SARS-CoV-2 infection negatively impacts on the quality of embryos by delaying early embryonic development.

BACKGROUND: The COVID-19 pandemic is an unprecedented health crisis that has affected in vitro fertilization practices globally. Previous studies have shown that SARS-CoV-2 impacts the quality of embryos by inducing an immunological response in infertile patients. In this study, the early embryonic development of SARS-CoV-2-infected infertile patients was investigated. METHODS: Sixty-five SARS-CoV-2 infected infertile patients and 258 controls were involved in this study. The major outcome parameters for the cycle were analyzed, including the number of oocytes, maturation oocytes, available embryos per cycle, and embryo morpho kinetic characteristics. RESULTS: From SARS-CoV-2 infection until oocyte retrieval, it took an average of 6.63 days. The results revealed that the number of oocytes and high-quality embryos on day 3 dramatically reduced in SARS-CoV-2-infected infertile patients. SARS-CoV-2 was detected in the follicular fluid of three infertile patients. SARS-CoV-2 infection had negatively impacted the number of oocytes in multivariate linear regression models. The early embryonic development in the SARS-CoV-2 infection group had a noticeable delay from the six-cell stage to blastocyst stage. CONCLUSIONS: SARS-CoV-2 infection reduced the number of oocytes and high-quality embryos on day 3. It delays the early embryonic development from the six-cell stage to blastocyst stage and has a negative impact on the quality of embryos.

The efficacy of sequential day 3 embryo and blastocyst transfer in patients with repeated implantation failure.

OBJECTIVE: To evaluate the efficacy of sequential transfer that one cleavage-stage embryo on day 3 and one blastocyst on day 5 are sequentially transferred in the same treatment cycle over conventional day 3 embryo transfer and blastocyst transfer in patients with repeated implantation failure (RIF). STUDY DESIGN: 2836 frozen embryo transfer (FET) cycles in patients with RIF were divided into three groups according to female age: <35, 35-39 and >39 years old groups, and four groups depending on the number and period of embryo transferred: two day 3 embryo, two blastocyst, single blastocyst and sequential transfer groups; Pregnancy outcomes including implantation rate (IR), clinical pregnancy rate (CPR), abortion rate (AR), ectopic pregnancy rate (EPR), multiple pregnancy rate (MPR), live birth rate (LBR) and neonatal characteristics from all the groups were assessed. RESULTS: Sequential transfer caused a significant increase in the IR, CPR and LBR over two day 3 embryo transfer and did not improve the IR, CPR and LBR over two blastocyst transfer in patients with RIF. Sequential transfer had higher CPR, MPR and LBR and lower IR than single blastocyst transfer. No significant differences were present in neonatal characteristics among the transfer protocol groups. Singleton group had a higher average gestational age and birthweight as well as a lower cesarean section rate, preterm labor rate and low birthweight rate than twin group. Additionally, the AR had no significant difference and the EPR of blastocyst transfer was low. CONCLUSIONS: Sequential transfer was not an effective method to improve IR in patients with RIF, and blastocyst transfer with higher IR was suggested. Single blastocyst transfer could serve as an effective transfer protocol to reduce MPR.

The Effects of Different Post-thawed Culture Periods on Clinical Outcomes in Frozen Embryo Transfer Cycle.

