by Keyword: Tissue slice

Jurado A, Ulldemolins A, Lluís H, Gasull X, Gavara N, Sunyer R, Otero J, Gozal D, Almendros I, Farré R, (2023). Fast cycling of intermittent hypoxia in a physiomimetic 3D environment: A novel tool for the study of the parenchymal effects of sleep apnea Frontiers In Pharmacology 13, 1081345-1081345

Background: Patients with obstructive sleep apnea (OSA) experience recurrent hypoxemic events with a frequency sometimes exceeding 60 events/h. These episodic events induce downstream transient hypoxia in the parenchymal tissue of all organs, thereby eliciting the pathological consequences of OSA. Whereas experimental models currently apply intermittent hypoxia to cells conventionally cultured in 2D plates, there is no well-characterized setting that will subject cells to well-controlled intermittent hypoxia in a 3D environment and enable the study of the effects of OSA on the cells of interest while preserving the underlying tissue environment.Aim: To design and characterize an experimental approach that exposes cells to high-frequency intermittent hypoxia mimicking OSA in 3D (hydrogels or tissue slices).Methods: Hydrogels made from lung extracellular matrix (L-ECM) or brain tissue slices (300-800-mu m thickness) were placed on a well whose bottom consisted of a permeable silicone membrane. The chamber beneath the membrane was subjected to a square wave of hypoxic/normoxic air. The oxygen concentration at different depths within the hydrogel/tissue slice was measured with an oxygen microsensor.Results: 3D-seeded cells could be subjected to well-controlled and realistic intermittent hypoxia patterns mimicking 60 apneas/h when cultured in L-ECM hydrogels & AP;500 mu m-thick or ex-vivo in brain slices 300-500 mu m-thick.Conclusion: This novel approach will facilitate the investigation of the effects of intermittent hypoxia simulating OSA in 3D-residing cells within the parenchyma of different tissues/organs.

JTD Keywords: 3d culture, cell culture, diffusion, disease model, hydrogels, hypoxia, model, oxygen diffusion, tissue slice, transport, 3d culture, Cell culture, Disease model, Hydrogels, Hypoxia, Obstructive sleep apnea, Oxygen, Oxygen diffusion, Tissue slice

Narciso M, Ulldemolins A, Júnior C, Otero J, Navajas D, Farré R, Gavara N, Almendros I, (2022). Novel Decellularization Method for Tissue Slices Frontiers In Bioengineering And Biotechnology 10, 832178

Decellularization procedures have been developed and optimized for the entire organ or tissue blocks, by either perfusion of decellularizing agents through the tissue’s vasculature or submerging large sections in decellularizing solutions. However, some research aims require the analysis of native as well as decellularized tissue slices side by side, but an optimal protocol has not yet been established to address this need. Thus, the main goal of this work was to develop a fast and efficient decellularization method for tissue slices—with an emphasis on lung—while attached to a glass slide. To this end, different decellularizing agents were compared for their effectiveness in cellular removal while preserving the extracellular matrix. The intensity of DNA staining was taken as an indicator of remaining cells and compared to untreated sections. The presence of collagen, elastin and laminin were quantified using immunostaining and signal quantification. Scaffolds resulting from the optimized protocol were mechanically characterized using atomic force microscopy. Lung scaffolds were recellularized with mesenchymal stromal cells to assess their biocompatibility. Some decellularization agents (CHAPS, triton, and ammonia hydroxide) did not achieve sufficient cell removal. Sodium dodecyl sulfate (SDS) was effective in cell removal (1% remaining DNA signal), but its sharp reduction of elastin signal (only 6% remained) plus lower attachment ratio (32%) singled out sodium deoxycholate (SD) as the optimal treatment for this application (6.5% remaining DNA signal), due to its higher elastin retention (34%) and higher attachment ratio (60%). Laminin and collagen were fully preserved in all treatments. The SD decellularization protocol was also successful for porcine and murine (mice and rat) lungs as well as for other tissues such as the heart, kidney, and bladder. No significant mechanical differences were found before and after sample decellularization. The resulting acellular lung scaffolds were shown to be biocompatible (98% cell survival after 72 h of culture). This novel method to decellularize tissue slices opens up new methodological possibilities to better understand the role of the extracellular matrix in the context of several diseases as well as tissue engineering research and can be easily adapted for scarce samples like clinical biopsies. Copyright © 2022 Narciso, Ulldemolins, Júnior, Otero, Navajas, Farré, Gavara and Almendros.

JTD Keywords: biocompatibility, bioscaffold recellularization, extracellular matrix, flow, impact, lung, scaffolds, tissue slices, Ammonia, Bio-scaffolds, Biocompatibility, Biological organs, Bioscaffold recellularization, Cell removal, Cells, Collagen, Cytology, Decellularization, Dna, Dna signals, Elastin, Extracellular matrices, Extracellular matrix, Extracellular-matrix, Glycoproteins, Laminin, Lung, Mammals, Recellularization, Scaffolds (biology), Sodium deoxycholate, Sulfur compounds, Tissue, Tissue slice, Tissue slices