Do laser and led phototherapies influence mast cells and myofibroblasts to produce collagen?

Chronic Sclerosing Sialadenitis of the Submandibular Gland and its Histopathological Spectrum in the IgG4-Related Disease: a Series of 17 Cases

PURPOSE

This study aimed to characterize the histopathological immunohistochemical features of chronic sclerosing sialadenitis, emphasizing the IgG4-related disease.

METHODS

Seventeen cases of chronic sclerosing sialoadenitis were examined for histopathological aspects, (inflammation, fibrosis, glandular parenchyma, and lymphoid follicles) and immunohistochemistry (BCL2, CD3, CD20, CD34, CD163, p63, cyclin D1, mast cell, SMA, S100A4, IgG, and IgG4) which were scored. IgG4-related disease features were investigated. Demographic and clinical data were also collected.

RESULTS

Males predominated (10:7), with an average lesion size of 3.9 cm. Common histopathological findings included reduced acinar parenchyma, lymphoid follicle formation, and ductular proliferation. CD3-positive T lymphocytes and CD34- and SMA-positive stromal fibroblasts were abundant. Nine cases (53%) showed sialoliths and three cases met the criteria for IgG4-related disease.

CONCLUSION

CSS of the submandibular gland represents a reactive pattern rather than IgG4-RD as only 3 cases seemed to be related to IgG4-RD. The immunohistochemical profile revealed an abundant population of CD3-positive T lymphocytes, as opposed to regulatory proteins such as cyclin D1, demonstrating that populations of CD34- and SMA-positive stromal fibroblasts contribute to the fibrosis characteristic of CSS. In addition, our results provide a comprehensive insight into the study of CSS and its relationship with IgG4-RD.

Effectiveness of low level laser therapy versus cryotherapy in cancer patients with oral mucositis: Systematic review and network meta-analysis

OBJECTIVE

The purpose of this network meta-analysis was to analyze the relative effects of low level laser therapy (LLLT) and/or cryotherapy in cancer patients with oral mucositis (OM).

METHODS

This literature search followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), and the Physiotherapy Evidence Database (PEDro) up to 2020. Only randomized control trials which involved comparisons of groups receiving the interventions of combined cryotherapy and LLLT, LLLT, cryotherapy and usual care (the control group) in patients with cancer were eligible for inclusion. The effect sizes are presented as odds ratios for the occurrence of severe, moderate and none/mild OM. The mixed treatment comparison was conducted using generalized linear mixed models to analyze the direct and indirect comparisons of interventions. The critical appraisal was assessed using Cochrane Collaboration's tool. Heterogeneity between studies was assessed using I² statistics, and publication bias was evaluated by constructing a funnel plot.

RESULTS

Twenty-six randomized controlled trials with a total enrollment of 1830 cancer patients with OM were included. The outcome of none/mild OM is desirable, and odds ratios of more than 1 favor the intervention group. Moderate and severe OM are defined as adverse outcomes, and ORs less than 1 favor the intervention group. The treatment effects of the combined cryotherapy and LLLT were better than those of usual care for none/mild and severe OM (ORs = 106.23 [95% CI = 12.15 to 929.17] and 0.01 [95% CI = 0 to 0.57], respectively). Treatment effects with cryotherapy alone and LLLT alone were better than those with usual care for none/mild and severe OM (ORs = 3.13 [95%CI = 1.56 to 6.27]; ORs = 7.56 [95%CI = 3.84 to 14.88] and 0.25 [95%CI = 0.11 to 0.54]; ORs = 0.13 [95%CI = 0.07 to 0.24], respectively). Nevertheless, for patients with none/mild OM, treatment effects with combined use of cryotherapy and LLLT were better than those with only LLT or cryotherapy (ORs = 14.06 [95%CI = 1.79 to 110.30] and 33.95 [95%CI = 3.50 to 329.65], respectively). For patients with moderate OM, treatment effect did not reach statistical significance among comparisons. The limitations include the wide variability in treatment protocols and the non-uniform outcome measurements across the studies examined.

CONCLUSION

Compared with no intervention, the treatment effects of combined cryotherapy and LLLT, laser alone, and cryotherapy alone are beneficial for the reduction of severe OM. There is no difference in treatment effects among cryotherapy and/or LLLT intervention in cancer patients with moderate OM. Results of this study provide an implicative basis for LLLT and cryotherapy as viable interventions that can significantly improve severe OM.

