Histochemical analysis of collagen fibers in giant cell fibroma and inflammatory fibrous hyperplasia

Retrospective study of oral lesions biopsied in babies and toddlers

Epidemiological data on the distribution of oral and maxillofacial diseases present in early childhood are scarce in the literature. This study analyzed the frequency of lesions biopsied in this region in children aged 0 to 3 years and sent for histopathological analysis in a reference oral pathology laboratory . Histopathological diagnostic data, lesion location, sex, and age were collected. Of the total of 93,950 records, 250 cases (0.27%) belonged to the age group from 0 to 3 years old. The most frequently diagnosed oral alterations were: mucocele (34/250; 13.6%); papilloma (11/250; 4.4%), giant cell fibroma (6/250; 2.4%), pyogenic granuloma (5/250; 2%) and hemangioma (3/250; 1.2%). The lip was the most affected site, followed by the gingiva and the tongue. These results generate information on the lesions most frequently diagnosed in early childhood, which facilitates the process of diagnosis and, consequently, treatment.

Time course of histopathological changes after bleomycin sclerotherapy in rabbit gallbladders as a model for simple hepatic cysts

Bleomycin sclerotherapy is used in the treatment of cystic lesions; however, the histopathological changes are undefined. Present animal models of cystic diseases are not adequate for the study of sclerotherapy of hepatic cysts, primarily because the established cysts in these models are too small in size. The aim of the present study was to establish a new animal model of simple hepatic cysts, and assess the histopathological changes after bleomycin sclerotherapy. Rabbit gallbladder, with ligaturing of the cholecystic duct whilst preserving cholecystic vessels, was used as a model for simple hepatic cysts. Bleomycin (2 mg dissolved in 1 ml saline) was injected into the aspirated gallbladder, gallbladder tissue was harvested (after 1, 7, 14, 28, 42, 56 and 84 days) and histopathological changes were evaluated (n=4 per group). Additionally, control rabbit gallbladders were injected with 1 ml saline and sampled after 14 days (n=4). Histopathological changes were evaluated using hematoxylin-eosin and Masson's trichrome staining, and immunohistochemistry for CD20-, CD43- and CD68-positive cells was performed. The integrated optical density (IOD) of immunohistochemical staining and average positive stained area percentage (APSAP) of collagen were quantitatively analyzed. The results revealed gallbladders in the control group had regular epithelial cells with no visible inflammation or fibrosis. In the experimental group, epithelial cells were swollen and necrotic on the first day, and were replaced gradually by single-layer flat cells from day 56. Inflammatory infiltration was found in the submucosa, and the IOD of T cells, B cells and macrophages were highest on day 1, and these parameters declined gradually, eventually disappearing. The APSAP of collagen was highest on day 7, and gradually declined thereafter. The results suggest that histopathological changes after bleomycin sclerotherapy of a simple hepatic cyst model were characterized by sequential epithelial destruction, inflammatory cell infiltration, collagen proliferation and epithelial partial regeneration.

Semiautomated quantification of the fibrous tissue response to complex three-dimensional filamentous scaffolds using digital image analysis

Fibrosis represents a relevant response to the implantation of biomaterials, which occurs not only at the tissue-material interface (fibrotic encapsulation) but also within the void fraction of complex three-dimensional (3D) biomaterial constructions (fibrotic ingrowth). Usual evaluation of the biocompatibility mostly depicts fibrosis at the interface of the biomaterial using semiquantitative scores. Here, the relations between encapsulation and infiltrating fibrotic growth are poorly represented. Virtual pathology and digital image analysis provide new strategies to assess fibrosis in a more differentiated way. In this study, we adopted a method previously used to quantify fibrosis in visceral organs to the quantification of fibrosis to 3D biomaterials. In a proof-of-concept study, we transferred the "Collagen Proportionate Area" (CPA) analysis from hepatology to the field of biomaterials. As one task of an experimental animal study, we used CPA analysis to quantify the fibrotic ingrowth into a filamentous scaffold after subcutaneous implantation. We were able to demonstrate that the application of the CPA analysis is well suited as an additional fibrosis evaluation strategy for new biomaterial constructions. The CPA method can contribute to a better understanding of the fibrotic interactions between 3D scaffolds and the host tissue responses.

