Efficacy and safety of a new heterologous fibrin biopolymer on socket bone healing after tooth extraction: An experimental pre-clinical study.

AIM: To assess the efficacy of heterologous fibrin biopolymer (HFB) in promoting alveolar bone healing after tooth extraction in rats. MATERIALS AND METHODS: The upper right incisors of 48 Wistar rats were extracted. Toothless sockets were filled with HFB (HFBG, n = 24) or blood clot (BCG, n = 24). The tooth extraction sites were subjected to micro-computed tomography (micro-CT), histological, histomorphometric and immunohistochemical (for Runt-related transcription factor 2/Runx2 and tartrate-resistant acid phosphatase/TRAP) analyses on days 0, 7, 14 and 42 after extraction. RESULTS: Socket volume remained similar between days 0 and 14 (69 ± 5.4 mm3), except in the BCG on day 14, when it was 10% lower (p = .043). Although the number of Runx2+ osteoblasts was high and similar in both groups (34 × 102 cells/mm2), the HFBG showed lower inflammatory process and osteoclast activity than BCG at 7 days. On day 14, the number of Runx2+ osteoblasts remained high and similar to the previous period in both groups. However, osteoclast activity increased. This increase was 55% lower in the HFBG than BCG. In the BCG, the presence of an inflammatory process and larger and numerous osteoclasts on day 14 led to resorption of the alveolar bone ridge and newly formed bone. On day 42, numbers of Runx2+ osteoblast and TRAP+ osteoclasts decreased dramatically in both groups. Although the BCG exhibited a more mature cortical bone formation, it exhibited a higher socket reduction (28.3 ± 6.67%) and smaller bone volume (37 ± 5.8 mm3) compared with HFBG (socket reduction of 14.8 ± 7.14% and total bone volume of 46 ± 5.4 mm3). CONCLUSIONS: HFB effectively suppresses osteoclast activity and reduces alveolar bone resorption compared with blood clot, thus preventing three-dimensional bone loss, particularly during the early healing period. HFB emerges as a promising biopharmaceutical material for enhancing healing processes after tooth extraction.

Effects of glass-ceramic produced by the sol-gel route in macrophages recruitment and polarization into bone tissue regeneration.

Effective bone substitute biomaterials remain an important challenge in patients with large bone defects. Glass ceramics produced by different synthesis routes may result in changes in the material physicochemical properties and consequently affect the success or failure of the bone healing response. To investigate the differences in the orchestration of the inflammatory and healing process in bone grafting and repair using different glass-ceramic routes production. Thirty male Wistar rats underwent surgical unilateral parietal defects filled with silicate glass-ceramic produced by distinct routes: BS - particulate glass-ceramic produced via the fusion/solidification route, and BG - particulate glass-ceramic produced via the sol-gel route. After 7, 14, and 21 days from biomaterial grafting, parietal bones were removed to be analyzed under H&E and Massons' Trichome staining, and immunohistochemistry for CD206, iNOS, and TGF-ß. Our findings demonstrated that the density of lymphocytes and plasma cells was significantly higher in the BS group at 45, and 7 days compared to the BG group, respectively. Furthermore, a significant increase of foreign body giant cells (FBGCs) in the BG group at day 7, compared to BS was found, demonstrating early efficient recruitment of FBGCs against sol-gel-derived glass-ceramic particulate (BS group). According to macrophage profiles, CD206+ macrophages enhanced at the final periods of both groups, being significantly higher at 45 days of BS compared to the BG group. On the other hand, the density of transformation growth factor beta (TGF-ß) positive cells on 21 days were the highest in BG, and the lowest in the BS group, demonstrating a differential synergy among groups. Noteworthy, TGF-ß+ cells were significantly higher at 21 days of BG compared to the BS group. Glass-ceramic biomaterials can act differently in the biological process of bone remodeling due to their route production, being the sol-gel route more efficient to activate M2 macrophages and specific FBGCs compared to the traditional route. Altogether, these features lead to a better understanding of the effectiveness of inflammatory response for biomaterial degradation and provide new insights for further preclinical and clinical studies involved in bone healing.

ALDH1 and CD44 immunoexpression as prognostic indicators of invasion and metastasis in oral squamous cell carcinoma / Immunoexpressão de ALDH1 e CD44 como indicador de prognóstico de invasão e metástase em carcinoma epidermoide de boca

