Background: Tissue engineering and its contribution to regenerative medicine has advanced through the years. It has proven its efficacy especially in the treatment of advanced full thickness burn wounds. Tissue engineering is the synergy between biology and engineering. This fairly young science has one common goal and that is to regenerate new tissue. Various commercially available products have appeared on the market and this due to the ground-breaking work of many. One such well known product is Integra® which is the brain child of Yannas and Burke. This is a collagen-glycosaminoglycan copolymer which serves as a bioactive regeneration template or extracellular matrix analogue. Advanced wound healing is promoted along with the prevention of scar tissue formation and consequent contractures. Aims:</p This study provides an extensive review on the development of this dermal regeneration matrix and also aims to develop an equivalent product. Attention will be paid to: the biological building blocks and the motivation for their use; the essential production steps; and the final processing required in order to deliver a sterile product. Materials and Methods: A collagen and chondroitin 6-sulphate coprecipitate was prepared and subjected to either controlled or uncontrolled freezing. The frozen slurry was dried under vacuum for 17 hours after which each sample was coated with a thin silicone film. Glutaraldehyde crosslinking followed after which the product was thoroughly rinsed. The packaged products were then subjected to terminal sterilisation via gamma irradiation under various conditions. Various tests were conducted to evaluate the newly formed regeneration matrices and included scanning electron microscopy, enzymatic degradation by collagenase, and a cytotoxicity assay. Scanning electron microscopic analysis was done in order to reveal the adequacy of the scaffold architecture. Collagenase degradation of the scaffolds was used to project the rate of degradation of each template. Integra® served as the gold standard for each test. Quantifiable data was statistically analysed and any comparison made included the calculation of means, standard deviations and p-values (confidence interval of 95%). Results: Results indicated that highly porous bioactive tissue engineering matrices were obtained by either controlled freezing or uncontrolled freezing. The average pore diameter of the most homogenous scaffolds ranged between 52.47 and 136.44 µm with a mean of 87.34 µm. These templates were formed by using a 0.5% collagen concentration and a controlled freeze rate of 0.92 °C/min. Uncontrolled freezing (1.3 °C/min) of a 0.5% collagen concentration resulted in the formation of an irregular scaffold with an average pore diameter of 174.08 µm. It was found that the architecture of the most equivalent scaffold compared well with that of Integra® with p = 0.424. Scaffolds prepared using higher collagen concentrations (1.0%) and controlled freezing resulted in dense sponges with average pore diameters of 56.51 µm. Statistical analysis upon comparison indicated a significant difference p = 0.000 in the micro architecture. The rate of degradation of the most equivalent scaffold was 1.9 times that of Integra®. This implicates that the crosslinking was insufficient and due to one of the following: poor collagen quality; method of crosslinking; and degradation due to terminal sterilization. The rate of scaffold degradation can be extended, either by additional crosslinking or the prevention of degradation induced by irradiation. Temperature vacuum dehydration crosslinking through esterification or amide formation can be used as an initial crosslinking method in further studies. This form of crosslinking will complete the conventional glutaraldehyde crosslinking that reacts with the free amine groups of lysine or hydroxylysine of the protein backbone of collagen. It should be stressed that the determination of an in vivo degradation rate, in the form of an animal study, will aid to confirm the efficacy of the biologically active regeneration matrix. / Dissertation (MSc)--University of Pretoria, 2008. / Anatomy / unrestricted

