The biocompatibility of austenitic stainless steels can be improved by means of surface engineering techniques. In the present research it was investigated if low temperature nitrided AISI 316L ...austenitic stainless steel may be a suitable substrate for bioactive protein coating consisting of collagen-I. The biocompatibility of surface modified alloy was studied using as experimental model endothelial cells (human umbilical vein endothelial cells) in culture. Low temperature nitriding produces modified surface layers consisting mainly of S phase, the supersaturated interstitial solid solution of nitrogen in the austenite lattice, which allows to enhance surface microhardness and corrosion resistance in PBS solution. The nitriding treatment seems to promote the coating with collagen-I, without chemical coupling agents, in respect of the untreated alloy. For biocompatibility studies, proliferation, lactate dehydrogenase levels and secretion of two metalloproteinases (MMP-2 and MMP-9) were determined. Experimental results suggest that the collagen protection may be favourable for endothelial cell proliferation and for the control of MMP-2 release.
Although sphingosine 1-phosphate (S1P) has been considered a potent regulator of skeletal muscle biology, acting as a physiological anti-mitogenic and prodifferentiating agent, its downstream ...effectors are poorly known. In the present study, we provide experimental evidence for a novel mechanism by which S1P regulates skeletal muscle differentiation through the regulation of gap junctional protein connexin (Cx) 43. Indeed, the treatment with S1P greatly enhanced Cx43 expression and gap junctional intercellular communication during the early phases of myoblast differentiation, whereas the down-regulation of Cx43 by transfection with short interfering RNA blocked myogenesis elicited by S1P. Moreover, calcium and p38 MAPK-dependent pathways were required for S1P-induced increase in Cx43 expression. Interestingly, enforced expression of mutated Cx43(Delta130-136) reduced gap junction communication and totally inhibited S1P-induced expression of the myogenic markers, myogenin, myosin heavy chain, caveolin-3, and myotube formation. Notably, in S1P-stimulated myoblasts, endogenous or wild-type Cx43 protein, but not the mutated form, coimmunoprecipitated and colocalized with F-actin and cortactin in a p38 MAPK-dependent manner. These data, together with the known role of actin remodeling in cell differentiation, strongly support the important contribution of gap junctional communication, Cx43 expression and Cx43/cytoskeleton interaction in skeletal myogenesis elicited by S1P.
Among the titanium alloys employed as implant materials, the Ti–6Al–4V alloy is still widely used. Ti–6Al–4V titanium alloy samples, in untreated state and subjected to treatments in air by furnace ...or glow-discharge processes, were put in contact with human umbilical vein endothelial cells (HUVEC) in order to evaluate their effects on biocompatibility. In HUVEC kept for 48
h in the presence of the three sample types neither cell proliferation nor protein content nor lactate dehydrogenase release in the culture medium are affected, while apoptosis is induced after 48- and 96-h contact of the cells with the untreated sample type, and after 96-h contact with the plasma treated one, the furnace treated sample type being ineffective. The expression of two adhesion molecules, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) was also studied. The incubation of HUVEC with the three sample types for 48 or 96
h induces a significant increase in ICAM-1 protein levels, in comparison with control cells, while VCAM-1 expression is not detectable. In the same way, TNF-α release in the culture medium, assayed after 48- and 96-h contact of the cells with the three sample types, is significantly higher, in comparison with control, even if the highest values are registered in the presence of the untreated samples. Taken together, these data indicate that, although Ti–6Al–4V alloy samples, and in particular the treated ones, show a good biocompatibility, attention must be given to the first signs of inflammation.
This study tested the hypothesis that 1,25-dihydroxyvitamin D
3 1,25(OH)
2D
3 plays a role in human umbilical vein endothelial cells (HUVEC) cultures. HUVEC were incubated with 10 or 100
nM 1,25(OH)
...2D
3 for 24
h, in the absence or presence of 40
ng/ml tumor necrosis factor-α (TNF-α) or 2
ng/ml interleukin-1α (IL-1α). 1,25(OH)
2D
3 did not affect HUVEC viability and proliferation, while TNF-α, alone or in combination with the hormone, significantly inhibited HUVEC viability.
3Hthymidine incorporation in HUVEC treated with TNF-α or IL-1α significantly decreased, in the absence or in the presence of the hormone, while the levels of vitamin D receptor markedly increased in the presence of 1,25(OH)
2D
3 alone or associated with TNF-α or IL-1α, in comparison to the control. The noteworthy increase in protein levels of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) induced by TNF-α was significantly decreased after incubation of the cells with 1,25(OH)
2D
3, this effect not being seen on E-selectin expression. Neither apoptosis nor nuclear translocation of NF-κB, induced in HUVEC by TNF-α was influenced by 1,25(OH)
2D
3 treatment.
The aim of this study was to investigate whether the vitamin D analogue KH 1060 could exert a suppressive action on Tumor necrosis factor-alpha (TNF-α). The chimeric anti-TNF-α monoclonal antibody ...(anti-TNF), alone or in combination with KH 1060, was also used. KH 1060 (0.01, 0.1, 1 nM) significantly inhibited cell proliferation, determined after 5 days by
3Hthymidine incorporation, when peripheral blood mononuclear cells (PBMC), obtained from healthy subjects, were stimulated with phytohaemagglutinin (PHA) and incubated for 24 h in the absence and in the presence of lipopolysaccharide (LPS). In the same experimental conditions, anti-TNF exerted a significant inhibition on PBMC proliferation, at the lowest doses (0.001, 0.01 μg/ml) in the absence of LPS, and at 0.001, 1, 10 μg/ml in its presence. A synergistic inhibition was registered combining KH 1060 and anti-TNF, at well-defined concentrations. 0.1 nM KH 1060 produced a significant decrease in TNF-α levels, determined by ELISA, although less remarkable than in the presence of anti-TNF. This decrease was synergistic, associating 0.1 nM KH 1060 and 0.1 μg/ml anti-TNF. VDR protein levels were increased by 0.1 nM KH 1060, 0.1 μg/ml anti-TNF or their combination. The protein levels of two oncogenes, Bax and Bcl-2, remained unchanged, when PBMC were incubated with KH 1060, anti-TNF or their combination in the absence of LPS, while, in its presence, an increase was registered. The demonstrated anti-TNF-α effect of KH 1060 may suggest for this compound an immunosuppressive action and the possibility to synergistically act with other drugs.
Infliximab treatment demonstrated clinical and endoscopic benefits in active refractory and fistulizing Crohn's disease. The aim of this research was to investigate the proliferative response of ...peripheral blood mononuclear cells (PBMC) obtained from patients with active and fistulizing Crohn's disease treated with infliximab therapy. PBMC proliferation and VDR protein levels were also studied when 1,25(OH)2D3 or its analogues (EB 1089, KH 1060) were added to cells cultures. At day 5 of culture, the proliferation of PBMC obtained from patients responsive to the therapy showed a remarkable decrease (about 60%) at T6 (after two infusions) with respect to T0 (before the first infusion). On the contrary, in the unresponsive patient, the proliferative response was four times higher at T6 in comparison with T0. Vitamin D derivatives induced a decrease in cell proliferation higher in responsive patients than in the unresponsive one. Increased VDR levels during therapy were registered only in the unresponsive patient. Our results indicate that PBMC proliferation and VDR expression may be useful indicators to predict the response of patients with Crohn's disease to the infliximab therapy.
PDF
