Cryobiology
Cryobiology is the branch of
Areas of study
At least six major areas of cryobiology can be identified: 1) study of cold-adaptation of
Cryopreservation in nature
Many living organisms are able to tolerate prolonged periods of time at temperatures below the freezing point of water. Most living organisms accumulate
Bacteria
Three species of bacteria,
Plants
Many plants undergo a process called
Animals
Invertebrates
The larvae of Haemonchus contortus, a nematode, can survive 44 weeks frozen at -196 °C.
Vertebrates
For the wood frog (Rana sylvatica), in the winter, as much as 45% of its body may freeze and turn to ice. "Ice crystals form beneath the skin and become interspersed among the body's skeletal muscles. During the freeze, the frog's breathing, blood flow, and heartbeat cease. Freezing is made possible by specialized proteins and glucose, which prevent intracellular freezing and dehydration."[6][7] The wood frog can survive up to 11 days frozen at -4 °C.
Other vertebrates that survive at body temperatures below 0 °C include painted turtles (
Hibernating Arctic ground squirrels may have abdominal temperatures as low as −2.9 °C (26.8 °F), maintaining subzero abdominal temperatures for more than three weeks at a time, although the temperatures at the head and neck remain at 0 °C or above.[11]
Applied cryobiology
Historical background
Cryobiology history can be traced back to antiquity. As early as in 2500 BC, low temperatures were used in Egypt in medicine. The use of cold was recommended by Hippocrates to stop bleeding and swelling. With the emergence of modern science, Robert Boyle studied the effects of low temperatures on animals.
In 1949, bull
Cryosurgery (intended and controlled tissue destruction by ice formation) was carried out by James Arnott in 1845 in an operation on a patient with cancer.
Preservation techniques
Cryobiology as an
A rule of thumb in hypothermic storage is that every 10 °C reduction in temperature is accompanied by a 50% decrease in
Cryopreservation of cells is guided by the "two-factor hypothesis" of American cryobiologist Peter Mazur[permanent dead link], which states that excessively rapid cooling kills cells by intracellular ice formation and excessively slow cooling kills cells by either electrolyte toxicity or mechanical crushing.[15] During slow cooling, ice forms extracellularly, causing water to osmotically leave cells, thereby dehydrating them. Intracellular ice can be much more damaging than extracellular ice.
For red blood cells, the optimum cooling rate is very rapid (nearly 100 °C per second), whereas for stem cells the optimum cooling rate is very slow (1 °C per minute). Cryoprotectants, such as dimethyl sulfoxide and glycerol, are used to protect cells from freezing. A variety of cell types are protected by 10% dimethyl sulfoxide.[16] Cryobiologists attempt to optimize cryoprotectant concentration (minimizing both ice formation and toxicity) and cooling rate. Cells may be cooled at an optimum rate to a temperature between −30 and −40 °C before being plunged into liquid nitrogen.
Slow cooling methods rely on the fact that cells contain few nucleating agents, but contain naturally occurring vitrifying substances that can prevent ice formation in cells that have been moderately dehydrated. Some cryobiologists are seeking mixtures of cryoprotectants for full vitrification (zero ice formation) in preservation of cells, tissues, and organs. Vitrification methods pose a challenge in the requirement to search for cryoprotectant mixtures that can minimize toxicity.
In humans
Human
Cryopreservation in humans with regards to infertility involves preservation of embryos, sperm, or oocytes via freezing. Conception, in vitro, is attempted when the sperm is thawed and introduced to the 'fresh' eggs, the frozen eggs are thawed and sperm is placed with the eggs and together they are placed back into the uterus or a frozen embryo is introduced to the uterus. Vitrification has flaws and is not as reliable or proven as freezing fertilized sperm, eggs, or embryos as traditional slow freezing methods because eggs alone are extremely sensitive to temperature. Many researchers are also freezing ovarian tissue in conjunction with the eggs in hopes that the ovarian tissue can be transplanted back into the uterus, stimulating normal ovulation cycles. In 2004, Donnez of Louvain in Belgium reported the first successful ovarian birth from frozen ovarian tissue. In 1997, samples of ovarian cortex were taken from a woman with Hodgkin's lymphoma and cryopreserved in a (Planer, UK) controlled-rate freezer and then stored in liquid nitrogen. Chemotherapy was initiated after the patient had premature ovarian failure. In 2003, after freeze-thawing, orthotopic autotransplantation of ovarian cortical tissue was done by laparoscopy and after five months, reimplantation signs indicated recovery of regular ovulatory cycles. Eleven months after reimplantation, a viable intrauterine pregnancy was confirmed, which resulted in the first such live birth – a girl named Tamara.[18]
Scientific societies
The
The Society for Low Temperature Biology was founded in 1964 and became a registered charity in 2003[21] with the purpose of promoting research into the effects of low temperatures on all types of organisms and their constituent cells, tissues, and organs. As of 2006, the society had around 130 (mostly British and European) members and holds at least one annual general meeting. The program usually includes both a symposium on a topical subject and a session of free communications on any aspect of low-temperature biology. Recent symposia have included long-term stability, preservation of aquatic organisms, cryopreservation of embryos and gametes, preservation of plants, low-temperature microscopy, vitrification (glass formation of aqueous systems during cooling), freeze drying and tissue banking. Members are informed through the Society Newsletter, which is presently published three times a year.
