Stem cells and organs-on-chips: new promising technologies for human infertility treatment

Having biological children remains an unattainable dream for most couples with reproductive failure or gonadal dysgenesis. The combination of stem cells with gene editing technology and organ-on-a-chip models provides unique opportunity for infertile patients with impaired gametogenesis caused by congenital disorders in sex development or cancer survivors. But, how will these technologies overcome human infertility? This review discusses the regenerative mechanisms, applications and advantages of different types of stem cells for restoring gametogenesis in infertile patients, as well as major challenges that must be overcome prior to clinical application. The importance and limitations of in vitro generation of gametes from patient-specific human induced pluripotent stem cells (hiPSCs) will be discussed in the context of human reproduction. The potential role of organ-on-a-chip models that can direct differentiation of hiPSCs-derived primordial germ cell-like cells to gametes and other reproductive organoids is also explored. These rapidly evolving technologies provide future prospects for improving fertility to individuals and couples who experience reproductive failure.

Reproductive Failure and Thrombophilia: Not Enough Evidence for a Tight Bond

<b><i>Objectives:</i></b> The role of hereditary thrombophilia in reproductive failure (RF) is strongly debatable. In this retrospective single-center study, we analyzed pregnancy outcome in 175 women screened for thrombophilia after at least one event of RF. <b><i>Results:</i></b> The prevalence of thrombophilia in our cohort was 33.4%. Pregnancy survival curves were not different according to severity (log-rank, <i>p</i> = 0.302) or type of thrombophilia (log-rank, <i>p</i> = 0.532). In total, 81.7% of 175 subsequent pregnancies were proceeded with LMWH. Concomitant use of ASA was prescribed in 75 pregnancies according to physician choice. The primary endpoint was live birth rate (LBR) that succeeded in 152/175 next pregnancies (86.8%) and late obstetric complications (LOBC) which occurred in 17/175 next pregnancies (9.8%). In logistic regression analysis, neither the severity nor the type of thrombophilia was important for any pregnancy outcome (LBR or LOBC). Considering therapeutic interventions, the use of LMWH ± ASA was not related to LBR or LOBC. The only factor inversely related to LBR was age above the cutoff value of 35.5 years (<i>p</i> = 0.049). <b><i>Conclusions:</i></b> Incidence of thrombophilia is increased among women with RF, but the severity or type of thrombophilia is not related to pregnancy outcome.

A Systematic Investigation Unveils High Coinfection Status of Porcine Parvovirus Types 1 through 7 in China from 2016 to 2020

Porcine parvoviruses (PPVs) are prevalent in China associating with reproductive failure in swine. The coinfection of seven genotypes of PPVs (PPV1-7) might have synergistic effects on PPV1 associated SMEDI syndrome.

265 Awardee Talk: Maternal and Paternal Contributions to Fertility

Using over 56,000 pregnancy diagnostic records in beef cattle, a meta-analysis was conducted to objectively determine that 28.4 % of embryos will not develop past day 7 of gestation with most embryonic losses occurring before day 4. Furthermore, by day 30 of gestation, 47.9 % of cows submitted to a single insemination at day 0 will not be pregnant and pregnancy loss between days 32 and 100 was 5.8%. Reproductive success, however, is highly variable and influenced by maternal and paternal factors. Maternal characteristics, including subspecies, parity and reproductive tract size, intersect with breeding management decisions regarding estrus expression and detection to influence conception and pregnancy rates. The maternal endocrine environment, from estradiol associated with estrus around fertilization to elevated prostaglandins during the embryonic to fetal transition period, play critical roles in pregnancy success. Despite the numerous maternal factors involved with pregnancy establishment, sire contribution to reproductive failure should not be overlooked. Sires are reported to influence pregnancy loss during the second month of gestation in both beef and dairy herds. These differences in sire field fertility could not be explained by differences in semen characteristics nor differences in sire conception rate (SCR) score. To understand parental contribution to pregnancy development during the second month of gestation we developed parthenogenetic (PA) embryos (embryos lacking paternal genome). We observed that PA conceptus had well developed trophectoderm tissue at day 31 of gestation but no site of embryo attachment to the endometrium. Moreover, conceptus secretion such as pregnancy-associated glycoproteins and interferon-stimulated genes were not found in maternal circulation. These results suggest that paternal genetics is required for post-elongated embryo attachment to endometrium. Further exploring the maternal vs paternal contribution to pregnancy development can help elucidate the mechanism that drives reproductive failure in cattle.

