E. V. Kuevda

Dynamic decellularization and cross-linking of rat tracheal matrix

Decellularized tissues and organs represent a suitable option for tissue engineering when specific scaffolds are needed. However, the optimal conditions to completely remove all the cellular components and minimally affect the biochemical and structural properties of the extracellular matrix are still to be found. For this aim, bioreactors could be an alternative means to dynamically treat the biological samples, automatically controlling all the variables involved in the process and speeding up the entire procedure in order to deal with a suitable scaffold within a limited time period. This paper presents the characterization of rat tracheae decellularized in dynamic conditions, implementing a detergent-enzymatic method, previously considered. Only 6 cycles were enough to generate a tracheal matrix that was histologically and structurally similar to the native one. The network of collagen, reticular and elastic fibers was well preserved, such as the epithelial cilia, the luminal basement membrane and the main matrix components. The elastin content decreased, even if not significantly, after the decellularization protocol. Mechanical properties of the treated tissues were slightly affected by the procedure, and were partially recovered after crosslinking with genipin, a naturally-derived agent. The use of bioreactors could enhance the decellularization procedure of tissues/organs, but a careful selection of the processing parameters is needed in order to prevent large modifications compared to the native condition.

Evaluation of the influence of decellularization on the changes in biomechanical properties of primate lungs

The effect of decellularization on the biomechanical properties of macaque lungs was studied. The quality of the biological scaffold was additionally assessed by morphological methods, and the contents of extracellular matrix (ECM) fibers were determined both qualitatively and quantitatively. Histological analysis revealed no damage of structural integrity of ECM components, but the scaffold elasticity significantly decreased, which was confirmed by the changes in the hysteresis loop without a concomitant decrease in peak loads, with the mechanical strength of the samples being retained. These changes require taking additional measures to prevent a decrease in the effective lung volume.

Angiogenesis mechanisms in transplantation of tissue-engineered constructions

ВВЕДЕНИЕ Регенеративная медицина, основанная на использовании клеточных механизмов восстановления структур и функций организма, является фундаментальной основой медицины будущего, призванной избавить человечество от многих заболеваний [1]. Данная область является одной из наиболее высокотехнологичных и бурно развивающихся отраслей биомедицинской индустрии [2]. Одной из ключевых задач тканевой инженерии является формирование тканеинженерных конструкций (ТИК), которые могут использоваться в DOI: 10.15825/1995-1191-2017-4-141-145

The Effectiveness of Preimplantation Recellularization of Acellular Rat-Esophagus Matrices Using GFP-Positive Cells

The use of recellularized matrices allows obtaining tissue-engineered structures that largely reproduce the morphofunctional features of native organs and tissues. Doubts as to the advisability of preimplantation recellularization of the scaffold, which are associated with the death of prepopulation cells on the scaffold in vivo, require studying the behavior of cells on plastic and biological implants after recellularization. Rat esophagus that had undergone detergent-enzymatic decellularization was repopulated with GFP-positive cells intensely fluorescing in the green spectrum, which allowed us to trace the status of the initial cell population during cultivation on plastic and after transplantation, determine the viability and metabolic activity of cells, and conduct fluorescent detection of the cells on the scaffold before and after implantation. There were no data on the apparent cell proliferation on the matrix; however, there were indirect indications of metabolic activity and GFP synthesis by the cells that populated the scaffold before implantation.

In Vivo Experimental Study of Biological Compatibility of Tissue Engineered Tracheal Construct in Laboratory Primates

Biological compatibility of a tissue engineered construct of the trachea (synthetic scaffold) and allogenic mesenchymal stem cells was studied on laboratory Papio hamadryas primates. Subcutaneous implantation and orthotopic transplantations of tissue engineered constructs were carried out. Histological studies of the construct showed chaotically located filaments and mononuclear cells fixed to them. Development of a fine connective tissue capsule was found at the site of subcutaneous implantation of the tissue engineered construct. The intact structure of the scaffold populated by various cell types in orthotopic specimens was confirmed by expression of specific proteins. The results indicated biological compatibility of the tissue engineered construct with the mesenchymal stem cells; no tissue rejection reactions were recorded; simulation of respiratory disease therapy on Papio hamadryas proved to be an adequate model.

EPR spectroscopy solutions for assessment of decellularization of intrathoracic organs and tissues.

Using EPR spectroscopy it was established that the determination of the concentration of paramagnetic centers in lyophilized tissues allows indirect evaluation of the quality of decellularization of intrathoracic organs (diaphragm, heart, and lungs), since the content of paramagnetic particles in them can serve as a criterion of cell viability and points to the necessity to repeat decellularization. Experiments in rats showed that the EPR spectra of the native thoracic organs contained paramagnetic centers with g-factor values ranging from 2.007 to 2.011 at a concentration of 10–8 to 6.62 × 10–7 mol/g of lyophilized tissue, whereas in all decellularized tissues of the same organs paramagnetic particles were not detected.

Regenerating the Respiratory Tract

The ultimate target of regenerative medicine approaches (tissue engineering and cell therapy) for irreversible diseases of the respiratory tract is to replace or restore tissues or organ function. In this chapter we will describe the basic developmental biology of the respiratory system, and highlight the endogenous and exogenous stem or progenitor cells that are involved in tissue regeneration and homeostasis in the respiratory tract. We will also review the different therapeutic approaches to understand how a reconstituted complex whole tissue or organ can remodel, regenerate, and repair via specific mechanisms. We describe a mesenchymal stem-cell-like mucoepidermoid tumor cell population (MEi cells) in the human respiratory tract; and provide an overview of the innovative applications that nanotechnology can offer to accelerate the field of TE and cell therapy.