The Essential Role of Light-Induced Autophagy in the Inner Choroid/Outer Retinal Neurovascular Unit in Baseline Conditions and Degeneration

The present article discusses the role of light in altering autophagy, both within the outer retina (retinal pigment epithelium, RPE, and the outer segment of photoreceptors) and the inner choroid (Bruch's membrane, BM, endothelial cells and the pericytes of choriocapillaris, CC). Here autophagy is needed to maintain the high metabolic requirements and to provide the specific physiological activity sub-serving the process of vision. Activation or inhibition of autophagy within RPE strongly depends on light exposure and it is concomitant with activation or inhibition of the outer segment of the photoreceptors. This also recruits CC, which provides blood flow and metabolic substrates. Thus, the inner choroid and outer retina are mutually dependent and their activity is orchestrated by light exposure in order to cope with metabolic demand. This is tuned by the autophagy status, which works as a sort of pivot in the cross-talk within the inner choroid/outer retina neurovascular unit. In degenerative conditions, and mostly during age-related macular degeneration (AMD), autophagy dysfunction occurs in this area to induce cell loss and extracellular aggregates. Therefore, a detailed analysis of the autophagy status encompassing CC, RPE and interposed BM is key to understanding the fine anatomy and altered biochemistry which underlie the onset and progression of AMD.

The Role of Low-Level Laser Therapy in Bone Healing: Systematic Review

Low-level laser therapy (LLLT) is a treatment that is increasingly used in orthopedics practices. In vivo and in vitro studies have shown that low-level laser therapy (LLLT) promotes angiogenesis, fracture healing and osteogenic differentiation of stem cells. However, the underlying mechanisms during bone formation remain largely unknown. Factors such as wavelength, energy density, irradiation and frequency of LLLT can influence the cellular mechanisms. Moreover, the effects of LLLT are different according to cell types treated. This review aims to summarize the current knowledge of the molecular pathways activated by LLLT and its effects on the bone healing process. A better understanding of the cellular mechanisms activated by LLLT can improve its clinical application.

Accelerated Canine Retraction by Using Mini Implant With Low-Intensity Laser Therapy

Background The continuous increase in demand for reduced treatment times has led researchers to think in terms of "accelerated orthodontics." Generally, the duration for fixed orthodontic treatment is around two to three years. Prolonged use of braces leads to external root resorption, a high risk of caries, and decreased patient compliance. Therefore, finding an optimal supplementary approach to achieve faster tooth movement is still considered a subject of interest. Low-intensity laser therapy (LILT) is one of the non-invasive surgical techniques in the field of accelerated orthodontics. Low-level laser therapy (LLLT) has demonstrated faster healing, less bleeding, and biostimulation and anti-inflammatory effects. According to all studies, it accelerates tooth movement, thereby reducing braces treatment time. It is simple, safe, and minimally invasive. Despite these pieces of evidence, studies have shown variable findings in low-level laser therapy. This study evaluates the effect of LLLT on accelerated orthodontics in comparison with conventional canine retraction. An aluminum gallium arsenide-type diode laser with a wavelength of 940 nm has been used in this study. Methodology This study was conducted using the split-mouth method, which included 20 patients with permanent dentition who required first premolar extractions. A miniscrew implant was placed on both the right and left sides for maximum anchorage. Irradiation doses were applied on days 0, 3, 7, and 14 of the first month. Subsequently, irradiations were given every 15 days until the canine's retraction was complete in the test group. Results The study results three months after the canine retraction in the test and control groups (M1) were 0.81 ± 0.03 mm/month and 0.74 ± 0.04 mm/month, respectively, indicating a significantly higher rate of canine retraction in the test group than in the control group (P < 0.0001). The average increase in the amount of tooth movement at three months was 40.1% and 36.3% in the test and control groups, respectively. However, the average increase in the amount of movement of teeth following canine retraction was 100% in the test group and 68.2% in the control group. There were significant variations in the pain score between Day 1 and Day 3 (P = 0.003) in the test group; however, there was no analytic variation in the pain score between Day 1 and Day 30 in the test group (P = 0.18). The pain score between Day 3 and Day 30 was significantly lower. Conclusions It was concluded that the rate of canine retraction increases when it is combined with LILT-assisted accelerated orthodontics in comparison to conventional canine retraction. Although LLLT does not provide immediate pain relief, it relieves the sensation of pain after 24-72 hours. LILT is an innovative, non-invasive technique that allows rapid orthodontic tooth movement. The rate of canine retraction increases when it is combined with LILT-assisted accelerated orthodontics in comparison to conventional canine retraction using mini-implants.

