scholarly journals Bioengineered Livers: A New Tool for Drug Testing and a Promising Solution to Meet the Growing Demand for Donor Organs

2016 ◽  
Vol 57 (3-4) ◽  
pp. 224-239 ◽  
Author(s):  
Franziska Mußbach ◽  
Utz Settmacher ◽  
Olaf Dirsch ◽  
Chichi Xie ◽  
Uta Dahmen
Keyword(s):  
Drug Testing ◽  
Vascular System ◽  
Observation Time ◽  
Heterotopic Transplantation ◽  
Physiological Models ◽  
Innovative Strategy ◽  
Pharmacological Research ◽  
Organ Specific ◽  
Static Conditions ◽  
Donor Organs

Background: Organ engineering is a new innovative strategy to cope with two problems: the need for physiological models for pharmacological research and donor organs for transplantation. A functional scaffold is generated from explanted organs by removing all cells (decellularization) by perfusing the organ with ionic or nonionic detergents via the vascular system. Subsequently the acellular scaffold is reseeded with organ-specific cells (repopulation) to generate a functional organ. Summary: This review gives an overview of the state of the art describing the decellularization process, the subsequent quality assessment, the repopulation techniques and the functional assessment. It emphasizes the use of scaffolds as matrix for culturing human liver cells for drug testing. Further, it highlights the techniques for transplanting these engineered scaffolds in allogeneic or xenogeneic animals in order to test their biocompatibility and use as organ grafts. Key Messages: The first issue is the so-called decellularization, which is best explored and resulted in a multitude of different protocols. The most promising approach seems to be the combination of pulsatile perfusion of the liver with Triton X-100 and SDS via hepatic artery and portal vein. Widely accepted parameters of quality control include the quantitative assessment of the DNA content and the visualization of eventually remaining nuclei confirmed by HE staining. Investigations regarding the composition of the extracellular matrix focused on histological determination of laminin, collagen, fibronectin and elastin and remained qualitatively. Repopulation is the second issue which is addressed. Selection of the most suitable cell type is a highly controversial topic. Currently, the highest potential is seen for progenitor and stem cells. Cells are infused into the scaffold and cultured under static conditions or in a bioreactor allowing dynamic perfusion of the scaffold. The quality of repopulation is mainly assessed by routine histology and basic functional assays. These promising results prompted to consider the use of a liver scaffold repopulated with human cells for pharmacological research. Transplantation of the (repopulated) scaffold is the third topic which is not yet widely addressed. Few studies report the heterotopic transplantation of repopulated liver tissue without vascular anastomosis. Even fewer studies deal with the heterotopic transplantation of a scaffold or a repopulated liver lobe. However, observation time was still limited to hours, and long-term graft survival has not been reported yet. These exciting results emphasize the potential of this new and promising strategy to create physiological models for pharmacological research and to generate liver grafts for the transplant community to treat organ failure. However, the scientific need for further development in the field of liver engineering is still tremendous.

scholarly journals HGG-36. HIF-2: A NEW DRUG TARGET IN PEDIATRIC HIGH-GRADE GLIOMA WITH PROMISING PRECLINICAL RESULTS

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii350-iii350
Author(s):  
Quentin Fuchs ◽  
Marina Pierrevelcin ◽  
Christophe Papin ◽  
Monique Dontenwill ◽  
Natacha Entz-Werlé
Keyword(s):  
Drug Testing ◽  
Treatment Resistance ◽  
High Grade Glioma ◽  
Clinical Work ◽  
Driver Mutations ◽  
High Grade ◽  
Innovative Strategy ◽  
Dismal Prognosis ◽  
Cell Arrest ◽  
And Migration

