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

Mast Cells as a Factor in Regulation of Breast Cancer Stromal Component Associated with Breast Cancer Aggressiveness

BACKGROUND

It has been proven that changes in the morphology, representation, and organization of collagen fibers contribute to the formation of a unique microenvironment, which is associated with the metastatic potential of malignant neoplasms due to the initiation of cell migration and changes in polarization. Among the modulators of the collagen stroma, fibroblasts remain the most widely studied today. At the same time, much less attention is focused on the study of immune cells in the tumor microenvironment, in particular, mast cells (MCs).

AIM

To investigate the relationship between the MCs status and the features of the collagen matrix of breast cancer (BCa).

MATERIALS AND METHODS

The study was conducted on the postoperative material of 78 patients with BCa stage I-II. MCs were assessed by a histochemical method using toluidine blue. For estimation of the functional activity of MCs, a degranulation index was calculated. COL1A1, COL3A1, and MMP-9 expression in tumor tissue was assessed immunohistochemically. A visualization of collagen fibers was performed using the staining by Malory. Microphotographs were pre-processed in Adobe Photoshop SS 2019 and analyzed using the software packages CurveAlign v. 4.0 and ImageJ.

RESULTS

Tumor tissue with a high density and functional activity of MCs was characterized by an increased expression of COL1A1 (p < 0.05), COL3A1 (p < 0.05), and MMP-9 (p < 0.05). In BCa tissue with the lower MCs degranulation index, collagen fibers become thicker (p < 0.05), shorter (p < 0.05), and denser (p < 0.05). At the same time, the existence of a relationship between the levels of miR-155-5p and the expression of COL1A1 (r = 0.703, p = 0.009), COL3A1 (r = 0.603, p = 0.043), and MMP-9 in tumor cells (r = 0.562, p = 0.039) and in the stroma (r = 0.546, p = 0.038), as well as the associations of the levels of this miRNA with the fiber length (r = -0.632, p = 0.013), width (r = -0.522, p = 0.048), and density (r = 0.699, p = 0.014) were found. Significantly higher rates of miR-155-5p expression (p < 0.05) were recorded in BCa tissue with a high index of MCs degranulation.

CONCLUSION

During the BCa progression, the role of MCs in the manifestation of the tumor development increases. A growing number of infiltrated MCs contributes to the activation of MMP and fibrillar collagen expression. These changes lead to increased remodeling of the tumor stroma, which is directly reflected in the spatial organization of the collagen matrix. The increased activity of proteases causes a decrease in the length and width of fibrils, which is explained by a decrease in the number of mature fibers and their disorganization in three-dimensional space. The obtained data allow us to assert that MCs play a key role not only in the formation of a specific immune microenvironment of BCa but also in determining the direction of changes in the tumor stroma, which promotes cancer aggressiveness.

Exploring the role of granzyme B in subretinal fibrosis of age-related macular degeneration

Age-related macular degeneration (AMD), a prevalent and progressive degenerative disease of the macula, is the leading cause of blindness in elderly individuals in developed countries. The advanced stages include neovascular AMD (nAMD), characterized by choroidal neovascularization (CNV), leading to subretinal fibrosis and permanent vision loss. Despite the efficacy of anti-vascular endothelial growth factor (VEGF) therapy in stabilizing or improving vision in nAMD, the development of subretinal fibrosis following CNV remains a significant concern. In this review, we explore multifaceted aspects of subretinal fibrosis in nAMD, focusing on its clinical manifestations, risk factors, and underlying pathophysiology. We also outline the potential sources of myofibroblast precursors and inflammatory mechanisms underlying their recruitment and transdifferentiation. Special attention is given to the potential role of mast cells in CNV and subretinal fibrosis, with a focus on putative mast cell mediators, tryptase and granzyme B. We summarize our findings on the role of GzmB in CNV and speculate how GzmB may be involved in the pathological transition from CNV to subretinal fibrosis in nAMD. Finally, we discuss the advantages and drawbacks of animal models of subretinal fibrosis and pinpoint potential therapeutic targets for subretinal fibrosis.

