Improved vascularisation but inefficient in vivo bone regeneration of adipose stem cells and poly-3-hydroxybutyrate-co-3-hydroxyvalerate scaffolds in xeno-free conditions.

Bone defects are a common clinical situation. However, bone regeneration remains a challenge and faces the limitation of poor engraftment due to deficient vascularisation. Poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHB-HV) and human adipose stem cells (hASC) are promising for vascularisation and bone regeneration. Therefore, we sought to investigate the bone regenerative capacity of hASCs cultured in allogeneic human serum (aHS) and PHB-HV scaffolds in a nude mouse model of the critical-sized calvarial defect. We evaluated bone healing for three treatment groups: empty (control), PHB-HV and PHB-HV + hASCs. The pre-implant analysis showed that hASCs colonised the PHB-HV scaffolds maintaining cell viability before implantation. Histological analysis revealed that PHB-HV scaffolds were tolerated in vivo; they integrated with adjacent tissue eliciting a response like a foreign body reaction, and tiny primary bone was observed only in the PHB-HV group. Also, the µ-CT analysis revealed only approximately 10% of new bone in the bone defect area in both the PHB-HV and PHB-HV + hASCs groups. The expression of BGLAP and its protein (osteocalcin) by PHB-HV + hASCs group and native bone was similar while the other bone markers RUNX2, ALPL and COL1A1 were upregulated, but this expression remained significantly lower compared to the native bone. Nevertheless, the PHB-HV group showed neovascularisation at 12 weeks post-implantation while PHB-HV + hASCs group also exhibited higher VEGFA expression as well as a higher number of vessels at 4 weeks post-implantation, and, consequently, earlier neovascularisation. This neovascularisation must be due to scaffold architecture, improved by hASCs, that survived for the long term in vivo in the PHB-HV + hASCs group. These results demonstrated that hASCs cultured in aHS combined with PHB-HV scaffolds were ineffective to promote bone regeneration, although the construct of hASCs + PHB-HV in xeno-free conditions improved scaffold vascularisation representing a strategy potentially promising for other tissue engineering applications.

Polyhydroxybutyrate-co-hydroxyvalerate structures loaded with adipose stem cells promote skin healing with reduced scarring.

Currently available skin substitutes are still associated with a range of problems including poor engraftment resulting from deficient vascularization, and excessive scar formation, among others. Trying to overcome these issues, this work proposes the combination of poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) structures with adipose-derived stem cells (ASCs) to offer biomechanical and biochemical signaling cues necessary to improve wound healing in a full-thickness model. PHBV scaffold maintained the wound moisture and demonstrated enough mechanical properties to withstand wound contraction. Also, exudate and inflammatory cell infiltration enhanced the degradation of the structure, and thus healing progression. After 28 days all the wounds were closed and the PHBV scaffold was completely degraded. The transplanted ASCs were detected in the wound area only at day 7, correlating with an up-regulation of VEGF and bFGF at this time point that consequently led to a significant higher vessel density in the group that received the PHBV loaded with ASCs. Subsequently, the dermis formed in the presence of the PHBV loaded with ASCs possesses a more complex collagen structure. Additionally, an anti-scarring effect was observed in the presence of the PHBV scaffold indicated by a down-regulation of TGF-ß1 and α-SMA together with an increase of TGF-ß3, when associated with ASCs. These results indicate that although PHBV scaffold was able to guide the wound healing process with reduced scarring, the presence of ASCs was crucial to enhance vascularization and provide a better quality neo-skin. Therefore, we can conclude that PHBV loaded with ASCs possesses the necessary bioactive cues to improve wound healing with reduced scarring.

Poly(hydroxybutyrate-co-hydroxyvalerate) bilayer skin tissue engineering constructs with improved epidermal rearrangement.

Bilayer skin substitutes constitute an attractive strategy towards improved skin wound healing. Therefore, solvent casting and freeze-drying methodologies are used to produce polyhydroxybutyrate-co-hydroxyvalerate (PHBV) thin nanoporous membranes and 3D porous scaffolds that are combined in bilayer structures to recreate the epidermal and dermal layers, respectively. The combination of these methodologies allow attaining a bilayer structure with a high water retention capability and adequate mechanical properties, susceptible to enzymes degradative action. Cultures established with human keratinocytes (hKC) and dermal fibroblasts (hDFb) confirm the suitability of the PHBV structures to support cell adhesion and proliferation. Nonetheless, when co-cultured under defined conditions, hKC are able to grow and rearrange in a multilayer structure with proliferative cells in the basal layer, and cells expressing a terminal differentiation marker in the upper layer. Therefore, PHBV bilayer structures demonstrate properties that favor skin cells performance, thus representing a promising strategy to improve wound healing.

