Urinary leukotriene E4 excretion: a biomarker of inflammatory bowel disease activity.

BACKGROUND: Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory disorders collectively referred to as inflammatory bowel diseases (IBD). Cysteinyl leukotrienes are proinflammatory 5-lipoxygenase-derived products that play a major role in the immune and inflammatory response. Consequently, they may be involved in the pathogenesis of IBD. The aim of this study was therefore to evaluate 1) the urinary excretion of leukotriene E(4) (LTE(4)) in IBD patients and healthy volunteers, and 2) the association between LTE(4) production and the activity (relapse/remission) of the disease. METHODS: IBD patients and healthy volunteers were prospectively recruited. CD and UC activity was determined on inclusion with the Crohn's Disease Activity Index and Clinical Activity Index, respectively. Urine was collected and the urinary excretion of LTE(4) was measured by liquid chromatography tandem mass spectrometry. RESULTS: 32 CD patients, 28 UC patients, and 30 controls were enrolled in the study. LTE(4) urinary excretion was significantly increased (P < 0.01) in CD [52.0 pg/mg creatinine (10th-90th percentiles: 26.2-148.0)] and UC [64.1 pg/mg creatinine (10th-90th percentiles: 26.7-178.0)] patients compared to controls [32.3 pg/mg creatinine (10th-90th percentiles: 21.8-58.8)]. LTE(4) levels were higher (P < 0.001) in patients with active disease than in patients in remission, for whom the levels of LTE(4) were similar to the levels of controls. CONCLUSIONS: Cysteinyl leukotriene pathway activation could contribute to the inflammation associated with IBD. The quantification of urinary LTE(4) could be an interesting noninvasive biomarker for the assessment of IBD activity.

[Immunosuppressive drugs and highly active antiretroviral therapy: pharmacokinetic interactions]. / Médicaments immunosuppresseurs et antirétroviraux: une association riche en interactions.

The development of highly active antiretroviral therapy has greatly improved HIV-infected patient survival. However, the increased life expectancy associated with the management of opportunistic infections might favour the onset of severe organic failure that could require organ transplantation. The use of immunosuppressive drugs in association with antiretroviral therapy will generate pharmacodynamic and pharmacokinetic interactions. In this context, therapeutic drug monitoring is of great importance to improve therapeutic management of patients.

Functional assessment of vascular reactivity after chronic intermittent hypoxia in the rat.

We recently developed a model of chronic intermittent hypoxia (CIH) (FiO2 5%, 8 h/day, 35 days) in the rat that was associated with an increased infarction in isolated heart. The aim of the present study was to characterize its functional consequences on vasoreactivity. Aorta and carotid artery were studied using organ bath technique while mesenteric vascular bed was perfused. In the three vascular beds, relaxation to acetylcholine was similar in CIH and control normoxic (NX) rats. Contractions to noradrenaline and angiotensin II were similar between CIH and NX rats. In contrast, contraction to endothelin-1 was increased by 17% (P < 0.05) in carotid artery from CIH rats. Indomethacin pre-treatment reduced by 24% (P < 0.001) contraction to endothelin-1 in carotid artery from CIH rats only. These data suggested that 35-day CIH-exposure induced no change in endothelial function of aorta, carotid artery and mesenteric bed. In contrast, CIH-exposure induced an increased contractile response to endothelin-1 in carotid artery, presumably owing to the release of constrictor cyclooxygenase-derived products.

Effect of 5-lipoxygenase blockade on blood pressure and acetylcholine-evoked endothelium-dependent contraction in aorta from spontaneously hypertensive rats.

