Creatine enhances the duration of sperm capacitation: a novel factor for improving in vitro fertilization with small numbers of sperm
Umehara T, Kawai T, Goto M, Richards JS, Shimada M
Human reproduction (Oxford, England) · 48 citations
How it was studied
- Design
- Animal study (classified by our AI screen)
- Studied in
- Animals
- Main outcome
- Health markers and function
Who paid for it
- Funding
- Independent funding
- Government
- Japan Agency for Medical Research and Development
- Government
- National Institutes of Health
- Government
- Japan Society for the Promotion of Science
- Government
- Eunice Kennedy Shriver National Institute of Child Health and Human Development
- Government
- NICHD NIH HHS
- Government
- JSPS KAKENHI
- Grants
- Japan Society for the Promotion of Science (24688028); Japan Agency for Medical Research and Development (16gk0110015h0001); Eunice Kennedy Shriver National Institute of Child Health and Human Development (R01-HD076980); Japan Society for the Promotion of Science (17K19324); Japan Society for the Promotion of Science (15J05331); Japan Society for the Promotion of Science (16H05017); National Institutes of Health (NIH-HD-076980)
Based on 6 listed funder(s).
Publication
- Published
- 2018-03-16 · Hum Reprod · vol. 33 · issue 6 · pp. 1117–1129
- Publisher
- Oxford University Press
- Cited
- 67 citations · more than 95% of similar papers · 4.9× the field average
- Impact
- Top 10% most cited in its field
- References
- 51 works
- Access
- Free to read
- Research areas
- Sperm and Testicular Function · Muscle metabolism and nutrition · Reproductive Biology and Fertility
- Keywords
- Capacitation, Sperm, Human fertilization, Andrology, Ovulation, Oocyte, In vitro fertilisation, Creatine, Biology, Sperm motility, In vivo, Endocrinology, Internal medicine, Medicine, Embryo, Anatomy, Hormone, Cell biology, Genetics
- MeSH
- animals, mice, inbred c57bl, humans, disease models, animal, guanidines, creatine, blotting, western, fertilization in vitro, sperm motility, sperm capacitation, female, male, cumulus cells, in vitro oocyte maturation techniques
5 authors
From JP, US
- Takashi UmeharaHiroshima University
- Tomoko KawaiHiroshima University
- Masaaki GotoToyama Prefectural Agricultural, Forestry & Fisheries Research Center; Oita Prefectural Agriculture, Forestry and Fisheries Research Center
- JoAnne S. RichardsBaylor College of Medicine
- Masayuki Shimada · correspondingHiroshima University
Abstract
Study question
Why are many sperm required for successful fertilization of oocytes in vitro, even though fertilization occurs in vivo when only a few sperm reach the oocyte?
Summary answer
Creatine produced in the ovary promotes efficient fertilization in vivo; however, in vitro, creatine is not contained in the in vitro fertilization (IVF) medium.
What is known already
The IVF medium enables capacitation of sperm. However, the IVF medium does not fully mimic the in vivo environment during fertilization. Consequently, fertilization in vitro is more inefficient than in the oviduct.
Study design, size, duration
Follicular and oviductal fluids were collected and then analyzed for creatine and glucose levels. To determine the physiological functions of creatine, the creatine antagonist 3-guanidinopropionic acid (GPA) was injected into hormonally primed mice. Using conventional IVF protocols, sperm were pre-incubated in IVF medium with creatine and then co-cultured with 10 ovulated cumulus-oocyte complexes (1-1000 per oocyte) in 50 μl medium droplets.
Participants/materials, setting, methods
Glucose and creatine levels were measured using commercial enzymatic assay kits. The effect of creatine in vivo was assessed by mating experiments using mice treated with or without GPA just before ovulation. To assess the functions of sperm incubated in IVF medium containing creatine, we analyzed (1) the motility of sperm using computer-assisted sperm assay, (2) the capacitation level of sperm by western blot analyses, and (3) the condition of sperm acrosomes by peanut agglutinin lectin-FITC staining.
Main results and the role of chance
Oviductal creatine levels were significantly increased following ovulation. Injecting mice with GPA just before ovulation significantly reduced the number of fertilized oocytes. The addition of creatine to IVF medium enhanced sperm capacitation by increasing ATP levels. Successful fertilization was achieved with as few as five sperm/oocyte in the creatine group, and the number of fertilized oocytes was significantly higher than in the control without creatine (P < 0.01).
Limitations, reasons for caution
In the present study, a pharmacological approach, creatine antagonist (GPA) treatment, but not a knockout mouse model, was used to understand the role of creatine in vivo. The role of creatine in fertilization processes can only be shown in a mouse model.
Wider implications of the findings
A modified IVF technique using creatine-containing medium was developed and shown to markedly improve fertilization with small numbers of sperm. This approach has the potential to be highly beneficial for human assisted reproductive technologies, especially for patients with a limited number of good quality sperm.
Study funding/competing interest(s)
This work was supported in part by JSPS KAKENHI Grant numbers JP24688028, JP16H05017 (to M.S.), and JP15J05331 (to T.U.), the Japan Agency for Medical Research and Development (AMED) (16gk0110015h0001 to M.S.), and National Institutes of Health (NIH-HD-076980 to J.S.R). The authors have nothing to disclose.
Abstract via Europe PMC. Copyright remains with the authors or publisher.
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