Biomedical subjects

P Ghezzi

Publications and source records attributed to P Ghezzi.

At least 19 recordsLinked to original sources

PubMed2001

Role of cytokines in cancer cachexia in a murine model of intracerebral injection of human tumours.

To study the role of cytokines that are relevant in cancer cachexia syndrome due to intracerebral tumours, mice were injected with human A431 epidermoid carcinoma, OVCAR3 ovarian carcinoma and GBLF glioma cells comparing intracerebral (i.c.) and systemic (i.p. or s.c.) routes of implantation. Anorexia and weight loss developed within 7-10 days in mice injected i.c. with A431 or OVCAR3 cells well before a large tumour developed, while i.c.-injected GBLF cells did not induce cachexia until day 20, when the tumour was large. By contrast, mice injected i.p. or s.c. developed tumours without evidence of anorexia. Thus, intracerebrally-growing A431 and OVCAR3 resulted in cancer cachexia independent of tumour mass, and we investigated their cytokine pattern. Serum levels of murine and human cytokines are not predictive of cancer cachexia development. Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis revealed in the brain of i.c.-injected A431 tumour-bearing mice expression of human interleukin-(IL-)1alpha, IL-1beta and LIF in all samples and IL-6 in two of four samples while in i.c.-injected OVCAR3 tumour-bearing animals IL-6, and LIF were detected in all samples and tumour necrosis factor-alpha (TNFalpha) in two of four samples. Only LIF was expressed in brains of mice injected with GBLF cells. Murine IL-6 was increased only in the brains of A431-bearing mice. Only mice injected i.c. simultaneously with a monoclonal antibody (mAb) directed against the murine IL-6 receptor and OVCAR3 cells, but not those with mAb and A431 cells, showed a significant increase in survival time with a partial and temporary attenuation of cachexia symptoms. These results suggest that IL-6 in OVCAR3 model may be important cachectogenic factor when centrally released by even a limited number of tumour cells.

Animals↗

PubMed2001

Erythropoietin prevents neuronal apoptosis after cerebral ischemia and metabolic stress.

Erythropoietin (EPO) promotes neuronal survival after hypoxia and other metabolic insults by largely unknown mechanisms. Apoptosis and necrosis have been proposed as mechanisms of cellular demise, and either could be the target of actions of EPO. This study evaluates whether antiapoptotic mechanisms can account for the neuroprotective actions of EPO. Systemic administration of EPO (5,000 units/kg of body weight, i.p.) after middle-cerebral artery occlusion in rats dramatically reduces the volume of infarction 24 h later, in concert with an almost complete reduction in the number of terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling of neurons within the ischemic penumbra. In both pure and mixed neuronal cultures, EPO (0.1--10 units/ml) also inhibits apoptosis induced by serum deprivation or kainic acid exposure. Protection requires pretreatment, consistent with the induction of a gene expression program, and is sustained for 3 days without the continued presence of EPO. EPO (0.3 units/ml) also protects hippocampal neurons against hypoxia-induced neuronal death through activation of extracellular signal-regulated kinases and protein kinase Akt-1/protein kinase B. The action of EPO is not limited to directly promoting cell survival, as EPO is trophic but not mitogenic in cultured neuronal cells. These data suggest that inhibition of neuronal apoptosis underlies short latency protective effects of EPO after cerebral ischemia and other brain injuries. The neurotrophic actions suggest there may be longer-latency effects as well. Evaluation of EPO, a compound established as clinically safe, as neuroprotective therapy in acute brain injury is further supported.

Animals↗

PubMed2001

Detecting chlorophyll, Secchi disk depth and surface temperature in a sub-alpine lake using Landsat imagery.

