Cell therapy in female infertility-related diseases: Emphasis on recurrent miscarriage and repeated implantation failure

Correlation between viral infections in male semen and infertility: a literature review

Infertility affects approximately one-sixth of couples globally, with the incidence of male infertility steadily increasing. However, our understanding of the impact of viral infections on fertility remains limited. This review consolidates findings from previous studies, outlining 40 viruses identified in human semen and summarizing their key characteristics, modes of transmission, and their effects on both the reproductive and endocrine systems. Furthermore, it elucidates potential pathogenic mechanisms and treatment prospects of viruses strongly associated with male infertility. This synthesis will enhance our comprehension of how viral infections influence male reproductive health, offering valuable insights for future research as well as the diagnosis and treatment of infectious infertility.

The Association Between the Maternal Pre-pregnancy Platelet Count and Fecundability in Mainland China: A Population-based Cohort Study

BACKGROUND

Currently, awareness about platelet count (PC) and its consequences for perinatal outcome have increased, but there is little reliable evidence on fecundability.

METHODS

Based on the National Free Pre-conception Check-up Projects supported by the Chinese government, 5,524,886 couples met the inclusion criteria and were included in this cohort study. Cox regression models were adopted to estimate fecundability ratios (FRs) and their 95% confidence intervals (CIs) for pre-pregnancy PC quintiles. Restricted cubic splines were used to flexibly model and visualize the relationship of PC with FRs. Microsoft SQL server and R software were used for data management and analysis.

RESULTS

The median of pre-pregnancy PC among women was 221.00 × 109/L. The first (<177.00 × 109/L) and second quintile (177.00-207.99 × 109/L) of PC showed slightly increased fecundability (Q1: adjusted FR 1.05; 95% CI, 1.04-1.06; Q2: adjusted FR 1.04; 95% CI, 1.03-1.05), while higher quintals (Q4: 236.00-271.99 × 109/L; Q5: ≥272.00 × 109/L) were related to reduction of fecundability, when compared with the third quintile of PC (208.00-235.99 × 109/L) (Q4: adjusted FR 0.96; 95% CI, 0.95-0.97; Q5: adjusted FR 0.88; 95% CI, 0.87-0.89). In the first quintiles (<177.00 × 109/L), only 20.93% women had PC below 129.94 × 109/L. An inverse-U-shaped association was consistently observed among women such that the lower PC within the normal range (<118.03 × 109/L) and higher PC (>223.06 × 109/L) were associated with the risk of reduced female fecundability (P for non-linearity < 0.01).

CONCLUSION

PC is associated with female fecundability. Further classification of PC levels may deepen our understanding of the early warnings and significance of female fecundability.

The effect of ovarian response parameters and the synergistic effect of assisted reproduction of poor ovarian response treated with platelet rich plasma: systematic review and meta-analysis

BACKGROUND

Poor ovarian response (POR) patients often encounter cycle cancellation and egg retrieval obstacles in assisted reproductive technology. Platelet rich plasma (PRP) ovarian injection is a potential treatment method, but the treatment methods are different, and the treatment results are controversial.

OBJECTIVE

This study adopts a systematic review and meta-analysis method based on clinical research to explore the efficacy and safety of PRP injection on POR.

METHOD

The following databases were searched for research published before March 2023; Medline (via PubMed), Web of Science, Scopus, Cochrane Library, Embase, Cochrane Library, and China National Knowledge Infrastructure Database (CNKI). The literature was then screened by two independent researchers, who extracted the data and evaluated its quality. Research was selected according to the inclusion criteria, and its quality was evaluated according to the NOS standard Cohort study. The bias risk of the included study was assessed with STATE 14.0. RevMan 5.3 software was used for meta-analysis.

MAIN RESULTS

Ten studies were included in the analysis, including 7 prospective cohort studies and 3 retrospective studies involving 836 patients. The results showed that after PRP treatment, follicle stimulating hormone (FSH) significantly decreased and anti-Mueller hormone (AMH) and luteinizing hormone (LH) significantly increased in POR patients, but estradiol did not change significantly; The number of antral follicles increased, and the number of obtaining eggs and mature oocytes significantly increased; The number of Metaphase type II oocytes, 2PN and high-quality embryos, and cleavage stage embryos significantly increased. In addition, the patient cycle cancellation rates significantly decreased. The rate of natural pregnancy assisted reproductive pregnancy and live birth increased significantly. Four reports made it clear that no adverse reactions were observed.

CONCLUSION

PRP may have the potential to improve pre-assisted reproductive indicators in POR patients, increase the success rate of in vitro fertilization-embryo transfer (IVF-ET) in POR patients, and improve embryo quality, and may be beneficial to the pregnancy outcome. There is no obvious potential risk in this study, but further clinical support is still needed.

The Effect of Granulocyte Colony-Stimulating Factor on Endometrial Receptivity of Implantation Failure Mouse

The purpose of this study was to investigate the effect of G-CSF on the endometrial receptivity of implantation failure mice. Sixty female mice were treated mifepristone to establish an implant failure model. The treatment groups received different doses of G-CSF. Endometrial tissue and serum were collected on day 5 after mating. The abundance of pinopodes on the endometrium was observed by scanning electron microscopy. The expressions of LPAR3, COX2, and HOXA10 were detected by RT-qPCR and Western blotting. Serum levels of E2, P, VEGF, LIF, TNF-α and IL-10 were measured by ELISA. The expressions of VEGF, CD34, CD57, TNF-α, and IL-10 were assessed by immunohistochemistry. Immunofluorescence analysis was performed to determine the number of CD57, Treg, and Th17 cells. G-CSF increased implantation and pregnancy rates of mifepristone-induced implantation failure mice, with the most significant effect seen at the intermediate dose. G-CSF increased the serum levels of E2 and P, the abundance of endometrial pinopodes, and the level of LIF in the endometrium. It also promoted the expression of VEGF, HOXA10, LPAR3, and COX2. Moreover, G-CSF reduced the level of CD57 cells and the ratio of Th17/Treg cells in endometrium. G-CSF reduced the inflammatory factor TNF-α, but IL-10 did not change significantly. G-CSF can enhance embryo implantation rate and pregnancy rate and improve endometrial receptivity by attenuating degeneration of pinopodes, upregulating estrogen and progesterone, facilitating angiogenesis, maintaining immune cell homeostasis, and reducing the production of inflammatory cytokines in implantation failure mouse.