Effects of Photo-Biomodulation in Stargardt Disease

Purpose

Stargardt disease (STGD1) is the most common hereditary macular degeneration and currently no treatments have been approved to interrupt the progression of the disease. The aim of this study was to evaluate the efficacy of photo-biomodulation in patients with Stargardt disease 1 year after treatment, considering as primary outcomes improvements in best corrected visual acuity (BCVA), microperimetry, and pattern electroretinography (PERG) amplitude.

Materials and Methods

Ninety eyes of 45 patients with a diagnosis of Stargardt disease stage 1 were prospectively recruited at the University of Bologna. Selected patients were treated with photo-biomodulation therapy for 1 year for 10 minutes a day, twice a day, and 5 days per week for 12 months. A light emitting diode (LED) of 10 Hz and wavelength 650 nm was used. BCVA and microperimetry were assessed before treatment and 1 year after photo-biomodulation, whereas PERG was assessed at baseline, 1, 3, 6, and 12 months after treatment.

Results

BCVA improved from 0.7 [interquartile range (IQR)=0.6-0.9)] to 0.4 (IQR=0.2-0.5)] after treatment (95% CI=-0.3, -0.35; p=<0.001) and PERG negative wave at 35 ms (N35)-positive wave at 50 ms (P50) amplitude improved from 0.9 (IQR=0.74-1.21) to 2.12 (95% CI=1.11, 1.28; p<0.001). MP-1 Microperimetry improved from 26.5% (IQR=16.75-40) of median preferred retinal loci (PRL) within an area of 2° of diameter to 38% (IQR=29-50.25; 95% CI=10.50, 14.50; p=<0.001); on the other hand, PRL within 4° of diameter raised from 72% (IQR=51.5-80) to 80% (IQR=76-87) after photo-biomodulation (95% CI=4.50, 7.50; p<0.001). Also, patients with an improvement of more than 1.205 PERG N35-P50 ratio amplitude at 3 months and more than 1.29 at 6 months tended to present an improvement of more than 0.2 logMar in BCVA at 12 months (p=0.28, AUC=0.630; p=0.30, AUC=0.636).

Conclusion

BCVA, PERG, and MP-1 significantly improved 1 year after treatment. Also, improvement of PERG N35-P50 amplitude at 3 and 6 months was correlated to BCVA improvement at 1 year, suggesting that PERG could be useful in predicting visual outcome after photo-biomodulation.

Visible light and human skin pigmentation: The importance of skin phototype

Melanin is synthesised within melanocytes and transferred to keratinocytes in human skin, thereby regulating skin colour and protecting skin cells against UVR-induced damage. We commonly divide human skin into six phototypes (SPT)-I to -VI (Fitzpatrick scale) according to the skin's tanning response to UVR. In this pilot study, we investigated the impact of UVR (maximum 311nm), blue (peak 450nm) and green visible light (peak 530nm) on melanin production and type in healthy human skin histocultures (SPT-I, -II and -III). UVR, blue and green light stimulated a surface tanning response in SPT-II and -III, but not SPT-I. Using the Warthin-Starry stain for sensitive melanin detection, all three light treatments induced melanogenesis in SPT-II and -III skin. Surprisingly, blue and green light (but not UVR) stimulated melanin synthesis in SPT-I skin. Moreover, melanin synthesis induced by blue and green visible light in SPT-I, SPT-II, and SPT-III skin was not associated with a detectable increase in DNA damage or cell apoptosis. By contrast, both responses were detected after UVR. These data suggest that blue and green visible light can stimulate melanin production in fair-skinned individuals without, at least some of, the harmful consequences of UVR-induced pigmentation. We are currently examining the molecular basis of UVR-independent melanogenesis in fair skin.