Orientador: Maria Helena Andrade Santana / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-27T09:34:05Z (GMT). No. of bitstreams: 1 Shimojo_AndreaArrudaMartins_D.pdf: 2752681 bytes, checksum: 11e9996d95e39a313bd958eee397ff40 (MD5) Previous issue date: 2015 / Resumo: Este trabalho teve como objetivo estudar o desempenho in vitro do plasma rico em plaquetas (PRP) com scaffolds de ácido hialurônico (AH) ou quitosana (CHT) como um scaffold compósito para a proliferação e diferenciação osteogênica de células tronco mesenquimais derivadas de tecido adiposo humano (h-AdMSCs). O PRP é um produto autólogo obtido do sangue total (WB). O ácido hialurônico é um glicosaminoglicano e principal componente do fluido sinovial. A quitosana é um polissacarídeo natural encontrado principalmente na carapaça de crustáceos. O PRP puro (P-PRP, rico em plaquetas e pobre em leucócitos) foi obtido a partir da centrifugação controlada do WB, e ativado com os agonistas soro autólogo e cálcio. Os scaffolds foram estruturados em micropartículas ou esponjas, para atender os requisitos de formulações injetáveis ou sólidas, respectivamente. Nesse contexto, os seguintes scaffolds foram preparados e caracterizados: sólidos porosos (esponjas) de quitosana não estabilizados (PCHTs) e estabilizados (SPCHTs); micropartículas de quitosana-tripolifosfato de sódio (iCHT-TPPs); micropartículas e esponjas de ácido hialurônico autorreticulado (ACPs) e de ácido hialurônico reticulado com 1,4-butanodiol diglicidil éter (HA-BDDE); e esponjas e micropartículas de ACP e CHT (PECs). PCHTs foram preparados por congelamento e liofilização de soluções de CHT, variando a concentração e as condições de congelamento. As estabilizações foram realizadas pelo tratamento dos PCHTs com hidróxido de sódio, série de etanol ou reticulação com tripolifosfato. Os iCHT-TPPs foram preparados por reticulação iônica de quitosana com TPP em diferentes razões mássicas. ACPs foram obtidos por autoesterificação organocatalisada. HA-BDDE foi preparado por eterificação dos grupos hidroxílicos do HA com o epóxido BDDE. PECs foram preparados por reticulação iônica do ACP com a CHT. Para a preparação de scaffolds compósitos, P-PRP ativado contendo h-AdMSCs foi imediatamente pipetado sobre a superfície dos scaffolds. Os resultados mostraram que os scaffolds não apresentam citotoxicidade. Micrografias obtidas por microscopia eletrônica de varredura mostraram compatibilidade estrutural com as redes de fibrina formadas no interior dos poros ou na superfície de scaffolds compósitos. Os scaffolds compósitos estimularam o crescimento de h-AdMSCs e a diferenciação osteogênica. Os scaffolds compósitos também promoveram liberação gradual dos fatores de crescimento PDGF-AB e TGF-?1. Assim, concluímos que os scaffolds compósitos estudados neste trabalho são promissores para engenharia de tecidos, particularmente para a cicatrização e regeneração óssea, no âmbito da medicina regenerativa / Abstract: This work aimed to study the in vitro performance of platelet-rich plasma (PRP) with scaffolds of hyaluronic acid (HA) and/ or chitosan (CHT) as a composite scaffold for proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells (h-AdMSCs). The PRP is an autologous product obtained from whole blood (WB). Hyaluronic acid is a glycosaminoglycan and the main component of the synovial fluid. Chitosan is a natural polysaccharide found mainly in the carapace of crustaceans. The pure PRP (P-PRP, rich in platelet and poor in leukocytes) was obtained from controlled centrifugation of WB, and activated with the agonists autologous serum and calcium. The scaffolds were structured in microparticles or sponges, to comply the requirements of injectable or solid formulations, respectively. In this context, the following scaffolds were prepared and characterized: chitosan porous solid (sponge) unstabilized (PCHTs) and stabilized (SPCHTs); chitosan-sodium tripolyphosphate microparticles (iCHT-TPPs); microparticles and sponges of auto-crosslinked hyaluronic acid (ACPs) and of hyaluronic acid crosslinked with 1,4-butanediol diglycidyl ether (HA-BDDE); and microparticles and sponges of ACP and CHT (PECs). PCHTs were prepared by freezing and lyophilization of CHT solutions, varying the concentration and freezing conditions. Stabilization was performed by treating the PCHTs with sodium hydroxide, an ethanol series or by crosslinking with tripolyphosphate. The iCHT-TPPs were prepared by ionic crosslinking of chitosan with TPP at different mass ratios. ACPs was prepared by organocatalyzed auto-esterification. HA-BDDE was prepared by etherification of the hydroxyl groups of HA with the epoxide BDDE. PECs were prepared by ionic crosslinking of ACP with CHT. For the preparation of composite scaffolds, activated P-PRP containing h-AdMSCs was immediately pipetted onto the surface of the scaffolds. The results showed that the scaffolds do not exhibit cytotoxicity. Micrographs obtained by scanning electron microscopy (SEM) showed structural compatibility with fibrin networks formed inside the pores or on the surface of scaffolds. The composite scaffolds stimulated the growth of h-AdMSCs and osteogenic differentiation. Composite scaffolds also promoted gradual release of growth factors PDGF-AB and TGF-?1 and osteogenic differentiation. Thus, we conclude that the composite scaffolds studied in this work are promising for tissue engineering, particularly for healing and bone regeneration in regenerative medicine / Doutorado / Engenharia Química / Doutora em Engenharia Quimica

