Biomedical subjects

P Torricelli

Publications and source records attributed to P Torricelli.

At least 37 records · Page 2Linked to original sources

PubMed2004

In vitro models to test orthopedic biomaterials in view of their clinical application in osteoporotic bone.

The development of in vitro cell cultures, in association with in vivo experimentation, greatly improved the characterization of biomaterials for orthopedic devices before their clinical use. In recent years an increasing interest has arisen in the use of both pathological osteoblast cultures and animal models to perform in vitro and in vivo tests on biomaterial behavior. A growing number of prostheses, in fact, are implanted in osteoporotic patients, due to the increasing age of the population. Moreover, the presence of osteoporosis may affect bone-biomaterial osteointegration in these patients. The present paper is a literature review and, after a short description of in vitro studies for characterization of osteoblasts derived from osteoporotic bone, the results of in vitro studies on biomaterial biocompatibility and osteointegration rate in the presence of osteoporotic bone derived osteoblast cultures are reported. Pathological cell culture models are able to demonstrate the different behavior of osteoblasts in response to biomaterials, when comparing normal and pathological conditions.

Animals↗

PubMed2004

A biomimetic gelatin-calcium phosphate bone cement.

The interest in new bone substitutes is rapidly increasing in the field of orthopedic surgery. A variety of calcium phosphate bone cement has been developed and different additives have been used to improve their biocompatibility and bioactivity. Following a biomimetic strategy aimed at reproducing bone characteristics, this study investigates the biological properties of a new gelatin enriched calcium phosphate cement (GEL-CP) that exhibits improved mechanical properties with respect to cement prepared without gelatin (C-CP). Human osteoblast MG63 were cultured on the surfaces of GEL-CP and were compared to cells cultured on C-CP samples, and on polystyrene of plate culture as control (C). Cell attachment, proliferation and differentiation were evaluated up to 21 days. SEM revealed that osteoblasts grown on GEL-CP showed a normal morphology and biological tests demonstrated very good rate of proliferation and viability in every experimental time. The presence of gelatin stimulated alkaline phosphatase activity, collagen and transforming growth factor 31 production. The data indicate that the new cement GEL-CP favors osteoblast proliferation, activation of their metabolism and differentiation. The remarkable improvement of the setting properties of the calcium phosphate cement due to the presence of gelatin suggest that the biomimetic composite material could be successfully applied as bone substitute.

Alkaline Phosphatase↗

PubMed2004

Current trends in the enhancement of biomaterial osteointegration: biophysical stimulation.

To enhance bone implant osteointegration, many strategies for improving biomaterial properties have been developed which include optimization of implant material, implant design, surface morphology and osteogenetic coatings. Other methods that have been attempted to enhance endogenous bone healing around biomaterials are different forms of biophysical stimulations such as pulsed electromagnetic fields (PEMFs) and low intensity pulsed ultrasounds (LIPUS), which were initially developed to accelerate fracture healing. To aid in the use of adjuvant biophysical therapies in the management of bone-implant osteointegration, the present authors reviewed experimental and clinical studies published in the literature over the last 20 years on the combined use of biomaterials and PEMFs or LIPUS, and summarized the methodology, and the possible mechanism of action and effectiveness of the different biophysical stimulations for the enhancement of bone healing processes around bone implanted biomaterials.

Animals↗

PubMed2004

Natural and synthetic polyesters for musculoskeletal tissue repair: experimental in vitro and in vivo evaluations.

