Dose and time-response effect of photobiomodulation therapy on glycemic control in type 2 diabetic patients combined or not with hypoglycemic medicine: A randomized, crossover, double-blind, sham-controlled trial

The effects of different doses of single- and dual-wavelength whole-body photobiomodulation on metabolic parameters in obese mice

Photobiomodulation (PBM) shows beneficial effects on obesity-related alterations. It is not known if dual- is more beneficial than single-wavelength, nor the dose-response effect of such treatments. The effects of different doses of single- and dual-wavelength whole-body PBM on metabolic parameters in obese mice were evaluated. Male Swiss albino mice were fed with standard (Chow) or a cafeteria (CAF) diet and allocated into Sham (lights off), and PBM (whole-body blanket (140 cm2) composed of 20 LED clusters, 2.14 mW/cm2/cluster, for 67 or 133 s: 1 or 2 J per cluster; 20 and 40 J total energy; and 0.143 and 0.286 J/cm2) with 660 nm (660), 850 (850) nm, or 660 nm + 850 nm (660/850). CAF induced insulin resistance that was inhibited in 660-1, 660-2, 850-1, and 660/850-2. CAF increased serum total cholesterol that was inhibited in 660-1, 660-2, 850-1, 660/850-1, and 660/850-2. There were no PBM-induced changes in other variables assessed. The effects of whole-body PBM in metabolic paraments in obese mice were wavelength and dose dependent: increasing the dose for 660 did not affect the outcomes; increasing the dose for 850 negatively affected the outcomes, and increasing the dose for 660/850 was mostly beneficial on the outcomes.

Photobiomodulation for diabetes and its complications: a review of general presentation, mechanisms and efficacy

Diabetes mellitus is a metabolic disease that is marked by persistent hyperglycemia due to inadequate insulin secretion or insulin resistance. Its prevalence is increasing yearly. Diabetes mellitus can lead to serious health complications that are the primary cause of mortality and disability among diabetic patients, including diabetic retinopathy, diabetic foot ulcers, diabetic peripheral neuropathy, and diabetic periodontitis, and so on. Traditional treatments for diabetes and its complications still suffer from limited clinical efficacy and high therapeutic side effects. Photobiomodulation (PBM), which utilizes low levels of red or near-infrared laser to irradiate cells and tissues, has been shown to be efficacious for a wide range of organ damage. In this study, we focus on the application of PBM in diabetes and its complications and mechanisms, as well as the advantages, disadvantages with the aim of developing new ideas for the application of PBM.

The dose-effect response of combined red and infrared photobiomodulation on insulin resistance in skeletal muscle cells

Obesity is a major public health problem and is a major contributor to the development of insulin resistance. In previous studies we observed that single-wavelength red or infrared photobiomodulation (PBM) improved insulin signaling in adipocytes and skeletal muscle of mice fed a high-fat diet, but information about the combination of different wavelengths, as well as the effect of different light doses (J/cm2) is lacking. Therefore, the aim of this study was to investigate the effects of different doses of dual-wavelength PBM on insulin signaling in muscle cell, and explore potential mechanisms involved. Mouse myoblasts (C2C12) were differentiated into myotubes and cultured in palmitic acid, sodium oleate and l-carnitine (PAL) to induce insulin resistance high or in glucose medium (CTRL). Then, they received SHAM treatment (lights off, 0 J/cm2) or PBM (660 + 850 nm; 2, 4 or 8 J/cm2). PAL induced insulin resistance (assessed by Akt phosphorylation at ser473), attenuated maximal citrate synthase activity, and increased the phosphorylation of c-Jun NH(2) terminal kinase (JNK) (T183/Y185). PBM at doses of 4 or 8 J/cm2 reversed these PAL-induced responses. Furthermore, at doses of 2, 4 or 8 J/cm2, PBM reversed the increase in mitofusin-2 content induced by PAL. In conclusion, the combination of dual-wavelength red and infrared PBM at doses of 4 and 8 J/cm2 improved intracellular insulin signaling in musculoskeletal cells, and this effect appears to involve the modulation of mitochondrial function and the attenuation of the activation of stress kinases.

Long-term safety of photobiomodulation exposure to beta cell line and rat islets in vitro and in vivo

This study evaluates the safety and potential benefits of PBM on pancreatic beta cells and islets. PBM was applied to insulin-secreting cell lines (MIN6) and rat pancreatic islets using a 670 nm light source, continuous output, with a power density of 2.8 mW/cm², from 5 s to several 24 h. Measure of cell viability, insulin secretion, mitochondrial function, ATP content, and cellular respiration were assessed. Additionally, a diabetic rat model is used for islet transplantation (pre-conditioning with PBM or not) experiments. Short and long-term PBM exposure did not affect beta cell islets viability, insulin secretion nor ATP content. While short-term PBM (2 h) increases superoxide ion content, this was not observed for long exposure (24 h). Mitochondrial respirations were slightly decreased after PBM. In the islet transplantation model, both pre-illuminated and non-illuminated islets improved metabolic control in diabetic rats with a safety profile regarding the post-transplantation period. In summary, for the first time, long-term PBM exhibited safety in terms of cell viability, insulin secretion, energetic profiles in vitro, and post-transplantation period in vivo. Further investigation is warranted to explore PBM's protective effects under conditions of stress, aiding in the development of innovative approaches for cellular therapy.