Some bio-physical parameters, such as chlorophyll a concentration, Secchi disk depth and water surface temperature were mapped in the sub-alpine Lake Iseo (Italy) using Landsat Thematic Mapper (TM) data acquired on the 7 March 1997. In order to adequately investigate the water-leaving radiance, TM data were atmospherically corrected using a partially image-based method, and the atmospheric transmittance was measured in synchrony with the satellite passage. An empirical approach of relating atmospherically corrected TM spectral reflectance values to in situ measurements, collected during the satellite data acquisition, was used. The models developed were used to map the chlorophyll concentration and Secchi disk depth throughout the lake. Both models gave high determination coefficients (R2 = 0.99 for chlorophyll and R2 = 0.85 for the Secchi disk) and the spatial distribution of chlorophyll concentration and Secchi disk depth was mapped with contour intervals of 1 mg/m3 and 1 m, respectively. A scene-independent procedure was used to derive the surface temperature of the lake from the TM data with a root mean square error of 0.3 degrees C.

Atmosphere↗

PubMed2001

Chronic elevation of plasma thioredoxin: inhibition of chemotaxis and curtailment of life expectancy in AIDS.

Thioredoxin (Trx) is an intracellular redox protein with extracellular cytokine-like and chemokine-like activities. We show here that, although plasma Trx levels are unrelated to survival of HIV-infected individuals with CD4 cell counts above 200/microl blood, survival is significantly impaired (P = 0.003) when plasma Trx is chronically elevated in HIV-infected subjects with CD4 T cell counts below this level (i.e., with Centers for Disease Control (CDC)-defined AIDS). Relevant to the mechanism potentially underlying this finding, we also present data from experimental studies in mice showing that elevated plasma Trx efficiently blocks lipopolysaccharide (LPS)-induced chemotaxis, an innate immune mechanism that is particularly crucial when adaptive immunity is compromised. Thus, we propose that elevated plasma Trx in HIV-infected individuals with low CD4 T cell counts directly impairs survival by blocking pathogen-induced chemotaxis, effectively eliminating the last (innate) barrier against establishment of opportunistic and other infections in these immunodeficient individuals.

Acetylcysteine↗

PubMed2001

Effects of epoetin alfa on the central nervous system.

Erythropoietin (EPO) is a glycoprotein that has been shown to mediate response to hypoxia, and is most notably recognized for its central role in erythropoiesis. In a series of experiments using rodent models, the ability of systemically administered recombinant human erythropoietin (r-HuEPO, epoetin alfa) to cross the blood-brain barrier and affect the outcome of neuronal injury or cognitive function was evaluated. It was shown that EPO and EPO receptors are expressed at capillaries of the brain-periphery interface, and that systemically administered epoetin alfa crossed the blood-brain barrier. Compared with control animals, epoetin alfa significantly reduced tissue damage in an ischemic stroke model when administered 24 hours before inducing stroke, with significant protection still evident when epoetin alfa was administered 6 hours poststroke. Epoetin alfa reduced injury by blunt trauma when administered 24 hours before trauma, with a significantly smaller volume of tissue necrosis noted when compared with controls. The observation that epoetin alfa may reduce nervous system inflammation was confirmed when an experimental autoimmune encephalomyelitis model in which rats were shown to have significantly delayed onset and reduced severity of experimental autoimmune encephalomyelitis symptoms after treatment with epoetin alfa. Epoetin alfa also was shown to ameliorate the latency and severity of seizures, and significantly increase survival versus controls when exposed to kainate. These findings suggest future potential therapeutic uses for epoetin alfa beyond its current use to increase erythropoiesis.

Animals↗

PubMed2001

Tumor necrosis factor and motoneuronal degeneration: an open problem.

Tumor necrosis factor (TNF) has been implicated in the pathogenesis of various central nervous system diseases with an inflammatory component. Elevated TNF levels were observed in animal models of motor neuron disease (MND), and activation of the TNF system has been reported in patients with amyotrophic lateral sclerosis (ALS). The easy availability of scientific reports to the layman through the web, often based only on the abstracts, has prompted many patients to ask whether anti-TNF therapy might be beneficial in ALS. This review discusses the possible role of TNF in motoneuronal degeneration. Although TNF is mostly regarded as neurotoxic cytokine, there are reports of a neuroprotective and neurotrophic action. Studies with animal models of ALS are not sufficient to show whether TNF has a pathogenic or a protective role in MND though anti-TNF antibodies have shown protective effects in experimental allergic encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). On the other hand, while TNF-deficient mice are protected from EAE, anti-TNF antibodies worsen the disease in MS patients, suggesting caution in extrapolating preliminary basic studies to the patient.

