Prostanoids in bronchoalveolar lavage fluid do not predict outcome in congenital diaphragmatic hernia patients

Vasoactive prostanoids may be involved in persistent pulmonary hypertension (PPH) in infants with a congenital diaphragmatic hernia (CDH). We hypothesized that increased levels of prostanoids in bronchoalveolar lavage (BAL) fluid would predict clinical outcome. We measured the concentrations of 6-keto-prostaglandin F_1α (6-keto-PGF_1α), thromboxane B₂ (TxB₂), protein, albumin, total cell count, and elastase-α1-proteinase-inhibitor complex in BAL fluid of 18 CDH patients and of 13 control subjects without PPH. We found different concentrations of prostanoids in BAL fluid of CDH patients with PPH: infants with a poor prognosis had either high levels of both 6-keto-PGF_1α and TxB₂ compared to controls, or high levels of 6-keto-PGF_1α only. TxB₂ levels showed a large variability in all CDH patients irrespective of outcome. We conclude that prostanoid levels in BAL fluid do not predict clinical outcome in CDH patients.

Lung eicosanoids in perinatal rats with congenital diaphragmatic hernia

Abnormal levels of pulmonary eicosanoids have been reported in infants with persistent pulmonary hypertension (PPH) and congenital diaphragmatic hernia (CDH). We hypothesized that a dysbalance of vasoconstrictive and vasodilatory eicosanoids is involved in PPH in CDH patients. The levels of several eicosanoids in lung homogenates and in bronchoalveolar lavage fluid of controls and rats with CDH were measured after caesarean section or spontaneous birth. In controls the concentration of the stable metabolite of prostacyclin (6-keto-PGF_1α), thromboxane A₂ (TxB₂), prostaglandin E₂ (PGE₂), and leukotriene B₄ (LTB₄) decreased after spontaneous birth. CDH pups showed respiratory insufficiency directly after birth. Their lungs had higher levels of 6- keto-PGF_1α, reflecting the pulmonary vasodilator prostacyclin (PGI₂), than those of controls. We conclude that in CDH abnormal lung eicosanoid levels are present perinatally. The elevated levels of 6-keto-PGF_1α in CDH may reflect a compensation mechanism for increased vascular resistance.

The effect of ozone exposure on the release of eicosanoids in guinea-pig BAL fluid in relation to cellular damage and inflammation

The observed effects after ozone exposure strongly depend on ozone concentration and exposure time. We hypothesized that depending on the O3 exposure protocol, mainly either an oxidant damage or an inflammation will determine the O3 toxicity. We compared two different ozone exposure protocols: an acute exposure (3 ppm 2 h) for studying the oxidant damage and an exposure (1 ppm 12 h) where an inflammatory component is also probably involved. We measured LDH activity and protein and albumin exudation as markers for cellular damage. After the acute exposure an increase in LDH activity was measured and after exposure to 1 ppm ozone for 12 h the exudation of protein and albumin was also enhanced. The histological examinations showed a neutrophilic inflammatory response only after exposure to 1 ppm ozone for 12 h. The acute exposure protocol resulted in an increased release of PGE2, PGD2, PGF2alpha and 6-ketoPGF1alpha whereas exposure to 1 ppm ozone for 12 h led to an additional release of LTB4. No effects were measured on the release of TxB2 and LTC4/D4/E4. These changed amounts of eicosanoids will probably contribute to the ozone-induced lung function changes.

Diagnostic criteria in patients with complex regional pain syndrome assessed in an out-patient clinic

BACKGROUND

Specific criteria have been described and accepted worldwide for diagnosing patients with complex regional pain syndrome (CRPS). Nevertheless, a clear-cut diagnosis cannot be confirmed in a number of cases.

AIM

The objective of this study was to investigate the effectiveness of the described diagnostic criteria used by several clinical disciplines.

METHODS

We included 195 patients who were referred to our pain clinic within a period of 1 year. Data were collected on patient characteristics, signs, symptoms, disease-related medication, and the background of the referring clinicians.

RESULTS

The Harden and Bruehl criteria were confirmed in 95 patients (49%). These patients used a higher than average number of analgesics, opiates, and anti-oxidants, and frequently received prescriptions for benzodiazepines instead of anti-depressants. The mean disease duration was 29 +/- 4.6 months and the mean visual analogue score for pain was 8.1 +/- 0.19. A subgroup of patients had a colder temperature in the affected extremity compared with the unaffected extremity. This subgroup showed a longer disease duration and higher visual analogue scale pain.

CONCLUSION

The diagnostic criteria used to determine CRPS should be further improved. A large number of referred patients experienced substantial pain, without receiving adequate medication. Disease-related medication is unrelated to CRPS-specific disease activity. Knowledge of underlying mechanisms is warranted before an adequate pharmaceutical intervention can be considered.

Increased plasma glutamate, glycine, and arginine levels in complex regional pain syndrome type 1

BACKGROUND

Various inflammatory mediators have been identified as potential contributors to complex regional pain syndrome type 1 (CRPS1), but these mediators do not entirely explain certain manifestations of the syndrome, such as pain. The objective of this study was to investigate the role of amino acids in the pathogenesis of CRPS1.

METHODS

We used HPLC to determine plasma concentrations of 16 amino acids, especially those related to the NMDA receptor (e.g., glutamate and glycine) and nitric oxide (NO) synthesis (e.g., arginine and citrulline) in patients with CRPS1 (n=64) and age- and sex-matched healthy controls (n=51). Patients rated pain intensity (visual analog scale) and the subjective experience of pain intensity (McGill Pain Questionnaire). Psychological dysfunction was assessed using the SCL-90.

RESULTS

Relative to controls, in CRPS1 patients, plasma levels of glutamate, arginine, taurine, and glycine were increased, and plasma levels of glutamine and the ratio of citrulline to arginine were decreased. Remarkably, in CRPS1 patients there was a highly significant inverse correlation between glutamine and glutamate, although the sum of molar concentrations of glutamate and glutamine remains unchanged. Subjective measures of pain and indicators of psychoneuroticism and emotional instability did not correlate with amino acid levels.

CONCLUSION

This study shows for the first time a pronounced increase in amino acid levels in this chronic pain syndrome. The marked differences in glutamate, glutamine, glycine, taurine and arginine levels between patients and controls suggest the involvement of both the NDMA receptor and the endothelium-dependent arginine-NO system in CRPS1.

Interleukin-2-Deficient mice: effect on cytokines and inflammatory cells in chronic colonic disease

Mice deficient in interleukin-2 (IL-2-/-) develop inflammatory bowel disease resembling human ulcerative colitis. After death, macroscopic and microscopic scores were used to determine colonic inflammation. Both scores were significantly increased in the colon of IL-2-/- mice as compared to wild types mice. The level of IL-1beta 24-week-old was increased in IL-2-/- mice produced by the colon as compared with IL-2+/+ controls. However, the concentrations of IL-6 and IL-10 were not changed. The spleen weight of IL-2-/- mice was significantly increased compared with IL-2+/+ controls. We used immunochemical techniques in low-temperature paraffin-embedded spleen of IL-2-/- mice to examine pathological changes of CD4+ T cells, CD8' T cells, and CD11b+ cells. The tissue was successfully stained and was well preserved. The percentage CD4+ T cells was not significantly changed, while the percentage CD8+ T cells was significantly decreased in IL-2-/- mice compared with IL-2+/+ controls. On the other hand, the percentage CD11b+ cells was significantly increased in the spleen of IL-2-/- mice compared with IL-2+/- controls. As well as the marked difference in CD8+ and CD11b+ cells in the spleen, the increased level of IL-1beta in colonic tissue might indicate that cytotoxic T cells as well as macrophages are involved in the development and/or perpetuation of the inflammatory reactions in IL-2-/- mice.

Neuroimmune alterations in the complex regional pain syndrome

This review focuses on some clinical aspects of the complex regional pain syndrome, such as oedema, local temperature changes and chronic pain, as a result of supposed neurogenic inflammation. Involvement of the immune system could imply the subsequent release of neuropeptides, pro-inflammatory cytokines and eicosanoids, which in turn leads to a complex cross-talk of primary and secondary generated mediators of inflammation. The development and application of drugs that act through selective receptor antagonism or enzymatic synthesis inhibition to prevent further stimulation of this cascade that could inevitably lead to chronicity of this disease are extensively discussed.