Two natural Biopol polyesters, containing 8% (D400G) and 12% (D600G) of hydroxyvalerate component, and a synthetic polyester based on 1,4 cyclohexanediol [Poly(cyclohexyl-sebacate)--PCS] were studied to investigate their in vitro and in vivo behavior for application in musculoskeletal tissue repair. The polyesters were placed in direct contact with L929 fibroblasts and cell proliferation (WST-1), cytotoxic effect (LDH), synthetic activity (total proteins) and cytokine production (IL-1beta, IL-6, TNFalpha) were assessed after an incubation period of 72 hours and 7 days. Then, 12 Sprague-Dawley rats underwent dorsal subcutaneous implants of tested polyesters under general anesthesia. After 1 and 4 weeks from surgery, the animals were pharmacologically euthanized and the implants retrieved with surrounding tissue for histologic and histomorphometric investigations. In vitro results showed that D600G behaved a little worse in comparison to other tested polyesters in terms of cell proliferation and TNFa at 7 days. PCS presented the lowest total protein value at 7 days. In vivo results indicated that PCS implants produced a higher (p < 0.01) extent of inflammatory tissue in comparison to D600G at 1 week and to D400G at 4 weeks, and the lowest vascular densities at both experimental times. D400G seems to be the most suitable material for biomedical application when tested in fibroblast cultures and in the subcutaneous tissue of rats.

Animals↗

PubMed2004

Nanocrystalline hydroxyapatite-polyaspartate composites.

The direct synthesis of hydroxyapatite-poly-L-aspartic acid (HA-PASP) nanocrystals has been carried out in presence of increasing amounts of PASP in solution up to 56 mmol/l. WAXS, TEM, TGA, IR and chemical analyses were used to characterize the structure, morphology and composition of the products. PASP is quantitatively incorporated into HA crystals, provoking a reduction of the coherent length of the crystalline domains. Furthermore, composite crystals display a greater length/width ratio with respect to the control HA crystals, and show a remarkable trend towards aggregation. The broadening of the X-ray diffraction reflections indicate a reduction of the coherent length along the long dimension 002 and the cross section 310 of the apatite crystals. The comparison between the morphological and structural data allows to suggest a specific interaction between PASP and HA structure.

Biocompatible Materials↗

PubMed2003

A new austenitic stainless steel with negligible nickel content: an in vitro and in vivo comparative investigation.

New nickel (Ni)-reduced stainless-steel metals have recently been developed to avoid sensitivity to Ni. In the present study, an austenitic Ni-reduced SSt named P558 (P558, Böhler, Milan, Italy) was studied in vitro on primary osteoblasts and in vivo after bone implantation in the sheep tibia, and was compared to ISO 5832-9 SSt (SSt) and Ti6Al4V. Cells were cultured directly on P558 and Ti6Al4V. Cells cultured on polystyrene were used as controls. Osteoblast proliferation, viability and synthetic activity were evaluated at 72 h by assaying WST1, alkaline phosphatase activity (ALP), nitric oxide, pro-collagen I (PICP), osteocalcin (OC), transforming growth factor-beta1 (TGFbeta-1) and interleukin-6 (IL-6) after 1.25(OH)2D3 stimulation. Under general anaesthesia, four sheep were submitted for bilateral tibial implantation of P558, SSt and Ti6Al4V rods. In vitro results demonstrated that the effect of P558 on osteoblast viability, PICP, TGF beta-1, tumor necrosis factor-alpha production did not significantly differ from that exerted by Ti6Al4V and controls. Furthermore, P558 enhanced osteoblast differentiation, as confirmed by ALP and OC levels, and reduced IL-6 production. At 26 weeks, the bone-to-implant contact was higher in P558 than in SSt (28%, p<0.005) and Ti6Al4V (4%, p<0.05), and was higher in Ti6Al4V than in SSt (22%, p<0.005). The tested materials did not affect bone microhardness in pre-existing host bone as evidenced by the measurements taken at 1000 microm from the bone-biomaterial interface (F=1.89, ns). At the bone-biomaterial interface the lowest HV value was found for SSt, whereas no differences in HV were observed between materials (F=1.55, ns). The current findings demonstrate P558 biocompatibility both in vitro and in vivo, and osteointegration processes are shown to be significantly improved by P558 as compared to the other materials tested.

Alloys↗

PubMed2003

Comparative interspecies investigation on osteoblast cultures: data on cell viability and synthetic activity.

