The Hypoxia-Mimetic Agent Cobalt Chloride Differently Affects Human Mesenchymal Stem Cells in Their Chondrogenic Potential

Adult stem cells are a promising cell source for cartilage regeneration. They resided in a special microenvironment known as the stem-cell niche, characterized by the presence of low oxygen concentration. Cobalt chloride (CoCl2) imitates hypoxia in vitro by stabilizing hypoxia-inducible factor-alpha (HIF-1α), which is the master regulator in the cellular adaptive response to hypoxia. In this study, the influence of CoCl2 on the chondrogenic potential of human MSCs, isolated from dental pulp, umbilical cord, and adipose tissue, was investigated. Cells were treated with concentrations of CoCl2 ranging from 50 to 400 μM. Cell viability, HIF-1α protein synthesis, and the expression of the chondrogenic markers were analyzed. The results showed that the CoCl2 supplementation had no effect on cell viability, while the upregulation of chondrogenic markers such as SOX9, COL2A1, VCAN, and ACAN was dependent on the cellular source. This study shows that hypoxia, induced by CoCl2 treatment, can differently influence the behavior of MSCs, isolated from different sources, in their chondrogenic potential. These findings should be taken into consideration in the treatment of cartilage repair and regeneration based on stem cell therapies

The hypoxia-mimetic agent cobalt chloride differently affects human mesenchymal stem cells in their chondrogenic potential

Adult stem cells are a promising cell source for cartilage regeneration. They resided in a special microenvironment known as the stem-cell niche, characterized by the presence of low oxygen concentration. Cobalt chloride (CoCl2) imitates hypoxia in vitro by stabilizing hypoxia-inducible factor-alpha (HIF-1\ue1), which is the master regulator in the cellular adaptive response to hypoxia. In this study, the influence of CoCl2 on the chondrogenic potential of human MSCs, isolated from dental pulp, umbilical cord, and adipose tissue, was investigated. Cells were treated with concentrations of CoCl2 ranging from 50 to 400 \uecM. Cell viability, HIF-1\ue1 protein synthesis, and the expression of the chondrogenic markers were analyzed. The results showed that the CoCl2 supplementation had no effect on cell viability, while the upregulation of chondrogenic markers such as SOX9, COL2A1, VCAN, and ACAN was dependent on the cellular source. This study shows that hypoxia, induced by CoCl2 treatment, can differently influence the behavior of MSCs, isolated from different sources, in their chondrogenic potential. These findings should be taken into consideration in the treatment of cartilage repair and regeneration based on stem cell therapies

Implication of Cellular Senescence in Osteoarthritis: A Study on Equine Synovial Fluid Mesenchymal Stromal Cells

: Osteoarthritis (OA) is described as a chronic degenerative disease characterized by the loss of articular cartilage. Senescence is a natural cellular response to stressors. Beneficial in certain conditions, the accumulation of senescent cells has been implicated in the pathophysiology of many diseases associated with aging. Recently, it has been demonstrated that mesenchymal stem/stromal cells isolated from OA patients contain many senescent cells that inhibit cartilage regeneration. However, the link between cellular senescence in MSCs and OA progression is still debated. In this study, we aim to characterize and compare synovial fluid MSCs (sf-MSCs), isolated from OA joints, with healthy sf-MSCs, investigating the senescence hallmarks and how this state could affect cartilage repair. Sf-MSCs were isolated from tibiotarsal joints of healthy and diseased horses with an established diagnosis of OA with an age ranging from 8 to 14 years. Cells were cultured in vitro and characterized for cell proliferation assay, cell cycle analysis, ROS detection assay, ultrastructure analysis, and the expression of senescent markers. To evaluate the influence of senescence on chondrogenic differentiation, OA sf-MSCs were stimulated in vitro for up to 21 days with chondrogenic factors, and the expression of chondrogenic markers was compared with healthy sf-MSCs. Our findings demonstrated the presence of senescent sf-MSCs in OA joints with impaired chondrogenic differentiation abilities, which could have a potential influence on OA progression

Comparative characterization of human and equine Wharton’s jelly derived mesenchymal stem cells

