Skin damage by tropospheric ozone

Tropospheric (ground level) ozone (O3) is a secondary pollutant, emerging from other pollutants in the sunshine. Exposure to O3 correlates with higher pulmonary and cardiovascular mortality and affects reproductive health and the central nervous system acutely and chronically. Skin might be a potentially overlooked target organ of ambient O3. The experimental evidence suggests a positive correlation of O3 exposure with oxidative damage, impaired antioxidant defence and proinflammatory response in the skin. In time series studies it was observed that acute rises in O3 levels correlated with seeking medical help for skin conditions; however, whether these findings are specific to O3, is not yet clear. There is preliminary epidemiological evidence that long-term exposure to O3 is associated with premature skin aging. This finding was independent of co-exposure to other environmental factors affecting skin (e.g. ultraviolet radiation and air pollution). As concentrations of O3 are rising in many regions of the world, adverse cutaneous effects of O3 present a relevant public health concern.

Ozonation of Blood during Extracorporeal Circulation. I. Rationale, Methodology and Preliminary Studies

We investigated whether exposure of blood ex-vivo to oxygen-ozone (O2-O3) through a gas exchanger is feasible and practical. We first evaluated the classical dialysis-type technique but we soon realized that semipermeable membranes are unsuitable because they are hydrophilic and vulnerable to O3. We therefore adopted a system with hydrophobic O3-resistant hollow fibers enclosed in a polycarbonate housing with a membrane area of about 0.5 m2. First we tested the system with normal saline, determining the production of hydrogen peroxide (H2O2) at O3 concentrations from 5 to 40 μg/ml. We then evaluated critical parameters by circulating swine blood in vitro; this revealed that heparin is not an ideal anticoagulant for this system. Finally, we performed several experiments in sheep and defined optimal anticoagulant dose (sodium citrate, ACD), priming solution, volume of blood flow per min, volume and concentration of O2-O3 mixture flowing counter-current with respect to blood and the time necessary for perfusion in vivo. The biochemical parameters showed that an O3 concentration as low as 10 μg/ml is effective; this means that gas exchange and O3 reactivity are rapid and capable of inducing biological effects. The sheep showed no adverse effects even after 50 min of extracorporeal circulation at higher O3 concentrations (20 to 40 μg/ml) but the exchanger became less effective (low pO2 values) due to progressive clogging with cells.

Non-conventional rottlerin anticancer properties

In the past few years, we focused the interest on rottlerin, an old/new natural substance that, over the time, has revealed a number of cellular and molecular targets, all potentially implicated in the fight against cancer. Past and recent literature well demonstrated that rottlerin is an inhibitor of enzymes, transcription factors and signaling molecules that control cancer cell life and death. Although the rottlerin anticancer activity has been mainly ascribed to apoptosis and/or autophagy induction, recent findings unveiled the existence of additional mechanisms of toxicity. The major novelties highlighted in this mini review are the ability to bind and inhibit key molecules, such as ERK and mTOR, directly, thus independently of upstream signaling cascades, and to cause a profound dysregulation of cap-dependent protein translation through the mTORC1/4EBP1/eIF4E axis and by inhibition of eIF2, an initiation factor of translation that is negatively regulated by endoplasmic reticulum (ER) stress. These last mechanisms, proved to be lethal in cancer cell lines derived from breast and skin, strongly enforce the potential of rottlerin as a promising natural lead compound for the development of novel therapeutic approaches.

Keratinocytes oxidative damage mechanisms related to airbone particle matter exposure

Epidemiological evidences have correlated airbone particulate matter (PM) to adverse health effects, mainly linking to pulmonary and cardiovascular disease. Nevertheless, only recently, some studies reported detrimental effects of PM on other organs such as skin. In a recent work, we have reported increased oxidative and inflammatory responses in Reconstituted Human Epidermis (RHE) exposed to ambient particles (CAPs) and we also demonstrated the ability of CAPs to penetrate the skin tissue. The present study was aimed to better understand the cellular mechanisms beyond the oxidative changes induced by CAPs (5-10-25μg/mL) in human immortalized keratinocytes (HaCaT). After 24h of treatment, CAPs were able to enter the cells leading to a decrease in viability, increased levels of 4-hydroxinonenal products (4-HNE) and IL-1α release. Overall these data, suggest lipid and protein oxidative damage, as well as an increase of inflammatory response after being challenged with CAPs. In addition, 3h after CAPs exposure we found a significant increase in NF-kB and Nrf2 translocation into the nucleus. In contrast, no differences in gene expression and enzymatic activity of Nrf2 target genes were detected. This last finding could be explained by the ability of CAPs to possibly alter the binding of Nrf2 to the ARE DNA sequence.

Association between Siesta (Daytime Sleep), Dietary Patterns and the Presence of Metabolic Syndrome in Elderly Living in Mediterranean Area (Medis Study): The Moderating Effect of Gender

OBJECTIVES

Several lifestyle parameters including diet, physical activity and sleep were associated in isolation with the presence of Metabolic Syndrome (MetS) in adults, to date there is a paucity of studies which evaluated their combined role aging populations and especially with respect to gender. Therefore, the aim of the present study was to provide a global consideration of the lifestyle factors associated with MetS among elderly individuals.