Effects of Violet and IR LED Light on mast cell degranulation: in vivo study in a murine model

The aim of this study was to evaluate the influence of IR (λ850 ± 10 nm) and violet (λ405 ± 10 nm) LED phototherapy on total mast cells counts and its ability to influence mast cell degranulation. For this, 27 Wistar rats were used and were randomly distributed into three groups: control, IR LED, and violet LED. When indicated, irradiation done and they were sacrificed, had their tongue removed immediately, 20-min, 45-min, and 2-h after irradiation. Samples were processed to wax, cut, and stained with Toluidine Blue. Intact and degranulated mast cells were counted under light microscopy, and statistical analysis was carried out. In the superficial connective tissue and muscular tissues, violet LED light caused a significant increase in both total number and degranulated mast cells when compared to the control group immediately after irradiation. The degranulation indexes were higher in the groups irradiated with Violet light, both in superficial connective tissue and muscular tissues in relation to the timing. Irradiation with IR LED caused immediate increase in the total number and degranulated of mast cells when compared to the control group only in the superficial connective tissue. In all times observed, the highest total amount of mast cells was seen immediately after irradiation, except in the muscular tissue, which presented the highest amount after 20-min. It was concluded that IR and violet LED light were able to increase the number of mast cells and inducing degranulation in oral mucosa. However, considering that violet LED light can be harmful in periodontal disease, it seems that the use of IR LED light could be the best option in Dentistry.

Innovative biomaterials for the treatment of periodontal disease

Periodontitis is a multifactorial disease that involves the destruction of hard and soft tissues surrounding the tooth. Routine periodontal treatment includes mechanical debridement (surgical and non-surgical) and the systemic administration of antibiotics. In contrast, severe and chronic periodontitis involves aggressive tissue destruction and bone resorption, and the damage is usually irreversible. In these severe cases, bone grafts, the delivery of growth hormones, and guided tissue regeneration can all be used to stimulate periodontal regeneration. However, these approaches do not result in consistent and predictable treatment outcomes. As a result, advanced biomaterials have evolved as an adjunctive approach to improve clinical performance. These novel biomaterials are designed to either prolong the release of antibacterial agents or osteogenic molecules, or to act as immunomodulators to promote healing. The first half of this review briefly summarizes the key immune cells and their underlying cellular pathways implicated in periodontitis. Advanced biomaterials designed to promote periodontal regeneration will be highlighted in the second half. Finally, the limitations of the current experimental design and the challenges of translational science will be discussed.

Expression and degranulation of mast cells in laser photobiomodulated mucositis chemo-induced: pilot study in hamsters

This study aimed to evaluate the influence of laser photobiomodulation on the expression and degranulation of mast cells in chemo-induced oral mucositis (OM) lesions in hamsters. Twelve adult male Syrian hamsters (Mesocricetus auratus), golden lineage, were submitted to OM induction. They were divided into three groups: control-OM without treatment (C), OM treated with red laser (RL), OM treated with infrared laser (IL) and analyzed in the experimental time of 7 days. Three and 4 days after the intraperitoneal injection of the chemotherapy drug fluorouracil, the OM lesions were induced by making grooves in the right cheek pouch. Immediately after chemoinduction, the hamsters were submitted to photobiomodulation every 48 h for 7 days. The specimens were processed and stained using the hematoxylin-eosin and toluidine blue techniques. There was a predominance of mild chronic inflammation in the experimental groups and a greater persistence of neutrophils in the control group (C), although not statistically significant. The group irradiated with red laser (RL) had the highest mean mast cell expression (38.28 ± 19.05) (p < 0.001). As for the degranulation activity in mast cells, the control group (C) showed a greater number of fields with more than 50% of degranulated cells, presenting statistical significance when comparing it with the RL (p < 0.009) and IL (p = 0.036) group. It can be concluded that photobiomodulation, at both wavelengths, decreased mast cell degranulation, accelerating the inflammatory process. The use of infrared laser provided, in addition to less degranulation, the quantitative reduction of mast cells.