Animals↗

PubMed2001

Cardiac protection by pharmacological modulation of inflammation.

Inflammation is a reaction to primary injury of various kinds, such as infection and trauma, which has both beneficial and detrimental effects. Inflammation has been associated with major diseases of the heart and vessels. Research has focused not only on ischaemia but also on post-ischaemic reperfusion, which is known to activate and amplify the inflammatory response. Although reperfusion should always be attempted in the clinical environment, it has been shown experimentally that it can cause some cardiac damage, in addition to that caused by ischaemia. Therefore, it is reasonable to attempt to increase the benefit obtainable with reperfusion by modulating inflammatory processes triggered by reperfusion itself. In this field, different potential therapeutic targets have been identified and interventions have been tested over the last 30 years. With the exception of adenosine, which probably does not act merely through inhibition of the inflammatory response, no other compounds have yet proven successful in clinical trials. Active research is ongoing. Broadening the approach from the heart to the cardiovascular system, promising data is emerging on cardiovascular protection conferred by statins in patients with coronary heart disease (CHD) and high levels of C-reactive protein (CRP), a systemic marker of inflammation. Similarly, results of trials aimed at preventing cardiovascular events by eradicating chronic infections will be among the first to directly test whether such therapies will decrease risks of cardiovascular disease.

Adenosine↗

PubMed2000

Increased peripheral benzodiazepine binding sites and pentraxin 3 expression in the spinal cord during EAE: relation to inflammatory cytokines and modulation by dexamethasone and rolipram.

We have studied the mRNA expression of pentraxin 3 (PTX3) and the binding of the peripheral-type benzodiazepine receptor (PBR) ligand, [3H]-PK11195, in the spinal cord of Lewis rats where EAE was actively induced. PTX3 was induced during the active phase of EAE (day 10-14), it remained high up to 30 days and disappeared only 60 days later. Similarly, PK11195 binding peaked at day 14-17 during the recovery and it disappeared by day 60. On the other hand, the levels of TNF and IL-6 in the spinal cord were elevated at the peak and at the onset of clinical signs and returned to non-detectable by day 14-17. Dexamethasone abolished all these changes, while treatment with rolipram, delayed the appearance of the disease and then decreased its severity. However the peaks of TNF, IL-6, PBR and PTX3 levels in spinal cord were only delayed, but not reduced, by rolipram treatment. In conclusion, we show two types of inflammatory changes in EAE: acute, short term changes (TNF and IL-6), that correlate with the disease; and effects such as PTX3 expression and PK11195 binding that last longer after recovery from the disease.

Animals↗

PubMed2000

Erythropoietin crosses the blood-brain barrier to protect against experimental brain injury.

Erythropoietin (EPO), recognized for its central role in erythropoiesis, also mediates neuroprotection when the recombinant form (r-Hu-EPO) is directly injected into ischemic rodent brain. We observed abundant expression of the EPO receptor at brain capillaries, which could provide a route for circulating EPO to enter the brain. In confirmation of this hypothesis, systemic administration of r-Hu-EPO before or up to 6 h after focal brain ischemia reduced injury by approximately 50-75%. R-Hu-EPO also ameliorates the extent of concussive brain injury, the immune damage in experimental autoimmune encephalomyelitis, and the toxicity of kainate. Given r-Hu-EPO's excellent safety profile, clinical trials evaluating systemically administered r-Hu-EPO as a general neuroprotective treatment are warranted.

Animals↗

PubMed2000

PTX3, A prototypical long pentraxin, is an early indicator of acute myocardial infarction in humans.

