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Osteosarcoma (OS) is the most common primary malignant tumor of bone, which preferentially develops lung metastasis. Although standard chemotherapy has significantly improved long-term survival over the past few decades, the outcome for patients with metastatic or recurrent OS remains dramatically poor. Novel therapies are therefore required to slow progression and eradicate the disease. Furthermore, to better understand the cellular and molecular mechanisms responsible for OS onset and progression, the development of novel predictive culture systems resembling the native three-dimensional (3D) tumor microenvironment are mandatory. 'Tumor engineering' approaches radically changed the previous scenario, through the development of advanced and alternative 3D cell culture in vitro models able to tightly mimic the in vivo tumor microenvironment. In this review, we will summarize the state of the art in this novel area, illustrating the different methods and techniques employed to realize 3D OS cell culture models and we report the achieved results, which highlight the efficacy of these models in reproducing the tumor milieu. Although data need to be further validated, the scientific studies reviewed here are certainly promising and give new insights into the clinical practice. [ABSTRACT FROM AUTHOR]

Background: Osteoarthritis (OA) is the final result of progressive alterations to articular cartilage structure, composition and cellularity, followed by an increase in the concentration of pro-inflammatory cytokines in joint synovial fluid. Even though the effect of pulsed electromagnetic field (PEMF) stimulation in counteracting OA progression and inflammation is of increasing interest, because of its anabolic and anti-inflammatory properties, the present study aimed to improve the knowledge on cartilage extracellular matrix (ECM) and chondrocyte changes related to the exposure of PEMF, from a histological and histomorphometric point of view.Methods: An in vitro OA model was realized, culturing bovine cartilage explants with a high dose of interleukin 1β (IL1β, 50 ng/ml) at different experimental times (24 h, and 7 and 21 days). The effects of PEMFs (75 Hz, 1.5 mT) were evaluated in cartilage explants treated with IL1β or not (control), in terms of cartilage structure, cellularity and proteoglycans, glycosaminoglycans, collagen II and transforming growth factor β1 synthesis by using histology, histomorphometry and immunohistochemistry.Results: Making a comparison with control cartilage, IL1β-treated explants showed a decrease in cartilage matrix, structure and cellularity parameters. PEMFs were able to counteract the progression of OA acting on both cartilage cellularity and ECM in cartilage previously treated with IL1β. Normal distribution (Kolmogroc-Smirnov test) and homoscedasticity (Levene test) of data were verified, then, the non-parametric Kruskal Wallis test followed by Mann-Whiteny U test for pairwise comparisons were performed. The p-value was adjusted according to the Dunn-Sidak correction.Conclusions: These results, obtained by culturing and treating cartilage explants from two different joints, confirmed that PEMF stimulation can be used as adjuvant therapy to preserve cartilage from detrimental effects of high inflammatory cytokine levels during OA. [ABSTRACT FROM AUTHOR]

Background: The study aimed to evaluate the combined effect of Pulsed Electromagnetic Field (PEMF) biophysical stimulation and bone marrow concentrate (BMC) in osteochondral defect healing in comparison to the treatment with scaffold alone. Methods: An osteochondral lesion of both knees was performed in ten rabbits. One was treated with a collagen scaffold alone and the other with scaffold seeded with BMC. Half of the animals were stimulated by PEMFs (75 Hz, 1.5 mT, 4 h/day) and at 40 d, macroscopic, histological and histomorphometric analyses were performed to evaluate osteochondral defect regeneration. Results: Regarding cartilage, the addition of BMC to the scaffold improved cell parameters and the PEMF stimulation improved both cell and matrix parameters compared with scaffold alone. The combination of BMC and PEMFs further improved osteochondral regeneration: there was an improvement in macroscopic, cartilage cellularity and matrix parameters and a reduction in the percentage of cartilage under the tidemark. Epiphyseal bone healing improved in all the osteochondral defects regardless of treatment, although PEMFs alone did not significantly improve the reconstruction of subchondral bone in comparison to treatment with scaffold alone. Conclusions: Results show that BMC and PEMFs might have a separate effect on osteochondral regeneration, but it seems that they have a greater effect when used together. Biophysical stimulation is a non-invasive therapy, free from side effects and should be started soon after BMC transplantation to increase the quality of the regenerated tissue. However, because this is the first explorative study on the combination of a biological and a biophysical treatment for osteochondral regeneration, future preclinical and clinical research should be focused on this topic to explore mechanisms of action and the correct clinical translation. [ABSTRACT FROM AUTHOR]

