A randomized controlled study of the efficacy of misoprostol and hyaluronic acid in preventing adhesion formation after gynecological surgery: a rat uterine horn model

Short-term reproductive outcomes analysis and prediction of the modified uterine stent treatment for mild to moderate intrauterine adhesions: experience at a single institution

BACKGROUND

To evaluate the efficacy of modified uterine stent in the treatment of mild-to-moderate intrauterine adhesions and explore the relative indicators affecting prognosis prediction.

METHODS

A total of 115 patients with mild-to-moderate intrauterine adhesions received a modified uterine stent placement after hysteroscopy adhesiolysis. The second-look hysteroscopy operated after 3 months surgery, and the third-look hysteroscopy operated after 6 months surgery if necessary. The stent was removed when the cavity shape was repaired, then the reproductive outcomes were followed up one year.

RESULTS

Menstrual blood volume, endometrial thickness and volume had increased significantly after 3 months surgery. The rates of cavity repaired were 86.96% (100/115) after 3 months surgery and 100% (115/115) after 6 months surgery cumulatively. Endometrial thickness after 3-months surgery was positively associated with uterine cavity shape repaired (P<0.01). The receive operating characteristic (ROC) curve showed the rate of uterine cavity shape repaired predicted by the model was 0.92, based on the endometrial thickness after 3-months surgery. The rate of pregnancy was 86.09% (99/115) in one year, while the rate of miscarriage accounted for 26.26% (26/99). The median time interval between stent removal and subsequent conception was 3 months. It showed adhesion recurrence was the risk factor for subsequent pregnancy (P<0.01).

CONCLUSIONS

A modified uterine stent placement under hysteroscopy was an effective approach for mild-to-moderate intrauterine adhesions, which is easy to operate and worthy for clinical promotion. Endometrial thickness measured by ultrasonography probably has predictive value in adhesion recurrence and subsequent pregnancy.

TRIAL REGISTRATION

ChiCTR2100051524. Date of registration (retrospectively registered): 26/09/2021.

Smart hydrogels delivered by high pressure aerosolization can prevent peritoneal adhesions

Postoperative peritoneal adhesions occur in the majority of patients undergoing intra-abdominal surgery and are one of the leading causes of hospital re-admission. There is an unmet clinical need for effective anti-adhesive biomaterials, which can be applied evenly across the damaged tissues. We examined three different responsive hydrogel types, i.e. a thermosensitive PLGA-PEG-PLGA, a pH responsive UPy-PEG and a shear-thinning hexapeptide for this purpose. More specifically, their potential to be homogeneously distributed in the peritoneal cavity by high pressure nebulization and prevent peritoneal adhesions was evaluated. Solutions of each polymer type could be successfully nebulized while retaining their responsive gelation behavior in vitro and in vivo. Furthermore, none of the polymers caused in vitro toxicity on SKOV3-IP2 cells. Following intraperitoneal administration, both the PLGA-PEG-PLGA and the hexapeptide hydrogels resulted in local inflammation and fibrosis and failed in preventing peritoneal adhesions 7 days after adhesion induction. In contrast, the pH sensitive UPy-PEG formulation was well tolerated and could significantly reduce the formation of peritoneal adhesions, even outperforming the commercially available Hyalobarrier® as positive control. To conclude, local nebulization of the bioresponsive UPy-PEG hydrogel can be considered as a promising approach to prevent postsurgical peritoneal adhesions.

Animal models in intrauterine adhesion research

Intrauterine adhesion (IUA) is a gynaecological disease caused by uterine cavity surgeries and infections that leads to partial or total occlusion of the uterine cavity. However, the underlying mechanism(s) and progression of the disease have not yet been identified. IUA has a high recurrence rate and poor prognosis, and effective drugs to prevent adhesion are lacking. Therefore, establishing an effective animal model of IUA is of great significance for revealing the pathogenesis of IUA and the mechanism(s) governing drug effects. Rats, mice, rabbits, and other animals are currently used to establish intrauterine adhesion models. The IUA induction methods include chemical, thermal, or mechanical damage and mechanical damage combined with an infective method. We analysed the advantages and disadvantages of various models and their clinical simulations in order to provide a precise animal model for exploring the pathogenesis, treatment strategies, and prevention of IUA.