First detection and phylogenetic analysis of porcine circovirus 3 in female donkeys with reproductive disorders

Background PCV3 is a pathogen associated with porcine dermatitis and nephropathy syndrome (PDNS)-like clinical signs, reproductive failure, and cardiac and multiorgan inflammation, which was newly identified in 2016 in sows in USA. Recently, PCV3 has also been identified from several non-porcine species like (cattle, dog, wild boar, deer, mice and ticks). However, PCV3 infection in donkey is not well established. Since 2019, 300 blood samples were collected from female donkey, which was characterized by abortion and sterility, in Liaocheng city of China. Results In the present study, an investigation of PCV3 in donkey blood samples was undertaken employing by real time PCR. Positive rates of PCV3 in donkeys reach to 21.0 %. In addition, one full-length PCV3 genome sequence was obtained, and it had a highest identity with porcine circovirus 3 PCV3/CN/Nanjing2017 strain and is clustered to PCV3a genotype based on ORF2 sequences. Conclusions This is the first report of detection of PCV3 from female donkeys presenting reproductive failure in large-scale donkey farms, China. In addition, the PCV3 strain identified in this study shared the closest relationship with those from porcine, suggesting that PCV3 may be transmitted from pigs to donkeys. Totally, PCV3 infection in donkey should be concerned although the association between it and reproductive failure are not better understood.

Molecular detection of Toxoplasma gondii in aborted fetuses of goats in Chattogram, Bangladesh

Background and Aim: Toxoplasma gondii is a protozoan parasite that is responsible for the major cause of congenital diseases, abortion, and stillbirth in humans and farm animals. Primary infection in pregnant goats due to T. gondii leads to abortion and significant economic losses in the livestock industry. Moreover, very few studies have been performed for the identification of T. gondii from aborted fetuses of goats. The study was conducted for the molecular identification of Toxoplasma gondii from aborted fetuses of goats in Chattogram, Bangladesh. Materials and Methods: Twenty aborted fetuses of goats were collected from 52 farms in the study area. A nested polymerase chain reaction (PCR) assay targeting the B1 gene was performed, and a positive sample yield of 197 bp amplified DNA products consistent with T. gondii. Results: The overall prevalence of toxoplasmosis in the aborted fetus of goats was 35.0%. Heart muscle, liver, brain, and placenta showed positive PCR results. The risk factors related to the does age, presence of cats in farms, and aborted fetus age were found to be statistically significant (p<0.05). Our results showed that T. gondii is a major possible causal factor for abortion and reproductive failure in goats. The high prevalence of T. gondii infection in aborted fetuses of goats revealed that T. gondii could be imperative in causing reproductive failure in goats. Conclusion: Active or congenital toxoplasmosis was shown by the presence of T. gondii in fetal tissues, which is a matter of concern as this parasite has zoonotic significance and causes economic hazards to the livestock industry by causing various reproductive problems. Therefore, proper control measures and strategies are needed to reduce the rate of abortion in goats, ultimately saving the livestock industry.

A History of Endometriosis Is Associated With Decreased Peripheral NK Cytotoxicity and Increased Infiltration of Uterine CD68+ Macrophages

Women with endometriosis may have a defective immune system. However, evidence of the immune responses of endometriosis patients with a history of endometriosis surgery is lacking, and the association between the location of endometriosis lesions and immune responses is unclear. This retrospective study included 117 females with reproductive failure and a history of endometriosis and 200 females with reproductive failure but without endometriosis to analyze their endometrial and peripheral immune responses. The results show that endometriosis was associated with decreased peripheral natural killer (NK) cytotoxicity and increased uterine macrophages. Peripheral NK cytotoxicity at effector-to-target ratios of 25:1 and 50:1 was significantly reduced in women with a history of endometriosis from that of the control group (26.6% versus 33.3% and 36.1% versus 43.3%, respectively, both P &lt; 0.001). Furthermore, after further division of patients into three subgroups according to the location of endometriosis lesions, we observed that NK cytotoxicity in the endometriosis subgroups, especially the mixed endometriosis group, was strongly decreased from that of the controls (P = 0.001). The endometrial CD68+ macrophage proportion in the mixed endometriosis subgroup was higher than that in the control group (2.8% versus 2.1%, P = 0.043). In addition, the baseline estradiol (E2) level was weakly correlated with the percentage of endometrial macrophages (r = 0.251, P = 0.009), indicating a potential association among the endocrine system, endometrial immune environment, and endometriosis. This study indicated that peripheral NK cytotoxicity and endometrial immune cell profiles could be useful for diagnosing and treating endometriosis and endometriosis-related reproductive diseases.

