Is it possible, in an unbiased and clinical relevant way, to determine the number of viable acrosome-intact human spermatozoa in ejaculates and to use this as a measure of fertility chances?
Image cytometry enables easy and unbiased quantification of viable acrosome-intact spermatozoa and it correlates with semen quality and fertility status.
The presence of the acrosome and its ability to respond to physiological inducers (e.g. progesterone) in the female reproductive tract at the appropriate time and place is required for fertilization. However, the available assays are labor intensive and therefore not used clinically.
Washed semen samples and capacitated swim-up fractions from volunteers were used to develop the assay. Subsequently washed ejaculates from patients in fertility treatment (n = 156), proven fertile men (n = 54) and volunteers (n = 10) were assessed to evaluate the number of acrosome-intact spermatozoa in the ejaculate (acrosomal status) and compared to other semen parameters, fertility status, fertility treatments and pregnancy rates.
Image cytometry was used to assess the fluorescence intensity of Pisum sativum agglutinin and Propidium iodide.
The assay was validated by inducing the acrosome reaction in swim-up-purified and capacitated spermatozoa with progesterone and ionomycin, and in repeated acrosomal status measurements of washed ejaculates a small coefficient of variation (3.7%) was observed. Men with poor semen quality had fewer viable acrosome-intact spermatozoa in the ejaculate (P = 0.0012; median 32.6% vs. 49.3%). A large proportion (44%) of normozoospermic men from infertile couples had less than the observed median fraction (46%) of viable acrosome-intact spermatozoa in the ejaculate. Furthermore, the total number of viable acrosome-intact spermatozoa was significantly lower among men with male factor infertility compared to fertile men (median 35 vs. 97 mill, P = 1 × 10-7). Men from couples going through one or more ICSI cycles had significant fewer viable acrosome-intact spermatozoa than men from couples who only underwent IUI (P = 0.002; 44.4% vs. 62.0%) and the fraction of viable acrosome-intact spermatozoa appeared better than classical semen parameters in classifying whether or not couples needed ICSI. A positive, although non-significant, tendency toward ongoing pregnancy with an increasing number of viable acrosome-intact spermatozoa was observed (P = 0.2).
N/A.
Even larger cohorts of infertile couples are needed to substantiate the clinical application of the assay in regard to estimation of fertility potential of an individual.
The presented assay makes it possible to measure the number of acrosome competent spermatozoa in an ejaculate in a standardized manner and hence may serve as a new biomarker for male fertility. Few spermatozoa in an ejaculate are acrosome competent and it might be a valuable measure when evaluating male reproductive function.
This work was supported by grants from the Innovation Fund Denmark. M.G. and S.K. work at ChemoMetec, which produces the image cytometer used in the study, M.G. hold shares in the company. The other authors have no conflict of interest.
Human reproduction (Oxford, England). 2018 Jan 02 [Epub ahead of print]
Dorte Louise Egeberg Palme, Anders Rehfeld, Anne Kirstine Bang, Kristiana Alexandrova Nikolova, Søren Kjærulff, Morten Rønn Petersen, Janni Vikkelsø Jeppesen, Martin Glensbjerg, Anders Juul, Niels E Skakkebæk, Søren Ziebe, Niels Jørgensen, Kristian Almstrup
University Department of Growth and Reproduction, Section GR-5064, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark., ChemoMetec A/S, Gydevang 43, DK-3450 Allerød, Denmark., The Fertility Clinic, Section 4071, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.