Calcium/Cobalt Alginate Beads as Functional Scaffolds for Cartilage Tissue Engineering

Articular cartilage is a highly organized tissue with complex biomechanical properties. However, injuries to the cartilage usually lead to numerous health concerns and often culminate in disabling symptoms, due to the poor intrinsic capacity of this tissue for self-healing. Although various approaches are proposed for the regeneration of cartilage, its repair still represents an enormous challenge for orthopedic surgeons. The field of tissue engineering currently offers some of the most promising strategies for cartilage restoration, in which assorted biomaterials and cell-based therapies are combined to develop new therapeutic regimens for tissue replacement. The current study describes the in vitro behavior of human adipose-derived mesenchymal stem cells (hADSCs) encapsulated within calcium/cobalt (Ca/Co) alginate beads. These novel chondrogenesis-promoting scaffolds take advantage of the synergy between the alginate matrix and Co+2 ions, without employing costly growth factors (e.g., transforming growth factor betas (TGF-βs) or bone morphogenetic proteins (BMPs)) to direct hADSC differentiation into cartilage-producing chondrocytes

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

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

Synovium-derived stromal cell-induced osteoclastogenesis: a potential osteoarthritis trigger

none7noPurpose: To shed light on the idea that mesenchymal stem/stromal cells (MSCs) recruited in synovium (SM) (i.e. Synovium-Derived Stromal Cells, SDSCs) could be involved in Osteoarthritis (OA) pathophysiology. Attention was also paid to a further stromal cell type with a peculiar ultrastructure called telocytes (TCs), whose role is far from clarified. Methods: In the present in vitro study, we compared SDSCs isolated from healthy and OA subjects in terms of phenotype, morphology and differentiation potential as well as in their capability to activate normal Peripheral Blood Mononuclear Cells (PBMCs). Histological, immunohistochemical and ultrastructural analyses were integrated by qRT-PCR and functional resorbing assays. Results: Our data demonstrated that both SDSC populations stimulated the formation of osteoclasts from PBMCs: the osteoclast-like cells generated by healthy-SDSCs via transwell co-cultures were inactive, while OA-derived SDSCs have a much greater effectiveness. Moreover, the presence of TCs was more evident in cultures obtained from OA subjects and suggests a possible involvement of these cells in OA. Conclusions: Osteoclastogenic differentiation capability of PBMCs from OA subjects, also induced by B synoviocytes has been already documented. Here we hypothesized that SDSCs, generally considered for their regenerative potential in cartilage lesions, have also a role in the onset/maintenance of OA. Clinical relevance: Our observations may represent an interesting opportunity for the development of a holistic approach for OA treatment, that considers the multifaceted capability of MSCs in relation to the environment.embargoed_20210517Dicarlo, Manuela; Teti, Gabriella; Cerqueni, Giorgia; Iezzi, Iolanda; Gigante, Antonio; Falconi, Mirella; Mattioli-Belmonte, MonicaDicarlo, Manuela; Teti, Gabriella; Cerqueni, Giorgia; Iezzi, Iolanda; Gigante, Antonio; Falconi, Mirella; Mattioli-Belmonte, Monic

Biofabrication of bundles of poly(lactic acid)-collagen blends mimicking the fascicles of the human Achille tendon

Electrospinning is a promising technique for the production of scaffolds aimed at the regeneration of soft tissues. The aim of this work was to develop electrospun bundles mimicking the architecture and mechanical properties of the fascicles of the human Achille tendon. Two different blends of poly(L-lactic acid) (PLLA) and collagen (Coll) were tested, PLLA/Coll-75/25 and PLLA/Coll-50/50, and compared with bundles of pure PLLA. First, a complete physico-chemical characterization was performed on non-woven mats made of randomly arranged fibers. The presence of collagen in the fibers was assessed by thermogravimetric analysis, differential scanning calorimetry and water contact angle measurements. The collagen release in phosphate buffer solution (PBS) was evaluated for 14 days: results showed that collagen loss was about 50% for PLLA/Coll-75/25 and 70% for PLLA/Coll-50/50. In the bundles, the individual fibers had a diameter of 0.48 ±0.14 μm (PLLA), 0.31 ±0.09 μm (PLLA/Coll-75/25), 0.33 ±0.08 μm (PLLA/Coll-50/50), whereas bundle diameter was in the range 300-500 μm for all samples. Monotonic tensile tests were performed to measure the mechanical properties of PLLA bundles (as-spun) and of PLLA/Coll-75/25 and PLLA/Coll-50/50 bundles (as-spun, and after 48 h, 7 days and 14 days in PBS). The most promising material was the PLLA/Coll-75/25 blend with a Young modulus of 98.6 ±12.4 MPa (as-spun) and 205.1 ±73.0 MPa (after 14 days in PBS). Its failure stress was 14.2 ±0.7 MPa (as-spun) and 6.8 ±0.6 MPa (after 14 days in PBS). Pure PLLA withstood slightly lower stress than the PLLA/Coll-75/25 while PLLA/Coll-50/50 had a brittle behavior. Human-derived tenocytes were used for cellular tests. A good cell adhesion and viability after 14 day culture was observed. This study has therefore demonstrated the feasibility of fabricating electrospun bundles with multiscale structure and mechanical properties similar to the human tendon

Assessment of the structural and functional characteristics of human mesenchymal stem cells associated with a prolonged exposure of morphine

