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PubMed2005

Low UVA doses activate the transcription factor NFAT in human fibroblasts by a calcium-calcineurin pathway.

UVA radiation induces an inflammatory response as observed in erythema, and the cytokine genes involved in this response are under the control of the transcription factor NFAT (nuclear factor of activated T lymphocytes). The effects of UVA on NFAT DNA binding activity were investigated in cultured human fibroblasts. A dose-dependent increase was observed within the range of 0.6-4.5 J/cm2 UVA. Beyond this value, the activity decreased and a value of 60% of control was found at 13.5 J/cm2. The enhancement of NFAT activity was transient and peaked 45 min after irradiation. Furthermore, immunoblot analysis demonstrated a nuclear translocation of NFAT under low UVA doses. Concomitantly, as assessed by the fluorescent probe Fluo3, UVA induced an increase in intracellular free calcium, with a maximum increase found at 9 J/cm2. The UVA-induced activation of NFAT was prevented by the intracellular calcium trapping drug BAPTA, whereas the extracellular calcium chelator EGTA had no significant effect. In addition, the calcineurin inhibitors cyclosporin A and FK506 both prevented the UVA-induced NFAT activation. Furthermore, the antioxidant vitamin E prevented the UVA-induced increase in both intracellular free calcium and NFAT binding activity. Finally, the cytotoxicity of UVA was enhanced in the presence of the inhibitors cyclosporin and FK506, suggesting that the activation of NFAT might play a protective role after the UVA-induced oxidative stress. These results demonstrate that UVA activates the calcium-calcineurin signaling pathway of NFAT activation, that the calcium ions are mainly released from intracellular stores, and that the increase in calcium is, at least partially, due to the oxidative stress generated under UVA. Because NFAT regulates several genes implicated in the inflammatory response, the enhancement of NFAT activity by low UVA doses might be interpreted in view of the proinflammatory action of solar radiation.

Antioxidants↗
PubMed2002

Non-cholinergic strategies for treating and preventing Alzheimer's disease.

The pathophysiology of Alzheimer's disease is complex and involves several different biochemical pathways. These include defective beta-amyloid (Abeta) protein metabolism, abnormalities of glutamatergic, adrenergic, serotonergic and dopaminergic neurotransmission, and the potential involvement of inflammatory, oxidative and hormonal pathways. Consequently, these pathways are all potential targets for Alzheimer's disease treatment and prevention strategies. Currently, the mainstay treatments for Alzheimer's disease are the cholinesterase inhibitors, which increase the availability of acetylcholine at cholinergic synapses. Since the cholinesterase inhibitors confer only modest benefits, additional non-cholinergic Alzheimer's disease therapies are urgently needed. Several non-cholinergic agents are currently under development for the treatment and/or prevention of Alzheimer's disease. These include anti-amyloid strategies (e.g. immunisation, aggregation inhibitors, secretase inhibitors), transition metal chelators (e.g. clioquinol), growth factors, hormones (e.g. estradiol), herbs (e.g. Ginkgo biloba), nonsteroidal anti-inflammatory drugs (NSAIDs, e.g. indomethacin), antioxidants, lipid-lowering agents, antihypertensives, selective phosphodiesterase inhibitors, vitamins (E, B12, B6, folic acid) and agents that target neurotransmitter or neuropeptide alterations. Neurotransmitter receptor-based approaches include agents that modulate certain receptors (e.g. nicotinic, muscarinic, alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid [AMPA], gamma-aminobutyric acid [GABA], N-methyl-D-aspartate [NMDA]) and agents that increase the availability of neurotransmitters (e.g. noradrenergic reuptake inhibitors). Of these strategies, the NMDA receptor antagonist memantine is in the most advanced stage of development in the US and is already approved in Europe as the first treatment for moderately severe to severe Alzheimer's disease. Memantine is proposed to counteract cellular damage due to pathological activation of NMDA receptors by glutamate. Results with Ginkgo biloba have been mixed. Data for neurotrophic therapies and vitamin E (tocopherol) appear promising but require confirmation. NSAIDs and conjugated estrogens have not proven to be of value to date for the treatment of Alzheimer's disease. Statins may have a potential role in reducing the risk or delaying the onset of Alzheimer's disease, although this has yet to be confirmed in randomised trials. There are currently no data to support the use of statins as a treatment for dementia. This article provides an update on the current status of selected agents, focusing primarily on those agents with the most extensive clinical evidence at present.

