scholarly journals Experimental and numerical investigations of fluid flow in bioreactors for optimized in vitro stem cell loading in xenografts

2018 ◽  
Vol 4 (1) ◽  
pp. 423-427
Author(s):  
Robert Ott ◽  
Carolin Wüstenhagen ◽  
Michael Stiehm ◽  
Klaus-Peter Schmitz ◽  
Stefan Siewert ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cfd Simulation ◽  
Healing Process ◽  
Three Dimensional ◽  
Flow Conditions ◽  
Micro Computed Tomography ◽  
3D Scaffold ◽  
Numerical Investigations

AbstractIn tissue engineering and regenerative medicine mesenchymal stem cells (MSC) are widely used to replace and restore the function of dysfunctional or missing tissue. Recent studies have shown significant enhancements of the in vivo healing process following dentofacial bone augmentation procedures employing stem cell-loaded xenografts. We conducted experimental and numerical investigations in perfusion flow bioreactor-xenograft-systems to identify flow conditions as well as bioreactor design features that allow for homogeneous MSC-distribution in Geistlich Bio- Oss Block xenografts. Pressure gradient - velocity characteristics and flow distributions were investigated experimentally and numerically for two bioreactor designs at steady-state flow conditions with Reynolds numbers (Re) ranging from 0.01 ≤ Re ≤ 0.32. Distilled water at 20°C with a dynamic viscosity of 1.002 mPa∙s and a density of 998 kg/m3 was used. The geometry of the xenograft utilized in three-dimensional computational fluid dynamics (CFD) simulation was obtained by means of micro-computed tomography (μCT) at an isotropic spatial resolution of 9.5 μm. The permeability values calculated from the experimental data are in good accordance with the numerical results. The investigations showed that the increase of the inflow- and outflow-area diameter, as well as the decrease of the volumetric flow rate, result in a decreasing heterogeneity of the flow distribution within the xenograft. The calculated wall shear stress rates in the three-dimensional (3D) scaffold range from 1∙10-12Pa ≤ τ ≤ 0.2 Pa. Experimentally validated CFD simulations introduced in this study provide an applicable tool to assess optimal flow conditions for homogeneous MSC distribution in bioreactor-xenograft-systems.

scholarly journals Experimental and numerical investigations of fluid flow for optimized in vitro stem cell loading in xenografts

2017 ◽  
Vol 3 (2) ◽  
pp. 799-802
Author(s):  
Robert Ott ◽  
Carolin Wüstenhagen ◽  
Heiner Martin ◽  
Michael Stiehm ◽  
Wolfram Schmidt ◽  
...  
Keyword(s):  
Stem Cell ◽  
Fluid Flow ◽  
Pressure Gradient ◽  
Cfd Simulation ◽  
Reynolds Numbers ◽  
Distribution Analysis ◽  
Cell Distribution ◽  
Flow Conditions ◽  
Micro Computed Tomography ◽  
Numerical Investigations

AbstractIn dentofacial surgery, augmentation procedures employing xenografts have become a reliable treatment. Recent studies, however, have shown significant enhance-ments of the in vivo bone tissue augmentation using mesenchymal stem cells loaded into bone grafts. We conducted experimental and numerical investigations in flow perfusion systems to determine flow conditions which allow for homogenous stem cell distribution in BioOss Block (Geistlich Pharma AG, Switzerland) xenografts. Pressure gradient-velocity characteristics and flow distributions were investigated experimentally and numerically at steady state flow conditions with Reynolds numbers (Re) ranging from 0.01 ≤ Re ≤ 0.40. Distilled water at 20°C with a dynamic viscosity of 1.002 mPa.s and a density of 998 kg/m3 was used. The geometry utilized in three-dimensional computa-tional fluid dynamics (CFD) simulation was obtained by means of micro-computed tomography (μCT). Results of CFD analysis are in good accordance with experimental data. The comparison of the pressure gradient-velocity characteris-tics for experimental and numerical data yields a relative error of 3.6%. According to Darcy’s law for creeping fluid flow the experimentally determined permeability is 2.55.10-9 m2. Moreover, numerical flow distribution analysis shows an increasingly heterogenic streamline distribution for increasing Reynolds numbers. Experimentally validated CFD simulations introduced in this study provide a tool to assess optimal flow conditions for a homogenous stem cell distribution in perfusion flow systems.

