A short Mindfulness retreat can improve biological markers of stress and inflammation.

OBJECTIVE: Mindfulness practice, a form of meditation, has shown benefit for psychological and physical health. In this study, we investigated the effect of an intensive period of Mindfulness practice on some biological mediators of stress and inflammation during a 3-day residential retreat. METHODS: A total of 95 healthy individuals (aged 18-67) were recruited and randomized to a Mindfulness retreat arm or an active control arm. Before (t0) and after (t1) the intervention, all the participants were assessed for salivary cortisol levels and for a panel of pro- and anti-inflammatory cytokines measured in saliva. Psychometric measures on stress, anxiety and awareness were carried out using PSS, STAI-Y and MAAS questionnaires, respectively. RESULTS: As to the within-group differences, we observed a statistically significant decrease in perceived stress (ß = -8.85, p < 0.0001), and anxiety scores (ß = -12.39, p < 0.0001), while awareness increased (ß = 15.26, p < 0.0001) between t0 to t1 in retreat participants. In the mindfulness intervention group, we also observed a statistically significant reduction in the levels of pro-inflammatory cytokines IL-6 (ß = -0.94 p = 0.001) and IL-8 (ß = -176.40, p < 0.0001), and an increase in anti-inflammatory IL-10 (ß = 0.89 p < 0.0001) levels at the end of the retreat. At t1 we observed a highly significant correlation between cortisol levels and both anxiety (r = 0.56, p < 0.0001) and perceived stress (r = 0.92, p < 0.0001) scores. CONCLUSIONS: Mindfulness retreat participants showed a significant reduction in perceived stress and anxiety levels, as well as an improved balance of some key mediators of inflammatory states. Our data provide evidence that a mindfulness retreat may be effective in improving physical and mental health. Future studies with larger numbers of subjects and follow-up periods may examine mindfulness practice as a non-pharmacological alternative to promote stress reduction and overall health and wellbeing.

Mindfulness-based stress reduction training modulates striatal and cerebellar connectivity.

Mindfulness is a meditation practice frequently associated with changes in subjective evaluation of cognitive and sensorial experience, as well as with modifications of brain activity and morphometry. Aside from the anatomical localization of functional changes induced by mindfulness practice, little is known about changes in functional and effective functional magnetic resonance imaging (fMRI) connectivity. Here we performed a connectivity fMRI analysis in a group of healthy individuals participating in an 8-week mindfulness-based stress reduction (MBSR) training program. Data from both a "mind-wandering" and a "meditation" state were acquired before and after the MBSR course. Results highlighted decreased local connectivity after training in the right anterior putamen and insula during spontaneous mind-wandering and the right cerebellum during the meditative state. A further effective connectivity analysis revealed (a) decreased modulation by the anterior cingulate cortex over the anterior portion of the putamen, and (b) a change in left and right posterior putamen excitatory input and inhibitory output with the cerebellum, respectively. Results suggest a rearrangement of dorsal striatum functional and effective connectivity in response to mindfulness practice, with changes in cortico-subcortical-cerebellar modulatory dynamics. Findings might be relevant for the understanding of widely documented mindfulness behavioral effects, especially those related to pain perception.

Hepatitis C virus eradication by direct antiviral agents abates oxidative stress in patients with advanced liver fibrosis.