OBJECTIVE: Cysteinyl leukotrienes (cysLT) are pro-inflammatory and vasoactive products suspected to be involved in the regulation of vascular tone and blood pressure in hypertension. DESIGN: We investigated, in spontaneously hypertensive rats (SHR), the involvement of cysLT in the in-vivo regulation of blood pressure and the in-vitro endothelium-dependent contraction to acetylcholine in isolated aorta. METHODS: SHR and Wistar-Kyoto rats (WKY) were orally treated for 3 weeks with either the cysLT biosynthesis inhibitor MK-886 (0.1 mg/ml) or vehicle. After mean arterial blood pressure (MABP) measurement, aortic ring preparations were removed from all groups of animals, and contractions and relaxations were monitored subsequent to stimulation with acetylcholine. RESULTS: MABP was higher in SHR. Chronic treatment with MK-886 did not alter MABP in either SHR or WKY. In the presence of the N-nitro-L-arginine (L-NA, 100 micromol/l), and on prostaglandin F2alpha (PGF2alpha)-induced tone, acetylcholine evoked concentration-dependent contractions in intact aortic rings from SHR only. Pretreatment with either MK-886 (10 micromol/l), the 5-lipoxygenase (5-LO) inhibitor AA861 (10 micromol/l), or the cysLT1 receptor antagonist MK571 (1 micromol/l) reduced (P < 0.05) acetylcholine-induced contractions in intact aortic rings from SHR only. Acetylcholine-induced contractions were weaker (P < 0.01) in SHR chronically treated with MK-886 than in SHR. In the presence of L-NA, leukotriene (LT) D4 induced greater (P < 0.05) concentration-dependent contractions in aortic rings from SHR than from WKY. MK571 abolished LTD4-evoked contractions. CONCLUSION: These data suggested that 5-LO-derived products, through the activation of cysLT1 receptors, could be involved in the endothelium-dependent contraction to acetylcholine in aorta from SHR but not in the regulation of MABP in SHR.

Urinary leukotriene E4 excretion is increased in type 1 diabetic patients: a quantification by liquid chromatography-tandem mass spectrometry.

OBJECTIVE: Diabetes mellitus is associated with inflammatory state and increased cardiovascular mortality. Leukotrienes are arachidonic acid metabolites derived from the 5-lipoxygenase pathway that possess vasoactive, chemotactic and proinflammatory properties. The aim of this study was to evaluate (1) the urinary excretion of leukotriene E4 (LTE4) in type 1 diabetic subjects and healthy volunteers and (2) the influence of glycemic control attested by HbA(1C) on LTE4 excretion. METHODS AND RESULTS: Urinary excretion of LTE(4), measured by liquid chromatography-tandem mass spectrometry, was significantly (P=0.033) increased in diabetic patients (median [10th-90th percentiles]: 42.1 pg/mg creatinine [16.7-71.4], n=34), compared to healthy subjects (25.5 pg/mg creatinine [13.9-54.1], n=28). Subgroup analysis indicated a trend towards increased LTE4 excretion in patients with poor glycemic control [(HbA(1C)> or =9% or plasma glucose >18 mmol/L): 43.3 pg/mg creatinine [21.6-70.5], n=14], whereas no difference was observed between patients with good metabolic control [(HbA(1C)< or =7.5%): 36.4 pg/mg creatinine [15.8-83.4], n=20] and healthy subjects. CONCLUSIONS: This study suggested that increased LTE4 excretion in type 1 diabetic state might reflect systemic activation of the 5-lipoxygenase pathway. It could be a determinant of underlying inflammatory state and vascular disease.

Vascular effects of 15-F2t-isoprostane in spontaneously hypertensive rats.

F2-isoprostanes are a family of compounds derived from arachidonic acid by free radical-catalyzed peroxidation. Among F2-isoprostanes, 15-F2t-IsoP is a vasoconstrictor in animal and human vascular beds. Several recent studies found increased 15-F2t-IsoP levels in animal models of hypertension. However, no data is available on the vascular effect of 15-F2t-IsoP in such models. The contractile responses of 15-F2t-IsoP (10(-9) to 3 x 10(-5) mol/L) were tested on rat thoracic aortic rings in spontaneously hypertensive rats (SHR) compared with Wistar-Kyoto (WKY) rats. The contraction induced by 15-F2t-IsoP was not significantly different in aortic rings from WKY rats and SHR (Emax 139% +/- 5% vs. 134% +/- 6%, respectively) and was mediated through thromboxane A2-prostaglandin H2 receptor activation as shown by the rightward shift of the concentration-contraction curves in presence of GR 32191, a specific thromboxane A2-prostaglandin H2 receptor antagonist. Endothelial denudation increased the maximal contraction compared to intact rings induced by 15-F2t-IsoP in both WKY rats (170% +/- 20% vs. 139% +/- 5%, p < 0.05) and SHR (194% +/- 11% vs. 134% +/- 6%, p < 0.01), whereas pretreatment with Nomega-nitro-L-arginine (10(-4) mol/L) or with indomethacin (10(-5) mol/L) increased the maximal contraction to 15-F2t-IsoP in WKY rats but not in SHR. SHRs treated with an angiotensin-converting enzyme inhibitor, enalapril, for four weeks showed decreased maximal contraction to 15-F2t-IsoP in vessels with and without endothelium compared with untreated SHR. In conclusion, 15-F2t-IsoP-induced vasoconstriction is similar in SHR compared with WKY rats. Endothelium modulates 15-F2t-IsoP contraction in both strains. However, whereas this effect is mediated through nitric oxide- and cyclooxygenase-dependent pathways in WKY rats, other mediators are implicated in SHR.