Ridogrel enemas in distal ulcerative colitis

OBJECTIVE

To evaluate the effect of Ridogrel enemas (Janssen Research Foundation, Beerse, Belgium) on disease activity and mucosal inflammatory mediators in patients with active left-sided ulcerative colitis.

DESIGN AND METHODS

Eleven patients with active left-sided ulcerative colitis were evaluated in an open non-placebo-controlled pilot study. All patients were treated with Ridogrel enemas (300 mg/40 ml once daily) over four weeks. A disease activity score based on clinical, endoscopic and histological criteria was obtained before and after treatment with Ridogrel. The concentrations of thromboxane B2 (TxB2), prostaglandin E2 (PGE2), interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) were measured in mucosal biopsies before and after treatment.

RESULTS

One patient discontinued treatment because of progression of disease, the other ten patients tolerated the Ridogrel enemas well. Mucosal TxB2 concentration decreased significantly in all patients. The mucosal concentrations of the other inflammatory mediators (PGE2, IL-6 and TNF-alpha) were unaltered. The disease score decreased in five patients. However, clinical improvement was not always associated with a decrease in endoscopic and/or histological scores.

CONCLUSIONS

This pilot study shows that Ridogrel enemas selectively reduce mucosal TxB2 concentration.

Effects of fluticasone propionate inhalation on levels of arachidonic acid metabolites in patients with chronic obstructive pulmonary disease

BACKGROUND

In smoking COPD patients the bronchoalveolar lavage (BAL) fluid contains high numbers of inflammatory cells. These cells might produce arachidonic acid (AA) metabolites, which contribute to inflammation and an increased bronchomotor tone.

AIMS

To investigate levels of AA metabolites in BAL fluid, before and after inhaled glucocorticoid therapy: fluticasone propionate (FP) 1 mg per day, or placebo.

METHODS

A double-blind placebo controlled trial lasting six months. COPD patients were selected by clinical criteria and the presence of bronchial hyper-responsiveness (BHR). Lung function was recorded and in BAL fluid we counted cell numbers and measured LTB4, LTC4/D4/E4, PGE2, 6kPGF1alpha, PGF2alpha and TxB2. A control group consisted of asymptomatic smokers (n=6).

RESULTS

Paired data were obtained from 9 FP treated and 11 placebo patients. BAL cells were almost exclusively alveolar macrophages. In patients and controls both cellularity and levels of AA metabolites were equal Cell numbers did not change after treatment. Statistically significant decreases after FP therapy were noticed for PGE2 (30%), 6kPGF1alpha (41%) and PGF2alpha (54%).

CONCLUSIONS

In COPD, the capability of inflammatory cells to produce certain AA metabolites was decreased after inhaled FP treatment. This result is discussed in its relation to clinical effects, the influence of smoking, and the results of an earlier, similar study in asthma patients.

The effect of dexamethasone treatment on murine colitis

BACKGROUND

Corticosteroids are used as anti-inflammatory drugs in the treatment of inflammatory bowel disease. We wanted to know whether dexamethasone (DEX) treatment could prevent dextran sulphate sodium (DSS)-induced colitis in mice.

METHODS

Acute colitis was induced after oral administration of 10% DSS for 2 days. Controls received normal tap water. Five days before and during DSS or tap water exposure half the group was treated with 0.06 mg/day DEX, and the other half received saline. After the mice had been killed, macroscopic observation and histologic evaluation were used to determine the degree of colonic inflammation.

RESULTS

The macroscopic score was significantly increased in untreated DSS mice (P < 0.001). The induction of colitis was not prevented by DEX pretreatment (5.9 +/- 0.9 versus 4.2 +/- 0.6; NS). In addition, the macroscopic scores of DEX-treated controls were significantly increased (1.8 +/- 0.2 versus 0.7 +/- 0.2; P = 0.007), which suggests that DEX has a stimulating effect on colitis induction. The histology score was significantly increased in untreated DSS mice compared with controls (P = 0.016). Analogous to the macroscopic scoring results, the histology score of DEX-treated controls was significantly increased compared with untreated controls (P = 0.046).

CONCLUSIONS

Pretreatment with dexamethasone did not prevent the induction of acute DSS colitis, reflected by both aggravated macroscopic and histologic inflammation scores.

Time dependent production of cytokines and eicosanoids by human monocytic leukaemia U937 cells; effects of glucocorticosteroids

In the present study the human monoblast cell line U937 has been used as a model to study the function of human mononuclear phagocytes in asthma. The kinetics of the production of eicosanoids and cytokines, which are thought to play a role in the pathogenesis of asthma, were studied. In addition, the effects of glucocorticosteroids were investigated, as these drugs are of great importance for the treatment of asthmatic patients. After stimulation with phorbol-12 myristate acetate (PMA) for 24 h, U937 cells were cultured in the absence or presence of lipopolysaccharide (LPS: 1 and 5 microg ml(-1)) and glucocorticosteroids (budesonide, fluticasone propionate and prednisolone: 10(-11), 10(-9) and 10(-7) M) for 96 h. The production of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) gradually increased in time after stimulation with LPS, whereas the transient production of tumor necrosis factor alpha (TNF-alpha) reached its maximum between 6 and 12 h. Interferon-gamma (IFN-gamma), interleukin-10 (IL-10) and leukotriene B4 (LTB4) were not detectable. All three glucocorticosteroids (budesonide, fluticasone propionate and prednisolone) completely inhibited the production of both eicosanoids and cytokines. The production of eicosanoids was more sensitive to these glucocorticoids than the production of cytokines. The observed differences in the kinetics of the production of eicosanoids and cytokines stress the importance of time course experiments in studies on the effect of drugs on mononuclear cells.

Transdermal nicotine inhibits interleukin 2 synthesis by mononuclear cells derived from healthy volunteers

BACKGROUND

Smoking has either a beneficial or harmful effect on the course and recurrence of ulcerative colitis (UC) and Crohn's disease respectively. Transdermal application of nicotine had similar effects in UC and therefore was considered to be an effective basic drug that could be further developed in the search for new compounds in the treatment of acute exacerbations of corticosteroid-resistant UC. To clarify the hypothesis that nicotine exerts its anti-inflammatory effect in UC through selective inhibition of T-cell-derived cytokine synthesis, we studied in vivo effects of nicotine on cytokine production by human non-adherent mononuclear cells isolated from peripheral blood in a randomized, double-blind, placebo-controlled trial.

METHODS

Healthy non-smoking volunteers applied for 2 weeks of nicotine patches (n = 12) with incremental doses of nicotine during the first week to achieve a maintenance dose of 15 mg per day, or placebo (n = 12). Blood was obtained before treatment and 1, 2, 3 and 6 weeks after the start of treatment. Cells were cultured in the absence or presence of phytohaemagglutinin for 48 h, and total amounts of interleukin 2 (IL-2), IL-4, IL-10, IL-13, interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha) were measured.

RESULTS

Transdermal nicotine caused a significant inhibition of IL-2 after 2 weeks' treatment compared with the placebo group. In addition, a diminished production of IL-10 and TNF-alpha in comparison with day 0 was observed.

CONCLUSION

The beneficial effect of transdermal nicotine in ulcerative colitis may be mediated by a selective inhibition of the IL-2 production by mucosal mononuclear cells, which could result in diminished cell proliferation and consequently a reduction in the inflammatory process.

Smoking and nicotine in inflammatory bowel disease: good or bad for cytokines?

Smoking has either a beneficial or harmful effect on the course and recurrence of ulcerative colitis and Crohn's disease respectively. Transdermal application of nicotine had similar effects in ulcerative colitis and therefore was considered to be an effective basic drug which could be further developed in the search for new compounds in the treatment of acute exacerbations of corticosteroid resistant ulcerative colitis. In this communication the short-term use of nicotine in ulcerative colitis is reviewed.

