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PubMed1997

Effects of tepoxalin, a dual inhibitor of cyclooxygenase/5-lipoxygenase, on events associated with NSAID-induced gastrointestinal inflammation.

Prostaglandins and thromboxanes are products of arachidonic acid metabolism via the cyclooxygenase (CO) enzyme and are responsible for the pain and swelling common to sites of inflammation. Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the production of these substances and are used in the treatment of inflammatory diseases such as arthritis. However, one of the major side-effects of NSAID therapy is gastric ulceration. It is possible that inhibition of prostaglandin production and a related increase in the formation of leukotrienes via the 5-lipoxygenase (5-LO) enzymatic pathway are responsible for attracting inflammatory cells, causing local sites of inflammation and producing ulceration. To determine the effects of 5-LO inhibition on this hypothesis, studies were performed in rats to evaluate the effects of tepoxalin, a dual CO/LO inhibitor on leukotriene B4 levels in gastric mucosa and neutrophil adhesion in mesenteric venules. In rats, chronic oral administration of an NSAID, indomethacin (2 mg/kg daily over 4 days), resulted in 40% mortality, accompanied by intestinal adhesions and perforations when evaluated 24 h after the fourth dose of drug. Additionally, neutrophil adhesion was increased in the mesenteric venules and cell infiltration was evident in the mesenteric interstitium. These gastrointestinal side-effects were inhibited in a separate group of rats administered tepoxalin (20 mg/kg, p.o) 30 min prior to each daily indomethacin treatment. Further studies were performed to determine tepoxalin's effects on early events associated with NSAID-induced gastrointestinal inflammation, including neutrophil adhesion, lipid peroxide generation and LTB4 production. Indomethacin (100 mg/kg, p.o.) produced elevated levels of LTB4 in rat gastric mucosa 90 min after administration. Additionally, neutrophil adhesion in mesenteric venules was increased at this dose and with the administration of another NSAID, naproxen. No generation of lipid peroxides was evident in the gastric mucosa at this timepoint. Tepoxalin (up to 400 mg/kg, p.o.) did not have an effects on gastric mucosal LTB4 generation and lipid peroxide levels. A decrease in neutrophil adhesion was observed at the highest dose. In another study, pretreatment with tepoxalin (ED50=7.5 mg/kg, p.o.) or the selective 5-LO inhibitor zileuton (100 mg/kg, p.o.) prevented the increases in gastric mucosal LTB4 levels and neutrophil adhesion induced by indomethacin (100 mg/kg, p.o.). These data suggest that LO inhibition may play a vital role in the prevention of NSAID-induced gastric inflammation, providing insight into the lack of ulcerogenicity with tepoxalin and new approaches to anti-inflammatory therapy which may prevent gastric side effects.

Animals↗
PubMed1994

Inflammatory bowel disease in children.

Inflammatory bowel disease in children and adults remains the most challenging problem in gastroenterology. There is an increasing body of immunologic and genetic evidence to suggest that Crohn's disease and ulcerative colitis are different diseases, but that once inflammation begins, many common secondary pathways of inflammation are initiated. The major recent conceptual advance is the observation that mice in whom different immunoregulatory pathways are disrupted develop an inflammatory bowel disease. In the case of interleukin-2 knockout mice, the lesion restricted to the colon, is virtually identical to ulcerative colitis in humans, and is initiated by the normal bacterial flora. Yet these mice possess anticolon antibodies, long-considered to be of pathologic significance in ulcerative colitis. These animal models will allow detailed longitudinal studies to be done, and less reliance will need to be placed on cross-sectional studies of chronically inflamed gut from patients.

Age Factors↗
PubMed2005

Modulating bladder neuro-inflammation: RDP58, a novel anti-inflammatory peptide, decreases inflammation and nerve growth factor production in experimental cystitis.