Local renin-angiotensin system molecular mechanisms in intrauterine adhesions formation following gynecological operations, new strategy for novel treatment

It has recently been proposed that local tissue renin-angiotensin system activation has a role in post-surgical adhesion. Intrauterine adhesions are scar tissues that form in the endometrial cavity causing the walls of the uterine to adhere together. Women, undergoing major gynecological surgery, are exposed to a high risk of adhesion formation. Post-operative uterine adhesion is associated with chronic pain and infertility that are important problems following post-operation uterine adhesion. A local renin-angiotensin system has been found in the organs of the female reproductive system, for example in the endometrium. Data about the physiological roles of local RAS in the gynecological tract are largely unknown, but dysfunctional local RAS in the endometrium may contribute to this pathological condition. Local AngII/AT1R may be over-activated after surgical injury or hypoxia leading to an up-regulation of the molecular mechanisms that may lead to a chronic immune response, oxidative stress, and increase the expression of fibrotic molecules like TGF-β to induce the risk of connective fibrotic tissues. Based on AngII/AT1R pathological potential to induce pelvic and uterine adhesions, using angiotensin receptor blockers could be a therapeutic strategy for the prevention and treatment of post-surgical adhesions.IMPACT STATEMENTWhat is already known on this subject? Intrauterine adhesions are described as fibrotic scar tissues following gynecological surgeries. It's reported that 55-100% of women are at risk of intrauterine adhesion after gynecological surgeries. Injury to tissues and hypoxia during the surgery, promote molecular mechanisms to contribute post-surgical adhesion. Recently evidence supports the existence of renin-angiotensin system components in the gynecological tract. Abnormal expression of local angiotensin II and AT1R in uterus tissue following gynecological surgeries up-regulate molecular mechanisms to induce post-operative adhesions.What do the results of this study add? Recently there has been an increased focus on the role of the local renin-angiotensin system in organ fibrosis. The results of this Mini-review article refer to the pathological roles of the local renin-angiotensin system in fibrotic bands formation after gynecological operations. Over-activation of local renin-angiotensin systems up-regulate molecular mechanisms such as inflammation and the TGF-β1 signalling pathway. TGF-β as a profibrotic molecule strongly induces the expression of some fibrotic molecules such as PAI and TIMP to increase the risk of intrauterine adhesions.What are the implications of these findings for clinical practice and/or further research? According to the biological roles of local renin-angiotensin system and AT1R following injuries to develop post-operative adhesion, the administration of ARBs may be considered as a new therapeutic strategy for the prevention of IUA.

Establishment and comparison of different intrauterine adhesion modelling procedures in rats

Intrauterine adhesion (IUA) is caused by endometrial damage and leads to the formation of scar fibrosis and repair disorders. We compared four different rat IUA modelling procedures in order to establish a stable animal model suitable for investigating IUA. Twenty female Sprague--Dawley rats were randomly divided into four groups. IUA was induced on one side of each rat uterus by ethanol instillation, heat stripping, mechanical injury or mechanical injury with infection (dual-injury); the other side of the uterus was left intact as a control. After 8 days the rats were sacrificed, their uteri were examined for histomorphology and expression of endometrial markers was checked using immunohistochemistry. All four IUA modelling procedures resulted in visual pathophysiological changes in the rat uterus, including stenosis, congestion and loss of elasticity. Endometrial thinning, shrinkage of glands and formation of fibrotic hyperplasia were also observed. All four procedures resulted in the downregulation of cytokeratin 18 and vimentin expression compared with control tissues, as well as the upregulation of collagen I expression. After mechanical injury and dual-injury the expression of interleukin 6 was significantly increased. Overall, our results suggest that ethanol instillation is the most stable IUA modelling procedure. Mechanical injury reliably yielded inflammatory indicators.

Effects of quercetin and surgicel for preventing adhesions after gynecological surgery: A rat uterine horn model

AIM

Postoperative pelvic adhesions are significant health care problems causing chronic pelvic pain, infertility and intestinal obstruction after abdominal or pelvic surgery. We investigated the effects of quercetin and Surgicel for the prevention of adhesions after gynecological surgery.

METHODS

A double blind, randomized, controlled experimental study was designed. Forty female Wistar Hannover rats were divided into five groups: control, sham operated, quercetin, Surgicel, and quercetin + Surgicel. The control group received medication used for the surgical procedure only. The sham group received a laparotomy only. The quercetin group received 15 mg/kg quercetin in addition to undergoing the standard surgical procedure, and the injuries in the surgical group were covered with a single, 1 cm² layer of Surgicel (oxidized regenerated cellulose). The quercetin + Surgicel group received both 15 mg/kg quercetin and a single, 1 cm² layer of Surgicel. Adhesions were scored 14 days after the first surgical procedure.

RESULTS

The extent, severity, degree, total adhesion, inflammation and fibrosis scores of the control group were significantly higher than those of the quercetin, Surgicel, and quercetin + Surgicel groups. There was no significant difference between the Surgicel and quercetin groups in degree, but all other parameters were significantly higher in the Surgicel than in the quercetin group. The quercetin + Surgicel group had lower adhesion scores than the quercetin group.

