Long-term Insights: Histopathological Assessment of Polyurethane Implant Capsules Over 24 Years.

BACKGROUND: Polyurethane (PU)-coated breast implants are known for their strong integration into breast tissue and the formation of capsules around them. However, capsular contracture can pose both aesthetic and clinical challenges. OBJECTIVES: The objectives of this study were to analyze the biological and morphological characteristics of the capsular tissue surrounding PU-coated implants, irrespective of their contracture status, and to assess their potential suitability as a flap in revisional breast surgery for capsular contracture. METHODS: A total of 23 tissue samples were harvested from the capsules surrounding PU-coated breast implants in 12 female patients during replacement or revisional surgery. We evaluated collagen abundance, cellular and vascular density, inflammation, collagen band types and alignment, synovial metaplasia, capsule thickness, and the expression of inflammatory biomarkers and myofibroblasts with immunohistochemical techniques. Scanning electron microscopy was employed to assess implant surface characteristics over time. RESULTS: We found a significant association of capsule contraction with longer implantation durations and greater implant surface roughness (P = .018 and P = .033, respectively). Synovial metaplasia was significantly more frequent in noncontracted capsules (P = .0049). Both capsule types consisted of paucicellular, type I collagen-rich compact fibrous tissue with low vascularization. There was a marked reduction in inflammatory cells within the foreign body granuloma. The expression of inflammatory biomarkers in the capsular tissue was negligible. CONCLUSIONS: Given the reduced levels of inflammatory and vascular components within the dense, fibrous capsular tissue, we consider them to be viable alternatives for capsular flaps in revisional surgery. This strategy has the potential to mimic the reconstruction achieved with acellular dermal matrix.

The effect of bone allografts combined with bone marrow stromal cells on the healing of segmental bone defects in a sheep model.

BACKGROUND: The repair of large bone defects is a major orthopedic challenge because autologous bone grafts are not available in large amounts and because harvesting is often associated with donor-site morbidity. Considering that bone marrow stromal cells (BMSC) are responsible for the maintenance of bone turnover throughout life, we investigated bone repair at a site of a critically sized segmental defect in sheep tibia treated with BMSCs loaded onto allografts. The defect was created in the mid-portion of the tibial diaphysis of eight adult sheep, and the sheep were treated with ex-vivo expanded autologous BMSCs isolated from marrow aspirates and loaded onto cortical allografts (n = 4). The treated sheep were compared with control sheep that had been treated with cell-free allografts (n = 4) obtained from donors of the same breed as the receptor sheep. RESULTS: The healing response was monitored by radiographs monthly and by computed tomography and histology at six, ten, fourteen, and eighteen weeks after surgery. For the cell-loaded allografts, union was established more rapidly at the interface between the host bone and the allograft, and the healing process was more conspicuous. Remodeling of the allograft was complete at 18 weeks in the cell-treated animals. Histologically, the marrow cavity was reestablished, with intertrabecular spaces being filled with adipose marrow and with evidence of focal hematopoiesis. CONCLUSIONS: Allografts cellularized with AOCs (allografts of osteoprogenitor cells) can generate great clinical outcomes to noncellularized allografts to consolidate, reshape, structurally and morphologically reconstruct bone and bone marrow in a relatively short period of time. These features make this strategy very attractive for clinical use in orthopedic bioengineering.

Secreted phosphoprotein 24 kD (Spp24) inhibits the growth of human osteosarcoma through the BMP-2/Smad signaling pathway.

Autocrine stimulation of tumor cells is an important mechanism for the growth of skeletal tumors. In tumors that are sensitive, growth factor inhibitors can dramatically reduce tumor growth. In this study, our aim was to investigate the effects of Secreted phosphoprotein 24 kD (Spp24) on the growth of osteosarcoma (OS) cells in the presence and absence of exogenous BMP-2 both in vitro and in vivo. Our study demonstrated that Spp24 inhibited proliferation and promoted apoptosis of OS cells as confirmed by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay and immunohistochemical staining. We found that BMP-2 increased the mobility and invasiveness of tumor cells in vitro whereas Spp24 inhibited both of these processes alone and in the presence of exogenous BMP-2. Phosphorylation of Smad1/5/8 and Smad8 gene expression was enhanced by treatment with BMP-2 but inhibited by treatment with Spp24. Subcutaneous and intratibial tumor models in nude mice demonstrated that BMP-2 promoted OS growth in vivo, while Spp24 significantly inhibited tumor growth. We conclude that the BMP-2/Smad signaling pathway is involved in the pathogenesis of OS growth and that Spp24 inhibits the growth of human OS induced by BMP-2 both in vitro and in vivo. Interruption of Smad signaling and increased apoptosis appear to be the primary mechanisms involved. These results confirm the potential of Spp24 as a therapeutic agent for the treatment of OS and other skeletal tumors.

