Strategies to manage refractory endometrium: state of the art in 2016

Evolution of biotechnological advances and regenerative therapies for endometrial disorders: a systematic review

BACKGROUND

The establishment and maintenance of pregnancy depend on endometrial competence. Asherman syndrome (AS) and intrauterine adhesions (IUA), or endometrial atrophy (EA) and thin endometrium (TE), can either originate autonomously or arise as a result from conditions (i.e. endometritis or congenital hypoplasia), or medical interventions (e.g. surgeries, hormonal therapies, uterine curettage or radiotherapy). Affected patients may present an altered or inadequate endometrial lining that hinders embryo implantation and increases the risk of poor pregnancy outcomes and miscarriage. In humans, AS/IUA and EA/TE are mainly treated with surgeries or pharmacotherapy, however the reported efficacy of these therapeutic approaches remains unclear. Thus, novel regenerative techniques utilizing stem cells, growth factors, or tissue engineering have emerged to improve reproductive outcomes.

OBJECTIVE AND RATIONALE

This review comprehensively summarizes the methodologies and outcomes of emerging biotechnologies (cellular, acellular, and bioengineering approaches) to treat human endometrial pathologies. Regenerative therapies derived from human tissues or blood which were studied in preclinical models (in vitro and in vivo) and clinical trials are discussed.

SEARCH METHODS

A systematic search of full-text articles available in PubMed and Embase was conducted to identify original peer-reviewed studies published in English between January 2000 and September 2023. The search terms included: human, uterus, endometrium, Asherman syndrome, intrauterine adhesions, endometrial atrophy, thin endometrium, endometritis, congenital hypoplasia, curettage, radiotherapy, regenerative therapy, bioengineering, stem cells, vesicles, platelet-rich plasma, biomaterials, microfluidic, bioprinting, organoids, hydrogel, scaffold, sheet, miRNA, sildenafil, nitroglycerine, aspirin, growth hormone, progesterone, and estrogen. Preclinical and clinical studies on cellular, acellular, and bioengineering strategies to repair or regenerate the human endometrium were included. Additional studies were identified through manual searches.

OUTCOMES

From a total of 4366 records identified, 164 studies (3.8%) were included for systematic review. Due to heterogeneity in the study design and measured outcome parameters in both preclinical and clinical studies, the findings were evaluated qualitatively and quantitatively without meta-analysis. Groups using stem cell-based treatments for endometrial pathologies commonly employed mesenchymal stem cells (MSCs) derived from the human bone marrow or umbilical cord. Alternatively, acellular therapies based on platelet-rich plasma (PRP) or extracellular vesicles are gaining popularity. These are accompanied by the emergence of bioengineering strategies based on extracellular matrix (ECM)-derived hydrogels or synthetic biosimilars that sustain local delivery of cells and growth factors, reporting promising results. Combined therapies that target multiple aspects of tissue repair and regeneration remain in preclinical testing but have shown translational value. This review highlights the myriad of therapeutic material sources, administration methods, and carriers that have been tested.

WIDER IMPLICATIONS

Therapies that promote endometrial proliferation, vascular development, and tissue repair may help restore endometrial function and, ultimately, fertility. Based on the existing evidence, cost, accessibility, and availability of the therapies, we propose the development of triple-hit regenerative strategies, potentially combining high-yield MSCs (e.g. from bone marrow or umbilical cord) with acellular treatments (PRP), possibly integrated in ECM hydrogels. Advances in biotechnologies together with insights from preclinical models will pave the way for developing personalized treatment regimens for patients with infertility-causing endometrial disorders such as AS/IUA, EA/TE, and endometritis.

REGISTRATION NUMBER

https://osf.io/th8yf/.

Sodium alginate hydrogel integrated with type III collagen and mesenchymal stem cell to promote endometrium regeneration and fertility restoration

A thinner endometrium has been linked to implantation failure, and various therapeutic strategies have been attempted to improve endometrial regeneration, including the use of mesenchymal stem cells (MSCs). However, low survival and retention rates of transplanted stem cells are main obstacles to efficient stem cell therapy in thin endometrium. Collagen type III is a key component of the extracellular matrix, plays a crucial role in promoting cell proliferation and differentiation, and has been identified as the major collagen expressed at the implantation site. Herein, composite alginate hydrogel containing recombinant type III collagen (rCo III) and umbilical cord mesenchymal stem cells are developed. rCo III serves as favorable bioactive molecule, displaying that rCo III administration promotes MSCs proliferation, stemness maintenance and migration. Moreover, rCo III administration enhances cell viability and migration of mouse endometrial stromal cells (ESCs). In a mouse model of thin endometrium, the Alg-rCo III hydrogel loaded with MSCs (MSC/Alg-rCo III) significantly induces endometrial regeneration and fertility enhancement in vivo. Further studies demonstrate that the MSC/Alg-rCo III hydrogel promoted endometrial function recovery partly by regulating mesenchymal-epithelial transition of ESCs. Taken together, the combination of Alg-rCo III hydrogel and MSCs has shown promising results in promoting endometrium regeneration and fertility restoration, and may provide new therapeutic options for endometrial disease.

