RESUMEN

INTRODUCTION: Pancreatic ductal adenocarcinoma presents with a dismal prognosis. Personalized therapy is urgently warranted to overcome the treatment limitations of the 'one-size-fits-all' scheme. Organoids have emerged as fundamental novel tools to study tumor biology and heterogeneity, hence overcoming limitations of other model systems by better-reflecting tissue heterogeneity and recapitulating in-vivo processes. Besides their crucial role in basic research, they have evolved as tools for translational drug discovery and patient stratification. AREAS COVERED: This review highlights the achievements of an organoid-based drug investigation and discovery. The authors present an overview of studies using organoids for drug testing. Further, they pinpoint studies correlating the in vitro prediction of organoids to the actual patient`s response. Furthermore, the authors describe novel model systems and take a thorough overlook of microfluidic chips, synthetic matrices, multicellular systems, bioprinting, and stem cell-derived pancreatic organoid systems. EXPERT OPINION: Organoid systems promise great potential for future clinical applications. Indeed, they may be implemented into informed decision-making for guiding therapies. However, validation by randomized trials is mandatory. Additionally, organoids in combination with other cellular compartments may be exploited for drug discovery by studying niche-tumor interaction. Yet, several precautions must be kept in mind, such as standardization and reproducibility.

Asunto(s)

RESUMEN

Myocardium consists of cardiac cells that interact with their environment through physical, biochemical, and electrical stimulations. The physiology, function, and metabolism of cardiac tissue are affected by this dynamic structure. Within the myocardium, cardiomyocytes' orientations are parallel, creating a dominant orientation. Additionally, local alignments of fibers, along with a helical organization, become evident at the macroscopic level. For the successful development of a reliable in vitro cardiac model, evaluation of cardiac cells' behavior in a dynamic microenvironment, as well as their spatial architecture, is mandatory. In this study, we hypothesize that complex interactions between long-term contraction boundary conditions and cyclic mechanical stimulation may provide a physiological mechanism to generate off-axis alignments in the preferred mechanical stretch direction. This off-axis alignment can be engineered in vitro and, most importantly, mirrors the helical arrangements observed in vivo. For this purpose, uniaxial mechanical stretching of dECM-fibrin hydrogels was performed on pre-aligned 3D cultures of cardiac cells. In view of the potential development of helical structures similar to those in native hearts, the possibility of generating oblique alignments ranging between 0° and 90° was explored. Indeed, our investigations of cell alignment in 3D, employing both mechanical stimulation and groove constraint, provide a reliable mechanism for the generation of helicoidal structures in the myocardium. By combining cyclic stretch and geometric alignment in grooves, an intermediate angle toward favored direction can be achieved experimentally: while cyclic stretch produces a perpendicular orientation, geometric alignment is associated with a parallel one. In our 2D and 3D culture conditions, nonlinear cellular addition of the strains and strain avoidance concept reliably predicted the preferred cellular alignment. The 3D dECM-fibrin model system in this study shows that cyclical stretching supports cell survival and development. Using mechanical stimulation of pre-aligned heart cells, maturation markers are augmented in neonatal cardiomyocytes, while the beating culture period is prolonged, indicating an improved model function. We propose a simplified theoretical model based on numerical simulation and nonlinear strain avoidance by cells to explain oblique alignment angles. Thus, this work lays a possible rational basis for understanding and engineering oblique cellular alignments, such as the helicoidal layout of the heart, using approaches that simultaneously enhance maturation and function.

RESUMEN

Cardiomyocyte alignment in myocardium tissue plays a significant role in the physiological, electrical, and mechanical functions of the myocardium. It remains, however, difficult to align cardiac cells in a 3D in vitro heart model. This paper proposes a simple method to align cells using microfabricated Polydimethylsiloxane (PDMS) grooves with large dimensions (of up to 350 µm in width), similar to the dimensions of trabeculae carneae, the smallest functional unit of the myocardium. Two cell groups were used in this work; first, H9c2 cells in combination with Nor10 cells for proof of concept, and second, neonatal cardiac cells to investigate the functionality of the 3D model. This model compared the patterned and nonpatterned 3D constructs, as well as the 2D cell cultures, with and without patterns. In addition to alignment, we assessed the functionality of our proposed 3D model by comparing beating rates between aligned and non-aligned structures. In order to assess the practicality of the model, the 3D aligned structures should be demonstrated to be detachable and alignable. This evaluation is crucial to the use of this 3D functional model in future studies related to drug screening, building blocks for tissue engineering, and as a heart-on-chip by integrating microfluidics.

Asunto(s)

RESUMEN

Biochemical and biophysical properties instruct cardiac tissue morphogenesis. Here, we are reporting on a blend of cardiac decellularized extracellular matrix (dECM) from porcine ventricular tissue and fibrinogen that is suitable for investigations employing an in vitro 3D cardiac cell culture model. Rapid and specific coagulation with thrombin facilitates the gentle inclusion of cells while avoiding sedimentation during formation of the dECM-fibrin composite. Our investigations revealed enhanced cardiogenic differentiation in the H9c2 myoblast cells when using the system in a co-culture with Nor-10 fibroblasts. Further enhancement of differentiation efficiency was achieved by 3D embedding of rat neonatal cardiomyocytes in the 3D system. Calcium imaging and analysis of beating motion both indicate that the dECM-fibrin composite significantly enhances recovery, frequency, synchrony, and the maintenance of spontaneous beating, as compared to various controls including Matrigel, pure fibrin and collagen I as well as a fibrin-collagen I blend.