The discovery of the expression of opioid receptors in the skin and their role in orchestrating the process of tissue repair gave rise to questions regarding the potential effects of clinical morphine treatment in wound healing. Although short term treatment was reported to improve tissue regeneration, in vivo chronic administration was associated to an impairment of the physiological healing process and systemic fibrosis. Human mesenchymal stem cells (hMSCs) play a fundamental role in tissue regeneration. In this regard, acute morphine exposition was recently reported to impact negatively on the functional characteristics of hMSCs, but little is currently known about its long-term effects. To determine how a prolonged treatment could impair their functional characteristics, we exposed hMSCs to increasing morphine concentrations respectively for nine and eighteen days, evaluating in particular the fibrogenic potential exerted by the long-term exposition. Our results showed a time dependent cell viability decline, and conditions compatible with a cellular senescent state. Ultrastructural and protein expression analysis were indicative of increased autophagy, suggesting a relation to a detoxification activity. In addition, the enhanced transcription observed for the genes involved in the synthesis and regulation of type I collagen suggested the possibility that a prolonged morphine treatment might exert its fibrotic potential risk, even involving the hMSCs

A synergic effect of alginate and hypoxia-inducing ions on chondrogenic differentiation in adipose derived mesenchymal stem cells

Cartilage is a highly organized tissue with complex biomechanical properties, but since it has a poor intrinsic capacity of self-healing, injuries at this site usually lead to several problems, often ending in disabling symptoms. Although, different approach- es have been proposed, even now cartilage repair represents a great challenge for orthopaedic surgeons (1, 2). One of the promising approach is given from tissue engineering, employing the combination of biomaterials and cell therapy to develop new therapeutic strategies. In this paper, we describe the behaviour of human adipose derived mesenchymal stem cells encapsulated into Ca/Co alginate beads as potential chondrogenic inducing biomaterial tacking advance on the synergy between alginate matrix and Co+2 ions without employing other expensive growth factors such as TGFbs or BMPs. Cells were cultured up to 3 weeks into alginate beads at different Ca/Co ratio, Calcein/Ethidium assay was performed to evaluate cell viability, light, and transmis- sion electron microscopy were carried out to check the cells behaviour. The expression of chondrogenic markers such as sox9, collagen type II, and versican was investigated by Real Time PCR. The expression of hif1mRNA was investigated to check the capability of Co+2 ions to induce a chemical hypoxia. Results showed an high cell viability at high Ca/Co ratio value of alginate beads. Real Time PCR data reveal a different cells behaviour on chondrogenic marker expression. In conclusion, the synergic effect of alginate and Co+2 ions can represent a valid strategy for chondrogenic differentiation of stem cells

A synergic effect of alginate and hypoxia-inducing ions on chondrogenic differentiation in adipose derived mesenchymal stem cells

Cartilage is a highly organized tissue with complex biomechanical properties, but since it has a poor intrinsic capacity of self-healing, injuries at this site usually lead to several problems, often ending in disabling symptoms. Although, different approach- es have been proposed, even now cartilage repair represents a great challenge for orthopaedic surgeons (1, 2). One of the promising approach is given from tissue engineering, employing the combination of biomaterials and cell therapy to develop new therapeutic strategies. In this paper, we describe the behaviour of human adipose derived mesenchymal stem cells encapsulated into Ca/Co alginate beads as potential chondrogenic inducing biomaterial tacking advance on the synergy between alginate matrix and Co+2 ions without employing other expensive growth factors such as TGFbs or BMPs. Cells were cultured up to 3 weeks into alginate beads at different Ca/Co ratio, Calcein/Ethidium assay was performed to evaluate cell viability, light, and transmis- sion electron microscopy were carried out to check the cells behaviour. The expression of chondrogenic markers such as sox9, collagen type II, and versican was investigated by Real Time PCR. The expression of hif1mRNA was investigated to check the capability of Co+2 ions to induce a chemical hypoxia. Results showed an high cell viability at high Ca/Co ratio value of alginate beads. Real Time PCR data reveal a different cells behaviour on chondrogenic marker expression. In conclusion, the synergic effect of alginate and Co+2 ions can represent a valid strategy for chondrogenic differentiation of stem cells

3D polysaccharide based hydrogel for bone tissue engineering

Hydrogels have attracted considerable attention in biomedical engineering applications due to their many favorable biomimetic properties. Hydrogels based on proteins or carbohydrates can also function as effective extracellular matrices to direct cellular behavior. Recently, polysaccharide based hydrogels have become particularly interesting as matrices for the repair and regeneration of a wide variety of tissues and organs. The incorporation of inorganic minerals as hydroxyapatite nanoparticles can modulate the performance of the hydrogel with potential applications for bone tissue engineering. The aim of this study was to verify the biological potential of a new carboxymethyl cellulose—hydroxyapatite hybrid hydrogel in bone tissue regeneration. Mesenchymal stem cells were seeded on hydrogel scaffold, in presence and absence of hydroxyapatite, for 7, 14 and 21 days. Cell viability assay and morphological analysis were carried out to evaluate biocompatibility and cell adhesion of the materials. Real Time PCR for genes involved in tissue regeneration was carried out to assay the influence of the scaffold in cell differentiation. Results showed a high cell viability and biocompatibility of the tested material, confirmed by morphological analysis. The evaluation of osteoblast markers demonstrated the osteogenic induction of the 3D material enriched with hydroxyapatite in the production of mineralized extracellular matrix compared to the carboxymethyl cellulose based material. In conclusion, our data show that carboxymethyl cellulose—hydroxyapatite hybrid hydrogel may have great potential in bone tissue engineering applications