DESIGN

Cross-sectional observational study.

SETTING

21 Mediterranean islands and the rural Mani region (Peloponnesus) of Greece.

PARTICIPANTS

during 2005-2015, 2749 older (aged 65-100 years) from were voluntarily enrolled in the study.

MEASUREMENTS

Dietary habits, energy intake, physical activity status, socio-demographic characteristics, lifestyle parameters (sleeping and smoking habits) and clinical profile aspects were derived through standard procedures. The presence of MetS was defined using the definition provided by NCEP ATP III (revised) and cluster analysis was used to identify overall dietary habit patterns.

RESULTS

The overall prevalence of MetS in the study sample was 36.2%, but occurred more frequently in females (40.0% vs. 31.8%, respectively, p=0.03). Individuals with MetS were more likely to sleep during the day (89.4% vs. 76.8% respectively, p=0.039) and frequent 'siesta' was positively linked to the odds of MetS presence in females (Odds Ratio (OR) =3.43, 95% Confidence Intervals (CI): 1.08-10.9), but not for men (p=0.999). The lower carbohydrate (i.e., 45.2% of total daily energy, 120±16gr/day) dietary cluster was inversely associated with the odds for MetS presence, but only for men (OR=0.094, 95%CI: 0.010-0.883).

CONCLUSIONS

Lifestyle parameters including sleep and diet quality are strongly associated with the presence of MetS in elderly cohort, but different their level of influence appears to be different, depending on gender. Further research is needed to better consider the role of lifestyle characteristics in the management of MetS in clinical practice.

Ozone: A Multifaceted Molecule with Unexpected Therapeutic Activity

A comprehensive outline for understanding and recommending the therapeutic use of ozone in combination with established therapy in diseases characterized by a chronic oxidative stress is currently available. The view of the absolute ozone toxicity is incorrect, because it has been based either on lung or on studies performed in artificial environments that do not correspond to the real antioxidant capacity of body compartments. In fact, ozone exerts either a potent toxic activity or it can stimulate biological responses of vital importance, analogously to gases with prospective therapeutic value such as NO, CO, H2S, H2, as well as O2 itself. Such a crucial difference has increasingly become evident during the last decade. The purpose of this review is to explain the aspects still poorly understood, highlighting the divergent activity of ozone on the various biological districts. It will be clarified that such a dual effect does not depend only upon the final gas concentration, but also on the particular biological system where ozone acts. The real significance of ozone as adjuvant therapeutic treatment concerns severe chronic pathologies among which are cardiovascular diseases, chronic obstructive pulmonary diseases, multiple sclerosis, and the dry form of age-related macular degeneration. It is time for a full insertion of ozone therapy within pharmaceutical sciences, responding to all the requirements of quality, efficacy and safety, rather than as either an alternative or an esoteric approach.

Inhibitions of mTORC1 and 4EBP-1 are key events orchestrated by Rottlerin in SK-Mel-28 cell killing

Earlier studies demonstrated that Rottlerin exerts a time- and dose-dependent antiproliferative effect on SK-Mel-28 melanoma cells during 24 h of treatment, but cytotoxicity due to cell death began only after a 48 h exposure. In the current study, in order to identify the type of cell death in this cell line, which is notoriously refractory to most anticancer therapies, and to clarify the underlying mechanisms of this delayed outcome, we searched for apoptotic, necrotic/necroptotic and autophagic traits in Rottlerin-exposed cells. Although SK-Mel-28 cells are both apoptosis and autophagy competent, Western blotting analysis, caspase activity assay, nuclear imaging and the effects of autophagy, apoptosis and necroptosis inhibitors, indicated that Rottlerin cytotoxicity was due to none of the aforementioned death mechanisms. Nevertheless, in growth arrested cells, the death did occur after a prolonged treatment and most likely ensued from the observed blockage of protein synthesis that reached levels expected to be incompatible with cell survival. From a mechanistic point of view, we ascribed this effect to the documented inhibition of mTORC1 activity; mTORC1 inhibition on the one hand led to a not deadly, rather protective autophagic response but, on the other hand caused a near complete arrest of protein synthesis. Interestingly, no cytotoxicity was found towards normal skin fibroblasts, which only resulted mildly growth arrested by the drug.

Phosphorylation-independent mTORC1 inhibition by the autophagy inducer Rottlerin

We recently found that Rottlerin not only inhibits proliferation but also causes Bcl-2- and Beclin 1-independent autophagic death in apoptosis-resistant breast adenocarcinoma MCF-7 cells. Having excluded a role for canonical signaling pathways, the current study was aimed to investigate the contribution of the AMPK/mTOR axis in autophagy induction and to search for the upstream signaling molecules potentially targeted by Rottlerin. Using several enzyme inhibitors, Western blotting analysis, mTOR siRNA and pull down assay, we demonstrate that the Rottlerin-triggered autophagy is mediated by inhibition of mTORC1 activity through a novel AMPK and mTORC1 phosphorylation-independent mechanism, likely mediated by the direct interaction between Rottlerin and mTOR.