BACKGROUND: Inflammation is an important component of ischemic heart disease. PTX3 is a long pentraxin whose expression is induced by cytokines in endothelial cells, mononuclear phagocytes, and myocardium. The possibility that PTX3 is altered in patients with acute myocardial infarction (AMI) has not yet been tested. METHODS AND RESULTS: Blood samples were collected from 37 patients admitted to the coronary care unit (CCU) with symptoms of AMI. PTX3 plasma concentrations, as measured by ELISA, higher than the mean+2 SD of age-matched controls (2.01 ng/mL) were found in 27 patients within the first 24 hours of CCU admission. PTX3 peaked at 7.5 hours after CCU admission, and mean peak concentration was 6.94+/-11.26 ng/mL. Plasma concentrations of PTX3 returned to normal in all but 3 patients at hospital discharge and were unrelated to AMI site or extent, Killip class at entry, hours from symptom onset, and thrombolysis. C-reactive protein peaked in plasma at 24 hours after CCU admission, much later than PTX3 (P<0.001). Patients >64 years old and women had significantly higher PTX3 concentrations at 24 hours (P<0.05). PTX3 was detected by immunohistochemistry in normal but not in necrotic myocytes. CONCLUSIONS: PTX3 is present in the intact myocardium, increases in the blood of patients with AMI, and disappears from damaged myocytes. We suggest that PTX3 is an early indicator of myocyte irreversible injury in ischemic cardiomyopathy.

Aged↗

PubMed2000

Inducible expression of the long pentraxin PTX3 in the central nervous system.

PTX3 is a prototypic long pentraxin consisting of a C terminal 203-amino acid pentraxin-like domain coupled with an N-terminal 178-amino acid unrelated portion. PTX3 is induced by primary proinflammatory signals in various cell types, most prominently macrophages and endothelial cells. Other long pentraxins, such as murine or rat neuronal pentraxin 1 (NP1) and human neuronal pentraxin 2 (NPTX2), are expressed in the central nervous system (CNS). The present study was designed to investigate whether PTX3 is expressed in the brain and to define the structures and cells involved. Intracerebroventricular (i.c.v.), but not i.v., injection of LPS induced high levels of PTX3 mRNA in the mouse brain. In contrast NP1 is constitutively expressed in the murine CNS and is not modulated by LPS administration. I.c.v. IL-1beta was also a potent inducer of PTX3 expression in the CNS, whereas TNFalpha was substantially less effective and IL-6 induced a barely detectable signal. Central administration of LPS and IL-1 induced PTX3 also in the periphery (heart), whereas the reverse did not occur. Expression of PTX3 was also observed in the brain of mice infected with Candida albicans (C. albicans) or Cryptococcus neoformans. (C. neoformans). The kinetics of PTX3 gene induction were consistently different between C. albicans- and C. neoformans-infected mice, according to the diverse outcome of the CNS immune reaction. In situ hybridization revealed that i.c.v. injection of LPS induced a strong PTX3 expression in presumptive glial cells, in the white matter (corpus callosum, fimbria) and meningeal pia mater as well as in dentate gyrus hilus and granule cells. No constitutive expression of PTX3 was detected. Central expression of PTX3 may amplify mechanisms of innate resistance and damage in the CNS. The possibility of a direct interaction of PTX3 with neuronal cells, as suggested for NPTX2, remains to be explored.

Animals↗

PubMed2000

Increased tumor necrosis factor and interleukin-6 production in the central nervous system of interleukin-10-deficient mice.

Interleukin-10 (IL-10) inhibits tumor necrosis factor (TNF) production. We investigated the role of endogenous IL-10 in brain TNF production. We injected IL-10-knockout mice with lipopolysaccharide (LPS,2.5 microg/mouse i.c.v.). Brain TNF and IL-6 levels were more elevated and persisted longer in IL-10-deficient mice compared with wild type mice, suggesting that IL-10 is an important negative feedback inhibitor of TNF and IL-6 production in the CNS.

Animals↗

PubMed2000

Redox regulation of chemokine receptor expression.

