Role of IGF1 and IGF1/VEGF on Human Mesenchymal Stromal Cells in Bone Healing: Two Sources and Two Fates.

In the repair of skeletal defects one of the major obstacles still remains an efficient vascularization of engineered scaffolds. We have examined the ability of insulin growth factor-1, alone or in association with vascular endothelial growth factor, to modulate the osteoblastic or endothelial commitment of periosteum-derived progenitor cells (PDPCs) and skin-derived multipotent stromal cells (S-MSCs). A selected gene panel for endothelial and osteoblastic differentiation as well as genes that can affect MAPK and PI3K/AKT signaling pathways were investigated. Moreover, gene expression profile of Sox2, Oct4, and Nanog transcription factors was assessed. Our results showed that under growth factor stimulation PDPCs are induced toward an osteoblastic differentiation, while S-MSCs seem to move along an endothelial phenotype. This different commitment seems to be linked to a diverse MAPK or PI3K/AKT signaling pathway activation. The analysis of genes for stemness evidenced that at least in PDPCs multipotency and differentiation could coexist. These results open interesting perspective for the development of innovative bone tissue engineering approaches based on a good network of angiogenesis and osteogenesis processes

The effects of ageing on dental pulp stem cells, the tooth longevity elixir

Stem cells are essential for tissue homeostasis and regeneration throughout the lifespan of multicellular rganisms. The decline in stem cell function during advanced age is associated with a reduced regenerative potential of tissues that leads to an increased frequency of diseases. Age-related changes also occur in the dental pulp tissue that represents a reliable model tissue, with high regenerative capability, for studying senescence mechanisms. However, little information is available concerning the effects of ageing on dental stem-cell function. In this mini-review, recent data on how the molecular and functional alterations that accumulate in stem cell populations during ageing result in modifications of dental pulp physiology are discussed. Changes that accumulate during ageing such as how reduction of pulp chamber volume, decreased vascular supply and modifications to the stem cell niches affect stem cell functions and, therefore, dental pulp regenerative potential in response to various stressful agents. Dental pulp cells from aged individuals are still metabolically active and secrete pro-inflammatory and matrix-degrading molecules. Furthermore, miRNAs and exosomes derived from dental pulp stem cells constitute an attractive source of nanovesicles for the treatment of age-related dental pathologies. Further investigation of the epigenetic alterations in dental pulp stem cells, accumulating during ageing, might reveal crucial information for potential stem cell-based therapeutic approaches in the elderly

Innovative eco-friendly hydrogel film for berberine delivery in skin applications†

Hydrogel formulations (masks or patches, without tissue support) represent the new frontier for customizable skin beauty and health. The employment of these materials is becoming popular in wound dressing, to speed up the healing process while protecting the affected area, as well as to provide a moisturizing reservoir, control the inflammatory process and the onset of bacterial development. Most of these hydrogels are acrylic-based at present, not biodegradable and potentially toxic, due to acrylic monomers residues. In this work, we selected a new class of cellulose-derived and biodegradable hydrogel films to incorporate and convey an active compound for dermatological issues. Films were obtained from a combination of different polysaccharides and clays, and berberine hydrochloride, a polyphenolic molecule showing anti-inflammatory, immunomodulatory, antibacterial and antioxidant properties, was chosen and then embedded in the hydrogel films. These innovative hydrogel-based systems were characterized in terms of water uptake profile, in vitro cytocompatibility and skin permeation kinetics by Franz diffusion cell. Berberine permeation fitted well to Korsmeyer–Peppas kinetic model and achieved a release higher than 100 µg/cm2 within 24 h. The latter study, exploiting a reliable skin model membrane, together with the biological assessment, gained insights into the most promising formulation for future investigations

Adult mesenchymal stem cells for bone and cartilage engineering: effect of scaffold materials

Bone marrow is a useful cell source for skeletal tissue engineering approaches. In vitro differentiation of marrow mesenchymal stem cells (MSCs) to chondrocytes or osteoblasts can be induced by the addition of specific growth factors to the medium. The present study evaluated the behaviour of human MSCs cultured on various scaffolds to determine whether their differentiation can be induced by cell-matrix interactions. MSCs from bone marrow collected from the acetabulum during hip arthroplasty procedures were isolated by cell sorting, expanded and characterised by a flow cytometry system. Cells were grown on three different scaffolds (type I collagen, type I + II collagen and type I collagen + hydroxyapatite membranes) and analysed by histochemistry, immunohistochemistry and spectrophotometry (cell proliferation, alkaline phosphatase activity) at 15 and 30 days. Widely variable cell adhesion and proliferation was observed on the three scaffolds. MSCs grown on type I+II collagen differentiated to cells expressing chondrocyte markers, while those grown on type I collagen + hydroxyapatite differentiated into osteoblast-like cells. The study highlighted that human MSCs grown on different scaffold matrices may display different behaviours in terms of cell proliferation and phenotype expression without growth factor supplementation

MicroRNA networks direct neuronal development and plasticity

MicroRNAs (miRNAs) constitute a class of small, non-coding RNAs that act as post-transcriptional regulators of gene expression. In neurons, the functions of individual miRNAs are just beginning to emerge, and recent studies have elucidated roles for neural miRNAs at various stages of neuronal development and maturation, including neurite outgrowth, dendritogenesis, and spine formation. Notably, miRNAs regulate mRNA translation locally in the axosomal and synaptodendritic compartments, and thereby contribute to the dynamic spatial organization of axonal and dendritic structures and their function. Given the critical role for miRNAs in regulating early brain development and in mediating synaptic plasticity later in life, it is tempting to speculate that the pathology of neurological disorders is affected by altered expression or functioning of miRNAs. Here we provide an overview of recently identified mechanisms of neuronal development and plasticity involving miRNAs, and the consequences of miRNA dysregulation

Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)