The evaluation of PD-1 and Tim-3 expression besides their related miRNAs in PBMCs of women with recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is a multifactorial disorder, associated with immunologic abnormalities. During pregnancy, the maternal immune system uses different tolerance mechanisms to deal with a semi-allogenic fetus. The expression of immune checkpoints and their related miRNAs in immune cells can ensure pregnancy at the feto-maternal interface by modulating immune responses. This study aims to evaluate the expression of the immune checkpoint molecules PD-1 and Tim-3 on circulating T cells by flow cytometry, that of mir-138 and mir-155 in PBMCs by Real-time PCR, and the concentrations of TGF-β and IP-10 in the sera of women suffering from RPL as well as of gestational age-matched healthy pregnant women by ELISA. The percentage of PD-1 or Tim-3 expressing CD8+ T cells was significantly lower in RPL patients compared to the controls, while there was no significant difference in Tim-3 expression of CD4+ T cells between the two groups. The mRNA of both the PD-1 and Tim-3 genes were downregulated in PBMCs of RPL patients compared to controls, however, the difference was not statistically significant for Tim-3. The concentration of TGF-β was significantly lower and that of IP-10 was significantly higher in the sera of RPL patients than in those of the controls. The relative expression of mir-138 and miR-155 were significantly lower, in PBMCs of RPL patients than in those of healthy pregnant women. These data confirm that by affecting cytokine production, immune checkpoints, and microRNAs play a role in establishing the appropriate local immune environment for successful pregnancy. The wider analysis of immune checkpoints may also yield new biomarkers for the diagnosis and prevention of RPL.

lncRNA TTTY14 participates in the progression of repeated implantation failure by regulating the miR-6088/SEMA5A axis

PURPOSE

To identify potential biomarkers and the molecular mechanisms associated with repeated implantation failure (RIF), three microarray datasets, GSE71331 (lncRNA + mRNA), GSE111974 (lncRNA + mRNA), and GSE71332 (miRNA), were retrieved from the Gene Expression Omnibus (GEO) database.

METHODS

The differentially expressed mRNAs (DEMs), lncRNAs (DElncRNAs), and miRNAs (DEmiRNAs) between normal control samples (C group) and RIF samples (RIF group) were identified, and then a module partition analysis was performed based on weighted correlation network analysis (WGCNA). Following enrichment analysis of the genes, the lncRNA-miRNA-mRNA interactions (ceRNA) were examined. The mRNAs in the ceRNA network were evaluated using the GSE58144 dataset. Finally, the key RNAs were verified using reverse transcription-quantitative polymerase chain reaction (RT-qPCR).

RESULTS

Fifty-three DEmiRNAs, 327 DEMs, and 13 DElncRNAs were identified between the C and RIF groups. According to WGCNA, the magenta module was positively correlated with RIF disease status. The lncRNA-mRNA interaction analysis based on genes in the magenta module revealed the intersecting lncRNAs, including peptidylprolyl isomerase E-like pseudogene (PPIEL) and the testis-specific transcript, y-Linked 14 (TTTY14); these lncRNAs are mainly involved in functions, such as plasma membrane organization. The ceRNA network analysis revealed several interactions, such as TTTY14-miR-6088-semaphorin 5 A (SEMA5A). Finally, SEMA5A and the zinc finger protein 555 (ZNF555) were identified to be significantly upregulated in the RIF group compared with those in the C group in the GSE58144 dataset. The RT-qPCR results aligned with the above results.

CONCLUSIONS

Overall, TTTY14, ZNF555, SEMA5A, PPIEL, and miR-6088 could serve as novel biomarkers of RIF.

Association between different insulin resistance surrogates and infertility in reproductive-aged females

BACKGROUND

Obesity and metabolic syndrome are observed more frequently in infertile women, and insulin resistance (IR) is closely related to them. However, there are no studies that have examined the association between different IR surrogates and female infertility, hence we investigated the potential association between them in the general population.

METHODS

This was a cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES, 2013-2018). The association of different IR surrogates (HOMA-IR index, TyG index and TyG-BMI index) with female infertility was estimated by multivariable regression analysis.

RESULTS

After adjusting for confounders, the HOMA-IR index and TyG index did not show an association with female infertility, while the TyG-BMI index was found to have a positive association with female infertility (OR = 1.01, 95% CI: 1.00, 1.01; P < 0.0001), and the OR of the TyG-BMI group T3 (≥ 255.55) was significantly different compared to the group T1 (< 185.31) (OR = 3.02, 95% CI: 1.62, 5.60). Similar results were seen in most of the subgroup participants by stratified analysis (P-interaction > 0.05). However, different IR surrogates did not show variability in their ability to predict infertility [TyG-BMI: 0.68 (95% CI: 0.62, 0.74) vs. TyG: 0.62 (95% CI: 0.57, 0.68) vs. HOMA-IR: 0.65 (95% CI: 0.60, 0.71)].

CONCLUSIONS

Our result suggests that high levels of TyG-BMI index were positively associated with female infertility in US reproductive-aged females.

TiO2 nanoparticles combined with polystyrene nanoplastics aggravated reproductive toxicity in female mice via exacerbating intestinal barrier disruption

BACKGROUND

TiO2 nanoparticles (NPs), a widely used food additive in the food industry, have been shown to aggravate the progress of metabolic diseases. Nanoplastics (NPLs) are an emerging contaminant widely present in the food system and have been shown to induce ovarian disorders in mammals. Noteworthy, they can be ingested by humans through 'contaminated' food, whereas the potential toxicity of NPLs and TiO2 NPs combined remains unclear. In the present study, we investigated the potential effects and mechanisms of co-exposure to polystyrene (PS) NPLs and TiO2 NPs on the ovary in female mice.

RESULTS

Our results revealed that the co-exposure of TiO2 NPs and PS NPLs caused significant injury to ovarian structure and function, but individual exposure had no effect. Moreover, compared to the TiO2 NPs group, co-exposure aggravated the intestinal barrier damage in mice, increasing the bioaccumulation of TiO2 NPs in the ovary. After being supplemented with the oxidative stress inhibitor N-acetyl-l-cysteine, the expression of ovarian antioxidant genes increased, and the ovarian structural and functional injury in co-exposure mice reverted to normal levels.

CONCLUSION

The present study demonstrated that co-exposure to PS NPLs and TiO2 NPs can cause more severe female reproductive dysfunction and deepens the toxicological insights between NPLs and NPs. © 2023 Society of Chemical Industry.

