Changes of glycoprotein and collagen immunolocalization in the uterine artery wall of postmenopausal women with and without pelvic organ prolapse

The role of tenascin-X in the uterosacral ligaments of postmenopausal women with pelvic organ prolapse: an immunohistochemical study

INTRODUCTION AND HYPOTHESIS

Abnormalities of connective tissue structure or its repair mechanism may predispose women to pelvic organ prolapse (POP). We hypothesized that the expression of tenascin-X in the uterosacral ligament of postmenopausal women with symptomatic POP is increased compared with postmenopausal women without POP. Furthermore, we identified clinical risk factors associated with POP in our study population.

METHODS

We conducted a retrospective case-control study in which 33 postmenopausal women with symptomatic POP ≥ pelvic organ prolapse quantification system (POP-Q) stage II were matched with 33 postmenopausal women without POP. Studied tissue specimens were taken from hysterectomy specimens, and tenascin-X expression was investigated by immunohistochemistry. The immunohistochemical profile of the uterosacral connective tissue of cases and controls was compared.

RESULTS

Tenascin-X was expressed in 94% of POP cases and in 91% of controls. Our study failed to show any statistically significant differences in tenascin-X expression between women with and without POP (p = 0.64). However, tenascin-X was significantly more expressed in cases with severe prolapse (POP-Q stage IV) compared with moderate prolapse stages (POP-Q stage II and III) (p = 0.001). Advanced patient age as well as early menopausal age remained independent risk factors associated with POP in multiple logistic regression analysis (p = 0.001).

CONCLUSION

No difference could be demonstrated between tenascin-X expression in patients with or without POP. Tenascin-X does not seem to play a major role in the pathogenesis of POP in postmenopausal women.

Oxidative status of cardinal ligament in pelvic organ prolapse

Pelvic organ prolapse (POP) is a common and distressing health problem in adult women, but the pathophysiological mechanism is yet to be fully elucidated. Previous studies have indicated that oxidative stress may be associated with POP. Thus, the aim of the present study was to investigate the oxidative status of pelvic supportive tissue in POP and further demonstrate that oxidative stress is associated with the pathogenesis of POP. A total of 60 samples were collected from females undergoing hysterectomy for POP or cervical intraepithelial neoplasia (CIN). This included 16 females with POP II, 24 females with POP III–IV (according to the POP-Q system) and 20 females with CIN II–III as the control group. Immunohistochemistry was utilized to measure the expression of oxidative biomarkers, 8-hydroxydeoxyguanosine (8-OHdG) and 4-hydroxynonenal (4-HNE). Major antioxidative enzymes, mitochondrial superoxide dismutase (MnSOD) and glutathione peroxidase 1 (GPx1) were measured through reverse transcription-quantitative polymerase chain reaction, western blotting and enzyme activity assays. The results demonstrated that in the cardinal ligament, the expression of 8-OHdG and 4-HNE was higher in the POP III–IV group compared with the POP II group and control group. The MnSOD and GPx1 protein level and enzyme activity were lower in the POP III–IV group compared with the POP II or the control group, while the mRNA expression level of MnSOD and GPx1 was increased. In conclusion, oxidative damage is increased in the pelvic supportive ligament of female patients with POP and the antioxidative defense capacity is decreased. These results support previous findings that oxidative stress is involved in the pathogenesis of POP.

Effect of puerarin on collagen metabolism of fibroblasts in pelvic tissue of women with pelvic organ prolapse

