Αnti-prion effects of anthocyanins

Prion diseases, also known as Transmissible Spongiform Encephalopathies (TSEs), are protein-based neurodegenerative disorders (NDs) affecting humans and animals. They are characterized by the conformational conversion of the normal cellular prion protein, PrPC, into the pathogenic isoform, PrPSc. Prion diseases are invariably fatal and despite ongoing research, no effective prophylactic or therapeutic avenues are currently available. Anthocyanins (ACNs) are unique flavonoid compounds and interest in their use as potential neuroprotective and/or therapeutic agents against NDs, has increased significantly in recent years. Therefore, we investigated the potential anti-oxidant and anti-prion effects of Oenin and Myrtillin, two of the most common anthocyanins, using the most accepted in the field overexpressing PrPScin vitro model and a cell free protein aggregation model. Our results, indicate both anthocyanins as strong anti-oxidant compounds, upregulating the expression of genes involved in the anti-oxidant response, and reducing the levels of Reactive Oxygen Species (ROS), produced due to pathogenic prion infection, through the activation of the Keap1-Nrf2 pathway. Importantly, they showcased remarkable anti-prion potential, as they not only caused the clearance of pathogenic PrPSc aggregates, but also completely inhibited the formation of PrPSc fibrils in the Cerebrospinal Fluid (CSF) of patients with Creutzfeldt-Jakob disease (CJD). Therefore, Oenin and Myrtillin possess pleiotropic effects, suggesting their potential use as promising preventive and/or therapeutic agents in prion diseases and possibly in the spectrum of neurodegenerative proteinopathies.

Effect of Modified Bioceramic Mineral Trioxide Aggregate Cement with Mesoporous Nanoparticles on Human Gingival Fibroblasts

The ion doping of mesoporous silica nanoparticles (MSNs) has played an important role in revolutionizing several materials applied in medicine and dentistry by enhancing their antibacterial and regenerative properties. Mineral trioxide aggregate (MTA) is a dental material widely used in vital pulp therapies with high success rates. The aim of this study was to investigate the effect of the modification of MTA with cerium (Ce)- or calcium (Ca)-doped MSNs on the biological behavior of human gingival fibroblasts (hGFs). MSNs were synthesized via sol-gel, doped with Ce and Ca ions, and mixed with MTA at three ratios each. Powder specimens were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Biocompatibility was evaluated using a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay following hGFs' incubation in serial dilutions of material eluates. Antioxidant status was evaluated using Cayman's antioxidant assay after incubating hGFs with material disc specimens, and cell attachment following dehydration fixation was observed through SEM. Material characterization confirmed the presence of mesoporous structures. Biological behavior and antioxidant capacity were enhanced in all cases with a statistically significant increase in CeMTA 50.50. The application of modified MTA with cerium-doped MSNs offers a promising strategy for vital pulp therapies.

Effect of silica-based mesoporous nanomaterials on human blood cells

Different mesoporous nanomaterials (MSNs) are constantly being developed for a range of therapeutic purposes, but they invariably interact with blood components and may cause hazardous side effects. Therefore, when designing and developing nanoparticles for biomedical applications, hemocompatibility should be one of the primary goals to assess their toxicity at the cellular level of all blood components. The aim of this study was to evaluate the compatibility of human blood cells (erythrocytes, platelets, and leukocytes) after exposure to silica-based mesoporous nanomaterials that had been manufactured using the sol-gel method, with Ca and Ce as doping elements. The viability of lymphocytes and monocytes was unaffected by the presence of MSNs at any concentration. However, it was found that all nanomaterials, at all concentrations, reduced the viability of granulocytes. P-selectin expression of all MSNs at all concentrations was statistically significantly higher in platelet incubation on the first day of storage (day 1) compared to the control. When incubated with MSNs, preserved platelets displayed higher levels of iROS at all MSNs types and concentrations examined. Ce-containing MSNs presented a slightly better hemocompatibility, although it was also dose dependent. Further research is required to determine how the unique characteristics of MSNs may affect various blood components in order to design safe and effective MSNs for various biomedical applications.

Oil from Mullet Roe Byproducts: Effect of Oil Extraction Method on Human Erythrocytes and Platelets

Background: The valorization of byproducts to obtain high nutritional value foods is of utmost importance for our planet where the population is booming. Among these products are oils rich in ω-3 fatty acids produced from fishery byproducts. Recently, mullet roe oil from roe byproducts was produced that was rich in the ω-3 fatty acids eicosatetraenoic acid (EPA) and docosahexaenoic acid (DHA). Oils are customarily characterized for their composition and degree of oxidation but little is known of their biological effects, especially the effect of the extraction method. Methods: The purpose of this study was to evaluate the effects of freshly extracted mullet roe oil from mullet roe byproducts and the effect of the extraction method on human red blood cells (hRBCs) and platelets. To this end, the hemocompatibility (cytotoxicity), oxidative effects, and erythrocyte membrane changes were examined after 1 and 24 h of incubation. Antiplatelet effects were also assessed in vitro. Results: The expeller press oil extraction method and alcalase-assisted extraction produced the most biocompatible oils, as shown by hemocompatibility measurements and the absence of erythrocyte membrane alterations. Solvent extracts and protease-assisted extraction oils resulted in the rupture of red blood cells at different examined dilutions, creating hemolysis. Conclusions: It seems that the proper functioning of oil-erythrocyte interactions cannot be explained solely by ROS. Further investigations combining chemical analysis with oil-cell interactions could be used as an input to design high nutritional value oils using green extraction technologies. All samples exhibited promising antiplatelet and antiblood clotting effects in vitro.