Background: The study aimed to evaluate the combined effect of Pulsed Electromagnetic Field (PEMF) biophysical stimulation and bone marrow concentrate (BMC) in osteochondral defect healing in comparison to the treatment with scaffold alone. Methods: An osteochondral lesion of both knees was performed in ten rabbits. One was treated with a collagen scaffold alone and the other with scaffold seeded with BMC. Half of the animals were stimulated by PEMFs (75Hz,1.5m T,4h/day) and at 40 d, macroscopic, histological and histomorphometric analyses were performed to evaluate osteochondral defect regeneration. Results: Regarding cartilage, the addition of BMC to the scaffold improved cell parameters and the PEMF stimulation improved both cell and matrix parameters compared with scaffold alone. The combination of BMC and PEMFs further improved osteochondral regeneration: there was an improvement in macroscopic, cartilage cellularity and matrix parameters and a reduction in the percentage of cartilage under the tidemark. Epiphyseal bone healing improved in all the osteochondral defects regardless of treatment, although PEMFs alone did not significantly improve the reconstruction of subchondral bone in comparison to treatment with scaffold alone. Conclusions: Results show that BMC and PEMFs might have a separate effect on osteochondral regeneration, but it seems that they have a greater effect when used together. Biophysical stimulation is a non-invasive therapy, free from side effects and should be started soon after BMC transplantation to increase the quality of the regenerated tissue. However, because this is the first explorative study on the combination of a biological and a biophysical treatment for osteochondral regeneration, future preclinical and clinical research should be focused on this topic to explore mechanisms of action and the correct clinical translation. [ABSTRACT FROM AUTHOR]

Background: Metal-on-metal hip resurfacing arthroplasty (HR) has been gaining popularity especially for young and active patients. Although different series report good mid-term results, the long-term outcome and failure mechanisms are still concerning. In this consecutive revision case series, 9 retrieved specimens of a failed Birmingham Hip Resurfacing (BHR) were divided according to the time to fracture: 3 specimens failed at less than 6 months (Group 1), 3 failed between 6 months and 3 years (Group 2) and 3 failed later than 3 years (Group 3). The objective of the study was to examine by a specific quantitative histomorphometry and microtomography (micro-CT) method the characteristics of bone quality and its microarchitecture in retrieved metal-on-metal HR. Methods: A series of 948 BHR were performed between 2001 and 2009. Among these implants 10 failures occurred and nine of these underwent revision surgery and were examined by histomorphometry and micro-CT. Results: Histomorphometry showed a significant increase in trabecular separation (Tb.Sp) in Group 3 in comparison with Group 1 (113%, p < 0.05). In the top region, micro-CT showed that Groups 2 and 3 presented significant lower bone volume (Group 2: 61%, p < 0.005; Group 3: 1%, p < 0.05), trabecular number (Group 2: 53%, p < 0.005; Group 3: 40%, p < 0.05), and higher Tb.Sp (Group: 71%,p < 0.05) when compared to Group 1. Additionally, histomorphometry showed that the top regions in Group 1 had a significantly lower mean percentage of empty osteocyte lacunae than the top regions in both Group 2 and 3 (p<0.05). Conclusions: This study showed that the morphometric parameters considered are crucial for a good understanding of mechanical properties of HR and may be of significant importance in the pathogenesis of HR failure particularly in the development of late fractures. [ABSTRACT FROM AUTHOR]

