Basic science and translational research in female pelvic floor disorders: proceedings of an NIH-sponsored meeting

Pregnancy, labour and delivery as risk factors for pelvic organ prolapse: a systematic review

INTRODUCTION

Pregnancy and childbirth are considered risk factors for pelvic organ prolapse (POP). The long latency between obstetric events and morbidity hinders the establishment of cause-effect relationships. Recently, intermediate outcomes such as organ descent and levator avulsion (LA) have been identified. We aimed to assess the effect of obstetric events on symptoms and signs of POP and on LA.

METHODS

We systematically reviewed the literature by searching PubMed/MEDLINE, Embase and Cochrane Library. We included studies in women examining associations between obstetric events and symptoms and signs of POP and LA, assessed through questionnaires, clinical examination and pelvic floor imaging. Two reviewers evaluated the studies for eligibility and for methodological quality/susceptibility to bias. We extracted study results and clustered them by outcome: symptoms of POP (sPOP), clinical findings of POP (cPOP) and LA. When appropriate, we performed a random-effect meta-analysis and reported the summary odds ratios (OR) with 95% confidence intervals. Heterogeneity across studies was assessed using the I² statistic.

RESULTS

The first vaginal delivery was a risk factor for POP as measured by sPOP (OR: 2.65 [1.81-3.88]), cPOP (OR: 4.85 [2.15-10.94]) and in association with LA (OR: 41.6 [4.13- 419.41]). Forceps delivery was a risk factor for POP as measured by sPOP (OR: 2.51 [1.34-4.69]), cPOP (OR: 1.68 [1.21-2.34]) and in association with LA (OR: 5.92 [3.75-9.34]). Birth exclusively by caesarean was protective for sPOP (OR: 0.38 [0.29-0.51]) and for cPOP (OR: 0.29 [0.20-0.41]) and it did not confer any additional risk compared to nulliparity.

CONCLUSIONS

This review confirms a strong aetiological link between vaginal birth and POP, with the first vaginal and forceps delivery being the main determinants.

Urethral regions with differential tissular composition may underlie urinary continence and voiding function in female rats

AIMS

To analyze, in female rats, the anatomical and histological features of the urethra and its relationship with the vagina and clitoris, and its innervation.

METHODS

Seventeen adult female Wistar rats were used. Gross anatomy and acetylcholinesterase (AchE) histochemistry were performed to describe the urethral features, adjacent structures, and innervation. The histomorphometric characteristics of the urethra were determined in transversal, longitudinal, or coronal sections stained with Masson's Trichrome.

RESULTS

The female rat urethra is not a homogeneous tubular organ. The pre-pelvic and pelvic regions are firmly attached to the vagina with belt-like striated fibers forming a urethra-vaginal complex. The bulbar regions have curved segments and a narrow lumen. The clitoral region is characterized by a urethra-clitoral complex surrounded by a vascular plexus. The lumen area and thickness of the urethral layers significantly varied between regions (P < 0.05). Innervation of the urethra arrives from the major pelvic ganglion, the dorsal nerve of the clitoris (DNC), and the motor branch of the sacral plexus (MBSP).

CONCLUSIONS

Differential tissular composition of the urethra may underlie urinary continence and voiding dysfunction through different physiological mechanisms. The urethra-vagina complex seems to be the main site controlling urinary continence through active muscular mechanisms, while the bulbar urethra provides passive mechanisms and the urethra-clitoris complex seems to be crucial for distal urethral closure by means of a periurethral vascular network.

Collagen metabolic disorder induced by oxidative stress in human uterosacral ligament‑derived fibroblasts: A possible pathophysiological mechanism in pelvic organ prolapse

Pelvic organ prolapse (POP) is a global health problem, for which the pathophysiological mechanism remains to be fully elucidated. The loss of extracellular matrix protein has been considered to be the most important molecular basis facilitating the development of POP. Oxidative stress (OS) is a well-recognized mechanism involved in fiber metabolic disorders. The present study aimed to clarify whether OS exists in the uterosacral ligament (USL) with POP, and to investigate the precise role of OS in collagen metabolism in human USL fibroblasts (hUSLFs). In the present study, 8-hydroxyguanosine (8-OHdG) and 4 hydroxynonenal (4-HNE), as oxidative biomarkers, were examined by immunohistochemistry to evaluate oxidative injury in USL sections in POP (n=20) and non-POP (n=20) groups. The primary cultured hUSLFs were treated with exogenous H₂O₂ to establish an original OS cell model, in which the expression levels of collagen, type 1, α1 (COL1A1), matrix metalloproteinase (MMP)-2, tissue inhibitor of metalloproteinase (TIMP)-2 and transforming growth factor (TGF)-β1 were evaluated by western blot and reverse transcription-quantitative polymerase chain reaction analyses. The results showed that the expression levels of 8-OHdG and 4-HNE in the POP group were significantly higher, compared with those in the control group. Collagen metabolism was regulated by H₂O₂ exposure in a concentration-dependent manner, in which lower concentrations of H₂O₂ (0.1–0.2 mM) stimulated the anabolism of COL1A1, whereas a higher concentration (0.4 mM) promoted catabolism. The expression levels of MMP-2, TIMP-2 and TGF-β1 exhibited corresponding changes with the OS levels. These results suggested that OS may be involved in the pathophysiology of POP by contributing to collagen metabolic disorder in a severity-dependent manner in hUSLFs, possibly through the regulation of MMPs, TIMPs and TGF-β1 indirectly.