15-F-isoprostane and 5-F-isoprostane are not triggers of myocardial preconditioning.

1. Myocardial ischaemia-reperfusion in humans is associated with increased formation of 15-F(2t)-isoprostane and 5-F(2t)-isoprostane (15-F(2t)-IsoP and 5-F(2t)-IsoP, respectively). Whether this formation is relevant clinically remains controversial. The present study was performed in order to evaluate the ability of the isoprostanes 15-F(2t)-IsoP and 5-F(2t)-IsoP to reduce myocardial ischaemic injury in rat isolated heart. 2. Rats were divided into six groups. Hearts were excised, perfused retrogradely and pretreated with vehicle (ethanol 5.10(-7) and 2.10(-9) mol/L; n = 6), subjected to ischaemic preconditioning (n = 8) or pretreated with the isoprostanes 15-F(2t)-IsoP (3.10(-10) and 3.10(-7) mol/L; n = 8) or 5-F(2t)-IsoP (10(-9) mol/L; n = 8). After a 5 min treatment-5 min washout period, hearts were submitted to 30 min global ischaemia, followed by a 120 min reperfusion period. 3. The infarct-to-ventricle zone ratio was significantly reduced in ischaemic preconditioned (20.6 +/- 2.6%) compared with vehicle groups (44.5 +/- 4.3 and 51.3 +/- 2.5% in groups pretreated with 5.10(-7) or 2.10(-9) mol/L ethanol, respectively). Pretreatment with either isoprostane had no cardioprotective effect; the infarct-to-ventricle ratios were 43.1 +/- 2.2, 49.4 +/- 5.9 and 44.5 +/- 5.0% for groups treated with 3.10(-10) mol/L 15-F(2t)-IsoP, 3.10(-7) mol/L 15-F(2t)-IsoP or 10(-9) mol/L 5-F(2t)-IsoP, respectively. 4. These data provide evidence that the isoprostanes 15-F(2t)-IsoP and 5-F(2t)-IsoP are not implicated in early myocardial preconditioning at concentrations similar to those found in the human coronary sinus following coronary angioplasty.

Effects of short-term treatment with vitamin E in systemic sclerosis: a double blind, randomized, controlled clinical trial of efficacy based on urinary isoprostane measurement.

This double blind randomized controlled trial was designed to investigate whether short-term vitamin E treatment at doses of 500 and 1000 mg/day, compared to placebo, decreased urinary F(2)-isoprostanes and improved the microvascular perfusion after cold exposure in patients suffering from SSc. Thirty-three eligible patients were randomly assigned in a 1.3:1:1 ratio to receive placebo, vitamin E 500 mg, or vitamin E 1000 mg daily for 3 weeks. Clinical examination, analysis of plasma vitamin E, urinary F(2)-isoprostane levels and a whole body cooling test were performed at baseline and after a 3-week period of treatment. Urinary 15-F(2t)-IsoP levels and cutaneous blood flow variation in response to cold did not significantly differ before versus after treatment in any group. Furthermore, no difference was found between groups after 3 weeks of treatment. We show that 3-week vitamin E treatment at doses of 500 or 1000 mg/day neither decreases the basal rate of lipid peroxidation nor improves microvascular perfusion after cold exposure. These data does not support the need for phase III clinical trials to test efficacy of vitamin E in SSc.

[Genetic polymorphism and treatment of chronic bowel inflammatory diseases: the example of azathioprine]. / Polymorphisme génétique et traitement des maladies inflammatoires chroniques de l'intestin: exemple de l'azathioprine.

Azathioprine is an immunosuppressive drug used in the treatment of inflammatory bowel disease. It is a prodrug that is hydrolysed to 6-mercaptopurine, which represents the active form. Azathioprine is also used in the treatment of leukaemia in children and in organ transplantation. Azathioprine treatment is associated with adverse effects such as leukopenia and aplasia. These adverse effects are related to a single nucleotide polymorphism, including the inability of cells to synthesize thiopurine methyltransferase (TPMT). TPMT is a detoxification enzyme that limits 6-thioguanine nucleotide production and thereby interferes with normal DNA and RNA synthesis. This review presents the different approaches used for azathioprine therapeutic monitoring in IBD treatment and discusses the discrepancies in recent clinical trials.

