Biomimetic approach for an articular cartilage patch: Combination of decellularized cartilage matrix and silk-elastin-like-protein (SELP) hydrogel.

Articular cartilage degradation due to injury, disease and aging is a common clinical issue as current regenerative therapies are unable to fully replicate the complex microenvironment of the native tissue which, being avascular, is featured by very low ability to self-regenerate. The extracellular matrix (ECM), constituting almost 90% of the entire tissue, plays a critical role in its function and resistance to compressive forces. In this context, the current tissue engineering strategies are only partially effective in restoring the biology and function of the native tissue. A main issue in tissue regeneration is treatment failure due to scarce integration of the engineered construct, often following a gradual detachment of the graft. In this scenario, we aimed to create an adhesive patch able to adequately support cartilage regeneration as a promising tool for the treatment of cartilage injuries and diseases. For this, we produced an engineered construct composed of decellularized ECM (dECM) obtained from horse joint cartilage, to support tissue regeneration, coupled with a Silk-Elastin-Like Proteins (SELP) hydrogel, which acts as a biological glue, to guarantee an adequate adherence to the host tissue. Following the production of the two biomaterials we characterized them by assessing: 1) dECM morphological, chemical, and ultrastructural features along with its capability to support chondrocyte proliferation, specific marker expression and ECM synthesis; 2) SELP microarchitecture, cytocompatibility and mechanical properties. Our results demonstrated that both materials hold unique properties suitable to be exploited to produce a tailored microenvironment to support cell growth and differentiation providing a proof of concept concerning the in vitro biological and mechanical efficacy of the construct. The SELP hydrogel displayed a very interesting physical behavior due to its high degree of resistance to mechanical stress, which is generally associated with physiological mechanical load during locomotion. Intriguingly, the shear-thinning behavior of the hydrogel may also make it suitable to be applied and spread over non-homogeneous surfaces, therefore, we hypothesize that the hybrid biomaterial proposed may be a real asset in the treatment of cartilage defects and injuries.

Expression and function of the stromal cell-derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) in the swine ovarian follicle.

The most characterized stromal cell-derived factor-1 (SDF-1) variants are the isoform α, which is the predominant one but undergoes rapid proteolysis, and the ß isoform, which is more resistant. Through the interaction with a specific chemokine receptor called CXCR4, SDF-1 is able to regulate different physiological processes. The aim of this study was to verify the expression and potential functional role of SDF-1 and CXCR4 in the porcine ovary. Firstly, the expression of SDF-1 and its receptor in different ovarian districts was verified for the first time. Thereafter, the effect of SDF-1 ß isoform (51-72) fragment on functional parameters, such as proliferation, metabolic activity, redox status, nitric oxide production, and steroidogenic activity, was assessed on granulosa cells collected from follicles. In addition, the potential effect of this protein in vascular events was verified through investigations on porcine aortic (AOC) endothelial cells, such as the production of nitric oxide and viability tests. The proliferation and metabolic activity were not affected by treatment with the cytokine. As regard to steroidogenesis, the peptide stimulated both estrogen (P = 0.049) and progesterone production (P = 0.039). Redox status was affected by the examined substance since superoxide anion was inhibited (P = 0.001), while antioxidant power (P = 0.034), as well as nitric oxide generation, were stimulated (P = 0.034). Tests performed on AOCs showed significant stimulation of nitric oxide production (P = 0.004) by the examined peptide, while cell viability was unaffected. Therefore, the potential role of cytokine in the mechanisms involved in the regulation of follicular function can be hypothesized.

Orexin A in swine corpus luteum.

Orexin A (OXA) is a hypothalamic neuropeptide which acts on 2 known G-protein-coupled receptors. It has been demonstrated that OXA is a central molecular link between food intake and reproduction. More recently, its peripheral role has been investigated, and we demonstrated its involvement in regulating ovarian follicle function. The present study was undertaken to explore a potential physiological role of orexin system in swine corpus luteum, a transient ovarian endocrine organ. Our aim was, first, to analyze the localization and eventual colocalization of OXA and its 2 receptors within the different cell types composing the corpus luteum structure. Second, we wanted to explore the effects of OXA on isolated luteal cells, and finally to verify a potential involvement of OXA in angiogenesis, a crucial event in corpus luteum development. Our data demonstrate the local expression of OXA and its receptors in swine corpus luteum. Luteal cell functions were affected by treatment with OXA. In particular, progesterone production was inhibited (P < 0.05) and nonenzymatic scavenging activity was increased (P < 0.05). Moreover, OXA inhibited (P < 0.05) new vessel growth. Our results suggest that OXA could act locally to play a role in corpus luteum demise.