In Vitro Evidences of Different Fibroblast Morpho-Functional Responses to Red, Near-Infrared and Violet-Blue Photobiomodulation: Clues for Addressing Wound Healing

Although photobiomodulation (PBM) has proven promising to treat wounds, the lack of univocal guidelines and of a thorough understanding of light–tissue interactions hampers its mainstream adoption for wound healing promotion. This study compared murine and human fibroblast responses to PBM by red (635 ± 5 nm), near-infrared (NIR, 808 ± 1 nm), and violet-blue (405 ± 5 nm) light (0.4 J/cm2 energy density, 13 mW/cm2 power density). Cell viability was not altered by PBM treatments. Light and confocal laser scanning microscopy and biochemical analyses showed, in red PBM irradiated cells: F-actin assembly reduction, up-regulated expression of Ki67 proliferation marker and of vinculin in focal adhesions, type-1 collagen down-regulation, matrix metalloproteinase-2 and metalloproteinase-9 expression/functionality increase concomitant to their inhibitors (TIMP-1 and TIMP-2) decrease. Violet-blue and even more NIR PBM stimulated collagen expression/deposition and, likely, cell differentiation towards (proto)myofibroblast phenotype. Indeed, these cells exhibited a higher polygonal surface area, stress fiber-like structures, increased vinculin- and phospho-focal adhesion kinase-rich clusters and α-smooth muscle actin. This study may provide the experimental groundwork to support red, NIR, and violet-blue PBM as potential options to promote proliferative and matrix remodeling/maturation phases of wound healing, targeting fibroblasts, and to suggest the use of combined PBM treatments in the wound management setting.

Besides Photothermal Effects, Low-Level CO2 Laser Irradiation Can Potentiate Skin Microcirculation Through Photobiomodulation Mechanisms

Background: Improvement of microcirculation is one of the important mechanisms of low-level laser therapy (LLLT) to treat some diseases such as wound healing. Most previous studies have been carried out with multiple lasers other than the 10,600-nm CO₂ laser. Recently, the CO₂ laser has been used not only as a tool for excision of soft tissues but also for therapeutic applications. Objective: To study whether low-level CO₂ laser irradiation can influence microcirculation and further explore the underlying mechanisms. Methods: Seventy-milliwatt (70-mW) CO₂ lasers irradiated the forearms of 12 participants and skin blood perfusion (SkBP) was measured with a laser speckle imager. The thermal effect of irradiation was evaluated by measuring the irradiated skin in vivo and the exposed cell suspensions in vitro. Extracellular adenosine triphosphate (eATP) of the human mast cell line (HMC-1) is assessed by luciferin-luciferase assay to explore the potential mechanisms. Results: Irradiation caused dose-dependent increase in SkBP. At a medium dose of 262 J/cm², SkBP reached its maximum value at 195.8% ± 18.6% of the baseline (n = 12, p < 0.01). Such laser irradiation had a mild thermal effect, heating local skin temperature (SkT) by 6.1°C ± 0.3°C (n = 10) and warming cell suspensions by 4.5°C ± 0.8°C (n = 6). Irradiation dose-dependently lowered eATP levels of HMC-1 cells in vitro. At a medium dose of 262 J/cm², eATP levels declined to the minimum at 74.8% ± 5.5% of the baseline (n = 12, p < 0.01). This downregulation effect could be significantly inhibited by 100-μM ARL67156, a nonspecific ecto-ATPase inhibitor. On the contrary, heating itself slightly raised the level of eATP. Conclusions: Low-level CO₂ laser irradiation can improve microcirculation. Besides the thermal effect, regulation of extravascular eATP by the photobiomodulation mechanism may be involved. This implies that CO₂ lasers might be used in LLLT.

Photobiomodulation: lasers vs. light emitting diodes?

Photobiomodulation (PBM) is a treatment method based on research findings showing that irradiation with certain wavelengths of red or near-infrared light has been shown to produce a range of physiological effects in cells, tissues, animals and humans. Scientific research into PBM was initially started in the late 1960s by utilizing the newly invented (1960) lasers, and the therapy rapidly became known as "low-level laser therapy". It was mainly used for wound healing and reduction of pain and inflammation. Despite other light sources being available during the first 40 years of PBM research, lasers remained by far the most commonly employed device, and in fact, some authors insisted that lasers were essential to the therapeutic benefit. Collimated, coherent, highly monochromatic beams with the possibility of high power densities were considered preferable. However in recent years, non-coherent light sources such as light-emitting diodes (LEDs) and broad-band lamps have become common. Advantages of LEDs include no laser safety considerations, ease of home use, ability to irradiate a large area of tissue at once, possibility of wearable devices, and much lower cost per mW. LED photobiomodulation is here to stay.