2-Arachidonoyl glycerol induces contraction of isolated rat aorta: role of cyclooxygenase-derived products.

OBJECTIVES: Endocannabinoids have been shown to play a role in the regulation of vascular tone. The effects of 2-arachidonoyl glycerol (2-AG) on induced-tone were examined in rat aortic rings in vitro. METHODS: Aortic rings from Wistar Kyoto (WKY) rats were suspended in organ chambers for recording isometric tension development in response to 2-AG. The production of TXA2 in response to 2-AG was also assessed by enzyme immunoassay. RESULTS: In endothelium-intact rings pre-contracted to PGF(2alpha), 2-AG (10 nM-30 microM) induced a biphasic effect: a weak relaxation from 10 nM to 0.1 microM, which turned into a concentration-dependent contraction from 3 to 30 microM. Endothelium-denudation did not change 2-AG-mediated vascular effects. 2-AG-induced contraction was unaffected by both the cannabinoid CB1 receptor antagonist SR141716A (3 microM) and the CB2 receptor antagonist SR144528 (1 microM). In contrast, the anandamine transport inhibitor (AM404, 100 microM) and the amino hydrolase inhibitor (PMSF, 30 microM) attenuated (P<0.05) the contractile response evoked by 2-AG in endothelium-intact and rubbed aortic rings. In addition, the cyclooxygenase inhibitor (indomethacin, 10 microM) and the thromboxane A2 (TXA2) receptor (TP receptor) antagonist GR32191 (0.3 microM) totally abolished the contraction elicited by 2-AG in endothelium-intact and rubbed aortic rings. Challenge of isolated aortic rings with 2-AG (10 microM) evoked a significant increase in TXA2 level (measured as TXB2 level) in endothelium-intact and rubbed aortic rings. CONCLUSION: These data suggested that the contraction elicited by 2-AG resulted from the vascular smooth muscle cell uptake and conversion of 2-AG to constrictor prostanoid TXA2, which in turn caused vasoconstriction through the stimulation of TP receptor.

Inhibition of leukotriene synthesis with MK-886 prevents a rise in blood pressure and reduces noradrenaline-evoked contraction in L-NAME-treated rats.

(1) Long-term treatment of rats with Nomega-nitro-l-arginine methyl ester (l-NAME) induces hypertension associated with inflammatory and vascular changes. Leukotrienes are proinflammatory vasoactive products that are suspected to be involved in the pathogenesis of hypertension. We investigated, in rats chronically treated with l-NAME, the involvement of leukotrienes in the in vivo regulation of blood pressure and the in vitro contraction elicited by noradrenaline in isolated aorta. (2) Rats were randomly assigned to four groups and orally treated for 3 weeks with l-NAME (1 mg ml-1), l-NAME (1 mg ml-1) plus the leukotriene biosynthesis inhibitor MK-886 (0.1 mg ml-1), MK-886 (0.1 mg ml-1) alone or vehicle (Methocel, 0.1%). All the drugs were added to the drinking fluid. (3) The mean arterial blood pressure (MABP) increased significantly in l-NAME-treated rats (173.3+/-9.4 mmHg (n=25)) vs Methocel-treated rats (110.7+/-4.8 mmHg (n=11), P<0.001). Chronic treatment with MK-886 prevented this rise in MABP. (4) Aortic rings with or without endothelium were suspended in organ baths for recording isometric changes in response to noradrenaline. Pretreatment with either MK-886 (10 microm), the CysLT1 receptor antagonist MK571 (1 microm) or the dual CysLT1/CysLT2 receptor antagonist BAY-u9773 (0.1 microm) reduced (P<0.05) noradrenaline-induced contractions in intact aortic rings from l-NAME-treated rats only. (5) Noradrenaline (0.3 microm) induced a two-fold increase in cysteinyl leukotriene (CysLT) release (measured by enzyme immunoassay) in intact aortic rings from l-NAME-treated rats only. (6) These data suggested (1) a role for the 5-lipoxygenase pathway in the regulation of blood pressure in l-NAME-treated rats and (2) the involvement of endothelial CysLTs in noradrenaline-induced contraction in aorta from l-NAME-treated rats.

Functional comparison of the antagonistic properties of some Angiotensin II type 1 receptor blockers on the contraction elicited by Angiotensin II and thromboxane A2 on human saphenous veins.