Use of platelet lysate for in-vitro embryo production and treatment of repeat breeding in cows

Platelet-rich plasma (PRP) is a biological hemocomponent derived from blood after the complete removal of red blood cells and the partial or complete removal of white blood cells to concentrate platelets in an appropriate volume of plasma. Platelets have important growth factors, cytokines, and active metabolites that improve the endometrial environment and positively affect implantation. This study evaluated the effect of the addition of activated PRP (platelets lysate; PL) on in vitro bovine oocyte maturation and embryonic development and the effect of intrauterine (IU) infusion of autologous PL in repeat breeder (RB) cows. Experiment 1 examined the effects of allogeneic PL, fetal calf serum (FCS), mixed PL + FCS, or platelet-poor plasma (PPP) supplementations to in vitro maturation and development media on in vitro oocyte maturation and embryo development in good- and poor-quality oocytes of Japanese Black cows. Experiment 2 examined the IU infusion of autologous PL, 24 h post-insemination, in 21 RB Holstein-Friesian dairy cows. The cleavage rate of good-quality oocytes was higher in the PL group (85.93 ± 2.50%) than in the PPP group (67.16 ± 3.41%) (P < 0.05), while the cleavage rate of the poor-quality oocytes was higher in the PL alone (76.13 ± 4.04%) and mixed PL + FCS treated (73.59 ± 4.22%) groups than in the PPP group (54.64 ± 2.93%) (P < 0.05). The blastocyst rate of the good-quality oocytes was higher in the PL group (40.97 ± 3.03%) than in the FCS (27.97 ± 3.31%) and PPP (25.33 ± 2.15%) groups (P < 0.05). The blastocyst rate of poor-quality oocytes and the hatching rates of both good and poor-quality oocytes showed no significant differences among all groups. The conception rate in the autologous PL-treated group was 41.67% (5/12), while it was 11.11% (1/9) in the control group. The platelets' count in the pregnant PL-treated cows (n = 5; mean ± SEM, 1.07 ± 0.10 × 109/mL) was higher than in the non-pregnant ones (n = 7; 0.67 ± 0.10 × 109/mL) (P < 0.05). In conclusion, allogeneic PL was effective in stimulating the in vitro oocyte maturation and embryonic development in both good and poor-quality bovine oocytes, and post-insemination IU infusion of autologous PL derived from high platelets' count-PRP would be recommended for the treatment of RB cows.

Factors Affecting the Potential Efficacy of Intrauterine Platelet-Rich Plasma Infusion on Thin Endometrium in Women with Recurrent Implantation Failure

Optimizing endometrial thickness (EMT) is crucial for successful embryo implantation, but enhancing thin endometrium remains a significant challenge. Platelet-rich plasma (PRP)-derived therapies have emerged as a promising approach in reproductive medicine due to their capacity to facilitate tissue repair and regeneration. This study aims to identify the risk factors associated with the failure of intrauterine PRP infusion for thin endometrium in women with recurrent implantation failure (RIF). We retrospectively reviewed data from 77 women with RIF, all exhibiting an EMT of <7 mm. These women underwent programmed hormone therapy for frozen embryo transfer (FET) and received two autologous intrauterine PRP infusions. Following intrauterine PRP-lysate (PL) infusions, the mean increase in EMT was 1.9 ± 1.2 mm, with EMT reaching 7 mm in 86% of the cases (66/77; average EMT, 8.3 mm). We identified an exceedingly thin EMT as a risk factor impacting the therapeutic efficacy in increasing EMT (p = 0.04, OR: 3.16; 95% CI: 1.03-9.67). Additionally, the number of previous uterine surgeries emerged as a prognostic factor for pregnancy failure following PL infusion (p = 0.02, OR: 2.02; 95% CI: 1.12-3.64). Our findings suggest that an extremely thin EMT and a history of numerous uterine surgeries can impede successful pregnancy, even when an optimal EMT is achieved following PRP infusion.

Intrauterine instillation of autologous platelet-rich plasma in infertile females with thin endometrium undergoing intrauterine insemination: an open-label randomized controlled trial

BACKGROUND

Thin endometrium in infertile female patients has always been a clinical challenge for the treating reproductive physicians.

OBJECTIVE

This study aimed to evaluate the effect of intrauterine instillation of autologous platelet-rich plasma on endometrial thickness and vascularity in infertile female patients with thin endometrium undergoing ovarian stimulation with intrauterine insemination.

STUDY DESIGN

This prospective randomized control study included 120 women undergoing ovarian stimulation with intrauterine insemination, aged between 21 and 37 years, with persistent thin endometrium (<7 mm) on ≥1 cycle in previous ovarian stimulation cycles, even after conventional treatment with estradiol valerate. The women were randomly assigned to study group A and control group B. Baseline endometrial thickness and endometrial vascularity were noted. Intrauterine instillation of autologous platelet-rich plasma was done on the day of trigger in group A, whereas estradiol valerate was given in group B. Another evaluation of endometrial parameters was done on the day of intrauterine insemination. The cycle was repeated for 3 cycles or until the pregnancy was achieved, whichever occurred earlier. Parameters were noted for both groups. Primary outcomes were the change in endometrial thickness and endometrial vascularity. Secondary outcomes were positive pregnancy rate and clinical pregnancy rate.

RESULTS

In group A, mean pre-platelet-rich plasma endometrial thickness was 4.66±0.79 mm, which significantly increased to 7.47±0.85 mm after platelet-rich plasma instillation (P<.05) after 3 cycles. This increase was significantly greater than that observed in group B. There was significant increase in endometrial vascularity in group A compared with group B (P<.05). The positive pregnancy rate and clinical pregnancy rate in group A were 23.73% and 18.64%, respectively, and significantly higher than those in group B.

CONCLUSION

Autologous platelet-rich plasma is a promising, easily procurable, and novel option for management of infertile females with thin endometrium not responding to conventional treatment. Using it in intrauterine insemination cycles can reduce costs and psychological burden of this subgroup of women by reducing the need for resorting to advanced options such as in vitro fertilization and surrogacy.