Comparative effects between electronic and cigarette smoke in human keratinocytes and epithelial lung cells

Information about the harmful effects of vaping is sparse and inconsistent, therefore, since the use of electronic cigarettes (e-CIGs) has become increasingly popular as a tool to limit tobacco smoking, it is urgent to establish the toxicity of the commercial e-CIGs. Skin (HaCaT) and lung (A549) cells, the main targets of cigarette smoke (CS), were exposed to e-CIG vapor and CS using an in vitro system. The cytotoxic effect of the exposure was analyzed in both cell types by ultrastructural morphology, Trypan Blue exclusion test and LDH assay. In addition, pro-inflammatory cytokines were measured by the Bio-Plex assay. The cytotoxic components of e-CIG were restrained to the flavoring compound and, to a lesser extent, to nicotine although their effects were less harmful to that of CS. Humectants alone exhibited no cytotoxicity but induced the release of cytokines and pro-inflammatory mediators. Based on our results, we can state that exposure to e-CIG vapors results in far less toxic than exposure to CS. In fact, besides the deleterious effect of flavor and nicotine, even the humectants alone are able to evocate cytokines release. This study will hopefully promote the development of safer e-CIGs to help people quit smoking.

Resveratrol protects SR-B1 levels in keratinocytes exposed to cigarette smoke

Cigarette smoking (CS) has been strongly linked to several health conditions including heart disease, lung cancer, and other respiratory and circulatory ailments. Deleterious effects of cigarette smoking on skin have also been well documented, but unlike effects on other organs, damage does not depend upon inhalation. The upper layer of the skin, the stratum corneum (rich in cholesterol fatty acids and ceramide), is very susceptible to damage induced by exposure to environmental stressors that can modify its lipid composition and thereby affect its function of protecting skin from dehydration. Scavenger receptor B1 (SR-B1) is involved in the uptake of cholesterol in several tissues including skin. We previously demonstrated that CS exposure induces formation of aldehyde (HNE) adducts that decrease SR-B1 expression. As topical resveratrol, a well-known polyphenolic stilbene, has been demonstrated to show benefits against skin disorders, we investigated its possible role as a protective agent against CS-induced reduction of SR-B1 expression in cutaneous tissue. In this study, we demonstrate that resveratrol at doses ranging from 0.5 to 10 μM is not toxic and is able to increase SR-B1 protein levels in a dose-dependent manner in human keratinocytes. Moreover, when the cells that were pretreated with various doses of resveratrol were exposed to CS, the loss of SR-B1 was prevented in a dose-dependent manner. In addition, in keratinocytes, resveratrol was also able to prevent an increase in HNE-protein adducts induced by CS. In particular resveratrol was able to prevent HNE-SR-B1 adduct formation. Thus, resveratrol seems to be a natural compound that could provide skin with a defense against exogenous stressors by protecting the essential cholesterol receptor, SR-B1.

Free radicals and antioxidants: how to reestablish redox homeostasis in chronic diseases?

This review examines the biological role of oxidants and antioxidants continuously produced by all living cells. Physiologically, human beings, who have inherited good genes, used to eat moderately a healthy diet and exercised daily, both systems are equally important and essential in maintaining a normal long life. However, the aging process slowly leads to a disequilibrium that is accentuated in pathologies such as diabetes, cardiovascular, degenerative, pulmonary, infective diseases, and cancer. All of these diseases shorten the life span in about 80% of individuals and represent a huge social-economic problem for health authorities. Several factors such as excessive feeding, smoking, alcoholism, and a poor life-style conjure up to their realization. Their progress, initially promoted by some pathogens and a wrong life-style, is deeply accentuated by an excessive and deranged production of deadly oxidants no longer tameable by an inhibited control of the antioxidant defences. Effective orthodox drugs are able to slow down these ailments but they impoverish the quality of life because they cannot reactivate the innate ability to restore the complexity of the antioxidant system. Several potential approaches to renew this system have been discussed and their possible roles to reactivate a valid protection in at least some of the outlined pathologies. It is hoped to evaluate this integrated medical approach because it represents a sheet anchor for many patients.

[Oxidative stress and Rett syndrome]

The oxidative stress (OS) hypothesis is able to explain several features of Rett syndrome (RTT), a pervasive development disorder almost exclusively affecting females mainly caused by a mutation in the X-linked methyl-CpG binding protein 2 (MeCP2) gene. In particular, the generation of an OS imbalance is related to MeCP2 gene mutation type, as well as natural history, clinical heterogeneity of the disease, and is compatible with the potential reversibility of the disease observed in the RTT animal models. In addition, our findings indicate the importance of blood as a suitable biological fluid for detecting markers of central nervous system oxidative damage in RTT and underline the key role of interaction between organic chemists, OS biochemists, and clinicians in revealing potential new markers of the disease and identifying potential new targets and interventional strategies aimed at improving the quality of life of these patients, affected by a so far incurable disease. Further efforts in the near future are needed in order to dissect the "black box" of the molecular events likely linking the MeCP2 gene mutation to OS derangement and subsequent disease expression.