The aim of the present study was to evaluate and compare the most common parameters that characterize the expression of primary osteoblast cultures from different origin (human, rat, sheep), and of the human osteosarcoma cell line MG-63 before and after stimulation with vitamin 1,25(OH)(2)D(3). Cell viability was quite similar for primary osteoblast cultures (MTT: 1.64-2.11 OD); a significant (P < 0.005) difference was found between sheep osteoblasts and MG-63 (DeltaMTT: 0.52 +/- 0.20 OD). Osteocalcin synthesis ranged from 15.18 to 27.00 pg/ml in primary osteoblast cultures, while it was significantly (P < 0.01) lower in MG-63 (OC: 6.67 +/- 0.52 pg/ml) when compared with primary human osteoblasts. Alkaline phosphatase, C-terminal procollagen type I, and interleukin-6 were significantly (P < 0.005) lower in rat osteoblasts when compared with primary human osteoblasts, and similarly transforming growth factor-beta1 was significantly (P < 0.05) lower in rat and sheep osteoblasts when compared with primary human osteoblasts and MG-63. Nitric oxide synthesis did not show any significant difference either before or after vitamin 1,25(OH)(2)D(3) stimulation. In conclusion, the current findings confirm the presence of interspecies differences between the selected osteoblast lineages before and after stimulation with vitamin 1,25(OH)(2)D(3). Above all, the culture of sheep osteoblasts was seen to behave more similarly to that of primary human cells, mainly in terms of cell viability, osteocalcin, interleukin-6 and transforming growth factor-beta1 production.

Animals↗

PubMed2003

Exploring the damage limitation possibilities of mineral fibres for future integrated solutions: an in vitro study.

Owing to their possible carcinogenic effect, asbestos and other silica derivatives have been identified as priority substances for risk reduction and prevention of pollution. Neutralisation procedures have thus become a topical research subject in many European and American countries. In the present study, silica derivatives (asbestos-containing and asbestos substitutes like slag wool, rock wool, cement asbestos) were fully impregnated with an epoxy resin according to the procedure used for the in situ impregnation with viscous polymeric media, which penetrate and cement the fibres in place and reduce the risk of their dispersion in air. Untreated and treated samples were used to investigate their in vitro interaction with a human continuous epithelial cell line (NCTC 2544 keratinocytes) and test the resin's efficiency in passivating the surface activity of the fibrous particulate. SEM and morpho-quantitative data evidenced that impregnation with the epoxy resin modifies the mineral fibres' bioactivity (reduction of cell adhesion and decreased spread/round cell ratio) and demonstrated the value of in vitro cell testing after passivation as a risk-assessment procedure. These tests could be used for the rapid determination of the level of passivation of new synthetic mineral fibrous materials subjected to resin impregnation.

Air Pollutants, Occupational↗

PubMed2003

In vitro behaviour of osteoblasts cultured on orthopaedic biomaterials with different surface roughness, uncoated and fluorohydroxyapatite-coated, relative to the in vivo osteointegration rate.

The effects of two surfaces with different roughness (Low Roughness, LR: Ra: 5.6-5.9 microm; High Roughness, HR: Ra: 21.5-22.5 microm), uncoated and fluorohydroxyapatite(FHA)-coated, were investigated in MG-63 osteoblasts. At 72 hours, cells proliferated on biomaterials more slowly than in the control group (p < 0.0001), the proliferation rate was higher on FHA-coated LR than uncoated HR (p = 0.037). Collagen-I production was positively affected by the LR surface (p = 0.001) as compared to controls, while it was significantly lower (p = 0.0001) in the HR surfaces. Compared to controls, LR and HR surfaces led to enhanced production of TGF-beta1, further improved by FHA (FHA-coated LR: p = 0.007; FHA-coated HR p < 0.0001 respectively). ALP, OC, IL-6 and TNF-alpha levels were not significantly different from the controls. Results suggest that collagen-I production could be useful in predicting the in vivo osteointegration rate of biocompatible biomaterials observed in previous studies.

Alkaline Phosphatase↗

PubMed2003

In vitro biocompatibility of titanium oxide for prosthetic devices nanostructured by low pressure metal-organic chemical vapor deposition.