Study of Biological Behavior and Antimicrobial Properties of Cerium Oxide Nanoparticles

(1) Background: An element that has gained much attention in industrial and biomedical fields is Cerium (Ce). CeO2 nanoparticles have been proven to be promising regarding their different biomedical applications for the control of infection and inflammation. The aim of the present study was to investigate the biological properties and antimicrobial behavior of cerium oxide (CeO2) nanoparticles (NPs). (2) Methods: The investigation of the NPs' biocompatibility with human periodontal ligament cells (hPDLCs) was evaluated via the MTT assay. Measurement of alkaline phosphatase (ALP) levels and alizarine red staining (ARS) were used as markers in the investigation of CeO2 NPs' capacity to induce the osteogenic differentiation of hPDLCs. Induced inflammatory stress conditions were applied to hPDLCs with H2O2 to estimate the influence of CeO2 NPs on the viability of cells under these conditions, as well as to reveal any ROS scavenging properties. Total antioxidant capacity (TAC) of cell lysates with NPs was also investigated. Finally, the macro broth dilution method was the method of choice for checking the antibacterial capacity of CeO2 against the anaerobic pathogens Porphyromonas gingivalis and Prevotella intermedia. (3) Results: Cell viability assay indicated that hPDLCs increase their proliferation rate in a time-dependent manner in the presence of CeO2 NPs. ALP and ARS measurements showed that CeO2 NPs can promote the osteogenic differentiation of hPDLCs. In addition, the MTT assay and ROS determination demonstrated some interesting results concerning the viability of cells under oxidative stress conditions and, respectively, the capability of NPs to decrease free radical levels over the course of time. Antimicrobial toxicity was observed mainly against P. gingivalis. (4) Conclusions: CeO2 NPs could provide an excellent choice for use in clinical practices as they could prohibit bacterial proliferation and control inflammatory conditions.

Composite PLGA–Nanobioceramic Coating on Moxifloxacin-Loaded Akermanite 3D Porous Scaffolds for Bone Tissue Regeneration

Silica-based ceramics doped with calcium and magnesium have been proposed as suitable materials for scaffold fabrication. Akermanite (Ca2MgSi2O7) has attracted interest for bone regeneration due to its controllable biodegradation rate, improved mechanical properties, and high apatite-forming ability. Despite the profound advantages, ceramic scaffolds provide weak fracture resistance. The use of synthetic biopolymers such as poly(lactic-co-glycolic acid) (PLGA) as coating materials improves the mechanical performance of ceramic scaffolds and tailors their degradation rate. Moxifloxacin (MOX) is an antibiotic with antimicrobial activity against numerous aerobic and anaerobic bacteria. In this study, silica-based nanoparticles (NPs) enriched with calcium and magnesium, as well as copper and strontium ions that induce angiogenesis and osteogenesis, respectively, were incorporated into the PLGA coating. The aim was to produce composite akermanite/PLGA/NPs/MOX-loaded scaffolds through the foam replica technique combined with the sol–gel method to improve the overall effectiveness towards bone regeneration. The structural and physicochemical characterizations were evaluated. Their mechanical properties, apatite forming ability, degradation, pharmacokinetics, and hemocompatibility were also investigated. The addition of NPs improved the compressive strength, hemocompatibility, and in vitro degradation of the composite scaffolds, resulting in them keeping a 3D porous structure and a more prolonged release profile of MOX that makes them promising for bone regeneration applications.

Artemisinin Loaded Cerium-Doped Nanopowders Improved In Vitro the Biomineralization in Human Periodontal Ligament Cells

BACKGROUND

A promising strategy to enhance bone regeneration is the use of bioactive materials doped with metallic ions with therapeutic effects and their combination with active substances and/or drugs. The aim of the present study was to investigate the osteogenic capacity of human periodontal ligament cells (hPDLCs) in culture with artemisinin (ART)-loaded Ce-doped calcium silicate nanopowders (NPs); Methods: Mesoporous silica, calcium-doped and calcium/cerium-doped silicate NPs were synthesized via a surfactant-assisted cooperative self-assembly process. Human periodontal ligament cells (hPDLCs) were isolated and tested for their osteogenic differentiation in the presence of ART-loaded and unloaded NPs through alkaline phosphatase (ALP) activity and Alizarine red S staining, while their antioxidant capacity was also evaluated; Results: ART promoted further the osteogenic differentiation of hPDLCs in the presence of Ce-doped NPs. Higher amounts of Ce in the ART-loaded NPs inversely affected the mineral deposition process by the hPDLCs. ART and Ce in the NPs have a synergistic role controlling the redox status and reducing ROS production from the hPDLCs; Conclusions: By monitoring the Ce amount and ART concentration, mesoporous NPs with optimum properties can be developed towards bone tissue regeneration demonstrating also potential application in periodontal tissue regeneration strategies.

A world free of malaria: It is time for Africa to actively champion and take leadership of elimination and eradication strategies

The global burden of malaria seems unabated. Africa carries the greatest burden accounting for over 95% of the annual cases of malaria. For the vision of a world free of malaria by Global Technical Strategy to be achieved, Africa must take up the stakeholder's role. It is therefore imperative that Africa rises up to the challenge of malaria and champion the fight against it. The fight against malaria may just be a futile or mere academic venture if Africans are not directly and fully involved. This work reviews the roles playable by Africans in order to curb the malaria in Africa and the world at large.

The Role of Equilibrium between Free Radicals and Antioxidants in Depression and Bipolar Disorder

Background: Increasing evidence suggests that the presence of oxidative stress and disorders of the antioxidant defense system are involved in a wide range of neuropsychiatric disorders, such as bipolar disorder, schizophrenia and major depression, but the exact mechanism remains unknown. This review focuses on a better appreciation of the contribution of oxidative stress to depression and bipolar disorder. Methods: This review was conducted by extracting information from other research and review studies, as well as other meta-analyses, using two search engines, PubMed and Google Scholar. Results: As far as depression is concerned, there is agreement among researchers on the association between oxidative stress and antioxidants. In bipolar disorder, however, most of them observe strong lipid peroxidation in patients, while regarding antioxidant levels, opinions are divided. Nevertheless, in recent years, it seems that on depression, there are mainly meta-analyses and reviews, rather than research studies, unlike on bipolar disorder. Conclusions: Undoubtedly, this review shows that there is an association among oxidative stress, free radicals and antioxidants in both mental disorders, but further research should be performed on the exact role of oxidative stress in the pathophysiology of these diseases.

