1
|
Kerttula T, Kaukinen S, Seppälä E, Riutta A, Mucha I, Ylitalo P, Alanko J. Theophylline infusion modulates prostaglandin and leukotriene production in man. Prostaglandins Leukot Essent Fatty Acids 1997; 57:555-60. [PMID: 9431822 DOI: 10.1016/s0952-3278(97)90560-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Although theophylline has been used in the treatment of asthma for decades, it is not a first line choice any more. It is a well-known bronchodilator, but was recently discovered also to be an anti-inflammatory, immunomodulatory and bronchoprotective agent. Therefore we wanted to establish the role of theophylline on prostaglandin and leukotriene production, which plays a part in the pathogenesis of asthma. Theophylline was infused (bolus 5 mg/kg in 15 min and infusion 0.4 mg/kg/h for 1 h 45 min) into healthy volunteers. Thromboxane B2, prostaglandin E2 and leukotriene E4 were measured from the A23187-stimulated whole blood samples and stable metabolites of thromboxane A2; prostacyclin and leukotriene E4 were measured from urine. Theophylline increased prostaglandin E2 production and decreased leukotriene E4 production ex vivo in whole blood, thus increasing the prostanoid/leukotriene ratio. It did not change thromboxane B2 production stimulated by either spontaneous clotting or A23187 in the whole blood. Theophylline had hardly any effect on in vivo thromboxane, prostacyclin and leukotriene E4 production measured as urinary metabolites, 11-dehydro-thromboxane B2, 2,3-dinor-6-keto-prostaglandin F1alpha and leukotriene E4, respectively. Serum theophylline concentrations were at the lower level of normal therapeutic range during the infusion. The increase in PGE2 and the decrease in LTE4 synthesis ex vivo may offer a new explanation for the mode of antiasthmatic action of theophylline. It is notable that this phenomenon occurs at low serum theophylline concentrations. These results confirm the idea that theophylline has an anti-inflammatory and bronchoprotective action and support the use of theophylline as a therapeutic agent in asthmatic patients.
Collapse
Affiliation(s)
- T Kerttula
- Department of Clinical Chemistry, Tampere University Hospital, Finland
| | | | | | | | | | | | | |
Collapse
|
2
|
Plaza V, Prat J, Rosellò J, Ballester E, Ramis I, Mullol J, Gelpí E, Vives-Corrons JL, Picado C. In vitro release of arachidonic acid metabolites, glutathione peroxidase, and oxygen-free radicals from platelets of asthmatic patients with and without aspirin intolerance. Thorax 1995; 50:490-6. [PMID: 7597660 PMCID: PMC1021217 DOI: 10.1136/thx.50.5.490] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND An abnormal platelet release of oxygen-free radicals has been described in acetylsalicylic acid (aspirin)-induced asthma, a finding which might suggest the existence of an intrinsic, specific platelet abnormality of arachidonic acid metabolism in these patients. The objective of this study was to evaluate platelet arachidonic acid metabolism in asthmatic patients with or without intolerance to aspirin. METHODS Thirty subjects distributed into three groups were studied: group 1, 10 healthy subjects; group 2, 10 asthmatic patients with aspirin tolerance; and group 3, 10 aspirin-intolerant asthmatics. Platelets were isolated from blood, preincubated with 3H-arachidonic acid for 30 minutes and then incubated for 10 minutes with platelet activating factor (PAF) and aspirin. Cyclo-oxygenase (thromboxane, PGE2, PGF2 alpha, and HHT) and lipoxygenase (12-HETE) arachidonic acid metabolites were measured by high pressure liquid chromatography. Release of oxygen free radicals after incubation with PAF and aspirin was measured by chemiluminescence. Platelet levels of glutathione peroxidase (GSH-Px) were also measured using spectrophotometry. RESULTS Platelets from aspirin-intolerant asthmatic patients produced higher quantities of arachidonic acid metabolites than the control group at baseline conditions. This increase was significant only for lipoxygenase products. No differences were found amongst the three groups in the response of arachidonic acid metabolism to PAF and aspirin. Incubation with aspirin but not with PAF caused an increase in oxygen-free radical production in aspirin-intolerant patients whereas in aspirin-tolerant patients PAF, rather than aspirin, was the more potent stimulus for oxygen-free radical production. No differences in GSH-Px levels were found amongst the three groups. CONCLUSIONS These results suggest that the platelet lipoxygenase pathway is activated in aspirin-intolerant patients and that the production of oxygen-free radicals may differentiate aspirin-tolerant from aspirin-intolerant asthmatic subjects. Our study, however, does not support the hypothesis that an increase in lipoxygenase products may be responsible for oxygen-free radical production. Moreover, a lowered platelet GSH-Px activity does not seem to be involved in this phenomenon.
