Biomedical subjects

L Savarino

Publications and source records attributed to L Savarino.

At least 19 recordsLinked to original sources

PubMed2007

Potential of FeAlCr intermetallics reinforced with nanoparticles as new biomaterials for medical devices.

Novel FeAlCr oxide dispersion strengthened intermetallics that are processed by powder metallurgy have been developed as potential biomaterials. The alloys exhibit a small grain size and a fine dispersion of yttria provides the material with a high yield strength and depending on the alloy composition good ductility (up to 5%). The biocompatibility of the alloy was assessed in comparison with commercial alumina. Saos-2 osteoblast-like cells were either challenged with mechanically alloyed particles, or seeded onto solid samples. Viability and proliferation of cells were substantially unaffected by the presence of a high concentration of particles (1 mg/mL). Solid samples of novel FeAlCr intermetallic have shown a good biocompatibility in vitro, often approaching the behavior of materials well known for their biological acceptance (e.g. alumina). It has been found that osteoblasts are able to produce ALP, a specific marker of cells with bone-forming activity. In this respect, ALUSI alloys hold the promise to be suitable substrate for bone integration. The finding of no cytotoxic effect in the presence of the alloy particles is a reliable proof of the absence of acute toxicity of the material.

Alkaline Phosphatase↗

PubMed2006

Evaluation of bone healing enhancement by lyophilized bone grafts supplemented with platelet gel: a standardized methodology in patients with tibial osteotomy for genu varus.

Orthopedic practice may be adversely affected by an inadequate bone repair that might compromise the success of surgery. In recent years, new approaches have been sought to improve bone healing by accelerating the rate of new bone formation and the maturation of the matrix. There is currently great interest in procedures involving the use of platelet gel (PG) to improve tissue healing, with satisfactory results both in vitro and in maxillofacial surgery. Otherwise, to our knowledge, only a preliminary clinical study was undertaken in the orthopedic field [Kitoh et al., Bone 2004;35:892-898] and the efficacy of PG is still controversial. Our paper focuses on the effect on bone regeneration by adding PG to lyophilized bone chips used for orthopedic applications. The clinical model and the laboratory methodology were standardized. As a clinical model, we employed the first series of patients of a randomized case-control study undergoing high tibial osteotomy (HTO) for genu varus. Ten subjects were enrolled: in 5 patients lyophilized bone chips supplemented with PG were inserted during tibial osteotomy (group A); 5 patients were used as a control (group B) and lyophilized bone chips without gel were applied. Forty-five days after surgery, computed tomography scan guided biopsies of grafted areas were obtained and the bone maturation was evaluated by a standardized methodology: the osteogenic and angiogenic processes were semi-quantitatively characterized by using histomorphometry, and the mineral component of the lyophilized and host bone was analyzed by using X-ray diffraction technique with sample microfocusing and microradiography. Lyophilized bone with PG seems to accelerate the healing process, as shown by new vessel formation and deposition of newly formed bone, with no evidence of inflammatory cell infiltrate, when compared with lyophilized bone without gel. On the contrary, lyophilized bone undergo a resorption process, and a fibrous tissue often fills the spaces between chips. A histiocytic/giant-cell reaction is sometimes present. Otherwise, no differences have been found concerning microstructure. Our findings show the reliability of the methodology used to monitor early bone repair. The completion of the study and the evaluation of the ultimate clinical outcome are necessary in order to verify PG in vivo effects in orthopedic surgery.

Adult↗

PubMed2006

Differences in ion release after ceramic-on-ceramic and metal-on-metal total hip replacement. Medium-term follow-up.

