Long term outcomes of abdominal wall reconstruction using open component separation and biologic mesh in the liver, kidney, and small bowel transplant population.

PURPOSE: The aim of this study is to critically examine the multidisciplinary approach to abdominal wall reconstruction (AWR) in the solid organ transplant (SOT) population at our institution, MedStar Georgetown University Hospital, using a modified component separation technique (CST). METHODS: A retrospective review of AWR utilizing modified open CST with biologic mesh in SOT patients was performed from January 2010 to June 2018. Patient demographics, comorbidities, operative details, complications, and outcomes were recorded. Descriptive statistics, logistic and linear regression analyses were performed to appraise outcomes. RESULTS: Thirty-five patients were included; mean age was 53 years. Patient demographics and comorbidities were: 82.9% male, 45.7% history of tobacco use, and 28.6% diabetes. Fifty-one percent had undergone prior hernia repair. Transplant types were: kidney (9), liver (16), liver/kidney (1), small bowel (7), multivisceral (2). All were on an immunosuppressive regimen at time of surgery; 22.9% included steroids. Average defect size was 361 cm2. Additional soft tissue procedures were performed in 65.7% (n = 23) of patients. Median time to healing was 29.0 days. Complication rate was 31.4% (n = 11); six patients required reoperation within 90 days. Recurrence rate was 5.7% (n = 2) at mean of follow up of 3.0 years. Additional soft tissue procedures were statistically significant for healing time (p = 0.037). Steroid use was statistically significant for reoperation within 90 days (OR = 12.500; 95% CI 1.694-92.250); however, steroid use was not significant after correction for confounders. CONCLUSION: Modified open CST with biologic mesh is a safe, efficacious approach to complex AWR in the SOT population with recurrence rates comparable to the general population.

HDAC1 and HDAC2 integrate the expression of p53 mutants in pancreatic cancer.

Mutation of p53 is a frequent genetic lesion in pancreatic cancer being an unmet clinical challenge. Mutants of p53 have lost the tumour-suppressive functions of wild type p53. In addition, p53 mutants exert tumour-promoting functions, qualifying them as important therapeutic targets. Here, we show that the class I histone deacetylases HDAC1 and HDAC2 contribute to maintain the expression of p53 mutants in human and genetically defined murine pancreatic cancer cells. Our data reveal that the inhibition of these HDACs with small molecule HDAC inhibitors (HDACi), as well as the specific genetic elimination of HDAC1 and HDAC2, reduce the expression of mutant p53 mRNA and protein levels. We further show that HDAC1, HDAC2 and MYC directly bind to the TP53 gene and that MYC recruitment drops upon HDAC inhibitor treatment. Therefore, our results illustrate a previously unrecognized class I HDAC-dependent control of the TP53 gene and provide evidence for a contribution of MYC. A combined approach targeting HDAC1/HDAC2 and MYC may present a novel and molecularly defined strategy to target mutant p53 in pancreatic cancer.

Cyclosporine A Inhibits the T-bet-Dependent Antitumor Response of CD8(+) T Cells.

Transplant recipients face an increased risk of cancer compared with the healthy population. Although several studies have examined the direct effects of immunosuppressive drugs on cancer cells, little is known about the interactions between pharmacological immunosuppression and cancer immunosurveillance. We investigated the different effects of rapamycin (Rapa) versus cyclosporine A (CsA) on tumor-reactive CD8(+) T cells. After adoptive transfer of CD8(+) T cell receptor-transgenic OTI T cells, recipient mice received either skin grafts expressing ovalbumin (OVA) or OVA-expressing B16F10 melanoma cells. Animals were treated daily with Rapa or CsA. Skin graft rejection and tumor growth as well as molecular and cellular analyses of skin- and tumor-infiltrating lymphocytes were performed. Both Rapa and CsA were equally efficient in prolonging skin graft survival when applied at clinically relevant doses. In contrast to Rapa-treated animals, CsA led to accelerated tumor growth in the presence of adoptively transferred tumor-reactive CD8(+) OTI T cells. Further analyses showed that T-bet was downregulated by CsA (but not Rapa) in CD8(+) T cells and that cancer cytotoxicity was profoundly inhibited in the absence of T-bet. CsA reduces T-bet-dependent cancer immunosurveillance by CD8(+) T cells. This may contribute to the increased cancer risk in transplant recipients receiving calcineurin inhibitors.

Developments in immunotherapy for gastrointestinal cancer.

Gastrointestinal (GI) cancers are the most commonly occurring cancer worldwide. Colorectal cancer (CRC) is the second and third most commonly diagnosed cancer in women and men, respectively. Despite the advent of screening and the declining incidence of CRC overall, most patients are not diagnosed at an early, localized stage. Due to resistance to chemotherapy, recurrence, and metastatic disease, those diagnosed with advanced disease have only a 12% 5-year survival rate. Given the overwhelming global impact of CRC, the need for advanced therapy is crucial. Targeted immunotherapy in addition to surgical resection, traditional chemotherapy, and radiation therapy is on the rise. For the purpose of this review, we focused on the advances of immunotherapy, particularly in CRC, with mention of research pertaining to particular advances in immunotherapy for other aspects of the GI system. We review basic immunology and the microenvironment surrounding colorectal tumors that lead to immune system evasion and poor responses to chemotherapy. We also examined the way these obstacles are proving to be the targets of tumor specific immunotherapy. We will present current FDA approved immunotherapies such as monoclonal antibodies (mAb) targeting tumor specific antigens, as well as vaccines, adoptive cell therapy, cytokines, and check-point inhibitors. A summation of prior research, current clinical trials, and prospective therapies in murine models help delineate our current status and future strategies on CRC immunotherapy.

mTOR inhibition improves fibroblast growth factor receptor targeting in hepatocellular carcinoma.

