Introduction: Acute liver failure (ALF) and Acute-on-chronic liver failure (ACLF) are treated with liver transplantation. Metabolic liver diseases such as phenylketonuria (PKU) and alpha-1-antitrypsin deficiency (A1ATD) can also be treated with liver transplantation. Due to the limited number of donor organs available, many patients are unable to receive a transplant. Transplant recipients are required to spend a lifetime on immune-suppressing drugs. Pediatric ALF has previously been treated via transplantation of isolated and encapsulated primary human hepatocytes (PHHs) with promising results. Herein we use Bioprinted Tissue Therapeutics (BTTs) containing PHHs and MSCs to rescue immune-competent mice with ALF and to explore the use of hepatic BTTs to treat chronic liver disease. Methods: Hepatic BTTs were created using Aspect Biosystems’ proprietary 3D bioprinting technology. BTTs are comprised of co-aggregated PHHs and MSCs suspended in a combination of solidified semi-permeable, immune-protective hydrogel biomaterials. ALF was induced via injection of CCl4 into immunocompetent mice. BTTs were implanted into either the intraperitoneal (IP) or subcutaneous (SubQ) space. Survival was recorded over 7 days. Healthy NSG mice were also implanted with BTTs to examine release of soluble A1AT. Blood was collected at regular intervals and livers were embedded for histology upon the completion of the study. Results: BTT treatment resulted in a survival rate of 78% (n=15) and 85% (n=7) in IP and SubQ implanted mice respectively, compared to 46% (IP, n=15) and 50% (SubQ, n=8) for mice receiving cell-free controls. SubQ implantation results were confirmed using PHHs from an alternate donor, wherein the survival rate for hepatic BTT-treated mice was 50% (n=8) compared to 13% for mice receiving cell-free controls. Combined the survival rate for hepatic BTT-treated mice was 68% vs 35% for mice receiving cell-free controls (P=0.003). Additionally, BTTs metabolized phenylalanine and produced A1AT. Conclusion: CCl4-induced ALF in immunocompetent mice can be successfully treated with hepatic BTTs containing primary human hepatocytes. Additionally, there is promise that this treatment could be used for chronic metabolic liver diseases. The high level of function of these devices suggests that they could be used to support liver function on an ongoing basis or to act as a bridge to transplantation or recovery. Our next step is to test a scaled up BTT for testing in rats for acute and chronic liver disease.

bioavailability.Here, we evaluate in a rat model the possible benefit against HF of encapsulated Gly in polymeric nanomicelles based on polygalacturonic acid and polyacrylic acid (Gly-NMs) previously characterized and known to increase drug bioavailability.Method: Gly and Gly-NMs role against fibrosis were tested in a CCl4induced HF rat model.Morphological, hematic and hepatic data were collected to monitor disease progression.Results: In terms of body weight, liver weight, and serum parameters of hepatic function, Gly-NM appeared to provide better recovery from hepatic fibrosis than Gly.Molecular markers and histopathological analysis showed that Gly-MN demonstrated marked antifibrotic properties, reducing collagen deposition in liver tissue and decreasing the activation of hepatic stellate cells.Furthermore, we remarked an improved CCl 4 -induced fatty-degeneration following Gly-MNs treatment.The latter was associated with a gene downregulation of carnitine palmitoyl-transferase 1A (Cpt1a) which can impose a protective action against CCl 4 insult as reported in the literature for mice lacking the enzyme. Conclusion:Our results show that encapsulated Gly reduces fibrosis and related disease markers and improve the fatty degeneration better than free drug in a in vivo rat model.

Introduction: Type 1 diabetes (T1D) is a disease characterized by elevated blood glucose due to insufficient insulin release from pancreatic β-cells. Transplantation of cadaveric islets demonstrates that cell therapy can fully reverse hyperglycemia. However, limited cell supply, immune rejection of implanted allogeneic cells, and cell survival represent major challenges. Cell encapsulation has great potential to overcome these challenges by blocking immune cell access to the grafts while allowing nutrient exchange and secreted products from the implanted cells to be delivered to the body. In this study, we use a unique microfluidic bioprinting technology to precisely control the placement of cells and biomaterials within 3D tissues with micro-architectures optimized for cellular fitness and immune protection. Methods: Living tissues consisting of fibres with a cell-containing core and immune-protective alginate-based shell were generated using Aspect Biosystems’ RX1 bioprinter technology. Core-shell fibres with reaggregated primary human pancreatic islets or embryonic stem cell-derived β-cells were tested in vitro using viability and functional (glucose-stimulated insulin secretion, GSIS) assays. Bioprinted tissues were then implanted into the IP space or omentum of streptozotocin (STZ)-induced diabetic mice and rats, respectively. Glucose homeostasis, body weight, and human C-peptide secretion were monitored for up to 3 months following implantion. Retrieved grafts were fixed and analyzed by histology (H&E, Masson’s trichrome stain) and immunohistochemistry (α-SMA, CD45) to quantify fibrotic encapsulation and immune cell infiltration. Results: Bioprinted tissues supported viability and dynamic insulin secretion of cells in vitro up to 28 days. When transplanted into immunodeficient and immunocompetent diabetic rodents, bioprinted tissues containing reaggregated human islets successfully regulated blood glucose for up to 3 months (Figure 1), although normoglycemia was only sustained in a subset of immunocompetent animals and associated with variable fibrosis. Post-retrieval viability stain, assessment of GSIS, and histology revealed high viability and functionality of implanted cells, and the absence of leukocyte infiltration through the shell. Discussion: This is the first study showing a fully 3D bioprinted tissue composed of a core/shell fibre can successfully deliver a therapeutic dose of xenogeneic cells into a diabetic animal (Figure 2). The unique features of the microfluidic technology were leveraged to bioprint an implantable and retrievable tissue patch that merges the benefits of a single fibre (cell fitness, access to nutrients, immune-protection, perm-selectivity) with those provided by a 3D structure (retrievability, ease of implant, structural integrity). The promising results obtained in rodent studies warrant further investigation to minimize fibrosis and explore the scaling-up of bioprinted tissues in large animal models of T1D.NRC-IRAP. NSERC. Stem Cell Network. Genome BC.

