Novel PHB/PCL scaffolds produced by melt base technologies

[Excerpt] On this work, the natural origin polymer Polyhydroxybutyrate (PHB) was melt blended with synthetic aliphatic polyester Polye-caprolactone (PCL). The ratio of PHB/PCL was varied from 25% to 75% by weight. These blends were further injection moulded and characterized. The thermal properties of the developed blends were accessed by differential scanning calorimetry DSC). The effect of the ratio PHB/PCL on the mechanical properties (tensile modulus and tensile strength) was determined by tensile tests. […]info:eu-repo/semantics/publishedVersio

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

Prevention and control of sequels in the mouth of patients treated with radiation therapy for head and neck tumors

Surgery and radiation therapy are de main treatments for head and neck cancer. The side effects of the interaction of ionizing radiation on the tissues include dermatitis, mucositis, xerostomia, candidiasis, dysgeusia, dysphagia, caries, trismus, osteoradionecrosis. OBJECTIVE: To assess dental condition of the patients using a protocol which allows avoiding or reducing the effects of radiation in the tissues of the oral cavity. MATERIALS AND METHODS: Dental follow-up was performed before, during and up to 180 days after radiation therapy in 12 patients submitted to surgery and radiation therapy or radiation therapy alone. RESULTS: The proportion of effects such as dermatitis, mucositis, dysgeusia, and dysphagia increased from the second week of the treatment until the end of the administrations. There was a clear decrease at the end of the treatment which was close to baseline values after 180 days. The reduction of xerostomia was slower and less effective. No case of caries, trismus, and osteoradionecrosis were observed during the assessment period. CONCLUSION: Regular dental follow-up associated with preventive measures such as prophylactic management of dental and oral diseases, adequate hygiene, mouth-washing with bicarbonate water and chamomile tea, and topic fluorine application contributed to improve the recovery conditions of patients with cancer of head and neck submitted to radiation therapy.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. CONCLUSÃO: 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.UNIFESP-EPMUNIFESP-EPM Departamento de MedicinaUNIFESP-EPM Departamento de Otorrinolaringologia e Cirurgia de Cabeça e PescoçoUNIFESP, EPM, Depto. de MedicinaUNIFESP, EPM Depto. de Otorrinolaringologia e Cirurgia de Cabeça e PescoçoSciEL

RT-PCR analysis of VEGFR2 mRNA expression during endothelial differentiation on the electrospun PHB/PHB-HV fiber mesh and TCPS.

<p>Total RNA was extracted from cells cultured on basal medium and endothelial differentiation medium for analysis of VEGFR2 mRNA expression. The cells were cultivated up to 21 days.</p

Proliferation and viability of hASCs cultured on TCPS and electrospun PHB/PHB-HV fiber mesh.

<p>(A) MTT proliferation assays performed 7, 14 and 21 days after the cell seeding and cultured in two specific medium: the basal medium and the endothelial differentiation medium. The results are expressed as the means ± SD, (*) indicating a significant difference with p<0.05, (**) p<0,01, (***) p<0,001; (B) cell viability after 21 days of cell culture with the basal medium and (C) the endothelial differentiation medium on the electrospun PHB/PHB-HV fiber mesh, as analyzed by Calcein-AM staining.</p

Flow cytometry analysis of hASCs.

<p>The expression pattern of specific antigens on the surface of the hASCs is depicted with representative histograms and the expression of each marker. The cell population expressed CD29, CD44, CD73 and HLA-ABC, and did not express CD34, CD45 and HLA-DR.</p

Protein expression of hASCs during endothelial differentiation.

<p>Confocal images of the expression of the VE-Cadherin (A) and the vWF factor (B) after 21 days. A.1 and B.1 - hASCs cultured with the basal medium on the TCPS coverslips, A.2 and B.2 - hASCs cultured with the endothelial differentiation medium on the TCPS coverslips, A.3 and B.3 - hASCs cultured with the basal medium on the electrospun PHB/PHB-HV fiber mesh, A.4 and B.4 - hASCs cultured with the endothelial differentiation medium on the electrospun PHB/PHB-HV fiber mesh. Scale bar 20 µm. The images, A.2, A.4, B.2 and B.4 represent the overlay of bright-field and confocal images for visualization of the fiber mesh. (C) Fluorescence intensity of the expression of VE-Cadherin and the vWF factor in cells differentiated on TCPS coverslip and electrospun PHB/PHB-HV fiber mesh. The results are expressed as the means ± SD, (*) significant difference for p<0,05. (a.u): arbitrary units.</p