Estrogen and progesterone receptors in the uterosacral ligament

Estrogen and Androgen Receptor Status in Uterosacral Ligaments of Women with Pelvic Organ Prolapse Stratified by the Pelvic Organ Prolapse Histology Quantification System

Menopause is a significant risk factor for pelvic organ prolapse (POP), suggesting that ovarian sex steroids play a major role in the etiology of the condition. POP results from failure of the uterine-cervix-vagina support structures, including the uterosacral ligament (USL). We previously identified consistent degenerative USL phenotypes that occur in POP and used their characteristics to develop a standardized POP Histologic Quantification System (POP-HQ). In this study, POP and matched control USL tissue was first segregated into the unique POP-HQ phenotypes, and specimens were then compared for estrogen receptor (ER) alpha (ERα), ERbeta (ERβ), the G-protein estrogen receptor (GPER), and androgen receptor (AR) content via immunohistochemical staining. ER and AR expression levels in the control USL tissues were indistinguishable from those observed in the POP-A phenotype, and partially overlapped with those of the POP-I phenotype. However, control-USL steroid receptor expression was statistically distinct from the POP-V phenotype. This difference was driven mainly by the increased expression of GPER and AR in smooth muscle, connective tissue, and endothelial cells, and increased expression of ERα in connective tissue. These findings support a multifactorial etiology for POP involving steroid signaling that contributes to altered smooth muscle, vasculature, and connective tissue content in the USL. Furthermore, these data support the concept that there are consistent and distinct degenerative processes that lead to POP and suggest that personalized approaches are needed that target specific cell and tissues in the pelvic floor to treat or prevent this complex condition.

Expression of Estrogen Receptor Alpha and Evaluation of Histological Degeneration Scores in Fibroblasts of Hypertrophied Ligamentum Flavum: A Qualitative Study

The most common spinal disorder in elderly is lumbar spinal stenosis (LSS), resulting partly from ligamentum flavum (LF) hypertrophy. Its pathophysiology is not completely understood. The present study wants to elucidate the role of estrogen receptor α (ER α) in fibroblasts of hypertrophied LF. LF samples of 38 patients with LSS were obtained during spinal decompression. Twelve LF samples from patients with disk herniation served as controls. Hematoxylin & Eosin (H&E) and Elastica stains and immunohistochemistry for ER α were performed. The proportions of fibrosis, loss and/or degeneration of elastic fibers and proliferation of collagen fibers were assessed according to the scores of Sairyo and Okuda. Group differences in the ER α and Sairyo and Okuda scores between patients and controls, male and female sex and absence and presence of additional orthopedic diagnoses were assessed with the Mann–Whitney U test. There was a tendency towards higher expression of ER α in LF fibroblasts in the hypertrophy group (p = 0.065). The Sairyo and Okuda scores were more severe for the hypertrophy group but, in general, not statistically relevant. There was no statistically relevant correlation between the expression of ER α and sex (p = 0.326). ER α expression was higher in patients with osteochondrosis but not statistically significant (p = 0.113). In patients with scoliosis, ER α expression was significantly lower (p = 0.044). LF hypertrophy may be accompanied by a higher expression of ER α in fibroblasts. No difference in ER α expression was observed regarding sex. Further studies are needed to clarify the biological and clinical significance of these findings.

Age and/or postmenopausal status as risk factors for pelvic organ prolapse development: systematic review with meta-analysis

INTRODUCTION AND HYPOTHESIS

Age is named as a risk factor for pelvic organ prolapse (POP), despite not being the primary outcome for many observational studies. Postmenopausal status is another associated factor but has many confounders. We aimed to systematically review the role of age and/or postmenopausal status in POP development.

METHODS

Systematic review addressing age and hormones, more specifically by postmenopausal status, from inception to March 2020 in four databases (PubMed, Embase, WOS, Cochrane Library). Quality of evidence was classified by the ROBINS-I classification for non-randomized studies. Experimental studies, animal studies, studies linking age with recurrent POP and case series were excluded. Effect estimates were collected from adjusted odds ratio plus 95% confidence intervals. Significance level was 5%. A discussion exploring mechanistic factors was also included.

RESULTS

Nineteen studies (11 cross sectional, 6 cohort and 2 case control) were included for quantitative analysis. Only two studies presented a low overall risk of bias for age; most of the domains were of moderate risk. Every additional year was responsible for a 10% increase in the risk to develop POP (OR = 1.102 [1.021-1.190]; i² = 80%, random analysis, p = 0.012). This trend was confirmed when age was dichotomized into a cutoff of 35 (p = 0.035) and 50 (p < 0.001) years. Although an increase in the risk for POP was noted in postmenopausal women, this did not reach statistical significance (OR = 2.080 [0.927-4.668], i² = 0%, p = 0.076).

CONCLUSION

Age is a risk factor for POP; postmenopausal status was not statistically associated with POP, prompting the need for further studies addressing this factor.

Effects of short-term moderate ZEN consumption on uterosacral ligament elasticity in pubertal gilts

Zearalenone (ZEN) is a potent estrogenic toxin in swine, contributing to economic losses in herds via reproductive consequences such as pelvic organ prolapse (POP). To better understand the relationship between ZEN-consumption and reproductive symptoms, an animal feeding study with pubertal gilts was designed. The gilts were exposed to three different treatments: solvent-only feed for 21 days (n = 10), ZEN-spiked feed for 7 days followed by solvent-only feed for 14 days (n = 10), and ZEN-spiked feed for 21 days (n = 10). The gilts did not display any ZEN-related symptoms throughout any of the treatments. At the end of the trial the elastic properties of the USLs from participating gilts were evaluated along two loading directions: main direction (MD) and perpendicular direction (PD). The elastic properties included average stresses at 2% and 4% strains, and secant moduli. Overall the elastic properties of the USLs did not vary across treatment groups or between loading directions. In the MD, average stress increased from 32.96 ± 4.43 kPa at 2% strain to 63.21 ± 9.69 kPa at 4% strain, with a secant modulus of 1.52 ± 0.27 MPa. In the PD, average stress increased from 40.82 ± 4.22 kPa at 2% strain to 83.38 ± 9.17 kPa at 4% strain, with a secant modulus of 2.13 ± 0.31 MPa. Continued research into the relationship between ZEN consumption and reproductive symptoms such as POP is necessary in order to mitigate their deleterious effects in herds.

