Maria Cristina Mele

Growth-inhibitory effects of the astaxanthin-rich alga Haematococcus pluvialis in human colon cancer cells.

The growth-inhibitory effects of the astaxanthin-rich Haematococcus pluvialis were studied in HCT-116 colon cancer cells. H. pluvialis extract (5-25 microg/ml) inhibited cell growth in a dose- and time-dependent manner, by arresting cell cycle progression and by promoting apoptosis. At 25 microg/ml of H. pluvialis extract, an increase of p53, p21(WAF-1/CIP-1) and p27 expression (220%, 160%, 250%, respectively) was observed, concomitantly with a decrease of cyclin D1 expression (58%) and AKT phosphorylation (21%). Moreover, the extract, at the same concentration, strongly up-regulated apoptosis by modifying the ratio of Bax/Bcl-2 and Bcl-XL, and increased the phosphorylation of p38, JNK, and ERK1/2 by 160%, 242%, 280%, respectively. Growth-inhibitory effects by H. pluvialis were also observed in HT-29, LS-174, WiDr, SW-480 cells. This study suggests that H. pluvialis may protect from colon cancer.

Lycopene prevents 7-ketocholesterol-induced oxidative stress, cell cycle arrest and apoptosis in human macrophages.

The present study was undertaken to examine whether lycopene is able to counteract 7-ketocholesterol (7-KC)-induced oxidative stress and apoptosis in human macrophages. Human THP-1 macrophages were exposed to 7-KC (10-25 microM) alone and in combination with lycopene (0.5-2 microM), and we monitored changes in cell oxidative status [reactive oxygen species (ROS) production, NOX-4, hsp70 and hsp90 expressions, 8-OHdG formation] and in cell proliferation and apoptosis. After 24 h of treatment, lycopene significantly reduced the increase in ROS production and in 8-OHdG formation induced by the oxysterol in a dose-dependent manner. Moreover, the carotenoid strongly prevented the increase of NOX-4, hsp70 and hsp90 expressions as well as the phosphorylation of the redox-sensitive p38, JNK and ERK1/2 induced by the oxysterol. The attenuation of 7-KC-induced oxidative stress by lycopene coincided with a normalization of cell growth in human macrophages. Lycopene prevented the arrest in G0/G1 phase of cell cycle induced by the oxysterol and counteracted the increased expression of p53 and p21. Concomitantly, it inhibited 7-KC-induced apoptosis, by limiting caspase-3 activation and the modulatory effects of 7-KC on AKT, Bcl-2, Bcl-xL and Bax. Comparing the effects of lycopene, beta-carotene and (5Z)-lycopene on ROS production, cell growth and apoptosis show that lycopene and its isomer were more effective than beta-carotene in counteracting the dangerous effects of 7-KC in human macrophages. Our study suggests that lycopene may act as a potential antiatherogenic agent by preventing 7-KC-induced oxidative stress and apoptosis in human macrophages.

Lycopene prevention of oxysterol-induced proinflammatory cytokine cascade in human macrophages: inhibition of NF-κB nuclear binding and increase in PPARγ expression.

It is now well accepted that oxysterols play important roles in the formation of atherosclerotic plaque, involving cytotoxic, pro-oxidant and proinflammatory processes. It has been recently suggested that tomato lycopene may act as a preventive agent in atherosclerosis, although the exact mechanism of such a protection is not clarified. The main aim of this study was to investigate whether lycopene is able to counteract oxysterol-induced proinflammatory cytokines cascade in human macrophages, limiting the formation of atherosclerotic plaque. Therefore, THP-1 macrophages were exposed to two different oxysterols, such as 7-keto-cholesterol (4-16 μM) and 25-hydroxycholesterol (2-4 μM), alone and in combination with lycopene (0.5-2 μM). Both oxysterols enhanced pro-inflammatory cytokine [interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor α) secretion and mRNA levels in a dose-dependent manner, although at different extent. These effects were associated with an increased reactive oxygen species (ROS) production through an enhanced expression of NAD(P)H oxidase. Moreover, a net increment of phosphorylation of extracellular regulated kinase 1/2, p-38 and Jun N-terminal kinase and of nuclear factor kB (NF-κB) nuclear binding was observed. Lycopene prevented oxysterol-induced increase in pro-inflammatory cytokine secretion and expression. Such an effect was accompanied by an inhibition of oxysterol-induced ROS production, mitogen-activated protein kinase phosphorylation and NF-κB activation. The inhibition of oxysterol-induced cytokine stimulation was also mimicked by the specific NF-κB inhibitor pyrrolidine dithiocarbamate. Moreover, the carotenoid increased peroxisome proliferator-activated receptor γ levels in THP-1 macrophages. Taken all together, these data bring new information on the anti-atherogenic properties of lycopene, and on its mechanisms of action in atherosclerosis prevention.

