Telomere Length in Pig Sperm Is Related to In Vitro Embryo Development Outcomes

Telomere length has attracted much interest as a topic of study in human reproduction; furthermore, the link between sperm telomere length and fertility outcomes has been investigated in other species. This biomarker, however, has not been much explored in other animals, such as pigs, and whether it is related to sperm quality and fertility outcomes remains unknown. The present work aimed to determine the absolute value of telomere length in pig sperm, as well as its relationship to sperm quality parameters and embryo development. Telomere length was determined through quantitative fluorescence in situ hybridization (qFISH) in 23 pig sperm samples and data were correlated to quality parameters (motility, morphology, and viability) and in vitro fertilization outcomes. We found that the mean telomere length in pig sperm was 22.1 ± 3.6 kb, which is longer than that previously described in humans. Whilst telomere length was not observed to be correlated to sperm quality variables (p > 0.05), a significant correlation between telomere length and the percentage of morulae 6 days after in vitro fertilization was observed (rs = 0.559; 95%C.I. = (−0.007 to 0.854); p = 0.047). Interestingly, this correlation was not found when percentages of early blastocysts/blastocysts (rs = 0.410; 95%C.I. = (−0.200 to 0.791); p = 0.164) and of hatching/hatched blastocysts (rs = 0.356; 95%C.I. = (− 0.260 to 0.766); p = 0.233) were considered. Through the separation of the samples into two groups by the median value, statistically significant differences between samples with shorter telomeres than the median and samples with longer telomeres than the median were found regarding development to morula (11.5 ± 3.6 vs. 21.8 ± 6.9, respectively) and to early blastocyst/blastocysts (7.6 ± 1.4 vs. 17.9 ± 12.2, respectively) (p < 0.05). In the light of these results, sperm telomere length may be a useful biomarker for embryo development in pigs, as sperm with longer telomeres lead to higher rates of morulae and blastocysts.

The association of male infertility with telomere length: A case control study

To study the relevance of sperm telomere length and infertility in men. : Our case-control study included twenty-five males in couple with sub-fertility/infertility (test group) and twenty five healthy males (control group) with proven paternity in the age group 25 to 35 years. The Absolute Sperm Telomere length (aSTL) was measured by real-time PCR. We investigated whether any significant difference in the aSTL value existed between the groups and analysed the relationship between aSTL and other sperm parameters.The mean (SE) aSTL recorded in the infertile cases was significantly shorter than for the control group being 140.60 (6.66) Kb/genome and 239.63 (12.32) Kb/genome respectively (p &#60;0.001) A weak correlation was eminent between aSTL kb/genome and the total sperm count mil/ml (rho= 0.04, p - 0.86), progressive sperm motility (rho= - 0.02, p=0.934) and sperm viability (rho= - 0.07 p=0.741) in the infertile group. The measurement of aSTL by real-time PCR is a simple and rapid method that offers further paramount information with respective to the quality of sperm. It is befitted for epidemiological studies, hence opening new perspectives in the evaluation of male infertility. Limitations - Our study was confined to men aged between 25 and 35 years. Further comparative studies are needed to explore the significance of STL and infertility in older males. Additional studies will help illumine the significance of aSTL as a prognostic biomarker in assisted reproduction.

Telomere Distribution in Human Sperm Heads and Its Relation to Sperm Nuclear Morphology: A New Marker for Male Factor Infertility?

Infertility is a problem affecting an increasing number of couples worldwide. Currently, marker tests for male factor infertility are complex, highly technical and relatively subjective. Up to 40% of cases of male factor infertility are currently diagnosed as idiopathic therefore, there is a clear need for further research into better ways of diagnosing it. Changes in sperm telomere length have been associated with infertility and closely linked to DNA damage and fragmentation, which are also known to be related to infertility. However, telomere distribution is a parameter thus far underexplored as an infertility marker. Here, we assessed morphological parameters of sperm nuclei in fertile control and male factor infertile cohorts. In addition, we used 2D and 3D fluorescence in situ hybridization (FISH) to compare telomere distribution between these two groups. Our findings indicate that the infertile cohort sperm nuclei were, on average, 2.9% larger in area and showed subtle differences in sperm head height and width. Telomeres were mainly distributed towards the periphery of the nuclei in the control cohort, with diminishing telomere signals towards the center of the nuclei. Sperm nuclei of infertile males, however, had more telomere signals towards the center of the nuclei, a finding supported by 3D imaging. We conclude that, with further development, both morphology and telomere distribution may prove useful investigative tools in the fertility clinic.