INCREASED URINARY HYALURONIC ACID AND INTERSTITIAL CYSTITIS:

The potassium sensitivity test: a predictor of treatment response in interstitial cystitis

OBJECTIVE

To determine whether the potassium sensitivity test (PST) can be used to predict the response to treatment with intravesical sodium hyaluronate in patients with interstitial cystitis.

PATIENTS AND METHODS

Thirty-eight patients diagnosed with interstitial cystitis were recruited; each had a PST, carried out in a double-blind fashion, followed by six weekly doses of intravesical sodium hyaluronate. The patients were assessed before and after treatment using a self-administered interstitial cystitis symptom index (CSI) and problem index (PI). The clinical response was defined as none (<25% improvement in clinical symptoms), mild (>25%), moderate (50-75%) and excellent (>75%).

RESULTS

The PST was positive in 23 and negative or indeterminate in 13 patients; two patients withdrew from the study. Overall 20 of 36 (55%) patients reported an improvement after six doses of intravesical sodium hyaluronate, but 17 (74%) with a positive PST improved, compared to only five (22%) with a negative test (P = 0.03). There was an improvement in the CSI after treatment in both groups, but a significant improvement in the PI only in patients with a positive PST (P = 0.01). The magnitude of change for the CSI and PI was significantly greater in the positive than in the negative group (CSI, P = 0.043; PI, P < 0.001). There were no major complications. Three patients complained of pain after the test, and two with a positive and one with a negative PST developed a urinary tract infection.

CONCLUSIONS

Although the role of the PST in the diagnosis of interstitial cystitis requires further clarification, the test helps to predict the response to treatment with glycosaminoglycan-substitution therapy.

Isolation, identification, and quantitation of urinary glycosaminoglycans

BACKGROUND

Substantial amounts of glycosaminoglycans (GAGs) are present in the urine of healthy individuals, but the concentration in the serum is very low. This finding suggests that urinary GAGs come from the glomerulus and may reflect the turnover of GAGs in the glomerulus.

HYPOTHESIS

However, little is known about the physiologic regulation of the urinary GAGs in humans, and so investigations are needed to evaluate the effects of age and sex on urinary GAGs in normal individuals.

METHODS

Eighty-seven healthy subjects were included in this study. Urinary GAGs were isolated and quantified at the nanogram level by combined azure A-silver staining in agarose gels.

RESULTS

The level of urinary GAGs peaked at 10-19 years in both sexes. The proportion of chondroitin sulfate decreased with age, but the proportion of heparan sulfate increased with age.

CONCLUSION

The total amount of GAGs and the proportions of chondroitin sulfate, heparan sulfate, and dermatan sulfate appear to change with age. Therefore, investigations in which urinary GAG is used as a parameter of glomerular GAG turnover should ensure that control groups are precisely matched for age. Changes in the proportions of each GAG may be more informative than their absolute levels.