Alzheimer Disease↗
PubMed2002

Absence of nuclear factor kappaB inhibition by NSAIDs in hepatocytes.

Stimulation of fetal hepatocytes with proinflammatory cytokines and lipopolysaccharide promotes the expression of cyclooxygenase-2 (COX-2) and nitric oxide synthase-2 (NOS-2), whereas the hepatoma cell line HepG2 exhibits a behavior similar to that described for adult hepatocytes and only expresses NOS-2. The effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on the inflammatory onset was analyzed in these cells since in addition to the inhibition of cyclooxygenase activity, these drugs interfere with other signaling pathways related with the inflammatory response. Inhibition of nuclear factor kappaB (NF-kappaB) activation by aspirin and salicylate has been described in many cells. However, incubation of hepatic cells with salicylate, aspirin, indomethacin, ibuprofen, or 5,5-dimethyl-3(3-fluorophenyl)-4-(4-methylsulfonyl)phenyl-2(5H)-furanone (DFU), a fluorinated derivative of rofecoxib, failed to impair IkappaB kinase activity, the processing of NF-kappaB, and the expression of NF-kappaB-dependent genes, such as NOS-2. Moreover, selective COX-2 inhibitors did not promote apoptosis in hepatocytes under inflammatory conditions, suggesting that prostaglandins are not required to maintain cell viability. In conclusion, these data indicate that hepatocytes are not sensitive to NF-kappaB inhibition by NSAIDs and that these drugs, especially the COX-2 selective inhibitors, do not alter cell viability.

Animals↗
PubMed2004

Aprotinin: a pharmacologic overview.

Aprotinin is a polypeptide with serine protease inhibitory activity of key enzymes associated with inflammatory, fibrinolytic, and hemostatic pathways. The drug binds directly to the fibrinolytic plasmin at the lower plasmin-inhibiting dose (plasma concentration, 137 KIU/mL), and the inflammatory mediator, kallikrein, using the higher kallikrein-inhibiting dose (plasma concentration, >250 KIU/mL). Aprotinin inhibits platelet glycoprotein loss (GpIb and GpIIb/IIIa receptors) associated with cardiopulmonary bypass and has been described as platelet sparing. Current literature supports direct anti-inflammatory effects through modulation of neutrophil activation, attachment, and transmigration, with resultant blunting in the rise of proinflammatory cytokine levels and deleterious tissue damaging enzymes. The pharmacologic properties of aprotinin may lead clinicians to consider this therapy for use as a hemostatic and anti-inflammatory agent in surgeries beyond its established use in coronary artery bypass graft surgery.

Aprotinin↗
PubMed2005

Inflammatory modulation of PPAR gamma expression and activity.

Nitric oxide (NO) production increases with age in the lupus-prone MRL/lpr mouse, paralleling disease activity. One mechanism for excess NO production in MRL/lpr mice may be a defect in down-regulatory mechanisms of the iNOS pathway. A potential modulator of NO is the nuclear hormone receptor peroxisome proliferation activated receptor gamma (PPARgamma). We demonstrate that renal PPARgamma protein expression was altered as disease progressed in MRL/lpr mice, which paralleled increased iNOS protein expression. Additionally, MRL/lpr-derived primary mesangial cells expressed less PPARgamma than BALB/c mesangial cells and produced more NO in response to LPS and IFNgamma. Furthermore, PPARgamma activity was reduced in mesangial cells following exposure to inflammatory mediators. This activity was restored with the addition of a NOS enzyme inhibitor. These results indicate that the activation of inflammatory pathways may lead to reduced activity and expression of PPARgamma, further exacerbating the disease state.

Age Factors↗
PubMed2005

Human immunodeficiency virus-1 Tat protein up-regulates interleukin-6 and interleukin-8 expression in human breast cancer cells.

