Luis Eduardo Almeida

Apoptosis in displaced temporomandibular joint disc with and without reduction: an immunohistochemical study

Internal derangement (ID) of the temporomandibular joint (TMJ) is due to an abnormal relationship of the articular disc to the mandibular condyle, glenoid fossa and articular eminence. The two most common types of internal derangement are anterior disc displacement with (ADDwR) and without reduction (ADDwoR). Disc displacement is associated with degenerative tissue changes. The histological features of discs from patients with TMJ ID reflect a general remodelling caused by abnormal loading. A correlation has been demonstrated between TMJ ID and apoptosis. Few investigations have addressed the role of apoptosis or caspase activity in TMJ ID. The apoptosis activation process was studied in different areas of discs from 18 patients with ID (both ADDwR and ADDwoR) and four cadavers (controls), with emphasis on the expression of caspase 3, whose activation makes the death process irreversible. The results showed a greater proportion of caspase 3-positive cells in ADDwR and ADDwoR than in control discs. Immunopositivity also varied between disc areas; in particular, in ADDwoR sections labelled cells were significantly more numerous (P < 0.01) in the posterior disc attachment than in the anterior and intermediate bands. In addition, a significantly greater proportion of labelled cells was seen in the anterior (+) and intermediate (++) band of ADDwR compared with ADDwoR discs both bands (P < 0.05). These data suggest the importance of programmed cell death in the progression of TMJ ID.

A current overview of materials and strategies for potential use in maxillofacial tissue regeneration.

Tissue regeneration is rapidly evolving to treat anomalies in the entire human body. The production of biodegradable, customizable scaffolds to achieve this clinical aim is dependent on the interdisciplinary collaboration among clinicians, bioengineers and materials scientists. While bone grafts and varying reconstructive procedures have been traditionally used for maxillofacial defects, the goal of this review is to provide insight on all materials involved in the progressing utilization of the tissue engineering approach to yield successful treatment outcomes for both hard and soft tissues. In vitro and in vivo studies that have demonstrated the restoration of bone and cartilage tissue with different scaffold material types, stem cells and growth factors show promise in regenerative treatment interventions for maxillofacial defects. The repair of the temporomandibular joint (TMJ) disc and mandibular bone were discussed extensively in the report, supported by evidence of regeneration of the same tissue types in different medical capacities. Furthermore, in addition to the thorough explanation of polymeric, ceramic, and composite scaffolds, this review includes the application of biodegradable metallic scaffolds for regeneration of hard tissue. The purpose of compiling all the relevant information in this review is to lay the foundation for future investigation in materials used in scaffold synthesis in the realm of oral and maxillofacial surgery.

Apoptosis in temporomandibular joint disc with internal derangement involves mitochondrial-dependent pathways. An in vivo study

Abstract Objective. Two main apoptosis pathways have been identified: an extrinsic (or death receptor-mediated) and an intrinsic (or mitochondrial) pathway. Apoptotic cell death through the extrinsic pathway has just been described in temporomandibular joint disc (TMJ) with internal derangement (ID); in contrast, no data are available on the involvement of the intrinsic pathway in this tissue. The aim of this work was to investigate whether the intrinsic pathway participates in apoptosis activation in patients with TMJ ID and anterior disc displacement without reduction. Materials and methods. Apoptosis activation was studied in TMJ discs from 15 patients with ID and in six unaffected discs using bcl-2–associated X protein (bax), B-cell lymphoma 2 (bcl-2), cytochrome c and caspase 9 immunohistochemistry. A correlation was sought between immunohistochemical findings and degree of disc damage. Results. None of the pathological TMJ disc sections were immunopositive for bcl-2; negative bcl-2 immunostaining was detected in affected discs; cytochrome c and caspase 9 immunoreactivity was greater in pathological compared to unaffected discs; the difference was significant and correlated with histopathological degeneration score data (Spearmans rho = 0.617). Conclusion. The present findings suggest that in-human TMJ with ID and anterior disc displacement without reduction of cell apoptosis occurs, at least partly, via the mitochondrial pathway, which contributes to the subsequent disc degeneration. These data may have clinical implications and could help devise improved treatment strategies.

