Male Infertility

Male Infertility

Male Infertility

Infertility in the male may be due to insufficient sperm production, sub-optimal motility and/or progression, abnormal morphology or a combination of these parameters. The male reproductive organs namely the testes are responsible for the production, nourishment and transportation of spermatozoa and for the production and secretion of the male sex hormones necessary for the maintenance of the male reproductive system.
Male infertility may be a consequence of a collection of factors mostly associated with endocrine, mechanical/physical, infectious-related, lifestyle dependent, immunological and genetic reasons.
1. Endocrine
The main hormone responsible for the production of sperm is called testosterone and this is produced in the testes by either of two separate pathways. The latter are mediated by hormonal events enabled by two glands in the brain namely the hypothalamus and the hypophysis. Any derangement in the normal functioning of the two glands will compromise the production of sperm. Moreover, other hormones or chemical substances which the male organism produces or administered exogenously may interfere with the normal secretion and subsequent functioning of testosterone production.
2. Mechanical/physical
Testicular trauma or torsion may result in compromised functioning of the duct (vas deferens) whose muscular reflexive contraction propels sperm forward from the testes to the urethra. The vas deferens may also become obstructed due to infection or indeed may completely be absent due to a congenital defect, impairing normal ejaculation of spermatozoa. Certain males may manifest retrograde ejaculation a condition where semen is redirected into the urinary bladder rather than being ejaculated through the urethra. Approximately 3-5% of all male infants present undescended testes (also known as cryptorchidism) a condition when one or both of the testes remain hidden in the lower part of the abdomen (more commonly seen in males born prematurely). Individuals who are not treated promptly (before puberty) can suffer irreversible damage of testicular function. A considerable number of males worldwide suffer from sexual dysfunction. Old age, high blood pressure and diabetes can cause impotence mainly due to decreased production of testosterone, reduced blood flow and impaired neurological function. Certain men fail to control ejaculation the occurrence of which precedes sexual intercourse or materializes shortly thereafter. Although the cause of premature ejaculation is not well understood it is believed that both psychological and biological factors contribute to it.
3. Infectious –related
Both bacterial and viral infections affecting the genital tract may contribute to male infertility by impairing the dynamic process of spermatogenesis reducing sperm count, motility and progression. Besides the adverse influence on reproductive function, infections may potentially cause permanent obstruction of the tubular network necessary for the transport of spermatozoa within the testes or affect the prostate gland (prostatitis) a condition which if not treated promptly its effects become permanent. The commonest complication in adult males is contractual infection of mumps leading to orchitis (inflammation of one or both testes) a condition which damages the normal function of testicular cells leading to compromised sperm production and viability.
4. Lifestyle-dependent
The lifestyle of a man has a direct effect on his fertility potential. The standpoint of Genesis is that the prime cause of the decline in the reproductive capacity of the human male associates with dietary pollution a global phenomenon whose effects are extending to alarming dimensions. Growth hormones, toxic preservatives and steroids consumed from animal products, fish, fruit and vegetables all contribute to a reduced male fertility.
Other associated reasons are exposure to environmental hazards and toxins such as pesticides, paint and radioactivity, excessive and chronic alcohol abuse, prolonged use of narcotics and cigarette smoking, excessive workout combined with the use of anabolic steroids and to industrial pollutants such as heavy metals (e.g. cadmium, lead and mercury).
5. Immunological
It is estimated that approximately 10% of all infertile men are manifesting auto-immune anti-sperm antibodies while this rate is 1% for individuals with proven fertility. Antibodies are protein molecules produced by blood cells and are used by the immune system to fight foreign substances such as bacteria and viruses. The reasons why certain male populations raise antibodies against their own spermatozoa have not been elucidated as yet. A prevalence is noted in men who suffered major testicular infections, torsions or cancer, diagnosed with a condition known as varicocele (dilated testicular veins resulting in temperature increase), received reversal vasectomy or a congenital testicular abnormality. Antibodies attach to the sperm causing them to clump together in different orientations rendering them incapable to penetrate the cervical mucus and gain access to the egg as motility and progression are compromised. The use of assisted reproduction techniques such as in vitro insemination or direct sperm injection into the egg are advised to circumvent the adverse effects of anti-sperm antibodies.
6. Genetic
Partial or total obstruction of the genital tract can be the result of a congenital (present at birth) defect or a consequence of a genetic predisposition. Almost all males for example presenting Cystic Fibrosis manifest obstructive azoospermia because they are born without a Vas Deferens (muscular ducts within which sperm is conveyed in the testes). Several inherited conditions which may also be expressed as syndromes (collection of signs) compromise sperm production due to undeveloped testicular genesis and/or testicular dysfunction. Chromosomal or single gene derangements which may be the result of a parent of origin inheritance or indeed a de novo (new) mutation at the time of fertilization and very early embryogenesis constitute pivotal genetic roles in male infertility. The commonest examples of such conditions are;
Kallmann’s Syndrome; a condition characterized by delayed or absent puberty and an impaired sense of smell. It affects the production of hormones which mediate sexual development. Males presenting this condition have impaired testicular function due to the impeded secretion of the reproductive hormones (FSH and LH) and therefore testosterone production. Affected males do not develop secondary sex characteristics at puberty for this reason.
Myotonic Dystrophy; a multi-system disorder associated with muscular and endocrine defects integrating into testicular and tubular atrophy, impotence, oligospermia and azoospermia. More than 75% of the affected male population is subfertile or completely infertile.
Sickle Cell; a condition characterized with testicular failure, impotence and delayed or impaired sexual development. Affected males have significantly reduced ejaculate volume, sperm count and motility due to testosterone insufficiency while the number of morphologically normal spermatozoa is markedly sub-optimal presumably due to a local hypoxia effect.
Klinefelter Syndrome; results when a male acquires an additional X chromosome in his genotype (47XXY). It is characterized by permanent testicular damage associated with fibrotic tissue, smaller sized testes, and abnormalities in the reproductive endocrine system leading most of the times to azoospermia. Contemporary assisted reproduction techniques such as the use of surgically retrieved spermatozoa followed by direct egg injection (ICSI) could be advantageous to a number of Klinefelter syndrome patients while for the largest majority the only solution to parenthood will be the use of donor sperm.
Kartagener’s Syndrome; is an inherited condition which causes the transposition of organs and derangements in the respiratory tract. In the human male the syndrome associates with ultra structural defects in the tails of the spermatozoa leading to complete absence of vitality. Such patients may benefit from surgical sperm extraction and subsequent egg fertilization in vitro to achieve a pregnancy.
Chromosome Rearrangements; involve one or more change (deletion, duplication, inversion or translocation) in the normal structure of a chromosome changing thereby the specific order of genes. Such rearrangements account for a genetic imbalance leading to either early embryonic arrest or an early miscarriage.
Y Chromosome Microdeletion; the Y chromosome is the smallest chromosome of all and curries only 220 genes most important of which are those accounting for the sex determining region. Deletions in specific gene sequences lead to compromised sperm counts and azoospermia.