Learning condyle repositioning during orthognathic surgery with a surgical navigation system

Condyle repositioning during bilateral sagittal splint osteotomy (BSSO) is a challenging step for the inexperienced surgeon. We aimed to demonstrate the benefit of navigation for learning the condyle repositioning. We treated 100 patients who underwent a BSSO. A trainee performed the condyle repositioning of one side in two phases. In the first one, the trainee positioned without watching the screen of the Orthopilot Navigation system (ONS). In the second one, the trainee could use the ONS to replace the condyle. Heuristic, anatomical and functional scores of each phase were recorded. Heuristic (17% vs. 75%; p<0.0001), anatomical (35% vs. 86%; p<0.0001) and functional (14% vs. 56%; p<0.0001) scores were significantly greater with the ONS. The ONS is a promising and original intraoperative learning tool for the repositioning of the condyle during BSSO.

Chronic vagus nerve stimulation in Crohn's disease: a 6-month follow-up pilot study

The vagus nerve (VN) is a link between the brain and the gut. The VN is a mixed nerve with anti-inflammatory properties through the activation of the hypothalamic-pituitary-adrenal axis by its afferents and by activating the cholinergic anti-inflammatory pathway through its efferents. We have previously shown that VN stimulation (VNS) improves colitis in rats and that the vagal tone is blunted in Crohn's disease (CD) patients. We thus performed a pilot study of chronic VNS in patients with active CD. Seven patients under VNS were followed up for 6 months with a primary endpoint to induce clinical remission and a secondary endpoint to induce biological (CRP and/or fecal calprotectin) and endoscopic remission and to restore vagal tone (heart rate variability). Vagus nerve stimulation was feasible and well-tolerated in all patients. Among the seven patients, two were removed from the study at 3 months for clinical worsening and five evolved toward clinical, biological, and endoscopic remission with a restored vagal tone. These results provide the first evidence that VNS is feasible and appears as an effective tool in the treatment of active CD.

Abnormal amplitude and kinetics of digital postocclusive reactive hyperemia in systemic sclerosis

OBJECTIVES

Postocclusive reactive hyperemia is mediated by two major mediators: sensory nerves and endothelium-derived hyperpolarizing factors. We hypothesized that the skin microvascular response to 5 min ischemia would differ depending upon the hand location in patients with systemic sclerosis (SSc), primary Raynaud's phenomenon (PRP) and healthy controls.

METHODS

Fifteen patients with SSc, 15 sex- and age-matched patients with PRP and healthy controls were enrolled. Their right hands were subjected to 5 min ischemia followed by a postocclusive hyperemia test, with local microcirculation monitoring by laser speckle contrast imaging on the dorsal face of the hand.

RESULTS

Postocclusive reactive hyperemia was abnormal in terms of peak and area under the curve (AUC) on all fingers except the thumb in patients with SSc and PRP compared with controls. In contrast, the kinetics of the response was longer only in SSc patients, with mean (SD) time to peak on the index, middle and ring finger were respectively 72 (58), 73 (51) and 67 (47) s for SSc; 40 (20), 40 (20) and 36 (19) s for PRP; and 34 (30), 34 (30) and 29 (24) s for controls (P=0.009 for interaction).

CONCLUSIONS

We observed decreased distal digital microvascular perfusion following 5 min of ischemia in patients presenting with PRP or SSc, while the kinetics was prolonged only in SSc. A dynamic assessment of digital skin blood flow using laser speckle contrast imaging following 5 min ischemia could be used as a tool to assess microvascular abnormalities in patients with Raynaud's phenomenon secondary to SSc.

Skin microdialysis coupled with laser speckle contrast imaging to assess microvascular reactivity

OBJECTIVE

Laser speckle contrast imaging (LSCI) can be used to assess real-time responses of skin microcirculation to pharmacological interventions. The main objective of this study was to determine whether intradermal or subdermal microdialysis fiber insertion, coupled with skin flux recording using LSCI, can be used to assess baseline cutaneous flux and the post-occlusive reactive hyperemic response. The microdialysis sites were compared to control area without microdialysis fibers.