PURPOSE: In interstitial cystitis (IC) inflammation induces and perpetuates neurotrophic changes in the bladder, resulting in the symptoms of frequency, urgency and pain. RDP58 (NH2-arg-norleucine (nle)-nle-arg-nle-nle-nle-gly-tyr-CONH2) (Sangstat Corp., Fremont, California) is a novel synthetic peptide that inhibits early signal transduction pathways for the expression of inflammatory cytokines. In this study we evaluated the effects of intravesical RDP58 on an established model of cystitis. MATERIALS AND METHODS: Mice were catheterized and equal volumes of Escherichia coli lipopolysaccharide (LPS) or saline were instilled into the bladder. After 45 minutes the bladders were drained and distilled water or RDP58 (1 mg/ml) was instilled for 30 minutes. At 24 hours later the bladders were excised and cultured for analysis of tumor necrosis factor-alpha (TNF-alpha), substance P (SP) and nerve growth factor (NGF) production, as quantified by enzyme-linked immunosorbent assay. RESULTS: LPS caused severe inflammation in mouse bladders compared with controls. Exposure to LPS increased the levels of TNF-alpha, SP and NGF production compared with controls (each p <0.05). In LPS exposed mice RDP58 significantly decreased inflammatory parameters by 82% 24 hours after treatment (p <0.05). Within 4 hours RDP58 abolished TNF-alpha production and at 24 hours TNF-alpha remained undetectable. RDP58 also significantly decreased SP and NGF production in LPS exposed bladders by more than 40% and 85%, respectively (each p <0.05). CONCLUSIONS: Inflammatory models of cystitis result in increased levels of TNF-alpha, SP and NGF production in the bladder, paralleling the hypothesized neuro-inflammatory etiology of IC. RDP58 decreases inflammation and neurotrophic factors in vivo and it may potentially treat bladder disorders with an inflammatory component, such as IC.

Animals↗
PubMed2006

Insulin therapy is associated with platelet dysfunction in patients with type 2 diabetes mellitus on dual oral antiplatelet treatment.

OBJECTIVES: This study sought to assess the influence of type 2 diabetes mellitus (T2DM) and the impact of hypoglycemic treatment (insulin vs. noninsulin) on platelet function profiles in patients treated with dual oral antiplatelet therapy. BACKGROUND: Insulin inhibits platelet aggregation by suppressing the P2Y12 pathway. However, T2DM patients have a loss of responsiveness to insulin that leads to upregulation of the P2Y12 pathway, increased platelet reactivity, and reduced responsiveness to antiplatelet agents. Patients with insulin-treated diabetes mellitus (ITDM) have a more advanced disease status and higher atherothrombotic risk compared with non-ITDM (NITDM). However, the impact of insulin therapy on platelet dysfunction in patients treated with P2Y12 antagonists is unknown. METHODS: A total of 201 T2DM and 65 nondiabetic patients with coronary artery disease in a steady phase of aspirin and clopidogrel treatment were studied. Platelet aggregation was assessed using agonists specific (6 and 20 microM adenosine diphosphate [ADP]) and nonspecific (6 microg/ml collagen and 20 microM epinephrine) for the P2Y12 pathway. High shear-induced platelet reactivity was assessed by means of the PFA-100 system (Dade-Behring International, Miami, Florida). RESULTS: The T2DM patients had platelet aggregation and shear-induced platelet function significantly increased compared with nondiabetic patients using all assays. Platelet aggregation was increased in ITDM (n = 68) compared with NITDM (n = 133) patients after P2Y12-specific stimuli. Insulin treatment was the strongest predictor of ADP-induced aggregation. Platelet function profiles were similar between ITDM and NITDM using assays nonspecific to the P2Y12 pathway. Platelet dysfunction was independent of glycemic control and inflammatory status. CONCLUSIONS: The P2Y12-dependent and -independent pathways of platelet reactivity are altered in T2DM compared with nondiabetic patients, and ITDM have greater ADP-induced platelet aggregation compared with NITDM.

Aged↗
PubMed2005

Effects of Leontice smirnowii tuber monodesmosides and crude extract in carrageenan- and histamine-induced acute inflammation model of rats.