Cytokines and reactive oxygen intermediates (ROI) are frequent companions at sites of acute inflammation. We have shown previously that in human monocytes, bacterial lipopolysaccharide, IL-1, and tumor necrosis factor-alpha induce a rapid down-regulation of the monocyte chemotactic protein-1 receptor CCR2 (CC chemokine receptor-2). These stimuli also induce production of ROI. In this paper, we investigate the influence of antioxidants and/or ROI on chemokine-receptor expression. In human monocytes, the antioxidant pyrrolidine dithiocarbamate (PDTC) rapidly inhibited CCR2 (95-100% of inhibition) and CCR5 (77-100% of inhibition) mRNA expression by strongly decreasing transcript stability. CCR2 half-life was decreased from 1.5 h to 45 min; CCR5 half-life was decreased from 2 h to 70 min. This inhibitory activity also included CXCR4 (CXC chemokine receptor-4) but not CXCR2 receptor and, although to a lesser extent, was shared by the antioxidants N-acetyl-l-cysteine and 2-mercaptoethanol. In contrast, the ROI-generating system xanthine/xanthine oxidase increased CCR5 and CXCR4 mRNA expression and counteracted the inhibitory effect of PDTC. Accordingly, H(2)O(2) and the glutathione-depleting drug buthionine sulfoximine increased to different extents CCR2, CCR5, and CXCR4 mRNA expression. The PDTC-mediated inhibition of CCR5 and CXCR4 mRNA expression was associated with decreased chemotactic responsiveness (>90% inhibition) and with a marked inhibition of surface-receptor expression. In contrast, xanthine/xanthine oxidase opposed the bacterial lipopolysaccharide- and tumor necrosis factor-alpha-mediated inhibition of CCR5 and CXCR4 mRNA expression and increased both the CCR5 surface expression and the cell migration (3-fold) in response to macrophage inflammatory protein-1beta. These results suggest that the redox status of cells is a crucial determinant in the regulation of the chemokine system.

Acetylcysteine↗

PubMed2000

Proteins of rat serum V: adjuvant arthritis and its modulation by nonsteroidal anti-inflammatory drugs.

The effect of adjuvant arthritis (AA) on the pattern of rat serum proteins includes the upregulation of haptoglobin, orosomucoid, alpha2-macroglobulin, serine protease inhibitor-3, thiostatin, alpha1-antitrypsin, C-reactive protein, and the downregulation of kallikrein-binding protein, alpha1-inhibitor III, apolipoprotein A-I, alpha2-HS-glycoprotein, albumin, apolipoprotein A-IV, transthyretin and transferrin. Minor changes (+/- 20%) are observed for Gc-globulin, ceruloplasmin, and alpha1-macroglobulin. AA thus grossly resembles the acute inflammatory response elicited by the injection of turpentine, although the changes in the levels of negative acute-phase proteins (APP) are smaller in acute inflammation. Indomethacine and ibuprofen inhibit the effects of arthritis on the synthesis of rat serum proteins in different ways: The former is, on average, three times as effective as the latter. Each drug interferes differently with different proteins. In animals without AA, both nonsteroidal anti-inflammatory drugs (NSAID) mimic the inflammatory pattern to a certain extent, with more effect on the negative than on the positive APPs. Overall, the shifts in serum protein levels parallel changes in inflammatory parameters such as joint swelling and serum interleukin-6 (IL-6) activity. Protein quantitation after two-dimensional electrophoresis (2-DE) reveals some effects of the drugs per se which escape detection by other routine tests.

Animals↗

PubMed2000

Lps induces IL-6 in the brain and in serum largely through TNF production.

We investigated the relative contribution of IL-6 and PGE2 directly induced by LPS and indirectly induced via TNF, using in vivo and in vitro models in the mouse. In these models we have used as tools an anti-TNF antibody and a cyclooxygenase inhibitor, the S enantiomer of ketoprofen (S-KPF). Anti-TNF antibodies inhibited LPS-induced IL-6 production in three different models: IL-6 production by mouse peritoneal macrophages in vitro; serum IL-6 levels induced by intraperitoneal LPS; and brain IL-6 levels induced by an intracerebroventricular injection of LPS. However, in vitro anti-TNF antibodies, did not inhibit LPS-induced PGE2, indicating that this effect is not mediated by TNF. Since PGE2 has an opposite effect on TNF and IL-6 production, inhibiting that of TNF but inducing that of IL-6, we investigated the effect of S-KPF on TNF and IL-6 production in vivo following LPS injection. Both TNF and IL-6 induction was augmented by S-KPF, but anti-TNF antibodies abolished the augmentation of IL-6 production. Thus, the effect of anti-inflammatory drugs on IL-6 production in some models can be secondary to their effect on TNF production.