Background: Although progress has been made in the treatment of articular cartilage lesions, they are still a major challenge because current techniques do not provide satisfactory long-term outcomes. Tissue engineering and the use of functional biomaterials might be an alternative regenerative strategy and fulfill clinical needs. Decellularized extracellular matrices have generated interest as functional biologic scaffolds, but there are few studies on cartilage regeneration. The aim of this study was to evaluate in vitro the biological influence of a newly developed decellularized human dermal extracellular matrix on two human primary cultures. Methods: Normal human articular chondrocytes (NHAC-kn) and human mesenchymal stromal cells (hMSC) from healthy donors were seeded in polystyrene wells as controls (CTR), and on decellularized human dermis batches (HDM_derm) for 7 and 14 days. Cellular proliferation and differentiation, and anabolic and catabolic synthetic activity were quantified at each experimental time. Histology and scanning electron microscopy were used to evaluate morphology and ultrastructure. Results: Both cell cultures had a similar proliferation rate that increased significantly (p < 0.0005) at 14 days. In comparison with CTR, at 14 days NHAC-kn enhanced procollagen type II (CPII, p < 0.05) and aggrecan synthesis (p < 0.0005), whereas hMSC significantly enhanced aggrecan synthesis (p < 0.0005) and transforming growth factor-beta1 release (TGF-β1, p < 0.0005) at both experimental times. Neither inflammatory stimulus nor catabolic activity induction was observed. By comparing data of the two primary cells, NHAC-kn synthesized significantly more CPII than did hMSC at both experimental times (p < 0.005), whereas hMSC synthesized more aggrecan at 7 days (p < 0.005) and TGF-β1 at both experimental times than did NHAC-kn (p < 0.005). Conclusions: The results obtained showed that in in vitro conditions HDM_derm behaves as a suitable scaffold for the growth of both well-differentiated chondrocytes and undifferentiated mesenchymal cells, thus ensuring a biocompatible and bioactive substrate. Further studies are mandatory to test the use of HDM_derm with tissue engineering to assess its therapeutic and functional effectiveness in cartilage regeneration. [ABSTRACT FROM AUTHOR]

Background: Different conditions may alter tendon characteristics. Clinical evidence suggests that tendon injuries are more frequent in athletes that change type, intensity and duration of training. Aim of the study was the assessment of training and especially detraining on the patellar tendon (PT) and its enthesis. Methods: 27 male adult Sprague-Dawley rats were divided into 3 groups: 20 rats were trained on a treadmill for 10 weeks. Of these, 10 rats were euthanized immediately after training (trained group), and 10 were caged without exercise for 4 weeks before being euthanized (de-trained group). The remaining 7 rats were used as controls (untrained rats). PT insertion, structure (collagen fiber organization and proteoglycan, PG, content), PT thickness, enthesis area, and subchondral bone volume at the enthesis were measured by histomorphometry and microtomography. Results: Both PG content and collagen fiber organization were significantly lower in untrained and detrained animals than in trained ones (p < 0.05 and p < 0.0001). In the detrained group, fiber organization and PG content were worse than that of the untrained groups and the untrained group showed a significantly higher score than the detrained group (p < 0.05). In the trained group, the PT was significantly thicker than in untrained group (p < 0.05). No significant differences in the enthesis area and subchondral bone volume among the three groups were seen. Conclusions: Moderate exercise exerts a protective effect on the PT structure while sudden discontinuation of physical activity has a negative effect on tendons. The present results suggest that after a period of sudden de-training (such as after an injury) physical activity should be restarted with caution and with appropriate rehabilitation programs. [ABSTRACT FROM AUTHOR]

Background: Current research aims to develop innovative approaches to improve chondral and osteochondral regeneration. The objective of this study was to investigate the regenerative potential of platelet-rich plasma (PRP) to enhance the repair process of a collagen-hydroxyapatite scaffold in osteochondral defects in a sheep model. Methods: PRP was added to a new, multi-layer gradient, nanocomposite scaffold that was obtained by nucleating collagen fibrils with hydroxyapatite nanoparticles. Twenty-four osteochondral lesions were created in sheep femoral condyles. The animals were randomised to three treatment groups: scaffold, scaffold loaded with autologous PRP, and empty defect (control). The animals were sacrificed and evaluated six months after surgery. Results: Gross evaluation and histology of the specimens showed good integration of the chondral surface in both treatment groups. Significantly better bone regeneration and cartilage surface reconstruction were observed in the group treated with the scaffold alone. Incomplete bone regeneration and irregular cartilage surface integration were observed in the group treated with the scaffold where PRP was added. In the control group, no bone and cartilage defect healing occurred; defects were filled with fibrous tissue. Quantitative macroscopic and histological score evaluations confirmed the qualitative trends observed. Conclusions: The hydroxyapatite-collagen scaffold enhanced osteochondral lesion repair, but the combination with platelet growth factors did not have an additive effect; on the contrary, PRP administration had a negative effect on the results obtained by disturbing the regenerative process. In the scaffold + PRP group, highly amorphous cartilaginous repair tissue and poorly spatially organised underlying bone tissue were found. [ABSTRACT FROM AUTHOR]

