Photobiomodulation for stem cell modulation and regenerative medicine -WALT position paper 2025

This position paper reviews the various effects of combination therapy by photobiomodulation therapy (PBMT) and stem cells, on different parts of the body. The aim of this paper is to reach consensus on recommendations for the parameters of PBMT regarding its application on stem cells. A significant number of studies involving PBMT, and stem cells have been published. The advantages of this combination therapy on tissue regeneration, cell differentiation and proliferation, and healing have been reported in many studies. Due to the diverse nature of study designs used with respect to light parameters, as well as a lack of well designed, ethically approved clinical trials, clinicians may benefit from suggested guidelines for clinical application based on data obtained from previous studies. These guidelines would also help researchers in designing future studies. An in-depth review of literature on the effect of PBMT on stem cells at a molecular, cellular and tissue specific level was performed, using experts in each field of PBMT. Depending on the number of studies in each field, recommendations are presented which can suggest further studies on stem cells and PBMT. PBMT has diverse applications on stem cells. Both in-vivo and in-vitro studies represent the effectiveness of PBMT in conjunction with stem cell therapy in cell proliferation, differentiation, tissue regeneration, wound healing, angiogenesis, and treatment of different diseases. However, there is a considerable lack of clinical studies in all the reviewed fields. In each category, we attempted to recommend a PBMT protocol based on information from literature, experience, and expertise. Protocols for PBMT on stem cells were reviewed in each field of medicine, and recommendations were made for further clinical studies. Not surprising, the main wavelengths used in PBMT studies in relation to stem cells, were in the range of 630-660 nm, and 800-890 nm. However, other laser parameters are in a very wide range of difference, depending on the tissue that PBMT was applied or the aim of its application.