When talking about stem cells, we come as close to magic as it gets in biology. Of course, it’s only magical in a figurative sense, but it certainly instills hope when you hear that stem cells can become any cell in the body, right? Just think about all the diseases that could be alleviated or even cured. Body parts that have been lost or damaged could be replaced without the usual rejection issues associated with transplants. Those who discuss eternal life often mention stem cells in the same breath, and many attribute rejuvenating properties to stem cells.
Stem cells are cells found in all multicellular organisms, but they were discovered relatively late in medical history. The term was first mentioned in 1908 by the Russian scientist Alexander Maksimov at a congress in Berlin, but it took over fifty years before research really took off. In the 1960s, it was discovered, for example, that bone marrow in mice could renew itself, and it became clear that something significant was underway. The 1990s were the decade when stem cell research truly gained momentum. I was studying nutrition science during the early 1990s, and I distinctly remember how mythical stem cells were portrayed in various contexts, even in strictly scientific settings. Today, research has come a long way, and interestingly, factors that can positively influence the stem cells in our bodies have been identified. Photobiomodulation (PBM), of which RLT (Red Light Therapy) is one form, has been shown to activate our own stem cells, which could explain many of the healing properties of RLT.
How Stem Cells Work
Stem cells possess two fundamental characteristics. Firstly, they can undergo an infinite number of cell divisions while keeping their daughter cells undifferentiated. This means that the body can produce more stem cells if it decides to, and this can be a crucial factor in health and aging. Secondly, what makes stem cells unique is their ability to mature into one or several different types of cells. Stem cells can be categorized into four groups based on their potential to differentiate into various cell types. Totipotent stem cells can become any cell type in the body and are among the earliest stem cells in an embryo. They then become pluripotent stem cells, which can give rise to all cell types except placental cells. Due to their generality and lack of specialization, pluripotent stem cells are the most sought after in research. In the adult body, multipotent stem cells exist, which can produce closely related cell types, such as blood cells, and unipotent stem cells can only produce one type of cell. It is the multipotent and unipotent stem cells that are the focus of research on the effects of RLT on stem cells. The natural function of stem cells is to maintain and repair tissues and organs. If this process can be accelerated, it may theoretically restore damage caused by aging and/or diseases.
The Effect of Red Light on Stem Cells
A lot of research has been conducted on stem cells, with a considerable focus on how they respond to RLT. It turns out that they begin to divide when exposed to light with the right wavelengths (1). Both red and near-infrared light are effective, and one can describe it as the activation of stem cells, causing them to perform their functions when illuminated. Stem cells receive an increase in nitric oxide, ATP (the primary energy currency of cells), and cAMP, all of which stimulate cell division. Many of the healing effects of RLT are likely due to this activation of stem cells, although it’s still challenging to assess its exact magnitude. Nonetheless, stem cell activation is undeniably present and is used, for example, in advanced wound healing (2). Animal studies have also shown that it is possible to improve treatment for osteoporosis, specifically using stem cells (3). However, while conducting studies in test tubes and animal experiments is one thing, the question everyone wants answered is whether RLT treatments can make a difference for the stem cells present in the human body. The answer is yes; it can. A pilot study demonstrated a significant increase in stem cells with regular treatment of the shinbone in test subjects (4). These stem cells are subsequently transported through the bloodstream to areas in the body where old damaged cells need to be replaced. This is regenerative healing at its best, and users will experience real rejuvenation with more intact and well-functioning tissues (5). For example, increased cartilage formation has been observed with the help of activated stem cells, offering great hope for those affected by osteoarthritis (6).
- Khatereh Khorsandi 1, Reza Hosseinzadeh 2, Heidi Abrahamse 3, Reza Fekrazad 4 5 Biological Responses of Stem Cells to Photobiomodulation Therapy. Curr Stem Cell Res Ther. 2020;15(5):400-413. doi: 10.2174/1574888X15666200204123722.
- Stem Cell Res Ther. Enhancing therapeutic efficacy of human adipose-derived stem cells by modulating photoreceptor expression for advanced wound healing. Sang Ho Lee 1, Yu-Jin Kim 1, Yeong Hwan Kim 1, Han Young Kim 2, Suk Ho Bhang 3. 2022 May 26;13(1):215. doi: 10.1186/s13287-022-02892-2.
- Mehrdad Asgari 1 2, Mohammad-Amin Abdollahifar 1, Rouhallah Gazor 2, Tayyebali Salmani 3, Armin Khosravipour 1, Yaser Mahmoudi 4, Farzad Baniasadi 5, Michael R Hamblin 6 7, Heidi Abrahamse 6, Sufan Chien 8 9, Mohammad Bayat 1 8 9. Photobiomodulation and Stem Cell on Repair of Osteoporotic Bones. Photobiomodul Photomed Laser Surg. 2022 Apr;40(4):261-272. doi: 10.1089/photob.2021.0127.
- Amir Oron 1, Shai Efrati 2, Keren Doenyas-Barak 2, Hana Tuby 3, Lidya Maltz 3, Uri Oron 3
Photobiomodul Photomed Laser Surg. Photobiomodulation Therapy to Autologous Bone Marrow in Humans Significantly Increases the Concentration of Circulating Stem Cells and Macrophages: A Pilot Study. 2022 Mar;40(3):178-182. doi: 10.1089/photob.2021.0123. Epub 2022 Feb 21. - Thobekile S Leyane 1, Sandy W Jere 1, Nicolette N Houreld 1. Cellular Signalling and Photobiomodulation in Chronic Wound Repair. Int J Mol Sci. 2021 Oct 18;22(20):11223. doi: 10.3390/ijms222011223.
- C Schneider 1, P Dungel 2, E Priglinger 1, M Danzer 3, B Schädl 4, S Nürnberger 5. The impact of photobiomodulation on the chondrogenic potential of adipose-derived stromal/stem cells. J Photochem Photobiol B. 2021 Aug;221:112243. doi: 10.1016/j.jphotobiol.2021.112243. Epub 2021 Jun 18.
Author: Fredrik Paulún