Hypoxia induces cell damage via oxidative stress in retinal epithelial cells

Retinal diseases (RD), including diabetic retinopathy, are among the most important eye diseases in industrialized countries. RD is characterized by abnormal angiogenesis associated with an increase in cell proliferation and apoptosis. Hypoxia could be one of the triggers of the pathogenic mechanism of this disease. A key regulatory component of the cell's hypoxia response system is hypoxia-inducible factor 1 alpha (HIF-1α). It has been demonstrated that the induction of HIF-1α expression can be also achieved in vitro by exposure with cobalt chloride (CoCl2), leading to an intracellular hypoxia-like state. In this study we have investigated the effects of CoCl2 on human retinal epithelium cells (hRPE), which are an integral part of the blood-retinal barrier, with the aim to determine the possible role of oxidative stress in chemical hypoxia-induced damage in retinal epithelial cells. Our data showed that CoCl2 treatment is able to induce HIF-1α expression, that parallels with the formation of reactive oxygen species (ROS) and the increase of lipid 8-isoprostanes and 4-hydroxynonenal (4-HNE) protein adducts levels. In addition we observed the activation of the redox-sensitive transcription factor nuclear factor-kappaB (NFkB) by CoCl2 which can explain the increased levels of vascular endothelial growth factor (VEGF). The increased number of dead cells seems to be related to an apoptotic process. Taken together these evidences suggest that oxidative stress induced by hypoxia might be involved in RD development through the stimulation of two key-events of RD such as neo-angiogenesis and apoptosis.

Ozonated oils as functional dermatological matrices: effects on the wound healing process using SKH1 mice

Wound tissue repair is a complex and dynamic process of restoring cellular structures and tissue layers. Improvement of this process is crucial for several pathologies characterized by chronic delayed wound closure such as diabetes, and the investigation of new approaches aimed to ameliorate the wound healing process is under continuous evolution. Recently, the usage of vegetable matrices in the form of ozonated oils has been proposed and several researchers have shown a positive effect in the wound, based on their bactericidal, antiviral, and antifungal properties. The present study was undertaken to compare the effect that different ozonated oils (olive, sesame and linseed) with the same level of ozonation have on wound healing rate in SKH1 mice. Several histological parameters and the level of key proteins such as VEGF and PCNA have been analyzed. Only treatment with ozonated sesame oil shows a faster wound closure in the first 7 days. This effect paralleled with the increased VEGF and PCNA levels, NFκB nuclear translocation and 4-HNE formation. The present study shows that not only the ozonation grade is of importance for the improvement of wound healing process but also the typical composition of the oil.

Rottlerin and cancer: novel evidence and mechanisms

Because cancers are caused by deregulation of hundreds of genes, an ideal anticancer agent should target multiple gene products or signaling pathways simultaneously. Recently, extensive research has addressed the chemotherapeutic potential of plant-derived compounds. Among the ever-increasing list of naturally occurring anticancer agents, Rottlerin appears to have great potentiality for being used in chemotherapy because it affects several cell machineries involved in survival, apoptosis, autophagy, and invasion. The underlying mechanisms that have been described are diverse, and the final, cell-specific, Rottlerin outcome appears to result from a combination of signaling pathways at multiple levels. This paper seeks to summarize the multifocal signal modulatory properties of Rottlerin, which merit to be further exploited for successful prevention and treatment of cancer.

Beta-carotene prevents ozone-induced proinflammatory markers in murine skin

Beta-carotene has been thought to protect against oxidative stress generated by ultraviolet radiation and thus prevents skin cancer and skin aging (Biesalski and Obermueller-Jevic, 2001). However, nothing is known about its potential effects against other environmental sources of oxidative stress such as ozone (O3) in skin. Intake of oral beta-carotene supplements before exposure to sunlight (and thus inevitably also to (O3) has been recommended on a population-wide basis. However, although some studies have shown beta-carotene as providing skin protection as an antioxidant, other studies using skin cells in culture have shown that beta-carotene may have unexpected prooxidant properties (Obermüller-Jevic, et al., 2001). Given this, there is an ongoing debate regarding the protective or potentially harmful role(s) of beta-carotene in human skin. In this study, the effect of beta-carotene on ozone's effects on the skin of hairless mice was assessed. After feeding a diet supplemented with 0.5% beta-carotene for 1 month, mice were subjected to O3 exposure (0.8 ppm 6 h/day; 7 days) and the induction of proinflammatory markers such as tumor necrosis factor-alpha (TNFalpha), macrophage inflammatory protein 2 (MIP2), and inducible nitric oxide synthase (iNOS), and markers of oxidative stress, heme-oxygenase-1 (HO-1), were quantitated. The data showed that beta-carotene downregulated the induction of TNFalpha, MIP2, iNOS, and HO-1 in response to O3. We conclude that beta-carotene provides protection against O3-induced skin oxidative stress in vivo, which is consistent with a protective role for beta-carotene in the skin.

