Thalamocortical bistable switch as a theoretical model of fibromyalgia pathogenesis inferred from a literature survey.

Fibromyalgia (FM) is an unsolved central pain processing disturbance. We aim to provide a unifying model for FM pathogenesis based on a loop network involving thalamocortical regions, i.e., the ventroposterior lateral thalamus (VPL), the somatosensory cortex (SC), and the thalamic reticular nucleus (TRN). The dynamics of the loop have been described by three differential equations having neuron mean firing rates as variables and containing Hill functions to model mutual interactions among the loop elements. A computational analysis conducted with MATLAB has shown a transition from monostability to bistability of the loop behavior for a weakening of GABAergic transmission between TRN and VPL. This involves the appearance of a high-firing-rate steady state, which becomes dominant and is assumed to represent pathogenic pain processing giving rise to chronic pain. Our model is consistent with a bulk of literature evidence, such as neuroimaging and pharmacological data collected on FM patients, and with correlations between FM and immunoendocrine conditions, such as stress, perimenopause, chronic inflammation, obesity, and chronic dizziness. The model suggests that critical targets for FM treatment are to be found among immunoendocrine pathways leading to GABA/glutamate imbalance having an impact on the thalamocortical system.

Brown-Algae Polysaccharides as Active Constituents against Nonalcoholic Fatty Liver Disease.

Nonalcoholic fatty liver disease is a metabolic disorder characterized by lipid overloading in hepatocytes that can progress pathogenically and even end in hepatocellular carcinoma. Nonalcoholic fatty liver disease pharmacological treatment is still limited by unwanted side effects, whereas the use of food components with therapeutic potential is advisable. The culinary use of marine algae is traditional for some populations and reviving worldwide, with promising health outcomes due to the large number of bioactive compounds found in seaweeds. The present review focuses on brown-algae polysaccharides, particularly fucoidan, alginate, and laminarin, and summarizes the experimental evidence of their potential effects against nonalcoholic fatty liver disease onset and progression. In vitro and in vivo studies demonstrate that brown-algae polysaccharides exert beneficial actions on satiety feeling, caloric intake, fat absorption, and modulation of the gut microbiota, which could account for indirect effects on energy and lipid homeostasis, thus diminishing the fat overload in the liver. Specific effects against nonalcoholic fatty liver disease pathogenesis and worsening are also described and sustained by the antioxidant, anti-inflammatory, and antisteatotic properties of brown-algae polysaccharides. Further studies are required to clarify the mechanism of action of brown-algae polysaccharides on liver cells, to determine the composition and bioavailability of brown-algae polysaccharides present in different algal sources and to probe the clinical availability of these compounds in the form of algal foods, food supplements, and regulated therapeutics.

First Evidence of Anti-Steatotic Action of Macrotympanain A1, an Amphibian Skin Peptide from Odorrana macrotympana.

Many different amphibian skin peptides have been characterized and proven to exert various biological actions, such as wound-healing, immunomodulatory, anti-oxidant, anti-inflammatory and anti-diabetic effects. In this work, the possible anti-steatotic effect of macrotympanain A1 (MA1) (FLPGLECVW), a skin peptide isolated from the Chinese odorous frog Odorrana macrotympana, was investigated. We used a well-established in vitro model of hepatic steatosis, consisting of lipid-loaded rat hepatoma FaO cells. In this model, a 24 h treatment with 10 µg/mL MA1 exerted a significant anti-steatotic action, being able to reduce intracellular triglyceride content. Accordingly, the number and diameter of cytosolic lipid droplets (LDs) were reduced by peptide treatment. The expression of key genes of hepatic lipid metabolism, such as PPARs and PLINs, was measured by real-time qPCR. MA1 counteracted the fatty acid-induced upregulation of PPARγ expression and increased PLIN3 expression, suggesting a role in promoting lipophagy. The present data demonstrate for the first time a direct anti-steatotic effect of a peptide from amphibian skin secretion and pave the way to further studies on the use of amphibian peptides for beneficial actions against metabolic diseases.

Antioxidant and Antisteatotic Activities of Fucoidan Fractions from Marine and Terrestrial Sources.

