Biomedical subjects

Lucas Liaudet

Publications and source records attributed to Lucas Liaudet.

53 records · Page 3Linked to original sources

PubMed2003

Endothelium-dependent vasodilation in the skin microcirculation of patients with septic shock.

The evidence for endothelial dysfunction in sepsis is mostly restricted to animal models. We investigated endothelial function in the skin microcirculation of eight patients hospitalized for septic shock in an intensive care unit (ICU). All patients required adrenergic support. Twelve hemodynamically stable ICU patients without sepsis who did not receive any vasoactive medication were used as controls. The two groups were of similar age and sex ratio. For additional reference, 16 healthy, nonsmoking subjects matched for age and sex to the first two groups were also studied. The evaluation of endothelial function was based on the comparison of skin blood flow responses to iontophoretically applied acetylcholine (Ach, an endothelium-dependent vasodilator) and sodium nitroprusside (SNP, an endothelium-independent vasodilator). Skin blood flow was measured on the volar face of the forearm using laser Doppler imaging. Before application of Ach or SNP, the mean baseline skin blood flow was below 100 perfusion units (PU) in all subjects and did not differ between groups. The maximal increase in blood flow elicited by both agents was significantly depressed in the patients with sepsis (Ach: 167 +/- 63 PU; SNP: 138 +/- 34 PU, mean +/- SD) compared with the ICU control patients (Ach: 291 +/- 135 PU, P < 0.05; SNP: 261 +/- 121 PU, P < 0.01) and the healthy, nonsmoking groups (Ach: 336 +/- 98 PU, P < 0.01; SNP: 304 +/- 81 PU, P < 0.01). The ratio of responses to Ach and SNP did not significantly differ between groups (septic: 1.22 +/- 0.40; ICU control 1.18 +/- 0.46, healthy, nonsmoking 1.12 +/- 0.24, P = 0.86). Thus, sepsis was not associated with a selective depression of the endothelium-dependent response. These results suggest that the capacity of the endothelium to produce signals for vasorelaxation remains intact in the skin microcirculation of patients with septic shock.

Acetylcholine↗

PubMed2003

Role of poly(adenosine diphosphate-ribose) polymerase 1 in septic peritonitis.

Peritonitis generally results from gastrointestinal perforation, with systemic sepsis developing over hours or days from an initially localized nidus of infection. The consecutive inflammatory response induces the widespread generation of oxidants and free radicals, which are potent inducers of breaks and nicks in double-stranded DNA. This genetic damage triggers the activation of the nuclear enzyme poly(ADP-ribose) polymerase 1, which, in turn, cleaves the respiratory coenzyme nicotinamide adenine dinucleotide into nicotinamide and ADP ribose. The consecutive decrease in cellular nicotinamide adenine dinucleotide inhibits glycolysis and mitochondrial respiration, leading to cellular energy collapse and necrotic cell death. In parallel, poly(ADP-ribose) polymerase 1 positively regulates inflammatory signal transduction pathways through a functional association with the transcription factor nuclear factor kappaB, resulting in a progressive amplification of local inflammation. Recent data indicate that these molecular mechanisms are instrumental in the development of cardiovascular collapse and multiple organ dysfunction in sepsis, supporting the view that pharmacologic inhibitors of poly(ADP-ribose) polymerase 1 may represent useful tools for the treatment of this condition.

Animals↗

PubMed2003

Relapsing acute respiratory failure induced by minocycline.

The antibiotic minocycline, which is used in the treatment of acne, has been associated with various pulmonary complications such as pulmonary lupus and hypersensitivity pneumonitis. We now report a particularly severe case of minocycline-related pulmonary toxicity that was characterized by a relapsing form of hypersensitivity eosinophilic pneumonia complicated by acute respiratory failure.

Acne Vulgaris↗

PubMed2002

Role of poly(ADP-ribose) polymerase activation in endotoxin-induced cardiac collapse in rodents.

