4-Hydroxynonenal – major bioactive marker of lipid peroxidation

While oxidative stress is generally considered mostly as pathogenic component of stress and age associated diseases, reactive aldehydes such as 4-hydroxy-2-nonenal (HNE) are considered mostly as the end-products of lipid peroxidation, which act as a “second toxic messenger of free radicals”. However, findings of growth regulating activities of HNE that overlapped with the development of the first monoclonal and polyclonal antibodies specific for the HNE-protein adducts led to the introduction of qualitative and quantitative determinations of the HNE presence in various (patho)physiological processes and to the change of consideration of the aldehyde’s bioactivities from toxicity into cell signaling, growth regulation and hormesis.Thus, the progress in the fields of the redox signaling and broad bioactivities or reactive oxygen and nitrogen species changed our overall approach to oxidative stress and to consideration of HNE not only as toxic but more general as a “second messenger of free radicals” and the growth regulating factor. Moreover, findings of the HNE-protein adducts in various organs under physiological circumstances support the concept of “oxidative homeostasis”, which implies that oxidative stress and lipid peroxidation are not only pathological but also physiological processes. Accordingly, HNE could play important role in oxidative homeostasis, while complementary research approaches might reveal the relevance of the aldehydic-protein adducts as major bioactive markers of oxidative stress, lipid peroxidation and oxidative homeostasis.Keywords 4-Hydroxynonenal, lipid peroxidation, oxidative stress, pathophysiology, reactive aldehydes aling, growth regulation and hormesis.  

Antioxidants and Second Messengers of Free Radicals

The history of science can teach modern men that our understanding of life is to a great extent based on the accuracy of the analytical methods that we use and, on our readiness to oppose dogmatic opinions, which are based on outdated methods and black/white approaches to the major questions raised by mankind in the past. The recent decades have brought a lot of new insights into the fundamentals of the active principles of reactive oxygen species that are necessary for living cells, but which also cause dangerous pathophysiological processes. Accordingly, although they were previously considered to be the most undesired toxic compounds generated as the final products of the oxidative degradation of lipids, reactive aldehydes are now considered to play important roles both in health and in major diseases. Represented mostly by 4-hydroxynonenal (HNE), a substance discovered only fifty years ago, reactive aldehydes are the focus of research not only because of their toxicity but also because of their positive effects regulating the most important metabolic processes such as growth of living cells or the death of cells. Better understanding the interactions between reactive aldehydes and natural or synthetic antioxidant substances might eventually help us to better monitor, prevent and control modern diseases, thus building pillars for the development of the modern, multidisciplinary life sciences and integrative medicine of the 21st century

Adjuvant Cancer Biotherapy by Viscum Album Extract Isorel: Overview of Evidence Based Medicine Findings

Within the integrative medicine one of the most frequently used adjuvant cancer biotherapies is based on aqueous mistletoe (Viscum album) extracts. Tumor growth inhibition, stimulation of host immune response and improvement of the quality of life are the positive effects of mistletoe therapy described in several preclinical and clinical studies. However, cumulative results of the evidence based medicine findings on such treatments are rarely given. Therefore, this paper evaluates the evidence based findings describing effects of the Viscum album extract Isorel in cancer therapy with respect to the type of therapy, stage and type of illness. This study presents cumulated data for 74 patients with different types and stages of cancer treated by Viscum album extract as adjuvant treatment to different conventional therapies, mostly combined surgery and radiotherapy. The biotherapy effectiveness was evaluated according to the outcome as 1) no major therapeutic improvement (15% of patients), 2) prevention of tumor recurrence (47% of patients) and 3) regression of cancer (38% of patients). Notably, there was no obvious health worsening during the follow up period at all. Thus, the results obtained for conventional anticancer therapies combined with adjuvant biotherapy based on Viscum album extract seem to be beneficial for the majority of cancer patients (85%) without serious side effects

Adjuvant Cancer Biotherapy by Viscum Album Extract Isorel: Overview of Evidence Based Medicine Findings

Within the integrative medicine one of the most frequently used adjuvant cancer biotherapies is based on aqueous mistletoe (Viscum album) extracts. Tumor growth inhibition, stimulation of host immune response and improvement of the quality of life are the positive effects of mistletoe therapy described in several preclinical and clinical studies. However, cumulative results of the evidence based medicine findings on such treatments are rarely given. Therefore, this paper evaluates the evidence based findings describing effects of the Viscum album extract Isorel in cancer therapy with respect to the type of therapy, stage and type of illness. This study presents cumulated data for 74 patients with different types and stages of cancer treated by Viscum album extract as adjuvant treatment to different conventional therapies, mostly combined surgery and radiotherapy. The biotherapy effectiveness was evaluated according to the outcome as 1) no major therapeutic improvement (15% of patients), 2) prevention of tumor recurrence (47% of patients) and 3) regression of cancer (38% of patients). Notably, there was no obvious health worsening during the follow up period at all. Thus, the results obtained for conventional anticancer therapies combined with adjuvant biotherapy based on Viscum album extract seem to be beneficial for the majority of cancer patients (85%) without serious side effects

