Semen cryopreservation

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Semen cryopreservation (commonly called sperm banking or sperm freezing) is a procedure to preserve sperm cells. Semen can be used successfully indefinitely [ citation needed ] after cryopreservation. It can be used for sperm donation where the recipient wants the treatment in a different time or place, or as a means of preserving fertility for men undergoing vasectomy or treatments that may compromise their fertility, such as chemotherapy, radiation therapy or surgery. It is also often used by trans women prior to medically transitioning in ways that affect fertility, such as feminizing hormone therapy and orchiectomies.

Contents

Freezing

The most common cryoprotectant used for semen is glycerol (10% in culture medium). Often sucrose or other di-, trisaccharides are added to glycerol solution. Cryoprotectant media may be supplemented with either egg yolk or soy lecithin, with the two having no statistically significant differences compared to each other regarding motility, morphology, ability to bind to hyaluronate in vitro, or DNA integrity after thawing. [1]

Additional cryoprotectants can be used to increase sperm viability and fertility rates post-freezing. Treatment of sperm with heparin binding proteins prior to cryopreservation showed decreased cryoinjury and generation of ROS. [2] The addition of nerve growth factor as a cryoprotectant decreases sperm cell death rates and increased motility after thawing. [3] Incorporation of cholesterol into sperm cell membranes with the use of cyclodextrins prior to freezing also increases sperm viability. [4]

Semen is frozen using either a controlled-rate, slow-cooling method (slow programmable freezing or SPF) or a newer flash-freezing process known as vitrification. Vitrification gives superior post-thaw motility and cryosurvival than slow programmable freezing. [5] This current technique, invented by the Japanese, is used in the best centers around the world. It is extremely fast (-23000°C/min), so as a result it avoids the appearance of small ice crystals, preventing the "knife" effect.

Thawing

Thawing at 40 °C seems to result in optimal sperm motility. On the other hand, the exact thawing temperature seems to have only minor effect on sperm viability, acrosomal status, ATP content, and DNA. [6] As with freezing, various techniques have been developed for the thawing process, both discussed by Di Santo et al. [7]

Refreezing

In terms of the level of sperm DNA fragmentation, up to three cycles of freezing and thawing can be performed without causing a level of risk significantly higher than following a single cycle of freezing and thawing. This is provided that samples are refrozen in their original cryoprotectant and are not going through sperm washing or other alteration in between, and provided that they are separated by density gradient centrifugation or swim-up before use in assisted reproduction technology. [8]

Effect on quality

Some evidence suggests an increase in single-strand breaks, condensation and fragmentation of DNA in sperm after cryopreservation. This can potentially increase the risk of mutations in offspring DNA. Antioxidants and the use of well-controlled cooling regimes could potentially improve outcomes. [9]

In long-term follow-up studies, no evidence has been found either of an increase in birth defects or chromosomal abnormalities in people conceived from cryopreserved sperm compared with the general population. [9]

See also

Related Research Articles

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<span class="mw-page-title-main">Intracytoplasmic sperm injection</span> In vitro fertilization procedure

Intracytoplasmic sperm injection is an in vitro fertilization (IVF) procedure in which a single sperm cell is injected directly into the cytoplasm of an egg. This technique is used in order to prepare the gametes for the obtention of embryos that may be transferred to a maternal uterus. With this method, the acrosome reaction is skipped.

Cryobiology is the branch of biology that studies the effects of low temperatures on living things within Earth's cryosphere or in science. The word cryobiology is derived from the Greek words κρῧος [kryos], "cold", βίος [bios], "life", and λόγος [logos], "word". In practice, cryobiology is the study of biological material or systems at temperatures below normal. Materials or systems studied may include proteins, cells, tissues, organs, or whole organisms. Temperatures may range from moderately hypothermic conditions to cryogenic temperatures.

<span class="mw-page-title-main">Embryo transfer</span> Method of assisted reproduction

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<span class="mw-page-title-main">Sperm bank</span> Facility that purchases, stores and sells human semen

A sperm bank, semen bank, or cryobank is a facility or enterprise which purchases, stores and sells human semen. The semen is produced and sold by men who are known as sperm donors. The sperm is purchased by or for other persons for the purpose of achieving a pregnancy or pregnancies other than by a sexual partner. Sperm sold by a sperm donor is known as donor sperm.

Terms oligospermia, oligozoospermia, and low sperm count refer to semen with a low concentration of sperm and is a common finding in male infertility. Often semen with a decreased sperm concentration may also show significant abnormalities in sperm morphology and motility. There has been interest in replacing the descriptive terms used in semen analysis with more quantitative information.

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Sperm washing is the process in which individual sperms are separated from the semen. Washed sperm is used in artificial insemination using the intrauterine insemination (IUI) technique and in in vitro fertilization (IVF). It may also be used to decrease the risk of HIV transmission by an HIV-positive male, in which case the washed sperm is injected into a female using an artificial insemination technique.

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<span class="mw-page-title-main">Semen analysis</span> Scientific analysis of semen

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Semen quality is a measure of male fertility, a measure of the ability of sperm in semen to accomplish fertilization. Semen quality involves both sperm quantity and quality. Semen quality is a major factor for fertility.

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<span class="mw-page-title-main">Cryopreservation</span> Process to preserve biological matter

Cryopreservation or cryoconservation is a process where biological material - cells, tissues, or organs - are frozen to preserve the material for an extended period of time. At low temperatures any cell metabolism which might cause damage to the biological material in question is effectively stopped. Cryopreservation is an effective way to transport biological samples over long distances, store samples for prolonged periods of time, and create a bank of samples for users. Molecules, referred to as cryoprotective agents (CPAs), are added to reduce the osmotic shock and physical stresses cells undergo in the freezing process. Some cryoprotective agents used in research are inspired by plants and animals in nature that have unique cold tolerance to survive harsh winters, including: trees, wood frogs, and tardigrades.

