Current Status of Vitrification of Human Sperm

Current status of Vitrification of human sperm is either not clear or even we can say it isn’t helpful for IUI or IVF. By and by Vitrification of Oocyte, zygote, embryo and blastocyst  is ordinarily performed to treat infertility. In present theme “Current status of Vitrification of human sperm” we will talk about present situation  related to the Vitrification of human sperm for IUI or IVF.

Vitrification can be defined as the transition of water directly from the liquid phase into an amorphous phase or glass.  While avoiding the formation of crystalline ice (Fahy et al., 1984).

Regularly used cryopreservation techniques enable ice to form  inside and outside the cell.  And it also works  for  human sperm. Furthermore, there is likewise a precarious increase  in the solute concentration  during the traditional cryopreservation  of cell or tissue. Both ice and high solute concentration can harm the cell and tissue osmotically and genetically.

Vitrification is a process in which cells as well as the entire solution  is solidified  without the formation  of ice.   The solidification  of entire solution is accomplished by sudden decrease in the temperature of solution. Which does not allow ice crystal to form. Subsequently entire solution convert into a strong glass like structure.

Oocyte, zygote, embryo and blastocyst freezing by Vitrification method for cryopreservation have

been used successfully for many years.  But till date Vitrification process is still lacking for sperms preservation.

Vitrification of human sperm  – Current status

1. Till date only limited trial has been  made to freeze human sperm by vitrification.
2. Very small quantity (2 – 20 micro liter) has been successfully preserved  on copper loop or on grid of electron microscope.
3. Saved amount of human sperm by vitrification was not adequate for IUI or IVF reason.
4. Till date sperms on the open copper loop has been  preserved  only by Vitrification. In this way there is reasonable possibility of cross contamination through liquid nitrogen.
5. Some trial has been made to preserve human sperm by Vitrification  without permeable cryo-preservative. But remain non-conclusive.
6.  Oocyte, zygote, embryo and blastocyst freezing by Vitrification method for cryopreservation have  been used for many years.  But not for the sperm.
7. Vitrification solution used  to vitrify  oocyte, zygote, embryo or blastocyst  is not suitable to vitrify human sperm.   Concentrations of cryoprotectant required are very high  which  is not suitable  to preserve sperm.  High concentration of  cryoprotactant and other salts  are potentially, and often actually, harmful to cells  including sperm. They affect the sperm and  cells  osmoticaly as well genetically.
8. Classical Vitrification requires a high percentage of permeable  cryoprotectants in medium (30–50%, compared to 5–7% with  slow freezing) and is unsuitable for the Vitrification of spermatozoa due to the lethal osmotic effect.  Shape and size of the  sperm head could be the factors that define the cryosensitivity  of the cell.

How Vitrification will be better from conventional cryopreservation of human sperm

1. The motility of cryopreserved and thawed spermatozoa  normally falls to approximately 50% of the motility before freezing in case of conventional cryopreservation.   Vitrification should give better outcome.   
2. Traditional cryopreservation results in intracellular ice crystal development. Which can harm the cell wall and structure of cell. While extracellular development of ice crystal cause increment in the salt concentration. Which can obviously result in osmotic and hereditary harm of cell.
3. Practically speaking, current outcomes are satisfactory.  Yet the techniques are still by and large moderately troublesome and simplification  is desirable.
4. Compared to the slow-freezing method, vitrification has economic advantages.  Since there is no necessity of any advanced freezing  instruments.
5. It has been suggested that  Vitrification may be less traumatic to the meiotic spindle than  slow freezing. And may also have less effect on cell physiology.   Thus, Vitrification seems more perfect and  standard method of cryopreservation  for gametes as well as tissues.

Conflict of interest  —-  Till now we did not notice any  conflict of interest.

Acknowledgements  —  Frozen Cell Team is in a nonstop procedure to find out an investigation on preservation of human sperm. We are in an endeavor  to discover a superior procedure to human sperm preservation by different  technique.

Funding  —  100 %  funded by Frozen Cell.  We don’t accept any funding from any outside source.

References –

• Dr Eugenia Isachenko,  Vol 6. No 2. 191–200 Reproductive BioMedicine Online
• Reproductive Medicine Unit, University of Schleswig-Holstein at Luebeck, Ratzburger Alle 160, 23538 Luebeck, Germany
• Andrologia, M. Slabbert1, S.S. du Plessis2 & C. Huyser1
• Wikipedia
• Method of Enzymology, 2003,  Pampa Ray, Marin van Heel.

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