Multicenter double blind trial of autologous bone marrow mononuclear cell transplantation through intracoronary injection post acute myocardium infarction - MiHeart/AMI study

Background: Myocardial infarction remains as a major cause of mortality worldwide and a high rate of survivors develop heart failure as a sequel, resulting in a high morbidity and elevated expenditures for health system resources. We have designed a multicenter trial to test for the efficacy of autologous bone marrow (ABM) mononuclear cell (MC) transplantation in this subgroup of patients. The main hypothesis to be tested is that treated patients will have a significantly higher ejection fraction (EF) improvement after 6 months than controls. Methods: A sample of 300 patients admitted with ST elevation acute myocardial infarction (STEMI) and left ventricle (LV) systolic dysfunction, and submitted to successful mechanical or chemical recanalization of the infarct-related coronary artery will be selected for inclusion and randomized to either treated or control group in a double blind manner. The former group will receive 100 x 106 MC suspended in saline with 5% autologous serum in the culprit vessel, while the latter will receive placebo (saline with 5% autologous serum). Implications: Many phase I/II clinical trials using cell therapy for STEMI have been reported, demonstrating that cell transplantation is safe and may lead to better preserved LV function. Patients with high risk to develop systolic dysfunction have the potential to benefit more. Larger randomized, double blind and controlled trials to test for the efficacy of cell therapies in patients with high risk for developing heart failure are required.

BIOMECHANICAL EVALUATION OF ORTHOPAEDIC CEMENT COMBINED WITH ANTIBIOTIC AND METHYLENE BLUE

Objective: Acrylic cement has been used for years on orthopaedic surgeries, especially on knee arthroplasties, deserving special attention when added to antibiotics (for treatment of deep bone infections) or stains (to facilitate its removal). The present study was conducted in order to evaluate potential mechanical differences between the orthopaedic cement itself and when this is added to antibiotic and/or stains. Methods: Surgical bone cement Simplex@P Stryker, vancomycin and methylene blue were used, and the mixtures were submitted to physical and mechanical tests according the ABNT NBR ISO 5833 rule. The parameters studied here were: time for mass formation, intrusion capability, resistance to compression, resistance to flexion and maximum temperature reached by the mixtures. Results: The evaluated mixtures were approved as to mass formation, maximum temperature, intrusion capability and resistance to compression. Only the one containing pure cement was approved on the flexion essay. Conclusion: The addition of vancomycin and/or methylene blue to Surgical Simplex@P Stryker bone cement reduces its resistance to flexion, being unacceptable by the ABNT NBR ISO 5833 rule.

INFLUENCE OF LASER RADIATION IN NERVE REGENERATION IN DIFFERENT TREATMENT SITES

Objective: This study seeks to determine, through functional gait assessment in different irradiation sites, the influence of a low-intensity GaAsAl laser beam on an injury caused by crushing the peroneal nerve in rats. Methods: 53 rats were used, which were divided into six groups: normal, injured and untreated, injured and treated using placebo, injured and treated in the bone marrow, injured and treated in the nerve, and injured and treated in both (nerve and bone marrow). The peroneal nerve was crushed using a pair of tweezers, and subsequently treated with laser for 28 consecutive days. The functional gait evaluation analyzed the footprints, which were recorded with a video camera on an acrylic bridge in the preoperative period, and on postoperative days 14, 21 and 28, and assessed using PFI formula software. Results: In the functional gait evaluation, significant differences were found only on postoperative day 14. Conclusion: Based on the functional gait evaluation, low-intensity GaAs AI irradiation was able to accelerate and reinforce the process of peripheral nerve regeneration in rats on postoperative day 14, both in the bone marrow- and in the nerve-treated groups.

Newly Formed Bone in Mandible Decortication Experimental Model Using rhBMP-2 Evaluated by Densitometric Study

The purpose of this study was to evaluate the newly formed bone, comparing two different carriers for rhBMP-2, using the decortication and nondecorticatication surgical technique in Wistar rat mandibles, evaluated by radiographic densitometry method. It was used fifty six animals according to specific treatment, which were sacrificed after 3 and 6 weeks after this. It was concluded that the decortication surgical technique was able to optimize the osteoinduction properties of the rhBMP-2, independently of the material carrier used and the period of time, according to radiographic densitometry technique.