Human serum is a suitable supplement for the osteogenic differentiation of human adipose-derived stem cells seeded on poly-3-hydroxibutyrate-co-3-hydroxyvalerate scaffolds.

Human adipose-derived stem cells (hASCs) are currently a point of focus for bone tissue engineering applications. However, the ex vivo expansion of stem cells before clinical application remains a challenge. Fetal bovine serum (FBS) is largely used as a medium supplement and exposes the recipient to infections and immunological reactions. In this study, we evaluated the osteogenic differentiation process of hASCs in poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHB-HV) scaffolds with the osteogenic medium supplemented with pooled allogeneic human serum (aHS). The hASCs grown in the presence of FBS or aHS did not show remarkable differences in morphology or immunophenotype. The PHB-HV scaffolds, which were developed by the freeze-drying technique, showed an adequate porous structure and mechanical performance as observed by micro-computed tomography, scanning electron microscopy (SEM), and compression test. The three-dimensional structure was suitable for allowing cell colonization, which was revealed by SEM micrographs. Moreover, these scaffolds were not toxic to cells as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The differentiation capacity of hASCs seeded on scaffolds was confirmed by the reduction of the proliferation, the alkaline phosphatase (AP) activity, expression of osteogenic gene markers (AP, collagen type I, Runx2, and osteocalcin), and the expression of bone markers, such as osteopontin, osteocalcin, and collagen type I. The osteogenic capacity of hASCs seeded on PHB-HV scaffolds indicates that this scaffold is adequate for cell growth and differentiation and that aHS is a promising supplement for the in vitro expansion of hASCs. In conclusion, this strategy seems to be useful and safe for application in bone tissue engineering.

Endothelial differentiation of human stem cells seeded onto electrospun polyhydroxybutyrate/polyhydroxybutyrate-co-hydroxyvalerate fiber mesh.

Tissue engineering is based on the association of cultured cells with structural matrices and the incorporation of signaling molecules for inducing tissue regeneration. Despite its enormous potential, tissue engineering faces a major challenge concerning the maintenance of cell viability after the implantation of the constructs. The lack of a functional vasculature within the implant compromises the delivery of nutrients to and removal of metabolites from the cells, which can lead to implant failure. In this sense, our investigation aims to develop a new strategy for enhancing vascularization in tissue engineering constructs. This study's aim was to establish a culture of human adipose tissue-derived stem cells (hASCs) to evaluate the biocompatibility of electrospun fiber mesh made of polyhydroxybutyrate (PHB) and its copolymer poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHB-HV) and to promote the differentiation of hASCs into the endothelial lineage. Fiber mesh was produced by blending 30% PHB with 70% PHB-HV and its physical characterization was conducted using scanning electron microscopy analysis (SEM). Using electrospinning, fiber mesh was obtained with diameters ranging 300 nm to 1.3 µm. To assess the biological performance, hASCs were extracted, cultured, characterized by flow cytometry, expanded and seeded onto electrospun PHB/PHB-HV fiber mesh. Various aspects of the cells were analyzed in vitro using SEM, MTT assay and Calcein-AM staining. The in vitro evaluation demonstrated good adhesion and a normal morphology of the hASCs. After 7, 14 and 21 days of seeding hASCs onto electrospun PHB/PHB-HV fiber mesh, the cells remained viable and proliferative. Moreover, when cultured with endothelial differentiation medium (i.e., medium containing VEGF and bFGF), the hASCs expressed endothelial markers such as VE-Cadherin and the vWF factor. Therefore, the electrospun PHB/PHB-HV fiber mesh appears to be a suitable material that can be used in combination with endothelial-differentiated cells to improve vascularization in engineered bone tissues.

Prevenção e controle das seqüelas bucais em pacientes irradiados por tumores de cabeça e pescoço / Prevention and control of sequels in the mouth of patients treated with radiation therapy for head and neck tumors