Reactive oxygen and nitrogen species are overproduced in the cardiovascular system during circulatory shock. Oxidant-induced cell injury involves the activation of poly(ADP-ribose) polymerase (PARP). Using a dual approach of PARP-1 suppression, by genetic deletion or pharmacological inhibition with the new potent phenanthridinone PARP inhibitor PJ34 [the hydrochloride salt of N-(oxo-5,6-dihydro-phenanthridin-2-yl)-N,N-dimethylacetamide], we studied whether the impaired cardiac function in endotoxic shock is dependent upon the PARP pathway. Escherichia coli endotoxin (lipopolysaccharide, LPS) at 55 mg/kg, i.p., induced a severe depression of the systolic and diastolic contractile function, tachycardia, and a reduction in mean arterial blood pressure in both rats and mice. Treatment with PJ34 significantly improved cardiac function and increased the survival of rodents. In addition, LPS-induced depression of left ventricular performance was significantly less pronounced in PARP-1 knockout mice (PARP(-/-)) as compared with their wild-type littermates (PARP(+/+)). Thus, PARP activation in the cardiovascular system is an important contributory factor to the cardiac collapse and death associated with endotoxin shock.

Animals↗

PubMed2002

Pharmacologic inhibition of poly(adenosine diphosphate-ribose) polymerase may represent a novel therapeutic approach in chronic heart failure.

OBJECTIVES: We investigated the effects of a novel ultrapotent poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor, PJ34, on cardiac and endothelial dysfunction in a rat model of chronic heart failure (CHF). BACKGROUND: Overactivation of the nuclear enzyme PARP importantly contributes to the development of cell dysfunction and tissue injury in various pathophysiologic conditions associated with oxidative stress, including myocardial reperfusion injury, heart transplantation, stroke, shock, and diabetes. METHODS: Chronic heart failure was induced in Wistar rats by chronic ligation of the left anterior descending coronary artery. Left ventricular (LV) function and ex vivo vascular contractility and relaxation were measured 10 weeks after the surgery. Nitrotyrosine (NT) formation and PARP activation were detected by immunohistochemistry. RESULTS: Chronic heart failure induced increased NT formation and PARP activation in the myocardium and intramural vasculature, depressed LV performance, and impaired vascular relaxation of aortic rings. PJ34 significantly decreased myocardial PARP activation but not NT formation, and improved both cardiac dysfunction and vascular relaxation. CONCLUSIONS: Poly(ADP-ribose) polymerase inhibition represents a novel approach for the experimental treatment of CHF.

Animals↗

PubMed2002

Activation of poly(ADP-Ribose) polymerase-1 is a central mechanism of lipopolysaccharide-induced acute lung inflammation.

Recent studies demonstrated that activation of the nuclear enzyme poly(ADP-ribose) polymerase-1 (PARP-1) by oxidant-mediated DNA damage is an important pathway of tissue injury in conditions associated with oxidative stress. Using a dual approach of PARP-1 suppression, by genetic deletion or pharmacological inhibition with the phenanthridinone PARP inhibitor PJ-34, we now demonstrate an essential role of PARP-1 in the development of pulmonary inflammation induced by lipopolysaccharide (LPS). PARP-1+/+ and PARP-1-/- mice received an intratracheal instillation of LPS (50 microg), followed after 24 h by bronchoalveolar lavage to measure the cytokines TNF-alpha, IL-1beta, and IL-6, the chemokines MIP-1alpha and MIP-2, leukocyte counts and myeloperoxidase activity (neutrophil accumulation), protein content (high permeability edema), and nitrite/ nitrate (nitric oxide production). Malondialdehyde (an index of lipid peroxidation) was measured in lung tissue. Similar experiments were conducted in BALB/c mice treated with PJ-34 or vehicle. The absence of functional PARP-1 reduced LPS-induced increases of cytokines and chemokines, alveolar neutrophil accumulation, lung hyperpermeability, NO production, and lipid peroxidation. Histological analysis revealed attenuated lung damage after PARP inhibition. Our findings support a mechanistic role of PARP-1 in the regulation of LPS-induced lung inflammation. Pharmacological inhibition of PARP may be useful in clinical conditions associated with overwhelming lung inflammation.

