Morphofunctional reaction of leukocytes and platelets in in vitro contact with a-C:H:SiOx -coated Ti-6Al-4V substrate.

The article deals with the plasma-assisted chemical vapor deposition of 0.3-1.4 µm thick a-C:H:SiOx films in a mixture of argon and polyphenylmethylsiloxane vapor onto the Ti-6Al-4V alloy substrate, which is often used as an implant material. The a-C:H:SiOx film structure is studied by the Fourier-transform infrared and Raman spectroscopies. The pull-off adhesion test assesses the adhesive strength of a-C:H:SiOx films, and the ball-on-disk method is employed to measure their wear rate and friction coefficient. According to these studies, a-C:H:SiOx films are highly adhesive to the Ti-6Al-4V substrate, have low (0.056) friction coefficient and wear rate (9.8 × 10-8  mm3  N-1  m-1 ) in phosphate-buffered saline at 40°C. In vitro studies show neither thrombogenicity nor cytotoxicity of the a-C:H:SiOx film for the human blood mononuclear cells (hBMNCs). The in vitro contact between the hBMNC culture and a-C:H:SiOx films 0.8-1.4 µm thick deposited onto Ti-6Al-4V substrates reduces a 24-hour secretion of pro-inflammatory cytokines and chemokines IL-8, IL-17, TNFα, RANTES, and MCP-1. This reduction is more significant when the film thickness is 1.4 µm and implies its potential anti-inflammatory effect and possible application in cardiovascular surgery. The dependence is suggested for the concentration of anti-inflammatory cytokines and chemokines and the a-C:H:SiOx film thickness, which correlates with the surface wettability and electrostatic potential. The article discusses the possible applications of the anti-inflammatory effect and low thrombogenicity of a-C:H:SiOx films in cardiovascular surgery.

Amorphous-Crystalline Calcium Phosphate Coating Promotes In Vitro Growth of Tumor-Derived Jurkat T Cells Activated by Anti-CD2/CD3/CD28 Antibodies.

A modern trend in traumatology, orthopedics, and implantology is the development of materials and coatings with an amorphous-crystalline structure that exhibits excellent biocopatibility. The structure and physico-chemical and biological properties of calcium phosphate (CaP) coatings deposited on Ti plates using the micro-arc oxidation (MAO) method under different voltages (200, 250, and 300 V) were studied. Amorphous, nanocrystalline, and microcrystalline statesof CaHPO4 and ß-Ca2P2O7 were observed in the coatings using TEM and XRD. The increase in MAO voltage resulted in augmentation of the surface roughness Ra from 2.5 to 6.5 µm, mass from 10 to 25 mg, thickness from 50 to 105 µm, and Ca/P ratio from 0.3 to 0.6. The electrical potential (EP) of the CaP coatings changed from -456 to -535 mV, while the zeta potential (ZP) decreased from -53 to -40 mV following an increase in the values of the MAO voltage. Numerous correlations of physical and chemical indices of CaP coatings were estimated. A decrease in the ZP magnitudes of CaP coatings deposited at 200-250 V was strongly associated with elevated hTERT expression in tumor-derived Jurkat T cells preliminarily activated with anti-CD2/CD3/CD28 antibodies and then contacted in vitro with CaP-coated samples for 14 days. In turn, in vitro survival of CD4+ subsets was enhanced, with proinflammatory cytokine secretion of activated Jurkat T cells. Thus, the applied MAO voltage allowed the regulation of the physicochemical properties of amorphous-crystalline CaP-coatings on Ti substrates to a certain extent. This method may be used as a technological mechanism to trigger the behavior of cells through contact with micro-arc CaP coatings. The possible role of negative ZP and Ca2+ as effectors of the biological effects of amorphous-crystalline CaP coatings is discussed. Micro-arc CaP coatings should be carefully tested to determine their suitability for use in patients with chronic lymphoid malignancies.

Direct effects of interleukin-7 on the function of human T cells in vitro.

СD3+ T lymphocytes were isolated by positive magnetic separation from the peripheral blood of healthy donors. In the absence of any additional activating stimuli, interleukin-7 (IL-7) was shown to augment the levels of T cells expressing CD25 activation marker both in СD4-positive and in CD4-negative effector memory (CD45RA-CD197-) T cell subsets, as well as in terminally differentiated (CD45RA+CD197-) Т cells, without significantly affecting the activation status of naive (CD45RA+CD197+) and central memory (CD45RA-CD197+) T cells. In addition, IL-7 noticeably enhanced the production of IL-2, interferon-γ (IFN-γ), and IL-10, but not IL-4, in T cells. The direct effects of IL-7 on T cell activation induced in vitro by MACSiBead™ particles coated with CD2, CD3, and CD28 antibodies (Abs) were also investigated. Upon cell activation, IL-7 significantly augmented the levels of CD25+ T cells in naive (CD45RA+CD197+), central memory (CD45RA-CD197+), and effector memory (CD45RA-CD197-) T-cell compartments. In addition, IL-7 facilitated activation of СD4- (but not CD4+) terminally differentiated effector (CD45RA+CD197-) Т cells. Finally, IL-7 was found to upregulate the production of IL-2, IFN-γ, IL-4, and IL-10 by activated T cells. In conclusion, we speculate that IL-7 is capable of enhancing functional T cell activity without causing significant functional inbalance between various T cell subsets.