Time-restricted feeding ameliorates uterine epithelial estrogen receptor α transcriptional activity at the time of embryo implantation in mice fed a high-fat diet

BACKGROUND

More than 30% of reproductive-age women are obese or overweight. Obesity and exposure to a high-fat diet (HFD) detrimentally affect endometrial development and embryo implantation. We previously reported that time-restricted feeding (TRF) improved ovarian follicular development, but whether and how TRF modulates embryo implantation are poorly understood.

OBJECTIVE

We investigated the effect of TRF on embryo implantation.

METHODS

In TRF group, mice had 10 hours of food free access from 9 pm to 7 am, and fed a normal diet or a HFD. Tail vein injection of Chicago blue dye was used to examine embryo implantation sites at day 5.5 (D5.5) of pregnancy. Serum collected at D0.5 and D4.5 of pregnancy was used to examine the level of estradiol (E2) and progesterone. Uterine estrogen receptor (ER) and progesterone receptor levels and their targeted aquaporins (AQPs) were measured. LC-MS was used to analyze bile acid (BA) composition, and primary hepatocytes were used to test the effects of BA on the expression level of SULT1E1, a key enzyme in estrogen inactivation and elimination.

RESULTS

We found that TRF prevented HFD-induced embryo loss and alleviated the defect in luminal closure on D4.5 of pregnancy. The cyclic changes of E2 level were lost in mice fed ad libitum but not in TRF mice on the HFD. The HFD increased ERα expression and transcriptional activity, which induced AQP3 and AQP5 expression on D4.5 of pregnancy. TRF prevented the negative effect of the HFD on uterine luminal closure. Furthermore, in vitro and in vivo results showed that BA suppressed estrogen degradation by activating liver SULT1E1 expression.

CONCLUSIONS

Our findings demonstrated that TRF prevented HFD-induced defects in luminal closure, thereby improving embryonic implantation, and provide novel insights into the effects of dietary intervention on obesity and associated infertility.

Exosome- based technologies as a platform for diagnosis and treatment of male and female infertility-related diseases

Nowadays, infertility related diseases become one of the basic challenges in societies. Human fertilization and fetal development are one of the most complex biological process, influenced by various factors, such as exosomes. Exosomes are Nano-sized bilayer-lipid membrane vesicles that play a role in mediating cell to cell communication in the reproductive system by serving as carriers of different biomolecules. Alterations in exosomes number and contents also can be seen in different male and female reproductive diseases in animals and human cases. These nanoparticles have great potential to become a large-scale therapeutic platform in the field of regenerative medicine. Diagnostic and therapeutic properties of exosomes have opened new windows of hope for using these compounds in the diagnosis and treatment of many diseases, especially pregnancy disorders. Various methods including direct injection, intravenous injection, intraperitoneal injection, oral administration, and hydrogel-based encapsulation for targeted delivery of exosomes have been investigated in different disease models. The most recent advances in the development of exosome-functionalized biomaterials that mediate enhanced preservation exosome bioactivity and controlled release, have been presented. This review highlights the potential medical applications of exosomes with emphasis on diagnostic and therapeutic effects of exosomes on male and female reproductive system related diseases. In addition, the advantages of the biomaterial-based exosome delivery systems have been examined in this review.

The immunomodulatory effect of intradermal allogeneic PBMC therapy in patients with recurrent spontaneous abortion

BACKGROUND

There has been limited study on the impact of PBMC therapy in RSA patients with immunological disorders such as Th17 and Treg cell dysregulation, as well as their associated factors. This study aimed to assess the efficacy of PBMC therapy in modulating immune cell frequency, cytokine production, transcription factors, and miRNAs implicated in the regulation of their function, as well as their potential superiority to routine treatments.

METHODS

Fifty RSA women who had received PBMCs and 50 matched-paired control RSA women who had received the routine treatments were recruited and followed for three months. The frequencies of Th17, Treg, NK, and B cells were assessed using flow cytometry. Thereafter, the gene expression level of the transcription factors and related miRNAs of Treg cell and Th17 cell was quantified using RT-PCR. Then ELISA was employed to assess the cytokine production of Th17 and Treg cells. Finally, the live birth rate and miscarriage rate were evaluated as clinical outcomes in this study.

RESULTS

Flow cytometry analysis revealed that PBMC therapy significantly reduces the frequencies of Th17 and NK cells while enhancing the frequency of Treg cells. RT-PCR analysis confirmed that PBMC therapy significantly downregulates RORγt and upregulates FoxP3. Likewise, RT-PCR analysis showed that PBMC therapy reduces the expression of miR-25, miR-155, and miR-326 while increasing the expression of miR-10a. ELISA results demonstrated that PBMC therapy considerably decreases the concentration of inflammatory cytokines IL-1β, IL-17, and TNF-α and enhances the concentration of anti-inflammatory cytokines IL-10 and TGF-β. Following PBMC therapy live birth rate raised while miscarriage rate reduced.

CONCLUSION

Our findings suggested that, in contrast to routine treatments, PBMC therapy can significantly modulate the maternal immune system by enhancing the Treg/Th17 paradigm and regulating the expression of Treg and Th17 cell-associated cytokines, transcription factors, and miRNAs. This treatment also can increase the live birth rate in RSA patients.

Decreased CD44v3 expression impairs endometrial stromal cell proliferation and decidualization in women with recurrent implantation failure

BACKGROUND

The precise pathogenesis of poor endometrial receptivity in recurrent implantation failure (RIF) remains unclear. This study was aimed at exploring the effects of different CD44 isoforms in the mid-secretory phase endometrium on endometrial receptivity in women with RIF.

METHODS

Mid-secretory phase endometrial tissue samples were obtained from the following two groups of women who had undergone IVF: (a) 24 patients with RIF and (b) 18 patients with infertility due to tubal obstruction, who had achieved a successful clinical pregnancy after the first embryo transfer in IVF (control group). Identification of differentially expressed CD44 isoforms in endometrial tissues was assessed using immunohistochemistry, qPCR, and western blotting. Effects of overexpression and knockdown of CD44v3 on proliferation and decidualization of immortalized human endometrial stromal cells (T-HESCs) and primary HESCs were investigated by qPCR and western blot analysis. A heterologous coculture system of embryo implantation was constructed to mimic the process of trophoblast invasion during implantation.