Benign connective and soft-tissue neoplasms of the oral and maxillofacial region: Cross-sectional study of 1066 histopathological specimens

BACKGROUND

Benign connective and soft-tissue neoplasms (CSTNs) are unusual in the head and neck region. The aim of the present study was to evaluate the demographic and clinicopathological features of these neoplasms.

METHODS

A cross-sectional study was conducted of cases diagnosed as benign CSTNs, with data collected from biopsy records. The chi-square test was used. A p-value <0.05 was considered indicative of statistical significance.

RESULTS

Among the 38 119 specimens, 1066 (2.79%) were benign CSTNs: 369 fibroblastic/myofibroblastic, 250 adipocytic, 179 vascular, 130 neural, 94 osseous/cartilaginous, 19 muscular, and two fibrohistiocytic. Most patients were female (62.8%) and white-skinned (45.8%). Mean age was 42 years. The tongue (25.2%) was the most affected site for extraosseous neoplasms.

CONCLUSION

This study had the largest sample of benign oral and maxillofacial CSTNs. Although these tumors have similar clinical features, the characterization and differentiation detailed here may help clinicians with regards to the correct diagnosis.

The interaction of ceramide 1-phosphate with group IVA cytosolic phospholipase A2 coordinates acute wound healing and repair

The sphingolipid ceramide 1-phosphate (C1P) directly binds to and activates group IVA cytosolic phospholipase A₂ (cPLA₂α) to stimulate the production of eicosanoids. Because eicosanoids are important in wound healing, we examined the repair of skin wounds in knockout (KO) mice lacking cPLA₂α and in knock-in (KI) mice in which endogenous cPLA₂α was replaced with a mutant form having an ablated C1P interaction site. Wound closure rate was not affected in the KO or KI mice, but wound maturation was enhanced in the KI mice compared to that in wild-type controls. Wounds in KI mice displayed increased infiltration of dermal fibroblasts into the wound environment, increased wound tensile strength, and a higher ratio of type I:type III collagen. In vitro, primary dermal fibroblasts (pDFs) from KI mice showed substantially increased collagen deposition and migration velocity compared to pDFs from wild-type and KO mice. KI mice also showed an altered eicosanoid profile of reduced proinflammatory prostaglandins (PGE₂ and TXB₂) and an increased abundance of certain hydroxyeicosatetraenoic acid (HETE) species. Specifically, an increase in 5-HETE enhanced dermal fibroblast migration and collagen deposition. This gain-of-function role for the mutant cPLA₂α was also linked to the relocalization of cPLA₂α and 5-HETE biosynthetic enzymes to the cytoplasm and cytoplasmic vesicles. These findings demonstrate the regulation of key wound-healing mechanisms in vivo by a defined protein-lipid interaction and provide insights into the roles that cPLA₂α and eicosanoids play in orchestrating wound repair.

MMP-1 and MMP-8 expression in giant-cell fibroma and inflammatory fibrous hyperplasia

The aim of this study is to compare the immunoexpression of metalloproteinases 1 and 8 in giant-cell fibroma, inflammatory fibrous hyperplasia and normal mucosa. Twenty-two cases of giant-cell fibroma, inflammatory fibrous hyperplasia and oral mucosa (control) each were subjected to immunohistochemistry using anti-metalloproteinase-1 and anti-metalloproteinase-8 antibodies. Eight images of each case were captured and analysed through the a) application of a count grid to count the number of positive neutrophils, macrophages, lymphocytes, plasma cells, fibroblasts and blood vessels to obtain the percentage of staining and b) semi-automated segmentation quantifying the stained area in square micrometres. Statistical tests included ANOVA Two-way, Kruskal Wallis and Games-Howell, with a significance level of 5%. An increased percentage of metalloproteinase-1-immunopositive blood vessels were observed in giant-cell fibroma (26.6±22.4; p=0.02) and inflammatory fibrous hyperplasia (34.3±31.5; p=0.01) compared with the control group (19.6±9.2). No significant differences in inflammatory cells, fibroblasts and total area of metalloproteinase-1 and -8 were noted among the three groups. Metalloproteinase-1 apparently acts within the pathogenesis of giant-cell fibroma and inflammatory fibrous hyperplasia.