Does the menstrual cycle influence cystometry?

Successful induction of stress urinary incontinence in mice by vaginal distension does not depend on the estrous cycle

OBJECTIVE

To determine if the performance of vaginal distension (VD) in different estrous cycle phases affects the successful induction of stress urinary incontinence in mice.

METHODS

Female virgin C57BL/6 mice were distributed into 4 groups according to their estrous cycle phase: proestrus, estrus, metestrus, or diestrus. The estrous cycle was staged by examining vaginal smears, and the method was corroborated by histologic examination of the vagina in a subset of each group. Each group was divided into 4 subgroups for measurement of 24-hour micturition behavior and the leak point pressure (LPP) 4 or 20 days after VD or sham VD.

RESULTS

Voiding events increased and mean void volume decreased 4 days, but not 20 days after VD, and the LPP was decreased 4 days, but not 20 days after VD compared with the corresponding sham group, regardless of the estrous cycle phase when VD was performed. There were no differences in 24-hour micturition behavior or LPP among the 4 different estrous cycle phases either in sham or VD group.

CONCLUSION

Successful induction of reversible stress urinary incontinence in mice is not dependent on the estrous cycle.

[Role of estrogens in lower urinary tract physiology and physiopathology]

GOAL

The aim was to review the literature on estrogens and lower urinary tract.

MATERIAL

A review of literature through the PubMed library until December 31, 2012 was carried out using the following keywords: lower urinary tract, bladder, urethra, nervous central system, innervation, female, women, estrogen, estradiol, urogenital atrophy, urinary incontinence, overactive bladder, urinary tract infection.

RESULTS

On the bladder, estrogens are involved in the trophicity, vascularisation, alpha-adrenergic, cholinergic and muscarinic receptor density, detrusor contractility and inflammation. On the urethra, they impact vascularisation, contractility, urethral pulse and tone, anatomical and functional length. On the neurological control, they act on capsaicin-sensitive afferent fibres, neurological regeneration, nerve growth factor expression and viscerovisceral sensitisation.

CONCLUSION

Estrogens play a major role on the lower urinary tract physiology and physiopathology both on the urethra and the bladder.

Urodynamic and morphometric characteristics of the lower urogenital tracts of female Beagle littermates during the sexually immature period and first and second estrous cycles

OBJECTIVE

To compare values of lower urogenital tract urodynamic and morphometric variables determined during the prepubertal (sexually immature) period and first and second estrous cycles in healthy female Beagle littermates to determine functional and anatomic changes of the lower urogenital tract during those periods.

ANIMALS

5 female Beagle littermates.

PROCEDURES

Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed when dogs were 3.5, 4.5, 5, 6, 7, 8, 8.5, and 9 months old and during proestrus; estrus; early, middle, and late diestrus; and early and late anestrus of the first and second estrous cycles.

RESULTS

At the end of the prepubertal period, values of urodynamic and morphometric variables increased significantly, compared with values at earlier times. Maximum bladder capacity developed when dogs were 9 months old. In all dogs, the bladder was intermittently located in an intrapelvic position during the prepubertal period; the bladder was intra-abdominal from the time dogs were 9 months old until the end of the study. Urethral pressure decreased significantly during estrus and early diestrus of the first and second estrous cycles. Bladder capacity increased significantly during diestrus of both estrous cycles. Urethral and vaginal lengths were significantly longer during proestrus and estrus than they were during anestrus.

CONCLUSIONS AND CLINICAL RELEVANCE

Values of lower urogenital tract urodynamic and morphometric variables were influenced by age and phases of the estrous cycle of immature and young adult Beagles in this study. Age of dog and phase of estrous cycle should be considered when interpreting urodynamic and vaginourethrography data.