Diminished nitroprusside-induced relaxation of inflamed colonic smooth muscle in mice

The dextran sodium sulphate (DSS) induced colitis in mice was used as a experimental model to study the contractility of murine longitudinal colonic smooth muscle during inflammation. Smooth muscle segments of proximal, middle and distal colon were mounted in organ baths. Smooth muscle contraction was induced by carbachol showing an aboral increase in activity, whereas in the inflamed middle colonic segment a marked decrease in activity was observed. The dilatative effect of sodium-nitroprusside (SNP) as a nitric oxide donor was investigated after precontraction by carbachol. Both in normal and DSS segments administration of SNP to isolated mouse colonic smooth muscle preparations caused regional differences in relaxation, the highest relaxation seen in normal proximal colonic tissue. However, this relaxation was markedly reduced in inflamed proximal preparations, associated with a diminished cGMP contents.

Intestinal permeability and contractility in murine colitis

We developed an in vitro organ bath method to measure permeability and contractility simultaneously in murine intestinal segments. To investigate whether permeability and contractility are correlated and influenced by mucosal damage owing to inflammation, BALB/c mice were exposed to a 10% dextran sulphate sodium (DSS) solution for 8 days to induce colitis. The effect of pharmacologically induced smooth muscle relaxation and contraction on permeability was tested in vitro. Regional permeability differences were observed in both control and 10% DSS-treated mice. Distal colon segments were less permeable to 3H-mannitol and 14C-PEG 400 molecules compared with proximal colon and ileum. Intestinal permeability in control vs. 10% DSS mice was not altered, although histologic inflammation score and IFN-gamma pro-inflammatory cytokine levels were significantly increased in proximal and distal colon. IL-1beta levels were enhanced in these proximal and distal segments, but not significantly different from controls. Any effect of pharmacologically induced contractility on intestinal permeability could not be observed. In conclusion, intestinal permeability and contractility are not correlated in this model of experimentally induced colitis in mice. Although simultaneous measurement in a physiological set-up is possible, this method has to be further validated.

The role of prostanoids in ozone-induced changes in airway responsiveness: receptor activation-specific prostanoid release

We studied the effect of in vivo ozone exposure (3 ppm, 2 h) on methacholine- and histamine-induced guinea pig tracheal smooth muscle contractions in vitro and the role of cyclooxygenase products in this process. After exposure to ozone, methacholine stimulation showed a functional hyperreactivity, whereas after stimulation with histamine a hyporeactivity was observed. These effects could be explained by the release of prostanoids. In a control situation an increase in PGF(2α), PGE(2) and PGD(2) release is observed after stimulation of the histaminergic receptor system. After ozone exposure the release of prostanoids was also enhanced (unstimulated, PGF(2α) and TxB(2); histamine, PGF(2α), PGE(2); methacholine, PGF(2α), TxB(2), 6-kPGF(1α), PGE(2)). This study shows that the prostanoid release is strongly dependent on the receptor system stimulated to induce smooth muscle contraction and the importance of prostanoids in ozone-induced changes in guinea pig tracheal smooth muscle reactivity.

Somatostatin does not attenuate intestinal injury in dextran sodium sulphate-induced subacute colitis

FRom several in vitro and in vivo studies involvement of somatostatin (SMS) in intestinal inflammation emerge. Acute colitis induced in rats is attenuated by the long-acting SMS analogue octreotide. We studied the potential beneficial effect of SMS on non-acute experimental colitis. BALB/c mice received either saline, SMS-14 (36 or 120 microg daily) or octreotide (3 microg daily) subcutaneously delivered by implant osmotic pumps. A non-acute colitis was induced by administration of dextran sodium sulphate (DSS) 10% in drinking water during 7 days. DSS evoked a mild, superficial pancolitis, most characterized by mucosal ulceration and submucosal influx of neutrophils. Neither SMS-14 nor octreotide reduced mucosal inflammatory score or macroscopical disease activity, although reduction of intestinal levels of interleukin-1beta (IL-1beta), IL-6 and IL-10 during DSS was augmented both by SMS and octreotide. A slight increase of neutrophil influx was seen during SMS administration in animals not exposed to DSS. In conclusion, SMS or its long-acting analogue did not reduce intestinal inflammation in non-acute DSS-induced colitis. According to the cytokine profile observed, SMS-14 and octreotide further diminished the reduction of intestinal macrophage and Th2 lymphocyte activity.

Excessive prolongation of the bleeding time by aspirin in essential thrombocythemia is related to a decrease of large von Willebrand factor multimers in plasma

Patients with essential thrombocythemia (ET), who frequently have bleeding complications, may manifest an excessive prolongation of the bleeding time (BT) after ingestion of aspirin (ASA). The reason for this excessive prolongation of the BT is unknown, but it is attributed to qualitative platelet defects. Since patients with ET may also have acquired abnormalities of plasma and platelet von Willebrand factor (vWF), we questioned whether the excessive prolongation of the BT by ASA was related to changes in either plasma or platelet vWF. To that end, we studied BT and plasma and platelet vWF in ten ET patients, ten patients with reactive thrombocytosis (RT), and ten normal individuals, both before and after administration of 500 mg ASA for 7 days. In a second study, the effect of DDAVP infusion on plasma vWF in relation to the BT was studied in ten normal individuals and ten ET patients after treatment with 100 mg ASA for 3 days. In the first study, treatment with ASA resulted in a significant prolongation of the BT in normal subjects, RT patients, and ET patients. However, in five ET patients an excessive (> 2 SD) prolongation of the BT by ASA was observed. Although ASA induced no direct changes in either plasma or platelet vWF levels in either normal subjects, RT patients, or ET patients, all five ET patients who showed an excessive prolongation of the BT by ASA had significantly decreased levels of large vWF multimers in plasma. In the second study, infusion with DDAVP resulted in a significant increase in plasma large vWF multimers, paralleled by a normalization of (excessively) prolonged BT. Our data suggest that in ET inhibition of platelet function by ASA in the presence of concurrently decreased levels of large vWF multimers in plasma may have provoked the excessive BT prolongation.

Response to intranasal fluticasone propionate in perennial allergic rhinitis not associated with glucocorticoid receptor characteristics

BACKGROUND

The reduction of symptoms due to treatment with corticosteroids varies among patients with perennial rhinitis. Most patients will respond but a few patients respond less to these drugs.

OBJECTIVE

To investigate the association in reduction of symptoms due to glucocorticoids and glucocorticoid receptor characteristics in patients with perennial allergic rhinitis, in vitro glucocorticoid receptor binding studies were performed with peripheral blood mononuclear cells using dexamethasone and in vitro production of mediators were measured.

METHODS

During a double-blind placebo-controlled crossover study, 200 micrograms fluticasone propionate aqueous nasal spray (in the active treatment period) and placebo (in the placebo treatment period) were administered twice daily for 2 weeks to 22 patients allergic to house dust mite. At the end of both treatment periods symptoms were scored after allergen provocation (100, 1000, 10000 BU/mL) and during the 9.5 hours after this challenge. Receptor binding studies with dexamethasone were performed with peripheral blood mononuclear cells. Leukotriene B4 produced by monocytes in vitro and soluble interleukin-2 receptor released by lymphocytes in vitro and cortisol levels in plasma were determined.

RESULTS

No significant partial correlations of the number of the peripheral blood mononuclear cell glucocorticoid receptors (6821 +/- 5669 binding sites per cell) and the affinity (Kd: 16.5 +/- 13.51 nmol/L) for the glucocorticoid receptors with the symptom score (placebo: 4.3 +/- 2.45 pts; fluticasone: 2.4 +/- 1.55 pts) after active treatment were found. Also no significant partial correlations of the levels of leukotriene B4 (45.6 +/- 105.3 ng/10(6) cells) produced by monocytes in vitro, soluble interleukin-2 receptor (734 +/- 237 ng/10(6) cells) released by lymphocytes in vitro and cortisol levels (571 +/- 236 ng/mL) in plasma with the symptom score after active treatment were found.

CONCLUSIONS

The reduction of symptoms due to topical fluticasone propionate in patients with rhinitis and allergy to house dust mite is not correlated with the characteristics of the glucocorticoid receptor.

Effect of nicotine on large bowel mucus thickness, eicosanoids and faecal proteinase in ferrets

BACKGROUND

Following observations on the effect of subcutaneous nicotine on rectal mucosal eicosanoids and mucus in the rabbit we have repeated the work in ferrets which may be a more suitable animal model.

