Effect of laser therapy on expression of angio- and fibrogenic factors, and cytokine concentrations during the healing process of human pressure ulcers

Abstract

Objective: To evaluate the effect of laser irradiation at different wavelengths on the expression of selected growth factors and inflammatory mediators at particular stages of the wound healing process.Methods: Sixty-seven patients were recruited, treated, and analyzed (group A - 940 nm: 17 patients; group B - 808 nm: 18 patients; group C - 658 nm: 16 patients; group D - sham therapy: 17 patients). Patients received a basic treatment, including repositioning and mobilization, air pressure mattress and bed support surfaces, wound cleansing and drug therapy. Additionally, patients received laser therapy once a day, 5 times a week for 1 month in use of a semiconductor lasers (GaAlAs) which emitted a continuous radiation emission at separate wavelengths of 940 nm (group A), 808 nm (group B) and 658 nm (group C). In group D (sham therapy), laser therapy was applied in the same manner, but the device was off during each session (only the applicator was switched on to scan pressure ulcers using none coherent red visible light).Results: The positive changes in the measured serum (IL-2, IL-6 and TNF-α) and wound tissue (TNF-α, VEGF and TGFβ1) parameters appeared to be connected only with the wavelength of 658 nm. The significant change in pro-inflammatory mediator levels [interleukin 2 (IL-2) with p=0.008 and interleukin 6 (IL-6) with p=0.016] was noticed after two weeks of laser therapy. In the other groups, the inflammation was also reduced, but the process was not as marked as in group C. Similarly, in the case of tumor necrosis factor (TNF-α) concentration, where after two weeks of treatment with irradiation at a wavelength of 658 nm, a rapid suppression was observed (p=0.001), whereas in the other groups, these results were much slower and not as obvious. Interestingly, again in the case of group C, the change in TNF-α concentration in wound tissue was most intensive (≈75% reduction), whereas the changes in other groups were not as obvious (≈50% reduction). After irradiation (658 nm), the VEGF expression increased significantly within the first two weeks, and then it decreased and maintained a stable level. In contrast, the TGFβ1 activity remained level, but always higher in comparison to other groupsConclusions: The effective healing of pressure ulcers is connected with laser irradiation at a wavelength of 658 nm. We believe that this effect is related to the inhibition of inflammatory processes in the wound and stimulation of angiogenesis and fibroblast proliferation at this specific radiation (based both on concentration of interleukins and TNF-α serum level and VEGF, TGFβ1, TNF-α activities in wound biopsies). Laser therapy at wavelengths of 940 and 808 nm does not significantly affect the above-mentioned repair processes, which explains its low effectiveness in the treatment of pressure ulcers.

Experimental Study of the Effect of Photobiomodulation Therapy on the Regulation of the Healing Process of Chronic Wounds

“…There are a limited number of studies in the literature demonstrating the effect of PBM therapy on IL-6 levels in cutaneous pathology. The increase in the levels of this cytokine in the early stages of wound healing, demonstrated by Mo et al [34], and the decrease in IL-6 concentrations after 14 and 30 days of treatment for pressure ulcers, shown by Taradaj et al [35], do not coincide with our data. This is probably due to the difference in wound models and the studied parameters (local or systemic levels), as well as the parameters of the applied PBM therapy.…”

Effects of Low Level Laser Therapy (LLLT) on Serum Values of Interleukin 6 (IL-6) in Patients with Periodontitis and Type 2 Diabetes Mellitus (T2DM)

“…In recent years, the interest in the use of laser therapy has increased gradually, although there is still heterogeneity in research data and findings, the justification for their application has been unequivocally confirmed ( 36 ). Our findings agree with the findings of Boschi ( 14 , 37 , 38 ). Identical to the values obtained after applying LLLT (In GaAlP, 660 nm) in the study, the values of IL-6 and TNF-α 37 were significantly reduced.…”

Combination of laser and human adipose-derived stem cells in repair of rabbit anal sphincter injury: a new therapeutic approach

“…Therefore, like many other articles on muscle repair [54–56], we used a 660-nm laser. The reason for the selection of the 660-nm wavelength is optimum efficacy in inflammatory processes, angiogenesis, fibroblast proliferation, and cytokine secretion, while such effects are not observed at higher wavelengths (940 and 808 nm) [57].…”