Enhancement of peri-implant bone osteogenic activity induced by a peptidomimetic functionalization of titanium.

Osteoblast cell adhesion to the extracellular matrix is established through two main pathways: one is mediated by the binding between integrin and a minimal adhesion sequence (RGD) on the extracellular protein, the other is based on the interactions between transmembrane proteoglycans and heparin-binding sequences found in many matrix proteins. The aim of this study is the evaluation in an in vivo endosseous implant model of the early osteogenic response of the peri-implant bone to a biomimetic titanium surface functionalized with the retro-inverso 2DHVP peptide, an analogue of Vitronectin heparin binding site. The experimental plan is based on a bilateral study design of Control and 2DHVP implants inserted respectively in the right and left femur distal metaphysis of adult male Wistar rats (n=16) weighing about 300grams and evaluated after 15days. Fluorochromic bone vital markers were given in a specific time frame, in order to monitor the dynamic of new bone deposition. The effect inducted by the peptidomimetic coating on the surrounding bone were qualitatively and quantitatively evaluated by means of static and dynamic histomorphometric analyses performed within three concentric and subsequent circular Regions of Interest (ROI) of equivalent thickness (220µm), ROI1 adjacent to the interface, ROI2, the middle, and ROI3 the farthest. The data indicated that these functionalized implants stimulated a higher bone apposition rate (p<0,01) and larger and rapid osteoblast activation in terms of mineralizing surface within ROI1 compared to the control (p<0,01). These higher osteoblast recruitment and activation leads to a greater bone-to-implant contact reached for DHVP samples (p<0,5). This represents an initial stimulus of the osteogenic activity that might results in a faster and better osteointegration process.

Degradation pattern of a porcine collagen membrane in an in vivo model of guided bone regeneration.

BACKGROUND AND OBJECTIVE: Although collagen membranes have been clinically applied for guided tissue/bone regeneration for more than 30 years, their in vivo degradation pattern has never been fully clarified. A better understanding of the different stages of in vivo degradation of collagen membranes is extremely important, considering that the biology of bone regeneration requires the presence of a stable and cell/tissue-occlusive barrier during the healing stages in order to ensure a predictable result. Therefore, the aim of this study was to investigate the degradation pattern of a porcine non-cross-linked collagen membrane in an in vivo model of guided bone regeneration (GBR). MATERIAL AND METHODS: Decalcified and paraffin-embedded specimens from calvarial defects of 18, 10-month-old Wistar rats were used. The defects were treated with a double layer of collagen membrane and a deproteinized bovine bone mineral particulate graft. At 7, 14 and 30 days of healing, qualitative evaluation with scanning electron microscopy and atomic force microscopy, and histomorphometric measurements were performed. Markers of collagenase activity and bone formation were investigated using an immunofluorescence technique. RESULTS: A significant reduction of membrane thickness was observed from 7 to 30 days of healing, which was associated with progressive loss of collagen alignment, increased collagen remodeling and progressive invasion of woven bone inside the membranes. A limited inflammatory infiltrate was observed at all time points of healing. CONCLUSION: The collagen membrane investigated was biocompatible and able to promote bone regeneration. However, pronounced signs of degradation were observed starting from day 30. Since successful regeneration is obtained only when cell occlusion and space maintenance exist for the healing time needed by the bone progenitor cells to repopulate the defect, the suitability of collagen membranes in cases where long-lasting barriers are needed needs to be further reviewed.

Orexin system in swine ovarian follicles.

