November 18, 2016

expert comments about cryopreservation and tissue freezing

It has emerged that a girl who died from cancer last month won a legal fight to allow her to be cryogenically preserved following her death.

Dr Channa Jayasena, Clinical Senior Lecturer in Reproductive Endocrinology, Imperial College London, said:

“Human cells such as sperm, eggs, and pancreatic islets can be cryopreserved and used to treat patients with infertility and diabetes, respectively. Although experimental, organs such as ovaries can be cryopreserved and ‘auto-transplanted’ back to the same patient following cancer therapy. However, it is currently science fiction to suggest that a person could be brought back to life in the future even considering technological advances. In the UK, cryopreservation of human material is tightly regulated by the Human Fertility & Embryology Authority (HFEA) to ensure that material is not used without consent of the patient. I am concerned that the rights of vulnerable patients undergoing cryonics cannot be protected indefinitely. In summary, cryonics has risks for the patient, poses ethical issues for society, is highly expensive, but has no proven benefit. If this was a drug, it would never get approved.”

Prof. Clive Coen, Professor of Neuroscience, King’s College London, said:

“Despite the claims made by cryonics companies, they’ve failed to demonstrate that the extraordinary mass of tissue that constitutes the human brain can be protected by the antifreeze that they try to pump through the body after death. This tissue may indeed be safe once it’s in liquid nitrogen, but it will have already sustained incalculable and irreversible damage during the preparatory processes.

“Advocates of cryonics are unable to cite any study in which a whole mammalian brain (let alone a whole mammalian body) has been resuscitated after storage in liquid nitrogen.  Cryonics is based on wishful thinking rather than evidence. The companies selling the packages focus on safe storage of the tissue and openly admit that there’s no current procedure for resuscitation – but they gloss over all the damage that’s caused while they’re preparing the tissue for storage. The prospects of fixing that widespread damage at some future date is fanciful – and then there’s the fatal condition that prompted the vulnerable person to take time out waiting for a cure. To satisfy the vain hope of meeting loved ones, they’d all have to sign up – not so much a pyramid scheme as an iceberg scheme.”

Prof. Barry Fuller, Professor in Surgical Science & Low Temperature Medicine, UCL, said:

“Cryopreservation is a remarkable technology which allows us to store living cells, almost indefinitely, at ultra-low temperatures. It has many useful applications in day to day medicine, such as cryopreserving blood cells, sperm and embryos. We have learnt that to survive the process, cells have to be treated with special non-toxic antifreezes, and to be handled in very specific ways. In fact, if they are to survive, frozen cells are not ‘frozen’ – they must contain no ice crystals, which would otherwise invariably kill them. In fact to be able to survive, the water inside the cells needs to be drawn out – you can picture a raisin produced from a grape – raisins can be stored for long periods whereas grapes spoil within a few days. The ultra-low temperatures are needed to allow the cells to be able to survive the dehydration. Even so, uncontrolled dehydration is lethal to the cells. The way to optimise this for successful cryopreservation is to control the warming and cooling rates, which can be easily done for small tubes of cells or tissues – for example in cryopreserving embryos in infertility treatment.

“However, cryopreservation has not yet been successfully applied to large structures, such as human kidneys for transplantation, because we have not yet adequately been able to produce suitable equipment to optimise all the steps. This is why we have to say that at the moment we have no objective evidence that a whole human body can survive cryopreservation with cells which will function after rearming. There is ongoing research into these scientific challenges, and a potential future demonstration of the ability to cryopreserve human organs for transplantation would be a major first step into proving the concept, but at the moment, we cannot achieve that.”

Declared interests

None received