Irradiation as a Safety Procedure in Tissue Banking

Abstract

The Central Tissue Bank in Warsaw was established in 1963 and since then ionising radiation has been routinely applied to sterilise tissue grafts. Connective tissue grafts such as bone, cartilage, tendons, sclera, pericardium, skin, acellular dermis and amnion irradiated with a dose of 35 kGy in a (60)Co source and/or with an electron beam 10 MeV accelerator are prepared in our Tissue Bank and two other multi-tissue banks operating in Poland. Over 250,000 radiation-sterilised tissue grafts have been prepared and used in hospitals throughout Poland and no infectious disease transmission or other adverse post-transplantation reactions have been reported up to today. It should be kept in mind however, that high doses of ionising radiation can evoke numerous chemical and physical changes that may affect the biological quality of tissue allografts. Therefore, interdisciplinary research has been undertaken at the Central Tissue Bank in Warsaw to establish the origin and stability of free radicals and other paramagnetic entities induced by irradiation in bone. The effects of various preservation procedures (e.g. lyophilisation, deep-freezing) and irradiation conditions (doses, temperature of irradiation) on the osteoinductive potential and mechanical properties of bone and on the degradation of collagen, a major constituent of all connective tissue grafts, have been also studied. The results of these studies indicate that radiation-induced changes can be diminished by modification of tissue preservation methods and that, to some extent, it is possible to reduce undesired radiation-induced damage to the tissue grafts.

Freeze‐dried human serum albumin improves the adherence and proliferation of mesenchymal stem cells on mineralized human bone allografts

“…The desinfection of donor bone kills not just the potentially contagious microorganisms but destroys most of the biologically active proteins, such as cell-adhesive proteins. [13][14][15] Therefore, such a way prepared freeze-dried bone allograft consists of inorganic components of the bone in majority (mineralized bone) and just a few organic materials. Cell-adhesive proteins play a crucial role both in the attachment and proliferation of cells on the surface of scaffolds.…”

“…[11][12][13] For the patient safety the allografts are supposed to be subjected to desinfection so as to avoid the transfer of contagious agents from the donor to the recipient. 14,15 Freeze-drying technique allows the profound desinfection of allogeneic bone grafts with chemicals, like acids and ethylene-oxide because these agents are eliminating from the allograft during the freeze-drying. As the disadvantageous effect of such a desinfection the osteogenic cells are killed on the allograft and most of the osteoinductive proteins become denatured, which impairs the biological value of the allograft.…”

Improved Tendon Radioprotection by Combined Cross-linking and Free Radical Scavenging

“…Effective sterilization must be successful against a wide variety of pathogens, exhibit high penetrability through tissue structure, and preserve native properties and functionality [1]. Ionizing irradiation is capable of meeting the first two requirements [4,12,34,35], but at the high doses required to inactivate resistant pathogens, tissue mechanical properties are known to deteriorate [1,17,36]. We hypothesized that a combined cross-linking and free radical scavenging treatment would produce an improved protective effect beyond single treatments previously examined [39].…”

Irradiation Does Not Modify Mechanical Properties of Cancellous Bone Under Compression

“…Gamma radiation sterilization (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) is commonly used to reduce the risk of disease transmission through bone allograft [15]. In cortical bone, gamma radiation at typical sterilization doses causes reductions in ultimate strength [20], bending strength [13], work to fracture [2,20], fatigue life [1], and resistance to fatigue crack growth [26].…”