Bone Deposition, Bone Resorption, and Osteosarcoma

Bone deposition and bone resorption are ongoing dynamic processes, constituting bone remodeling. Some bone tumors, such as osteosarcoma (OS), stimulate focal bone deposition. OS is the most common primary bone tumor in children and young adults. A complex network of genes regulates bone remodeling and alterations in its expression levels can influence the genesis and progression of bone diseases, including OS. We hypothesized that the expression profiles of bone remodeling regulator genes would be correlated with OS biology and clinical features. We used real-time PCR to evaluate the mRNA levels of the tartrate-resistant acid phosphatase (ACP5), colony stimulating factor-1 (CSF1R), bone morphogenetic protein 7 (BMP7), collagen, type XI, alpha 2 (COL11A2), and protein tyrosine phosphatases zeta 1 (PTPRZ1) genes, in 30 OS tumor samples and correlated with clinical and histological data. All genes analyzed, except CSF1R, were differentially expressed when compared with normal bone expression profiles. In our results, OS patients with high levels of COL11A2 mRNA showed worse overall (p = 0.041) and event free survival (p = 0.037). Also, a trend for better overall survival was observed in patients with samples showing higher expression of BMP7 (p =0.067). COL11A2 overexpression and BMP7 underexpression could collaborate to OS tumor growth, through its central role in bone remodeling process. (C) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1142-1148, 2010

Histopathology of the Hematopoietic Bone Marrow in the Temporomandibular Joint of Rats Subjected to Undernutrition and to Mandibular Condyle Fracture

Undernutrition can cause important functional and morphological alterations in the hematopoietic bone marrow (HBM). Degeneration of the HBM in malnourished individuals has been observed in the long bones, but none has been described in the cranial bones. Mandibular condyle fracture can lead to determine nutritional effects due to the high catabolism needed for the bone healing added to the difficulties of mastication. The aim of this study is to describe the histological aspect of HBM in the fractured mandibular condyle and in the temporal bone of malnourished rats. Thirty adult rats suffered unilateral mandibular condyle fracture and were divided into well-nourished (FG) and malnourished (MG) groups. In the MG the animals received a hypoproteic diet during the experiment. Histological sections of the temporomandibular joint were stained to visualize and quantify the HBM in this region at 24h, and 7, 15, 30, and 90 days post-fracture. At 24 hours, FG and MG showed hypocellularity and ischemic degeneration in the mandibular condyle and in the temporal bone. At 7 days, FG exhibited high cellularity in comparison with MG in the condyle; the temporal bone of both groups presented hypocellularity and degeneration. At 30 and 90 days, FG exhibited similar characteristics to those of the control; MG maintained the degeneration level mainly in the temporal bone. Malnutrition prejudices the regeneration of the HBM during a fracture healing in the temporomandibular joint. This fact contributes to a complete modification of the bone structure as well as to an impairment of the healing process.

Osteointegration of Autogenous Bone Graft Associated With Osteoblastic Cells Under Treatment With Caffeine

Purpose: The present study investigated osteointegration of autogenous bone (AB) from calvaria graft associated with osteoblastic cells (OC) in bone defects in rats subjected to daily administration of caffeine. Materials and Methods: Male rats received daily intraperitoneal injection of 1.5% caffeine (0.2 mL/100 g body weight) or saline solution for 30 days. Then they were anesthetized, submitted to the extraction of the upper right incisor, and implanted with AB only and AB + OC. The animals were killed on 7th, 21st, and 42nd days after surgery, and their maxilla were processed for obtaining semiserial sections (5 mu m) stained with hematoxylin and eosin. Through image analysis system, the bone volume and the quality of graft in adjacent areas were estimated. Results: The results showed that in caffeine treatment, the AB + OC graft showed no foreign body and acute inflammatory reactions inside the defect when compared to AB. The histometric results revealed that the association AB + OC produced significant increase (10%-15%) in bone volume in later experimental period (42 days) when compared with saline solution group (P <= 0.01). Conclusions: It was concluded that the association of AB from calvaria + OC demonstrated progressive osteointegration and accelerated the repair of bone defects in animals treated with daily caffeine. (Implant Dent 2011;20:369-373)

Human Alveolar Bone-Derived Cell-Culture Behaviour on Biodegradable Poly(L-lactic Acid)

