What is in the pipeline for new treatments for bladder pain syndrome/ interstitial cystitis?

PURPOSE OF REVIEW

Despite available treatments, many bladder pain syndrome/interstitial cystitis (BPS/IC) patients continue to have poor quality of life. Thus, there is an urge for new therapies. Our manuscript aims to review papers about BPS/IC treatments published in the last 2 years.

RECENT FINDINGS

During this period, several treatments were tested, most of them new and others combining treatments already used. Pentosan polysulfate, interleukin 1 antagonist, low energy shock wave, physical therapy, hypnosis, acupuncture, clorpactin, dimethyl sulfoxide and hyaluronic acid plus botulinum toxin-A showed positive results. ASP3652 and lidocaine-releasing intravesical systems failed to prove their efficacy.

SUMMARY

Validation of these studies is arduous due to the broad spectre of BPS/IC phenotypes, small number of patients enrolled, distinct outcome measures and short-term follow-up. It is also important to highlight that some authors combined therapies, and others split central and peripheric phenotypes before treatment. Therefore, soon, phenotyping and combining therapies with a step-by-step approach will be needed in BPS/IC treatment.

Clinical profiling of specific diagnostic subgroups of women with chronic pelvic pain

Introduction

Chronic pelvic pain (CPP) is a common condition affecting up to 26.6% of women, with many suffering for several years before diagnosis and/or treatment. Its clinical presentation is varied and there are frequently comorbid conditions both within and outside the pelvis. We aim to explore whether specific subgroups of women with CPP report different clinical symptoms and differing impact of pain on their quality of life (QoL).

Methods

The study is part of the Translational Research in Pelvic Pain (TRiPP) project which is a cross-sectional observational cohort study. The study includes 769 female participants of reproductive age who completed an extensive set of questions derived from standardised WERF EPHect questionnaires. Within this population we defined a control group (reporting no pelvic pain, no bladder pain syndrome, and no endometriosis diagnosis, N = 230) and four pain groups: endometriosis-associated pain (EAP, N = 237), interstitial cystitis/bladder pain syndrome (BPS, N = 72), comorbid endometriosis-associated pain and BPS (EABP, N = 120), and pelvic pain only (PP, N = 127).

Results

Clinical profiles of women with CPP (13-50 years old) show variability of clinical symptoms. The EAP and EABP groups scored higher than the PP group (p < 0.001) on the pain intensity scales for non-cyclical pelvic pain and higher than both the BPS and PP groups (p < 0.001) on the dysmenorrhoea scale. The EABP group also had significantly higher scores for dyspareunia (p < 0.001), even though more than 50% of sexually active participants in each pain group reported interrupting and/or avoiding sexual intercourse due to pain in the last 12 months. Scores for the QoL questionnaire (SF-36) reveal that CPP patients had significantly lower QoL across all SF-36 subscales (p < 0.001). Significant effects were also observed between the pain groups for pain interference with their work (p < 0.001) and daily lives (p < 0.001), with the EABP suffering more compared to the EAP and PP groups (p < 0.001).

Discussion

Our results demonstrate the negative impact that chronic pain has on CPP patients' QoL and reveal an increased negative impact of pain on the comorbid EABP group. Furthermore, it demonstrates the importance of dyspareunia in women with CPP. Overall, our results demonstrate the need for further exploration of interventions targeting QoL more broadly and suggest that novel approaches to classifying women with CPP are needed.

Daily low dose of tadalafil improves pain and frequency in bladder pain syndrome/interstitial cystitis patients

Objective: Bladder pain syndrome/interstitial cystitis (BPS/IC) is a chronic disease, with consequent high morbidity. Increasing evidence suggests that bladder afferent hyperexcitability, through neurogenic bladder inflammation and urothelial dysfunction, plays a key role in the pathophysiology of BPS/IC. The rationale of using phosphodiesterase type 5 inhibitors (PDE5i) would be to decrease bladder afferent hyperactivity. Detrusor relaxation, improvement of microcirculation, and a decrease in adrenergic nociceptive overactivity would be other effects in bladder tissue. We aimed to evaluate the efficacy, tolerability, and safety of a daily low dose of 5 mg tadalafil in refractory BPS/IC patients.

Material and methods: A total of 14 refractory BPS/IC female patients, previously evaluated with a physical examination, bladder diary, bladder-pain related visual analogue score, O’Leary-Sant Scores (OSS) for symptoms and problems, and quality of life (QoL) question from International Prostate Symptom Score, were treated with 5 mg of tadalafil, for 3 months. Re-evaluations occurred at 4 and 12 weeks. Adverse events were assessed and recorded.

Results: Urinary frequency, OSS, and QoL were significantly improved at 1-month follow-up (10 ± 2.5, 21.9 ± 4.1, and 4 ± 1.5, respectively, P < .05). Pain intensity and volume voided were significantly improved at a 3-month follow-up (3.5 ± 2 and 266.7 ± 60.5, P < .05). Patients referred to urinary frequency as the most important parameter improved at 4 weeks, and pain at 3 months. No differences between ulcerated and nonulcerated patients were observed. Two patients dropped out due to unsatisfactory results and two due to persistent headache and/or tachycardia, but both events were resolved after discontinuing the drug.

Conclusion: Daily low-dose tadalafil is an easy, well-tolerated, and effective treatment for refractory BPS/IC in women.

Molecular characterization of a new arcelin-5 gene

Arcelins are insecticidal proteins found in some wild accessions of the common bean, Phaseolus vulgaris. They are grouped in six allelic variants and arcelin-5 is the variant with the highest inhibitory effect on the development of Zabrotes subfasciatus larvae. Characterization of the protein and its genes resulted in the identification of three polypeptides and the isolation of two genes that encode the Arc5a and Arc5b polypeptides. Here we describe a new gene, Arc5-III. The protein it encodes has 81% amino acid identity with the derived amino acid sequences of Arc5-I and Arc5-II. The Arc5-III gene is highly expressed in developing seeds and at a much lower level in roots. Data obtained by a combination of two-dimensional gel electrophoresis, protein sequencing and MALDI-TOF mass spectrometry analysis support the conclusion that Arc5-III encodes a polypeptide present in Arc5c band. Using ion-exchange chromatography, three fractions containing arcelin-5 polypeptides were eluted by increasing the salt concentration. The three fractions contain various amounts of the three arc-5 polypeptides and inhibit the growth of Zabrotes subfasciatus larvae differentially, suggesting differences in insecticidal activity among the arcelin-5 isoforms.