High Co-infection Status of Novel Porcine Parvovirus 7 With Porcine Circovirus 3 in Sows That Experienced Reproductive Failure

Porcine parvoviruses (PPVs) and porcine circoviruses (PCVs) infect pigs worldwide, with PPV1–7 and PCV2 infections common in pigs. Although PPV7 was only identified in 2016, co-infection of PPV7 and PCV2 is already common, and PPV7 may stimulate PCV2 replication. PCV3, a novel type of circovirus, is prevalent in pig populations worldwide and considered to cause reproductive disorders and dermatitis nephrotic syndrome. In recent studies, pigs were commonly infected with both PCV3 and PPV7. Our objective was to investigate the co-infections between PPV7 and PCV3 in samples from swine on farms in Hunan, China, and assess the potential impacts of PPV7 on PCV3 viremia. A total of 209 samples, known to be positive (105) or negative (104) for PCV3, were randomly selected from serum samples that were collected from commercial swine herds in seven regions from 2016 to 2018 in our previous studies; these samples were subjected to real-time PCR to detect PPV7. Of these samples, 23% (48/209) were positive for PPV7. Furthermore, the PPV7 positive rate was significantly higher in PCV3 positive serum (31.4%, 33/105) than in PCV3 negative serum (14.4%, 15/104). Another 62 PCV3 positive sow serum samples and 20 PCV3 positive aborted fetuses were selected from 2015 to 2016 in our other previous study. These samples were designated as being from farms with or without long-standing histories of reproductive failure (RF or non-RF), respectively, and they were also subjected to real-time PCR to detect PPV7 and to determine whether PPV7 affected PCV3 viremia. Among the 62 serum samples (39 PCV3 positive RF-serum and 23 PCV3 positive non-RF-serum), 45.1% (28/62) were positive for PPV7 and PCV3, and the PPV7 positive rate was significantly higher in PCV3 positive RF-serum (51.2%, 20/39) than in PCV3 positive non-RF-serum (34.8%, 8/23). In addition, there was a higher positive rate of PPV7 (55%, 11/20) in PCV3 positive aborted fetus samples. In addition, the copy number of PCV3 in PPV7 positive samples was significantly higher than that in PPV7 negative serum samples. Based on these findings, we concluded that PPV7 may stimulate PCV3 replication.

Bovine endometrial cells do not mount an inflammatory response to Leptospira

Leptospirosis causes abortion, premature birth, and stillbirth in cattle, but the mechanisms remain unclear. Infected cattle shed Leptospira intermittently and present a range of clinical symptoms, making diagnosis difficult. The primary route of Leptospira transmission in any animal is colonization of the renal tubule and excretion by urine, however Leptospira can also colonize the female reproductive tract of cows and can be transmitted by semen. Vaccination against Leptospira in the United States is routine in cattle, but immunity is not guaranteed. The cell wall of Leptospira contains Toll-like receptor agonists including peptidoglycan and lipopolysaccharide. The capacity of Leptospira to initiate an innate inflammatory response from uterine endometrial cells is unknown but may be a cause of reproductive failure. Using cell culture, we tested the capacity of bovine endometrial epithelial cells or human monocytes to elicit an inflammatory response to Leptospira borgpetersenii serovar Hardjo strain TC273. Cells were exposed to either heat-killed Leptospira, Leptospira outer membrane, Escherichia coli lipopolysaccharide, Pam3CSK4 or medium alone for 2 to 24 hours. Exposure of bovine endometrial epithelial cells or human monocytes to heat-killed Leptospira or Leptospira outer membrane did not induce the expression of IL1A, IL1B, IL6 or CXCL8, while exposure to E. coli lipopolysaccharide or Pam3CSK4 increased expression of IL1A, IL1B, IL6 and CXCL8 compared to control cells. This data suggests that Leptospira does not trigger a classical inflammatory response in endometrial cells. Understanding the interaction between Leptospira and the female reproductive tract is important in determining the mechanisms of Leptospirosis associated reproductive failure.