Modern metal-on-metal bearings produce less wear debris and osteolysis, but have the potential adverse effect of release of ions. Improved ceramic-on-ceramic bearings have the lowest wear of all, but the corrosion process has not been analysed. Our aim was to measure the serum ion release (ng/ml) in 23 patients having stable hip prostheses with a ceramic-on-ceramic coupling (group A) and to compare it with the release in 42 patients with a metal-on-metal bearing (group B) in the medium term. Reference values were obtained from a population of 47 healthy subjects (group C). The concentrations of chromium, cobalt, aluminium and titanium were measured. There was a significant increase of cobalt, chromium and aluminium levels (p < 0.05) in group B compared with groups A and C. Group A did not differ significantly from the control group. Despite the apparent advantage of a metal-on-metal coupling, especially in younger patients with a long life expectancy, a major concern arises regarding the extent and duration of ion exposure. For this reason, the low corrosion level in a ceramic-on-ceramic coupling could be advantageous.

Adult↗

PubMed2005

A preliminary in vitro and in vivo study of the effects of new anthraquinones on neutrophils and bone remodeling.

Osteolysis, that is, progressive periprosthetic bone loss, is responsible for approximately 70% of aseptic loosening and implant failure. Usually, it is due to a granulomatous reaction wear-induced, leading to macrophage and osteoclast-mediated bone resorption. At present, there is no established prophylaxis or treatment for this process. For this purpose, as a preliminary investigation, we aimed to study the effects in two directions, inhibition of proinflammatory signals, and bone remodeling activity, of two newly synthesized anthraquinone molecules [N,N'-Diethylamino-2,6-anthraquinone-disulfonamide (GR375) and N,N'-(p-ethoxyphenyl)-2,6-anthraquinone-disulfon amide (GR377)]. Among the pro-inflammatory signals, the ability of the two anthraquinones to interfere with the production of superoxide anion (O(2) (-)), which was assumed as a marker of reactive oxygen species (ROS), was evaluated in an in vitro cell model by testing phagocytes, such as human neutrophils, challenged by the chemotactic agent N-formylmethionyl-leucyl-phenylalanine (FMLP). Both compounds inhibited O(2) (-) production, in a dose-dependent way, without exerting scavenger effects. An in vivo model was applied to investigate their effect on bone remodeling. Fifty-four female Wistar rats were divided into eight groups of six animals each, and a 4-week treatment was applied in two phases. A 25 mg/kg/os dose in the first phase and 12.5-6.25 mg/kg/os doses in the second one were employed. The tibia trabecular bone at the secondary spongiosa level was analyzed, and trabecular bone volume (%TBV), trabecular thickness (TbTh), and apatite lattice parameters were measured. At the highest doses of GR375 and GR377 the %TBV and the TbTh increased by 33.2, 34.6%, and 3.6 and 9.1%, respectively, whereas crystallographic parameters were not significantly different from the untreated group. Our results suggest a simultaneous antiinflammatory and antiosteoclastic activity of both drugs that encourages to perform further research. If it will be confirmed, they could be proposed in a variety of bone diseases, in particular, when acute inflammation is associated to osteolytic processes and, eventually, in the prevention and treatment of periprosthetic osteolysis.

Animals↗

PubMed2005

Quantitative assessment of the response of osteoblast- and macrophage-like cells to particles of Ni-free Fe-base alloys.

In the present study, the effect of mechanically alloyed particles of new FeAlCr alloys developed for potential applications as surgical implants has been tested on osteoblast- and macrophage-like cells and compared to particles of the Ti6Al4V alloy, for which there is a good clinical experience. After microstructural characterisation of the particles, cells were cultured with particles for 24-48 h using three different concentrations of particles, and the response of cells was quantified by assessment of viability, proliferation, and morphology. Mineralisation by osteoblasts was verified after 21 days. The amount of aluminium and chromium ions in the culture medium of macrophages was measured by graphite furnace atomic absorption and phagocytosis of particles assessed by light microscopy. Viability and proliferation of osteoblast- and macrophage-like cells were substantially unaffected by the presence of particles of the new alloys, which were phagocytosed according to their size. Aluminium and chromium ions were released in the culture medium, but no direct correlation with the cell behaviour was found. In vitro mineralisation was achieved by osteoblasts in due time. The new alloys are well tolerated in in vitro systems, and, due to their chemical and mechanical characteristics, they are under development for surgical implants.