Collapse
Affiliation(s)
- V Plaza
- Servei de Pneumologia, Hospital Clinic, Departament de Medicina, Facultat de Medicina, Barcelona, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
3
|
Kocan GP, Partis RA, Mueller RA, Smith WG, Nakao A. Contrasting effects of two arachidonate 5-lipoxygenase inhibitors on formyl-methionyl-leucyl-phenylalanine (fMLP) and complement fragment 5a induced human neutrophil superoxide generation. Biochem Pharmacol 1994; 47:1029-37. [PMID: 8147901 DOI: 10.1016/0006-2952(94)90414-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
SC-45662 and SC-41661A, selective arachidonate 5-lipoxygenase (5-LO) inhibitors, had markedly different effects on formyl-methionyl-leucyl-phenylalanine (fMLP) and complement fragment 5a (C5a) induced superoxide release from human neutrophils (PMNs). SC-45662 inhibited superoxide generation induced by fMLP and C5a with IC50 values of 12 and 5 microM, respectively. Furthermore, SC-45662 was capable of inhibiting fMLP and C5a induced superoxide release in PMNs primed with bacterial lipopolysaccharide, tumor necrosis factor-alpha and other priming agents. SC-41661A, a compound from the same chemical series as SC-45662, did not inhibit or induce superoxide generation, but instead primed PMNs for fMLP and C5a induced superoxide generation. The induced superoxide release was concentration dependently enhanced 2 to 4-fold at 5-50 microM. Superoxide release induced by phorbol myristate acetate or serum-activated zymosan was unaffected by either SC-45662 or SC-41661A. The regulation of superoxide generation by these compounds, both of which have the identical oxidation-reduction pharmacophore, was clearly independent of their effects on 5-LO activity. Furthermore, the mechanism by which SC-45662 and SC-41661A alter superoxide generation did not appear to depend on inhibition of xanthine oxidase, catalase or superoxide dismutase. These new compounds provide effective tools for further investigation of the relationship of these two biochemical oxidative systems.
Collapse
Affiliation(s)
- G P Kocan
- Infectious Diseases Research Department, Searle Research and Development, Skokie, IL 60077
| | | | | | | | | |
Collapse
|
4
|
Alanko J, Riutta A, Vapaatalo H. Effects of catecholamines on eicosanoid synthesis with special reference to prostanoid/leukotriene ratio. Free Radic Biol Med 1992; 13:677-88. [PMID: 1459485 DOI: 10.1016/0891-5849(92)90041-e] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Catecholamines (adrenaline, dopamine, and noradrenaline) stimulate prostanoid synthesis by acting as "cosubstrates." On the other hand, many inhibitors of leukotriene synthesis, such as nordihydroguaiaretic acid and caffeic acid, have a catecholic structure. Catecholamines have opposite effects on prostanoid and leukotriene synthesis in human polymorphonuclear leukocytes and whole blood. Basic phenols (catechol, hydroquinone, and phenol) also increase the prostanoid/leukotriene ratio in polymorphonuclear leukocytes. These actions correlate to their antioxidant capacities and oxidation potentials, and they are not mediated via adrenergic receptors. There is only limited knowledge about the effects of natural catecholamines on the prostanoid/leukotriene ratio in vitro and in vivo. Indirect data suggest that catecholamines could increase prostanoid production in physiological or pathological situations, such as heavy physical exercise, myocardial infarction, and surgical stress. This interaction may also be of clinical importance in asthma, gastric ulcer, and psoriasis, where decreased prostanoid/leukotriene ratios have been reported.
