Cerium Dioxide-Dextran Nanocomposites in the Development of a Medical Product for Wound Healing: Physical, Chemical and Biomedical Characteristics.

PURPOSE OF THE STUDY: the creation of a dextran coating on cerium oxide crystals using different ratios of cerium and dextran to synthesize nanocomposites, and the selection of the best nanocomposite to develop a nanodrug that accelerates quality wound healing with a new type of antimicrobial effect. MATERIALS AND METHODS: Nanocomposites were synthesized using cerium nitrate and dextran polysaccharide (6000 Da) at four different initial ratios of Ce(NO3)3x6H2O to dextran (by weight)-1:0.5 (Ce0.5D); 1:1 (Ce1D); 1:2 (Ce2D); and 1:3 (Ce3D). A series of physicochemical experiments were performed to characterize the created nanocomposites: UV-spectroscopy; X-ray phase analysis; transmission electron microscopy; dynamic light scattering and IR-spectroscopy. The biomedical effects of nanocomposites were studied on human fibroblast cell culture with an evaluation of their effect on the metabolic and proliferative activity of cells using an MTT test and direct cell counting. Antimicrobial activity was studied by mass spectrometry using gas chromatography-mass spectrometry against E. coli after 24 h and 48 h of co-incubation. RESULTS: According to the physicochemical studies, nanocrystals less than 5 nm in size with diffraction peaks characteristic of cerium dioxide were identified in all synthesized nanocomposites. With increasing polysaccharide concentration, the particle size of cerium dioxide decreased, and the smallest nanoparticles (<2 nm) were in Ce2D and Ce3D composites. The results of cell experiments showed a high level of safety of dextran nanoceria, while the absence of cytotoxicity (100% cell survival rate) was established for Ce2D and C3D sols. At a nanoceria concentration of 10-2 M, the proliferative activity of fibroblasts was statistically significantly enhanced only when co-cultured with Ce2D, but decreased with Ce3D. The metabolic activity of fibroblasts after 72 h of co-cultivation with nano composites increased with increasing dextran concentration, and the highest level was registered in Ce3D; from the dextran group, differences were registered in Ce2D and Ce3D sols. As a result of the microbiological study, the best antimicrobial activity (bacteriostatic effect) was found for Ce0.5D and Ce2D, which significantly inhibited the multiplication of E. coli after 24 h by an average of 22-27%, and after 48 h, all nanocomposites suppressed the multiplication of E. coli by 58-77%, which was the most pronounced for Ce0.5D, Ce1D, and Ce2D. CONCLUSIONS: The necessary physical characteristics of nanoceria-dextran nanocomposites that provide the best wound healing biological effects were determined. Ce2D at a concentration of 10-3 M, which stimulates cell proliferation and metabolism up to 2.5 times and allows a reduction in the rate of microorganism multiplication by three to four times, was selected for subsequent nanodrug creation.

Influence of the Synthesis Scheme of Nanocrystalline Cerium Oxide and Its Concentration on the Biological Activity of Cells Providing Wound Regeneration.