Effect of estradiol on fibroblasts from postmenopausal idiopathic carpal tunnel syndrome patients

Fibrosis of the subsynovial connective tissue (SSCT) is a characteristic finding in patients with idiopathic carpal tunnel syndrome (CTS). Idiopathic CTS frequently occurs in postmenopausal women; therefore, female steroid hormones, especially estrogens, may be involved in its development. In this study, we evaluated the effect of the estradiol on the expression of genes and proteins related to fibrosis of SSCT fibroblasts from patients with idiopathic CTS. This study included 10 postmenopausal women (mean age 76 years). Fibroblasts derived from SSCT were treated with estradiol (10^-4 -10^-12  M), and the expression levels of TGF-β-responsive genes were evaluated. The relationships between the expression of untreated estrogen receptor α (ERα) and ERβ and changes in gene expression due to estradiol treatment were examined by quantitative real-time polymerase chain reaction. The effects of 10^-4  M estradiol on collagen type I (Col1) and collagen type III (Col3) protein expression levels were also evaluated by fluorescent staining. The relationships between ERα/β and Col1/3 expression were evaluated by immunohistochemical staining. The reduction in Col1A1 mRNA expression due to estradiol treatment was positively correlated with ERα expression (r = 0.903, p < 0.01). At the protein level, expression of Col1 and Col3 were down-regulated. These results indicated that ERα-mediated signaling may be involved in the regulation of Col1A1, and its regulatory effect may be dependent on the ERα expression level. The accurate evaluation of ERα expression level in the SSCT of individual patients with idiopathic CTS might guide the effective use of new estrogen replacement therapy.

Pelvic organ prolapse and endogenous circulating sex steroids in postmenopausal women: A case control-study

OBJECTIVE

We compared sex steroid levels of postmenopausal patients with symptomatic pelvic organ prolapse (POP) with postmenopausal matched patients without any sign of POP. Furthermore, we evaluated a possible relationship between sex steroid levels and various urogynecologic parameters in cases with POP. Main outcome of interest were differences in circulating estradiol levels between the two groups.

STUDY DESIGN

We conducted a case-control study and 46 postmenopausal women with symptomatic POP≥stage 2 were matched 1:1 with 46 urogynecologic healthy women. Blood samples were drawn from all patients for assessment for estradiol (E2), Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), testosterone (T), androstendion (AEON), dehydroepiandrosterone sulphate (DHEAS) and sex hormone binding globulin (SHBG) with an Electrochemiluminescence immunoassay.

RESULTS

Our study failed to show any statistically significant differences in sex steroid levels between women with and without POP (p>0.05). However, serum concentration of E2 (p<0,0001), free testosterone (p=0,034) and DHEAS (p=0,024) was statistically significant lower in patients with severe prolapse stage. Serum levels of E2 were statistically significant higher in cases with moderate-strong Oxford Grading Scale (p<0,0001). Low circulating E2 (p=0,019) as well as menopausal age (p=0,022) remained independent risk factors for POP in multiple logistic regression analysis.

CONCLUSION

The significant low hormonal levels in cases with high POP-Q stage as well as the significant higher estradiol levels in patients with strong Oxford Grading Scale may indicate that endogenous circulating sex steroids might have a potential role in the severity and progression of POP.

Matrix Metalloproteinase-1 Expression in Women With and Without Pelvic Organ Prolapse: A Systematic Review and Meta-analysis

This meta‐analysis was conducted to estimate the association between matrix metalloproteinase‐1 (MMP‐1) expression and pelvic organ prolapse (POP) in women. Relevant studies published before 6 December 2015 were identified by searching PubMed, Ovid, EBSCO, and EMBASE. A total number of five case–control studies, including 182 POP cases and 192 controls, were identified. The results indicated that women without POP had a lower MMP‐1 level of expression compared with women with POP (odds ratio = 0.54, 95% confidence interval: 0.43–0.67, P = 0.000). After stratification by biopsy site, ethnicity, or menopausal status, this finding was also confirmed in the subgroup analysis with no significant changes. Egger's linear regression test revealed a potential publication bias (P = 0.028). The findings of our study indicate that women who suffer from POP have a higher expression level of MMP‐1 than women without POP.

Increased lubricin/proteoglycan 4 gene expression and decreased modulus in medial collateral ligaments following ovariohysterectomy in the adult rabbit: Evidence consistent with aging

This study investigated whether ovariohysterectomy (OVH) surgery to induce menopause resulted in changes to modulus, failure strain and lubricin/proteoglycan 4 (PRG4) gene expression in rabbit medial collateral ligaments (MCLs), similar to aging (Thornton et al., 2015a). The MCLs from adult rabbits that underwent OVH surgery as adolescents (15-week-old) and adults (1-year-old) were compared by evaluating mechanical behaviour (adolescent OVH, n=8; adult OVH, n=7; normal, n=7), gene expression (adolescent OVH, n=9; adult OVH, n=8; normal, n=8), and collagen and glycosaminoglycan (adolescent OVH, n=9; adult OVH, n=8; normal, n=8) and water (adolescent OVH, n=9; adult OVH, n=8; normal, n=8) content. Mechanical behaviour evaluated cyclic, static and total creep strain, and ultimate tensile strength, modulus and failure strain. The RT-qPCR assessed mRNA levels for matrix regulatory genes. Adult OVH MCLs exhibited increased cyclic creep and failure strain, and decreased modulus with increased mRNA levels for lubricin/PRG4 and collagen I compared with normal MCLs. Adolescent OVH MCLs exhibited increased cyclic, static and total creep strain with decreased mRNA levels for the progesterone receptor. Lubricin/PRG4 plays a role in the lubrication of collagen fascicles which is likely related to the decreased modulus and increased failure strain observed in ligaments from adult OVH rabbits. Progesterone and its receptor are thought to play a role in the stretching of ligaments in pelvic organ prolapse and pregnancy which is likely related to the increase in creep strain observed in ligaments from adolescent OVH rabbits. Ovariohysterectomy in adult rabbits resulted in changes that were consistent with the aging MCL.