A Preliminary Study about the Role of Reactive Oxygen Species and Inflammatory Process after COVID-19 Vaccination and COVID-19 Disease

During the last couple of critical years, worldwide, there have been more than 550 million confirmed cases of COVID-19, including more than 6 million deaths (reported by the WHO); with respect to these cases, several vaccines, mainly mRNA vaccines, seem to prevent and protect from SARS-CoV-2 infection. We hypothesize that oxidative stress is one of the key factors playing an important role in both the generation and development of various kinds of disease, as well as antibody generation, as many biological paths can generate reactive oxygen species (ROS), and cellular activities can be modulated when ROS/antioxidant balance is interrupted. A pilot study was conducted in two stages during the COVID-19 pandemic in 2021 involving 222 participants between the ages of 26 and 66 years. ROS levels were measured before an after vaccination in the blood samples of 20 individuals who were vaccinated with two doses of mRNA vaccine, and an increase in ROS levels was observed after the first dose, with no modifications observed until the day before the second vaccination dose. A statistically significant difference (p < 0.001) was observed between time points 3 and 4 (before and after second dose), when participants were vaccinated for the second time, and ROS levels decreased from 21,758 to 17,580 a.u. In the second stage, blood was collected from 28 participants 45 days after COVID-19 infection (Group A), from 131 participants 45 days after receiving two doses of mRNA vaccine against COVID-19 (Group B), and from 13 healthy individuals as a control group (Group C). Additionally, antibodies levels were measured in all groups to investigate a possible correlation with ROS levels. A strong negative correlation was found between free radicals and disease antibodies in Group A (r = −0.45, p = 0.001), especially in the male subgroup (r = −0.88, p = 0.001), as well as in the female subgroup (r = −0.24, p < 0.001). Furthermore, no significant correlation (only a negative trend) was found with antibodies derived from vaccination in Group B (r = −0.01), and a negative trend was observed in the female subgroup, whereas a positive trend was observed in the male subgroup.

The Clinical Utility of ABO and RHD Systems as Potential Indicators of Health Status, a Preliminary Study in Greek Population

Objective: The objective of this study is to further highlight the differences between different ABO blood groups and Rhesus types with health biomarkers. Methods: In total 150 active healthy blood donors participated in our study comprising of 80 males from 19–61 years and 70 females aged from 21 to 64. Participants carrying blood group A were 55 individuals, blood group B 32, blood group O 51, and blood group AB 12, RHD+ 132, and RHD- 18. All the volunteer regular blood donors were selected recognizing them as a healthy population excluding drug and supplements intake. Their blood samples were analyzed just before blood donation for biochemical, hematological, and antioxidant markers. Statistical computations were performed using the SPSS tool, specifically, the one-way ANOVA test, Chi-square statistics, and logistic regression were used as statistical models. Results: O blood donors presented better iron absorption and the worst lipid profile. Indeed, a significant trend of high atheromatic index values revealed an increased risk for hyperlipidemia, in contrast with blood group A presenting a better lipid profile with lower atheromatic index values. There was also a gender related association for blood group A compared with O that was further highlighted using binary logistic regression. Conclusion: In this study, a significant difference was observed among the ABO blood groups in several of the examined biochemical and hematological biomarkers. O blood group appeared different behavior in comparison to all the tested blood groups and furthermore the RHD-group presented a better lipid profile in comparison to the RHD+ group. In order to obtain a more comprehensive view of the correlation between the ABO blood group and biochemical markers, further studies are required.

Resistance to artemisinin in falciparum malaria parasites: A redox-mediated phenomenon

Malaria remains a major public health disease due to its high yearly mortality and morbidity. Resistance to the gold standard drug, artemisinin, is worrisome and needs better understanding in order to be overcome. In this work, we sought to study whether redox processes are involved in artemisinin resistance. As artemisinin is known to act among others via production of reactive species, we first compared the production of reactive oxygen species and concomitant protein oxidation in artemisinin-sensitive and artemisinin-resistant parasites when treated with artemisinin. The results undoubtedly demonstrated, using different original methods, that the level of ROS, including superoxide production, and oxidized protein were lower in the resistant strain. Interestingly, the major in-between strain difference was reported at the earlier ring stages, which are the forms able to enter in a quiescence state according to the ART resistance phenomenon. Moreover, we demonstrated a better homeostasis regulation in relation with higher expression of antioxidants in the artemisinin-resistant parasites than their sensitive counterparts after artemisinin exposure, notably, superoxide dismutase and the glutathione (GSH) system. These findings enrich the body of knowledges about the multifaceted mechanism of artemisinin resistance and will help in the design and development of newer antimalarials strategies active against resistant parasites.

In Vitro and In Silico Antimalarial Evaluation of FM-AZ, a New Artemisinin Derivative

Artemisinin-based Combination Therapies (ACTs) are currently the frontline treatment against Plasmodium falciparum malaria, but parasite resistance to artemisinin (ART) and its derivatives, core components of ACTs, is spreading in the Mekong countries. In this study, we report the synthesis of several novel artemisinin derivatives and evaluate their in vitro and in silico capacity to counteract Plasmodium falciparum artemisinin resistance. Furthermore, recognizing that the malaria parasite devotes considerable resources to minimizing the oxidative stress that it creates during its rapid consumption of hemoglobin and the release of heme, we sought to explore whether further augmentation of this oxidative toxicity might constitute an important addition to artemisinins. The present report demonstrates, in vitro, that FM-AZ, a newly synthesized artemisinin derivative, has a lower IC₅₀ than artemisinin in P. falciparum and a rapid action in killing the parasites. The docking studies for important parasite protein targets, PfATP6 and PfHDP, complemented the in vitro results, explaining the superior IC₅₀ values of FM-AZ in comparison with ART obtained for the ART-resistant strain. However, cross-resistance between FM-AZ and artemisinins was evidenced in vitro.