METHODS

One dermal and two subdermal microdialysis fibers were randomly inserted in the right forearm skin of six healthy volunteers. We performed consecutively tests of post-occlusive hyperemia, infusion of 29 mM sodium nitroprusside (SNP), local thermal hyperemia at 43°C and a second 29 mM SNP infusion at the end of the experiment.

RESULTS

Two hours after fiber insertion, cutaneous vascular conductances (CVC) at the subdermal fiber sites were not different from their respective control regions of interest, while at the dermal site CVC remained higher (0.48+/-0.15 versus 0.37+/-0.1 PU.mm Hg(-1), P=0.003). The peak CVC and area under the curve observed during post-occlusive reactive hyperemia were similar at all fiber sites and their respective controls. We observed a similar increase in CVC using 29 mM SNP infusion, 40 min local heating at 43°C, and their combination. Finally, physiological and pharmacological responses of the subdermal sites were reproducible in terms of amplitude, whether expressed as raw CVC or as % CVCmax.

CONCLUSIONS

We showed that studying skin microvascular physiological or pharmacological responses using inserted subdermal microdialysis fibers coupled with LSCI is feasible and reproducible, and provides two-dimensional information. This technique will be useful for future mechanistic studies of skin microcirculation.

Cathodal iontophoresis of treprostinil and iloprost induces a sustained increase in cutaneous flux in rats

BACKGROUND AND PURPOSE

The treatment of scleroderma-related digital ulcers is still a therapeutic challenge. The most effective drugs are prostacyclin analogues. However, their usage is limited to an intravenous route of administration and by their frequent side effects. The objective of this study was to test whether treprostinil, iloprost and epoprostenol can induce sustained vasodilatation in rats when delivered locally using cutaneous iontophoresis.

EXPERIMENTAL APPROACH

Treprostinil, iloprost and epoprostenol were delivered by cathodal and anodal iontophoresis onto the hindquarters of anaesthesized rats (n= 8 for each group). Skin blood flow was quantified using laser Doppler imaging and cutaneous tolerance was assessed from day 0 to day 3.

KEY RESULTS

Cathodal but not anodal iontophoresis of treprostinil (6.4 mM), iloprost (0.2 mM) and epoprostenol (1.4 mM) induced a significant and sustained increase in cutaneous blood flow. The effects of treprostinil and iloprost were significantly different from those of treprostinil vehicle. Only weak effects were observed when both drugs were applied locally without current. Skin resistance was unchanged in areas treated with prostacyclin analogues. Finally, skin tolerance was good, with no evidence of epidermal damage.

CONCLUSIONS AND IMPLICATIONS

Cathodal iontophoresis of treprostinil and iloprost increases cutaneous blood flow with a good local tolerance. The effects of cathodal iontophoresis of these drugs should be investigated in humans, as they could have potential as new local therapies for digital ulcers in patients with scleroderma.

NLRP1 influences the systemic sclerosis phenotype: a new clue for the contribution of innate immunity in systemic sclerosis-related fibrosing alveolitis pathogenesis

BACKGROUND

Recent evidence has highlighted a potential role of interleukin 1β (IL-1β) in systemic sclerosis (SSc). NLRP1 provides a scaffold for the assembly of the inflammasome that promotes the processing and maturation of pro-IL-1β. In addition, NLRP1 variants were found to confer susceptibility to autoimmune disorders.

OBJECTIVE

/st> To study a possible association of the NLRP1 rs6502867, rs2670660 and rs8182352, rs12150220 and rs4790797 with SSc in the European Caucasian population.

METHODS

NLRP1 single nucleotide polymorphisms were genotyped in 3227 individuals comprising a discovery set (870 SSc patients and 962 controls) and a replication set including individuals from Germany (532 SSc patients and 324 controls) and Italy (527 SSc patients and 301 controls), all individuals being of European Caucasian origin.