A cirurgia e a radioterapia são os principais métodos de tratamento das neoplasias de cabeça e pescoço. Dentre os efeitos colaterais resultantes da interação da radiação ionizante sobre os tecidos, temos dermatite, mucosite, xerostomia, candidíase, alteração do paladar, disfagia, cárie, trismo e osteorradionecrose. OBJETIVO: Avaliar a condição odontológica dos pacientes, através de protocolo que permita impedir ou minimizar os efeitos da radiação sobre os tecidos da cavidade bucal. MATERIAIS E MÉTODOS: Realizou-se acompanhamento odontológico, antes, durante e até 180 dias após a radioterapia, em 12 pacientes submetidos a cirurgia e radioterapia, ou radioterapia exclusiva. RESULTADOS: Efeitos como dermatite, mucosite, alteração do paladar e disfagia cresceram em proporção a partir da segunda semana de tratamento até o final das aplicações, decrescendo visivelmente quando do término, chegando próximos aos valores basais após 180 dias. Quanto à xerostomia, a redução ocorreu mais lentamente e com menor efetividade. Cárie, trismo e osteorradionecrose não foram observados durante o período de avaliação. CONCLUSAO: O acompanhamento odontológico sistemático, junto com medidas preventivas como adequação bucal prévia, orientações sobre higienização, utilização de bochechos de água bicarbonatada, chá de camomila, aplicação tópica de flúor, contribuíram para promover melhores condições de restabelecimento em pacientes com neoplasia da região de cabeça e pescoço submetidos à radioterapia.

Avaliação do espaço aéreo faríngeo em pacientes com retrognatismo mandibular tratados com aparelho Herbst / Evaluation of pharyngeal airway in patients with manidular retrognatism treated with Herbst apliance

O objetivo desse trabalho foi avaliar radiograficamente a mudança do espaço decorrente do uso do aparelho ortopédico de Herbst em adolescentes com retrognatismo mandibular. A amostra constou das telerradiografias em norma lateral referente a 22 pacientes (Idade média de 12 anos e 10 meses, Desvio padrão + - 0,94) e analisadas as diferenças do espaço aéreo posterior (EAP) e distância do osso hióide ao plano mandibular (H-Pm) nos tempos: inicial (T1), seis meses(T2)e um ano (T3) de tratamento com aparelho de Herbst. Os resultados mostraram que a grandeza cefalométrica EAP foi maior nos tempos T2 e T3, quando comparado ao tempo T1 (p< 0,001). A grandeza cefalométrica da distância do osso hióide ao plano mandibular (H-Pm) não mostrou diferença de valores nos diferentes tempos (p=0,985). Com base nos resultados podemos concluir, que embora não houvesse diferença na medida H-Pm o uso do aparelho de Herbest foi eficiente no aumento do espaço aéreo faríngeo posterior em pacientes com retrognatismo mandibular.

Ain of this study was to report radiographic change in pharyngeal upper airway with Herbst mandibular advancement device in adolescents with mandibular retrognastism. The sample was composed of cephalometric roentgenograms obtained in 22 patients (Mean age 12.89 +- 0.94 years) and evaluated the differences of posterior airway space (PAS) and hyoid bone to mandibular plane distance in times: preoperative (T1), six months (T2) and one year (T3) of treatment with Herbst appliance. Results showed that cephalometric measurements of the distance between the hyoid bone and the mandible (MP-H) don’t increase in different times (p=0,985). In these results our conclusion is that. Herbst appliance was efficient in increased pharyngeal upper airway in patients with mandibular retrognatism.

Avaliaçäo da variaçäo da pressäo arterial em pacientes especiais devida à administração de anestésico local sem vasoconstritor / Avaliation above the arterial pression variation among special patients according to the anesthesic loco administration without constrictor vases

Os autores realizaram a avaliaçäo de variaçäo da pressäo arterial em 53 pacientes, em tratamento na Disciplina de Odontologia para Pacientes Especiais, após a aplicaçäo de anestesia local à base de hidroclorido de mepivacaína 3 por cento sem vasoconstritor "Safety - Plus" (Septodont). Os resultados revelaram alteraçöes na pressäo diastólica, com discreta queda

Jones jig e barra transpalatina: tratamento alternativo na correçäo unilateral da má oclusäo Classe II, divisäo 2, subdivisäo / Jones jig and the palatal bar: alternative treatment in the unilateral correction of malocclusion Class II, division 2, subdivision

Este trabalho tem como objetivo avaliar clínica e cefalometricamente, um tratamento realizado com a utilizaçäo do aparelho "Jones jig" associado à barra transpalatina, para correçäo da assimetria dentária com desvio da linha mediana, de um paciente portador de má oclusäo Classe II, divisäo 2, subdivisäo. Foi demonstrada a distalizaçäo dos molares superiores num período curto de tempo, com um mínimo de perda de ancoragem e sem a necessidade de colaboraçäo do paciente. Após a correçäo Classe II, foi realizada a montagem de aparelhagem fixa superior e inferior para finalizaçäo do tratamento