Polymer Kernels as Compact Carriers for Suspended Cardiomyocytes

Abstract

Induced pluripotent stem cells (iPSCs) constitute a potential source of patient-specific human cardiomyocytes for a cardiac cell replacement therapy via intramyocardial injections, providing a major benefit over other cell sources in terms of immune rejection. However, intramyocardial injection of the cardiomyocytes has substantial challenges related to cell survival and electrophysiological coupling with recipient tissue. Current methods of manipulating cell suspensions do not allow one to control the processes of adhesion of injected cells to the tissue and electrophysiological coupling with surrounding cells. In this article, we documented the possibility of influencing these processes using polymer kernels: biocompatible fiber fragments of subcellular size that can be adsorbed to a cell, thereby creating the minimum necessary adhesion foci to shape the cell and provide support for the organization of the cytoskeleton and the contractile apparatus prior to adhesion to the recipient tissue. Using optical excitation markers, the restoration of the excitability of cardiomyocytes in suspension upon adsorption of polymer kernels was shown. It increased the likelihood of the formation of a stable electrophysiological coupling in vitro. The obtained results may be considered as a proof of concept that the stochastic engraftment process of injected suspension cells can be controlled by smart biomaterials.

Human sodium current voltage-dependence at physiological temperature measured by coupling patch-clamp experiment to a mathematical model

“…The flow cytometry data for cardiac markers cardiac troponin T (cTnT) and immunostainings for ventricle-type β-myosin regulatory light chain (MLC2), β-myosin heavy chain (MHC) and cardiomyocyte transcription factor NKX2.5 are reported previously (Podgurskaya et al, 2019). An increase in cx43 expression during directed differentiation was verified in (Slotvitsky et al, 2020(Slotvitsky et al, , 2022, which corresponds to the literature data on the maturation of ventricular-like iPSC-derived cardiomyocytes (Tan & Ye, 2018). The efficiency of directed iPSC differentiation into cardiomyocytes estimated by the cTnT expression was 47% (Dementyeva et al, 2019).…”

Novel Molecular Vehicle-Based Approach for Cardiac Cell Transplantation Leads to Rapid Electromechanical Graft–Host Coupling

“…Furthermore, dispersed cells can leave the injection site and have a low survival rate [ 7 ], whereas a significant proportion of the cells do not graft into the host tissue [ 17 ]. The latter is due to the fact that the continuous presence of adhesion sites is necessary for the normal functioning of iPSC-CM, and in its absence, the viability and functionality of the cardiomyocyte are limited [ 18 ]. On the contrary, tissue-engineered constructs demonstrate improved survival and cell viability after transplantation, but the shape and size of the graft impose restrictions on the method of delivery to the host tissue and challenge electrophysiological coupling [ 15 , 16 ].…”

“…For this purpose, the supporting cell “scaffold” represents a number of isolated fragments of polymer nanofibers capable of carrying solitary cells. As a material for polymeric nanofibers, we used poly-L-lactide (PLLA), a biocompatible and biodegradable polymer widely used for medical purposes: the resulting fibers turned out to be thinner than native fibroin fibers [ 21 ], and human fibronectin (HFN) was used to optimize the adhesive properties of the fiber surface [ 18 ]. It should be noted that making the optimal choice of polymer composition is a complex and global task [ 22 ].…”

“…An approach to a polymer nanofiber as a sufficient cell substrate has been previously demonstrated in vitro. Polymer fiber fragments of subcellular sizes coated with HFN are a satisfactory substrate for the cultivation of both neonatal rat ventricular cardiomyocytes (NRVMs) and induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) [ 18 , 21 ], with the latter having the greatest potential for clinical use [ 4 ]. Cell adhesion to a single fiber leads to the appearance of a remarkable “sheath” structure, enveloping fiber, thus substantially increasing the contact zone and eventually forcing the cell to attach to itself [ 21 ].…”

“…Thus, the scaffold moves “inside” the cell (topologically remaining outside of the cell membrane, which is curved in such a way as to create an invagination to envelop the fiber with the cell). The main consequence of this cell–fiber interaction is the restoration of excitability and mechanical contractions [ 21 ] in a solitary cell that were lost during enzymatic methods of cell isolation [ 9 , 18 ]. As a result, the cell injection solution, instead of a suspension of solitary cardiomyocytes, represents a suspension of cells on compact carriers.…”