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Factors associated with aberrant imprint methylation and oligozoospermia
Norio Kobayashi1,2, Naoko Miyauchi1, Nozomi Tatsuta3
1Department of Informative Genetics, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
Scientific Reports
|February 11, 2017
Summary
Epigenetic alterations in sperm DNA methylation are linked to male infertility and impact pregnancy outcomes. Lifestyle factors and environmental exposures may cause these methylation errors, affecting assisted reproduction technology success.
Area of Science:
- Reproductive biology
- Epigenetics
- Environmental health
Background:
- Oligozoospermia (low sperm count) is rising in industrialized nations.
- Epigenetic alterations, particularly DNA methylation, are implicated in male infertility.
- Environmental and lifestyle factors can induce epigenetic changes affecting germ cells.
Purpose of the Study:
- To investigate DNA methylation levels at imprinted loci in sperm from infertile men.
- To identify associations between methylation errors, lifestyle factors, and sperm quality.
- To evaluate the impact of sperm methylation abnormalities on pregnancy outcomes and assisted reproduction technology (ART).
Main Methods:
- Analysis of DNA methylation at 22 human imprinted loci in 221 purified sperm samples.
- Structural equation modeling to explore causal relationships between factors.
- Correlation analysis of methylation status with lifestyle (smoking, diet), age, PCB exposure, and ART outcomes.
Main Results:
- Aberrant DNA methylation was found in 24.8% of infertile patients.
- Severe oligozoospermia was associated with aberrant methylation, smoking, and carbonated drink consumption.
- Aging indirectly influenced oligozoospermia via PCB accumulation.
- Sperm methylation errors correlated with decreased live-birth rates and increased miscarriage rates.
Conclusions:
- Environmental factors and specific lifestyle choices contribute to sperm methylation errors in infertile men.
- Abnormal sperm methylation negatively affects ART success and pregnancy outcomes.
- Normal sperm imprint methylation is crucial for safe and effective ART, potentially reducing congenital diseases.
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