Laser therapy reduces inflammatory cytokines
The therapeutic use of non-invasive, low level (cold) laser and and infrared has not crossed the gap into clinical practice to the degree that the rich body of scientific research justifies. The laser and infrared therapies we use here appear to help even though you can't feel them (at the time of application); but what evidence is there that they really do anything? And by what mechanisms? Consider this study published in the journal Photomedicine and Laser Surgery a few years ago that documents the effect of visible and infrared light on inflammatory cytokines (immune system messenger molecules). The authors state:
"The aim of this randomized, placebo-controlled, double-blind trial was to investigate changes in the content of 10 cytokines in the human peripheral blood after transcutaneous [through the skin] and in vitro [to blood removed from the body] irradiation with polychromatic visible and infrared (IR) polarized light..."
The magnitude of the effect that they observed by just applying the light to the sacral area of the study subjects is surprising:
"A dramatic decrease in the level of pro-inflammatory cytokines TNF-α, IL-6, and IFN-γ was revealed: at 0.5 h after exposure of volunteers (with the initial parameters exceeding the norm), the cytokine contents fell, on average, 34, 12, and 1.5 times. The reduced concentrations of TNF-α and IL-6 were preserved after four daily exposures, whereas levels of IFN-γ and IL-12 decreased five and 15 times. At 0.5 h and at later times, the amount of anti-inflammatory cytokines was found to rise: that of IL-10 rose 2.7–3.5 times (in subjects with normal initial parameters) and of TGF-β1 1.4–1.5 times."
But if you expose just the area over the sacrum, what happens when that blood mixes with the rest of the circulation?
"Similar regularities of the light effects were recorded after in vitro irradiation of blood, as well as on mixing the irradiated and non-irradiated autologous blood at a volume ratio 1:10 (i.e., at modeling the events in a vascular bed of the exposed person when a small amount of the transcutaneously photomodified blood contacts its main circulating volume)."
In other words, a small limited application causes system-wide effects. Considering how much we need therapies that physiologically modulate the inflammatory response without side effects, the authors' conclusion is extremely compelling:
"Exposure of a small area of the human body to light leads to a fast decrease in the elevated pro-inflammatory cytokine plasma content and to an increase in the the anti-inflammatory factor concentration, which may be an important mechanism of the anti-inflammatory effect of phototherapy. These changes result from transcutaneous photomodification of a small volume of blood and a fast transfer of the light-induced changes to the entire pool of circulating blood [!]."
Here's a little more from the large body of research published in the same journal:
- LLLT can modulate inflammatory processes in a dose-dependent manner and can be titrated to significantly reduce acute inflammatory pain in clinical settings.
- Laser therapy was effective in preventing and treating oral effects induced by radiotherapy and chemotherapy, thus improving the patient's quality of life.
- LLLT reduces inflammatory signs (more effectively than LED) in arthritis.
- Salivary levels of inflammatory cytokines TNF-α and IL-6 are reduced in patients with stomatitis (mouth sores).
By the way, this is interesting in connection with the earlier post on the infrared treatment of depression.