Animals↗

PubMed2002

Poly(ADP-Ribose) polymerase inhibition reduces reperfusion injury after heart transplantation.

The aim of the present study was to investigate the effects of the novel poly(ADP-ribose) polymerase (PARP) inhibitor PJ34 (N-(6-oxo-5,6-dihydro-phenanthridin-2-yl)-N,N-dimethylacetamide) on myocardial and endothelial function after hypothermic ischemia and reperfusion in a heterotopic rat heart transplantation model. After a 1-hour ischemic preservation, reperfusion was started either after application of placebo or PJ34 (3 mg/kg). The assessment of left ventricular pressure-volume relations, total coronary blood flow, endothelial function, myocardial high energy phosphates, and histological analysis were performed at 1 and 24 hours of reperfusion. After 1 hour, myocardial contractility and relaxation, coronary blood flow, and endothelial function were significantly improved and myocardial high energy phosphate content was preserved in the PJ34-treated animals. Improved transplant function was also seen with treatment with another, structurally different PARP inhibitor, 5-aminoisoquinoline. The PARP inhibitors did not affect baseline cardiac function. Immunohistological staining confirmed that PJ34 prevented the activation of PARP in the transplanted hearts. The activation of P-selectin and ICAM-1 was significantly elevated in the vehicle-treated heart transplantation group. Thus, pharmacological PARP inhibition reduces reperfusion injury after heart transplantation due to prevention of energy depletion and downregulation of adhesion molecules and exerts a beneficial effect against reperfusion-induced graft coronary endothelial dysfunction.

Adenosine Diphosphate↗

PubMed2002

Endothelial dysfunction in aging animals: the role of poly(ADP-ribose) polymerase activation.

Recent work has demonstrated the production of reactive oxygen and nitrogen species in the vasculature of aging animals. Oxidant induced cell injury triggers the activation of nuclear enzyme poly(ADP ribose) polymerase (PARP) leading to endothelial dysfunction in various pathophysiological conditions (reperfusion, shock, diabetes). Here we studied whether the loss of endothelial function in aging rats is dependent upon the PARP pathway within the vasculature. Young (3 months-old) and aging (22 months-old) Wistar rats were treated for 2 months with vehicle or the PARP inhibitor PJ34. In the vehicle-treated aging animals there was a significant loss of endothelial function, as measured by the relaxant responsiveness of vascular rings to acetylcholine. Treatment with PJ34, a potent PARP inhibitor, restored normal endothelial function. There was no impairment of the contractile function and endothelium-independent vasodilatation in aging rats. Furthermore, we found no deterioration in the myocardial contractile function in aging animals. Thus, intraendothelial PARP activation may contribute to endothelial dysfunction associated with aging.

Aging↗

PubMed2002

Inosine exerts a broad range of antiinflammatory effects in a murine model of acute lung injury.

