Chitosan/polyester-based scaffolds for cartilage tissue engineering: assessment of extracellular matrix formation

Naturally derived polymers have been extensively used in scaffold production for cartilage tissue engineering. The present work aims to evaluate and characterize extracellular matrix (ECM) formation in two types of chitosan-based scaffolds, using bovine articular chondrocytes (BACs). The influence of these scaffolds’ porosity, as well as pore size and geometry, on the formation of cartilagineous tissue was studied. The effect of stirred conditions on ECM formation was also assessed. Chitosan-poly(butylene succinate) (CPBS) scaffolds were produced by compression moulding and salt leaching, using a blend of 50% of each material. Different porosities and pore size structures were obtained. BACs were seeded onto CPBS scaffolds using spinner flasks. Constructs were then transferred to the incubator, where half were cultured under stirred conditions, and the other half under static conditions for 4 weeks. Constructs were characterized by scanning electron microscopy, histology procedures, immunolocalization of collagen type I and collagen type II, and dimethylmethylene blue assay for glycosaminoglycan (GAG) quantification. Both materials showed good affinity for cell attachment. Cells colonized the entire scaffolds and were able to produce ECM. Large pores with random geometry improved proteoglycans and collagen type II production. However, that structure has the opposite effect on GAG production. Stirred culture conditions indicate enhancement of GAG production in both types of scaffold.M.L. Alves da Silva would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for her grant (SFRH/BD/28708/2006), Marie Curie Actions-ALEA JACTA EST (MEST-CT-2004-008104), European NoE EXPERTISSUES (NMP3-CT-2004-500283), IP GENOSTEM (LSHB-CT-2003-503161) and CARTISCAFF (POCTI/SAUIBMA/58982

Epidermis recreation in spongy-like hydrogels: New opportunities to explore epidermis-like analogues

[Excerpt] On the road to successfully achieving skin regeneration, 3D matrices/scaffolds that provide the adequate physico-chemical and biological cues to recreate the ideal healing environment are believed to be a key element [1], [2] and [3]. Numerous polymeric matrices derived from both natural [4] and [5] and synthetic [6], [7] and [8] sources have been used as cellular supports; nowadays, fewer matrices are simple carriers, and more and more are ECM analogues that can actively participate in the healing process. Therefore, the attractive characteristics of hydrogels, such as high water content, tunable elasticity and facilitated mass transportation, have made them excellent materials to mimic cells’ native environment [9]. Moreover, their hygroscopic nature [10] and possibility of attaining soft tissues-like mechanical properties mean they have potential for exploitation as wound healing promoters [11], [12], [13] and [14]. Nonetheless, hydrogels lack natural cell adhesion sites [15], which limits the maximization of their potential in the recreation of the cell niche. This issue has been tackled through the use of a range of sophisticated approaches to decorate the hydrogels with adhesion sequences such as arginine-glycine-aspartic acid (RGD) derived from fibronectin [16], [17] and [18], and tyrosine-isoleucine-glycine-serine-arginine (YIGSR) derived from laminin [18] and [19], which not only aim to modulate cell adhesion, but also influencing cell fate and survival [18]. Nonetheless, its widespread use is still limited by significant costs associated with the use of recombinant bioactive molecules