BACKGROUND AND AIMS: HCV eradication improves non-hepatic outcomes such as cardiovascular diseases, although without clearly defined mechanisms. In this study we aimed to assess whether improvement of carotid atherosclerosis may be linked to a reduction in systemic oxidative stress after viral clearance. METHODS: We studied a retrospective cohort of 105 patients (age 62.4 ± 11.2 years; 62 men) with F3/F4 fibrosis, characterized by carotid ultrasonography at baseline and at sustained virologic response (SVR) follow-up. Levels of 8-iso-prostaglandin F2α (F2 -isoprostanes) and other oxidative stress markers were measured on frozen sera. Association between change (denoted as Δ) in oxidative stress markers (exposures) and change in carotid intima-media thickness (cIMT) (outcome) was examined using multiple linear regression. RESULTS: Subclinical atherosclerosis, defined as the presence of carotid plaque and/or cIMT ≥ 0.9, was present in 72% of the cohort. All patients achieved SVR that led to reduction in cIMT (0.92 ± 0.20 vs 0.83 ± 0.21 mm, P < .001). HCV eradication markedly decreased serum levels of F2 -isoprostanes (620.5 [143.2; 1904.1] vs 119.51 [63.2; 400.6] pg/mL, P < .0001), lipid hydroperoxides (13.8 [6.3; 20.7] vs 4.9 [2.3; 9.6] nmol/µl, P < .0001) and 8-hydroxy-2'-deoxyguanosine (558.9 [321.0; 6301.2] vs 294.51 [215.31; 408.95] pg/mL, P < .0001), whereas increased serum GPx activity (10.44 [4.6; 16.3] vs 13.75 [9.42; 20.63] nmol/min/mL, P = .001). By multiple linear regression analysis ΔcIMT was independently associated with ΔF2 -isoprostanes (ß: 1.746 [0.948; 2.543]; P < .0001) after adjustment for age, baseline F2 -isoprostanes and baseline IMT. CONCLUSIONS: Besides association of lipid peroxidation with severity of liver disease, the reduction in F2 -isoprostanes may be involved in the improvement of atherosclerosis after HCV eradication.

Correction: Cigarette Smoke Affects Keratinocytes SRB1 Expression and Localization via H2O2 Production and HNE Protein Adducts Formation.

[This corrects the article DOI: 10.1371/journal.pone.0033592.].

F2-isoprostanes can mediate bleomycin-induced lung fibrosis.

F2-isoprostanes (F2-IsoPs) have been considered markers of oxidative stress in various pulmonary diseases, but little is known about their possible role in pulmonary fibrosis. In this study, we have investigated the potential key role of F2-IsoPs as markers and mediators of bleomycin (BLM)-induced pulmonary fibrosis in rats. During the in vivo study, plasma F2-IsoPs showed a peak at 7 days and remained elevated for the entire experimental period. Lung F2-IsoP content nearly tripled 7 days following the intratracheal instillation of BLM, and by 28 days, the value increased about fivefold compared to the controls. Collagen deposition correlated with F2-IsoP content in the lung. Furthermore, from day 21 onwards, lung sections from BLM-treated animals showed α-smooth muscle actin (α-SMA) positive cells, which were mostly evident at 28 days. In vitro studies performed in rat lung fibroblasts (RLF) demonstrated that either BLM or F2-IsoPs stimulated both cell proliferation and collagen synthesis. Moreover, RLF treated with F2-IsoPs showed a significant increase of α-SMA expression compared to control, indicating that F2-IsoPs can readily activate fibroblasts to myofibroblasts. Our data demonstrated that F2-IsoPs can be mediators of key events for the onset and development of lung fibrosis, such as cell proliferation, collagen synthesis and fibroblast activation. Immunocytochemistry analysis, inhibition and binding studies demonstrated the presence of the thromboxane A2 receptor (TP receptor) on lung fibroblasts and suggested that the observed effects may be elicited through the binding to this receptor. Our data added a new perspective on the role of F2-IsoPs in lung fibrosis by providing evidence of a profibrotic role for these mediators in the pathogenesis of pulmonary fibrosis.

Alteration of serum lipid profile, SRB1 loss, and impaired Nrf2 activation in CDKL5 disorder.

CDKL5 mutation is associated with an atypical Rett syndrome (RTT) variant. Recently, cholesterol homeostasis perturbation and oxidative-mediated loss of the high-density lipoprotein receptor SRB1 in typical RTT have been suggested. Here, we demonstrate an altered lipid serum profile also in CDKL5 patients with decreased levels of SRB1 and impaired activation of the defensive system Nrf2. In addition, CDKL5 fibroblasts showed an increase in 4-hydroxy-2-nonenal- and nitrotyrosine-SRB1 adducts that lead to its ubiquitination and probable degradation. This study highlights a possible common denominator between two different RTT variants (MECP2 and CDKL5) and a possible common future therapeutic target.