scholarly journals A 3D In Vitro Model for Burn Wounds: Monitoring of Regeneration on the Epidermal Level

Biomedicines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1153
Author(s):  
Verena Schneider ◽  
Daniel Kruse ◽  
Ives Bernardelli de Mattos ◽  
Saskia Zöphel ◽  
Kendra-Kathrin Tiltmann ◽  
...  
Keyword(s):  
Wound Healing ◽  
Inflammatory Response ◽  
Healing Process ◽  
Three Dimensional ◽  
Source Model ◽  
Burn Wound ◽  
Thermal Burn ◽  
Burn Wounds

Burns affect millions every year and a model to mimic the pathophysiology of such injuries in detail is required to better understand regeneration. The current gold standard for studying burn wounds are animal models, which are under criticism due to ethical considerations and a limited predictiveness. Here, we present a three-dimensional burn model, based on an open-source model, to monitor wound healing on the epidermal level. Skin equivalents were burned, using a preheated metal cylinder. The healing process was monitored regarding histomorphology, metabolic changes, inflammatory response and reepithelialization for 14 days. During this time, the wound size decreased from 25% to 5% of the model area and the inflammatory response (IL-1β, IL-6 and IL-8) showed a comparable course to wounding and healing in vivo. Additionally, the topical application of 5% dexpanthenol enhanced tissue morphology and the number of proliferative keratinocytes in the newly formed epidermis, but did not influence the overall reepithelialization rate. In summary, the model showed a comparable healing process to in vivo, and thus, offers the opportunity to better understand the physiology of thermal burn wound healing on the keratinocyte level.

scholarly journals Engineered Heterochronic Parabiosis in 3D Microphysiological System for Identification of Muscle Rejuvenating Factors

2020 ◽  
Author(s):  
Yunki Lee ◽  
Jeongmoon J. Choi ◽  
Song Ih Ahn ◽  
Nan Hee Leea ◽  
Woojin M. Han ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell Function ◽  
Three Dimensional ◽  
Muscle Stem Cell ◽  
Organ Systems ◽  
Systemic Factors ◽  
Underlying Mechanisms ◽  
On Chip

AbstractExposure of aged mice to a young systemic milieu revealed remarkable rejuvenation effects on aged tissues, including skeletal muscle. Although some candidate factors have been identified, the exact identity and the underlying mechanisms of putative rejuvenating factors remain elusive, mainly due to the complexity of in vivo parabiosis. Here, we present an in vitro muscle parabiosis system that integrates young- and old-muscle stem cell vascular niche on a three-dimensional microfluidic platform designed to recapitulate key features of native muscle stem cell microenvironment. This innovative system enables mechanistic studies of cellular dynamics and molecular interactions within the muscle stem cell niche, especially in response to conditional extrinsic stimuli of local and systemic factors. We demonstrate that vascular endothelial growth factor (VEGF) signaling from endothelial cells and myotubes synergistically contribute to the rejuvenation of the aged muscle stem cell function. Moreover, with the adjustable on-chip system, we can mimic both blood transfusion and parabiosis and detect the time-varying effects of anti-geronic and pro-geronic factors in a single organ or multi-organ systems. Our unique approach presents a complementary in vitro model to supplement in vivo parabiosis for identifying potential anti-geronic factors responsible for revitalizing aging organs.

scholarly journals PEG-modified gadolinium nanoparticles as contrast agents for in vivo micro-CT