Poly(L-lactic acid) (PLA) is a polymer of great technological interest, whose excellent mechanical properties, thermal plasticity and bioresorbability render it potentially useful for environmental applications, as a biodegradable plastic and as a biocompatible material in biomedicine. The interactions between an implant material surface and host cells play central roles in the integration, biological performance and clinical success of implanted biomedical devices. Osteoblasts from human alveolar bone were chosen to investigate the cell behaviour when in contact with PLA discs. Cell morphology and adhesion through osteopontin (OPN) and fibronectin (FN) expression were evaluated in the initial osteogenesis, as well as cell proliferation, alkaline phosphatase activity and bone nodule formation. It was shown that the polymer favoured cell attachment. Cell proliferation increased until 21 days but in a smaller rate when compared to the control group. On the other hand, ALP activity and bone mineralization were not enhanced by the polymer. It is suggested that this polymer favours cell adhesion in the early osteogenesis in vitro, but it does not enhance differentiation and mineralization. (C) Koninklijke Brill NV, Leiden, 2009

Effects of a mixture of growth factors and proteins on the development of the osteogenic phenotype in human alveolar bone cell cultures

Strategies to promote bone repair have included exposure of cells to growth factor (GF) preparations from blood that generally include proteins as part of a complex mixture. This study aimed to evaluate the effects of such a mixture on different parameters of the development of the osteogenic phenotype in vitro. Osteoblastic cells were obtained by enzymatic digestion of human alveolar bone and cultured under standard osteogenic conditions until subconfluence. They were subcultured on Thermanox coverslips up to 14 days. Treated cultures were exposed during the first 7 days to osteogenic medium supplemented with a GFs + proteins mixture containing the major components found in platelet extracts [plate I et-derived growth factor-BB, transforming growth factor (TGF)-beta 1, TGF-beta 2, albumin, fibronectin, and thrombospondin] and to osteogenic medium alone thereafter. Control cultures were exposed only to the osteogenic medium. Treated cultures exhibited a significantly higher number of adherent cells from day 4 onward and of cycling cells at days 1 and 4, weak alkaline phosphatase (ALP) labeling, and significantly decreased levels of ALP activity and mRNA expression. At day 14, no Alizarin red-stained nodular areas were detected in cultures treated with GFs + proteins. Results were confirmed in the rat calvaria-derived osteogenic cell culture model. The addition of bone morphogenetic protein 7 or growth and differentiation factor 5 to treated cultures upregulated Runx2 and ALP mRNA expression, but surprisingly, ALP activity was not restored. These results showed that a mixture of GFs + proteins affects the development of the osteogenic phenotype both in human and rat cultures, leading to an increase in the number of cells, but expressed a less differentiated state.

Physical Activity and Bone Mineral Accrual During Childhood and Adolescence

The epidemic that is osteoporosis has led to an increasing interest in bone mineral, and the factors that influence the levels of bone mineral, in recent years. While it is unrealistic to try and turn back the clock, a return to an increased level of physical activity may be an important consideration in terms of skeletal health. Peak bone mass is largely determined by heredity, but lifestyle and dietary patterns also influence the level of bone mineral accrued during the growing years. In this review, we summarize the evidence that vigorous weight-bearing physical activity and adequate calcium intake represent the best possibility for enhancing the attainment of an optimal level of bone mineral, within genetic limits.

Characterization of the effects of antiepileptic drugs on bone metabolism: in vitro studies with human osteoblastic and osteoclastic cells

Bone is constantly being molded and shaped by the action of osteoclasts and osteoblasts. A proper equilibrium between both cell types metabolic activities is required to ensure an adequate skeletal tissue structure, and it involves resorption of old bone and formation of new bone tissue. It is reported that treatment with antiepileptic drugs (AEDs) can elicit alterations in skeletal structure, in particular in bone mineral density. Nevertheless, the knowledge regarding the effects of AEDs on bone cells are still scarce. In this context, the aim of this study was to investigate the effects of five different AEDs on human osteoclastic, osteoblastic and co-cultured cells. Osteoclastic cell cultures were established from precursor cells isolated from human peripheral blood and were characterized for tartrate-resistant acid phosphatase (TRAP) activity, number of TRAP+ multinucleated cells, presence of cells with actin rings and expressing vitronectin and calcitonin receptors and apoptosis rate. Also, the involvement of several signaling pathways on the cellular response was addressed. Osteoblastic cell cultures were obtained from femur heads of patients (25-45 years old) undergoing orthopaedic surgery procedures and were then studied for cellular proliferation/viability, ALP activity, histochemical staining of ALP and apoptosis rate. Also the expression of osteoblast-related genes and the involvement of some osteoblastogenesis-related signalling pathways on cellular response were addressed. For co-cultured cells, osteoblastic cells were firstly seeded and cultured. After that, PBMC were added to the osteoblastic cells and co-cultures were evaluated using the same osteoclast and osteoblast parameters mentioned above for the corresponding isolated cell. Cell-cultures were maintained in the absence (control) or in the presence of different AEDs (carbamazepine, gabapentin, lamotrigine, topiramate and valproic acid). All the tested drugs were able to affect osteoclastic and osteoblastic cells development, although with different profiles on their osteoclastogenic and osteoblastogenic modulation properties. Globally, the tendency was to inhibit the process. Furthermore, the signaling pathways involved in the process also seemed to be differently affected by the AEDs, suggesting that the different drugs may affect osteoclastogenesis and/or osteoblastogenesis through different mechanisms. In conclusion, the present study showed that the different AEDs had the ability to directly and indirectly modulate bone cells differentiation, shedding new light towards a better understanding of how these drugs can affect bone tissue.

