Component resolved diagnosis by recombinant allergens in patients with allergies to inhalants.

Molecular characterization of IgE reactivity of specific individual components of allergenic extracts is now possible due to the technology of recombinant allergens derived from studies of molecular biology of allergic pathology. The identification of the immunoreactivity to single allergenic components in allergic subjects allows to specifically define her/his allergic profile and obtain the so-termed Component Resolved Diagnosis (CRD). Molecular allergens can be classified into those that induce the respiratory allergic reactivity and those that identify the food-related allergic pathology. It is also essential to identify those molecular allergens whose immunoreactivity is able to connect the two clinical conditions: respiratory symptoms and food allergy symptoms. The present study was conducted on 50 patients with a clinical history of hypersensitivity to pollen and/or allergy and positivity to Skin Prick Test. The sera were analyzed in our laboratories and the panel of recombinant allergens was applied in the case of positivity of the specific IgE. Of the 50 patients enrolled, 31 were selected as positive to 4 main pan-allergen Bet v1, Par j2, Art v1 and Phl p1; among these, 14 subjects showed one allergen-specific IgE towards natural extracts of tested foods even in absence of clinical history. CRD allows for an increased accuracy in allergy diagnosis and prognosis and plays an important role in: a) resolving genuine vs cross-reactive sensitization in poly-sensitized patients, b) assessing, in selected cases, the risk of severe, systemic vs mild, local reactions in food allergy, and c) identifying patients and triggering allergens for specific immunotherapy (ITS). In light of our results, we believe that the transition from a diagnostic based on the use of allergenic extracts to another one based on the use of single allergenic molecules that is able to define the specific allergenic profile of each patient, seems to be able to revolutionize the allergy diagnosis.

High incidence of MTHFR, CBS, and MTRR polymorphisms in vitiligo patients. Preliminary report in a retrospective study.

OBJECTIVE: Vitiligo is a multifactorial polygenic disorder with a complex pathogenesis. It is related to both genetic and no genetic factors. The role of genetics is currently studied with several analytical approaches, such as genetic linkage, candidate gene association studies, genome-wide association studies (GWAS), deep DNA re-sequencing and gene expression studies. To date, there are no genetic traits directly related to vitiligo pathogenesis. PATIENTS AND METHODS: 43 cases of vitiligo patients and 30 healthy donors recruited as control, were screened by assaying the biochemical molecules involved in the self-cells cytotoxicity (haptoglobin and homocysteine) and candidate genes involved in the regulatory process of the re-methylation cycles and transsulfuration. Candidate genes and their polymorphisms screened are methylene-tetrahydrofolate-reductase (MTHFR) C677T and A1298C; cystathionine-beta-synthase enzyme (CBS) I278T and Ins68bp; and methionine-synthase-reductase (MTRR) A66G. RESULTS: A peculiar genetic profile in vitiligo patients are defined: 11.6% of vitiligo patients shown polymorphic variant MTHFR 677TT vs. 3.3% of healthy donor MTHFR 677CC profile (p=0.0017); 14.0% of vitiligo patients shown CBS polymorphic variant 278TT vs. 3.3% of healthy donor 278II profile (p=0.0012); and 11.6% of vitiligo patients shown MTRR 66GG vs. 3.3% of healthy donor MTRR 677AA profile (p>0.0001). CONCLUSIONS: This is the first study reporting the correlation between the polymorphic status of MTHFR C677T, CBS I278T, and MTRR A66G and vitiligo. The genetic screening of these polymorphisms could be useful for early detection of the inheritance risk factor in a subject carrying relatives with vitiligo. Although these data could suggest a kind of dysregulation, genetically based, of thiols production mechanisms. Based on these results, we have not been able to get hypothesis about the putative pathogenesis of vitiligo, and the precise cause remains unclear.

Human cardiac multipotent adult stem cells in 3D matrix: new approach of tissue engineering in cardiac regeneration post-infarction.

