by a pronounced hypersensitivity, lowered capacity and compliance as well as by high maximum pressure of unstable detrussor (Pdet inst): volume at first sensation (FS)-98ml, Pdet/FS-23cm H2O; Cyscap-217ml, Pdet/Cyscap-51 cm H2O; Pdetinst-69cm H2O /mean values/. During voiding these patients had functional outflow obstruction caused by detrussor-sphincter dyssynergia ( Q max 10.8 ml/s, degree of obstruction according to Schaffer - 2.4, post-void residual - 30 ml, mean values). In the second group ( n=4 ) sensation capacity and compliance were normal and maximum pressure of unstable detrussor low (28cm H2O in a mean). Voiding phase was characterized by a maximum flow rate of 9.8ml/s, degree of obstruction 2.6 and post-void residual 135 ml /mean values/. Immunohistochemical staining of the bladder biopsies revealed moderate density of CGRP and SP containing nerve fibers in the suburothelial and submucosal layers of the group one patients urinary bladders. In the bladder biopsies taken from the group two patients single SP and CGRP containing nerve fibers were observed in the suburothelium, in the submucosal layer SP and CGRP positive nerve fibers were observed sporadically.

Discussion:
Our preliminary results demonstrate that in the MS patients functional disturbances of the lower urinary tract are reflected in the innervation pattern of the urinary bladder. It is well known that at least some of the CGRP and SP containing nerve fibers are sensory non-myelinated C-fibers responsible for an altered micturitional reflex that initiates detrussor hyper-reflexia. On the other hand, detrussor hyper-reflexia could be successfully managed by intravesical capsaicin or resiniferatoxin instillations. There is however a population of the patients who are not responding to this treatment. Our preliminary data may suggest that CGRP- and SP-containing nerve fibers density in the urinary bladder could play a role in the prediction of an outcome after capsaicin or resiniferotoxin treatment.

References:
1.Multiple sclerosis and the urologist. J. Urol. 161, 743-757, 1999.
2.The effect of intravesical capsaicin on the suburothelial innervation in patients with detrussor hyper-reflexia. BJU International, 85, 238-245, 2000