RESULTS

Conditional analyses revealed a significant association for the NLRP1 rs8182352 variant with both anti-topoisomerase-positive and SSc-related fibrosing alveolitis (FA) subsets under an additive model: p=0.0042, OR 1.23 (95% CI 1.07 to 1.41) and p=0.0065 OR 1.19 (95% CI 1.05 to 1.36), respectively. Logistic regression analysis showed an additive effect of IRF5 rs2004640, STAT4 rs7574865 and NLRP1 rs8182352 risk alleles on SSc-related FA.

CONCLUSIONS

Our results establish NLRP1 as a new genetic susceptibility factor for SSc-related pulmonary fibrosis and anti-topoisomerase-positive SSc phenotypes. This provides new insights into the pathogenesis of SSc, underlining the potential role of innate immunity in particular in the FA-positive SSc subphenotype, which represents a severe subset of the disease.

Oral sildenafil increases skin hyperaemia induced by iontophoresis of sodium nitroprusside in healthy volunteers

BACKGROUND AND PURPOSE

Sildenafil, a specific inhibitor of phosphodiesterase 5A (PDE5A), is currently tested as a treatment for severe Raynaud's phenomenon. Here, we tested whether sildenafil, alone or combined with local sodium nitroprusside (SNP) delivered through skin iontophoresis, increased forearm cutaneous blood conductance in healthy volunteers, and to assess how well this combination was tolerated.

EXPERIMENTAL APPROACH

Ten healthy volunteers were enrolled. Variations in cutaneous vascular conductance (CVC) following oral administration of 50 or 100 mg of sildenafil with or without SNP iontophoresis were expressed as a percentage of maximal CVC, and were monitored using laser Doppler imaging. SNP iontophoresis was performed on the ventral surface of the forearm, 1 h after application of lidocaine/prilocaine cream.

KEY RESULTS

Sildenafil at 100 mg, but not 50 mg, increased overall responses (area under the curve) (44%) and peak responses (29%) to SNP iontophoresis. Sildenafil at 100 mg, but not 50 mg, increased baseline CVC (75%). Incidence of headache was not changed when SNP iontophoresis was combined with sildenafil. One episode of symptomatic arterial hypotension occurred in a volunteer given 50 mg sildenafil, 30 min after the beginning of SNP iontophoresis.

CONCLUSIONS AND IMPLICATIONS

Oral sildenafil at 100 mg potentiated local skin hyperaemia induced by SNP iontophoresis, with no increased incidence of headaches. The combination of oral specific PDE5A inhibitor and nitrates administered through skin iontophoresis deserves further investigation in diseases such as severe Raynaud's phenomenon, with particular attention to the incidence of arterial hypotension.

Association of the TNFAIP3 rs5029939 variant with systemic sclerosis in the European Caucasian population

BACKGROUND

TNFAIP3 encodes the ubiquitin-modifying enzyme, a key regulator of inflammatory signalling pathways. Convincing associations between TNFAIP3 variants and autoimmune diseases have been reported.

OBJECTIVE

To investigate the association of TNFAIP3 polymorphisms with systemic sclerosis (SSc).

METHODS

Three single nucleotide polymorphisms (SNPs) in a set of 1018 patients with SSc and 1012 controls of French Caucasian origin were genotyped. Two intergenic SNPs, rs10499194 and rs6920220, and one located in TNFAIP3 intron 2, rs5029939, were selected. The TNFAIP3 rs5029939 found to be associated with SSc in this first set was then genotyped in a second set of 465 patients with SSc and 182 controls from Germany and 184 patients with SSc and 124 controls from Italy. Pooled odd ratios were calculated by Mantel-Haenszel meta-analysis.