Leontice smirnowii is a member of the Berberidaceae family. We have recently reported the 1,1-diphenyl-2-picryl-hydrazyl radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, reducing power and metal chelating activities of L. smirnowii products. In the current study we investigated the possible effects of the crude extracts of L. smirnowii (CELS) and the monodesmoside's purified extract (MPE) of L. smirnowii in the carrageenan- and histamine-induced acute inflammation models in rats. The experiment revealed that CELS and MPE have anti-inflammatory effects, dose dependently in carrageenan-induced acute inflammation. On the other hand, their proinflammatory effects were surprisingly observed, especially in low doses, in the histamine-induced acute inflammation model. Summarizing these data, we may state that CELS and MPE exert their anti-inflammatory effects via non-histaminergic pathways.

Animals↗
PubMed2002

Mutations in CD2BP1 disrupt binding to PTP PEST and are responsible for PAPA syndrome, an autoinflammatory disorder.

PAPA syndrome (pyogenic sterile arthritis, pyoderma gangrenosum, and acne, OMIM #604416) and familial recurrent arthritis (FRA) are rare inherited disorders of early onset, primarily affecting skin and joint tissues. Recurring inflammatory episodes lead to accumulation of sterile, pyogenic, neutrophil-rich material within the affected joints, ultimately resulting in significant destruction. We recently localized the genes for PAPA syndrome and FRA to chromosome 15q and suggested that they are the same disorder. We have now established this by the identification of co-segregating disease-causing mutations in the CD2-binding protein 1 (CD2BP1; GenBank accession no XM 044569) gene in the two reported families with this disorder. E250Q or A230T amino acid substitutions occur within a domain highly homologous to yeast cleavage furrow-associated protein CDC15. CD2BP1 and its murine ortholog, proline-serine-threonine phosphatase interacting protein (PSTPIP1), are adaptor proteins known to interact with PEST-type protein tyrosine phosphatases (PTP). Yeast two-hybrid assays demonstrate severely reduced binding between PTP PEST and both the E250Q and A230T mutant proteins. Previous evidence supports the integral role of CD2BP1 and its interacting proteins in actin reorganization during cytoskeletal-mediated events. We hypothesize that the disease-causing mutations that we have identified compromise physiologic signaling necessary for the maintenance of proper inflammatory response. Accordingly we suggest classification of PAPA syndrome as an autoinflammatory disease. This CD2BP1-mediated biochemical pathway(s) may function in common inflammatory disorders with apparent etiological overlap, such as rheumatoid arthritis and inflammatory bowel disease.

Acne Vulgaris↗
PubMed2003

Phyllanthus amarus has anti-inflammatory potential by inhibition of iNOS, COX-2, and cytokines via the NF-kappaB pathway.

BACKGROUND/AIMS: Phyllanthus amarus is a herbal medicine traditionally applied in the treatment of viral hepatitis. Aim of this study was to investigate potential anti-inflammatory properties of standardized P. amarus extracts concerning a potential influence of P. amarus on endotoxin-induced nitric oxide synthase (iNOS), cyclooxygenase (COX-2), and cytokine production in vivo and in vitro. METHODS: Investigations were performed in rat Kupffer cells (KC), in RAW264.7 macrophages, in human whole blood, and in mice. Cells were stimulated with lipopolysaccharides (LPS) in the presence or absence of P. amarus extracts (hexane, EtOH/H(2)O), mice were treated with galactosamine/LPS as a model for acute toxic hepatitis. Nitrite was measured by Griess assay, prostaglandin E(2) (PGE(2)) by radioimmunoassay, and cytokines by enzyme-linked immunosorbent assay. iNOS and COX-2 were determined by Western blot, activation of NF-kappaB and AP-1 by EMSA. RESULTS: P. amarus EtOH/H(2)O and hexane extracts showed an inhibition of LPS-induced production of NO and PGE(2) in KC and in RAW264.7. The extracts also attenuated the LPS-induced secretion of tumor necrosis factor (TNF-alpha) in RAW264.7 as well as in human whole blood. Both extracts reduced expression of iNOS and COX-2 and inhibited activation of NF-kappaB, but not of AP-1. P. amarus inhibited induction of interleukin (IL)-1beta, IL-10, and interferon-gamma in human whole blood and reduced TNF-alpha production in vivo. CONCLUSIONS: This work shows that standardized extracts of P. amarus inhibit the induction of iNOS, COX-2, and TNF-alpha. Therefore, we report for the first time an anti-inflammatory potential of this traditionally employed herbal medicine both in vitro and in vivo.