We previously described on human vascular preparations that, in addition to its antagonistic properties on Angiotensin II type 1 (AT1) receptor, losartan could also inhibit the contraction elicited by the stable thromboxane A2 mimetic U46619. The present study was designed (1) to investigate, in human vascular preparations (the saphenous veins) whether these antagonistic properties on thromboxane A2/prostaglandin H2 (TP) receptor were shared by some other AT1 receptor antagonists (irbesartan and valsartan) and the active metabolite of losartan EXP3174, and (2) to compare their antagonistic properties on TP receptors to their antagonistic properties on AT1 receptors. In the presence of indomethacin (10 microM) and Nomega-nitro-L-arginine (100 microM), irbesartan, valsartan, and EXP3174 induced a rightward shift of U46619- and angiotensin II-induced contraction. The inhibitory effect of irbesartan, valsartan, and EXP3174 on U46619-induced contraction was significant from 100 microM while their inhibitory effect on the contraction elicited by angiotensin II was significant from 1 nM. With regard to the plasma therapeutic concentrations of irbesartan, valsartan, and EXP3174, these data suggest that TP receptor blockade does not account for the antihypertensive effects of these AT1 receptor blockers.

Lipid peroxidation is not increased in patients with untreated mild-to-moderate hypertension.

In contrast with the huge amount of experimental data available, only few and somewhat unconvincing clinical studies support the hypothesis that oxidative stress is involved in the early stages of essential hypertension in humans. Isoprostanes are chemically stable lipid peroxidation products of arachidonic acid, the quantification of which provides a novel approach to the assessment of oxidative stress in vivo. The main objective of this study was to quantify the urinary levels of 15-F(2t)-IsoP in the early stages of essential hypertension, using gas chromatography/mass spectrometry, by comparing 30 patients with never-treated mild-to-moderate hypertension with 30 gender- and age-paired healthy controls. Urinary 15-F(2t)-IsoP levels were not significantly different in hypertensive patients (69+/-36 pmol/mmol creatinine) compared with controls (75+/-34 pmol/mmol creatinine, 95% confidence intervals on differences: -23 to 13). No significant correlation was found between basal urinary 15-F(2t)-IsoP levels and age, low-density lipoprotein cholesterol, glucose, clinical pulse pressure, carotid intima-media thickness, left ventricular mass index, or aortic pulse wave velocity. In conclusion, this study shows that lipid peroxidation is not increased in never-treated mild-to-moderate hypertension. This suggests that oxidative stress is not implicated in the pathogenesis of human essential hypertension, at least in the early stages.

Ribavirin quantification in combination treatment of chronic hepatitis C.

Ribavirin in combination with alpha 2 interferon is the consensus treatment for chronic hepatitis C. However, recent preliminary pharmacological studies have suggested that the bioavailability of ribavirin displays great interindividual variability. In order to monitor serum ribavirin levels during combination treatment, we developed and validated a quantitative assay using an approach adaptable for routine hospital laboratories. The method involved solid-phase extraction on phenyl boronic acid cartridges followed by high-performance liquid chromatography with a C(18)-bonded silica column and a mobile phase containing 10 mM ammonium phosphate buffer (with the pH adjusted to 2.5) and UV detection (207 nm). The sensitivity, recovery, linearity of the calibration curve, intra- and interassay accuracies, precision, and stability at 4 degrees C were consistent with its use in the laboratory routine. In addition, other nucleoside analogues sometimes used with ribavirin in patients coinfected with hepatitis C virus (HCV) and human immunodeficiency virus did not interfere with the quantification of ribavirin levels. The ribavirin concentration was quantified in 24 serum samples from patients with chronic hepatitis C treated with a combination of ribavirin and alpha 2 interferon. The mean serum ribavirin concentration was 2.67 +/- 1.06 micro g/ml (n = 24) at week 12 of treatment (W12) and 3.24 +/- 1.35 micro g/ml (n = 24) at week 24 of treatment (W24). In addition, ribavirin concentrations displayed high interindividual variabilities: the coefficients of variation of the serum ribavirin concentrations adjusted to the administered dose were 44 and 48% at W12 and W24, respectively. Moreover, the ribavirin concentration was higher in patients with a sustained virological response (n = 11) than in patients with treatment failure (n = 13), with significant intergroup differences at W12 (P = 0.030) and W24 (P = 0.049). The present study describes a simple analytical method for the quantification of ribavirin in human serum that could be a useful tool for the monitoring of ribavirin concentrations in HCV-infected patients in order to improve the efficacy and safety of therapy with ribavirin plus interferon.