Prospects for the use of autologous platelet-rich plasma in reproductive medicine. Analysis of literary data

A brief review of the literature summarizing PubMed (MEDLINE) data is presented, which describes the use of autologous platelet-rich plasma in reproductive medicine. The main biologically active factors included in the composition of platelets are indicated: vascular endothelial growth factor, transforming growth factor, platelet growth factor and epidermal growth factor. The main biological changes occurring under the action of platelet activation are noted: control of migration, differentiation and proliferation of cells, accumulation of extracellular matrix, etc. The main methods and methods of using autologous platelet-rich plasma in the treatment of patients with thin endometrium are described, the main advantages of this method are indicated. The prospects of using this therapy in reproductive medicine for the purpose of effective treatment of patients with infertility are shown.

Endometrial preservation during resection of type II and type III submucosal fibroids

Background and objectives: Hysteroscopic myomectomy is considered the gold-standard treatment of submucosal fibroids. However, it is associated with disruption of the endometrium which may lead to complications such as intrauterine adhesions and loss of functional endometrium. In this video article we describe a technique to resect Type III and Type II fibroids whilst minimising the loss of overlying endometrium. Materials and methods: We present two patients with type II/III submucosal fibroids with minimal or no intracavitary component. The resection technique we demonstrate comprises either making an endometrial incision or making a small opening in the overlying endometrium to expose the fibroid pseudocapsule. Subsequent steps of resection are then performed through this small opening. Thus, complete resection is achieved without further resection of the endometrium. Main outcome measures: Evidence of endometrial healing and absence of intrauterine synechiae on follow up outpatient hysteroscopy or ultrasound scan. Results: Full resection was achieved in both patients with no or minimal loss of overlying endometrium. A follow up outpatient hysteroscopy was performed 8 weeks later in the first patient, demonstrating completely healed uterine cavity. She had a successful conception and delivery following IVF treatment for male factor infertility. The second patient is currently in the process of IVF treatment. Conclusions: Our technique enables endometrial preservation and potentially better reproductive outcomes following resection of type II and type III submucosal fibroids. Larger scale studies are required to elucidate long term outcomes on bigger patient population.

Effectiveness of phosphodiesterase type 5 inhibitors on the treatment of thin endometrium and pregnancy outcomes: An systematic review

Phosphodiesterase type 5 (PDE5) inhibitors are thought to play a role in increasing endometrial thickness and increasing the success rate of pregnancy outcomes. This study was done to investigate the effects of PDE5 inhibitors on infertile women with thin endometrium and pregnancy outcomes. In this systematic review, all randomized controlled trials (RCTs) and observational studies were retrieved from databases including Institute for Scientific Information (ISI), PubMed, and Scopus by interesting keywords. A checklist was designed to collect necessary data and pregnancy outcomes, and the required items were recorded. PDE5 inhibitors through various mechanisms such as induction of vasodilatory effect through the effect on NO/cGMP signaling on vascular smooth muscle, through regulating cells proliferation and induction angiogenesis by increasing the expression of tumor suppressor factor (p53), and vascular endothelial growth factor A (VEGF-A) and downregulating inflammation by downregulating proinflammatory cytokines, affect endometrial thickness that eventually increases and pregnancy outcomes. Although PDE5s inhibitors increase endometrial thickness by different mechanisms, especially in women with thin endometrial, this does not necessarily mean that they induce a positive effect in all situations. However, their positive effects on pregnancy outcome may be affected by the time of administration, type of infertility treatment, underlying diseases such as pelvic disorders and inflammation. So in this regard, there are still ambiguous aspects that required further RCTs study in this area.

A Novel Xeno-Free Method to Isolate Human Endometrial Mesenchymal Stromal Cells (E-MSCs) in Good Manufacturing Practice (GMP) Conditions

The cyclic regeneration of human endometrium is guaranteed by the proliferative capacity of endometrial mesenchymal stromal cells (E-MSCs). Due to this, the autologous infusion of E-MSCs has been proposed to support endometrial growth in a wide range of gynecological diseases. We aimed to compare two different endometrial sampling methods, surgical curettage and vacuum aspiration biopsy random assay (VABRA), and to validate a novel xeno-free method to culture human E-MSCs. Six E-MSCs cell samples were isolated after mechanical tissue homogenization and cultured using human platelet lysate. E-MSCs were characterized for the colony formation capacity, proliferative potential, and multilineage differentiation. The expression of mesenchymal and stemness markers were tested by FACS analysis and real-time PCR, respectively. Chromosomal alterations were evaluated by karyotype analysis, whereas tumorigenic capacity and invasiveness were tested by soft agar assay. Both endometrial sampling techniques allowed efficient isolation and expansion of E-MSCs using a xeno-free method, preserving their mesenchymal and stemness phenotype, proliferative potential, and limited multi-lineage differentiation ability during the culture. No chromosomal alterations and invasive/tumorigenic capacity were observed. Herein, we report the first evidence of efficient E-MSCs isolation and culture in Good Manufacturing Practice compliance conditions, suggesting VABRA endometrial sampling as alternative to surgical curettage.

