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Background: Due to their immunocompromised conditions, hemodialysis (HD) patients are at high risk of being infected with SARS-CoV-2 with poor clinical outcomes. We explored safety, efficacy and variability factors associated with vaccine immune response in these patients. Methods: From 18 January to 30 April 2021, 87 HD patients were enrolled in this study and subdivided in two sub-groups: SARS-CoV-2 positive prior to vaccination and naïve patients. The vaccination protocol included two intramuscular shots of the mRNA vaccine at a 28-day interval. The vaccine response was evaluated one month after the first and second shots by measuring anti-S antibody titers. Findings: 44% of the patients studied, were women; median age was 58 years. One month after the first shot, 64.3% of patients had anti-S antibody titers < 50 U/mL while 96.5% had anti-S antibody titers > 250 U/mL one month after the second shot. We show that the anti-SARS-CoV-2 spike mRNA vaccine elicits a great tolerability in HD patients. Importantlly, the vaccine response is characterized by a higher rate of seroconversion than conventional vaccination, as we have shown for the hepatitis B vaccine. We highlight two major factors of variability of the vaccine response. First, pre-exposure to SARS-CoV-2 boosts humoral response, as 95% of SARS-CoV-2 positive patients developed anti-S antibody titers > 250 U/L just after the first shot. Secondly, on the contrary fluid overload strikingly appears, limiting the vaccine response, as 84% of HD patients with fluid overload elicit lower anti-S antibody titers after the first shot. Interpretation: Our findings show that the immunogenic profile induced by mRNA vaccines in HD patients represents a promising a protective strategy that is associated with greater tolerability. Fluid overload may be considered as a novel factor that hinders the immune response in HD patients and further studies will be needed to investigate this working hypothesis.

Highlights • Mitochondria are the hub of cellular oxidative homeostasis. • Mitochondria are the major source of reactive oxygen species (ROS). • Extracellular mitochondria are found in blood, in circulating platelets and vesicles. • COVID-19 pathogenesis is aggravated by the hyper- inflammatory state. • Inflammation activates events leading to microbiota & mitochondrial oxidative damage. • Mitochondrial damage contributes to coagulopathy, ferroptosis & microbial dysbiosis. • Blood & platelet mitochondria dysfunction may accelerate systemic coagulopathy events. • Targeting mitochondria dysfunction may provide useful therapeutic strategies against COVID-19 pathogenesis., The COVID-19 pandemic caused by the coronavirus (SARS-CoV-2) has taken the world by surprise into a major crisis of overwhelming morbidity and mortality. This highly infectious disease is associated with respiratory failure unusual in other coronavirus infections. Mounting evidence link the accelerated progression of the disease in COVID-19 patients to the hyper-inflammatory state termed as the “cytokine storm” involving major systemic perturbations. These include iron dysregulation manifested as hyperferritinemia associated with disease severity. Iron dysregulation induces reactive oxygen species (ROS) production and promotes oxidative stress. The mitochondria are the hub of cellular oxidative homeostasis. In addition, the mitochondria may circulate “cell-free” in non-nucleated platelets, in extracellular vesicles and mitochondrial DNA is found in the extracellular space. The heightened inflammatory/oxidative state may lead to mitochondrial dysfunction leading to platelet damage and apoptosis. The interaction of dysfunctional platelets with coagulation cascades aggravates clotting events and thrombus formation. Furthermore, mitochondrial oxidative stress may contribute to microbiota dysbiosis, altering coagulation pathways and fueling the inflammatory/oxidative response leading to the vicious cycle of events. Here, we discuss various cellular and systemic incidents caused by SARS-CoV-2 that may critically impact intra and extracellular mitochondrial function, and contribute to the progression and severity of the disease. It is crucial to understand how these key modulators impact COVID-19 pathogenesis in the quest to identify novel therapeutic targets that may reduce fatal outcomes of the disease.

Polyphenols have attracted huge interest among researchers of various disciplines because of their numerous biological activities, such as antioxidative, antiinflammatory, antiapoptotic, cancer chemopreventive, anticarcinogenic, and antimicrobial properties, and their promising applications in many fields, mainly in the medical, cosmetics, dietary supplement and food industries. In this review, the latest scientific findings in the research on polyphenols interaction with the microbiome and mitochondria, their metabolism and health beneficial effects, their involvement in cognitive diseases and obesity development, as well as some innovations in their analysis, extraction methods, development of cosmetic formulations and functional food are summarized based on the papers presented at the 13th World Congress on Polyphenol Applications. Future implications of polyphenols in disease prevention and their strategic use as prophylactic measures are specifically addressed. Polyphenols may play a key role in our tomorrow´s food and nutrition to prevent many diseases.