1,4-Dihydropyridine Derivatives: Dihydronicotinamide Analogues—Model Compounds Targeting Oxidative Stress

Many 1,4-dihydropyridines (DHPs) possess redox properties. In this review DHPs are surveyed as protectors against oxidative stress (OS) and related disorders, considering the DHPs as specific group of potential antioxidants with bioprotective capacities. They have several peculiarities related to antioxidant activity (AOA). Several commercially available calcium antagonist, 1,4-DHP drugs, their metabolites, and calcium agonists were shown to express AOA. Synthesis, hydrogen donor properties, AOA, and methods and approaches used to reveal biological activities of various groups of 1,4-DHPs are presented. Examples of DHPs antioxidant activities and protective effects of DHPs against OS induced damage in low density lipoproteins (LDL), mitochondria, microsomes, isolated cells, and cell cultures are highlighted. Comparison of the AOA of different DHPs and other antioxidants is also given. According to the data presented, the DHPs might be considered as bellwether among synthetic compounds targeting OS and potential pharmacological model compounds targeting oxidative stress important for medicinal chemistry

Double-edged sword behaviour of gallic acid and its interaction with peroxidases in human microvascular endothelial cell culture (HMEC-1). Antioxidant and pro-oxidant effects*

A previous report from our group had shown in vitro a direct interaction between peroxidases and dietary antioxidants at physiological concentrations, where in the absence of H2O2, the antioxidants could serve as oxidizing substrates for the peroxidases. However, the physiological relevance of those findings had not been evaluated. The main objective of this study was to determine whether the oxidizing products produced in the interaction between peroxidase and gallic acid at a physiological concentration of 1 μM may promote cell death or survival in a human microvascular endothelial cell line (HMEC-1). Our findings suggested that gallic acid may show a double-edged sword behaviour, since in the absence of H2O2 it may have a pro-oxidant effect which may promote cell injury (evidenced by LDH, Crystal Violet and calcein AM viability/citotoxicity assays), while in the presence of H2O2, gallic acid may act as an antioxidant inhibiting oxidative species produced in the peroxidase cycle of peroxidases. These observations were confirmed with several oxidative stress biomarkers and the evaluation of the activation of cell survival pathways like AKT and MAPK/ERK.This study was supported by grants from the Spanish Ministry of Science and Innovation (CENIT METDEV- FUN) to M. Portero-Otín, the Spanish Instituto de Salud Carlos III (FIS PI081238) to J. Boada and (FIS PI081843) to M. Portero-Otin and by the COST action B35

Clinical relevance of biomarkers of oxidative stress

SIGNIFICANCE Oxidative stress is considered to be an important component of various diseases. A vast number of methods have been developed and used in virtually all diseases to measure the extent and nature of oxidative stress, ranging from oxidation of DNA to proteins, lipids, and free amino acids. Recent Advances: An increased understanding of the biology behind diseases and redox biology has led to more specific and sensitive tools to measure oxidative stress markers, which are very diverse and sometimes very low in abundance. CRITICAL ISSUES The literature is very heterogeneous. It is often difficult to draw general conclusions on the significance of oxidative stress biomarkers, as only in a limited proportion of diseases have a range of different biomarkers been used, and different biomarkers have been used to study different diseases. In addition, biomarkers are often measured using nonspecific methods, while specific methodologies are often too sophisticated or laborious for routine clinical use. FUTURE DIRECTIONS Several markers of oxidative stress still represent a viable biomarker opportunity for clinical use. However, positive findings with currently used biomarkers still need to be validated in larger sample sizes and compared with current clinical standards to establish them as clinical diagnostics. It is important to realize that oxidative stress is a nuanced phenomenon that is difficult to characterize, and one biomarker is not necessarily better than others. The vast diversity in oxidative stress between diseases and conditions has to be taken into account when selecting the most appropriate biomarker. Antioxid. Redox Signal. 00, 000-000

Dihydropyridine Derivatives as Cell Growth Modulators In Vitro

The effects of eleven 1,4-dihydropyridine derivatives (DHPs) used alone or together with prooxidant anticancer drug doxorubicin were examined on two cancer (HOS, HeLa) and two nonmalignant cell lines (HMEC, L929). Their effects on the cell growth (3H-thymidine incorporation) were compared with their antiradical activities (DPPH assay), using well-known DHP antioxidant diludine as a reference. Thus, tested DHPs belong to three groups: (1) antioxidant diludine; (2) derivatives with pyridinium moieties at position 4 of the 1,4-DHP ring; (3) DHPs containing cationic methylene onium (pyridinium, trialkylammonium) moieties at positions 2 and 6 of the 1,4-DHP ring. Diludine and DHPs of group 3 exerted antiradical activities, unlike compounds of group 2. However, novel DHPs had cell type and concentration dependent effects on 3H-thymidine incorporation, while diludine did not. Hence, IB-32 (group 2) suppressed the growth of HOS and HeLa, enhancing growth of L929 cells, while K-2-11 (group 3) enhanced growth of every cell line tested, even in the presence of doxorubicin. Therefore, growth regulating and antiradical activity principles of novel DHPs should be further studied to find if DHPs of group 2 could selectively suppress cancer growth and if those of group 3 promote wound healing