Photobiomodulation Enhances the Effect of Strength Training on Insulin Resistance Regardless of Exercise Volume in Mice Fed a High-Fat Diet

The aim was to investigate the effects of different volumes of strength training (ST) in association with photobiomodulation (PBMt) in mice fed a high-fat diet (HFD) on insulin resistance (IR). Male Swiss albino mice were fed HFD and performed high- or low-volume (one-third) ST (3 days/week), associated with PBMt (660 nm + 850 nm; ~42 J delivered) or not (lights off). ST improved IR, lowered visceral adiposity and circulating cytokines, and increased skeletal muscle hypertrophy and mitochondrial activity. The smaller volume of ST did not interfere with the improvement in IR, mitochondrial activity, or inflammatory profile, but exerted a smaller effect on visceral adiposity and skeletal muscle hypertrophy. Association with PBMt further improved IR, regardless of ST volume, although it did not affect adiposity, mitochondrial activity, and the inflammatory profile. Interestingly, PBMt positively affected quadriceps, but attenuated gluteus maximus hypertrophy. The association with PBMt induced greater improvement than ST alone.

Photobiomodulation therapy (red/NIR LEDs) reduced the length of stay in intensive care unit and improved muscle function: A randomized, triple-blind, and sham-controlled trial

CONTEXT

Photobiomodulation therapy (PBMT) has been widely used to improve strength, fatigue resistance and increase muscle mass in healthy individuals. These effects could help critically ill patients admitted to intensive care units (ICUs) who show reduced mobility and muscle strength. ICU-acquired weakness lessens overall health and increases the patient's length of stay in the ICU.

OBJECTIVE

This study evaluated the effects of PBMT using low intensity light-emitting diodes (LEDs) on the mobility and muscle strength (functional capacity) and length of stay of patients admitted to hospital ICU.

METHODS

This randomized, triple-blind, sham-controlled trial was conducted in a hospital ICU. Sixty patients were randomly assigned to two equal groups: (a) PBMT and (b) Sham. PBMT was applied daily to patients until their discharge from the ICU, using a flexible neoprene array of 264 LEDs (120 at 635 nm, 1.2 mW each; 144 at 880 nm, 15 mW each) for 90s (207.36 Joules) at each site. Ten sites were located bilaterally on the thighs, legs, arms, and forearms ventrally and dorsally, 15 min totaling 2,073.6 Joules per session. Outcomes were length of stay (in h) until discharge from the ICU, muscle strength by the Medical Research Council (MRC) score and handgrip dynamometry (HGD), patient mobility by Intensive Care Unit Mobility Scale (IMS) and the Simplified Acute Physiology Score 3 (SAPS 3) for predicting mortality of patients admitted to the ICU.

RESULTS

PBMT reduced the average length of stay in the ICU by ~30% (p = 0.028); increased mobility (IMS: 255% vs. 110% p = 0.007), increased muscle strength (MRC: 12% vs. -9% p = 0.001) and HGD (34% vs. -13% p < 0.001), and the SAPS3 score was similar (p > 0.05).

CONCLUSION

The results suggest that daily PBMT can reduce the length of stay of ICU patients and increase muscle strength and mobility.

Diabetes in spotlight: current knowledge and perspectives of photobiomodulation utilization

Introduction

Diabetes is a global health concern characterized by chronic hyperglycemia resulting from insulinopenia and/or insulin resistance. The rising prevalence of diabetes and its associated complications (ulcers, periodontitis, healing of bone defect, neuropathy, retinopathy, cardiopathy and nephropathy) necessitate innovative therapeutic approaches. Photobiomodulation (PBM), involves exposing tissues and cells to low-energy light radiation, leading to biological effects, largely via mitochondrial activation.

Methods

This review evaluates preclinical and clinical studies exploring the potential of PBM in diabetes and its complications, as well all clinical trials, both planned and completed, available on ClinicalTrials database.

Results

This review highlights the variability in PBM parameters across studies, hindering consensus on optimal protocols. Standardization of treatment parameters and rigorous clinical trials are needed to unlock PBM's full therapeutic potential. 87 clinical trials were identified that investigated PBM in diabetes mellitus (with 5,837 patients planned to be treated with PBM). Clinical trials assessing PBM effects on diabetic neuropathy revealed pain reduction and potential quality of life improvement. Studies focusing on wound healing indicated encouraging results, with PBM enhancing angiogenesis, fibroblast proliferation, and collagen density. PBM's impact on diabetic retinopathy remains inconclusive however, requiring further investigation. In glycemic control, PBM exhibits positive effects on metabolic parameters, including glucose tolerance and insulin resistance.

Conclusion

Clinical studies have reported PBM-induced reductions in fasting and postprandial glycemia without an increased hypoglycemic risk. This impact of PBM may be related to its effects on the beta cells and islets in the pancreas. Notwithstanding challenges, PBM emerges as a promising adjunctive therapy for managing diabetic neuropathy, wound healing, and glycemic control. Further investigation into its impact on diabetic retinopathy and muscle recovery is warranted.