OBJECTIVE: To examine whether HIV-1 Tat protein increases the metastatic potential of human breast cancer cells through induction of pro-inflammatory tumor microenvironment. METHODS: Real-time RT-PCR and ELISA were employed to determine the mRNA and protein expression of IL-6 and IL-8 in highly metastatic human breast cancer cell line, MDA-MB-231. To investigate the transcriptional regulatory mechanisms of Tat-mediated up-regulation of IL-6 and IL-8, EMSA and reporter gene assay were carried out. RESULTS: Exposure of MDA-MB-231 cells to Tat resulted in a significant and dose-dependent up-regulation of IL-6 and IL-8 mRNA and protein expression. HIV-1 Tat protein also markedly increased NF-kappaB DNA-binding activity and transactivation in MDA-MB-231 cells. Additionally, pretreatment with NF-kappaB inhibitors significantly attenuated the ability of Tat to up-regulate IL-6 and IL-8 expression. It was also found that exposure of MDA-MB-231 cells to Tat induced up-regulation of MMP-9 expression at both mRNA and protein levels. CONCLUSIONS: These results suggest that HIV-1 Tat protein up-regulates expression of IL-6 and IL-8 in human breast cancer cells by NF-kappaB-dependent pathway. These data may contribute to exploration of the new molecular mechanisms leading to novel approaches for the therapeutic drug developments specifically targeted against the inflammatory pathways of breast cancer metastasis in AIDS patients.

Breast Neoplasms↗
PubMed1996

Transforming growth factor-beta 1 inhibits the production of IL-8 and the transmigration of neutrophils through activated endothelium.

A central mechanism of inflammation is the activation of vascular endothelium by the inflammatory cytokines TNF-alpha and IL-1. These cytokines induce the expression of adhesion molecules, the elaboration of chemokines, and the transendothelial migration of white cells. TGF-beta 1 has anti-inflammatory properties, is expressed in the vessel wall, and has previously been shown to inhibit leukocyte adhesiveness to the endothelium at least in part by inhibiting the expression of E-selectin. We now show that TGF-beta 1 also inhibits the migration of neutrophils through endothelial monolayers activated by TNF-alpha. At a dose of 10 U/ml TNF-alpha, the transmigration of neutrophils was inhibited 42.7 +/- 7.9% (n = 8) by 0.2 ng/ml TGF-beta 1. Furthermore, TGF-beta 1 inhibited, in a time- and dose-dependent fashion, the elaboration of IL-8 by TNF-activated endothelial cells by between 33 and 78% (TNF doses from 100 down to 0.1 U/ml) and the elaboration of mRNA for IL-8 by 69%. TGF-beta 1 treatment did not significantly alter the TNF-induced IL-8 mRNA stability, suggesting that the mechanism of action of TGF-beta 1 is on gene transcription. Neutrophil transmigration through cytokine-activated endothelium involves both IL-8-dependent and IL-8-independent mechanisms. Using an anti-IL-8 Ab, we show that TGF-beta 1 inhibits only the IL-8-dependent pathway, but does not affect the IL-8-independent transendothelial migration mechanism. These and our previous results show that TGF-beta1, achieves its anti-inflammatory properties by inhibiting the expression of at least two genes, E-selectin and IL-8, which are essential in the inflammatory pathway.

Cell Movement↗
PubMed2006

The unfolded protein response is an important regulator of inflammatory genes in endothelial cells.

OBJECTIVE: Oxidized 1-palmitoyl-2-arachidonyl-sn-3-glycero-phosphorylcholine (oxPAPC) accumulates in atherosclerotic lesions and in vitro studies suggest that it mediates chronic inflammatory response in endothelial cells (ECs). The goal of our studies was to identify pathways mediating the induction of inflammatory genes by oxPAPC. METHODS AND RESULTS: Using expression arrays, quantitative polymerase chain reaction (PCR), and immunoblotting we demonstrate that oxPAPC leads to endoplasmic reticulum stress and activation of the unfolded protein response (UPR) in human aortic ECs. Immunohistochemistry analysis of human atherosclerotic lesions indicated that UPR is induced in areas containing oxidized phospholipids. Using the UPR inducing agent tunicamycin and selective siRNA targeting of the ATF4 and XBP1 branches of the UPR, we demonstrate that these transcription factors are essential mediators of IL8, IL6, and MCP1 expression in human aortic ECs required for maximal inflammatory gene expression in the basal state and after oxPAPC treatment. We also identify a novel oxPAPC-induced chemokine, the CXC motif ligand 3 (CXCL3), and show that its expression requires XBP1. CONCLUSIONS: These data suggest that the UPR pathway is a general mediator of vascular inflammation and EC dysfunction in atherosclerosis, and, likely, other inflammatory disorders.