OBJECTIVE: To investigate the effects of inosine on the acute lung inflammation induced by lipopolysaccharide (LPS) in vivo and on the activation and cytotoxicity elicited by proinflammatory cytokines on human lung epithelial (A549) cells in vitro. SUMMARY BACKGROUND DATA: Inosine is an endogenous purine recently shown to exert immunomodulatory and antiinflammatory effects. METHODS: Mice challenged with intratracheal LPS (50 microg) were treated after 1, 6, and 12 hours with inosine (200 mg/kg intraperitoneal) or vehicle. After 24 hours, bronchoalveolar lavage fluid was obtained to measure proinflammatory (tumor necrosis factor-alpha [TNF-alpha], interleukin [IL]-1beta, IL-6), and antiinflammatory (IL-10, IL-4) cytokines, chemokines (MIP-1alpha and MIP-2), myeloperoxidase activity and total cell counts, nitric oxide production, and proteins. Lung histology and immunohistochemical detection of 3-nitrotyrosine, a marker of nitrosative stress, were performed in inflated-fixed lungs. In vitro, cell viability and production of the chemokine IL-8 were evaluated in A549 cells stimulated with a mixture of cytokines in the presence or absence of inosine. RESULTS: Inosine downregulated the LPS-induced expression of TNF-alpha, IL-1beta, IL-6 and MIP-2 and tended to reduce MIP-1alpha, whereas it enhanced the production of IL-4. Total leukocyte counts, myeloperoxidase, nitric oxide production, and proteins were all significantly decreased by inosine. The purine also improved lung morphology and suppressed 3-nitrotyrosine staining in the lungs after LPS. Inosine attenuated the cytotoxicity and the expression of IL-8 induced by proinflammatory cytokines in A549 cells. CONCLUSIONS: Inosine largely suppressed LPS-induced lung inflammation in vivo and reduced the toxicity of cytokines in lung cells in vitro. These data support the proposal that inosine might represent a useful adjunct in the therapy of acute respiratory distress syndrome.

Animals↗

PubMed2002

Novel phenanthridinone inhibitors of poly (adenosine 5'-diphosphate-ribose) synthetase: potent cytoprotective and antishock agents.

OBJECTIVE: To synthesize novel inhibitors of the nuclear enzyme poly(adenosine 5'-diphosphate [ADP]-ribose) synthetase (PARS), also known as poly(ADP-ribose) polymerase (PARP), and to test them in in vitro models of oxidant-induced cytotoxicity and in endotoxin and splanchnic occlusion-reperfusion-induced shock. DESIGN: Randomized, prospective laboratory study. SETTING: Research laboratory. SUBJECTS: Murine macrophages, thymocytes, and endothelial cells; Balb/c mice and Wistar rats. INTERVENTIONS: Macrophages and endothelial cells were treated with peroxynitrite and bleomycin to induce PARS activation, and thymocytes were treated with peroxynitrite to induce cell necrosis. Novel PARS inhibitors were synthesized and used to reduce PARS activation and to reverse cytotoxicity. Balb/c mice were subjected to splanchnic occlusion and reperfusion and were pretreated with various doses (1-10 mg/kg intraperitoneally) of PJ34, a selected, potent, water-soluble PARS inhibitor. The passage of fluorescein isothiocyanate-conjugated dextran (4 kDa) was analyzed in everted gut ileal sacs incubated ex vivo as an index of gut permeability. Wistar rats were subjected to Escherichia coli bacterial lipopolysaccharide (40 mg/kg intraperitoneally). PJ34 was also used at 10 mg/kg intraperitoneally, 1 hr before lipopolysaccharide or at 25 mg/kg intraperitoneally 1 hr after lipopolysaccharide treatment. Serum concentrations of indicators or multiple organ injury, concentrations of various proinflammatory mediators, and tissue concentrations of myeloperoxidase and malondialdehyde were measured. In addition, survival rates and vascular contractile and relaxant responses were recorded. MEASUREMENTS AND MAIN RESULTS: Appropriate modifications of the phenanthridinone core structure yielded significant increases in the potency of the compounds, both as PARS inhibitors and as cytoprotective agents. The compound N-(6-oxo-5,6-dihydro-phenanthridin-2-yl) -N,N-dimethylacetamide (designated as PJ34) was one of the potent PARS inhibitors of the series, and it dose-dependently protected against thymocyte necrosis, with a half-maximal restoration of cell viability of 35 nM and complete protection at 200 nM. PARS activation also was visualized by immunohistochemistry and was dose-dependently suppressed by PJ34. The effect of PJ34 was dose-dependently reversed by excess nicotinamide adenine dinucleotide (oxidized). The PARS inhibitors dose-dependently suppressed proinflammatory cytokine and chemokine production and restored viability in immunostimulated macrophages. PJ34 was selected for the subsequent in vivo studies. PJ34 significantly protected against splanchnic reperfusion-induced intestinal hyperpermeability in the mouse. PJ34 reduced peak plasma concentrations of tumor necrosis factor-alpha, interleukin-1beta, and nitrite/nitrate in the plasma of lipopolysaccharide-treated rats. PJ34 ameliorated the lipopolysaccharide-induced increases in indexes of liver and kidney failure and concentrations of myeloperoxidase and malondialdehyde in the lung and gut. Lipopolysaccharide elicited vascular dysfunction, which was normalized by PJ34. Lipopolysaccharide-induced mortality was reduced by PJ34 (both pre- and posttreatment). CONCLUSIONS: The novel series of phenanthridinone PARS inhibitors have potent cytoprotective effects in vitro and significant protective effects in shock and reperfusion injury in rodent models in vivo.