Immunomodulation in the Treatment of Periodontitis: Progress and Perspectives

Periodontitis is one of the most common dental diseases. Compared with healthy periodontal tissues, the immune microenvironment plays the key role in periodontitis by allowing the invasion of pathogens. It is possible that modulating the immune microenvironment can supplement traditional treatments and may even promote periodontal regeneration by using stem cells, bacteria, etc. New anti-inflammatory therapies can enhance the generation of a viable local immune microenvironment and promote cell homing and tissue formation, thereby achieving higher levels of immune regulation and tissue repair. We screened recent studies to summarize the advances of the immunomodulatory treatments for periodontitis in the aspects of drug therapy, microbial therapy, stem cell therapy, gene therapy and other therapies. In addition, we included the changes of immune cells and cytokines in the immune microenvironment of periodontitis in the section of drug therapy so as to make it clearer how the treatments took effects accordingly. In the future, more research needs to be done to improve immunotherapy methods and understand the risks and long-term efficacy of these methods in periodontitis.

A New Target Organ of Leishmania (Viannia) braziliensis Chronic Infection: The Intestine

Leishmania (Viannia) braziliensis is one of the main causes of cutaneous leishmaniasis in the Americas. This species presents genetic polymorphism that can cause destructive lesions in oral, nasal, and oropharyngeal tracts. In a previous study, the parasite caused several histopathological changes to hamster ileums. Our study evaluates immune response components, morphological changes, and effects on neurons in the ileums of hamsters infected by three different strains of L. (V.) braziliensis in two infection periods. For the experiment, we separated hamsters into four groups: a control group and three infected groups. Infected hamsters were euthanized 90- or 120-days post infection. We used three strains of L. (V.) braziliensis: the reference MHOM/BR/1975/M2903 and two strains isolated from patients who had different responses to Glucantime^® treatment (MHOM/BR/2003/2314 and MHOM/BR/2000/1655). After laparotomy, ileums were collected for histological processing, biochemical analysis, and evaluation of neurons in the myenteric and submucosal plexuses of the enteric nervous system (ENS). The results demonstrated the increase of blood leukocytes after the infection. Optical microscopy analysis showed histopathological changes with inflammatory infiltrates, edemas, ganglionitis, and Leishmania amastigotes in the ileums of infected hamsters. We observed changes in the organ histoarchitecture of infected hamsters when compared to control groups, such as thicker muscular and submucosa layers, deeper and wider crypts, and taller and broader villi. The number of intraepithelial lymphocytes and TGF-β-immunoreactive cells increased in all infected groups when compared to the control groups. Mast cells increased with longer infection periods. The infection also caused remodeling of intestinal collagen and morphometry of myenteric and submucosal plexus neurons; but this effect was dependent on infection duration. Our results show that L. (V.) braziliensis infection caused time-dependent alterations in hamster ileums. This was demonstrated by the reduction of inflammatory cells and the increase of tissue regeneration factors at 120 days of infection. The infected groups demonstrated different profiles in organ histoarchitecture, migration of immune cells, and morphometry of ENS neurons. These findings suggest that the small intestine (or at least the ileum) is a target organ for L. (V.) braziliensis infection, as the infection caused changes that were dependent on duration and strain.

Treatment with Luteolin Improves Lipopolysaccharide-Induced Periodontal Diseases in Rats

Periodontitis is a dental disease that produces the progressive destruction of the bone surrounding the tooth. Especially, lipopolysaccharide (LPS) is involved in the deterioration of the alveolar bone, inducing the release of pro-inflammatory mediators, which cause periodontal tissue inflammation. Luteolin (Lut), a molecule of natural origin present in a large variety of fruits and vegetables, possess beneficial properties for human health. On this basis, we investigated the anti-inflammatory properties of Lut in a model of periodontitis induced by LPS in rats. Animal model predicted a single intragingival injection of LPS (10 μg/μL) derived from Salmonella typhimurium. Lut administration, was performed daily at different doses (10, 30, and 100 mg/kg, orally), starting from 1 h after the injection of LPS. After 14 days, the animals were sacrificed, and their gums were processed for biochemical analysis and histological examinations. Results showed that Lut (30 and 100 mg/kg) was equally able to reduce alveolar bone loss, tissue damage, and neutrophilic infiltration. Moreover, Lut treatment reduced the concentration of collagen fibers, mast cells degranulation, and NF-κB activation, as well as the presence of pro-inflammatory enzymes and cytokines. Therefore, Lut implementation could represent valid support in the pharmacological strategy for periodontitis, thus improving the well-being of the oral cavity.