Tuesday, February 23, 2010

Sperm Fragmentation Assay : is it Useful?

It's just an additional test  that may  give additional insight . Like many  test in infertility  it delivers results in relative terms  i.e one may have a REDUCED chance of fertility if the test is abnormal (as opposed to all or nothing) .   Having said so most still decide to use their own sperm even if the test is abnormal and take their (albeit reduced)  chances . This is the reason why  i  do not use the test as much  because i don't offer it to people who  under no circumstances would use donor sperm . For others the test helps as it may offer  some insight in why a cycle did not work.  so if you go for he route of donor sperm at least you know that you made the decision based on scientific evidence as opposed of trial and error. A couple of scientific articles below.

Reprod Biomed Online. 2010 Jan;20(1):114-124. Epub 2009 Nov 10.

Sperm chromatin structure assay and classical semen parameters: systematic review.

Castilla JA, Zamora S, Gonzalvo MC, Luna Del Castillo JD, Roldan-Nofuentes JA, Clavero A, Björndahl L, Martínez L.
Reproduction Unit, Hospital 'Virgen de las Nieves', E-18014 Granada, Spain; Sperm Bank CEIFER, Granada, Spain.
The present study is based on a PubMed search and compares the clinical validity of classical semen parameters (CSP) and the sperm chromatin structure assay (SCSA) in different clinical contexts. The PubMed database was searched using keywords on the sperm diagnostic test for pregnancy in three clinical scenarios: (i) couples attempting to conceive; (ii) couples who had been attempting to conceive for 12months without success; and (iii) couples treated with intrauterine insemination (IUI). There was a considerable heterogeneity among the studies included. For couples attempting to conceive following a SCSA that produced an abnormal result, the likelihood of male factor infertility ranged from a pre-test value of 7.5% to a post-test value of 32.1% [95% confidence interval (CI) 15.7-54.5], while after CSP with an abnormal result, the post-test probability was 17.3% (95% CI 11.8-24.5). For a pre-test prevalence of male factor infertility of 50%, the post-test probability of male factor infertility after an abnormal test is very similar for both SCSA and CSP. In couples treated with IUI, the clinical validity of SCSA is higher than that of sperm morphology alone, but not enough to introduce SCSA as a test in male infertility work-up. Copyright © 2009 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Toxicol Appl Pharmacol. 2005 Sep 1;207(2 Suppl):532-7.

Environmental toxicants cause sperm DNA fragmentation as detected by the Sperm Chromatin Structure Assay (SCSA).

Evenson DP, Wixon R.
HCLD, Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA. scsa@brookings.net
Studies over the past two decades have clearly shown that reproductive toxicants cause sperm DNA fragmentation. This DNA fragmentation can usually be detected prior to observing alterations of metaphase chromosomes in embryos. Thus, Sperm Chromatin Structure Assay (SCSA)-detected DNA damage is viewed as the molecular precursor to later gross chromosome damage observed under the light microscope. SCSA measurements of animal or human sperm consist of first obtaining a fresh or flash frozen neat semen sample in LN2 or dry ice. Samples are then sent to a SCSA diagnostic laboratory where the samples are thawed, diluted to approximately 1-2 x 106 sperm/ml, treated for 30 s with a pH 1.2 detergent buffer and then stained with acridine orange (AO). The low pH partially denatures DNA at the sites of DNA strand breaks and the AO-ssDNA fluoresces red while the AO-dsDNA fluoresces green. Flow cytometry measurements of 5000 sperm/sample provide statistically robust data on the ratio of red to green sperm, the extent of the DNA fragmentation and the standard deviations of measures. Numerous experiments on rodents treated with reproductive toxicants clearly showed that SCSA measures are highly dose responsive and have a very low CV. Different agents that act on germ cells at various stages of development usually showed sperm DNA fragmentation when that germ cell fraction arrived in the epididymis or ejaculate. Some of these treated samples were capable of successful in vitro fertilization but with frequent embryo failure. A 2-year longitudinal study of men living a valley town with a reported abnormal level of infertility and spontaneous miscarriages and also a seasonal atmospheric smog pollution, showed, for the first time, that SCSA measurements of human sperm DNA fragmentation were detectable and correlated with dosage of air pollution while the classical semen measures were not correlated. Also, young men spraying pesticides without protective gear are at an increased risk for elevated sperm DNA fragmentation. Extensive DNA fragmentation probably cannot be repaired by the egg and the spontaneous abortion rate is approximately 2x higher if a man has more than 30% of sperm showing DNA fragmentation. DNA fragmentation is an excellent marker for exposure to potential reproductive toxicants and a diagnostic/prognostic tool for potential male infertility.

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