Recent trends in therapeutic strategies for repairing endometrial tissue in intrauterine adhesion

Intrauterine adhesion (IUA) is a common gynaecological disease that develops from infection or trauma. IUA disease may seriously affect the physical and mental health of women of childbearing age, which may lead to symptoms such as hypomenorrhea or infertility. Presently, hysteroscopic transcervical resection of adhesion (TCRA) is the principal therapy for IUAs, although its function in preventing the recurrence of adhesion and preserving fertility is limited. Pharmaceuticals such as hormones and vasoactive agents and the placement of nondegradable stents are the most common postoperative adjuvant therapy methods. However, the repair of injured endometrium is relatively restricted due to the different anatomical structures of the endometrium. Recently, the treatment outcome of IUAs has improved with the advancement of hysteroscopic techniques. In particular, the application of bioactive scaffolds combined with tissue engineering technology has proven to have high therapeutic potential or endometrial repair in IUA treatment. Herein, this review has summarized past therapeutic strategies, including postoperative adjuvant therapy, cell or therapeutic molecular delivery therapy methods and bioactive scaffold-based tissue engineering methods. Therefore, this review presented the recent therapeutic strategies for repairing endometrium treatment and pointed out the issues of clinical concern to provide alternative methods for the management of IUAs.

Strategies for managing asherman's syndrome and endometrial atrophy: Since the classical experimental models to the new bioengineering approach

Endometrial function is essential for embryo implantation and pregnancy, but managing endometrial thickness that is too thin to support pregnancy or an endometrium of compromised functionality due to intrauterine adhesions is an ongoing challenge in reproductive medicine. Here, we review current and emerging therapeutic and experimental options for endometrial regeneration with a focus on animal models used to study solutions for Asherman's syndrome and endometrial atrophy, which both involve a damaged endometrium. A review of existing literature was performed that confirmed the lack of consensus on endometrial therapeutic options, though promising new alternatives have emerged in recent years (platelet-rich plasma, exosomes derived from stem cells, bioengineering-based techniques, endometrial organoids, among others). In the future, basic research using established experimental models of endometrial pathologies (combined with new high-tech solutions) and human clinical trials with large population sizes are needed to evaluate these emerging and new endometrial therapies.

Transplantation of Human Adipose Stem Cells Using Acellular Human Amniotic Membrane Improves Angiogenesis in Injured Endometrial Tissue in a Rat Intrauterine Adhesion Model

Endometrial injury resulting in intrauterine adhesion is associated with extensive damage to the regenerative basal layer of the endometrium and represents a major therapeutic challenge. Human adipose stem cells (hASCs) hold promise for future clinical use in the individualized therapy of injured endometrial tissue. Here, we observed that the use of the acellular human amniotic membrane (AHAM) significantly increased the expression of angiogenic factors, including angiogenin (ANG) and vascular endothelial growth factor (VEGF), in hASCs in vitro. The three-dimensional engineered hASC-AHAM grafts significantly increased the endometrial receptivity, as increased endometrial thickness, greater numbers of endometrial glands, and higher protein levels of leukemia inhibitory factor were observed in injured endometrial tissue that was treated with these grafts compared to those detected in injured endometrial tissue that was treated with AHAM alone. In addition, the hASC-AHAM grafts significantly increased the vascular density in the injured endometrial tissue in rats, when transplanted into an injured uterine cavity. Using the EGFP⁺-hASC-AHAM grafts for transplantation, we confirmed that the hASCs maintained higher protein levels of ANG and VEGF in the injured uterine cavity in vivo. The results of this study suggest that the ability of the engineered hASC-AHAM grafts to repair injured endometrial tissue may be associated with their ability to promote angiogenesis through the upregulated expression of angiogenic factors in hASCs. These findings may support individualized stem cell–based therapy for endometrial disease using bioartificial grafts.

Use of Intra-uterine Injection of Platelet-rich Plasma (PRP) for Endometrial Receptivity and Thickness: a Literature Review of the Mechanisms of Action

Endometrial receptivity and thickness play an important role in achieving a pregnancy. Intrauterine autologous platelet-rich plasma (PRP) infusion has been used in infertile women with recurrent implantation failure (RIF) and thin endometrial lining thickness (EMT). Literature search was performed in PubMed for studies including in vitro, animal, and human studies as well as in abstracts presented at national conferences. Animal studies demonstrated a decrease in the expression of inflammatory markers and fibrosis, and increased endometrial proliferation rate, increased expression of proliferative genes, and increased pregnancy rates. The in vitro studies showed that PRP was associated with increased stromal and mesenchymal cell proliferation, increased expression of regenerative enzymes, and enhancement in cell migration. In infertile women undergoing assisted reproductive technology, one randomized clinical trial showed that PRP intrauterine infusion improved EMT, implantation rate, and clinical pregnancy rate (CPR) in patients with thin EMT, while 3 other trials involving subjects with RIF showed conflicting results related to CPR. Case series and cohort studies showed conflicting results pertaining to CPR. Data to date suggest that PRP may be beneficial in improving endometrial thickness and endometrial receptivity. However, further large prospective and high-quality trials are needed to assert its effect and to identify the population of patients that would benefit the most.

Electroacupuncture Improves Pregnancy Outcomes in Rats with Thin Endometrium by Promoting the Expression of Pinopode-Related Molecules

A thin endometrium affects the success of assisted reproduction due to low endometrial receptivity. Acupuncture improves endometrial receptivity and promotes the formation of pinopodes, the ultrastructure marker implantation window. However, the specific underlying mechanisms remain unclear. In this study, the efficacy of acupuncture treatment and its underlying mechanism were investigated by analyzing pregnancy rate, pinopode formation, and related molecular markers in thin endometrium model rats. Absolute ethanol (95%) was injected into the uteruses of female Sprague-Dawley rats to construct a thin endometrium model. In this model, acupuncture stimulation at EX-CA1, SP6, and CV4 ameliorated the pregnancy rate. Significantly increased embryo implantation, endometrial thickness, numbers of glands, and blood vessels were observed in the electroacupuncture (EA) group compared to the model group. The number of pinopodes in the EA group was abundant, with a shape similar to that of the control group. Additionally, significantly higher expression levels of pinopode-related markers, including integrin αvβ3, homeobox A10 (HOXA10), heparin-binding EGF-like growth factor (HBEGF), estrogen receptor alpha (ERα), and progesterone receptor (PR), were observed in the EA group than those in the model group. In conclusion, EA had a positive effect on the endometrial receptivity of thin endometrium model rats by improving pinopode formation through multiple molecular targets.