Asunto(s)

RESUMEN

Standardised and high-throughput methods have been developed for the production and experimental handling of some 3D in vitro models. However, adapted analytical tools are still missing for scientists and researchers to fully exploit the potential of complex cellular models in pre-clinical drug testing and precision medicine. Histology is the established, cost-effective and gold standard method for structural and functional tissue analysis. However, standard histological processes are challenging and costly to apply to 3D cell models, as their small size often leads to poor alignment of samples, which lowers analysis throughput. This body of work proposes a new approach: HistoBrick facilitates histological processing of spheroids and organoids by enabling gel embedding of 3D cell models with precise coplanar alignment, parallel to the sectioning plane, thus minimising the loss of sample material. HistoBrick's features are compatible with automation standards, potentially allowing automated sample transfer from a multi-well plate to the gel device. Moreover, HistoBrick's technology was validated by demonstrating the alignment of HepG2 cultured spheroids measuring 150-200 µm in diameter with a height precision of ± 80 µm. HistoBrick allows up to 96 samples to be studied across minimal sections, paving the way towards high-throughput micro-histology.

Asunto(s)

RESUMEN

To some extent, cell therapy for myocardial infarction (MI) has supported the idea of cardiac repair; however, further optimizations are inevitable. Combined approaches that comprise suitable cell sources and supporting molecules considerably improved its effect. Here, we devised a strategy of simultaneous transplantation of human cardiac progenitor cells (CPCs) and an optimized oxygen generating microparticles (MPs) embedded in fibrin hydrogel, which was injected into a left anterior descending artery (LAD) ligating-based rat model of acute myocardial infarction (AMI). Functional parameters of the heart, particularly left ventricular systolic function, markedly improved and reached pre-AMI levels. This functional restoration was well correlated with substantially lower fibrotic tissue formation and greater vascular density in the infarct area. Our novel approach promoted CPCs retention and differentiation into cardiovascular lineages. We propose this novel co-transplantation strategy for more efficient cell therapy of AMI which may function by providing an oxygen-rich microenvironment, and thus regulate cell survival and differentiation.

Asunto(s)

RESUMEN

BACKGROUND: There are evidences showing the relation between chronic hypoxia and Alzheimer's disease (AD) as a metabolic neurodegenerative disease. This study was designed to evaluate the effects of chronic hypoxia on factors which characterized in AD to introduce a new model of AD-dementia. METHODS AND MATERIALS: Twenty-four male rats were randomly divided in three groups: Control group (Co), Sham group (Sh), Hypoxia induction group (Hx, exposed to hypoxic chamber [oxygen 8% and nitrogen 92%] for 30 days, 4 h/day). Spatial learning and memory were analyzed using the Morris water maze task. At day 30 after hypoxia period, animals were sacrificed and serum was gathered for pro-inflammatory cytokines (interleukin-1ß and tumor necrosis factor) measurements and brains were used for molecular and histopathological investigations. RESULTS: According to behavioral studies, a significant impairment was seen in Hx group (P < 0.05). TNF-α and IL-1ß showed a significant enhanced in Hx group comparing with Co group and Sh group (P < 0.05). As well, the gene expression of seladin-1, Tuj1 and the number of seladin-1+, Tuj1+neurons significantly decreased and also the mean number of dark neurons significantly increased in CA1 and CA3 regions of hippocampus. CONCLUSIONS: In this study, a new model of AD was developed which showed the underlying mechanisms of AD and its relations with chronic hypoxia. Hypoxia for 30 days decreased seladin-1, Tuj1 expression, increased the number of dark neurons, and also induced memory impairment. These results indicated that chronic hypoxia mediated the dementia underlying AD and AD-related pathogenesis in rat.

RESUMEN

A great number of people suffer from burning injuries all around the world each year. Applying an appropriate wound dressing can promote new tissue formation, prevent losing water and inhibit invasion of infectious organisms. In this study, egg white with a long standing history, as a homemade remedy, was fabricated as a wound dressing for burn injuries. For this reason, ovalbumin films were cross-linked by 1-ethyl-3-3-dimethyl aminopropyl carbodiimide hydrochloride (EDC) with different concentrations (1, 5 and 10mM) using three concentrations of ethanol. Physical-chemical characterizations including Fourier transform infrared spectroscopy (FTIR), gas transmission rate (GTR), tensile mechanical tests, water uptake and degradation rate were performed on the samples. The sample with 5mM crosslinking agent at 70% ethanol was considered as the optimized one with 417kPa of ultimate tensile strength, 64% elongation at break and 230% water uptake. In addition, biological evaluations conducted by MTT and live/dead assay indicated no sign of cyto-toxicity for all the samples. Moreover, scanning electron microscopy (SEM) showed that the fibroblast cells were well spread on the sample with the formation of filopodia. In conclusion, modified ovalbumin can be applied as the base material for fabrication of wound dressing and skin care products.

Asunto(s)