The Manufacture of GMP-Grade Bone Marrow Stromal Cells with Validated In Vivo Bone-Forming Potential in an Orthopedic Clinical Center in Brazil.

In vitro-expanded bone marrow stromal cells (BMSCs) have long been proposed for the treatment of complex bone-related injuries because of their inherent potential to differentiate into multiple skeletal cell types, modulate inflammatory responses, and support angiogenesis. Although a wide variety of methods have been used to expand BMSCs on a large scale by using good manufacturing practice (GMP), little attention has been paid to whether the expansion procedures indeed allow the maintenance of critical cell characteristics and potency, which are crucial for therapeutic effectiveness. Here, we described standard procedures adopted in our facility for the manufacture of clinical-grade BMSC products with a preserved capacity to generate bone in vivo in compliance with the Brazilian regulatory guidelines for cells intended for use in humans. Bone marrow samples were obtained from trabecular bone. After cell isolation in standard monolayer flasks, BMSC expansion was subsequently performed in two cycles, in 2- and 10-layer cell factories, respectively. The average cell yield per cell factory at passage 1 was of 21.93 ± 12.81 × 106 cells, while at passage 2, it was of 83.05 ± 114.72 × 106 cells. All final cellular products were free from contamination with aerobic/anaerobic pathogens, mycoplasma, and bacterial endotoxins. The expanded BMSCs expressed CD73, CD90, CD105, and CD146 and were able to differentiate into osteogenic, chondrogenic, and adipogenic lineages in vitro. Most importantly, nine out of 10 of the cell products formed bone when transplanted in vivo. These validated procedures will serve as the basis for in-house BMSC manufacturing for use in clinical applications in our center.

Immediate dental implant failure associated with nasopalatine duct cyst.

This case report presents an analysis of the clinical, radiographic, and histological features of a peri-implant lesion around an implant placed immediately after extraction of a tooth with a periapical lesion. A 52-year-old man received an immediate implant (3.75 x 11.5 mm2) placed in the anterior region of the maxilla. Three years after implant placement, the patient presented with swelling in the anterior portion of the maxilla. Radiographic examination showed a well-circumscribed radiolucency around the implant. The implant and the lesion were removed and fixed in 10% buffered formalin and processed. Histological analysis showed 3 types of epithelium: respiratory, cuboidal, and non-keratinized stratified squamous. In the cyst wall peripheral nerves, arteries, veins, and chronic inflammation were present. The diagnosis was nasopalatine duct cyst. We concluded that the nasopalatine duct cyst can develop in association with dental implants. Clinically, the lesion is similar to the classical nasopalatine duct cyst. Histological analysis should be mandatory in all cases of peri-implant lesions and in all dental periapical lesions before immediate implant placement.

Atrophic nonunion stromal cells form bone and recreate the bone marrow environment in vivo.

INTRODUCTION: Nonunion is a challenging condition in orthopaedics as its etiology is not fully understood. Clinical interventions currently aim to stimulate both the biological and mechanical aspects of the bone healing process by using bone autografts and surgical fixation. However, recent observations showed that atrophic nonunion tissues contain putative osteoprogenitors, raising the hypothesis that its reactivation could be explored to achieve bone repair. METHODS: Here we characterized atrophic nonunion stromal cells (NUSC) in vitro, using bone marrow stromal cells (BMSC) and osteoblasts as controls cells of the osteoblastic lineage, and evaluated its ability to form bone in vivo. RESULTS: NUSC had proliferative and senescence rates comparable to BMSC and osteoblasts, and homogeneously expressed the osteolineage markers CD90 and CD73. Regarding CD105 and CD146 expression, NUSC were closely related to osteoblasts, both with an inferior percentage of CD105+/CD146+ cells as compared to BMSC. Despite this, NUSC differentiated along the osteogenic and adipogenic lineages in vitro; and when transplanted subcutaneously into immunocompromised mice, new bone formation and hematopoietic marrow were established. CONCLUSIONS: This study demonstrates that NUSC are osteogenically competent, supporting the hypothesis that their endogenous reactivation could be a strategy to stimulate the bone formation while reducing the amount of bone autograft requirements.

Bone intramedullary reaming grafts the fracture site with CD146+ skeletal progenitors and downmodulates the inflammatory environment.

