Douglas Quan

Pattern of liver, kidney, heart, and intestine allograft rejection in different mouse strain combinations.

With advances in microsurgery and molecular biology, the mouse model for organ transplantation has become increasingly popular. However, knowledge about these models is limited, as only a small number of centers have experience with murine models. In this study, we compared the rejection pattern after liver, kidney, heart, and small bowel transplantation in the three different mouse strain combinations: (1) C57BL/6 (H2b)-->BALB/c (H2d), (2) BALB/c (H2d)-->CBA (H2k), and (3) C57BL/6-->C3H/HeN (H2k). Our study demonstrated that mouse allograft survival varies depending on the organ graft and on the donor-recipient strain combinations. The majority of liver allografts were spontaneously accepted despite complete MHC disparity. A mixed pattern of acute rejection and acceptance occurred in kidney recipients depending on the donor-recipient strain combination. All the heart grafts developed rejection and all the intestinal grafts were rapidly rejected with no spontaneous acceptance. The criteria for rejection, the potential applications, and the limitations of each model are discussed. The models described in this article provide a number of useful choices for organ transplantation research.

Recurrent hepatocellular carcinoma after transplantation: Use of a pathological score on explanted livers to predict recurrence

Milan and University of California at San Francisco (UCSF) criteria are used to select patients with hepatocellular carcinoma (HCC) for liver transplantation (LT). Recurrent HCC is a significant cause of death. There is no widely accepted pathological assessment strategy to predict recurrent HCC after transplantation. This study compares the pathology of patients meeting Milan and UCSF criteria and develops a pathological score and nomogram to assess the risk of recurrent HCC after transplantation. All explanted livers with HCC from our center over the 18‐yr period 1985 to 2003 were assessed for multiple pathological features and relevant clinical data were recorded; multivariate analysis was performed to determine features associated with recurrent HCC. Using pathological variables that independently predicted recurrent HCC, a pathological score and nomogram were developed to determine the probability of recurrent HCC. Of 75 cases analyzed, 50 (67%) met Milan criteria, 9 (12%) met only UCSF criteria and 16 (21%) met neither criteria based on explant pathology. There were 20 cases of recurrent HCC and the mean follow‐up was 8 yr. Recurrent HCC was more common (67 vs. 12%; P < 0.001) and survival was lower (15 vs. 83% at 5 yr; 15 vs. 55% at 8 yr; P < 0.001) with those who met only UCSF criteria, compared to those who met Milan criteria. Cryptogenic cirrhosis (25 vs. 5%; P = 0.015), preoperative AFP >1,000 ng/mL (20 vs. 0%; P < 0.001) and postoperative OKT3 use (40 vs. 15%; P = 0.017) were more common among patients with recurrent HCC. While microvascular invasion was the strongest pathological predictor of recurrent HCC, tumor size ≥3 cm (P = 0.004; odds ratio [OR] = 7.42), nuclear grade (P = 0.044; OR = 3.25), microsatellitosis (P = 0.020; OR = 4.82), and giant/bizarre cells (P = 0.028; OR = 4.78) also predicted recurrent HCC independently from vascular invasion. The score and nomogram stratified the risk of recurrent HCC into 3 tiers: low (<5%), intermediate (40–65%), and high (>95%). In conclusion, compared to patients meeting Milan criteria, patients who meet only UCSF criteria have a worse survival and an increased rate of recurrent HCC with long‐term follow‐up, as well as more frequent occurrence of adverse histopathological features, such as microvascular invasion. Application of a pathological score and nomogram could help identify patients at increased risk for tumor recurrence, who may benefit from increased surveillance or adjuvant therapy. Liver Transpl, 2007.