Production of ascorbic acid releasing biomaterials for pelvic floor repair

OBJECTIVE

An underlying abnormality in collagen turnover is implied in the occurrence of complications and recurrences after mesh augmented pelvic floor repair surgeries. Ascorbic acid is a potent stimulant of collagen synthesis. The aim of this study is to produce ascorbic acid releasing poly-lactic acid (PLA) scaffolds and evaluate them for their effects on extracellular matrix production and the strength of the materials.

MATERIALS AND METHODS

Scaffolds which contained either l-ascorbic acid (AA) and Ascorbate-2-Phosphate (A2P) were produced with emulsion electrospinning. The release of both drugs was measured by UV spectrophotometry. Human dermal fibroblasts were seeded on scaffolds and cultured for 2weeks. Cell attachment, viability and total collagen production were evaluated as well as mechanical properties.

RESULTS

No significant differences were observed between AA, A2P, Vehicle and PLA scaffolds in terms of fibre diameter and pore size. The encapsulation efficiency and successful release of both AA and A2P were demonstrated. Both AA and A2P containing scaffolds were significantly more hydrophilic and stronger in both dry and wet states compared to PLA scaffolds. Fibroblasts produced more collagen on scaffolds containing either AA or A2P compared to cells grown on control scaffolds.

CONCLUSION

This study is the first to directly compare the two ascorbic acid derivatives in a tissue engineered scaffold and shows that both AA and A2P releasing electrospun PLA scaffolds increased collagen production of fibroblasts to similar extents but AA scaffolds seemed to be more hydrophilic and stronger compared to A2P scaffolds.

STATEMENT OF SIGNIFICANCE

Mesh augmented surgical repair of the pelvic floor currently relies on non-degradable materials which results in severe complications in some patients. There is an unmet and urgent need for better pelvic floor repair materials. Our current understanding suggests that the ideal material should be able to better integrate into sites of implantation both biologically and mechanically. The impact of vitamin C on extracellular matrix production is well established but we in this study have undertaken a critical comparison of two derivatives of vitamin C as they are released from a biodegradable scaffold. This strategy proved to be equally useful with both derivatives in terms of new tissue production yet we observed significant differences in mechanical properties of these biomaterials.

Decreased expression of elastin and lysyl oxidase family genes in urogenital tissues of aging mice

AIM

This study aims to investigate the expression levels of elastin and lysyl oxidase (LOX) family members in the urogenital tissues of natural aging mice and accelerated ovarian aging mice.

METHOD

Uteri, vaginas and bladders were harvested from 18-month-old female mice and accelerated ovarian aging mice developed by chemotherapeutic agents. Untreated 3-month-old female mice were used as controls. The expression levels of elastin and LOX family members were determined by real-time polymerase chain reaction and western blot.

RESULTS

Compared with untreated young female mice, the expression of elastin and LOX family members significantly decreased both in natural aging mice and accelerated ovarian aging mice.

CONCLUSION

Aging is a high-risk factor for pelvic floor disorders. The failure of elastic fiber synthesis and assembly due to the decline in expression levels of elastin and LOX family members during aging may explain the molecular mechanism causing pelvic floor disorders.

Long-term outcomes of laparoscopic repair of cystocoele

BACKGROUND

There is little information on the effectiveness of laparoscopic techniques for native tissue repair of cystocoele.

AIM

To assess the long-term outcome of laparoscopic cystocoele repair.

METHODS

Two hundred and twenty-three women with symptomatic pelvic organ prolapse underwent laparoscopic paravaginal repair and treatment of associated conditions. Women were assessed pre-operatively and postoperatively at 6 weeks, 6 months, 12 months and then annually or biannually with pelvic organ prolapse quantification (POPQ) and subjective assessment at each visit.