Activating Transcription Factor 4↗
PubMed2001

Interaction of bacteria and bacterial toxins with intestinal epithelial cells.

The epithelium of the intestinal tract is a key barrier between the external environment and the internal body environment. Intestinal epithelial cells are targets for luminal bacteria and viruses and must discriminate between pathogenic and nonpathogenic commensal organisms. Pathogenic bacteria and their secreted products influence epithelial cell function and induce diarrhea by numerous mechanisms that range from an effect on epithelial cell-cell associations to intracellular signal transduction pathways. These effects lead to an inflammatory response and an influx of neutrophils into the epithelium. Infiltrating neutrophils, in turn, signal to epithelial cells, induce a secretory response, and perpetuate the diarrhea. Conversely, commensal bacteria have the ability to suppress inflammatory responses by inhibiting specific intracellular signal transduction pathways. Some of these diverse host pathogenic responses are addressed in this review.

Animals↗
PubMed2003

The ubiquitin proteolytic system and pathogenesis of human diseases: a novel platform for mechanism-based drug targeting.

Until the early 1980s, protein degradation was a neglected research area, and scientists were mostly busy deciphering the genetic code and its translation to the proteome. Destruction of cellular proteins was thought to be a scavenger, non-specific and dead-end process. Although it was known that proteins do turn over, the large extent and high specificity of the process, whereby distinct proteins have half-lives that range from a few minutes to several days, was not appreciated. The discovery of the lysosome by Christian de Duve did not change this view significantly, as it was clear that this organelle is involved mostly in the degradation of extracellular proteins, and their proteases cannot be substrate-specific. The discovery of the complex cascade of the ubiquitin pathway revolutionized the field. It is clear now that degradation of cellular proteins via the ubiquitin system is a highly complex, temporally controlled and tightly regulated process that plays major roles in a variety of basic pathways and processes during cell life and death, and in health and disease. The system is involved in targeting many cellular proteins, among them cell cycle regulators, growth- and differentiation-controlling factors, transcriptional activators, cell-surface receptors and ion channels, endoplasmic reticulum proteins, antigenic proteins destined for presentation on class I MHC molecules, and abnormal/misfolded proteins. Consequently, it is involved in regulating many basic cellular processes, such as cell cycle and division, growth and differentiation, signal transduction and transcription, modulation of the secretory and endocytic pathways, the immune and inflammatory responses, and quality control. With the multitude of substrates targeted and the numerous processes involved, it is not surprising that aberrations in the pathway have been implicated in the pathogenesis of many diseases, with certain malignancies and neurodegenerative disorders being ranked among them.

Disease↗
PubMed2003

Pharmacologic treatment of acute renal failure in sepsis.

The pathophysiology of acute renal failure in sepsis is complex and includes intrarenal vasoconstriction, infiltration of inflammatory cells in the renal parenchyma, intraglomerular thrombosis, and obstruction of tubuli with necrotic cells and debris. Attempts to interfere pharmacologically with these dysfunctional pathways, including inhibition of inflammatory mediators, improvement of renal hemodynamics by amplifying vasodilator mechanisms and blocking vasoconstrictor mechanisms, and administration of growth factors to accelerate renal recovery, have yielded disappointing results in clinical trials. Interruption of leukocyte recruitment is a potential promising approach in the treatment of septic acute renal failure, but no data in humans are presently available. Activated protein C and steroid replacement therapy have been shown to reduce mortality in patients with sepsis and are now accepted adjunctive treatment options for sepsis in general.