Expression and localization of aquaporin-1 in temporomandibular joint disc with internal derangement

BACKGROUND Internal derangement is the most frequent arthropathy affecting the temporomandibular joint, where its commonest form is anterior disc displacement with or without reduction. Despite the frequency of the disorder, the biochemical features of displaced discs are still unclear. METHODS We investigated the expression pattern and localization of aquaporin-1, an important channel protein involved in plasma membrane water permeability, in patients with anterior disc displacement (both with and without reduction), with a view to assessing the characteristics of local tissue responses to the microenvironmental changes induced by abnormal mechanical loading of the displaced disc. Protein expression was studied by immunohistochemistry in different areas of discs from 18 patients with anterior disc displacement with or without reduction and in four normal controls. RESULTS A greater proportion of cells immunopositive for aquaporin-1 were detected in diseased than in normal discs. Whereas protein expression was substantially similar in the different areas of normal discs, a significantly larger number of immunopositive cells were detected in the posterior band of displaced discs without reduction and in the anterior and intermediate bands of those with reduction. CONCLUSIONS These findings suggest that aquaporin-1 is expressed and upregulated in temporomandibular joint with anterior disc displacement (both with and without reduction).

Tumor necrosis factor-related apoptosis-inducing ligand expression correlates to temporomandibular joint disk degeneration.

This study investigated if tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) immunohistochemical expression in human temporomandibular joint (TMJ)-degenerated disks correlates to the degree of tissue damage to elucidate the possible involvement of this apoptotic pathway in TMJ disk degeneration. Twenty-one TMJ displaced disk from 12 patients were affected by anterior disk displacement with reduction and 9 by anterior disk displacement without reduction processed immunohistochemically with TRAIL antibody. Histopathologic grading of the disk degeneration was carried out in each specimen. The mean histopathologic score of the TMJ degenerated disks was 4.77 ± 1.26 (minimum, 2; maximum, 7). Immunolabeling for TRAIL was detected in the cytoplasm of the TMJ disk cells in every sample, although with different patterns of reactivity. The degree of TRAIL immunostaining was correlated to the histopathologic degeneration score obtained from the sample (Spearman &rgr; = 0.617). Therefore, cell loss due to the involvement of TRAIL apoptotic pathway seems, in part, responsible for TMJ disk degeneration.

Immunohistochemical expression of matrix metalloprotease‐2 and matrix metalloprotease‐9 in the disks of patients with temporomandibular joint dysfunction

PURPOSE Matrix metalloproteases (MMPs) are tissue-remodeling enzymes that function during the remodeling process, such as in immune-inflammatory diseases. Metalloprotease-2 (MMP-2) and metalloprotease-9 (MMP-9) are gelatinases that degrade several types of extracellular matrix collagen. It is hypothesized that in temporomandibular joint (TMJ) dysfunction, MMP-2 and MMP-9 expression levels may be elevated. Therefore, the objective of this study is to determine the association of MMP-2 and MMP-9 expression with temporomandibular joint dysfunction using an immunohistochemical approach to evaluate the joint disk. MATERIAL AND METHODS A total of 45 human temporomandibular joint samples were collected, with 36 samples in the test group (patients with anterior disk displacement with reduction (n = 29) and without reduction (n = 7)) and nine samples in the control group. The immunostaining of the TMJ disks was statistically compared between the groups (P < 0.05). RESULTS There was a statistically significant difference for the area of MMP-2 immunostaining between the control group and the displacement disks with reduction group (ADDwR) (P = 0.048) and between the groups with disk displacement and without reduction (ADDwoR) (P = 0.029). The expression of MMP-2 was significantly elevated in the ADDwoR group. CONCLUSION No statistically significant difference was found between the variable area of MMP-9 expression in the disk with and without disk displacement, as determined by immunohistochemical analysis. However, there was an elevation of MMP-2 expression in the disks of patients with displacement and without reduction (more severe alteration).

Limited fatty infiltration due to apoptosis in human degenerated temporomandibular joint disks: an immunohistochemical study.