Animals↗

PubMed2002

Resistance to acute septic peritonitis in poly(ADP-ribose) polymerase-1-deficient mice.

Sepsis is associated with a widespread production of proinflammatory cytokines and various oxidant species. Activation of the enzyme poly(ADP-ribose) polymerase (PARP) has been shown to contribute to cell necrosis and organ failure in various diseases associated with inflammation and reperfusion injury. The aim of the current study was to elucidate the role of PARP activation in the multiple organ dysfunction complicating sepsis in a murine model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). Mice genetically deficient in PARP (PARP-/-) and their wild-type littermates (PARP+/+) were subjected to CLP. After 12 and 24 h, the proinflammatory cytokines TNF-alpha and IL-6, as well as the anti-inflammatory cytokine IL-10, and nitrite/nitrate were measured in plasma samples. Organs were harvested for the measurement of myeloperoxidase (MPO) and malondialdehyde (MDA) levels, and immunohistochemical staining for nitrotyrosine and poly(ADP ribose) was performed in gut sections. PARP-/- mice, and their wild-type littermate showed a similar time-dependent increase in plasma nitrite/nitrate and in gut and lung MDA content, as well as the presence of nitrotyrosine in the gut. In contrast to wild-type mice showing a PARP activation in the gut, PARP-/- mice had no staining for poly(ADP ribose). PARP-/- mice had significantly lower plasma levels of TNF-alpha, IL-6, and IL-10, and they exhibited a reduced degree of organ inflammation, indicated by decreased MPO activity in the gut and lung. These effects were associated with a significant improvement in the survival of CLP in PARP-/- mice. Thus, PARP activation has an important role in systemic inflammation and organ damage in the present model of polymicrobial septic shock.

Acute Disease↗

PubMed2002

Poly(adenosine 5'-diphosphate) ribose polymerase activation as a cause of metabolic dysfunction in critical illness.

Poly(adenosine 5'-diphosphate) ribose polymerase is a nuclear enzyme activated in response to genotoxic stress induced by a variety of DNA damaging agents. Several oxygen and nitrogen-centered free radicals, notably peroxynitrite, are strong inducers of DNA damage and poly(adenosine 5'-diphosphate) ribose polymerase activation in vitro and in vivo. Activation of this nuclear enzyme depletes the intracellular stores of its substrate nicotinamide adenine dinucleotide, slowing the rate of glycolysis, mitochondrial electron transport and adenosine triphosphate formation. This process triggers a severe energetic crisis within the cell, leading to acute cell dysfunction and cell necrosis. Poly(adenosine 5'-diphosphate) ribose polymerase also plays an important role in the regulation of inflammatory cascades, through a functional association with various transcription factors and transcription co-activators. Recent works identified this enzyme as a critical mediator of cellular metabolic dysfunction, inflammatory injury, and organ damage in conditions associated with overwhelming oxidative stress, including systemic inflammation, circulatory shock, and ischemia-reperfusion. Accordingly, pharmacological inhibitors of poly(adenosine 5'-diphosphate) ribose polymerase protect against cell death and tissue injury in such conditions, and may therefore represent novel therapeutic tools to limit multiple organ damage and dysfunction in critically ill patients.

