Sperm pathology: a step beyond descriptive morphology. Origin, characterization and fertility potential of abnormal sperm phenotypes in infertile men

Abstract

Sperm pathology is presented as the discipline of characterizing structural and functional deficiencies in abnormal spermatozoa. This concept complements that of sperm morphology mainly concerned with the appearance of spermatozoa. These two notions collaborate in providing correlations of prognostic value with sperm fertilizing capacity, explaining the mechanisms of sperm inefficiency, suggesting strategies to improve fertilization and opening a door to molecular genetic studies. Phenotypes of genetic origin involving sperm heads, flagella and the neck region are presented describing their clinical manifestations, sperm structure, cytochemistry and genetic background. When available, animal models are used to highlight possible genetic mechanisms. Sperm pathologies secondary to andrological conditions or environmental factors are described, stressing the non-specific nature of the sperm response to noxious agents. The available literature on the prognostic value of sperm pathologies in ICSI is also reviewed. Flagellar anomalies bear a good prognosis, but those affecting the acrosome, sperm chromatin and the neck region entail an increasing chance of failure, which highlights the differential roles played by specific sperm components in fertilization, implantation and early embryonic development. A final discussion is devoted to genetic counselling and the risks involved in using immotile or abnormal spermatozoa in assisted reproduction.

Head-base bending and disjointed spermatozoa in the emu (Dromaius novaehollandiae): A morphological comparison of two closely related defects

“…The areas of 11 incomplete condensation were generally positioned towards the outside of the bend and displayed coarse granules and intervening spaces, similar to regions of uncondensed chromatin described in mammalian sperm [33][34][35]. This phenomenon is considered to be a morphological manifestation of chemical or molecular abnormalities in the condensation process [33,34,36] resulting in single stranded DNA being formed as opposed to the more stable double stranded form.…”

“…A number of other mammalian sperm defects, such as acephalic sperm, decapitated sperm and the flexed head defect, are believed to originate from eccentric implantation of the head and neck, or structural deficiencies of the neck region [33]. Similarly Chemes and Rawe [35,39] reported on sperm with misaligned head-midpiece junctions, stating that different degrees of incorrect alignment results in either acephalic sperm (the most severe form of the defect) or sperm where the head is misaligned. They further ascribed the misalignment to the lack or abnormal implantation of the centrioles during the early stages of spermiogenesis.…”

Lower sperm DNA fragmentation after r-FSH administration in functional hypogonadotropic hypogonadism

“…In addition, Greco et al in 2005 reported a clinical pregnancy rate (PR) of 0 % with microinjection of testicular sperm in patients with DNA fragmentation levels in semen >15 %, as measured by TdTmediated-dUTP nick-end labeling (TUNEL) [19]. Higher percentage of fragmented chromatin in a seminal sample is associated with a reduced pregnancy and implantation rates after conventional IVF and it is predictive of failure of embryo development in couples undergoing ICSI cycles [17] confirming the "paternal effect" of sperm DNA on the embryo development, as demonstrated by several other authors [10,41,61].…”

Types of Pathozoospermia in Men With Infertility in Marriage Аnd/or Disorders of Reproductive System

“…В боль-шинстве случаев (5 из 7 образцов) она сочеталась с олиго- астенотератозооспермией, в 1 наблюдении -с астено-тератозооспермией и еще в 1 -с астенозооспермией. Наличие большого количества живых, но неподвижных сперматозоидов может указывать на структурные де-фекты их жгутиков [7]. Повышенное количество не-подвижных и мертвых сперматозоидов при нормальной концентрации может свидетельствовать о патологии придатка яичка [8].…”