Formation Pattern Analysis of Spheroids Formed by a Droplet-Based Microfluidic System for Predicting the Aggressiveness of Tumor Cells

Examining tumor heterogeneity is essential for selecting an appropriate anticancer treatment for an individual. This study aimed to distinguish low- and high-aggressive tumor cells by analyzing the formation patterns of spheroids. The droplet-based microfluidic system was employed for the formation of each spheroid from four different subtypes of breast tumor cells. Additionally, heterotypic spheroids with T lymphocytes and cancer-associated fibroblasts (CAFs) were produced, and distinctions between low- and high-aggressive tumor cells were explored through the analysis of formation patterns using circularity, convexity, and cell distributions. In both homotypic spheroids and heterotypic spheroids with T lymphocytes, spheroids formed from low-aggressive tumor cells exhibited high circularity and convexity. On the other hand, spheroids formed from high-aggressive tumor cells had relatively low circularity and convexity. In the case of heterotypic spheroids with CAFs, circularity and convexity did not exhibit clear differences between low- and high-aggressive tumor cells, but distinct variations were observed in cell distributions. CAFs and low-aggressive tumor cells were evenly distributed, whereas the CAFs were predominantly located in the inner layer, and high-aggressive tumor cells were primarily located in the outer layer. This finding can offer valuable insights into predicting the aggressiveness of unknown tumor cells.

A Perforated Plate-Based Cell Showering Device for Uniform Cell Distribution over Various Culture Substrates

Cell distribution is one of the primary factors that can affect cell morphology and behaviors, as it determines cell-cell interactions. Despite the importance of cell distribution, the seeding process of in vitro cell culture still highly relies on the traditional method using manual pipetting. Because manual pipetting cannot ensure a uniform cell distribution and has the possibility of compromising experimental reproducibility, an accurate and systemic seeding method that enables uniform cell seeding over versatile culture substrates is required. Here, we developed a perforated plate-based cell seeding device called the CellShower, which enabled uniform cell seeding over a large area of cell culture substrates. The working principles of the CellShower are based on the laminar filling flow and capillary force in microfluidics, and the design of the CellShower was optimized with numerical simulations. The versatility of the CellShower in view of uniform cell seeding was demonstrated by applying it to various types of culture substrates from a conventional culture dish to culture substrates having nanotopography, porous structures, and 3D concave structures. The CellShower and its operating principles are expected to contribute to enhancing the accuracy and reproducibility of biological experiments.

Virtual Reality as Tool for Bioprinting Quality Inspection: A Proof of Principle

As virtual reality (VR) has drastically evolved over the past few years, the field of applications of VR flourished way beyond the gaming industry. While commercial VR solutions might be available, there is a need to develop a workflow for specific applications. Bioprinting represents such an example. Here, complex 3D data is generated and needs to be visualized in the context of quality control. We demonstrate that the transfer to a commercially available VR software is possible by introducing an optimized workflow. In the present work, we developed a workflow for the visualization of the critical quality attribute (cQA) cell distribution in bioprinted (extrusion-based) samples in VR. The cQA cell distribution is directly influenced by the pre-processing step mixing of cell material in the bioink. Magnetic Resonance Imaging (MRI) was used as an analytical tool to generate spatially resolved 2.5 and 3D data of the bioprinted objects. A sample with poor quality in respect of the cQA cell distribution was identified as its inhomogeneous cell distribution could be displayed spatially resolved in VR. The described workflow facilitates the usage of VR as a tool for quality inspection in the field of bioprinting and represents a powerful tool for visualization of complex 3D MRI data.