AIMS AND METHODS

The effect of nicotine on mucosal eicosanoids, the adherent mucus layer, and faecal proteinases in the large bowel of ferrets was examined in forty animals randomly allocated to five groups, a control and four treatment groups. They were given subcutaneous saline or nicotine via an Alzet pump in doses of 0.3, 0.6, 1.2 and 2.0 mg/kg/day for 10 days and then sacrificed; measurements were made of serum nicotine and cotinine levels, rectal mucosal eicosanoids, adherent rectal and colonic mucus thickness, and faecal proteinases.

RESULTS

No significant differences were observed for any measurements, except for serum nicotine and cotinine levels, which were raised consistent with the dose given.

CONCLUSION

Nicotine had no effect on measurements, which may possibly be important in the relationship between smoking and ulcerative colitis.

Endogenously produced prostanoids stimulate calcium reabsorption in the rabbit cortical collecting system

1. The influence of endogenously produced prostanoids on active transepithelial Ca2+ transport and cAMP formation was investigated in immunodissected rabbit kidney connecting and cortical collecting tubule cells grown to confluency on permeable supports. 2. The cyclo-oxygenase inhibitor indomethacin dose-dependently (IC50 = 18 nM) reduced the net apical-to-basolateral Ca2+ transport by 57%. Inhibition was reversed in medium obtained from monolayers incubated in the absence of indomethacin. 3. HPLC analysis following incubation with 14C-labelled arachidonic acid revealed the presence of a wide variety of radiolabelled prostanoids in both the apical and basolateral media. These findings are compatible with the endogenous production and subsequent release of stimulatory prostanoids. 4. The inhibitory action of indomethacin was reversed by the addition of the prostanoids PGE1, PGE2 and PGA2, but not PGD2, PGF2 alpha, the stable PGI2 analogue cicaprost or the thromboxane A2 mimetic U-46619. PGE2 stimulated transepithelial Ca2+ transport dose dependently (EC50 = 3 nM), irrespective of the compartment of which it was added. The stimulatory effect of PGE2 was paralleled by increased cAMP formation, suggesting the apical and basolateral presence of stimulatory prostanoid receptors EP2 and/or EP4. 5. Sulprostone, an analogue selective for EP1 and EP3 receptors, inhibited transepithelial Ca2+ transport in indomethacin-treated monolayers only when applied basolaterally, suggesting the exclusive presence of inhibitory EP receptors on the basolateral membrane. 6. The percentage by which parathyroid hormone and arginine vasopressin increased both transepithelial Ca2+ transport and cAMP formation was dramatically increased in indomethacin-inhibited cells as compared with control cells, demonstrating that indomethacin unmasks the actions of these hormones to their full extent.

Augmented contraction of the human isolated coronary artery by sumatriptan: a possible role for endogenous thromboxane

1. The antimigraine drug, sumatriptan, contracts the human coronary artery and, in some patients, elicits chest symptoms (e.g. pressure and pain), particularly after subcutaneous administration. We studied the effects of the thromboxane A2 (TxA2) analogue, U46619 and endothelin-1 on contractile responses to sumatriptan in the human isolated coronary artery as well as the role of endogenously produced TxA2 and endothelin-1 in contractions evoked by sumatriptan. 2. In the presence of U46619 (1 and 3 nM), mean concentration-response curves to sumatriptan in the human coronary artery were shifted vertically due to the initial contraction by U46619, but when this initial contraction was subtracted from the response to sumatriptan, no significant augmentation was observed. However, analysis of the degree of augmentation in individual arterial segments revealed that the augmentation was variable and related inversely to the Emax of sumatriptan in the absence of U46619 (r = 0.78 and 0.81 for 1 and 3 nM, respectively; P < 0.05). 3. Treatment with the TxA2 receptor antagonist, SQ30741 (100 nM), or incubation of vessel segments with aspirin (10 microM), significantly reduced responses to sumatriptan; in aspirin-treated vessel segments, SQ30741 failed to decrease further the contractions to sumatriptan. The decrease in Emax of sumatriptan by both SQ30741 and aspirin correlated significantly with the Emax of sumatriptan without SQ30741 (r = 0.74; P < 0.01) or aspirin (r = 0.94; P < 0.01). In aspirin-treated vessel segments, responses to sumatriptan were significantly augmented in the presence of U46619 (3 nM; P < 0.05). 4. The specificity of SQ30741 was demonstrated by its ability to antagonize coronary artery contractions to U46619 (pA2: 7.54 +/- 0.30), but not endothelin-1. Similarly, incubation with aspirin (10 microM) did not affect contractile responses to endothelin-1, but significantly reduced TxA2 production in coronary artery segments as judged by a decrease in thromboxane B2 (TxB2) from 4.77 +/- 0.98 to 1.38 +/- 0.36 ng g-1 2 h-1. 5. Endothelin-1 (1 nM) did not significantly augment contractions to sumatriptan; there was also no relationship between the degree of augmentation and the control Emax of sumatriptan in the absence of endothelin-1. Furthermore, unlike SQ30741 or aspirin, a high concentration (100 nM) of the non-selective ETA/ETB receptor antagonist, SB 209670, failed to affect contractile responses to sumatriptan. However, SB 209670 potently antagonized coronary artery contractions induced by endothelin-1 with a pA2 of 8.84 +/- 0.32. 6. Compared to control vascular segments, endothelial denudation did not reduce TxA2 production (with endothelium = 2.56 +/- 1.38 vs. without endothelium = 12.32 +/- 4.94 ng TxB2 g-1 2 h-1), suggesting that the production of TxA2 is not confined to the endothelium. The sumatriptan-induced contractions were also unaffected by endothelial denudation. 7. The results of the present study suggest that endogenously produced TxA2 enhances contractions to sumatriptan in the human isolated coronary artery. Such a mechanism may play a role in causing chest symptoms after sumatriptan by potentiating coronary vascular contraction by sumatriptan in vivo.

Nicotine inhibits the in vitro production of interleukin 2 and tumour necrosis factor-alpha by human mononuclear cells

Smoking protects against ulcerative colitis (UC), and treatment with nicotine patches has a beneficial symptomatic effect in patients with UC. To find an explanation for this response to nicotine in UC, we assessed the effects of nicotine on cytokine production by mononuclear cells (MNC). MNC were isolated from peripheral blood from healthy volunteers. Non-adherent MNC were preincubated with varying concentrations of nicotine or prednisolone for 24 h followed by addition of phytohemagglutinin (10 micrograms/ml). The concentrations of interleukin 2 (IL-2) and tumour necrosis factor-alpha (TNF alpha) in the supernatants were determined by ELISA. Nicotine as well as prednisolone caused a significant inhibition of IL-2 and TNF alpha production. The maximum inhibition caused by nicotine was about 50% of that caused by prednisolone and was reached at concentrations equivalent to nicotine levels measured in plasma of smokers. These results indicate that nicotine exerts its immunoregulatory role through modulation of the cytokine production by non-adherent mononuclear cells.

In-vivo effect of nicotine on cytokine production by human non-adherent mononuclear cells

OBJECTIVE

Ulcerative colitis (UC) is predominantly a disease of non-smokers and treatment with transdermal nicotine improves symptoms in UC patients, whereas smoking seems to have a deleterious effect in patients with Crohn's disease (CD). In CD the cytokine profile is of a dominant TH1 (T helper 1) pattern whereas in UC the TH2 pattern predominates. To find an explanation for the beneficial effect of nicotine in UC and the deteriorative effect in CD we studied the in-vivo effect of nicotine on the interleukin 2 (IL-2), IL-10 and tumour necrosis factor alpha (TNF alpha) production by human cells.

DESIGN

Eleven healthy male non-smokers were included in this study. The volunteers applied nicotine patches with a regulated release of 5 mg (day 1 and 2), 10 mg (day 3 and 4) and 15 mg (day 5, 6 and 7) nicotine per day.

METHODS

Heart rate and blood pressure were recorded, nicotine and cotinine concentrations in plasma measured before and after 2, 4 and 7 days of treatment. Non-adherent mononuclear cells (NAC) were isolated from peripheral blood obtained from the subjects before and after 7 days of treatment. The NAC were cultured in the absence or presence of phytohemagglutinin for 48 h. Total amount of IL-2, IL-10 and TNF alpha formed were measured in the supernatants using specific ELISAs.