Critical Illness↗

PubMed2002

Comparison of inflammation, organ damage, and oxidant stress induced by Salmonella enterica serovar Muenchen flagellin and serovar Enteritidis lipopolysaccharide.

Gram-negative sepsis is related to the activation of interconnected inflammatory cascades in response to bacteria and their products. Recent work showed that flagellin, the monomeric subunit of bacterial flagella, triggers innate immune responses mediated by Toll-like receptor 5. Here, we compared the effects of Salmonella enterica serovar Enteritidis lipopolysaccharide (LPS) and recombinant Salmonella enterica serovar Muenchen flagellin administered intravenously (100 microg) to mice. Flagellin and LPS both elicited a prototypical systemic inflammatory response, with increased levels of tumor necrosis factor alpha, gamma interferon, interleukin 6 and 10, and nitrate in plasma. Flagellin induced a widespread oxidative stress, evidenced by an increase in malondialdehyde and a decrease in reduced glutathione in most organs, as well as liver (increased plasma aminotransferases), but not renal, injury. Alternatively, LPS resulted in a less severe oxidative stress and triggered renal, but not liver, damage. Sequestration of polymorphonuclear neutrophils (increased myeloperoxidase activity) in the lungs was observed with both toxins, while only LPS recruited neutrophils in the gut. In additional experiments, the simultaneous administration of small doses of LPS and flagellin (10 microg) induced a synergistic enhancement of the production of proinflammatory cytokines. Our data support a novel concept implicating flagellin as a mediator of systemic inflammation, oxidant stress, and organ damage induced by gram-negative bacteria.

Alanine Transaminase↗

PubMed2002

The Flagellin-TLR5 Axis: Therapeutic Opportunities.

Motile bacteria synthesize large-sized surface structures known as flagella through the ordered polymerization of protein subunits. Flagellin, a protein of 40-60 kDa, is the principal constituent of the flagellum; each flagellum consists of approximately 20,000 flagellin molecules. An alignment of the amino acid sequences from different Gram-negative species shows a high degree of similarity in the amino and carboxy terminal domains. In contrast, the central hypervariable regions of these proteins are quite divergent. Recent work reveals that--in addition to playing a role in bacterial adhesion--monomeric flagellin, a protein component of flagellated bacteria, can also act as a soluble immunostimulatory and proinflammatory factor, activating the immune/inflammatory axis via the Toll-like receptor 5-nuclear factor-kappaB axis. Monocytes and macrophages, as well as intestinal and pulmonary epithelial cells, respond to monomeric flagellin at low concentrations. Administration of flagellin at doses comparable to or lower than that of bacterial lipopolysaccharide (endotoxin) can induce prominent local and systemic immune/inflammatory responses in vivo. Recognition of the flagellin-TLR5 pathway offers novel opportunities for the experimental therapy of various forms of shock, sepsis, acute respiratory distress syndrome, bacterial inflammation and infection. (c) Prous Science 2002. All rights reserved.

Journal Article↗

PubMed2002

The role of poly(ADP-ribose) polymerase activation in the development of myocardial and endothelial dysfunction in diabetes.

Patients with diabetes exhibit a high incidence of diabetic cardiomyopathy and vascular complications, which underlie the development of retinopathy, nephropathy, and neuropathy and increase the risk of hypertension, stroke, and myocardial infarction. There is emerging evidence that the activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) importantly contributes to the development of endothelial dysfunction in a streptozotocin-induced model of diabetes. We investigated the role of PARP activation in the pathogenesis of cardiac dysfunction in streptozotocin-induced and genetic (nonobese diabetic) models of diabetes in rats and mice. Development of diabetes was accompanied by hyperglycemia, cardiac PARP activation, a selective loss of endothelium-dependent vasodilation in the thoracic aorta, and an early diastolic dysfunction of the heart. Treatment with a novel potent phenanthridinone-based PARP inhibitor, PJ34, starting 1 week after the onset of diabetes, restored normal vascular responsiveness and significantly improved cardiac dysfunction, despite the persistence of severe hyperglycemia. The beneficial effect of PARP inhibition persisted even after several weeks of discontinuation of the treatment. Thus, PARP activation plays a central role in the pathogenesis of diabetic cardiovascular (cardiac as well as endothelial) dysfunction. PARP inhibitors may exert beneficial effects against the development of cardiovascular complications in diabetes.