Successful reproduction is strictly linked to metabolic cues. The orexins are a family of hypothalamic neurohormones, well known for their key role in the control of food intake and the involvement in several aspects of the reproductive process. The biological actions of both orexins are carried out through binding to the related Orexin 1 (OX1R) and Orexin 2 (OX2R) G-protein-coupled receptors. The purpose of this study was to investigate the presence of orexin system components in the porcine ovaries, to contribute to expand the knowledge about their pleiotropic role. First, we investigated the localization of orexin A (OXA) and its receptors by immunochemistry in different ovarian districts. Thereafter, we evaluated the expression of the prepro-orexin (PPO) gene and OXA effects on granulosa cell functions. Immunohistochemical study revealed the presence of orexinergic system components in porcine ovarian follicles. Moreover, our data show the expression of PPO messenger RNA in swine ovarian follicles >5 mm. In addition, OXA influences proliferation (P < 0.05), steroidogenic activity (P < 0.05), and redox status of granulosa cells (P < 0.05). Therefore, we hypothesize that OXA could exert a local physiological role in swine ovarian follicles even if further studies are required to deeply define the function of this pleiotropic system.

Stanozolol-soaked grafts enhance new bone formation in rat calvarial critical-size defects.

Androgen hormones play a significant role in regulating bone morphogenesis and in maintaining bone homeostasis throughout life. This study aimed to investigate the local effects of the non-aromatizable androgen stanozolol (ST) on bone regeneration in rats. Bilateral critical-size defects were created in the parietal bone of 26 male Wistar rats: the defect on one side was filled with a deproteinized bovine bone scaffold (DBB) soaked in ST solution (test) and the contralateral with DBB alone (control). Samples were collected at one month and three months. Histomorphometry revealed a significantly higher new bone formation (NB) (24.41% ± 4.14% versus 15.01% ± 2.43%, p < 0.05) and mineral apposition rate (MAR) (9.20 µm/day ± 0.37 versus 6.50 µm/day ± 1.09, p < 0.05) in the test versus control group at one month. Accordingly, real time-polymerase chain reaction revealed a consistently higher Runx2 expression in test samples (fold change test/control: 4.50 ± 1.17, p ≤ 0.05). No morphometrical differences between groups were detected at three months (p > 0.05). However, test samples were characterized by an increase in blood capillary density from one month (11.43 n mm-2 ± 2.01) to three months (28.26 n mm-2 ± 5.62), providing evidence of a vital remodeling tissue. Control samples presented a decrease of anti-Osterix (SP7)/anti-osteocalcin (BGLAP) (3.9 n mm-2 ± 0.32 versus 1.01 n mm-2 ± 0.20) and alkaline phosphatase (ALP) (12.14 n mm-2 ± 6.29 versus 6.29 n mm-2 ± 2.73) immunohistochemical-positive elements, which was suggestive of a stabilized healing phase. Based on these observations, local ST administration boosted bone regeneration in rat calvarial critical-size defects at one month. This study showed the potential of local steroid delivery in bone regeneration.

Effect of the supplementation with a blend containing short and medium chain fatty acid monoglycerides in milk replacer on rumen papillae development in weaning calves.

Feeding of neonates with artificial milk formulas is a popular trend toward early weaning of newborn dairy calves. These milk replacers (MR) should accelerate the rumen development, determining early solid feed intake and leading to better performances in cattle. Previous research demonstrated that sodium butyrate supplementation in MR can affect both small intestine and rumen development. Also acetate and propionate showed similar properties, while only a few studies indicate some potential benefit of monoglycerides on gut functions. The present study is aimed to determine the effect of the supplementation of a blend containing short and medium chain fatty acids monoglycerides (SMCFA) in milk replacer on rumen papillae development and growth performances in weaning calves. Twenty bull calves (about 2 weeks old, weighing around 43kg) were randomly allocated into two groups: control (C) and treated (T). Besides MR and starter diet, the latter offered at libitum, T calves received 0.2% SMCFA in MR. Animals were slaughtered after 56 days from the beginning of the trial. No difference was found between groups either in growth performances or in mean number of papillae/cm(2) of mucosa, total surface of papillae (mm(2))/cm(2) of mucosa or papillary size. In both groups, the morphology of the rumen epithelium was typical of parakeratosis. The cells of the stratum spinosum were directly transformed into swollen, ovoid, still nucleated keratinocytes, particularly at the papillary tip, probably as a result of unphysiological osmolarities caused by high concentrate intake. Degenerated squamous horn cells covered the "balloon like" cells forming several layers, particularly in the places of the rumen mucosa more protected from an abrasive action of solid feed. This was more evident in C animals. The squamous cells covering the papillary tip showed cytoplasmic protrusion, representing remains of the attachment sites of desmosomes, which increased the total absorptive surface and were more numerous and higher in T compared to C animals. It might be hypothesized that SMCFA supplementation in MR could better regulate epithelial cell proliferation and probably have an "emollient effect" leading to an easier "peeling" that might increase efficiency for nutrient transport across the epithelium.

