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Updated: Dec 12, 2025
U-Shaped Horizontal Swimming Technique for Preparing High-Quality Sperm with Low DNA Fragmentation Index
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Discordance between human sperm quality and telomere length following differential gradient separation/swim-up
Ana Catarina Lopes1,2, Pedro Fontes Oliveira1,3,4, Soraia Pinto5
1Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal.
Background:
Strong evidence has suggested an important role of telomeres in meiosis, fertilization, and embryo development.
Purpose:
To determine if sperm telomere length (STL) in sperm purified by differential gradient centrifugation followed by swim-up (selected STL) is correlated with sperm quality and clinical outcomes.
Methods:
Relative selected STL was assessed by quantitative polymerase chain reaction (Q-PCR) in 78 consecutive assisted reproductive technology (ART) treatments during 2017. Statistical analyses were performed in the totality of patients, and in normozoospermic and non-normozoospermic patients. These included correlations between selected STL and sperm quality parameters, embryological parameters (multivariable linear regression), and clinical parameters (multivariable logistic regression).
Results:
No significant correlations were found between selected STL and sperm quality in the total population. However, selected STL was significantly correlated with total sperm count (r = 0.361; P = 0.039) and sperm DNA fragmentation-post-acrosomal region pattern (r = - 0.464; P = 0.030) in normozoospermic patients. No relation was observed between selected STL and clinical outcomes in any clinical group.
Conclusions:
As the correlations observed in normozoospermic patients were not representative of the whole heterogeneous population, differences in the sperm characteristics of the study population may lead to discrepant results when evaluating the association of STL with sperm quality. Since the total population selected STL was not related with sperm quality and with clinical outcomes, results do not support the use of selected STL measurement to evaluate the reproductive potential of the male patient or to predict the success rates of ART treatments.