Acute Kidney Injury↗
PubMed2001

Stress and the Gastrointestinal Tract IV. Modulation of intestinal inflammation by stress: basic mechanisms and clinical relevance.

The stress response in a healthy organism is generally viewed as a warning and thus a protective reaction to a threat. However, the response may be deleterious if it is linked to an inflammatory stimulus or if it proceeds an inflammatory event. Prior stress enhances the response to an inflammatory stimulus by a mechanism that is independent of the release of hypothalamic corticotropin-releasing factor (CRF) or arginine vasopressin. Putative mechanisms include an increase in intestinal permeability as well as the release of the proinflammatory neuropeptide substance P. Stress may also reactivate previous inflammation when applied in conjunction with a small luminal stimulus. This reactivation involves increased permeability and requires the presence of T lymphocytes. Inflammatory mediators activate hypothalamic pathways, and a negative feedback loop, mediated by CRF release, has been proposed because animals with impaired hypothalamic CRF responses are more susceptible to inflammatory stimuli. Together, these experimental observations provide insights into the expression of inflammatory disorders in humans, including inflammatory bowel disease and postinfective irritable bowel syndrome.

Animals↗
PubMed1991

Arachidonic acid metabolism: role in inflammation.

Arachidonic acid is oxygenated and further transformed into a variety of products which mediate or modulate inflammatory reactions. The cyclo-oxygenase pathway, which is inhibited by nonsteroidal anti-inflammatory drugs, produces vasodilator prostaglandins such as PGE2 and prostacyclin (PGI2) and also thromboxane A4, a potent platelet aggregating agent. Recent work has demonstrated the importance of products formed via various lipoxygenase-catalyzed reactions. Leukotrienes are formed by initial oxygenation at C-5 followed by further transformation to an unstable epoxide intermediate, leukotriene A4 (LTA4). The intermediate can be converted into LTB4 by hydrolysis and into LTC4 by conjugation with glutathione. The formation of the leukotriene, LTA4, is catalyzed by a 5-lipoxygenase possessing both lipoxygenase and LTA4-synthase activities. Unlike other lipoxygenases, this enzyme requires multiple stimulatory factors for maximal activity. These include Ca2+, ATP, and three non-dialyzable cellular components. The cDNAs for human 5-lipoxygenase and LTA4-hydrolase have recently been cloned and the amino acid sequences for the enzymes have been deduced. LTC4 and its metabolites, LTD4 and LTE4, increase vascular permeability and contract airway smooth muscle. Leukotriene B4 causes adherence of neutrophils to endothelial cells and is a potent chemotactic agent. It also stimulates release of lysosomal enzymes and generation of superoxide anion in neutrophils. Oxygenation of arachidonic acid at C-12 and C-15 generates products (5S, 12S-DHETE and 14,15-DHETE) which can modulate various neutrophil functions. A new group of arachidonic acid-derived products was recently discovered. These compounds (lipoxins), formed by oxygenation at C-5 and C-15 and additional reactions, contain a conjugated tetraene structure and three alcohol groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Arachidonic Acids↗
PubMed1997

An anti-inflammatory benzamide derivative inhibits the protein kinase C (PKC)-dependent pathway of ERK2 phosphorylation in murine macrophages.

We have previously described benzamide derivatives that inhibited tumor necrosis factor (TNF) production from activated macrophages (Mphi) probably by interacting with a protein kinase C (PKC)-dependent pathway. To investigate their mode of action further, we first tested their effect on isolated PKC in vitro, using the selective inhibitor bisindolylmaleimide (BIM) as a positive control. We found that our representative compound JM34 did not inhibit PKC activity in vitro. We then investigated pathways located downstream of PKC and focused on the Raf1/MEK1,2/Erk1,2 cascade known to be preferentially activated by PKC activators such as phorbol esters. We found that JM34 dose-dependently inhibited Erk2 phosphorylation in Mphi stimulated by phorbol dibutyrate and calcium ionophore (maximal inhibition of 85% at 300 microM). BIM at 3 microM totally abrogated Erk2 phosphorylation. After stimulation with endotoxin or zymosan, Erk2 phosphorylation was only partially inhibited (25-30%) by JM34 or BIM, which confirmed that PKC-independent events were also involved in Erk2 phosphorylation. Because activated Erk2 has been shown to activate phospholipase A2, we tested the effect of JM34 and BIM on the release of arachidonate metabolites from activated Mphi. We found that both products partially inhibited the release of arachidonate metabolites from zymosan-activated Mphi at levels comparable to their inhibition of Erk2 phosphorylation. In contrast, JM34 and BIM markedly differed in their ability to inhibit TNF production. Taken together, our results suggest that JM34 inhibited the PKC-dependent pathway of Erk2 phosphorylation, which may fully account for its inhibitory effect on phospholipase A2 activation. However, the inhibition of TNF release by JM34 probably involved inhibition of an additional pathway, distinct from the Erk1/Erk2 cascade.

