In vivo biocompatibility and safety asessment of a dextrin-based hydrogel for biomedical applications

[Excerpt] Hydrogels are three dimensional, crosslinked networks of hydrophilic polymers swollen with a large amount of water or biological fluids. They can be combined with granules of ceramic-based synthetic bone substitutes (SBSs) aiming to stabilize them into bone defects and to obtain injectable formulations. Our research group has been characterizing a fully resorbable and injectable dextrin-based hydrogel (HG) which was intended to perform as a multifunctional platform, enabling the combination with stem cells and other bioactive agents, during clinical procedures [1-3]. In a subcutaneous assay, the HG was able to incorporate and stabilize ceramic granules (250-500 um) in the implant site, demonstrating its potential as an injectable carrier and stabilizer of SBSs [3]. [...]Isabel Pereira was supported by the grant SFRH/BD/ 90066/2012 from FCT. We thank FEDER and NORTE 2020 through the project nº 003262 titled iBONE therapies: advanced solutions for bone regeneration and NORTE-01-0145-FEDER-000012. We also thank the funding from FCT (UID/BIO/044469/2013 and UID/BIM/04293/2013) and from FEDER through COMPETE 2020 (POCI-01-0145-FEDER-006684).info:eu-repo/semantics/publishedVersio

Modelo impresso em 3D usado num planeamento cirúrgico de um cão com radius curvus

An 8 month-old, 10 kg male Azawakh dog was presented due to worsening forelimb gait and exercise intolerance. The right forelimb presented gross angular limb deformity with carpal valgus and radial procurvatum. Surgical planning based on radiographs allowed calculation of the centers of rotation and angularity (CORAs). The computer tomography data were used to generate 3D reconstructions of the antebrachium to aid the detection of the orthopaedic problems. With proper imaging software, the nature of the deformity and its degree were quantified using a previously unreported method based on the CORAs as a 3D printed model of anatomical area of interest. This 3D printed model was used by the surgeon to simulate the surgery with all orthopaedic steps, which included a partial ulna osteotomy and a double cuneiform osteotomy of the radius performed at the level of CORAs and stabilized with bone plates and screws. After 7 weeks, radiographs revealed bone union. At 8 months after surgery the animal presented a complete recovery of the involved forelimb. CORAs method combined with computed tomography and 3D model was useful to plan and simulate surgical procedures, including the corrective surgery of forelimb deformities in a dog which improved the surgical efficiency comparatively to the conventional pre-operative study.Um cão com 8 meses de idade, 10kg de peso vivo, macho da raça Azawakh foi apresentado à clínica devido à intolerância ao exercício e agravamento da marcha do membro anterior. O membro anterior direito apresentou uma deformidade angular com valgus carpal e com um procarvatum radial. O planeamento cirúrgico inicialmente baseado em exames radiográficos possibilitou o cálculo dos centros de rotação e angulação articulares (CORAs). O exame de tomografia computadorizada foi utilizado juntamente com um software de imagiologia para obter o modelo 3D virtual da área anatómica de interesse que foi posteriormente impresso em 3D e que permitiu quantificar micrometricamente a deformação óssea presente. Este modelo 3D foi utilizado pelos cirurgiões para executar uma simulação cirúrgica completa que englobou todos os procedimentos cirúrgicos, que incluiu a realização de várias osteotomias e aplicação do material cirúrgico (placas e parafusos). Com base na simulação cirúrgica foi executada a cirurgia ao animal. Decorridas sete semanas, as radiografias demonstraram uma correta regeneração óssea. Oito meses após a cirurgia o animal apresentou uma recuperação completa. O método dos CORAs juntamente com a tomografia computadorizada e com a utilização do modelo 3D revelou-se útil no planeamento e na simulação dos vários procedimentos cirúrgicos, resultando numa melhoria significativa da eficiência cirúrgica

Self-mixing microprobe for monitoring microvascular perfusion in rat brain

Measuring functional activity in brain in connection with neural stimulation faces technological challenges. Our goal is to evaluate, in relative terms, the real-time variations of local cerebral blood flow in rat brain, with a convenient spatial resolution. The use of laser Doppler flowmetry (LDF) probes is a promising approach but commercially available LDF probes are still too large (450 mum) to allow insertion in brain tissue without causing damage in an extension that may negatively impact local measurements. The self-mixing technique coupled to LDF is herein proposed to overcome limitations of the minimal diameter of the probe imposed by non-self-mixing probes (commercial available probes). Our Monte Carlo simulations show that laser photons have a mean penetration depth of 0.15 mm, on the rat brain with the 785 nm laser light microprobe. Moreover, three self-mixing signal processing methods are tested: counting method, autocorrelation method, power spectrum method. The perfusion signal computed shows a good linearity with the scatterers velocity, for the three methods (a determination coefficient close to one is obtained), for the in vitro measurements. Furthermore, we believe that these indicators can be used to monitor local blood flow changes in the rat brain

