Cell adhesion on nanotextured slippery superhydrophobic substrates.

In this work, the response of Saos2 cells to polymeric surfaces with different roughness/density of nanometric dots produced by a tailored plasma-etching process has been studied. Topographical features have been evaluated by atomic force microscopy, while wetting behavior, in terms of water-surface adhesion energy, has been evaluated by measurements of drop sliding angle. Saos2 cytocompatibility has been investigated by scanning electron microscopy, fluorescent microscopy, and optical microscopy. The similarity in outer chemical composition has allowed isolation of the impact of the topographical features on cellular behavior. The results indicate that Saos2 cells respond differently to surfaces with different nanoscale topographical features, clearly showing a certain inhibition in cell adhesion when the nanoscale is particularly small. This effect appears to be attenuated in surfaces with relatively bigger nanofeatures, though these express a more pronounced slippery/dry wetting character.

Osteoblast-like cell behavior on plasma deposited micro/nanopatterned coatings.

The behavior of cells in terms of cell-substrate and cell-cell interaction is dramatically affected by topographical characteristics as shape, height, and distance, encountered in their physiological environment. The combination of chemistry and topography of a biomaterial surface influences in turns, important biological responses as inflammatory events at tissue-implant interface, angiogenesis, and differentiation of cells. By disentangling the effect of material chemistry from the topographical one, the possibility of controlling the cell behavior can be provided. In this paper, surfaces with different roughness and morphology were produced by radiofrequency (RF, 13.56 MHz) glow discharges, fed with hexafluoropropylene oxide (C(3)F(6)O), in a single process. Coatings with different micro/nanopatterns and the same uppermost chemical composition were produced by combining two plasma deposition processes, with C(3)F(6)O and tetrafluoroethylene (C(2)F(4)), respectively. The behavior of osteoblast-like cells toward these substrates clearly shows a strict dependence of cell adhesion and proliferation on surface roughness and morphology.

Increasing cell adhesion on plasma deposited fluorocarbon coatings by changing the surface topography.

In designing new biomaterials, it is of outstanding importance to consider how cells respond to specific chemical and topographical features on the material surface. The behavior of most cell types in vivo is strictly related to specific chemical and topographical cues that characterize the extra cellular environment. In particular, during their lives cells react to topographical patterns such as those of the extracellular matrix (ECM), of micro and/or nanometric dimensions. The production of micrometric and/or nanometric features on artificial materials usually involves expensive and time-consuming methods of manufacturing, such as electron beam and colloidal lithography. In this article, different "Teflon-like" structured surfaces were deposited from tetrafluoroethylene (C(2)F(4))-fed plasmas, for the study of cell adhesion and growth. The reaction of different cell lines to different topographical features was evaluated and compared with cell behavior on flat samples with the same chemical composition. Cell adhesion was calculated from area covered by cells at different time of culture. Beside this, cell proliferation was determined with the MTT test. Cell morphology and filopodia interaction with the nanofeatures were also estimated by optical and scanning electron microscopy. A dramatic difference both in adhesion and growth was found between cells seeded on flat and rough surfaces with the density and spreading of adhered cells varying as a function of the roughness of coatings.

Phototoxicity and cytotoxicity of chlorophyll a/cyclodextrins complexes on Jurkat cells.

The aggregation status of chlorophyll a (Chl a) and the ability of four cyclodextrins, hydroxypropyl-beta-cyclodextrin (HP-beta-CD), hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD), heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DIMEB), and heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TRIMEB), to solubilize the pigment in the complete cellular medium RPMI 1640 was estimated by means of UV-Vis absorption and static resonance light scattering (RLS) measurements. The results indicate that the pigment interacts with cyclodextrins in the cellular medium differently to that observed in water. The cytotoxic and phototoxic activity of these complexes towards human leukemia T-lymphocytes (Jurkat cells) was tested by means of experiments aimed to discriminate between the intrinsic toxicity and the toxicity induced by light. The overall data indicate that the HP-beta-CD is the cyclodextrins having the best characteristics to form with Chl a a potential supramolecular system for the photodynamic therapy.

Lipoprotein(a) in the cerebrospinal fluid of neurological patients with blood-cerebrospinal fluid barrier dysfunction.