RESULTS

The expression of CD44v3 was significantly higher in the mid-secretory phase of endometrial stromal cells than in the proliferation phase, but was notably lower in RIF patients. Knockdown of CD44v3 significantly downregulated cell proliferation both in T-HESCs and HESCs. The expression of decidualization markers, prolactin (PRL) and insulin like growth factor binding protein-1 (IGFBP1), was notably decreased following the knockdown of CD44v3, whereas the expression of both PRL and IGFBP1 increased after its overexpression in HESCs. Furthermore, the CD44v3-knockdown HESCs displayed significant deficiency in supporting trophoblast outgrowth in a coculture system of embryo implantation; however, overexpression of CD44v3 in HESCs promoted trophoblast outgrowth.

CONCLUSION

The reduced expression of CD44v3 suppresses the proliferation and decidualization of HESCs, which might play a pivotal role in poor endometrial receptivity in women with RIF.

Efficacy of Autologous Intrauterine Infusion of Platelet-Rich Plasma in Patients with Unexplained Repeated Implantation Failures in Embryo Transfer: A Systematic Review and Meta-Analysis

(1) Background: Controversial conclusions have been made in previous studies regarding the influence of autologous platelet-rich plasma (PRP) in the reproductive outcomes of women with repeated implantation failures (RIF) who are undergoing embryo transfer (ET). (2) Methods: This study aimed to evaluate the effect of PRP intrauterine infusion in patients with unexplained RIF, who are undergoing in vitro fertilization (IVF) or intracytoplasmic injection (ICSI), by a systematic review and meta-analysis. (3) Results: A fixed-effects model was used, and 795 cases and 834 controls were included in these studies. The pooling of the results showed the beneficial effect of PRP which were compared with those of the control in terms of the clinical pregnancy rates (n = 10, risk ratio (RR) = 1.79, 95% confidence intervals (CI): 1.55, 2.06; p < 0.01, I2 = 40%), live birth rates (n = 4, RR = 2.92, 95% CI: 2.22, 3.85; p < 0.01, I2 = 83%), implantation rates (n = 3, RR = 1.74, 95% CI: 1.34, 2.26; p < 0.01, I2 = 0%), and positive serum β-HCG 14 days after the ET (n = 8, RR = 1.77, 95% CI: 1.54, 2.03; p < 0.01, I2 = 36%). However, we did not find that the miscarriage rates indicated a significant difference between the two groups (n = 6, RR = 1.04, 95% CI: 0.72, 1.51; p = 0.83, I2 = 0%). (4) Conclusions: The findings of this systemic review and meta-analysis suggest that PRP appears to improve the results of IVF/ICSI treatments in the cases of unexplained RIF.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles Carrying MicroRNA-29a Improves Ovarian Function of Mice with Primary Ovarian Insufficiency by Targeting HMG-Box Transcription Factor/Wnt/β-Catenin Signaling

Background

Primary ovarian insufficiency (POI) is a female disease characterized by ovarian function loss under 40 years old. Transplantation of exosomes is an encouraging regenerative medicine method that has the potential for restoring ovarian functions post-POI with high efficiency. Therefore, we investigate the therapeutic efficacy and potential mechanisms of human umbilical cord mesenchymal stem cell- (UCMSC-) derived exosomes on ovarian dysfunction post-POI.

Methods

The model of POI was established by intraperitoneal injection with 5 mg/kg cisplatin. The mouse ovarian function was detected by measuring the levels of anti-Mullerian hormone, follicle-stimulating hormone, and estradiol and detecting the morphological changes. For in vitro experiments, the characterization and identification of UCMSCs and UCMSC-derived exosomes were done by observation of morphologies and flow cytometry. To exclude the interference effect of nonspecific precipitation substances, UCMSCs were treated with RNase A or RNase A in combination with Triton X-100. Granulosa cell (GC) identification was performed using immunofluorescence. GC proliferation and viability were assessed using 5-ethynyl-2′-deoxyuridine (EdU) assays and Cell Counting Kit-8 (CCK-8), and GC apoptosis was calculated by flow cytometry. Gene expression and protein levels were evaluated using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting. The binding relationship between miR-29a and HMG-box transcription factor (HBP1) was verified by luciferase reporter assays.

Results

In vitro, the human UCMSC-derived exosomes carrying miR-29a upregulation promoted the proliferation of GCs and suppressed their apoptosis. In vivo, miR-29a upregulation reserved the mature follicles and restored the ovarian functions. miR-29a targeted HBP1 and negatively regulated its expression. HBP1 upregulation rescued the miR-29a upregulation-induced inhibition in GC apoptosis and inactivated the Wnt/β-catenin pathway.

Conclusion

The exosomal miR-29a derived from human UCMSCs improves the ovarian function by targeting HBP1 and activating the Wnt/β-catenin pathway.

Correlation of TNF-α, IFN-γ and TGF-β Expression with In-vitro Fertilization Success Rates in Women with Recurrent Implantation Failure Undergoing Treatment with Intra-lipid Infusion

This study aimed at assessing the correlations between gene expression of TNF-a, IFN-g, TGF-β in peripheral lymphocytes from women suffering from repeated implantation failure before and after intravenous Intra-lipid (IL) therapy, and correlation between changes in gene expression with IL infusion and success rate of IVF cycles. Twenty-three women complaining of unexplained infertility without history of autoimmune disorders, or immunodeficient diseases were included. All women included aged <40 years, BMI <28 with history of recurrent IVF cycles failure, seeking medical advice for new IVF trial. All were average responders to induction of ovulation (≥5 oocytes in each cycle) with good quality embryos transferred to uterus at proper time. Included women received 200 ml of 10% IL slowly intravenous. Two venous blood samples were taken from all candidates, one before IL infusion and the second was at day of embryo transfer. The current study detected a significant reduction of expression in TNF-a and increased expression of TGF-β, while non-significant reduction in expression of IFN-g after treatment. Significant associations between reduction of TNF-α, IFN-g expression and positive clinical and ongoing pregnancy were observed, while increased TGF-β expression was associated with only positive ongoing pregnancy. In conclusion, IL therapy might have a positive impact on IVF pregnancy rates via alterations in peripheral cytokines expression mainly reduction of TNF-a mRNA expression and increased TGF-b mRNA expression.

