Biological Basis of Impaired Fertility in Males Flashcards
what % of couples globally are affected primarily or contributingly by male infertility
4-6%
what can male infertility be classified as
- primary
- secondary
3 causes of male infertility subcategories
- congenital
- acquired
- idiopathic (unknown reason)
what are some causes of congenital factors of male infertility
what are they mostly caused by
- congenital factors of male infertility are mostly caused by genetic causes
common genetic causes of infertility - congenital bilateral absence of vas deferens associated with CF mutation
- Kallmann syndrome
- chromosome abnormalities such as Klinefelter syndrome
- Y-chromosome microdeletions
- anorchia (absence of testes => can’t produce sperm)
- cryptorchidism (testes undescended, present in lower abdominal cavity)
- Robertsonian translocation
- Androgen Insensitivity Syndrome (ie/ intersex)
- obstruction (in testes or in epididymis)
- genetic endocrinopathy
[acquired factors] what is most common correctable cause of infertility & what % of infertility cases can it occur in
(is an acquired factor)
- varicocele
~40% of all cases
what is varicocele
- enlargement of vein within scrotum that supplies testes
-> leading to reduced sperm concentration and quality
what are some acquired factors for male infertility (ie/ contribute to modifications in sperm production)
- direct trauma to testes
- testicular torsion
- germ cell tumours (within testes) (-> cause reduced sperm counts)
- recurrent urogenital (both urinary and genital organs) infections (-> can cause obstruction in epididymis)
- hypogonadotrophic hypogonadism
- inflammatory conditions (ie/ mumps, epididymitis)
- medications / chemotherapy
- systemic disease (ie/ metabolic syndrome, renal failure, autoimmunity)
- sexual dysfunction (this one not sperm modification but reduce ability of male to perform sexual intercourse) (eg/ erectile dysfunction)
what % of male infertility is caused by congenital factors
15%
what is the largest factor and up to _% of infertility cases in males
- idiopathic factors
- 50% of all cases
many __________ and _____ factors contribute to idiopathic causes (even though called unknown causes) of male infertility by reducing sperm quality and _________ _______ in males
- environmental factors
- ## lifestyle factors
- hormone regulation
stat of how many men will suffer from infertility in their life time _ in _
1 in 10
define primary male infertility
- the male has never been able to father a child
define secondary male infertility
- the male has been able to previously father a child, but can no longer
what does absence of vas deferens result in mechanically
- sperm unable to transit between testes and penis at ejaculation
(note: sperm made in testes -> sperm stored and mature in epididymis -> travel along vas deferens -> to ejaculatory duct -> that empties into urethra (at ejaculation)
(sperm mixed with various secretions at time of ejaculation)
what is Kallman syndrome (congenital - genetic cause of infertility)
- not enough sex hormone being made
- resulting in small testicles & reduced sperm counts
what is Klinefelter syndrome (congenital - genetic cause of infertility)
- men have extra X chromosome -> XXY
- have azoospermia ie/ no sperm -> infertile
explain degree of infertility for congenital genetic cause of infertility - Y chromosome microdeletions & Robertsonian translocation
- depending on where microdeletion is on Y chromosome -> determine severity of their infertility
- depending on where translocation occurring -> determine severity of their infertility
-> generally ranges from mild to moderate sperm defects
describe Androgen Insensitivity Syndrome (ie/ intersex)
- baby born genetically as male
- XY
- but present at birth with external female genitalia
- their testes located in position of where ovaries are
what are some idiopathic factors (environmental, lifestyle) that contributing to reduced male fertility and poor reproductive health
- obesity
- alcohol consumption
- recreational drug use
- poor diet
- endocrine disruptors
- radiation
- heat exposure
- physiological stress
- environmental pollutants
- industrial chemicals
can idiopathic environmental and lifestyle factors lead to modification of testes themselves & what does this lead to
- yes
- lead to changes in quality of sperm produced by testes
when we say lead to reduced sperm quality what is this resulting in (idiopathic factors??)
- reduced sperm counts
- reduced motility
- reduced morphology
- sperm viability
- reduced inability to respond to oxidative stress (low antioxidants)
for idiopathic factors, in most cases how can things return to normal
- when male removes themselves from factor they been exposed to eg/ lose weight, no tobacco
these lifestyle and environmental factors are not only influencing male reproductive potential (fertility) they are also influencing….
- male reproductive health more broadly
- not only seeing decline in sperm counts
- also seeing increase in instance of other reproductive disorders (eg/ testicular cancer, undescended testes, hypospadias - urethral orifice not located at penis tip, earlier onset puberty age)
there must be exposures to humans in last 50 years thats affecting infertility as well as reproductive health more broadly. true or false
true
