MACS – sperm selection using magnetic activated cell sorting. What is it?
MACS is Assisted Reproduction Technology with sperm that allows sperm with the best characteristics to be selected. Choosing the healthiest ones and eliminating the weakest which would not achieve fertilization increases the possibility of pregnancy. In what cases should this technique be used?
All of it is explained by our experts in 3on1 #IVFANSWERS:
- Volodymyr Boretskyi – Embryologist at Parens IVF Center
- Dr Ruth Sánchez – Gynecologist at PreGen, The Reproduction Unit at Clinica Vistahermosa
- Dr Magdalena Golańska – Wróblewska – Fertility Specialis at Salve Medica
Answer from embryologist Boretskyi
Assisted reproductive techniques are used worldwide with increasing frequency because these techniques greatly benefit couples who have problems trying to conceive. Studies of infertile couples have demonstrated that a male factor plays a significant role in infertility. Basic semen analyses and standard methods for sperm selection, such as density gradient centrifugation and swim-up techniques, have been used with good results. However, to improve the diagnosis and treatment of male infertility, basic semen analyses should be complemented with tests that provide data on sperm functionality. Sperm DNA fragmentation has recently become the most widely studied complementary test. Studies have demonstrated that sperm cells with genetic defects are directly associated with infertility.
One of the early markers of apoptosis is the loss of membrane integrity, which leads to phospholipid phosphatidylserine externalization (a molecule with a high affinity for annexin V). Therefore, annexin V conjugated with magnetic microspheres, which are exposed to a magnetic field in an affinity column, can separate apoptotic from non-apoptotic sperm. This procedure is called magnetic activated cell sorting (MACS).
MACS is an efficient method that can avoid apoptotic sperm during selection. MACS efficiently reduces sperm DNA fragmentation levels and effectively separates apoptotic from non-apoptotic spermatozoa. This selection leads to an improvement in sperm quality and functionality. There were positive changes in the pregnancy rates when sperm was selected using MACS.
The use of MACS alone or associated with DGC leads to fewer sperm with DNA damage. MACS alone or before DGC also culminate with higher percentage of normal sperm morphology. However, they promote decreased motility, being a possible option only for ICSI fertilisation.
To conclude, this method is suitable for patients with high incidence of apoptotic sperm, patients with low rate of egg fertilisation after IVF, ICSI or after recurring failure of IVF treatment cycles without an apparent cause.
Answer from Dr Sánchez
This method allows us to separate apoptotic sperm (which is programmed for cell death) from the non-apoptotic and viable. The principal on which these columns are based on is that apoptotic sperm expresses phosphatidylserine in the outer membrane and this has an affinity for a protein called annexin.
We incubate the selected sperm with annexin coated with magnetic micro-particles and make it pass through a column where a magnetic field has been applied. The apoptotic sperm will be retained in the column while the non-apoptotic will be passed through it without being retained. This non-apoptotic sperm fraction is the one which is used in assisted reproduction treatments, increases fertilisation capacity of the sperm and allows to achieve a higher gestation rate, approximately between 10 and 15%.
This technology can be applied to any type of a patient – but mainly to infertility patients with high DNA fragmentation in their sperm, patients with repeated miscarriages without other identified causes and also to patients with at least one previous cycle or with poor embryo quality which is not due to the oocytes.
Answer from Dr Magdalena Golanska-Wroblewska
MACS is an acronym for magnetic activated cell sorting. With this technique, we can select sperm with proper quality and without sperm damage. So it raises our chances for pregnancy and life-birth. We can use fresh or frozen semen. It depends on our abilities and possibilities. We can use it for an in vitro procedure and for insemination. The only proper condition that semen should meet is a quality condition – at least 10 million of spermatozoids.
As in many medical procedures, we should have indications for using MACS. And here we have the following: recurrent assisted reproductive techniques failures, inappropriate semen test results, recurrent miscarriages (by definition, it means 3 or more miscarriages in early pregnancy) and poor embryo quality that is not connected with the quality of eggs.
If you choose MACS for your ART procedure, the preparation is the same as before a standard semen test. The decision about using MACS depends on sperm quality, egg quality and financial abilities of a couple. You should always discuss it with your doctor or embryologist.