Photobiomodulation (Red/Near-Infrared Light Therapy) in Amyotrophic Lateral Sclerosis (ALS)

Introduction

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive neurodegenerative disease characterized by the loss of upper and lower motor neurons, leading to muscle weakness, spasticity, and eventual respiratory failure. Despite advances in disease-modifying therapies (e.g., riluzole, edaravone), ALS remains incurable and many patients seek supportive treatments to slow progression or ease symptoms. Photobiomodulation (PBM)—also called low-level laser therapy—uses red to near-infrared (NIR) light (∼600–1100 nm) to modulate cellular function. Although clinical data in ALS are sparse, emerging reports and reviews suggest PBM’s neuroprotective, anti-inflammatory, and mitochondrial-enhancing effects could benefit motor neuron survival and patient function.

Mechanisms of Action

1. Mitochondrial Enhancement
   PBM photons are absorbed by mitochondrial cytochrome c oxidase, boosting electron transport, ATP production, and cellular energy availability—crucial in ALS, where mitochondrial dysfunction and energy failure drive neurodegeneration mdpi.com.

2. Oxidative Stress & Excitotoxicity Reduction
   By improving mitochondrial redox balance, PBM reduces reactive oxygen/nitrogen species that contribute to motor neuron damage. It also modulates calcium flux in neurons, mitigating excitotoxic pathways common in ALS mdpi.com.

3. Anti-Inflammatory & Neuroprotective Signaling
   PBM downregulates pro-inflammatory cytokines (e.g., TNF-α, IL-1β) and may upregulate neurotrophic factors like BDNF. This dual action can calm glial activation and support neuronal survival and synaptic plasticity.

Wavelengths Explored in ALS Context

Clinical Evidence

1. Case Report (Longo et al., 2009)

A single 69-year-old man with limb-onset ALS underwent 810 nm and 890 nm laser therapy (three 20-day cycles, twice daily, 4–15 J/cm²). After each cycle, he experienced measurable gains in muscle strength and respiratory autonomy, though benefits waned 20–30 days post-treatment researchgate.net.

2. Systematic Review of Neuromodulation (Jiménez-García et al., 2024)

A PLOS ONE meta-analysis of 10 ALS neuromodulation studies (including photonic stimulation) found significant improvements in muscle stretch measures (p = 0.012), resting motor threshold (p = 0.0457), and overall functionality (p = 0.007), though quality of life and isometric strength showed mixed results. PBM was highlighted as an innovative approach to reduce excitotoxicity via mitochondrial support researchgate.net.

3. Literature Review (Moskvin, 2024)

Sergey Moskvin’s review synthesized English and Russian publications on LLLT in ALS, describing techniques such as intravenous laser blood illumination (ILBI), noninvasive laser blood illumination (NLBI), and local transcranial/spinal exposure. Based on decades of clinical experience, the author concludes these PBM modalities are promising for symptom management and functional support, warranting rigorous trials pubmed.ncbi.nlm.nih.gov.

PBM as an Adjunct to Standard Therapies

All reported PBM protocols in ALS trials have been delivered alongside conventional treatments (e.g., riluzole, physical therapy), with no safety concerns or adverse interactions reported. Because PBM targets mitochondrial dysfunction and oxidative stress—pathways not directly addressed by existing drugs—it may complement pharmacotherapy to slow motor neuron loss and alleviate residual symptoms.

Safety and Tolerability

Across the limited clinical reports, PBM has been well tolerated with no serious adverse events. Common parameters (up to 15 J/cm² per session, multiple sessions over weeks) appear safe, making PBM a low-risk adjunct worth exploring in ALS patient care.

Conclusion

While robust randomized trials in ALS are lacking, preliminary human data and reviews underscore PBM’s theoretical plausibility and early clinical promise. Key takeaways:

• Mechanisms: PBM boosts mitochondrial ATP, reduces ROS/excitotoxicity, and modulates inflammation—core processes in ALS pathology.

• Wavelengths: 810 nm has demonstrated transient motor and respiratory improvements; ILBI at 632–650 nm is widely practiced in Russian centers.

• Evidence: One documented case report; systematic meta-analysis supports neuromodulation benefits; literature reviews advocate expanded clinical research.

• Next Steps: Larger, placebo-controlled trials are needed to define optimal PBM parameters (wavelength, dose, site, frequency) and to confirm whether PBM can meaningfully slow ALS progression or improve patient quality of life.

Given its non-invasive nature and favorable safety profile, PBM represents a compelling avenue for ALS support—one that deserves prioritized investigation alongside emerging pharmacotherapies.

References

• Longo L, Postiglione M, Gabellini M, Longo D. Amyotrophic lateral sclerosis (ALS) treated with low level LASER therapy (LLLT): A case report researchgate.net

• Jiménez-García AM, Bonnel G, Álvarez-Mota A, Arias N. Current perspectives on neuromodulation in ALS patients: A systematic review and meta-analysis. PLOS ONE. 2024. researchgate.net

• Moskvin SV. A brief literature review of low-level laser therapy for treating amyotrophic lateral sclerosis and confirmation of its effectiveness. Biomedicine. 2024. pubmed.ncbi.nlm.nih.gov

• Neshasteh-Riz A, Ghadaksaz A, Hamblin MR. Mechanistic aspects of photobiomodulation therapy in the nervous system. Laser Med. Sci. 2021. mdpi.com