Collapse
Affiliation(s)
- J Alanko
- Department of Biomedical Sciences, University of Tampere, Finland
| | | | | |
Collapse
|
5
|
Rio P, Tunon de Lara JM, Marthan R, Taytard A. IgE binding inhibits arachidonic acid-induced chemiluminescence of human platelets. Clin Exp Allergy 1992; 22:91-7. [PMID: 1532337 DOI: 10.1111/j.1365-2222.1992.tb00119.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Arachidonic acid (AA)-induced chemiluminescence (CHL) was studied in vitro by means of a luminometer in platelets from nine healthy volunteers and six allergic patients. The amplitude of the CHL signal increased with AA concentration from 250 microM to 7 mM. At a low AA concentration (250 microM), the CHL signal consisted of two peaks. The first one occurred at 6 +/- 3 sec and the second one at 90 +/- 15 sec (n = 9). The mean amplitude of these peaks was 1.95 +/- 0.61 mV/sec and 0.82 +/- 0.22 mV/sec for normal subjects, and 2.35 +/- 0.62 mV/sec and 0.78 +/- 0.26 mV/sec for allergic patients, respectively. Aspirin (a cyclooxygenase inhibitor) and baicalein (a lipoxygenase inhibitor) reduced in a concentration-dependent manner, the first and second peak, respectively. The binding of immunoglobulin E (IgE) alone to platelets from both normal and allergic subjects inhibited both the first and second peak of AA-induced CHL. This inhibitory effect was specifically due to the action of IgE as it was (i) concentration-dependent and (ii) not observed when immunoglobulin G (IgG) was substituted for IgE. It is concluded that in normal subjects, as well as in allergic patients, the binding of IgE alone to its specific receptor on human platelets could alter arachidonate metabolism that probably involves cyclooxygenase and lipoxygenase pathways.
Collapse
Affiliation(s)
- P Rio
- Service des Maladies Respiratoires, Hôpital du Haut Lévêque, CHR de Bordeaux, Pessac, France
| | | | | | | |
Collapse
|
6
|
Hosni R, Chabannes B, Pacheco Y, Moliere P, Grosclaude M, Perrin Fayolle M, Lagarde M. Leukotriene B4 levels from stimulated neutrophils from healthy and allergic subjects: effect of platelets and exogenous arachidonic acid. Eur J Clin Invest 1991; 21:631-7. [PMID: 1663869 DOI: 10.1111/j.1365-2362.1991.tb01420.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Leukotriene B4 (LTB4) levels were measured in peripheral blood neutrophils from allergic and healthy donors after stimulation by calcium ionophore A 23187. This level was higher in neutrophils from allergic subjects than in neutrophils from healthy subjects in the presence as well as in the absence of exogenous arachidonic acid. Platelets from allergics increased LTB4 levels from neutrophils from allergics but not levels in those from healthy donors. Moreover, platelets from healthy subjects reduced LTB4 in neutrophils from both groups. These results suggest that biochemical differences exist in neutrophils and platelets from allergics which contribute to changes in arachidonic acid metabolism via the 5-lipoxygenase pathway. In addition, they support the concept that platelets may play an important role in the regulation of neutrophil LTB4 levels, possibly by affecting the 5-lipoxygenase activity during the course of allergic inflammatory reactions.