Fucoidan is a fucose-rich sulfated polysaccharide typically found in the cell wall of marine algae but also recently isolated from terrestrial sources. Due to a variety of biological activities, including antioxidant properties, fucoidan exhibits an attractive therapeutic potential against a wide array of metabolic diseases associated with oxidative stress. We used FTIR, 1H NMR and 13C NMR spectroscopy to investigate the structural features of a fucoidan fraction extracted from the brown alga Cystoseira compressa (CYS). The antioxidant potential of CYS was measured by DPPH, ABTS and FRAP assays, which revealed a radical scavenging capacity that was confirmed in in vitro cellular models of hepatic and endothelial cells. The same antioxidant effects were observed for another fucoidan fraction previously identified in the terrestrial tree Eucalyptus globulus (EUC). Moreover, in hepatic cells, CYS and EUC exhibited a significant antisteatotic action, being able to reduce intracellular triglyceride content through the regulation of key genes of hepatic lipid metabolism. EUC exerted stronger antioxidant and antisteatotic effects as compared to CYS, suggesting that both marine and terrestrial sources should be considered for fucoidan extraction and therapeutic applications.

Antioxidant and Antisteatotic Activities of a New Fucoidan Extracted from Ferula hermonis Roots Harvested on Lebanese Mountains.

Fucoidan is a fucose-rich sulfated polysaccharide with attractive therapeutic potential due to a variety of biological activities, including antioxidant action. Fucoidan is typically found in the cell wall of marine brown algae, but extra-algal sources have also been discovered. In the present work, for the first time we extracted a water soluble fucoidan fraction from the roots of the terrestrial shrub Ferula hermonis. This fucoidan fraction was termed FUFe, and contained fucose, glucose, sulfate, smaller amounts of monosaccharides such as galactose and mannose, and a minor quantity of proteins. FUFe structural features were investigated by FTIR, 1H NMR and 13C NMR spectroscopy. The antioxidant property of FUFe was measured by DPPH, ABTS and FRAP assays, which revealed a high radical scavenging capacity that was confirmed in in vitro cellular models. In hepatic and endothelial cells, 50 µg/mL FUFe could reduce ROS production induced by intracellular lipid accumulation. Moreover, in hepatic cells FUFe exhibited a significant antisteatotic action, being able to reduce intracellular triglyceride content and to regulate the expression of key genes of hepatic lipid metabolism. Altogether, our results candidate FUFe as a possible bioactive compound against fatty liver disease and related vascular damage.

Synthesis, Photoisomerization, Antioxidant Activity, and Lipid-Lowering Effect of Ferulic Acid and Feruloyl Amides.

The Ugi four-component reaction employing naturally occurred ferulic acid (FA) is proposed as a convenient method to synthesize feruloyl tertiary amides. Applying this strategy, a peptoid-like derivative of ferulic acid (FEF77) containing 2 additional hydroxy-substituted aryl groups, has been synthesized. The influence of the configuration of the double bond of ferulic acid and feruloyl amide on the antioxidant activity has been investigated thanks to light-mediated isomerization studies. At the cellular level, both FA, trans and cis isomers of FEF77 were able to protect human endothelial cord vein (HECV) cells from the oxidative damage induced by exposure to hydrogen peroxide, as measured by cell viability and ROS production assays. Moreover, in steatotic FaO rat hepatoma cells, an in vitro model resembling non-alcoholic fatty liver disease (NAFLD), the molecules exhibited a lipid-lowering effect, which, along with the antioxidant properties, points to consider feruloyl amides for further investigations in a therapeutic perspective.

Peptides for Skin Protection and Healing in Amphibians.

Amphibian skin is not to be considered a mere tegument; it has a multitude of functions related to respiration, osmoregulation, and thermoregulation, thus allowing the individuals to survive and thrive in the terrestrial environment. Moreover, amphibian skin secretions are enriched with several peptides, which defend the skin from environmental and pathogenic insults and exert many other biological effects. In this work, the beneficial effects of amphibian skin peptides are reviewed, in particular their role in speeding up wound healing and in protection from oxidative stress and UV irradiation. A better understanding of why some species seem to resist several environmental insults can help to limit the ongoing amphibian decline through the development of appropriate strategies, particularly against pathologies such as viral and fungal infections.

Models of non-Alcoholic Fatty Liver Disease and Potential Translational Value: the Effects of 3,5-L-diiodothyronine.