CONCLUSIONS

Quercetin, Surgicel and quercetin + Surgicel treatment may be useful for preventing pelvic adhesions.

Hyaluronic acid and oxidized regenerated cellulose prevent adhesion reformation after adhesiolysis in rat models

Postsurgical adhesion formation is the most common complication in abdominal and pelvic surgery. Adhesiolysis is the most commonly applied treatment for adhesion formation but is often followed by adhesion reformation. Therefore, an efficient strategy should be adopted to solve these problems. This study aimed to explore whether hyaluronic acid and oxidized regenerated cellulose (ORC) could prevent adhesion formation and reformation. Thirty female Sprague Dawley rats were randomly divided into three groups (n=10 each) and subjected to different treatments during the first and second surgery. The control group was treated with isotonic sodium chloride, the ORC group was treated with ORC (1.5×1 cm), and the medical sodium hyaluronate (MSH) group was treated with 1% MSH (0.5 mL). At 2 weeks after the first surgery, adhesion scores in the MSH group (1.90±0.99) and the ORC group (1.40±0.97) were significantly lower than those in the control group (3.00±0.82) (P=0.005). Similarly, 2 weeks after the second surgery, adhesion scores in the MSH group (2.00±0.82) and the ORC group (1.50±1.27) were significantly lower than those in the control group (3.50±0.53) (P=0.001). In addition, body weights in the MSH group and the ORC group did not change significantly, whereas the control group showed a consistent decrease in body weight during the experiment. Histological examination revealed that inflammatory infiltration was involved in both adhesion formation and reformation. In conclusion, hyaluronic acid and ORC were both efficient in reducing adhesion formation and reformation in the rat model.

Application of a hyaluronic acid gel after intrauterine surgery may improve spontaneous fertility: a randomized controlled trial in New Zealand White rabbits

Objective

Intrauterine adhesions (IUAs) are the most common complication after hysteroscopy in patients of reproductive age. Intra-abdominal anti-adhesion gel reduces the incidence of adhesions, but effects on fertility after uterine surgery are not known. The objective of our work was to evaluate the effect of intrauterine anti-adhesion gel on spontaneous fertility after repeated intrauterine surgery with induced experimental synechiae in the rabbit model.

Materials and Methods

Twenty New Zealand White rabbits underwent a double uterine curettage 10 days apart and were randomized into two groups. Each rabbit served as its own control: one uterine tube was the treatment group (A), the second uterine tube was the control group (B) to avoid bias through other causes of infertility. Group A received a post curettage intrauterine instillation of anti-adhesion gel whereas group B, the control group, underwent curettage without instillation of the gel. After a recovery period, the rabbits were mated. An abdominal ultrasound performed 21 days after mating allowed us to diagnose pregnancy and quantify the number of viable fetuses.

Results

There was a significant difference in total fetuses in favor of group A, with an average of 3.7 (range, 0–9) total fetuses per tube against 2.1 (0–7) in group B (p = .04). The number of viable fetuses shows a trend in favor of group A, with an average of 3.4 (0–7) viable fetuses per tube against 1.9 (0–6) viable fetuses per tube in group B (p = .05).

Conclusion

The use of immediate postoperative anti-adhesion gel improved fertility in an animal model after intrauterine surgery likely to cause uterine synechiae. This experimental model will permit comparison of different anti-adhesion solutions, including assessment of their tolerance and potential mucosal toxicity on embryonic development.

Evaluation of the effects of fulvestrant and micronized progesterone on the post-operative adhesion formation and ovarian reserve in rat model with immunohistochemical and biochemical analysis

OBJECTIVE

To evaluate the effects of fulvestrant and micronized progesterone on post-operative adhesion formation and ovarian reserve in a rat uterine horn adhesion.

METHODS

In this prospective randomized controlled trial, 32 female Wistar albino rats were randomly divided into four groups including control group (Group 1), the control adhesion group (Group 2), 1 mg/kg daily intramuscular fulvestrant received group (Group 3) and 1 mg/kg daily oral micronized progesterone received group (Group 4). The extent and severity of adhesions were scored and samples were taken from adhesion areas to investigate the grades of adhesions according to the immunohistochemical scoring system. Ovarian reserves were measured with anti-Müllerian hormone (AMH) and histological ovarian follicles count.

RESULTS

The extent, severity and total adhesion scores were reduced in all treatment groups compared to control adhesion group (Group 2). Similarly, immunohistochemical adhesion scores were lower in the treatment groups. AMH and follicle count were significantly found lower in adhesion groups compared with control group. However, treatment groups were found to have higher ovarian reserve compared to control adhesion group (Group 2).

CONCLUSIONS

Fulvestrant and micronized progesterone were found to reduce post-operative adhesion formations and have decreased detrimental effects of adhesion formation on ovarian reserve.