A Three-Dimensional Imaging Method for the Quantification and Localization of Dynamic Cell Tracking Posttransplantation

Cell transplantation has been proposed as a promising therapeutic strategy for curing the diseases requiring tissue repairing and functional restoration. A preclinical method to systematically evaluate the fates of donor cells in recipients, spatially and temporally, is demanded for judging therapeutic potentials for the particularly designed cell transplantation. Yet, the dynamic cell tracking methodology for tracing transplanted cells in vivo is still at its early phase. Here, we created a practical protocol for dynamically tracking cell via a three-dimensional (3D) technique which enabled us to localize, quantify, and overall evaluate the transplanted hepatocytes within a liver failure mouse model. First, the capacity of 3D bioluminescence imaging for quantifying transplanted hepatocytes was defined. Images obtained from the 3D bioluminescence imaging module were then combined with the CT scanner to reconstruct structure images of host mice. With those reconstructed images, precise locations of transplanted hepatocytes in the liver of the recipient were dynamically monitored. Immunohistochemistry staining of transplanted cells, and the serology assay of liver panel of the host mice were applied to verify the successful engraftment of donor cells in the host livers. Our protocol was practical for evaluating the engraftment efficiency of donor cells at their preclinical phases, which is also applicable as a referable standard for studying the fates of other transplanted cells, such as stem cell-derived cell types, during preclinical studies with cell transplantation therapy.

Distribution of Amniotic Stem Cells in Human Term Amnion Membrane

Amnion membrane studies related to miscarriage have been conducted in the field of obstetrics and gynecology. However, the distribution of stem cells within the amnion, and the differences in the properties of each type of stem cells are still not well understood. We address this gap in knowledge in the present study where we morphologically classified, the amnion membrane, and we clarified the distribution of stem cells here to identify functionally different amniotic membrane-derived stem cells. The amnion is composed of the chorion frondosum region [umbilical cord -adjacent amnion (area A) and the placenta-covered amnion surrounding the umbilical cord (area B)] as well as the reflected amnion (area C). We found that human amnion epithelial stem cells (HAEC) that strongly express stem cell markers were abundant in region A. In addition to having the surface markers TRA-1-60, Tra-1-81, SSEA4 and SSEA3, HAEC are OCT-3/4 positive and have alkalinephosphatase activity. Human amniotic mesenchymal stem cells (HAMC) expressed CD73, and were found in region A and B, the expression of BCRP which is related to isolate stem cells as called SP population cells. Other cells that expressed the undifferentiated transcription factors KLF-A, OCTA, Oct3/4, c-MYC, and Sox2 were diffusely distributed in region C. These data suggest that different types of stem cells exist each functional region. Thus, understanding the distribution of the subclasses of stem cells would allow for the efficient harvest of suitable HAE and HAM stem cells for disease.

ImmunoAIzer: A Deep Learning-Based Computational Framework to Characterize Cell Distribution and Gene Mutation in Tumor Microenvironment

Spatial distribution of tumor infiltrating lymphocytes (TILs) and cancer cells in the tumor microenvironment (TME) along with tumor gene mutation status are of vital importance to the guidance of cancer immunotherapy and prognoses. In this work, we developed a deep learning-based computational framework, termed ImmunoAIzer, which involves: (1) the implementation of a semi-supervised strategy to train a cellular biomarker distribution prediction network (CBDPN) to make predictions of spatial distributions of CD3, CD20, PanCK, and DAPI biomarkers in the tumor microenvironment with an accuracy of 90.4%; (2) using CBDPN to select tumor areas on hematoxylin and eosin (H&E) staining tissue slides and training a multilabel tumor gene mutation detection network (TGMDN), which can detect APC, KRAS, and TP53 mutations with area-under-the-curve (AUC) values of 0.76, 0.77, and 0.79. These findings suggest that ImmunoAIzer could provide comprehensive information of cell distribution and tumor gene mutation status of colon cancer patients efficiently and less costly; hence, it could serve as an effective auxiliary tool for the guidance of immunotherapy and prognoses. The method is also generalizable and has the potential to be extended for application to other types of cancers other than colon cancer.