Isoprostanes as a biomarker of lipid peroxidation in humans: physiology, pharmacology and clinical implications.

Isoprostanes are a complex family of compounds produced from arachidonic acid via a free-radical-catalyzed mechanism. They can be quantified as reliable markers of lipid peroxidation. Among the isoprostanes, 15-F(2t)-IsoP and 15-E(2t)-IsoP are biologically active and mediate vasoconstriction and bronchoconstriction and augment nociception. These effects are thought to be mediated via the activation of prostanoid TP receptors, with isoprostanes acting as full or partial agonists. A strong link between lipid peroxidation and diseases associated with ischaemia-reperfusion, atherosclerosis and inflammation has been suggested by elevated levels of F(2)-isoprostanes observed in such diseases. Thus, quantification of F(2)-isoprostanes as a pathophysiological marker provides a unique opportunity to investigate lipid peroxidation in human diseases and provides an interesting biomarker for rational dose selection of antioxidants in diseases where oxidative stress might be involved.

Effects of modafinil on heat thermoregulatory responses in humans at rest.

The effects of modafinil on heat thermoregulatory responses were studied in 10 male subjects submitted to a sweating test after taking 200 mg of modafinil or placebo. Sweating tests were performed in a hot climatic chamber (45 degrees C, relative humidity <15%, wind speed = 0.8 m x s(-1), duration 1.5 h). Body temperatures (rectal (Tre) and 10 skin temperatures (Tsk)), sweat rate, and metabolic heat production (M) were studied as well as heart rate (HR). Results showed that modafinil induced at the end of the sweating test higher body temperatures increases (0.50 +/- 0.04 versus 0.24 +/- 0.05 degrees C (P < 0.01) for deltaTre and 3.64 +/- 0.16 versus 3.32 +/- 0.16 degrees C (P < 0.05) for deltaTsk (mean skin temperature)) and a decrease in sweating rate throughout the heat exposure (P < 0.05) without change in M, leading to a higher body heat storage (P < 0.05). AHR was also increased, especially at the end of the sweating test (17.95 +/- 1.49 versus 12.52 +/- 1.24 beats/min (P < 0.01)). In conclusion, modafinil induced a slight hyperthermic effect during passive dry heat exposure related to a lower sweat rate, probably by its action on the central nervous system, and this could impair heat tolerance.

Increased urinary F2-isoprostanes in systemic sclerosis, but not in primary Raynaud's phenomenon: effect of cold exposure.

OBJECTIVE: F2-isoprostanes are free radical-dependent arachidonic acid metabolites that are used as clinical markers of lipid peroxidation in systemic sclerosis (SSc) and other microvascular diseases. The objectives of this study were to determine whether the basal urinary levels of F2-isoprostane in SSc patients differ from those in patients with primary Raynaud's phenomenon (RP) and to investigate whether F2-isoprostane formation correlates with the cutaneous microvascular perfusion decrease following cold exposure in SSc patients, patients with primary RP, and healthy controls. METHODS: Eleven women with RP secondary to SSc, 11 women with primary RP, and 11 healthy women were exposed to decreasing room temperature, from 25 degrees C to 15 degrees C, for 40 minutes. Urine samples were obtained before and after the test for gas chromatography/electronic impact mass spectrometry quantification of 15-F(2t)-isoprostane (15-F(2t)-IsoP; also called isoprostaglandin F(2alpha) type III). Cutaneous blood flow was monitored using a laser Doppler perfusion imager. RESULTS: The mean +/- SEM urinary 15-F(2t)-IsoP levels at baseline in SSc patients (178 +/- 32 pmoles/mmole of creatinine) were 1.9 times higher than those in healthy controls (95 +/- 11 pmoles/mmole of creatinine) and 1.7 times higher than those in patients with primary RP (107 +/- 19 pmoles/mmole of creatinine) (P < 0.05 for controls and patients with primary RP versus SSc patients). No significant correlation was found between basal urinary 15-F(2t)-IsoP levels and the temperature or cutaneous blood flow decrease in response to the whole-body cooling. Furthermore, the 15-F(2t)-IsoP response to the cooling test was not correlated with the cutaneous blood flow decrease. CONCLUSION: Lipid peroxidation is increased in SSc patients, but not in patients with primary RP. Cold exposure leads to a significant but small increase in 15-F(2t)-IsoP levels that is independent of the cutaneous blood flow decrease. F2-isoprostane quantification may be an interesting pharmacologic tool for monitoring responses to antioxidant treatment in SSc patients.