Effects of mechanical stretching on the morphology and cytoskeleton of vaginal fibroblasts from women with pelvic organ prolapse

Mechanical load and postmenopausal hypoestrogen are risk factors for pelvic organ prolapse (POP). In this study, we applied a 0.1-Hz uniaxial cyclic mechanical stretching (CS) with 10% elongation and 10⁻⁸ M 17-β-estradiol to vaginal fibroblasts isolated from postmenopausal women with or without POP to investigate the effects of CS and estrogen on cell morphology and cytoskeletons of normal and POP fibroblasts. Under static culture condition, POP fibroblasts exhibited lower cell circularity and higher relative fluorescence intensities (RFIs) of F-actin, α-tubulin and vimentin. When cultured with CS, all fibroblasts grew perpendicular to the force and exhibited a decreased cell projection area, cell circularity and increased cell length/width ratio; normal fibroblasts exhibited increased RFIs of all three types of cytoskeleton, and POP fibroblasts exhibited a decreased RFI of F-actin and no significant differences of α-tubulin and vimentin. After being cultured with 17-β-estradiol and CS, normal fibroblasts no longer exhibited significant changes in the cell projection area and the RFIs of F-actin and α-tubulin; POP fibroblasts exhibited no significant changes in cell circularity, length/width ratio and F-actin even with the increased RFIs of α-tubulin and vimentin. These findings suggest that POP fibroblasts have greater sensitivity to and lower tolerance for mechanical stretching, and estrogen can improve the prognosis.

Histo-mechanical properties of the swine cardinal and uterosacral ligaments

The focus of this study was to determine the structural and mechanical properties of two major ligaments that support the uterus, cervix, and vagina: the cardinal ligament (CL) and the uterosacral ligament (USL). The adult swine was selected as animal model. Histological analysis was performed on longitudinal and cross sections of CL and USL specimens using Masson׳s trichrome and Verhoeff-van Giesson staining methods. Scanning electron microscopy was employed to visualize the through-thickness organization of the collagen fibers. Quasi-static uniaxial tests were conducted on specimens that were harvested from the CL/USL complex of a single swine. Dense connective tissue with a high content of elastin and collagen fibers was observed in the USL. Loose connective tissue with a considerable amount of smooth muscle cells and ground substance was detected in both the CL and USL. Collagen fibers, smooth muscle cells, blood vessels, and nerve fibers were arranged primarily in the plane of the ligaments. The USL was significantly stronger than the CL with higher ultimate stress and tangent modulus of the linear region of the stress-strain curve. Knowledge about the mechanical properties of the CL and USL will aid in the design of novel mesh materials, stretching routines, and surgical procedures for pelvic floor disorders.

Urogynecological effects of menopause

The menopause signifies a period after significant hormonal change that affects all estrogen-sensitive tissues. This change may result in symptoms affecting any part of the urogenital system. These changes can significantly affect women's health and quality of life. The menopause is associated with lower urinary tract symptoms, vulvovaginal symptoms and pelvic organ prolapse. In this article, we have aimed to describe the symptomatology along with pathophysiology of the effects of menopause on urogynecological problems affecting women's health. Other factors apart from menopause add to these symptoms, like parity, mode of delivery, obesity, smoking and poor psychological health.

Long-term safety of ospemifene (52-week extension) in the treatment of vulvar and vaginal atrophy in hysterectomized postmenopausal women

OBJECTIVE

To examine the long-term safety of oral ospemifene, a non-estrogen tissue-selective estrogen agonist/antagonist, for the treatment of moderate to severe dyspareunia, a symptom of vulvar and vaginal atrophy (VVA) due to menopause.

STUDY DESIGN

This multicenter, long-term, open-label, safety extension study was conducted in women without a uterus aged 40-80 years (N=301) who received oral ospemifene 60 mg/day for 52 weeks. Participants either continued their 60-mg/day ospemifene dose from the initial 12-week pivotal efficacy study or switched from blinded placebo or ospemifene 30 mg/day to open-label ospemifene 60 mg/day. The 52-week open-label extension period plus initial 12-week treatment period totaled up to 64 weeks of ospemifene exposure. A 4-week posttreatment follow-up ensued (68 weeks total).

MAIN OUTCOME MEASURES

Safety assessments included adverse events, laboratory studies, physical and gynecologic examination, vital signs, breast palpation, and mammography.

RESULTS

Most treatment-emergent adverse events (TEAEs) during the extension study were mild or moderate in severity. The most common TEAE related to study drug was hot flushes (10%; leading to discontinuation for 2% of patients). One serious TEAE, a non-ST-elevation myocardial infarction in a patient with pre-existing cardiac disease, was considered possibly related to study medication. One mild breast-related TEAE, considered unrelated to study drug, was ongoing at study completion. There were no instances of pelvic organ prolapse, incontinence, venous thromboembolism, fractures, breast cancers or death. No clinically significant adverse changes were observed in other safety parameters.

CONCLUSIONS

Ospemifene is clinically safe and generally well tolerated in postmenopausal patients with dyspareunia, a symptom of VVA.

Expression of matrix metalloproteinase-1 in round ligament and uterosacral ligament tissue from women with pelvic organ prolapse

To evaluate the matrix metalloproteinase-1 (MMP-1) expression in different parts of pelvic connective tissue in postmenopausal women with and without pelvic organ prolapse (POP). Ninety-one samples were obtained from only postmenopausal women (42 with POP and 49 non-POP subjects). All women were evaluated by pelvic organ prolapse quantitation. The POP group had stage 2 or more, and the controls had stage 1 or less. Round ligament (RL) and uterosacral ligament (USL) biopsies were obtained from women with POP and controls. Immunohistochemistry for MMP-1 was performed on formalin-fixed and paraffin-embedded sections. The two groups were matched for age, body mass index, parity and postmenopausal status. MedCalc Statistical Software Programme Version 12.0.5 was used for statistical analysis. Expression of MMP-1 were significantly higher in both RL and USL tissue from postmenopausal women with POP, compared with controls. MMP-1 immunoreactivities were identified in both RL and USL biopsies from all women with and without POP. The expression pattern of MMP-1 were similar in these ligaments and were significantly higher in POP group compared with control subjects. These changes indicate a possible relation between MMP-1 expression of RL and USL in women with and without POP.

The role of smooth muscle cells in the pathophysiology of pelvic organ prolapse

Pelvic organ prolapse (POP) is a prevalent and disabling condition. The pathophysiology of prolapse is multifactorial, and no single mechanism adequately explains all aspects of its development. The pathophysiology of POP is complex and incompletely understood. Smooth muscle (SM), an integral part of the vaginal wall and endopelvic structures that support the pelvic viscera, has also been implicated in the pathophysiology of POP. In this article, we review the role of smooth muscle cells (SMC) in the pathophysiology of POP, also addressing the anatomy of SM in pelvic floor, morphometric analysis, biomechanical properties, and potential mechanisms.