INTRODUCTION: Femoral shaft fractures generally occur in young adults following a high-energy trauma and are prone to delayed union/non-union. Novel therapies to stimulate bone regeneration will have to mimic some of the aspects of the biology of fracture healing; however, which are these aspects is unclear. Locked intramedullary nailing is the current treatment of choice for the stabilisation of femur shaft fractures, and it is associated with accelerated healing and increased union rates. These benefits were partially attributed to the reaming procedure, which, regardless of significantly destroying the haematoma, stimulates the healing response. To better understand how reaming influences healing, we evaluated the viability of the nucleated cell fraction and the frequency of CD146+ skeletal progenitors, which contain multipotent cells, in the post-reaming haematoma. We also screened the concentrations of inflammatory mediators and growth factors in the fracture site after reaming compared with those in the original haematoma. METHODS: Pre- and post-reaming haematomas were percutaneously aspirated from the fracture site of 15 patients with closed femoral shaft fractures. Cellular viability and the percentage of CD146+ progenitors were analysed by flow cytometry. The concentrations of cytokines and growth factors were determined by ELISA. RESULTS: AnnexinV/Pi analysis showed that the viability of the total nucleated cell fraction was decreased in the post-reaming haematoma. However, the procedure increased the percentage of CD146+ skeletal progenitors in the fracture site. Analysis of cytokines and growth factors in supernatants showed a decreased concentration of the inflammatory mediators IL-6, CCL-4, and MCP-1, along with an increase of anti-inflammatory IL-10, and the growth factors bFGF and PDGF-AB. CONCLUSION: These findings support the view that the positive effects of reaming on fracture healing might result from mechanically grafting the fracture site with a population of skeletal progenitors that contain multipotent cells; transitioning the signalling environment to a less inflammatory state, and enhancing the availability of specific osteogenic and angiogenic factors. A better understanding of the requisite stimuli for optimal bone repair, considering the disturbances made by orthopaedic treatments, will be determinant for the development of innovative treatments for bone repair.

The effects of dietary restriction on humeral and mandibular bone in SENCAR, C57BL/6, and DBA/2 mice.

Dietary restriction (DR) increases the life span and retards the development of age-related disorders. However, the low body mass that accompanies DR is associated with risk factors for fracture that may outweigh the beneficial effects of DR on cellular aging that are mediated, in part, by limiting free radical generation and oxidative damage. We tested the effects of DR in murine models that differ in free radical generation capacity (SENCAR > C57 > DBA). Male mice of each strain were killed at 10 weeks of age (t(0); time zero) or randomized to an ad libitum-fed (AL-fed) or 30% DR feeding regimen for 6 months. The food consumption of AL-fed mice was measured daily. DR mice received 70% of the amount of food consumed by their respective AL-fed mice the previous day. The DR diet was normalized with respect to calcium (Ca), phosphorus (P), and micronutrients. Lean body mass (LBM), bone mineral density (BMD), and bone mineral content (BMC) in the humerus and mandible were determined by PIXImus densitometry. The length and midshaft width of the humerus were determined by direct measurement. There were highly strain- and diet/time-dependent effects on LBM, humerus length, mandibular and humeral BMD, and humeral BMC. The interaction between diet/time and strain was more significant in the humerus than the mandible. All 30% DR mice had lower humeral BMDs and BMCs than their respective AL-fed controls. However, 30% DR C57 and DBA (but not SENCAR) mice had higher humeral BMD and BMC than their respective t(0) controls. There was a linear relationship between LBM and humeral BMD and BMC in both AL-fed and 30% DR mice, suggesting that the lower BMD and BMC in 30% DR mice, relative to AL-fed controls, reflects a physiologic adaptation to lower biomechanical loading. Mandibular BMC in 30% DR C57 (but not DBA or SENCAR) mice was lower than that observed in their AL-fed controls. Mandibular BMD and BMC increased versus t(0) values in 30% DR mice of all strains.

Surgical treatment for unstable pelvic fractures in skeletally immature patients.

