Bio-Medical Materials and Engineering - Volume 24, issue s1
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Bio-Medical Materials and Engineering is to promote the welfare of humans and to help them keep healthy. This international journal is an interdisciplinary journal that publishes original research papers, review articles and brief notes on materials and engineering for biological and medical systems.
Articles in this peer-reviewed journal cover a wide range of topics, including, but not limited to: Engineering as applied to improving diagnosis, therapy, and prevention of disease and injury, and better substitutes for damaged or disabled human organs; Studies of biomaterial interactions with the human body, bio-compatibility, interfacial and interaction problems; Biomechanical behavior under biological and/or medical conditions; Mechanical and biological properties of membrane biomaterials; Cellular and tissue engineering, physiological, biophysical, biochemical bioengineering aspects; Implant failure fields and degradation of implants. Biomimetics engineering and materials including system analysis as supporter for aged people and as rehabilitation; Bioengineering and materials technology as applied to the decontamination against environmental problems; Biosensors, bioreactors, bioprocess instrumentation and control system; Application to food engineering; Standardization problems on biomaterials and related products; Assessment of reliability and safety of biomedical materials and man-machine systems; and Product liability of biomaterials and related products.
Abstract: Osteoarthritis (OA) is a whole-joint disease characterized by cartilage degradation and mineralization associated with chondrocyte phenotype changes, subchondral bone sclerosis and mild synovial inflammation. The extracellular levels of inorganic phosphate (ePi) and pyrophosphate (ePPi) are major regulators of the mineralization process but also play a role in the maintenance of the differentiated chondrocyte phenotype. Four membrane proteins control the balance between ePi and ePPi: the transporters ANK (exporting PPi outside the cells) and PiT-1 (importing ePi into the cells), and the enzymes PC-1 (generating ePPi from nucleotides) and Tissue Non-specific Alkaline Phosphatase (TNAP, hydrolyzing ePPi into ePi). In the present…work, we investigated the ability of specific microRNAs (miR) to modulate activity and level of the mRNA coding for the regulatory proteins of the ePi/ePPi balance in chondrocytes. The 4 following microRNAs, let7e, miR-9, miR-188 and miR-219, were selected by bioinformatics for their ability to putatively target the mRNA 3′UTRs of these regulators. In IL-1β-stimulated human chondrocytes, chosen as a model of differentiated phenotype loss implicating the PPi transporter ANK, miR-9, miR-188 and let7e levels increased. However, luciferase reporter assays and transient miR overexpression in the ATDC5 chondrogenic cell line only support that miR-9 was a negative post-transcriptional regulator of PC-1, Pit-1 and TNAP mRNAs. This suggests that miR-9 could contribute to the acquirement of an altered chondrocyte phenotype by disrupting the ePi/ePPi balance.
Abstract: The role of body weight in the pathogenesis of osteoarthritis (OA) – previously considered the sole factor in the association between obesity and OA – is being re-evaluated as the contribution of adiposity to the cartilage degenerative process becomes clearer. The current study has been undertaken to better understand the role of adipose-derived proteins, namely adipokines, in OA. For this purpose, we investigated in patients with OA the relationships between the joint levels of leptin, adiponectin and resistin and those of factors involved in inflammation and cartilage maintenance. The sandwich enzyme-linked immunosorbent assays were used to determine in the synovial…fluid (SF) from 35 OA patients, the concentrations of adipokines, interleukin-6 (IL-6) and transforming growth factor-β (TGF-β). The soluble form of leptin receptor (sOb-R) was also examined to evaluate the biological active free form of leptin. Correlation analysis indicate that IL-6 levels are positively related to the levels of resistin and adiponectin. Surprisingly, the free form of leptin, but not the total leptin, is negatively associated with IL-6. Beside, adiponectin is the single adipokine that is correlated with TGF-β. Interestingly, a sexual dimorphism is observed in the study as correlations between adipokines and IL-6 or TGF-β are found only with female OA patients. Taken together, these findings suggest that only adiponectin may contribute to the metabolic changes associated with OA. The three adipokines may also be involved in inflammation, but with opposite effects. Both resistin and adiponectin may exhibit pro-inflammatory activity while the free form of leptin may down-regulate the inflammation.