Alloys↗

PubMed2005

Systemic cross-linked N-terminal telopeptide and procollagen I C-terminal extension peptide as markers of bone turnover after total hip arthroplasty.

There is no diagnostic, non-invasive method for the early detection of loosening after total hip arthroplasty. In a pilot study, we have analysed two serum markers of bone remodelling, procollagen I C-terminal extension peptide (PICP) and cross-linked N-terminal telopeptide (NTx), as well as the diagnostic performance of NTx for the assessment of osteolysis. We recruited 21 patients with loosening (group I), 18 with a well-fixed prosthesis (group II) and 17 at the time of primary arthroplasty for osteoarthritis (OA) (group III). Internal normal reference ranges were obtained from 30 healthy subjects (group IV). The serum PICP level was found to be significantly lower in patients with OA and those with loosening, when compared with those with stable implants, while the NTx level was significantly increased only in the group with loosening, suggesting that collagen degradation depended on the altered bone turnover induced by the implant. This hypothesis was reinforced by the finding that the values in the pre-surgery patients and stable subjects were comparable with the reference range of younger healthy subjects.A high specificity and positive predictive value for NTx provided good diagnostic evidence of agreement between the test and the clinical and radiological evaluations. The NTx level could be used to indicate stability of the implant. However, further prospective, larger studies are necessary.

Adult↗

PubMed2004

Diagnosis of infection after total hip replacement.

Subclinical infection in patients with pain following total hip replacement (THR) is an underestimated condition that needs consideration because it mimics aseptic loosening, contributes to periprosthetic osteolysis, and necessitates proper treatment. We aimed to define the reliability of diagnostic parameters that are routinely used before revision surgery for the assessment of infection. A continuous series of 26 subjects who underwent THR revision surgery was considered, including 21 cases diagnosed as aseptic loosening (group A) and 5 hip revisions with a clinical diagnosis for infection (group B). Seven subjects at the time of the primary arthroplasty were used as negative controls (group C). Technetium-99m labeled hydroxymethylene diphosphonate [(99m)Tc-HDP]- and technetium-99m hexamethylpropyleneamine oxide [(99m)Tc-HMPAO)]-labeled granulocyte scintigraphy, histology of peri-implant tissues, laboratory tests for inflammation, and microbiology were performed. Scintigraphy was positive for loosening [positive (99m)Tc-HDP scan] but negative for infection [negative (99m)Tc-HMPAO-labeled granulocyte scan] in all group A patients, whereas in 11 cases (52%) a positive culture was unexpectedly obtained. Histology showed conflicting results: Polymorphonuclear cells (PMNs) were found only in 5 of 11 culture-positive patients, whereas in 2 cases the presence of PMNs did not correspond to a positive culture. In group B patients, both isotope scans and microbiology were found to be positive. All control subjects (group C) had negative cultures. In our opinion, smoldering infection could be present in a significant proportion of cases of failed hip implants currently diagnosed as "nonseptic." The inflammatory response to wear debris and the presence of superimposed, slowly growing bacteria could act synergically, both contributing to the pathogenesis of periprosthetic osteolysis.

Adult↗

PubMed2004

The influence of alumina and ultra-high molecular weight polyethylene particles on osteoblast-osteoclast cooperation.

