There Tissue Bank of theNiguarda Hospital in Milan it is a national center of excellence, one of only five of this type active in Italy (the others are located in Turin, Verona, Cesena and Siena). It is a structure capable of conservation 52,000 square centimetres of tissue, a vital resource for treating patients affected by serious burns. The importance of this healthcare facility is evident in these days: the hospital staff have indeed welcomed 11 patients involved in the recent tragedy of the «Le Constellation» club in Crans-Montana, Switzerland. To understand how this rescue machine works and what happens biologically to the human body in these cases, we interviewed the Dr. Marta Cecilia Toscabiotechnologist responsible for the Niguarda Tissue Bank, part of the SSD Tissue Bank and Tissue Therapy – director Dr. Giovanni Sesana, and Antonella Marisa Citterioanesthetist and plastic surgeon responsible for the SS Burns Center which belongs to the SC Reconstructive Plastic Surgery, Large Burns and Complex Integumental Lesions. In addition to them, the team is made up of 3 other biologists/biotechnologists, 1 doctor for the laboratory part and support for sampling and 12 doctors for sampling.
What exactly is a Tissue Bank?
It’s about non-profit structures who deal with the entire process inherent to the fabrics starting from withdrawal on cadaver donors, to theirs processing in controlled contamination laboratories (environments close to sterility – so to speak cleaner than an operating room) and which includes strict quality controls. This is followed by conservation in the most suitable conditions for the different fabrics. The skin, for example, can be preserved at –80°C for 2 years or in nitrogen vapors for 5 years. When quality controls give a positive result, for example absence of microbiological contamination, the tissues are suitable for transplantation and are distributed on request.
There are in our country 5 cute banks3 for pancreatic islets, 6 for musculoskeletal tissues (bones, tendons, ligaments), 5 cardiovascular (valves and vessels) and 12 for corneas; the person responsible can be a doctor or a biologist, the samples are carried out by surgeons and healthcare personnel (technicians, biologists, inferiors) and the processing by biologists or technicians. It is very important to remember that all this is possible thanks to donorsthose people – or their loved ones – who give the consent for donation post-mortem.
Speaking of concrete data: what volumes of preserved leather are we currently talking about in your Bank at Niguarda?
To date we have 52,000 cm2 of skin already available for transplantation e 10,000 cm2 in quarantine (waiting for the results); then the supply is guaranteed by continuous donations and we also have a procedure to recover “initially bad” skin. If all this is not enough to treat patients, we can count on the other four Italian skin banks.
What is the process when a severely burned patient arrives?
It all starts with the sampling, which is performed on non-visible body parts of the cadaveric donor (back, upper and internal limbs) with the dermatomea sort of surgical razor that allows you to obtain flaps with an average size of 6×20 cm; in total from one donor they are obtained from 2000 to 5000 cm2.
Upon arrival, the burn victim comes stabilized from a resuscitation point of view, then theescarectomy – that is, a deep cleansing that removes the burned and no longer vital parts and leaves the healthy tissue exposed – and we proceed with the covering with donor skin (homograft): it is basically a “super-patch” which, among other effects, prepares the injured area to welcome the patient’s skin (autograft) – taken from healthy areas when there are any – and which is used for the final stages of healing.
Donor skin transplant (homograft) is always indicated and represents a life saver; this is because it allows you to cover even very large areas, reduces pain, avoids the loss of body fluids (especially proteins, essential for survival) and sends signals to the body to regulate inflammation and start healing.
After escarectomy, i skin flaps over the entire clean area: the edges are pricked with a particular machine, taking on the appearance of a gauze and are held together by staplesthen the whole thing is covered with bandages. After about 12 days or more, when the skin has “melted” and has exhausted its function, you can decide to apply it again or to switch to traditional dressings or – if recovery is in its final stages – the patient’s own skin is taken and transferred to the woundwhere it will take root and contribute to generate new skin.
How does new skin “respond” once healed?
Unfortunately, the new skin will not be identical to the original and the differences, both aesthetic and functionalwill depend on many factors. First of all the initial gravity (extension and depth). Thanks to the use of the skin, other types of dressings and techniques plastic surgery however, they can be obtained very good resultseven long after the burn has healed. Keep in mind that a healed/closed wound ends up changing later 2 years from the initial trauma.
What is the substantial difference compared to organ donation?
There are two main differences. The first concerns the transplant timing: Organs must be transplanted within approximately 6-12 hours from collectionalthough now it is possible – for some organs – to extend the times up to 48 hours thanks to ex-vivo perfusion machines. Fabrics, on the other hand, can be preserved for yearsso it is possible to make “stocks”. The second difference is that for fabrics Donor-recipient compatibility is not necessary therefore tissue from a donor – such as skin – can be used on multiple recipients.
While organ transplant is a permanent solution that requires compatibility to avoid rejection, donor skin acts as a life saver temporary. It doesn’t have to integrate forever, but only protect the patient immediately.
In the future, what will be the new frontier?
There are processes to “grow” skin in the laboratory, but these types of products are considered at a regulatory level drugs of the Advanced Therapies type. They are therefore not managed as simple tissues under the control of CNT (National Transplant Center), but as real drugs, therefore falling under the regulations ofAIFA (Italian Medicines Agency). In the past we were authorized to produce both epidermis and dermis, we are working to start again. We are working for go back to growing leather in the laboratory as in the past.
Other projects concern, for example, the obtaining of cell-free dermis (decellularized) and loaded with substances produced by cells capable of maximize healing and make the skin new the as similar as possible to the lost one.