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charmainne Cruje ◽  
P. Joy Dunmore-Buyze ◽  
Eric Grolman ◽  
David W. Holdsworth ◽  
Elizabeth R. Gillies ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Soft Tissues ◽  
Three Dimensional ◽  
Blood Pool ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Poly Ethylene

AbstractVascular research is largely performed in rodents with the goal of developing treatments for human disease. Micro-computed tomography (micro-CT) provides non-destructive three-dimensional imaging that can be used to study the vasculature of rodents. However, to distinguish vasculature from other soft tissues, long-circulating contrast agents are required. In this study, we demonstrated that poly(ethylene glycol) (PEG)-coated gadolinium nanoparticles can be used as a vascular contrast agent in micro-CT. The coated particles could be lyophilized and then redispersed in an aqueous solution to achieve 100 mg/mL of gadolinium. After an intravenous injection of the contrast agent into mice, micro-CT scans showed blood pool contrast enhancements of at least 200 HU for 30 min. Imaging and quantitative analysis of gadolinium in tissues showed the presence of contrast agent in clearance organs including the liver and spleen and very low amounts in other organs. In vitro cell culture experiments, subcutaneous injections, and analysis of mouse body weight suggested that the agents exhibited low toxicity. Histological analysis of tissues 5 days after injection of the contrast agent showed cytotoxicity in the spleen, but no abnormalities were observed in the liver, lungs, kidneys, and bladder.

scholarly journals Mesenchymal-like glioma cells are enriched in the gelatin methacrylate hydrogels

2021 ◽  
Author(s):  
Nameeta Shah ◽  
Pavan M. Hallur ◽  
Raksha A. Ganesh ◽  
Pranali Sonpatki ◽  
Divya Naik ◽  
...  
Keyword(s):  
Therapeutic Response ◽  
Immune Cell ◽  
Three Dimensional ◽  
Glioma Cells ◽  
Cellular Phenotype ◽  
3D Scaffold ◽  
Promising Alternative ◽  
Cells Cultured

AbstractGlioblastoma is the most lethal primary malignant brain tumor in adults. Simplified two-dimensional (2D) cell culture and neurospheres in vitro models fail to recapitulate the complexity of the tumor microenvironment, limiting its ability to predict therapeutic response. Three-dimensional (3D) scaffold-based models have emerged as a promising alternative for addressing these concerns. One such 3D system is gelatin methacrylate (GelMA) hydrogels, which can be used for modeling the glioblastoma microenvironment. We characterized the phenotype of patient-derived glioma cells cultured in GelMA hydrogels (3D-GMH) for their tumorigenic properties using invasion and chemoresponse assays. In addition, we used integrated single-cell and spatial transcriptome analysis to compare cells cultured in 3D-GMH to cells in vivo. Finally, we assessed tumor-immune cell interactions with a macrophage infiltration assay and a cytokine array. We show that cells cultured in 3D-GMH develop a mesenchymal-like cellular phenotype found in perivascular and hypoxic regions present in the core of the tumor, and recruit macrophages by secreting cytokines in contrast to the cells grown as neurospheres that match the phenotype of cells of the infiltrative edge of the tumor.

scholarly journals A Three-Dimensional Co-Culture Model for Rheumatoid Arthritis Pannus Tissue

2021 ◽  
Vol 9 ◽  
Author(s):  
Jietao Lin ◽  
Antonia RuJia Sun ◽  
Jian Li ◽  
Tianying Yuan ◽  
Wenxiang Cheng ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Vascular Endothelial Cells ◽  
Three Dimensional ◽  
Synovial Fibroblasts ◽  
Vascular Endothelial ◽  
3D Scaffold ◽  
Culture Model ◽  
Pannus Tissue