Endothelin receptor A expression in human inflammatory cells

Most inflammatory diseases show elevated levels of endothelin-1 (ET-1) probably due to an alteration in vascular structure and function with activation/accumulation of inflammatory cells. The ET receptors (ET(A), ET(B)) are widely expressed in all human vessels, consistent with the main role of ET-1 in maintaining physiological vascular tone. Previous findings have shown the expression on inflammatory cells such as neutrophils (PMNs) and macrophages (MØs) of ET-1 and endothelin-converting enzyme-1 (ECE-1) (the key enzyme in the biosynthesis of ET-1). Therefore the role of ET-1 cannot be related only to the vasoactivity. Our study was aimed to determine the expression and the cellular location of ET receptors in both human PMNs and MØs by the use of RT-PCR assay, Western blot analysis and immunocytological methods. Our results showed for the first time that PMNs and MØs clearly expressed ET(A) (mRNA and protein). Considering that the overproduction of ET-1 following endothelial dysfunction and inflammation, contributes to pathophysiological processes such as vascular hypertrophy, cell proliferation and fibrosis, our results suggest that PMNs and MØs can also play a key role in vascular dysfunctions via the possible formation of an autocrine loop between ET-1 and ET(A).

Antiproliferative and survival properties of PMA in MCF-7 breast cancer cell

Although PKCs are assumed to be the main targets of phorbol esters (PMA), additional PMA effectors, such as chimaerins (a family of RacGTPase activating proteins) and RasGRP (exchange factor for Ras/Rap1), can counteract or strengthen the PKC pathways. In this study, we evaluated the proliferative behavior of PMA-treated MCF-7 breast cancer cell and found that: PMA induced growth arrest and inhibited cell death; PMA activated ERKs, which, in turn, induced p21; and inhibitors of ERK (PD98059) and PKC (GF109203X) prevented p21 induction and abolished the PMA survival effect. We conclude that PMA inhibits MCF-7 cell growth and simultaneously stimulates cell survival; both responses are linked to ERK-dependent and p53-independent p21 induction.

Rottlerin inhibits the nuclear factor kappaB/cyclin-D1 cascade in MCF-7 breast cancer cells

In the course of a project aimed to clarify the molecular mechanisms by which phorbol 12-myristate 13-acetate (PMA)-activated forms of protein kinase C (PKC) promote growth arrest in an MCF-7 cell line, we found that the PKCdelta inhibitor Rottlerin was able by itself to block cell proliferation. In the current study, we investigated further the antiproliferative response to Rottlerin. Western blotting analysis of cytoplasmic/nuclear extracts showed that the drug did not prevent either extracellular signal-regulated kinase (ERK) activation by PMA or Akt phosphorylation, but did interfere with the NFkappaB activation process (both basal and PMA-stimulated), by lowering the levels of phospho-IkappaBalpha and preventing p65 nuclear migration. The growth arrest evoked by Rottlerin was not mediated by cell-cycle inhibitors p21 and p27 but was accompanied by a dramatic fall in the cyclin-D1 protein, the levels of which were not altered by the pan-PKC inhibitor GF 109203X, thus excluding a PKC-mediated mechanism in the Rottlerin effect. The parallel drop in cyclin-D1 mRNA suggested a down-regulation of the gene caused by the inhibition of nuclear factor-kappa B (NFkappaB), which occurs via a PKC-, Akt-, ERK- and mitochondrial uncoupling-independent mechanism. We provide preliminary evidence that the interference on the NFkappaB activation process likely occurs at the level of calcium/calmodulin-dependent protein kinase II (CaMKII), a known Rottlerin target. Indeed the drug prevented calcium-induced CaMKII autophosphorylation which, in turn, led to decreased NFkappaB activation.

Studies on the biological effects of ozone: 9. Effects of ozone on human platelets

During the course of ozonated autohaemotherapy (O3-AHT) using heparin as an anticoagulant, it was occasionally observed that a few clots were retained in the filter during blood reinfusion. This observation prompted an investigation on the effect of ozone (O3) on human platelets. We have now shown, both by biochemical and morphological criteria, that heparin in the presence of O3 can promote platelet aggregation. In contrast, after Ca(2+) chelation with citrate, platelet aggregation is much reduced. The potential role of the transient formation of hydrogen peroxide (H2O2) in the presence of Ca2+ with the possible expression of adhesion molecules is briefly discussed.