Ibuprofen-loaded poly(trimethylene carbonate-co-ϵ- caprolactone) electrospun fibres for nerve regeneration

The development of scaffolds that combine the delivery of drugs with the physical support provided by electrospun fibres holds great potential in the field of nerve regeneration. Here it is proposed the incorporation of ibuprofen, a well-known non-steroidal anti-inflammatory drug, in electrospun fibres of the statistical copolymer poly(trimethylene carbonate-co-ε-caprolactone) [P(TMC-CL)] to serve as a drug delivery system to enhance axonal regeneration in the context of a spinal cord lesion, by limiting the inflammatory response. P(TMC-CL) fibres were electrospun from mixtures of dichloromethane (DCM) and dimethylformamide (DMF). The solvent mixture applied influenced fibre morphology, as well as mean fibre diameter, which decreased as the DMF content in solution increased. Ibuprofen-loaded fibres were prepared from P(TMC-CL) solutions containing 5% ibuprofen (w/w of polymer). Increasing drug content to 10% led to jet instability, resulting in the formation of a less homogeneous fibrous mesh. Under the optimized conditions, drug-loading efficiency was above 80%. Confocal Raman mapping showed no preferential distribution of ibuprofen in P(TMC-CL) fibres. Under physiological conditions ibuprofen was released in 24h. The release process being diffusion-dependent for fibres prepared from DCM solutions, in contrast to fibres prepared from DCM-DMF mixtures where burst release occurred. The biological activity of the drug released was demonstrated using human-derived macrophages. The release of prostaglandin E2 to the cell culture medium was reduced when cells were incubated with ibuprofen-loaded P(TMC-CL) fibres, confirming the biological significance of the drug delivery strategy presented. Overall, this study constitutes an important contribution to the design of a P(TMC-CL)-based nerve conduit with anti-inflammatory properties.

The use of a modular titanium endoprosthesis in skeletal reconstructions after bone tumor resections: method presentation and analysis of 37 cases

We analyzed 37 patients who underwent segmental wide resection of bone tumors and reconstruction with a modular titanium endoprosthesis at the Orthopaedic Oncology Group, between 1992 and 1998. Twelve patients were male and 25 were female, with a mean age of 30 years (9 - 81). The mean follow-up was 14 months (2 - 48). The diagnoses were: osteosarcoma (14 cases), metastatic carcinoma (10), Ewing's sarcoma (4), giant cell tumor (4), malignant fibrous histiocytoma (3), chondrosarcoma (1), and aneurysmal bone cyst (1). Eleven articulated total knee, 8 partial proximal femur with bipolar acetabulum, 8 partial proximal humerus, 3 total femur, 2 partial proximal tibia, 2 diaphyseal femur, 2 diaphyseal humerus, and 1 total proximal femur with cementless acetabulum endoprosthesis implant procedures were done. The complications related to the procedure included: infection (5 cases), dislocation (3), module loosening (1), and ulnar nerve paresthesia (1). We used the following criteria for the clinical evaluation: presence of pain, range of motion, reconstruction stability, surgical and oncologic complications, and patient acceptance. The results were good in 56.8% of the cases, regular in 32.4% and poor in 10.8%.

Advancing tendon regeneration through the development of bio-stimulating tissue engineering approaches

Tendon tissue engineering (TE) requires tailoring scaffolds designs and properties to the anatomical and functional requirements of tendons located in different regions of the body. Cell sourcing is also of utmost importance as tendon cells are scarce. Recently, we have found that it is possible to direct the tenogenic differentiation of Amniotic fluid and Adipose tissue derived stem cells (hAFSCs and hASCs), and also that there are hASCs subpopulations that might be more prone to tenogenic differentiation. Nevertheless, biochemical stimulation may not be enough to develop functional TE substitutes for a tissue that is known to be highly dependent on mechanical loading.