Enhancing the Therapeutic Potential of Mesenchymal Stem Cells with Light‐Emitting Diode: Implications and Molecular Mechanisms

Abstract

This study evaluated the effects of light-emitting diode (LED) on mesenchymal stem cells (MSCs). An electronic search was conducted in PubMed/MEDLINE, Scopus, and Web of Science database for articles published from 1980 to February 2020. Ten articles met the search criteria and were included in this review. The risk of bias was evaluated to report quality, safety, and environmental standards. MSCs were derived from adipose tissue, bone marrow, dental pulp, gingiva, and umbilical cord. Protocols for cellular irradiation used red and blue light spectrum with variations of the parameters. The LED has been shown to induce greater cellular viability, proliferation, differentiation, and secretion of growth factors. The set of information available leads to proposing a complex signaling cascade for the action of photobiomodulation, including angiogenic factors, singlet oxygen, mitogen-activated protein kinase/extracellular signal-regulated protein kinase, Janus kinase/signal transducer, and reactive oxygen species. In conclusion, although our results suggest that LED can boost MSCs, a nonuniformity in the experimental protocol, bias, and the limited number of studies reduces the power of systematic review. Further research is essential to find the optimal LED irradiation parameters to boost MSCs function and evaluate its impact in the clinical setting.

Light‐emitting Diode Can Enhance the Metabolism and Paracrine Action of Mesenchymal Stem Cells

“…To the best of our knowledge, most studies have evaluated the role of low‐level laser in modulating MSCs, but there is less evidence of the biological repercussions of LED on MSCs (22). Although lasers emit coherent light and LED emit non‐coherent light, both can produce similar photobiological effects when applied with the same irradiation parameters (23).…”

“…Moreover, in vitro-based experiments can be performed at controlled conditions and thus can provide accurate and reproducible results (24) on LED-irradiated MSCs. In this regard, we recently summarized the current evidence about the effects of LED on the viability, proliferation, differentiation, cell metabolism, and secretion of angiogenic factors of MSCs (22). Although preconditioning of MSCs with LEDs before transplantation may be a usual procedure to improve tissue engineering and cell therapy in the future, the small number of studies and lack of optimal LED parameters limit the power of the findings (22,25).…”

Effects of Red LED Irradiation in Enhancing the Mineralization of Human Dental Pulp Cells In Vitro

“…Current evidence indicates that hard-tissue regeneration depends on stem or stem-like cell dynamics involving cell proliferation, differentiation, and mineralization. Some authors suggest that red LEDI can modulate stem-cell proliferation, whereas others claim that red LEDI does not alter cell proliferation but enhances cell differentiation and mineralization [15][16][17][18]. Moreover, the timing of red LEDI applications is also controversial.…”

Enhancing osteogenic differentiation in adipose-derived mesenchymal stem cells with Near Infra-Red and Green Photobiomodulation

“…Furthermore, light doses above 7 J/cm 2 tend to provoke the biphasic dose response subsequently inducing cell death [ 47 , [49] , [50] , [51] ]. However, if the biphasic dose response is avoided, PBM has been shown by several researchers [ [52] , [53] , [54] ] to have positive effects on inflammation, oxidative stress, survival, and tissue regeneration [ 55 ]. As a result of its virtually non-existent adverse effects, PBM appears to improve treatment outcomes [ 50 ].…”