Influence of Super-Low-Intensity Microwave Radiation on Mesenchymal Stem Cells

Abstract

Mesenchymal stem cells (MSCs) have emerged as a promising tool for regenerative medicine due to their multipotency and immunomodulatory properties. According to recent research, exposing MSCs to super-low-intensity microwave radiation can have a significant impact on how they behave and operate. This review provides an overview of the most recent studies on the effects of microwave radiation on MSCs with power densities that are much below thermal values. Studies repeatedly show that non-thermal mechanisms affecting calcium signaling, membrane transport, mitochondrial activity, along ion channel activation may increase MSC proliferation, differentiation along mesodermal lineages, paracrine factor secretion, and immunomodulatory capabilities during brief, regulated microwave exposures. These bioeffects greatly enhance MSC regeneration capability in preclinical models of myocardial infarction, osteoarthritis, brain damage, and other diseases. Additional study to understand microwave treatment settings, biological processes, and safety assessments will aid in the translation of this unique, non-invasive strategy of activating MSCs with microwave radiation to improve cell engraftment, survival, and tissue healing results. Microwave-enhanced MSC treatment, if shown safe and successful, might have broad relevance as a novel cell-based approach for a variety of regenerative medicine applications.

Keywords: mesenchymal stem cells; regenerative medicine; super-low-intensity microwave field; tissue regeneration; weak electromagnetic field.

Figure 1

Overview of the effects of weak and super-weak electromagnetic fields on biological systems. External EM fields can interact with organisms at multiple levels, from molecules to whole tissues and organs, producing effects such as changes in enzyme kinetics, ion transport, neurotransmission, blood flow, tissue regeneration, sleep, cognition, and physiological regulation.

Figure 2

Schematic representation of Mesenchymal Stem Cells differentiation process.

Figure 3

CCL20 induces in vitro adhesion of human Th17 cells to MSCs. (A) Flow cytometric analysis of CCR6 expression on fully differentiated human Th17 and Th2 lymphocyte clones. The x-axis represents fluorescence (four-decade log scale), and the y-axis represents relative cell number. Dashed lines indicate staining with isotype-matched control monoclonal antibodies. (B) Adhesion of CFSE-labeled Th17 and Th2 lymphocyte clones to a confluent monolayer of MSCs, pre-incubated or not with TNF-α and IFN-γ (10 ng/mL) for 48 h, in the presence or absence of CCL20 (20 ng/mL). Magnification 312.5x. (C) Flow cytometric analysis of CD54 expression in L cells transfected with CD54 cDNA. Open graphs represent staining with control isotype-matched monoclonal antibodies. (D) Adhesion of Th17 cells to L cells expressing CD54 or wild-type L cells (control) in the presence or absence of CCL20. Magnification 312.5x. (E) Adhesion of Th17 cells to MSCs pre-incubated with medium alone (NA) or with TNF-α and IFN-γ (A), in the presence or absence of CCL20. (F) Adhesion of Th17 cells to L cells expressing CD54 or wild-type L cells (control) in the presence or absence of CCL20. Values represent the mean ± SD of the number of adhered T cells counted in 10 adjacent fields around the center of the chamber, for a total of three independent experiments. Statistical analysis was performed using the Student’s t-test. p * < 0.05; p ** < 0.005.