Intrauterine infusion of platelet‐rich plasma is a treatment method for patients with intrauterine adhesions after hysteroscopy

Abstract Objective To evaluate the efficacy of an intrauterine infusion of platelet‐rich plasma (PRP) in patients with intrauterine adhesions (IUAs). Methods A retrospective study was conducted from April 2018 to December 2019 to compare the efficacy of intrauterine infusion of PRP with balloon for patients with IUAs. All patients had moderate or severe IUAs, including 28 patients with intrauterine infusion of PRP (group A), 22 patients with intrauterine balloon (group B), and 20 patients with both intrauterine infusion of PRP and balloon in the first operative hysteroscopy. American Fertility Society (AFS) score and rates of chemical pregnancy were compared. Results The AFS score decreased with an average of 5.18 ± 3.93, 4.91 ± 4.39, and 5.15 ± 3.17 comparing the third hysteroscopy with the first operative hysteroscopy in group A, group B, and group C, respectively. No significant differences were found among these groups (P=0.734). The rates of chemical pregnancy were 40.0% in group A, 38.9% in group B, and 33.3% in group C without significant differences (P=0.944). Conclusion There were no significant differences between intrauterine infusion of PRP and balloon. PRP is a treatment method for IUAs.


| INTRODUCTION
Intrauterine adhesions (IUAs) are the major cause of uterine infertility and are characterized by endometrial damage because of endometritis or curettage. 1 Transcervical resection of the adhesions by hysteroscopy is the most effective and commonly used treatment method for IUAs, 1 followed by hormonal therapy, an intrauterine device or intrauterine balloon, cross-linked sodium hyaluronate, and oral antibiotics to prevent recurrent IUAs. However, high grades of IUAs mean increased risks of the spontaneous recurrence of adhesions. 2 For patients with severe IUAs, the incidence of spontaneous recurrent IUAs was reported to be 62.5%. 2 Platelet-rich plasma (PRP)-which has the potential to repair tissues including tendons, muscles, cartilage, and ligament-is increasingly used in orthopedics. 3 Clinical trials and retrospective cohort studies have shown that PRP is considered safe. 3 PRP decreases fibroblastic activity in animal experiments. 4 PRP treatment has also been applied in the treatment of hair loss, vulvar lichen sclerosus, lichen planopilaris, and other medical conditions. PRP also plays a positive role in the rejuvenation of tissue and wound healing. 5 Autologous PRP could promote endometrial growth and improve endometrial regeneration and endometrial capacity. The study by Chang et al. 6 observed successful endometrial growth after intrauterine infusions of PRP in all five patients who were pregnant.
Endometrial repair and the prevention of recurrent IUAs are the key objectives after the hysteroscopic separation of IUAs. The aim of the present study was to evaluate the efficacy of PRP in the treatment of IUAs.

| Participant criteria
The present study enrolled infertile women with moderate or severe IUAs. Patients with uterine malformations, endometrial polyps, submucous myomas, intrauterine hyperplasia, malignancies of the female reproductive system, premature ovarian failure, and/or endometrial tuberculosis were excluded. The study was approved by the Ethics Committee of the Sixth Affiliated Hospital of Sun Yat-sen University.
According to the AFS system, 7 AFS scores of 9-12 were regarded as severe IUAs, while AFS scores of 5-8 were regarded as moderate

| Preparation of PRP and PRP activator
The PRP was prepared from a modified method from Yamaguchi et al. 8 On the day of the first hysteroscopy, 15 mL of peripheral venous blood was drawn with a syringe with 5 mL of anticoagulant solution (ACD anticoagulant; Shanghai GENMED Medicine Technology Co., Ltd., Shanghai, China) and then centrifuged at 200 g for 10 minutes.
Three layers could be found, and the upper and mid layers (plasma layer and buffy coat layer, respectively) were collected into another tube. Then they were centrifuged at 500 g for 10 minutes. The pellet of platelets was mixed with 1 mL of supernatant and 0.5-1 mL of PRP could be obtained. 6 The concentration of platelets is 3662.0 ± 1351.1 (2SD) × 10 9 /L.
The PRP activator was prepared as follows: 2 mL of 5% calcium chloride injection (Shanghai Xinyi Jinzhu Pharmaceutical Co., Ltd., Shanghai, China) was mixed with 10 mL of 0.9% sodium chloride injection (Otsuka Pharmaceutical Co., Ltd., Tianjin, China) and then centrifuged immediately at 200 g for 1 minute. Then, 2 mL of the mixed solution was discarded and the remaining 10 mL of the mixture was preserved (solution A). Two bottles of Thrombin 500 U (Hunan Yige Pharmaceutical Co., Ltd., Xiangtan, China) were then dissolved with 10 mL of 0.9% sodium chloride injection (Otsuka Pharmaceutical Co., Ltd., Tianjin, China) (solution B). The PRP activator was the mixture of solution A and solution B, with a ratio of 1:1.
The mixture of PRP and PRP activator (with a ratio of 1:1) would be infused into the uterine cavity with a catheter for intrauterine insemination (Shenzhen Huanhao Technologies Co., Ltd., Shenzhen, China).