Collapse
Affiliation(s)
- R Hosni
- Hôpital Sainte-Eugénie, Saint Genis Laval, France
| | | | | | | | | | | | | |
Collapse
|
7
|
|
8
|
Affiliation(s)
- C P Page
- Department of Pharmacology, King's College London, University of London, England
| |
Collapse
|
9
|
Hasselmark L, Malmgren R, Unge G, Zetterström O. Lowered platelet glutathione peroxidase activity in patients with intrinsic asthma. Allergy 1990; 45:523-7. [PMID: 2252163 DOI: 10.1111/j.1398-9995.1990.tb00528.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Platelet glutathione peroxidase (GSH-Px) activity and serum selenium (Se) levels were determined in 20 patients with intrinsic asthma. Nine of the patients had NSAID-intolerance. The mean value of GSH-Px activity in the patients was 47.0 +/- 7.1 U/10(11) platelets, which is significantly lower than that of 56.4 +/- 12 U/10(11) platelets in the controls (P less than 0.01). There was also a tendency towards lowered Se levels in the patients compared with controls. The results are discussed in view of the protective role of GSH-Px against oxidative stress and the tentative regulatory function of GSH-Px in arachidonic acid metabolism.
Collapse
Affiliation(s)
- L Hasselmark
- Dept. of Experimental Surgery, Karolinska Hospital, Stockholm, Sweden
| | | | | | | |
Collapse
|
10
|
Parantainen J, Alanko J, Moilanen E, Metsä-Ketelä T, Asmawi MZ, Vapaatalo H. Catecholamines inhibit leukotriene formation and decrease leukotriene/prostaglandin ratio. Biochem Pharmacol 1990; 40:961-6. [PMID: 2117928 DOI: 10.1016/0006-2952(90)90480-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Adrenaline, noradrenaline, isoprenaline, and to a lesser extent dopamine inhibit the release of leukotriene (LT) B2 from calcium ionophore-stimulated human polymorphonuclear leukocytes, while the release of prostaglandin (PG) E2 is proportionally elevated. The inactivity of salbutamol, a noncatechol adrenergic beta 2-receptor agonist, and the inability of propranolol to antagonize the effects of adrenaline, suggest the mediation through beta-receptor independent mechanisms. Neither are alpha-1-receptors involved, as prazosin, a specific antagonist, fails to inhibit the reaction. As the principles for biochemical regulation of LT- and PG-production are met by catecholamines in several tissues, the mechanism is considered to be of general physiological importance. Catecholamines may function as coenzymes/antioxidants which, by altering the redox state of the enzyme iron or heme, decrease the LT/PG ratio thus protecting the organism against tissue anaphylaxis and other LT-related pathophysiology.
Collapse
|
11
|
Cortijo J, Ortiz JL, Sanz C, Sarría B, Pascual R, Perpiñá M, Esplugues J, Morcillo EJ. Modification by indomethacin of airway contractile responses in normal and sensitized guinea-pigs. Eur J Pharmacol 1989; 162:467-73. [PMID: 2744080 DOI: 10.1016/0014-2999(89)90337-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Active sensitization of guinea-pigs resulted in an increase in responsiveness and sensitivity of tracheal and lung parenchymal strips to CaCl2 (in K+-depolarised tissue), KCl, acetylcholine and histamine. Indomethacin (5 microM) preferentially enhanced the response of tracheal strips from normal animals to histamine and to a lesser extent acetylcholine but not to CaCl2 or KCl. A similar trend was observed in sensitized tissues. Indomethacin pretreatment did not cause changes in responsiveness or sensitivity of lung parenchymal strips from normal or sensitized guinea-pigs to the agonists tested. It is concluded that immunological sensitization produced a non-specific hyperresponsiveness in trachea and lung parenchymal strips. Conversely, cyclooxygenase inhibition by indomethacin elicited a selective increase in the responsiveness to certain agonists in central but not in the peripheral airways.