Photobiomodulation: lasers vs. light emitting diodes?

Photobiomodulation (PBM) is a treatment method based on research findings showing that irradiation with certain wavelengths of red or near-infrared light has been shown to produce a range of physiological effects in cells, tissues, animals and humans. Scientific research into PBM was initially started in the late 1960s by utilizing the newly invented (1960) lasers, and the therapy rapidly became known as "low-level laser therapy". It was mainly used for wound healing and reduction of pain and inflammation. Despite other light sources being available during the first 40 years of PBM research, lasers remained by far the most commonly employed device, and in fact, some authors insisted that lasers were essential to the therapeutic benefit. Collimated, coherent, highly monochromatic beams with the possibility of high power densities were considered preferable. However in recent years, non-coherent light sources such as light-emitting diodes (LEDs) and broad-band lamps have become common. Advantages of LEDs include no laser safety considerations, ease of home use, ability to irradiate a large area of tissue at once, possibility of wearable devices, and much lower cost per mW. LED photobiomodulation is here to stay.

Should open excisions and sutured incisions be treated differently? A review and meta-analysis of animal wound models following low-level laser therapy

Although low-level laser therapy (LLLT) was discovered already in the 1960s of the twentieth century, it took almost 40 years to be widely used in clinical dermatology/surgery. It has been demonstrated that LLLT is able to increase collagen production/wound stiffness and/or improve wound contraction. In this review, we investigated whether open and sutured wounds should be treated with different LLLT parameters. A PubMed search was performed to identify controlled studies with LLLT applied to wounded animals (sutured incisions-tensile strength measurement and open excisions-area measurement). Final score random effects meta-analyses were conducted. Nineteen studies were included. The overall result of the tensile strength analysis (eight studies) was significantly in favor of LLLT (SMD = 1.06, 95% CI 0.66-1.46), and better results were seen with 30-79 mW/cm² infrared laser (SMD = 1.44, 95% CI 0.67-2.21) and 139-281 mW/cm² red laser (SMD = 1.52, 95% CI 0.54-2.49). The overall result of the wound contraction analysis (11 studies) was significantly in favor of LLLT (SMD = 0.99, 95% CI 0.38-1.59), and the best results were seen with 53-300 mW/cm² infrared laser (SMD = 1.18, 95% CI 0.41-1.94) and 25-90 mW/cm² red laser (SMD = 1.6, 95% CI 0.27-2.93). Whereas 1-15 mW/cm² red laser had a moderately positive effect on sutured wounds, 2-4 mW/cm² red laser did not accelerate healing of open wounds. LLLT appears effective in the treatment of sutured and open wounds. Statistical heterogeneity indicates that the tensile strength development of sutured wounds is more dependent on laser power density compared to the contraction rate of open wounds.

Association Between Mast Cells and Collagen Maturation in Chronic Periodontitis in Humans

Mast cells (MCs) can influence the maturation of collagen fibers. This study evaluated the relationship between the distribution and degranulation of MCs and collagen maturation in human gingival tissue in chronic periodontitis. A total of 16 specimens of patients clinically diagnosed as periodontitis and 18 controls clinically diagnosed as healthy or gingivitis were included. Immunohistochemistry and Picrosirius staining were performed to identify MCs and assess collagen fibers, respectively. Chi-square, t test, and Pearson's correlation test ( p<0.05) were used. In control specimens, there was a positive association between MCs in the connective tissue and the presence of immature collagen ( p=0.001); in periodontitis samples, this association was not confirmed ( p≥0.12). There was no significant relationship between periodontal diagnosis and collagen maturation or MC degranulation ( p≥0.35). MC density was significantly higher ( p=0.04) in periodontitis tissue (339.01 ± 188.94 MCs/mm²) than in control tissue (211.14 ± 131.13 MCs/mm²) in the area of connective tissue containing inflammatory infiltrate. There was a correlation between the number of MCs and probing depth ( r = 0.34, p=0.04). MCs are involved in the pathogenesis of periodontal diseases and might be associated with collagen maturation in periodontal tissue during the early stages of periodontal disease pathogenesis.