Myocardial infarction is the leading cause of morbidity and mortality in developed countries. It causes a left ventricular dysfunction, mainly due to the loss of functional tissue, resulting in heart failure. New therapies are being developed, using a tissue engineering approach, with the ultimate goal of restoring cardiac function by regenerating and repairing the damaged myocardium. In the present study we investigated the behaviour of a specific population of c-kit positive human cardiac stem cells, called Multipotent Adult Stem Cells (MASCs), grown within three-dimensional collagen scaffolds (3D), to establish whether they could be used in post-infarction cardiac regeneration. We also evaluated the expression levels of the Granulocyte Macrophage-Colony Stimulating Factor Receptor (GM-CSFR) and endoglin, a component of the Transforming Growth Factor beta (TGF-ß) receptor complex. Finally, we also evaluated the expression of the α2ß1integrin. MASCs cultured within 3D collagen matrices are able to proliferate and migrate even in the absence of chemotactic agents and express high levels of factors involved in cell proliferation and migration, such as GM-CSFRα chain and integrins. They therefore represent a promising approach to tissue engineering aimed to restore cardiac function. Our results also suggest a role of GM-CSF in cell proliferation, while TGF-ß does not seem to be relevant.

Vitamin D receptor polymorphisms as tool for early screening of severe bone loss in women patients with rheumatoid arthritis.

OBJECTIVE: Rheumatoid Arthritis (RA) is an autoimmune inflammatory disease that leads to local and systemic arthritis and bone loss. Exploring genetic markers of candidate genes in osteoporosis and inflammatory cytokine genes could be a useful tool for the early identification of bone loss and fracture risk in RA patients. The target of this study is the evaluation and correlation between of Single Nucleotide Polymorphisms (SNPs) of Vitamin D Receptor (VDR) and possible effects on bone loss in RA. PATIENTS AND METHODS: 40 Caucasian patients with RA (26 of them with a severe bone loss) and 40 healthy donors as control samples were genotyped for the VDR SNPs (called BsmI, ApaI, TaqI and FokI). The detection method is based on Restriction Fragment Length Polymorphism (RFLP). RESULTS: Genotyping profile shown no difference between RA patients and controls. Only VDR-TaqI genotype (TT vs. tt) seem to influence the bone density in females, but not in males. The mean differences of Bone Mass Density (BMD) at the lumbar spine in RA women with the tt allele were 4.7% compared to 0.1% in women with the TT allele (p < 0.05). CONCLUSIONS: The results of these studies support an association between specific VDR alleles and bone loss in RA. The TaqI t and BsmI B alleles were associated with an accelerated bone loss in RA, but not with a focal bone loss. These effects of VDR genotypes and vitamin D supplementation are not unexpected, given that the central pathological feature in RA is bone and joint destruction. The VDR SNPs genotyping should be a useful tool to screen early women RA patients with the bone loss.

Effects of titanium surface topography on morphology and in vitro activity of human gingival fibroblasts.

AIM: The aim of the present study was to evaluate in vitro the biological behavior of human gingival fibroblasts cultured on two different titanium surfaces. METHODS: Titanium test disks were prepared with a machined, relatively smooth (S) surface or a rough surface (O) obtained by a double acid etching procedure. Primary cultures of human gingival fibroblasts were plated on the experimental titanium disks and cultured up to 14 days. Titanium disk surfaces were analysed by scanning electron microscopy (SEM). Cell proliferation and a quantitative analysis by ELISA in situ of ECM components as CoI, FN and TN were performed. RESULTS: Results have shown different effects of titanium surface microtopography on cell expression and differentiation. At 96 hours of culture on experimental surfaces human gingival fibroblasts displayed a favourable cell attachment and proliferation on both surfaces although showing some differences. CONCLUSION: Both the relatively smooth and the etched surfaces interacted actively with in vitro cultures of human gingival fibroblasts, promoting cell proliferation and differentiation. Results suggested that the microtopography of a double acid-etched rough surface may induce a greater Co I and FN production, thus conditioning in vivo the biological behaviour of human gingival fibroblasts during the process of peri-implant soft tissue healing.

Interferon-γ inhibits integrin-mediated extracellular signal-regulated kinase activation stimulated by fibronectin binding in thyroid cells.