Abstract Pediatric high-grade gliomas (pHGGs) have a very dismal prognosis and need new innovative strategy for treatment. Despite the past discovery of histone H3 driver mutations, we are not able for instance to stop this induced epigenetic remodulation. Therefore, proactive translational studies wish to go further discovering new targetable proteins in pHGG. In our past clinical work, we were able to link significantly HIF-2alpha to a worse pHGG outcome and to their treatment resistance. We designed this new work to determine in several patient-derived cell lines (6 PDCLs) with or without H3.3 mutation the variation of HIF-2alpha, its role, its induction in normoxic and hypoxic microenvironment and its transcriptional targets using RNAseq, metabolomics and ChipSeq analyses. Complementary functional analyses were performed using siRNA strategy during cultures and migration assays. Finally, preclinical drug testing involving commercialized and non-commercialized HIF-2alpha specific inhibitors in the same PDCLs were evaluating their antiproliferative and pro-apoptotic effect. Our results confirmed the central role of HIF-2alpha in cell resistance to treatment, in pHGG stemness features and its direct link with metabolism adaptation and histone interaction. After the confirmation of its frequent presence in multiple PDCLs initiated from thalamic pHGGs and DIPG, we were using inhibitors in a single and combinatorial strategy targeting HIF-2alpha plus another hypoxia biomarker (mTor). This preclinical targeting was highly effective to favor cell arrest, apoptosis and to stop cell migration. In conclusion, HIF-2alpha seem to be a major biomarker in pHGGs that might be targeted giving a useful new opportunity for pHGG treatments.

scholarly journals Gravity-Based Flow Efficient Perfusion Culture System for Spheroids Mimicking Liver Inflammation

Biomedicines ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1369
Author(s):  
Young-Su Kim ◽  
Arun Asif ◽  
Abdul Rahim Chethikkattuveli Salih ◽  
Jae-Wook Lee ◽  
Ki-Nam Hyun ◽  
...  
Keyword(s):  
Culture System ◽  
Disease Modeling ◽  
Perfusion Culture ◽  
Drug Analysis ◽  
Culture Conditions ◽  
Current Approach ◽  
Spheroid Culture ◽  
Organ Specific ◽  
Static Conditions

The spheroid culture system provides an efficient method to emulate organ-specific pathophysiology, overcoming the traditional two-dimensional (2D) cell culture limitations. The intervention of microfluidics in the spheroid culture platform has the potential to enhance the capacity of in vitro microphysiological tissues for disease modeling. Conventionally, spheroid culture is carried out in static conditions, making the media nutrient-deficient around the spheroid periphery. The current approach tries to enhance the capacity of the spheroid culture platform by integrating the perfusion channel for dynamic culture conditions. A pro-inflammatory hepatic model was emulated using a coculture of HepG2 cell line, fibroblasts, and endothelial cells for validating the spheroid culture plate with a perfusable channel across the spheroid well. Enhanced proliferation and metabolic capacity of the microphysiological model were observed and further validated by metabolic assays. A comparative analysis of static and dynamic conditions validated the advantage of spheroid culture with dynamic media flow. Hepatic spheroids were found to have improved proliferation in dynamic flow conditions as compared to the static culture platform. The perfusable culture system for spheroids is more physiologically relevant as compared to the static spheroid culture system for disease and drug analysis.

scholarly journals Systemically Administered, Target-Specific, Multi-Functional Therapeutic Recombinant Proteins in Regenerative Medicine

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 226 ◽  
Author(s):  
Tero A.H. Järvinen ◽  
Toini Pemmari
Keyword(s):  
Regenerative Medicine ◽  
Blood Vessels ◽  
Recombinant Proteins ◽  
Clinical Medicine ◽  
Vascular System ◽  
Therapeutic Potential ◽  
Systemic Administration ◽  
Molecular Signature ◽  
Postal Code ◽  
Organ Specific

Growth factors, chemokines and cytokines guide tissue regeneration after injuries. However, their applications as recombinant proteins are almost non-existent due to the difficulty of maintaining their bioactivity in the protease-rich milieu of injured tissues in humans. Safety concerns have ruled out their systemic administration. The vascular system provides a natural platform for circumvent the limitations of the local delivery of protein-based therapeutics. Tissue selectivity in drug accumulation can be obtained as organ-specific molecular signatures exist in the blood vessels in each tissue, essentially forming a postal code system (“vascular zip codes”) within the vasculature. These target-specific “vascular zip codes” can be exploited in regenerative medicine as the angiogenic blood vessels in the regenerating tissues have a unique molecular signature. The identification of vascular homing peptides capable of finding these unique “vascular zip codes” after their systemic administration provides an appealing opportunity for the target-specific delivery of therapeutics to tissue injuries. Therapeutic proteins can be “packaged” together with homing peptides by expressing them as multi-functional recombinant proteins. These multi-functional recombinant proteins provide an example how molecular engineering gives to a compound an ability to home to regenerating tissue and enhance its therapeutic potential. Regenerative medicine has been dominated by the locally applied therapeutic approaches despite these therapies are not moving to clinical medicine with success. There might be a time to change the paradigm towards systemically administered, target organ-specific therapeutic molecules in future drug discovery and development for regenerative medicine.