Platelet-Rich plasma as an effective alternative approach for improving endometrial receptivity - a clinical retrospective study

Objective:

The aim of the present case series was to describe our experience with the use of PRP on patients with refractory thin endometria.

Methods:

This retrospective analysis included 24 IVF cycles in which patients presenting different infertility factors received intrauterine PRP infusion prior to embryo transfer. Outcomes of interest were: clinical and ongoing pregnancies, miscarriages, and births.

Results:

54% of the cycles in which PRP was employed resulted in ongoing gestation or birth; 12.5% of the cycles ended in miscarriages.

Conclusion:

Our data suggest that PRP improves intrauterine receptivity to embryo implantation, regardless of whether the endometrium reached the appropriate growth for embryo transfer.

Platelet-rich plasma another add-on treatment getting out of hand? How can clinicians preserve the best interest of their patients?

Add-on treatments in IVF are utilized to a great extent but without sufficient evidence showing their effectiveness. Since the offered treatments are usually costly and may be associated with yet unknown risks, this practice is not in the best interest of couples that may go to great lengths to conceive and have an offspring carrying their own genetic make-up. A recent addition to this armamentarium is the administration of platelet-rich plasma (PRP) in women with diminished ovarian reserve, implantation failures, and a thin endometrium. The only evidence for PRP comes from small scale and mostly before and after studies with clinically irrelevant end points. PRP has not been subjected to a rigorous clinical trial. It is a typical example of an add-on gaining widespread popularity based on biological plausibility and mind-bending theoretical presumptions. We should be extremely cautious prior to implementing PRP on a widescale and await the results of well-designed studies.

Platelet-rich plasma (PRP) therapy: An approach in reproductive medicine based on successful animal models

Platelet-rich plasma (PRP) has been fully studied for different clinical applications in veterinary medicine for many years with promising results. As a result, therapeutic studies to elucidate pathways for PRP use in human reproduction have been performed. PRP applications in human reproductive medicine are recent, but the role of platelet growth factors in improving the endometrial environment is well known. Indications for PRP therapy show its positive effects in promoting endometrial and follicular growth and gestation in assisted reproduction cycles, as has been proven in animals. We summarized the putative role of PRP on endometrial receptivity with a brief history of promising results in research and clinical therapies.

Does low-dose aspirin initiated before 11 weeks' gestation reduce the rate of preeclampsia?

OBJECTIVE DATA

Preconception or early administration of low-dose aspirin might improve endometrial growth, placental vascularization, and organogenesis. Most studies have evaluated the potential benefit of preconception or early administration of low-dose aspirin in women with a history of recurrent pregnancy loss, women who have undergone in vitro fertilization, or women with thrombophilia or antiphospholipid syndrome. These women are at an increased risk of placenta-associated complications of pregnancy, including preeclampsia, preterm delivery, and fetal growth restriction.

STUDY OUTCOMES

We performed a systematic review and meta-analysis to evaluate the effect of low-dose aspirin initiated at <11 weeks' gestation on the risk of preeclampsia, gestational hypertension, or any hypertensive disorder of pregnancy. Secondary outcomes included preterm delivery at <37 weeks' gestation and fetal growth restriction.

STUDY APPRAISAL AND SYNTHESIS METHODS

We searched in MEDLINE via PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform from 1985 to November 2018. Entry criteria were randomized controlled trials evaluating the effect of aspirin administered at <11 weeks' gestation in preventing preeclampsia and/or hypertensive disorders in pregnancy or improving pregnancy outcomes in women with recurrent miscarriage as compared with placebo or no treatment and outcome data available or provided by authors for >85% of the study population. Relative risks with 95% confidence intervals were calculated for each study and pooled for global analysis as the effect measure. We assessed statistical heterogeneity in each meta-analysis using the χ² statistics, I², and Tau². Heterogeneity was considered substantial if an I² was greater than 50% and either the Tau² was greater than zero or there was a low P value (<0.10) in the χ² test for heterogeneity. Random-effects meta-analysis, weighted by the size of the studies, was performed to produce an overall summary on aspirin effect for each outcome. Sensitivity analysis by sequential omission of each individual study and by fixed-effects model was performed. Publication bias was not assessed because of the small number of included studies. Statistical analysis was performed using Stata release 14.0 (StataCorp).

RESULTS

The entry criteria were fulfilled by 8 randomized controlled trials on a combined total of 1426 participants. Low-dose aspirin initiated at <11 weeks' gestation was associated with a nonsignificant reduction in the risk of preeclampsia (relative risk, 0.52; 95% confidence interval, 0.23-1.17, P = .115), gestational hypertension (relative risk, 0.49; 95% confidence interval, 0.20-1.21; P = .121), and any hypertensive disorder of pregnancy (relative risk, 0.59; 95% confidence interval, 0.33-1.04, P = .067). Early administration of low-dose aspirin reduced the risk of preterm delivery (relative risk, 0.52; 95% confidence interval, 0.27-0.97, P = .040) but had no impact on the risk of fetal growth restriction (relative risk, 1.10; 95% confidence interval, 0.58-2.07, P = .775). Except for preterm delivery and any hypertensive disorder of pregnancy, sensitivity analysis demonstrated similar observations, therefore confirming the robustness of the analysis.

