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The mammalian liver's regenerative ability has led researchers to engineer animals as incubators for expansion of human hepatocytes. The expansion properties of human hepatocytes in immunodeficient...

Organ bioengineering offers a promising solution to the persistent shortage of donor organs. However, the progression of this technology toward clinical use has been hindered by the challenges of reconstituting a functional vascular network, directing the engraftment of specific functional cell types, and defining appropriate culture conditions to concurrently support the health and phenotypic stability of diverse cell lineages. We previously demonstrated the ability to functionally reendothelialize the vasculature of a clinically scaled decellularized liver scaffold with human umbilical vein endothelial cells (HUVECs) and to sustain continuous perfusion in a large animal recovery model. We now report a method for seeding and engrafting primary porcine hepatocytes into a bioengineered liver (BEL) scaffold previously reendothelialized with HUVECs. The resulting BELs were competent for albumin production, ammonia detoxification and urea synthesis, indicating the presence of a functional hepatocyte compartment. BELs additionally slowed ammonia accumulation during in vivo perfusion in a porcine model of surgically induced acute liver failure. Following explant of the graft, BEL parenchyma showed maintenance of canonical endothelial and hepatocyte markers. Taken together, these results support the feasibility of engineering a clinically scaled functional BEL and establish a platform for optimizing the seeding and engraftment of additional liver specific cells. Anderson et al. demonstrate a method for seeding and engrafting primary porcine hepatocytes into a bioengineered liver (BEL) scaffold previously reendothelialized with HUVECs. This study constitutes an important advance in the effort to generate transplantable livers of a clinically relevant size for humans.

BACKGROUND: Biliary complications (strictures and leaks), represent major limitations in living-donor liver transplantation. Mesenchymal stem cells (MSC) are a promising modality to prevent biliary complications owing to immunosuppressive and angiogenic properties. Our goal was to evaluate the safety of adipose-derived MSC delivery to biliary anastomoses in a porcine model. Secondary objectives were defining the optimal method of delivery (intraluminal vs extraluminal) and to investigate MSC engraftment, angiogenesis, and fibrosis. METHODS: Pigs were divided into three groups. Animals underwent adipose collection, MSC isolation, and expansion. Two weeks later, animals underwent bile duct transection, re-anastomosis, and stent insertion. Group 1 received plastic stents wrapped in unseeded vicryl mesh; Group 2 received stents wrapped in MSC-seeded mesh; Group 3 received unwrapped stents with the anastomosis immersed in an MSC-suspension. Animals were sacrificed one month after stent insertion when cholangiograms and biliary tissue were obtained. Serum was collected for liver biochemistries. Tissue was used for hematoxylin/eosin/trichrome staining and immunohistochemistry for MSC markers (CD44 and CD34) and a marker of neo-angiogenesis (CD31). RESULTS: There were no intra-operative complications. One pig died on post-operative day three due to acute cholangitis. All others recovered without complications. Cholangiography demonstrated no biliary leaks and minimal luminal narrowing. Surviving animals exhibited no symptoms, abnormal liver biochemistries, or clinically-significant biliary stricturing. Group 3 showed significantly greater CD44 and CD34 staining, indicating MSC engraftment. Fibrosis was reduced at the anastomotic site in Group 3 based on trichrome stain. CD31 staining of Group 3 was more pronounced, supporting enhanced neo-angiogenesis. CONCLUSION: Adipose-derived MSC were safely applied to biliary anastomoses. MSC were locally engrafted within the bile duct and may have beneficial effects in terms of fibrosis and angiogenesis.

Meckel’s diverticulum (MD) is the most common congenital anomaly of the gastrointestinal tract. Its course is usually benign but may also result in complications requiring surgical intervention. A diverticulum may also permit the removal of intraluminal objects without bowel resection and anastomosis. A woman in her 50s was found to have a mechanical small bowel obstruction secondary to an intraluminal mass within the terminal ileum. On exploration, an MD was encountered proximal to the mass. A diverticulectomy was performed after maneuvering the enterolith into the diverticulum. Meckel’s diverticulum with an associated enterolith is a rare cause of small bowel obstruction. Historic imaging may show long-standing stones in the bowel lumen and provide a diagnostic clue. Diverticulectomy may be performed to reduce the risks of small bowel resection and anastomosis. This technique can be used for other intraluminal objects requiring removal in the presence of an MD.

