Title: Potential Barriers to Human Hepatocyte Transplantation in MUP-uPAtg (+/+)Rag2-/-?C-/- Mice
Summary: Primary human fetal and adult hepatocytes have been considered feasible donor cell sources for cell transplantation. We compared the engraftment efficiencies between adult human, fetal human, and adult porcine hepatocytes after transplantation into MUP-uPAtg (+/+)Rag2-/-?C-/- mice. Transplantation of adult human hepatocytes yielded a thousand-fold higher serum albumin level compared to transplantation of fetal human hepatocytes, while transplantation of adult porcine hepatocytes resulted in a hundred-fold higher serum albumin level than adult human hepatocytes. These results suggest that adult liver cells are superior to fetal liver cells for transplantation, and caution should be applied if porcine hepatocytes are used for preclinical studies as a proof of concept for human hepatocytes.
Summary: We examined the influence of regulatory dendritic cells (DCreg), generated from cytokine-mobilized donor blood monocytes in vitamin D3 and IL-10, on renal allograft survival in a clinically relevant rhesus macaque model. DCreg expressed low MHC class II and costimulatory molecules, but comparatively high levels of programmed death ligand-1 (B7-H1), and were resistant to pro-inflammatory cytokine-induced maturation. They were infused intravenously (3.5-10 x 10(6) /kg), together with the B7-CD28 costimulation blocking agent CTLA4Ig, 7 days before renal transplantation. CTLA4Ig was given for up to 8 weeks and rapamycin, started on Day -2, was maintained with tapering of blood levels until full withdrawal at 6 months. Median graft survival time was 39.5 days in control monkeys (no DC infusion; n = 6) and 113.5 days (p < 0.05) in DCreg-treated animals (n = 6). No adverse events were associated with DCreg infusion, and there was no evidence of induction of host sensitization based on circulating donor-specific alloantibody levels. Immunologic monitoring also revealed regulation of donor-reactive memory CD95(+) T cells and reduced memory/regulatory T cell ratios in DCreg-treated monkeys compared with controls. Termination allograft histology showed moderate combined T cell- and Ab-mediated rejection in both groups. These findings justify further preclinical evaluation of DCreg therapy and their therapeutic potential in organ transplantation.
Authors: Tan C, Saurabh S, Bruchez MP, Schwartz R, Leduc P.
Title: Molecular crowding shapes gene expression in synthetic cellular nanosystems
Summary: The integration of synthetic and cell-free biology has made tremendous strides towards creating artificial cellular nanosystems using concepts from solution-based chemistry, where only the concentrations of reacting species modulate gene expression rates. However, it is known that macromolecular crowding, a key feature in natural cells, can dramatically influence biochemical kinetics via volume exclusion effects, which reduce diffusion rates and enhance binding rates of macromolecules. Here, we demonstrate that macromolecular crowding can increase the robustness of gene expression by integrating synthetic cellular components of biological circuits and artificial cellular nanosystems. Furthermore, we reveal how ubiquitous cellular modules, including genetic components, a negative feedback loop and the size of the crowding molecules can fine-tune gene circuit response to molecular crowding. By bridging a key gap between artificial and living cells, our work has implications for efficient and robust control of both synthetic and natural cellular circuits.
Authors: Phillippi JA, Green BR, Eskay MA, Kotlarczyk MP, Hill MR, Robertson AM, Watkins SC, Vorp DA, Gleason TG.
Title: Mechanism of Aortic Medial Matrix Remodeling is Distinct in Bicuspid Aortic Valve Patients
Summary: OBJECTIVES: Patients with bicuspid aortic valves (BAV) are predisposed to developing ascending thoracic aortic aneurysms (TAA) at an earlier age than patients who develop degenerative TAAs and have a tricuspid aortic valve (TAV). The hypothesis tested is that BAV associated aortopathy is mediated by a mechanism of matrix remodeling that is distinct from that seen in TAAs of patients with tricuspid aortic valves.
Authors: Gramignoli R, Dorko K, Tahan V, Skvorak KJ, Ellis E, Jorns C, Ericzon BG, Fox IJ, Strom SC.
Title: Hypothermic storage of human hepatocytes for transplantation.
Summary: Transplantation of human hepatocytes is gaining recognition as a bridge or an alternative to orthotopic liver transplantation for patients with acute liver failure and genetic defects. Since most patients require multiple cell infusions over an extended period of time, we investigated hepatic functions in cells maintained in University of Wisconsin solution at 4°C up to 72h. Eleven different assessments of hepatic viability and function were investigated both pre and post hypothermic storage, including plating efficiency, caspase 3/7 activity, ammonia metabolism and drug metabolizing capacity of isolated hepatocytes. Long-term function, basal and induced cytochrome P450 activities were measured after exposure to prototypical inducing agents. Cells from 47 different human liver specimens were analyzed. Viability significantly decreased in cells cold-stored in UW solution, while apoptosis level and plating efficiency were not significantly different from fresh cells. Luminescent and fluorescent methods assessed phase I and II activities both pre and post 24-72h of cold preservation. A robust induction (up to 200-fold) of phase I enzymes was observed in cultured cells. Phase II and ammonia metabolism remained stable during hypothermic storage although the inductive effect of culture on each metabolic activity was eventually lost. Using techniques that characterize 11 measurements of hepatic viability and function from plating efficiency, to ammonia metabolism, to phase I and II drug metabolism, it was determined that while viability decreased, the remaining viable cells in cold-stored suspensions retained critical hepatic functions for up to 48 h at levels not significantly different from those observed in freshly isolated cells.