Influence of estradiol on micturition thresholds in the rat: involvement of the hypogastric nerve

Studies have shown that the severity of bladder hyperreflexia induced by acute bladder inflammation varies with the ovarian cycle. These results suggest that the hyperreflexia is modulated by ovarian hormones. Other studies have suggested that such modulation involves the bladder's sympathetic innervation. These hypotheses were tested by assessing the development of bladder hyperreflexia in urethane-anesthetized rats subjected to different hormonal manipulations with or without bilateral hypogastric neurectomy (HYPX). The groups included sham ovariectomy (sham OVX), ovariectomy (OVX), OVX with estradiol replacement (OVX+E), OVX+HYPX, and OVX+HYPX+E. Assessments were performed using repeated cystometrograms (CMGs) to measure micturition thresholds (MT) before and hourly for 3 h after intravesicular treatment with 50% turpentine oil (or olive oil in an OVX+E control group). In the uninflamed bladder, treatment with estradiol increased MTs in the OVX+E group compared with the OVX group. As expected, bladder inflammation induced bladder hyperreflexia in sham OVX rats (studied in estrus). This hyperreflexia was eliminated by OVX and restored by either estradiol replacement or HYPX. Combining estradiol replacement and HYPX (i.e., OVX+E+HYPX) did not increase the severity of bladder hyperreflexia compared with either manipulation alone. These results indicate that the bladder hyperreflexia that is induced by bladder inflammation requires the presence of estradiol and suggest that this hormonal modulation is exerted via the sympathetic control of the bladder, possibly via an increase of beta-adrenergic inhibitory actions on the detrusor muscle. Similar mechanisms may contribute to bladder disorders in postmenopausal women.

Estrogen receptor expression in lumbosacral dorsal root ganglion cells innervating the female rat urinary bladder

We have investigated whether bladder afferent neurons are likely to be targets for circulating estrogens by mapping estrogen receptor (ER) distribution in lumbosacral dorsal root ganglia (DRG) of adult female rats. Sensory neurons innervating either the detrusor or trigone regions were identified by application of fluorescent retrograde tracer dyes to the bladder wall. Labelled neurons were classified by their immunoreactivity for either type of ER (ERalpha or ERbeta) and further compared with subpopulations of neurons containing substance P, calcitonin gene-related peptide and vanilloid receptor (a marker of polymodal nociceptors). Both ER types were expressed in numerous sensory neurons of either upper lumbar (L1/L2) or lower lumbar/sacral (L6/S1) ganglia and there was almost complete coexpression of ERalpha and ERbeta. ER-positive neurons were mainly small-medium size (18-25-microm diameter), indicating that they may be nociceptors and/or supply visceral targets. Most bladder-projecting neurons expressed ERs and the majority of these also expressed neuropeptides or vanilloid receptor. Afferent neurons supplying detrusor and trigone regions had similar immunohistochemical features. About a third of the bladder-projecting neurons expressed both ER and vanilloid receptor, suggesting a mechanism by which estrogens could influence bladder pain. The prevalence of different chemical classes of ER-positive bladder-projecting neurons was reflected throughout the entire population of neurons in dorsal root ganglia of these spinal levels, suggesting that neurons supplying other pelvic visceral targets may have similar chemical profiles. These results suggest that many functional classes of sensory neurons innervating the lower urinary tract are likely to be targets for circulating estrogens, including many nociceptor neurons. The coexistence of ERalpha and ERbeta suggests a broad range of potential mechanisms by which estrogens may exert their genomic effects in this system.

Physiology of female micturition

Micturition is a dynamic physiologic process consisting of alternating storage and expulsion phases and is accomplished by complex interactions among innervation, smooth muscle, connective tissue, urothelium and supportive structures. Although our current understanding of the anatomy and physiology of the lower urinary tract is far from complete, intensive research over the last decade has dramatically improved our appreciation of the neural, biomechanical, biochemical, and morphologic properties of the bladder and urethra, as well as the hormonal influences and unique pelvic and perineal anatomy of women. Continued research related to the physiology of female micturition promises to offer new insights into the complex bladder-urethral interactions and to provide a basis for developing better management strategies for a variety of voiding dysfunctions in women.

Does urinary incontinence occurrence depend on the menstrual cycle phase?

BACKGROUND

The aim was to study an eventual co-variation of menstrual cycle progression and urinary incontinence (UI) occurrence in 20-54-year-old-women, who have regular menstrual cycles, which are not influenced by exogenous sex hormones.

