Did human hairlessness allow natural photobiomodulation 2 million years ago and enable photobiomodulation therapy today? This can explain the rapid expansion of our genus’s brain

Photobiomodulation for Major Depressive Disorder: Linking Transcranial Infrared Light, Biophotons and Oxidative Stress

ABSTRACT

Incompletely treated major depressive disorder (MDD) poses an enormous global health burden. Conventional treatment for MDD consists of pharmacotherapy and psychotherapy, though a significant number of patients do not achieve remission with such treatments. Transcranial photobiomodulation (t-PBM) is a promising novel therapy that uses extracranial light, especially in the near-infrared (NIR) and red spectra, for biological and therapeutic effects. The aims of this Review are to evaluate the current clinical and preclinical literature on t-PBM in MDD and to discuss candidate mechanisms for effects of t-PBM in MDD, with specific attention to biophotons and oxidative stress. A search on PubMed and ClinicalTrials.gov identified clinical and preclinical studies using t-PBM for the treatment of MDD as a primary focus. After a systematic screening, only 19 studies containing original data were included in this review (9 clinical and 10 preclinical trials). Study results demonstrate consensus that t-PBM is a safe and potentially effective treatment; however, varying treatment parameters among studies complicate definitive conclusions about efficacy. Among other mechanisms of action, t-PBM stimulates the complex IV of the mitochondrial respiratory chain and induces an increase in cellular energy metabolism. We suggest that future trials include biological measures to better understand the mechanisms of action of t-PBM and to optimize treatment efficiency. Of particular interest going forward will be studying potential effects of t-PBM-an external light source on the NIR spectra-on neural circuitry implicated in depression.

Photobiomodulation as a promising new tool in the management of psychological disorders: A systematic review

Photobiomodulation is a brain modulation technique that has become a promising treatment for multiple pathologies. This systematic review collects studies up to 2019 about the beneficial effects of photobiomodulation as a therapy for treating psychological disorders and a tool for modulating cognitive processes. This technique is mostly used for the treatment of depression and stress, as well as to study its effects on psychological variables in healthy subjects. Despite the lack of parameters used, photobiomodulation seems to achieve enough brain penetration to produce beneficial effects in healthy subjects and patients with multiple pathologies. The best parameters are the wavelengths of 810 nm for the treatment of depression and 1064 nm for cognitive enhancement, along with a scalp irradiance of 250 mW/cm² and a scalp yield of 60 J/cm². It weekly application on the bilateral prefrontal area and the default mode network seems to be ideal for the maintenance of the effects. Photobiomodulation could be used as an effective and safe therapy for the treatment of multiple psychological pathologies.

Claims of anomalously long fasting: An assessment of the evidence from investigated cases

BACKGROUND

Throughout history and to the present day, there have been reports of people claiming inedia, i.e., an anomalous long-term abstinence from food or from food and fluid. Some were isolated and monitored and their abstinences confirmed. This raises the question of whether there may be an anomaly with wide implications that science has overlooked. On the other hand, there have been cases of exposed fraud. The reports on the studies are scattered and it can be difficult to judge their rigor and the strength and implications of their evidence. A critical evaluation seems useful.

OBJECTIVES

The objectives were to obtain an overview of investigated cases of claimed inedia, to assess the anomaly of the claims and study results, to assess the quality of the studies, and to identify deception methods to inform future safeguards.

METHOD

I developed criteria for differentiating normal from anomalous nutrition and fasting and for assessing the quality of inedia studies. Studies found through a systematic search were then assessed and the features of cases of fraud extracted.

RESULTS

47 eligible investigations of 38 claimants were found. Out of the 38 cases, results were assessed as (seemingly) anomalous in 11, with nine cases of monitored food and fluid deprivation ranging from 14 to 68 days (median 28 days), and two cases of food deprivation for 365 and 411 days. In 17 cases, anomaly was assessed as not confirmed due to issues with study design or reporting. Fraud was established in 10 cases. Deception methods were creative. Post-1900 studies were also assessed for quality. Quality was not considered adequate in any.

CONCLUSIONS

I consider the evidential status of inedia unconfirmed as no assessed study had both anomalous findings and impeccable quality. However, quality was often downgraded due to reporting issues and it cannot be concluded in reverse that all claimants with anomalous results were able to deceive the investigators. The results of many studies are curious and demand further research. The conducted analysis provides guidance for improving rigor and transparency in future studies.