Journals
Cryobiology (publisher: Elsevier) is the foremost scientific publication in this area, with about 60 refereed contributions published each year. Articles concern any aspect of low-temperature biology and medicine (e.g. freezing, freeze-drying, hibernation, cold tolerance and adaptation, cryoprotective compounds, medical applications of reduced temperature, cryosurgery, hypothermia, and perfusion of organs).
Cryo Letters is an independent UK-based rapid communication journal which publishes papers on the effects produced by low temperatures on a wide variety of biophysical and biological processes, or studies involving low-temperature techniques in the investigation of biological and ecological topics.
Biopreservation and Biobanking (formerly Cell Preservation Technology) is a
Problems of Cryobiology and Cryomedicine (formerly 'Kriobiologiya' (1985-1990) and 'Problems of Cryobiology'(1991-2012) ) published by Institute for Problems of Cryobiology and Cryomedicine. The journal covers all topics related to low temperature biology, medicine and engineering. [22]
See also
References
- PMID 4371331.
- PMID 11222024.
- ^ "Food Safety Watch". Archived from the original on 2013-07-29. Retrieved 2013-09-12.
- ^ Rozell, Ned (May 30, 2009). "Scientist finds fungus gnats survive winter half-frozen". Anchorage Daily News. Archived from the original on 2009-09-23.
- ^ Rozell, Ned (October 17, 2007). "Alaska beetles survive 'unearthly' temperatures". Alaska Science Forum. Archived from the original on 2010-01-17. Retrieved 2009-10-26.
- ^ Kiehl, Katie. "Lithobates sylvaticus (Wood Frog)". Animal Diversity Web.
- ^ Fahrenthold, David A. (December 14, 2004). "Looking to frozen frogs for clues to improve human medicine". The Washington Post via The Seattle Times. Archived from the original on 2004-12-14.
- ^ "Untitled Document". Archived from the original on 2008-12-28. Retrieved 2009-10-27.
- ^ "FREEZE TOLERANT VERTEBRATES". Archived from the original on 2009-07-27. Retrieved 2009-10-26.
- ^ "Cryobiology". www.units.miamioh.edu.
- PMID 2740905. Archived from the original(PDF) on 2008-12-16. Retrieved 2008-11-23.
- ^ C. Polge, AU Smith, AS Parkes, Revival of spermatozoa Effective vitrification and dehydration at low temperatures Nature, 164 (1949), p. 666
- S2CID 198194950.
- PMID 10455972.
- PMID 330113.
- PMID 12623029.
- ^ "Freezing". Pacific Fertility Center. 2010. Archived from the original on 2010-05-26. Retrieved 2010-02-28.
- ^ "Livebirth after orthotopic transplantation of cryopreserved ovarian tissue" (PDF). J Donnez, M M Dolmans, D Demylle, P Jadoul, C Pirard, J Squifflet, B Martinez-Madrid, A Van Langendonckt. 2004. Archived from the original (PDF) on 2016-08-08. Retrieved 2015-01-02.
- ^ Darwin, Mike (1991). "Cold War: The Conflict Between Cryonicists and Cryobiologists". Cryonics. Alcor Life Extension Foundation. Retrieved 2009-08-24.
- ^ "Officers & Governors". Society for Cryobiology. Archived from the original on 2006-09-27. Retrieved 2010-03-13.
- Charity Commissionfor England & Wales No. 1099747)
- ^ "Problems of Cryobiology and Cryomedicine". Retrieved 28 May 2022.