scholarly journals Improving outcomes of after fertilization failure with intracytoplasmic sperm injection: the role of differentiating oocyte-related and sperm-related oocyte activation deficiency

2020 ◽  
Vol 114 (3) ◽  
pp. 497
Author(s):  
Kelli X. Gross ◽  
James M. Hotaling
Keyword(s):  
Intracytoplasmic Sperm Injection ◽  
Oocyte Activation ◽  
Fertilization Failure

Experiences with intracytoplasmic sperm injection

1995 ◽  
Vol 4 (2) ◽  
pp. 75-86 ◽  
Author(s):  
Susan E Lanzendorf
Keyword(s):  
Intracytoplasmic Sperm Injection ◽  
Meiotic Division ◽  
Reproductive Tract ◽  
Female Reproductive Tract ◽  
Oocyte Activation ◽  
Fertilization Failure ◽  
Cortical Granules ◽  
Specific Sequence ◽  
Mammalian Fertilization ◽  
Pass Through

Mammalian fertilization, whether it takes place within the female reproductive tract or within a laboratory dish, is comprised of many processes which must follow a specific sequence. The spermatozoon must bind to and pass through the zona pellucida, fuse with the oolemma and become incorporated into the cytoplasm of the oocyte. Fusion of the two gametes triggers oocyte activation, resulting in exocytosis of the cortical granules and completion of the second meiotic division of the oocyte. A block in one or more of these processes, due either to abnormalities in the spermatozoon or oocyte, may result in fertilization failure.

scholarly journals A novel homozygous mutation of phospholipase C zeta leading to defective human oocyte activation and fertilization failure

2020 ◽  
Vol 35 (4) ◽  
pp. 977-985 ◽  
Author(s):  
Peng Yuan ◽  
Cen Yang ◽  
Yixin Ren ◽  
Jie Yan ◽  
Yanli Nie ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Human Oocyte ◽  
Homozygous Mutation ◽  
Whole Genome ◽  
C2 Domain ◽  
Oocyte Activation ◽  
Fertilization Failure ◽  
Human Fertilization

Abstract STUDY QUESTION Is a novel homozygous phospholipase C zeta (PLCζ), c.1658 G>C; p. R553P mutation in the C2 domain associated with the outcomes of recurrent fertilization failure after ICSI? SUMMARY ANSWER PLCζ, c.1658 G>C led to defective human oocyte activation and fertilization failure, while this mutation in the C2 domain of PLCζ did not compromise concentration, motility and chromosome ploidy of sperm. WHAT IS KNOWN ALREADY Sperm-specific PLCζ is now widely considered to be the physiological stimulus that evokes intracellular calcium (Ca2+) oscillations, which are essential for egg activation during mammalian fertilization. Thus far, few genetic studies have shown that different point mutations in the PLCζ gene are associated with male infertility. STUDY DESIGN, SIZE, DURATION This was a basic medical research to assess pathogenicity for novel mutation in the C2 domain of PLCζ during human fertilization. PARTICIPANTS/MATERIALS, SETTING, METHODS Single-cell omics were applied to analyze the DNA methylation state of the fertilization failure oocytes and the ploidy of the patient’s sperm. Whole genome sequencing data for the patient were analyzed for mutations in PLCζ. Sanger sequencing confirmed the presence of a rare variant, and then the mutant and wild-type PLCζ mRNA were injected to observe oocyte activation. MAIN RESULTS AND THE ROLE OF CHANCE The fertilization failure oocytes (n = 4) were triploid and lacking proper DNA demethylation. The whole genome sequencing analysis revealed a novel missense homozygous mutation in PLCζ, c.1658 G>C; p. R553P, which leads to the conversion of arginine 553 to proline. This point mutation does not affect the production of the corresponding protein in sperm. However, microinjection of the mRNA transcribed from the PLCζ R553P mutation gene failed to trigger oocyte activation and the subsequent embryo development. LIMITATIONS, REASONS FOR CAUTION Only one patient with PLCζ mutations was available because of its rare incidence. WIDER IMPLICATIONS OF THE FINDINGS Notably, we discovered a novel homozygous mutation in PLCζ, which results in an abnormal conformation at the C2 domain of the PLCζ protein. Our findings indicate an essential role of PLCζ in human fertilization and the requirement of a normal structure of C2 domain in PLCζ-mediated physiological function. STUDY FUNDING/COMPETING INTEREST(S) This project is funded by the National Natural Science Foundation of China (31571544, 31871482, 31871447) and National Key Research and Development Program (2018YFC1004000, 2017YFA0103801). All authors declared no competing interests. TRIAL REGISTRATION NUMBER Not applicable.