Does laser phototherapy influence the proliferation of myoepithelial cells in the salivary gland of hypothyroid rats?

Thyroid hormones influence both development and growth of organs and tissues and guarantee metabolic demands that interfere with the quality of digestive secretions, including those of the salivary glands. Laser phototherapy - LPT can modulate various biological phenomena and its diverse effects permit the action on different cell types. The aim of this study was to evaluate the influence of laser phototherapy on myoepithelial cells of salivary glands of hypothyroid rats. Forty-two albino Wistar rats were divided into two main groups: euthyroid (EU) and hypothyroid (HYPO). Hypothyroidism was induced using propylthiouracil (PTU) for 4weeks. Each group was divided into subgroups: control (without laser) and laser groups (Red/infrared - IR). LPT was used on the submandibular gland and was carried out using a diode laser (λ660 or λ780nm, 40mW, spot size 0.04cm², irradiation area 1cm², 300s, 6J/cm² per gland, 12J/cm² per session) and started two weeks after PTU treatment. LPT was repeated every other day for two weeks. After animal death, the glands were removed, dissected and processed for immunohistochemical analysis. It was observed an increase in the number of myoepithelial cells of hypothyroid control rats in comparison to euthyroid controls (p=0.001). Visible LPT (λ660nm) caused significant higher proliferation of myoepithelial cells in EU rats when compared to IR LPT (λ 780nm)(p≤0.001).It is concluded that, despite the LPT protocol used did not influence myoepithelial proliferation on hypothyroid rats it significantly increased the proliferation on euthyroid animals.

Myofibroblasts and mast cells: influences on biological behavior of odontogenic lesions

Odontogenic lesions differ in their rate of recurrence and aggressiveness. This study aimed to evaluate the presence of myofibroblasts and mast cells in odontogenic lesions. Sample consisted of 20 cases each of dentigerous cysts, odontogenic keratocysts, and solid ameloblastomas. Histologic sections were submitted to immunohistochemistry using anti-α-smooth muscle actin and anti-tryptase antibodies. Myofibroblasts and mast cells were counted at ×400 magnification in 5 and 10 fields, respectively. Myofibroblasts were more frequent in ameloblastomas (24.41), followed by odontogenic keratocysts (16.21) and dentigerous cysts (11.85; P=.002). Granulated and degranulated mast cells were more frequent in dentigerous cysts (7.88 and 8.96, respectively), followed by odontogenic keratocysts (6.53 and 7.08) and ameloblastomas (5.21 and 1.88). The difference was only significant for degranulated mast cells (P<.05). Analysis of the correlation between myofibroblasts and mast cells (granulated and degranulated) revealed a moderate positive correlation only in ameloblastomas (R=0.621, P=.003). Probably, myofibroblasts are related to the biological behavior of the odontogenic lesions studied, particularly their aggressiveness. On the other hand, mast cells seem to be associated with inflammatory processes, which are more frequent in cystic lesions than in benign neoplasms. In addition, mast cells may induce the differentiation of fibroblasts into myofibroblasts, thus increasing the number of the latter.

Thymol accelerates the recovery of the skeletal muscle of mice injured with cardiotoxin

OBJECTIVES

The aim of this study was to investigate the preventive effect of thymol in in vivo muscle inflammation and regeneration on cardiotoxin-induced injury.

METHODS

Mice were pretreated (p.o.) with thymol (10-100 mg/kg), and after 1 h, cardiotoxin (25 μM, 40 μl) was administrated into the gastrocnemius muscle. The quantification of the areas of inflammation and regeneration of muscle tissue (3, 7 and 10 days) in HE-stained slides as well as the count of total mast cells and different phenotypes of mast cells were made. Sirius red staining was used to analyse total collagen expression.

KEY FINDINGS

The pretreatment with thymol significantly reduced the area of inflammation (30 and 100 mg/kg) and increased the area of regeneration (100 mg/kg) 3 days after the cardiotoxin injection. Thymol at 30 and 100 mg/kg increased the area of collagen in 3 days and also decreased this area in 7 and 10 days, compared to the injured group. The pretreatment with thymol did not affect the number of total mast cells; however, it was able to change the number of mucosal mast cells within 10 days.

CONCLUSIONS

This study suggests that thymol ameliorates inflammatory response and accelerates regeneration in cardiotoxin-induced muscle injury.

