Information for Clinicians about Sperm DNA Fragmentation

The genetic integrity of the spermatozoan is essential for normal embryo development. A high level of DNA fragmentation in sperm cells may represent a cause of male infertility that conventional examinations - sperm concentration, motility analysis, morphology assessment - cannot detect.  Results reported in the scientific literature have shown that regardless of the assisted reproductive technology used, an elevated level of DNA fragmentation above the critical threshold will significantly compromise the possibility of a successful pregnancy.

• high sperm DNA fragmentation does not appear to affect fertilisation or the first or second embryo cleavage stages
  
• high sperm DNA fragmentation can affect embryo cleavage once the paternal genome is switched on, and subsequent blastocyst development
  
• DNA fragmentation levels are closely correlated with IUI, IVF and ICSI miscarriage and pregnancy rates
  
• DNA fragmentation is significantly higher in subfertile men.
  
• men with poor semen parameters are more likely to have high DNA fragmentation
  
• high sperm DNA fragmentation is also found in men with normal semen parameters
  

Advantages of the Sperm DNA Fragmentation test
This test provides a reliable analysis of sperm DNA integrity that may help to identify men who are at risk of failing to initiate a healthy ongoing pregnancy. Information about sperm DNA integrity may help in the clinical diagnosis, management and treatment of male infertility and may be of prognostic value in assessing outcome of assisted conception treatment

High Rates of Sperm DNA Fragmentation and Pregnancy
Normal, healthy pregnancies do occur in couples where the male partner has a high percentage of sperm with fragmented DNA, although the chances are significantly reduced, as the percentage of sperm bearing low levels of DNA fragmentation is much lower. Embryos derived from sperm whose DNA is highly fragmented have a poor prognosis. Evidence suggests that this could result in initiation of apoptosis and mutations resulting in blastocyst arrest, miscarriage, abnormalities in the offspring and an increased susceptibility to childhood cancer. Protection against high DNA fragmentation may be afforded by younger oocytes which are much more efficient at DNA repair of defective sperm than older oocytes, so a couple coming for assisted conception treatment where the sperm DNA fragmentation level is high has a better prognosis if his partner is young.
 
Causes of Sperm DNA Fragmentation
A major causative factor for sperm DNA damage is oxidative stress. Other factors include abnormalities in the regulation of apoptosis, or defects in topoisomerase activity. Increased sperm DNA fragmentation is associated with:

• infection
  
• leucocytospermia
  
• sperm cytoplasmic droplets
  
• febrile illness
  
• elevated testicular temperature
  
• diet
• drug use
  
• cigarette smoking
• exposure to environmental and occupational pollutants
• advanced age
  
• varicocoele

Indications for Male Patients who may benefit from the Test

• unexplained infertility
• arrested embryo development
• poor blastocyst development
• multiple failed IVF/ICSI treatment
• recurrent miscarriage in partner
• advanced age
• varicocoele
• poor semen parameters
  
• exposure to harmful substances

Treatment
Some causes of DNA fragmentation cannot be treated, but if the damage is caused by free radicals, then a change in lifestyle and a diet designed to protect against oxidative stress may help reduce the levels of DNA fragmentation in some of these cases. Treatment of infection with antibiotics would also be expected to reduce DNA fragmentation. There is some evidence to show that varicocoele repair may improve sperm DNA integrity.  Initiatives to reduce the levels of fragmentation can be assessed by undertaking a second test three months after the first. Initial reports suggest that DNA damage occurs at the post-testicular level, so that testicular sperm may have a healthier DNA integrity than ejaculated sperm. Furthermore, studies show that ICSI may be a more effective treatment than IVF for sperm with a high DNA fragmentation.

What is the DNA fragmentation test?
This test is an effective method for measuring thousands of sperm in an ejaculate. Sperm are stained with a fluorescent probe that interacts with the DNA molecule. The fluorescence signal changes when the DNA is fragmented, and this is monitored using a flow cytometer. The SCSA® test has been developed over the last 20 years and is CLIA approved.


Results

The results are reported showing 3 statistical categories of fertility potential :

DNA Fragmentation Index (%DFI; % sperm cells containing damaged DNA)

< 15% DFI = excellent fertility potential
> 15 to < 30% DFI = good fertility potential
> 30% DFI = fair to poor fertility potential*

The statistically significant DFI threshold for subfertility has been established at > 30%.
Normal full-term pregnancies are possible with an elevated DFI, but the higher the level of fragmentation, the greater the incidence of reduced term pregnancies and miscarriage.

High DNA stainability (HDS; % cells with immature chromatin)

< 15% HDS = normal
> 15% HDS = above normal

Immature chromatin can be measured by high DNA stainability (HDS) and is associated with asyngamy and poor IVF fertilisation rates when it exceeds 15%.

