So-Young Chang, Nathaniel T. Carpena, Bong Jin Kang, Min Young Lee
Beckman Laser Institute Korea, Dankook University, Cheonan, Korea, Department of Otolaryngology-Head & Neck Surgery, College of Medicine, Dankook University, Cheonan, Korea, Department of Anesthesia and Pain medicine, College of Medicine, Dankook University, Cheonan, Korea
ABSTRACT
The use of stem cell therapy to treat various diseases has become a promising approach. The ability of stem cells to self-renew and differentiate can contribute significantly to the success of regenerative medical treatments. In line with these expectations, there is a great need for an efficient research methodology to differentiate stem cells into their specific targets. Photobiomodulation (PBM), formerly known as low-level laser therapy (LLLT), is a relatively non-invasive technique that has a therapeutic effect on damaged tissue or cells. Recent advances in adapting PBM to stem cell therapy showed that stem cells and progenitor cells respond favorably to light. PBM stimulates different types of stem cells to enhance their migration, proliferation, and differentiation in vitro and in vivo. This review summarizes the effects of PBM on targeted differentiation across multiple stem cell lineages. The analytical expertise gained can help better understand the current state and the latest findings in PBM and stem cell therapy.
INTRODUCTION
Stem cells play an important role as the source of tissue-organ maintenance as they pitch in for repair of injured tissues with their self-renewing capacity and ability to differentiate into multiple target phenotypes. Therefore, stem cell therapy may be a promising treatment option for the regenerative medicine field. There are two types of stem cells: embryonic stem cells (ESC) and adult stem cells. However recently, stem cell research has been conducted primarily using adult stem cells. Between 2013 up until writing this review, only one published study used ESC in relation to PBM research, while all other research papers were using adult stem cells. Adult stem cells exist in various organs of our body and are capable of regenerating when the body is damaged. Mesenchymal stem cells (MSC) can be easily isolated from adipose, bone marrow, umbilical cord, and dental pulp, have been studied extensively in tissue engineering and regenerative medicine of different organs as an alternative to conventional treatment methods. Despite the high differentiation potential, the slow proliferation rate of MSCs is an important factor inhibiting its development as an effective treatment. Therefore, establishing a way to accelerate the MSC’s proliferation process is a very important requirement for its success. Photobiomodulation (PBM) is a non-thermal and non-invasive stimulating process to target using wavelengths from the red to near-infrared light spectrum (600 to 1000nm). Formerly called as low-level laser (light) therapy (LLLT), it has been reported that both coherent and non-coherent light sources such as light-emitting diodes (LEDs) have the same therapeutic effect. In light of this, the associations have agreed and acknowledged the re-naming of LLLT into PBM. Its beneficial effects have been
shown in many different diseases by modulating cellular functions such as differentiation, proliferation and migration leading to tissue or cell regeneration. In recent years, the potential importance of PBM is emerging as a clinical tool in regenerative medicine. PBM has been reported to have positive and promising effects in relation to MSCs proliferation and differentiation. However, the bio-stimulation mechanisms of these effects remain partially unclear.