The dual action of ozone on the skin

The aim of this brief review is to summarize the recent literature on the effect of ozone (O3) on cutaneous tissues. Recently it has been reported that a chronic contact with O3 can be deleterious for the skin. Our group and others have shown a progressive depletion of antioxidant content in the stratum corneum and this can then lead to a cascade of effects resulting in an active cellular response in the deeper layers of the skin. Using an in vivo model we have shown an increase of proliferative, adaptive and proinflammatory cutaneous tissue responses. On the other hand the well known activity of O3 as a potent disinfectant and oxygen (O2) donor has been also studied for therapeutic use. Two approaches have been described. The first consists of a quasi-total body exposure in a thermostatically controlled cabin. This treatment has proved to be useful in patients with chronic limb ischaemia. The second approach is based on the topical application of ozonated olive oil in several kinds of skin infection (from soreness to diabetic ulcers, burns, traumatic and surgical wounds, abscesses and skin reactions after radiotherapy). We and other authors have observed a striking cleansing effect with improved oxygenation and enhanced healing of these conditions. It is now clear that, on the skin, O3, like other drugs, poisons and radiation, can display either a damaging effect from a long exposure or a beneficial effect after a brief exposure to O2 and O3 or to the application of ozonated oil to chronic wounds.

ERKs are the point of divergence of PKA and PKC activation by PTHrP in human skin fibroblasts

Parathyroid hormone-related peptide (PTHrP) receptors, coupled to trimeric G proteins, operate in most target cells through at least three different transduction routes: Galpha s-mediated stimulation of adenylylcyclase (AC), Galpha q-mediated activation of phospholipase Cbeta (PLC) and mitogen-activated protein kinase (MAPK) activation. In this study we investigated the relative role of different pathways in human skin fibroblast proliferation. Using chemical inhibitors and activators of signal transduction, we demonstrated that: (i) AC/cAMP and PLC/1,4,5 inositol triphosphate/diacylglycerol second-messenger systems are simultaneously activated following PTHrP binding to its receptors; (ii) the mitogenic response to PTHrP derives from a balance between two counteracting pathways--an activating route mediated by protein kinase C (PKC) and an inhibitory route mediated by protein kinase A (PKA); (iii) PTHrP mitogenic effects are largely dependent on MAPKs, whose activity can be modulated by both PKA and PKC. Our results indicate that MAPKs are common targets of both transduction routes and, at the same time, their point of divergence in mediating PTHrP dual and opposite mitogenic effects.

Acrolein-induced cytotoxicity in cultured human bronchial epithelial cells. Modulation by alpha-tocopherol and ascorbic acid

Acrolein is a highly reactive unsaturated hazardous air pollutant of human health concern, particularly as a component of cigarette smoke. In this study, the mechanisms of acrolein-induced cytotoxicity in human bronchial epithelial cells (HBE1) and the modulating effects of antioxidants were examined. Our results show that acrolein induces a cell death pathway in human bronchial epithelial cells, which retain key features of apoptosis, as indicated by phosphatidylserine (PS) externalization and DNA fragmentation. Acrolein-induced apoptosis was associated with depletion of cellular GSH and intracellular generation of oxidants. Supplementation of cells with either alpha-tocopherol or ascorbic acid was found to strongly inhibit acrolein-induced apoptosis and to prevent the increase in the generation of intracellular oxidants, although GSH depletion was unaffected. Moreover, recovery of cellular GSH levels after acrolein exposure was enhanced following either alpha-tocopherol or ascorbic acid supplementation. The intracellular generation of oxidants following acrolein exposure seems to be an important event triggering the apoptotic response in this model system.

Effect of benzoyl peroxide on antioxidant status, NF-kappaB activity and interleukin-1alpha gene expression in human keratinocytes

Benzoyl peroxide (BP) is used as a topical treatment for acne. Besides its anti-bacterial activity, the exact molecular mechanisms underlying its mode of action are not fully understood. In the current study, the effects of BP on cell viability, antioxidant status and, IL-1 and IL-8 gene expression were investigated in HaCaT keratinocytes. Keratinocytes incubated for 24 h with BP exhibited a dose-dependent cytotoxicity at concentrations above 250 microM. Furthermore, in the presence of 300 microM BP about 50% of the cellular vitamin E was depleted within the first 30 min. The intracellular ratio of oxidized to reduced glutathione (GSSG/GSH) was increased significantly starting 6 h after BP treatments indicating that BP reacts rapidly with targets in the cell membrane and more slowly with those in the cytosol. NF-kappaB transactivation was not significantly affected by BP. However, BP treatment of HaCaT keratinocytes resulted in a dose-dependent increase in IL-1alpha gene expression whereas no changes in IL-8 mRNA levels were observed. These results demonstrate that BP induces an inflammatory reaction mediated by oxidative stress by a pathway independent of the redox-sensitive transcription factor NF-kappaB.

Macrophages stimulated with IFN-gamma activate NF-kappa B and induce MCP-1 gene expression in primary human endothelial cells

A novel coculture model was established to study the effects of reactive oxygen (ROS) and reactive nitrogen species (RNS) generated by RAW 264.7 macrophages on NF-kappa B activation and monocyte chemoattractant protein (MCP-1) gene expression in primary human endothelial cells (HUVEC). This model simulates free radical-mediated interactions occurring in the process of cardiovascular diseases. The coculture of macrophages grown on filters and stimulated by IFN-gamma-induced a pro-oxidant environment and resulted in increased DNA binding and NF-kappa B transactivation in HUVEC. Activation of NF-kappa B in endothelial cells was accompanied by an evident increase in the expression of the mRNA encoding for the MCP-1 protein, which stimulates the recruitment of monocytes into the arterial wall. Present data suggest that the influx of stimulated monocytes into the subendothelial space could affect redox-sensitive transcription factors and gene expression in the endothelium, thereby possibly leading to endothelial dysfunction.