| RESULTS
In the present study, 38 patients in group A, 32 patients in group B, and 24 patients in group C were initially included. Some patients did

| DISCUSSION
The presence of IUAs impacts subsequent pregnancies 9 and hysteroscopic procedures are the most common treatment for patients with IUAs. Despite a successful initial surgery, the reformation of IUAs occurred in approximately one-third of patients and the incidence of recurrent IUAs was reported to be approximately two-thirds of women with severe IUAs. 2 Endometrium growth is one of the most important factors in pregnancy, so the prevention of recurrent IUAs and promotion of endometrial repair are the key objectives that should be considered after hysteroscopic surgery. Barrier gels, hormonal treatment, and intrauterine balloons are usually applied in patients with IUAs after an operative hysteroscopy. 10 However, no significant or clear improvements in clinical symptoms and rates of subsequent pregnancies have been found. 11,12 In 2006, Amer and Abd-El-Maeboud 13 found that an amniotic membrane was an effective method for reducing the recurrence of IUAs and promoting endometrial regeneration. However, amniotic membranes did not affect the incidence of recurrence of IUAs or the rate of pregnancy. 14 For patients with recurrent IUAs, allogeneic cell therapy with mesenchymal stem cells (MSCs) from the umbilical cord was a safe and effective therapeutic method. 15 PRP is defined as the plasma fraction of autologous blood with platelet numbers that are enhanced four-to six-fold compared with that of whole blood. 16 There was no significant difference in the change of AFS scores among these three groups in the present study. Furthermore, there was no significant difference in rates of chemical pregnancy after embryo transfers among these groups.
PRP can play an important role in wound healing, preventing recurrent IUAs, and promoting endometrial repair. First, the fibrin and high concentrations of platelets in the PRP contribute to hemostasis and prevent acute blood loss after hysteroscopic surgery. 17,18 The fibrin and platelets can promote wound healing after hysteroscopy.
Second, white blood cells in the PRP may play an important role against infection after hysteroscopy. Third, unlike the intrauterine balloon, the fluidity of PRP helps the patient to avoid distending pain and foreign body sensations. In addition, PRP is not expensive.
Fourth, PRP is autologous; therefore, it can avoid transplant rejection. The risk of transmission of disease and immunogenic reactions can also be avoided. 19 Finally, and most importantly, growth factors, including TGF-β, PDGF, EGF-F, VEGF, and FGF, can promote the healing process. 18,19 Growth factors can also regulate cell migration, attachment, and proliferation and promote the accumulation of extracellular matrix. 20 Moreover, growth factors can stimulate neovascularization of the endometrium and promote endometrial repair. Angiogenesis promoted by growth factors plays a critical role in tissue growth and repair. 21 The estrogen in hormone treatments contributes to thrombosis and fibrosis, which may result in recurrent IUAs or unsatisfactory endometrial repair. 22 This may be resolved by the growth factors in PRP.
Early second-look hysteroscopic examinations within 2 months may improve clinical outcomes 23,24 ; therefore, an advanced secondlook hysteroscopy was carried out after the first operative hysteroscopy, and a third-look hysteroscopy was carried out in the follicular phase of the next menstrual cycle as part of routine treatment. No significant recurrent IUAs were found in the second-look hysteroscopy so none of the patients included in the final analysis received blunt dissection in the second-look hysteroscopy. Satisfactory results were achieved in the cases with a third-look hysteroscopy, including results indicating endometrial repair and a normal-or almost normaluterine cavity. Significantly decreased AFS scores were found in all groups with a third-look hysteroscopy. No surgical complications were observed in the three groups, and the intrauterine infusion of PRP is considered safe, as reported in other studies. 25 In conclusion, there were no significant differences between the intrauterine infusion of PRP and the intrauterine balloon. PRP is a form of treatment for IUAs after operative hysteroscopy and may be T A B L E 1 Basic characteristics of the participants in groups A, B, and C in the final analysis.

Age (years)
Artificial abortion or curettage a substitute for the intrauterine balloon. However, randomized controlled trials with large sample sizes are warranted to further confirm the conclusions of the present study and to compare the efficacy of intrauterine infusions of PRP with intrauterine balloons applied immediately after transcervical resection of the adhesions by hysteroscopy in patients with IUAs.

AUTHOR CONTRIBUTIONS
JP and ML contributed to data collection, data analysis, and writing the manuscript. Both JP and ML contributed equally to this study. XL contributed to the study design and revising the manuscript. JP, ML, HZ, and ZZ performed the surgical procedures. JH contributed to data collection. All authors approved the final version of the manuscript for publication.