Effects of vitamin D analog on bladder function and sensory signaling in animal models of cystitis

The effect of vitamin D deficiency and supplementation on urinary incontinence: scoping review

INTRODUCTION AND HYPOTHESIS

Vitamin D receptors are found in skeletal and smooth muscle cells throughout the body, specifically in the bladder detrusor muscle. We reviewed the current literature on the association between vitamin D deficiency and urinary incontinence (UI), and whether vitamin D supplementation plays a role in the treatment of UI symptoms.

METHODS

We performed a scoping review of all available studies. PubMed, Google Scholar, and PEDro databases were searched from inception until August 2020 with the keywords "urinary incontinence," "pelvic floor disorders," "lower urinary tract symptoms," "overactive bladder," and various terms for vitamin D. No language restrictions were imposed. The reference lists of all retrieved articles were also searched.

RESULTS

The search revealed 12 studies of different research methodologies after elimination. In 6 out of the 7 cross-sectional studies reviewed, a significant association between vitamin D deficiency or insufficiency and the onset and severity of UI was found. In 2 out of the 3 prospective studies included, no association between vitamin D intake and UI was found; however, both randomized controlled trials that were reviewed found that vitamin D supplementation is effective for the treatment of UI.

CONCLUSIONS

The existing literature supports an association between low levels of serum vitamin D and UI. Initial evidence regarding the effect of vitamin D supplementation on UI is accumulating, yet additional, comprehensive research is warranted to establish these findings.

Do we need to know more about the effects of hormones on lower urinary tract dysfunction? ICI-RS 2014

This review article reflects the presentations and subsequent discussions during a think tank at the 5th International Consultation on Incontinence Research Society's annual meeting, held in Bristol, UK (September 22-24, 2014). It reviews the current state of knowledge on the role of hormones in lower urinary tract dysfunction (LUTD) and overactive bladder (OAB) and in particular: highlights some specific basic research findings from discussion participants; reviews future research topics; and discusses potential new therapeutic opportunities for LUTD and OAB. The role of the large conductance voltage- and Ca(2+) -activated K(+) (BK) channels, as novel therapeutic targets for OAB was discussed, in particular as recent studies on human detrusor smooth muscle suggest that estradiol exerts a direct non-genomic activation of the BK channels. Recent developments on the roles of sex hormones on diuresis, as well as the roles of melatonin and vitamin D on LUTD were also discussed. It was concluded that further basic science and translational studies are needed to better understand hormonal regulatory mechanisms of the lower urinary tract and the implications for novel treatment options for LUTD and OAB.

The Influence of Maxacalcitol, Vitamin D3 Analog, on Detrusor Overactivity in Conscious Rats

OBJECTIVES

To test the hypothesis that maxacalcitol, vitamin D3 analog, would ameliorate detrusor overactivity (DO) induced by retinyl acetate instillation; to test the outcome of the combined administration of maxacalcitol and the rho kinase inhibitor - GSK 269962, amlodipine besylate, or oxybutynin chloride in this model.

METHODS

The rats were treated with maxacalcitol for 14 days. Then, cystometric studies were performed during which the animals were administered test compounds.

RESULTS

Maxacalcitol in a dose of 30 but not 15 µg/kg/day induced reduction in DO index, non-voiding contractions frequency (FNVC), and amplitude (ANVC), while increasing volume threshold to elicit non-voiding contractions (VTNVC). The 14-day-long administration of maxacalcitol at a dose of 15 µg/kg/day to animals, followed by GSK 269962 at a single dose of 10 mg/kg, led to a statistically significant reduction of intercontraction interval and bladder compliance, and an increase in DO index, without any effect on ANVC, FNVC, and VTNVC. The assessment of the combined effect of maxacalcitol (15 µg/kg/day) and amlodipine besylate (0.25 mg/kg) demonstrated an increase in intercontraction interval, bladder compliance and VTNVC, with a decrease in FNVC. No statistically significant changes were found in DO index and ANVC. The combined outcome of administering maxacalcitol (15 µg/kg/day) and oxybutynin chloride (0.25 mg/kg) did not show any statistically significant value of the measured cystometric parameters.

CONCLUSION

The outcomes of maxacalcitol administration can be the result of 3 mechanisms, that is, the upregulation of L-type Ca(2+) channels, the inhibition of the rho kinase pathway, and a so far unknown central mechanism.

Pioneering drugs for overactive bladder and detrusor overactivity: Ongoing research and future directions

The ongoing research on pioneering drug candidates for the overactive bladder (OAB) aimed to overcome the limitations of currently licensed pharmacotherapies, such as antimuscarinics, β3-adrenergic agents, and botulinum neurotoxin, has been reviewed performing a systematic literature review and web search. The review covers the exploratory agents alternative to available medications for OAB and that may ultimately prove to be therapeutically useful in the future management of OAB patients based on preclinical and early clinical data. It emerges that many alternative pharmacological strategies have been discovered or are under investigation in disease-oriented studies. Several potential therapeutics are known for years but still find obstacles to pass the clinical stages of development, while other completely novel compounds, targeting new pharmacological targets, have been recently discovered and show potential to translate into clinical therapeutic agents for idiopathic and neurogenic OAB syndrome. The global scenario of investigational drugs for OAB gives promise for the development of innovative therapeutics that may ultimately prove effective as first, combined or second-line treatments within a realistic timescale of ten years.

Innovative pharmacotherapies for women with overactive bladder: where are we now and what is in the pipeline?

INTRODUCTION AND HYPOTHESIS

The impressive prevalence of overactive bladder (OAB) and the relevant limitations of current treatments urge the need for novel therapeutic approaches.

METHODS

A systematic literature and web search was performed to identify investigational drugs that entered the early and late phases of clinical development for women with OAB symptoms.

RESULTS

Approved pharmacological therapies for OAB (antimuscarinics, beta-3 agonists, and botulinum toxin) are evolving with the development of alternative administration methods, combination strategies, and novel compounds, expected to improve effectiveness, bladder selectivity, and dose flexibility. A wealth of investigational compounds, developed with both public and companies' indoor nonclinical disease-oriented studies, entered the early and late stages of clinical development in the last decade. Most non-anticholinergic compounds in ongoing clinical trials target central and peripheral neurotransmitter receptors involved in neurological modulation of micturition, nonadrenergic-noncholinergic mechanisms, cyclic nucleotide metabolism, different subtypes of ion channels or peripheral receptors of prostaglandins, vanilloids, vitamin D3, and opioids. Fascinating advances are ongoing also in the field of genetic therapy.

CONCLUSIONS

New pharmaceutical formulations and drug combinations are expected to be available in the next decade in order to overcome the limitations of current drugs for OAB. Although proof-of-concept, patient-oriented studies yielded disappointing results for several tentative drugs, a lot of clinical research is ongoing that is expected to provide clinicians with novel therapeutic agents in the near future.