Semen extender is a liquid diluent which is added to semen to preserve its fertilizing ability. It acts as a buffer to protect sperm cells from their own toxic byproducts, as well as protecting the sperm from cold shock and osmotic shock during the chilling and shipping process. The extender allows the semen to be shipped to the female, rather than requiring the male and female to be near to each other. Special freezing extender use also allows cryogenic preservation of sperm, which may be transported for use, or used on-site at a later date.

Ovarian tissue cryopreservation is cryopreservation of tissue of the ovary of a female.

Cryopreservation of embryos is the process of preserving an embryo at sub-zero temperatures, generally at an embryogenesis stage corresponding to pre-implantation, that is, from fertilisation to the blastocyst stage.

<span class="mw-page-title-main">Sperm Chromatin Structure Assay</span>

Sperm Chromatin Structure Assay (SCSA) is a diagnostic approach that detects sperm abnormality with a large extent of DNA fragmentation. First described by Evenson in 1980, the assay is a flow cytometric test that detects the vulnerability of sperm DNA to acid-induced denaturation DNA in situ. SCSA measures sperm DNA fragmentation attributed to intrinsic and extrinsic factors and reports the degree of fragmentation in terms of DNA Fragmentation Index (DFI). The use of SCSA expands from evaluation of male infertility and subfertility, toxicology studies and evaluation of quality of laboratory semen samples. Notably, SCSA outcompetes other convention sperm DNA fragmentation (sDF) assays such as TUNEL and COMET in terms of efficiency, objectivity, and repeatability.

<span class="mw-page-title-main">LGBT reproduction</span> Theoretical biological reproduction by LGBT people

LGBT reproduction refers to lesbian, gay, bisexual, and transgender (LGBT) people having biological children by means of assisted reproductive technology. It is distinct from LGBT parenting, which is a broader cultural phenomenon including LGBT adoption. In recent decades, developmental biologists have been researching and developing techniques to facilitate same-sex reproduction.

References

  1. ↑ Reed, ML; Ezeh, PC; Hamic, A; Thompson, DJ; Caperton, CL (2009). "Soy lecithin replaces egg yolk for cryopreservation of human sperm without adversely affecting postthaw motility, morphology, sperm DNA integrity, or sperm binding to hyaluronate". Fertility and Sterility. 92 (5): 1787–1790. doi: 10.1016/j.fertnstert.2009.05.026 . PMID   19539916.
  2. ↑ Patel, M; Gandotra, VK; Cheema, RS; Bansal, AK; Kumar, A (2016). "Seminal Plasma Heparin Binding Proteins Improve Semen Quality by Reducing Oxidative Stress during Cryopreservation of Cattle Bull Semen". Asian-Australasian Journal of Animal Sciences. 29 (9): 1247–1255. doi:10.5713/ajas.15.0586. PMC   5003984 . PMID   26954172.
  3. ↑ Saeednia, S; Bahadoran, H; Amidi, F; Asadi, MH; Naji, M; Fallahi, P; Nejad, NA (2015). "Nerve growth factor in human semen: Effect of nerve growth factor on the normozoospermic men during cryopreservation process". Iranian Journal of Basic Medical Sciences. 18 (3): 292–299. doi:10.22038/IJBMS.2015.4134. PMC   4414996 . PMID   25945243.
  4. ↑ Purdy, PH; Graham, JK (2004). "Effect of cholesterol-loaded cyclodextrin on the cryosurvival of bull sperm". Cryobiology. 48 (1): 36–45. doi:10.1016/j.cryobiol.2003.12.001. PMID   14969680.
  5. ↑ Vutyavanich, T; Piromlertamorn, W; Nunta, S (2010). "Rapid freezing versus slow programmable freezing of human spermatozoa". Fertility and Sterility. 93 (6): 1921–1928. doi: 10.1016/j.fertnstert.2008.04.076 . PMID   19243759.
  6. ↑ Calamera, JC; Buffone, MG; Doncel, GF; Brugo-Olmedo, S; de Vincentiis, S; Calamera, MM; Storey, BT; Alvarez, JG (2010). "Effect of thawing temperature on the motility recovery of cryopreserved human spermatozoa". Fertility and Sterility. 93 (3): 789–794. doi: 10.1016/j.fertnstert.2008.10.021 . hdl: 11336/14695 . PMID   19059590.
  7. ↑ Di Santo, M; Tarozzi, N; Nadalini, M; Borini, A (2012). "Human Sperm Cryopreservation: Update on Techniques, Effect on DNA Integrity, and Implications for ART". Advances in Urology. 2012: 854837. doi: 10.1155/2012/854837 . PMC   3238352 . PMID   22194740.
  8. ↑ Thomson, LK; Fleming, SD; Barone, K; Zieschang, JA; Clark, AM (2010). "The effect of repeated freezing and thawing on human sperm DNA fragmentation". Fertility and Sterility. 93 (4): 1147–1156. doi: 10.1016/j.fertnstert.2008.11.023 . PMID   19135665.
  9. 1 2 Kopeika, J.; Thornhill, A.; Khalaf, Y. (2014). "The effect of cryopreservation on the genome of gametes and embryos: principles of cryobiology and critical appraisal of the evidence". Human Reproduction Update. 21 (2): 209–227. doi: 10.1093/humupd/dmu063 . PMID   25519143.
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