The aim of the present study was to investigate the protective effect of puerarin on pelvic organ prolapse (POP) and the underlying mechanisms that regulate the metabolism of human parametrial ligament fibroblasts (HPLFs). HPLFs obtained from the pelvic tissue of patients with (n=10) or without (n=8) POP during hysterectomy were isolated by enzymatic digestion and subsequently identified by immunocytochemistry in a previous study of the authors. Following this, cultured HPLFs were treated with 0.01, 0.10 or 1.00 mmol/l puerarin, followed by detection of proliferation rate by Cell Counting kit‑8 assay. Following incubation with puerarin for 48 h, mRNA and protein expression levels of tissue inhibitor of metalloproteinase‑1 (TIMP‑1), matrix metalloproteinase (MMP)‑2 and ‑9, and collagen (COL)I and III in HPLFs were quantified by reverse transcription‑quantitative polymerase chain reaction, and western blot and gelatin zymography analyses, respectively. MMP‑2 and ‑9 expression levels were increased, whereas expression levels of TIMP‑1, and COL I and III were decreased, in patients with POP compared with healthy controls. Following puerarin treatment, the expression levels of TIMP‑1, and COL I and III were enhanced, whereas MMP‑2 and ‑9 were inhibited. In conclusion, the present study demonstrated evidence increased degradation of the extracellular matrix in pelvic tissues of patients with POP compared with controls, and the protective effect of puerarin against POP via its anti‑degradation effect on collagen. These results provide evidence for puerarin as a novel approach for the treatment of POP.

Association of matrix metalloproteinase-10 polymorphisms with susceptibility to pelvic organ prolapse

AIM

The aim of this study was to explore the correlation between genetic mutations in matrix metalloproteinase-10 (MMP-10) and susceptibility to pelvic organ prolapse (POP).

MATERIAL AND METHODS

From September 2011 to December 2013, 263 subjects were recruited, including 91 patients with POP (case group) and 172 non-POP patients (control group). Total MMP-10 concentrations in serum were measured by enzyme-linked immunosorbent assay. The genotyping of MMP-10 was achieved by quantitative real-time polymerase chain reaction. All data were analyzed with SPSS 18.0.

RESULTS

We found that parity, menopause, history of total hysterectomy, and family history of POP were all significantly higher in the POP group than in the control group (P = 0.017, P = 0.046, P = 0.0029 and P < 0.001, respectively). Serum MMP-10 levels were obviously higher in the POP group than in the control group (P < 0.05). In addition, there was a statistically significant difference between the two groups in the distribution frequency of the MMP-10 (rs17435959G/C) genotype (P < 0.05). However, the distribution frequency of the MMP-10 (rs17293607C/T) genotype between the two groups showed no significant differences (P > 0.05). Furthermore, the patients with parity > 2 and postmenopausal women had elevated serum MMP-10 levels, and the patients with parity > 2 and postmenopausal women who carried the G/C + C/C genotype in the MMP-10 gene had an increased risk of POP.

CONCLUSION

We support the view that the rs17435959 polymorphism of the MMP-10 gene may be associated with an increased risk of POP.

HOXA11 and MMP2 gene expression in uterosacral ligaments of women with pelvic organ prolapse

OBJECTIVE

Pelvic organ prolapse (POP) is a common disorder that negatively impacts the quality of life in many women. Uterosacral ligaments (USLs) are supportive structures of the pelvic organs that are often attenuated in women with POP. The HOXA genes regulate the development of the uterosacral ligaments. We compared expression of HOXA11 and MMP2 in USLs of women with and without POP.

MATERIAL AND METHODS

A prospective sequential cross sectional study was conducted in ZTB Women's Health Research and Education Hospital. We compared expression of HOXA11 and MMP2 in USLs of women with (n:18) and without (n: 15) POP. Total RNA was isolated from patient (n:18) and control (n:15) uterosacral ligament tissues with TriPure isolation reagent according to the manufacturer's instructions. Expression levels of HOXA11 and MMP2 were determined using semiquantitative RT-PCR in a Light Cycler 480 system. Real-time ready catalog assays, which are short FAM-labeled hydrolysis probes containing locked nucleic acid, were used for RT-PCR reactions.

RESULTS

There was no difference in patients' mean age, parity, body mass indexes, and menopausal status between two groups. Means of RNA expression of MMP2 were 1.27±0.6 and 0.75±0.4 in the POP group vs control group, respectively (p:0.007). Means of RNA expression of HOXA 11 were 2.57±2.4 and 1.94±1.4 in the POP group vs control group, respectively (p:0.376). The POP group was divided as mild and severe POP; there was no difference in HOXA11 and MMP2 RNA expression between groups (p>0.05).

