Transcriptome analysis of the effects of polarized photobiomodulation on human dermal fibroblasts.

BACKGROUND: Photobiomodulation (PBM), the therapeutic use of light, is used to treat a myriad of conditions, including the management of acute and chronic wounds. Despite the presence of clinical evidence surrounding PBM, the fundamental mechanisms underpinning its efficacy remain unclear. There are several properties of light that can be altered in the application of PBM, of these, polarization-the filtering of light into specified plane(s)-is an attractive variable to investigate. AIMS: To evaluate transcriptomic changes in human dermal fibroblasts in response to polarized PBM. RESULTS: A total of 71 Differentially Expressed Genes (DEGs) are described. All DEGs were found in the polarized PBM group (P-PBM), relative to the control group (PC). Of the 71 DEGs, 10 genes were upregulated and 61 were downregulated. Most DEGs were either mitochondrial or extracellular matrix (ECM)-related. Gene Ontology (GO) analysis was then performed using the DEGs from the P-PBM vs. PC group. Within biological processes there were 95 terms found (p < 0.05); in the molecular function there were 18 terms found (p < 0.05); while in the cellular component there were 32 terms enriched (p < 0.05). A KEGG pathways analysis was performed for the DEGs found in the P-PBM vs. PC group. This revealed 21 significantly enriched pathways (p < 0.05). Finally, there were 24 significantly enriched reactome pathways when comparing the DEGs of the P-PBM vs. PC groups (p < 0.05). DISCUSSION AND CONCLUSIONS: The P-PBM DEGs were almost always down regulated compared to the comparator groups. This may be explained by the P-PBM treatment conditions decreasing the amount of cellular stress, hence causing a decreased mitochondria and ECM protective response. Alternatively, it could point to an alternate mechanism, outside the mitochondria, by which PBM exerts its effects. Additionally, PBM appears to have a more widespread effect on the mitochondria than previously thought, opening up many new avenues of investigation in the process.

The effects of polarized photobiomodulation on cellular viability, proliferation, mitochondrial membrane potential and apoptosis in human fibroblasts: Potential applications to wound healing.

Photobiomodulation (PBM) is a widely used therapeutic intervention used to treat several chronic conditions. Despite this, fundamental research underpinning its effectiveness is lacking, highlighted by the lack of a definitive mechanism of action. Additionally, there are many treatment variables which remain underexplored, one of those being the effect of polarization the property of light that specifies the direction of the oscillating electric field. When applied to PBM, using linearly polarized light, when compared to otherwise identical non-polarized light, may enhance its biological efficacy. As such, we investigated the potential biological effects of polarized PBM when compared to non-polarized and non-irradiated controls in the domains of cellular viability, proliferation, apoptosis and mitochondrial membrane potential (ΔΨ) within cells exposed to oxidative stress. It was noted that polarized PBM, when compared to non-polarized PBM and non-irradiated controls, demonstrated mostly increased levels of cellular proliferation and ΔΨ, whilst decreasing the amount of cellular apoptosis. These results indicate that polarization may have utility in the clinical application of PBM. Future research is needed to further elucidate the underpinning mechanisms of PBM and polarization.

The effect of vitamin D supplementation on circulating osteoprogenitor cells: A pilot randomized controlled trial.

Circulating osteoprogenitor (COP) cells are a relatively newly discovered mesenchymal precursors population in the peripheral blood. While some aspects of their physiology have been documented in vitro, little is known about their behavior in vivo. To facilitate understanding regarding their potential role in the management of musculoskeletal disease, more research into how these cells respond to growth factors and hormones in vivo is still required. To this end, we performed a randomized controlled pilot study investigating the effect of vitamin D supplementation on COP cells in healthy older adults. Twenty-two individuals were recruited and stratified through their baseline vitamin D levels into deficient (<35 nmol/L), insufficient (35-49 nmol/L) and sufficient (>50 nmol/L) groups, and then randomized to receive either a 50,000 IU bolus dose of vitamin D, along with a 1000 IU daily supplement for six weeks, or the 1000 IU supplement alone. Participants were assessed at baseline, week three, and week six, with the primary outcome being a change in the number of COP cells. Secondary outcomes were vitamin D, markers of bone formation and resorption, parathyroid hormone, and calcium. The study showed that, independently of the dosing, increasing vitamin D levels led to a concomitant 52% increase in COP cell number (p < 0.001). There were no differences between strata, or any of the secondary outcomes in the trial. This suggests that COP cells are regulated in some way by vitamin D, similar to the bone marrow mesenchymal stem cell. Future studies are needed to evaluate the long-term effects of vitamin D supplementation, and how COP cells may be involved in chronic musculoskeletal disease.