Cell Seeding Process Experiment and Simulation on Three-Dimensional Polyhedron and Cross-Link Design Scaffolds

Cell attachment to a scaffold is a significant step toward successful tissue engineering. Cell seeding is the first stage of cell attachment, and its efficiency and distribution can affect the final biological performance of the scaffold. One of the contributing factors to maximize cell seeding efficiency and consequently cell attachment is the design of the scaffold. In this study, we investigated the optimum scaffold structure using two designs – truncated octahedron (TO) structure and cubic structure – for cell attachment. A simulation approach, by ANSYS Fluent coupling the volume of fluid (VOF) model, discrete phase model (DPM), and cell impingement model (CIM), was developed for cell seeding process in scaffold, and the results were validated with in vitro cell culture assays. Our observations suggest that both designs showed a gradual lateral variation of attached cells, and live cell movements are extremely slow by diffusion only while dead cells cannot move without external force. The simulation approaches supply a more accurate model to simulate cell adhesion for three-dimensional structures. As the initial stages of cell attachment in vivo are hard to observe, this novel method provides an opportunity to predict cell distribution, thereby helping to optimize scaffold structures. As tissue formation is highly related to cell distribution, this model may help researchers predict the effect of applied scaffold and reduce the number of animal testing.

Intravenous Administration of Bone Marrow-Derived Mesenchymal Stem Cell, but not Adipose Tissue-Derived Stem Cell, Ameliorated the Neonatal Hypoxic-Ischemic Brain Injury by Changing Cerebral Inflammatory State in Rat

Perinatal hypoxic-ischemic (HI) brain injury occurs in 1 in 1,000 live births and remains the main cause of neurological disability and death in term infants. Cytotherapy has recently emerged as a novel treatment for tissue injury. In particular, mesenchymal stem cells (MSCs) are thought to have therapeutic potential, but little is known about the differences according to their origin. In the current study, we investigated the therapeutic effects and safety of intravenous injection of allogeneic bone marrow-derived MSCs (BM-MSCs) and adipose-derived stem cells (ADSCs) in a rat model of HI brain injury. HI models were generated by ligating the left carotid artery of postnatal day 7 Wistar/ST rats and exposing them to 8% hypoxia for 60 min. Bone marrow and adipose tissue were harvested from adult green fluorescent protein transgenic Wistar rats, and cells were isolated and cultured to develop BM-MSCs and ADSCs. At passaging stages 2–3, 1 × 10⁵ cells were intravenously injected into the external right jugular vein of the HI rats at 4 or 24 h after hypoxia. Brain damage was evaluated by counting the number of cells positive for active caspase-3 in the entire dentate gyrus. Microglial isotypes and serum cytokines/chemokines were also evaluated. Distribution of each cell type after intravenous injection was investigated pathologically and bio-optically by ex vivo imaging (IVIS®) with a fluorescent lipophilic tracer DiR. The mortality rate was higher in the ADSC group compared to the BM-MSC group, in pups injected with cells 4 h after hypoxia. The number of active caspase-3-positive cells significantly decreased in the BM-MSC group, and the percentage of M1 microglia (a proinflammatory isotype) was also lower in the BM-MSC vs control group in the penumbra of the cortex. Moreover, BM-MSC administration increased anti-inflammatory cytokine and growth factor levels, while ADSCs did not. Each injected cell type was mainly distributed in the lungs and liver, but ADSCs remained in the lungs longer. Pathologically, pulmonary embolisms and diffuse alveolar hemorrhages were seen in the ADSC group. These results indicated that injection of allogeneic BM-MSCs ameliorated neonatal HI brain injury, whereas ADSCs induced severe lung hemorrhage and higher mortality.

Distribution changes of interstitial cells of Cajal during cholesterol gallstone formation in guinea pigs fed a high cholesterol diet

BACKGROUND

Cholesterol gallstone is commonly observed in patients with gallbladder disorders. Interstitial cells of Cajal (ICCs) in the gallbladder are important for regulating gallbladder motility and have a close relationship with cholelithiasis.

AIM

The aim of this study was to explore changes in the distribution of gallbladder ICCs during cholesterol gallstone formation.

