Increased expression of substance P receptor-encoding mRNA in bladder biopsies from patients with interstitial cystitis.
OBJECTIVE
To determine whether substance P (SP, also known as neurokinin 1, NK1) receptors are differentially expressed in bladder biopsies from patients with interstitial cystitis (IC) compared with matched controls.


METHODS
Cold-cup biopsies were taken during routine diagnostic cystoscopy. NK1-receptor expression was assessed using a quantitative analysis of NK1-receptor-encoding mRNA in bladder biopsies from patients and controls using in situ hybridization histochemistry (ISHH) combined with autoradiographic image analysis.


RESULTS
Autoradiographic signal indicating the presence of NK1-encoding mRNA was localized to detrusor muscle, urothelium and vascular structures. In the bladder vasculature, the signal was predominantly associated with endothelial cells. NK1 receptor-encoding mRNA within the vascular endothelium was increased in the biopsies obtained from patients with IC.


CONCLUSIONS
Increased levels of NK1 receptor-encoding mRNA within the bladder vascular endothelium suggests the up-regulation of NK1 receptor as a putative factor in the pathogenesis of pain related to IC. Increased responsiveness to SP released from the perivascular sensory terminals may result in a local cascade of neurogenic inflammatory responses which trigger the pathophysiological changes, including pain, characteristic of IC.
Marchand
J E
JE
Department of Anaesthesiology, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA.
Sant
G R
GR
Kream
R M
RM
D000328:Adult; D001706:Biopsy; D018856:Cystitis, Interstitial / Q000378:metabolism* / Q000473:pathology; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D006651:Histocytochemistry; D006801:Humans; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*
D012333:RNA, Messenger; D018040:Receptors, Neurokinin-1