Abstract: BACKGROUND: Although a large number of studies have documented the interaction of mesenchymal stem cells (MSCs) with cells of both the innate and adaptive immune systems, not much is known about how bacteria interact with MSCs and how this might influence MSCs behavior. In this study, we investigated the impact of Staphylococcus aureus (S. aureus), on viability and cytokines' production of human Wharton's jelly-MSCs (WJ-MSCs). OBJECTIVE: To investigate if WJ-MSCs: (1) internalize S. aureus; (2) are able to survive and (3) release immunomodulatory mediators after interaction with S. aureus. METHODS: WJ-MSCs were exposed to S. aureus at a…multiplicity of infection (MOI) of 10:1 or 30:1 for different designed times. After interaction, intracellular bacteria were quantified as well as MSCs viability. Expression and cytokine-secretion were assessed using quantitative real-time PCR and ELISA. RESULTS: We found that the challenge of WJ-MSCs with S. aureus resulted in increased internalization of S. aureus in a time-dependent manner until six hours post-infection at either MOI of 10:1 and 30:1 and in increased expression of IL-6 mRNA and secretion of TNF-α at six hours and nine hours post-infection (p<0.05). CONCLUSIONS: These results indicate that WJ-MSCs are able to internalize S. aureus and reveal a potential important function of these cells in the immune response.
Keywords: Human Wharton's jelly stem cells (WJ-MSCs), Staphylococcus aureus (S. aureus), inflammation, internalization
Abstract: BACKGROUND: During aging or various diseases, pathologic mineralization may occur in joints or in the vascular wall. This is due to the deposition of phosphate (Pi)-containing crystals into the extracellular matrix of articular chondrocytes or vascular smooth muscle cells. The mineralization ability of chondrocytes and smooth muscle cells of other tissue has not been investigated. OBJECTIVE: In this context, our work seeks to study the response induced by Pi on cartilage and smooth muscle cells from tracheal origin. METHODS: We have established a dissection procedure to harvest and isolate chondrocyte and smooth muscle cells from adult mouse trachea.…Both cell types were then exposed to different concentrations of Pi (1, 3 or 5 mM) up to 14 days. Mineralization was evaluated by alizarin red staining, which identifies calcium deposition. The expression of genes characterizing the phenotypic identity of the cells and involved in the mineralization process was assessed by RT-qPCR. RESULTS: Treatment of tracheal chondrocytes and smooth muscle cells with increasing concentrations of Pi (3 and 5 mM) induced mineralization as revealed by positive alizarin red staining as early as 7 days of culture. Moreover, gene expression analysis revealed profound phenotypic changes in both cell types and suggested they mineralize through TNAP-independent or -dependent mechanisms, respectively. CONCLUSIONS: Our data indicate that, comparably to articular chondrocytes or vascular smooth muscles, chondrocyte and smooth muscle cells from the trachea are prone to mineralize under high-phosphate conditions.
Abstract: While mesenchymal stem cells represent an interesting cell source for regenerative medicine, several points have to be investigated to improve their use in clinical, and in particular in the elderly population. This work studied the proliferation capacity of mesenchymal stem cells isolated from human bone marrow in function of donor's age. Doubling time after in vitro culture, clonogenicity and phenotype were analyzed in 17 samples ranging from 3 to 85 years old (mean 47±27). Results showed an increase in the doubling time for cell coming from old donor compared to cells coming from young ones. This was accompanied by a…decrease in clonogenicity while no changes were observe in cell phenotype. In conclusion, this study showed an effect of donor's age on the proliferation capacity of mesenchymal stem cells isolated from bone marrow that was correlated to a decrease in clonogenicity. The comprehension of molecular mechanism involved in this process could help to improve the clinical application of mesenchymal stem cells.
Keywords: Mesenchymal stem cells, bone marrow, aging, proliferation, clonogenicity
Abstract: Stem cells are the most powerful candidate for the treatment of various diseases. Suitable stem cell source should be harvested with minimal invasive procedure, found in great quantity, and transplanted with no risk of immune response and tumor formation. Fetal derived stem cells have been introduced as an excellent alternative to adult and embryonic stem cells use, but unfortunately, their degree of “stemness” and molecular characterization is still unclear. Several studies have been performed deciphering whether fetal stem cells meet the needs of regenerative medicine. We believe that a transcriptomic screening of Wharton's jelly stem cells will bring insights on…cell population features.
Keywords: PCR array, human Wharton's jelly stem cells, regenerative medicine
Abstract: BACKGROUND: To favor regeneration following critical bone defect, a combination of autologous bone graft and biomaterials is currently used. Major drawbacks of such techniques remain the availability of the autologous material and the second surgical site, inducing pain and morbidity. OBJECTIVE: Our aim was to investigate the biocompatibility in vitro of three dimensions hybrid biodegradable scaffolds combining osteoconductive properties of hydroxyapatite and anti-inflammatory properties of chitosan. METHODS: Hybrid scaffolds were characterized by microscopic observations, equilibrium swelling ratio and overtime weight loss measurements. In vitro studies were performed using primary human bone cells cultured for 7, 14 and 21…days. Cell viability, proliferation, morphology and differentiation through alkaline phosphatase (ALP) activity measurement were assessed. RESULTS: Characterization of our scaffolds demonstrated porous, hydrophilic and biodegradable characteristics. In vitro studies showed that these scaffolds have induced slight decrease in cell death and proliferation comparing to the culture plastic substrate control condition, as well as increased short term osteoinductive properties. CONCLUSIONS: In this study, we have provided evidence that our hybrid hydroxyapatite/chitosan scaffolds could be suitable for bone filling.