Animals↗
PubMed2000

The protein C pathway.

OBJECTIVE: To examine the role of the protein C anticoagulant pathway in the regulation of microvascular thrombosis. The mechanisms by which inflammation impairs the function of this pathway are also reviewed; conversely, we will survey emerging knowledge of the multiple mechanisms by which the protein C anticoagulant pathway can control the inflammatory response. DATA SOURCES: The information reviewed here was taken from the primary literature, including recent abstracts. STUDY SELECTION: All studies that bear directly on the interrelationship between the protein C anticoagulant pathway and inflammation were included, as was a summary of the initial clinical experience with protein C/activated protein C therapy in sepsis. DATA EXTRACTION AND SYNTHESIS: The results from each of the experimental approaches are summarized. Clinical experience with protein C supplementation in sepsis, although promising, is still in the early stages of study. CONCLUSIONS: The protein C anticoagulant pathway is a major mechanism in controlling microvascular thrombosis. Protein C deficiency that can occur in sepsis facilitates thrombin generation in the microvasculature, probably augmenting inflammatory responses and contributing to endothelial cell dysfunction. Animal studies and preliminary clinical results suggest that protein C/activated protein C supplementation may be useful in reversing microvascular dysfunction.

Animals↗
PubMed1984

Physiological and pharmacological regulation of prostaglandin and leukotriene production by macrophages.

The synthesis and secretion of prostaglandins and leukotrienes by mouse peritoneal macrophages is under several regulatory controls. Arachidonic acid must first be released from phospholipid stores by the action of phospholipases. Macrophages have the capacity to deacylate arachidonic acid directly from the SN2 position of phospholipids via the action of a phospholipase A2. In addition, these cells contain a phospholipase C capable of removing inositol-phosphate from phosphatidylinositol generating diacylglycerol. Another enzyme, diacylglycerol lipase is present to then generate arachidonic acid. The free arachidonic acid then enters the cyclooxygenase pathway to generate prostaglandins, the lipoxygenase pathway to generate leukotrienes or both pathways. The nature of the inflammatory stimulus added to these cells determines which of the above pathways become operative. Zymosan and the Ca++ ionophore, A23187 stimulate the synthesis of both prostaglandins and leukotrienes whereas phorbol myristate acetate and lipopolysaccharide induce only the synthesis of prostaglandins. In addition, the synthesis of these two products by macrophages can be regulated by certain antiinflammatory compounds. Indomethacin, aspirin, ibuprofen and benoxaprofen are only inhibitors of the prostaglandin pathway, whereas BW755C, 5,8,11-ETYA, NDGA and sulindac sulfide (high doses) are inhibitors of the synthesis of both prostaglandins and leukotrienes. Dapsone, an effective drug for leprosy, also inhibits the synthesis of both of these products.

Animals↗
PubMed2003

Cholinergic pathways modulate experimental dinitrobenzene sulfonic acid colitis in rats.