scholarly journals Visualization of vascular mural cells in developing brain using genetically labeled transgenic reporter mice

2017 ◽  
Vol 38 (3) ◽  
pp. 456-468 ◽  
Author(s):  
Bongnam Jung ◽  
Thomas D Arnold ◽  
Elisabeth Raschperger ◽  
Konstantin Gaengel ◽  
Christer Betsholtz
Keyword(s):  
Vascular System ◽  
Growth Factor Receptor ◽  
Cell Labeling ◽  
Reporter Expression ◽  
Mural Cell ◽  
Mural Cells ◽  
Reporter Mice ◽  
Organ Specific ◽  
The Central Nervous System ◽  
Suitable Marker

The establishment of a fully functional blood vascular system requires elaborate angiogenic and vascular maturation events in order to fulfill organ-specific anatomical and physiological needs. Although vascular mural cells, i.e. pericytes and vascular smooth muscle cells, are known to play fundamental roles during these processes, their characteristics during vascular development remain incompletely understood. In this report, we utilized transgenic reporter mice in which mural cells are genetically labeled to examine developing vascular mural cells in the central nervous system (CNS). We found platelet-derived growth factor receptor β gene ( Pdgfrb)-driven EGFP reporter expression as a suitable marker for vascular mural cells at the earliest stages of mouse brain vascularization. Furthermore, the combination of Pdgfrb and NG2 gene (Cspg4) driven reporter expression increased the specificity of brain vascular mural cell labeling at later stages. The expression of other known pericyte markers revealed time-, region- and marker-specific patterns, suggesting heterogeneity in mural cell maturation. We conclude that transgenic reporter mice provide an important tool to explore the development of CNS pericytes in health and disease.

scholarly journals Systemically Administered, Target-specific, Multi-functional Therapeutic Recombinant Proteins in Regenerative Medicine

2019 ◽  
Author(s):  
Tero Järvinen ◽  
Toini Pemmari
Keyword(s):  
Regenerative Medicine ◽  
Recombinant Proteins ◽  
Clinical Medicine ◽  
Vascular System ◽  
Therapeutic Potential ◽  
Systemic Administration ◽  
Molecular Engineering ◽  
Molecular Signature ◽  
Postal Code ◽  
Organ Specific

Growth factors, chemokines and cytokines guide tissue regeneration after injuries. However, their applications as recombinant proteins are almost non-existent due to the difficulty of maintaining their bioactivity in the protease-rich milieu of injured tissues in humans. Safety concerns have ruled out their systemic administration. The vascular system provides a natural platform for circumvent the limitations of the local delivery of protein-based therapeutics. Tissue selectivity in drug accumulation can be obtained as organ-specific molecular signatures exist in the blood vessels in each tissue, essentially forming a postal code system (“vascular zip codes”) within the vasculature. These target-specific “vascular zip codes” can be exploited in regenerative medicine as the angiogenic vasculature forming in the regenerating tissues has a unique molecular signature. The identification of vascular homing peptides capable of finding these unique “vascular zip codes” after their systemic administration provides an opportunity for the target-specific delivery of therapeutics to tissue injuries. Therapeutic proteins can be “packaged” together with homing peptides by expressing them as multi-functional recombinant proteins. These multi-functional recombinant proteins provide an example how molecular engineering gives a compound an ability to home to regenerating tissue and enhance its therapeutic potential. Regenerative medicine has been dominated by the locally applied therapeutic approaches despite these therapies are not moving to clinical medicine with success. There might be a time to change the paradigm towards systemically administered, target organ-specific therapeutic molecules in future drug discovery and development for regenerative medicine