Animals↗

PubMed2002

Activation of poly(ADP-ribose) polymerase contributes to the endothelial dysfunction associated with hypertension and aging.

Increased production of reactive oxygen and nitrogen species has recently been implicated in the pathogenesis of endothelial dysfunction associated with atherosclerosis, hypertension and aging. Oxidant induced cell injury triggers the activation of nuclear enzyme poly(ADP-ribose) polymerase (PARP), which in turn contributes to cardiac and vascular dysfunction in various pathophysiological conditions including diabetes, reperfusion injury and circulatory shock. Here we investigated the role of PARP activation in the pathogenesis of cardiac and endothelial dysfunction associated with atherosclerosis, hypertension and aging. Retired breeder spontaneously hypertensive rats (SHR, 40 weeks old) and apolipoprotein E knockout mice (apoE-Ko, 10 weeks old) were treated for 20 weeks with vehicle or the potent PARP inhibitor PJ34. In the vehicle-treated SHR rats and apoE-Ko mice (kept on atherogenic diet) there was a significant loss of endothelial function, as measured by the relaxant responsiveness of vascular rings to acetylcholine. SHR rats also developed severe hypertension and cardiac hypertrophy. Treatment with the PARP inhibitor did not influence high blood pressure and cardiac hypertrophy in SHR rats, but it improved Ach-induced, NO-mediated vascular relaxation. In addition to the beneficial effects of chronic treatment with PARP inhibitor, 1-h in vitro incubation of aortic rings from SHR rats with PJ34 (3 micromol/l) was also able to improve the endothelial dysfunction. In contrast, in apoE-Ko mice PJ34 treatment did not affect the parameters studied. Thus, PARP activation contributes to the pathogenesis of endothelial dysfunction associated with hypertension and aging, but not in the current experimental model of atherosclerosis.

Acetylcholine↗

PubMed2002

Part II: beneficial effects of the peroxynitrite decomposition catalyst FP15 in murine models of arthritis and colitis.

BACKGROUND: Peroxynitrite is a reactive oxidant species produced from nitric oxide and superoxide, which has been indirectly implicated in the pathogenesis of many inflammatory conditions including arthritis and colitis. Here, using a novel peroxynitrite decomposition catalyst, FP15, we directly investigate the role of peroxynitrite in the pathogenesis of arthritis and colitis in rodent models. METHODS: Arthritis was induced in mice by intradermal collagen injection; incidence and severity of arthritis was monitored using a macroscopic scoring system. At the end of the experiment paws were taken for determination of neutrophil infiltration (myeloperoxidase [MPO] activity), oxidative stress (malondialdehyde [MDA] level), and cytokine/chemokine levels. Colitis was induced in mice by 5% dextran sodium sulfate (DSS) in their drinking water. Colitis symptoms were assessed 10 days later, the parameters determined included body weight, rectal bleeding, colon length, colonic MPO and MDA levels, and colon histologic damage. RESULTS: Treatment with FP15 significantly reduced the inflammation and oxidative stress in arthritis and colitis. FP15 reduced both the incidence and severity of arthritis in mice and this was associated with reduced paw MPO and MDA levels. Similarly, in colitis, FP15 reduced colon damage, and this was associated with reduced colon neutrophil infiltration and oxidative stress. CONCLUSIONS: The protective effect of FP15 suggests that peroxynitrite plays a significant pathogenetic role in arthritis and colitis in the currently employed rodent models. Further work is needed to determine whether neutralization of peroxynitrite also represents a promising strategy to treat human inflammatory diseases such as arthritis and colitis.

Administration, Oral↗