In this study, we hypothesized that caspase 3, which plays a central role in the execution phase of cell apoptosis, could be involved in limiting fatty degeneration of the temporomandibular joint (TMJ) disks and therefore inhibit the TMJ disk tissue from completely degenerating into fatty tissue. Therefore, caspase 3 immunohistochemical expression in human TMJ degenerated disks was studied. Fifty-nine degenerated TMJ disks were stained with Harrys hematoxylin, and they were then examined with light microscopy to detect any pathologic changes typical of fatty degeneration. Sections from the same TMJ disk were immunostained also by a polyclonal anti-caspase 3 antibody. On morphologic observations, 11 disks of 59 degenerated ones also presented a fatty infiltration. Immunostaining with caspase 3 antibody was detected on adipocytes in the cytoplasm as well as the nuclei. Our results sustain the hypothesis that fatty degeneration is limited by apoptosis, being adipocytes immunolabeled by caspase 3 antibody. Hence, apart from the several factors that can trigger degeneration changes in TMJ disk, their appearance, spread, and permanence, at least for fatty degeneration, seem to be influenced by apoptosis.

Plasma rico em plaquetas de coelhos: introdução a um modelo animal experimental

.O conhecimento do fato de serem as plaquetas, com-provadamente, fonte de fatores de crescimento incentivou o estudo da acao de um concentrado de plaquetas no sen-tido de se aumentar o nivel de fatores de crescimento local, o que, teoricamente, melhoraria o processo cicatricial. Diversos autores passaram a propor a utilizacao do plasma rico em plaquetas (PRP), principalmente em as-sociacao com enxertos osseos

ADAMTS-4 and ADAMTS-5 expression in human temporomandibular joint discs with internal derangement, correlates with degeneration.

Temporomandibular joint (TMJ) internal derangement (ID) is one of the most common form of temporomandibular disorders. There is evidence showing the increased expression of matrix metalloproteinases (MMPs) in the cells from degenerated TMJ disc. ADAMTS are a large family of metalloproteases which are responsible for proteoglycans degradation. The present study aimed to evaluate ADAMTS-4 and ADAMTS-5 immunohistochemical expression in human TMJ discs from patients affected by ID, and to find out if there is any correlation with the degree of histopathological changes. Eighteen temporomandibular displaced disc specimens and sixteen TMJ disc control were used for the present study. Specimens were immunohistochemically processed and ADAMTS-4 and ADAMTS-5 expression were obtained respectively for the anterior (AB), intermediate (IB) and posterior (PB) bands and compared to the histopathological degeneration score (HDS). Immunoreactivity for ADAMTS-4 and -5, was observed in both not degenerated and degenerated human TMJ discs. Both the percentage of ADAMTS-4 and -5 immunostained cells (ES) and the intensity of staining (IS) were significantly greater in affected specimens compared with those in control discs. The ADAMTS-5 ES and IS of the 3 bands of the disc correlated to the TMJ disc HDS (0.001 < P < 0.05), on the other hand only AB and IB, ADAMTS-4 immunostaining scores correlated to HDS. According to these findings it can be assumed in that the more histopathological changes in the disc are detected, the higher levels of ADAMTS are produced. This in turn can lead to ECM breakdown and in turn to a more advanced disc displacement.

Histological and immunohistochemical evaluation of biphasic calcium phosphate and a mineral trioxide aggregate for bone healing in rat calvaria

This work focused on the process of bone repair of defects in standardized calvaria of Wistar rats treated with biphasic calcium phosphate (BCP), mineral trioxide aggregate (MTA), or a combination of the two. Eighty Wistar rats were divided into four treatment groups and were examined at 2 and 8 weeks. A surgical defect was created in the calvaria using a 6-mm diameter trephine drill. The cavity was treated with BCP, MTA, or BCP+MTA; untreated rats with clot formation served as controls. Samples were evaluated histologically and by immunohistochemical staining for areas of new osteoid tissue and new bone tissue, as well as the percentage of labelled cells using anti-bone morphogenetic protein receptor type 1B (anti-BMPR1B) antibodies. Statistically significant differences were found for all dependent variables (area of new osteoid tissue, area of new bone, and percentage immunostaining) by group (P<0.0001) and time (P<0.0001), and for the interaction of the two (P<0.0001). The MTA group at 8 weeks showed the highest amount of osteoid tissue. The same group also exhibited the highest amount of bone tissue formation. The 2-week MTA samples and 2-week BCP+MTA samples exhibited the highest percentages of stained cells. The best results in terms of the area of osteoid and bone tissue formation and the percentage of BMPR1B were observed for the MTA group, confirming that the combination of BCP+MTA does not result in a significant improvement.