Sunlight and health: shifting the focus from vitamin D3 to photobiomodulation by red and near-infrared light

Both sun exposure and serum vitamin D levels have been associated with lower risks of all-cause mortality and chronic age-related diseases, e.g., cancer, diabetes and cardiovascular disease, in epidemiological studies. These associations have mainly been ascribed to beneficial effects of vitamin D. However, a vast body of randomized controlled trials (RCTs) and Mendelian randomization studies have failed to confirm any major health benefits from vitamin D supplementation. In this review, we present tentative evidence showing that red and near-infrared light, both being present in sunlight, could explain the associations between sunlight exposure and better health status. Body irradiation with red and near-infrared light, usually termed as photobiomodulation (PBM), has demonstrated beneficial effects in animal models of chronic diseases. Beyond this, preliminary evidence from RCTs suggest potential clinical benefit from PBM for chronic diseases. PBM is currently being investigated in many pre-registered clinical trials, results of which will eventually clarify the role of red and near-infrared light in the prevention and treatment of common age-related chronic diseases.

Transcranial and systemic photobiomodulation for major depressive disorder: A systematic review of efficacy, tolerability and biological mechanisms

BACKGROUND

Photobiomodulation (PBM) with red and near-infrared light (NIR) -also known as Low-Level Light Therapy-is a low risk, inexpensive treatment-based on non-retinal exposure-under study for several neuropsychiatric conditions. The aim of this paper is to discuss the proposed mechanism of action and to perform a systematic review of pre-clinical and clinical studies on PBM for major depressive disorder (MDD).

METHODS

A search on MEDLINE and EMBASE databases was performed in July 2017. No time or language restrictions were used. Studies with a primary focus on MDD and presenting original data were included (n = 17). References on the mechanisms of action of PBM also included review articles and studies not focused on MDD.

RESULTS

Red and NIR light penetrate the skull and modulate brain cortex; an indirect effect of red and NIR light, when delivered non-transcranially, is also postulated. The main proposed mechanism for PBM is the enhancement of mitochondrial metabolism after absorption of NIR energy by the cytochrome C oxidase; however, actions on other pathways relevant to MDD are also reported. Studies on animal models indicate a benefit from PBM that is comparable to antidepressant medications. Clinical studies also indicate a significant antidepressant effect and good tolerability.

LIMITATIONS

Clinical studies are heterogeneous for population and treatment parameters, and most lack an appropriate control.

CONCLUSIONS

Preliminary evidence supports the potential of non-retinal PBM as a novel treatment for MDD. Future studies should clarify the ideal stimulation parameters as well as the overall efficacy, effectiveness and safety profile of this treatment.

Wnt/β-catenin and ERK pathway activation: A possible mechanism of photobiomodulation therapy with light-emitting diodes that regulate the proliferation of human outer root sheath cells

BACKGROUND

Outer root sheath cells (ORSCs) play important roles in maintaining hair follicle structure and provide support for the bulge area. The hair growth promoting effects of photobiomodulation therapy (PBMT) have been reported, but the mechanisms for this in human ORCs (hORSCs) have rarely been studied.

OBJECTIVE

The aim of this study was to investigate the effect of various wavelengths of light-emitting diode (LED) irradiation on human ORSCs (hORSCs).

METHODS

LED irradiation effects on hORSC proliferation and migration were examined with MTT assay, BrdU incorporation assay and migration assays. hORSCs were irradiated using four LED wavelengths (415, 525, 660, and 830 nm) with different low energy levels. LED irradiation effects on the expression of molecules associated with the Wnt/β-catenin signaling and ERK pathway, hair stem cell markers, and various growth factors and cytokines in hORSCs were examined with real-time PCR and Western blot assay. The effect of the LED-irradiated hORSCs on cell proliferation of human dermal papilla cells (hDPCs) was examined with co-culture and MTT assay.

RESULTS

PBMT with LED light variably promoted hORSC proliferation and suppressed cell apoptosis depending on energy level. LED irradiation induced Wnt5a, Axin2, and Lef1 mRNA expression and β-catenin protein expression in hORSCs. Phosphorylation of ERK, c-Jun, and p38 in hORSCs was observed after LED light irradiation, and ERK inhibitor treatment before irradiation reduced ERK and c-Jun phosphorylation. Red light-treated hORSCs showed substantial increase in IL-6, IL-8, TNF-a, IGF-1, TGF-β1, and VEGF mRNA. Light irradiation at 660 and 830 nm projected onto hORSCs accelerated in vitro migration. LED-irradiated hORSCs increased hDPCs proliferation when they were co-cultured. The conditioned medium from LED-irradiated hORSCs was sufficient to stimulate hDPCs proliferation.

CONCLUSION

These results demonstrate that LED light irradiation induced hORSC proliferation and migration and inhibited apoptosis in vitro. The growth-promoting effects of LEDs on hORSCs appear to be associated with direct stimulation of the Wnt5a/β-catenin and ERK signaling pathway. Lasers Surg. Med. 49:940-947, 2017. © 2017 Wiley Periodicals, Inc.