CONCLUSION

The administration of low-dose aspirin at <11 weeks' gestation in women at high risk does not decrease the risk of preeclampsia, gestational hypertension, any hypertensive disorder of pregnancy, and fetal growth restriction. However, it might reduce the risk of preterm delivery. Larger randomized controlled trials will be required to substantiate the findings.

Platelet-inspired therapeutics: current status, limitations, clinical implications, and future potential

Recent research has been successful in demonstrating the importance of the addition of platelets to the field of cell-mediated therapeutics, by making use of different platelet forms to design modalities able to positively impact a wide range of diseases. A key obstacle hindering the success of conventional therapeutic interventions is their inability to produce targeted treatment, resulting in a number of systemic side effects and a longer duration for the onset of action to occur. An additional challenge facing current popular therapeutic interventions is biocompatibility of the system, resulting in the decline of patient compliance to treatment. In an attempt to address these challenges, the past few decades have been witness to the discovery and innovation of precision therapy, in order to achieve targeted treatment for an array of conditions, thereby superseding alternative mechanisms of treatment. Platelet-mediated therapeutics, as well as employing platelets as drug delivery vehicles, are key components in advancing precision therapy within research and in clinical settings. This novel approach is designed with the objective that the platelets retain their original structure and functions within the body, thereby mitigating biocompatibility challenges. In this article, we review the current significant impact that the addition of platelet-inspired systems has made on the field of therapeutics; explore certain limitations of each system, together with ideas on how to overcome them; and discuss the clinical implications and future potential of platelet-inspired therapeutics. Graphical abstract.

The effect of platelet-rich plasma on the achievement of pregnancy during frozen embryo transfer in women with a history of failed implantation

Objective

The aim of this study was to evaluate the effect of platelet-rich plasma (PRP) on the rate of implantation and pregnancy in women with repeated failed implantation during frozen embryo transfer.

Methods

This study was conducted on 50 infertile women candidates (who were referred to the Infertility Treatment Center of Besat Hospital in Sanandaj) with a history of failed implantation for the purpose of frozen embryo transfer. The participants were randomly divided into two groups (n = 25). In the first group (control), the intrauterine infusion of 0.5 ml of Ringer serum was done 48 h before embryo transfer. In the second group (treatment), the intrauterine infusion of 0.5 ml of PRP was performed 48 h before embryo transfer.

Results

In this study, there was no significant difference between the two groups in the rate of chemical and clinical pregnancy. The rate of chemical pregnancy was 28% in the treatment group and 36% in the control group, while the rate of clinical pregnancy was 28% in the treatment group and 24% in the control group.

Conclusion

The intrauterine infusion of PRP before frozen embryo transfer in infertile women with a history of failed implantation will not make any significant effect on the result of pregnancy.

The incidence rate of unresponsive thin endometrium in frozen embryo transfer cycles: A case-series of therapy with granulocyte colony stimulating factor

Background

Treatment-resistant thin endometrium (TTE) during in-vitro fertilization is a relatively uncommon and challenging problem.

Objective

The primary aim of the study was to assess the TTE rate during frozen embryo transfer (FET) cycles and the secondary aim was to evaluate the effect of intrauterine instillation of granulocyte colony stimulating factor (G-CSF) in these cases.

Materials and Methods

In this cross-sectional study, all of the women who underwent FET cycles with hormonal endometrial preparation in Royan Institute from June 2015 to March 2018 were evaluated and all of the cases with TTE diagnosis (endometrial thickness < 7 mm after using high doses of estradiol) were included. In the eligible cases, 300 μgr of G-CSF was infused intrauterine. If the endometrium had not reached at least a 7-mm, a second infusion was prescribed within 48 hr later.

Results

During the study, 8,363 of FET cycles were evaluated and a total of 30 infertile patients (0.35%) with TTE diagnosis were detected. Finally, 20 eligible patients were included. The changes of endometrial thickness after G-CSF therapy were significant (p < 0.001); however, the endometrial thickness did not reach 7 mm in nine patients (45%) and the embryo transfer was canceled.

Conclusion

It was found that the rate of TTE during the FET cycle is very low and intrauterine perfusion of G-CSF has a potential effect to increase the endometrial thickness in these patients; however, the rate of cancellation was still high and poor pregnancy outcomes were observed.

Efficacy of tocopherol and pentoxifylline combined therapy for women undergoing assisted reproductive treatment with poor endometrial development: a retrospective cohort study on 143 patients

Poor endometrial development during in vitro fertilization remains challenging. Indeed, no broadly accepted definition of poor endometrial development exists, and no treatment has shown any improvement in the condition. The aim of this study was to analyze whether treatment with a combination of pentoxifylline and tocopherol increases endometrial volume. This monocentric and retrospective study includes patients with previous miscarriages, in vitro fertilization failure, or poor endometrial development. The patients had an ultrasonography during the mid-luteal phase to assess both endometrial thickness and endometrial volume (EV). If the volume was less than 2 mL, they were given pentoxifylline (PTX) and tocopherol for at least 2 months before a second ultrasound assessment. One hundred and forty-four patients were analyzed. The mean duration of treatment was 132 days. The combination of tocopherol and PTX significantly increased the EV by 0.47 mL (p < 0.0001; 95% CI 0.38-0.57). The mean ± SD EV was 1.34 ± 0.38 mL and 1.82 ± 0.63 mL before and after the treatment respectively. No data concerning pregnancy rates were interpretable. We showed an improvement of poor endometrial proliferation with a treatment including PTX and tocopherol. These promising results should be followed up by a prospective study.