Summary A reliable source of human hepatocytes and transplantable livers is needed. Interspecies embryo complementation, which involves implanting donor human stem cells into early morula/blastocyst stage animal embryos, is an emerging solution to the shortage of transplantable livers. We review proposed mutations in the recipient embryo to disable hepatogenesis, and discuss the advantages of using fumarylacetoacetate hydrolase knockouts and other genetic modifications to disable hepatogenesis. Interspecies blastocyst complementation using porcine recipients for primate donors has been achieved, although percentages of chimerism remain persistently low. Recent investigation into the dynamic transcriptomes of pigs and primates have created new opportunities to intimately match the stage of developing animal embryos with one of the many varieties of human induced pluripotent stem cell. We discuss techniques for decreasing donor cell apoptosis, targeting donor tissue to endodermal structures to avoid neural or germline chimerism, and decreasing the immunogenicity of chimeric organs by generating donor endothelium., In this article, Nyberg and colleagues discuss the possibility of generating human livers through interspecies blastocyst complementation, review candidate hepatogenesis-disabling mutations in recipient blastocysts with a focus on fumarylacetoacetate hydrolase knockouts as an advantageous model, and present recent advances in blastocyst complementation to improve the effectiveness and ethics of interspecies hepatogenesis.

Owing to the increasing worldwide burden of liver diseases, the crucial need for safe and effective interventions for treating end-stage liver failure has been a very productive line of inquiry in the discipline of hepatology for many years. Liver transplantation is recognized as the most effective treatment for end-stage liver disease; however, the shortage of donor organs, high medical costs, and lifelong use of immunosuppressive agents represent major drawbacks and demand exploration for alternative treatments. Stem cell-based therapies have been widely studied in the field of liver diseases and are considered to be among the most promising therapies. Herein, we review recent advances in the application of stem cell-related therapies in liver disease with the aim of providing readers with relevant knowledge in this field and inspiration to spur further inquiry.

Robotic Surgery is becoming increasingly used in general surgery. The objective of this study is to evaluate the safety, effectiveness and short-term (less than 1 year) outcomes of Robotic Paraesophageal Hernia (RPEH) Surgery using the DaVinci Surgical Robot system (Intuitive Surgical, CA) in a large community hospital. This is a retrospective cohort study of 28 consecutive patients who underwent robotic paraesophageal hernia repair January 2011-March 2013 in this institution. Data and outcomes collected for analysis include patient demographics, operating times, conversion, complications, mortality and recurrence. The mean age of the patients was 68.7 +/- 12.7 years, 82% were females and the mean BMI was 29 +/- 6.3. The mean operative time, including the robot docking time, was 83.6 + 24 min. The average length of hospital stay (LOS) was 2.8 +/- 1.9 days. There were no conversions to open or laparoscopic procedures. Postoperative complications were noted in 3 patients (10.7%), including one mortality (3.4%). One symptomatic recurrence (3.4%) was noted during the 12-month follow-up period. Robotic Paraesophageal repair is a safe (similar rate of complication and mortality to literature for laparoscopic procedure) and an effective (paraeshopageal hernia repaired without high recurrence) procedure with acceptable complication rates even in older patients with high operative risks.