A Dynamic Boundary Condition for the Pulmonary Vasculature

2008 ◽  
Author(s):  
Rachel B. Clipp ◽  
Brooke N. Steele
Keyword(s):  
Blood Pressure ◽  
Boundary Condition ◽  
Blood Flow ◽  
Computational Models ◽  
Vascular System ◽  
Region Of Interest ◽  
Pulmonary Vasculature ◽  
Dynamic Boundary Condition ◽  
Organ Specific ◽  
Specific Geometry

Computational models can be used to predict the blood pressure and blood flow in a region of interest within the vascular system. To provide an accurate model, it is important to consider the organ-specific properties of the region of interest and apply those properties to the model. The pulmonary vasculature has several organ-specific properties, including the vessel compliance, specific geometry and respiratory process [1,2].

scholarly journals Therapeutic application of recombinant human ADAMTS-13 improves shock reversal and coagulation status in a trauma hemorrhage and transfusion rat model

2020 ◽  
Vol 8 (S1) ◽  
Author(s):  
Mathijs R. Wirtz ◽  
Daan P. van den Brink ◽  
Joris J. T. H. Roelofs ◽  
J. Carel Goslings ◽  
Nicole P. Juffermans
Keyword(s):  
Organ Failure ◽  
Vascular System ◽  
Organ Damage ◽  
Endothelial Damage ◽  
Endothelial Injury ◽  
Trauma Patients ◽  
Shock Reversal ◽  
Organ Specific ◽  
Lactate Levels ◽  
Endothelial Integrity

Abstract Introduction In hemorrhaging trauma patients, the endothelium is activated, resulting in excessive endothelial synthesis of von Willebrand Factor (vWF), which may enhance micro-thrombi formation, resulting in obstruction of the microcirculation and endothelial injury, aggravating bleeding, as well as contributing to organ failure. Under normal conditions, vWF is cleaved by the metalloprotease ADAMTS-13. After trauma, ADAMTS-13 levels are reduced. Objectives To assess whether recombinant human ADAMTS-13 inhibits endothelial injury and organ failure in a rat trauma-transfusion model. Methods Blood products were prepared from syngeneic rat blood according to blood bank standards. Polytrauma was induced in rats by crush injury to the intestines and liver and by fracture of the femur. The rats were hemorrhaged until a mean arterial pressure (MAP) of 40 mmHg was reached. Rats were randomized to receive transfusion of RBCs, FFPs, and platelets in a 1:1:1 ratio to achieve a MAP of 70 mmHg, with or without the addition of ADAMTS-13 (50 μg/kg). Blood samples were assessed for biochemistry and rotational thromboelastometry (ROTEM). Syndecan-1 and VE-cadherin levels were measured as a reflection of endothelial integrity. The amount of leakage of dextran-FITC from the vascular system to the parenchyma in lungs was quantified. To assess inflammation, IL-6 and IL-8 levels were determined. Organ damage was assessed by histopathology. Results All rats were severely shocked, with no significant differences in shock parameters between groups. Rats treated with ADAMTS-13 showed signs of a more effective shock reversal (higher blood pressure, lower lactate levels) compared to controls. Also, ROTEM parameters of clot formation in rats receiving ADAMTS-13 improved compared to controls, which was mainly platelet-dependent. Syndecan-1 levels relative to baseline trended to be lower in ADAMTS-13 treated rats compared to controls (107 vs 149%, p = 0.08). ADAMTS-13 reduced albuminuria (1.7 vs 4.4 g/L, p < 0.01) and organ-specific inflammation (pulmonary IL-6 243 vs 369 pg/mL, p = 0.08; splenic IL-6 253 vs 307, p = 0.03) compared to controls, but did not improve histopathological scores. Conclusions The use of ADAMTS-13 in a rat trauma-transfusion model improves parameters of shock, platelet-driven coagulation, endothelial damage, and organ inflammation. These results suggest that ADAMTS-13 is important in mediating outcome of trauma. Whether ADAMTS-13 can be used as a therapeutic adjunct to treat bleeding trauma patients remains to be determined.