Recent studies have suggested that neuroimmune interactions modulate intestinal mucosal immune responses. In the current study, we examined the role of cholinergic pathways in modulating the severity of acute dinitrobenzene sulfonic acid colitis, using pharmacological agents to suppress acetylcholinesterase in Sprague-Dawley rats, and evaluating the colitis in the cholinergic hyperresponsive Flinder's sensitive line rats and their control counterparts, the Flinder's resistant line. Colitis was induced by intrarectal dinitrobenzene sulfonic acid (80 mg x ml(-1) in 50% ethanol); controls received intrarectal saline. Sprague-Dawley rats received an acetylcholinesterase inhibitor, physostigmine (50 microg x kg(-1) s.c.) or neostigmine (50 microg x kg(-1) s.c.), 30 min prior to intrarectal dinitrobenzene sulfonic acid; controls received saline vehicle. On day 5, the macroscopic damage score, myeloperoxidase activity (an estimate of granulocyte infiltration) and smooth muscle thickness were evaluated in the inflamed colonic segment. Significant increases in macroscopic damage score and colonic smooth muscle thickness were observed in Sprague-Dawley and Flinder's Resistant Line rats on day 5 following intrarectal dinitrobenzene sulfonic acid compared to saline controls. Increased myeloperoxidase activity was also observed in dinitrobenzene sulfonic acid-treated Sprague-Dawley rats and Flinder's Resistant Line rats. In contrast, Flinder's Sensitive Line rats failed to demonstrate a significant rise in macroscopic damage, smooth muscle layer thickness, or myeloperoxidase activity on day 5 following intrarectal dinitrobenzene sulfonic acid when compared to saline-treated Flinder's Sensitive Line controls. Neostigmine and physostigmine treatment prior to intrarectal dinitrobenzene sulfonic acid significantly attenuated macroscopic damage score, myeloperoxidase activity and smooth muscle thickness on day 5 compared to colitic Sprague-Dawley controls. Significantly greater reductions in myeloperoxidase activity were observed with physostigmine vs. neostigmine pretreatment. These data suggest that cholinergic pathways modulate the acute colonic inflammatory response associated with the dinitrobenzene sulfonic acid model, with central pathways exerting a greater protective effect relative to peripheral pathways. Further studies are required to determine the contributions of sites in the nervous system and neuro-effector junctions.

Animals↗
PubMed2004

Apoptosis in the intestinal mucosa of patients with inflammatory bowel disease: evidence of altered expression of FasL and perforin cytotoxic pathways.

BACKGROUND AND AIMS: Abnormal apoptosis may result in the persistence of activated intestinal T-cells in inflammatory bowel disease (IBD). We investigated apoptosis in distinct mucosal compartments, and the expression of Fas/Fas ligand and perforin in the inflamed and non-inflamed intestinal mucosa of patients with IBD. METHODS: Colon specimens from 15 patients with ulcerative colitis (UC) and inflamed and non-inflamed mucosa from 15 patients with Crohn's disease (CD) were analysed for densities and distribution of apoptotic cells determined by the terminal deoxynucleotidyltransferase-mediated dUDP-biotin nick-end labelling (TUNEL) method. Fas, FasL, and perforin-expressing cells were assessed by immunoperoxidase, and with anti-CD3, anti-CD20 and anti-CD68, by double immunofluorescence with confocal microscopy. Quantitative analysis was performed using a computer-assisted image analyser. RESULTS: Colonic lamina propria (LP) and epithelium from patients with UC showed higher rates of apoptosis than controls, but no difference was shown regarding patients with CD. In LP, co-expression of Fas was reduced with T-cells in inflamed CD mucosa, and with macrophages in all patients with IBD. No difference was found in the expression of Fas on B-cells. Rates of FasL-expressing cells in LP were higher in IBD than in controls, with no correlation with the rates of apoptosis. Rates of perforin-expressing cells in LP were greater in UC than in controls, and correlated to the rates of apoptosis. No difference was shown regarding the inflamed and non-inflamed CD mucosa. Rates of FasL and perforin-expressing intra-epithelial lymphocytes showed no difference among groups. CONCLUSIONS: Increased expression of FasL in IBD colonic LP not parallelled by Fas on T-cells and macrophages may indicate a reduced susceptibility to the Fas/FasL-mediated apoptosis of lymphoid cells. Expression of perforin is correlated to the tissue damage, and may represent the enhancement of a distinct cytotoxic pathway in UC.

Adolescent↗