Animal models for anti-emphysema drug discovery.

INTRODUCTION: Emphysema is characterized by an abnormal and permanent enlargement of airspaces accompanied by destruction of their walls. Up to now, there is no cure for emphysema, and animal models may be important for new drug discovery. AREAS COVERED: Herein, the authors review animal models of emphysema since the protease-antiprotease hypothesis as well as the results obtained with compounds tested in these models. Of particular importance are animal models of cigarette smoke exposure since it is the most important risk factor of emphysema. The authors also analyze two approaches to drug testing, that is, the approach aimed at preventing emphysema and the one aimed at reversing it. EXPERT OPINION: It has been suggested that early and late interventions do not have the same protective effect and that late interventions are much more likely to reveal treatments beneficial in humans. However, this is not always the case, and a compound that prevents emphysema when administered as an early intervention can also have the same protective effect when given as a late intervention. Furthermore, the fact that a compound detected by means of early intervention is now in clinical practice shows that early intervention studies can be predictive for efficacy in humans.

Markers of inflammation and oxidative stress studied in adjuvant-induced arthritis in the rat on systemic and local level affected by pinosylvin and methotrexate and their combination.

Oxidative stress (OS) is important in the pathogenesis of autoimmune diseases such as rheumatoid arthritis (RA) and its experimental model--adjuvant arthritis (AA). Antioxidants are scarcely studied in autoimmunity, and future analyses are needed to assess its effects in ameliorating these diseases. Although there are studies about antioxidants effects on the course of RA, their role in combination therapy has not yet been studied in detail, especially on extra-articular manifestations of AA. During the 28-d administration of pinosylvin (PIN) in monotherapy and in combination with methotrexate (MTX) to AA rats, we evaluated the impact of the treatment on selected parameters. The experiment included: healthy controls, untreated AA, AA administered 50 mg/kg b.w. of PIN daily p.o., AA administered 0.4 mg/kg b.w. of MTX twice weekly p.o. and AA treated with a combination of PIN+MTX. AA was monitored using: hind paw volume, C-reactive protein, monocyte chemotactic protein-1 (MCP-1), thiobarbituric acid reactive substances (TBARS) and F2-isoprostanes in plasma, γ-glutamyltransferase activity in spleen, activity of lipoxygenase (LOX) in lung, heme oxygenase-1 (HO-1) and nuclear factor kappa B (NF-κB) in liver and lung. PIN monotherapy significantly improved the activation of NF-κB in liver and lung, HO-1 expression and activity of LOX in the lung, MCP-1 levels in plasma (on 14th d) and plasmatic levels of F2-isoprostanes. An important contribution of PIN to MTX effect was the reduction of OS (an increase of HO-1 expression in lung and reduction of plasmatic TBARS) and decrease of LOX activity in the lung.

Interaction between neuroanatomical and psychological changes after mindfulness-based training.

Several cross-sectional studies have documented neuroanatomical changes in individuals with a long history of meditation, while a few evidences are available about the interaction between neuroanatomical and psychological changes even during brief exposure to meditation. Here we analyzed several morphometric indexes at both cortical and subcortical brain level, as well as multiple psychological dimensions, before and after a brief -8 weeks- Mindfulness Based Stress Reduction (MBSR) training program, in a group of 23 meditation naïve-subjects compared to age-gender matched subjects. We found a significant cortical thickness increase in the right insula and the somatosensory cortex of MBSR trainees, coupled with a significant reduction of several psychological indices related to worry, state anxiety, depression and alexithymia. Most importantly, an interesting correlation between the increase in right insula thickness and the decrease in alexithymia levels during the MBSR training were observed. Moreover, a multivariate pattern classification approach allowed to identify a cluster of regions more responsive to MBSR training across subjects. Taken together, these findings documented the significant impact of a brief MBSR training on brain structures, as well as stressing the idea of MBSR as a valuable tool for alexithymia modulation, also originally providing a plausible neurobiological evidence of a major role of right insula into mediating the observed psychological changes.