Detection of viruses by electron microscopy: Increased sensitivity by direct micro-ultracentrifugation of samples

1987 ◽  
Vol 45 ◽  
pp. 908-909
Author(s):  
Alain R. Trudel ◽  
M. Trudel
Keyword(s):  
Electron Microscopy ◽  
Fold Increase ◽  
Observation Time ◽  
Clinical Samples ◽  
Maximum Speed ◽  
Viral Particles ◽  
Structural Details ◽  
Latex Spheres ◽  
Increased Sensitivity ◽  
Size Of Particles

AirfugeR (Beckman) direct ultracentrifugation of viral samples on electron microscopy grids offers a rapid way to concentrate viral particles or subunits and facilitate their detection and study. Using the A-100 fixed angle rotor (30°) with a K factor of 19 at maximum speed (95 000 rpm), samples up to 240 μl can be prepared for electron microscopy observation in a few minutes: observation time is decreased and structural details are highlighted. Using latex spheres to calculate the increase in sensitivity compared to the inverted drop procedure, we obtained a 10 to 40 fold increase in sensitivity depending on the size of particles. This technique also permits quantification of viral particles in samples if an aliquot is mixed with latex spheres of known concentration.Direct ultracentrifugation for electron microscopy can be performed on laboratory samples such as gradient or column fractions, infected cell supernatant, or on clinical samples such as urine, tears, cephalo-rachidian liquid, etc..

A Scanning Electron Microscopic Study of Pro-Vascular Cellular Morphology in Chaetophora Incressata

1985 ◽  
Vol 43 ◽  
pp. 638-639
Author(s):  
A. E. Hotchkiss ◽  
A. T. Hotchkiss ◽  
R. P. Apkarian
Keyword(s):  
Green Algae ◽  
Vascular Plants ◽  
Vascular System ◽  
Higher Plants ◽  
Wall Structure ◽  
Electron Microscopic ◽  
Physiological Processes ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Multicellular green algae may be an ancestral form of the vascular plants. These algae exhibit cell wall structure, chlorophyll pigmentation, and physiological processes similar to those of higher plants. The presence of a vascular system which provides water, minerals, and nutrients to remote tissues in higher plants was believed unnecessary for the algae. Among the green algae, the Chaetophorales are complex highly branched forms that might require some means of nutrient transport. The Chaetophorales do possess apical meristematic groups of cells that have growth orientations suggestive of stem and root positions. Branches of Chaetophora incressata were examined by the scanning electron microscope (SEM) for ultrastructural evidence of pro-vascular transport.

No effect of artificial gravity on lung function with exercise training during head-down bed rest

2015 ◽  
pp. 1-7
Author(s):  
Longxiang Su ◽  
Yinghua Guo ◽  
Yajuan Wang ◽  
Delong Wang ◽  
Changting Liu
Keyword(s):  
Lung Function ◽  
Pulse Rate ◽  
Vital Capacity ◽  
Pulmonary Ventilation ◽  
Bed Rest ◽  
Forced Expiratory Volume ◽  
Observation Time ◽  
Artificial Gravity ◽  
Postural Changes ◽  
Expiratory Flow

AbstractTo explore the effectiveness of microgravity simulated by head-down bed rest (HDBR) and artificial gravity (AG) with exercise on lung function. Twenty-four volunteers were randomly divided into control and exercise countermeasure (CM) groups for 96 h of 6° HDBR. Comparisons of pulse rate, pulse oxygen saturation (SpO2) and lung function were made between these two groups at 0, 24, 48, 72, 96 h. Compared with the sitting position, inspiratory capacity and respiratory reserve volume were significantly higher than before HDBR (0° position) (P&lt; 0.05). Vital capacity, expiratory reserve volume, forced vital capacity, forced expiratory volume in 1 s, forced inspiratory vital capacity, forced inspiratory volume in 1 s, forced expiratory flow at 25, 50 and 75%, maximal mid-expiratory flow and peak expiratory flow were all significantly lower than those before HDBR (P&lt; 0.05). Neither control nor CM groups showed significant differences in the pulse rate, SpO2, pulmonary volume and pulmonary ventilation function over the HDBR observation time. Postural changes can lead to variation in lung volume and ventilation function, but a HDBR model induced no changes in pulmonary function and therefore should not be used to study AG CMs.

Sign in / Sign up

Export Citation Format

Share Document