The Potential Impact of Blood System on Dietary Habits and Smoking

The ‘Blood-Type’ diet advises individuals to eat according to their ABO blood group to improve their health and decrease the risk of chronic diseases. However, the food preferences of individuals with different blood groups have not been examined. The aim of our study was to investigate, in healthy regular blood donors (rBDs), the associations of smoke, alcohol, caffeine, vitamin and fat intake with their different blood groups and if ABO groups could be a potential predictor tool for disease prevention. A total of 329 volunteers were divided into four groups according to their ABO types: Group 1 (A) comprised 141 rBDs; Group 2 (B), 65 rBDs; Group 3 (O), 96 rBDs; and Group 4, 27 rBDs. Additionally, they were divided into two groups according to their rhesus types and their preferences for smoke, too. Dietary intake was assessed using 3-day food recall and the Food Processor computer program for nutrient analysis. Alcohol, caffeine, sugar and Vitamin D consumption were significantly (p < 0.05) higher in the O group. The A group presented statistically significantly (p < 0.05) greater preferences for cholesterol intake and a higher trend for smoking (25%) habits compared with all the other groups, whereas Group B preferred more fatty foods. The blood group AB appeared to be the most controlled food intake group. Regarding the rhesus comparisons, alcohol; caffeine; and Vitamin C, D, E and K consumptions were significantly (p < 0.05) higher in rhesus-positive individuals than their rhesus-negative counterparts. For the non-smoker group, compared with the smokers, a higher consumption of Vitamin D and fibers was found. In conclusion, in the present study, statistically significant correlations of the ABO and rhesus system with some dietary parameters were found, indicating a consequent influence of these preferences on the progression of different diseases.

Impact of Drug Pressure versus Limited Access to Drug in Malaria Control: The Dilemma

Malaria burden has severe impact on the world. Several arsenals, including the use of antimalarials, are in place to curb the malaria burden. However, the application of these antimalarials has two extremes, limited access to drug and drug pressure, which may have similar impact on malaria control, leading to treatment failure through divergent mechanisms. Limited access to drugs ensures that patients do not get the right doses of the antimalarials in order to have an effective plasma concentration to kill the malaria parasites, which leads to treatment failure and overall reduction in malaria control via increased transmission rate. On the other hand, drug pressure can lead to the selection of drug resistance phenotypes in a subpopulation of the malaria parasites as they mutate in order to adapt. This also leads to a reduction in malaria control. Addressing these extremes in antimalarial application can be essential in maintaining the relevance of the conventional antimalarials in winning the war against malaria.

Effects of Greek Honey and Propolis on Oxidative Stress and Biochemical Parameters in Regular Blood Donors

Background and objectives: Honey products contain a lot of compounds, such as vitamins, enzymes, and minerals, which make honey and its products a great antioxidant with a critical role in health status. It is well accepted that honey and propolis can improve a lot of health problems when they are consumed in certain quantities. The objective of this study is to help regular blood donors improve their health status after donation. Material and methods: Eighty regular blood donor volunteers—30 males aged 19–61 and 30 females aged 21–64—were divided into 4 groups: group A (n = 20) consumed 2 spoons of Greek honey and 1 drop of propolis per day for 1 month, group B (n = 20) consumed 2 spoons of honey per day for 1 month, group C (n = 20) consumed 1 drop of propolis per day, and group D (n = 20) did not consume any Greek honey products. Blood samples were collected from all participants just before the consumption of the products, one month after the consumption, and six months after honey product consumption had ceased. All samples were analyzed for reactive oxygen species (ROS), lipid profiles, and ferritin levels. Results: The ROS were significantly (p < 0.05) lower in groups A, B, and C after the honey product consumption and increased significantly again after six months. No significant differences in lipid profiles were observed. Only triglyceride levels were increased after six months in all groups. On the other hand, ferritin levels were not statistically significantly decreased after six months in groups A and B, while they were increased in group C. Conclusions: In the present study, statistically significant decreases in ROS status was found after a small dose of honey product consumption, indicating a diet with an extra small dose of honey products after blood donation.

Effect of Silica Based Nanoparticles against Plasmodium falciparum and Leishmania infantum parasites

Malaria and Leishmaniasis are two major parasitic diseases, endemic in large areas of tropical countries with high morbidity and mortality across the world. Nanoparticles in small sizes are specifically considered in medicine due to their ability to enter the cells, control the distribution of the administered drug and carry the drug specifically to the place of action. The present study aims to introduce the application of silica nanoparticles as new promising nanotools in malaria and leishmaniasis treatment. Ion doped silica nanomaterials revealed antileishmanial activities indicating the positive role of calcium, magnesium and copper to the surface of the particles against Leishmania parasites. Artemisinin-loaded nanoparticles presented the most promising antiparasitic properties with a sustained release able to overcome the parasite invasion. The sustainable release of artemisinin guarantee both the maintenance of its potential efficacy and also introduce an administration of drug to avoid subsequent drug resistance.

Sol-Gel Synthesis and Characterization of YSZ Nanofillers for Dental Cements at Different Temperatures

BACKGROUND

Yttria-stabilized zirconia nanoparticles can be applied as fillers to improve the mechanical and antibacterial properties of luting cement. The aim of this study was to synthesize yttria-stabilized zirconia nanoparticles by the sol-gel method and to investigate their composition, structure, morphology and biological properties.

METHODS

Nanopowders of ZrO₂ 7 wt% Y₂O₃ (nY-ZrO) were synthesized by the sol-gel method and were sintered at three different temperatures: 800, 1000 and 1200 °C, and their composition, size and morphology were investigated. The biocompatibility was investigated with human gingival fibroblasts (hGFs), while reactive oxygen species (ROS) production was evaluated through fluorescence analysis.

RESULTS

All synthesized materials were composed of tetragonal zirconia, while nanopowders sintered at 800 °C and 1000 °C additionally contained 5 and 20 wt% of the cubic phase. By increasing the calcination temperature, the crystalline size of the nanoparticles increased from 12.1 nm for nY-ZrO800 to 47.2 nm for nY-ZrO1200. Nano-sized particles with good dispersion and low agglomeration were received. Cell culture studies with human gingival fibroblasts verified the nanopowders' biocompatibility and their ROS scavenging activity.

CONCLUSIONS

the obtained sol-gel derived nanopowders showed suitable properties to be potentially used as nanofillers for dental luting cement.

