Spermatogonial stem cell
Function
The ability of a male to produce sperm cell is a basic condition for concievieng an offspring. The development of male gametes starts after birth at the seminiferous tubules, when a basal reservoir of male germ cell is created. These reserve male germ cells are called spermatogonia (sg.: spermatogonium). They represent the foundation of sperm cell production in the testis by balancing self-renewal and differentiation activity. When a man reaches the age of puberty, spermatogonia resume their division and start the process of spermatogenesis. Spermatogonia also replicate themselves to maintain their counts to supply the spermatogenesis during whole life of a man.
Characterization
Spermatogonia are the least mature cells in the process of spermatogenesis and can be found connected to Sertoli cells at the basement membrane of a seminiferous tubule (Pic. 1). Spermatogonia are diploid cells meaning that they contain full copy of man’s genetic information. Complete genetic information of any human is represented by 46 chromosomes, cell with 46 chromozomes are referred as diploid cells (2n). When spermatogonia resume mitotic division, the result is the gain of two identical diploid cells. One of these cells remains a spermatogonium, and the other one becomes a primary spermatocyte. Based upon a specific destiny of each spermatogonium (Pic. 2), there can be found 3 types.
1. Type Ad spermatogonia ("dark")
2. Type Ap spermatogonia ("pale")
3. Type B spermatogonia
Medical relevance
Undifferentiated spermatogonia can be also referred as unipotent spermatogonial stem cells (SSCs) due to some very specific qualities they possess. In particular, type A spermatogonia possess some special aspects of great medical importance in solving male cancer-induced infertility. When type A spermatogonia are transplanted into the seminiferous tubules of an infertile male, they can establish donor-derived spermatogenesis and produce sperm cells that transmit the donor haplotype to progeny. Additionally, when they are cultured in appropriate conditions, they can acquire pluripotency and differentiate into derivatives of the three embryonic germ layers.
An abnormal enlargement of the pampiniform venous plexus in the scrotum.
Complete absence of sperm in the ejaculate of a man.
The inability (that lasts more than 6 months) to develop or maintain an erection of the penis during sexual activity.
In the case of cryptorchidism one or both testes are absent from the scrotum. It is is the most common etiologic factor of azoospermy in the adult.
The pathological inability to ejaculate in males, with (orgasmic) or without (anorgasmic) orgasm.
A class of sexual disorders defined as the subjective lack of normal ejaculation.
A medical condition impairing the function of the thyroid.
The set of symptoms that result from two or more X chromosome in males.
A genetic condition where the primary symptom is a failure to start puberty or a failure to fully complete puberty.
Complete absence of sperm in the ejaculate due to testicular failure.
The male sex chromosomal disorder characterized by a spectrum of clinical presentations, ranging from ambiguous to normal male genitalia.
Semen with a low concentration of sperm and is a common finding in male infertility.
A medical term which describes a diminished functional activity of the gonads – the testes and ovaries.
Antibodies that bind to sperm, inhibiting their movement, stopping recognition and entry into the egg.
Cancer that develops in the testicles.
An inflammation of the prostate gland.
A condition in which a man has an unusually low ejaculate (or semen) volume.
Absence of sperm in the ejaculate despite normal spermatogenesis, caused by an obstruction of the genital tract.
An inflammation of the testes, involving swelling and heavy pains.
Emergency medical condition occurring when the spermatic cord twists and cuts off the testicle's blood supply.
Teratospermia is a condition characterized by the presence of sperm with abnormal morphology that affects fertility in males.
Male infertility diagnosis characterized by extremely low concentration of sperm in semen.
Male gonads which produce both sperm and androgens, such as testosterone, and are active throughout the reproductive lifespan of the male.
Process in which spermatozoa are produced from male primordial germ cells in testicles by way of mitosis and meiosis.