Animals↗
PubMed2005

Novel role of lipoxygenases in the inflammatory response: promotion of TNF mRNA decay by 15-hydroperoxyeicosatetraenoic acid in a monocytic cell line.

The metabolism of arachidonic acid via the lipoxygenase and cyclooxygenase pathways generates metabolites that regulate the inflammatory response. Although products of lipoxygenase are classically proinflammatory, recently it has been demonstrated that lipoxins, 15-hydroperoxyeicosatetraenoic acid (15-HPETE) and 15-hydroxyeicosatetraenoic acid exhibit anti-inflammatory activity. We now demonstrate for the first time that 15-HPETE regulates the production of the proinflammatory cytokine TNF posttranscriptionally by promoting degradation of LPS-induced TNFmRNA in a human monocytic cell line, Mono Mac 6. 15-HPETE causes a significant increase in the rate of TNF but not G3PDHmRNA degradation in the presence of the transcription inhibitor, actinomycin D. The decay of TNFmRNA is accelerated 1.7-fold, and its half-life is decreased by 57%. In view of its chemical and physical properties, we propose that 15-HPETE may function by destabilizing TNFmRNA by interaction with a trans-activating protein bound to the AU-rich element of TNFmRNA.

Arachidonic Acid↗
PubMed1982

Evidence for two sources of arachidonic acid for oxidative metabolism by mouse peritoneal macrophages.

The products of arachidonic acid oxygenations by resident mouse peritoneal macrophages have been found to depend upon the nature of the stimulus. For example, soluble membrane-mediated inflammatory stimuli such as phorbol myristate acetate and lipopolysaccharide stimulated the formation of prostaglandin E2 via the cyclooxygenase pathway. In contrast, zymosan, a particulate, phagocytozable inflammatory mediator stimulated leukotrienes C4 and B4 synthesis via the lipoxygenase pathway in addition to stimulating prostaglandin E2 synthesis. Thus, the release of leukotrienes is not necessarily linked to the release of prostaglandins in a cell that has the enzymatic capability of producing both mediators. This suggests that the prostaglandin synthetase system can obtain substrate arachidonic acid from a source different from that for leukotriene synthesis.

Animals↗
PubMed2003

Diabetes-induced oxidative stress and low-grade inflammation in porcine coronary arteries.

BACKGROUND: Multiple pathways contribute to accelerated coronary atherosclerosis in diabetics, including increased oxidative stress and inflammatory burden. Accordingly, the mechanisms of abnormal formation of reactive oxygen species and the changes in inflammatory gene expression were examined in diabetic coronary arteries. METHODS AND RESULTS: In pigs with streptozotocin-induced diabetes, superoxide formation was augmented in coronary media and adventitia because of increased NAD(P)H oxidase activity (3 months) accompanied by upregulated expression of its cytosolic subunit, p22phox. Diabetes-induced oxidative stress resulted in the inflammatory response in the adventitia (increased expression of interleukin-6, tumor necrosis factor-alpha, monocyte chemotactic protein-1, vascular cell adhesion molecule-1 [VCAM-1]) and in the media (VCAM-1). To examine the mechanisms of these changes, studies with isolated coronary fibroblasts were undertaken. Advanced glycation end products (AGEs), rather than glucose itself, upregulated expression of interleukin-6, VCAM-1, and monocyte chemotactic protein-1 mRNAs. These results were paralleled by increased interleukin-6 secretion (P<0.01) and augmented leukocyte adhesion to AGE-stimulated coronary cells (P<0.001). AGEs increased expression of phosphorylated forms of mitogen-activated protein kinases in coronary cells (ERK1/2 and JNK) and resulted in redox-sensitive expression of inflammatory genes that was inhibited by several inhibitors of oxidative pathways [NAD(P)H oxidase inhibitors, N-acetylcysteine, and pyrrolidine dithiocarbamate]. CONCLUSIONS: Diabetes increased NAD(P)H oxidase activity and oxidative stress, producing inflammatory responses in porcine coronary media and adventitia. AGEs activated ERK1/2 and JNK signaling pathways and induced the expression of several inflammatory genes in coronary cells in a redox-sensitive manner. These results suggest the involvement of AGEs in the development of accelerated coronary atherosclerosis in diabetes.