Relaxin and gonadal steroid receptors in uterosacral ligaments of women with and without pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

This study evaluates the expression of estrogen receptor isoforms alpha (ERα) and beta (ERβ), progesterone receptor (PR), and relaxin receptor isoforms 1 and 2 (LGR7, LGR8) in uterosacral ligament (USL) tissue of women with pelvic organ prolapse and controls.

METHODS

Tissue samples of USL from women with and without pelvic organ prolapse (POP) were subjected to immunohistochemistry against ERα, ERβ, PR, and LGR7 proteins. The respective mRNA expression as well as of LGR8 was assessed by quantitative real-time polymerase chain reaction.

RESULTS

The cellular distribution of the receptor proteins was different due to cell types, independent of POP: ERα and PR were found in smooth muscle cells, but not in endothelial cells, whereas ERβ was found in endothelial cells, but not in connective tissue. ERα, ERβ, PR, and LGR7 mRNAs could be detected in all patients of both groups. ERα mRNA expression was significantly and ERβ mRNA borderline significantly higher in USL of patients with POP: ERα: p < 0.001, ERβ: p = 0.057.

CONCLUSIONS

Enhanced effects of estrogen via altered mRNA expression patterns of ERα and ERβ--but not those of progesterone--may exist in USL of patients affected by POP. A local effect of relaxin needs to be further clarified because of this first report of prevalent ligamental expression of LGR7.

Genitourinary prolapse and joint hypermobility are associated with altered type I and III collagen metabolism

PURPOSE

The aim of this study was to determine whether benign joint hypermobility (BJH) is associated with urogenital prolapse and altered collagen metabolism.

METHODS

43 postmenopausal women with previous vaginal hysterectomy operated due to genitourinary prolapse were recruited. Each patient was also evaluated for joint hypermobility. The collagen metabolism was studied measuring serum concentrations of type I and III procollagen aminoterminal propeptides and trivalently cross-linked carboxyterminal telopeptide of type I collagen.

RESULTS

Clinical joint hypermobility was found in 35% patients. Women with joint hypermobility had higher concentration of aminoterminal propeptide for type I procollagen and the values were statistically significant (P < 0.0178). Recurrent prolapse was found in 47% of the patients with BJH as compared to non-hypermobile group (25%). In this subgroup the results were statistically significant (P < 0.0085) for type III collagen. Also, the mean serum concentration for type III procollagen was significantly increased above the reference limit.

CONCLUSIONS

Women with joint hypermobility have more recurrent genital prolapse as compared to women with normal joint mobility. Plain hypermobility was associated with higher concentrations for type I procollagen. Patients with recurrent prolapse and joint hypermobility have significantly high concentrations for type III procollagen.

Effect of hormone replacement and selective estrogen receptor modulators (SERMs) on the biomechanics and biochemistry of pelvic support ligaments in the cynomolgus monkey (Macaca fascicularis)

OBJECTIVE

To evaluate the effect of selective estrogen receptor modulators and ethinyl estradiol on the biomechanical and biochemical properties of the uterosacral and round ligaments in the monkey model of menopause.

STUDY DESIGN

A randomized, double-blind, placebo-controlled study on 11 female macaque monkeys. Ovariectomized monkeys received 12 weeks of placebo, raloxifene, tamoxifen, or ethinyl estradiol. Biomechanical step-strain testing and real-time polymerase chain reaction was performed on the uterosacral and round ligaments.

RESULTS

Tamoxifen and raloxifene uterosacrals expressed differing collagen I/III receptor density ratios, but both selective estrogen receptor modulators showed decreased tensile stiffness compared to ethinyl estradiol and controls.

CONCLUSION

These findings support a possible effect of selective estrogen receptor modulators on biomechanical and biochemical properties of uterosacrals. This may play a role in pelvic organ prolapse.

Comparison of Human to Macaque Uterosacral–Cardinal Ligament Complex and Its Relationship to Pelvic Organ Prolapse

The uterosacral–cardinal ligament complex is thought to be the critical structure responsible for uterine and apical vaginal support. It is ill defined and can be difficult to dissect in the cadaver lab and in the operating room. Even less information is available on the analogous structures in the monkey model. We present this report to bring together what little is known to aid in studying this model and pelvic organ prolapse (POP), and to point out the need for critical assessment of this hormone-responsive tissue in the process of drug development.

Competing Interests: This article was sponsored by Covance Inc. and Schering-Plough. The authors did not declare any other competing interests.

Differential elastin and tenascin immunolabeling in the uterosacral ligaments in postmenopausal women with and without pelvic organ prolapse

Connective tissue, consisting mainly of collagen and structural glycoproteins, is an important part of the supportive structures of the genitourinary region. Relatively few data have been published with respect to the role of elastin and glycoproteins in pelvic organ prolapse (POP). Connective tissue of the uterosacral ligament in postmenopausal women with and without genital prolapse was compared. Fifty-nine consecutive women referred for hysterectomy were included in the study. The patients had POP or benign gynecological disease (e.g. myoma of the uterus). Tissue samples from the uterosacral ligament were investigated for localization and distribution of tenascin and elastin using immunofluorescence microscopy. Tissue samples of women with prolapse showed a significantly (p<0.001) weaker immunofluorescent labeling of tenascin compared to samples taken from women without prolapse. Tenascin was detectable in tissues of all women with POP, whereas its immunolabeling was decreased in the uterosacral ligament in women without POP. Intact elastin fibers were observed in tissues of all women without POP, whereas elastin was undetectable or sometimes fragmented in the uterosacral ligament in women with POP. Greater amounts of tenascin and lesser amounts of elastin were therefore found in patients with POP. These results suggest that an altered turnover of connective tissue in the uterosacral ligament might be responsible for the presence of pelvic floor relaxation in postmenopausal women. These data indicate a complex architecture of the extracellular matrix in the uterosacral ligaments, with marked differences in tenascin and elastin expression between postmenopausal women with or without POP.