The purpose of this study is to evaluate the effects of different post-thawed culture periods on the clinical outcomes. 9381 frozen embryo transfer (FET) cycles were divided into three groups according to female age: < 35, 35-39, and > 39 years, and two groups depending on post-thawed culture period before transfer: short culture (2-3 h) group (S) and long culture (18-20 h) group (L). According to the increment number of post-thawed embryos, the L group divided into three groups: ≤ 2, one ≤ 2 and the other > 2, and > 2 groups. Pregnancy outcomes included the implantation rate (IR), clinical pregnancy rate (CPR), multiple pregnancy rate (MPR), live birth rate (LBR), and neonatal characteristics. Long post-thawed culture caused a significant increase in the IR, CPR, MPR, and LBR (p = 0.000, 0.004, 0.037, and 0.001; CI = 1.06-1.194, 1.042-1.237, 1.008-1.254, and 1.054-1.245, respectively), and blastomere increment number also had a significant effect on IR, CPR, MPR, and LBR (p = 0.000, 0.000, 0.000, and 0.000, respectively). No significant differences were present in neonatal characteristics between the two post-thawed culture groups. Singleton group had a higher average gestational age and birthweight as well as a lower cesarean section rate, preterm labor rate, and low birthweight rate than twins group. Long post-thawed culture was associated with higher IR, CPR, MPR, and LBR, and transferring a well-developed embryo after long post-thawed culture might be a viable embryo transfer strategy to decrease MPR while maintaining CPR and LBR.

Successful birth after ICSI with testicular immotile spermatozoa from a patient with total MMAF in the ejaculates: a case report.

There has been no report on the outcome of vitrified blastocyst transfer from a vitrified oocyte injected with immotile testicular spermatozoa with only multiple morphological abnormalities of the sperm flagella (MMAF). A couple diagnosed with MMAF returned to the clinic to attempt pregnancy using their vitrified oocytes. Testicular spermatozoa were injected intracytoplasmically, and the following intracytoplasmic sperm injection results were observed. In the second cycle, surplus vitrified oocytes and testicular retrieved sperm were used, but no pregnancy ensued. In the third cycle, a surplus vitrified blastocyst was transferred, and a healthy female child was delivered, with a birth weight of 3050 g and a birth length of 53 cm. In this report we describe a successful pregnancy achieved in a patient presenting MMAF. The successful pregnancy was obtained from vitrified oocytes microinjected with testicular retrieved sperm in a vitrified blastocyst transfer.

Transcriptomic Variation during Spermiogenesis in Mouse Germ Cells.

To explore variations in the transcription activity during spermiogenesis, round and elongated spermatids were collected from ICR/CD1 model mice using laser capture microdissection (LCM) and cauda epididymal sperm samples. The transcripts were sequenced using RNA-seq, and the reads were mapped to mm9. The majority of the reads (70%) in the round and elongated spermatids were mappable to known and predicted exons, but that in sperm was only 9%. The results of the distribution of reads suggested that alternative splicing was more complicated in sperm than in round and elongated spermatids. In the 19,127 genes, we detected the expression of 5,104 de novo genes and 91,112 alternative splicing events, and 12,105 were differentially expressed. Gene ontology (GO), InterPro domains, and KEGG revealed changes in gene transcription, mitochondrial protein translation, cellular components, and energy metabolism during spermiogenesis. The results provided considerable information about alternative splicing events, differentiallly expressed genes (DEGs), and novel transcriptions during spermiogenesis in mice.

[Advance on research of gene expression during spermiogenesis at transcription level].

After meiosis, round spermatid develops into mature sperm through metamorphosis. During this stage, most cytoplasm in the germ cell is gradually lost. The histones associated with chromatin are replaced by transition proteins and eventually transformed into protamines. Thus, the spermatid chromatin is stringently packaged and highly concentrated. It was thought that the transcription activity of spermatid is lost and RNAs are absent in spermatid. Nevertheless, many types of transcripts are detected in recent years, including the transcripts needed during chromatin repackaged and some small RNAs, etc. Because histones in the nuclear are not replaced entirely, and there are some active sites on the chromatin, we conjectured that spermatid has some transcription activity, and this activity is regulated by hormone and epigenetic modification. These RNAs may be the residues in the spermatogenesis, or timely expressed during spermiogenesis. A deep study on gene transcription in spermiogenesis will help understand the genetic characteristics and provide the theoretic basis for reproductive control using male gamete. This article reviewed recent advances in spermiogenesis at gene transcription level and proposed the future research directions.