Ozone potentiates vitamin E depletion by ultraviolet radiation in the murine stratum corneum

As the outermost layer of the skin, the stratum corneum is exposed to environmental oxidants. To investigate putative synergisms of environmental oxidative stressors in stratum corneum, hairless mice were exposed to ultraviolet radiation (UV) and ozone (O(3)) alone and in combination. Whereas a significant depletion of alpha-tocopherol was observed after individual exposure to either a 0.5 minimal erythemal dose of UV or 1 ppm O(3) for 2 h, the combination did not increase the effect of UV alone. However, a dose of 0.5 ppm O(3) x 2 h, which had no effect when used alone, significantly enhanced the UV-induced depletion of vitamin E. We conclude that concomitant exposure to low doses of UV and O(3) at levels near those that humans can be exposed to causes additive oxidative stress in the stratum corneum.

Activity of monomeric, dimeric, and trimeric flavonoids on NO production, TNF-alpha secretion, and NF-kappaB-dependent gene expression in RAW 264.7 macrophages

Flavonoids are potent antioxidants and have been associated with lowering the risk of cardiovascular diseases. In this study, the effect of flavonoids (monomers, dimers and a trimer) as well as French maritime pine bark extract, Pycnogenol, on NO production, tumor necrosis factor-alpha (TNF-alpha) secretion and nuclear factor (NF)-kappaB activity was compared. Monomers and dimers repressed NO production, TNF-alpha secretion and NF-kappaB-dependent gene expression induced by interferon gamma, whereas the trimeric procyanidin C2 and Pycnogenol enhanced these parameters. In addition, in unstimulated RAW 264.7 macrophages, both procyanidin C2 and Pycnogenol increased TNF-alpha secretion in a concentration- and time-dependent manner. These results demonstrate that procyanidins act as modulators of the immune response in macrophages.

Studies on the biological effects of ozone: 11. Release of factors from human endothelial cells

BACKGROUND

Empirical observations have shown that ozonated autohemotherapy markedly improves the symptoms of chronic limb ischemia (muscular pain at rest, intermittent claudication, etc) in atherosclerotic patients, but mechanisms of action remain unclear.

AIMS

Human endothelial cells (HUVECs) are known to release nitrogen monoxide (NO) and we investigated the biological effects of human ozonated serum on HUVECs in culture.

METHODS

We assessed the relevance of peroxidation, the release of NO as nitrite and of three classical cytokines.

RESULTS

The treatment of HUVECs with ozonated serum yields a dose dependent increase of thiobarbituric acid reactive substances (TBARS) and of hydrogen peroxide (H2O2) and a decrease of protein thiol groups (PTG). Concomitantly, in comparison to either the control or the oxygenated sample, there is a significant and steady increase of nitric oxide (NO) production; this is markedly enhanced by the addition of L-arginine (20 microM) and inhibited in the presence of the NO inhibitor, L-NAME (20 mM). The main mediator of ozone action is H2O2 as it has been shown either after its direct measurement or by the addition of 20, 40 and 100 microM. Moreover, during 24 hours incubation we have investigated the production of endothelin 1 (ET-1), E-selectin and Interleukin 8 (IL-8) and it appears that ozonation enhances IL-8, inhibits E-selectin and hardly modifies ET-1 production.

CONCLUSIONS

It appears that reinfusion of ozonated blood, by enhancing release of NO, may induce vasodilation in ischemic areas and reduce hypoxia.

Quasi-total-body exposure to an oxygen-ozone mixture in a sauna cabin

We have investigated the effects of quasi-total-body exposure of healthy volunteers to either an oxygen-ozone mixture (O(2)-O(3)) or to oxygen (O(2)) alone during a short period in a sauna cabin. The subjects underwent both an experimental and a control examination, separated by a 3.5-month interval. Body mass, blood pressure, body temperature changes, electrocardiograms, venous blood gas and haemocytometric analyses, total antioxidant status and plasma levels of protein thiol groups, thiobarbituric acid reactive substances (TBARS), plasma cytokine, hepatic enzymes and creatine were determined before, immediately after the 20-min period in the cabin and then 0.5, 1.0 and 24 h afterwards. We observed statistically significant variations of body temperature, venous partial pressure of O(2) values, TBARS and plasma levels of interleukin 8, particularly after O(2)-O(3) exposure. The increase in TBARS plasma levels concomitant with protein oxidation has been tentatively interpreted as being attributable to the transcutaneous passage of some reactive O(2) species, which should be considered if this approach is to be used as a biological response modifier. However, in the present study no adverse effects were noted after one session.