Until recently restricted to hereditary mitochondrial diseases, mitochondrial dysfunction is now recognized as a key player and strategic factor in the pathophysiological of many human diseases, ranging from the metabolism, vascular, cardiac, and neurodegenerative diseases to cancer. Because of their participation in a myriad of cellular functions and signaling pathways, precisely identifying the cause of mitochondrial "dysfunctions" can be challenging and requires robust and controlled techniques. Initially limited to the analysis of the respiratory chain functioning, these analytical techniques now enlarge to the analyses of mitochondrial and cellular metabolism, based on metabolomic approaches.Here, we address the methods used to assay mitochondrial dysfunction, with a highlight on the techniques used in diagnosis on tissues and cells derived from patients, the information they provide, and their strength and weakness.Targeting mitochondrial dysfunction by various strategies is a huge challenge, requires robust methods of evaluation, and should be able to take into consideration the mitochondria dynamics and localization. The future of mitochondrial medicine is strongly related to a perfect comprehension of its dysfunction.

Until recently restricted to hereditary mitochondrial diseases, mitochondrial dysfunction is now recognized as a key player and strategic factor in the pathophysiological of many human diseases, ranging from the metabolism, vascular, cardiac, and neurodegenerative diseases to cancer. Because of their participation in a myriad of cellular functions and signaling pathways, precisely identifying the cause of mitochondrial "dysfunctions" can be challenging and requires robust and controlled techniques. Initially limited to the analysis of the respiratory chain functioning, these analytical techniques now enlarge to the analyses of mitochondrial and cellular metabolism, based on metabolomic approaches.Here, we address the methods used to assay mitochondrial dysfunction, with a highlight on the techniques used in diagnosis on tissues and cells derived from patients, the information they provide, and their strength and weakness.Targeting mitochondrial dysfunction by various strategies is a huge challenge, requires robust methods of evaluation, and should be able to take into consideration the mitochondria dynamics and localization. The future of mitochondrial medicine is strongly related to a perfect comprehension of its dysfunction.

Called “bioblasts” in 1890, named “mitochondria” in 1898, baptized in 1957 as the “powerhouse of the cell” and christened in 1999 as the “motor of cell death”, mitochondria have been anointed in 2017 as “powerhouses of immunity”. In 1962, for the first time a causal link between mitochondria and human diseases was described, the genetic basis for which was revealed in 1988. The term “mitochondrial medicine” was coined in 1994. Research into mitochondria has been conducted ever since light microscopic studies during the end of the 19th century revealed their existence. To this day, new discoveries around this organelle and above all new insights into their fundamental role for human health and disease continue to surprise. Nowadays hardly any disease is known for which either the etiology or pathogenesis is not associated with malfunctioning mitochondria. In this second part of our review about recent developments in mitochondrial medicine we continue tracking and highlighting selected lines of mitochondrial research from their beginnings up to the present time. Mainly written for readers not familiar with this cell organelle, we hope both parts of our review will substantiate what we articulated over a decade ago, namely that the future of medicine will come through better understanding of the mitochondrion.

Background/Aims: Hemodialysis-associated muscle cramp (HAMC) is a common complication under citrate dialysate (CD) occurring in 30% of cases. Our objectives were to assess the gut microbiota quality, mitochondrial activity, and to investigate their possible relationship with HAMC. Methods: Ten end-stage renal disease patients (78.9 ± 2.1 years) treated by hemodialysis (HD) with CD were enrolled and then classified according to the frequency of HAMCs: “frequent HAMCs group” (n = 5) and “absence of HAMCs group” (n = 5). Gut microbiota quality, mitochondrial activity, and some markers of oxidative stress (OS) were investigated. Results: In patients with cramps, gut microbiota diversity seemed lower and some genera including Helicobacter, Lachnospira, Roseburia, and Haemophilus seemed over-expressed, a significant increase of citratemia and significant lowering mitochondrial function were observed. No difference was observed on the OS markers. Conclusion: This first clinical study revealed a possible dysbiosis of microbiota and a mitochondrial dysfunction into HD patients with cramps under CD compared to patients without cramp.