Particle-induced macrophage activation, mainly by UHMWPE wear, has been recognized as the biological mechanism leading to periprosthetic bone resorption, which is responsible for the loosening of the total hip replacements (THR). Ceramic-on-ceramic implants have been advocated as a means of reducing wear products. Many studies investigated the effect of alumina (Al(2)O(3)) particles on monocytes/macrophages, but only limited information are available on their participation to bone turnover. An in vitro model was performed to investigate how Al(2)O(3) and UHMWPE particles may influence the osteoblast-osteoclast interaction: human osteoblasts (HOB) were obtained from trabecular bone, while osteoclasts were derived from peripheral blood mononuclear cells (PBMC) of healthy donors. The amount of IL6, TNF alpha, GM-CSF, and other factors acting on the bone turnover, i.e. the 'receptor activator of NF kappa B' ligand (RANKL) and osteoprotegerin (OPG), was detected in culture medium of particle-challenged HOB (HOB-CM). The Al(2)O(3) and UHMWPE particles did not affect either cell viability or TNF and GM-CSF release, while the increase in IL6 release seemed to be dependent on the particle concentration. UHMWPE increased the release of RANKL from HOB, while OPG and OPG-to-RANKL ratio were significantly inhibited. The ability of HOB-CM to promote osteoclastogenesis was tested via osteoblast/monocyte cooperation: after seven days of culture UHMWPE HOB-CM induced a large amount of multinucleated TRAP-positive giant cells, as well as significantly reduced the amount of IL6, GM-CSF and RANKL in the supernatant. With regard to the inductive effect on the osteoclastogenesis, our results show that the Al(2)O(3) wear debris are less active.

Aluminum Oxide↗

PubMed2004

Ability of restorative and fluoride releasing materials to prevent marginal dentine demineralization.

The study aimed to define the in vitro secondary caries inhibiting potential of restorative materials currently used in dental practice. Class V restorations were prepared in extracted human third molars and immersed in a demineralizing solution (lactic acid, pH 4.5) at 37 degrees C for 2 days to simulate secondary caries formation. The bonding and the restorative systems tested in the study were: Scotchbond 1+Z 250 (Group A), Scotchbond 1+F 2000 (Group B), ABF+APX (Group C), ABF+F2000 (Group D). Perimarginal dentine, immediately close to the margin of the restoration, and exposed dentine, at approximately 0.5 mm from the margins of the restoration, after exposure to the acid solution, were investigated; protected dentine, at approximately 4 mm from the margin in a varnish-covered area, was analysed as control. Polarized light microscopy and contact transverse microradiography (TMR) were employed. The output parameters were lesion shape and size (depth in microm) of the exposed dentine, dentine mineral volume%, and integrated mineral loss (Delta Z, in %volmicrom) of the lesions. Compomers (Groups B and D) showed a thinner demineralization of the outer lesions, a less demineralization along the perimarginal dentine (inner lesion) and more caries inhibition zones or CIZs (Delta Z positive values) compared to composites (Groups A and C). In conclusion, Groups B and D materials seemed to partially counteract the marginal demineralization induced by an acid solution and favourably influence the formation of CIZs along the restorations. On the contrary, composites did not show a protective effect, probably due to an insufficient marginal seal and the lack of fluoride release.

Absorptiometry, Photon↗

PubMed2003

Biologic effects of surface roughness and fluorhydroxyapatite coating on osteointegration in external fixation systems: an in vivo experimental study.

The concomitant influence of surface roughness and fluorhydroxyapatite (FHA) coating of titanium (Ti) implants on bone response was investigated. For this purpose, titanium screw-shaped implants with a lower degree (Y371) and a higher degree (TiPore300) of surface roughness, coated with FHA and uncoated, were transversally inserted into the diaphyses of sheep tibiae for 12 weeks. Four sheep received Y371 (group A) and Y371 + FHA (group B) screws and four sheep received TiPore300 (group C) and TiPore300 + FHA (group D) screws. For each type of material, the morphology and microstructure of implant-facing bone were evaluated. The host bone of each tibia was used as a control. In all groups the bone tissue did not reach a complete maturation. The higher degree of roughness, perhaps due to an excessive irregularity of the surface, induced the worst osteointegration: a fibrous tissue layer between screw and new bone tissue was often present. Nevertheless, as viewed by XRD, no crystallographic change of the apatite lattice was observed in any of the implants. In contrast, the microhardness value, an index of bone mineralization, was higher in the uncoated screws and decreased progressively in the following order: group C > group A > group B > group D. The association of plasma spraying with roughness treatment constitutes a complex system that seems to interfere with bone mineralization. A chemical change of the surface, perhaps with more Ti release or more coating degradation, could be responsible for such impairment. The authors emphasize the necessity for simultaneous evaluation of surface topography and chemistry as well as an improvement in plasma-spraying and post-processing techniques and in standard procedures for materials characterization.

