Efeito do comprimento axial ocular na espessura da camada de fibras nervosas da retina e da camada de células ganglionares-plexiforme interna avaliadas por OCT espectral

Purpose: To evaluate the influence of ocular axial length on circumpapillary retinal nerve fiber layer and ganglion cell-inner plexiform layer thickness in healthy eyes after correcting for ocular magnification effect. Methods: In this cross-sectional study, we evaluated 120 eyes from 60 volunteer participants (myopes, emmetropes, and hyperopes). The thickness of the circumpapillary retinal nerve fiber layer and ganglion cell-inner plexiform layer were measured using the spectral optical coherence tomography (OCT)-Cirrus HD-OCT and correlated with ocular axial length. Adjustment for ocular magnification was performed by applying Littmann’s formula. Results: Before the adjustment for ocular magnification, age-adjusted mixed models analysis demonstrated a significant negative correlation between axial length and average circumpapillary retinal nerve fiber layer thickness (r=-0.43, p<0.001), inferior circumpapillary retinal nerve fiber layer thickness (r=-0.46, p<0.001), superior circumpapillary retinal nerve fiber layer thickness (r=-0.31, p<0.05), nasal circumpapillary retinal nerve fiber layer thickness (r=-0.35, p<0.001), and average ganglion cell-inner plexiform layer thickness (r=-0.35, p<0.05). However, after correcting for magnification effect, the results were considerably different, revealing only a positive correlation between axial length and temporal retinal nerve fiber layer thickness (r=0.42, p<0.001). . Additionally, we demonstrated a positive correlation between axial length and average ganglion cell-inner plexiform layer thickness (r=0.48, p<0.001). All other correlations were not found to be statistically significant. Conclusions: Before adjustment for ocular magnification, axial length was negatively correlated with circumpapillary retinal nerve fiber layer and ganglion cell-inner plexiform layer thickness measured by Cirrus-OCT. We attributed this effect to ocular magnification associated with greater axial lengths, which was corrected with the Littman’s formula. Further studies are required to investigate the impact of ocular magnification correction on the diagnostic accuracy of Cirrus-OCT.Objetivo: Avaliar a influência do comprimento axial ocular na espessura da camada de fibras nervosas da retina peripapilar e na espessura da camada de células ganglionares-plexiforme interna em olhos saudáveis após correção para efeito de magnificação ocular. Métodos: Neste estudo transversal, avaliamos 120 olhos de 60 participantes voluntários (míopes, emétropes e hipermétropes). A espessura da camada de fibras nervosas da retina peripapilar e da camada de células ganglionares-plexiforme interna foram medidas usando a tomografia de coerência óptica espectral (OCT)-Cirrus HD-OCT e correlacionada com o comprimento axial ocular. O ajuste para a magnificação ocular foi realizado aplicando a fórmula de Littmann. Resultados: Antes do ajuste para magnificação ocular, a análise de modelos mistos ajustada por idade demonstrou uma correlação negativa significante entre o comprimento axial e a espessura média da camada de fibras nervosas da retina peripapilar (r=-0,43; p<0,001), espessura da camada de fibras nervosas da retina peripapilar inferior (r=-0,46; p <0,001), espessura da camada de fibras nervosas da retina peripapilar superior (r=-0,31; p<0,05), espessura da camada de fibras nervosas da retina peripapilar nasal (r=-0,35; p<0,001) e espessura média das células ganglionares-plexiforme interna (r=-0,35; p<0,05). No entanto, após a correção do efeito de magnificação, os resultados foram consideravelmente diferentes, revelando apenas uma correlação positiva entre o comprimento axial e a espessura temporal da camada de fibras nervosas da retina (r=0,42; p<0,001). Além disso, demonstramos uma correlação positiva entre o comprimento axial e a espessura média das células ganglionares-plexiforme interna (r=0,48; p<0,001). Todas as outras correlações não foram consideradas estatisticamente significativas Conclusão: Antes do ajuste para o efeito de magnificação ocular, o comprimento axial estava negativamente correlacionado com a espessura da camada de fibras nervosas da retina peripapilar e das células ganglionares-plexiforme interna medido pelo Cirrus-OCT. Atribuimos esse efeito à magnificação ocular associada a comprimentos axiais maiores, o que foi corrigido com a fórmula de Littman. Mais estudos são necessários para investigar o impacto da correção da magnificação ocular na acurácia diagnóstica do Cirrus-OCT

A new approach for Y-TZP surface treatment: evaluations of roughness and bond strength to resin cemen