scholarly journals Sperm-oocyte interplay: an overview of spermatozoon’s role in oocyte activation and current perspectives in diagnosis and fertility treatment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Ishraq Zafar ◽  
Shi Lu ◽  
Honggang Li
Keyword(s):  
Diagnostic Tests ◽  
Scientific Information ◽  
Male Gamete ◽  
Fertility Treatment ◽  
Normal Embryo ◽  
Oocyte Activation ◽  
Fertilization Failure ◽  
Sperm Selection ◽  
Reproductive Techniques

AbstractThe fertilizing spermatozoon is a highly specialized cell that selects from millions along the female tract until the oocyte. The paternal components influence the oocyte activation during fertilization and are fundamental for normal embryo development; however, the sperm-oocyte interplay is in a continuous debate. This review aims to analyze the available scientific information related to the role of the male gamete in the oocyte activation during fertilization, the process of the interaction of sperm factors with oocyte machinery, and the implications of any alterations in this interplay, as well as the advances and limitations of the reproductive techniques and diagnostic tests. At present, both PLCζ and PAWP are the main candidates as oocyte activated factors during fertilization. While PLCζ mechanism is via IP3, how PAWP activates the oocyte still no clear, and these findings are important to study and treat fertilization failure due to oocyte activation, especially when one of the causes is the deficiency of PLCζ in the sperm. However, no diagnostic test has been developed to establish the amount of PLCζ, the protocol to treat this type of pathologies is broad, including treatment with ionophores, sperm selection improvement, and microinjection with PLCζ protein or RNA.

Novel mutations in PLCZ1 cause male infertility due to fertilization failure or poor fertilization

2020 ◽  
Vol 35 (2) ◽  
pp. 472-481 ◽  
Author(s):  
Zheng Yan ◽  
Yong Fan ◽  
Fei Wang ◽  
Zhiguang Yan ◽  
Menghui Li ◽  
...  
Keyword(s):  
Male Infertility ◽  
Conflicts Of Interest ◽  
Missense Mutations ◽  
Oocyte Activation ◽  
Fertilization Failure ◽  
Novel Mutations ◽  
Primary Infertility ◽  
Human Fertilization ◽  
Poor Fertilization

Abstract STUDY QUESTION Do sperm-specific phospholipase C zeta (PLCZ1) mutations account for male infertility due to fertilization failure? SUMMARY ANSWER Six novel mutations and one reported mutation in PLCZ1 were identified in five of 14 independent families characterized by fertilization failure or poor fertilization, suggesting that these mutations may be responsible for fertilization failure in men exhibiting primary infertility. WHAT IS KNOWN ALREADY PLCZ1 is essential for the induction of intracellular calcium (Ca2+) oscillations and the initiation of oocyte activation during mammalian fertilization. However, genetic evidence linking PLCZ1 mutations with male infertility remains limited. STUDY DESIGN, SIZE, DURATION Fourteen unrelated primary infertility patients were recruited into this study from January 2016 to December 2018; the patients exhibited total fertilization failure or poor fertilization, as evidenced by ICSI and sperm-related oocyte activation deficiencies identified in mouse oocyte activation assays. PARTICIPANTS/MATERIALS, SETTING, METHODS Genomic DNA samples were extracted from the peripheral blood of patients. The whole exons of PLCZ1 were sequenced by Sanger sequencing. The PLCZ1 sequences were aligned by CodonCode software to identify rare variants. The ExAC database was used to search for the frequency of corresponding mutations. The pathogenicity of identified variants and their possible effects on the protein were assessed in silico. PLCZ1 protein levels in semen samples were evaluated by western blotting. Oocyte activation ability was assessed by the injection of wild-type and mutant PLCZ1 cRNAs into human mature metaphase II (MII) oocytes in vitro. MAIN RESULTS AND THE ROLE OF CHANCE We identified six novel mutations and one reported mutation in PLCZ1 among five affected individuals. In addition to four novel missense mutations, two new types of genetic variants were identified, including one in-frame deletion and one splicing mutation. Western blot analysis revealed that PLCZ1 protein expression was not observed in the semen samples from the five affected patients. Microinjection with the PLCZ1 cRNA variants was performed, and a significant decrease in the percentage of pronuclei was observed for four novel missense mutations and one novel in-frame deletion mutation, suggesting that these mutations have a deleterious influence on protein function. By artificial oocyte activation treatment, the fertilization failure phenotypes of four affected patients were successfully rescued and three healthy babies were delivered. LARGE SCALE DATA N/A LIMITATIONS, REASONS FOR CAUTION We screened only the whole exons of PLCZ1. Additional possible mutations in the non-coding region of PLCZ1 should be further studied. WIDER IMPLICATIONS OF THE FINDINGS Our study not only further confirms the important role of PLCZ1 in human fertilization but also expands the mutational spectrum of PLCZ1 associated with male infertility, which provides a basis for assessing genetic variation in PLCZ1 as a potential diagnostic marker for infertile men suffering from fertilization failure. STUDY FUNDING/COMPETING INTEREST(S) This research was supported by the National Natural Foundation of China (81 571 486 and 81 771 649). All authors have no conflicts of interest to declare.

