Elevated urinary norepinephrine in interstitial cystitis.

OBJECTIVES: To measure urinary catecholamines and determine the extent to which they may be elevated in urine from patients with interstitial cystitis (IC).
METHODS: Random urine samples from patients with IC (n = 111) and urine from normal volunteers (n = 92) were acidified on collection (voided and catheterized specimens) and assayed for catecholamine (norepinephrine or normetanephrine) by enzyme-linked immunosorbent assay. Creatinine levels in these urine samples were also measured.
RESULTS: Analysis of the data indicated that patients with IC had a higher urinary level of the neurotransmitter norepinephrine compared with the measured levels in the urine of normal volunteers (89.1 +/- 58.3 versus 54.9 +/- 37.1 microg/g creatinine, P <0.05). The metabolite normetanephrine was similar in the urine samples from these two groups. Urine from patients with bladder outlet obstruction (n = 11) did not have elevated amounts of urinary norepinephrine. The norepinephrine levels were not statistically different in the urine samples from patients with symptomatic and asymptomatic IC. The elevated urinary levels in patients with IC did not decrease after treatment with sodium pentosanpolysulfate (Elmiron), heparinoids, dimethyl sulfoxide, or combinations of these during 1 to 15 months of treatment.
CONCLUSIONS: Norepinephrine was found to be elevated in the urine from patients with IC compared with urine from normal controls. This would be consistent with increased sympathetic (adrenergic) activity from the bladders of patients with IC or possibly from increased adrenal activity, since stress is associated with symptom increase in some patients with IC. Norepinephrine levels did not decrease with treatment nor did they differ between symptomatic and asymptomatic patients at the time of urine collection.