Ozonation of blood during extracorporeal circulation. I. Rationale, methodology and preliminary studies

We investigated whether exposure of blood ex-vivo to oxygen-ozone (O2-O3) through a gas exchanger is feasible and practical. We first evaluated the classical dialysis-type technique but we soon realized that semipermeable membranes are unsuitable because they are hydrophilic and vulnerable to O3. We therefore adopted a system with hydrophobic O3-resistant hollow fibers enclosed in a polycarbonate housing with a membrane area of about 0.5 m2. First we tested the system with normal saline, determining the production of hydrogen peroxide (H2O2) at O3 concentrations from 5 to 40 microg/ml. We then evaluated critical parameters by circulating swine blood in vitro; this revealed that heparin is not an ideal anticoagulant for this system. Finally, we performed several experiments in sheep and defined optimal anticoagulant dose (sodium citrate, ACD), priming solution, volume of blood flow per min, volume and concentration of O2-O3 mixture flowing countercurrent with respect to blood and the time necessary for perfusion in vivo. The biochemical parameters showed that an O3 concentration as low as 10 microg/ml is effective; this means that gas exchange and O3 reactivity are rapid and capable of inducing biological effects. The sheep showed no adverse effects even after 50 min of extracorporeal circulation at higher O3 concentrations (20 to 40 microg/ml) but the exchanger became less effective (low pO2 values) due to progressive clogging with cells.

Studies on the biological effects of ozone: 10. Release of factors from ozonated human platelets

In a previous work we have shown that heparin, in the presence of ozone (O3), promotes a dose-dependent platelet aggregation, while after Ca2+ chelation with citrate, platelet aggregation is almost negligible. These results led us to think that aggregation may enhance the release of platelet components. We have here shown that indeed significantly higher amount of platelet-derived growth factor (PDGF), transforming growth factor beta1 (TGF-beta1) and interleukin-8 (IL-8) are released in a dose-dependent manner after ozonation of heparinised platelet-rich plasma samples. These findings may explain the enhanced healing of torpid ulcers in patients with chronic limb ischemia treated with O3 autohaemoteraphy (O3-AHT).

Studies on the biological effects of ozone: 7. Generation of reactive oxygen species (ROS) after exposure of human blood to ozone

The acceptance of any complementary medical approach is conditioned by the results obtained after the same scientific scrutiny applied in orthodox medicine. Otherwise any claim of efficacy remains in the realm of fiction. In the case of ozone therapy, the mechanisms of action have remained nebulous and in a series of publications we are trying to present the biochemical, immunological and morphological evidence in favour or against ozone therapy. We have now shown that ozone (O3) dissolved in the water of either plasma or serum or physiological saline generates reactive oxygen species (ROS), of which hydrogen peroxide (H2O2) can be unequivocally demonstrated by using specific methods for its detection. Lipids present in plasma preferentially those present in lipoproteins, undergo peroxidation that is somewhat O3-dose dependent and can be observed by the measurement of thiobarbituric acid reactive substances (TBARS). While the generation of H2O2 is crucial in activating both biochemical (hexose monophosphate shunt) and immunological (via the transcription factor NF-kB) mechanisms, the role of lipid oxidation products (LOP) remains to be investigated. We have shown here that there is a small but consistent induction of some cytokines (TNF-alpha, IFN-gamma and IL-2) when human blood is directly exposed to O3 concentrations up to 100 micrograms/ml per g of blood. On the other hand, isolated blood mononuclear cells (PBMC) in tissue culture medium are far more sensitive to the oxidant action of O3 as shown by a progressive reduction of the proliferation index with comparatively far lower O3, concentrations. On the whole, these results support the concept that much of the O3 toxicity is neutralized by the powerful antioxidant system of blood. The minimal hemolysis supports this idea but as far as platelets are concerned, we must mention that they tend to aggregate in heparinized blood, even when it is exposed to an O3 concentration of 40 micrograms/ml. In spite of the lack of side-effects after autohemotherapy, this drawback must be kept in mind and avoided in clinical practice.

Studies on the biological effects of ozone: 8. Effects on the total antioxidant status and on interleukin-8 production

Ozone (O3) is a controversial gas because, owing to its potent oxidant properties, it exerts damaging effects on the respiratory tract and yet it has been used for four decades as a therapy. While the disinfectant activity of O3 is understandable, it is less clear how other biological effects can be elicited in human blood with practically no toxicity. On the other hand plasma and cells are endowed with a powerful antioxidant system so that a fairly wide range of O3 concentrations between 40 and 80 microg/ml per gram of blood (approximately 0.83-1.66 mM) are effective but not deleterious. After blood ozonation total antioxidant status (TAS) and plasma protein thiol groups (PTG) decrease by 20% and 25%, respectively, while thiobarbituric acid reactive substances (TBARS) increases up to five-fold. The increase of haemolysis is negligible suggesting that the erythrocyte membrane is spared at the expense of other sacrificial substrates. While there is a clear relationship between the ozone dose and IL-8 levels, we have noticed that high TAS and PTG values inhibit the cytokine production. This is in line with the current idea that hydrogen peroxide, as a byproduct of O3 decomposition, acts as a messenger for the cytokine induction.