RESULTS

Treatment with nicotine caused a significant inhibition of IL-10 production by NAC. In contrast, nicotine patch treatment had no effect on the production of IL-2 and TNF alpha.

CONCLUSIONS

Nicotine in vivo has an inhibitory effect on TH2 cell function as measured by inhibition of IL-10 production, but does not appear to have any effect on TH1 cell function.

Eicosanoids and lipocortin-1 in BAL fluid in asthma: effects of smoking and inhaled glucocorticoids

Both smoking and asthma are associated with inflammatory changes in the lung, which may be suppressed with the help of exogenous anti-inflammatory drugs or by the endogenous defense system. Lipocortin-1 (LC-1; annexin-1) is an anti-inflammatory protein present in respiratory tract secretions. We report an inverse correlation between extracellular LC-1 concentration and the bronchoconstrictor prostaglandin (PG) D2 [n = 15, Spearman rank correlation coefficient (rS) = -0.597, P < 0.05] in bronchoalveolar lavage fluid (BALF) from allergic asthmatic patients, together with positive correlations between extracellular LC-1 per milliliter BALF and the prostacyclin (PGI2) metabolite 6-keto-PGF1 alpha (n = 15, rS = 0.480, P < 0.05) and between LC-1 per milliliter BALF and concentration of histamine causing a 20% decrease in forced expired volume in 1 s (n = 15, rS = 0.720, P < 0.01) in these subjects. We found no significant difference between the LC-1 concentration in BALF from nonsmoking asthmatic patients who were receiving inhaled glucocorticoid therapy (2 x 100 micrograms beclomethasone 4 times/day for 2.5 yr; median 186 ng LC-1/mg albumin; n = 6) and those who were not (median 126 ng LC-1/mg albumin; n = 12), perhaps because inhaled drugs deposit predominantly in central airways, which are poorly represented in bronchoalveolar lavage. Both asthmatic and healthy volunteers who smoked had higher levels of LC-1 in their BALF than did their nonsmoking counterparts (e.g., asthmatic smokers, median 317 ng LC-1/mg albumin, n = 10; asthmatic nonsmokers, median 162 ng LC-1/mg albumin, n = 18; P < 0.05), perhaps because smokers' lungs contain more alveolar macrophages, cells that release LC-1. We observed a positive correlation between BALF LC-1 and bronchoalveolar lavage cell number (n = 16, rS = 0.821, P < 0.001). Increased extracellular LC-1 may be part of a protective response of the lung to inflammatory insult. Regulation of prostanoid levels might be one mechanism by which LC-1 suppresses inflammation.

Selective effect of levocabastine on histamine receptor and histamine release from human leukocytes and guinea pig isolated tissue

BACKGROUND

Levocabastine is a potent histamine H1 receptor antagonist used topically in the treatment of patients with allergic rhinitis. It has been suggested that antihistamines also have anti-inflammatory properties.

OBJECTIVE

The present study was performed to investigate whether levocabastine, in addition to the anti-H1 receptor activity, has anti-inflammatory properties and thus is able to modulate the release of histamine and cytokines, such as interleukin 5 from human leukocytes and isolated tissues.

METHODS

Leukocytes suspensions were prepared by dextran sedimentation of peripheral venous blood drawn from allergic and healthy volunteers. Leukocytes obtained from allergic volunteers were preincubated for 30 minutes with levocabastine (doses 10(-8) M to 10(-6) M) and thereafter incubated with allergen. Leukocytes obtained from healthy volunteers were incubated for zero to three hours with levocabastine (doses 10(-14) M to 10(-3) M). Histamine release was measured by an automated fluorometric method. Interleukin-5 release was measured by enzyme linked immunoassay. Contractile responses to histamine on guinea pig trachea and lung parenchyma as well as the release of histamine and interleukin-5 by the tissues were investigated in the absence or presence of levocabastine and/or the histamine H2 receptor antagonist cimetidine.

RESULTS

Levocabastine did not influence allergen-induced histamine release from leukocytes obtained from allergic volunteers. High concentrations (10(-4)and 10(-3) M) of levocabastine, however, caused release of histamine from leukocytes obtained from healthy volunteers as well as guinea pig airway smooth muscle tissues. Pretreatment with levocabastine dose-dependently decreased the contractile response to histamine, showing an irreversible competitive mechanism. Interleukin 5 release from human leukocytes and by guinea pig airway smooth muscle was not detectable.

CONCLUSIONS

These findings indicate that the H1 receptor blocker, levocabastine, has probably no anti-inflammatory properties, measured as histamine release, and that the histamine release from both human leukocytes and guinea pig trachea and lung parenchyma is significantly increased by the drug only at high concentrations.

Eicosanoid and amino acid metabolism in transient acute psychoses with psychedelic symptoms

It has been hypothesized that a disturbance of glutathione (GSH) metabolism might be a common factor in many psychiatric disorders. The aim of the present study was to test this hypothesis in transient acute psychotic patients with distorted perceptions. Since the metabolism of GSH is related to that of thromboxane B2 (TXB2), prostaglandin E (PGE) and some amino acids, we determined these substances in the plasma of 15 patients and 17 normal controls. Plasma concentrations of TXB2 were significantly higher and concentrations of serine and tryptophan were significantly lower in patients than in controls. Large variation was observed in plasma PGE levels in patients, although mean values did not differ significantly from controls. These results are consistent with the hypothesis that the metabolism of GSH is impaired in transient psychotic states.

Interleukin-1 receptors on rat brain endothelial cells: a role in neuroimmune interaction?

Inflammation following an infection induces a range of nonspecific symptoms of sickness in animals and humans. The cytokine interleukin-1 (IL-1) mediates many of the brain-mediated symptoms of sickness. Binding sites for IL-1 have been found in mouse brain, but not in the brains of rats. This raises questions as to the involvement of these neuronally localized IL-1 binding sites in the induction of sickness symptoms. Based on observations of IL-1 receptor mRNA in close vicinity to the vasculature in the mouse and rat brain, we studied the possibility that endothelial cells in the rat brain exhibit IL-1 receptors to transduce information to the brain. Ligand binding studies reveal that cultured endothelial cells of adult rat brain exhibit specific binding sites for rat IL-1beta. Polymerase chain reaction experiments demonstrated that mRNA of the type I but not that of the type II IL-1 receptor is present in rat brain endothelial cells. Incubation of these endothelial cells with recombinant rat IL-1beta showed a dose-dependent increase in interleukin-6, prostaglandin E(2), and prostacyclin secretion. Intravenous administration of rat IL-1beta to adult rats enhanced prostaglandin E(2) immunoreactivity in endothelial cells of the brain microvasculature. These results indicate that functional type I IL-1 receptors are present on endothelial cells of adult rat brain. We postulate that circulating IL-1 can be translated by brain endothelial cells into other signals such as interleukin-6 or prostaglandins that have access to the brain and induce sickness symptoms.

High interleukin-6 production within the peritoneal cavity in decompensated cirrhosis and malignancy-related ascites

To assess the diagnostic and prognostic value of interleukin-6, interleukin 1 beta, and tumor necrosis factor-alpha assays in plasma and ascites, we measured these cytokines in eight patients with malignancy-related ascites and 32 patients with decompensated cirrhosis. Five patients had an episode of bacterial peritonitis, during which one or more ascitic fluid samples were analyzed. Interleukin-6 and tumor necrosis factor-alpha were not significantly different between the cirrhotic and the malignant groups: ascitic interleukin-6 13,816 +/- 15,314 vs 28,138 +/- 23,403 pg/ml, plasma interleukin-6 542 +/- 719 vs 559 +/- 604 pg/ml; ascitic tumor necrosis factor-alpha 19 +/- 50 vs 12 +/- 31 pg/ml, plasma tumor necrosis factor-alpha 3.4 +/- 8.2 vs 6.1 +/- 13.8 pg/ml. During an episode of bacterial peritonitis there was a significant increase only in ascitic interleukin-6 (133,268 +/- 99,743 pg/ml), which declined after antibiotic treatment. None of the parameters was associated with 6-month survival (11 of the 40 patients died within 6 months). There was a correlation (r = 0.675; p = 0.002) between plasma interleukin-6 levels and the Child-Pugh score in patients with cirrhosis, but not with the etiology of the liver disorder. Plasma interleukin-6 levels correlated with IgA levels (r = 0.649; p = 0.004) but not with C reactive protein, sedimentation rate, fibrinogen, IgM or IgG. These results do suggest that interleukin-6 is produced within the peritoneal cavity in hepatic and malignant ascites. There is a sharp increase in the local production of interleukin-6 during an episode of bacterial peritonitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Inflammatory cell number and mediators in bronchoalveolar lavage fluid and peripheral blood in subjects with asthma with increased nocturnal airways narrowing

BACKGROUND

Increased nocturnal airways narrowing (NAN) in asthma is thought to occur as the result of intensification of inflammatory processes in the airways. In this study we investigated the presence of inflammatory cells and mediators in bronchoalveolar lavage (BAL) fluid and peripheral blood (PB) and assessed their relationship with the occurrence of increased NAN.