Quantitative determination of progesterones and corticosteroids in human urine using gas chromatography/mass spectrometry: application to pelvic organ prolapse patients

A quantitative analytical method using gas chromatography/mass spectrometry (GC/MS) to determine urinary concentrations of eight progesterones and corticosteroids has been developed. After enzymatic hydrolysis with beta-glucouronidase/arylsulfatase, urine samples were extracted by simple one-step solid-phase extraction. Obtained extracts were derivatized with a mixture of N-methyl-N-(trimethylsilyl)trifluoroacetamide/ammonium iodide/dithiothreitol and determined by GC/MS in selected ion monitoring mode to increase the sensitivity. d(4)-Cortisol and d(9)-progesterone were used as internal standards for two different steroid groups. The linear correlation coefficient was in the range of 0.9913 to 0.9998 and recoveries were over 80% for all compounds. Precision and accuracy were in the range of 0.9-18.1 and 84.1-118.7%, respectively. The limit of quantitation (LOQ) was 10 ng/mL for 11-deoxycorticosterone and 21-deoxycortisol and 5 ng/mL for all other analytes. The developed method was successfully applied on pelvic organ prolapsed patients (n = 10, age: 67.9 +/- 4.9) and post-menopausal (n = 10, age: 63.6 +/- 5.5) control women. Urinary levels of most progesterones and corticosteroids except 11-deoxycorticosterone decreased but only that of 17 alpha-hydroxyprogesterone significantly decreased in patients compared with the control groups. Thus, it is concluded that progesterones could be a factor in the pathogenesis of pelvic organ prolapse, and, among them, 17 alpha-hydroxyprogesterone could be a biomarker for pelvic organ prolapse.

Alterations of estrogen receptor-α and -β in the anterior vaginal wall of women with urinary incontinence

OBJECTIVES

The objective was to investigate the alterations in estrogen receptor-alpha and -beta (ER-alpha and ER-beta) in the anterior vaginal wall of women with stress urinary incontinence (SUI).

STUDY DESIGN

Samples of the anterior vaginal wall were taken from 57 women, including 12 women with premenopausal SUI (pre-M SUI), 12 with premenopausal control (pre-M control), 19 with postmenopausal SUI (post-M SUI), and 14 with postmenopausal control (post-M control). The expressions of ER-alpha and ER-beta were assayed by immunohistochemistry and quantified with the H-score method.

RESULTS

Serum estradiol was significantly lower in the pre-M SUI than in the pre-M control group (P<0.01), but the difference between the post-M SUI and post-M control groups was not significant (P>0.05). ER-alpha in endothelia, smooth muscle cells, and fibrocytes were significantly lower in pre-M SUI than in pre-M control (P<0.01), but there were no significant differences of ER-alpha between the post-M SUI and post-M control groups (P>0.05). ER-beta in endothelia and fibrocytes were significantly lower in the pre-M SUI than in the pre-M control group (P<0.01), and ER-beta in fibrocytes was significantly lower in the post-M SUI than in the post-M control group (P<0.01).

CONCLUSIONS

Alterations in serum estradiol and its receptors (ER-alpha and ER-beta) in the anterior vaginal wall were demonstrated, suggesting their involvement in the occurrence of female SUI.

Roles of sex steroid receptors and cell cycle regulation in pathogenesis of pelvic organ prolapse

PURPOSE OF REVIEW

The cause of pelvic organ prolapse is multifactorial and many inciting, promoting and decompensating factors play a role in developing pelvic organ prolapse. Various clinical parameters have been studied quite extensively, but estrogen and collagen metabolism and cell proliferation and apoptosis have not been widely evaluated. This review focuses on assessing the roles of estrogen and its receptor, relationship with collagen metabolism and cell proliferation and cell apoptosis in development and progression of pelvic organ prolapse.

RECENT FINDINGS

Differential expressions of sex steroid receptors in various suspensory ligaments of prolapsed uteri have been studied. How different subtypes of estrogen receptor play a role in inducing and aggravating pelvic organ prolapse has yet to be defined. The role of estrogen in collagen metabolism and cell proliferation related to development of pelvic organ prolapse is still under study. Studies on the proliferation of fibroblasts in ligaments of pelvic organ prolapse have yielded conflicting results.

SUMMARY

There is still a need for additional research on precise roles of sex steroids, their receptors and cell cycle regulatory proteins and cell proliferation in pathogenesis of pelvic organ prolapse. Some of them could be the cause of pelvic organ prolapse and some of them the direct result of tissue trauma in pelvic organ prolapse.

Association of cutis laxa and genital prolapse: a case report

Cutis laxa (CL) is an extremely inherited or acquired connective tissue disorder characterised by a markedly reduced systemic elastin content. Genital abnormalities in patients with CL have been rarely reported. We report such a case in a 48-year-old CL patient affected by genital prolapse, focusing on immunohistological and molecular biology assessment of elastin and collagen type I, III, VI content in the main uterine ligaments. The woman was referred to our department for the onset of a rapidly progressing genital prolapse and urinary incontinence. The patient underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy and sacrocolpopexy. Punch biopsies from both cardinal and uterosacral ligaments revealed a dramatic reduction in elastin and an increase in collagen type VI content. The present report seems to underline the central role exerted primarily by elastin in the supportive connective tissue and might contribute to the knowledge of extracellular matrix abnormalities at the basis of genital abnormalities in CL patients.

Steroid receptor expression in vaginal epithelium of healthy fertile women and influences of hormonal contraceptive usage

BACKGROUND

The objective of this study was to evaluate whether long-term usage of hormonal contraceptives modifies the steroid receptor expression in the human vaginal epithelium of healthy young women.

METHODS

In a cross-sectional study, three groups of hormonal contraceptive users [combined oral contraceptives (COCs), levonorgestrel implants (LNG) and depot medroxyprogesterone acetate injections (DMPAs)] were compared to controls. Fifteen subjects (20-34 years) were enrolled to each group. Vaginal biopsies were collected at two occasions from each subject, and serum concentrations of E(2) and progesterone were measured. Monoclonal antibodies directed against progesterone receptors (PRs) and estrogen receptors (ERs) were used in immunohistochemistry on formalin-fixed tissue sections of vaginal mucosa. A program for immunohistomorphometric quantification was devised to estimate frequency of epithelial steroid receptor-expressing cells.

RESULTS

Progesterone receptor expression was markedly down-regulated and significantly reduced in DMPA users compared to controls, COC and LNG users. In DMPA users, the ER expression was significantly elevated in the first compared to the second sample, and significantly elevated compared to LNG users. Estradiol concentration in serum was significantly reduced in hormonal contraceptive users compared to controls.

CONCLUSIONS

Steroid receptor expression in human vaginal epithelium is altered by long-term use of DMPA compared to controls.