RESULTS

Median follow-up was 5.2 years (range: 1-12 years) with 140 women (63%) followed for at least 5 years. During follow-up, 79% of women developed prolapse of at least POPQ stage 2 in one or more compartments and 58% became symptomatic again. Overall, 48% underwent further prolapse surgery, but only 24% of women had an anterior prolapse beyond the hymen. Thirty per cent eventually had a further cystocoele repair.

CONCLUSION

Long-term follow-up of laparoscopic cystocoele repair shows that cystocoeles are difficult to repair successfully.

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.

Genetic epidemiology of pelvic organ prolapse: a systematic review

Given current evidence supporting a genetic predisposition for pelvic organ prolapse, we conducted a systematic review of published literature on the genetic epidemiology of pelvic organ prolapse. Inclusion criteria were linkage studies, candidate gene association and genome-wide association studies in adult women published in English and indexed in PubMed through Dec. 2012, with no limit on date of publication. Methodology adhered to the PRISMA guidelines. Data were systematically extracted by 2 reviewers and graded by the Venice criteria for studies of genetic associations. A metaanalysis was performed on all single nucleotide polymorphisms evaluated by 2 or more studies with similar methodology. The metaanalysis suggests that collagen type 3 alpha 1 (COL3A1) rs1800255 genotype AA is associated with pelvic organ prolapse (odds ratio, 4.79; 95% confidence interval, 1.91-11.98; P = .001) compared with the reference genotype GG in populations of Asian and Dutch women. There was little evidence of heterogeneity for rs1800255 (P value for heterogeneity = .94; proportion of variance because of heterogeneity, I(2) = 0.00%). There was insufficient evidence to determine whether other single nucleotide polymorphisms evaluated by 2 or more papers were associated with pelvic organ prolapse. An association with pelvic organ prolapse was seen in individual studies for estrogen receptor alpha (ER-α) rs2228480 GA, COL3A1 exon 31, chromosome 9q21 (heterogeneity logarithm of the odds score 3.41) as well as 6 single nucleotide polymorphisms identified by a genome-wide association study. Overall, individual studies were of small sample size and often of poor quality. Future studies would benefit from more rigorous study design as outlined in the Venice recommendations.

[Translational research in gestational diabetes mellitus and mild gestational hyperglycemia: current knowledge and our experience]

Maternal diabetes constitutes an unfavorable environment for fetal-placental and embryonic development. It is has important repercussion in modern obstetrics, since it is associated to an increased risk of neonatal and maternal morbidity, and it still is a significant medical challenge. The increased occurrence of diabetes worldwide, the increase in diabetes type 2 in women at reproductive age and the crossed generation of intrauterine programming for diabetes type 2 are the bases for the growing interest in utilization of diabetic experimental samples, with the aim to acquire knowledge about the mechanisms that induce development alterations in gestational diabetes. Several studies have shown the benefits of diabetes prevention, with interventions in lifestyle, metabolic improvement and control of cardiovascular risk factors to substantially prevent the complications of this devastating disease. Despite these findings, the recent revolution in the scientific knowledge, and the infinite number of new therapies for diabetes, there is still a large gap between what was learned through research and what is really done in public, clinical and community health. The negative economic impact of this complacency in people, families, and national economies is alarming. It is expected that translational research in the binomial diabetes and pregnancy are implemented in centers of excellence, in both basic and applied research, and complemented by multicenter clinical studies, conducted in a pragmatic way to increase the level of scientific evidence with more reliable diagnostic and propaedeutic resources.

Prevention and management of pelvic organ prolapse

Pelvic organ prolapse is a highly prevalent condition in the female population, which impairs the health-related quality of life of affected individuals. Despite the lack of robust evidence, selective modification of obstetric events or other risk factors could play a central role in the prevention of prolapse. While the value of pelvic floor muscle training as a preventive treatment remains uncertain, it has an essential role in the conservative management of prolapse. Surgical trends are currently changing due to the controversial issues surrounding the use of mesh and the increasing demand for uterine preservation. The evolution of laparoscopic and robotic surgery has increased the use of these techniques in pelvic floor surgery.

Urethral striated muscle and extracellular matrix morphological characteristics among mildly diabetic pregnant rats: translational approach

INTRODUCTION AND HYPOTHESIS

Diabetes mellitus (DM) during pregnancy is associated with high levels of urinary incontinence (UI) and pelvic floor muscle dysfunction. Mild DM can lead to changes in urethral striated muscle and extracellular matrix (ECM) in pregnant rats considering both structures as an entire system responsible for urinary continence.