Animals↗

PubMed2000

Decrease in brain cytochrome P450 enzyme activities during infection and inflammation of the central nervous system.

The effect of infection and inflammation of the central nervous system (CNS) on cytochrome-P450-dependent activities in brain, spinal cord and liver microsomes was determined. For this, two models were used: (1) the intracerebroventricularly injected lipopolysaccharide (LPS) model and (2) the experimental auto-immune encephalomyelitis (EAE) model. In the LPS model, aminopyrine N-demethylase (AMND) and ethoxycoumarin O-deethylase (ECOD) activities (both P450 dependent) were significantly decreased (35 and 20%, respectively) in brain microsomes. In the EAE model, only ECOD activity was significantly lower (18%). In the liver, a decrease in total P450, AMND and ECOD activities was only observed in the LPS model. In both models, tumour necrosis factor (TNF) was significantly elevated in brain and spinal cord tissues. In serum, TNF was only detectable in the LPS model. It is concluded that an infection or inflammation located in the CNS, which is accompanied by high TNF levels, results in a decrease in P450-dependent metabolism not only in the liver but in the brain as well.

7-Alkoxycoumarin O-Dealkylase↗

PubMed2000

Neurosteroid levels are increased in vivo after LPS treatment and negatively regulate LPS-induced TNF production.

Neuroactive steroids such as dehydroepiandrosterone sulfate and pregnenolone inhibit lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) production. Corticosteroids not only inhibit TNF production but their levels are increased in vivo after endotoxin injection, thus representing a feedback system that limits TNF production. We wondered whether the same could be true for neuroactive steroids. Thus, the possibility that neuroactive steroids might be increased concomitantly to TNF induction in vivo in mice treated with LPS was investigated. Increased plasma and hippocampal levels of allopregnanolone (but not of dehydroepiandrosterone or pregnenolone) were found 90 min after LPS injection. Allopregnanolone and progesterone (IC50 10- 7 and 10- 9 M, respectively) also inhibited TNF production by mouse peritoneal macrophages in vitro at concentrations in the range of those detected in vivo. These findings suggest that neuroactive steroids may act as endogenous inhibitors of cerebral and systemic TNF production.

Animals↗

PubMed1999

Thioredoxin, a redox enzyme released in infection and inflammation, is a unique chemoattractant for neutrophils, monocytes, and T cells.

Thioredoxin (Trx) is a ubiquitous intracellular protein disulfide oxidoreductase with a CXXC active site that can be released by various cell types upon activation. We show here that Trx is chemotactic for monocytes, polymorphonuclear leukocytes, and T lymphocytes, both in vitro in the standard micro Boyden chamber migration assay and in vivo in the mouse air pouch model. The potency of the chemotactic action of Trx for all leukocyte populations is in the nanomolar range, comparable with that of known chemokines. However, Trx does not increase intracellular Ca2+ and its activity is not inhibited by pertussis toxin. Thus, the chemotactic action of Trx differs from that of known chemokines in that it is G protein independent. Mutation of the active site cysteines resulted in loss of chemotactic activity, suggesting that the latter is mediated by the enzyme activity of Trx. Trx also accounted for part of the chemotactic activity released by human T lymphotropic virus (HTLV)-1-infected cells, which was inhibited by incubation with anti-Trx antibody. Since Trx production is induced by oxidants, it represents a link between oxidative stress and inflammation that is of particular interest because circulating Trx levels are elevated in inflammatory diseases and HIV infection.

Animals↗