Androlog Mail
In response to the question posed by Sid Sarkar, Ph.D.
sarkars@mail.upstate.edu asking: 'Is there a current review on assay methods
of sperm chromatin damage? Is there a reliable commercial outfit where these
assays could be ordered?'
I wrote a review of current methods a couple of years ago, but it was
published in a book as a symposium talk and was not readily available to the
scientific audience. Evenson DP. 1999. Alterations and damage of sperm
chromatin structure and early embryonic failure. In: Towards Reproductive
Certainty: Fertility and Genetics Beyond 1999. (Jannsen R, Mortimer D,
Eds). Plenary Proceedings of the 11th World Congress on In Vitro
Fertilization and Human Reproductive Genetics. Parthenon Publishing Group
Ltd., New York/London. Chapter 15, pp. 313-329.
I will gladly send a reprint to anyone requesting it: scsadon@itctel.com
I recently wrote a new, comprehensive review on sperm chromatin damage, it's
sources and methods for detection for The Andrology Lab Corner. Evenson et
al., 2002. The Sperm Chromatin Structure Assay (SCSATM): Clinical Use for
Detecting Sperm DNA Fragmentation Related to Male Infertility and
Comparisons with Other Techniques. J of Andrology, Jan/Feb, Vol 23.
The article compares SCSATM data with TUNEL, COMET, in situ Nick Translation
assay, Acridine Orange Test (AOT), CMA3 and aniline blue data. In contrast
to these tests, the SCSATM has used the exact same procedure for the past
15+ years. We have measured thousands of animal and human sperm samples for
both fertility and toxicology evaluation. SCSATM data have shown a very
high correlation with heterospermic fertility trials in bulls (.94, p <.01)
and boars (.71, p < .01). SCSATM data are significantly correlated with
dose-response toxicology data for a variety of agents that affect different
germ cells types present at various stages of spermatogenesis and
spermiogenesis. The SCSATM is the most sensitive assay for measuring damage
in sperm DNA from low level X-radiation to the testes. Zinc deficient diets
cause SCSATM detectable DNA damage. The SCSATM detects sperm DNA damage in
men exposed to chemotherapy, drugs, pesticides, industrial chemicals,
cigarette smoking and environmental pollution. Therefore, our laboratory
has an extensive database on thousands of SCSATM measurements that are
published in over 100 manuscripts. This is in contrast to the other assays
mentioned above that are not standardized and do not have years of research
to support them.
In logical progression from the above research, in the last few years we
have turned our studies almost exclusively to measuring human semen samples.
We and a few other laboratories trained in the SCSATM technique by us, have
measured thousands of human semen samples. Because of our concern for
strict standardization of the assay, we have trademarked SCSATM, and will
serve as the reference laboratory for both the procedure and for the
software used in analysis. Our WEB page gives more details:
www.SCSAdiagnostics.com
Grace Centola commented: (androlog, Oct 4. Re: Sperm chromatin damage) 'the
SCSA is not yet approved by the FDA for use as a clinical test'. However,
we are working toward FDA approval and an initial application has been made.
In a recent conference call with two FDA officials in the specific area that
the SCSATM will be evaluated, I received permission (for promotional
advertising) to use the disclaimer: 'For investigational use only. Not for
use in diagnostic procedures'. This is in contrast to 'Experimental use
only', since the SCSATM has been used in experiments for almost 20 years for
both animals and humans and the protocol is 'set in concrete'. Thus, we are
now in the investigational phase and with our current multi-institutional,
clinical fertility studies hope to secure full FDA approval in the near
future. SCSATM Diagnostics, Inc. is of course CLIA certified.
In sharp contrast to other chromatin tests, we have established a current
threshold of < 1% probability of a successful term pregnancy when >30% of
sperm in an ejaculate demonstrate a SCSATM defined DNA fragmentation. This
threshold was seen in in vivo male factor fertility studies (Evenson et
al.,1999. Human Reprod 14:1039; Spano et al., 2000. Fert Steril 73:43), a
pilot in vitro fertilization study (Larson et al., 2000. Human Reprod
15:1717) and in current unpublished data on >700 IVF cases (in part: Virro
et al, 2001. IFFS, Melbourne, abst.) If this threshold continues to be
validated, the SCSATM could well provide a powerful assessment for the
idiopathic infertile male. Data will soon be published that shows the age
related intersect line for age and the SCSATM >30% DNA Fragmentation Index
(DFI) is in the upper 40's. Apparently, the SCSATM can reveal very
important information about men in their mid-40's and above who had children
by a previous marriage, have motile and morphologically normal sperm but the
couple now has had multiple failed in vivo or ART attempts. A physician
might assume that since the man has had previous proven fertility and has
normal sperm parameters then the man must be fertile. But we have cases
where 'older' men have a DFI index over the 30% threshold, and therefore the
man's fertility potential is suspect. In some of these cases, a sperm donor
has resulted in a solution to the idiopathic infertility.
As well pointed out by Mark Perloe (androlog, Oct 4) 'questions on clinical
application abound'. He asks, 'if no obvious reversible factor is
identified and addressed, should the test be repeated three months later to
confirm the result prior to a formal treatment recommendation?' Data
published in the above referenced 'Georgetown fertility study' (Evenson et
al.,1999. Human Reprod 14:1039), a 'semen quality, over time' study
(Evenson et al., 1991. Reprod Tox 5:115), and the 'effects of fever study'
(Evenson et al., 2000. J Androl 21:739) clearly show that the level of DNA
fragmentation can change quickly for the better or worse in a short amount
of time. This is an indicator of something out of the ordinary happening as
the SCSATM is in fact the most constant measure compared to the classical
parameters (Evenson et al., 1991. Reprod Tox 5:115). Thus, if the first
sample has a high DNA Fragmentation Index, it is highly recommended that
another sample be measured two to three months later. If there has been no
change in lifestyle or exposure and the DFI is still high, then the patient
should be counseled that this might be a permanent condition.
With regard to Dr. Perloe's second question, 'Can this test help predict
response to varicocele repair'? A study is now underway to collect semen
samples prior to and following repair. We hypothesize that the SCSATM data
will improve. Whether heat applied to mammalian testes has anything to do
with potential heat from a varicocele is not known. However, we have
published data from several experiments applying low levels of external heat
to bull testes (with Dick Saacke) and mice testes, and the changes in
chromatin structure are dramatic in a dose/time dependent manner.
Finally, with regard to Sid Sarkar's second question, 'is there a reliable
commercial outfit where these assays could be ordered'? Our laboratory is
the inventor and developer of the SCSATM for the past 20 years. Our
commercial arm is SCSATM Diagnostics, Inc. whose WEB site
www.SCSAdiagnostics.com provides information on how the SCSATM can be
ordered.
Donald P. Evenson, Ph.D.
Distinguished Professor
Department of Chemistry and Biochemistry
South Dakota State University
Brookings, SD 57007
Phone: 605-692-5938
FAX: 605-692-9739
Email: scsadon@itctel.com
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