Animals↗
PubMed2002

Inhibition of glutathione-related enzymes augments LPS-mediated cytokine biosynthesis: involvement of an IkappaB/NF-kappaB-sensitive pathway in the alveolar epithelium.

The regulation of lipopolysaccharide (LPS)-mediated pro-inflammatory cytokine biosynthesis by reduction-oxidation (redox)-sensitive enzymes involved in maintaining intracellular glutathione homeostasis was investigated in fetal alveolar type II epithelial cells (fATII). Inhibition of glutathione-oxidized disulfide reductase, which recycles GSSG --> 2GSH, by the action of 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) augmented LPS-dependent secretion of interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)-alpha. BCNU increased [GSSG] concentration at the expense of [GSH], thereby favoring oxidation equilibrium. Inhibition of gamma-glutamylcysteine synthetase, the rate-limiting enzyme in the biosynthesis of GSH, by the action of L-buthionine-(S,R)-sulfoximine (BSO), potentiated LPS-induced IL-1beta, IL-6 and TNF-alpha production. Similar to BCNU, BSO depleted [GSH] and induced the accumulation of [GSSG]. BCNU and BSO reduced LPS-mediated phosphorylation of inhibitory-kappaB (IkappaB-alpha), allowing its cytosolic accumulation. This effect was associated with the inhibition of the nuclear translocation of selective nuclear factor (NF)-kappaB subunits: NF-kappaB1 (p50), RelA (p65), RelB (p68) and c-Rel (p75), but not NF-kappaB2 (p52). BCNU and BSO reduced LPS-induced NF-kappaB activation as determined by the electrophoretic mobility shift DNA-binding assay. Analytical analysis of the effect of modulating the dynamic redox ratio ([GSH]+[GSSG])/[GSSG] revealed a novel role for GSSG as a disulfhydryl compound which mediates an inhibitory effect on NF-kappaB activation. It is concluded that selective modulation of redox-sensitive enzymes has an immunopharmacological potential in regulating pro-inflammatory cytokines and that the TkappaB-alpha/NF-kappaB pathway is redox-sensitive and differentially involved in mediating redox-dependent regulation of cytokine signaling.

Animals↗
PubMed2006

Inhibition of p38 mitogen-activated protein kinase enhances c-Jun N-terminal kinase activity: implication in inducible nitric oxide synthase expression.

BACKGROUND: Nitric oxide (NO) is an inflammatory mediator, which acts as a cytotoxic agent and modulates immune responses and inflammation. p38 mitogen-activated protein kinase (MAPK) signal transduction pathway is activated by chemical and physical stress and regulates immune responses. Previous studies have shown that p38 MAPK pathway regulates NO production induced by inflammatory stimuli. The aim of the present study was to investigate the mechanisms involved in the regulation of inducible NO synthesis by p38 MAPK pathway. RESULTS: p38 MAPK inhibitors SB203580 and SB220025 stimulated lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) expression and NO production in J774.2 murine macrophages. Increased iNOS mRNA expression was associated with reduced degradation of iNOS mRNA. Treatment with SB220025 increased also LPS-induced c-Jun N-terminal kinase (JNK) activity. Interestingly, JNK inhibitor SP600125 reversed the effect of SB220025 on LPS-induced iNOS mRNA expression and NO production. CONCLUSION: The results suggest that inhibition of p38 MAPK by SB220025 results in increased JNK activity, which leads to stabilisation of iNOS mRNA, to enhanced iNOS expression and to increased NO production.