Effect of PET Before Liver Resection on Surgical Management for Colorectal Adenocarcinoma Metastases: A Randomized Clinical Trial

IMPORTANCE Patients with colorectal cancer with liver metastases undergo hepatic resection with curative intent. Positron emission tomography combined with computed tomography (PET-CT) could help avoid noncurative surgery by identifying patients with occult metastases. OBJECTIVES To determine the effect of preoperative PET-CT vs no PET-CT (control) on the surgical management of patients with resectable metastases and to investigate the effect of PET-CT on survival and the association between the standardized uptake value (ratio of tissue radioactivity to injected radioactivity adjusted by weight) and survival. DESIGN, SETTING, AND PARTICIPANTS A randomized trial of patients older than 18 years with colorectal cancer treated by surgery, with resectable metastases based on CT scans of the chest, abdomen, and pelvis within the previous 30 days, and with a clear colonoscopy within the previous 18 months was conducted between 2005 and 2013, involving 21 surgeons at 9 hospitals in Ontario, Canada, with PET-CT scanners at 5 academic institutions. INTERVENTIONS Patients were randomized using a 2 to 1 ratio to PET-CT or control. MAIN OUTCOMES AND MEASURES The primary outcome was a change in surgical management defined as canceled hepatic surgery, more extensive hepatic surgery, or additional organ surgery based on the PET-CT. Survival was a secondary outcome. RESULTS Of the 263 patients who underwent PET-CT, 21 had a change in surgical management (8.0%; 95% CI, 5.0%-11.9%). Specifically, 7 patients (2.7%) did not undergo laparotomy, 4 (1.5%) had more extensive hepatic surgery, 9 (3.4%) had additional organ surgery (8 of whom had hepatic resection), and the abdominal cavity was opened in 1 patient but hepatic surgery was not performed and the cavity was closed. Liver resection was performed in 91% of patients in the PET-CT group and 92% of the control group. After a median follow-up of 36 months, the estimated mortality rate was 11.13 (95% CI, 8.95-13.68) events/1000 person-months for the PET-CT group and 12.71 (95% CI, 9.40-16.80) events/1000 person-months for the control group. Survival did not differ between the 2 groups (hazard ratio, 0.86 [95% CI, 0.60-1.21]; P = .38). The standardized uptake value was associated with survival (hazard ratio, 1.11 [90% CI, 1.07-1.15] per unit increase; P < .001). The C statistic for the model including the standardized uptake value was 0.62 (95% CI, 0.56-0.68) and without it was 0.50 (95% CI, 0.44-0.56). The difference in C statistics is 0.12 (95% CI, 0.04-0.21). The low C statistic suggests that the standard uptake value is not a strong predictor of overall survival. CONCLUSIONS AND RELEVANCE Among patients with potentially resectable hepatic metastases of colorectal adenocarcinoma, the use of PET-CT compared with CT alone did not result in frequent change in surgical management. These findings raise questions about the value of PET-CT scans in this setting. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00265356.

The role of liver resection for colorectal cancer metastases in an era of multimodality treatment: A systematic review

BACKGROUND To determine the role of liver resection in patients with liver and extrahepatic colorectal cancer metastases and the role of chemotherapy in patients in conjunction with liver resection. METHODS MEDLINE and EMBASE databases were searched for articles published between 1995 and 2010, along with hand searching. RESULTS A total of 4875 articles were identified, and 83 were retained for inclusion. Meta-analysis was not performed because of heterogeneity and poor quality of the evidence. Outcomes in patients who had liver and lung metastases, liver and portal node metastases, and liver and other extrahepatic disease were reported in 14, 10, and 14 studies, respectively. The role of perioperative chemotherapy was assessed in 30 studies, including 1 randomized controlled trial and 1 pooled analysis. Ten studies assessed the role of chemotherapy in patients with initially unresectable disease, and 5 studies assessed the need for operation after a radiologic complete response. CONCLUSION The review suggests that: (1) select patients with pulmonary and hepatic CRC metastases may benefit from resection; (2) perioperative chemotherapy may improve outcome in patients undergoing a liver resection; (3) patients whose CRC liver metastases are initially unresectable may benefit from chemotherapy to identify a subgroup who may benefit later from resection; (4) after radiographic complete response (RCR), lesions should be resected if possible.