Hashimoto's thyroiditis (HT) is an autoimmune disorder characterized by the presence of specific antibodies and by a lymphocytic infiltration of the thyroid secreting inflammatory cytokines. Macrophages, lymphocytes, and cytokines play a pivotal role in both development and progression of Th1-mediated autoimmune diseases, and a direct role in the destruction of thyroid follicles and follicular cell function in autoimmune thyroiditis. Integrins are integral membrane receptors involved in cell-extra-cellular matrix (ECM) interaction with both structural and signaling functions. The integrin- ECM interaction is necessary for the correct function and survival of thyroid follicular cells. The purpose of this study was to determine the effect of cytokine stimulation on integrin expression and signaling in the thyroid cell. Primary cultures from normal thyroids were treated with interferon-γ (IFN-γ), INF-α, tumor necrosis factor-α, interleukin 1a or these cytokines all together. Integrin expression, cell adhesion to fibronectin (FN) and FN-stimulated extracellular signal-regulated kinase (ERK) phosphorylation were determined after cytokine treatment. IFN-γ and IFN-α were the most effective, reducing the expression of the integrin αvß3 and slightly increasing the α3ß1. Cell treatment with IFN-γ strongly impaired cell adhesion to FN. At the same time, the treatment with IFN-γ dramatically inhibited the stimulation of ERK phosphorylation induced by cell adhesion to FN. In conclusion, IFN-γ inhibits the expression of the integrin αvß3, reducing the cell adhesion to FN and the following intracellular signaling in thyroid cells in culture. These results suggest that integrins may be a target of the infiltrating lymphocytes and have a role in the pathogenesis of autoimmune thyroiditis.

Similar serum levels of IL-6 and its soluble receptors in patients with HCV-related arthritis and rheumatoid arthritis: a pilot study.

The high serum levels of Interleukin-6 (IL-6) and its soluble receptors (sIL-6r and sgp130), described in the course of Rheumatoid Arthritis (RA), have been linked to the enhanced activity of this cytokine in this disorder. In this study, the serum concentrations of IL-6 and its soluble receptors were determined in a group of patients with HCV-related arthritis (HCVrA), a condition resembling RA in several aspects, and then compared to those found in a sample of subjects affected by RA. Twenty-one patients with HCVrA, 24 patients with RA and 20 healthy subjects (control group) were examined. Different ELISA methods were used for determination of serum concentrations of IL-6, sIL-6r and sgp130. Increased IL-6 serum levels were found in 15 (71 %) of the patients with HCVrA and in 16 (62 %) of those with RA. Eight (38 %) of the patients with HCVrA and 11 (46%) of those with RA denoted high levels of sIL-6r, while sgp130 levels were elevated in 21 (76%) of the patients with HCVrA and in 16 (69%) of those with RA. A significant difference between the median values of sIL-6r and sgp130 levels in the two groups of patients versus controls was found. A mild correlation of these parameters with RF levels was detected in the RA group. Furthermore, in HCVrA patients the serum levels of IL-6, sIL-6r and sgp130 appeared unrelated to HCV viraemia and to levels of transaminases. The enhanced serum levels of IL-6 in HCVra patients indicate an increased synthesis and hyperactivity of this cytokine in HCVrA, and the substantial similarity of the behaviour of IL-6 and its serum receptors in the two groups of patients suggests common mechanisms with RA, in which the function of I L-6 is central.

The plasminogen activator system in fibroblasts from systemic sclerosis.

Systemic sclerosis (SSc) is characterized by excessive fibrosis throughout the body. There are two major subsets of SSc, diffuse cutaneous Systemic sclerosis (dSSc) and limited cutaneous Systemic sclerosis (lSSc). Fibroblasts play a key role in SSc. The expression and function of the urokinase (uPA)-mediated plasminogen activation (PA) system, a well-characterized system of serine-proteases involved in several pathological processes, has been investigated in SSc fibroblasts. The expression of the components of the PA system, including uPA, its type-1 and type-2 inhibitors (PAI-1 and PAI-2) and its receptor (uPAR), was examined by Western blot in fibroblasts from patients affected by limited and diffuse forms of SSc. uPA and PAI-1 secretion increased only in fibroblasts from lSSc lesions compared to normal fibroblasts. PAI-2 levels were decreased in fibroblasts from both SSc forms. Interestingly, fibroblasts from areas not adjacent to the lesions (not-affected) of the diffuse form showed reduced levels of PAI-1 and increased uPAR expression. Adhesion experiments showed reduced adherence to VN of fibroblasts from lSSc lesions and from non-affected areas of the diffuse form, as compared to normal controls. These results suggest a role for uPA and PAI-1 in the lSSc form, likely related to the activation of latent forms of cytokines and to the accumulation of ECM components, whereas a role for uPAR can be hypothesized in the evolvement of the diffuse form, based on its up-regulation in the non-affected areas.