Editorial

Research into elucidating structure and function of mitochondria has been quite steady between the time of discovery during the end of the 19th century until towards the late 1980’s. During the 1990s there was talk about a “comeback” of this organelle reflecting a widely revitalized interest into mitochondrial research which was based on two major discoveries made during that time. The first was the etiological association between human diseases and mitochondrial DNA mutations, while the second revealed the crucial function of mitochondria during apoptosis. The March 5th, 1999 issue of Science even featured a textbook image of a mitochondrion on its front cover and was entirely dedicated to this organelle. Whilst the term “comeback” might have been appropriate to describe the general excitement surrounding the new mitochondrial discoveries made during the 1990s, a term for describing the progress made in mitochondrial research during the last two decades is difficult to find. Between 2000 and 2020 the number of publications on mitochondria has skyrocketed. It is now widely accepted that there hardly exists any human disease for which either the etiology or pathogenesis does not seem to be associated with mitochondrial malfunction. In this review we will discuss and follow several lines of mitochondrial research from their early beginnings up to the present. We hope to be able to convince the reader of what we expressed about a decade ago, that the future of medicine will come through mitochondria.

For several decades, many antioxidants studies have emphasized the marked disparity between the beneficial effect of the antioxidants shown in preclinical studies and their inability to show beneficial effects in clinical trials. Besides, it is not uncommon to find highly contradictory clinical results, which may explain why consumers are less enthusiastic for antioxidant uses. This perspective article aims to highlights the critical role of Reactive Oxygen Species (ROS) and antioxidants, the potential mechanisms that might account for these discrepancies in clinical trials and some strategies to target oxidative stress and mitochondria by antioxidants. We need urgently to set up standard methods to evaluate antioxidants and oxidative stress in human and in particular at mitochondria level. The determination of what the basal level of ROS is in normal human may be used to identify pathologic ROS levels in patients and ultimately guide antioxidants treatment.

Superoxide dismutase (SOD) has now been known for 35 years. While the superoxide radical and SOD have been implicated in many disease states including inflammatory diseases, diseases of ischemia and reperfusion, neurodegenerative diseases, and cancer, as well as more subtle roles in cell signaling and perhaps in immune function, SOD is not yet in widespread usage in human clinical medicine. One obstacle has been that none of the three human SODs possesses attractive pharmacological properties to make it a clinically useful therapeutic agent. These problems may be overcome either by the design of SOD-mimetic drugs or by genetically re-engineering the human SOD genes to produce SODs with more desirable and controllable properties for human clinical usage. A second obstacle has been the fact that a delicate balance is involved between superoxide and SOD. Produced in proper amount, superoxide is a normal and useful metabolite, serving important roles as a signaling molecule in processes such as cell division, and even serving to act as a terminator of lipid peroxidation. When flagrantly overproduced, however, the radical can initiate lipid peroxidation, protein oxidation, and DNA damage, leading to cell dysfunction and death by apoptosis or necrosis. It is these paradoxical properties that complicate the precise restoration of optimal balance between superoxide and SOD when that balance has been upset by injury, disease, or aging.

Oxidative stress is now recognized as accountable for redox regulation involving reactive oxygen species (ROS) and reactive nitrogen species (RNS). Its role is pivotal for the modulation of critical cellular functions, notably for neurons astrocytes and microglia, such as apoptosis program activation, and ion transport, calcium mobilization, involved in excitotoxicity. Excitotoxicity and apoptosis are the two main causes of neuronal death. The role of mitochondria in apoptosis is crucial. Multiple apoptotic pathways emanate from the mitochondria. The respiratory chain of mitochondria that by oxidative phosphorylation, is the fount of cellular energy, i.e. ATP synthesis, is responsible for most of ROS and notably the first produced, superoxide anion (O(2)(;-)). Mitochondrial dysfunction, i.e. cell energy impairment, apoptosis and overproduction of ROS, is a final common pathogenic mechanism in aging and in neurodegenerative disease such as Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). Nitric oxide (NO(;)), an RNS, which can be produced by three isoforms of NO-synthase in brain, plays a prominent role. The research on the genetics of inherited forms notably ALS, AD, PD, has improved our understanding of the pathobiology of the sporadic forms of neurodegenerative diseases or of aging of the brain. ROS and RNS, i.e. oxidative stress, are not the origin of neuronal death. The cascade of events that leads to neurons, death is complex. In addition to mitochondrial dysfunction (apoptosis), excitotoxicity, oxidative stress (inflammation), the mechanisms from gene to disease involve also protein misfolding leading to aggregates and proteasome dysfunction on ubiquinited material.