RESULTS

The rs5029939 G allele was found to be significantly associated with SSc susceptibility (pooled OR=2.08 (95% CI 1.59 to 2.72); p=1.16×10⁻⁷), whereas the rs10499194 and rs6920220 variants displayed no association. Only one of the predicted haplotypes investigated in the French sample was significantly associated with SSc (p=8.91×10⁻⁸), and this haplotype was discriminating only in the presence of the rs5029939 risk allele, suggesting that this SNP tags the association signal. The strongest associations of rs5029939 with subphenotypes, having large magnitudes for complex genetic disorders, were observed for diffuse cutaneous SSc (pooled OR=2.71 (1.94 to 3.79), p=5.2×10⁻⁹), fibrosing alveolitis (pooled OR=2.26 (1.61 to 3.17), p=2.5×10⁻⁶) and pulmonary arterial hypertension (pooled OR=3.11 (1.86 to 5.17), p=1.3×10⁻⁵).

CONCLUSION

These results suggest that TNFAIP3 is a genetic susceptibility factor for SSc.

Reproducibility of a local cooling test to assess microvascular function in human skin

OBJECTIVE

In the present study we aimed to assess the reproducibility of skin microvascular reactivity while fast cooling locally with a custom-designed laser-Doppler flowmetry (LDF) probe.

METHODS

Twenty-two healthy volunteers underwent local 15 degrees C cooling on the forearm during 5 (protocol 1, n=12) or 30 min (protocol 2, n=10). Skin blood flow was concomitantly assessed using LDF. Measurements were repeated after 30 min (protocol 1) or 7 days (protocols 1 and 2). Data were expressed as cutaneous vascular conductance (CVC) and percentage of baseline (%BL). Within subject coefficients of variation (CV) and intra-class correlation coefficients (ICC) were calculated.

RESULTS

Immediate reproducibility of the 5-min cooling was very good, either expressed as CVC or %BL (CV were 8% and 18%; ICC were 0.85 and 0.78, respectively). However, the 30-min cooling was the most reproducible at 1 week, either as CVC or %BL (CV were 26% and 23%; ICC were 0.86 and 0.75, respectively). Local cooling was well tolerated by all volunteers.

CONCLUSIONS

We propose in the present work a reproducible 30-min LDF cooling test. Such a tool could be of great interest to assess microvascular reactivity to local cooling in diseases such as Raynaud's syndrome, and to further evaluate drugs for such diseases.

Association between the IRF5 rs2004640 functional polymorphism and systemic sclerosis: a new perspective for pulmonary fibrosis

OBJECTIVE

There is now growing evidence that connective tissue diseases, including systemic sclerosis (SSc), share a common genetic background. Microarray studies support a pivotal role of type I interferon (IFN) in the pathophysiology of connective tissue diseases. Interferon regulatory factors coordinate the expression of type I IFNs, and the IRF5 gene has been identified as a susceptibility gene of systemic lupus and Sjögren's syndrome. The aim of this study was to determine whether the IRF5 rs2004640 single-nucleotide polymorphism is associated with SSc.

METHODS

The IRF5 rs2004640 (GT) functional polymorphism was genotyped in 1,641 subjects of French European Caucasian origin: a discovery set comprising 427 patients with SSc and 380 control subjects and a replication set comprising 454 patients with SSc and 380 control subjects.

RESULTS

In both the discovery set and the replication set, the TT genotype was significantly more common in patients with SSc than in control subjects, with an odds ratio (OR) for the combined populations of 1.58 (95% confidence interval [95% CI] 1.18-2.11 [P for trend 0.002]). Analyses of the whole SSc population showed a significant association between homozygosity for the T allele and the presence of antinuclear antibodies (corrected P [Pcorr]=0.04, OR 1.59, 95% CI 1.16-2.17) and fibrosing alveolitis (Pcorr=0.001, OR 2.07, 95% CI 1.38-3.11). In a multivariate analysis model including the diffuse cutaneous subtype of SSc and positivity for anti-topoisomerase I antibodies, the IRF5 rs2004640 TT genotype remained associated with fibrosing alveolitis (P=0.029, OR 1.92, 95% CI 1.07-3.44).

CONCLUSION

The IRF5 rs2004640 GT substitution is associated with susceptibility to SSc. These data provide new insight into the pathogenesis of SSc, including clues to the mechanisms leading to fibrosing alveolitis.