METHODS

An age-stratified random sample of of 3900 women, aged 20-59 years, answered a questionnaire on UI. The present analysis included 821 women, who reported regular menstrual cycles un-intervened by sex hormone intake.

RESULTS

Five percent of the women reported episodes of UI the day before they answered the questionnaire. Urinary incontinence was unassociated with menstrual cycle characteristics, such as time position from day one in the menstrual cycle, presence and amount of bleeding and the number of sanitary towels or tampons used. There was however, a borderline significant association (P = 0.08) with day 11-15 before the expected next menstrual bleeding.

CONCLUSIONS

The present data allow for limited co-variation, if any, to exist in UI occurrence with the natural menstrual cycle phases, including the menstruation itself. A hypothesis of a moderate UI increase associated with ovulation however, merits attention.

Estrous influences on micturition thresholds of the female rat before and after bladder inflammation

Recent evidence suggests that lower urinary tract functions may be influenced by reproductive status, particularly under pathophysiological conditions. This study used repeated cystometrograms via a transurethral catheter to investigate the influence of estrous stage on micturition thresholds before and after turpentine-induced bladder inflammation in urethane-anesthetized female rats. Whereas there were no estrous influences on micturition threshold in the uninflamed bladder, micturition thresholds after bladder inflammation were significantly lower in rats in proestrus or estrus than in rats in metestrus or diestrus. Furthermore, the risk that the initial urethral catheterization and preinflammation cystometrogram would produce hematuria was significantly lower in estrus than in the other stages. These estrous influences are not readily explicable by levels of ovarian hormones at the time of testing and may relate instead to dynamic interactions between these hormones and other neuroactive molecules. In addition, the results here have relevance to interpretations of cystometrographic findings in the clinic and basic research.

The impact of the menstrual cycle on urinary symptoms and the results of urodynamic investigation

Four hundred and eighty-three consecutive women referred for videocystourethrography completed a structured questionnaire about their menstrual status and urinary symptoms. Women were included in the study if they were premenopausal, had a regular menstrual cycle and were not taking hormonal therapy. One hundred and thirty-three women satisfied the inclusion criteria of whom 55 (41%) complained that their urinary symptoms were cyclical. The times at which symptoms were said to be at their worst were reported by the women as follows: during a period (n = 20; 36%); just after a period (n = 4; 7%); middle of the month (n = 8; 15%); just before a period (n = 23; 42%). The prevalence of abnormal detrusor activity on videocystourethrography increased significantly with time from the last menstrual period (chi2 for trend = 6.56, P = 0.01) and might reflect increases in the circulating level of progesterone following ovulation. This study provides further indirect evidence that progesterone could have an adverse effect on female lower urinary tract function. In addition, it might be necessary to consider the stage within the menstrual cycle when interpreting the results of urodynamic investigation.

Influence of gender and the oestrous cycle on in vitro contractile responses of the rat urinary bladder to cholinergic stimulation

1. Experiments were done to determine the influence of gender and the oestrous cycle on rat urinary bladder contractility in response to cholinergic stimulation. 2. Bladder strips from female rats responded to high frequency stimulation with smaller contractile responses than did strips from males, and to low concentrations of carbachol with greater responses. The decreased responsiveness of bladder strips from female rats to electrical field stimulation can be primarily attributed to the rats in the oestrous stage of the oestrous cycle. 3. Bladder strips from female rats in all stages of the oestrous cycle were more sensitive to carbachol than those from males, but there were no differences in sensitivity to electrical field stimulation. 4. The contractile responses of strips from both male and female rats to carbachol were antagonized by muscarinic antagonists with the following rank order of affinity (pA(2)) estimates: 4-DAMP>>pirenzepine>methoctramine, suggesting that the receptor mediating contraction was the M3 subtype. There were no differences in pA(2) values between bladder strips from male and female rats. 5. The data indicate that responsiveness of bladder strips to electrical field stimulation and carbachol is altered in female rats in the oestrous stage of the oestrous cycle. Furthermore, gender influences the sensitivity of rat bladder to muscarinic stimulation.