Authors: Wells A, Grahovac J, Wheeler S, Ma B, Lauffenburger D.
Title: Targeting tumor cell motility as a strategy against invasion and metastasis.
Summary: Advances in diagnosis and treatment have rendered most solid tumors largely curable if they are diagnosed and treated before dissemination. However, once they spread beyond the initial primary location, these cancers are usually highly morbid, if not fatal. Thus, current efforts focus on both limiting initial dissemination and preventing secondary spread. There are two modes of tumor dissemination – invasion and metastasis – each leading to unique therapeutic challenges and likely to be driven by distinct mechanisms. However, these two forms of dissemination utilize some common strategies to accomplish movement from the primary tumor, establishment in an ectopic site, and survival therein. The adaptive behaviors of motile cancer cells provide an opening for therapeutic approaches if we understand the molecular, cellular, and tissue biology that underlie them. Herein, we review the signaling cascades and organ reactions that lead to dissemination, as these are non-genetic in nature, focusing on cell migration as the key to tumor progression. In this context, the cellular phenotype will also be discussed because the modes of migration are dictated by quantitative and physical aspects of the cell motility machinery.
Title: Bench to bedside review: Extracorporeal carbon dioxide removal, past present and future.
Summary: Acute respiratory distress syndrome (ARDS) has a substantial mortality rate and annually affects more than 140,000 people in the USA alone. Standard management includes lung protective ventilation but this impairs carbon dioxide clearance and may lead to right heart dysfunction or increased intracranial pressure. Extracorporeal carbon dioxide removal has the potential to optimize lung protective ventilation by uncoupling oxygenation and carbon dioxide clearance. The aim of this article is to review the carbon dioxide removal strategies that are likely to be widely available in the near future. Relevant published literature was identified using PubMed and Medline searches. Queries were performed by using the search terms ECCOR, AVCO2R, VVCO2R, respiratory dialysis, and by combining carbon dioxide removal and ARDS. The only search limitation imposed was English language. Additional articles were identified from reference lists in the studies that were reviewed. Several novel strategies to achieve carbon dioxide removal were identified, some of which are already commercially available whereas others are in advanced stages of development.
Authors: Gerlach JC, Over P, Turner ME, Thompson RL, Foka HG, Chen WC, Peault B, Gridelli B, Schmelzer E
Title: Perivascular Mesenchymal Progenitors in Human Fetal and Adult Liver
Summary: The presence of mesenchymal stem cells (MSCs) has been described in various organs. Pericytes possess a multilineage differentiation potential and have been suggested to be one of the developmental sources for MSCs. In human liver, pericytes have not been defined. Here, we describe the identification, purification, and characterization of pericytes in human adult and fetal liver. Flow cytometry sorting revealed that human adult and fetal liver contains 0.56%±0.81% and 0.45%±0.39% of CD146(+)CD45(-)CD56(-)CD34(-) pericytes, respectively. Of these, 41% (adult) and 30% (fetal) were alkaline phosphatase-positive (ALP(+)). In situ, pericytes were localized around periportal blood vessels and were positive for NG2 and vimentin. Purified pericytes could be cultured extensively and had low population doubling times. Immunofluorescence of cultures demonstrated that cells were positive for pericyte and mesenchymal cell markers CD146, NG2, CD90, CD140b, and vimentin, and negative for endothelial, hematopoietic, stellate, muscle, or liver epithelial cell markers von Willebrand factor, CD31, CD34, CD45, CD144, CD326, CK19, albumin, α-fetoprotein, CYP3A7, glial fibrillary acid protein, MYF5, and Pax7 by gene expression; myogenin and alpha-smooth muscle actin expression were variable. Fluorescence-activated cell sorting analysis of cultures confirmed surface expression of CD146, CD73, CD90, CD10, CD13, CD44, CD105, and ALP and absence of human leukocyte antigen-DR. In vitro differentiation assays demonstrated that cells possessed robust osteogenic and myogenic, but low adipogenic and low chondrogenic differentiation potentials. In functional in vitro assays, cells had typical mesenchymal strong migratory and invasive activity. In conclusion, human adult and fetal livers harbor pericytes that are similar to those found in other organs and are distinct from hepatic stellate cells.
Authors: Jennifer L Collinger, Brian Wodlinger, John E Downey, Wei Wang, Elizabeth C Tyler-Kabara, Douglas J Weber, Angus JC McMorland, Meel Velliste, Michael L Boninger, Andrew B Schwartz
Title: High-performance neuroprosthetic control by an individual with tetraplegia
Paralysis or amputation of an arm results in the loss of the ability to orient the hand and grasp, manipulate, and carry objects, functions that are essential for activities of daily living. Brain—machine interfaces could provide a solution to restoring many of these lost functions. We therefore tested whether an individual with tetraplegia could rapidly achieve neurological control of a high-performance prosthetic limb using this type of an interface.