Animals↗

PubMed2003

Ion release in stable hip arthroplasties using metal-on-metal articulating surfaces: a comparison between short- and medium-term results.

The use of metallic heads articulating with metallic cups could solve the problem of polyethylene (PE) wear in total hip replacement (THR) with metal-on-PE bearings. A conspicuous release of metal ions from new models of metal-on-metal bearings has been found in the short-term, but it is yet unclear whether the medium-term corrosion rate is high or, on the contrary, it becomes negligible, because of the continuous surface finishing. Our purpose was to compare the serum ion values (nanograms per milliliter) in 15 patients with metal-on-metal stable prosthesis (Group A), in the short-term (subgroup A(1); mean follow-up: 24 mo) and medium-term (subgroup A(2); mean follow-up: 52 mo), in order to determine whether the ion release decreased with time of implant. Chromium (Cr), cobalt (Co), molybdenum (Mo) and aluminum (Al) were analyzed. Twenty-two presurgical patients were used for comparison (Group B). The reference range was obtained from a population of 27 healthy subjects (Group C). Co and Cr levels in the medium-term (subgroup A(2)) were not decreased in comparison with the short-term values (subgroup A(1)) and were significantly higher (p < 0.001) than presurgical and reference values. Otherwise, Mo and Al concentrations were not significantly increased in comparison with reference values. In conclusion, despite the apparent advantage of metal-on-metal coupling, especially in younger patient populations, there is a major concern about the extent and duration of the relevant "internal" exposure to Cr and Co ions. This exposure should be carefully monitored, in order to clarify the biologic effects of ion dissemination and, consequently, to identify risks concerning long-term toxicity of metals.

Adult↗

PubMed2003

Biomechanical and histomorphometric investigations on two morphologically differing titanium surfaces with and without fluorohydroxyapatite coating: an experimental study in sheep tibiae.

The influence of fluorohydroxyapatite (FHA) coating and surface roughness of Ti6Al4V implants on bone response was investigated. Uncoated and FHA-coated screws with lower (LR and LR+FHA; Ra: 5.7+/-0.2 microm) and higher (HR and HR+FHA; Ra: 21.8+/-0.9 microm) surface roughness, were inserted into the diaphyses of 8 sheep tibiae. Twelve weeks after implantation, extraction torque and bone-to-implant contact were evaluated. The smoothest surfaces showed an improved extraction torque and significant differences were observed between LR and HR (-24.6%, p<0.0005), LR and HR+FHA (-30.7%, p<0.0005), LR+FHA and HR (-17.4%, p<0.005), and LR+FHA and HR+FHA (-24.0%, p<0.005). The bone-to-implant contact data paralleled the biomechanical data: the smoother the surface, the greater the bone-to-implant contact. Significant (p<0.0005) decreases in bone-to-implant contact were observed between LR+FHA and HR (-24.2%), and between LR+FHA and HR+FHA (-29.2%). The current findings suggest that LR surfaces significantly improve the osteointegration rate of implanted cortical screws independently of the FHA coating.

Animals↗

PubMed2003

Osteoblast growth and function in porous poly epsilon -caprolactone matrices for bone repair: a preliminary study.

Current methods for the replacement of skeletal tissue involve the use of autografts, allografts and, recently, synthetic substitutes, which provide a proper amount of material to repair large bone defects. Engineered bone seems a promising approach, but a number of variables have to be set prior to any clinical application. In this study, four different poly caprolactone-based polymers (PCL) were prepared and tested in vitro using osteoblast-like Saos-2 cells. Differences among three-dimensional polymers include porosity, addition of hydroxyapatite (HA) particles, and treatment with simulated body fluid. Biochemical parameters to assess cell/material interactions include viability, growth, alkaline phosphatase release, and mineralization of osteoblastic cells seeded onto three-dimensional samples, while their morphology was observed using light microscopy and SEM. Preliminary results show that the polymers, though degrading in the medium, have a positive interaction with cells, as they support cell growth and functions. In the short-term culture (3-7 days) of Saos-2 on polymers, little differences were found among PCL samples, with the presence of HA moderately improving the number of cells onto the surfaces. In the long term (3-4 weeks), it was found that the HA-added polymers obtained the best colonization by cells, and more mineral formation was observed after coating with SBF. It can be concluded that PCL is a promising material for three-dimensional scaffold for bone formation, and the presence of bone-like components improves osteoblast activity.