METHODS

Ninety-two female Wistar rats were distributed in four experimental groups: virgin, pregnant, diabetic, and diabetic pregnant. In adult life, parental nondiabetic female rats were mated with nondiabetic male rats to obtain newborns. At the first day of birth, newborns received citrate buffer (nondiabetic group) or streptozotocin 100 mg/kg body weight, subcutaneous route (mild DM group). At day 21 of the pregnancy, the rats were lethally anesthetized and the urethra and vagina were extracted as a unit. Urethral and vaginal sections were cut and analyzed by: (a) cytochemical staining for ECM and muscle structural components, (b) immunohistochemistry to identify fast- and slow-muscle fibers, and (c) transmission electron microscopy for ultrastructural analysis of urethral striated muscle.

RESULTS

In comparison with the three control groups, variations in the urethral striated muscle and ECM from diabetic pregnant rats were observed including thinning, atrophy, fibrosis, increased area of blood vessels, mitochondria accumulation, increased lipid droplets, glycogen granules associated with colocalization of fast and slow fibers, and a steady decrease in the proportion of fast to slow fibers.

CONCLUSIONS

Mild DM and pregnancy can lead to a time-dependent disorder and tissue remodeling in which the urethral striated muscle and ECM has a fundamental function.

Expression and significance of lysyl oxidase-like 1 and fibulin-5 in the cardinal ligament tissue of patients with pelvic floor dysfunction

Pelvic organ prolapse (POP) is a disabling disorder in women characterized by a loss of pelvic floor support, leading to the herniation of the uterus into or through the vagina. POP is a complex problem that likely involves multiple mechanisms with limited therapies available, and is associated with defects in connective tissue including elastic fibers. This study was designed to investigate the expression of fibulin-5 and lysyl oxidase-like 1 (LOXL1) in the cardinal ligament in samples taken from the POP group compared to the non-POP group. Specimens were obtained during abdominal hysterectomy from the cardinal ligament of 53 women with POP and 25 age- and parity- matched women with non-POP among post-menopausal women with benign gynecologic pathology. Protein expression was evaluated using the immunohistochemical staining method. For statistical analyses, chi-square test and Spearman's correlation were used with the statistical package SPSS13.0 system. Our results showed that both fibulin-5 and LOXL1 expressions were decreased in the cardinal ligament in the POP group compared to the non-POP group (P < 0.05). The expression of fibulin-5 and LOXL1 were correlated closely with the stage of POP, accompanied by stress urinary incontinence and frequency of vaginal delivery (P < 0.05), but had no relationship with post-menopausal state (P > 0.05). The expression of fibulin-5 was positively associated with LOXL1 in POP (P < 0.05). We conclude that changes in fibulin-5 and LOXL1 expression may play a role in the development of POP.

Decreased expression of elastin, fibulin-5 and lysyl oxidase-like 1 in the uterosacral ligaments of postmenopausal women with pelvic organ prolapse

AIM

Pelvic organ prolapse is associated with defects in connective tissues, including elastic fibers. The purpose of this study was to investigate the expression of fibulin-5 and lysyl oxidase-like 1 (LOXL1), which play an essential role in the synthesis and assembly of elastic fibers, in the uterosacral ligaments of women with advanced pelvic organ prolapse (POP) compared with controls.

METHOD

Specimens were obtained prospectively during transvaginal or abdominal hysterectomy from 30 women with advanced pelvic organ prolapse and 30 controls matched to the POP group for age and parity among postmenopausal women with benign gynecologic diseases. The expressions of elastin, fibulin-5 and LOXL1 in uterosacral ligaments were measured by immunohistochemistry.

RESULTS

We detected a decreased, sometimes absent, expression of fibulin-5 and LOXL1 in the uterosacral ligaments of women with POP, despite a positive expression of elastin. There was a decrease in positive percentage of LOXL1 in the POP group (23.3%) compared with the controls (60%) (P = 0.004). With immunolabeling intensity classified as negative, weak, moderate or strong, there was a decrease in the expression of fibulin-5 in the POP group (P = 0.049). We also detected a significantly decreased expression of LOXL1 in the POP group (P = 0.001).

CONCLUSIONS

There was decreased expression of fibulin-5 and LOXL1 in the uterosacral ligaments of patients with pelvic organ prolapse, while the elastin expression was equivalent, which may suggest the possibility of defects in elastic fiber remodeling in the postpartum period and contribute to POP.

TGF-beta 1 is a potential regulator of vaginal tropoelastin production

INTRODUCTION AND HYPOTHESIS

Our aims were to correlate transforming growth factor (TGF)-β1 and elastin mRNA expression in the vagina of women and to measure the effects of TGF-β1 on vaginal smooth muscle cell (SMC) proliferation and tropoelastin production.