In vitro expression of osteoblastic phenotype on titanium surfaces.

AIM: Differentiation toward the osteoblastic phenotype is a complex phenomenon regulated by means of several factors. Numerous studies in vitro et in vivo showed that surface properties of titanium dental implants modulate cell proliferation and osteoblastic differentiation, affecting bone healing processes. Optimal superficial morphology is still controversial. The aim of the present study was to evaluate in vitro the effects of two different titanium surfaces on biological behaviour of human osteoblast-like cells SaOS-2 with regard to production of extra-cellular matrix (ECM) proteins. METHODS: Human osteoblast-like cells SaOS-2, cultured on commercially pure titanium disks with two different surface topographies, smooth and microstructured with sand-blasting and acid-etching treatment, were evaluated by investigating adhesion, proliferation and deposition of extra-cellular matrix (ECM) proteins Fibronectin, Tenascin and Collagen I. RESULTS: The different values of cellular adhesion at three hours and the increase of SaOS-2 proliferation values at the different experimental times on both evaluated surfaces didn't result statistically significant. ECM deposition analysis showed that Fibronectin, Tenascin and Collagen I were gradually produced, with not statistically significant differences for Fibrone-ctin and Tenascin and statistically significant differences for Collagen I. CONCLUSION: Implant surface properties modulate in vitro the biological behavior of osteoblasts-like cells SaOS-2. SaOS-2 cells proliferate on both evaluated surfaces, showing a more organized differentiation towards an osteoblastic phenotype in ECM proteins production when cultured on microstructured surface.

Anti-cyclic citrullinated peptide antibodies in patients affected by HCV-related arthritis.

Hepatitis C Virus (HCV) infection can induce immunological disorders with different clinical expressions such as arthritis, Sjogren Syndrome and various forms of vasculitis. Retrospectively, the prevalence of anti-Cyclic Citrullinated peptide antibodies (anti-CCP) in a group of patients affected by HCV-related arthritis with positivity for Rheumatoid Factor (RF) and the eventual correlations with RF and/or Anti-Nuclear Antibodies (ANA) and articular involvement were studied. Thirty patients with arthritis were selected from a population of 380 subjects affected by HCV infection. Each patient was evaluated by clinical examination (23 denoted poliarticular and 7 mono-oligoarticular involvement), by X-graphic aspects of joint involvement (8 patients presented joint erosions), by ANA, RF and anti-CCP positivity. Ten of the HCV-related arthritis patients (33.3 percent) presented positivity for anti-CCP, without significant correlation between such parameter and ANA, RF and articular involvement. Anti-CCP resulted positive in 4 out of the 8 patients with joint erosions, and only in 6 out of the 22 patients without joint erosions. Such frequencies analyzed by chi square resulted with no significant differences. Our patients presented an interesting prevalence of the positivity for anti-CCP. These data are cause to consider the specificity recently attributed to this parameter in the diagnosis of rheumatoid arthritis.

HCV infection and chronic arthritis: Does viral replication matter?

