Treatment of Kleine-Levin Syndrome With Intranasal Photobiomodulation and Methylene Blue

Photobiomodulation improves depression symptoms: a systematic review and meta-analysis of randomized controlled trials

Background

Depression is a common mental illness that is widely recognized by its lack of pleasure, fatigue, low mood, and, in severe cases, even suicidal tendencies. Photobiomodulation (PBM) is a non-invasive neuromodulation technique that could treat patients with mood disorders such as depression.

Methods

A systematic search of ten databases, including randomized controlled trials (RCTs) for depression, was conducted from the time of library construction to September 25, 2023. The primary outcome was depression. The secondary outcome was sleep. Meta-analysis was performed using RevMan (version 5.4) and Stata (version 14.0). Subgroup analyses were performed to identify sources of heterogeneity. The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE).

Results

Three thousand two hundred and sixty-five studies were retrieved from the database and screened for inclusion in eleven trials. The forest plot results demonstrated that PBM alleviated depression (SMD = -0.55, 95% CI [-0.75, -0.35], I2 = 46%). But it is not statistically significant for patients' sleep outcomes (SMD = -0.82, 95% CI [-2.41, 0.77], I2 = 0%, p > 0.05). Subgroup analysis showed that s-PBM was superior to t-PBM in relieving symptoms of depression. The best improvement for t-PBM was achieved using a wavelength of 823 nm, fluence of 10-100 J/cm2, irradiance of 50-100 mW/cm2, irradiance time of 30 min, treatment frequency < 3/week, and number of treatments >15 times. The best improvement for s-PBM was achieved using a wavelength of 808 nm, fluence ≤1 J/cm2, irradiance of 50-100 mW/cm2, irradiance time ≤ 5 min, treatment frequency ≥ 3/week, number of treatments >15 times. All results had evidence quality that was either moderate or very low, and there was no bias in publication.

Conclusion

We conclude that PBM is effective in reducing depression symptoms in patients. However, the current number of studies is small, and further studies are needed to extend the current analysis results.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, CRD42023444677.

Photobiomodulation Therapy and the Glymphatic System: Promising Applications for Augmenting the Brain Lymphatic Drainage System

The glymphatic system is a glial-dependent waste clearance pathway in the central nervous system, devoted to drain away waste metabolic products and soluble proteins such as amyloid-beta. An impaired brain glymphatic system can increase the incidence of neurovascular, neuroinflammatory, and neurodegenerative diseases. Photobiomodulation (PBM) therapy can serve as a non-invasive neuroprotective strategy for maintaining and optimizing effective brain waste clearance. In this review, we discuss the crucial role of the glymphatic drainage system in removing toxins and waste metabolites from the brain. We review recent animal research on the neurotherapeutic benefits of PBM therapy on glymphatic drainage and clearance. We also highlight cellular mechanisms of PBM on the cerebral glymphatic system. Animal research has shed light on the beneficial effects of PBM on the cerebral drainage system through the clearance of amyloid-beta via meningeal lymphatic vessels. Finally, PBM-mediated increase in the blood–brain barrier permeability with a subsequent rise in Aβ clearance from PBM-induced relaxation of lymphatic vessels via a vasodilation process will be discussed. We conclude that PBM promotion of cranial and extracranial lymphatic system function might be a promising strategy for the treatment of brain diseases associated with cerebrospinal fluid outflow abnormality.