Light-Emitting Diode Photobiomodulation After Cerebral Ischemia

Well fuck, we really need someone to write and distribute a protocol on this. All this previous research; OR ARE WE WAITING FOR SOMEONE ELSE TO SOLVE THE PROBLEM?     

 

A new treatment protocol using photobiomodulation and muscle/bone/joint recovery techniques having a dramatic effect on a stroke patient's recovery: a new weapon for clinicians Sept. 2012      

 

Interplay between up-regulation of cytochrome-c-oxidase and hemoglobin oxygenation induced by near-infrared laser June 2017      

 

Photobiomodulation therapy promotes neurogenesis by improving post-stroke local microenvironment and stimulating neuroprogenitor cells Oct. 2017     

 

The latest here:    

 

Light-Emitting Diode Photobiomodulation After Cerebral Ischemia

Bárbara Argibay¹, Francisco Campos^1*, María Perez-Mato¹, Alba Vieites-Prado¹, Clara Correa-Paz¹, Esteban López-Arias¹, Andrés Da Silva-Candal¹, Vicente Moreno^2,3, Carlos Montero^2,3, Tomás Sobrino¹, José Castillo¹ and Ramón Iglesias-Rey^1*

• ¹Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
• ²Optics Area, Department of Applied Physics, Faculty of Physics, Universitdade de Santiago de Compostela, Santiago de Compostela, Spain
• ³Faculty of Optics and Optometry, Universitdade de Santiago de Compostela, Santiago de Compostela, Spain

Photobiomodulation (PBM) therapy is a promising therapeutic approach for several pathologies, including stroke. The biological effects of PBM for the treatment of cerebral ischemia have previously been explored as a neuroprotective strategy using different light sources, wavelengths, and incident light powers. However, the capability of PBM as a novel alternative therapy to stimulate the recovery of the injured neuronal tissue after ischemic stroke has been poorly explored. The aim of this study was to investigate the low-level light irradiation therapy by using Light Emitting Diodes (LEDs) as potential therapeutic strategy for stroke. The LED photobiomodulation (continuous wave, 830 nm, 0.2–0.6 J/cm²) was firstly evaluated at different energy densities in C17.2 immortalized mouse neural progenitor cell lines, in order to observe if this treatment had any effect on cells, in terms of proliferation and viability. Then, the PBM-LED effect (continuous wave, 830 nm, 0.28 J/cm² at brain cortex) on long-term recovery (12 weeks) was analyzed in ischemic animal model by means lesion reduction, behavioral deficits, and functional magnetic resonance imaging (fMRI). Analysis of cellular proliferation after PBM was significantly increased (1 mW) in all different exposure times used; however, this effect could not be replicated in vivo experimental conditions, as PBM did not show an infarct reduction or functional recovery. Despite the promising therapeutic effect described for PBM, further preclinical studies are necessary to optimize the therapeutic window of this novel therapy, in terms of the mechanism associated to neurorecovery and to reduce the risk of failure in futures clinical trials.

Introduction

Photobiomodulation therapy has been investigated in the past few years as an alternative treatment for stroke and traumatic brain injury (TBI) in order to promote a neuroprotective effect and tissue regeneration (1–5). The main benefits attributed to brain PBM therapy are related to different biological processes such as increasing cerebral metabolic function, stimulating neurogenesis and synaptogenesis, and neuroprotection via anti-inflammatory, and antioxidant biological signaling (5, 6).

In the field of stroke, PBM applied in the acute phase has been suggested as a promising therapeutic approach for inducing functional recovery. Thus, some studies have demonstrated that 808–660 nm Low Level Laser Therapy (LLLT) applied after ischemia on experimental animals improved neurological rating scores without increasing body temperature, by direct illumination of the skin on shaved animals (7–10).

On the other hand, it has been shown that transcranial laser therapy within 24 h from stroke onset is a safe procedure, in terms of mortality or occurrence of adverse effects, when it is used on stroke patients (11, 12). LLLT used alone or combined with the thrombolytic treatment for stroke (recombinant tissue plasminogen activator) did not increase the risk of hemorrhagic transformation (13). Despite experimental evidences and human safety, a clinical trial designed to analyze the beneficial effect near-infrared laser therapy in stroke has showed negative results, in part because many of the parameters used (therapeutic time-window, laser intensity) were not sufficiently optimized for use in animal preclinical studies (14).

Light emitting diodes (LEDs) devices have emerged as an innovative source of brain PBM for a wide range of neurological conditions, and their use has been approved by the US Food and Drugs Administration. Different studies about LED-PBM have been mainly tested on cell in vitro assays (15–18), or in experimental animal studies like retinal alterations (19, 20), and its use in neuronal injures have been even tested in pathologies as TBI and stroke as a neuroprotectant approach, with contradictory results (5, 9, 21).

In this regard, the biological effects of PBM for the treatment of stroke have been widely explored using different light sources, wavelengths, and incident powers in preclinical studies. However, studies were mainly focused on the neuroprotective effects, while neurorecovery processes were evaluated only by functional tests or mortality rate, and the direct effect of PBM on recovery of the damage neuronal tissue was not accurately tested so far. In the field of magnetic resonance imaging (MRI), the interest in functional magnetic resonance imaging (fMRI) has been increasing significantly as a noninvasive tool to evaluate neural activity and the efficacy of neurorecovery therapies (22).

Therefore, to evaluate if LED-PBM could induce any positive effects of on neuronal recovery after stroke, in this study we have studied first the effect of PBM at different energy densities in cell culture, in terms of proliferation and viability. Secondly, we have studied the long-term recovery effect of LED-PBM in an animal model of transient ischemic stroke by means of reduction of ischemic lesion size, and finally we have tested for the first time functional recovery determined by fMRI in combination with functional behavioral tests.