CONCLUSION

Although there was no difference HOXA11 RNA expression in USLs with the POP group vs control, there was a significant difference MMP2 RNA expression in USLs with the POP group vs control. There are limited studies on this subject, and study results are contradictory. Further investigations with larger numbers of cases are needed to clarify this subject.

Association between pelvic organ prolapse and stress urinary incontinence with collagen

The aim of the present study was to investigate the ultrastructure and content of collagen in uterosacral ligaments and paraurethral tissues in patients with pelvic organ prolapse (POP) and stress urinary incontinence (SUI), analyzing the association between POP and collagen dysfunction. The study comprised three groups: Control, POP and POP with SUI (n=30 per group). Histological characteristics of collagen fiber were observed and the diameters were measured using light and electron microscopy to determine the Type I and Type III collagen content of the main ligament in the urethral specimens. In the POP and POP with SUI groups, observations included diffuse atrophy of smooth muscles, active fibroblast metabolism, swollen mitochondria and visible Golgi apparatus. The collagen fibril diameters in the cardinal ligaments, uterosacral ligaments and paraurethral tissues were significantly greater in the POP and POP with SUI groups compared with those in the control group (P<0.01). In addition, the expression levels of Type I and Type III collagen were significantly lower in the POP and POP with SUI groups when compared with the control group (P<0.01). In the POP with SUI group, pelvic tissues were frail, resulting in smooth muscle bundles comminuting and arranging in a disorganized pattern. Fibroblast and myoblast metabolisms were active and new microvascular cells were weak. However, the collagen fibril diameter increased. Thus, collagen and ultrastructural changes in the pelvic floor may be associated with the development of POP and SUI.

Vaginal childbirth and pelvic floor disorders

Childbirth is an important event in a woman's life. Vaginal childbirth is the most common mode of delivery and it has been associated with increased incidence of pelvic floor disorders later in life. In this article, the authors review and summarize current literature associating pelvic floor disorders with vaginal childbirth. Stress urinary incontinence and pelvic organ prolapse are strongly associated with vaginal childbirth and parity. The exact mechanism of injury associating vaginal delivery with pelvic floor disorders is not known, but is likely multifactorial, potentially including mechanical and neurovascular injury to the pelvic floor. Observational studies have identified certain obstetrical exposures as risk factors for pelvic floor disorders. These factors often coexist in clusters; hence, the isolated effect of these variables on the pelvic floor is difficult to study.

Pelvic floor disorders following vaginal or cesarean delivery

PURPOSE OF REVIEW

Pelvic floor disorders affect women of all ages and are associated with significant economic burden and poor quality of life. Current literature suggests an association between childbirth and these disorders. In this review, we summarize recent advancements in our understanding of this association.

RECENT FINDINGS

Vaginal childbirth appears to be strongly associated with stress urinary incontinence and pelvic organ prolapse. There is less evidence to suggest an association between vaginal delivery and overactive bladder symptoms. History of more than one perineal laceration increases the likelihood of developing prolapse. Similar association has not been established for episiotomy. Disruption or denervation of structural components of pelvic floor support system, particularly levator ani muscle complex, is associated with later development of pelvic floor disorders. Imbalance in homeostasis of connective tissue remodeling of the vaginal wall from overstretching during childbirth is another possible mechanism.

SUMMARY

Pelvic floor disorders represent a significant health problem affecting women of all ages. Identification of potential modifiable risk factors and advancement in understanding of the underlying pathophysiology is crucial for primary and secondary prevention of these disorders and for improvement in treatment strategies.

Genetics of pelvic organ prolapse: crossing the bridge between bench and bedside in urogynecologic research

An increasing number of scientists have studied the molecular and biochemical basis of pelvic organ prolapse (POP). The extracellular matrix content of the pelvic floor is the major focus of those investigations and pointed for potential molecular markers of the dysfunction. The identification of women predisposed to develop POP would help in the patients' management and care. This article includes a critical analysis of the literature up to now; discusses implications for future research and the role of the genetics in POP.