The Promise of Advanced Laser-Based Therapy

posted by Apollo Lasers on Friday, January 30, 2015

Tomorrow's medicine is here today. Laser therapy is now being commonly used in ORs, orthopedics practices, on athletic fields by athletic trainers, in vet offices, dentists' offices and other practices. Here's an excerpt from a recent article on Biophotonics describing the active role of laser in medicine today.

It started with mouse hairs. In 1967, Dr. Endre Mester of Semmelweis Medical University in Budapest, Hungary, recognized that a low-power ruby laser could stimulate faster hair regrowth in mice. Since then, lasers have increasingly become an important instrument in the physician’s toolbox. 

Today, research is advancing toward the use of lasers to diagnose and treat a plethora of conditions. Recent rapid technological developments in lasers have contributed to their safe and effective use in surgical settings, aesthetic treatments, ophthalmology, oncology, cardiology and many other biomedical applications, including veterinary settings. Growth in cosmetic laser treatments is nothing short of booming: Sales of laser-based instrumentation in the medical and aesthetic sector increased 11 percent from 2012 to 2013 to $682 million, and another 10 percent increase is expected in 2014, to $746 million globally, according to The Worldwide Market for Lasers, a report released in January by Strategies Unlimited. 

Lasers’ efficiency, safety and precision are the drivers behind this growth. 

Low-level laser therapy (LLLT) is one technique in development that uses low-intensity lasers to treat cancer, degeneration, stroke and other conditions. Most LLLT in animals and patients is limited to red and near-IR light at 600-1100 nm; live tissue scatters light at shorter wavelengths and water absorbs too much at wavelengths beyond 1100 nm. Many LLLT devices are Class 3B lasers or LEDs, though some are defocused Class 4 lasers. In most cases, the devices emit divergent beams (uncollimated), delivered with typical irradiance of 5 mW/cm² to 5 W/cm² and low power range of 1 mW to 10 W. Delivery can be pulsed or sometimes continuous, with typical treatment time of 30 to 60 s per treatment point. 

Recent medical research theorizes that the mechanism of low-level laser therapy is primarily via the absorption of light within mitochondria, the numerous “power plants” within cells that convert the oxygen and pyruvate from food into cellular energy via adenosine triphosphate (ATP). As it happens, cytochrome C oxidase, a critical protein involved in the regulation of mitochondrial activity, is a photoacceptor of light in the near- to far-IR. At the cellular level, LLLT displaces nitric oxide from the respiratory chain to increase levels of ATP and reactive oxygen species. The deep-tissue application of laser or LED devices in LLLT techniques may work via this mitochondrial mechanism to promote tissue repair, reduce inflammation and induce analgesia, according to James Carroll, medical researcher, and founder and CEO of Thor Photomedicine in Chesham, England.

Nerve treatment and tooth regeneration in dental and veterinary contexts is a focus of interest in current LLLT research. In February 2014, Carroll and colleagues at the University of Birmingham in England reviewed related dental/orofacial research and found that of 153 papers and studies, 130 of them reported a positive effect in terms of pain relief, healing time or other symptom improvements; 23 reported inconclusive or negative results. The team concluded that direct application of low-power therapeutic light in the oral cavity (as opposed to photodynamic therapies) should be safe and reliable for pain relief in dentistry, as it has been found to be in other health care fields.

Clinical investigator Dr. Praveen Arany and colleagues at Harvard University’s School of Engineering and Applied Sciences have found supporting evidence for this conclusion. The group applied low-power, continuous-wave near-IR laser light (an 810-nm GaAlAs diode with varied power, spot size and distance) to the tooth pulp of treated rats’ teeth and found that this stimulated new growth of dentin, the bonelike substance in teeth (Science Translational Medicine, doi: 10.1126/scitranslmed.3008234).

The mechanism, the researchers said, is the inducement of reactive oxygen species to activate latent transforming growth factor β1 (TGF-β1), which is capable of differentiating human dental stem cells in vitro. They concluded that the laser light already used in dental procedures may encourage tooth regeneration. In fact, researchers agree that LLLT is a safe, effective treatment to enhance healing and tissue remodeling while reducing inflammation and analgesia in a wide range of oral pathologies. Furthermore, the drug-free technique appears to be efficacious where many current pharmaceuticals are not.

In 2012, researchers at the Institute of Ophthalmology at University College London applied LLLT to eye disease. Researcher Dr. Rana Begum and colleagues found that when the retinas of aged mice were exposed to five 90-s exposures of 670-nm light over 35 hours, key inflammatory markers in the mitochondrial membrane were significantly reduced (Neurobiology of Aging, doi:10.1016/j.neurobiolaging.2012.04.014).