2008/08/何積泓. reproductive aging a continuous process begins prior to birth a continuous...

2008/08/2008/08/何積泓何積泓

Reproductive AgingReproductive Aging

A continuous process begins prior to birthA continuous process begins prior to birth The depletion of non-growing follicles (NThe depletion of non-growing follicles (N

GFs)GFs) Ovarian dysfunction occurs many years prOvarian dysfunction occurs many years pr

ior to menopauseior to menopause Perimenopause: the number of remaining Perimenopause: the number of remaining

ovarian NGFs has dropped below a critical ovarian NGFs has dropped below a critical thresholdthreshold

MenopauseMenopause

Average 51 ± 8 yearsAverage 51 ± 8 years Initial endowment of NGFsInitial endowment of NGFs The rate of NGF depletionThe rate of NGF depletion A modelA model to better describe NGF to better describe NGF

depletiondepletion Previous model: the decay rate is Previous model: the decay rate is

exponential and biphasic (4 studies, n exponential and biphasic (4 studies, n = 6 ~ 52)= 6 ~ 52)

Human ovariesHuman ovaries

Elective unilateral or bilateral oophorectElective unilateral or bilateral oophorectomy (n = 45)omy (n = 45)

Organ donation agencies or national tissOrgan donation agencies or national tissue bank (n = 77)ue bank (n = 77)

Exclusion: chemotherapy, radiation, ovaExclusion: chemotherapy, radiation, ovarian surgery, ovarian pathology, cyst > 2rian surgery, ovarian pathology, cyst > 2cm diametercm diameter

Linear model, RLinear model, R22 = 0.50, = 0.50, 3.83M NGFs at birth, 2,290 NGFs at 51 y/3.83M NGFs at birth, 2,290 NGFs at 51 y/oo

Exponential model, RExponential model, R2 2 = 0.46, = 0.46, 2.75M NGFs at birth, 3,881 NGFs at 51 y/o2.75M NGFs at birth, 3,881 NGFs at 51 y/o

Biphasic exponential model, Biphasic exponential model, 1.15M NGFs at birth, 1,071 NGFs at 51 y/1.15M NGFs at birth, 1,071 NGFs at 51 y/oo

Power model, log(NGF#)=a(age)Power model, log(NGF#)=a(age)bb+c, R+c, R22=0.84 =0.84 0.52M NGFs at birth, 758 NGFs at 51 y/o0.52M NGFs at birth, 758 NGFs at 51 y/o

DiscussionDiscussion Previous exponential and biphasic Previous exponential and biphasic

model is unrealisticmodel is unrealistic Power model is simpler and betterPower model is simpler and better The NGF depletion is constantly The NGF depletion is constantly

accelerating accelerating 84% variability in NGF count is 84% variability in NGF count is

explained by ageexplained by age Other clinical markers may improve Other clinical markers may improve

the predictive powerthe predictive power