Allogeneic lymphocytes immunotherapy in female infertility: Lessons learned and the road ahead

The endometrium is an essential tissue in the normal immunologic dialogue between the mother and the conceptus, which is necessary for the proper establishment and maintenance of a successful pregnancy. It's become evident that the maternal immune system plays a key role in the normal pregnancy's initiation, maintenance, and termination. In this perspective, the immune system contributes to regulating all stages of pregnancy, thus immunological dysregulation is thought to be one of the major etiologies of implantation failures. Many researchers believe that immune therapies are useful tactics for improving the live births rate in certain situations. Lymphocyte immunotherapy (LIT) is an active form of immunotherapy that, when used on the relevant subgroups of patients, has been shown in multiple trials to dramatically enhance maternal immunological balance and pregnancy outcome. The primary goal of LIT is to regulate the immune system in order to create a favorable tolerogenic immune milieu and tolerance for embryo implantation. However, there are a plethora of influential factors influencing its therapeutic benefits that merit to be addressed. The objective of our study is to discuss the mechanisms and challenges of allogeneic LIT.

Prognostic significance and therapeutic potentials of immune checkpoints in osteosarcoma

Although there exist manifold strategies for cancer treatment, researchers are obliged to develop novel treatments based on the challenges that arise. One of these recent treatment approaches is cancer immunotherapy, which enjoys various types of strategies itself. However, one of the most significant methods, in this regard, is employing immune checkpoint proteins (ICPs). Bone sarcomas have several subtypes, with the most common ones being chordoma, chondrosarcoma, Ewing sarcoma, and osteosarcoma. Although many aggressive treatment approaches, including radiotherapy, chemotherapy, and surgical resection, have been employed over the last decades, significantly improved outcomes have not been observed for Ewing sarcoma or osteosarcoma patients. Additionally, chordoma and chdrosarcoma resist against both radiation and chemotherapy. Accordingly, elucidating how recent therapies could affect bone sarcomas is necessary. Checkpoint inhibitors have attracted great attention for the treatment of several cancer types, including bone sarcoma. Herein, the recent advances of current immune checkpoint targets, such as anti-PD-1/PD-L1 and anti-CTLA-4 blockade, for the treatment of bone sarcoma have been reviewed.

Cell-based therapy in thin endometrium and Asherman syndrome

Numerous treatment strategies have so far been proposed for treating refractory thin endometrium either without or with the Asherman syndrome. Inconsistency in the improvement of endometrial thickness is a common limitation of such therapies including tamoxifen citrate as an ovulation induction agent, acupuncture, long-term pentoxifylline and tocopherol or tocopherol only, low-dose human chorionic gonadotropin during endometrial preparation, aspirin, luteal gonadotropin-releasing hormone agonist supplementation, and extended estrogen therapy. Recently, cell therapy has been proposed as an ideal alternative for endometrium regeneration, including the employment of stem cells, platelet-rich plasma, and growth factors as therapeutic agents. The mechanisms of action of cell therapy include the cytokine induction, growth factor production, natural killer cell activity reduction, Th17 and Th1 decrease, and Treg cell and Th2 increase. Since cell therapy is personalized, dynamic, interactive, and specific and could be an effective strategy. Despite its promising nature, further research is required for improving the procedure and the safety of this strategy. These methods and their results are discussed in this article.

Methylation-reprogrammed CHRM3 results in vascular dysfunction in the human umbilical vein following IVF-ET

Assisted reproductive technology (ART) has been used globally among infertile couples. However, many epidemiological investigations have indicated that ART is associated with a range of long-term adverse health outcomes in offspring, including cardiovascular disease, obesity and increased plasma lipid levels. Until now, direct evidence has been limited regarding the pathological changes in vascular function in fetuses with ART. In this study, human umbilical cords were collected from healthy normal pregnancies and IVF-ET pregnancies. Vascular functional studies involving acetylcholine (ACh), antagonists of its specific receptors, and L-type calcium channel/PKC-MLC20 phosphorylation pathway specific inhibitors were conducted. Quantitative real-time PCR, Western blotting and methylation analyses were performed on umbilical vein samples. We found that the umbilical vein constriction induced by ACh in the IVF-ET group was significantly attenuated compared with that in the healthy normal pregnancy group, which was not only associated with the hypermethylation of ACh muscarinic receptor subtype 3 (CHRM3) and decreased expression of CHRM3, PKCβ and CaV1.2, but was also related to the reduced phosphorylation of MLC20. The present study revealed that the hypermethylation of CHRM3, leading to a reduction in CHRM3 expression and downregulation of the CaV1.2/PKC-MLC20 phosphorylation pathway, was responsible for the decreased sensitivity to ACh observed in the umbilical vein under IVF-ET conditions. The hypermethylation of CHRM3 caused by IVF-ET might play an important role in altered vasoconstriction and impact cardiovascular systems in the long run.

microRNAs in female infertility: An overview

Infertility impacts a considerable number of women worldwide, and it affects different aspects of family life and society. Although female infertility is known as a multifactorial disorder, there are strong genetic and epigenetic bases. Studies revealed that miRNAs play critical roles in initiation and development of female infertility related disorders. Early diagnosis and control of these diseases is an essential key for improving disease prognosis and reducing the possibility of infertility and other side effects. Investigating the possible use of miRNAs as biomarkers and therapeutic options is valuable, and it merits attention. Thus, in this article, we reviewed research associated with female diseases and highlighted microRNAs that are related to the polycystic ovary syndrome (up to 30 miRNAs), premature ovarian failure (10 miRNAs), endometriosis (up to 15 miRNAs), uterine fibroids (up to 15 miRNAs), endometrial polyp (3 miRNAs), and pelvic inflammatory (6 miRNAs), which are involved in one or more ovarian or uterine disease-causing processes.

The Role of Stem Cells and Their Derived Extracellular Vesicles in Restoring Female and Male Fertility

Infertility is a globally recognized issue caused by different reproductive disorders. To date, various therapeutic approaches to restore fertility have been attempted including etiology-specific medication, hormonal therapies, surgical excisions, and assisted reproductive technologies. Although these approaches produce results, however, fertility restoration is not achieved in all cases. Advances in using stem cell (SC) therapy hold a great promise for treating infertile patients due to their abilities to self-renew, differentiate, and produce different paracrine factors to regenerate the damaged or injured cells and replenish the affected germ cells. Furthermore, SCs secrete extracellular vesicles (EVs) containing biologically active molecules including nucleic acids, lipids, and proteins. EVs are involved in various physiological and pathological processes and show promising non-cellular therapeutic uses to combat infertility. Several studies have indicated that SCs and/or their derived EVs transplantation plays a crucial role in the regeneration of different segments of the reproductive system, oocyte production, and initiation of sperm production. However, available evidence triggers the need to testify the efficacy of SC transplantation or EVs injection in resolving the infertility issues of the human population. In this review, we highlight the recent literature covering the issues of infertility in females and males, with a special focus on the possible treatments by stem cells or their derived EVs.