BACKGROUND: HCV infection beside chronic hepatitis can induce immunological disorders with different clinical expressions such as chronic arthritis. AIM: To study the prevalence of arthritis in HCV-Ab positive patients and verify possible correlation with viral replication, hepatic damage and autoimmunity imbalance. STUDY DESIGN: Three hundred and eighty patients (196 M and 184 F) affected by HCV infection were examined and 38 (10%) were selected according to the presence of arthritis. Eight of them were excluded because arthritis raised before HCV infection. Each patient, once undergone liver biopsy, was evaluated for: clinical examination (articular evolution), Rx examination, serum expression of hepatic damage (mainly ALT), viral replication, and involvement of autoimmunity (ANA, RF, crioglobulins, AKA, CCP). RESULTS: Data from patients [Lamprecht P, Gause A, Gross WL. Cryoglobulinemic vasculitis. Arthritis Rheum 1999; 42:2507-16.] with AKA and CCP positivity were not considered for statistical examination because the clear correlation between rheumatoid arthritis and these parameters. The remaining 20 patients showed hepatic damage 47%, viral replication in 74%, RF 42%, ANA 16%, crioglobulins 42% (RF positive). No correlation was evident between ANA serum concentrations and viral replication; furthermore a significant negative correlation between RF positivity and viral replication only in a subgroup of patients with serologic expression of hepatic damage was found. CONCLUSIONS: These data support hypothesis that the onset of arthritis and presence of autoimmunity parameters ANA, RF are not related to the viral replication but others mechanism immunological induced by HCV might be considered.

Differential expression and cytoplasm/membrane distribution of endoglin (CD105) in human tumour cell lines: Implications in the modulation of cell proliferation.

Endoglin (CD105, an accessory component of the TGF-beta receptor complex) expression and distribution on different human tumour cells and its role in cellular proliferation were evaluated. We examined: 1) sixteen human carcinoma cell lines, 2) eight human sarcoma cell lines, 3) five miscellaneous tumour cell lines. HECV (endothelial cells) were employed as a positive control for endoglin expression. Normal Human Dermal Fibroblasts (NHDF) and 293 cells (epithelial kidney cells) were used as normal controls for connective and epithelial tissues, respectively. The results showed that CD105 was poorly expressed in the majority of human carcinoma cells (10/16), whereas it was highly expressed in most human sarcoma cells (7/8), and differently expressed by miscellaneous tumour cell lines. These data reflect endoglin expression by the normal counterparts of tumour cell lines, i.e. NHDF and 293 cells. However, CD105 levels in sarcoma cell lines, even though consistently lower than in NHDF, were significantly higher than those observed in carcinoma cells. Interestingly, CD105 presented a strong expression in the cytoplasm of MDA-MB-453 (breast carcinoma), NPA (papillary thyroid carcinoma), COLO-853 (melanoma) and SaOS-2 (osteosarcoma), but was weakly expressed on their cell membrane. This differential expression in the cytoplasm and on the membrane of some tumour cells, suggests a complex mechanism of translocation for this protein. The analysis of clonal growth in soft agar of some cell lines, characterized by high CD105 expression, showed an increased colony formation potential that was antagonized by the addition of anti-CD105 blocking mAb. The results indicated that endoglin is differentially expressed in human carcinoma and sarcoma cells and its overexpression modulates the proliferative rate of human solid tumour cells. Moreover, these data suggest that CD105 is involved in the regulation of TGF-beta effects in human solid malignancies, and therefore it could play an important role in tumour diagnosis and treatment.

Different titanium surfaces modulate the bone phenotype of SaOS-2 osteoblast-like cells.

Commercially pure titanium implants presenting a relatively smooth, machined surface or a roughened endosseous surface show a large percentage of clinical success. Surface properties of dental implants seem to affect bone cells response. Implant topography appears to modulate cell growth and differentiation of osteoblasts affecting the bone healing around the titanium implant. The aim of the present study was to examine the effects of 1cm diameter and 1mm thick titanium disks on cellular morphology, adhesion and bone phenotypic expression of human osteoblast-like cells, SaOS-2. SaOS-2 cells were cultured on commercially 1 cm pure titanium disks with three different surface roughness: smooth (S), sandblasted (SB) and titanium plasma sprayed (TPS). Differences in the cellular morphology were found when they were grown on the three different surfaces. An uniform monolayer of cells recovered the S surface, while clusters of multilayered irregularly shaped cells were distributed on the rough SB and TPS surfaces. The adhesion of SaOS-2 cells, as measured after 3h of culture, was not affected by surface roughness. ECM components such as Collagen I (CoI), Fibronectin (FN), Vitronectin (VN) and Tenascin (TN) were secreted and organized only on the SB and TPS surfaces while they remained into the cytoplasm on the S surfaces. Osteopontin and BSP-II were largely detected on the SB and TPS surfaces, while only minimal production was observed on the S ones. These data show that titanium surface roughness affects bone differentiation of osteoblast like-cells, SaOS-2, indicating that surface properties may be able to modulate the osteoblast phenotype. These observations also suggest that the bone healing response around dental implants can be affected by surface topography.