METHODS

Vaginal walls were sampled in women (n = 20). TGF-β1 and elastin mRNA expression was assessed by RT-PCR. SMC cultures were performed from vaginal wall biopsies. SMC were incubated with TGF-β1, and cell proliferation was assessed by MTT-assay. Tropoelastin production was measured by the Fastin Elastin Assay.

RESULTS

There was a significant positive correlation between TGF-β1 and elastin mRNA (r = 0.784, P < 0.01). SMC proliferation was significantly increased by 10 ng/mL TGF-β1 [relative cell number, mean ± SD, 198% ± 32% of control (P = 0.01)]. Tropoelastin production was significantly increased by TGF-β1 [mean ± SD, 645% ± 180% of control (P = 0.01)].

CONCLUSIONS

There is a positive correlation between TGF-β1 and elastin mRNA expression in the vaginal wall. In vitro, TGF-β1 increases vaginal tropoelastin production in vaginal SMC.

The effect of raloxifene, a SERM, on extracellular matrix protein expression of pelvic fibroblasts

INTRODUCTION AND HYPOTHESIS

We hypothesize that the abnormal extracellular matrix (ECM) turnover in pelvic tissues of women with prolapse may be attenuated by raloxifene. We examine the effect of raloxifene on ECM protein expression in pelvic fibroblasts.

METHODS

Pelvic fibroblasts were isolated from cases (N = 6) and controls (N = 3). Cells were treated with raloxifene. Dose-response analyses were performed by ANOVA. mRNA and protein expression of collagen I, III, MMPs, and TIMPs were determined by RT-PCR and Western blot. MMP activity was analyzed by zymography.

RESULTS

The mRNA expression of TIMP-3 and protein expression of TIMP-1 and TIMP-3 were significantly increased by raloxifene in fibroblasts from both cases and controls (P < 0.05). Collagen I, III, and MMP mRNA and protein expressions were not affected.

CONCLUSIONS

Raloxifene selectively attenuates abnormal matrix degradation by increasing inhibitors of proteases, TIMPs, in pelvic fibroblasts. This opens the possibility for SERMs to be used as preventive therapy for pelvic floor disorders.

Expression of Bone Morphogenetic Protein-1 in vaginal tissue of women with severe pelvic organ prolapse

OBJECTIVES

To analyze the differential gene and protein expression of Bone Morphogenetic Protein-1 in vaginal tissue of women with advanced pelvic organ prolapse and controls.

STUDY DESIGN

We sampled the anterior vaginal wall of 39 premenopausal (23 patients and 16 controls), and 18 postmenopausal women (13 patients and 5 controls) during hysterectomy. Total mRNAs and proteins were quantified by real-time RT-PCR and immunoblotting.

RESULTS

Bone Morphogenetic Protein-1 gene expression was decreased in pre- and postmenopausal pelvic organ prolapse patients compared with asymptomatic women (P = .01). The expression of 130 kDa, 92.5 kDa, and 82.5 kDa isoforms of Bone Morphogenetic Protein-1 were down-regulated in postmenopausal patients (P = .01), whereas the 130 kDa isoform expression was up-regulated in premenopausal patients (P = .009), when compared with respective controls.

CONCLUSION

The Bone Morphogenetic Protein-1 expression in human vagina was altered in patients with severe pelvic organ prolapse and influenced by menopausal status. Dysregulation of Bone Morphogenetic Protein-1 may contribute for a deficient vaginal connective tissue and support.

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.

Polymorphism of a COLIA1 gene Sp1 binding site in Korean women with pelvic organ prolapse

PURPOSE

To evaluate the possible influence of G-->T substitution at the Sp1-binding site of the COLIA1 gene on the risk of pelvic organ prolapse (POP).

MATERIALS AND METHODS

The study group consisted of 15 women with advanced stage POP. Fifteen control subjects with uterine myomas among the postmenopausal women were matched for age and parity. DNA was obtained from peripheral blood leukocytes. The fragments of the first intron of the COLIA1 gene were amplified by real time polymerase chain reaction. The polymorphism was identified using LightCycler Technology with hybridization probes. Sequencing reactions were performed on each template using commercial primer.

RESULTS

Two groups had no significant difference in medical history, surgical, and smoking history. The homozygous peaks in two groups were noted at 57 on melting curve analysis. Sequencing reactions confirmed the G/G alleles in the 30 specimens tested. We could not find any polymorphism at the Sp1-binding site in COLIA1 gene with advanced stage POP. Statistical significance was considered to be p < .05.

CONCLUSION

The polymorphism of the Sp1-binding site in the COLIA1 gene did not contribute to the development of POP in Korea.