Infertility and subsequent recurrent miscarriage: Current state of the literature and future considerations for practice and research

Background: Recurrent miscarriage (RM) and infertility are independently associated with adverse pregnancy outcomes, in addition to psychological sequelae. Experiencing pregnancy loss alongside infertility is particularly difficult. International guidance regarding RM is conflicting, and applicability to women with infertility is undetermined. The aim of this study was to: (i) establish if women/couples with a history of infertility are recognised in the literature on the investigation and management of RM, and (ii) determine if the specific needs of women/couples experiencing RM and infertility are ascertained and incorporated into clinical management strategies. Methods: We examined the wide-ranging literature to ascertain what gaps existed. Studies were retrieved through searches of PubMed and Google Scholar up to 21 January 2021 using appropriate controlled vocabulary and combinations of key words. No language or study design restrictions were applied. Results: While women/couples experiencing RM after infertility appear in studies evaluating investigations and proposed treatments, high-quality studies are lacking. Furthermore, they are largely excluded from international clinical guidance and qualitative research. Conclusions: The experiences of women/couples with RM and infertility and their specific care needs within maternity and fertility services are underexplored. It is unclear from current RM guidelines how best to manage and support this complex cohort. Women/couples with infertility and RM are underserved in the literature and in clinical guidance. Further robust studies are warranted to examine pregnancy outcomes, investigations and treatments currently used. Qualitative research is also required to identify their medical and psychological needs to better support this vulnerable group.

Transplantation of human umbilical cord mesenchymal stem cells to treat premature ovarian failure

As one of the problems and diseases for women before 40 years, premature ovarian failure (POF) could be characterized by amenorrhea, low estrogen levels, infertility, high gonadotropin levels, and lack of mature follicles. Causes of the disease involve some genetic disorders, autoimmunity diseases, and environmental factors. Various approaches have been employed to treat POF, however with limited success. Today, stem cells are used to treat POF, since they have the potential to self-repair and regenerate, and are effective in treating ovarian failure and infertility. As mesenchymal stem cell (MSC) could simultaneously activate several mechanisms, many researchers consider MSC transplantation to be the best and most effective approach in cell therapy. A good source for mesenchymal stem cells is human umbilical cord (HUCMSC). Animal models with cyclophosphamide are required for stem cell treatment and performance of HUCMSC transplantation. Stem cell therapy could indicate the levels of ovarian markers and follicle-stimulating hormone receptor. It also increases ovarian weight, plasma E2 levels, and the amount of standard follicles. Herein, the causes of POF, effective treatment strategies, and the effect of HUCMSC transplantation for the treatment of premature ovarian failure are reviewed. Many studies have been conducted in this field, and the results have shown that stem cell treatment is an effective approach to treat infertility.

Immune checkpoints and reproductive immunology: Pioneers in the future therapy of infertility related Disorders?

As co-stimulatory receptors, immune checkpoint molecules are found on the surface of various immune cells and transduce inhibitory signals following ligand binding. The most studied members in this regard include PD-1, TIM-3, and CTLA-4. The physiological part immune checkpoints possess is the prevention of dangerous immune attacks towards self-antigens throughout an immune response, which takes place through the negative regulation of the effector immune cells, through the induction of T-cell exhaustion, for instance. It has recently been suggested that each checkpoint reduces immunoactivation via distinct intracellular mechanisms of signaling. Regulators of immune checkpoints are supposed to participate actively in immune defense mechanisms against infections, preventing autoimmunity, transplantation, and tumor immune evasion. In pregnancy, as an active immunotolerance mechanism which is also natural, the maternal immune system encounters two simultaneous challenges; in addition to accepting the semi-allogeneic fetus, the maternal immune system should also prevent infections. In this regard, the part immune checkpoint molecules possess is particularly interesting. Herein, the current understanding of such part in reproductive immunology is described.

Proteomic and functional analysis of proteins related to embryonic development of decidua in patients with recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is defined as the loss of two or more consecutive pregnancies before the 20 weeks of gestation. Recurrent pregnancy loss affects about 1-2% of couples trying to conceive; however, the mechanisms leading to this complication are largely unknown. Our previous studies using comparative proteomics identified 314 differentially expressed proteins (DEPs) in the placental villous. In this study, we identified 5479 proteins from a total of 34,157 peptides in decidua of patients with early recurrent pregnancy loss (Data are available via ProteomeXchange with identifier PXD023849). Further analysis identified 311 DEPs in the decidua tissue; and 159 proteins were highly expressed while 152 proteins were lowly expressed. These 311 proteins were further analyzed by using Ingenuity Pathway Analysis (IPA). The results suggested that 50 DEPs played important roles in the embryonic development. Upstream analysis of these DEPs revealed that AGT was the most important upstream regulator. Furthermore, protein - protein interaction (PPI) analysis of the embryonic development DEPs from the placental villous and decidua was performed in the STRING database. This study identified several proteins specifically associated with embryonic development in decidua of patients with early recurrent pregnancy loss. Therefore, these results provide new insights into potential biological mechanisms, that may ultimately inform recurrent pregnancy loss.

A Review on Microfluidics: An Aid to Assisted Reproductive Technology

Infertility is a state of the male or female reproductive system that is defined as the failure to achieve pregnancy even after 12 or more months of regular unprotected sexual intercourse. Assisted reproductive technology (ART) plays a crucial role in addressing infertility. Various ART are now available for infertile couples. Fertilization in vitro (IVF), intracytoplasmic sperm injection (ICSI) and intrauterine insemination (IUI) are the most common techniques in this regard. Various microfluidic technologies can incorporate various ART procedures such as embryo and gamete (sperm and oocyte) analysis, sorting, manipulation, culture and monitoring. Hence, this review intends to summarize the current knowledge about the application of this approach towards cell biology to enhance ART.

