DEVELOPING AN EX VIVO LIMB PERFUSION PROTOCOL

Abstract

This thesis attempts to identify whether experimentally, machine perfusion technology can be safely adopted for the preservation of composite tissues. This is in an attempt to optimise outcomes in both replantation and transplantation. Any intervention that supersedes the current gold standard of cold static storage, whereby grafts incur cell death and injury (from an absent blood supply) remains a crucial target. The importance of this research question is highlighted in Chapter 1 which gives a background to the clinical problem, namely that limb preservation strategies have not evolved for over 75 years. As such, the assimilation of an ex vivo machine perfusion system and the development of a protocol that serves to preserve composite limbs is outlined in Chapter 3. A wealth of clinical evidence supports the use of this technology for solid organ evaluation and preservation prior to transplantation. However, protocols invariably differ and it is apparent that tissues have specific physiological requirements. There are well-studied parameters that are known to influence solid organ preservation throughout perfusion, which have yet to be extensively interrogated for composite tissues. A systematic approach to evaluating key parameters is discussed in Chapter 4. What is more, in a closed system biochemical and acid-base imbalance are inevitable and a novel experiment described in Chapter 5 evaluates whether the addition of a kidney onto the circuit maintains better physiological homeostasis. Chapter 6 aims to address whether in theory, immunological rejection can be minimised via the removal of donor leukocytes and inflammatory mileu. Firstly, whether vascular flush out of the donor limb can remove such alloantigens and how whether this can be further influenced by machine perfusion. The combination of limb preservation and therapeutic manipulation (for transplantation) to improve long-term graft outcomes may provide a step-wise change in the future management of amputated parts, which has met little progress despite significant advancement in logistical planning and the surgical approach.

Date of Award	1 Aug 2020
Original language	English
Awarding Institution	The University of Manchester
Supervisor	James Fildes (Supervisor) & Jason Wong (Supervisor)