Three-dimensional (3D) co-culture models have closer physiological cell composition and behavior than traditional 2D culture. They exhibit pharmacological effects like in vivo responses, and therefore serve as a high-throughput drug screening model to evaluate drug efficacy and safety in vitro. In this study, we created a 3D co-culture environment to mimic pathological characteristics of rheumatoid arthritis (RA) pannus tissue. 3D scaffold was constructed by bioprinting technology with synovial fibroblasts (MH7A), vascular endothelial cells (EA.hy 926) and gelatin/alginate hydrogels. Cell viability was observed during 7-day culture and the proliferation rate of co-culture cells showed a stable increase stage. Cell-cell interactions were evaluated in the 3D printed scaffold and we found that spheroid size increased with time. TNF-α stimulated MH7A and EA.hy 926 in 3D pannus model showed higher vascular endothelial growth factor (VEGF) and angiopoietin (ANG) protein expression over time. For drug validation, methotrexate (MTX) was used to examine inhibition effects of angiogenesis in 3D pannus co-culture model. In conclusion, this 3D co-culture pannus model with biological characteristics may help the development of anti-RA drug research.

scholarly journals Sex-dependent differences in central artery haemodynamics in normal and fibulin-5 deficient mice: implications for ageing

2019 ◽  
Vol 475 (2221) ◽  
pp. 20180076 ◽  
Author(s):  
Federica Cuomo ◽  
Jacopo Ferruzzi ◽  
Pradyumn Agarwal ◽  
Chen Li ◽  
Zhen W. Zhuang ◽  
...  
Keyword(s):  
Computational Models ◽  
Pulse Wave ◽  
Three Dimensional ◽  
Micro Computed Tomography ◽  
Central Artery ◽  
Wall Stiffness ◽  
Outflow Boundary ◽  
Deficient Mice

Mouse models provide unique opportunities to study vascular disease, but they demand increased experimental and computational resolution. We describe a workflow for combining in vivo and in vitro biomechanical data to build mouse-specific computational models of the central vasculature including regional variations in biaxial wall stiffness, thickness and perivascular support. These fluid–solid interaction models are informed by micro-computed tomography imaging and in vivo ultrasound and pressure measurements, and include mouse-specific inflow and outflow boundary conditions. Hence, the model can capture three-dimensional unsteady flows and pulse wave characteristics. The utility of this experimental–computational approach is illustrated by comparing central artery biomechanics in adult wild-type and fibulin-5 deficient mice, a model of early vascular ageing. Findings are also examined as a function of sex. Computational results compare well with measurements and data available in the literature and suggest that pulse wave velocity, a spatially integrated measure of arterial stiffness, does not reflect well the presence of regional differences in stiffening, particularly those manifested in male versus female mice. Modelling results are also useful for comparing quantities that are difficult to measure or infer experimentally, including local pulse pressures at the renal arteries and characteristics of the peripheral vascular bed that may differ with disease.

scholarly journals Gelatin methacrylate hydrogels culture model for glioblastoma cells enriches for mesenchymal-like state and models interactions with immune cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nameeta Shah ◽  
Pavan M. Hallur ◽  
Raksha A. Ganesh ◽  
Pranali Sonpatki ◽  
Divya Naik ◽  
...  
Keyword(s):  
Immune Cell ◽  
Three Dimensional ◽  
Glioma Cells ◽  
Glioblastoma Cells ◽  
Treatment Resistant ◽  
3D Scaffold ◽  
Promising Alternative ◽  
Cells Cultured