Oral squamous cell carcinoma (OSCC) is one of the most common cancer in the head and neck and results in high morbidity and mortality annually, being the worst prognosis related to the presence of metastasis in cervical lymph nodes. Metastasis has been associated with a subpopulation of tumor cells, called cancer stem cells (CSCs), which consists of a small population with stem-like cells properties, higher rate of migration and metastatic potential compared to other ordinary tumor cells from the tumor bulk. The aim of present study was to evaluate the immunoexpression of the CSC markers ALDH1 and CD44 in primary sites of OSCC and corresponding metastatic lymph nodes, by means of immunohistochemistry. The immunolabeling was further correlated with clinicopathological data. Archived Formalin-fixed, Paraffin-embedded tumor tissue specimens (n=50) and corresponding metastatic lymph nodes (n=25) were obtained from 50 patients with OSCC after surgical treatment. CD44 and ALDH1 immunostaining were semi-quantitatively scored according to the proportion and intensity of positive cells within the invasive front and metastatic cervical lymph nodes as a whole. The percentage of ALDH1 and CD44 positive tumor cells as well as immunostaining intensity was graded and a combined score, ranging from 0 to 9 (ALDH1) or 0 to 12 (CD44), was obtained by multiplying both parameters. Next, combined scores were dichotomized into a final score classified as low (ALDH1≤ 2; CD44≤ 4) or high (ALDH1> 2; CD44> 4) immunoexpression. ALDH1 and CD44 immunoexpression was detected in both primary and metastatic tumor sites, although with different immunolabeling pattern. ALDH1-positive tumor cells consisted of scattered patches and no immunoexpression was observed within keratin pearls. Conversely, CD44 immunopositivity was more homogeneous and widely distributed, with higher labeling in peripheral areas of the tumor islands within the tumor invasion front. Although not statistically significant, the means of ALDH1high (p= 0.0985) and CD44high (p= 0.1632; Mann- Whitney post-test) immunoexpression were higher in metastatic lymph nodes compared to primary tumors. ALDH1high was positively associated (p= 0.0184) with perivascular invasion, while CD44high was positively associated (p= 0.0186; Fisher's Exact Test) with metastasis (N+). Five-year survival rates tended to be lower in patients with ALDH1high immunoexpression compared to ALDH1low, although with no statistical significance (p= 0.1303). In summary, the present study revealed that CD44 is highly labeled in tumor cell from metastatic sites, being associated with lymph node metastasis, while ALDH1 high immunostaining was associated with perivascular invasion. Altogether, it suggests that immunoexpression of CD44 and ALDH1 links the cancer stem cell phenotype with OSCC invasion and metastasis.(AU)

O carcinoma epidermóide de boca (CEB) é uma das neoplasias mais comuns da região de cabeça e pescoço e resulta em alta morbidade e mortalidade anualmente, estando o pior prognóstico relacionado à presença de metástase em linfonodos cervicais. O processo de metástase tem sido associado a uma subpopulação de células tumorais, chamadas células-tronco de câncer (CSC, do inglês Cancer stem cells), que consistem em uma pequena população de células com propriedades de células-tronco, incluindo maior taxa de migração e potencial metastático em comparação com outras células tumorais. O objetivo do presente estudo foi avaliar os marcadores candidatos de CSCs ALDH1 e CD44 em tumores primários de CEB e metástases linfonodais correspondentes, por meio de imuno-histoquímica. A imunomarcação foi posteriormente correlacionada com dados clínico-patológicos. Foram obtidas amostras de tecido tumoral parafinado fixado em formalina (n = 50) e os linfonodos metastáticos correspondentes (n = 25) de 50 pacientes com CEB submetidos somente ao tratamento cirúrgico. Os marcadores CD44 e ALDH1 foram analisados de forma semi-quantitativa de acordo com a proporção e intensidade de células positivas no fronte de invasão e em linfonodos cervicais metastáticos como um todo. A porcentagem de células tumorais ALDH1 e CD44 positivas, bem como a intensidade da imunomarcação, foi classificada em um escore combinado obtido pela multiplicação de ambos os parâmetros, variando de 0 a 9 (ALDH1) ou 0 a 12 (CD44). Em seguida, as pontuações combinadas foram dicotomizadas em um escore final classificado como baixo (do inglês low) (ALDH1 ≤ 2; CD44 ≤ 4) ou alto (do inglês high) (ALDH1> 2; CD44> 4). A imunoexpressão de ALDH1 e CD44 foi detectada tanto em tumores primários quanto em linfonodos cervicais metastáticos, embora com padrão diferente de imunomarcação. Células tumorais ALDH1-positivas foram identificadas como focais e dispersas ao longo do fronte de invasão, sem imunomarcação nas pérolas córneas. Em contraste, a imunopositividade para CD44 foi mais homogênea e amplamente distribuída, com maior imunomarcação em áreas periféricas das ilhotas tumorais presentes no fronte de invasão. Embora não estatisticamente significativa, as médias da imunoexpressão ALDH1high (p = 0.0985) e CD44high (p = 0.1632, pós-teste de Mann-Whitney) foram maiores em linfonodos metastáticos em comparação com tumores primários. ALDH1high foi positivamente associado com invasão perivascular (p = 0.0184), enquanto CD44high foi com metástase (N+) (p = 0.0186; teste exato de Fisher). As taxas de sobrevida global em 5 anos tenderam a ser mais baixas em pacientes com imunoexpressão elevada de ALDH1 em comparação com ALDH1low, embora sem significância estatística (p = 0.1303). Em resumo, o presente estudo revelou que a elevada imunomarcação de CD44 está significativamente associada com metástases linfonodais, enquanto que a elevada imunomarcação de ALDH1 está associada com invasão perivascular. Em conjunto, sugerimos que a imunoexpressão de CD44 e ALDH1 esteja relacionada com o fenótipo de células tronco de câncer que tem capacidade de invasão e metástase em CEB.(AU)