Mesenchymal Stem Cell Studies in the Goat Model for Biomedical Research—A Review of the Scientific Literature

Mesenchymal stem cells (MSCs) are multipotent cells, defined by their ability to self-renew, while maintaining the capacity to differentiate into different cellular lineages, presumably from their own germinal layer. MSCs therapy is based on its anti-inflammatory, immunomodulatory, and regenerative potential. Firstly, they can differentiate into the target cell type, allowing them to regenerate the damaged area. Secondly, they have a great immunomodulatory capacity through paracrine effects (by secreting several cytokines and growth factors to adjacent cells) and by cell-to-cell contact, leading to vascularization, cellular proliferation in wounded tissues, and reducing inflammation. Currently, MSCs are being widely investigated for numerous tissue engineering and regenerative medicine applications. Appropriate animal models are crucial for the development and evaluation of regenerative medicine-based treatments and eventual treatments for debilitating diseases with the hope of application in upcoming human clinical trials. Here, we summarize the latest research focused on studying the biological and therapeutic potential of MSCs in the goat model, namely in the fields of orthopedics, dermatology, ophthalmology, dentistry, pneumology, cardiology, and urology fields

A tissue engineering approach for periodontal regeneration based on a biodegradable double-layer scaffold and adipose-derived stem cells

Human and canine periodontium are often affected by an inflammatory pathology called periodontitis, which isassociated with severe damages across tissues, namely, in the periodontal ligament, cementum, and alveolarbone. However, the therapies used in the routine dental practice, often consisting in a combination of differenttechniques, do not allow to fully restore the functionality of the periodontium. Tissue Engineering (TE) appearsas a valuable alternative approach to regenerate periodontal defects, but for this purpose, it is essential todevelop supportive biomaterial and stem cell sourcing/culturing methodologies that address the complexity ofthe various tissues affected by this condition. The main aim of this work was to study the in vitro functionalityof a newly developed double-layer scaffold for periodontal TE. The scaffold design was based on a combinationof a three-dimensional (3D) fiber mesh functionalized with silanol groups and a membrane, both made of ablend of starch and poly-e-(caprolactone). Adipose-derived stem cells (canine adipose stem cells [cASCs]) wereseeded and cultured onto such scaffolds, and the obtained constructs were evaluated in terms of cellularmorphology, metabolic activity, and proliferation. The osteogenic potential of the fiber mesh layer functionalizedwith silanol groups was further assessed concerning the osteogenic differentiation of the seeded andcultured ASCs. The obtained results showed that the proposed double-layer scaffold supports the proliferationand selectively promotes the osteogenic differentiation of cASCs seeded onto the functionalized mesh. Thesefindings suggest that the 3D structure and asymmetric composition of the scaffold in combination with stemcells may provide the basis for developing alternative therapies to treat periodontal defects more efficiently.The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS. J.F.R. acknowledges the Portuguese Foundation for Science and Technology (FCT) for his PhD scholarship (SFRH/BD/44143/2008)

A multidisciplinary study of Iberian Chalcolithic dogs

Domesticated dogs have been present in the Iberian Peninsula long before other domesticated species, back to the late Palaeolithic period. Their origin is still uncertain, but dogs were already well established during the Chalcolithic period (ca. 5000–4000 BP). This study employed a multidisciplinary approach comprising osteometric, radiographic and palaeogenomic analyses to characterize Chalcolithic Iberian Canis remains. Two Chalcolithic archaeological sites – Leceia, Oeiras, in Portugal, and El Caset´on de la Era, Villalba de los Alcores, Valladolid, in Spain – were the main focus of this study. Osteometric and odontometric data from eleven other sites in Iberia were also included. Osteometric results show signs of phenotypic variability, likely the result of human-driven selective pressure. Dental radiographic and dental wear analyses allowed age at death estimation for four individuals (two juvenile and two adults). Three Chalcolithic Iberian dogs had their mitogenomes resequenced and the mitochondrial DNA analysis allowed to assign each individual to two of the major known haplogroups – A and C. Molecular sex infered by the chromosomeX/chromosome1 coverage ratio allowed to identify one female and two males. This study unveils some aspects of the Iberian Chalcolithic dogs: these dogs already exhibited various morphotypes whose profiles might be associated to the performance of certain tasks, as well as mitogenomes of two distinct lineages that help tracking the evolutionary paths of Iberian dogs.info:eu-repo/semantics/publishedVersio