Low-level red plus near infrared lights combination induces expressions of collagen and elastin in human skin in vitro

OBJECTIVE

Light therapy has attracted medical interests as a safe, alternative treatment for photo-ageing and photo-damaged skin. Recent research suggested the therapeutic activity of red and infrared (IR) lights may be effective at much lower energy levels than those used clinically. This study was to evaluate the efficacy of low-level red plus near IR light emitting diode (LED) combination on collagen and elastin and ATP production.

METHODS

Human dermal fibroblasts or skin tissues were irradiated daily by red (640 nm) plus near IR (830 nm) LED lights combination at 0.5 mW/cm² for 10 minutes (0.3 J/cm² ). qPCR, ELISAs or histology were used to determine the gene and protein expressions. Fluorescent measurement was used to assess crosslinks of collagen and elastic fibres. ATP production was evaluated by ATP assay.

RESULTS

Treatment of human fibroblast cell cultures with low-level red plus near IR lights combination was found to significantly increase LOXL1, ELN and COL1A1 and COL3A1 gene expressions as well as the synthesis of the procollagen type I and elastin proteins. Treating human skin explants with low-level red plus near IR lights combination similarly induced significant increases in the same gene expressions, type III collagen and elastic fibre formation and crosslinks. ATP production was increased in human dermal fibroblasts after red plus near IR lights combination treatment.

CONCLUSION

Low-level red plus near IR lights combination stimulated the production of collagen and elastin production associated with anti-ageing benefits. These findings suggest that low-level red plus near IR LED light combination may provide an effective treatment opportunity for people with photo-aged skin.

Human Oral Motion-Powered Smart Dental Implant (SDI) for In Situ Ambulatory Photo-biomodulation Therapy

Peri-implant disease is an inflammatory condition affecting the soft and hard tissues surrounding a dental implant. However, current preventative methods are insufficient due to the limited bioactivity on the dental implant and poor patient compliance. Recently, photo-biomodulation (PBM) therapy that can recover and regenerate peri-implant soft tissue has attracted considerable attention in dentistry. In this paper, a seamless human oral motion-powered dental implant system (called Smart Dental Implant or SDI) is presented as an ambulatory PBM therapy modality. SDI allows the in situ light delivery, which is enabled by the energy harvesting from dynamic human oral motions (chewing and brushing) via an engineered piezoelectric dental crown, an associated circuit, and micro light emitting diodes (LEDs). The SDI also offers adequate mechanical strength as the clinical standards. Using primary human gingival keratinocytes (HGKs) as a model host organism and Pseudomonas aeruginosa lipopolysaccharides (LPS) as a model inflammatory stimulus, effective SDI-mediated PBM therapy is demonstrated. A new class of dental implants could be an ambulatory PBM therapy platform for the prevention of peri-implant disease without patient dependency, warranting long-lasting dental implants.

Photonic Therapy in Periodontal Diseases an Overview with Appraisal of the Literature and Reasoned Treatment Recommendations

Recent reviews and meta-analyses of the literature over the past quarter-century have failed to provide enough evidence to prove or disprove the actual utility of photonic therapy in periodontitis, alone or adjunctive to conventional approaches. This apparent paradox has been explained by the many physical, molecular, biological, anatomical, and technical variables of photonic treatments, which can differ in light-emitting devices (laser or LED), wavelengths, irradiation power and modes, clinical objectives, follow-up times, disease grading, and assessment methods. This multi-faceted, controversial scenario has led practitioners to underestimate the actual potential of photonic therapy in periodontal diseases. In this critical appraisal of the literature, we have briefly summarized the main photonic therapies and instruments used in Periodontology, highlighting their main characteristics and limitations. Then, we have tried to identify and discuss the key methodological issues which can have an impact on the outcome of photonic therapies. Our main goal was to identify the best parameters, settings, and methodologies to perform effective periodontal photonic treatments and to extrapolate some recommendations for clinical use. Should these recommendations find a consensus among periodontologists and be adopted in future clinical studies, they will hopefully contribute to dissipate the present confusion and uncertainty on this complex matter.