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

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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.

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.

Pre-emptive platelet transfusion should be avoided in non-massively transfused blunt injury victims in the absence of true or functional thrombocytopenia, as it increases risk for ARDS with no survival benefit.