Changes in expression of fibulin-5 and lysyl oxidase-like 1 associated with pelvic organ prolapse

OBJECTIVES

Pelvic organ prolapse is associated with defects in connective tissue including elastic fibers. The purpose of this study was to investigate expression of fibulin-5 and lysyl oxidase-like 1, which play an essential role in synthesis and assembly of elastic fibers in the uterosacral ligament, in samples taken from women with advanced pelvic organ prolapse compared with controls.

STUDY DESIGN

Specimens were obtained prospectively during abdominal hysterectomy from 30 women with advanced pelvic organ prolapse and 30 controls matched to the study group for age and parity among postmenopausal women with benign gynecologic pathology. Expression levels of protein and mRNA of fibulin-5 and lysyl oxidase-like 1 in uterosacral ligaments were measured by Western blot analysis and real-time quantitative polymerase chain reactions. For statistical analyses, Student's t-test, chi-square test, Mann-Whitney U test, Fisher's exact test and Spearman's correlation were used.

RESULTS

Significant decrease in the expression of mRNA of fibulin-5 was found in patients with prolapse (P-value=0.042; 0.743+/-0.229 and 1.061+/-0.537). The expression of mRNA of lysyl oxidase-like 1 was increased in the patient group (P-value=0.017; 4.099+/-2.832 and 1.816+/-1.602). Similar results were shown in Western blot analysis. Differences in expression of fibulin-5 and lysyl oxidase-like 1 were noted according to stage of prolapse (P-value=0.037 and 0.009).

CONCLUSIONS

There was decreased expression of fibulin-5 and increased expression of lysyl oxidase-like 1 in uterosacral ligaments in patients with pelvic organ prolapse, which suggests the possibility of defects in elastin synthesis.

Experimental comparison of abdominal wall repair using different methods of enhancement by small intestinal submucosa graft

INTRODUCTION AND HYPOTHESIS

To assess the biomechanical properties of full-thickness abdominal wall defects, either using Native tissues, with or without Overlay, and by substitution of the Defect by small intestinal submucosa mesh.

METHODS

Seventy-two rats were divided into three groups according to repair method (Native, Overlay or Defect). At 7, 14, 30, and 90 days, six rats were sacrificed to measure tensile strength, collagen ingrowth, and host response.

RESULTS

Explants had comparable strength at 30 days, the majority rupturing at the interface. Afterwards, the Native group was more resistant than both small intestine submucosa (SIS) groups with a more organized fibrotic scar on histology at 90 days.

CONCLUSIONS

SIS augmentation of native tissue repair does not increase strength. Replacement of abdominal wall by SIS is equally strong when compared to the SIS-augmented group; however, materials preferably rupture at the site of the implant itself.

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.

Inherited pelvic organ prolapse in the mouse: preliminary evaluation of a new murine model

The objective of this study was to report the initial anatomic, radiographic, and genetic evaluations of a novel form of spontaneous pelvic organ prolapse (S-POP) in mice. We observed S-POP in a colony of UPII-SV40T transgenic mice developed for studies on bladder cancer. We utilized magnetic resonance imaging and necropsy to characterize this finding. We have established a breeding colony to identify inheritance patterns and for future studies. Selective breeding isolated the S-POP phenotype from the transgene. In contrast to other animal models, the S-POP mouse does not require an obligatory antecedent event to manifest pelvic organ prolapse. Necropsy and imaging demonstrate significant displacement of the pelvic organs distal to the pelvic floor in both sexes. The appearance of the POP is similar to that seen in the human female phenotype. Preliminary breeding studies indicate an autosomal dominant inheritance pattern. This mouse may be an effective animal model for the study of POP in humans.

Translational research: from benchside to bedside

Translation of the achievements of basic science into everyday clinical practice remains a major issue in contemporary medicine, and is addressed through a new discipline, translational research, which aims to bridge the gap between basic and clinical research. Translational research encompasses laboratory studies, clinical demands, public health and health management, policies and economics; it is crucial in the evolution of contemporary biomedical science; and its interventions follow the political-economic, ethical-social and educational-scientific approaches. Translational research can progress through reorganisation of academic teams in a translational way. New academic posts translationally orientated are urgently needed, particularly in the field of trauma medicine, where lack of awareness of this new evolution is evident.

The integrated continence system: a manual therapy approach to the treatment of stress urinary incontinence

Stress urinary incontinence (SUI) constitutes a large-scale public health concern. The integrated continence system (ICS) developed by the authors is an evidence-based model that demonstrates how urinary incontinence is maintained through the interaction of three structural systems (intrinsic urethral closure, urethral support and lumbopelvic stability) and three modifiable factors (motor control, musculoskeletal and behavioural). The purpose of the ICS is first, to demonstrate the important role that manual physiotherapists can play in the treatment of SUI and second, to guide clinical practice decisions in order to improve clinical outcomes among women with SUI.