Interaction of stromal and microvascular components in keratocystic odontogenic tumors

OBJECTIVE

Little is known about the interaction of stromal components in odontogenic tumors. Thus, the aim of this study was to investigate mast cells (MCs), myofibroblasts, macrophages, and their possible association with angiogenesis and lymphangiogenesis in keratocystic odontogenic tumors (KCOTs).

MATERIAL AND METHODS

Thirty cases of KCOTs were included and analyzed by immunohistochemistry for mast cell tryptase, α-SMA, CD34, CD163, and D240. For comparative purpose, 15 radicular cysts (CRs) and 7 pericoronal follicles (PFs) were included.

RESULTS

There was an increase in MCs for RCs and this difference was significant when they were compared to KCOTS and PFs. A significant increase in the density of MFs was observed for KCOTs when compared to RCs and PFs (P = 0.00). No significant difference in CD163-positive macrophages (P = 0.084) and CD34-positive vessels (P = 0.244) densities was observed between KCOTs, RCs, and PFs, although KCOTs showed a higher density of all proteins. Significant difference in lymphatic vessel density was observed for KCOTs when compared to RCs and PFs (P = 0.00). Positive correlation was observed between mast cell tryptase and CD34 in KCOTs (P = 0.025).

CONCLUSIONS

A significant interaction between the MC population and CD34-positive vessels in KCOTs supported the hypothesis that MCs and blood vessels contribute to the stromal scaffold of KCOT.

Cellulite: an evidence-based review

BACKGROUND

Cellulite is a multifactorial condition that is present in 80-90 % of post-pubertal women. Despite its high prevalence, it remains a major cosmetic concern for women. A wide range of products and treatments for cellulite reduction is available; however, no systematic review has been performed so far to evaluate the efficacy of the available treatment options for cellulite.

OBJECTIVE

The objective of this review is to provide a systematic evaluation of the scientific evidence of the efficacy of treatments for cellulite reduction.

METHODS

This systematic review followed the PRISMA guidelines for reporting systematic reviews and meta-analyses. Only original articles in English or German reporting data on the efficacy of cellulite treatments from in vivo human studies were considered. In total, 67 articles were analyzed for the following information: therapy, presence of a control group, randomization, blinding, sample size, description of statistical methods, results, and level of evidence.

RESULTS

Most of the evaluated studies, including laser- and light-based modalities, radiofrequency, and others had important methodological flaws; some did not use cellulite severity as an endpoint or did not provide sufficient statistical analyses. Of the 67 studies analyzed in this review, only 19 were placebo-controlled studies with randomization. Some evidence for potential benefit was only seen for acoustic wave therapy (AWT) and the 1440 nm Nd:YAG minimally invasive laser.

CONCLUSION

This article provides a systematic evaluation of the scientific evidence of the efficacy of treatment for cellulite reduction. No clear evidence of good efficacy could be identified in any of the evaluated cellulite treatments.

Oral crest lengthening for increasing removable denture retention by means of CO2 laser

The loss of teeth and their replacement by artificial denture is associated with many problems. The denture needs a certain amount of ridge height to give it retention and a long-term function. Crest lengthening procedures are performed to provide a better anatomic environment and to create proper supporting structures for more stability and retention of the denture. The purpose of our study is to describe and evaluate the effectiveness of CO₂ laser-assisted surgery in patients treated for crest lengthening (vestibular deepening). There have been various surgical techniques described in order to restore alveolar ridge height by pushing muscles attaching of the jaws. Most of these techniques cause postoperative complications such as edemas, hemorrhage, pain, infection, slow healing, and rebound to initial position. Our clinical study describes the treatment planning and clinical steps for the crest lengthening with the use of CO₂ laser beam (6–15 Watts in noncontact, energy density range: 84.92–212.31 J/cm², focus, and continuous mode with a focal point diameter of 0.3 mm). At the end of each surgery, dentures were temporarily relined with a soft material. Patients were asked to mandatorily wear their relined denture for a minimum of 4–6 weeks and to remove it for hygienic purposes. At the end of each surgery, the deepest length of the vestibule was measured by the operator. No sutures were made and bloodless wounds healed in second intention without grafts. Results pointed out the efficiency of the procedure using CO₂ laser. At 8 weeks of post-op, the mean of crest lengthening was stable without rebound. Only a loss of 15% was noticed. To conclude, the use of CO₂ laser is an effective option for crest lengthening.