Effects of autologous platelet-rich plasma on endometrial expansion in patients undergoing frozen-thawed embryo transfer: A double-blind RCT

Background

Adequate endometrial growth is principal for implantation and pregnancy. Thin endometrium is associated with lower pregnancy rate in assisted reproductive technology. Some frozen-thawed embryo transfer cycles are cancelled due to inadequate endometrial growth.

Objective

To assess the effectiveness of autologous platelet-rich plasma (PRP) intrauterine infusion for the treatment of thin endometrium.

Materials and Methods

A total of 72 patients who had a history of cancelled frozen-thawed embryo transfer cycle due to the thin endometrium ( < 7mm) were assessed for the eligibility to enter the study between 2016 and 2017. Twelve patients were excluded for different reasons, and 60 included patients were randomly assigned to PRP or sham-catheter groups in a double-blind manner. Hormone replacement therapy was administered for endometrial preparation in all participants. PRP intrauterine infusion or shamcatheter was performed on day 11-12 due to the thin endometrium and it was repeated after 48 hr if necessary.

Results

Endometrial thickness increased at 48 hr after the first intervention in both groups. All participants needed second intervention due to an inadequate endometrial expansion. After second intervention, endometrial thickness was 7.21 ± 0.18 and 5.76 ± 0.97 mm in the PRP group and sham-catheter group, respectively. There was a significant difference between the two groups. (p < 0.001). Embryo transfer was done for all patients in PRP group and just in six cases in the sham-catheter group. Chemical pregnancy was reported in twelve cases in the PRP group and two cases in the sham-catheter group.

Conclusion

According to this trial, PRP was effective in endometrial expansion in patients with refractory thin endometrium.

Management of thin endometrium in assisted reproduction: a clinical practice guideline from the Canadian Fertility and Andrology Society

The impact and management of thin endometrium is a common challenge for patients undergoing assisted reproduction. The objective of this Canadian Fertility and Andrology Society (CFAS) guideline is to provide evidence-based recommendations using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) framework on the assessment, impact and management of thin endometrium in assisted reproduction. The effect of endometrial thickness on pregnancy and live birth outcomes in ovarian stimulation and IVF (fresh and frozen cycles) is addressed. In addition, recommendations on the use of adjuvants to improve endometrial thickness and pregnancy outcomes are provided.

Current clinical applications of platelet-rich plasma in various gynecological disorders: An appraisal of theory and practice

The purpose of this paper is to review the current clinical uses of platelet-rich plasma (PRP) in the field of gynecology. All relevant articles published from January 2000 to December 2017 were reviewed and analyzed. The articles on PRP in the field of gynecology were mainly case series, pilot studies, or case reports. PRP is currently considered a new therapeutic modality for some disorders that are refractory to conventional drugs.

Six-month recovery needed after dilation and curettage (D and C) for reproductive outcomes in frozen embryo transfer

In this study, the endometrial developmental and reproductive outcomes of frozen embryo transfers (FETs) which were performed subsequent to miscarriages managed by dilation and curettage (D and C) were investigated. The intracytoplasmic sperm injection (ICSI) blastocyst freeze-all cycles performed between January 2014 and August 2016 were screened for the patients who had undergone their FET (first), miscarriages (>5 < 14 weeks), D and C, and the patients who had undergone their FET (second) (study group; n = 71); and patients who underwent FET (1st), a chemical pregnancy loss (PL) (<5 weeks) and FET (2nd) (reference group; n = 38). The live births (LB; delivery >20 weeks) of FET (2nd) were analysed in two time-interval sub-groups: ≤6 months or >6 months. In the study and reference groups, the median endometrial thickness at the second FET of the ≤6 months sub-groups was found to be significantly reduced. The relative risk for LB was significantly higher (1.65 [0.994-2.723] p = .043) in the >6 months study sub-group, with a lower risk for PL (0.62 [0.268-1.427] p = .329), whereas, there were no significant differences between the reference sub-groups. The management of miscarriage with D and C results in a significant and transient decrease in reproductive function in subsequent FET. Impact Statement What is already known on this subject? Approximately, 15-30% of positive pregnancies in assisted reproductive technology (ART) end in biochemical pregnancy losses (PLs) or miscarriages. Cervical dilation with suction or blunt curettage (D and C), has been the procedure most often used to manage the retained products of conception (RPOC) after miscarriage. Intrauterine surgery has the potential to directly affect reproduction, depending on the endometrial impact. What the results of this study add? The endometrium after D and C surgery may require 6 months to recover normal reproductive function, in terms of both live birth and PL. The extent of the damage to endometrial function is not found to be reflected in the endometrial thickness. What the implications are of these findings for clinical practice and/or further research? Patients who undergo miscarriage after their ART treatment may need to delay further treatment for 6 months to optimise their chances of LB. Alternative miscarriage management procedures need to be investigated; procedures that have lower risks for an adverse reproductive function and allow for shorter time intervals between treatments.