The effects of photobiomodulation on human dermal fibroblasts in vitro: A systematic review.

Photobiomodulation (PBM) is reported to impart a range of clinical benefits, from the healing of chronic wounds to athletic performance enhancement. The increasing prevalence of this therapy conflicts with the lack of understanding concerning specific cellular mechanisms induced by PBM. Herein, we systematically explore the literature base, specifically related to PBM (within the range 600-1070 nm) and its influence on dermal fibroblasts. The existing research in this field is appraised through five areas: cellular proliferation and viability; cellular migration; ATP production and mitochondrial membrane potential; cellular protein expression and synthesis; and gene expression. This review demonstrates that when fibroblasts are irradiated in vitro within a set range of intensities, they exhibit a multitude of positive effects related to the wound healing process. However, the development of an optimal in vitro framework is paramount to improve the reliability and validity of research in this field.

The Impact of Three-Dimensional Printed Anatomical Models on First-Year Student Engagement in a Block Mode Delivery.

Student engagement is known to have several positive effects on learning outcomes and can impact a student's university experience. High levels of engagement in content-heavy subjects can be difficult to attain. Due to a major institutional restructure, the anatomy prosection laboratory time per subject was dramatically reduced. In response, the authors set out to redesign their anatomy units with a focus on engaging the learning activities that would increase time-on-task both within and outside of the classroom. One of these curriculum changes was the implementation of a suite of anatomy learning activities centered on sets of three-dimensional printed upper limb skeleton models. A two-part mixed-method sequential exploratory design was used to evaluate these activities. Part one was a questionnaire that evaluated the students' engagement with and perceptions of the models. Part two involved focus groups interviews, which were an extension of the survey questions in part one. The results of the study indicated that the majority of students found the models to be an engaging resource that helped improve their study habits. As a result, students strongly felt that the use of the models inspired greater academic confidence and overall better performance in their assessments. Overall, the models were an effective way of increasing the engagement and deep learning, and reinforced previous findings from the medical education research. Future research should investigate the effects of these models on student's grades within osteopathy and other allied health courses.

Good, better, best? The effects of polarization on photobiomodulation therapy.

Photobiomodulation therapy (PBMT) is a widely adopted form of phototherapy used to treat many chronic conditions that effect the population at large. The exact physiological mechanisms of PBMT remain unsolved; however, the prevailing theory centres on changes in mitochondrial function. There are many irradiation parameters to consider when investigating PBMT, one of which is the state of polarization. There is some evidence to show that polarization of red and near-infrared light may promote different and/or increased biological activity when compared to otherwise identical non-polarized light. These enhanced cellular effects may also be present when the polarized light is applied linear to the tissue direction. Herein, we synthesize the current experimental and clinical evidence pertaining to polarized photobiomodulation therapy; ultimately, to better inform future research into this area of phototherapy.

Polarized light therapy: Shining a light on the mechanism underlying its immunomodulatory effects.

This study investigates the immunomodulatory effects of polychromatic polarized light therapy (PLT) on human monocyte cells. While there is some evidence demonstrating a clinical effect in the treatment of certain conditions, there is little research into its mechanism of action. Herein, U937 monocyte cells were cultured and exposed to PLT. The cells were then analyzed for change in expression of genes and cell surface markers relating to inflammation. It was noted that 6 hours of PLT reduced the expression of the CD14, MHC I and CD11b receptors, and increased the expression of CD86. It was also shown that PLT caused downregulation of the genes IL1B, CCL2, NLRP3 and NOD1, and upregulation of NFKBIA and TLR9. These findings imply that PLT has the capacity for immunomodulation in human immune cells, possibly exerting an anti-inflammatory effect.