Superoxide: A major role in the mechanism of action of essential antimalarial drugs

Understanding the mode of action of antimalarials is central to optimizing their use and the discovery of new therapeutics. Currently used antimalarials belong to a limited series of chemical structures and their mechanisms of action are coutinuously debated. Whereas the involvement of reactive species that in turn kill the parasites sensitive to oxidative stress, is accepted for artemisinins, little is known about the generation of such species in the case of quinolines or hydroxynaphtoquinone. Moreover, the nature of the reactive species involved has never been characterized in Plasmodium-infected erythrocytes. The aim of this work was to determine and elucidate the production of the primary radical, superoxide in Plasmodium-infected erythrocytes treated with artemisinin, dihydroartemisinin, chloroquine and atovaquone, as representatives of three major classes of antimalarials. The intracellular generation of superoxide was quantified by liquid chromatography coupled to mass spectrometry (LC-MS). We demonstrated that artemisinins, atovaquone and to a lesser extent chloroquine, generate significant levels of superoxide radicals in Plasmodium falciparum sensitive strains. More so, the production of superoxide was lowered in chloroquine-resistant strain of Plasmodium treated with chloroquine. These results consolidate the knowledge about the mechanism of action of these different antimalarials and should be taken into consideration in the design of future drugs to fight drug-resistant parasites.

Synthesis and Characterization of Mesoporous Mg- and Sr-Doped Nanoparticles for Moxifloxacin Drug Delivery in Promising Tissue Engineering Applications

Mesoporous silica-based nanoparticles (MSNs) are considered promising drug carriers because of their ordered pore structure, which permits high drug loading and release capacity. The dissolution of Si and Ca from MSNs can trigger osteogenic differentiation of stem cells towards extracellular matrix calcification, while Mg and Sr constitute key elements of bone biology and metabolism. The aim of this study was the synthesis and characterization of sol-gel-derived MSNs co-doped with Ca, Mg and Sr. Their physico-chemical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF), Brunauer Emmett Teller and Brunauer Joyner Halenda (BET/BJH), dynamic light scattering (DLS) and ζ-potential measurements. Moxifloxacin loading and release profiles were assessed with high performance liquid chromatography (HPLC) cell viability on human periodontal ligament fibroblasts and their hemolytic activity in contact with human red blood cells (RBCs) at various concentrations were also investigated. Doped MSNs generally retained their textural characteristics, while different compositions affected particle size, hemolytic activity and moxifloxacin loading/release profiles. All co-doped MSNs revealed the formation of hydroxycarbonate apatite on their surface after immersion in simulated body fluid (SBF) and promoted mitochondrial activity and cell proliferation.

The potential antimalarial efficacy of hemocompatible silver nanoparticles from Artemisia species against P. falciparum parasite

Malaria represents one of the most common infectious diseases which becoming an impellent public health problem worldwide. Antimalarial classical medications include quinine-based drugs, like chloroquine, and artesunate, a derivative of artemisinin, a molecule found in the plant Artemisia annua. Such therapeutics are very effective but show heavy side effects like drug resistance. In this study, "green" silver nanoparticles (AgNPs) have been prepared from two Artemisia species (A. abrotanum and A. arborescens), traditionally used in folk medicine as a remedy for different conditions, and their potential antimalarial efficacy have been assessed. AgNPs have been characterized by UV-Vis, dynamic light scattering and zeta potential, FTIR, XRD, TEM and EDX. The structural characterization has demonstrated the spheroidal shape of nanoparticles and dimensions under 50 nm, useful for biomedical studies. Zeta potential analysis have shown the stability and dispersion of green AgNPs in aqueous medium without aggregation. AgNPs hemocompatibility and antimalarial activity have been studied in Plasmodium falciparum cultures in in vitro experiments. The antiplasmodial effect has been assessed using increasing doses of AgNPs (0.6 to 7.5 μg/mL) on parasitized red blood cells (pRBCs). Obtained data showed that the hemocompatibility of AgNPs is related to their synthetic route and depends on the administered dose. A. abrotanum-AgNPs (1) have shown the lowest percentage of hemolytic activity on pRBCs, underlining their hemocompatibility. These results are in accordance with the lower levels of parasitemia observed after A. abrotanum-AgNPs (1) treatment respect to A. arborescens-AgNPs (2), and AgNPs (3) derived from a classical chemical synthesis. Moreover, after 24 and 48 hours of A. abrotanum-AgNPs (1) treatment, the parasite growth was locked in the ring stage, evidencing the effect of these nanoparticles to hinder the maturation of P. falciparum. The anti-malarial activity of A. abrotanum-AgNPs (1) on pRBCs was demonstrated to be higher than that of A. arborescens-AgNPs (2).

Syk Kinase Inhibitors Synergize with Artemisinins by Enhancing Oxidative Stress in Plasmodium falciparum-Parasitized Erythrocytes

Although artemisinin-based combination therapies (ACTs) treat Plasmodium falciparum malaria effectively throughout most of the world, the recent expansion of ACT-resistant strains in some countries of the Greater Mekong Subregion (GMS) further increased the interest in improving the effectiveness of treatment and counteracting resistance. Recognizing that (1) partially denatured hemoglobin containing reactive iron (hemichromes) is generated in parasitized red blood cells (pRBC) by oxidative stress, (2) redox-active hemichromes have the potential to enhance oxidative stress triggered by the parasite and the activation of artemisinin to its pharmaceutically active form, and (3) Syk kinase inhibitors block the release of membrane microparticles containing hemichromes, we hypothesized that increasing hemichrome content in parasitized erythrocytes through the inhibition of Syk kinase might trigger a virtuous cycle involving the activation of artemisinin, the enhancement of oxidative stress elicited by activated artemisinin, and a further increase in hemichrome production. We demonstrate here that artemisinin indeed augments oxidative stress within parasitized RBCs and that Syk kinase inhibitors further increase iron-dependent oxidative stress, synergizing with artemisinin in killing the parasite. We then demonstrate that Syk kinase inhibitors achieve this oxidative enhancement by preventing parasite-induced release of erythrocyte-derived microparticles containing redox-active hemichromes. We also observe that Syk kinase inhibitors do not promote oxidative toxicity to healthy RBCs as they do not produce appreciable amounts of hemichromes. Since some Syk kinase inhibitors can be taken daily with minimal side effects, we propose that Syk kinase inhibitors could evidently contribute to the potentiation of ACTs.

Relationship between dietary fats and serum antioxidants with atheromatic index in regular blood donors

BACKGROUND & OBJECTIVES

Nutritional choices, which include dietary fatty acids (FA), vitamins and sugars, have an important significant impact on the development of atheromatic index levels. Controversial opinions exist in the literature regarding the role of different fat types and their association with atheromatic index. We investigated the relationship between dietary intake with different atheromatic index groups of volunteer regular blood donors (rBDs) recognizing them as a healthy population excluding drug and supplements intake and we correlated their values with serum total antioxidant status (sTAS).