BACKGROUND: Systemic therapy has proven only marginal effects in hepatocellular carcinoma (HCC) so far. The aim of this study was to evaluate the effect of targeting fibroblast growth factor receptor (FGFR) on tumour and stromal cells in HCC models. METHODS: Human and murine HCC cells, endothelial cells (ECs), vascular smooth muscle cells (VSMCs), hepatic stellate cells (HSCs), human HCC samples, FGFR inhibitor BGJ398 and mammalian target of rapamycin (mTOR) inhibitor rapamycin were used. Effects on growth, motility, signalling and angiogenic markers were determined. In vivo subcutaneous and syngeneic orthotopic tumour models were used. RESULTS: In tumour cells and ECs, targeting FGFR showed significant inhibitory effects on signalling and motility. Minor effects of FGFR inhibition were observed on VSMCs and HSCs, which were significantly enhanced by combining FGFR and mTOR blockade. In vivo daily (5 mg kg(-1)) treatment with BGJ398 led to a significant growth inhibition in subcutaneous tumour models, but only a combination of FGFR and mTOR blockade impaired tumour growth in the orthotopic model. This was paralleled by reduced tumour cell proliferation, vascularisation, pericytes and increased apoptosis. CONCLUSIONS: Targeting FGFR with BGJ398 affects tumour cells and ECs, whereas only a combination with mTOR inhibition impairs recruitment of VSMCs and HSCs. Therefore, this study provides evidence for combined FGFR/mTOR inhibition in HCC.

Mesenchymal stem cells are short-lived and do not migrate beyond the lungs after intravenous infusion.

Mesenchymal stem cells (MSC) are under investigation as a therapy for a variety of disorders. Although animal models show long term regenerative and immunomodulatory effects of MSC, the fate of MSC after infusion remains to be elucidated. In the present study the localization and viability of MSC was examined by isolation and re-culture of intravenously infused MSC. C57BL/6 MSC (500,000) constitutively expressing DsRed-fluorescent protein and radioactively labeled with Cr-51 were infused via the tail vein in wild-type C57BL/6 mice. After 5 min, 1, 24, or 72 h, mice were sacrificed and blood, lungs, liver, spleen, kidneys, and bone marrow removed. One hour after MSC infusion the majority of Cr-51 was found in the lungs, whereas after 24 h Cr-51 was mainly found in the liver. Tissue cultures demonstrated that viable donor MSC were present in the lungs up to 24 h after infusion, after which they disappeared. No viable MSC were found in the other organs examined at any time. The induction of ischemia-reperfusion injury in the liver did not trigger the migration of viable MSC to the liver. These results demonstrate that MSC are short-lived after i.v. infusion and that viable MSC do not pass the lungs. Cell debris may be transported to the liver. Long term immunomodulatory and regenerative effects of infused MSC must therefore be mediated via other cell types.

High resolution ultrasound including elastography and contrast-enhanced ultrasound (CEUS) for early detection and characterization of liver lesions in the humanized tumor mouse model.

PURPOSE: In this study we investigated the sensitivity of high resolution ultrasound (HRU) in the detection of small liver tumors and its microcirculation in a humanized tumor mouse model (HTM). These mice develop a complete human immune system and human breast cancer growth in the liver which allows the investigation of antibody based immunotherapies under human like conditions. METHOD: HTM were generated by the co-transplantation of human breast cancer cells and human hematopoietic stem cells. HRU, Doppler sonography (CCDS), contrast enhanced ultrasound (CEUS) and color-coded elastography were performed on all HTM and confirmed by histopathological assessment. RESULTS: Using HRU and CEUS, noncystic solid liver lesions between 2 and 11 mm (mean 3.5 mm) size were detectable in HTM. Granulomatous areas were identified by B-scan imaging, showing areas of higher stiffness in elastography and areas without contrast media uptake in the late phase (CEUS). In addition, CEUS detected capillary microcirculation of benign and malignant liver lesions smaller than 10 mm. CONCLUSION: Beyond human breast cancer HTM additionally developed small parenchymal liver lesions, which could be characterized by HRU in combination with CEUS and elastography in-vivo. Nevertheless, the defined diagnoses of solid liver lesions less than 5 mm require confirmation by histopathology.

Eosinophilic cholangitis and wirsungitis as cause of simultaneous bile duct obstruction and pancreatitis.

Eosinophilic cholangitis is a rare clinical entity characterised by transmural eosinophilic infiltration of the biliary system. The aetiology of this disease is still unclear. We report on a 49-year-old male patient who presented with symptoms of obstructive jaundice and imaging suggestive for periampullary carcinoma. After partial pancreatoduodenectomy for suspected pancreatic cancer, pathology revealed massive eosinophilic cholecystitis as well as intra- and extrahepatic eosinophilic cholangitis with pseudopolypoid papillary lesions. Our case illustrates the diagnostic pitfalls in eosinophilic cholangitis as careful imaging procedures - optimally interdisciplinary - should be considered and performed in such patients. In conclusion, eosinophilic cholangitis is an uncommon, inflammatory condition that needs to be considered as a differential diagnosis for periampullary malignancies.