Sperm DNA integrity in patients with varicocele: relationships between DNA fragmentation and bulk semen parameters
Alargkof , V1; Kersten, L2; Stanislavov, RS3; Nikolova, V3; Kamenov, Z4; Nikolinakos, P1
1: Medical University - Sofia, Bulgaria ; 2: University of Essex, United Kingdom; 3: Genika Genetic and Medico-Diagnostic Laboratory, Bulgaria; 4: Alexandrovska University Hospital/ Medical University - Sofia, Bulgaria
Objective: Sperm nuclear DNA fragmentation is associated with negative influence on embryo development, lower pregnancy rates and an approximately double risk ratio (RR) for miscarriages. The current study was designed to examine and compare the levels of DNA fragmentation in 2 groups of patients with varicocele: patients with normozoospermia and patients with oligoasthenoteratozoospermia (OAT), which can both be encountered on standard sperm analysis in patients with varicocele. Of note, there is evident association between varicocele and increased levels of DNA fragmentation and DNA integrity assays are argued to be independent predictors of sperm quality.
Materials and Methods: Standard semen analysis was performed according to the criteria of the European Society of Human Reproduction and Embryology and the Nordic Association for Andrology (ESHRE-NAFA 2010). DNA fragmentation analysis was carried out using the Halosperm® kit. The total sample contained 29 males: the control group consisted of men with normal genital examination and unknown fertility status (n=10), group 1 (G1) consisted of men with clinically diagnosed varicocele (by palpation and Doppler ultrasound examination) and normozoospermia (n=9) and group 2 (G2) consisted of men with clinically diagnosed varicocele and OAT (n=9). Data analysis was performed using the R software for statistical computing.
Results: DNA fragmentation was found to be higher in patients with OAT (G2) (43.78±30.78). Increased levels could also be identified in the normozoospermia group (G1) (21.22±3.93) when compared to the control group (11.4±1.35). The p value between controls and G1 was p <0.001, between controls and G2 p<0.001 and between G1 and G2 p=0.008.
Conclusions: The higher levels of DNA fragmentation in patients with OAT could reflect the advanced effect of varicocele on spermatogenesis. The fact that increased levels of DNA fragmentation can be found in varicocele patients with normozoospermia could reinforce the notion that DNA fragmentation assays are important to perform as additional tests in the work-up of varicocele patients. It also raises the question of whether this group of patients could be offered operative treatment, bearing in mind the risk for spontaneous abortions and the fact that DNA fragmentation levels seem to decrease after varicocelectomy.
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