**1. Introduction**

Since Kelly and colleagues performed the first whole pancreas transplant in 1966, significant advancements in pancreas transplantation have been made. [1] There was a gap following the first series of whole pancreas transplants due to poor graft outcomes with significant impact from poor organ preservation of the pancreas playing a major role. It took almost 20 years for the development of newer surgical techniques including use of newly developed perfusion solutions, segmental grafts, advances in ductal drainage including bladder drainage, and effective immunosuppression regimens such that whole organ transplantation burgeoned, with great advances made by Sutherland and colleagues at the University of Minnesota [2]. However, it was not until much later following many years of experimental research that pancreata for islet cell isolation and transplantation became a reality. Over the past two decades in particular a great deal of effort has underpinned making islet cell transplantation a viable therapy for a broader range of patients with type 1 diabetes (T1D). Clinical results have progressively improved, now demonstrating outcomes on par with other organ transplants, specifically in terms of insulin independence, and graft and patient survival [3]. We are now at the point where islet cell transplantation, in the form of allotransplantation, like its forebear whole organ transplantation, has become widely accepted as a clinical therapy for patients affected by T1D.

pharmacological treatment of recipients such as newer focused monoclonal immunosup-

Pancreas Retrieval for Whole Organ and Islet Cell Transplantation

http://dx.doi.org/10.5772/intechopen.75151

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This chapter focuses on the optimal process for deceased donor pancreas retrieval and its role in maximizing graft function and survival. However, with a great number of processes to outline, only the major ones will be covered in this chapter. In particular, we will emphasize major improvements in donor selection, surgical retrieval techniques, pancreas retrieval in the context of multi-organ donors, back-table preparation of the pancreas, perfusion fluid types, and future perspectives including the utilization of technologies such as machine perfusion and persufflation. These factors will be discussed in the context of improved outcomes to the engraftment, function and survival of the transplants. It is also acknowledged that there remains the ongoing need for further improvements to both whole organ and islet cell transplantation, however both techniques clearly offer safe and achievable therapeutic options for

The original retrieval processes of the modern era were initially developed for and used in kidney only retrieval surgery. As per **Figure 1** the procedure first introduced in 1963 utilized cold lactated Ringer's or low-molecular-weight dextran solutions infused directly into the renal artery of the retrieved kidneys, performed only after their removal from the donor [11]. These were the beginnings of modern donor retrieval but they were less than ideal techniques due to the time taken to perfuse the organs, and therefore a number of more active and by far more effective methods of perfusion and cooling of organs were subsequently developed in order to minimize ischemic insult and subsequent damage to organs. These techniques were based upon the concepts from cardiothoracic surgery, involving active patient cooling during procedures to prevent ischemic damage [12, 13]. The transplant fraternity quickly adopted these intravascular perfusion-related cooling techniques, which were standardly utilized as a first step in the preservation of all whole-organ grafts. The currently accepted modern cadaveric donor procedure is performed using some basal form of the *ex situ* techniques developed and performed in the mid to late 60's by Starzl and colleagues [14] for not only kidneys but also incorporating the pancreas and liver. Further refinements saw the perfusion and addition of heparin to the perfusate solutions and also the donor. Ensuring removal of blood by *ex situ* perfusion as described by Belzer et al. [15] resulted in improved but only satisfactory kidney preservation of several days. However, this technique was eventually abandoned in most kidney transplant centers when it was learned that the quality of 2-day preservation was no

The underpinning method of *iced slush* for shipping was based around experimental work on kidneys [17]. This research and practice focused on perfusion fluids of differing intracellular and extracellular fluids consisting of electrolytes with varying osmotic and oncotic effects that were infused into the allograft before placing it in a cold storage container. Collins

pressive strategies that better control graft rejection [9].

the ever-expanding number of patients suffering from T1D [10].

better than with the simpler *"iced slush"* methods [16].

**2. Historical timeline**

Now more than five decades on and with many organ donor operations having been performed since the advent of organ donor procedures as we know them, we have refined and perfected the organ donor process since the first organ retrieval of a brain dead donor in 1963 [4] and the subsequent adoption of the "Acceptance of Brain Death for Organ Donation" issued by the Ad Hoc Committee of the Harvard Medical School [5]. We have seen an increasing emergence of specialized organ retrieval teams with focus on the overwhelming need to improve organ donor rates for the ever increasing recipient patient population [6]. Always a dedicated surgical pursuit, research into organ donation and the surgical retrieval process for the pancreas and most other organs has often been overlooked in favor of recipientrelated research into the prevention of rejection, and improving immunosuppression and tissue matching. This is particularly problematic when it comes to whole pancreas and islet transplantation as the pancreas is a less retrieval tolerant organ than other solid organs, and requires extra attention both during and after retrieval to ensure that the organ's valuable islets, which are especially susceptible to hypoxia and the ischemic insult, are effectively preserved [7, 8].

In this chapter we provide a general overview of Pancreas Retrieval for both Whole Organ and Islet Cell Transplantation, but it should be noted that there are clear overlaps in this process for both whole organ and cellular transplantation. As such the way the processes are performed can be utilized for retrieval for either type of subsequent transplant. Overall, we have seen significant improvements to pancreas transplantation results, in particular in the islet cell arena, due to the significant research undertaken to improve graft outcomes by improving donor selection and organ procurement and preservation [9]. On the recipient side we have also further improved outcomes with changes to the transplant and to the pharmacological treatment of recipients such as newer focused monoclonal immunosuppressive strategies that better control graft rejection [9].

This chapter focuses on the optimal process for deceased donor pancreas retrieval and its role in maximizing graft function and survival. However, with a great number of processes to outline, only the major ones will be covered in this chapter. In particular, we will emphasize major improvements in donor selection, surgical retrieval techniques, pancreas retrieval in the context of multi-organ donors, back-table preparation of the pancreas, perfusion fluid types, and future perspectives including the utilization of technologies such as machine perfusion and persufflation. These factors will be discussed in the context of improved outcomes to the engraftment, function and survival of the transplants. It is also acknowledged that there remains the ongoing need for further improvements to both whole organ and islet cell transplantation, however both techniques clearly offer safe and achievable therapeutic options for the ever-expanding number of patients suffering from T1D [10].