N-feruloylserotonin in preventive combination therapy with methotrexate reduced inflammation in adjuvant arthritis.

Many of disease-modifying anti-rheumatic drugs often have side effects at high doses and/or during long-term administration. Increased efficacy without increased toxicity is expected for combination therapy of rheumatoid arthritis (RA). The aim of the study was to examine the effect of N-feruloylserotonin (N-f-5HT) and methotrexate (MTX) in monotherapy and in combination therapy on disease progression and inflammation in arthritic rats. Adjuvant arthritis was induced by intradermal injection of Mycobacterium butyricum in incomplete Freund's adjuvant in Lewis rats. The experiment included healthy animals, arthritic animals without any drug administration, arthritic animals with administration of N-f-5HT in the oral daily dose of 15 mg/kg b.w., arthritic animals with administration of MTX in the oral dose of 0.3 mg/kg b.w. twice a week and arthritic animals treated with the combination of N-f-5HT and MTX. N-f-5HT in monotherapy reduced only activation of NF-κB and did not have any significant effect on other parameters monitored. Low-dose treatment of MTX decreased the level of IL-1ß and MCP-1 on day 14 and activation of NF-κB in liver without significant effect on other parameters. N-f-5HT and MTX combination showed both the anti-arthritic (hind paw volume and arthritic score) and anti-inflammatory effect (plasmatic levels of IL-1ß, IL-17, MCP-1, CRP, and activation of NF-κB in liver). In combination with MTX, N-f-5HT markedly potentiated the therapeutic effect of MTX low dose, which resulted in significant improvement of all parameters measured. The findings showed that the combination therapy simultaneously decreased multiple markers of inflammation, a result crucial for future therapy of RA.

Downregulation of NOX4 expression by roflumilast N-oxide reduces markers of fibrosis in lung fibroblasts.

The phosphodiesterase 4 inhibitor roflumilast prevents bleomycin- (BLM-) induced lung fibrosis in animal models. However, its mechanism of action remains unknown. We investigated whether roflumilast N-oxide (RNO), the active metabolite of roflumilast, can modulate in vitro the oxidative effects of BLM on human lung fibroblasts (HLF). In addition, since BLM increases the production of F2-isoprostanes that have per se fibrogenic activity, the effect of RNO on oxidative stress and fibrogenesis induced by the F2-isoprostane 8-epi-PGF2α was investigated. HLF were preincubated either with the vehicle or with RNO and exposed to either BLM or 8-epi-PGF2α. Proliferation and collagen synthesis were assessed as [(3)H]-thymidine and [(3)H]-proline incorporation. Reactive oxygen species (ROS) and F2-isoprostanes were measured. NADPH oxidase 4 (NOX4) protein and mRNA were also evaluated. BLM increased both cell proliferation and collagen synthesis and enhanced ROS and F2-isoprostane production. These effects were significantly prevented by RNO. Also, RNO significantly reduced the increase in both NOX4 mRNA and protein, induced by BLM. Finally, 8-epi-PGF2α per se stimulated HLF proliferation, collagen synthesis, and NOX4 expression and ROS generation, and RNO prevented these effects. Thus, the antifibrotic effect of RNO observed in vivo may be related to its ability to mitigate ROS generation via downregulation of NOX4.

Signaling pathways involved in isoprostane-mediated fibrogenic effects in rat hepatic stellate cells.