Tomato Lycopene and Lung Cancer Prevention: From Experimental to Human Studies

Increasing evidence suggests that tomato lycopene may be preventive against the formation and the development of lung cancer. Experimental studies demonstrated that lycopene may inhibit the growth of several cultured lung cancer cells and prevent lung tumorigenesis in animal models through various mechanisms, including a modulation of redox status, cell cycle arrest and/or apoptosis induction, a regulation of growth factor signaling, changes in cell growth-related enzymes, an enhancement of gap junction communication and a prevention of smoke-induced inflammation. In addition, lycopene also inhibited cell invasion, angiogenesis, and metastasis. Several lycopene metabolites have been identified, raising the question as to whether the preventive effects of lycopene on cancer risk is, at least in part, due to its metabolites. Despite these promising reports, it is difficult at the moment to directly relate available experimental data to human pathophysiology. More well controlled clinical intervention trials are needed to further clarify the exact role of lycopene in the prevention of lung cancer cell growth. Such studies should take into consideration subject selection, specific markers of analysis, the levels of carotenoids being tested, metabolism and isomerization of lycopene, interaction with other bioactive food components. This article reviews data on the cancer preventive activities of lycopene, possible mechanisms involved, and the relationship between lycopene consumption and human cancer risk.

Effect of Lycopene and Tomato Products on Cholesterol Metabolism

Background/Aims: Increased ingestion of tomato, containing lycopene, has been associated with a decreased risk for atherosclerosis, although the exact molecular mechanism is still unknown. Here we review the available evidence for a direct regulation of tomato lycopene on cholesterol metabolism using results from experimental and human studies. Results: In human macrophages lycopene dose dependently reduced intracellular total cholesterol. Such an effect was associated with a decrease in cholesterol synthesis through a reduction of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and expression, a modulation of low- density lipoprotein (LDL) receptor and acyl-coenzyme A:cholesterol acyltransferase activity. An increase in cholesterol efflux through an enhancement of ABCA1 and caveolin-1 expression was also observed. In animal models of atherosclerosis, lycopene and tomato products decreased plasma total cholesterol, LDL cholesterol and increased high-density lipoprotein cholesterol. In agreement with the experimental results, most human intervention trials analyzed show that dietary supplementation with lycopene and/or tomato products reduced plasma LDL cholesterol dependently on the dose and the time of administration. Conclusions: Although lycopene and tomato products seem to possess direct hypocholesterolemic properties, more experimental studies are needed to better understand the mechanisms involved. There is also a need for more well-designed human dietary intervention studies to better clarify the role of lycopene as a hypocholesterolemic agent.

Bioelectrical impedance analysis during pregnancy and neonatal birth weight

OBJECTIVE To generate reference ranges for bioelectrical impedance indices throughout pregnancy and to investigate whether a relationship exists between these indices and the neonatal birth weight. STUDY DESIGN Pregnant women with a singleton gestation, gestational age lower than 12 weeks, and absence of medical diseases before pregnancy were enrolled. Patients with pregnancy complications, such as hypertensive disorders, diabetes, and antiphospholipides syndrome were excluded. Antrophometric maternal parameters and bioelectrical impedance measurements were performed during the first, second, third trimester of pregnancy, at delivery and 60 days after delivery. Height(2)/resistance (cm(2)/Omega) and height(2)/reactance (cm(2)/Omega) were utilized to estimate the total and extracellular body water amounts, respectively. Spearman rank correlations and cox proportional hazard modelling were used for statistical purposes. RESULTS 169 patients completed all measurements. Total and extracellular water amounts significantly increase as pregnancy advances and return to the pre-pregnancy values within 60 days after delivery. After adjustment for gestational age at delivery, fetal sex, and smoking habits, height(2)/resistance at 25 weeks (hazard=1.04, 95% confidence interval (CI) 1.02-1.06, P<0.005), height(2)/resistance at 30 weeks (hazard=1.03, 95% CI 1.01-1.05, P<0.005), height(2)/reactance at 20 weeks (hazard=1.03,95% CI 1.01-1.05, P<0.005), and height(2)/reactance at 25 weeks (hazard=1.03, 95% CI 1.01-1.04, P<0.01) were found to be independent predictors of birth weight. CONCLUSION We have provided reference ranges for bioimpedance analysis during pregnancy, an easy, fast and non invasive method to estimate the body water composition during pregnancy. Bioelectrical impedance indices during the second trimester of pregnancy are independently related to the birth weight.

High total antioxidant activity and uric acid in tracheobronchial aspirate fluid of preterm infants during oxidative stress: an adaptive response to hyperoxia?