Osteogenic response and osteoprotective effects in vivo of a nanostructured titanium surface with antibacterial properties.

In implantology, as an alternative approach to the use of antibiotics, direct surface modifications of the implant addressed to inhibit bacterial adhesion and to limit bacterial proliferation are a promising tactic. The present study evaluates in an in vivo normal model the osteogenic response and the osteointegration of an anodic spark deposition nanostructured titanium surface doped with gallium (ASD + Ga) in comparison with two other surface treatments of titanium: an anodic spark deposition treatment without gallium (ASD) and an acid etching treatment (CTR). Moreover the study assesses the osteoprotective potential and the antibacterial effect of the previously mentioned surface treatments in an experimentally-induced peri-implantitis model. The obtained data points out a more rapid primary fixation in ASD and ASD + Ga implants, compared with CTR surface. Regarding the antibacterial properties, the ASD + Ga surface shows osteoprotective action on bone peri-implant tissue in vivo as well as an antibacterial effect within the first considered time point.

Cytocompatibility and cellular internalization mechanisms of SiC/SiO2 nanowires.

First evidence of in vitro cytocompatibility of SiC/SiO2 core-shell nanowires is reported. Different internalization mechanisms by adenocarcinomic alveolar basal epithelial cells, monocytic cell line derived from an acute monocytic leukemia, breast cancer cells, and normal human dermal fibroblasts are shown. The internalization occurs mainly for macropinocytosis and sporadically by direct penetration in all cell models considered, whereas it occurred for phagocytosis only in monocytic leukemia cells. The cytocompatibility of the nanowires is proved by the analysis of cell proliferation, cell cycle progression, and oxidative stress on the cells treated with NWs as compared to controls. Reactive oxygen species generation was detected as an early event that then quickly run out with a rapid decrease only in adenocarcinomic alveolar basal epithelial and human dermal fibroblasts cells. In all the cell lines, the intracellular presence of NWs induce the same molecular events but to a different extent: peroxidation of membrane lipids and oxidation of proteins. The NWs do not elicit either midterm (72 h) or long-term (10 days) cytotoxic activity leading to irreversible cellular damages or death. Our results are important in view of a possible use of SiC/SiO2 core-shell structures acting as biomolecule-delivery vectors or intracellular electrodes.

Periostin improves cell adhesion to implantable biomaterials and osteoblastic differentiation on implant titanium surfaces in a topography-dependent fashion.

Periostin is a matricellular protein highly expressed in periodontal ligament and periostium and has been shown to be required for tissue development and maintenance. We showed that the adhesion of murine osteoblastic MC3T3 cells to thiolated hyaluronic acid/polyethyleneglycol hydrogels was greatly improved by enrichment with periostin. Polished or sand-blasted/acid-etched (SLA) commercially pure titanium surfaces were also coated with this protein and periostin ameliorated cell adhesion and dramatically affected cell morphology on both surfaces, as assessed at fluorescence microscopy, scanning electron microscopy, and chemiluminescence-based viability assay. Moreover, periostin increased the expression of alkaline phosphatase, osteoprotegerin, connective tissue growth factor, collagen 1a1, osteocalcin, Runx2, and osterix transcription factors on smooth surfaces. However, it did not affect, or even decreased, the expression of these genes on SLA discs. Transcript levels for connexin 43 were greatly increased on both surfaces in the presence of periostin. Taken together, these results show that periostin coatings can be a viable approach to improve cell adhesion and differentiation on implantable biomaterials.

Preliminary study on the mineral apposition rate in distal femoral epiphysis of New Zealand white rabbit at skeletal maturity.