Objective: This study aims to evaluate the effect of sonochemical treatment on the surface of yttria-stabilized tetragonal zirconia (Y-TZP) before and after the final sintering. Material and Methods: Twenty-eight Y-TZP discs were divided into four groups (n=7), according to surface treatment: PRE: pre-sintering sonication with 30% nominal power for 15 min; POS: postsintering sonication with 30% nominal power for 15 min; JAT: air abrasion with 50-μm alumina particles; and CON: control group with no treatment. The POS and JAT groups were sintered before sonication and the PRE group after sonication. Surface roughness was analyzed using confocal microscopy, after which resin cement cylinders were placed on the surface of the Y-TZP discs and subjected to mechanical microshear bond strength test until fracture. Surface roughness and microshear bond strength values underwent ANOVA and the Tukey tests. Results: The surface roughness values for the PRE group (299.91 nm) and the POS group (291.23 nm) were not significantly different (p≥0.05), statistically, and the surface roughness value of the JAT group (925.21 nm) was higher than those of PRE and POS (p=0.007) groups. The mechanical microshear bond strength test showed that there was no statistically significant difference between the groups (p=0.08). Conclusions: Therefore, the results showed that sonochemical treatment modifies the Y-TZP surface and is similar to the well-established sandblasting surface treatment regarding the strength of the bond with the resin cement

A new approach for Y-TZP surface treatment: evaluations of roughness and bond strength to resin cemen

Objective: This study aims to evaluate the effect of sonochemical treatment on the surface of yttria-stabilized tetragonal zirconia (Y-TZP) before and after the final sintering. Material and Methods: Twenty-eight Y-TZP discs were divided into four groups (n=7), according to surface treatment: PRE: pre-sintering sonication with 30% nominal power for 15 min; POS: postsintering sonication with 30% nominal power for 15 min; JAT: air abrasion with 50-μm alumina particles; and CON: control group with no treatment. The POS and JAT groups were sintered before sonication and the PRE group after sonication. Surface roughness was analyzed using confocal microscopy, after which resin cement cylinders were placed on the surface of the Y-TZP discs and subjected to mechanical microshear bond strength test until fracture. Surface roughness and microshear bond strength values underwent ANOVA and the Tukey tests. Results: The surface roughness values for the PRE group (299.91 nm) and the POS group (291.23 nm) were not significantly different (p≥0.05), statistically, and the surface roughness value of the JAT group (925.21 nm) was higher than those of PRE and POS (p=0.007) groups. The mechanical microshear bond strength test showed that there was no statistically significant difference between the groups (p=0.08). Conclusions: Therefore, the results showed that sonochemical treatment modifies the Y-TZP surface and is similar to the well-established sandblasting surface treatment regarding the strength of the bond with the resin cement

Microtomographic, histomorphometric, and molecular features show a normal alveolar bone healing process in iNOS-deficient mice along a compensatory upregulation of eNOS and nNOS isoforms

Inducible nitric oxide synthase (iNOS) is one of the enzymes responsible for the synthesis of nitric oxide (NO), which is an important signaling molecule with effects on blood vessels, leukocytes, and bone cells. However, the role of iNOS in alveolar bone healing remains unclear. This study investigated the role of iNOS in alveolar bone healing after tooth extraction in mice. Methodology: C57Bl/6 wild type (WT) and iNOS genetically deficient (iNOS-KO) mice were subjected to upper incision tooth extraction, and alveolar bone healing was evaluated by micro-computed tomography (μCT) and histological/histomorphometric, birefringence, and molecular methods. Results: The expression of iNOS had very low control conditions, whereas a significant increase is observed in healing sites of WT mice, where iNOS mRNA levels peak at 7d time point, followed by a relative decrease at 14d and 21d. Regarding bone healing, both WT and iNOS-KO groups showed the usual phases characterized by the presence of clots, granulation tissue development along the inflammatory cell infiltration, angiogenesis, proliferation of fibroblasts and extracellular matrix synthesis, bone neoformation, and remodeling. The overall micro-computed tomography and histomorphometric and birefringence analyses showed similar bone healing readouts when WT and iNOS-KO strains are compared. Likewise, Real-Time PCR array analysis shows an overall similar gene expression pattern (including bone formation, bone resorption, and inflammatory and immunological markers) in healing sites of WT and iNOS-KO mice. Moreover, molecular analysis shows that nNOS and eNOS were significantly upregulated in the iNOS-KO group, suggesting that other NOS isoforms could compensate the absence of iNOS. Conclusion: The absence of iNOS does not result in a significant modulation of bone healing readouts in iNOS-KO mice. The upregulation of nNOS and eNOS may compensate iNOS absence, explaining the similar bone healing outcome in WT and iNOS-KO strains