Despite evidence supporting a potential role for F2-isoprostanes (F2-IsoP's) in liver fibrosis, their signaling mechanisms are poorly understood. We have previously provided evidence that F2-IsoP's stimulate hepatic stellate cell (HSC) proliferation and collagen hyperproduction by activation of a modified form of isoprostane receptor homologous to the classic thromboxane receptor (TP). In this paper, we examined which signal transduction pathways are set into motion by F2-IsoP's to exert their fibrogenic effects. HSCs were isolated from rat liver, cultured to their activated myofibroblast-like phenotype, and then treated with the isoprostane 15-F2t-isoprostane (15-F2t-IsoP). Inositol trisphosphate (IP3) and adenosine 3',5'-cyclic monophosphate (cAMP) levels were determined using commercial kits. Mitogen-activated protein kinase (MAPK) and cyclin D1 expression was assessed by Western blotting. Cell proliferation and collagen synthesis were determined by measuring [(3)H]thymidine and [(3)H]proline incorporation, respectively. 15-F2t-IsoP elicited an activation of extracellular-signal-regulated kinase (ERK), p38 MAPK, and c-Jun NH2-terminal kinase (JNK), which are known to be also regulated by G-protein-coupled receptors. Preincubation with specific ERK (PD98059), p38 (SB203580), or JNK (SP600125) inhibitors prevented 15-F2t-IsoP-induced cell proliferation and collagen synthesis. 15-F2t-IsoP decreased cAMP levels within 30 min, suggesting binding to the TPß isoform and activation of Giα protein. Also, 15-F2t-IsoP increased IP3 levels within a few minutes, suggesting that the Gq protein pathway is also involved. In conclusion, the fibrogenic effects of F2-IsoP's in HSCs are mediated by downstream activation of MAPKs, through TP binding that couples via both Gqα and Giα proteins. Targeting TP receptor, or its downstream pathways, may contribute to preventing oxidative damage in liver fibrosis.

NRF2 activation is involved in ozonated human serum upregulation of HO-1 in endothelial cells.

During the last decade, it has been shown that the activation of NRF2 and the binding to electrophile-responsive element (EpREs), stimulates the expression of a great number of genes responsible for the synthesis of phase I and phase II proteins, including antioxidants enzymes and heme oxygenase-1 (HO-1). This critical cell response occurs in cardiovascular, degenerative and chronic infective diseases aggravated by a chronic oxidative stress. In our previous reports we have shown that ozonated plasma is able to up-regulate HO-1 expression in endothelial cells. In the present work we investigated a candidate mechanism involved in this process. After treatment with increasing doses of ozonated serum (20, 40 and 80 µg/mL O(3) per mL of serum), a clear dose dependent activation of NRF2 and the subsequent induction of HO-1 and NAD(P)H quinone oxidoreductase 1(NQO1) was observed. This effect was also present when cells were treated with serum and hydrogen peroxide (H(2)O(2)) or serum and 4-hydroxynonenal (4HNE). Moreover, the treatment with ozonated serum was associated with a dose-dependent activation of extracellular-signal-regulated kinases (ERK1/2) and p38 MAP kinases (p38), not directly involved in NRF2 activation. These data, provide a new insight on the mechanism responsible for the induction of HO-1 expression by ozonated serum in the endothelium, and have a practical importance as an expedient approach to the treatment of patients with both effective orthodox drugs and ozonated autohemotherapy, targeted to the restoration of redox homeostasis.

Cigarette smoke and ozone effect on murine inflammatory responses.

Air pollution has been associated with many different diseases, such as cancer, and respiratory, cardiovascular, and cutaneous chronic diseases. These effects are enhanced in people exposed to combined air pollutants, such as ozone and cigarette smoke. Chronic exposure to these pollutants causes an increase in oxidative stress and inflammation and has been associated with an increase in pulmonary diseases and mortality. Clinical and epidemiological studies reported interindividual variability in the adverse health effects of air pollutants, suggesting a genetic predisposition. The identification of subgroups of the population who are particularly vulnerable to air pollution is, therefore, of importance. Mouse models are a useful tool for studying the mechanisms underlying different susceptibility, as they show differences in strain responses to both ozone and cigarette smoke. This review analyses the role of inflammation and the influence of genetic factors on the mechanisms of lung injury caused by ozone and cigarette smoke.