Background: This pilot study aimed to ascertain whether the local application of ascorbic acid (AA), of T3, and of rat (r) bone marrow mesenchymal stem cells (BMSCs), alone or in all possible combinations, promoted healing after an Achilles tendon injury in a rat model. Methods: An Achilles tendon defect was produced in 24 6–8-week-old male inbred Lewis rats. The animals were then randomly divided into eight groups of three rats each. The tendon defect was filled with 50 μL of phosphate-buffered saline (PBS) containing (1) 50 μg/mL AA (AA group), (2) 10−7 M T3 (T3 group), (3) 4 × 106 rBMSCs (rBMSC group), (4) 50 μg/mL AA + 10−7 M T3 (AA + T3 group), (5) 4 × 106 rBMSCs + 50 μg/mL AA (rBMSC + AA group), (6) 4 × 106 rBMSCs + 10−7 M T3 (rBMSC + T3 group), (7) 4 × 106 rBMSCS + 50 μg/mL AA + 10−7 M T3 (rBMSC + AA + T3 group), and (8) PBS only (control group: CTRL). All treatments were administered by local injection immediately after the tendons had been damaged; additionally, AA was injected also on the second and fourth day from the first injection (for groups 1, 4, 5, and 7), and T3 was injected again every day for 4 days (for groups 2, 4, 6, and 7). At 30 days from initial treatment, tendon samples were harvested, and the quality of tendon repair was evaluated using histological and histomorphological analysis. The structure and morphology of the injured Achilles tendons were evaluated using the modified Svensson, Soslowsky, and Cook score, and the collagen type I and III ratio was calculated. Results: The group treated with AA combined with T3 displayed the lowest Svensson, Soslowsky, and Cook total score value of all tissue sections at histopathological examination, with fiber structure close to regular orientation, normal-like tendon vasculature, and no cartilage formation. AA + T3 also showed the highest collagen I and the lowest collagen III values compared to all other treatments including the CTRL. Conclusion: There are potential benefits using a combination of AA and T3 to accelerate tendon healing. [ABSTRACT FROM AUTHOR]

Introduction: Cell therapy is a rapidly growing area of research for the treatment of osteoarthritis (OA). This work is aimed to investigate the efficacy of intra-articular adipose-derived stromal cell (ASC) injection in the healing process on cartilage, synovial membrane and menisci in an experimental rabbit model., Methods: The induction of OA was performed surgically through bilateral anterior cruciate ligament transection (ACLT) to achieve eight weeks from ACLT a mild grade of OA. A total of 2×10⁶ and 6×10⁶ autologous ASCs isolated from inguinal fat, expanded in vitro and suspended in 4% rabbit serum albumin (RSA) were delivered in the hind limbs; 4% RSA was used as the control. Local bio-distribution of the cells was verified by injecting chloro-methyl-benzamido-1,1'-dioctadecyl-3,3,3'3'-tetra-methyl-indo-carbocyanine per-chlorate (CM-Dil) labeled ASCs in the hind limbs. Cartilage and synovial histological sections were scored by Laverty's scoring system to assess the severity of the pathology. Protein expression of some extracellular matrix molecules (collagen I and II), catabolic (metalloproteinase-1 and -3) and inflammatory (tumor necrosis factor- α) markers were detected by immunohistochemistry. Assessments were carried out at 16 and 24 weeks., Results: Labeled-ASCs were detected unexpectedly in the synovial membrane and medial meniscus but not in cartilage tissue at 3 and 20 days from ASC-treatment. Intra-articular ASC administration decreases OA progression and exerts a healing contribution in the treated animals in comparison to OA and 4% RSA groups., Conclusions: Our data reveal a healing capacity of ASCs in promoting cartilage and menisci repair and attenuating inflammatory events in synovial membrane inhibiting OA progression. On the basis of the local bio-distribution findings, the benefits obtained by ASC treatment could be due to a trophic mechanism of action by the release of growth factors and cytokines.