Metal-Organic Chemical Vapor Deposition (MOCVD) has recently been proposed to coat orthopedic and dental prostheses with metal nanostructured oxide films through the decomposition of oxygenated compounds (single-source precursors) or the reaction of oxygen-free metal compounds with oxygenating agents. The present study was carried out to assess the in vitro biocompatibility in terms of cell proliferation and activation, of commercially pure Ti (control material: TI/MA) coated with nanostructured TiO2 film by MOCVD (Ti/MOCVD) using osteoblast-like cell cultures (MG-63). Evaluations were performed at 3, 7 and 14 days. Cell proliferation showed a similar trend for Ti/MA and TilMOCVD compared to polystyrene; cell number increased with time from seeding to day 7 (p < 0.005), and then decreased progressively until day 14 (ranging from -14% to -47%). The ALP level and OC production showed no significant differences between Ti/MOCVD and Ti/MA at each experimental time. Significantly higher ALP levels were found in Ti/MA at 3 days and in Ti/MOCVD at 7 and 14 days when compared to the polystyrene group. OC production decreased over time and the highest values were observed at 3 days, when it was significantly higher in the Ti/MA than in the polystyrene group (50%, p < 0.05). CICP synthesis was positively affected by the presence of Ti/MOCVD and was higher in Ti/MOCVD than in the polystyrene group. No significant differences were found between Ti/MOCVD and Ti/MA in terms of IL-6 and TGF-beta1 synthesis at any experimental time. In conclusion, the current findings demonstrate that the nanostructured TiO2 coating positively affects the osteoblast-like cell behavior in terms of cell proliferation and activity, thus confirming its high level of in vitro biocompatibility in accordance with expectations.

Biocompatible Materials↗

PubMed2003

Biomaterials in orthopedic surgery: effects of a nickel-reduced stainless steel on in vitro proliferation and activation of human osteoblasts.

A new austenitic stainless steel compound, P558, has been widely recognized to have good mechanical properties, excellent potential for corrosion resistance and negligible nickel ion release, making it a promising substitute for more expensive metallic prostheses with limited machinable features. The effect of P558 was studied in vitro and human osteoblast- like cells (MG63) were cultured directly on P558, Ti6Al4V alloy (Ti), and polystyrene (Control) for 72 hours. Osteoblast functions were evaluated by assaying cell proliferation and synthetic activity after 1.25(OH)2D3 stimulation. Results demonstrated that growth of MG63 on P558 was not negatively affected when compared to the Ti and Control groups and showed no alteration in the production of ALP, NO and PICP. Moreover, IL-6 was lower, whereas OC and TGFbeta1 were significantly higher. SEM images revealed that cells proliferated and differentiated on P558 without any alteration in their morphology. The current findings have demonstrated that P558 promotes osteoblast proliferation, activation and differentiation without negative effects and, thus, its good biocompatibility when used for orthopedic application.

Alloys↗

PubMed2003

Tailoring biomaterial compatibility: in vivo tissue response versus in vitro cell behavior.

Biocompatibility relies essentially on surface phenomena, represented by cell-cell, cell-material and material (polymer)-protein interactions. An in vivo and in vitro experimental investigation was carried out on the biomaterials of two different classes with a good potential for in situ utilisation. Non-resorbable (Polypyrrole, Polyaniline, Polyimide) and resorbable (PLLA-PDXO-PLLA) materials for tissue engineering were studied for their overall tissue tolerance and cellular interactions. These non-resorbable polymers conceived for biosensor applications and implantable drug-delivery systems are intrinsically conductive. The PLLA-PDXO-PLLA triblock copolymer showed interesting tensile properties for bone and cartilage tissue engineering due to the presence of 1,5-dioxepan-2-one. In vitro and in vivo parallel studies showed an interesting correspondence: a) the cells in contact with the resorbable material that appeared to be capable of migratory-regenerative aspects in vitro exhibited good compatibility in vivo; whereas b) the non-resorbable materials, which are designed to remain in situ in vivo, were seen to have the potential to represent an adverse factor (inflammation, fibrotic reactions) that correlated with some aspects of cell behaviour in vitro.

Absorbable Implants↗

PubMed2002

Improvement in zirconia osseointegration by means of a biological glass coating: An in vitro and in vivo investigation.