Assessment of fertilization failure and abnormal fertilization after intracytoplasmic sperm injection (ICSI)

1995 ◽  
Vol 7 (2) ◽  
pp. 197 ◽  
Author(s):  
SP Flaherty ◽  
D Payne ◽  
NJ Swann ◽  
CD Matthews
Keyword(s):  
Intracytoplasmic Sperm Injection ◽  
Polar Body ◽  
Sperm Head ◽  
Oocyte Activation ◽  
Fertilization Failure ◽  
Metaphase Chromosomes ◽  
Polar Bodies ◽  
Abnormal Fertilization ◽  
Second Polar Body ◽  
Sperm Chromosomes

The assessment of fertilization is an important part of intracytoplasmic sperm injection (ICSI) and oocytes are routinely examined about 17 h after injection using Nomarski differential interference contrast optics. However, it is not possible to conclusively determine the aetiology of fertilization anomalies in this manner, so cytological studies were undertaken to determine the causes of failed and abnormal fertilization after ICSI. Oocytes which exhibited no evidence of fertilization, one pronucleus (PN) or 3 PN were fixed in glutaraldehyde, stained with Hoechst 33342 and examined by fluorescence microscopy to identify PN, metaphase chromosomes, sperm heads and polar bodies. A total of 428 unfertilized oocytes were examined from 170 ICSI cycles. Overall, 82% of these unfertilized oocytes were still at metaphase II (non-activated) while the remaining 18% were activated and had 1 PN and two polar bodies. The majority (71%) of the metaphase II oocytes contained a swollen sperm head, which indicates that the spermatozoon was correctly injected but the oocyte did not activate and complete its second meiotic division. The swollen sperm head was located among the metaphase chromosomes in 4.3% of these oocytes, while in some cases (6.6%), the sperm chromosomes had undergone premature chromosome condensation (PCC). Other aetiologies of failed fertilization in these metaphase oocytes were ejection of the spermatozoon from the oocyte (19%) and complete failure of sperm head decondensation (10%). A similar pattern of anomalies was found in 1 PN oocytes, although the ratios were different (swollen sperm head, 51%; ejection of the spermatozoon, 19%; undecondensed sperm head, 30%). Seventy abnormally fertilized oocytes were also examined, of which 63 had 3 PN and a single polar body, indicating that the unextruded second polar body developed into the third PN. In conclusion, the present study demonstrates that the principal cause of fertilization failure after ICSI is failure of oocyte activation and not ejection of the spermatozoon from the oocyte. It is also apparent that further studies are needed to elucidate the mechanisms that control oocyte activation and sperm head decondensation in injected oocytes.

scholarly journals A Novel Assisted Oocyte Activation Method Improves Fertilization in Patients With Recurrent Fertilization Failure

