Great progress has been made in the field of liver transplantation over the past two decades. This progress, however, also brings up the next set of challenges: First, organ shortage remains a major limitation, and accounts for a large proportion of wait list mortality. While living donation has successfully increased the total number of liver transplants done in Asian countries, the total number of such transplants has been stagnant in the western hemisphere. As such, there has been a significant effort over the past decade to increase the existing deceased donor pool. This effort has resulted in a greater use of liver allografts following donation after cardiac death (DCD) along with marginal and extended criteria donors. Improved understanding of the pathophysiology of liver allografts procured after circulatory arrest has not only resulted in better selection and management of DCD donors, but has also helped in the development of mechanical perfusion strategies. Early outcomes demonstrating the clinical applicability of both hypothermic and normothermic perfusion and its potential to impact patient survival and allograft function have generated much interest. Second, long-term outcomes of liver transplant recipients have not improved significantly, as recipients continue to succumb to complications of long-term immunosuppression, such as infection, malignancy and renal failure. Furthermore, recent evidence suggests that chronic immune-mediated injury to the liver may also impact graft function.

Complications of portal hypertension, including ascites, gastrointestinal bleeding, hepatic hydrothorax, and hepatic encephalopathy, are associated with significant morbidity and mortality. Despite few high-quality randomized controlled trials to guide therapeutic decisions, transjugular intrahepatic portosystemic shunt (TIPS) creation a Authors share co-first authorship. b Authors share co-senior authorship.

Donation after cardiac death (DCD) and acute kidney injury (AKI) donors have historically been considered independent risk factors for delayed graft function (DGF), allograft failure, and inferior outcomes. With growing experience, updated analyses have shown good outcomes. There continues to be limited data, however, on outcomes specific to DCD donors who have AKI. Primary outcomes for this study were post–kidney transplant patient and allograft survival comparing two donor groups: DCD AKIN stage 2‐3 and DBD AKIN stage 2‐3. In comparing these groups, there were no short‐ or long‐term differences in patient (hazard ratio [HR] 1.07, 95% confidence interval [CI] 0.54‐1.93, P = .83) or allograft survival (HR 1.47, 95% CI 0.64‐2.97, P = .32). In multivariate models, the DCD/DBD status had no significant impact on the estimated GFR (eGFR) at 1 (P = .38), 2 (P = .60), and 3 years (P = .52). DGF (57.9% vs 67.9%, P = .09), rejection (12.1% vs 13.9%, P = .12), and progression of interstitial fibrosis/tubular atrophy (IFTA) on protocol biopsy (P = .16) were similar between the two groups. With careful selection, good outcomes can be achieved utilizing severe AKI DCD kidneys. Historic concerns regarding primary nonfunction, DGF resulting in interstitial fibrosis and rejection, and inferior outcomes were not observed. Given the ongoing organ shortage, increased effort should be undertaken to further utilize these donors.

Introduction Several clinical trials are currently evaluating stem cell therapy for patients with critical limb ischemia that have no other surgical or endovascular options for revascularization. However, these trials are conducted with different protocols, including use of different stem cell populations and different injection protocols, providing little means to compare trials and guide therapy. Accordingly, we developed a murine model of severe ischemia to allow methodical testing of relevant clinical parameters. Methods High femoral artery ligation and total excision of the superficial femoral artery (SFA) was performed on C57BL/6 mice. MNC were isolated from the bone marrow of donor mice, characterized using FACS, and injected (5×105−2×106) into the semimembranosus (proximal) or gastrocnemius (distal) muscle. Vascular and functional outcomes were measured using invasive Doppler, laser Doppler perfusion imaging, and the Tarlov and ischemia scores. Histological analysis included quantification of muscle fiber area and number as well as capillary density. Results Blood flow and functional outcomes were improved in MNC-treated mice as compared to controls over 28 days (Flow: P < .0001; Tarlov: P = .0004; ischemia score: P = .0002). MNC-treated mice also showed greater gastrocnemius fiber area (P = .0053) and increased capillary density (P = .0004). Dose-response analysis showed increased angiogenesis and gastrocnemius fiber area but no changes in macroscopic vascular flow or functional scores. Mice injected proximally to the ischemic area had overall similar functional outcomes to mice injected more distally, but increased muscle flow, capillary density, and gastrocnemius fiber area (P < .05). Conclusions High femoral ligation with complete excision of the SFA is a reliable model of severe hind limb ischemia in C57BL/6 mice that shows a response to MNC-treatment for both functional and vascular outcomes. A dose response to MNC injection appears to be present, at least microscopically, suggesting that an optimal cell number for stem cell therapy exists and that preclinical testing needs to be performed to optimally guide human trials. Injection of MNC proximal to the site of ischemia may provide some different outcomes compared to distal injection and warrants additional study.