The biocompatibility and osseointegration of zirconia (ZrO(2)), either coated with RKKP bioglazeor uncoated, were evaluated in vitro and in vivo. The in vitro test was performed in human osteoblasts, whereas maximal sensitization was performed in 23 Dunkin Hurtley guinea pigs. RKKP bioglaze-coated and uncoated (controls) ZrO(2) cylinders were implanted in the distal femoral epiphyses of 14 Sprague-Dawley rats under general anesthesia, and animals were sacrificed at 30 and 60 days. Lactate dehydrogenase, alkaline phosphatase, and Thiazolyl Blue (MTT) were tested in vitro. A graded score was used for evaluating the results of the sensitization test. Histomorphometry and microhardness testing were performed to quantify the osseointegration rate, as well as bone quality around the implants. Neither in vitro cytotoxicity nor sensitization were observed. Histomorphometry demonstrated that at 30 days, the affinity index was significantly higher in coated implants than in uncoated ones (p < 0.05); at 60 days, the behavior of coated implants was better than that of uncoated ones, but differences were not significant. Significant increases in bone microhardness were found at 1000 microm from the interface area for both uncoated (p < 0.0005) and RKKP bioglaze-coated (p < 0.0005) ZrO(2), and also within 200 microm from the interface (p = 0.014) but only for coated ZrO(2.) These results suggest that RKKP bioglaze-coated ZrO(2) permits biocompatible devices with improved osseointegration properties to be manufactured.

Animals↗

PubMed2002

Laser stimulation on bone defect healing: an in vitro study.

The aim of this in vitro study was to evaluate whether low-power laser (LPL) stimulation can accelerate bone healing. Bone defects of a standard area were created in the distal epiphysis of 12 femora explanted from six rats, and they were cultured in BGJb medium for 21 days. Six defects were treated daily with Ga-Al-As, 780 nm LPL for 10 consecutive days (lased group, LG), while the remainder were sham-treated (control group, CG). Alkaline phosphatase/total protein (ALP/TP), calcium (Ca), and nitric oxide (NO) were tested on days 7, 14 and 21 to monitor the metabolism of cultured bone. The percentage of healing of the defect area was determined by histomorphometric analysis. After 21 days significant increases were observed in ALP/TP in LG versus CG (p<0.001), in NO in the LG versus CG ( p<0.0005) and in Ca in CG versus LG ( p<0.001). The healing rate of the defect area in the LG was higher than in the CG ( p=0.007). These in vitro results suggest that Ga-Al-As LPL treatment may play a positive role in bone defect healing.

Alkaline Phosphatase↗

PubMed2002

Hyaluronic acid hydrogel in the treatment of osteoarthritis.

In order to overcome the problem of rapid clearance of the polysaccharide hyaluronic acid (Hyal) in the treatment of osteoarthritis (OA), a 50% cross-linked Hyal hydrogel (Hyal 50%) was synthesised. The 50% refers to the amount of COOH groups of the polysaccharide involved in the cross-linking reaction. i.e. 50% of the total amount. The rheological behaviour of the Hyal 50% hydrogel, and in particular the possibility to inject it through a needle, was studied. The results obtained demonstrated that the hydrogel injected through the needle still behaved like a gel, although it showed a reduction of the dynamic moduli. The most appropriate sterilisation technique for this kind of hydrogel was also evaluated. Liophilised Hyal 50% samples were sterilised by steam, Ethylene Oxide (EtO) and gamma-rays. EtO and gamma-rays did not modify the characteristics of the hydrogel in terms of swellability and morphology. Lastly, the in vivo effect of Hyal 50% hydrogel in the treatment of chondral defect in rabbit knee was also studied. The results obtained showed the Hyal 50% injections improved chondrocytes density and matrix appearance. Furthermore, the permanence in situ of the hydrogel was longer than that of the linear Hyal.

3T3 Cells↗

PubMed2002

L-arginine and L-lysine stimulation on cultured human osteoblasts.

