Current and future directions in diagnostic markers in interstitial cystitis

A candidate serum biomarker for bladder pain syndrome/interstitial cystitis

Reliable diagnostic markers for Bladder Pain Syndrome/Interstitial Cystitis (IC) currently are not available. This study evaluated the feasibility of diagnosing IC in humans and domestic cats from the spectra of dried serum films (DSFs) using infrared microspectroscopy. Spectra were obtained from films from 29 humans and 34 domestic cats to create classification models using Soft Independent Modeling by Class Analogy (SIMCA). Ultrafiltration of serum improved discrimination capability. The classification models for both species successfully classified spectra based on condition (healthy/sick), and a different set of masked spectra correctly predicted the condition of 100% of the subjects. Classification required information from the 1500-1800 cm(-1) spectral region to discriminate between subjects with IC, other disorders, and healthy subjects. Analysis of cat samples using liquid chromatography-mass spectroscopy revealed differences in the concentration of tryptophan and its metabolites between healthy and affected cats. These results demonstrate the potential utility of infrared microspectroscopy to diagnose IC in both humans and cats.

Bladder defense molecules, urothelial differentiation, urinary biomarkers, and interstitial cystitis

It has long been recognized that interstitial cystitis (IC) is a disease of the urothelium. In this article, we review the results of published studies and present new data concerning the precise role of the bladder epithelium in IC. We discuss bladder defenses against both the penetration of urinary solutes and bacterial adherence, and we present new information about the proteoglycans that are present on the normal bladder. Previously published results and new data presented here support the conclusion that IC involves an aberrant differentiation program in the bladder urothelium that leads to altered synthesis of several proteoglycans, cell adhesion and tight junction proteins, and bacterial defense molecules such as GP51. These findings lend support to the rationale for glycosaminoglycan replacement therapy for the treatment of patients with IC.

Interleukin-6, histamine, and methylhistamine as diagnostic markers for interstitial cystitis

OBJECTIVES

To examine the specificity and sensitivity of the inflammatory markers histamine, methylhistamine, and interleukin-6 (IL-6) in the urine of patients with interstitial cystitis compared with that in healthy controls.

METHODS

A total of 40 women with interstitial cystitis and 29 healthy controls collected 24-hour urine samples. During the 24 hours before urine collection, all participants refrained from consuming foods and medications that could contain bioactive amines. Methylhistamine and histamine were measured using radioimmunoassay kits and were normalized to urinary creatinine levels; IL-6 was measured using enzyme-linked immunosorbent assay. The data were analyzed by t tests, logistic regression analysis, and receiver operating characteristics.

RESULTS

IL-6 and histamine were significantly greater in the patients with interstitial cystitis than in the controls (P = 0.0003 and P = 0.038, respectively). The methylhistamine levels were also greater in the patients with interstitial cystitis than in the controls, but the results did not reach significance (P = 0.063). Using a combination of IL-6 and methylhistamine/creatinine, cutoff points were established. Using these cutoff points, the sensitivity was 70.0%, specificity 72.4%, positive predictive value 77.8%, and negative predictive value 63.6%.

CONCLUSIONS

All three markers--histamine, methylhistamine, and IL-6--were greater in the patients with interstitial cystitis than in the controls. A combination of methylhistamine and IL-6 could be used as a sensitive and specific marker for interstitial cystitis.

Development of glomerulations in younger women with interstitial cystitis

OBJECTIVES

To evaluate the consistency of cystoscopic findings with hydrodistension in younger women with a clinical diagnosis of interstitial cystitis.

METHODS

A retrospective chart review was conducted of patients aged younger than 26 years old at the time of initial cystoscopy and hydrodistension at a single institution. Data included approximate duration of symptoms, development of visible terminal hematuria, presence of ulcers, and semiquantitive evaluation of degree of glomerulations (negligible, moderate, diffuse), and bladder capacity under anesthesia.

RESULTS

Eighteen women aged 15 to 25 years old (mean, 17.5 years) were identified. The mean duration of symptoms was 38 months, with an estimated mean age of onset of 16 years. No patient had Hunner's ulcers, and 13 had visible terminal hematuria with moderate-to-diffuse glomerulations. Ten women had repeat cystoscopies, and the mean time to repeat cystoscopy was 17 months. Three women underwent repeat cystoscopy and initially had a relatively normal bladder mucosa, with none or only rare glomerulations, but moderate-to-diffuse glomerulations were seen on the subsequent cystoscopy in addition to the development of terminal hematuria. One patient, conversely on subsequent cystoscopy, showed resolution of glomerulations.

CONCLUSIONS

Interstitial cystitis symptoms can develop before an age where adult urologists or primary care physicians familiar with the diagnosis and treatment are usually involved with care. The cystoscopic appearance of the bladder wall after hydrodistension may not be constant over time, and the absence of initial findings of glomerulations or terminal hematuria does not preclude further development of these hallmarks of the disease on subsequent evaluation.