The brain controls all human activity — both voluntary and involuntary. Better, more functional models of the healthy and diseased human neural tissue are crucial to elucidate complex mechanisms of neurobiology, to develop reliable drug screening tools, and to provide a pathway to tissue therapeutics. Bioprinting using stem cells represents an exciting combination of technologies with tremendous potential to revolutionize the field of neuroscience. Methods are rapidly evolving that combine multiple cell types, biomaterials, and bioactive molecules in a patterned manner to mimic the complexity of the human neural tissue. Combining three-dimensional bioprinting with stem cells also provides a novel way to engineer neural tissue in a rapid and reproducible manner. Here, we cover recent developments in neural tissue engineering using various stem cell and three-dimensional bioprinting technologies and provide avenues for future work.

Conditions such as asthma and inflammatory bowel disease are characterized by aberrant smooth muscle contraction. It has proven difficult to develop human cell-based models that mimic acute muscle contraction in 2D in vitro cultures due to the nonphysiological chemical and mechanical properties of lab plastics that do not allow for muscle cell contraction. To enhance the relevance of in vitro models for human disease, we describe how functional 3D smooth muscle tissue that exhibits physiological and pharmacologically relevant acute contraction and relaxation responses can be reproducibly fabricated using a unique microfluidic 3D bioprinting technology. Primary human airway and intestinal smooth muscle cells were printed into rings of muscle tissue at high density and viability. Printed tissues contracted to physiological concentrations of histamine (0.01-100 mu M) and relaxed to salbutamol, a pharmacological compound used to relieve asthmatic exacerbations. The addition of TGF beta to airway muscle rings induced an increase in unstimulated muscle shortening and a decreased response to salbutamol, a phenomenon which also occurs in chronic lung diseases. Results indicate that the 3D bioprinted smooth muscle is a physiologically relevant in vitro model that can be utilized to study disease pathways and the effects of novel therapeutics on acute contraction and chronic tissue stenosis.

3D bioprinting offers the opportunity to automate the process of tissue engineering, which combines biomaterial scaffolds and cells to generate substitutes for diseased or damaged tissues. These bioprinting methods construct tissue replacements by positioning cells encapsulated in bioinks into specific locations in the resulting constructs. Human induced pluripotent stem cells (hiPSCs) serve as an important tool when engineering neural tissues. These cells can be expanded indefinitely and differentiated into the cell types found in the central nervous systems, including neurons. One common method for differentiating hiPSCs into neural tissue requires the formation of aggregates inside of defined diameter microwells cultured in chemically defined media. However, 3D bioprinting of such hiPSC-derived aggregates has not been previously reported in the literature, as it requires the development of specialized bioinks for supporting cell survival and differentiation into mature neural phenotypes. Here we detail methods including preparing base material components of the bioink, producing the bioink, and the steps involved in printing 3D neural tissues derived from hiPSC-derived neural aggregates using Aspect Biosystems' novel RX1 printer and their lab-on-a-printer (LOP) technology.

The hooded (hdd) floral mutant of sweet pea (Lathyrus odoratus L.) is apparently caused by loss of function of the floral developmental gene CYCLOIDEA (CYC). It has a concavely folded dorsal petal (standard) compared to the more or less flat standard of the wild type. To examine localised growth differences in wild type and hdd flowers, we printed fine-scale grids on the surfaces of sweet pea buds using inkjet technology. Wild-type standard petals have a more uniform rate of growth, whereas hdd standard petals show increased growth at their margins. The resultant lamina/margin growth differential leads to negative Gaussian curvature and can account for the differences in curvature between wild-type and hdd petals. We conclude that CYC has a role in the negative regulation of marginal petal growth in Lathyrus in order to maintain dorsal petal flatness. Differences in CYC expression and activity could possibly contribute to the range of dorsal petal form seen throughout the Fabaceae.