Urogynaecology: Collagen metabolism in the uterosacral ligaments and vaginal skin of women with uterine prolapse

OBJECTIVE

To compare tissue markers of collagen metabolism in the uterosacral ligaments with those in vaginal tissue in women with uterine prolapse.

DESIGN

Prospective observational experimental study.

SETTING

A tertiary urogynaecology unit.

POPULATION

Women referred for hysterectomy for prolapse or benign gynaecological disease.

METHODS

Matrix metalloproteinase (MMP)-2 and -9 expression, tissue inhibitors of metalloproteinase (TIMP)-2 expression and hydroxyproline content were measured in the uterosacral ligaments and vaginal tissue from 14 women with prolapse compared with 14 controls.

MAIN OUTCOME MEASURES

Levels of MMP, TIMP and hydroxyproline in the uterosacral ligaments and vaginal tissue of women with prolapse and controls.

RESULTS

Fourteen women with prolapse and 14 women without prolapse (controls) were included. A significant increase in pro MMP-2 expression was seen in vaginal tissue from women with prolapse (P < 0.05) but not activated MMP-2, MMP-9 and TIMP-2. For uterosacral ligaments, the differences were not statistically significant. No significant difference in hydroxyproline content was found between control and prolapse in either tissue. Significant correlations exist in expression of pro-MMP-2, activated MMP-2, MMP-9 and TIMP-2 in vaginal tissue with that in uterosacral ligaments.

CONCLUSIONS

Correlations existed between markers of collagen metabolism in the vaginal and uterosacral tissues. This suggests vaginal tissue reflects the endopelvic fascia. The changes which are more pronounced in vaginal tissue may be as a result of prolapse rather than cause.

17β-Estradiol suppresses proliferation of fibroblasts derived from cardinal ligaments in patients with or without pelvic organ prolapse

BACKGROUND

Estrogen replacement therapy (ERT) has been used in the treatment of pelvic organ prolapse (POP) but clinical results are inconclusive. The purpose of this study was to investigate the effect of 17beta-estradiol (E(2)) on the proliferation of fibroblasts derived from cardinal ligaments in women with or without POP.

METHODS

Fibroblasts were derived from seven patients with POP and seven age-matched controls. The growth rate of POP fibroblasts was compared with that of control by 3-(4,5,-dimethyl thiazolyl-2)-2,5-diphenyl tetrazolium bromide (MTT) assay. Four cell strains from each patient and control group were treated with different concentrations of E2 (10(-4), 10(-8), 10(-9) and 10(-10) mol/l). The effect of E2 on cell proliferation was then measured by MTT assay.

RESULTS

The overall growth rate of POP fibroblasts was significantly slower than that of controls under normal culture conditions. Addition of E2 suppressed cell proliferation of all the fibroblasts, especially in POP fibroblasts. POP fibroblasts showed a significantly lower proliferative rate than that of controls at all E2 concentrations, with the most prominent inhibitory effect at physiological concentration (10.83 34.41% versus 81.56 48.10% at 10(-8) mol/l).

CONCLUSIONS

Our results suggest that decreased fibroblast turnover may contribute to the development of POP; and ERT may not be an effective POP treatment.

Roles of estrogen receptor, progesterone receptor, p53 and p21 in pathogenesis of pelvic organ prolapse

The aim of this study is to compare the levels of estrogen receptor (ER), progesterone receptor (PR), p53 and p21 between pelvic organ prolapse (POP) and control groups in order to evaluate their roles in pathogenesis of POP, and to find out the relationship among these proteins. Through the year of 2002, uterosacral ligaments were obtained from 20 prolapsus and 24 non-prolapsus hysterectomized uteruses. ER, PR, p53, and p21 proteins were extracted by Western blot analysis and relative levels of proteins were compared by Student t-test and Pearson correlation coefficient. P value <0.05 was considered statistically significant. All patients were postmenopausal and had never taken hormone replacement therapy. ER, PR, p53, and p21 were significantly lower in the study than control group (p<0.0001). Positive correlations were found among all proteins in the prolapse group. Further researches are needed to elucidate the interrelationship among these proteins and their precise roles in pathogenesis of POP.

The effects of hormone replacement on the biomechanical properties of the uterosacral and round ligaments in the monkey model

OBJECTIVE

The purpose of this study was to determine effects of ovariectomy (OVX) and conjugated equine estrogens plus medroxyprogesterone acetate (CEE/MPA), or ethinyl estradiol plus norethindrone acetate (EE/NA) on biomechanics of uterosacral (USL) and round (RL) ligaments in postmenopausal (PMP) monkeys.

STUDY DESIGN

This was a randomized, triple blind, placebo-controlled study. OVX monkeys received 12 months no treatment (Pbo) (n = 19), CEE/MPA (n = 19), or EE/NA (n = 21). USL and RL step strains and stress-relaxation data were curve-fitted, giving strain-dependent tensile modulus (TM) from 0% to 30%.

RESULTS

(1) USL: TM for both treatment groups was greater than Pbo for strains from 0% to 12% (P < .04). (2) RL: TM for both treatment groups was smaller than Pbo for strains from 12% to 30% (P < .05). No differences were found between treatment regimens.

CONCLUSION

CEE/MPA and EE/NA both affect functional biomechanical properties by increasing tensile stiffness in the USL and decreasing it in the RL.

Short-term urogenital effects of raloxifene, tamoxifen, and estrogen

OBJECTIVE

The purpose of this study was to assess the urogenital effects of raloxifene, tamoxifen, conjugated equine estrogen, and placebo in healthy postmenopausal women.

STUDY DESIGN

This randomized, double-blind, placebo-controlled study compared the urogenital effects of 0.625 mg of conjugated equine estrogen (n = 15 women), 20 mg of tamoxifen (n = 14 women), 60 mg of raloxifene, (n = 15 women), and placebo (n = 13 women). Evaluations at baseline and evaluations after 20 weeks receiving the drug included a pelvic examination with cytologic evaluation of vagina and urethra, pelvic organ prolapse quantitation, and urethral axis deflection by cotton swab test (only in patients with incontinence [33%]).