Essential amino acids, such as L-Arginine (Arg) and L-Lysine (Lys), are involved in bone metabolism and growth. Our previous studies analyzed the effect of these amino acids on rat osteoblast cultures and in experimental animals. In this study, we evaluated the effect of L-Arg and L-Lys on cultured human osteoblasts. Primary human osteoblast cultures were divided into four groups: the Arg Group received 0.625 mg/ml per day of Arg, the Lys Group 0.587 mg/ml per day of Lys, the Arg-Lys Group received both amino acids, whereas the Control Group was sham-treated. After 7 days, the following parameters were tested in all groups: alkaline phosphatase (ALP), nitric oxide (NO), calcium (Ca), phosphorus (P), osteocalcin (OC), type I collagen (PICP), interleukin-6 (IL-6), transforming growth factor-beta 1 (TGF-beta 1) on culture supernatant, platelet derived growth factor (PDGF), insulin-like growth factor-I (IGF-I), and MTT proliferation test on cells. Arg administration significantly increased ALP, NO, PICP and IGF-I production and reduced the level of IL-6. Lys administration over the same time interval mainly affected cell proliferation, as evidenced by the MTT test and immunostaining for PDGF. The same positive effects evidenced by the single administrations of the two amino acids resulted from their simultaneous administration. However, synergism could be demonstrated only for the decrease in the level of IL-6. Arg and Lys show a positive effect on human osteoblasts, which is related partly to the production of those factors required for matrix synthesis, and partly to the direct or mediated activation of cell proliferation.

Arginine↗

PubMed2002

In vitro response of primary rat osteoblasts to titania/hydroxyapatite coatings compared with transformed human osteoblast-like cells.

The biocompatibility of titania/hydroxyapatite (TiO(2)HA) composite coatings, at different ratio obtained by sol-gel process, was investigated studying the behavior of primary cultures of rat osteoblastic cells, isolated by femoral trabecular bone tissue. Moreover, the results have been compared with the response of human osteoblast-like MG63 cell line. Cytotoxicity of coatings was assessed by lactate dehydrogenase activity (LDH). The cellular behavior was analyzed by the cell proliferation (MTT test), cell morphology (SEM) and the biochemical markers evaluation of osteoblastic phenotype, such as alkaline phosphatase activity (ALP) and osteocalcin production. The results showed that TiO(2)/HA coatings have no toxic effects and seemed to be a good support for cell adhesion and proliferation. Moreover, these materials allowed the differentiation of osteoblasts, stimulating the expression of alkaline phosphatase activity. The responses of the primary rat osteoblasts and human osteoblast-like MG63 cell line grown onto these coatings were similar in terms of proliferation and ALP activity. Differences were found considering the osteocalcin production. The results show that these coatings, thanks to their chemical composition and the deposition technique, are very promising for the potential orthopedic and dental applications.

Journal Article↗

PubMed2001

Biological glass coating on ceramic materials: in vitro evaluation using primary osteoblast cultures from healthy and osteopenic rat bone.

ZrO2 and Al2O3 substrates were successfully coated by a double layer of a silica-based glass named RKKP, using a low-cost firing technique. RKKP is a glass well known for its bioactivity; therefore, a RKKP coating on Al2O3 or ZrO2, allows to combine the excellent mechanical properties of these strong ceramic substrates with its bioactivity. ZrO2 samples were easily coated using a double layer of RKKP by a simple enamelling technique. To accommodate the thermal expansion coefficient mismatch between Al2O3 and RK K P, this substrate was coated using a multilayered composite approach. All of the coatings were characterised from a morphological and compositional point of view, and an extensive biological evaluation was performed using fresh rat osteoblasts. Osteoblast primary cultures were derived from the trabecular bone of femoral condyles harvested from intact (NB) and osteopenic (OB) rats. After characterisation of their phenotype, osteoblasts were seeded on material samples of ZrO2 or Al2O3 coated with RKKP, and cultured for 7 days. Cell proliferation (MTT test) and cell differentiation (alkaline phosphatase activity) were evaluated at the end of the experiment, to assess osteoblast behaviour in the presence of biomaterials and determine if the results were related to the host bone quality. Results of both materials showed a good level of biocompatibility. In particular, MTT significant higher values were detected in NB cultures on ZrO2-RKKP samples; ALP activity significantly increased in NB cultures on Al2O3-RKKP and in OB cultures on both coated samples.

Aluminum Oxide↗