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in industrialized countries and is associated with increased risk of cardiovascular, hepatic and metabolic diseases. Molecular mechanisms on the root of the disrupted lipid homeostasis in NAFLD and potential therapeutic strategies can benefit of in vivo and in vitro experimental models of fatty liver. Here, we describe the high fat diet (HFD)-fed rat in vivo model, and two in vitro models, the primary cultured rat fatty hepatocytes or the FaO rat hepatoma fatty cells, mimicking human NAFLD. Liver steatosis was invariably associated with increased number/size of lipid droplets (LDs) and modulation of expression of genes coding for key genes of lipid metabolism such as peroxisome proliferator-activated receptors (Ppars) and perilipins (Plins). In these models, we tested the anti-steatotic effects of 3,5-L-diiodothyronine (T2), a metabolite of thyroid hormones. T2 markedly reduced triglyceride content and LD size acting on mRNA expression of both Ppars and Plins. T2 also stimulated mitochondrial oxidative metabolism of fatty acids. We conclude that in vivo and especially in vitro models of NAFLD are valuable tools to screen a large number of compounds counteracting the deleterious effect of liver steatosis. Because of the high and negative impact of liver steatosis on human health, ongoing experimental studies from our group are unravelling the ultimate translational value of such cellular models of NAFLD.

Fibromyalgia pathogenesis explained by a neuroendocrine multistable model.

Fibromyalgia (FM) is a central disorder characterized by chronic pain, fatigue, insomnia, depression, and other minor symptoms. Knowledge about pathogenesis is lacking, diagnosis difficult, clinical approach puzzling, and patient management disappointing. We conducted a theoretical study based on literature data and computational analysis, aimed at developing a comprehensive model of FM pathogenesis and addressing suitable therapeutic targets. We started from the evidence that FM must involve a dysregulation of central pain processing, is female prevalent, suggesting a role for the hypothalamus-pituitary-gonadal (HPG) axis, and is stress-related, suggesting a role for the HP-adrenocortical (HPA) axis. Central pathogenesis was supposed to involve a pain processing loop system including the thalamic ventroposterolateral nucleus (VPL), the primary somatosensory cortex (SSC), and the thalamic reticular nucleus (TRN). For decreasing GABAergic and/or increasing glutamatergic transmission, the loop system crosses a bifurcation point, switching from monostable to bistable, and converging on a high-firing-rate steady state supposed to be the pathogenic condition. Thereafter, we showed that GABAergic transmission is positively correlated with gonadal-hormone-derived neurosteroids, notably allopregnanolone, whereas glutamatergic transmission is positively correlated with stress-induced glucocorticoids, notably cortisol. Finally, we built a dynamic model describing a multistable, double-inhibitory loop between HPG and HPA axes. This system has a high-HPA/low-HPG steady state, allegedly reached in females under combined premenstrual/postpartum brain allopregnanolone withdrawal and stress condition, driving the thalamocortical loop to the high-firing-rate steady state, and explaining the connection between endocrine and neural mechanisms in FM pathogenesis. Our model accounts for FM female prevalence and stress correlation, suggesting the use of neurosteroid drugs as a possible solution to currently unsolved problems in the clinical treatment of the disease.

Online Questionnaire with Fibromyalgia Patients Shows Negative Correlations between Disease Severity and Adherence to Mediterranean Diet.

Fibromyalgia (FM) is a multidimensional disorder in which intense chronic pain is accompanied by a variety of psychophysical symptoms that impose a burden on the patients' quality of life. Despite the efforts and the recent advancement in research, FM pathogenesis and effective treatment remain unknown. Recently, the possible role of dietary patterns and/or components has been gaining attention. The current study aimed to investigate a potential correlation between adherence to the Mediterranean diet (MedDiet) and FM severity in a sample of Italian FM patients. An online survey was designed, composed of customized questions and validated questionnaires with the aim of investigating the intensity and type of pain, the presence of other psychophysical symptoms, the overall impact of FM, general food and lifestyle habits, and adherence to the MedDiet. The collected responses were analyzed for descriptive statistics, linear regression, and propensity score analyses. The results show that, despite considerable use of pharmaceuticals and supplements, FM participants suffered from a high-severity grade disease. However, those with good adherence to the MedDiet experienced a lower pain intensity and overall FM impact. A propensity score analysis indicates a positive influence of the MedDiet against FM severity, thus unveiling the need for well-designed intervention studies to evaluate the therapeutic potential of different dietary patterns.