ALTERED GENE EXPRESSION OF CYTOKINE, ICAM-1, AND CLASS II MOLECULES PRECEDES MOUSE INTESTINAL ALLOGRAFT REJECTION

Rapid and severe rejection remains a major obstacle to successful clinical intestinal transplantation (IT). The aggressive nature of rejection in IT has been attributed to the increased massive immune stimulus provided by large numbers of resident lymphocytes, antigen presentation capacity of enterocytes, and graft damage mediated by luminal microflora. Early small bowel expression of proinflammatory cytokines, MHC class II, and adhesion molecules may also promote IT rejection, but the lack of a mouse model has hampered extensive studies of gene expression in IT. Using a recently developed surgical model, we examined the temporal pattern of gene expression in CB6F1 (H-2b/d) vascularized, heterotopic intestinal allografts transplanted into BALB/c (H-2d) mice. Although histological evidence of rejection was not present until day 7 in allografts, Northern blot analysis demonstrated increases in TNF alpha gene transcripts as early as day 3, followed by the expression of IL-1 beta, intercellular adhesion molecule-1, and MHC class II by day 5. Using reverse-transcriptase polymerase chain reaction, IFN-gamma was detected in allografts by day 3 and persisted to day 10. In contrast, IL-2, IL-4, IL-5, and IL-6 mRNA transcripts peaked by day 5 and then decreased, suggesting that both Th1 and Th2 subsets are involved in the rejection of unmodified small bowel allografts. The early and progressive expression of TNF alpha and IL-1 beta as well as IFN-gamma, intercellular adhesion molecule-1, and MHC class II in IT rejection may contribute to the difficulty in controlling IT rejection with present immunosuppression.

Long-term outcomes of emergency liver transplantation for acute liver failure.

Acute liver failure continues to be associated with a high mortality rate, and emergency liver transplantation is often the only life‐saving treatment. The short‐term outcomes are decidedly worse in comparison with those for nonurgent cases, whereas the long‐term results have not been reported as extensively. We report our centers experience with urgent liver transplantation, long‐term survival, and major complications. From 1994 to 2007, 60 patients had emergency liver transplantation for acute liver failure. The waiting list mortality rate was 6%. The mean waiting time was 2.7 days. Post‐transplantation, the perioperative mortality rate was 15%, and complications included neurological problems (13%), biliary problems (10%), and hepatic artery thrombosis (5%). The 5‐ and 10‐year patient survival rates were 76% and 69%, respectively, and the graft survival rates were 65% and 59%. Recipients of blood group–incompatible grafts had an 83% retransplantation rate. Univariate analysis by Cox regression analysis found that cerebral edema and extended criteria donor grafts were associated with worse long‐term survival. Severe cerebral edema on a computed tomography scan pre‐transplant was associated with either early mortality or permanent neurological deficits. The keys to long‐term success and continued progress in urgent liver transplantation are the use of good‐quality whole grafts and a short waiting list time, both of which depend on access to a sufficient pool of organ donors. Severe preoperative cerebral edema should be a relative contraindication to transplantation. Liver Transpl 15:1696–1702, 2009.

Prospective Evaluation of the Role of Quantitative Doppler Ultrasound Surveillance in Liver Transplantation

Doppler ultrasound (DUS) is able to measure parameters of blood flow within vessels of transplanted organs, and vascular complications are associated with abnormal values. We analyzed the findings of 51 consecutive patients who underwent DUS on 2 occasions in the first postoperative week following liver transplantation for cirrhosis to determine the range of values in patients following liver transplantation. Three patients developed early vascular thromboses that were detected by the absence of a Doppler signal. In patients making an uneventful recovery, the arterial velocity tended to increase and the resistive index (RI) to decrease during the first postoperative week. All recipients were shown to have high‐velocity segments within the hepatic artery, without an increase in flow resistance. Assessment of the portal vein revealed narrowing at the anastomosis, associated with a segmental doubling of flow velocity, and the mean portal venous flow decreased by approximately 20% in the first postoperative week. In conclusion, a wide range of abnormalities occurs in the vessels of liver transplant recipients, which were not associated with the development of vascular complications or affect patient management. (Liver Transpl 2004;10:1183–1188.)

Infarct-like necrosis: a distinct form of necrosis seen in colorectal carcinoma liver metastases treated with perioperative chemotherapy.