Biocompatible Materials↗

PubMed2002

Ion release in patients with metal-on-metal hip bearings in total joint replacement: a comparison with metal-on-polyethylene bearings.

Polyethylene (PE) wear has been shown to be a problem in long-term joint replacement using metal-on-PE bearing. The use of metallic heads articulating with metallic cups could solve this problem: success will be enhanced if wear and corrosion of the articulating surfaces are maintained at a low level. New models with metal-on-metal bearing have been proposed, to be used mainly for young subjects: such coupling seems to have a reduced release, but it is unclear yet if the medium-term corrosion rate is really negligible or, on the contrary, it is significantly higher than in the metal-on-PE bearing. Aim of our study was the comparison of ion release in the serum of two groups of patients who had the same type of stable cementless prosthesis, but different bearing: twenty-six patients with metal-on-metal (Group A) and fifteen patients with metal-on-PE bearing (Group B) were examined. The follow-up was 14-38 months for group A and 18-34 months for group B. The serum concentration of chromium (Cr), cobalt (Co) and molybdenum (Mo) was measured. Twenty-two patients before surgery were used for comparison (Group C). The reference values were obtained from a population of twenty-two healthy subjects (Group D). Our findings indicate that metal-on-metal bearings produce a significantly higher systemic release of cobalt and chromium (ng/ml) when compared with levels found in metal-on-PE, pre-surgery and reference groups. Such a high release should induce to improve the bearing materials or, at least, to study the biologic fate of metal ions and consequently their long-term effects. In such a way a risk-to-benefit ratio for the patient could be established.

Adult↗

PubMed2002

In vitro testing of the potential for orthopedic bone cements to cause apoptosis of osteoblast-like cells.

The purpose of this study was to investigate in vitro the apoptosis- and/or necrosis-inducing potential of polymethylmethacrylate (PMMA)-based bone cements for prosthetic surgery. Four bone cements widely used in orthopedics were tested as extracts onto osteoblast-like MG-63 cells and for comparison, HL-60 cells, which are remarkably sensitive to apoptotic stimuli. Neutral red uptake (NRU) was used to measure cell viability while Hoechst 33258 staining was used to detect DNA content. Apoptosis was characterized using a BrdU-based ELISA assay for DNA fragmentation and examined by fluorescence microscopy using acridine orange and propidium iodide staining of nuclei. The generation of reactive oxygen species (ROS), which could mediate apoptosis, was verified using dichlorofluorescein-diacetate (DCFH-DA) oxidation to DCF. After 24 h of challenge of the cells with the four cement extracts, the viability of either MG-63 or HL-60 cells was found to be unaltered, as recorded by NRU. Apoptotic cell death was induced by three cements in HL-60, whereas MG-63 cells were significantly affected by the four cements tested: the finding of DNA fragments both in the cytoplasm and supernatants of MG-63 after 24 h demonstrated that these cells underwent late-apoptosis secondary necrosis. Fluorescent staining of the nuclei confirmed the results obtained with the ELISA test. Oxygen free radicals were elicited by two cements in HL-60 cells, while MG-63 did not generate ROS in response to cements. This study helps to gain more insight into the mechanism of cell death induced by PMMA-based cements and suggests apoptosis of osteoblasts as a part of the tissue reaction around cemented prostheses.

Apoptosis↗

PubMed2002

Enamel microhardness after in vitro demineralization and role of different restorative materials.