Animals↗
PubMed2002

Mitogen-activated protein kinases.

The cellular control switches are regulated through an extensive network of interactive intracellular signal transduction pathways, such as the mitogen-activated protein kinase (MAPK) family. The MAPK pathways may play an important role in the inappropriate inflammatory responses that lead to systemic inflammatory response syndrome or multiple organ dysfunction syndrome. Therefore, elucidating the activation status of the MAPK pathways may be a method to identify patients at risk for systemic inflammatory response syndrome/multiple organ dysfunction syndrome. Also, manipulating the proper pathways may improve patients' outcomes. However, the MAPK family is part of a complex interactive network, which may initiate an unpredictable reaction to the indiscriminate inhibition or activation of a single component. A major challenge is to elucidate the principles by which the network is assembled, so a more tissue- and temporal-specific approach can be used.

Critical Care↗
PubMed1991

Pathways of substance P stimulation of canine tracheal ciliary beat frequency.

Substance P (SP), an inflammatory neuropeptide, may be released by intraepithelial nerves in response to an irritant or inflammatory stimulus. To investigate the neural and humoral pathways mediating the response of tracheal ciliary beat frequency (CBF) to topically applied SP, CBF was measured on the ventral midtracheal surface of anesthetized beagles by using heterodyne-mode correlation analysis laser light scattering. In the first study, aerosolized SP, delivered to the lungs of eight beagle dogs, stimulated CBF in a dose-dependent manner from a baseline of 4.9 +/- 0.4 Hz to a maximum of 14.9 +/- 1.5 Hz at dose of 10(-7) M. In the second study, the tracheal lumen was isolated from the bronchial airways by inflating the cuff of an endotracheal tube near the carina. Intravenous hexamethonium bromide (2 mg/kg), ipratropium bromide (0.5 micrograms/kg), and indomethacin (2 mg/kg) were used as blocking agents to inhibit the nicotinic, muscarinic, and cyclooxygenase pathways, respectively. Aerosolized 10(-9), 10(-8), or 10(-7) M SP was delivered sequentially to the tracheal lumen for 3 min at 30-min intervals. SP caused two distinct CBF stimulatory episodes at 4 min (mean time of the maximal response) and at 18 min (mean time of the maximal response) after onset of delivery and returned to baseline after 25 min. SP stimulated CBF from the baseline of 5.1 +/- 0.4 Hz to a maximum of 14.2 +/- 2.5 Hz during the first episode (P less than 0.01) and to 10.4 +/- 0.6 Hz during the second episode (P less than 0.01) at dose of 10(-8) M. These responses were inhibited by all the blocking agents. These data suggest that SP stimulates CBF via a cyclooxygenase-dependent parasympathetic reflex.

Aerosols↗
PubMed2003

Current insights into the pathogenesis, diagnosis and therapy of inflammatory cardiomyopathy.

Persistence of cardiotropic viruses (enterovirus, adenovirus) and anticardiac autoimmunity constitute the predominant etiopathogenic pathways of dilated cardiomyopathy (DCM). The diagnosis of inflammatory cardiomyopathy (InfCM) imposes sensitivity and specificity requirements, which are not fulfilled by the histological Dallas Criteria. The immunohistological quantification and characterization of immunocompetent infiltrates and cell adhesion molecule (CAM) expression has endorsed a new entity of secondary cardiomyopathies acknowledged by the World Health Organization (WHO), InfCM, in approximately 50% of DCM patients. In the absence of viral persistence, InfCM patients benefit from immunosuppressive treatment. Enteroviral and adenoviral genomes have been detected in a significant proportion of DCM patients. Enteroviral persistence is associated with an adverse prognosis. The induction of the coxsackie-adenovirus receptor (CAR) exclusively in 63% of DCM patients, but not in other cardiomyopathies, might constitute a key molecular determinant for cardiotropic viral infections in DCM. In InfCM patients with enterovirus or adenoviral persistence, interferon-beta administration leads to viral elimination and cessation of the intramyocardial inflammation, paralleled by a significant improvement of left ventricular systolic function and heart failure symptoms. The biopsy-guided etiopathogenic differentiation of DCM has endorsed specific treatment strategies: immunosuppressive regimens are favorable in autoimmune InfCM, whereas patients with viral persistence benefit from antiviral immunomodulation.