In the ongoing search for practical uses of rare-earth metal nanoparticles, cerium dioxide nanoparticles (nanoceria) have received special attention. The purpose of this research was to study the biomedical effects of nanocrystalline forms of cerium oxide obtained by different synthesis schemes and to evaluate the effect of different concentrations of nanoceria (from 10-2 to 10-6 M) on cells involved in the regeneration of skin cell structures such as fibroblasts, mesenchymal stem cells, and keratinocytes. Two different methods of nanoceria preparation were investigated: (1) CeO-NPs-1 by precipitation from aqueous solutions of cerium (III) nitrate hexahydrate and citric acid and (2) CeO-NPs-2 by hydrolysis of ammonium hexanitratocerate (IV) under conditions of thermal autoclaving. According to the X-ray diffraction, transmission electron microscopy, and dynamic light scattering data, CeO2-1 consists of individual particles of cerium dioxide (3-5 nm) and their aggregates with diameters of 60-130 nm. CeO2-2 comprises small aggregates of 8-20 nm in diameter, which consist of particles of 2-3 nm in size. Cell cultures of human fibroblasts, human mesenchymal stem cells, and human keratinocytes were cocultured with different concentrations of nanoceria sols (10-2, 10-3, 10-4, 10-5, and 10-6 mol/L). The metabolic activity of all cell types was investigated by MTT test after 48 and 72 h, whereas proliferative activity and cytotoxicity were determined by quantitative cell culture counting and live/dead test. A dependence of biological effects on the method of nanoceria preparation and concentration was revealed. Data were obtained with respect to the optimal concentration of sol to achieve the highest metabolic effect in the used cell cultures. Hypotheses about the mechanisms of the obtained effects and the structure of a fundamentally new medical device for accelerated healing of skin wounds were formulated. The method of nanoceria synthesis and concentration fundamentally and significantly change the biological activity of cell cultures of different types-from suppression to pronounced stimulation. The best biological activity of cell cultures was determined through cocultivation with sols of citrate nanoceria (CeO-NPs-1) at a concentration of 10-3-10-4 M.

The Role of Trace Elements and Minerals in Osteoporosis: A Review of Epidemiological and Laboratory Findings.

The objective of the present study was to review recent epidemiological and clinical data on the association between selected minerals and trace elements and osteoporosis, as well as to discuss the molecular mechanisms underlying these associations. We have performed a search in the PubMed-Medline and Google Scholar databases using the MeSH terms "osteoporosis", "osteogenesis", "osteoblast", "osteoclast", and "osteocyte" in association with the names of particular trace elements and minerals through 21 March 2023. The data demonstrate that physiological and nutritional levels of trace elements and minerals promote osteogenic differentiation through the up-regulation of BMP-2 and Wnt/ß-catenin signaling, as well as other pathways. miRNA and epigenetic effects were also involved in the regulation of the osteogenic effects of trace minerals. The antiresorptive effect of trace elements and minerals was associated with the inhibition of osteoclastogenesis. At the same time, the effect of trace elements and minerals on bone health appeared to be dose-dependent with low doses promoting an osteogenic effect, whereas high doses exerted opposite effects which promoted bone resorption and impaired bone formation. Concomitant with the results of the laboratory studies, several clinical trials and epidemiological studies demonstrated that supplementation with Zn, Mg, F, and Sr may improve bone quality, thus inducing antiosteoporotic effects.

AOX1a Expression in Arabidopsis thaliana Affects the State of Chloroplast Photoprotective Systems under Moderately High Light Conditions.

Alternative oxidase (AOX) in the mitochondrial electron transport chain is considered important for sustaining photosynthesis under high light conditions. Here, we examined the effects of the AOX pathway on the state of chloroplast photoprotective systems. Arabidopsis thaliana plants (4 weeks old), comprising three genotypes (wild type [WT], overexpressing [XX-2] and antisense [AS-12] lines for AOX1a), were exposed to moderately high light conditions (MHL, 400 µmol m-2 s-1) in a short-term experiment (8 h). After 8 h of MHL, the WT and XX-2 plants showed stable non-photochemical quenching (qN) and violaxanthin cycle activity. Antisense plants displayed the lowest level of qN and a lower de-epoxidation state (DEPS) relative to plants of the same line after 4-6 h MHL, as well as compared to WT and XX-2 plants after 8 h MHL. The decline in DEPS in AS-12 plants was attributed to an insufficient violaxanthin de-epoxidase activity, which in turn was associated with a decrease in reduced ascorbate levels in the chloroplasts and leaves. Simultaneously, gene expression and the activity of ascorbate peroxidase in the antisense line increased after 8 h of MHL, supporting the compensatory effect of the antioxidant system when AOX1a expression is suppressed. This study emphasizes the role played by AOX in modulating the photoprotection processes and in the maintenance of relationships between mitochondria and chloroplasts by influencing ascorbate content.