Cigarette smoke affects keratinocytes SRB1 expression and localization via H2O2 production and HNE protein adducts formation.

Scavenger Receptor B1 (SR-B1), also known as HDL receptor, is involved in cellular cholesterol uptake. Stratum corneum (SC), the outermost layer of the skin, is composed of more than 25% cholesterol. Several reports support the view that alteration of SC lipid composition may be the cause of impaired barrier function which gives rise to several skin diseases. For this reason the regulation of the genes involved in cholesterol uptake is of extreme significance for skin health. Being the first shield against external insults, the skin is exposed to several noxious substances and among these is cigarette smoke (CS), which has been recently associated with various skin pathologies. In this study we first have shown the presence of SR-B1 in murine and human skin tissue and then by using immunoblotting, immunoprecipitation, RT-PCR, and confocal microscopy we have demonstrated the translocation and the subsequent lost of SR-B1 in human keratinocytes (cell culture model) after CS exposure is driven by hydrogen peroxide (H(2)O(2)) that derives not only from the CS gas phase but mainly from the activation of cellular NADPH oxidase (NOX). This effect was reversed when the cells were pretreated with NOX inhibitors or catalase. Furthermore, CS caused the formation of SR-B1-aldheydes adducts (acrolein and 4-hydroxy-2-nonenal) and the increase of its ubiquitination, which could be one of the causes of SR-B1 loss. In conclusion, exposure to CS, through the production of H(2)O(2), induced post-translational modifications of SR-B1 with the consequence lost of the receptor and this may contribute to the skin physiology alteration as a consequence of the variation of cholesterol uptake.

Ethanol-induced oxidative stress: basic knowledge.

After a general introduction, the main pathways of ethanol metabolism (alcohol dehydrogenase, catalase, coupling of catalase with NADPH oxidase and microsomal ethanol-oxidizing system) are shortly reviewed. The cytochrome P(450) isoform (CYP2E1) specifically involved in ethanol oxidation is discussed. The acetaldehyde metabolism and the shift of the NAD/NADH ratio in the cellular environment (reductive stress) are stressed. The toxic effects of acetaldehyde are mentioned. The ethanol-induced oxidative stress: the increased MDA formation by incubated liver preparations, the absorption of conjugated dienes in mitochondrial and microsomal lipids and the decrease in the most unsaturated fatty acids in liver cell membranes are discussed. The formation of carbon-centered (1-hydroxyethyl) and oxygen-centered (hydroxyl) radicals during the metabolism of ethanol is considered: the generation of hydroxyethyl radicals, which occurs likely during the process of univalent reduction of dioxygen, is highlighted and is carried out by ferric cytochrome P(450) oxy-complex (P(450)-Fe(3+)O(2) (.-)) formed during the reduction of heme-oxygen. The ethanol-induced lipid peroxidation has been evaluated, and it has been shown that plasma F(2)-isoprostanes are increased in ethanol toxicity.

Reactivity of mouse alveolar macrophages to cigarette smoke is strain dependent.