METHODS

BAL fluid and PB samples were assessed at 16:00 and 04:00 hours, separated by 7 days or more, in eight nonatopic healthy subjects (group 1) and 17 atopic subjects with asthma who were using inhaled bronchodilators only. The latter subjects were prospectively assigned to groups with and without NAN, as defined by a mean circadian peak expiratory flow variation of less than 15% (group 2) and 15% or more (group 3), respectively.

RESULTS

Significantly higher eosinophil numbers and inflammatory activation products (eosinophil cationic protein, eosinophil-derived neurotoxin, histamine) were found in BAL fluid and PB from subjects with asthma in comparison with control subjects. However, increased NAN was not generally associated with a circadian fluctuation in cell number and inflammatory mediators in BAL fluid and PB. No differences in inflammatory cell numbers existed that distinguished between groups 2 and 3. However, in group 3 significantly higher BAL prostaglandin D2 levels (70 vs 24 pg/ml; range, 28 to 102 vs 11 to 90 pg/ml; p = 0.04) and serum eosinophil cationic protein levels (17.6 vs 16.1 ng/ml; range, 6.3 to 17.5 vs 6.3 to 60.3 ng/ml; p = 0.03) at 16:00 hours were detected compared with group 2.

CONCLUSIONS

Our findings suggest that increased NAN is more likely to occur in subjects with asthma with ongoing increased cellular activation during the day.

Eicosanoid production by rat cerebral endothelial cells: stimulation by lipopolysaccharide, interleukin-1 and interleukin-6

The capacity of rat cerebral endothelial cells (RCEC) to form eicosanoids was determined after incubation with 14C-labelled arachidonic acid. Prostaglandin E2 (PGE2) was the main metabolite formed by RCEC and was responsible for 54% of the total amount of eicosanoids produced. In contrast, in primary cultures of rat aorta endothelial cells, 32% of the amount of prostaglandins was 6-keto-PGF1 alpha). RCEC treated with 50 ng/ml LPS for 24 h responded with an augmented PGE2 synthesis and 6-keto-PGF1 alpha of 3.4-fold and 2.2-fold, respectively. Cultures treated with IL-1 beta (50 ng/ml) for 3 h showed a stimulation of the release of PGE2 and 6-keto-PGF1 alpha of 2.5- and 4.5-fold, respectively, and 2.0-fold and 2.3-fold, respectively, after IL-6 (50 ng/ml) incubation for 3 h. PGE2 is the main eicosanoid formed by RCEC in response to inflammatory agents, suggesting an important role of the cerebral endothelial cells in the transduction of an inflammatory response in the central nervous system.

Nicotine inhibits cytokine synthesis by mouse colonic mucosa

We examined the in vivo effect of nicotine on the synthesis of (pro)inflammatory mediators by mouse colonic mucosa. The synthesis of lipid mediators such as the prostanoids prostaglandin E2, 6-keto-prostaglandin F1 alpha and thromboxane B2, the 5-lipoxygenase products leukotriene B4 and leukotriene C4 and the platelet activating factor was not affected, whereas the synthesis of the pro-inflammatory cytokines interleukin-1 beta and tumor necrosis factor alpha was completely abolished. The beneficial effects of smoking and nicotine in ulcerative colitis could be attributed to this inhibition.

Levels of soluble intercellular adhesion molecule 1, eicosanoids and cytokines in ascites of patients with liver cirrhosis, peritoneal cancer and spontaneous bacterial peritonitis

The levels of the eicosanoids leukotriene B4, prostaglandin E2, prostacycline and thromboxane B2, the cytokines interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha and soluble intercellular adhesion molecule 1 were measured in ascites and plasma samples of patients with liver cirrhosis (53), peritoneal cancer (26) and spontaneous bacterial peritonitis (10) to assess their value as a possible diagnostic and prognostic parameter in the course of the disease. Soluble intercellular adhesion molecule 1, of the eicosanoids prostaglandin E2 and leukotriene B4, and the protein concentration in ascites were all significantly elevated in ascites of patients with peritoneal cancer in comparison to ascites of patients with liver cirrhosis. In ascites of patients with spontaneous bacterial infection interleukin-6 concentration was significantly elevated and the protein concentration was significantly lower in comparison to the other two groups. None of these parameters, however, seems to be of practical use as a diagnostic parameter, as there is an overlap between all the levels of these mediators in ascites of liver cirrhosis, peritoneal cancer and spontaneous bacterial peritonitis group. Soluble intercellular adhesion molecule 1 levels were much higher in plasma than in ascites, in contrast to interleukin-6 levels which were much higher in ascites than in plasma. Soluble intercellular adhesion molecule 1 in ascites correlated with soluble intercellular adhesion molecule 1 in plasma (r = 0.6926, P = 0.0001). Soluble intercellular adhesion molecule 1, interleukin-6 and the number of polymorphonuclear cells in peritoneal fluid correlated during episodes of infection in patients with a peritonitis. For this reason soluble intercellular adhesion molecule 1 and interleukin-6 could be of prognostic value for patients with peritonitis.

Interleukin-5 and eosinophil cationic protein in nasal lavages of rhinitis patients

The production of interleukin-5 and eosinophil cationic protein (ECP) in the nasal cavity was examined in 24 patients with rhinitis who were allergic to the house dust mite. During a double-blind placebo-controlled cross-over study, fluticasone propionate aqueous nasal spray (200 micrograms) was administered twice daily for 2 weeks. After four basal nasal lavages provocation with house dust mite extract was performed and nasal lavages were collected every hour for 9.5 h. Interleukin-5 was present in detectable amounts in nasal lavages from patients allergic to house dust mite. Nasal challenge with house dust mite extract caused immediate nasal symptoms and increased levels of interleukin-5. Between 3.5 and 8.5 h after the challenge symptoms recurred and interleukin-5 levels increased, reflecting a late phase reaction. Eosinophil cationic protein, a marker of activated eosinophils, was released between 6.5 and 9.5 h after challenge. Treatment with fluticasone propionate (as an aqueous nasal spray) significantly decreased the evoked interleukin-5 and ECP levels in the late phase reaction. This response was correlated with an improved symptom score. This could indicate that the number and activity of eosinophils are increased during the late phase allergic reaction, a response that is inhibited by corticosteroids.

Nitric oxide metabolites in nasal lavage fluid of patients with house dust mite allergy

BACKGROUND

The role of nitric oxide in the early and late phase of the allergic process was investigated in patients with allergic rhinitis against house dust mite and the effect of fluticasone propionate aqueous nasal spray was determined.

METHODS

Production of nitric oxide (measured as nitrite+nitrate) in vivo in nasal mucosa was examined in 24 patients with rhinitis allergic to the house dust mite. In a double blind placebo controlled crossover study fluticasone propionate 200 micrograms aqueous nasal spray was administered twice daily for two weeks. In response to provocation with house dust mite extract (after four basal nasal lavages) nasal lavages were performed every hour for 9.5 hours by washing the nose with saline. In addition, a similar lavage protocol was performed in healthy volunteers with or without challenge with phosphate buffered saline.