Mesenchymal stem cells (MSCs) have the capability to differentiate into wide range of specialized cells of mesodermal origin such as osteocytes, chondrocytes, adipocytes, cardiomyocytes, muscle fibers. Due to these properties, MSCs are considered as a new emerging treatment option and therapeutic agent in regenerative medicine. Promising results have been obtained after application of MSCs for treating tendon and joint disease in the equine model, making it favorable for therapeutic application. While the horse is considered a highly suitable model for orthopedic diseases, knowledge is lacking regarding the level of analogy of equine MSCs and their human counterparts. Therefore, the aim of this study was to assess the properties of human and equine Wharton’s jelly derived MSCs in a direct comparison. Obtained MSCs, were characterized for their staminal markers, proliferation and adhesion potential, ultrastructural morphology and their ability in differentiate towards osteogenic, chondrogenic and adipogenic lineages. Results showed a similar pattern in the expression of staminal markers, while a light difference was observed in the proliferation and adhesion potential. Ultramorphological analysis showed nuclear and citoplasmatic features comparable in human and equine MSCs. Finally, both MSCs were able to differentiate towards osteogenic, chondrogenic and adipogenic lineages. In conclusion, although revealing some potentially relevant differences, the study demonstrates a high level of analogy between human and equine MSCs, providing a basis for translational research in the equine model

Cobalt chloride supplementation differently affects human mesenchymal stem cells isolated from dental pulp, umbilical cord and adipose tissues in their chondrogenic potential

Articular cartilage is an avascular tissue without innervations, characterized by low cell density and abundant extracellular matrix (ECM). These characteristics leave articular cartilage with very limited capacity of repair and regeneration. Multipotent stem/stromal cells (MSC) are considered promising for cartilage tissue engineering. Stem cells are resided in a special microenvironment known as the stem-cell niche, characterized by the presence of low oxygen concentration. Previous studies have reported that hypoxic conditions could enhance the chondrogenic differentiation of mesenchymal stem cells in the presence of an inductive medium. Cobalt chloride (CoCl2) imitates hypoxia in vitro by preventing hypoxia-inducible factor-alpha (HIF-a) from being destroyed by oxygen. However, the long-term hypoxic culture of stem cells is difficult and requires special attention to avoid cell death due to cobalt treatment. In this study we investigated if CoCl2 affected MSCs isolated from dental pulp, umbilical cord and adipose tissue in their potential to differentiate toward the chondrogenic phenotype. Cells were treated with concentrations of CoCl2 ranging from 50 to 400 uM. Cell proliferation, mRNA expression of stem-cell marker and chondrogenic associated genes were analyzed by RT-PCR and Real-time PCR. The results showed that the CoCl2 supplementation had no effect on the proliferation of all the three type of cells analyzed, while the up-regulation of chondrogenic markers such as aggrecan, sox9, and type II collagen, was dependent on the cellular source. This study shows that hypoxia induced by CoCl2 treatment can differently influence the behavior of MSCs of different sources in their chondrogenic potential. These findings should be taken into consideration in the treatment of cartilage repair and regeneration based on stem cell therapies

Tendon Healing Response Is Dependent on Epithelial–Mesenchymal–Tendon Transition State of Amniotic Epithelial Stem Cells

Tendinopathies are at the frontier of advanced responses to health challenges and sectoral policy targets. Cell‐based therapy holds great promise for tendon disorder resolution. To verify the role of stepwise trans‐differentiation of amniotic epithelial stem cells (AECs) in tendon regeneration, in the present research three different AEC subsets displaying an epithelial (eAECs), mesenchymal (mAECs), and tendon‐like (tdAECs) phenotype were allotransplanted in a validated experimental sheep Achilles tendon injury model. Tissue healing was analyzed adopting a comparative approach at two early healing endpoints (14 and 28 days). All three subsets of transplanted cells were able to accelerate regeneration: mAECs with a lesser extent than eAECs and tdAECs as indicated in the summary of the total histological scores (TSH), where at day 28 eAECs and tdAECs had better significant scores with respect to mAEC‐treated tendons (p < 0.0001). In addition, the immunomodulatory response at day 14 showed in eAEC‐transplanted tendons an upregulation of pro‐regenerative M2 macrophages with respect to mAECs and tdAECs (p < 0.0001). In addition, in all allotransplanted tendons there was a favorable IL10/IL12 compared to CTR (p < 0.001). The eAECs and tdAECs displayed two different underlying regenerative mechanisms in the tendon. The eAECs positively influenced regeneration mainly through their greater ability to convey in the host tissue the shift from pro‐inflammatory to pro‐regenerative responses, leading to an ordered extracellular matrix (ECM) deposition and blood vessel remodeling. On the other hand, the transplantation of tdAECs acted mainly on the proliferative phase by impacting the density of ECM and by supporting a prompt recovery, inducing a low cellularity and angle alignment of the host cell compartment. These results support the idea that AECs lay the groundwork for production of different cell phenotypes that can orient tendon regeneration through a crosstalk with the host tissue. In particular, the obtained evidence suggests that eAECs are a practicable and efficient strategy for the treatment of acute tendinopathies, thus reinforcing the grounds to move their use towards clinical practice