MATERIAL & METHODS

150 individuals used in this study were divided in 3 groups according to their atheromatic index (AI = Total cholesterol/HDL) (AI): Group 1 (AI < 3.5) comprised of 50 rBDs, Group 2 (AI 3.5-4.49) of 52 rBDs and Group 3 of 48 rBDs (AI > 4.5). Dietary intake was assessed using the 3 day food recall and the Food Processor, computer program for nutrient analysis. sTAS was measured in all samples and correlated with atheromatic index too.

RESULTS

Our study showed that rBDs with low dietary intake of all vitamins, Ω3 fatty acids, trans fatty acids and dietary cholesterol presented an increased atheromatic index. On the other hand rBDs with high dietary intake of saturated fat, total fats, monounsaturated and polyunsaturated fats and sugar showed increased atheromatic index. In addition, groups with the higher atheromatic index presented statistically significant higher total antioxidant status. Trans FA are also positively associated with sTAS and on the other hand dietary cholesterol is negatively associated with sTAS and positively in groups B and C.

CONCLUSIONS

The results of the present study showed that dietary intake of different types of fatty acids should be used separately as atheromatic index predictors. Moreover, sTAS is correlated with dietary intake of SFA, MUFA, PUFA, Cholesterol, Trans FA and sugar. Finally, the measurement of each fatty acid would be of great value for the screening of lipid metabolism disorders in atheromatic index control.

Oxidation of Erythrocytes Enhance the Production of Reactive Species in the Presence of Artemisinins

In red blood cells, hemoglobin iron represents the most plausible candidate to catalyze artemisinin activation but the limited reactivity of iron bound to hemoglobin does not play in favor for its direct involvement. Denatured hemoglobin appears a more likely candidate for artemisinin redox activation because it is expected to contain reactive iron and it has been described to release free heme and/or iron in erythrocyte. The aim of our study is to investigate, using three different methods: fluorescence, electron paramagnetic resonance and liquid chromatography coupled to mass spectrometry, how increasing the level of accessible iron into the red blood cells can enhance the reactive oxygen species (ROS) production derived from artemisinin. The over-increase of iron was achieved using phenylhydrazine, a strong oxidant that causes oxidative stress within erythrocytes, resulting in oxidation of oxyhemoglobin and leading to the formation of methemoglobin, which is subsequently converted into irreversible hemichromes (iron (III) compounds). Our findings confirmed, using the iron III chelator, desferrioxamine, the indirect participation of iron (III) compounds in the activation process of artemisinins. Furthermore, in strong reducing conditions, the activation of artemisinin and the consequent production of ROS was enhanced. In conclusion, we demonstrate, through the measurement of intra-erythrocytic superoxide and hydrogen peroxide production using various methods, that artemisinin activation can be drastically enhanced by pre-oxidation of erythrocytes.

Effect of Sintering Temperature of Bioactive Glass Nanoceramics on the Hemolytic Activity and Oxidative Stress Biomarkers in Erythrocytes

INTRODUCTION

The nature of the surface is critical in determining the biological activity of silica powders. A novel correlation between toxicity and surface properties of bioactive glass ceramics (BGCs) synthesized via the sol-gel method was attempted in this study.

METHODS

The behavior of BGCs after their attachment to the surface of red blood cells (RBCs) was evaluated and their toxic effects were determined based on hemolysis, membrane injury via anti-phosphotyrosine immunoblot of Band 3, lipid peroxidation, potential to generate reactive oxygen species, and antioxidant enzyme production. In particular, three BGCs were synthesized and treated at three sintering temperatures (T1 = 835 °C, T2 = 1000 °C and T3 = 1100 °C) to investigate possible relation between surface charge or structure and hemolytic potential.

RESULTS

Their toxicity based on hemolysis was dose dependent, while BGC-T2 had the best hemocompatibility in compare with the other BGCs.No BGCs in dosages lower than 0.125 mg/mL could damage erythrocytes. On the other hand, all BGCs promoted the production of reactive oxygen species in certain concentrations, with the BGC-T2 producing the lowest ROS and increasing the glutathione levels in RBCs protecting their damage.

CONCLUSIONS

The results suggest that various factors such as size, a probable different proportion of surface silanols, a balanced mechanism between calcium and magnesium cellular uptake or the different crystalline nature may have contributed to this finding; however, future research is needed to clarify the underlying mechanisms.

An LC-MS Assay to Measure Superoxide Radicals and Hydrogen Peroxide in the Blood System

Red blood cells are constantly exposed to reactive species under physiological or pathological conditions or during administration of xenobiotics. Regardless of the source, its accurate quantification is paramount in the area of theragnostics, which had been elusive up until now. Even if there are a lot of approaches to evaluate the oxidative stress, very sensitive methods are missing for the blood system. We therefore sought to apply a highly sensitive approach, by liquid chromatography coupled to mass spectrometry (UPLC–MS), for the quantification of reactive species such as superoxide radical and hydrogen peroxide using dihydroethidium (DHE) and coumarin boronic acid (CBA) probes respectively through the detection of 2-hydroxyethidium (2OH-E⁺) and 7-hydroxycoumarin (COH). The use of the high-resolution mass spectrometry associated to UPLC ensured a selective detection of superoxide and hydrogen peroxide in the blood system under diverse conditions such as oxidized red blood cells (RBCs), untreated and treated parasitized RBCs. Moreover, this technique allowed the determination of reactive species in human plasma. This protocol provides a huge opportunity for in-depth study of several pathological conditions vis-a-vis their treatment in modern medicine.

Effect of ion doping in silica-based nanoparticles on the hemolytic and oxidative activity in contact with human erythrocytes

AIM

The aim of this study was the synthesis of ion doped silica-based nanoparticles and the evaluation of their toxic effect on erythrocytes.

MATERIALS & METHODS

Their synthesis was performed using the sol-gel method, by the progressive addition of calcium, magnesium and copper ions on pure silica nanoparticles. The toxicity evaluation was based on hemolysis, lipid peroxidation, ROS, H₂O₂ species and antioxidant enzyme production.