MATERIALS AND METHODS

Thirty guinea pigs were randomly divided into three groups: the control group and study groups. Animals in study groups were fed on high cholesterol diet for 4 weeks or 8 weeks. Animals in the control groups were fed on a standard diet for 8 weeks. Immunohistochemistry was performed to observe the shape, size, morphology, and numbers of ICCs from the neck of the gallbladder to the fundus of the gallbladder, and terminal deoxynucleotidyl transferase dUTP nick-end labeling was performed to detect apoptosis in ICCs from the upper part of the gallbladder to the lower part of the gallbladder.

RESULTS

There were no differences in the shape, size, and morphology of the gallbladder ICCs in all groups. Cholesterol gallstones formed in guinea pigs fed on high cholesterol diet. The numbers of gallbladder ICCs were significantly decreased from the neck of the gallbladder to the fundus of the gallbladder, and gallbladder ICC apoptosis was significantly increased from the upper part of the gallbladder to the lower part of the gallbladder in both guinea pigs fed on high cholesterol diet (all P<0.05).

CONCLUSION

Cholesterol gallstone formation reduced the density of gallbladder ICCs and increased the frequency of apoptotic gallbladder ICCs from the neck of the gallbladder to the fundus of the gallbladder, and these alterations may affect gallbladder ICC function.

Influence of cell distribution and diabetes status on the association between mitochondrial DNA copy number and aging phenotypes in the InCHIANTI study

Mitochondrial DNA copy number (mtDNA-CN) estimated in whole blood is a novel marker of mitochondrial mass and function that can be used in large population-based studies. Analyses that attempt to relate mtDNA-CN to specific aging phenotypes may be confounded by differences in the distribution of blood cell types across samples. Also, low or high mtDNA-CN may have a different meaning given the presence of diseases associated with mitochondrial damage. We evaluated the impact of blood cell type distribution and diabetes status on the association between mtDNA-CN and aging phenotypes, namely chronologic age, interleukin-6, hemoglobin, and all-cause mortality, among 672 participants of the InCHIANTI study. After accounting for white blood cell count, platelet count, and white blood cell proportions in multivariate models, associations of mtDNA-CN with age and interleukin-6 were no longer statistically significant. Evaluation of a statistical interaction by diabetes status suggested heterogeneity of effects in the analysis of mortality (P < 0.01). The magnitude and direction of associations between mtDNA-CN estimated from blood samples and aging phenotypes are influenced by the sample cell type distribution and disease status. Therefore, accounting for these factors may aid understanding of the relevance of mitochondrial DNA copy number to health and aging.

The Process of Engraftment of Myogenic Cells in Skeletal Muscles of Primates: Understanding Clinical Observations and Setting Directions in Cell Transplantation Research

We studied in macaques the evolution of the intramuscular transplantation of muscle precursor cells between the time of administration and the time at which the graft is considered stable. Satellite cell–derived myoblasts labeled with ß-galactosidase were transplanted into 1 cm³ muscle regions following cell culture and transplantation protocols similar to our last clinical trials. These regions were biopsied 1 h, 1, 3, 7 d, and 3 wk later and analyzed by histology. We observed that the cell suspension leaks from the muscle bundles during injection toward the epimysium and perimysium, where most cells accumulate after transplantation. We observed evidence of necrosis, apoptosis, and mitosis in the accumulations of grafted cells, and of potential migration to participate in myofiber regeneration in the surrounding muscle bundles. After 3 wk, the compact accumulations of grafted cells left only some graft-derived myotubes and small myofibers in the perimysium. Hybrid myofibers were abundant in the muscle fascicles at 3 wk posttransplantation, and they most likely occur by grafted myoblasts that migrated from the peripheral accumulations than by the few remaining within the fascicles immediately after injection. These observations explain the findings in clinical trials of myoblast transplantation and provide information for the future research in cell therapy in myology.