2021 ◽  
Vol 9 ◽  
Author(s):  
Meng Wang ◽  
Lixia Zhu ◽  
Chang Liu ◽  
Hui He ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Normal Distribution ◽  
Intracytoplasmic Sperm Injection ◽  
Fertilization Rate ◽  
The Novel ◽  
Oocyte Activation ◽  
Fertilization Failure ◽  
Activation Factor ◽  
Total Fertilization Failure ◽  
Signaling Activation ◽  
Assisted Oocyte Activation

Total fertilization failure (TFF) occurs in 1–3% of total intracytoplasmic sperm injection (ICSI) cycles and can reoccur in subsequent cycles. Despite the high success rate with the application of assisted oocyte activation (AOA), there is still a small number of couples who cannot obtain fertilized eggs after conventional calcium (Ca2+) ionophores-based ICSI-AOA. Six couples experiencing repeated TFF or low fertilization (<10%) after ICSI and conventional ICSI-AOA were enrolled in this study. Compared with the regular ICSI group and the conventional ICSI-AOA group, the new AOA method, a combination of cycloheximide (CHX) and ionomycin, can significantly increase the fertilization rate from less than 10 up to approximately 50% in most cases. The normal distribution of sperm-related oocyte activation factor phospholipase C zeta (PLCζ1) in the sperms of the cases indicated the absence of an aberrant Ca2+ signaling activation. The results of the whole-embryo aneuploidies analysis indicated that oocytes receiving the novel AOA treatment had the potential to develop into blastocysts with normal karyotypes. Our data demonstrated that CHX combined with ionomycin was able to effectively improve the fertilization rate in the majority of patients suffering from TFF. This novel AOA method had a potential therapeutic effect on those couples experiencing TFF, even after conventional AOA, which may surmount the severe fertilization deficiencies in patients with a repeated low fertilization or TFF.

scholarly journals Progesterone treatment of boar spermatozoa improves male pronuclear formation after intracytoplasmic sperm injection into porcine oocytes

Zygote ◽  
2002 ◽  
Vol 10 (2) ◽  
pp. 95-104 ◽  
Author(s):  
Mike Katayama ◽  
Takashi Miyano ◽  
Masashi Miyake ◽  
Seishiro Kato
Keyword(s):  
Plasma Membrane ◽  
Intracytoplasmic Sperm Injection ◽  
Acrosome Reaction ◽  
Sperm Chromatin ◽  
Oocyte Activation ◽  
Freezing And Thawing ◽  
Chromatin Decondensation ◽  
Progesterone Treatment ◽  
Pronuclear Formation ◽  
Boar Spermatozoa

Boar spermatozoa were prepared for intracytoplasmic sperm injection (ICSI) by two different treatments to facilitate sperm chromatin decondensation and improve fertilisation rates after ICSI in pigs: spermatozoa were either frozen and thawed without cryoprotectants, or treated with progesterone. Morphological changes of the sperm heads after the treatments were examined and then the activation of oocytes and the transformation of the sperm nucleus following ICSI were assessed. After freezing and thawing, the plasma membrane and acrosomal contents over the apical region of sperm head were lost in all the spermatozoa. Following treatment with 1 mg/ml progesterone, the acrosome reaction was induced in 61% of spermatozoa. After injection of three types of spermatozoa, non-treated spermatozoa and progesterone-treated (i.e. acrosome-reacted) spermatozoa induced oocyte activation, but frozen-thawed spermatozoa induced oocyte activation at a significantly lower rate. Sixty-two per cent of sperm heads remained orcein-negative for 6 h, however, resulting in delayed sperm chromatin decondensation and low male pronuclear formation in the oocytes injected with a non-treated spermatazoon. Since the treatments of freezing and thawing and progesterone for spermatozoa accelerated the initial change in sperm chromatin and the latter treatment induced oocyte activation earlier, it is considered that the delay in oocyte activation and decondensation of sperm chromatin after injection of non-treated spermatozoa is caused by the existence of the sperm plasma membrane. These results show that progesterone treatment efficiently induces the acrosome reaction in boar spermatozoa without destroying their potency for oocyte activation, and the induction of the acrosome reaction results in the promotion of male pronuclear formation after ICSI.

Sign in / Sign up

Export Citation Format

Share Document