RESULTS

Conjugated equine estrogen increased the maturation value of both urethral and vaginal cytologic condition (P =.002, P =.032, respectively). There was a decrease in vaginal maturation value in the raloxifene group (not significant). Two of 8 women in the conjugated equine estrogen group showed evidence of worsening prolapse by pelvic organ prolapse quantitation; the condition of 2 of 8 women improved. In the raloxifene, tamoxifen, and placebo groups 8 of 12 women, 4 of 13 women, and 2 of 11 women had worsening in prolapse scores, respectively, whereas none of the women had improvement. Increased cotton swab deflection was found in 3 of 5 women in the raloxifene group, in 5 of 8 women in the tamoxifen group, in 0 of 4 women in the placebo group, and in 0 of 2 women in the conjugated equine estrogen group. Seventy-five percent of the patients who received raloxifene and 60% of the patients who received tamoxifen had increases in prolapse by any measure (ie, pelvic organ prolapse quantitation or cotton swab or clinical assessment) compared with 18% of the patients in the placebo group and 22% of the patients in the conjugated equine estrogen group (P =.015), although symptoms did not differ among groups.

CONCLUSION

Neither raloxifene nor tamoxifen improve cytohormonal effects in the vagina or urethra, whereas conjugated equine estrogen does. Raloxifene and tamoxifen appear to show worsening prolapse compared with conjugated equine estrogen and placebo. The clinical relevance of these effects is unknown and requires investigation.

Differences in estrogen modulation of tissue inhibitor of matrix metalloproteinase-1 and matrix metalloproteinase-1 expression in cultured fibroblasts from continent and incontinent women

OBJECTIVE

The purpose of this study was to investigate the effect of increasing estrogen concentrations on metalloproteinase and tissue inhibitors of metalloproteinase protein expressions in cultured pelvic fibroblasts that were obtained from continent and incontinent women.

STUDY DESIGN

Periurethral vaginal wall tissues were taken from four stress incontinent and three continent premenopausal women who underwent gynecologic surgery for benign indications. Protein was extracted from these tissues, and Western blot analysis was performed to document that fibroblasts from continent and incontinent women differed with respect to metalloproteinase and tissue inhibitors of metalloproteinase production. One age-matched tissue pair was prepared for fibroblast culture. Cells were cultured with increasing concentrations of estradiol (0-500 pg/mL). Extracellular metalloproteinase and tissue inhibitors of metalloproteinase were assessed semiquantitatively with Western blotting.

RESULTS

Periurethral vaginal tissues from incontinent women expressed less tissue inhibitors of metalloproteinase when compared with tissue from the control subjects; there was no difference in the expression of cleaved, active metalloproteinase protein. Tissue inhibitors of metalloproteinase expression from fibroblasts of continent women significantly increased with increasing estradiol concentrations (0-100 pg/mL, P <.05). No significant dose response was seen in fibroblasts from an incontinent woman. Metalloproteinase expression was not altered by increasing estradiol concentrations in fibroblasts from either continent or incontinent women.

CONCLUSION

This preliminary in vitro study suggested that, in fibroblasts that were derived from the continent woman, tissue inhibitors of metalloproteinase protein production increases with increasing estrogen levels and that, in stress incontinent fibroblasts, no similar increase occurs. Neither group demonstrated a change in metalloproteinase production in response to varying estrogen levels, which suggests that estrogen may inhibit collagen degradation in continent women by increasing tissue inhibitors of metalloproteinase production but exerts a reduced inhibitory effect on collagenolysis in women with stress urinary incontinence.

Pelvic connective tissue resilience decreases with vaginal delivery, menopause and uterine prolapse

BACKGROUND

The late onset of pelvic visceral prolapse and incontinence after childbirth injury could be explained by menopause-associated connective tissue weakening. Uterosacral ligament resilience (UsR) was assessed to determine whether it influenced uterine or pelvic floor mobility, or varied with age, vaginal delivery, menopause or histological variations in the ligament.

METHODS

UsR was measured by tensiometry in ligaments from 85 hysterectomy specimens, and was correlated with the presence of symptomatic uterocervical prolapse, prehysterectomy uterine and anorectal mobility, patient age, history of vaginal delivery and menopause. Forty-five of these ligaments were examined for ligament thickness, muscle to collagen ratio, and oestrogen and progesterone receptor density. The results were correlated with UsR.

RESULTS

UsR was significantly reduced (P = 0.02) in symptomatic uterovaginal prolapse, but there was no correlation with either uterocervical or anorectal descent in women without symptomatic prolapse. There was a significant decrease in UsR with vaginal delivery (P = 0.003), menopause (P = 0.009) and older age (P = 0.005). The uterosacral ligament was significantly thinner and contained fewer oestrogen and progesterone receptors after menopause, but this did not affect UsR.

CONCLUSION

Where pelvic floor muscles are weakened, decreases in pelvic connective tissue resilience related to the menopause may facilitate progression to symptomatic pelvic visceral prolapse.

Regulation of matrix metalloproteinase expression by estrogen in fibroblasts that are derived from the pelvic floor

OBJECTIVE

The purpose of this study was to determine whether estrogen suppresses matrix metalloproteinase-2 and -9 proenzyme expression by fibroblasts that are derived from the supportive connective tissue of the pelvic floor.

STUDY DESIGN

A primary fibroblast culture that was developed from a biopsy specimen of the arcus tendineus was treated with interleukin-1 beta (10-15 ng/mL), transforming growth factor-beta 1 (5-15 ng/mL), 17 beta-estradiol (10(-9)-10(-7) mol/L), and Imperial Chemical Industries (ICI) 182 780 (10(-8)-10(-6) mol/L). Cellular and extracellular protein were analyzed by Western blotting and substrate zymography, respectively, for the effect of each treatment on the amount of pro-matrix metalloproteinase-2 and -9 and the membrane type 1 matrix metalloproteinase protein.

RESULTS

Both cellular and extracellular pro-matrix metalloproteinase-2 protein were increased by transforming growth factor-beta1 (P =.01) and decreased by estradiol (P <.001) and ICI 182 780 (P =.02 and.002, respectively). Membrane type 1 matrix metalloproteinase was not affected by estradiol, ICI 182 780, interleukin-1 beta, or transforming growth factor-beta 1. Extracellular pro-matrix metalloproteinase-9 was increased by the cytokines interleukin-1 beta (P <.001) and transforming growth factor-beta1 (P <.001) and decreased by estradiol (P <.001) and ICI 182 780 (P <.001).

CONCLUSION

The proenzymes of the tissue-degrading matrix metalloproteinases -2 and -9 are decreased by 17-beta estradiol and ICI 182 780.

Expression of estrogen receptor isoforms alpha and beta messenger RNA in vaginal tissue of premenopausal and postmenopausal women

OBJECTIVE

To determine the messenger RNA expression patterns of estrogen receptor (ER)alpha and ER beta in human vaginal tissue.

