The preservation and storage of Umbilical Cord stem cells

Ethical aspects relating to the preservation and storage of cord blood are linked not so much to the nature of the cord cells as to technical questions pertaining to the collection and preservation of these cells, aspects which need to be considered in the light of the principle of the proportionality of medical treatments. In the present state of our knowledge, the procedures for the collection, preservation and storage of cord blood cells do not give rise to particular difficulties and the expectation that, in future, these sources of stem cells may play an increasingly significant role in the treatment of diseases, especially of those of a degenerative nature, is more than reasonable. Therefore, the fundamental question is whether the present engagement of resources for the collection and the preservation of cord blood is proportionate to the foreseen benefits, at present and / or in the future. An adequate evaluation of the proportionality of using such resources requires that first of all that we possess an adequate knowledge of the procedures involved and of their costs; to be evaluated in terms of the use of resources, both economic and human.

It has been seen that it is possible to preserve the cells of umbilical cord blood through freezing at – 196˚C; after thawing it is also possible to transfer such cells into a host organism without their losing their property of being able to repopulate. Such circumstances allow the long term storage of umbilical cord blood in so-called “cord blood banks”. The prospect of this has attracted public attention, especially in relation to the increasing diffusion of information about the multiple properties of stem cells derived from the umbilical cord. Such interest could be destined to increase further after the announcement of the possibility of deriving induced pluripotent stem cells (IPSs, induced pluripotent stem cells) from cord stem cells. The banks for preserving cord blood are true and proper “banks”, where the units of cord blood are stored. After being collected in the delivery room, the unit of cord blood is sent to the bank, where it is subjected to a series of specific tests to verify its suitability for preservation and to define its immunological characteristics, for the purpose of the analysis of compatibility between donor and recipient.

01. History of the establishment of Umbilical Cord Blood banks

The first bank for the preservation of cord blood was created in New York city in 1991, through the initiative of P. Rubinstein, soon after the first successful transplant of umbilical cord blood by E. Gluckman in 1989. In 1993 the first two transplants of cord blood coming from donors without links of kinship with the recipient were effected, using these banks, while in 1996 the results were published of the first important series of these transplants. These result have demonstrated that, to facilitate transplants of umbilical cord blood, it might be advisable to have available throughout the world large quantities of cord blood units, with good characteristics and of high quality. From that time onwards many researchers began to develop protocols for the collection, storage and release of cord blood units for transplants to potential recipients, who might or might not have links of kinship to the donors of these blood units.

The affirmation, from 1992 onwards, that GVHD (graft versus host disease) was less serious and less frequent in transplants of umbilical cord blood, compared with transplants with haematopoetic stem cells from bone marrow, has stimulated both the clinical use of cord blood and, as a consequence, the need to establish public banks of cord blood, following the model of the bank established by P. Rubinstein. Between 1992 and 1993 different public banks opened up also in Europe (Paris, Milan, Düsseldorf, Liège and the United Kingdom). The possibility, reported in 1994, of conducting a successful transplant of umbilical cord blood from a donor extraneous to the recipient and with only partial HLA compatibility has further stimulated the creation of such banks.

The multiplication of cord blood banks throughout the world has led to the establishment of different networks between banks, both at the national and international level, to foster the exchange of information between the various centres. The largest international register regarding bone marrow and cord blood is the Bone Marrow Donors Worldwide (BMDW), which started in 1998, and has its offices in Leiden (Holland). It results from a voluntary collaboration between the registers of donors of bone marrow and the registers from banks of cord blood. Its scope is to furnish centralised and anonymous information relating to HLA phenotypes and other pertinent data relative to bone marrow donors and to units of cord blood.

At present the BMDW constitutes the largest database in the world, including 14 million donors of stem cells and cord blood units and gathering together the data of 44 cord blood banks in 26 countries. In 1994 the European cord blood banking group was established to manage the collection of cord blood at a European level, to standardise procedures for collection and for preservation of blood units, to set up ethical guidelines for the use of these units, and to facilitate international cooperation in this sector, through different institutions. Subsequently, there have emerged numerous other international networks, for a description of which people should refer to the relevant paragraph in the section "Normative Aspects" of the present document.

02. Types of cord blood banks

There are three types of cord blood bank, according to the type of donation and use of the cords:

01. Unrelated, allogeneic cord blood banks, between persons who are HLA identical or not identical. Banks of allogeneic umbilical cord blood, not related by kinship, are in general public banks, established by public centres for transplants. The principle which regulates the contribution of units of cord blood in these banks is that of the altruistic gift of cord blood, comparable to the donation of blood to the transfusion services or to the donation of organs in the context of transplants.

The donation is anonymous, but it should be indicated on the health card of the child and it should be possible to trace the donor. He could thus, et least theoretically, have access to his own placentary blood, if, at a specific point in his life, he needed a boost of haematopoietic stem cells. The cords stocked in these banks are enlisted in a national and in an international register, along with a note of their characteristics (concentration in cells) and their HLA type. The collection, treatment, preservation of the cords and their export follow criteria fixed at the international level, which guarantees the quality of the units and their reliability. The quality of the units to be preserved has priority over their quantity. The majority of public cord blood banks in the world are accredited or are in the process of gaining accreditation with NETCORD and follow the Netcord-FACT standards.

02. Related family cord blood banks (by kinship), within the family setting, between brothers and sisters HLA identical. The collection of cord blood from relatives, in a family, can be a "directed deposit’, where the cord blood is collected from a brother of the patient at his birth, with a view to treating this patient. The problem encountered with this type of collection is that, too often, (70% of cases) the cord blood collected does not have a perfect HLA correspondence with the relative who is a recipient candidate and that it is improbable that these units will be used one day in the future for the patient for whom they were destined.

03. Autologous cord blood banks. Banks of autologous cord blood are, in general, private banks, with the aim of making a profit, which, on the basis of a payment, preserve blood from the umbilical cords of children born in a specific family with a view to the eventual use of this blood within the family (among relatives) or for the child himself (autologous).