The Role of the Stress Response in Metabolic Dysfunction-Associated Fatty Liver Disease: A Psychoneuroendocrineimmunology-Based Perspective.

The novel term metabolic dysfunction-associated fatty liver disease (MAFLD), which has been proposed to describe the major cause of hepatic disease, pinpoints the coexistence of multiple metabolic disturbances and liver steatosis, giving rise to different phenotypic manifestations. Within the psychoneuroendocrineimmunological (PNEI) network that regulates body-mind interactions, the stress response plays a pervasive role by affecting metabolic, hormonal, immune, and behavioral balance. In this perspective, we focus on chronic psychosocial stress and high levels of cortisol to highlight their role in MAFLD pathogenesis and worsening. From a PNEI perspective, considering the stress response as a therapeutic target in MAFLD allows for simultaneously influencing multiple pathways in the development of MAFLD, including dysmetabolism, inflammation, feeding behaviors, gut-liver axis, and dysbiosis, with the hope of better outcomes.

Fibromyalgia in Pregnancy: Neuro-Endocrine Fluctuations Provide Insight into Pathophysiology and Neuromodulation Treatment.

Fibromyalgia (FM) is a chronic pain disorder with unclear pathophysiological mechanisms, which leads to challenges in patient management. In addition to pain, the disorder presents with a broad range of symptoms, such as sleep disruption, chronic fatigue, brain fog, depression, muscle stiffness, and migraine. FM has a considerable female prevalence, and it has been shown that symptoms are influenced by the menstrual cycle and periods of significant hormonal and immunological changes. There is increasing evidence that females with FM experience an aggravation of symptoms in pregnancy, particularly during the third trimester and after childbirth. In this perspective paper, we focus on the neuro-endocrine interactions that occur between progesterone, allopregnanolone, and cortisol during pregnancy, and propose that they align with our previously proposed model of FM pathogenesis based on GABAergic "weakening" in a thalamocortical neural loop system. Based on our hypothesis, we introduce the possibility of utilizing transcranial direct current stimulation (tDCS) as a non-invasive treatment potentially capable of exerting sex-specific effects on FM patients.

An extensive review on phenolic compounds and their potential estrogenic properties on skin physiology.

Polyphenolic compounds constitute a diverse group of natural components commonly occurring in various plant species, known for their potential to exert both beneficial and detrimental effects. Additionally, these polyphenols have also been implicated as endocrine-disrupting (ED) chemicals, raising concerns about their widespread use in the cosmetics industry. In this comprehensive review, we focus on the body of literature pertaining to the estrogenic properties of ED chemicals, with a particular emphasis on the interaction of isoflavones with estrogen receptors. Within this review, we aim to elucidate the multifaceted roles and effects of polyphenols on the skin, exploring their potential benefits as well as their capacity to act as ED agents. By delving into this intricate subject matter, we intend to provoke thoughtful consideration, effectively opening a Pandora's box of questions for the reader to ponder. Ultimately, we invite the reader to contemplate whether polyphenols should be regarded as friends or foes in the realm of skincare and endocrine disruption.

Online Questionnaire with Fibromyalgia Patients Reveals Correlations among Type of Pain, Psychological Alterations, and Effectiveness of Non-Pharmacological Therapies.

Fibromyalgia (FM) is a chronic pain syndrome with an unclear etiology. In addition to pain, FM patients suffer from a diverse array of symptoms and comorbidities, encompassing fatigue, cognitive dysfunction, mood disorders, sleep deprivation, and dizziness. Due to the complexity of FM, the diagnosis and treatment of it are highly challenging. The aim of the present work was to investigate some clinical and psychological characteristics of FM patients, and to uncover possible correlations with pharmacological and non-pharmacological therapies. We conducted a cross-sectional, questionnaire-based study aimed at evaluating pain, psychological traits, and the self-perceived effectiveness of pharmacological and non-pharmacological treatments in an Italian population of FM patients. Descriptive statistics, correlation, and inference analyses were performed. We found a prevalence of a neuropathic/nociplastic type of pain, which correlated with psychological traits such as anxiety, low mood, psychophysical discomfort, and the inability to relax. The pain type and psychological traits proved to play a role in determining the self-perceived effectiveness of therapeutic interventions. Patients revealed a better response to non-pharmacological therapies, particularly dietary interventions, relaxation techniques, and psychotherapy rather than pharmacological interventions. The sum of our data indicates that for better outcomes, the type of pain and psychological traits should be considered for tailor-made treatments considering non-pharmacological protocols as a complement to the use of drugs.