AbstractGlioblastoma is the most lethal primary malignant brain tumor in adults. Simplified two-dimensional (2D) cell culture and neurospheres in vitro models fail to recapitulate the complexity of the tumor microenvironment, limiting its ability to predict therapeutic response. Three-dimensional (3D) scaffold-based models have emerged as a promising alternative for addressing these concerns. One such 3D system is gelatin methacrylate (GelMA) hydrogels, and we aimed to understand the suitability of using this system to mimic treatment-resistant glioblastoma cells that reside in specific niches. We characterized the phenotype of patient-derived glioma cells cultured in GelMA hydrogels (3D-GMH) for their tumorigenic properties using invasion and chemoresponse assays. In addition, we used integrated single-cell and spatial transcriptome analysis to compare cells cultured in 3D-GMH to neoplastic cells in vivo. Finally, we assessed tumor-immune cell interactions with a macrophage infiltration assay and a cytokine array. We show that the 3D-GMH system enriches treatment-resistant mesenchymal cells that are not represented in neurosphere cultures. Cells cultured in 3D-GMH resemble a mesenchymal-like cellular phenotype found in perivascular and hypoxic regions and recruit macrophages by secreting cytokines, a hallmark of the mesenchymal phenotype. Our 3D-GMH model effectively mimics the phenotype of glioma cells that are found in the perivascular and hypoxic niches of the glioblastoma core in situ, in contrast to the neurosphere cultures that enrich cells of the infiltrative edge of the tumor. This contrast highlights the need for due diligence in selecting an appropriate model when designing a study‘s objectives.

scholarly journals The Application of Mesenchymal Stem Cells on Wound Repair and Regeneration

2021 ◽  
Vol 11 (7) ◽  
pp. 3000
Author(s):  
Bruna Lopes ◽  
Patrícia Sousa ◽  
Rui Alvites ◽  
Mariana Branquinho ◽  
Ana Sousa ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Wound Repair ◽  
Three Dimensional ◽  
Skin Lesions ◽  
Skin Regeneration ◽  
Cell Therapies ◽  
Cell Sources

In the past decades, regenerative medicine applied on skin lesions has been a field of constant improvement for both human and veterinary medicine. The process of healing cutaneous wound injuries implicates a well-organized cascade of molecular and biological processes. However, sometimes the normal process fails and can result in a chronic lesion. In addition, wounds are considered an increasing clinical impairment, due to the progressive ageing of the population, as well as the prevalence of concomitant diseases, such as diabetes and obesity, that represent risk-aggravating factors for the development of chronic skin lesions. Stem cells’ regenerative potential has been recognized worldwide, including towards skin lesion repair, Tissue engineering techniques have long been successfully associated with stem cell therapies, namely the application of three-dimensional (3D) bioprinted scaffolds. With this review, we intend to explore several stem cell sources with promising aptitude towards skin regeneration, as well as different techniques used to deliver those cells and provide a supporting extracellular matrix environment, with effective outcomes. Furthermore, different studies are discussed, both in vitro and in vivo, in terms of their relevance in the skin regeneration field.

scholarly journals Ultra-Thin Porous PDLLA Films Promote Generation, Maintenance, and Viability of Stem Cell Spheroids

2021 ◽  
Vol 9 ◽  
Author(s):  
Ya An Tsai ◽  
Tianshu Li ◽  
Lucia A. Torres-Fernández ◽  
Stefan C. Weise ◽  
Waldemar Kolanus ◽  
...  
Keyword(s):  
Stem Cell ◽  
Scale Up ◽  
Three Dimensional ◽  
3D Culture ◽  
Division Rate ◽  
Average Pore ◽  
Simple Method ◽  
Coating Method

Three-dimensional (3D) culture bridges and minimizes the gap between in vitro and in vivo states of cells and various 3D culture systems have been developed according to different approaches. However, most of these approaches are either complicated to operate, or costive to scale up. Therefore, a simple method for stem cell spheroid formation and preservation was proposed using poly(D,L-lactic acid) porous thin film (porous nanosheet), which were fabricated by a roll-to-roll gravure coating method combining a solvent etching process. The obtained porous nanosheet was less than 200 nm in thickness and had an average pore area of 6.6 μm2 with a porosity of 0.887. It offered a semi-adhesive surface for stem cells to form spheroids and maintained the average spheroid diameter below 100 μm for 5 days. In comparison to the spheroids formed in suspension culture, the porous nanosheets improved cell viability and cell division rate, suggesting the better feasibility to be applied as 3D culture scaffolds.

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