HGMB1 and RAGE as Essential Components of Ti Osseointegration Process in Mice

The release of the prototypic DAMP High Mobility Group Box 1 (HMGB1) into extracellular environment and its binding to the Receptor for Advanced Glycation End Products (RAGE) has been described to trigger sterile inflammation and regulate healing outcome. However, their role on host response to Ti-based biomaterials and in the subsequent osseointegration remains unexplored. In this study, HMGB1 and RAGE inhibition in the Ti-mediated osseointegration were investigated in C57Bl/6 mice. C57Bl/6 mice received a Ti-device implantation (Ti-screw in the edentulous alveolar crest and a Ti-disc in the subcutaneous tissue) and were evaluated by microscopic (microCT [bone] and histology [bone and subcutaneous]) and molecular methods (ELISA, PCR array) during 3, 7, 14, and 21 days. Mice were divided into 4 groups: Control (no treatment); GZA (IP injection of Glycyrrhizic Acid for HMGB1 inhibition, 4 mg/Kg/day); RAP (IP injection of RAGE Antagonistic Peptide, 4 mg/Kg/day), and vehicle controls (1.5% DMSO solution for GZA and 0.9% saline solution for RAP); treatments were given at all experimental time points, starting 1 day before surgeries. HMGB1 was detected in the Ti-implantation sites, adsorbed to the screws/discs. In Control and vehicle groups, osseointegration was characterized by a slight inflammatory response at early time points, followed by a gradual bone apposition and matrix maturation at late time points. The inhibition of HMGB1 or RAGE impaired the osseointegration, affecting the dynamics of mineralized and organic bone matrix, and resulting in a foreign body reaction, with persistence of macrophages, necrotic bone, and foreign body giant cells until later time points. While Control samples were characterized by a balance between M1 and M2-type response in bone and subcutaneous sites of implantation, and also MSC markers, the inhibition of HMGB1 or RAGE caused a higher expression M1 markers and pro-inflammatory cytokines, as well chemokines and receptors for macrophage migration until later time points. In conclusion, HMGB1 and RAGE have a marked role in the osseointegration, evidenced by their influence on host inflammatory immune response, which includes macrophages migration and M1/M2 response, MSC markers expression, which collectively modulate bone matrix deposition and osseointegration outcome

Papel das células Th17 e T reguladoras (TREGs) na imunomodulação de lesões periapicais experimentais