Adipose-derived stem cells regulate metabolic homeostasis and delay aging by promoting mitophagy

Tissues undergo a process of degeneration as the body ages. Mesenchymal stem cells (MSCs) have been found to have major potential in delaying the aging process in tissues and organs. However, the mechanism underlying the anti-aging effects of MSC is not clear which limits clinical applications. In this study, we used adipose-derived mesenchymal stem cells (ADSCs) to perform anti-aging treatments on senescent cells and progeroid animal models. Following intervention with ADSCs, replicative senescence was delayed and metabolic homeostasis was transformed from catabolism to anabolism. Metabolomic tests were used to analyze different metabolites. We found that ADSCs acted to accelerate mitophagy which eliminated intracellular ROS and improved the quality of mitochondria. These processes acted to regulate the cellular metabolic homeostasis and ultimately delayed the process of aging. Allogeneic stem cell therapy in a Progeria animal model (DNA polymerase gamma (POLG) knockin, mitochondrial dysfunction) also showed that ADSC therapy can improve alopecia and kyphosis by promoting mitophagy. Our research confirms for the first time that allogeneic stem cell therapy can improve aging-related symbols and phenotypes through mitochondrial quality control. These results are highly significant for the future applications of stem cells in aging-related diseases.

A Brief Analysis of Tissue-Resident NK Cells in Pregnancy and Endometrial Diseases: The Importance of Pharmacologic Modulation

NK cells are lymphocytes involved in the innate and adaptative immune response. These cells are located in peripheral blood and tissues with ample functions, from immune vigilant to tolerogenic reactions. In the endometrium, NK cell populations vary depending on age, hormones, and inflammation. When pregnancy occurs, tissue-resident NK cells and conventional NK cells are recruited to protect the fetus, a tolerogenic response. On the contrary, in the inflamed endometrium, various inflammatory cells down-regulate NK tolerance and impair embryo implantation. Therefore, NK cells’ pharmacological modulation is difficult to achieve. Several strategies have been used, from progesterone, lipid emulsions to steroids; the success has not been as expected. However, new therapeutic approaches have been proposed to decrease the endometrial inflammatory burden and increase pregnancy success based on understanding NK cell physiology.

The promising biological role of postbiotics derived from probiotic Lactobacillus species in reproductive health

Recent investigations have meaningfully developed our knowledge of the features of the reproductive microbiome/metabolome profile and their relations with host responses to offer an optimal milieu for the development of the embryo during the peri-implantation period and throughout pregnancy. In this context, the establishment of homeostatic circumstances in the Female Reproductive Tract (FRT), in various physiological periods, is a significant challenge, which appears the application of postbiotics can facilitate the achievement of this goal. So, currently, scientific literature confirms that postbiotics due to their antimicrobial, antiviral, and immunomodulatory properties can be considered as a novel biotherapeutic approach. Future investigation in this field will shed more translational mechanistic understanding of the interaction of the postbiotics derived from vaginal Lactobacilli with females' health and reproduction.

Clinical effect of lymphocyte immunotherapy on patients with unexplained recurrent spontaneous abortion

Introduction

Lymphocyte immunotherapy (LIT) is believed to be a viable treatment for unexplained recurrent spontaneous abortion (URSA), but its effect remains controversial. This study aims to investigate the clinical effect of LIT in patients with URSA and clarify the factors that may influence the outcome of LIT.

Methods

This study included a total of 704 URSA patients, of which 444 patients accepted LIT treatment. URSA patients that did not accept LIT served as control group. Clinical characteristics were collected and analyzed between LIT and control group. The blocking antibody was tested before and after LIT. The outcome of LIT treatment was recorded. Logistic regression analysis was applied to evaluate the independent predictors of LIT success.

Results

After LIT treatment, 77.9% (346/444) of USRA patients turned to BA positive, and the conversion rate elevated with increased LIT (p < .001). LIT significantly improved the pregnancy rate and live birth rate in USRA patients (65.3% vs. 29.6%, p < .001; 80.3% vs. 50.6%, p < .001). Multivariate regression analysis suggested that younger maternal age and positive BA were independent predictors of LIT success.

Conclusion

LIT effectively induced the production of BA, and improved pregnancy rate and live birth rate in URSA patients. Our findings supported LIT as a beneficial treatment for URSA.

Does obesity based on body mass index affect semen quality?-A meta-analysis and systematic review from the general population rather than the infertile population

Whether obesity affects the quality of semen has become the focus of research. However, there are some deficiencies in the past research, because the vast majority of known infertile patients were included in the study samples. Taking infertile men as the research object to analyse the impact of obesity on semen quality, which cannot accurately prove that the impact on semen quality is caused by obesity, because the impact on semen quality may also be caused by other factors. Therefore, we selected ordinary obese men rather than infertile patients to conduct a systematic review and meta-analysis of the effects of obesity on semen parameters. The results showed that obesity had no effect on sperm concentration (SMD: -0.15, 95% CI: -0.32 ~ 0.02, p = .088) and percentage of normal sperm morphology (SMD: -0.17, 95% CI: -0.66 ~ 0.32, p = .487), but decreased semen volume (SMD: -0.32, 95% CI: -0.52 ~ -0.12, p = .002), total sperm number (SMD: -0.77, 95% CI: -1.31 ~ -0.23, p = .005), percentage of forward progression (SMD: -0.95, 95% CI: -1.7 ~ -0.19, p = .014) and percentage of viability (SMD: -0.812, 95% CI: -1.532 ~ -0.093, p = .027). Therefore, obesity affects semen quality to a certain extent, and maintaining normal weight may be one of the effective ways to improve male fertility.