Tissue regeneration is a process by which the remaining cells of an injured organ regrow to offset the missed cells. This field is relatively a new discipline that has been a focus of intense research by clinicians, surgeons, and scientists for decades. It constitutes the cornerstone of tissue engineering, creation of artificial organs, and generation and utilization of therapeutic stem cells to undergo transformation to different types of mature cells. Many medical experts, scientists, biologists, and bioengineers have dedicated their efforts to deeply comprehend the process of liver regeneration, striving for harnessing it to invent new therapies for liver failure. Liver regeneration after partial hepatectomy in rodents has been extensively studied by researchers for many years. It is divided into three important distinctive phases including (a) Initiation or priming phase which includes an overexpression of specific genes to prepare the liver cells for replication, (b) Proliferation phase in which the liver cells undergo a series of cycles of cell division and expansion and finally, (c) termination phase which acts as brake to stop the regenerative process and prevent the liver tissue overgrowth. These events are well controlled by cytokines, growth factors, and signaling pathways. In this review, we describe the function, embryology, and anatomy of human liver, discuss the molecular basis of liver regeneration, elucidate the hepatocyte and cholangiocyte lineages mediating this process, explain the role of hepatic progenitor cells and elaborate the developmental signaling pathways and regulatory molecules required to procure a complete restoration of hepatic lobule. This article is categorized under: Adult Stem Cells, Tissue Renewal, and Regeneration > Regeneration Signaling Pathways > Global Signaling Mechanisms Gene Expression and Transcriptional Hierarchies > Cellular Differentiation.

Implanted bioengineered livers have not exceeded three days of continuous perfusion. Here we show that decellularized whole porcine livers revascularized with human umbilical vein endothelial cells and implanted heterotopically into immunosuppressed pigs whose spleens had been removed can sustain perfusion for up to 15 days. We identified peak glucose consumption rate as a main predictor of the patency of the revascularized bioengineered livers (rBELs). Heterotopic implantation of rBELs into pigs in the absence of anticoagulation therapy led to sustained perfusion for three days, followed by a pronounced immune responses directed against the human endothelial cells. A 10 day steroid-based immunosuppression protocol and a splenectomy at the time of rBEL implantation reduced the immune responses and resulted in continuous perfusion of the rBELs for over two weeks. We also show that the human endothelial cells in the perfused rBELs colonize the liver sinusoids and express sinusoidal endothelial markers similar to those in normal liver tissue. Revascularized liver scaffolds that can maintain blood perfusion at physiological pressures might eventually help to overcome the chronic shortage of transplantable human livers. Decellularized whole porcine livers revascularized with human endothelial cells and implanted heterotopically into immunosuppressed pigs whose spleens had been removed can sustain perfusion for up to 15 days.

While damage control resuscitation is known to confer a survival advantage in severely injured patients, high-ratio blood component therapy should be initiated only in carefully selected trauma patients, due to the morbidity associated with blood product use. With this project, we aim to identify the effect of platelet transfusion in non-massively transfused bluntly injured patients. The Glue Grant database was retrospectively queried and severely injured blunt trauma patients who underwent non-massive transfusion were identified. Patients were divided into quartiles depending on platelet volume they were transfused in the first 48 h. Outcomes of interest included mortality; ventilator, Intensive Care Unit (ICU) and hospital length of stay (LOS); infectious and non-infectious complications. Multivariable regression models were fitted for these outcomes, controlling for age, pre-existing comorbidities, injury severity, acute physiologic derangement, neurologic injury burden, and other fluid and blood product resuscitation. There was no difference in mortality, LOS, or the incidence of multi-organ failure and infectious complications. However, patients receiving ≥ 250 mL of platelets were more likely to develop acute respiratory distress syndrome (ARDS) compared to those who received

The liver is has a high capacity for endogenous regeneration and repair. Therefore, the use of stem cells to promote and harness natural liver regeneration is a promising approach to a number of liver diseases that are otherwise dependent on whole-organ liver transplantation, a solution that is severely limited by the shortage of donor livers. Several forms of stem cell therapy involving different stem cell sources have been tested for the treatment of acute and chronic liver failure, as well as congenital metabolic disorders, with varying levels of preclinical and clinical success. These therapies may serve as a bridge to liver transplantation or to endogenous liver regeneration, or in conjunction with gene therapy may be curative for congenital metabolic disorders. Stem cell-derived hepatocyte-like cells hold promise for use in cell transplantation, bioartificial liver devices, and bioengineered organs, and are starting to play an important role in disease modeling, drug development, and toxicity testing. Their capacity for self-renewal and differentiation, together with the liver's innate regenerative ability, make them ideal candidates for the treatment of liver disease.