Effect of hypoxia on porphyrin metabolism in bone marrow mesenchymal stem cells.

Under hypoxic conditions, aminolevulinic acid-induced accumulation of porphyrin pigments and increase in heme content was observed in bone marrow mesenchymal stem cells. The expression of transferrin receptor CD71 responsible for Fe(2+) transport into the cell was also enhanced. Blockade of porphyrin-transporting protein ABCG2 with fumitremorgin C under conditions of normoxia and hypoxia induced accumulation of porphyrin pigments; in hypoxia, these changes were more pronounced.

[The influence of fibroblast growth factor (FGF2) on cardiomyocytes differentiation of mesenchymal stem cells of bone marrow ex vivo].

The influence of FGF2 on the efficiency of cardiomyocytes differentiation of mesenchymal stem cells (MSC) of bone marrow induced by 5-azacetidine (5-aza) was studied. The effect of FGF2 developing by the 14th day after the combined action of a differentiating agent and growth factor was manifested in an increase in Mef2A, Mef2D and gene transcription and a rise of ionized Ca2+ concentration in cytoplasm keeping cell viability and proliferation activity. In the presence of FGF2 this approach provided cardiomyogenesis and the increase in the formation of early precursors of cardiomyocytes.

[The process of heme synthesis in bone marrow mesenchymal stem cells cultured under fibroblast growth factor bFGF and hypoxic conditions].

It was demonstrated that fibroblast growth factor bFGF influences the process of heme synthesis, the proliferation activity and viability of bone marrow mesenchymal stem cells in culture under hypoxic conditions. The addition of fibroblast growth factor bFGF (7 ng/ml) to the medium under above conditions led to the accumulation of aminolevulinic acid--an early porphyrin and heme precursor, an increase in CD 71 expression--a transferrin receptor, and also a decrease in porphyrin pigments and heme contents--a late precursor and end products of heme synthesis, respectively. It was found that cultivation of the cells under hypoxic conditions and bFGF is an optimum to maintain high viability and proliferation capacity of the mesenchymal stem cells.

[Accumulation of porphyrins in cells of system of blood induced by 5-aminolaevulinic acid].

The levels and rates of accumulation of porphyrins in lymphoid cells and bone marrow cells treated with exogenous 5-aminolaevulinic acid (ALA) were studied. The dependence of the quantity of porphyrins accumulated in cell on ALA concentrations in the medium had maximum at 0.7-1.0 mM ALA for all the cell types studied (splenocytes, thymocytes, peripheral blood lymphocytes and bone marrow cells). The rate of accumulation of uro-, copro- and protoporphyrins depended on cell types. The lowest and the highest levels were found in splenocytes and highest in bone marrow cells respectively. It is suggested that photodynamic therapy employing ALA is potentially dangerous for blood cells.

[The influence of LIF (leukemia inhibitory factor) on the functional status of mouse line R1 embryonic stem cells].

The influence of cytokine LIF (Leukemia Inhibitory Factor) on the viability, and proliferation of mouse R1 line embryonic stem cells (ESC) and their distribution by cell cycle stages has been investigated. LIF (5-20 ng/ml) increased growth of colonies and maintained high proliferative and pluripotent properties of R1. LIF was also involved into the inhibition of spontaneous cell differentiation and apoptotic cell death; it also decreased the rations of S/G2+M cell cycle and doubling-time of cell population.

[Effect of the stem cell factor on the morphology and functional state of mouse embryonic stem cells].

The effect of the stem cell factor on the state of membranes and functional activity of mouse embryonic stem cells cultivated in LIF (Leukemia Inhibitory Factor) cytokine-free and LIF-containing media has been studied. It was shown that the stem cell factor induces changes in the viscosity of membrane lipid bilayer and increases the respiration rate, the ATP level, and the proliferation activity of embryonic stem cells. An intricate character of the LIF-dependent modification of biological effects of the stem cell factor was revealed.

[Impact of endogenous porphyrin-photosensitized exposure on peripheral lymphocytes in patients with pulmonary tuberculosis].

Peripheral lymphocytes (PL) were studied in 63 patients with pulmonary tuberculosis and 28 donors. The study revealed the elevated levels of lipid peroxidation products, altered membrane potential, and diminished PL viability in patients with pulmonary tuberculosis as compared with healthy donors. Analysis of the time dependences of cell viability and production of active tuberculosis products after endogenous porphyrin-photosensitized exposure suggests that the lymphocytes from patients with pulmonary tuberculosis are more exposed to the damaging effect of free radicals than the cells from healthy individuals. This is more apparent 18 hours of dark incubation after cell illumination in the presence of ALK-induced porphyrins in doses of 47.4 kJ/m2 or more. The findings suggest that the changes occurring in PL from patients with pulmonary tuberculosis may substantially cause immune disorders and contribute to the progression of a tuberculous process.

[Photodynamic inhibition of infection caused by herpes simplex virus type 1 in the cultured cells, by using 5-aminolevulinic acid-induced porphyrins].

On simulating infection caused by different herpes simplex virus type 1 (HSV-1) variants responsive and unresponsive to the drugs acyclovir and phosphonoacetic acid in the cultured Vero and C6 cells has revealed the higher ability of target cells to accumulate 5-aminolevulenic acid (ALA)-induced endogenous porphyrins, which determines the selectivity of their photo damages. Optimal conditions have been defined for all the studied HSV-1 variants to show a virus-inhibiting effect upon photodynamic exposure of infected and ALA-treated cell cultures.

Photodynamic inhibition of infection caused by drug-resistant variants of herpes simplex virus type I.

Membranotropic amphiphilic chromophore merocyanine 540 sensitized photodynamic inhibition of drug-resistant and sensitive variants of type I herpes simplex virus in cultured Vero cell. Optimal conditions of photodamage to virus particles and infected cells were determined (merocyanine 540 concentration 1 microM, illumination dose 32.5-65.0 kJ/m(2), exposure at early stages of infection). Infected cells actively bind the photosensitizer, which explains their selective photodamage.

Natural and probe fluorescence of lymphocytes of patients with pulmonary tuberculosis exposed to radiation as a result of the Chernobyl nuclear accident.

Parameters of natural and probe fluorescence of peripheral blood lymphocytes have been studied in 25 normal persons and 72 patients suffering from extensive forms of pulmonary tuberculosis who live in various radioecological conditions. It was found that in cell suspension the intensity of fluorescence of protein and the membrane-bound merocyanine 540 dye was 2.0-3.2 and 3.9-7.1 times higher, respectively, for the lymphocytes of the examined patients. For lymphocytes of the patients who live in radionuclide-contaminated areas fluorescence of reduced pyridine nucleotides and some fluorescent probes (ANS, DPGT, the ratio of eximer to monomer fluorescence of pyrene) and the merocyanine-photosensitized cell death were also found to increase. These can indicate some changes of cell membranes and reduction of the oxidation resistance of lymphocytes. There was not any substantial dependence on the changes in the parameters determined in the patients calculated radiation doses was revealed. It was found that biophysical tests, in particular, photosensitized cell death, are informative for estimation of severity of the tuberculous process and prognosis of its outcome in patients who live in adverse radioecological conditions.