Early predictive blood markers of hemorrhagic stroke - influence of cytoflavin therapy.

Examination of the patterns of free-radical processes (FRP) and changes of the early screening markers to predict the course of hemorrhagic stroke (HS) and applied pathophysiologically based therapy can be of great practical importance. This study aimed to determine early changes in the parameters of oxidative stress and routine biochemistry blood tests in patients with HS and to assess their relationship with clinical outcome. The effects of early applied cytoflavin were also investigated. The prospective study included 151 patients with HS. Forty-eight percent of patients in the standard conservative therapy were given cytoflavin antioxidant energy therapy from the first day of hospitalization. The neurological status, neuroimaging, biochemical blood tests and FRP were assessed on days 1, 5, 10, and 20 of hospitalization. In patients with HS, an imbalance of all stages of FRP was detected proportionately to the severity of HS. The malondialdehyde concentration above 5.3 µmol/L, the number of leukocytes above 15 800, glucose above 11.9 mmol/L, lactate dehydrogenase above 574 IU/L, and lactate above 2.5 mmol/L, detected on the first day, predetermined a high risk of death. Additional cytoflavin treatment allowed stabilizing the clinical laboratory picture of HS, improved the treatment results, and reduced hospital mortality rate.

Efficacy of A Novel Smart Polymeric Nanodrug in the Treatment of Experimental Wounds in Rats.

High-quality and aesthetic wound healing, as well as effective medical support of this process, continue to be relevant. This study aims to evaluate the medical efficacy of a novel smart polymeric nanodrug (SPN) on the rate and mechanism of wound healing in experimental animals. The study was carried out in male Wistar rats (aged 8-9 months). In these animals, identical square wounds down to the fascia were made in non-sterile conditions on the back on both sides of the vertebra. SPN was used for the treatment of one wound, and the other wound was left without treatment (control group). Biocompatible citrate-stabilized cerium oxide nanoparticles integrated into a polysaccharide hydrogel matrix containing natural and synthetic polysaccharide polymers (pectin, alginate, chitosan, agar-agar, water-soluble cellulose derivatives) were used as the therapeutic agent. Changes in the wound sizes (area, volume) over time and wound temperature were assessed on Days 0, 1, 3, 5, 7, and 14. Histological examination of the wounds was performed on Days 3, 7, and 14. The study showed that the use of SPN accelerated wound healing in comparison with control wounds by inhibiting the inflammatory response, which was measured by a decreased number of white blood cells in SPN-treated wounds. It also accelerated the development of fibroblasts, with an early onset of new collagen synthesis, which eventually led to the formation of more tender postoperative scars. Thus, the study demonstrated that the use of SPN for the treatment of wounds was effective and promising.

Expression profiles of genes for mitochondrial respiratory energy-dissipating systems and antioxidant enzymes in wheat leaves during de-etiolation.

Mitochondrial respiratory components participate in the maintenance of chloroplast functional activity. This study investigates the effects 48h de-etiolation of spring wheat seedlings (Triticum aestivum L., var. Irgina) on the expression of genes that encode energy-dissipating respiratory components and antioxidant enzymes under continuous light conditions. The expression of AOX1a following the prolonged darkness exhibited a pattern indicating a prominent dependence on light. The expression of other respiratory genes, including NDA2, NDB2, and UCP1b, increased during de-etiolation and dark-to-light transition; however, changes in the expression of these genes occurred later than those in AOX1a expression. A high expression of NDA1 was detected after 12h of de-etiolation. The suppression of AOX1a, NDA2, NDB2, and UCP1b was observed 24h after de-etiolation when the photosynthetic apparatus and its defence systems against excess light were completely developed. The expression patterns of the respiratory genes and several genes encoding antioxidant enzymes (MnSOD, Cu-ZnSOD, t-APX, GR, and GRX) were quite similar. Our data indicate that the induction of nuclear genes encoding respiratory and antioxidant enzymes allow the plants to control reactive oxygen species (ROS) production and avoid oxidative stress during de-etiolation.