Le scene di battaglia dell'Iliade

The review (Oliver Hellmann, Die Schlachtszenen der Ilias: das Bild des Dichters vom Kampf in der Heroenzeit, Franz Steiner Verlag, Stuttgart 2000) focuses on Hellmann?s method in the analysis of the connection between war and heroic society and in the study of the conditions of the recruitment and fighting (formation and organization of troops, tactics, individual duel and mass-attack), although the author admits that Homer?s Iliad is an artistic work and so he gives up the idea of offering a precise and consistent historical description on the grounds of Homeric poetry

La retorica dimenticata : nuove ricerche sul vocabolario greco

La ricerca, nata da un progetto di revisione e integrazione del lessico retorico di J.Ch.G. Ernesti, Lexicon Technologiae Graecorum Rhetoricae, Leipzig 1797 (rist. Hildesheim 1962) segnala ed esamina complessivamente trentatre voci che, pur caratterizzate da una marcata valenza tecnico- retorica, risultano assenti dai principali repertori lessicografici moderni. La selezione di questi vocaboli è stata effettuata attraverso un lavoro articolato in tre distinte operazioni: 1) esame degli indici in appendice alle edizioni dei manuali retorici antichi e dei corpora scoliografic; 2) lettura diretta dei manuali stessi; 3) verifica dell'effettiva rilevanza retorica dei vocaboli così individuati. Al fine di garantire la massima coerenza alla selezione dei materiali, è stata seguita la norma di considerare rilevanti soltanto quelle voci per le quali si disponesse di almeno due attestazioni retoricamente significative, e preferibilmente in autori diversi. Per praticità di esposizione e di consultazione, inoltre, si è reputato opportuno suddividere i termini selezionati in due distinte sezioni: nella prima sono stati presi in considerazione i termini attestati come denominazioni di figure o procedimenti stilistici; nella seconda sono stati invece inclusi termini originari del lessico grammaticale successivamente specializzatisi in accezioni tecnico-retoriche. È stato così possibile individuare nuove figure retoriche, come la "figura dell'indivisione", quella del "ritorno al soggetto" dopo una digressione, o ancora quelle dell'"intreccio" e del "movimento a ritroso", solo per menzionare alcuni esempi particolarmente significativi. A ciascuna voce è stato dedicato un capitolo specifico, composto dei seguenti elementi: 1) quadro sintetico dell'evoluzione semantica; 2) analisi delle attestazioni retoriche e/o retorico-grammaticali; 3) definizione dell'esatto significato retorico. Pur rinunciando a qualunque pretesa di esaustività, il presente studio si prefigge dunque il duplice obiettivo di denunciare i limiti dei repertori lessicografici moderni e di ampliare i confini della dottrina retorica antica, recuperando materiale dimenticato e aprendo, se possibile, nuove piste di ricerca

Teaching Performative Scale (TPS): uno strumento per rilevare la performatività del docente

This contribution is part of the theoretical framework that interprets theatre, the performance art par excellence, as teaching and teaching as theatre (Rivoltella, 2012; 2017; 2021). The assumption is not metaphorical, but refers to the tradition that sees the teacher’s performance as an integration of body and action (Rossi, 2011) allowing the didactic event to be co-constructed thanks to the students. The aim of the work will be to present the performative paradigm in the context of teaching action, the consequent construction of a structured questionnaire (Teaching Performative Scale) investigating the reference competence and representations in the performative teaching situation. We present the reference theory, the construction of the instrument and its validation process of construct (Cronbach, 1971; Sartori - Pasini, 2007) and content (Escobar Pérez - Cuervo Martinez, 2008)