STUDY DESIGN

Reverse transcriptase-polymerase chain reaction was performed on tissue samples of 75 patients having anterior colporrhaphy (25 premenopausal, 25 postmenopausal receiving estrogen replacement therapy [ERT], 25 postmenopausal not receiving ERT). Levels of mRNA were normalized and ratios were calculated to assess relative levels of expression.

RESULTS

All samples showed expression of the ER alpha isoform. Significant differences existed in ER alpha expression among the 3 cohorts (P =.023). Greater differences (P <.001) existed in ER beta expression. For both isoforms, the premenopausal group had the highest level, and the postmenopausal group receiving ERT had the lowest level. No significant difference in ER beta expression existed between postmenopausal groups.

CONCLUSION

Significant differences exist between premenopausal and postmenopausal women in presence and expression of ER alpha and ER beta in vaginal tissue. Expression of ER beta markedly declines in menopause, regardless of ERT use.

Estrogen, progesterone, and androgen receptor expression in levator ani muscle and fascia

Previous studies have reported controversial data on estrogen receptor (ER) expression in levator ani muscle. We investigated ER expression in levator ani muscle and fascia and compared it with the expression of progesterone receptor (PR) and androgen receptor (AR). The study included 55 women undergoing surgery for gynecological (asymptomatic, n = 10) or urogynecological conditions (symptomatic, n = 45). The asymptomatic and 21 of the symptomatic women received no hormone replacement therapy (HRT). The remaining 24 symptomatic women received some form of HRT. Biopsies were taken from the levator ani muscle and the overlying fascia, and quantitative measurements of immunohistochemical staining by image analysis were made. None of the levator ani muscle samples showed any evidence of nuclear ER expression in striated muscle fibers, but some cells in the muscular stroma did express ER. However, PR and AR expression was found in both muscle and stromal cells. Levator ani fascia showed nuclear ER, PR, and AR expression to varying degrees. There was a significant increase (p < 0.03) in ER expression in levator ani fascia of symptomatic patients without HRT when compared with asymptomatic age-matched women. The ER expression was significantly lower (p < 0.001) in postmenopausal symptomatic women receiving long-term estrogen replacement compared with age-matched women without HRT. Our data indicate that ER expression is significantly higher in symptomatic women compared with age-matched asymptomatic females. However, long-term estrogenization causes significant decrease of ER expression.

Evidence of progesterone receptors in the mucosa of the urinary bladder

OBJECTIVE

To investigate whether progesterone receptors are present in the mucosa of the urinary bladder of continent premenopausal women compared with continent postmenopausal women.

MATERIALS AND METHODS

Fifty-seven biopsies from the mucosa of the trigone and lateral wall of the urinary bladder were examined by the avidin-biotin-peroxidase immunohistochemical technique for the presence of estrogen and progesterone receptors. The specimens were obtained at cystoscopy performed to investigate hematuria in 42 patients and neoplasia in 15. The study group (n = 29) comprised non-pregnant premenopausal women in the luteal phase of their menstrual cycle and the control group (n = 28) comprised postmenopausal women. None of the subjects had urinary incontinence or was taking medication with hormones. In no case did the primary lesion involve the specimen used for laboratory analysis.

RESULTS

There was positive immunostaining with estrogen in 28 patients of the study group (96.5%) and 4 (14.4%) in the control group (p<0.0001). The 28 samples of the study group also showed positive immunostaining for progesterone receptors. There was positive immunostaining with progesterone in 18 samples (64.3%) of the control group (p<0.01). Fourteen samples (50%) of the control group thus showed positive immunostaining for progesterone but no evidence of positive immunostaining with estrogen. Immunostaining for estrogen and progesterone receptors was similar in trigonal and lateral wall samples.

CONCLUSION

In continent pre- and post-menopausal women, a direct progestogenic effect on the mucosa of the urinary bladder seems likely in addition to estrogen.

Estrogen receptor alpha and beta expression in the vaginal walls and uterosacral ligaments of premenopausal and postmenopausal women

OBJECTIVE

To assess the expression of messenger RNA (mRNA) for estrogen receptors alpha and beta in the vaginal walls and uterosacral ligaments of premenopausal and postmenopausal women.

DESIGN

In vitro experiment.

SETTING

Academic research environment.

PATIENT(S)

Sixteen consecutively seen women who underwent hysterectomy.

INTERVENTION(S)

Samples of anterior vaginal walls and uterosacral ligaments were obtained during hysterectomy.

MAIN OUTCOME MEASURE(S)

Reverse transcriptase-polymerase chain reaction analysis for estrogen receptor mRNA.

RESULT(S)

Messenger RNA transcripts for estrogen receptor alpha were present in all samples of vaginal walls (16/16) and uterosacral ligaments (16/16). Estrogen receptor beta mRNA was detected in all samples of vaginal walls from premenopausal women (12/12) but in none of those from postmenopausal women (0/4). Estrogen receptor beta mRNA was found in most samples of uterosacral ligaments from premenopausal women (10/12) and in some of those from postmenopausal women (2/4).

CONCLUSION(S)

Estrogen receptors alpha and beta were expressed in the vaginal walls and uterosacral ligaments of premenopausal and postmenopausal women. Estrogen receptor beta was absent from the vaginal walls of postmenopausal women.

Pregnancy-induced changes in rabbit medial collateral ligament vasoregulation

The ligaments of weight-bearing joints are known to become mechanically inferior during pregnancy, and it has been postulated that this may be due to changes in tissue perfusion. Calcitonin gene-related peptide (CGRP) and epinephrine exert a tonic influence on the vasculature of the medial collateral ligament (MCL), and the present study examined whether these vasoactive influences were altered by pregnancy. Ligament perfusion experiments were performed on primigravid New Zealand White rabbits with the use of laser Doppler perfusion imaging. In pregnant animals (day 29), MCL basal perfusion fell significantly compared with control; however, values returned to normal 5 days postpartum. In normal joints, topical application of CGRP resulted in a dose-dependent increase in MCL perfusion, whereas epinephrine administration caused a dose-dependent fall in blood flow. During pregnancy, the vasodilator effect of CGRP was completely abolished, whereas adrenergic vasoconstriction was greater than normal. Both responses returned postpartum. Pregnancy in the rabbit produces hypoemia in the MCL, and this phenomenon may be effected by a tempering of CGRP dilator responses and an augmentation of alpha-adrenoceptor-mediated vasoconstriction.