Nuclear magnetic resonance footprint of Wharton Jelly mesenchymal stem cells death mechanisms and distinctive in-cell biophysical properties in vitro.

The importance of the biophysical characterization of mesenchymal stem cells (MSCs) was recently pointed out for supporting the development of MSC-based therapies. Among others, tracking MSCs in vivo and a quantitative characterization of their regenerative impact by nuclear magnetic resonance (NMR) demands a full description of MSCs' MR properties. In the work, Wharton Jelly MSCs are characterized in a low magnetic field (LF) in vitro by using different approaches. They encompass various settings: MSCs cultured in a Petri dish and cell suspensions; experiments- 1D-T 1 , 1D-T 2 , 1D diffusion, 2D T 1 -T 2 and D-T 2 ; devices- with a bore aperture and single-sided one. Complex NMR analysis with the aid of random walk simulations allows the determination of MSCs T 1 and T 2 relaxation times, cells and nuclei sizes, self-diffusion coefficients of the nucleus and cytoplasm. In addition, the influence of a single layer of cells on the effective diffusion coefficient of water is detected with the application of a single-sided NMR device. It also enables the identification of apoptotic and necrotic cell death and changed diffusional properties of cells suspension caused by compressing forces induced by the subsequent cell layers. The study delivers MSCs-specific MR parameters that may help tracking MSCs in vivo.