RESULTS

The addition of Mg and Cu in the SNs presented better hemocompatibility by protecting erythrocytes from oxidative stress.

CONCLUSION

Ion doping with magnesium in the investigated calcium silicate system induces a protective effect in erythrocyte membrane in compare with pure silica nanoparticles.

Hematological, biochemical and antioxidant indices variations in regular blood donors among Mediterranean regions

BACKGROUND & OBJECTIVES

One of the most important problems in Mediterranean regions is finding blood donors to overcome the high need of its population. Understanding the health benefits of blood donation frequency will activate more volunteers to donate. The aim of this study variations of hematological and biochemical indices in regular male and female donors from Greece and Italy METHODS: A cross-sectional study consisted of 350 voluntary blood donors (VDs)was conducted in two mediterranean Blood Banks, Greece and Italy. The first one from the General Hospital of Naousa, Greece on samples of 90 regular and 60 first-time blood donors. The second one from AOU Sassari, Sardinia, Italy on convenient samples of 100 first-time samples and 100 regular blood donors. Donors' particulars were obtained from blood bank records. The hematological and biochemical parameters were determined for all donors and Total Antioxidant Status (TAS) only for greek VDs.

RESULTS

High frequency blood donation of Greek VDs could be associated with evidence of reduction of body iron stores, reduced oxidative stress and improvement of liver function biomarkers in regular groups. Interestingly, Sardinian regular male VDs presented increased iron stores in compare with the first time VDs. In both Mediterranean populations (Greeks and Italians) the lipid profile of the female regular blood donors has been improved in compare with the first timers.

CONCLUSION

Regular blood donation increases antioxidant capacity and affects positively the hematological parameters and biochemical biomarkers in donors. Gender plays an important role in relation to all hematological and biochemical parameters. Further studies in larger population should evaluate the beneficial-effect of blood donation and promote people to donate more frequent.

Effect of ethanol/TEOS ratios and amount of ammonia on the properties of copper-doped calcium silicate nanoceramics

Calcium magnesium silicate glasses could be suggested for the synthesis of scaffolds for hard tissue regeneration, as they present a high residual glassy phase, high hardness values and hydroxyapatite-forming ability. The use of trace elements in the human body, such as Cu, could improve the biological performance of such glasses, as Cu is known to play a significant role in angiogenesis. Nano-bioceramics are preferable compared to their micro-scale counterparts, because of their increased surface area, which improves both mechanical properties and apatite-forming ability due to the increased nucleation sites provided, their high diffusion rates, reduced sintering time or temperature, and high mechanical properties. The aim of the present work was the evaluation of the effect of different ratios of Ethanol/TEOS and total amount of the inserted ammonia to the particle size, morphology and bioactive, hemolytic and antibacterial behavior of nanoparticles in the quaternary system SiO₂-CaO-MgO-CuO. Different ratios of Ethanol/TEOS and ammonia amount affected the size and morphology of bioactive nanopowders. The optimum materials were synthesized with the highest ethanol/TEOS ratio and ammonia amount as verified by the enhanced apatite-forming ability and antibacterial and non-hemolytic properties.

Correlation of Oxidative Stress Biomarkers and Hematological Parameters in Blood Cancer Patients from Sardinia, Italy

Background: Over the last few decades, there has been a dramatic increase in hematological malignancies (HMs) in the population of Sardinia. It is accepted that oxidative stress biomarkers have been demonstrated to be prognostically important in various neoplastic diseases. The aim of this study is to evaluate serum vitamin E, total antioxidant capacity (TAC), Malondialdehyde (MDA) and reactive oxygen species (ROS) levels in 80 Sardinian patients with different HMs [acute myeloid leukemia (AML)(n=20), myelodysplastic syndromes (MDS) (n=20), Hodgkin lymphoma (HL) (n=20) and non-Hodgkin lymphoma (NHL) (n=20)] on the day of their diagnosis. Materials and Methods: Samples from all participants were obtained after an overnight fast (at least 10 hours). This study was approved and conducted in accordance with Good Clinical Practice guidelines and the Declaration of Helsinki. Patients and controls provided written, informed consent before entering the study. All study participants’ medical history and their medication were documented upon enrolling. Results: Lower levels of TAC and Vitamin E were observed in most of the studied groups compared to healthy controls (0.41-0.49 mmol/L vs. 0.56 mmol/L) (19.55-28.55 μmol/L vs. 34.51 μmol/L). Moreover, higher average MDA levels were observed in HL and NHL patients compared to healthy controls (16.6 ng/ml-17.8 ng/ml vs. 7.4 ng/ml). Additionally, the ROS values of all studied groups were found elevated. Serum TAC showed significant negative correlations with MDA values (R= -0.51; P<0.001). Statistical significance was observed in all hematological parameters, producing either positive or negative correlation with at least one OS biomarker. Conclusion: The present data suggest that Sardinian patients with HL and NHL on the day of their diagnosis presented the highest OS in comparison to AML and healthy subjects. Moreover, MDS patients presented high OS status. Likewise, our results also indicated that changes in their hematological indices are eminent of their oxidative and antioxidative status.

Clinical impact of the two ART resistance markers, K13 gene mutations and DPC3 in Vietnam

Background

In Vietnam, a rapid decline of P. falciparum malaria cases has been documented in the past years, the number of Plasmodium falciparum malaria cases has rapidly decreased passing from 19.638 in 2012 to 4.073 cases in 2016. Concomitantly, the spread of artemisinin resistance markers is raising concern on the future efficacy of the ACTs. An evaluation of the clinical impact of the artemisinin resistance markers is therefore of interest.

Methods

The clinical effectiveness of dihydroartemisinin-piperaquine therapy (DHA-PPQ) has been evaluated in three districts characterized by different rates of ART resistance markers: K13(C580Y) mutation and delayed parasite clearance on day 3 (DPC3). Patients were stratified in 3 groups a) no markers, b) one marker (suspected resistance), c) co-presence of both markers (confirmed resistance). In the studied areas, the clinical effectiveness of DHA-PPQ has been estimated as malaria recrudescence within 60 days.