Vestibular Disability/Handicap in Fibromyalgia: A Questionnaire Study.

Fibromyalgia (FM) is a poorly understood, central pain processing disorder characterized by a broad range of symptoms, such as chronic pain, sleep disruption, chronic fatigue, and psychosomatic symptoms. In addition, recent studies have shown that FM patients also experience dizziness. We aimed to establish a prevalence rate of vestibular symptoms in a population of FM patients through a battery of questionnaires investigating socio-demographic, clinical and psychological characteristics, combined with the Dizziness Handicap Inventory (DHI) and the Situational Vertigo Questionnaire (SVQ). A total of 277 respondents, officially diagnosed with FM, completed the full study, while 80 controls were also included for DHI and SVQ questionnaires. We found that FM participants were significantly affected by vestibular symptoms, which correlated with FM-associated pain and non-pain symptoms. The dizziness reported by FM participants showed peculiar features suggesting an FM-intrinsic mechanism of vestibular dysfunction, possibly linked to migraine and dysautonomia conditions. Correlations between dizziness and depressive mood (or neuroticism), revealed an impact of dizziness on psychological status, leading to depressive reactions and interpersonal difficulties, and possibly involving a noxious, self-sustained stress condition. In conclusion, data showed a manifesting dizziness condition in FM patients that warrants careful clinical attention due to its possible inherent role in the syndrome.

Innovative In Vitro Strategy for Assessing Aluminum Bioavailability in Oral Care Cosmetics.

Aluminum is an element found in nature and in cosmetic products. It can interfere with the metabolism of other cations, thus inducing gastrointestinal disorder. In cosmetics, aluminum is used in antiperspirants, lipsticks, and toothpastes. The aim of this work is to investigate aluminum bioavailability after accidental oral ingestion derived from the use of a toothpaste containing a greater amount of aluminum hydroxide than advised by the Scientific Committee on Consumer Safety (SCCS). To simulate in vitro toothpaste accidental ingestion, the INFOGEST model was employed, and the amount of aluminum was measured through the ICP-AES analysis. Tissue barrier integrity was analyzed by measuring transepithelial electric resistance, and the tissue architecture was checked through light microscopy. The margin of safety was also calculated. Overall, our results indicate that the acute exposure to aluminum accidentally ingested from toothpastes is safe for the final user, even in amounts higher than SCCS indications.

Ischemia-reperfusion damage is attenuated by GQ-11, a peroxisome proliferator-activated receptor (PPAR)-α/γ agonist, after aorta clamping in rats.

INTRODUCTION: Ischemia-Reperfusion (I/R) damage is one of the major challenges in cardiothoracic surgeries and in a pathological manner, is identified by exacerbated damage signals resulted from blood supply restriction and subsequent flow restoration and re­oxygenation. I/R damage includes cellular dysfunction and death, impairing tissue and organ function. Inflammation and oxidative stress are known to underlie either ischemia or reperfusion, leaded by HIF, TNF-α, NF-κB, IL-6 and ROS formation. However, the available approaches to prevent I/R damage has been unsuccessful so far. As agonists of peroxisome-proliferation activation receptor (PPAR) are described as transcription factors related to anti-inflammatory factors, we proposed to observe the effects of novel dual agonist, GQ-11, in I/R-related damage. METHODS: Male, Wistar rats, 60 days age and 305 g body weight average were treated with vehicle, pioglitazone or GQ-11 (20 mg/kg) for 7 consecutive days and were submitted to aorta clamping for 30 min followed by 3 h of reperfusion. 18F-fluorodeoxyglucose (18F-FDG), an analog of glucose associated with inflammation when accumulated, was observed in liver and bowel by positron emission tomography (PET). RESULTS: GQ-11 decreased 18F-FDG uptake in liver and bowel when compared to vehicle and pioglitazone. The treatment also modulated inflammatory markers IL-10, TGF-ß, IL-6, IL1-ß, TNFα, and CCL-2, besides antioxidant enzymes such as catalase, GPx and SOD. CONCLUSION: Inflammation and oxidative stress showed to be important processes to be regulated in I/R in order to prevent exacerbated responses that leads to cell/tissue dysfunction and death. PPAR agonists - including GQ-11 - might be promising agents in a strategy to avoid tissue dysfunction and death after cardiothoracic surgeries.

