Potential and Challenges of Transcranial Photobiomodulation for the Treatment of Stroke

Abstract

Photobiomodulation (PBM), also known as low-level laser therapy, employs red or near-infrared light emitted from a laser or light-emitting diode for the treatment of various conditions. Transcranial PBM (tPBM) is a form of PBM that is delivered to the head to improve brain health, as tPBM enhances mitochondrial function, improves antioxidant responses, reduces inflammation, offers protection from apoptosis, improves blood flow, increases cellular energy production, and promotes neurogenesis and neuroplasticity. As such, tPBM holds promise as a treatment for stroke. This review summarizes recent findings on tPBM as a treatment for stroke, presenting evidence from both animal studies and clinical trials that demonstrate its efficacy. Additionally, it discusses the potential and challenges encountered in the translation process. Furthermore, it proposes new technologies and directions for the development of light-delivery methods and emphasizes the need for extensive studies to validate and widen the application of tPBM in future treatments for stroke.

Keywords: animal studies; clinical trials; low‐level laser therapy; photobiomodulation; stroke.

FIGURE 1

Schematic representation of tPBM effects in ischemic stroke. tPBM delivers red and NIR light, which is absorbed by the mitochondrial chromophore‐CCO. This absorption promotes ATP generation and affects ROS production, activates transcription factors and signaling pathways. These cascades lead to various photobiological effects, including reduced oxidative stress, neuronal apoptosis, inflammation, and increased neurotrophic levels, angiogenesis, and neuroplasticity, contributing to brain recovery in ischemic stroke.

FIGURE 2

Several potential tPBM delivery approaches for future stroke research. This could involve using safer LED array devices instead of lasers, as well as applying high‐fluence PW light rather than CW. Combining targeted application to specific brain regions, such as the ipsilateral side and default mode network, with multiple treatment sessions may enhance tPBM's neuroprotective and restorative effects. Additionally, intranasal tPBM using light‐emitting nasal devices could provide efficient near‐infrared light delivery to deep brain structures.