Alterted Adipogenesis of Human Mesenchymal Stem Cells by Photobiomodulation Using 1064 nm Laser Light

Biphasic dose response in the anti-inflammation experiment of PBM

Non-invasive laser irradiation can induce photobiomodulation (PBM) effects in cells and tissues, which can help reduce inflammation and pain in several clinical scenarios. The purpose of this study is to review the current literature to verify whether PBM can produce dose effects in anti-inflammatory experiments by summarizing the clinical and experimental effects of different laser parameters of several diseases. The so-called Arndt-Schulz curve is often used to describe two-phase dose reactions, assuming small doses of therapeutic stimulation, medium doses of inhibition, and large doses of killing. In the past decade, more and more attention has been paid to the clinical application of PBM, especially in the field of anti-inflammation, because it represents a non-invasive strategy with few contraindications. Although there are different types of lasers available, their use is adjusted by different parameters. In general, the parameters involved are wavelength, energy density, power output, and radiation time. However, due to the biphasic effect, the scientific and medical communities remain puzzled by the ways in which the application of PBM must be modified depending on its clinical application. This article will discuss these parameter adjustments and will then also briefly introduce two controversial theories of the molecular and cellular mechanisms of PBM. A better understanding of the extent of dualistic dose response in low-intensity laser therapy is necessary to optimize clinical treatment. It also allows us to explore the most dependable mechanism for PBM use and, ultimately, standardize treatment for patients with various diseases.

Effects of photobiomodulation on mitochondrial function in diabetic adipose-derived stem cells in vitro

Herein are reported the effects of photobiomodulation (PBM) on adenosine triphosphate (ATP) and reactive oxygen species (ROS) quantification and mitochondria membrane potential (MMP) of the mitochondria of diabetic adipose-derived stem cells (ADSCs) in vitro. Additionally, the expression of PTEN-induced kinase 1 (PINK1) and RBR E3 ubiquitin-protein ligase (PARKIN) genes, which are involved in mitochondrial quality, were quantified. First, type one diabetes was induced in 10 rats. The rats were then kept for 1 month, after which fat tissue was excised from subcutaneous regions, and stem cells were selected from the fat, characterized as ADSC, and cultivated and increased in elevated sugar conditions in vitro; these samples were considered diabetic-ADSC. Two groups were formed, namely, diabetic-control-ADSC and PBM-diabetic-ADSC. ATP, ROS quantification, and MMP of mitochondria of diabetic ADSCs in vitro were measured, and the expression of PINK1 and Parkin genes was quantified in vitro. The results revealed that PBM significantly increased ATP quantification (p = 0.05) and MMP activity (p = 0.000) in diabetic-ADSCs in vitro compared to the control diabetic-ADSCs; however, it significantly decreased ROS quantification (p = 0.002) and PINK1(p = 0.003) and PARKIN gene expression (p = 0.046) in diabetic-ADSCs. The current findings indicate for the first time that PBM has the potential to maintain the function and quality of mitochondrial diabetic-ADSCs by significantly increasing ATP quantification and MMP activity in diabetic-ADSCs in vitro while significantly decreasing ROS quantification and PINK1 and PARKIN gene expression, making PBM an attractive candidate for use in improving the efficacy of autologous stem cell remedies for diabetic patients with infected diabetic foot ulcers.

Stimulatory responses in α- and β-cells by near-infrared (810 nm) photobiomodulation

Significant efforts have been committed to better understand and regulate insulin secretion as it has direct implications on diabetes. The first phase of biphasic insulin secretion in response to glucose lasts about 10 minutes, followed by a more sustained release persisting several hours. Attenuated insulin release in the first phase is typically associated with abnormal β-cells. While near-infrared photobiomodulation (PBM) demonstrates potential for multiple therapeutic applications, photostimulatory effects on α- and β-cells remain to be further elucidated. Herein, we demonstrate that 810 nm PBM exposure at fluence of 9 J/cm² can elevate the intracellular reactive oxygen species within 15 minutes following photostimulation. In addition, calcium spiking showed an approximately 3-fold increase in both ATC1 (α-cells) and BTC6 (β-cells) and correlates with hormone secretion in response to PBM stimulation. Our findings could lay a foundation for the development of non-biologic therapeutics that can augment islet transplantation.