Collapse
Affiliation(s)
- J Cortijo
- Departamento de Farmacologia y Farmacotecnia, Universitat de València, Madrid, Spain
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Doerr IL, Kaufman J, Brooks RR. Effects of orpanoxin on arachidonic acid metabolism of human polymorphonuclear leucocytes and platelets in vitro. Clin Exp Pharmacol Physiol 1988; 15:539-49. [PMID: 3152163 DOI: 10.1111/j.1440-1681.1988.tb01112.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
1. The effect of orpanoxin, a nonsteroidal anti-inflammatory drug, on cyclo-oxygenase and lipoxygenase activity in human polymorphonuclear leucocytes (PMNL) and platelets was studied ex vivo to see if lipoxygenase inhibition contributed to orpanoxin's mechanism of action. 2. In PMNL, orpanoxin (50, 100, and 200 mumols/l), like indomethacin (100 mumols/l), had little effect on synthesis of leukotriene B4 or 5S-hydroxy-6-trans,8,11,14-cis-eicosatetraenoic acid. BW755c at 100 mumols/l inhibited synthesis of both. 3. In PLT, orpanoxin (100 mumols/l) inhibited formation of cyclo-oxygenase products (thromboxanes, prostaglandins, and 12-L-hydroxy-5,8,10-heptadecatrienoic acid) and increased synthesis of the lipoxygenase product, 12S-hydroxy-5,8-cis,10-trans,14-cis-eicosatetraenoic acid. Effects of indomethacin (100 mumols/l) and benoxaprofen (100 mumols/l) in platelets were qualitatively similar to those of orpanoxin. 4. These results indicate that the discrepancy between the low potency of orpanoxin in inhibiting bovine seminal vesicle cyclo-oxygenase in vitro and its high potency as an anti-inflammatory agent in vivo is not explained by its having an additional lipoxygenase inhibitory mechanism.
Collapse
Affiliation(s)
- I L Doerr
- Department of Medicine, State University of New York, Stony Brook
| | | | | |
Collapse
|
13
|
Audera C, Rocklin R, Vaillancourt R, Jakubowski JA, Deykin D. Altered arachidonic acid metabolism and platelet size in atopic subjects. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1988; 46:352-9. [PMID: 3123110 DOI: 10.1016/0090-1229(88)90054-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The release and metabolism of endogenous arachidonic acid (AA) in physiologically activated platelets obtained from 11 atopic patients with allergic rhinitis and/or asthma was compared to that of sex- and age-matched nonatopic controls. Prelabeled [3H]AA platelets were stimulated with thrombin or collagen and the amount of free [3H]AA and radiolabeled metabolites released were measured by high-performance liquid chromatography. The results obtained indicate that although the incorporation of [3H]AA into platelet phospholipids and total release of 3H-radioactivity upon stimulation were comparable in the two groups, the percentage of 3H-radioactivity released from platelets as free AA was significantly lower (P less than 0.01) in the atopic group. The reduction in free [3H]AA was accompanied by an increase (P less than 0.01) in the percentage of 3H-radioactivity released as cyclooxygenase products in atopic platelets (compared to nonatopic cells) after stimulation with 10 and 25 micrograms/ml collagen. The amount of platelet lipoxygenase product released was comparable between the two groups. Although the blood platelet counts were similar, the mean platelet volume was statistically higher (P less than 0.01) in the atopic group. These results indicate that arachidonic acid metabolism in atopic platelets is altered, the pathophysiological significance of which remains to be clarified.
Collapse
Affiliation(s)
- C Audera
- Department of Medicine, New England Medical Center, Boston, Massachusetts
| | | | | | | | | |
Collapse
|
14
|
|
15
|
Housholder GT. Intolerance to aspirin and the nonsteroidal anti-inflammatory drugs. J Oral Maxillofac Surg 1985; 43:333-7. [PMID: 2985772 DOI: 10.1016/0278-2391(85)90252-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A constant enigma has been the ability of aspirin and other structurally unrelated nonsteroidal anti-inflammatory drugs to induce non-IgE mediated allergic reactions. These reactions range from mild hypersensitivity to fatal anaphylaxis. Recent biochemical and pharmacologic studies involving the oxidative metabolism of arachidonic acid in different cells and tissues have provided insights into how this could conceivably occur. The products of cyclo-oxygenase and lipoxygenase pathways of arachidonic acid metabolism and their interactions may provide an approach, if not the solution, to the problem of aspirin intolerance.