Cardiomyopathy, Dilated↗
PubMed2000

Post-transcriptional regulation of pro-inflammatory gene expression.

The cytokine tumour necrosis factor (TNF)alpha is a vital mediator of the innate immune response, and a pleiotropic regulator of cellular function. Its involvement in rheumatoid arthritis is illustrated by the clinical benefits of TNF alpha blockade. Post-transcriptional regulation (the control of mRNA stability and translation) appears to play a critical role in the regulation of TNF alpha expression by mitogen activated protein kinase signal transduction pathways and by anti-inflammatory agents. The aim of this article is to review some recent advances in our understanding of these processes, and to speculate on mechanisms of regulation of TNF alpha and other pro-inflammatory genes.

Humans↗
PubMed2001

Influence of glutamine on cytokine production by human gut in vitro.

BACKGROUND: glutamine modulates cytokine production by immune cells in vitro and protects the gut from experimental enterocolitis, but data on the effect of glutamine on cytokine production in human gut are lacking. AIM: to assess the effect of glutamine pre-treatment in vivo and in vitro on cytokine production by intestinal mucosa. METHODS: nine fasted volunteers received either enteral glutamine or saline over 6 h in a cross-over design. Duodenal biopsies were cultured for 24 h with or without glutamine. Cytokine content of culture media was analysed by ELISA, and the expression of cytokine mRNA in biopsies was assessed by semi-quantitative RT-PCR. RESULTS: glutamine given in vivo and in vitro significantly decreased IL-6 [1.4 (0.8-8.5) vs 8.9 (1.0-43.9)] and IL-8 production [5.8 (0-51.4) vs. 53.0 (2.5-114.6), pg/mg wet tissue], median (range), both P< or =0.01, in comparison to no glutamine experiments. Glutamine did not influence IL-4 production. IL-1beta, IL-10 and TNF-alpha were not detectable in culture media. The expression of any cytokine mRNA was not influenced by glutamine. CONCLUSIONS: glutamine reduces pro-inflammatory cytokine production by human intestinal mucosa, probably by a post-transcriptional pathway. Glutamine could be useful to modulate inflammatory conditions with imbalanced cytokine production.

Adolescent↗
PubMed2005

Humoral theory of transplantation: mechanism, prevention, and treatment.

We discuss the potential mechanisms of antibody-induced primary endothelium injury, which includes complement-dependent pathway (membrane attack complex formation, recruitment of inflammatory cells, and complement-complement receptor-mediated phagocytosis) and complement independent pathway antibody-dependent cell cytotoxicity. Secondary to endothelium injury, the following pathological reactions are found to be responsible for progressive tissue injury and final graft function loss: platelet activation and thrombosis, pathological smooth muscle and endothelial cell proliferation, and humoral and/or cellular infiltrate-mediated parenchyma damage after endothelium injury. We also introduce three categories of therapeutic strategy in the prevention and treatment of antibody-mediated rejection: (1) inhibition and depletion of antibody producing cells (immunosuppressants, antilymphocyte antibodies, splenectomy); (2) removal or blockage of preexisting or newly developed antibodies (immunoadsorption, plasmapheresis/plasma exchange, intravenous immunoglobulin); and (3) impediment or postponement of antibody-mediated primary and secondary tissue injury (anticoagulation, glucosteroids). In conclusion, because alloantibodies have destructive effect on allografts, alloantibody monitoring becomes extremely important. It will help clinicians to determine a patient's humoral responses against allograft and will therefore direct clinicians to optimize and/or minimize immunosuppressive drug therapy.

Animals↗