Elastin expression and elastic fibre width in the anterior vaginal wall of postmenopausal women with and without prolapse

OBJECTIVES

To compare elastin expression and elastic fibre width in the anterior vaginal wall of postmenopausal women with and with no bladder prolapse.

PATIENTS AND METHODS

Full-thickness specimens were obtained from the upper lateral anterior vaginal wall of women having a large cystocele repaired (stage III or IV; prolapse group, 33) and the same location in patients with no prolapse having radical cystectomy (control group, 10). The percentage of elastin-positive tissue and elastic fibre width were measured by immunohistochemistry on 6 microm thick tissue sections from 10 random field readings per sample using image analysis software. The examiner was unaware of sample identity and the patients' clinical history.

RESULTS

The age was comparable between the control and prolapse groups (median 70.5 years), and the parity, vaginal deliveries, hormone replacement use, cigarette smokers and body mass index were no different between the groups. Immunohistochemical staining and morphometric analysis indicated that elastin expression in the prolapse group was 10.6%, vs 14.4% in the control group (P = 0.049). The median width of elastic fibres was 0.9 microm in the prolapse and 1.8 microm in the control groups (P < 0.001). Elastin expression and elastic fibre width appeared to be stable with increasing age in the prolapse group.

CONCLUSIONS

In this case-control study investigating elastin changes in postmenopausal women with prolapse, the elastin expression and fibre width were significantly lower in the vaginal wall of patients with a large cystocele than in controls of a similar age.

Pelvic organ prolapse in fibulin-5 knockout mice: pregnancy-induced changes in elastic fiber homeostasis in mouse vagina

Pelvic organ prolapse is strongly associated with a history of vaginal delivery. The mechanisms by which pregnancy and parturition lead to failure of pelvic organ support, however, are not known. Recently, it was reported that mice with null mutations in lysyl oxidase-like 1 (LOXL1) develop pelvic organ prolapse. Elastin is a substrate for lysyl oxidase (LOX) and LOXL1, and LOXL1 interacts with fibulin-5 (FBLN5). Therefore, to clarify the potential role of elastic fiber assembly in the pathogenesis of pelvic organ prolapse, pelvic organ support was characterized in Fbln5-/- mice, and changes in elastic fiber homeostasis in the mouse vagina during pregnancy and parturition were determined. Pelvic organ prolapse in Fbln5-/- mice was remarkably similar to that in primates. The temporal relationship between LOX mRNA and protein, processing of LOXL1 protein, FBLN5 and tropoelastin protein, and desmosine content in the vagina suggest that a burst of elastic fiber assembly and cross linking occurs in the vaginal wall postpartum. Together with the phenotype of Fbln5-/- mice, the results suggest that synthesis and assembly of elastic fibers are crucial for recovery of pelvic organ support after vaginal delivery and that disordered elastic fiber homeostasis is a primary event in the pathogenesis of pelvic organ prolapse in mice.

Does water delivery affect pelvic floor? Ultrasound evaluation of perineal function

OBJECTIVE

The aim of the study is to analyse urethral mobility and excursion of the pubo-rectal angle, using perineal ultrasound, after normal vaginal delivery and water delivery.

MATERIALS AND METHODS

A total of 52 primiparous women were enrolled: 25 who had delivery in water (W Group), 27 who had delivery without using water (NW Group). Every woman underwent perineal ultrasound assessment at 6 months after having given birth. The following parameters were assessed: urethral mobility during Valsalva's manoeuvre, movement of the puborectal sling angle during contraction of the levator ani muscle.

RESULTS

Data obtained show that the urethral mobility during Valsalva's manoeuvre is higher in the W Group (34.9 degrees) in comparison to the NW Group (29.5 degrees), without statistically significant differences. The excursion of the pubo-rectal sling angle resulted lower in the W Group (8.7 degrees) than in the NW Group (11.0 degrees), without statistically significant differences.

CONCLUSION

The present study found no statistically differences in pelvic floor, using perineal ultrasound, between water and "non-water" delivery.