Collapse
|
16
|
|
17
|
Mayer B, Rauter L, Zenzmaier E, Gleispach H, Esterbauer H. Characterization of lipoxygenase metabolites of arachidonic acid in cultured human skin fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA 1984; 795:151-61. [PMID: 6432053 DOI: 10.1016/0005-2760(84)90116-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cultured human skin fibroblasts were incubated in the presence of [14C]arachidonic acid (50 microM; 1 m Ci/mmol) and the divalent cation ionophore A23187 at 37 degrees C for 60 min. The metabolites formed were extracted from the cell-free medium in diethyl ether, separated by thin layer chromatography and identified unequivocally by GC-MS. The distribution of the arachidonic acid metabolites as estimated from the recovered radioactivity showed as major product prostaglandin E2 (26%). Minor amounts of other prostaglandins, i.e., 6-oxo-prostaglandin F1 alpha (1%), prostaglandin F2 alpha (1%), prostaglandin D2 (0.5%) and prostaglandin A2 (1%) were also present. In addition to the prostaglandins, monohydroxy fatty acids (4.5%) were also detected. This fraction contained 33% 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT), 22% 11-hydroxy-5,8,11,14-eicosatetraenoic acid (11-HETE) and 31% 15-hydroxy-5,8,11,13-eicosatetraenoic acid (15-HETE). Lipid extracts of the cells did not show any detectable amount of the monohydroxy fatty acids, indicating that they are not incorporated metabolically in the cellular lipids. The monohydroxy fatty acids originate mainly from the exogenously added arachidonic acid as evidenced by the 2H/H ratio (30:1) from experiments with octadeuterated arachidonic acid [( 2H8]arachidonic acid). Indomethacin inhibited the formation of all prostaglandins, HHT and 11-HETE; moreover, eicosatetraynoic acid (also blocked the formation of 15-HETE. From these results, it can be concluded that in human skin fibroblasts prostaglandin E2 is the major product of the cycloxygenase pathway, while 15-HETE is the main lipoxygenase product.
Collapse
|
18
|
Chang J, Skowronek MD, Cherney ML, Lewis AJ. Differential effects of putative lipoxygenase inhibitors on arachidonic acid metabolism in cell-free and intact cell preparations. Inflammation 1984; 8:143-55. [PMID: 6430801 DOI: 10.1007/bf00916090] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The effects of nordihydroguairetic acid (NDGA), 3-amino-1-trifluoromethyl-)-phenyl-2-pyrazoline (BW755c), eicostatetraynoic acid (ETYA), phenidone, quercetin, and indomethacin (INDO) on the synthesis of 15-hydroxyeicosatatetraenoic acid (15-HETE) from soybean 15-lipoxygenase, leukotriene B4 (LTB4) from 5-lipoxygenase, and prostaglandin E2 (PGE2) from cyclooxygenase enzymes of rat neutrophils and mouse peritoneal macrophages were investigated. All of the drugs caused a dose-related inhibition of increased oxygen consumption by soybean 15-lipoxygenase in the presence of arachidonic acid and the rank order of potency was phenidone greater than or equal to BW755c greater than ETYA greater than quercetin greater than NDGA greater than indomethacin. The reduction in oxygen consumption correlated with a reduction of 15-HETE formation as identified by high-performance liquid chromatography. Apart from indomethacin, these drugs were also effective against the rat neutrophil 5-lipoxygenase, although the rank order of potency did not correlate with that obtained with soybean 15-lipoxygenase. Furthermore, in both A23187-activated rat neutrophils and zymosan-activated mouse peritoneal macrophages the synthesis of prostaglandins was inhibited by all of these drugs. In the neutrophils, the rank order of potency was INDO greater than ETYA greater than BW755c greater than quercetin greater than NDGA greater than phenidone, whereas in mouse peritoneal macrophages, the order was INDO greater than ETYA greater than BW755c greater than NDGA greater than quercetin greater than phenidone. These results suggest that putative lipoxygenase inhibitors exhibit both qualitative and quantitative differences in their effects on both lipoxygenases and cyclooxygenases.