Myocardial infarction and Turner's syndrome

This paper reports the case of a patient with Turner's syndrome, who developed a myocardial infarction at the age of 36. Turner's syndrome, associated with gonadal insufficiency, increases atherosclerotic cardiovascular risks that must be assessed during the patient's follow-up.

Thrombolysis of mobile right atrial thrombi following severe pulmonary embolism

Thrombolysis may favorably affect the clinical outcome of mobile right atrial thrombus following pulmonary embolism (PE). We report the case of three patients with mobile right atrial thrombus following PE, in whom fibrinolysis was performed. Atrial mass disappeared on the control echocardiogram, but control ventilation perfusion scan showed new perfusion defects in all patients. Thrombolysis seems successful for the treatment of patients with mobile right atrial thrombus following PE; however, recurrent PE may be induced by fibrinolysis. This may affect the benefit of such therapy and should be taken into account when using this therapeutic treatment.

Effect of homeopathy on analgesic intake following knee ligament reconstruction: a phase III monocentre randomized placebo controlled study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

The efficacy of homeopathy is still under debate and a recent meta-analysis recommended further randomized double-blind clinical trials to identify any clinical situation in which homeopathy might be effective.

WHAT THIS STUDY ADDS

The complex of homeopathy tested in this study (Arnica montana 5 CH, Bryonia alba 5 CH, Hypericum perforatum 5 CH and Ruta graveolens 3 DH) is not superior to placebo in reducing 24 h morphine consumption after knee ligament reconstruction.

AIMS

The efficacy of homeopathy is still under debate. The objective of this study was to assess the efficacy of homeopathic treatment (Arnica montana 5 CH, Bryonia alba 5 CH, Hypericum perforatum 5 CH and Ruta graveolens 3 DH) on cumulated morphine intake delivered by PCA over 24 h after knee ligament reconstruction.

METHODS

This was an add-on randomized controlled study with three parallel groups: a double-blind homeopathic or placebo arm and an open-label noninterventional control arm. Eligible patients were 18-60 years old candidates for surgery of the anterior cruciate ligament. Treatment was administered the evening before surgery and continued for 3 days. The primary end-point was cumulated morphine intake delivered by PCA during the first 24 h inferior or superior/equal to 10 mg day(-1).

RESULTS

One hundred and fifty-eight patients were randomized (66 in the placebo arm, 67 in the homeopathic arm and 25 in the noninterventional group). There was no difference between the treated and the placebo group for primary end-point (mean (95% CI) 48% (35.8, 56.3), and 56% (43.7, 68.3), required less than 10 mg day(-1) of morphine in each group, respectively). The homeopathy treatment had no effect on morphine intake between 24 and 72 h or on the visual analogue pain scale, or on quality of life assessed by the SF-36 questionnaire. In addition, these parameters were not different in patients enrolled in the open-label noninterventional control arm.

CONCLUSIONS

The complex of homeopathy tested in this study was not superior to placebo in reducing 24 h morphine consumption after knee ligament reconstruction.

Analyse spectrale par transformée de Fourier du flux sanguin cutané dans la sclérodermie systémique

OBJECTIVES

Endothelial dysfunction is an early event and a critical step in the pathogenesis of systemic sclerosis. Accurate and sensitive tests are needed to correctly assess the degree of microvascular endothelial dysfunction. Spectral analysis of skin blood flow contains a characteristic low frequency reported to be associated with endothelial function in healthy subjects. We hypothesized that the relative amplitude of the oscillation recorded for this low frequency spectrum (0.008 to 0.021 Hz) would be less pronounced in patients with systemic sclerosis than in healthy subjects and in patients with primary Raynaud's phenomenon.

PATIENTS AND METHOD

Twenty-one patients with systemic sclerosis, twenty patients with primary Raynaud phenomenon and eleven healthy subjects were enrolled. Skin perfusion was recorded at rest for 30 minutes using laser Doppler flowmetry on the pad of the left third left. Fourier transform spectral analysis was applied to obtain the mean amplitude of the cutaneous blood perfusion signal of the total spectrum from 0.008 to 1.6 Hz and the mean amplitude of each characteristic frequency in the laser Doppler flowmeter blood flow oscillations.