Cigarette smoke (CS) is a main risk factor in chronic obstructive pulmonary disease (COPD), but only 20% of smokers develop COPD, suggesting genetic predisposition. Animal studies have shown that C57BL/6J mice are sensitive to CS and develop emphysema, whereas Institute of Cancer Research (ICR) mice are not. To investigate the potential factors responsible for the different susceptibility of ICR and C57BL/6J mice to CS, we evaluated in alveolar macrophages (AMs) isolated from these strains of mice the possible mechanisms involved in the inflammatory and oxidative responses induced by CS. Lactate dehydrogenase (LDH) release revealed that C57BL/6J AMs were more susceptible to CS extract (CSE) toxicity than ICR. Differences were observed in inflammatory and oxidative response after CSE exposure. Proinflammatory cytokines and matrix metalloproteinases (MMPs) were increased in C57BL/6J but not ICR AMs. Control C57BL/6J AMs showed a higher baseline production of reactive oxygen species (ROS) and H(2)O(2) with lower baseline levels of GSH, nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and glutathione peroxidase (GPX2). This was associated with reduced histone deacetylase-2 (HDAC2) expression, activation of NF-κB, and higher basal levels of TNF-α and IL-6. CSE induced a decrease in HDAC2 protein levels in both C57BL/6J and ICR AMs; however, the level of HDAC2 was significantly lower in C57BL/6 than in ICR AMs. Furthermore, CSE enhanced NF-κB-dependent cytokine release only in C57BL/6J AMs. We suggest that an imbalance in oxidative stress decreases HDAC2 levels and facilitates NF-κB binding, resulting in a proinflammatory response in C57BL/6J but not in ICR AMs. These results could contribute in understanding the different susceptibility to CS of these strains of mice.

Oxidative stress, isoprostanes and hepatic fibrosis.

An introduction to oxidative stress enlightening the spreading of interest in lipid peroxidation in the 60's and in the identification of cytotoxic aldehydes originating from it is given. The discovery of F2-isoprostanes as specific markers of oxidative stress is described. Isoprostanes are also agonists of important biological effects. Since a relationship between oxidative stress and collagen hyperproduction has been previously suggested, and since lipid peroxidation products (aldehydes) have been proposed as possible mediators of liver fibrosis, we investigated whether collagen synthesis is induced by F2-isoprostanes, which can possess receptors for signal transduction pathways. In a rat model of carbon tetrachloride-induced hepatic fibrosis, plasma isoprostanes were markedly elevated for the entire experimental period and hepatic collagen content was also increased. Moreover, when hepatic stellate cells (HSC) isolated from normal livers were cultured up to activation and then treated with F2-isoprostanes (8-epi-PGF2alpha) in the concentration range found in the in vivo studies (10(-9) to 10(-8) M), a striking increase in DNA synthesis, in cell proliferation and in collagen synthesis was observed. F2-isoprostanes also increased the production of transforming growth factor-beta1 by U937 cells, assumed as a model of Kupffer cells or liver macrophages. The hypothesis that F2-isoprostanes generated by lipid peroxidation in hepatocytes mediate HSC proliferation and collagen hyperproduction, seen in this experimental hepatic fibrosis, was reinforced by the demonstration, by using immunoblot analysis, that isoprostane receptors identical or analogous to those for thromboxane A2 (TxA2r) are present in HSC. Immunocytochemical studies showed the major localization of TxA2r in the perinuclear site and its colocalization with alpha-smooth muscle actin.

Testing of compounds in models of pulmonary emphysema.

There is a pressing need for the development of new therapies for emphysema, particularly as no existing treatment has been shown to reduce disease progression. Compounds with a potential activity against the pathological mechanisms postulated to play a role in the development and progression of emphysema should be tested in vivo in animal models of this disease. The choice of the model is of capital importance. While models of elastase-induced emphysema are relatively easy to execute, require low personnel capacity and provide fast results, they also have a limited clinical relevance. On the other hand, models of chronic smoke exposure are time-consuming, expensive and require high personnel capacity but have a high clinical relevance. Presently, mainly two pharmacological approaches are being considered and investigated in experimental studies. The first approach consists of pharmacological interventions designed to slow down the rate at which alveolar wall is lost in emphysema. In this approach we find anti-inflammatory agents, protease inhibitors and antioxidants. The attempt to reduce lung inflammatory cell infiltration is most appealing since such an effect would also reduce the lung burden of both proteases and oxidants. The second approach is an attempt to reverse the process of alveolar loss by inducing alveolar growth. To our knowledge here only the effects of retinoids and/or retinoid receptor agonists have been investigated. This report presents a selected review of the literature of animal studies using these pharmacological approaches.