The pathogenesis of periapical lesions is determined by the balance between host proinflammatory immune response and counteracting anti-inflammatory and reparative responses. In this context, different subtypes of lymphocytes and their products have been implicated in periapical lesion pathogenesis, such as regulatory T cells (Tregs) and Th17. While Tregs has been demonstrated as potential immunoregulatory agents, Th17 has been correlated with greater severity of disease. In this study, we investigated (in a cause-and-effect manner) the involvement of Tregs and Th17, besides the impact of different therapies in the progression of experimental periapical lesions. With this aim, periapical lesions were induced (pulp exposure and bacterial inoculation) in C57Bl/6 (wild-type), IL-17KO and CCR4KO mice and treated with antiglucocorticoid-induced TNF receptor family regulated gene (anti-GITR) to inhibit Treg function or alternatively with CCL22-releasing, poly lactic-glycolic acid particles to induce site-specific migration of Tregs. Furthermore, WT mice were treated with anti-RANKL using continuous or intermittent protocols, and with anti-TNF therapy as a control. After treatment, lesions were analyzed for Treg or Th17 influx and phenotype, overall periapical bone loss, and inflammatory/immunologic and wound healing marker expression (RealTimePCRarray, ELISA). Treg inhibition by anti-GITR or CCR4 depletion results in a significant increase in periapical lesion severity, associated with upregulation of proinflammatory, Th1, Th17, and tissue destruction markers in parallel with decreased Treg and healing marker expression. The local release of CCL22 in the root canal system resulted in the promotion of Treg migration in a CCR4-dependent manner, leading to the arrest of periapical lesion progression, associated with down regulation of proinflammatory and tissue destruction markers in parallel with increased Treg and healing marker expression. Anti-RANKL treatment arrested lesion development, but prompted a continuous inflammatory response characterized by unremitting elevated expression of proinflammatory cytokines and tissue destructive mediators, and decreased expression of Tregs and wound healing markers levels. This treatment triggered lesion development relapse and was associated with high TCD4 effector/suppressor cells ratio and active lesions gene expression signature. Anti-TNF treatment limits lesions progression and does not drives lesions relapse upon cessation, being associated with attenuated host response. Finally, the absence of IL-17 results in a significant decrease in periapical lesions severity, associated with upregulation of healing markers and antiinflammatory cytokines, in parallel with decreased expression of tissue destruction markers and proinflammatory cytokines. Indeed, histomorphometric analysis showed lower concentration of osteoclasts, neutrophils and mononuclear cells in periapical lesions without IL-17. Therefore, we concluded that regulatory T cells are essential in the control of apical periodontitis, while Th17 cells accentuate the lesions severity. Compared with other clinical strategies, such as anti-RANKL therapy, which perpetuates the host inflammatory response prompting lesion relapse, chemoattraction of Treg as well as inhibition of Th17 may be promising strategies for the clinical management of periapical lesions.A patogênese das lesões periapicais é determinada pelo equilíbrio entre a resposta imune pró-inflamatória do hospedeiro e a resposta anti-inflamatória/reparo. Diferentes subtipos de linfócitos e seus produtos têm sido implicados na patogênese dessas lesões, tais como as células T reguladoras (Tregs) e Th17. Enquanto as Tregs parecem ser potenciais agentes imuno-reguladores, Th17 parece estar associada à maior severidade da doença. Neste estudo, foram investigados o envolvimento de Tregs e Th17, além do impacto de diferentes terapias na progressão de lesões periapicais experimentais. Para isso, lesões periapicais foram induzidas (exposição pulpar e inoculação bacteriana) em camundongos C57BL/6, IL- 17KO e CCR4KO tratados com anticorpos anti-GITR (inibe a função de Treg) ou com CCL22p, partículas de ácido poliláctico-glicólico (induz a migração de Tregs). Além disso, os camundongos WT foram tratados com anti-RANKL utilizando protocolos contínuos ou intermitentes, ou com anti-TNF como controle. Posteriormente, analisou-se o fluxo e fenótipo de Tregs e Th17, perda óssea periapical e expressão de citocinas inflamatórias/imunológicas e marcadores de reparo (RealTimePCRarray, ELISA). A inibição de Tregs (depleção de CCR4 ou terapia anti-GITR), aumentou significantemente a severidade da lesão, associada com o aumento da expressão de citocinas pró-inflamatórias, Th1, Th17 e mediadores de destruição tecidual em paralelo com a diminuição dos marcadores de Treg e de reparo. A liberação local de CCL22 no canal radicular resultou na migração de Treg, dependente de CCR4, levando à modulação da lesão periapical, associada com a diminuição da expressão de marcadores pró-inflamatórios e de destruição tecidual em paralelo com o aumento dos marcadores de Tregs e de reparo. O tratamento anti-RANKL impediu o desenvolvimento da lesão, mas provocou uma resposta inflamatória contínua caracterizada pela elevada expressão de citocinas pró-inflamatórias e mediadores de destruição tecidual e diminuição da expressão dos marcadores de Tregs e de reparo. Este tratamento levou à recidiva da lesão e foi associado com o aumento da razão células TCD4 efetoras/supressoras e com o perfil de expressão gênica de lesões ativas. O tratamento anti-TNF limitou a progressão das lesões e não promoveu sua recidiva após o término da terapia, estando associado à resposta do hospedeiro atenuada. Por fim, a ausência de IL-17 resultou em lesões menos severas, associadas com o aumento da expressão de marcadores de reparo e citocinas anti-inflamatórias, em paralelo com a menor expressão de marcadores de destruição tecidual e citocinas pró-inflamatórias. De fato, observou-se menor concentração de osteoclastos, neutrófilos e células inflamatórias, na ausência de IL-17. Conclui-se, portanto, que as células T reguladoras são essenciais no controle da lesão periapical, enquanto as células Th17 acentuam a severidade dessas lesões. Comparando com outras estratégias clínicas, tais como a terapia anti-RANKL que perpetua a resposta inflamatória do hospedeiro levando a recidiva da lesão, a quimioatração de Treg bem como a inibição de Th17 podem ser estratégias promissoras para o manejo clínico das lesões periapicais

Morphometric and molecular characterization of the role of iNOS in alveolar bone repair process in homeostatic and infectious conditions