Behavior of SaOS-2 cells cultured on different titanium surfaces.

Surface properties may affect the clinical outcome of titanium dental implants. The aim of the present study was to investigate the effects of 3 different titanium surfaces-smooth (S), sandblasted (SB), and titanium plasma-sprayed (TPS)-on proliferation, differentiation, and apoptosis of human osteoblast-like cells, SaOS-2. Cell proliferation was significantly (p < 0.05) higher on the S surface, and synthesis of extracellular matrix proteins was more abundant on TPS and SB than on S surfaces. Analysis of integrin receptors showed a higher expression of alpha2, alpha5, alphaVbeta3, and ss1 on TPS as compared with SB and S surfaces. An increase in alkaline phosphatase activity was detected only on SB and TPS surfaces. Analysis of cell apoptosis did not demonstrate any significant difference among the 3 different surfaces. The results indicate that titanium surface topography affects proliferation and differentiation of osteoblast-like SaOS-2 cells, suggesting that surface properties might be important for bone response around dental implants in vivo.

[Longitudinal study on osteoarthritis and bone metabolism]. / Studio longitudinale su artrosi e metabolismo osseo.

OBJECTIVE: The relationship between Osteoarthritis (OA) and Osteoporosis (OP) is not well defined due to lacking in longitudinal data, mainly regarding correlations between biochemical factors and OA incidence. Aim of this paper was to investigate the predictive value for OA incidence of bone mass variations and of selected biochemical markers in healthy women participating in a population-based longitudinal study carried out in Naples (Italy). SUBJECTS AND METHODS: High completion rate (85.2%) and statistically adequate sample size were obtained: 139 women (45 to 79 years of age) were examined and follow up visit was performed after two years (24+/-2 months), following the same protocol. Patients underwent medical examination, questionnaire, anthropometric measurements, blood sampling and urine collection. Bone mineral density (BMD) measurement was performed by dual energy X-ray absorptiometry (DEXA) at the lumbar spine (L1-L4) and femoral neck. Radiographs of dorsal and lumbar spine in lateral view were performed at basal and at 24 months visits; a team of three experts scored radiographs using Kellgren and Lawrence grading. RESULTS: The score was calculated for two individual radiographic features (narrowing of the joint space, presence of osteophytes) and as a global score. Results show a relevant percentage, 23% up, of subjects presenting both OA and OP. In the cross-sectional study the presence of osteophytosis correlates with anthropometric variables and PTH levels. In the longitudinal study results show a correlation between serum vitamin D and delta score for osteophytosis (beta=0.02 p<0.05). CONCLUSIONS: Data obtained outline the importance of further studies on the pathogenetic link between OA and bone metabolism.

Immunophenotypic analysis of human gingival fibroblasts and its regulation by Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF).

BACKGROUND: The aim of the present study was to perform an immunophenotypic analysis of human gingival fibroblast cells and its eventual modulation by Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF). METHODS: Gingival fibroblasts were derived from gingival biopsy of 15 healthy subjects. The presence of fibroblast cells in culture and the absence of epithelial cells was performed with fluorescence microscopy using vimentin and cytokeratin markers, respectively. Molecular expression of gingival fibroblast cell membrane was carried out with monoclonal antibodies by flow cytometry analysis. Human recombinant GM-CSF at the concentration of 200 ng/ml was used for the in vitro stimulation of gingival fibroblasts. Statistical analysis was performed using the Student "t"-test. RESULTS: Human gingival fibroblasts express a wide surface molecular panel including mainly CD59, CD99, CD9, CD95, CD55, CD63, CD26, CD117, CD71 and CD86. The GM-CSF seems to regulate the CD49B expression positively and the CD40 and CD103 expression negatively. CONCLUSIONS: Results show that GM-CSF is able to modulate the in vitro expression of some membrane molecules of gingival fibroblasts and therefore it may regulate, in vivo, peculiar specific biological functions of gingival tissue.