Results

The rate of K13(C580Y) ranged from 75.8% in Krong Pa to 1.2% in Huong Hoa district. DPC3 prevalence was higher in Krong Pa than in Huong Hoa (86.2% vs 39.3%). In the two districts, the prevalence of confirmed resistance was found in 69.0% and 1.2% of patients, respectively. In Thuan Bac district, we found intermediate prevalence of confirmed resistance. Treatment failure was not evidenced in any district. PPQ resistance was not evidenced. Confirmed resistance was associated to the persistence of parasites on day 28 and to 3.4-fold higher parasite density at diagnosis. The effectiveness of malaria control strategies was very high in the studied districts.

Conclusion

No treatment failure has been observed in presence of high prevalence of ART resistance and in absence of PPQ resistance. K13(C580Y) was strongly associated to higher parasitemia at admission, on days 3 and 28. Slower parasite clearance was also observed in younger patients.

Correlation of Oxidative Stress Biomarkers and Hematological Parameters in Blood Cancer Patients from Sardinia, Italy

Background: Over the last few decades, there has been a dramatic increase in hematological malignancies (HMs) in the population of Sardinia. It is accepted that oxidative stress biomarkers have been demonstrated to be prognostically important in various neoplastic diseases. The aim of this study is to evaluate serum vitamin E, total antioxidant capacity (TAC), Malondialdehyde (MDA) and reactive oxygen species (ROS) levels in 80 Sardinian patients with different HMs [acute myeloid leukemia (AML)(n=20), myelodysplastic syndromes (MDS) (n=20), Hodgkin lymphoma (HL) (n=20) and non-Hodgkin lymphoma (NHL) (n=20)] on the day of their diagnosis. Materials and Methods: Samples from all participants were obtained after an overnight fast (at least 10 hours). This study was approved and conducted in accordance with Good Clinical Practice guidelines and the Declaration of Helsinki. Patients and controls provided written, informed consent before entering the study. All study participants' medical history and their medication were documented upon enrolling. Results: Lower levels of TAC and Vitamin E were observed in most of the studied groups compared to healthy controls (0.41-0.49 mmol/L vs. 0.56 mmol/L) (19.55-28.55 μmol/L vs. 34.51 μmol/L). Moreover, higher average MDA levels were observed in HL and NHL patients compared to healthy controls (16.6 ng/ml-17.8 ng/ml vs. 7.4 ng/ml). Additionally, the ROS values of all studied groups were found elevated. Serum TAC showed significant negative correlations with MDA values (R= -0.51; P<0.001). Statistical significance was observed in all hematological parameters, producing either positive or negative correlation with at least one OS biomarker. Conclusion: The present data suggest that Sardinian patients with HL and NHL on the day of their diagnosis presented the highest OS in comparison to AML and healthy subjects. Moreover, MDS patients presented high OS status. Likewise, our results also indicated that changes in their hematological indices are eminent of their oxidative and antioxidative status.

Induction of high tolerance to artemisinin by sub-lethal administration: A new in vitro model of P. falciparum

Artemisinin resistance is a major threat to malaria control efforts. Resistance is characterized by an increase in the Plasmodium falciparum parasite clearance half-life following treatment with artemisinin-based combination therapies (ACTs) and an increase in the percentage of surviving parasites. The remarkably short blood half-life of artemisinin derivatives may contribute to drug-resistance, possibly through factors including sub-lethal plasma concentrations and inadequate exposure. Here we selected for a new strain of artemisinin resistant parasites, termed the artemisinin resistant strain 1 (ARS1), by treating P. falciparum Palo Alto (PA) cultures with sub-lethal concentrations of dihydroartemisinin (DHA). The resistance phenotype was maintained for over 1 year through monthly maintenance treatments with low doses of 2.5 nM DHA. There was a moderate increase in the DHA IC50 in ARS1 when compared with parental strain PA after 72 h of drug exposure (from 0.68 nM to 2 nM DHA). In addition, ARS1 survived treatment physiologically relevant DHA concentrations (700 nM) observed in patients. Furthermore, we confirmed a lack of cross-resistance against a panel of antimalarials commonly used as partner drugs in ACTs. Finally, ARS1 did not contain Pfk13 propeller domain mutations associated with ART resistance in the Greater Mekong Region. With a stable growth rate, ARS1 represents a valuable tool for the development of new antimalarial compounds and studies to further elucidate the mechanisms of ART resistance.

Total antioxidant capacity in Mediterranean β-thalassemic patients

BACKGROUND

Beta thalassemia major (BT) is an inherited blood disorder caused by reduced or absent synthesis of the hemoglobin beta chains, associated with profound anemia, jaundice, splenomegaly, expanded bone marrow volume, siderosis and cardiomegaly. Because of repeated blood transfusions, BT patients are subjected to peroxidative tissue injury due to secondary iron overload.

OBJECTIVES

The aim of the study was to analyze: 1) the total antioxidant capacity (TAC) value in BT patients (study group) and their healthy controls (control group) from Greece (Central Macedonia) and Italy (Sardinia); correlations between 2) the TAC and ferritin levels of BT patients, and 3) the TAC and ferritin values in BT patients with different chelation therapies.

MATERIAL AND METHODS

The studied group consisted of 60 subjects diagnosed with BT (41 female, mean age: 41.5 ± 9.5 years) and 40 healthy controls matched with age and sex (31 female, mean age: 38.5 ± 3.7 years). Desferrioxamine (DFO) was the basic previous chelation regimen for all BT patients. Antioxidant activity was assayed spectrophotometrically, using a TAC Kit (Total Antioxidant Capacity Colorimetric assay kit, produced by Cayman Chemical Co.), and ferritin was assayed by immunoturbidimetry.

RESULTS

Lower levels of TAC were observed in BT patients of both countries when compared with controls (1.83 mmol/L vs 2.7 mmol/L in the Italian study group and controls and 2.42 mmol/L vs 3.2 mmol/L in the Greek study group and controls). There were no significant correlations between plasmatic TAC and ferritin. Furthermore, deferasirox was the only chelation treatment in which TAC showed a correlation in both regions.

CONCLUSIONS

Our results potentially suggest that the reduced levels of TAC detectable in BT patients could demonstrate their reduced antioxidant defensive mechanisms.