RESULTS

Nitric oxide is present in nasal lavage fluid in detectable amounts (range 10-50 microM), the level gradually increasing with time in both patients and controls after a decrease during the four basal lavages. Treatment with fluticasone propionate aqueous nasal spray did not affect initial basal production of nitric oxide nor production following provocation with house dust mite extract.

CONCLUSIONS

Production of nitric oxide in nasal mucosa determined in sequential nasal washings is not affected by therapeutic doses of intranasal steroids.

Effects of short- and long-term feeding of L-carnitine and congeners on the production of eicosanoids from rat peritoneal leucocytes

The effect of short- and long-term feeding with L-carnitine, L-acetyl carnitine and L-propionyl carnitine on the production of eicosanoids from in vitro stimulated carrageenan-induced rat peritoneal macrophages was investigated. Both young (4 weeks) and old (18 months) rats were used. A lower number of cells was isolated from the peritonea of treated than control young rats after 4 d feeding, but after 60 d no differences were observed. A similar reduction in cell number was found when old animals were given L-acetyl carnitine or L-propionyl carnitine (acutely) or L-acetyl carnitine or L-carnitine (chronically). Plasma carnitine levels were higher in young rats given carnitine both chronically and acutely. Carnitine derivatives were without effect. In contrast, levels of total carnitine in the plasma of old rats given L-carnitine and L-acetyl carnitine for 4 d and 60 d were higher than in controls. There was no correlation between total plasma carnitine level and effects on prostaglandin, thromboxane and leukotriene B4 (LTB4) production. In young rats the most important changes were observed in relation to the production of prostacyclin (PGI2), measured as 6 keto-prostaglandin F1 alpha. Prostacyclin production was higher in the groups given carnitine or its derivatives. The net result of the changes in PGI2 was that the 6 keto-prostaglandin F1 alpha: thromboxane B2 and the 6-keto-prostaglandin F1 alpha: LTB4 ratios tended to be higher in cells from young animals following short-term feeding with L-carnitine.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions between cytokines and eicosanoids: a study using human peritoneal macrophages

To examine the interactions between the main pro-inflammatory cytokines and eicosanoids produced by human inflammatory cells, human peritoneal macrophages (hp-M phi) were isolated from ascitic fluid of patients with portal hypertension. Interactions between interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor alpha (TNF-alpha), leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) were studied by addition or inhibition of several cytokines and eicosanoids: human recombinant IL-1 beta (hrIL-1 beta) addition, LTB4 addition and 5-lipoxygenase inhibition (6-hydroxy-2-(4-sulfamoylbenzylamino)-4,5,7-trimethylbenzothiaz ole hydrochloride (E6080)), PGE2 addition and cyclooxygenase inhibition (indomethacin). In hp-M phi hrIL-1 beta stimulated the LTB4 production, while the PGE2 production was inhibited. HrIL-1 beta had no significant effect on IL-6 production in hp-M phi. LTB4 did not regulate IL-1 beta and IL-6 production. Increasing PGE2 down regulated the TNF-alpha production, but did not effect the IL-1 beta and IL-6 production.

Production of inflammatory mediators by human macrophages obtained from ascites

Ascites is a readily available source of human macrophages (M phi), which can be used to study M phi functions in vitro. We characterized the mediators of inflammation produced by human peritoneal M phi (hp-M phi) obtained from patients with portal hypertension and ascites. The production of the cytokines interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) was found to be lipopolysaccharide (LPS) concentration dependent (0-10 micrograms/ml) with a maximal production at 10 micrograms/ml and also dependent on the time of exposure to the stimulus (0-36 h). IL-1 beta, IL-6 and TNF-alpha production after LPS administration reached a plateau at 24 h. In vitro stimulation for 24 h with LPS does not influence the eicosanoid production from endogenous arachidonate. 13 min of exposure of the cells to the calcium ionophore A23187 gives a significant increase in eicosanoid production from both exogenous and endogenous arachidonate. The main eicosanoids produced are the 5-lipoxgenase products LTB4 and 5-hydroxyeicosatetraenoic acid (HETE). The increase in production of the other eicosanoids is not significant. The eicosanoid production depends on the stimulus concentration. The optimal A23187 concentration is 1 microM. Oxygen radical production was measured in the M phi by a flowcytometric method. The fluorescence intensity of phorbol 12-myristate 13-acetate stimulated and dihydro-rhodamine 123 loaded hp-M phi increases significantly after 15 min. We conclude that LPS stimulation of hp-M phi from liver disease results in similar production of IL-1 beta, IL-6 and TNF-alpha, but that the profile of the eicosanoid production of these M phi stimulated with LPS and A23187 differs from M phi of other origin and species.

Effect of nicotine on rectal mucus and mucosal eicosanoids

Because ulcerative colitis is largely a disease of non-smokers and nicotine may have a beneficial effect on the disease, the effect of nicotine on rectal mucosa in rabbits was examined. Nicotine was given subcutaneously by an Alzet mini-pump in doses of 0.5, 1.25, and 2 mg/kg/day for 14 days to three groups of eight animals and compared with eight controls. Mean (SD) serum nicotine concentrations (ng/ml) were 3.5 (1.1), 8.8 (2.3), and 16.2 (5.2) respectively in the treated groups. The thickness of adherent mucus on rectal mucosa in controls (median 36 microns) was significantly reduced by low dose (22 microns, p = 0.0011), and increased by high dose nicotine (48 microns, p = 0.035). Incorporation of radioactive glucosamine into papain resistant glycoconjugates was unchanged, indicating that mucin synthesis was unaltered. Prostaglandins (PG) were reduced, in some cases significantly (6-keto PGF1 alpha, PGF2 alpha, and hydroxy-eicosatetraenoic acid), by nicotine, which showed an inverse dose dependence--with greatest inhibition in relation to the lowest dose. Nicotine, and possibly smoking, may affect colitis by an action on mucosal eicosanoids and on adherent surface mucus secretion in the rectum and large bowel.

Low-dose aspirin inhibits platelet-induced contraction of the human isolated coronary artery. A role for additional 5-hydroxytryptamine receptor antagonism against coronary vasospasm?

BACKGROUND

The beneficial effect of low-dose aspirin in the prevention of coronary vasospasm is well documented. In this study, we investigated the contractile effect of human washed platelets on the human isolated coronary artery. We concentrated on the effect of low-dose aspirin (40 mg/d) taken by the platelet donor and on the efficacy of thromboxane A2 (TXA2) and 5-hydroxytryptamine (5-HT) receptor antagonists.

METHODS AND RESULTS

Human coronary artery segments were suspended in an organ bath set-up for isometric tension measurement. Platelets (10(9) to 3 x 10(10)/L) elicited concentration-dependent contractile responses of the coronary artery segments, reaching 28.4 +/- 7.1% of contractions induced by 100 mmol/L K+. The contractile response tended to be decreased in vessel segments with histological signs of early atherosclerosis. Contraction was significantly attenuated after pretreatment of the vessel segments with ketanserin (5-HT2 receptor antagonist, 1 mumol/L) or SQ30741 (TXA2 receptor antagonist, 0.01 mumol/L), reaching 8.8 +/- 2.3% and 3.2 +/- 2.2% of contraction to 100 mmol/L K+, respectively. Platelets obtained from the same platelet donors after they had taken aspirin (40 mg/d for 7 to 13 days) caused significantly lower contractile responses (7.6 +/- 2.7% of 100 mmol/L K+) associated with an almost selective inhibition of the synthesis of thromboxane measured in the organ bath solution (untreated platelets, 2.19 +/- 0.43 nmol/L; aspirin-treated platelets, 0.66 +/- 0.05 nmol/L). The amount of 5-HT secreted in the organ bath remained unaltered (65.17 +/- 9.94 and 64.03 +/- 8.98 nmol/L, respectively). This explains why ketanserin significantly attenuated the residual contractile responses caused by platelets obtained from aspirin-treated subjects, whereas SQ30741 caused minor, nonsignificant additional attenuation.

CONCLUSIONS

The results of the present study therefore suggest that additional antagonism of the contractile 5-HT receptors in the coronary artery may increase the efficacy of low-dose aspirin in vivo.