BACKGROUND: Lipoprotein(a) [Lp(a)] is a recognized pathogenic particle in human plasma, but its presence in the cerebrospinal fluid and its possible role in the central nervous system have not been documented. We tested the hypothesis that apolipoprotein(a) [apo(a)], free or as a component of the Lp(a) particle, can cross the blood-cerebrospinal fluid barrier and be found in the cerebrospinal fluid of patients affected by neurologic pathologies. METHODS: We studied paired cerebrospinal fluid/serum samples from 77 patients with inflammatory (n=20) or noninflammatory (n=34) blood-cerebrospinal fluid barrier dysfunction and without blood-cerebrospinal fluid barrier dysfunction (n=23). We used ELISA to measure Lp(a) concentrations and Western blot and immunodetection to analyze apo(a) isoforms in native and reducing conditions. RESULTS: Entire Lp(a) with either small or large apo(a) isoforms was present in the cerebrospinal fluid of patients with blood-cerebrospinal fluid barrier dysfunction, regardless of its pathogenesis. Multiple linear regression analysis showed that both serum Lp(a) concentration (P=0.003) and cerebrospinal fluid/serum albumin ratio (P<0.001) were predictors of the Lp(a) concentration in cerebrospinal fluid. CONCLUSIONS: Our results demonstrate that Lp(a) can cross a dysfunctional blood-cerebrospinal fluid barrier. The unusual presence of Lp(a) in the cerebrospinal fluid could extend some of its known pathogenic effects to the central nervous system.

Mechanism for the homocysteine-enhanced antifibrinolytic potential of lipoprotein(a) in human plasma.

Lipoprotein(a) and total plasma homocysteine levels are now established as independent atherothrombogenic risk factors. A distinctive pathophysiological feature of lipoprotein(a) is its antifibrinolytic activity, an effect dependent on plasma concentration and high affinity for fibrin of its small size apo(a) component. A stimulating effect of homocysteine on purified lipoprotein(a) has been proposed. However, little is known about their specific interactions in human plasma. We demonstrate by immunochemical, ligand-binding and plasminogen activation studies, that homocysteine modifies the structure and function of lipoprotein(a) in human plasma; it reduces the apo(a)/apoB disulfide bond causing the appearance of free apo(a) with high affinity for fibrin that inhibits plasminogen binding and plasmin formation (r= -0.995, p =0.002). These effects were evident particularly in plasma samples containing lipoprotein(a) with low affinity for fibrin and more than 22 kringles apo(a) isoforms. In contrast, for plasmas containing high fibrin affinity lipoprotein(a) (less than 22 kringles apo[a] isoforms) no significant change neither in fibrin binding nor in plasmin formation was observed. Furthermore, isolated apo(a) recombinants (10 to 34 kringles) that have been shown to display size-independent high affinity for fibrin were not affected by homocysteine, thus confirming lipoprotein(a) as its main target. These results suggest that the pro-atherogenic role already conferred to lipoprotein(a) by small apo(a) isoforms may be extended to large apo(a) isoforms if released in plasma by homocysteine, as this mechanism reveals their high fibrin affinity. Lipoprotein(a) and homocysteine may therefore constitute, if acting in concert, a new risk factor for athero-thrombotic vascular disease.

APO(a) variants and lipoprotein(a) in men with or without myocardial infarction.

The lipoprotein Lp(a) with high plasma concentration is an independent genetic determinant for cardiovascular diseases. It was investigated as a quantitative factor of risk for myocardial infarction. A total of 345 Italian subjects, 127 Cases and 218 Controls, were studied. Lipids and lipoproteins were compared. Cases had atherogenic traits, such as lower HDL cholesterol and higher triglycerides than Controls. In particular, they had Lp(a) concentrations over the risk threshold, (median, 27 mg/dl in Cases vs 17 mg/dl in Controls; P = 0.0075, Mann-Whitney test) which confirmed the association of this parameter with the disease. Two main functional variants of the apo(a) gene, KringleIV and penta-nucleotide repeat, (PNR) were analyzed. Allele and genotype frequency distributions differed between Cases and Controls. Lp(a) concentrations differed according to PNR genotypes in Controls: subjects having alleles >8 showed lower Lp(a). This was not found in Cases. They had a higher prevalence of the smaller KringleIV alleles, the high Lp(a)-expressing ones. In Cases, genotypes consisting of two small KringleIV alleles were prevalently associated to PNR 8/9 and 8/10, thus preventing Lp(a) lowering. The putative apo(a) enhancer within LINE1 in the apo(a)-plasminogen intergenic region was investigated for functional polymorphisms. No variants that could be associated to the Lp(a) variability were found.