Studies investigating the effect of different factors on the skeletal system require characterization of an appropriate animal model. Rabbits are among the most commonly studied animals for medical research, being used in about 35% of musculoskeletal research studies. The present dynamic cross-sectional histomorphometric study quantitatively determined mineral apposition rates (MARs) in the distal femoral epiphysis in four regions of interest (ROIs) in New Zealand white rabbits. ROIs included the craniolateral (CrL), caudolateral (CaL), craniomedial (CrM) and caudomedial (CaM) areas, using a reference height at different stages of skeletal maturity corresponding to experimental ages of 6, 7 and 8 months old (M6, M7 and M8). We evaluated whether a correlation exists in MARs between the times and the regions examined. Such data could be used in studies on growth of the rabbit's femur, on biomaterials for bone integration or regeneration and on growth disturbances produced by various pathologic factors. We found no interaction at the experimental times; thus, M6, M7 and M8 are considered homogeneous in terms of MARs. The velocity profiles of the MARs were statistically significantly different among the considered ROIs. For all experimental times, the CrM region had a higher MAR than the other ROIs. Both the CrM and CaM ROIs had higher MARs than the corresponding lateral ROIs. Our results indicate that bone formation is not constant within the cross-section, but is statistically different between the ROIs considered.

In vitro cellular response and in vivo primary osteointegration of electrochemically modified titanium.

Anodic spark deposition (ASD) is an attractive technique for improving the implant-bone interface that can be applied to titanium and titanium alloys. This technique produces a surface with microporous morphology and an oxide layer enriched with calcium and phosphorus. The aim of the present study was to investigate the biological response in vitro using primary human osteoblasts as a cellular model and the osteogenic primary response in vivo within a short experimental time frame (2 and 4 weeks) in an animal model (rabbit). Responses were assessed by comparing the new electrochemical biomimetic treatments to an acid-etching treatment as control. The in vitro biological response was characterized by cell morphology, adhesion, proliferation activity and cell metabolic activity. A complete assessment of osteogenic activity in vivo was achieved by estimating static and dynamic histomorphometric parameters at several time points within the considered time frame. The in vitro study showed enhanced osteoblast adhesion and higher metabolic activity for the ASD-treated surfaces during the first days after seeding compared to the control titanium. For the ASD surfaces, the histomorphometry indicated a higher mineral apposition rate within 2 weeks and a more extended bone activation within the first week after surgery, leading to more extensive bone-implant contact after 2 weeks. In conclusion, the ASD surface treatments enhanced the biological response in vitro, promoting an early osteoblast adhesion, and the osteointegrative properties in vivo, accelerating the primary osteogenic response.

In vivo assessment of the osteointegrative potential of phosphatidylserine-based coatings.

The successful implantation of titanium-based implants for orthopaedic and dental applications is often hindered because of their mobility, which arises because of a lack of direct binding of the metal surface to the mineral phase of the surrounding bone. Ceramic coatings, although ensuring the integration of the implant within the tissue, are unstable and carry risks of delamination and of failure. Recently, a novel biomimetic approach has been developed where porous titanium implants are coated with calcium-binding phospholipids able to catalyse the nucleation of discrete apatite crystals after only 30 min incubation in simulated body fluids. The present work assesses the osteointegrative potential of this new class of coatings in an in vivo rabbit model and compares its performance with those of bare porous titanium and hydroxyapatite-coated titanium. The data obtained show that phosphatidylserine-based coatings, whilst resorbing, drive the growing bone into apposition with the metal surface. This is in contrast to the case of bare titanium.

Bone response to polymers based on poly-lactic acid and having different degradation times.

Authors studied two degradable and resorbable polymers derived from lactic acid: poly-L-Lactic acid (PLLA), with a relatively long time of degradation (longer than 6 months, PL10 Purac NL); poly-DL-Lactic acid (PDLLA), with a relatively short time of degradation (shorter than 6 months, PDL Purac NL). The animal species was the young adult New Zealand White rabbit. The in-vivo study was performed by implantation of small cylinders of 10 x 3 mm in size (length x diameter) in the distal metaepiphysis of the femur; 34 cylinders have been implanted. Retrievals of PLLA specimens took place at 3, 6, 9, 12 and 24 months; for PDLLA specimens at 1, 2, 4 months. Polarized light microscopy of undecalcified tissue sections was performed. The analysis for PLLA and PDLLA has shown a favorable response of bone tissue: alterations in the bone repair, growth and remodeling have not been observed. PLLA is persistent at the times studied; there is never a tight apposition between bone and PLLA implant and an intervening fibrous layer has often been observed. PDLLA is not persistent at the times studied and it degrades quite fast; bone repair of the empty implantation's hole occurs by bony growth from the endosteal trabeculae. The newly formed bone covers the hole's walls with an elongation parallel to them. For both polymers, whether the degradation is fast or slow, the material's substitution by newly formed bone never starts from the walls of the implantation hole. Only after the complete disappearance of the polymeric material newly formed bone begins to fill the hole.