Increased platelet activating factor synthesis in experimental colitis after diclofenac and 5-amino-salicylic acid

We examined the role of platelet activating factor in dextran induced colitis in mice. The release of pro-inflammatory platelet activating factor by colonic mucosa after the application of prednisolone was markedly decreased, unaffected after treatment with the platelet activating factor receptor antagonist BN52021 and significantly increased after treatment with 5-amino-salicylic acid and diclofenac. This increase of platelet activating factor could be responsible for the harmful effects often seen after treatment with specific cyclooxygenase inhibitors during inflammation.

Nasal hyperreactivity and its effect on early and late sequelae of nasal challenge with house-dust mite extract

For a study on the relationship between nasal hyperreactivity to histamine and the nasal response to allergen, 14 rhinitis patients allergic to house-dust mites were challenged with histamine and 5 days later with a house-dust mite (HDM) extract. According to symptom scores, after allergen challenge two groups of patients were distinguished, i.e., isolated early and dual responders. The nasal response to histamine was significantly correlated with the amount of secretion (r = 0.71; p = 0.0039) and the number of sneezes (r = 0.78; p = 0.0016) induced by the HDM extract during the early reaction. The amount of allergen-induced secretion could be predicted from the response to histamine, skin reactivity to allergen, and blood eosinophils (multiple r = 0.90; p < 0.0001). Late-phase symptoms appearing between 3.5 and 9.5 hour after allergen challenge could be predicted from histamine responsiveness and skin reactivity (multiple r = 0.67; p = 0.004). Compared with early responders (LAR-) (n = 8), patients with early and late symptoms (LAR+) (n = 6) were characterized by a higher secretory responsiveness to histamine (p = 0.033), increased production of leukotrienes determined in nasal lavage fluid during the early response (p = 0.033), and elevated albumin levels occurring between 3.5 and 9.5 hours after challenge (p = 0.043). Late-phase symptoms were significantly correlated with albumin influx (r = 0.73; p = 0.001) and leukotrienes production (r = 0.60; p = 0.011) during the early reaction. In summary, nasal responsiveness to HDM extract was found to be closely associated with pre-existent nasal hyperreactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Eicosanoid production by the mucosa in inflammatory bowel disease after 5-ASA treatment

Eicosanoids were measured in biopsies of colonic mucosa from five patients with active ulcerative colitis before and after a four weeks of treatment with 5-amino-salicylic acid (5-ASA). Eicosanoid formation was determined after the addition of 14C-arachidonic acid and stimulation with calcium ionophore A23187. 5-ASA given intra-rectally caused a non-selective suppression of prostanoids, leukotrienes and hydroxy-eicosatetraenoic acids. Changes in arachidonic acid metabolism after 5-ASA treatment were not always reflected in changes in inflammation score.

Inflammatory mediators and activity of human peritoneal macrophages

Human peritoneal macrophages (hp-M phi) are a source of inflammatory mediators. After stimulation in vitro for 24 h with LPS there was a significant increase in cytokine production (IL-1, IL-6 and TNF alpha), but not in the production of eicosanoids from endogenous arachidonate. Leukotrienes are the predominant eicosanoids formed after stimulation with calcium ionophore for 15 min, while prostaglandin formation is insignificant. The fluorescence intensity of TPA-stimulated and DHR123 loaded hp-M phi (a measure of the respiratory burst) increases significantly in a short period of time. Hp-M phi will be useful as a model for testing the effects of anti-inflammatory drugs on eicosanoid and cytokine production and respiratory burst activity in vitro.

A comparison between two methods for measuring tumor necrosis factor in biological fluids

The current study was undertaken to compare two methods for the efficiency of measuring tumor necrosis factor (TNF-alpha) in biological fluids, which is species undependent, reliable, sensitive, simple and not expensive. We have compared the MTT tetrazolium cytotoxic assay [1,2] and the 3H-thymidine (3H-TdR) incorporation cytostatic assay for measuring the anti-tumor activity of human recombinant TNF-alpha, of human colonic tissue and of supernatants of in vitro stimulated human and rat peritoneal macrophages. Two target cell-lines, namely murine myelomonocytic leukaemia WEHI-164- and L-929-transformed murine fibroblast cell-lines, were used in the MTT assay. The L-929 line was also used in the 3H-TdR assay. WEHI-164 was more sensitive than the L-929 cell-line in the MTT cytotoxic assay. Furthermore, the MTT assay was more sensitive to TNF-alpha than the 3H-TdR assay. Both methods can be used for the detection of anti-tumor activity in biological fluids but the MTT cytotoxic method has the advantage of being more sensitive and more simple.

15-Hydroxy-eicosatetraenoic acid has minor anti-inflammatory properties in colitis

This study was performed to determine whether 15-HETE, which is the major metabolite of arachidonic acid (AA) in inflamed and normal human colonic tissue, has pro- or anti-inflammatory properties. To investigate these effects, 15-HETE (100 micrograms/kg/day) was administered rectally to mice with colitis induced by dextran sodium sulphate (DSS). Colons were removed and examined macroscopically and histologically and specimens were incubated with [14C]-AA and stimulated with A23187. Exogenous eicosanoids were separated by HPLC; the endogenously formed mediators were measured by radioimmunoassay. DSS produced a marked diffuse inflammatory response in the colon, associated with a raised inflammation score (mean 7.6 vs. < 0.5) and a significant increase in endogenously formed metabolites PGE2, LTB4 and 12-HETE. 15-HETE treatment resulted in a slight decrease in inflammation score (6.4 vs. 7.6) and a slight, but not significant, decrease in endogenous LTB4.

Protective effect of diclofenac sodium against endotoxic shock in anaesthetized pigs

The effect of diclofenac sodium was investigated on haemodynamics, haematologic and blood glucose values as well as the release of eicosanoids, tumor necrosis factor (TNF) and platelet activating factor (PAF) in anaesthetized pigs receiving 5 micrograms.kg-1 Escherichia coli lipopolysaccharide (LPS) over 60 min into the superior mesenteric artery. The animals were observed for an additional period of 2 h after the termination of LPS infusion. 15 of the 31 animals infused with LPS and not treated with diclofenac sodium died within 30 min after the commencement of LPS infusion (non-survivors), while the other 16 survived the experimental period of 3-h, though in a shock state (survivors). No alterations were observed in plasma concentrations of PAF or eicosanoids (TXB2, 6-keto PGF1 alpha and LTB4), but a marked increase was detected in TNF release in the non-survivors. A significant, though transient, increase in concentrations of PAF, TNF and eicosanoids studied characterized the survivors. Another group of 7 LPS-infused pigs was treated with diclofenac sodium (2 mg, kg-1, i.v. bolus 60 min before the start of LPS infusion, followed by a continuous infusion of 1 mg kg-1 h-1) 1 mg/kg-1/h-1. This treatment prevented death and shock despite the high concentrations of TNF and PAF. Concentrations of both cyclooxygenase and 5-lipoxygenase enzymes products were reduced. These data indicated that the beneficial effect of diclofenac sodium in LPS induced shock may be related to the reduced production of eicosanoids.

Effects of long-acting somatostatin analog (SMS 201-995) on eicosanoid synthesis and survival in rats with acute necrotizing pancreatitis

The effects of a long-acting somatostatin analog (SMS 201-995) were studied in an established model of acute necrotizing pancreatitis in rats. SMS 201-995, when given prior to induction of pancreatitis, decreased the mortality rate from 100% to 40% (P = 0.0001). When treatment was given after induction of pancreatitis, the mortality rate was 75% (P = 0.2). Administration of SMS 201-995 did not influence the serum concentrations of amylase markedly, but the lipase levels were significantly lowered (P less than 0.05). The low levels of serum insulin and the glucose level in whole blood were not influenced. The volume of ascitic fluid was reduced (P less than 0.01). Moreover, less peritoneal fat necrosis was seen, suggesting a reduction in toxic factors in the ascitic fluid. Treatment with SMS 201-995 prior to induction of pancreatitis caused a significant increase in the levels of circulating 6-keto-PGF1 alpha, the stable metabolite of prostaglandin I2 (P less than 0.01). The levels of thromboxane B2 and prostaglandin E2 did not change significantly. The present data support the hypothesis that SMS 201-995 is an activator of prostaglandin I2, thereby modifying the course of the disease.