Collapse
|
19
|
Abstract
The leukotrienes, prominent mediators of immediate hypersensitivity and inflammation, are derived from the major product of leukocyte lipoxygenase activity, 5-HPETE. An alternative pathway for 5-HPETE metabolism is reduction to 5-HETE. I hypothesize that, in analogy to its established role in platelet lipoxygenase metabolism, the selenium-dependent glutathione peroxidase mediates this reduction. If so, supplementary selenium may decrease leukotriene production, and thus have value as a nutritional adjuvant in the management of asthma and various other inflammatory disorders.
Collapse
|
20
|
|
21
|
Abstract
Aspirin inhibits cyclo-oxygenase by an irreversible time-dependent process of inactivation; this mechanism appears to be responsible for precipitation of asthmatic attacks in about 5%-10% of adult asthmatic patients. Besides aspirin, all other cyclo-oxygenase inhibitors induce bronchoconstriction in sensitive patients, while nonsteroidal anti-inflammatory drugs without anti-cyclo-oxygenase activity can be taken by the same patients with impunity. While aspirin-sensitive patients should avoid the potential for adverse reactions, there are rare reports of bronchodilation following ingestion of aspirin and aspirinlike drugs.
Collapse
|
22
|
Abstract
The Ca2+ requirements for excitation-contraction coupling in smooth muscle may be satisfied from both intracellular and extracellular sources, the relative extent of use of which is both tissue- and stimulant-dependent. Extracellular Ca2+ is apparently mobilized through two separate pathways, receptor operated (ROC) and potential dependent (PDC) Ca2+ channels. The latter process is sensitive to the Ca2+-channel antagonists, a heterogeneous group of compounds including verapamil, nifedipine and diltiazem. Ca2+ mobilization in respiratory smooth muscle is reviewed. The available evidence for this multiple stimulant-sensitive system indicates that both intra- and extracellular sources of Ca2+ are used. Data from bovine, canine and guinea pig tracheal muscle indicate, from studies of Ca2+-dependence of response and Ca2+ channel antagonist sensitivity, that the extent of use of extracellular Ca2+ lies in the order K+ greater than histamine greater than or equal to 5-hydroxytryptamine greater than acetylcholine. The bronchodilator activity of the Ca2+ channel antagonists is noted. Bronchial hyperreactivity is characterized by an increased sensitivity to a variety of stimulants including cold air, exercise, histamine and acetylcholine. The possible origins of this defect are noted. It is suggested that a defect in Ca2+ mobilization or in the receptor - Ca2+ mobilization coupling process at the level of the smooth muscle may constitute an important underlying cause of bronchial hyperreactivity. Potential analogies to reactivity changes seen in hypertensive vascular smooth muscle are noted.
Collapse
|
23
|
Nijkamp FP, Sitsen JM. Leukotrienes, allergy and inflammation. PHARMACEUTISCH WEEKBLAD. SCIENTIFIC EDITION 1982; 4:165-71. [PMID: 6296757 DOI: 10.1007/bf01959134] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Immunological and non-immunological injury induce as a result of the action of the enzyme lipoxygenase the release of a series of arachidonic acid metabolites known as leukotrienes. The leukotrienes play an important role in allergic and inflammatory disease. Leukotrienes C4, D4 and E4 which recently have been recognized as constituents of the allergic mediator slow reacting substance of anaphylaxis (SRS-A) induce powerful bronchoconstriction, plasma exudation and weal and flare responses. Leukotriene B4 is involved in the regulation of chemotaxis, chemokinesis and other aspects of both cellular and vascular inflammation. The development of specific lipoxygenase inhibitors may lead to a new class of drugs for the treatment of bronchial asthma and chronic inflammatory diseases.
Collapse
|