Fetuin-A is related to syndesmophytes in patients with ankylosing spondylitis: a case control study

OBJECTIVES: New bone formation is one of the hallmark characteristics of ankylosing spondylitis, which is thereby associated with syndesmophytes. Fetuin-A is a molecule that is abundantly found in calcified tissues and it shows high affinity for calcium phosphate minerals and related compounds. Considering the role of fetuin-A in the regulation of calcified matrix metabolism, we compared the fetuin-A levels in ankylosing spondylitis patients with syndesmophytes with those in patients without syndesmophytes and in healthy controls. We also studied other biomarkers that are thought to be related to syndesmophytes. METHODS: Ninety-four patients (49 patients without syndesmophytes, 67.3% male, 40.7±8.7 years; 45 patients with syndesmophytes, 71.1% M, 43.9±9.9 years) and 68 healthy controls (44.2±10.6 years and 70.6% male) were included in this study. Syndesmophytes were assessed on the lateral radiographs of the cervical and lumbar spine. The serum levels of fetuin-A, dickkopf-1, sclerostin, IL-6, high-sensitivity C-reactive protein and bone morphogenetic protein-7 were measured with an enzyme-linked immunosorbent assay. RESULTS: Patients with syndesmophytes had significantly higher levels of fetuin-A compared with patients without syndesmophytes and controls (1.16±0.13, 1.05±0.09 and 1.08±0.13 mg/ml, respectively). However, fetuin-A was not different between the patients without syndesmophytes and controls. Bone morphogenetic protein-7 was significantly lower; dickkopf-1 was significantly higher in patients with ankylosing spondylitis compared with controls. The sclerostin concentrations were not different between the groups. In regression analysis, fetuin-A was an independent, significant predictor of syndesmophytes. CONCLUSION: Our results suggest that fetuin-A may a role in the pathogenesis of bony proliferation in ankylosing spondylitis. .

Phenotypic Characterization of Ligamentum Flavum Cells from Patients with Ossification of Ligamentum Flavum

PURPOSE: The objective of this study was to determine the phenotypic characterization of ligamentum flavum cells from patients with ossification of the ligamentum flavum (OLF). MATERIALS AND METHODS: Ligamentum flavum tissues were harvested from OLF and non-OLF patients during surgery. OLF and non-OLF cells were isolated from explant cultures. Cultured cells were analyzed using immunofluorescence staining and reverse transcription-polymerase chain reaction. RESULTS: OLF cells exhibited various appearances compared with the typical fibroblast-like morphology of non-OLF cells. Expressions of collagen type I and collagen type III were observed in OLF and non-OLF cells. OLF cells uniquely expressed osteocalcin, which is a marker for osteoblasts, and collagen type II which is a marker for chondrocytes, whereas they were negative in non-OLF cells. CONCLUSION: These findings indicate that OLF cells have phenotypic characterization of osteoblasts and chondrocytes which could play a role in the pathophysiology of OLF.

Osso liofilizado bovino não-desmineralizado com células-tronco mesenquimais para engenharia tecidual: estudo experimental em sítio heterotópico / Bovine non-demineralized lyophilized bone with mesenchymal stem cells for tissue engineering: experimental study in heterotopic site

Objetivo: Avaliar o uso de células da medula óssea, com potencial osteogênico, agregadas a estrutura tridimensional de osso liofilizado bovino não-desmineralizado para engenharia tecidual óssea. Método: Os animais doadores de células da medula óssea, assim como os animais receptores dos construtos ósseos, foram camundongos de linhagem isogênica C57Bl/6. Utilizou-se modelo experimental heterotópico, com a implantação de construtos de osso liofilizado bovino não-desmineralizado (OL) no plano subcutâneo no dorso dos animais. Foram organizados 4 grupos de comparação (n=10 animais em cada grupo): 1) OL isoladamente (grupo controle); 2) OL + células mononucleares da medula (CMM); 3) OL + células-tronco mesenquimais (CTM); 4) OL + células-tronco mesenquimais diferenciadas em meio osteoindutor (CTMdif). A aferição foi realizada após 5 semanas, com avaliação histológica e determinação da atividade de fosfatase alcalina. Resultados: A avaliação histológica não mostrou diferença entre os grupos de comparação, com a observação em todas as amostras de tecido conjuntivo fibroso rico em neovasos estendendo-se por entre as trabéculas ósseas, sem osteoblastos ou osteócitos viáveis e sem neoformação óssea. Os resultados da atividade de fosfatase alcalina também não mostraram diferença entre os grupos de comparação, com análise de variância entre os grupos mostrando p=0,867. Conclusões: Os resultados mostraram que, no modelo estudado e com os métodos utilizados, a adição de células da medula óssea com potencial osteogênico sobre estrutura de osso liofilizado bovino não-desmineralizado não agregou propriedades osteogênicas ao material. Este estudo não confirmou a perspectiva inicial de utilizá-lo como estrutura tridimensional e carreadora celular na engenharia tecidual óssea, sendo necessários estudos subseqüentes que o avaliem em outros modelos experimentais, e que explorem separadamente cada etapa metodológica que possa influir no sucesso da engenharia tecidual óssea.

Objective: To evaluate the use of bone marrow cells with osteogenic potential seeded on bovine nondemineralized lyophilized bone scaffolds for bone tissue engineering. Method: Bone marrow cells donors, as well as the receptors of the bone constructs were C57BI/6 isogenic line mice. A heterotopic experimental model was used, with implantation of the constructs into subcutaneous pouches on the backs of the animals. Four comparison groups were set (n=10 animals each group): 1) LB alone (control group); 2) LB + marrow mononuclear cells (MMC); 3) LB + mesenchymal stem cells (MST); 4) LB + mesenchymal stem cells differentiated in osteoinductive medium (MSTdif). The constructs were harvested 5 weeks after implantation for histological analysis and alkaline phosphatase activity test. Results: The histological analysis did not show differences among the comparison groups. In all samples fibrous connective tissue rich in neovessels was observed extending through bone trabeculae, without viable osteoblasts or osteocytes and without new bone formation. Likewise, results of the alkaline phosphatase activity have not shown any difference among comparison groups, with the analysis of variance between groups showing p value=0.867. Conclusions: In this experimental model and with the methods used, the addition of bone marrow cells with osteogenic potential to a bovine non-demineralized lyophilized bone structure did not add osteogenic properties to the material. The initial perspective of using it as a scaffold for bone tissue engineering could not be confirmed, and further studies are required to assess it in other experimental models, and to explore separately each methodological step that might influence the success of bone tissue engineering.