The biology behind fascial defects and the use of implants in pelvic organ prolapse repair

Implant materials are increasingly being used in an effort to reduce recurrence after prolapse repair with native tissues. Surgeons should be aware of the biology behind both the disease as well as the host response to various implants. We will discuss insights into the biology behind hernia and abdominal fascial defects. Those lessons from "herniology" will, wherever possible, be applied to pelvic organ prolapse (POP) problems. Then we will deal with available animal models, for both the underlying disease and surgical repair. Then we will go over the features of implants and describe how the host responds to implantation. Methodology of such experiments will be briefly explained for the clinician not involved in experimentation. As we discuss the different materials available on the market, we will summarize some results of recent experiments by our group.

Sequence variant in the laminin gamma1 (LAMC1) gene associated with familial pelvic organ prolapse

Pelvic organ prolapse is a common condition, affecting up to a third of women throughout their lifetime. Genetic factors are believed to account for about 30% of the incidence, and are the least understood component of the disorder. Familial cases, particularly those in which prolapse manifests in young women, are especially valuable in the effort to find the genes involved. We recently reported autosomal dominant transmission as the most likely mode of inheritance, based on a collection of families with high incidence of prolapse. Of greatest interest was a family in which three generations of female relatives suffered from prolapse at a very young age. A genome-wide linkage scan performed using the Affymetrix GeneChip Human mapping 10K array identified ten regions with a LOD score of 1.5, the maximum possible for this family. Candidate genes within those regions were analyzed for expression in vaginal tissue by RT-PCR. Of the genes confirmed to be expressed, LAMC1 was further evaluated by sequencing and select single nucleotide polymorphism (SNP) genotyping for causative sequence variants in affected family members. We identified one such SNP, rs10911193. The rare T variant segregating with the condition is present at a frequency of 4.9% in the general population and 22% among probands from our cohort of families. It affects the binding site for NFIL3, a transcription factor that we verified to be co-expressed in vaginal tissue. Altogether these data suggest that a polymorphism in the promoter of LAMC1 may increase the susceptibility to early-onset pelvic organ prolapse.

Failure of elastic fiber homeostasis leads to pelvic floor disorders

Pelvic floor disorders, a group of conditions affecting adult women, include pelvic organ prolapse and urinary incontinence. Vaginal childbirth and aging are risk factors, and weakening of the pelvic support structures is a major aspect of the pathology. However, the underlying molecular mechanism remains unknown. Female reproductive organs are rich in elastic fibers that turn over slowly in most adult tissues but undergo massive remodeling in the reproductive organs through pregnancy and birth. Here we show that a failure to maintain elastic fiber homeostasis in mice causes pelvic floor disorders. Lysyl oxidase-like-1 (LOXL1), a protein essential for the postnatal deposition of elastic fibers, was highly expressed and regulated in the reproductive tract of the mouse, and its expression was diminished during aging. LOXL1 deficiency caused an inability of reproductive tissues to replenish elastic fibers after parturition, leading to pelvic organ prolapse, weakening of the vaginal wall, paraurethral pathology, and lower urinary tract dysfunction. These data demonstrate the importance of elastic fibers for maintaining structural and functional integrity of the female pelvic floor. Our findings raise the possibility that a failure of elastic fiber homeostasis, either due to genetic predisposition or advancing age, could underlie the etiology of pelvic floor dysfunction in women.

Extracellular matrix integrity: a possible mechanism for differential clinical effects among selective estrogen receptor modulators and estrogens?

Recent gene microarray studies have illustrated heterogeneity in gene expression changes not only between estrogens and selective estrogen receptor modulators (SERMs), but also across different SERM molecules. In ovariectomized rats, this phenomenon was observed with respect to a number of genes involved in collagen turnover and extracellular matrix (ECM) integrity in the uterus and vaginal tissues. Preliminary mechanistic data suggest that these effects on ECM integrity may have relevance in the context of the effect of estrogens and some SERMs to increase the risk of pelvic organ prolapse and the incidence of urinary incontinence in postmenopausal women. Given the pivotal role of ECM integrity and collagen turnover in other tissues and disease states, these processes may provide a fruitful target for future research into the mechanisms for the heterogeneous pharmacology of estrogens and SERMs across different cell types and target tissues.

Familial transmission of genitovaginal prolapse

Some females with little to no risk factors develop prolapse, while other females with multiple risk factors do not. It appears that some women may have a predisposition for prolapse in the setting of equivalent risk factors. We identified 10 patients younger than 55 years old with a family history of prolapse. Their average age was 37 years (range 27-51), the mean number of deliveries was 1.8, and their mean birth weight was 8 lbs. Genetic analysis of the inheritance pattern within these families demonstrated that pelvic organ prolapse segregated in a dominant fashion with incomplete penetrance in these families. Both maternal and paternal transmissions were observed. The relative risk to siblings of affected patients was five times that of the risk for the general population. Further investigation of these families may identify a genetic defect responsible for prolapse.