ΑΓΕΛΑΔΙΝΟ ΠΡΩΤΟΓΑΛΑ ΒΕΛΤΙΩΝΕΙ ΤΗΝ ΟΣΤΙΚΗ ΜΙΚΡΟΔΟΜΗ ΤΩΝ ΑΡΟΥΡΑΙΩΝ ΜΕ ΩΟΘΗΚΕΚΤΟΜΗ ΚΑΙ ΟΡΧΕΚΤΟΜΗ

Το αγελαδινό πρωτόγαλα ενισχύει τον αναβολισμό των οστών, ωστόσο ο ακριβής μηχανισμός δεν είναι γνωστός. Σκοπός μελέτης: Η εκτίμηση της επίδρασης διαφορετικών δόσεων πρωτογάλακτος σε αρουραίους με ωοθηκεκτομή και ορχεκτομή και ο προσδιορισμός του μηχανισμού επίδρασής του στα οστά. Αγελαδινό πρωτόγαλα χορηγήθηκε σε θηλυκούς (n=32) και αρσενικούς (n=32) αρουραίους που τυχαιοποιήθηκαν στις α) ομάδα ελέγχου (ΟΕ), β) ομάδα 1 (Ο1) (θηλυκοί=0.5 gr/μέρα, αρσενικοί=1.0 gr/μέρα), γ) ομάδα 2 (Ο2) (θηλυκοί=1 gr/μέρα, αρσενικοί= 1.5 gr/μέρα) και δ) ομάδα 3 (Ο3) (θηλυκοί=1.5 gr/μέρα, αρσενικοί= 2.0 gr/μέρα). Η οστική μικροαρχιτεκτονική και η γονιδιακή έκφραση του παράγοντα VEGF-A, μετρήθηκαν πριν και μετά από 4μηνη χορήγηση. Στους αρσενικούς αρουραίους της Ο1, η πορώδης σύσταση του φλοιού και το μέγεθος των πόρων μειώθηκαν (41.9% και 25.7% αντίστοιχα, p<0.05) σε σχέση με την ΟΕ, ενώ παρατηρήθηκε αύξηση του φλοιώδους όγκου και πυκνότητας (89.7% και 134.9% αντίστοιχα, p<0.01) και του δοκιδωτού πάχους, όγκου και πυκνότητας (37.3%, 24.6% και 7.5% αντίστοιχα, p<0.01) μετά τη χορήγηση. Στην Ο2 παρατηρήθηκαν παρόμοια αποτελέσματα, ενώ το δοκιδωτό πορώδες μειώθηκε (8.1%, p<0.01). Στην Ο3 μειώθηκε ο δοκιδωτός διαχωρισμός (29.3%, p<0.05). Στους θηλυκούς αρουραίους της Ο1 δεν παρατηρήθηκαν αλλαγές μετά τη χορήγηση, ωστόσο στις Ο2 και Ο3 μειώθηκε η σύσταση του πορώδους φλοιού (ΟΕ= 65.75±4.22. Ο2= 25.16±8.83. Ο3=25.22±8.54%, p<0.01) και βελτιώθηκε το δοκιδωτό πάχος (ΟΕ=12.22±0.99; Ο2=21.11±3.28; Ο3=18.39±2.45 μm, p<0.01). επίσης, στην Ο3 παρουσιάστηκε αύξηση της γονιδιακής έκφρασης του VEGFA (2.37±1.83, p<0.05). Το αγελαδινό πρωτόγαλα διατηρεί την οστική μάζα των αρουραίων με ωοθηκεκτομή και ορχεκτομή, ενισχύοντας τον οστικό σχηματισμό. Ο παράγοντας VEGF-A φαίνεται να παίζει σημαντικό ρόλο στη διαδικασία

Pharmacological and Non-Pharmacological Agents versus Bovine Colostrum Supplementation for the Management of Bone Health Using an Osteoporosis-Induced Rat Model

Osteoporosis is defined by loss of bone mass and deteriorated bone microarchitecture. The present study compared the effects of available pharmacological and non-pharmacological agents for osteoporosis [alendronate (ALE) and concomitant supplementation of vitamin D (VD) and calcium (Ca)] with the effects of bovine colostrum (BC) supplementation in ovariectomized (OVX) and orchidectomized (ORX) rats. Seven-month-old rats were randomly allocated to: (1) placebo-control, (2) ALE group (7.5 μg/kg of body weight/day/5 times per week), (3) VD/Ca group (VD: 35 μg/kg of body weight/day/5 times per week; Ca: 13 mg/kg of body weight/day/3 times per week), and (4) BC supplementation (OVX: 1.5 g/day/5 times per week; ORX: 2 g/day/5 times per week). Following four months of supplementation, bone microarchitecture, strength and bone markers were evaluated. ALE group demonstrated significantly higher Ct.OV, Ct.BMC, Tb.Th, Tb.OV and Tb.BMC and significantly lower Ct.Pr, Tb.Pr, Tb.Sp, Ct.BMD and Tb.BMD, compared to placebo (p < 0.05). BC presented significantly higher Ct.Pr, Ct.BMD, Tb.Pr, Tb.Sp, and Tb.BMD and significantly lower Ct.OV, Ct.BMC, Tb.Th, Tb.OV and Tb.BMC compared to ALE in OVX rats (p < 0.05). OVX rats receiving BC experienced a significant increase in serum ALP and OC levels post-supplementation (p < 0.05). BC supplementation may induce positive effects on bone metabolism by stimulating bone formation, but appear not to be as effective as ALE. © 2022 by the authors

Bovine colostrum supplementation improves bone metabolism in an osteoporosis-induced animal model