OBJECTIVE: To present the results and conclusions of our study on surgical treatment for unstable pelvic fractures in children subjected to surgical reduction and stabilisation. METHODS: We analysed the cases of fourteen skeletally immature patients with unstable pelvic fractures who underwent surgery for this condition between March 2004 and January 2011. The surgical technique used was based on the principle of surgical reduction and stabilisation of anterior and posterior lesions of the pelvic ring. This was a retrospective study, based on clinical assessment and X-ray analyses. RESULTS: The mean age of patients at the time of the condition was 9.4 years (range 2-13 years). Eight patients were female and six were male. The cause of the trauma was being hit by a car in ten cases, falls in three cases and an accident involving a motorcycle in one case. Five patients presented with other associated injuries, including fracture of the clavicle, femur shaft, proximal humerus, tibial shaft or olecranon, and bladder damage. All the patients assessed showed excellent clinical progress. Pelvic asymmetry prior to surgery varied from 1.1 to 2.9 cm (mean 1.5 cm) and dropped to a range of 0.2 to 0.9 cm (mean 0.4 cm) after reduction. In none of the cases was there a change between the pelvic asymmetry measured immediately after surgery and at the end of the follow-up period. CONCLUSION: Pelvic fracture in skeletally immature patients is rare and surgery is not normally indicated. Various authors have questioned this conservative type of treatment due to complications encountered. Bone remodelling does not seem to be sufficient to ensure an improvement in pelvic asymmetry, which justifies opting for surgery to reduce and correct deformities in the pelvic ring.

The effect of autologous concentrated bone-marrow grafting on the healing of femoral shaft non-unions after locked intramedullary nailing.

The aim of this study was to assess the union rates in a series of patients with failed femoral shaft aseptic non-union who were treated with percutaneous concentrated autologous bone marrow grafting. Bone marrow harvesting and cell injection were performed under general anaesthesia in a single surgical procedure. Radiographic union was diagnosed in fractures with a score ≥ 10 according to the radiographic union scale in tibial fractures (RUST) and confirmed by clinical examination. Eight out of 16 patients progressed to consolidation (RUST score ≥ 10). Radiographic evidence of fracture union was observed at an average of 4.75 ± 1.75 months (range 3 to 8 months). All eight patients who did not progress to union within 12 months following the cell grafting procedure had a RUST score ≤ 10 (range 4 to 9). There were no differences in age, number of previous surgeries, duration of nonunion and preoperative RUST score between the patients that developed solid union and those with failed consolidation. However, a relationship between the number of osteoprogenitors injected and the rate of union was noted, 20.2 ± 8.6 × 10(8) versus 9.8 ± 4.3 × 10(8), p<0.005, between the patients with and without union, respectively. The efficacy of percutaneous autologous concentrated bone marrow grafting seems to be related to the number of osteoprogenitors available in the aspirates. Optimisation of the aspiration technique and concentration process is of paramount importance to increase the incidence of a successful outcome.

Efeito anti-tumoral dos bisfosfonatos: uma nova perspectiva terapêutica / Anti-tumor effect of bisphosphonates: a new therapeutic perpective

Os bisfosfonatos (BFs) são potentes inibidores da reabsorção óssea mediada por osteoclastos. Essas drogas sãoefetivas na redução do cálcio sérico em pacientes com hipercalcemia maligna, assim como também no tratamentoda dor óssea, osteoporose e metástases ósseas.Diversos estudos demonstram que os BFs possuem efeito em outras células além dos osteoclastos. Em célulastumorais podem agir induzindo a apoptose, inibindo a proliferação celular, inibindo a adesão e a invasividadecelular ou as metástases ósseas. O mecanismo molecular subjacente a estes efeitos parece ser a inibição de enzimasda via do mevalonato, o que leva a um impedimento da prenilação de GTPases como Ras e Rho, importantes paraa manutenção da integridade do citoesqueleto e tráfego de vesículas nas células.As evidências dos recentes estudos laboratoriais e clínicos sugerem que os BFs têm um papel importante comotratamento suplementar e possivelmente complementar na terapia do câncer. Um entendimento mais profundo e completo sobre o efeito anti-tumoral destas drogas pode sugerir possibilidades terapêuticas novas e seletivas.

Bisphosphonates are potent osteoclast-mediated bone reabsorption inhibitors. These drugs are effective in reducingserum calcium levels in patients with malignant hypercalcaemia, as well as in bone pain, osteoporosis and bonemetastasis treatment. Several studies have demonstrated that bisphosphonates are effective in other cell types than osteoclasts. In tumourcells they can act inducing apoptosis, inhibiting cell proliferation, inhibiting cell adhesion and invasion or bonemetastasis. The underlying molecular mechanism to these effects seems to be the inhibition of mevalonate pathwayenzymes, which leads to a prenilation impairment of GTPases like Ras and Rho, important in maintaining celularcytoskeleton integrity and vesicles trafficking. Evidences from recent laboratorial and clinical studies suggest that bisphosphonates have an important role as a supplemental, and possibly as complementary treatment in cancer therapy. A more complete understanding concerning the anti-tumor effect of these drugs may suggest new and selective therapeutical possibilities.