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.

With the global prevalence of type 2 diabetes mellitus steeply rising, instances of chronic, hard-healing, or non-healing diabetic wounds and ulcers are predicted to increase. The growing understanding of healing and regenerative mechanisms has elucidated critical regulators of this process, including key cellular and humoral components. Despite this, the management and successful treatment of diabetic wounds represents a significant therapeutic challenge. To this end, the development of novel therapies and biological dressings has gained increased interest. Here we review key differences between normal and chronic non-healing diabetic wounds, and elaborate on recent advances in wound healing treatments with a particular focus on biological dressings and their effect on key wound healing pathways.

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Chronic wounds are a significant socio-economic problem, thus, the improvement of the effectiveness of their treatment is an important objective for public health strategies. The predominant stage of the chronic wound is the inflammatory reaction which is associated with the damage of tissues, possibly due to the excessive secretion and activation of matrix metalloproteinases (MMPs). Several reports have suggested that amnion dressing inhibits tissue destruction and accelerates wound healing. Our recent study revealed that sterilized amnion stimulates keratinocyte proliferation in vitro, while the present study focused on the clinical application of radiation-sterilized amnion in chronic venous leg ulcers and aimed to explain the possible mechanism of its in vivo action. The study involved 25 individuals suffering from venous leg ulceration with a surface area of 10-100 cm2 and a healing rate below 10% per week, as verified during a 2-week screening period. The effectiveness of the amnion dressing was estimated following 4 weeks of treatment. The wound assessment, based on a modified Bates-Jensen Questionnaire, revealed a good and satisfactory response to the treatment in 23 of the 25 patients. The measurement of MMP-2 and MMP-9 activities in wound exudates revealed a decrease in activity in response to amnion application. This effect resulted from the presence of the potent MMP inhibitors, tissue inhibitor of metalloproteinases-1 (TIMP-1), type-1 plasminogen activator inhibitor (PAI-1) and thrombospondin-1 (TSP-1) in the amnion dressings, as shown by real-time fluorescence zymography and protein microarrays. Thus, unlike modern synthetic dressing materials, radiation-sterilized amnion dressings may have a multidirectional beneficial effect on chronic wounds.