Antiproliferative factor signaling and interstitial cystitis/painful bladder syndrome

Biomarkers in Interstitial Cystitis/Bladder Pain Syndrome with and without Hunner Lesion: A Review and Future Perspectives

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating urinary bladder condition that presents with a wide variety of clinical phenotypes. It is commonly characterized by persistent pelvic pain and lower urinary tract symptoms, such as urinary frequency and urgency. Current clinicopathological and genomic evidence has indicated that IC/BPS with Hunner lesions is a clinically relevant distinct subtype with proven bladder pathology of subepithelial chronic inflammatory changes that are characterized by enhanced local immune responses and epithelial denudation. However, other forms of IC/BPS lacking Hunner lesions are a symptom syndrome complex of non-inflammatory conditions with little evidence of bladder etiology, characterized by aberrant neural activity in neurotransmission systems which leads to central nervous sensitization with potential involvement of urothelial malfunction, or clinical presentation of somatic and/or psychological symptoms beyond the bladder. Given such distinct potential pathophysiology between IC/BPS subtypes, disease biomarkers of IC/BPS should be provided separately for subtypes with and without Hunner lesions. Tailored approaches that target characteristic immunological inflammatory processes and epithelial denudation for IC/BPS with Hunner lesions, or the sensitized/altered nervous system, urothelial malfunction, association with other functional somatic syndromes, and psychosocial problems for IC/BPS without Hunner lesions, are essential to identify optimal and reliable disease-specific IC/BPS biomarkers.

Bladder Pain Syndrome and Interstitial Cystitis Beyond Horizon: Reports from the Global Interstitial Cystitis/Bladder Pain Society (GIBS) Meeting 2019 Mumbai - India

Purpose of the Meeting

Bladder pain syndrome/interstitial cystitis is a prevalent but underserved disease. At the Global Interstitial Cystitis/Bladder Pain Syndrome Society (GIBS) meeting, the organization and participants were committed to delivering word-class expertise and collaboration in research and patient care. Under the umbrella of GIBS, leading research scholars from different backgrounds and specialties, as well as clinicians, from across the globe interested in the science and art of practice of Bladder Pain Syndrome (BPS)/Interstitial Cystitis (IC) were invited to deliberate on various dimensions of this disease. The meeting aimed to have global guidelines to establish firm directions to practicing clinicians and patients alike on the diagnosis and treatment of this disease entity. Chronic Pelvic Pain Syndrome (CPPS) is defined by pain in the pelvic area that can have different etiologies. This can be due to urologic, gynecologic, musculoskeletal, gastrointestinal, neurologic, and autoimmune or rheumatologic diseases. At the GIBS meeting held in Mumbai, India, in August 2019, a multidisciplinary expert panel of international urologists, gynecologists, pain specialists, and dietitians took part in a think tank to discuss the development of evidence-based diagnostic and treatment algorithms for BPS/IC.

Summary of Presented Findings

The diagnosis of BPS/IC is difficult in daily clinical practice. Patients with BPS/IC present with a variety of signs and symptoms and clinical test results. Hence, they might be misdiagnosed or underdiagnosed, and the correct diagnosis might take a long time. A good history and physical examination, along with cystoscopy, is a must for the diagnosis of IC/BPS. For the treatment, besides lifestyle management and dietary advice, oral medication and bladder instillation therapy, botulinum toxin, and sacral neuromodulation were discussed. The innovation in bladder instillation applicators, as well as battery-free neuromodulation through the tibial nerve, was discussed, as well.

Recommendation for Future Research

As BPS/IC is complex, for many patients, several treatments are necessary at the same time. This was presented at GIBS 2019 as the piano model. In this way, a combination of treatments is tailored to an individual patient depending on the symptoms, age, and patients' characteristics. In the art of medicine, especially when dealing with BPS/IC patients, pressing the right key at the right time makes the difference.

How many lives does CLIMP-63 have?

In 1995, in the Biochemical Society Transactions, Mundy published the first review on CLIMP-63 (cytoskeleton-linking membrane protein 63) or CKPA4 (cytoskeleton-associated protein 4), initially just p63 [1]. Here we review the following 20 years of research on this still mysterious protein. CLIMP-63 is a type II transmembrane protein, the cytosolic domain of which has the capacity to bind microtubules whereas the luminal domain can form homo-oligomeric complexes, not only with neighbouring molecules but also, in trans, with CLIMP-63 molecules on the other side of the endoplasmic reticulum (ER) lumen, thus promoting the formation of ER sheets. CLIMP-63 however also appears to have a life at the cell surface where it acts as a ligand-activated receptor. The still rudimentary information of how CLIMP-63 fulfills these different roles, what these are exactly and how post-translational modifications control them, will be discussed.

Metabolomics insights into pathophysiological mechanisms of interstitial cystitis

Interstitial cystitis (IC), also known as painful bladder syndrome or bladder pain syndrome, is a chronic lower urinary tract syndrome characterized by pelvic pain, urinary urgency, and increased urinary frequency in the absence of bacterial infection or identifiable clinicopathology. IC can lead to long-term adverse effects on the patient's quality of life. Therefore, early diagnosis and better understanding of the mechanisms underlying IC are needed. Metabolomic studies of biofluids have become a powerful method for assessing disease mechanisms and biomarker discovery, which potentially address these important clinical needs. However, limited intensive metabolic profiles have been elucidated in IC. The article is a short review on metabolomic analyses that provide a unique fingerprint of IC with a focus on its use in determining a potential diagnostic biomarker associated with symptoms, a response predictor of therapy, and a prognostic marker.

Squamous cell carcinoma of the bladder mimicking interstitial cystitis and voiding dysfunction

Squamous cell carcinoma (SCC) of the bladder is a relatively uncommon cause of bladder cancer accounting for <5% of bladder tumors in the western countries. SCC has a slight male predominance and tends to occur in the seventh decade of life. The main presenting symptom of SCC is hematuria, and development of this tumor in the western world is associated most closely with chronic indwelling catheters and spinal cord injuries. A 39-year-old Caucasian female presented with bladder and lower abdominal pain, urinary frequency, and nocturia which was originally believed to be interstitial cystitis (IC) but was later diagnosed as SCC of the bladder. Presentation of SCC without hematuria is an uncommon presentation, but the absence of this symptom should not lead a practitioner to exclude the diagnosis of SCC. This case is being reported in an attempt to explain the delay and difficulty of diagnosis. Background on the risk factors for SCC of the bladder and the typical presenting symptoms of bladder SCC and IC are also reviewed.

'Omics' approaches to understanding interstitial cystitis/painful bladder syndrome/bladder pain syndrome

Recent efforts in the generation of large genomics, transcriptomics, proteomics, metabolomics and other types of 'omics' data sets have provided an unprecedentedly detailed view of certain diseases, however to date most of this literature has been focused on malignancy and other lethal pathological conditions. Very little intensive work on global profiles has been performed to understand the molecular mechanism of interstitial cystitis/painful bladder syndrome/bladder pain syndrome (IC/PBS/BPS), a chronic lower urinary tract disorder characterized by pelvic pain, urinary urgency and frequency, which can lead to long lasting adverse effects on quality of life. A lack of understanding of molecular mechanism has been a challenge and dilemma for diagnosis and treatment, and has also led to a delay in basic and translational research focused on biomarker and drug discovery, clinical therapy, and preventive strategies against IC/PBS/BPS. This review describes the current state of 'omics' studies and available data sets relevant to IC/PBS/BPS, and presents opportunities for new research directed at understanding the pathogenesis of this complex condition.