A óxido nítrico sintase induzível (iNOS) é uma enzima responsável pela síntese do óxido nítrico, envolvido na regulação de vários processos fisiológicos, com destaque para relevantes efeitos sobre o tecido ósseo. Entretanto, o papel da iNOS no reparo ósseo alveolar permanece pouco conhecido. Assim, o objetivo deste estudo foi caracterizar o papel da iNOS no processo de reparo ósseo alveolar pósexodontia em condições homeostáticas (controle) e infecciosas em camundongos. Para isso, foram utilizados animais das linhagens WT (C57Bl/6) e iNOSKO, divididos em 2 grupos, condição homeostática (exodontia do incisivo superior direito) e alveolite experimental (induzida pela inoculação de uma suspensão de cultura bacteriana), e analisados de acordo com os diferentes períodos experimentais (0, 7, 14 e 21 dias pós-exodontia), através da análise histomorfométrica e molecular. Na análise histomorfométrica, avaliou-se a densidade de volume das estruturas referentes ao coágulo sanguíneo, tecido conjuntivo e tecido ósseo. Na análise molecular, quantificou-se a expressão de mRNA codificando genes de marcadores do metabolismo ósseo; marcadores de osteoclastos; citocinas e quimiocinas, através de reações de RealTimePCR. A expressão de iNOS esteve presente durante todo o processo de reparo ósseo alveolar nos camundongos C57Bl/6, porém de maneira mais expressiva no período de 7 dias pós-exodontia, e se mostrou aumentada pela indução de alveolite. A análise histomorfométrica demonstrou discretas alterações no processo de reparo ósseo alveolar, na ausência de iNOS, tanto em condições homeostáticas quanto infecciosas. Em condições homeostáticas, a ausência de iNOS não impactou de forma significativa o processo de reparo ósseo alveolar pósexodontia, mas se mostrou associada à modulação de vasos sanguíneos. Já em condições infecciosas, a ausência de iNOS se mostrou associada à modulação de células inflamatórias, osteoblastos e osteoclastos. De forma geral, conclui-se que embora a enzima iNOS module certos aspectos do processo de reparo ósseo alveolar de forma pontual, sua ausência não interferiu de forma significativa nesse processo.The inducible nitric oxide synthase (iNOS) is an enzyme responsible for the synthesis of nitric oxide, a reactive molecule involved in the regulation of several physiological processes, highlighting relevant effects on bone tissue. However, the role of iNOS in alveolar bone repair remains unknown. The aim of this study was to characterize the role of iNOS in alveolar bone healing process after dental extraction in homeostatic and infectious conditions in mice. With this aim, WT (C57Bl/6) and iNOSKO mice strains were divided into 2 groups, homeostatic condition (extraction of the upper right incisor) and experimental alveolitis (induced by inoculation of a suspension of bacterial culture), and analyzed according to the different experimental periods (0, 7, 14 and 21 days post-extraction), through molecular and histomorphometric analysis. In histomorphometric analysis, the volume density of structures related to blood clot, tissue and bone were evaluated. The molecular analysis quantified the expression of mRNA encoding genes of defined as bone metabolism markers; osteoclast markers, as well cytokines and chemokines through RealTimePCR reactions. The expression of iNOS was detected during the all process of the alveolar bone repair in C57Bl/6 mice, with an expression peak at 7 days post-extraction time point, and was significantly enhanced by alveolitis induction. Histomorphometric analysis showed small changes in alveolar bone repair process in the absence of iNOS, in both homeostatic as infectious conditions. Under homeostatic conditions, the absence of iNOS did not impact significantly the process of alveolar bone healing after dental extraction, but it was associated with modulation of blood vessels formation. In the infectious conditions scenario, the absence of iNOS was associated with modulation of inflammatory cells, osteoblasts and osteoclasts counts. In general, it is concluded that even the enzyme iNOS module some aspects of alveolar bone repair in a particular and punctual manner, their absence does not interfere significantly in the overall outcome of alveolar bone repair process

Self-induced lens subluxation with avulsion of ciliary processes in Tourette Syndrome

Purpose: To report a case of self-induced eye injury resulting in lens subluxation combined with avulsion of ciliary processes in a patient with Tourette Syndrome. Observation: A 14-year-old male had repeated involuntary trauma to the left side of his face. On exam, left eye lens subluxation combined with ciliary process avulsion were noted. Pars plana vitrectomy and lensectomy were performed. Conclusions and Importance: This report of self-inflicted ciliary processes detachment in Tourette Syndrome is the first of its kind. Ocular injuries reported in the literature include isolated cases of lens luxation, retinal detachment and orbital hemorrhage. Additionally, iatrogenic conjunctival laceration and corneal abrasion have been reported due to involuntary movements during clinical examination. This case provides further evidence that patients with Tourette Syndrome may be at risk of eye injury due to the involuntary jerk movements associated with this condition. Patients with involuntary tics that put their eyes at risk should be advised to wear safety eye wear to avoid eye trauma and its deleterious visual consequences. Keywords: Tourette syndrome, Ocular trauma, Ciliary processes traum