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23602号 / 医博第4789号 / 新制||医||1055(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 長船 健二, 教授 川口 義弥, 教授 大森 孝一 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(医科学) / 甲第24885号 / 医科博第152号 / 新制||医科||10(附属図書館) / 京都大学大学院医学研究科医科学専攻 / (主査)教授 河本 宏, 教授 濵﨑 洋子, 教授 上野 英樹 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Degenerated intervertebral discs (IVDs) were treated with autologous adipose-derived stem cells (ASC) loaded into an injectable collagen scaffold in a sheep model to investigate the implant's therapeutic potential regarding the progression of degeneration of previously damaged discs. In this study, 18 merino sheep were subjected to a 3-step minimally invasive injury and treatment model, which consisted of surgically induced disc degeneration, treatment of IVDs with an ASC-loaded collagen hydrogel 6 weeks post-operatively, and assessment of the implant's influence on degenerative tissue changes after 6 and 12 months of grazing. Autologous ASCs were extracted from subcutaneous adipose tissue and cultivated in vitro. At the end of the experiment, disc heights were determined by µ-CT measurements and morphological tissue changes were histologically examined.Histological investigations show that, after treatment with the ASC-loaded collagen hydrogel implant, degeneration-specific features were observed less frequently. Quantitative studies of the degree of degeneration did not demonstrate a significant influence on potential tissue regeneration with treatment. Regarding disc height analysis, at both 6 and 12 months after treatment with the ASC-loaded collagen hydrogel implant a stabilization of the disc height can be seen. A complete restoration of the intervertebral disc heights however could not be achieved.The reported injection procedure describes in a preclinical model a translational therapeutic approach for degenerative disc diseases based on adipose-derived stem cells in a collagen hydrogel scaffold. Further investigations are planned with the use of a different injectable scaffold material using the same test model.

Background: Regenerative therapies based on autologous mesenchymal stem cells (MSC) as well as stem cells in general are still facing an unmet need for non-invasive sampling, availability, and scalability. The only known adult source of autologous MSCs permanently available with no pain, discomfort, or infection risk is the outer root sheath of the hair follicle (ORS). Methods: This study presents a non-invasively-based method for isolating and expanding MSCs from the ORS (MSCORS) by means of cell migration and expansion in air–liquid culture. Results: The method yielded 5 million cells of pure MSCORS cultured in 35 days, thereby superseding prior art methods of culturing MSCs from hair follicles. MSCORS features corresponded to the International Society for Cell Therapy characterization panel for MSCs: adherence to plastic, proliferation, colony forming, expression of MSC-markers, and adipo-, osteo-, and chondro-differentiation capacity. Additionally, MSCORS displayed facilitated random-oriented migration and high proliferation, pronounced marker expression, extended endothelial and smooth muscle differentiation capacity, as well as a paracrine immunomodulatory effect on monocytes. MSCORS matched or even exceeded control adipose-derived MSCs in most of the assessed qualities. Conclusions: MSCORS qualify for a variety of autologous regenerative treatments of chronic disorders and prophylactic cryopreservation for purposes of acute treatments in personalized medicine.

Tissues arising late in evolutionary time, such as lung alveoli that are unique to air breathing organisms, have been challenging to generate in vitro from pluripotent stem cells (PSCs), in part because there are limited lower organism model systems available to provide the necessary developmental roadmaps to guide in vitro differentiation. Furthermore, pulmonary alveolar epithelial type II cell (AEC2) dysfunction has been implicated as a primary cause of pathogenesis in many poorly understood lung diseases that lack effective therapies, including interstitial lung disease (ILD) and emphysema. Here we report the successful directed differentiation in vitro of human PSCs into AEC2s, the facultative progenitors of lung alveoli. Using gene editing to engineer multicolored fluorescent reporter PSC lines (NKX2-1GFP;SFTPCtdTomato), we track and purify human SFTPC+ alveolar progenitors as they emerge from NKX2-1+ endodermal developmental precursors in response to stimulation of Wnt and FGF signaling. Purified PSC-derived SFTPC+ cells are able to form monolayered epithelial spheres (“alveolospheres”) in 3D cultures without the need for mesenchymal co-culture support, exhibit extensive self-renewal capacity, and display additional canonical AEC2 functional capacities, including innate immune responsiveness, the production of lamellar bodies able to package surfactant, and the ability to undergo squamous cell differentiation while upregulating type 1 alveolar cell markers. Guided by time-series global transcriptomic profiling we find that AEC2 maturation involves downregulation of Wnt signaling activity, and the highest differentially expressed transcripts in the resulting SFTPC+ cells encode genes associated with lamellar body and surfactant biogenesis. Finally, we apply this novel model system to generate patient-specific AEC2s from induced PSCs (iPSCs) carrying homozygous surfactant mutations (SFTPB121ins2), and we employ footprint-free CRISPR-based gene editing to observe that correction of this genetic lesion restores surfactant processing in the cells responsible for their disease. Thus we provide an approach for disease modeling and future functional regeneration of a cell type unique to air-breathing organisms.

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