Additional information downloads:

Sperm DNA Fragmentation and Aneuploidy/Sample Information Sheet and Request Form (Word doc, 56Kb)

REFERENCES
Aitken RJ, De Iuliis GN and McLachlan RI (2009). Biological and clinical significance of DNA damage in the male germ line. Int J Androl 32(1):46-56

Varghese AC, Bragais FM, Mukhopadhyay D, Kundu S, Pal M, Bhattacharyya AK and Agarwal A (2009) Human sperm DNA integrity in normal and abnormal semen samples and its correlation with sperm characteristics. Andrologia 41(4):207-15

Tunc O, Thompson J and Tremellen K (2009) Improvement in sperm DNA quality using an oral antioxidant therapy. Reprod Biomed Online 18(6):761-8.

Moskovtsev SI, Lecker I, Mullen, JB, Jarvi k, Willis J, White J and Lo KC (2009) Cause-specific treatment in patients with high sperm DNA damage resulted in significant DNA improvement.  Syst. Biol. Reprod. Med. 55(2):109-15

Agarwal A, Makker K and Sharma R (2008) Clinical relevance of oxidative stress in male factor infertility: an update. Am J Reprod Immunol. 59(1):2-11

Armand Zini, Jason M. Boman, Eric Belzile and Antonio Ciampi (2008) Sperm DNA damage is associated with an increased risk of pregnancy loss after IVF and ICSI: systematic review and meta-analysis Human Reproduction  23(12):2663-2668

Lewis SE, Agbaje I, Alvarez J. (2008) Sperm DNA tests as useful adjuncts to semen analysis Syst Biol Reprod Med. May-Jun;54(3):111-25

Tarozzi N, Bizzaro D, Flamigni C and Borini A (2007) Clinical relevance of sperm DNA damage in assisted reproduction. Reprod Biomed Online 14(6):746-57.

Evenson D and Wixon R (2006) Meta-analysis of sperm DNA fragmentation using the sperm chromatin structure assay. Reprod. Biomed. Online 12 (4): 466-472

Boe-Hanson GB, Fedder J, Ersboll AK and Christensen P (2006) The sperm chromatin structure assay as a diagnostic tool in the human fertility clinic.
Human Reproduction  21(6):1576-1582

Smith R, Kaune H, Parodi D, Madariaga M, Rios R, Morales I and Castro A (2006) Increased sperm DNA damage in patients with varicocele: relationship with seminal oxidative stress. Human Reprod. 21(4):986-993.

Greco E, Scarselli F, Iacobelli M, Rienzi L, Ubaldi F, Ferrero S, Franco G, Anniballo N, Mendoza C and Tesarik J (2005) Efficient treatment of infertility due to sperm DNA damage by ICSI with testicular spermatozoa. Human Reproduction 2005 20(1):226-230

Guerin P, Matillon, C, Bleau G, Levy R and Menezo, Y (2005) Impact of sperm DNA fragmentation on
 ART outcome. Gynecol. Obstet. Fertil. 2005 Sep;33(9):665-8.

Evenson DP, Wixon R (2005) Environmental toxicants cause sperm DNA fragmentation as detected by the Sperm Chromatin Structure Assay (SCSA(R)). Toxicol Appl Pharmacol. 2005 Sep 1;207(2 Suppl):532-7

Check JH, GrazianoV, Cohen R, Krotec, J and Check ML (2005) Effect of an abnormal sperm chromatin structural assay (SCSA) on pregnancy outcome following (IVF) with ICSI in previous IVF failures. Arch Androl. 2005 Mar-Apr;51(2):121-4.

Bungum M, Humaida P, Spano M, Jepson K, Bungum L and Giwercman A (2004) The predictive value of sperm chromatin structure assay (SCSA) parameters for the outcome of intrauterine insemination, IVF and ICSI Human Reproduction 19 (6): 1401-1408

Virro MR, Larson-Cook KL, Evenson DP (2004) Sperm chromatin structure assay (SCSA) parameters are related to fertilization, blastocyst development, and ongoing pregnancy in in vitro fertilization and intracytoplasmic sperm injection cycles. Fertil Steril.81(5):1289-95

Sills ES, Fryman JT, Perloe M, Michels KB, Tucker MJ (2004) Chromatin fluorescence characteristics and standard semen analysis parameters: correlations observed in andrology testing among 136 males referred for infertility evaluation. J Obstet Gynaecol. 2004 Jan;24(1):74-7.

Gandini L, Lombardo F, Paoli D, Caruso F, Eleuteri P, Leter G, Ciriminna R, Culasso F, Dondero F, Lenzi A, Spano M. (2004) Full-term pregnancies achieved with ICSI despite high levels of sperm chromatin damage. Hum Reprod. 2004 Jun;19(6):1409-17

Fischer MA, Willis J and Zini A (2003) Human sperm DNA integrity: correlation with sperm cytoplasmic droplets. Urology 61(1):207-11