Improvement of Distribution and Osteogenic Differentiation of Human Mesenchymal Stem Cells by Hyaluronic Acid and β-Tricalcium Phosphate-Coated Polymeric Scaffold In Vitro

Bone tissue engineering requires a well-designed scaffold that can be biodegradable, biocompatible, and support the stem cells to osteogenic differentiation. Porous polycaprolactone (PCL) scaffold prepared by fused deposition modeling is an attractive biomaterial that has been used in clinic. However, PCL scaffolds lack biological function and osteoinductivity. In this study, we functionalized the PCL scaffolds by embedding them with a matrix of hyaluronic acid/β-tricalcium phosphate (HA/TCP). Human mesenchymal stem cells (MSCs) were cultured on scaffolds with and without coating to investigate proliferation and osteogenic differentiation. The DNA amount was significantly higher in the HA/TCP-coated scaffold on day 21. At the gene expression level, HA/TCP coating significantly increased the expression of ALP and COLI on day 4. These data correlated with the ALP activity peaking on day 7 in the HA/TCP-coated scaffold. Scanning electron microscope and histological analysis revealed that the cell matrix and calcium deposition were distributed more uniformly in the coated scaffolds compared to scaffolds without coating. In conclusion, the HA/TCP coating improved cellular proliferation, osteogenic differentiation, and uniform distribution of the cellular matrix in vitro. The HA/TCP-PCL scaffold holds great promise to accommodate human bone marrow-derived MSCs for bone reconstruction purposes, which warrants future in vivo studies.

RipleyGUI: software for analyzing spatial patterns in 3D cell distributions

The true revolution in the age of digital neuroanatomy is the ability to extensively quantify anatomical structures and thus investigate structure-function relationships in great detail. To facilitate the quantification of neuronal cell patterns we have developed RipleyGUI, a MATLAB-based software that can be used to detect patterns in the 3D distribution of cells. RipleyGUI uses Ripley's K-function to analyze spatial distributions. In addition the software contains statistical tools to determine quantitative statistical differences, and tools for spatial transformations that are useful for analyzing non-stationary point patterns. The software has a graphical user interface making it easy to use without programming experience, and an extensive user manual explaining the basic concepts underlying the different statistical tools used to analyze spatial point patterns. The described analysis tool can be used for determining the spatial organization of neurons that is important for a detailed study of structure-function relationships. For example, neocortex that can be subdivided into six layers based on cell density and cell types can also be analyzed in terms of organizational principles distinguishing the layers.

Magnetic Nanoparticles to Enhance Cell Seeding and Distribution in Tissue Engineering Scaffolds

The success of tissue engineering scaffolds is intimately linked with the ability of the seeded cells to adequately distribute and proliferate within the scaffold matrix. In tissue engineering scaffolds, it is difficult to achieve adequate distribution due to the hydrophobic nature of most scaffold materials and poor initial distribution following scaffold seeding. In this study, we investigated the distribution of cells in PLGA salt-leached scaffolds after seeding with magnetic nanoparticle loaded cells with a neodymium magnet placed below. The combined use of magnetic nanoparticle seeded cells and magnetic force was able to not only increase the total number of scaffold adherent cells, but also increase the infiltration and distribution compared with controls. This method to control the distribution of cells may provide a method to increase the functionality of tissue engineering scaffolds.

Initial motor axon outgrowth from the developing central nervous system

Rat and chick studies show that the earliest motor rootlet axon bundles emerge from all levels of the neural tube between radial glial end feet which comprise the presumptive glia limitans. The loose arrangement of the end feet at the time of emergence facilitates this passage. The points of emergence are regularly spaced in relation to the long axis of the neural tube and are not defined by any cell contact with its surface. Each rootlet carries a covering of basal lamina from the neural tube surface, which forms a sleeve around it. It is only after bundles of ventral rootlet axons have emerged that cells associate with them, forming clusters on the rootlet surface at a distance peripheral to the CNS surface of both species. A tight collar of glial end feet develops around the axon bundle at the neural tube surface shortly after initial emergence. These arrangements are in sharp contrast to those seen in the sensory rootlets, where clusters of boundary cap cells prefigure the sensory entry zones at the attachments of the prospective dorsal spinal and cranial sensory rootlets. Boundary cap cells resemble cluster cells and a neural crest origin seems the most likely for them. The study clearly demonstrates that no features resembling boundary caps are found in relation to the developing motor exit points.