In a feline interstitial cystitis (FIC) model researchers identified an increase in nerve growth factor (NGF) and substance P (SP) in urothelium. The elevated NGF expression by FIC urothelium might be a possible cause for the increased cell body size of DRG neurons observed in these cats with FIC.
In the spinal cord, astrocytic GFAP immuno-intensity was significantly elevated and there was evidence for co-expression of the primitive intermediate filament, nestin in regions of the FIC S1 cord (superficial and deep dorsal horn, central canal and laminae V-VIl) that receive input from pelvic afferents.
The authors concluded:
Though urothelial cells are often viewed as bystanders in the processing of visceral sensation, these and other findings support the view that these cells function as primary transducers of some physical and chemical stimuli. In addition, the pronounced activation of spinal cord astrocytes in an animal model for bladder pain syndrome (BPS) may play an important role in the pain syndrome and open up new potential approaches for drug intervention.