High-altitude hypoxia may negatively impact male reproductive functions inducing oxidative stress in spermatozoa. Oxidative dysregulation is associated with reduced seminal quality, genome integrity and mitochondrial dysfunction. However, the mechanistic bases are not completely known. Accordingly, our aim was to investigate the effects of high-altitude exposure on sperm telomere length (STL), an indicator of sperm quality and fertility potential, and on the methylation profile of BCL2 and BMP2, which are implicated in redox defences and mitochondrial homeostasis. The study included 9 Italian Caucasian males participants of the expedition "Lobuche PeakPyramid Exploration & Physiology" in Nepal from October 19 to November 9, 2022. Semen collection was performed according to the World Health Organization (WHO) indications at four times: at baseline before the expedition (BL), once back following altitude exposure (END), three weeks later (3WK) and three months later (3MO). Telomere length evaluation was performed by Quantitative Real-Time PCR employing the Absolute Human Telomere Length and Mitochondrial DNA Copy Number Dual Quantification qPCR Assay Kit (ScienceCell) comparing samples collected at BL and at 3MO. Samples were processed by a QuantStudioTM 7 Pro Real-Time PCR detection system (Life Technologies) and statistically analysed using the 2 – ΔΔCt method. Methylation analysis of 4 CpG sites for BCL2 and 8 CpG sites for BMP2 promoter was conducted following DNA bisulfite-conversion by the EpiTect Plus DNA Bisulfite Kit (Qiagen) and PCR amplification using the PyroMark PCR kit (Qiagen). Samples were then processed by a PyroMark Q96 ID system (Qiagen) and raw data were interpreted by the PyroMark CpG software (Qiagen). Regarding STL assessment, our results reported a statistically significant reduction in telomere length in five participants (p=0.048) suggesting a delayed genomic effect following hypoxic conditions. Conversely, no statistically significant changes in methylation levels of BCL2 (p=0.438) and BMP2 (p=0.154) were reported between BL and 3MO samples. Overall, these results may provide further insights into the molecular mechanisms affected by hypoxic environmental conditions and their potential implications for male infertility.
Effects of high-altitude exposure on telomere length and DNA methylation profiles in human spermatozoa
Rosa Maria Fratini;Fani Konstantinidou;Marisa Donato;Arcangelo Barbonetti;Antonio Capalbo;Liborio Stuppia;
2026-01-01
Abstract
High-altitude hypoxia may negatively impact male reproductive functions inducing oxidative stress in spermatozoa. Oxidative dysregulation is associated with reduced seminal quality, genome integrity and mitochondrial dysfunction. However, the mechanistic bases are not completely known. Accordingly, our aim was to investigate the effects of high-altitude exposure on sperm telomere length (STL), an indicator of sperm quality and fertility potential, and on the methylation profile of BCL2 and BMP2, which are implicated in redox defences and mitochondrial homeostasis. The study included 9 Italian Caucasian males participants of the expedition "Lobuche PeakPyramid Exploration & Physiology" in Nepal from October 19 to November 9, 2022. Semen collection was performed according to the World Health Organization (WHO) indications at four times: at baseline before the expedition (BL), once back following altitude exposure (END), three weeks later (3WK) and three months later (3MO). Telomere length evaluation was performed by Quantitative Real-Time PCR employing the Absolute Human Telomere Length and Mitochondrial DNA Copy Number Dual Quantification qPCR Assay Kit (ScienceCell) comparing samples collected at BL and at 3MO. Samples were processed by a QuantStudioTM 7 Pro Real-Time PCR detection system (Life Technologies) and statistically analysed using the 2 – ΔΔCt method. Methylation analysis of 4 CpG sites for BCL2 and 8 CpG sites for BMP2 promoter was conducted following DNA bisulfite-conversion by the EpiTect Plus DNA Bisulfite Kit (Qiagen) and PCR amplification using the PyroMark PCR kit (Qiagen). Samples were then processed by a PyroMark Q96 ID system (Qiagen) and raw data were interpreted by the PyroMark CpG software (Qiagen). Regarding STL assessment, our results reported a statistically significant reduction in telomere length in five participants (p=0.048) suggesting a delayed genomic effect following hypoxic conditions. Conversely, no statistically significant changes in methylation levels of BCL2 (p=0.438) and BMP2 (p=0.154) were reported between BL and 3MO samples. Overall, these results may provide further insights into the molecular mechanisms affected by hypoxic environmental conditions and their potential implications for male infertility.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
