Comparison between different cell sources and culture strategies for tendon tissue engineering.

The aim of this study was to evaluate the effect of an in vitro mechanical stimulation by the use of a bioreactor on an engineered tendon for 7 and 14 days and to analyze the effect of the use of different cell sources: tenocytes, dermal fibroblasts or Adipose-Derived Stem Cells (ASCs), isolated from pig tissues. Histology showed a re-organization of the neo-tissue derived from the three cell populations along the direction of the stimulus. At T7, cells morphology was preserved while an increased cellular suffering at T14 was observed for all cell populations. Tenocytes exhibited higher survival than other cells. A stable immunopositivity for collagen type 1 or 3 at both time points was also observed. In conclusion, dermal fibroblasts and ASCs represent an interesting alternative and in vitro culture with mechanical stimuli may enhance the maturation of a tendon-like tissue.

The analysis of different scaffolds and the benefit of fibrin glue for tendon tissue engineering at different culture times.

This study evaluated a tendon substitute model. Tenocytes were isolated from pig Achilles tendon, seeded onto scaffolds (Opocrin 2%, Typeone 3% and Symatese 2%) and studied by histology, immunofluorescence for collagen type 1 and 3 and biochemical analysis to assess cellularity. The permeability of these compounds was evaluated in the presence or absence of fibrin glue. Opocrin 2% was the best choice for cellular distribution within the scaffolds, which were then cultured for T0, T4, T7 and T10 days. Fibrin glue has been strongly supportive for the survival of cells with a significant increase in DNA content at T10 (P<0.05). Moreover, the synthetic activity of fibrin-free scaffolds was always negative. Lastly, a progressive increase in collagen 1 and 3 with fibrin-glue was observed. However, static culture is not sufficient to support long-term cellular activities and at T10 there is still a lack of organized matrix similar to the native tissue.

The effects of dietary verbascoside on blood and liver oxidative stress status induced by a high n-6 polyunsaturated fatty acids diet in piglets.

Twenty-four weaned female Hypor piglets (10.9 ± 0.1 kg mean BW) were used to evaluate the antioxidant effect of a natural extract, titrated in verbascoside, on blood and liver oxidative status in relation to a high intake of n-6 PUFA, inducing oxidative stress. Piglets were assigned to 1 of 3 experimental groups; the first group was fed a diet with 9% sunflower oil (T1) and the second received the sunflower oil diet supplemented with 5 mg of verbascoside/kg feed from Verbenaceae extract (Lippia spp.; T2). The third group was fed a control diet (CTR), in which an isoenergetic replacement of oil by starch was done. Blood samples were collected at the beginning and the end of the trial (30 d). At the end of the trial, the animals were slaughtered and the liver specimens were collected. Oxidative stress markers, including total antiradical activity, superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activities, were determined in blood samples. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and γ-glutamyl transferase (GGT) plasma levels were also evaluated. Immunohistochemistry and western blot analyses were performed in liver to evaluate heat shock protein (Hsp) 70, Hsp90, and Kupffer and Ito cell activation. Liver activities of SOD, GPX, and CAT were also determined. Total antiradical activity in blood and red blood cells were affected (P < 0.01) by dietary treatments. The n-6 PUFA supplementation at a high dosage for 30 d induced oxidative stress, decreasing total antiradical activity in blood and red blood cells (CTR vs. T1 + T2; P < 0.01) and plasma CAT activity (CTR vs. T1 + T2; P = 0.088) and increasing ALT value (CTR vs. T1 + T2; P < 0.01). Also, in liver, the CAT and GPX activities tended to be lower in pigs fed n-6 PUFA diets than pigs fed a control diet (CTR vs. T1 + T2; = 0.090 and = 0.085, respectively). The liver samples presented a normal architecture and no Ito and Kupffer cell activations were observed. In liver, the SOD activity tended to be lower in the T1 group (P = 0.064) than in the CTR and T2 groups. Moreover, the level of Hsp70 was higher (P < 0.01) in the T1 group than the CTR and T2 groups. These data suggest that the dose of dietary verbascoside partially restores the antioxidant status of the liver without affecting the systemic responses to oxidative stress induced by a high-fat diet.

Effect of silver nanocoatings on catheters for haemodialysis in terms of cell viability, proliferation, morphology and antibacterial activity.

The onset of infections associated to bacterial proliferation and biofilm formation on indwelling medical devices represents the major risk of morbidity and mortality among patients. In order to contain the risk of infections in clinical practice, there is a growing interest nowadays in silver-based products due to the strong antimicrobial efficacy of silver against a broad spectrum of microorganisms. In this work, temporary catheters for haemodialysis were coated with silver nano-particles through the in situ photo-reduction of a silver salt in alcoholic solution. A homogeneous distribution of silver particles firmly bonded to the substrate was obtained through the adopted technique. An optimisation study was required to define the amount of silver, in order to obtain good efficacy against Gram-positive and Gram-negative bacteria and no cytotoxic effect. At this purpose, three concentrations of silver, 0.1, 0.25 and 0.5 wt%, have been deposited and tested with respect to bacterial reduction percentage and cellular response. Particularly, bacterial enumeration on Escherichia coli and Staphylococcus aureus, and BrdU incorporation, TUNEL assay and Actin staining on a selected primary cell population were performed on catheters treated with the different silver solutions. The silver percentages tested demonstrated strong antibacterial properties together with a good cellular response, thus indicating that the developed product could be proposed in clinical practice and that the lower percentage tested can be preferred with evident advantages in terms of costs.

Current surgical options for articular cartilage repair.

The articular cartilage lesions represent one of the major unsolved problems in the orthopaedic surgery. This is because articular cartilage has a limited capacity of self-repair following trauma. The aim of this study is to review the different surgical options for articular cartilage repair. They can be divided into three groups: techniques without transplant of cells or tissues; techniques based on the transplantation of tissues; the tissue engineering techniques.The first group includes the joint debridement and the techniques based on the bone marrow-stimulation principle.The second group includes the transplantation of periosteum and the transplantation of autologous or allogeneic osteochondral plugs. The tissue engineering techniques could be further divided as follows: methods based on the transplantation of cells either in solution, or in the form of microspheres, or carried on a biocompatible scaffold; the transplant of cartilage fragments; the cell-free techniques, based on the use of an acellular scaffold, able to entrap the reparative cells recruited from the host tissue and to guide their differentiation toward a chondral phenotype.In this work we present various options for the treatment of chondral or osteochondral lesions. Today, however, due to the lack of comparative studies, it is not always possible to define the best treatment choice for the different cartilage pathologies.