Biochemical markers of bone turnover, serum levels of interleukin-6/interleukin-6 soluble receptor and bisphosphonate treatment in Erdheim-Chester disease.

Erdheim-Chester disease (ECD) is a rare non-Langherans form of histiocytosis characterized radiologically by symmetrical sclerosis of the metaphysis and the diaphysis of long tubular bones. Macrophages are potent interleukin-6 (IL-6) producers and elevated IL-6 serum levels have been described in pathological conditions characterized by increased bone resorption. In a patient with ECD, during the acute phase of the disease we found high serum levels of IL-6 and IL-6 soluble receptor (sIL-6R) and high levels of bone turnover markers. After 5 years of combination therapy with oral prednisone and intravenous clodronate a significant reduction in the above mentioned biological parameters was seen. We suggest that the systemic disorders present in ECD could be related to the high serum levels of IL-6 and sIL-6R. We also propose the use of bisphosphonates in the clinical management of ECD.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces the osteoblastic differentiation of the human osteosarcoma cell line SaOS-2.

The Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) is a hematopoietic growth factor that regulates the in vitro and in vivo proliferation and differentiation of hematopoietic cells through the interaction with a specific heterodimeric receptor complex (GM-CSFR), consisting of an alpha and a beta chain with molecular weights of 80 and 120 KDa, respectively. We have studied the expression of the GM-CSFR (alpha chain) on the surface of the human osteosarcoma cell line SaOS-2 and the in vitro effects of different concentrations (10, 100, and 200 ng/ml) of GM-CSF on GM-CSFR expression and the biological activity of SaOS-2 cells. Our data show that SaOS-2 cells express GM-CSFR and that GM-CSF can down-regulate the expression of its own receptor on these cells. Furthermore, to evaluate the biological effects of GM-CSF on SaOS-2 cells, we have investigated cell proliferation and differentiation of these cells treated with different doses of the growth factor through: (1) a morphological analysis of typical osteoblast differentiation markers such as osteopontin and BSP-II; (2) measurement of alkaline phosphatase (ALP) activity; (3) production of bone ECM components (collagen I, fibronectin, tenascin, and laminin); (4) production of interleukin-6 (IL-6) and osteocalcin in the culture medium. The results show that the in vitro treatment of SaOS-2 cells with recombinant human GM-CSF causes a decreased cell proliferation and an increased production of osteopontin, BSP-II, ALP, IL-6, and most but not all ECM components. These findings suggest that GM-CSF can regulate proliferation and differentiation of osteoblast-like SaOS-2 cells and could also play an unexpected role in the maturation of bone tissue.

Effect of human granulocyte macrophage-colony stimulating factor on differentiation and apoptosis of the human osteosarcoma cell line SaOS-2.

We investigated the effects of human granulocyte macrophage-colony stimulating factor (GM-CSF) on the relation between differentiation and apoptosis in SaOS-2 cells, an osteoblast-like cell line. To determine the relationship between these cellular processes, SaOS-2 cells were treated in vitro for 1, 7 and 14 days with 200 ng/mL GM-CSF and compared with untreated cells. Five nM insulin-like growth factor (IGF-I) and 30 nM okadaic acid were used as negative and positive controls of apoptosis, respectively. Effects on cell differentiation were determined by ECM (extracellular matrix) mineralization, morphology of some typical mature osteoblast differentiation markers, such as osteopontin and sialoprotein II (BSP-II), and production of bone ECM components such as collagen I. The results showed that treatment with GM-CSF caused cell differentiation accompanied by increased production of osteopontin and BSP-II, together with increased ECM deposition and mineralization. Flow cytometric analysis of annexin V and propidium iodide incorporation showed that GM-CSF up-regulated apoptotic cell death of SaOS-2 cells after 14 days of culture in contrast to okadaic acid, which stimulated SaOS-2 apoptosis only during the early period of culture. Endonucleolytic cleavage of genomic DNA, detected by "Aúladdering analysis"Aù, confirmed these data. The results suggest that GM-CSF induces osteoblastic differentiation and long-term apoptotic cell death of the SaOS-2 human osteosarcoma cell line, which in turn suggests a possible in vivo physiological role for GM-CSF on human osteoblast cells.