Transparent collaboration between industry and academia can serve unmet patient need and contribute to reproductive public health

The pharmaceutical and device industry has greatly contributed to diagnostic and therapeutic approaches in reproductive medicine in a very highly regulated environment, ensuring that development and manufacturing follow the highest standards. In spite of these achievements, collaboration between industry and physicians/academia is often presented in a negative context. However, today more than ever, partnership between industry and academia is needed to shorten the timeline between innovation and application, and to achieve faster access to better diagnostics, drugs and devices for the benefit of patients and society, based on complementary knowledge, skills and expertise. Such partnerships can include joined preclinical/clinical and post-marketing research and development, joint intellectual property, and joint revenue. In Europe, the transparency of this collaboration between pharmaceutical industry and medical doctors has been made possible by the Compliance and Disclosure Policy published by the European Federation of Pharmaceutical Industries and Associations (EFPIA), which represents the major pharmaceutical companies operating in Europe, and includes as members some but not all companies active in infertility and women's health. Under the EFPIA Disclosure Code of conduct, companies need to disclose transfers of value including amounts, activity type and the names of the recipient Health Care Professionals and Organizations. EFPIA member companies have also implemented very strict internal quality control processes and procedures in the design, statistical analysis, reporting, publication and communication of clinical research, according to Good Clinical Practice and other regulations, and are regularly inspected by competent authorities such as the US Food and Drug Administration (FDA) or European Medicines Agency (EMA) for all trials used in marketing authorization applications. The risk of scientific bias exists not only in the pharmaceutical industry but also in the academic world. When academics believe in a hypothesis, they may build their case by emphasizing the arguments supporting their case, and either refute, refuse, oppose or ignore arguments that challenge their assumptions. A possible solution to reduce this bias is international consensus on study design, data collection, statistical analysis and reporting of outcomes, especially in the area of personalized reproductive medicine, e.g. to demonstrate superiority or non-inferiority of personalized ovarian stimulation using biomarkers. Equally important is that declarations of interest are reported transparently and completely in scientific abstracts and publications, and that ghost authorship is replaced by proactive and clear co-authorship for experts from industry where such co-authorship is required based on the prevailing ICMJE criteria. In that context, however, reviewers should stop believing that publications by industry authors only, or by mixed groups of co-authors from industry and academia, are more prone to bias than papers from academic groups only. Instead, the scientific quality of the work should be the only relevant criterion for acceptance of papers or abstracts, regardless of the environment where the work was done. In the end, neutrality does not exist and different beliefs and biases exist within and between healthcare professionals and organizations and pharmaceutical industries. The challenge is to be transparent about this reality at all times, and to behave in an informed, balanced and ethical way as medical and scientific experts, taking into account compliance and legal regulations of both industry and academic employers, in the best interest of patients and society.

Platelet-rich plasma therapy and reproductive medicine

Reports on clinical uses of platelet-rich plasma (PRP) have dramatically increased in the last decade. Indications for PRP therapy range from muscle and skeletal injuries to hair re-growth. More recently evidences have shown its positive effects in promoting endometrial and follicular growth and gestation in assisted reproduction cycles. We discuss the putative role of PRP on endometrial receptivity, with a brief history of its applications in research and clinical therapies. Despite its widespread uses in medicine, the mechanisms through which PRP exerts its regenerative effects are only postulated, not based on scientific data. There is an unmet need for advanced research to corroborate present findings in the clinical scenario.

Platelet-rich plasma as an adjuvant in the endometrial preparation of patients with refractory endometrium

OBJECTIVE

To improve endometrial quality and implantation rates after the administration of platelet-rich plasma in patients with refractory endometrium.

METHODS

19 patients undergoing in vitro fertilization, aged between 33 and 45 years with a history of refractory endometrium, to whom platelet rich plasma was given by infusion with a catheter into the uterine cavity on the tenth day of the hormone replacement therapy, and then 72 hours after the first administration.

RESULTS

Endometrial thicknesses >7mm was reported with the first use; and in all cases, endometrial thicknesses >9mm were evident after the second administration. The entire study group qualified for Embryo Transfer at the blastocyst stage. We had 73.7% of positive pregnancy tests, of which 26.3% yielded live births; 26.3% ongoing pregnancies; 10.5% biochemical pregnancies; 5.3% anembryonic pregnancies and 5.3% had fetal death (16 weeks).

CONCLUSIONS

Platelet-rich plasma and its biostimulation effects on the endometrial microvasculature seems to be beneficial to patients with refractory endometrium, providing an increase in endometrial receptivity and a consequent increase in implantation rates. As an autologous resource, they are easy to obtain and inexpensive. Thus, we recommend it to be included in the different protocols for endometrial preparation, including those in which a natural cycle is preferred.

Autologous Intrauterine Platelet-Rich Plasma Instillation for Suboptimal Endometrium in Frozen Embryo Transfer Cycles: A Pilot Study

Introduction:

This pilot study was to evaluate the effectiveness of intrauterine infusion of autologous platelet-rich plasma (PRP) in infertile women undergoing frozen embryo transfer cycles with suboptimal endometrium.

Material and Methods:

Intrauterine instillation of autologous PRP was done in 68 women between 22 and 40 years, over 8 months, with suboptimal endometrial growth, and patients with repeated cycle cancellations, in addition to Estradiol valerate. Frozen embryo transfer was performed when the endometrium reached an optimal pattern in terms of thickness, appearance, and vascularity.

Results:

The mean pre-PRP endometrial thickness (ET) was 5 mm which significantly increased to 7.22 mm post-PRP. There was a significant increase in vascularity, seen by the number of vascular signals seen on Power Doppler, reaching the zones 3 and 4 of the endometrium. The positive beta Human Chorionic Gonadotropin (hCG) rate was 60.93% and the clinical pregnancy rate was 45.31%. A total of 13 women are in the second trimester, 13 are in the first trimester with a healthy intrauterine pregnancy, one patient had an ectopic gestation, three had blighted ova, two had missed abortions, and two biochemical pregnancies.

Conclusion:

This study suggests that the use of autologous PRP holds promise in the treatment of women with suboptimal ET and vascularity for embryo transfer. It would help to reduce the incidence of cycle cancellations and thus even help reduce the financial and psychological burden of repeated cancelled cycles.