Increasing Donor Body Weight to Prevent Small-for-Size Syndrome in Living Donor Liver Transplantation

The Hollywood actress Renee Zellweger famously put on 20 lb in weight to make her appearance more suitable for the title role in the successful film Bridget Jones’s Diary [1]. In this issue of the World Journal of Surgery, Liu and colleagues from Taipei have advocated that in certain cases, potential living liver donors could be asked to gain weight, to increase the size of the future donor liver [2]. There is a clear association between graft recipient weight ratio and risk of development of small-for-size syndrome in living donor liver transplantation. Thus increasing the future liver may be a mechanism of reducing risk to the recipient. Normally, weight gain is seen in the context of potential health disadvantage, and so this article represents a somewhat controversial but very novel approach to the problem of a potentially small liver for donation. One of the fundamental questions in this approach is whether the whole body weight gain is detrimental not only to the health of the donor but also to the quality of the liver. Current evidence seems to suggest that an excessive and long-term increase in body weight is associated with an increase in the fat content of the liver and a higher risk of developing metabolic syndrome [3]. This may lead to fatty liver diseases (NAFLD or NASH) that are a fast rising indication for transplantation. Liu and colleagues challenge this concept and demonstrate that a short and well-controlled period of body weight gain does not translate into a deterioration of the liver quality. Instead, it leads to an increase in the overall liver volume that allows for a safe donation and transplantation. It is conceivable that the changes seen by Liu et al. are partially due to the high protein and carbohydrate diet, a strict control of weight gain, and the lack of pre-existent fatty changes in the liver. This short-lived weight gain seems to be rapidly reversible. Following cessation of the weight gain in the volunteers or completion of the donation process, a return to the initial body weight parameters appears to have taken place in all patients, without any immediate ill effects. Although this answers the question of immediate risks, it remains to be seen whether this rapid fluctuation in weight has any longterm impact on the donor’s health, increasing the risk of cardiovascular disease or the susceptibility to develop a metabolic syndrome later in life. This controversial approach has paid off and recipients received an appropriately sized graft that prevented the development of small for size syndrome. Our understanding of the pathophysiology of small-for-size syndrome and its clinical implications has made tremendous progress in recent years [4]. Several strategies for improving the outcome are now well established. One could argue that a less controversial approach, concentrating on recipient measures with inflow modulation, rather than donor weight modulation, is likely to be more successful and would be ethically more acceptable. Nevertheless, in a system where living liver donation is the only realistic option, and when there are no other potential donors for a given recipient, such an approach will save the life of patients who would otherwise have no alternative. Clearly, this is not a ‘‘one for all’’ measure, and the authors point out that only a few selected (and determined, G. C. Oniscu Scottish Liver Transplant Unit, Royal Infirmary of Edinburgh, Edinburgh, UK