Osteoporosis is characterized by bone loss. The present study aims to investigate the effects of bovine colostrum (BC) on bone metabolism using ovariectomized (OVX) and orchidec-tomized (ORX) rat models. Twenty-seven-week-old Wistar Han rats were randomly assigned as: (1) placebo control, (2) BC supplementation dose 1 (BC1: 0.5 g/day/OVX, 1 g/day/ORX), (3) BC sup-plementation dose 2 (BC2: 1 g/day/OVX, 1.5 g/day/ORX) and (4) BC supplementation dose 3 (BC3: 1.5 g/day/OVX, 2 g/day/ORX). Bone microarchitecture, strength, gene expression of VEGFA, FGF2, RANKL, RANK and OPG, and bone resorption/formation markers were assessed after four months of BC supplementation. Compared to the placebo, OVX rats in the BC1 group exhibited significantly higher cortical bone mineral content and trabecular bone mineral content (p < 0.01), while OVX rats in the BC3 group showed significantly higher trabecular bone mineral content (p <0.05). ORX rats receiving BC dose 2 demonstrated significantly higher levels of trabecular bone mineral content (p < 0.05). Serum osteocalcin in the ORX was pointedly higher in all BC supplementation groups than the placebo (BC1: p < 0.05; BC2, BC3: p < 0.001). Higher doses of BC induced significantly higher relative mRNA expression of OPG, VEGFA, FGF2 and RANKL (p < 0.05). BC supplementation improves bone metabolism of OVX and ORX rats, which might be associated with the activation of the VEGFA, FGF2 and RANKL/RANK/OPG pathways. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Organ-on-chip models of cancer metastasis for future personalized medicine: from chip to the patient

Most cancer patients do not die from the primary tumor but from its metastasis. Current in vitro and in vivo cancer models are incapable of satisfactorily predicting the outcome of various clinical treatments on patients. This is seen as a serious limitation and efforts are underway to develop a new generation of highly predictive cancer models with advanced capabilities. In this regard, organ-on-chip models of cancer metastasis emerge as powerful predictors of disease progression. They offer physiological-like conditions where the (hypothesized) mechanistic determinants of the disease can be assessed with ease. Combined with high-throughput characteristics, the employment of organ-on-chip technology would allow pharmaceutical companies and clinicians to test new therapeutic compounds and therapies. This will permit the screening of a large battery of new drugs in a fast and economic manner, to accelerate the diagnosis of the disease in the near future, and to test personalized treatments using cells from patients. In this review, we describe the latest advances in the field of organ-on-chip models of cancer metastasis and their integration with advanced imaging, screening and biosensing technologies for future precision medicine applications. We focus on their clinical applicability and market opportunities to drive us forward to the next generation of tumor models for improved cancer patient theranostics.- The authors acknowledge the financial support from the European Union Framework Programme for Research and Innovation Horizon 2020 on Forefront Research in 3D Disease Cancer Models as in vitro Screening Technologies (FoReCaST) under grant agreement no 668983. Conflicts of interest: none.info:eu-repo/semantics/publishedVersio

Bioceramics for osteochondral tissue engineering and regeneration

Considerable advances in tissue engineering and regeneration have been accomplished over the last decade. Bioceramics have been developed to repair, reconstruct, and substitute diseased parts of the body and to promote tissue healing as an alternative to metallic implants. Applications embrace hip, knee, and ligament repair and replacement, maxillofacial reconstruction and augmentation, spinal fusion, bone filler, and repair of periodontal diseases. Bioceramics are well-known for their superior wear resistance, high stiffness, resistance to oxidation, and low coefficient of friction. These specially designed biomaterials are grouped in natural bioceramics (e.g., coral-derived apatites), and synthetic bioceramics, namely bioinert ceramics (e.g., alumina and zirconia), bioactive glasses and glass ceramics, and bioresorbable calcium phosphates-based materials. Physicochemical, mechanical, and biological properties, as well as bioceramics applications in diverse fields of tissue engineering are presented herein. Ongoing clinical trials using bioceramics in osteochondral tissue are also considered. Based on the stringent requirements for clinical applications, prospects for the development of advanced functional bioceramics for tissue engineering are highlighted for the future.The authors acknowledge the project FROnTHERA (NORTE-01-0145- FEDER-000023), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). Also, H2020-MSCA-RISE program, as this work is part of developments carried out in BAMOS project, funded from the European Union’s Horizon 2020 research and innovation program under grant agreement N° 734156. The financial support from the Portuguese Foundation for Science and Technology for the funds provided under the program Investigador FCT 2012, 2014, and 2015 (IF/00423/2012, IF/01214/2014, and IF/01285/2015) is also greatly acknowledged.info:eu-repo/semantics/publishedVersio