Objective . – To determine if asymptomatic stable chronic hyperlactatemia in human immunodeficiency virus (HIV)-infected patients under highly active antiretroviral therapy (HAART, including nucleoside analog reverse transcriptase inhibitors (NRTI)) could be improved by antioxidant supplementation. Design . – To match two groups of patients taking NRTI for at least 24 months: 15 without and 15 with antioxidant supplementation (vitamin E, β-carotene, N -acetylcysteine, selenium, Gingko biloba extracts and nutritional supplements). For both the groups, the supplementation by antioxidants or its lack was carefully assessed. Venous lactatemia, blood oxidative stress markers (plasma lipid peroxidation, enzymatic and non-enzymatic antioxidants), CDC revisited classification, CD4 count and viral load, NRTI (with or without stavudine) and other antiretroviral drugs used, lipoatrophy, central fat accumulation were assessed. Results . – Patients were not statistically different with respect to the CDC classification, CD4 count, viral load and characteristics of antiretroviral therapy. Blood oxidative stress markers, i.e. vitamin E, vitamin A and β-carotene tended to be higher in the supplemented group. The difference observed in venous lactate concentration between the two groups was significant (1.37 ± 0.10 vs. 1.82 ± 0.19 mmol/l in the supplemented and non-supplemented groups, respectively P = 0.04). Conclusion . – Antioxidant supplementation improves the asymptomatic stable chronic hyperlactatemia observed in HIV-infected patients taking HAART including NRTI for a long time. Controlled studies are needed to demonstrate the efficacy of this supplementation on mitochondrial toxicity observed during HAART and the possible usefulness of its combination with mitochondrial cofactors like carnitine, riboflavine, coenzyme Q, α-lipoic acid.

Inhibition of copper-induced low-density lipoprotein (LDL) oxidation by phenolic acids and their ethyl esters was investigated. LDL oxidation was evaluated by the hydroperoxide concentration and the chromatographic pattern of apoprotein fractions after fast protein liquid chromatography (FPLC). Antiradical properties against 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical and 2,2’-azobis(2-amidinopropane)dihydrochloride (AAPH) were also investigated, and lipophilicity determined by thin-layer chromatography. Caffeic acid at 5 μM and sinapic acid at 10 μM protected LDL against oxidation, inhibiting both hydroperoxide formation and the increase of apoprotein negative charge. Ferulic, gallic and p-hydroxy cinnamic acids were ineffective. Ethyl esterification increased the lipophilicity of the five acids, and enhanced the antioxidant properties of caffeic, sinapic and ferulic acids. Ethyl caffeate was protective at 1 μM. In contrast, gallic and p-hydroxy cinnamic ethyl esters were ineffective. Our results indicate that ethyl esterification of phenolic acids increases lipophilicity of their ethyl esters and may enable a better incorporation into the lipid layer of the LDL particle and the exertion of their antioxidant effect in the true site of lipoperoxidation. However, increasing lipophilicity is not the only mechanism able to potentiate preexisting antioxidant properties of molecules, and probably other mechanisms are implicated.

The frequent neoplastic disorders present in HIV-infected patients and the implication of oxidative stress in AIDS-Kaposi's sarcoma pathogenesis prompted us to study whether the mechanisms implicated in genotoxic effects of clastogenic factors (CFs) (i.e., chromosome damaging materials released by cells under conditions of oxidant stress) can play a role in HIV-1 expression and whether exogenous superoxide dismutase can inhibit the clastogenic and HIV-inducing effects of CFs. CFs were found in the plasma of all HIV-1 infected patients (n = 21) of this study group, in asymptomatic (CDC II) as well as in symptomatic patients (CDC IV). In addition to their chromosome damaging effect, CFs are able to upregulate HIV-1 expression in U1 cells and in PBMCs activated with PHA and IL2 at all time points (p < .05). Their formation, therefore, is an early event in the disease. It occured despite antiviral medication in these patients. Superoxide dismutase inhibited the clastogenic and the viral inducing effects (p < .05). On the basis of our findings, association of SOD mimetics or superoxide scavengers with antiviral drugs may be a new therapeutic approach. This polytherapy, if started early enough after infection, may prolong the latency period and limit the emergence of drug-resistant viral strains.