The effect of O2 exposure, expressed by mean daily fractional inspired oxygen concentration (FiO2), was evaluated during the first 6 d of life in the tracheobronchial aspirate fluid of 16 mechanically ventilated preterm infants in terms of both antioxidant response and oxidative damage, by measuring total antioxidant activity, uric acid concentrations and protein carbonyl content. Each day linear regression analysis was performed and a positive correlation was found between total antioxidant activity and FiO2 during the study period, especially on day 2 of life (r= 0.91, p < 0.0001), but uric acid correlated only in the first 3 d, especially on the 2nd day (r= 0.83, p < 0.0001). No correlation was found between carbonyl content and FiO2. The highest values of total antioxidant activity (416 and 790 μmol l−1) were found in 2 babies ventilated with highest FiO2: 1 and 0.80, respectively. Total antioxidant activity was not detectable or was very low in the babies not requiring O2 therapy. The highest value of uric acid (270 μmol l−1) was found in the baby ventilated with 100% oxygen. Uric acid concentrations obtained in these babies were much higher then those reported in the bronchoalveolar lavage fluid of adults.

Interplay of Carotenoids with Cigarette Smoking: Implications in Lung Cancer

The potential for carotenoids to modulate chronic diseases related to smoke is currently under investigation and renewed interest has been placed on achieving a better understanding of the mechanism(s) of action of carotenoids in smoke-exposed biological systems. Available data currently show that, while carotenoids alone are not harmful, their interaction with smoke may shift from beneficial to detrimental depending on the dose, the type of carotenoid as well as the biological environment in which they act. Several mechanisms have been proposed to explain such a shift. They include: (i) changes in cell oxidative status, which tips the beta-carotene antioxidant- prooxidant balance toward a prooxidant status; (ii) modulation of the levels of key proteins involved in the regulation of cell proliferation and apoptosis; (iii) reduction of retinoic acid signal pathway which down-regulates the RARbeta expression and up-regulates AP-1; (iv) interference with absorption of other nutrients at better antioxidant profile; (v) formation of specific carotenoid oxidation products. This review summarizes the available evidences in cultured cells, animal models and humans for a modulatory action of carotenoids on the dangerous effects of smoke and focuses on the main molecular pathways involved in this process.

Metabolism of c9,t11-conjugated linoleic acid (CLA) in humans

The c9,t11 isomer of conjugated linoleic acid (CLA) is the most abundant CLA form present in the human diet, and is particularly prevalent in milk and dairy products, and is known to exert several health benefits in experimental animal models. A possible mechanism of action of c9,t11CLA relies on its metabolism via desaturases and elongases and partial beta oxidation in peroxisomes. In this study, we aimed to establish plasma incorporation of c9,t11CLA and its downstream metabolites in healthy volunteers after daily dietary intakes of 0.8g, 1.6g or 3.2g of c9,t11CLA in capsule form for two months. Following supplementation, the plasma concentrations of c9,t11CLA and its metabolites conjugated dienes (CD) 18:3 and the beta oxidation product CD 16:2 were incorporated in a linear fashion, while on the other hand CD 20:3 reached a plateau following intakes of 1.6g/d of dietary intake, and was not further increased following higher CLA intakes. We may conclude that supplementation of c9,t11 CLA levels result in linear responses of CLA and its main metabolites in plasma. In addition, only the highest concentration of CLA intake tested (3.2g/d) yielded plasma concentrations of CLA and metabolites close to the range found sufficient to exert nutritional effects in experimental animal models.

Modulation of MMP-9 pathway by lycopene in macrophages and fibroblasts exposed to cigarette smoke.

Matrix metalloproteinase-9 (MMP-9) has been implicated in both inflammation and fibrosis. It has been reported that cigarette smoke induced MMP-9 expression and that lycopene may act as an anti-inflammatory agent and may counteract several signal pathways affected by cigarette smoke exposure. However, at the moment, it is unknown if lycopene may inhibit cigarette smoke-induced MMP-9 expression. Presently, we examined the inhibitory mechanism of lycopene on MMP-9 induction in cultured human macrophages (THP-1 cells), in isolated rat alveolar macrophages (AMs) and in cultured RAT-1 fibroblasts, all cellular sources of MMP-9, exposed to cigarette smoke extract (CSE). CSE induced a marked increase in MMP-9 expression in cultured as well as in isolated cells. A 8 h-lycopene pre-treatment (0.5-2 μM) reduced CSE-mediated MMP-9 induction in a dose- and time-dependent manner. Lycopene attenuated CSE-mediated activation of Ras, enhancing the levels of this protein in the cytosolic fraction. Moreover, lycopene inhibited CSE-induced ERK1/2 and NF-κB activation in a dose-dependent manner. Lycopene-mediated inhibition of MMP-9 was reversed by mevalonate and associated with a reduced expression of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. Taken together, these results suggest that lycopene may inhibit CSE-mediated MMP-9 induction, primarily by blocking prenylation of Ras in a signaling pathway, in which MEK1/2-ERK1/2 and NF-κB are involved.