Energy dispersive analysis (EDX) of a degradable bioactive-glass coating on Ti6Al4V in-vivo.

The bioactive-glass coating of metallic substrates provides a gradually degrading interface which can be used to favor the bony integration of the implant by the physiologic processes of bone turn-over and remodeling. Twelve New Zealand White rabbits, about 2700 g of weight, were operated by the sagittal insertion of a bioactive-glass coated plate of Ti6Al4V. Retrievals were performed at 4, 8 and 12 weeks. Undecalcified specimens were embedded in methyl-metacrylate and sectioned at 100 microns of thickness. Blocks were grinded and had an electroconductive coating to be examined by scanning electron microscopy (SEM), back scattering electron microscopy (BSEM) and X-ray energy dispersive spectroscopy microanalysis (EDX). EDX allows to evaluate quantitatively the gradual process of coating degradation. Areas of 200 microns in square were analyzed at the interface between bone and coating to determine their elemental composition. Silicon was the key marker for the presence of the glass. Morphological analysis confirms that a tight apposition with bone can be obtained by utilizing the bioactive glass coating of metal. Results of energy dispersive analysis support the mechanism of a gradual degradation of the bioactive glass coating and its integration with bone, since the presence of silicon can be documented within the newly formed bone after the coating has disappeared.

On the presence of ganglion cells in the intracranial portion of the accessory nerve (XI cranial nerve) in some mammals.

The intracranial tract of the accessory nerve (XI cranial nerve) was studied in some mammals (equines, domestic and wild ruminants, pig, carnivores, rabbit, nutria, guinea pig, hamster, hedgehog). The specimens were embedded in paraffin or paraplast, the sections were stained with cresyl violet, haematoxylin and eosin, or submitted to argentic impregnation. Pseudounipolar ganglion cells were found in all the mammals examined, with the exception of the cat. The number of cells and their variability in the different species and subjects were related. The topography and morphology of the cells were described. This comparative study has demonstrated that the accessory nerve is not a entirely motor nerve, but it is a mixed, motor and sensitive, nerve. Nevertheless, we think further studies are necessary in order to establish the peripheral distribution, the central pathway and the functional role of the pseudounipolar neurons found in the intracranial tract of the accessory nerve.

X-ray diffraction and polarizing optical microscopy investigation of the structural organization of rabbit tibia.

X-ray diffraction and polarized optical microscopy investigations were carried out on thin sections of rabbit tibia in order to study the morphological organization of the structural components of this tissue, which often is utilized to test bone response to implants. In the optical microscope, the lateral face as well as the lateral portion of the caudal face exhibit a lamellar structure with an alternation of dark and bright lamellae running parallel to the long axis of the tibia. In contrast, both in the medial face and in the medial portion of the caudal face there are numerous osteonic structures. In spite of the complexity of this morphological organization, the results of small- and high-angle X-ray diffraction analyses indicate that the structural relationship between collagen fibrils and inorganic crystals is quite similar to that observed in single osteons and allows evaluation of the orientation of the two main structural components. Both collagen fibrils and apatitic crystallites are preferentially oriented parallel to the long axis of the tibia. The degree of orientation is greater in the thickness than in the plane of the lamellae, suggesting that collagen fibrils and inorganic crystallites lie preferentially in the plane of the lamellae, where they follow an oblique course. The degree of orientation of the apatitic crystallites is higher in the lateral face than in the medial and caudal faces, in agreement with the optical microscopic images. The results provide information that must be taken into account when evaluating the structural modifications of bone due to the insertion of a prosthetic device.

Bioactive glass coating: physicochemical aspects and biological findings.

Glass coating material was investigated before and after spraying to see whether it maintained the chemical and physical properties; in vivo and in vitro studies were done to evaluate the biological results. Following the spraying process, the Biovetro coating on the TiAl6V4 plate--as evidenced from chemical and physical analysis--maintains the properties of the original glass unchanged as far as the amorphous structure and its behaviour in a hydrolytic environment are concerned. In vitro and in vivo studies underline the positive features of the coating obtained by the plasma spray process, confirming that it has the typical properties of bioactive glass patented under the trade mark, Biovetro, i.e. biodegradability and osteoconductivity already confirmed by previous experimental protocols carried out by our group using powdered and fibre Biovetro.