Mitochondrial dysfunction has been associated with the aging process and a large variety of human disorders, such as cardiovascular and neurodegenerative diseases, cancer, migraine, infertility, kidney and liver diseases, toxicity of drugs and many more. It is well recognized that the physiological role of mitochondria widely exceeds that of solely being the biochemical power plant of our cells. Over the recent years, mitochondria have become an interesting target for drug therapy, and the research field aimed at "targeting mitochondria" is active and expanding as witnessed by this already third edition of the world congress on targeting mitochondria. It is becoming a necessity and an urge to know why and how to target mitochondria with bioactive molecules and drugs in order to treat and prevent mitochondria-based pathologies and chronic diseases. This special issue covers a variety of new strategies and innovations as well as clinical applications in mitochondrial medicine.

The lay press often heralds polyphenols as panacea for all sorts of diseases. The rationale is that their antioxidant activity would prevent free radical damage to macromolecules. However, basic and clinical science is showing that the reality is much more complex than this and that several issues, notably content in foodstuff, bioavailability, or in vivo antioxidant activity are yet to be resolved. We summarize the recent findings concerning the effects of polyphenols on human health, analyze the current limitations at pitfalls, and propose future directions for research.

Since several decades anti-oxidants have been much studied, and scientists have tried to prove the preventive and curative effects in many chronic diseases. However, it is not uncommon to find highly contradictory clinical results, which may explain that consumers are less enthusiastic for anti-oxidants food supplements. First of all, definitions should be reviewed, such as that of free radicals (FR); all of them are not toxic. Some of them, such as nitric oxide, are necessary for the proper physiological functioning of the body, and eliminating them would be a mistake! However, other reactive oxygen species (ROS), which are not FR, are toxic, such as hydrogen peroxide. We have also redefined the oxidative stress, which it is not only the result of an imbalance between oxidants and anti-oxidants, but also the consequence of imbalance in the cellular redox status. The mechanisms of action, bioavailability, synergy and methods to determine the level of anti-oxidants are very sensitive topics, and it is crucial to study them if we want to obtain reliable clinical studies. Given the failure of clinical studies about anti-oxidant, we try to explain strategies which should be followed. First of all, the nature of the anti-oxidant is important; and an anti-oxidant from a natural origin must be preferred. Then, we proposed that the dose-effect was certainly responsible for the failure of tests. Indeed, doses administered in the studies was either too weak to obtain significant results, or too high, becoming pro-oxidative and eliminating the basal concentration of ROS (physiological role). Involvement of mitochondria and glycation are particularly discussed. Nutrigenomics and nutrigenetics are also discussed, which study the interactions between genetics and nutrition. Genetic polymorphism can explain the variable absorption of micronutrients. This concept leads to a truth believed by all scientists, namely the need to provide the right anti-oxidant, in adequate quantity, at the right place, at the right time and for a particular individual. To increase the anti-oxidant capacity of the body, the exogenous intake of anti-oxidants must be increased or the endogenous synthesis of anti-oxidants (SOD, GPX, GSH) must be stimulated. Targeting mitochondria and increasing their overall anti-oxidant defence system will be a challenge. Increasing the bioavailability of anti-oxidants and studying their passage through the blood-brain barrier must be also taken in consideration.

New discoveries in metagenomics and clinical research have highlighted the importance of the gut microbiota for human health through the regulation of the host immune response and energetic metabolism. The microbiota interacts with host cells in particular by intermingling with the mitochondrial activities. This mitochondria-microbiota cross-talk is intriguing because mitochondria share many common structural and functional features with the prokaryotic world. Several studies reported a correlation between microbiota quality and diversity and mitochondrial function. The mitochondrial production of reactive oxygen species (ROS) plays an important role during the innate immune response and inflammation, and is often targeted by pathogenic bacteria. Data suggest that excessive mitochondrial ROS production may affect ROS signaling induced by the microbiota to regulate the gut epithelial barrier. Finally, the microbiota releases metabolites that can directly interfere with the mitochondrial respiratory chain and ATP production. Short chain fatty acids have beneficial effects on mitochondrial activity. All these data suggest that the microbiota targets mitochondria to regulate its interaction with the host. Imbalance of this targeting may result in a pathogenic state as observed in numerous studies. The challenge to find new treatments will be to find strategies to modulate the quality and diversity of the microbiota rather than acting on microbiota metabolites and microbiota-related factors.