Proteomics approaches to urologic diseases

Biomarkers are greatly needed for several urologic diseases, such as interstitial cystitis, the symptomatic and clinical progression of benign prostate hyperplasia, as well as the specific detection of urologic cancers, including prostate and bladder cancer. This review aims to: briefly describe the need for biomarkers in the field and biomarkers that are currently available for clinicians; address the limitations and roadblocks to effective biomarker discovery; and provide examples and strategies for implementing biomarkers in clinical practice and/or drug discovery.

New theories in interstitial cystitis

Interstitial cystitis (IC) is a chronic symptom-complex characterized by pathological sensation of the bladder (i.e. bladder pain in addition to augmented sensory signals such as urinary frequency and urgency) without evidence of bacterial cystitis or other identifiable lower urinary tract disease. Patients with IC typically describe feeling the urge to void frequently, as well as pain in the bladder and/or urethra. The painful sensation may be described as burning, pressure, sharp, or aching, and is often difficult for the patient to localize precisely. Multiple theories as to the cause of IC have been proposed with varying degrees of evidence. The current body of literature supports the idea that IC is associated with an intrinsic pathology of the bladder urothelial cells. The identification and complete characterization of antiproliferative factor (APF), which is uniquely expressed by urothelial cells in bladders affected by IC, are major advances in the understanding of IC. Additionally, urothelial cells have been likened to neurons because of their ability to express neuronal receptors and release neurotransmitters. The purinergic pathway has been shown to be upregulated in urothelial cells in bladders affected by IC. These new findings should help to direct the development of newer clinical treatments for IC. A complete understanding of IC will only be possible with parallel advances in both basic and clinical sciences.

APF, HB-EGF, and EGF biomarkers in patients with ulcerative vs. non-ulcerative interstitial cystitis

Background

Interstitial cystitis (IC) is a chronic bladder disorder, with symptoms including pelvic and or perineal pain, urinary frequency, and urgency. The etiology of IC is unknown, but sensitive and specific biomarkers have been described, including antiproliferative factor (APF), heparin-binding epidermal growth factor-like growth factor (HB-EGF), and epidermal growth factor (EGF). However, the relative sensitivity of these biomarkers in ulcerative vs. nonulcerative IC is unknown, and these markers have yet to be validated in another laboratory. We therefore measured these markers in urine from patients with or without Hunner's ulcer, as well as normal controls, patients with bladder cancer, and patients with bacterial cystitis, at the First Hospital of China Medical University.

Methods

Urine specimens were collected from two groups of Chinese IC patients (38 IC patients with Hunner's ulcers, 26 IC patients without Hunner's ulcers), 30 normal controls, 10 bacterial cystitis patients and 10 bladder cancer patients. APF activity was determined by measuring ³H-thymidine incorporation in vitro, and HB-EGF and EGF levels were determined by ELISA.

Results

APF activity (inhibition of thymidine incorporation) was significantly greater in all IC patient urine specimens than in normal control specimens or in specimens from patients with bacterial cystitis or bladder cancer (p < 0.0001 for each comparison). Urine HB-EGF levels were also significantly lower and EGF levels significantly higher in both groups of IC patients than in the three control groups (p < 0.0001 for each comparison). Although APF and HB-EGF levels were similar in ulcerative and nonulcerative IC patients, EGF levels were significantly higher in IC patients with vs. without ulcers (p < 0.004).

Conclusion

These findings indicate that APF, HB-EGF and EGF are good biomarkers for both ulcerative and nonulcerative IC and validate their measurement as biomarkers for IC in Chinese patients.

Interstitial cystitis: how should we diagnose it and treat it in 2004?

PURPOSE OF REVIEW

During the last 2 years, two international and two European meetings have taken place and a European Society formed dealing only with interstitial cystitis. A separate committee for interstitial cystitis was formed during the last WHO International Consensus Meeting on urinary incontinence. As a consequence, new concepts and recommendations are evolving, for example the nomenclature is changing from interstitial cystitis to painful bladder syndrome/interstitial cystitis.

RECENT FINDINGS

At an international meeting in Kyoto, the scientific basis for diagnosis and treatment of painful bladder syndrome/interstitial cystitis was reviewed, confirming the poor evidence for many diagnostic procedures and treatments. There are two main reasons for this: an internationally accepted definition is lacking and the disease is rare, making clinical trials difficult. A meeting in Copenhagen resulted in a standardization of the procedures for evaluation and the creation of a European Society for the Study of Interstitial Cystitis. Increased concentration of nitric oxide in the urine of patients with Hunner's ulcer may help to separate ulcer from non-ulcer patients. A prospective, randomized, placebo-controlled multicenter study failed to show a statistically significant effect of the antihistamine hydroxine or pentosan polysulfate sodium compared with placebo. The study confirmed the difficulties in recruiting patients for large-scale trials, which could be one of the reasons for the negative result. The effect of the traditional treatment with amitriptyline was confirmed in a prospective, placebo-controlled study.

SUMMARY

Standardized evaluation of patients with painful bladder syndrome/interstitial cystitis will benefit both patients and science. An internationally accepted definition of the condition appears to be in sight, which will make epidemiological and research studies easier.