The response of colorectal adenocarcinoma liver metastases to perioperative chemotherapy can be assessed histologically in partial hepatectomy specimens. Necrosis in this scenario may represent a lack of treatment effect or a therapeutic response to chemotherapy. This study sought to validate the histologic classification of necrosis into 2 types: usual necrosis (UN) representing an absence of treatment effect, and infarct-like necrosis (ILN) representing a therapeutic response to chemotherapy. Tumor regression grade (TRG) is a previously described prognosticating method that estimates tumor replacement by fibrosis. We incorporated ILN into a modified TRG (mTRG) and compared its performance as a prognostic factor against TRG. A retrospective clinical and histologic review was undertaken of all partial hepatectomies performed for colorectal liver metastases at our center between 2004 and 2010. Clinicopathologic features were compared between the 2 types of necrosis, including survival stratified by TRG and mTRG. A total of 109 cases were reviewed, with 46 patients receiving perioperative chemotherapy. ILN was identified in 12 cases, and all of these cases were associated with perioperative chemotherapy. ILN was significantly associated with perioperative treatment with bevacizumab. In patients receiving perioperative chemotherapy, those with ILN had superior disease-free survival compared with those with UN (P=0.047). mTRG1 to 2 scores were associated with significantly better survival compared with mTRG3 to 5 scores. In contrast, use of TRG did not demonstrate a significant difference in disease-free and overall survival. ILN represents a form of treatment effect and should be distinguished from UN. A modified grading system that incorporates ILN may enhance the prognostic utility of TRG.

Increased risk of severe recurrence of hepatitis C virus in liver transplant recipients of donation after cardiac death allografts.

Background. In hepatitis C virus (HCV) recipients of donation after cardiac death (DCD) grafts, there is suggestion of lower rates of graft survival, indicating that DCD grafts themselves may represent a significant risk factor for severe recurrence of HCV. Methods. We evaluated all DCD liver transplant recipients from August 2006 to February 2011 at our center. Recipients with HCV who received a DCD graft (group 1, HCV+ DCD, n=17) were compared with non-HCV recipients transplanted with a DCD graft (group 2, HCV− DCD, n=15), and with a matched group of HCV recipients transplanted with a donation after brain death (DBD) graft (group 3, HCV+ DBD, n=42). Results. A trend of poorer graft survival was seen in HCV+ patients who underwent a DCD transplant (group 1) compared with HCV− patients who underwent a DCD transplant (group 2) (P=0.14). Importantly, a statistically significant difference in graft survival was seen in HCV+ patients undergoing DCD transplant (group 1) (73%) as compared with DBD transplant (group 3) (93%)(P=0.01). There was a statistically significant increase in HCV recurrence at 3 months (76% vs. 16%) (P=0.005) and severe HCV recurrence within the first year (47% vs. 10%) in the DCD group (P=0.004). Conclusions. HCV recurrence is more severe and progresses more rapidly in HCV+ recipients who receive grafts from DCD compared with those who receive grafts from DBD. DCD liver transplantation in HCV+ recipients is associated with a higher rate of graft failure compared with those who receive grafts from DBD. Caution must be taken when using DCD grafts in HCV+ recipients.

Targeted Gene Silencing of TLR4 Using Liposomal Nanoparticles for Preventing Liver Ischemia Reperfusion Injury

RNAi‐based therapy is a promising strategy for the prevention of ischemia‐reperfusion injury (IRI). However, systemic administration of small interfering RNA (siRNA) may cause globally nonspecific targeting of all tissues, which impedes clinical use. Here we report a hepatocyte‐specific delivery system for the treatment of liver IRI, using galactose‐conjugated liposome nanoparticles (Gal‐LipoNP). Heptocyte‐specific targeting was validated by selective in vivo delivery as observed by increased Gal‐LipoNP accumulation and gene silencing in the liver. Gal‐LipoNP TLR4 siRNA treatment resulted in a significant decrease of serum alanine transferase (ALT) and aspartate transaminase (AST) in a hepatic IRI model. Histopathology displayed an overall reduction of the injury area in the Gal‐LipoNP TLR4 siRNA treated mice. Additionally, neutrophil accumulation and lipid peroxidase‐mediated tissue injury, detected by MPO, MDA and ROS respectively, were attenuated after Gal‐LipoNP TLR4 siRNA treatment. Moreover, therapeutic effects of Gal‐LipoNP TLR4 siRNA were associated with suppression of the inflammatory cytokines IL‐1 and TNF‐α. Taken together, this study is the first demonstration of liver IRI treatment using liver‐specific siRNA delivery.