Keywords: Hydroxyapatite, three dimensions hybrid scaffold, human primary bone cells
Abstract: BACKGROUND: Age is the most important risk factor for primary osteoarthritis (OA). Members of the TGF-β superfamily play a crucial role in chondrocyte differentiation and maintenance of healthy articular cartilage. OBJECTIVE: We have investigated whether age-related changes in TGF-β superfamily signaling components play a role in the relationship between OA-related cartilage degradation and aging. MATERIAL AND METHODS: The relationship between age, OA and TGF-β superfamily signaling was studied using murine experimental OA models, aging mice, bovine articular cartilage and human OA cartilage. The effects of TGF-β on cartilage homeostasis was studied with immunohistochemistry, Q-RT-PCR and signaling pathway analysis…with Western blotting and the application of specific TGF-β inhibitors. RESULTS: We have found that TGF-β loses its protective effects in old cartilage. Moreover, we found that on chondrocytes, TGF-β not only signals via the canonical type I receptor ALK5 (TGFBR1) but also via the ALK1 (ACVRL1) receptor. Remarkably, signaling via ALK5 (Smad2/3 route) results in protective while ALK1 signaling (Smad1/5/8 route) results in deleterious responses in articular chondrocytes. In cartilage of aging mice it was detected that the ALK1/ALK5 ratio is significantly increased, favoring TGF-β signaling via the Smad1/5/8 route, inducing changes in chondrocyte differentiation and matrix metalloproteinase-13 (MMP-13) expression. Moreover, human OA cartilage showed a significant correlation between ALK1 and MMP-13 expression. Since in mice aging and OA in often goes hand in hand, we also analyzed age-related expression of TGF-β superfamily related signaling molecules in healthy bovine cartilage in an age range from 6 months to 14 years. In this cohort of aging cartilage, we found that mainly signaling receptors determining the Smad2/3 pathway were decreased with age while Smad1/5/8-related signaling molecules did not alter, confirming our findings in aging mice. CONCLUSIONS: Old cartilage appears to be less protected by TGF-β and shows significant alterations in TGF-β signaling pathways. Loss of the protective Smad2/3 pathway during aging can provide an explanation for the relationship between OA and aging.
Abstract: BACKGROUND: Rheumatoid arthritis is characterized by synovial hyperplasia, inflammatory infiltration, cartilage destruction and juxta-articular as well as generalized bone demineralization. Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily which behave as ligand-activated transcription factors in response to endogenous fatty acids and eicosanoids or isotype selective synthetic compounds as fibrates and thiazolidinediones. Beyond their key role in lipid metabolism, increased evidence has shown a role of the three isotypes in inflammatory modulation. We and others demonstrated previously that PPAR-gamma agonists reduced the severity of experimental polyarthritis and the overall inflammatory-induced bone loss. OBJECTIVE: To compare the…anti-arthritic potencies of a PPAR-alpha agonist (fenofibrate, a lipid lowering drug) and a PPAR-gamma agonist (pioglitazone, formerly used as an antidiabetic drug) in rat adjuvant-induced arthritis. METHODS: Male Lewis rats were sensitized by an intra-dermal injection of 1 mg complete Freund's adjuvant at the basis of the tail and were treated orally for 21 days with fenofibrate 100 mg/kg/day (FENO) or pioglitazone 30 mg/kg/day (PIO), or with vehicle only. Arthritis severity was evaluated by clinical observations (oedema, clinical score, body weight). Global and femoral bone mineral density (BMD), femoral bone mineral content (BMC) were measured by dual-energy X-ray absorptiometry (DEXA) before sensitization and at day 20. Synovial mRNA levels of IL-1beta and IL-6 were determined by real-time RT-PCR. RESULTS: Administration of fenofibrate (100mg/kg/d) and pioglitazone (30 mg/kg/d) significantly reduced hindpaw oedema and arthritis score. Treatment with fenofibrate exerted a better effect on clinical scoring. DEXA analysis revealed that pioglitazone and fenofibrate treatment to a greater extent, reduced inflammatory-bone loss and increased BMD versus vehicle-treated rats. Finally, we demonstrated that both agonists decreased synovial expression of IL-1beta and IL-6. CONCLUSION: Pioglitazone and fenofibrate decreased arthritis severity in adjuvant-induced arthritis. Both agonists partially protected animals from inflammatory induced-bone loss.
Keywords: Adjuvant arthritis, PPARs, pioglitazone, fenofibrate, bone