Polystyrene microplastics lead to pyroptosis and apoptosis of ovarian granulosa cells via NLRP3/Caspase-1 signaling pathway in rats

Microplastics (MPs) considered as a new persistent environmental pollutant could enter into the circulatory system and result in decrease of sperm quantity and quality in mice. However, the effects of Polystyrene MPs (PS MPs) on the ovary and its mechanism in rats remained unclear. In this present study, thirty-two healthy female Wistar rats were exposed to different concentrations of 0.5 µm PS MPs dispersed in deionized water for 90 days. Using hematoxylin-eosin (HE) staining, the number of growing follicles was decreased compared to the control group. In addition, the activity of glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) were decreased while the expression level of malondialdehyde (MDA) was increased in ovary tissue. Confirmed by immunohistochemistry, the integrated optical density of NLRP3 and Cleaved-Caspase-1 had been elevated by 13.9 and 14 in granulosa cells in the 1.5 mg/kg/d group. Furthermore, compared to the control group, the level of AMH had been decreased by 23.3 pg/ml while IL-1β and IL-18 had been increased by 32 and 18.5 pg/ml in the 1.5 mg/kg/d group using the enzyme-linked immune sorbent assay (ELISA). Besides, the apoptosis of granulosa cells was elevated measured by terminal deoxyribonucleotide transferase-mediated nick end labeling (TUNEL) staining and flow cytometry. Moreover, western blot assays showed that the expressions of NLRP3/Caspase-1 signaling pathway related factors and Cleaved-Caspase-3 were increased. These results demonstrated that PS MPs could induce pyroptosis and apoptosis of ovarian granulosa cells via the NLRP3/Caspase-1 signaling pathway maybe triggered by oxidative stress. The present study suggested that exposure to microplastics had adverse effects on ovary and could be a potential risk factor for female infertility, which provided new insights into the toxicity of MPs on female reproduction.

Microfluidics as efficient technology for the isolation and characterization of stem cells

The recent years have been passed with significant progressions in the utilization of microfluidic technologies for cellular investigations. The aim of microfluidics is to mimic small-scale body environment with features like optical transparency. Microfluidics can screen and monitor different cell types during culture and study cell function in response to stimuli in a fully controlled environment. No matter how the microfluidic environment is similar to in vivo environment, it is not possible to fully investigate stem cells behavior in response to stimuli during cell proliferation and differentiation. Researchers have used stem cells in different fields from fundamental researches to clinical applications. Many cells in the body possess particular functions, but stem cells do not have a specific task and can turn into almost any type of cells. Stem cells are undifferentiated cells with the ability of changing into specific cells that can be essential for the body. Researchers and physicians are interested in stem cells to use them in testing the function of the body's systems and solving their complications. This review discusses the recent advances in utilizing microfluidic techniques for the analysis of stem cells, and mentions the advantages and disadvantages of using microfluidic technology for stem cell research.

The role of genital mycoplasma infection in female infertility: A systematic review and meta-analysis

PROBLEM

Recent studies show that lower genital tract infection with genital mycoplasma may be associated with the pathology of female infertility. However, this association remains controversial due to the variable prevalence, sample sizes, and different methods used to diagnose genital mycoplasma infection. The aim of the present meta-analysis was to gain better understanding of the specific impact of genital mycoplasma on female infertility.

METHOD OF STUDY

A systematic review of literature on the association of genital mycoplasma (Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum) infection and female infertility was performed using three electronic databases: PubMed, Scopus, and CINAHL, from January 2000 to January 2020. Pooled odds ratio (OR) and 95% confidence intervals for genital mycoplasma infection and female infertility were derived from a fixed effects model.

RESULTS

This meta-analysis included eight studies conducted in six countries. Based on the results, women with infertility had a statistically higher odds of having any genital mycoplasma infection (p < .0001) compared to the control group. The pooled OR of all the included studies was 3.82 (95% CI: 2.55, 5.72). There was an unremarkable heterogeneity in all the studies included in this meta-analysis (I²  = 0%, p = .48). A subgroup analysis also showed that M. genitalium, M. hominis, and U. urealyticum infections are significantly associated with female infertility.

CONCLUSION

Our meta-analysis showed a significant association between M. genitalium, M. hominis, and U. urealyticum infections and female infertility. This evidence supports the development of guidelines for the diagnosis and treatment of genital mycoplasma infections to prevent female infertility.

Endometriosis with infertility: A comprehensive review on the role of immune deregulation and immunomodulation therapy

BACKGROUND

Endometriosis is a multifactorial pathology dependent on intrinsic and extrinsic factors, but the immune deregulation seems to play a pivotal role. In endometriosis-associated infertility, this could raise the benefit of immunomodulatory strategies to improve the results of ART. In this review, we will describe (1) sera and peritoneal fluid cytokines and immune markers; (2) autoantibodies; and (3) immunomodulatory treatments in endometriosis with infertility.

METHODS

The literature research was conducted in MEDLINE, Embase, and Cochrane Library with the following keywords: "endometriosis", "unexplained miscarriage", "implantation failure", "recurrent implantation failure » and « IVF-ICSI », « biomarkers of autoimmunity", "TNF-α", "TNF-α antagonists", "infliximab", "adalimumab", "etanercept", "immunomodulatory treatment", "steroids", "intralipids", "intravenous immunoglobulins", "G-CSF", "pentoxyfylline".

RESULTS

Several studies analyzed the levels of pro-inflammatory cytokines in sera and peritoneal fluid of endometriosis-associated infertility, in particular TNF-α. Various autoantibodies have been found in peritoneal fluid and sera of infertile endometriosis women even in the absence of clinically defined autoimmune disease, as antinuclear, anti-SSA, and antiphospholipid autoantibodies. In few uncontrolled studies, steroids and TNF-α antagonists could increase the pregnancy rates in endometriosis-associated infertility, but well-designed trials are lacking.

CONCLUSION

Endometriosis is characterized by increased levels of cytokines and autoantibodies. This suggests the role of inflammation and immune cell deregulation in infertility associated with endometriosis. The strategies of immunomodulation to regulate these immune deregulations are poorly studied, and well-designed studies are necessary.

Advances of microfluidic technology in reproductive biology

According to World Health Organization (WHO) reports about 70 million couples suffer from infertility all over the world. A lot of research groups are working on this issue and have made therapeutic approaches by integrating biology, medicine, genetics, chemistry, psychology, mechanic, and many other branches of science. However, these methods have their own pros and cons. Assisted Reproductive Technologies (ART) has appeared to solve infertility problems. In Vitro Fertilization (IVF), Intracytoplasmic Sperm Injection (ICSI), Intrauterine Insemination (IUI) are the most common and conventional technologies in this regard. There are at least two characteristics of microfluidics, mechanical and biochemical, which can be influential in the field of mammalian gamete and preimplantation embryo biology. These microfluidic characteristics can assist in basic biological studies on sperm, oocyte and preimplantation embryo structure, function and environment. Using microfluidics in sorting sperm, conducting different steps of oocyte selection and preparation, and transferring embryo by passing sub-microliter fluid through microchannels results in low cost and short time. The size and shape of microchannels and the volume of used fluid differs from non-human cells to human cells. The most progressions have been seen in animal models. Results suggest that microfluidic systems will lead to improved efficiencies in assisted reproduction.