Sperm protamine 1/protamine 2 ratios are related to in vitro fertilization pregnancy rates and predictive of fertilization ability.
OBJECTIVE
To evaluate whether aberrant sperm P1/P2 ratios are predictive of abnormal fertilizing ability and are related to in vitro fertilization (IVF) outcome.


METHODS
Prospective case-control study.


METHODS
University-based infertility and IVF clinic.


METHODS
Forty-three male infertility patients with an abnormally reduced P1/P2 ratio, 251 patients with a normal P1/P2 ratio, and 121 patients with an abnormally elevated P1/P2 ratio.


METHODS
Human IVF, the sperm penetration assay (SPA), and sperm protamine quantification via nuclear protein extraction, gel electrophoresis, and densitometry analysis.


METHODS
Sperm P1/P2 ratios; P1 and P2 quantities; SPA scores; and IVF-fertilization, embryo-quality, pregnancy, delivery, and spontaneous-abortion rates.


RESULTS
Standard IVF fertilization rates and SPA scores were significantly reduced in patients with abnormally low and high P1/P2 ratios. In vitro fertilization embryo quality was comparable between these groups, but pregnancy rates were significantly reduced in patients with abnormally reduced P1/P2 ratios.


CONCLUSIONS
The P1/P2 ratio has a significant relationship to sperm fertilization ability. The relationship between protamines and fertilization ability is not understood but may be either a reflection of generalized abnormalities during spermiogenesis or an indication of protamine deficiency acting as a regulator or checkpoint of spermatogenesis.
Aoki
Vincent W
VW
Andrology and IVF Laboratories, University of Utah School of Medicine, Salt Lake City, Utah 84108, USA.
Liu
Lihua
L
Jones
Kirtly P
KP
Hatasaka
Harry H
HH
Gibson
Mark
M
Peterson
C Matthew
CM
Carrell
Douglas T
DT
D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data*; D006801:Humans; D007248:Infertility, Male / Q000175:diagnosis / Q000453:epidemiology / Q000378:metabolism* / Q000628:therapy*; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D011379:Prognosis; D011446:Prospective Studies; D011479:Protamines / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013094:Spermatozoa / Q000378:metabolism*; D013223:Statistics as Topic; D016896:Treatment Outcome; D014589:Utah / Q000453:epidemiology
D015415:Biomarkers; C082073:PRM1 protein, human; D011479:Protamines; C068621:protamine 2