One area Marcia Barinaga does not touch on in her News Focus article “Soft money's hard realities” (22 Sept., p. [2024][1]) is that of arbitrary funding cuts by the National Institutes of Health in their grant budgets. As a former “soft money” faculty person (I gave up after 15 years), these

Previously, we described an animal model for interstitial cystitis (IC), experimental autoimmune cystitis (EAC) [Luber-Narod et al. Urol Res 24:367]. Further characterization of animals with EAC indicates that peak and mean urinary frequency are elevated compared with sham-injected controls and that the disease progresses with at least two cycles of exacerbations and remissions. We had shown evidence suggesting EAC to be autoimmune in nature. In this paper, we identify serum autoantibodies from 9/10 EAC animals which bind to a protein specific to rat bladder with a relative molecular weight of 12-kDa. Such autoantibodies are absent in 12/13 normal and sham-injected animals as well as animals which fail to develop EAC despite disease induction. These findings suggest that EAC is a reproducible model of cyclical increases of urinary frequency, and that a 12-kDa antigen is the target of autoantibodies which correlate with those elevations. Identification of this target antigen may explain the pathogenesis of increased urinary frequency in these animals and potentially in IC as well.

In the absence of Na+, 125I-Neurotensin (125I-NT) binding to the Neurotensin receptor (NTR) produces a stable noncovalent 125I-NT-NTR complex whose dissociation rate is extremely low even after the addition of 1 microM NT, 100 microM SR48692 (antagonist), 100 microM GPPNHP or 100 mM NaCl. Lowering the medium pH to 4.5 enhances the process (approximately 70% in 10 minutes). Labeling by photoactivatable 125I-Tyr3-Azo4-NT identifies a approximately 50 KD Mr band along with several other minor components. Interestingly, the labeling intensity is drastically reduced when binding is performed in the presence of Na+ or GPPNHP. However, a minor reduction is noticed when Na+ or GPPNHP is added to the medium after binding. The binding kinetics indicates that Na+ lowers the rate of 125I-NT association by acting as a noncompetitive inhibitor. On the contrary, Na+ favors the interaction of antagonist, SR48692 by lowering the value of Ki. GTPgamma35S binding to membranes in the presence of 30 mM NaCl suggests that Na+ inhibition of 125I-NT binding is due to the uncoupling of NTR associated G protein(s). In order to explain the entire phenomenon, a two-step, binding model has been proposed. In Step-1, interaction between NT and NTR produces a transient complex, which attains a stable state in the absence of NaCl via step-2, thereby altering the native NTR conformation. The presence of Na+ prevents step-2 by dissociating the transition complex.

Substance P (SP) is a peptide found in the sensory nervous system which has multiple biologic effects including stimulation of muscle contraction, pain nociception, immune cell functions, plasma extravasation and a constellation of inflammatory effects. Here we investigate the role of SP in several animals models of bladder inflammation. Using the female Lewis rat, inflammation was induced using either xylene, lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (polyIC). Inflammation occurred rapidly (4 h) and was maintained in each model for at least 7 days. Each of these protocols decreased the bladder content of immunoreactive SP by approximately 50%, suggesting enhanced release. There was no change in the urinary frequency of these animals over 3 weeks, suggesting that urinary frequency changes are not mediated by acute inflammation. We also found that the SP receptor (NK1) antagonist, (−)CP96345, was unable to block the inflammation produced by polyIC, suggesting that SP is not an obligatory mediator of immune cell stimulation in this model.

To develop an autoimmune animal model for interstitial cystitis (IC), we injected rats with Freund's adjuvant (CFA) containing bladder homogenate (experimentals) or CFA alone (shams). We observed a doubling of urinary frequency in the experimental animals over the shams (P=0.004) and histopathologic changes (venular congestion) consistent with IC. Statistically significant bladder capacity changes were not found. Mast cell (MC) number was not statistically different between experimentals and controls but the number of MCs from section to adjacent section within the same animal's bladder did vary markedly, indicating that MC counts are not a reliable measure of disease in the rat bladder. Splenocytes cultured from the experimental animals and transferred to naive syngeneic recipients were capable of transferring the urinary frequency changes and vascular congestion while splenocytes from animals which did not develop the condition were without effect. In summary, we have developed an autoimmune model for IC consistent with the clinical features of IC. The features of this model can be transferred to naive syngeneic recipients via adoptive splenocyte transfer. The model will permit us to ask and answer important questions about the pathogenesis and treatment of the human disease.