This study aimed to evaluate the extension of enamel demineralization around the margin of restorations after immersion in cariogenic solution, in an attempt to define the role of new restorative materials in preventing secondary caries formation. For this purpose, enamel microhardness was measured. Twelve class V restorations in human extracted third molars were prepared in vitro and immersed in a demineralizing solution (lactic acid, pH 4.5) at 37 degrees C for 3 days to simulate the formation of secondary caries and its effect on the marginal integrity of composite restorations. The restorative systems tested in the study were Scotchbond 1 + Z 250 (group A), ABF + APX (group B), Fuji IX (group C), SE Bond + APX (group D), and Scotchbond 1 + F 2000 (group E). The microhardness was measured close to the margin of restoration (marginal exposed enamel), at 2.0 mm from the margin (exposed enamel), and at approximately 4 mm from the margin in a varnish-covered enamel area (protected enamel). Five measurements were made on each site at 20, 40, 60, 80, and 100 microm depth from the external enamel surface. Exposed enamel and marginal exposed enamel were greatly affected by the cariogenic solution, as confirmed by the high rate of demineralization. The marginal exposed enamel showed a higher rate of demineralization than the exposed enamel, as demonstrated by the lowest microhardness values. The materials that claimed fluoride release did not prevent any type of enamel marginal alteration. This study revealed that enamel close to the margin of restoration may be rapidly affected by secondary caries formation when immersed in a demineralizing-cariogenic solution and that fluoride-releasing materials are unable to reduce the marginal demineralization processes. These demineralization processes may be responsible for marginal secondary caries and for restoration failures.

Biomechanical Phenomena↗

PubMed2002

Gene expression of bone-associated cytokines in MG63 osteoblast-like cells incubated with acrylic bone cement extracts in minimum essential medium.

This study examined the effects of in vitro challenge with four polymerized acrylic bone cements (Sulfix-60, CMW 1, CMW 2, and CMW 3) on the expression of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), and transforming growth factor-beta1 (TGF-beta1) mRNAs in the osteoblast-like cell line MG63. The extracts of the cements in minimal essential medium (MEM) were tested following 1-h and 7-day curing. A semi-quantitative analysis of the cytokine-specific mRNAs was carried out by agarose gel densitometry and expression was compared with the GAPDH housekeeping gene. The ratio between cytokine gene expression and GAPDH expression was calculated. The mRNA specific for the bone-resorbing cytokines IL-1beta and IL-6 was low in basal conditions. IL-1beta mRNA increased only after incubation with the extract of CMW 1 following 1-h curing. The mRNA specific for the bone-resorbing cytokine IL-6 also increased after contact with CMW 1 at both curing times. Sulfix-60 and CMW 3 following 7-day curing, but not after 1 h, induced higher levels of IL-6 mRNA than the control. CMW 2 after 1-h curing constantly determined the expression of IL-6 mRNA, but at low levels. The mRNA specific for TGF-beta1 was also expressed by the MG63 osteoblast-like cells in basal conditions. The levels increased after contact with Sulfix-60 after 7-day curing and with CMW 1 after 1-h curing. CMW 2 after 7-day curing decreased TGF-beta1 mRNA. In conclusion, the highest expression of the cytokines IL-1beta, IL-6, and TGF-beta1 mRNA was determined by CMW 1. If the results are confirmed in vivo, the increased expression of the osteolytic cytokines induced by the bone cement might result in loosening of the prosthesis, even with all the restrictions of an in vitro study on continuous cell lines.

Bone Cements↗

PubMed2001

Evaluation of tissue-factor production by human endothelial cells incubated with three acrylic bone cements.

The effect of three methacrylate-based cements used for the fixation of joint prostheses on tissue-factor production by human umbilical vein endothelial cells was evaluated in vitro. The extracts in the culture medium of the cements were tested after 1-h and 7-day curing. The endothelial cells were incubated with the cement extracts for 4 h, and then the tissue factor was determined in cell lysates with both the recalcification time and enzyme immuno assay. The cements did not induce significant production of tissue factor and, therefore, did not activate the extrinsic pathway of coagulation within the limits of the mechanism considered.

Ascorbic Acid↗