Mitochondrial dysfunction has been associated with the aging process and a large variety of human disorders, such as cardiovascular and neurodegenerative diseases, cancer, migraine, infertility, kidney and liver diseases, toxicity of drugs and many more. It is well recognized that the physiological role of mitochondria widely exceeds that of solely being the biochemical power plant of our cells. Over the recent years, mitochondria have become an interesting target for drug therapy, and the research field aimed at "targeting mitochondria" is active and expanding as witnessed by this already third edition of the world congress on targeting mitochondria. It is becoming a necessity and an urge to know why and how to target mitochondria with bioactive molecules and drugs in order to treat and prevent mitochondria-based pathologies and chronic diseases. This special issue covers a variety of new strategies and innovations as well as clinical applications in mitochondrial medicine.

We studied the cytotoxic effect of copper-oxidized LDL in human primary human umbilical vein endothelial cells (HUVEC) and the immortalized EA.hy 926 cell line. Copper oxidized LDL (50–200 μg apoB/ml) induced concentration-dependent apoptotic cell death in HUVEC but did not induce apoptosis in EA.hy 926 cells. Only necrotic EA.hy 926 cells were evidenced at all copper oxidized LDL concentrations (25–200 μg apoB/ml), oxidation states (lightly, moderately and extensively copper-oxidized LDL) and incubation periods (4, 8 and 20 h). The different mechanisms of cell death induced by copper-oxidized LDL in EA.hy 926 cells and HUVEC may be related to various factors such as cytokines. In this study, we investigated whether interleukin-8 may be implicated in this process. The interleukin-8 production was increased in EA.hy 926 cells but not in HUVEC incubated with oxidized LDL. This increase in EA.hy 926 cells was associated with necrosis but not apoptosis. Nevertheless, the addition of interleukin-8 to HUVEC did not inhibit apoptosis induced by oxidized LDL. As the lower antioxidant capacity of EA.hy 926 cells results in higher sensitivity to oxidized LDL cytotoxicity (as we previously described), the redox status of cells may also control the form of endothelial cell death. In atherosclerotic lesions, the formation of apoptotic endothelial cells may result in part from the induction by oxidized LDL.

We compared the susceptibility to oxidized LDL cytotoxicity of primary human umbilical vein endothelial cells (HUVEC) and EA.hy 926 cells. EA.hy 926 endothelial cells were more susceptible than HUVEC. To determine the basis of this difference, we evaluated the enzymatic antioxidant machinery in the two cell types. The antioxidant enzyme activities of superoxide dismutase, catalase and glutathione peroxidase were significantly lower in EA.hy cells than in HUVEC: 54%, 71% and 8% of the HUVEC enzyme activities respectively. Pre-incubation of the EA.hy 926 endothelial cells with glutathione peroxidase (100 IU/ml) inhibited the cytotoxic effect of oxidized LDL. Superoxide dismutase (300 or 600 IU/ml) and catalase (300 or 600 IU/ml) had no effect. Compared to HUVEC, the higher susceptibility of EA.hy 926 cells to oxidized LDL–induced injury may be associated with lower antioxidant defences, in particular with lower glutathione peroxidase activity which is known to eliminate lipid hydroperoxides and thereby to prevent the formation of damaging peroxyl radical intermediates.

The alveolar surface of the lung is a major target for oxidant injury. After injury, repair of the alveolar epithelium is dependent on the ability of epithelial type 2 (T2) cells to proliferate. The regulation of T2 cell proliferation and the effect of reactive oxygen (O2) species on this lung cell proliferation have not been well defined. To investigate this process we focused on the regulation of two late cell cycle genes, histone and thymidine kinase, in T2 cells and fibroblasts exposed in vitro to varying periods of hyperoxia (95% O2). Hyperoxia for 24 to 48 h arrested cell proliferation in a SV40T-immortalized T2 cell line we have developed and in primary and SV40T-immortalized lung fibroblasts. Despite the cessation of proliferation, histone and TK mRNA continued to be expressed at high levels; mRNA half-lives were markedly prolonged but neither protein was translated. Thus proliferation arrest induced by hyperoxia was associated with posttranscriptional control of at least two late cell cycle-related genes. This form of proliferation arrest is also seen when primary and SV40T-T2 cells but not fibroblasts are serum deprived, suggesting that T2 cells in vitro may be uniquely sensitive to alterations in their redox state and that these alterations in turn affect translational control of a subset of proliferation-related genes.

