Evaluation of sperm nuclear integrity in patients with different percentages of decapitated sperm in ejaculates

Abstract

The decapitated sperm defect is a rare type of teratozoospermia responsible for male infertility. Spermatozoa from patients affected by this syndrome are used for intracytoplasmic sperm injection (ICSI) although little is known about their DNA integrity. This study evaluated sperm nuclear alterations in four patients and ten fertile men (control group). Sperm samples were examined by light, transmission electron and high-magnification contrast microscopy and analysed after terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling, aniline blue staining and fluorescence in-situ hybridization. Spermatozoa from patients presented varying degrees of decapitation, along with morphological and ultrastructural head abnormalities. Whereas the proportion of spermatozoa with fragmented DNA and numerical chromosome abnormalities was similar in patients 1-3 and controls, the percentage of spermatozoa with hypocondensed chromatin was higher in patients 1-3 than in fertile men. Patient 4 presented a distinct phenotype, with an increased proportion of flagellated spermatozoa with DNA strand breaks as well as increased aneuploidy and diploidy rates compared with controls and with patients 1-3. No successful pregnancy resulted from ICSI although embryos were obtained for three patients. The morphological defects and the nuclear alterations observed in spermatozoa of patients with the decapitated sperm syndrome may have contributed to ICSI failures.

Biallelic SUN5 Mutations Cause Autosomal-Recessive Acephalic Spermatozoa Syndrome

“…So far, more than 20 cases have been reported, and its genetic cause in humans remains unknown. [2][3][4][5][6][7][8][9][10][11][12][13][14] Semen from infertile men with this syndrome consistently shows nearly 100% abnormally shaped spermatozoa. The majority is comprised of headless tails, as well as a very small proportion of intact spermatozoa with an abnormal head-tail junction and also a few tailless heads.…”

Headless spermatozoa in infertile men

“…Therefore, the question was whether the detached tails and heads were still alive and had normal function. First, using a Feulgen reaction to determine whether any DNA existed or to determine the DNA fragmentation level in spermatozoa could aid tentative diagnosis (Rondanino et al., ). Second, both hypo‐osmotic swelling and zona‐free hamster egg tests (Oehninger, Franken, & Ombelet, ; Talwar & Hayatnagarkar, ) could identify if most headless spermatozoa were functionally normal.…”

Sperm with fibrous sheath dysplasia and anomalies in head-neck junction: focus on centriole and centrin 1

“…Rondanino et al. (), analysing the nuclear integrity in patients with different percentages of decapitated spermatozoa, found that hypocondensed chromatin is increased, and, in one case only, fragmented DNA is associated with concomitant numerical chromosomal abnormalities.…”

“…Spermatozoa with defect in head–tail attachment showed low fertility potential; the arrest of early embryo development can be a consequence of centriole defective function (Chemes et al., ; Rawe et al., , ) or low chromatin and DNA quality (Rondanino et al., ); in a few cases, the pregnancies were obtained probably because the injected sperm head was equipped with a normal centriolar area (Gambera et al., ; Porcu et al., ). In conditions such as DFS, the reproductive outcome is poor, with low fertilisation and very few babies born (Dávila Garza & Patrizio, ).…”