Expression of antioxidant defense and poly(ADP-ribose) polymerase-1 in rat developing Sertoli cells.

Sertoli cells play an essential role in the development of a functional testis. ROS (reactive oxygen species) are normally produced by the developing testicular cells and may be dangerous to spermatogenesis. The aim of this study was to investigate the developmental expression of genes involved in antioxidant defense as well as in the DNA damage response in rat Sertoli cells. As revealed by quantitative RT-PCR analysis, the expression pattern of the antioxidant enzymes GST (glutathione-S-transferase), CAT (catalase) and SOD (superoxide dismutase) showed a progressive decrease from birth to puberty. The expression level of the oncosuppressor p53 revealed a net reduction as well. We next focused on PARP-1 [poly(ADP-ribose) polymerase-1], a 'guardian of the genome' that combats stress conditions. At both the mRNA and protein level, PARP-1 expression was low at the early stage of development and increased later on. Maximal PARP-1 expression was preceded by a rise in the transcript level for MTs (metallothioneins), which provide zinc to zinc-dependent enzymes and proteins, including PARP-1. Our results showed an increased expression of PARP-1 during Sertoli cell development, together with a decrease in the expression of antioxidant enzymes. In conclusion, a role of PARP-1 in protecting the testicular differentiation is suggested.

Effects of winter sea bathing on psychoneuroendocrinoimmunological parameters.

CONTEXT: Many people claim winter sea bathing gives them energy and health. According to the psychoneuroendocrinoimmunology (PNEI) paradigm, the stress response elicited by cold water immersion could indeed induce several beneficial psychophysical alterations. OBJECTIVE: To determine the effects of winter sea bathing on psychological wellbeing, stress and immune markers. DESIGN: A cross-sectional study. PARTICIPANTS: 228 people, between 19 and 88 years, including 107 winter sea bathers and 121 controls. MAIN OUTCOME MEASURES: A battery of questionnaires was administered to assess sociodemographic characteristics, self-perception of mental and physical heath, the number, duration and intensity of Upper Respiratory Tract Infections (URTIs) in the last year, and Big Five personality traits. 17 winter sea bathers and 15 controls (mean age 67 years) were further examined to evaluate physiological health, underwent one ear-nose-throat (ENT) examination, and provided saliva samples for measurements of biological markers (cortisol, sIgA, IL-1ß, IL-6). RESULTS: Winter sea bathing was associated with lower levels of self-reported stress and higher wellbeing. The ENT examinations did not reveal signs of URTIs in winter sea bathers, who exhibited significantly higher levels of salivary sIgA compared to controls. Neither salivary IL-1ß nor cortisol levels were significantly different between the two groups. CONCLUSIONS: Winter sea bathers (even the elderly) had a perception of higher wellbeing and reported better health: thus, they appeared to take advantage of potential distress (cold water exposure) to improve their health.

Uncoupling protein-2 induction in rat hepatocytes after acute carbon tetrachloride liver injury.

This study is focused on the role of UCP-2 in hepatic oxidative metabolism following acute CCl(4) administration to rats. UCP-2 mRNA, almost undetectable in the liver of controls, was significantly increased 24 h after CCl(4) administration, peaked at 72 h and then tended to disappear. UCP-2 protein, undetectable in controls, increased 48-72 h after CCl(4) treatment. Experiments with isolated liver cells indicated that in control rats UCP-2 was expressed in non-parenchymal cells and not in hepatocytes, whereas in CCl(4)-treated rats UCP-2 expression was induced in hepatocytes and was not affected in non-parenchymal cells. Addition of CCl(4) to the culture medium of hepatocytes from control rats failed to induce UCP-2 expression. Liver mitochondria from CCl(4)-treated rats showed an increase of H(2)O(2) release at 12-24 h, followed by a rise of TBARS. Vitamin E protected liver from CCl(4) injury and reduced the expression of UCP-2. Treatment with GdCl(3) prior to CCl(4), in order to inhibit Kupffer cells, reduced TBARS and UCP-2 mRNA increase in hepatic mitochondria. Our data indicate that CCl(4) induces the expression of UCP-2 in hepatocytes with a redox-dependent mechanism involving Kupffer cells. A role of UCP-2 in moderating CCl(4)-induced oxidative stress during tissue regeneration after injury is suggested.