Previously, we demonstrated that ferulate ethyl and tocopherol reduced HIV replication. In this study, we investigate whether the conjugation of both compounds (O-tocopheryl succinyl O-ethyl ferulate) can increase HIV inhibition. We show here for the first time that O-tocopheryl succinyl O-ethyl ferulate inhibits 80% of HIV replication (HIV-1 acute infection and HIV transmission), inhibits cell lipoperoxidation and prevents cellular glutathione consumption. Compared to ferulate ethyl and tocopheryl succinyl, O-tocopheryl succinyl O-ethyl ferulate inhibits more HIV replication. This may be due in part to the great increase in the lipophilicity of this compound.

Brief introduction: The aim of this study was to evaluate the influence of freeze drying of sour cherry puree with sugars on phenolics and antioxidant activity (AOA) of the samples. Material and methods: Sour cherry purees were mixed with sugars (sucrose, trehalose or maltose) in the amount of 5, 10 or 20% and freeze-dried. Determination of phenolics, flavonoids, anthocyanins, percentage of polymeric colour and AOA was conducted and compared to results of freeze-dried puree. Results: The highest phenolic and anthocyanin content was determined in freeze-dried puree, 2.99 g/L and 408.70 mg/L, respectively. Freeze-dried samples with sugars had lower phenolic and anthocyanin contents. The highest phenolic content had samples prepared with 5% trehalose and 20% maltose, ~2.7 g/L, and the lowest with 20% of trehalose, ~1.9 g/L. The same samples had the highest anthocyanin content. Results of AOA highly depended on applied assay. Results of DPPH assay showed that all samples with sugars had higher AOA than freeze-dried puree, while in ABTS and FRAP assay all samples except sample with 20% of maltose had lower values of AOA. Conclusions: From obtained results it can be seen that sugar type and its amount had influence on the phenolics, anthocyanins and AOA.

Evidence accumulated in the last decade has demonstrated that a large proportion of the mitochondrial respiratory chain complexes in a variety of organisms is arranged in supramolecular assemblies called supercomplexes (SC) or respirasomes [1]. ln contrast to the random diffusion model, it is believed that Coenzyme a (CoQ) bound to supercomplexes participates in electron transfer by direct substrate channelling from Complex I to Complex III, providing kinetic advantage for electron transport. ln this perspective, we investigated CoQ behaviour in proteoliposomes from a mitochondrial fraction (R4B) enriched in Complexes I and III in the presence of different amounts of phospholipids and CoQ. lt was found that at high lipid/protein ratios the proteoliposomes exhibited NADH-cytochrome c reductase activity superimposable with that calculated from the pool equation describing randon collisions between Complexes I and III [2], whereas at low lipid/protein ratios the activity was higher than expected from pool behaviour. Concomitantly, it was found by blue-native electrophoresis that in the former case Complexes I and III were individual enzyme units embedded in the lipid membrane, whereas in the latter they were associated in the form of supercomplex I1III2. However, when the supercomplex I1III2 was dissociated by detergent (dodecyl maltoside) the overall NADH-cytochrome c activity was decreased, suggesting the occurrence of pool behaviour. These results provide a demonstration that supercomplex I1III2 confers faster and more efficient electron transfer by direct channelling in the CoQ region (Maranzana E., 2013). We then investigated the kinetics of NADH-cytochrome c reductase as a function of CoQ concentration in proteoliposomes at 1:1 lipid:protein ratio (e.9. presence of supercomplexes) and 30:1 lipid:protein ratio (e.g. absence of supercomplexes). Our preliminary results suggest that both samples exhibit Michaelis-Menten kinetics, in apparent contrast with the presence of substrate channelling by supercomplex I1III2 in the 1:1 sample. However, it is reasoned that CoQ bound in the supercomplex I1III2 is in dissociation equilibrium with the CoQ pool [1]. The finding that the apparent Km for CoQ is lower in the 1:1 sample agrees with this interpretation.