RESULTS

The relative amplitudes of each characteristic frequency in the laser Doppler flowmeter blood flow oscillations were not statistically different in the three groups, particularly for frequency spectrum from 0.008 Hz to 0.021 Hz.

CONCLUSION

Fourier transform spectral analysis of baseline cutaneous blood flow does not provide significant information. Further studies are required, perhaps using wavelet spectral analysis or stimulated conditions.

Evaluation of cardiac abnormalities by Doppler echocardiography in a large nationwide multicentric cohort of patients with systemic sclerosis

OBJECTIVES

There is increasing concern about heart and pulmonary vascular involvement in systemic sclerosis (SSc). One of the most severe complications of SSc is pulmonary arterial hypertension (PAH). There has been an increased awareness of left ventricular (LV) diastolic abnormalities in SSc patients. However, previous studies have generally been conducted in small populations. The aims of this study were to prospectively screen for PAH and to describe echocardiographic parameters in a large group of SSc patients.

METHODS

This prospective study was conducted in 21 centres for SSc in France. Patients without severe pulmonary function abnormalities, severe cardiac disease and known PAH underwent Doppler echocardiography performed by a reference cardiologist.

RESULTS

Of the 570 patients evaluated, PAH was suspected in 33 patients and was confirmed in 18 by right heart catheterisation. LV systolic dysfunction was rare (1.4%). LV hypertrophy was found in 22.6%, with LV diastolic dysfunction in 17.7%. These LV abnormalities were influenced by age, gender and blood pressure. We identified a small group of 21 patients with a restrictive mitral flow pattern in the absence of any other cardiopulmonary diseases, suggesting a specific cardiac involvement in SSc.

CONCLUSIONS

Left and right heart diseases, including PAH, LV hypertrophy and diastolic dysfunction, are common in SSc. However, a small subset of patients without any cardiac or pulmonary diseases have a restrictive mitral flow pattern that could be due to primary cardiac involvement of SSc. The prognostic implications of the LV abnormalities will be evaluated in the 3-year follow-up of this cohort.

Digital thermal hyperaemia impairment does not relate to skin fibrosis or macrovascular disease in systemic sclerosis

OBJECTIVES

Thermal hyperaemia is impaired in patients with systemic sclerosis (SSc). The objective of these studies was to determine whether this was consecutive to skin fibrosis, microangiopathy or macroangiopathy.

METHODS

Using laser Doppler flowmetry, we first compared the thermal hyperaemia on the third left finger pad and on the left forearm in 21 patients with non-diffuse systemic sclerosis (SSc), in comparison with primary Raynaud's phenomenon and healthy volunteers. Second, we tested whether the altered thermal hyperaemia correlated to the digital pressure index at baseline, and following the thermal challenge.

RESULTS

In the first study, thermal hyperaemia of the finger pad was impaired in terms of both amplitude and kinetics, but not on the forearm in patients with SSc. In the seven SSc patients without cutaneous fibrosis, the response was similarly altered in terms of amplitude and kinetics. In the second study, we observed a weak correlation between the digital systolic blood pressure index. However, in the 15 SSc patients tested at 44 degrees C, the median digital systolic blood pressure index was 1.04 (0.84-1.24) at baseline vs 1.08 (0.87-1.29) at 44 degrees C (NS), while seven of them had an abnormal response in terms of kinetic. Furthermore, only one patient showed a clear-cut decrease in digital systolic blood pressure at 44 degrees C.

CONCLUSION

In patients with SSc, digital thermal hyperaemia is impaired, but does not relate to the skin fibrosis or to an associated macroangiopathy in most cases. Further studies are required to determine whether its impairment reflects a functional or structural microvascular damage.

Les isoprostanes, biomarqueurs de peroxydation lipidique chez l'homme. Partie 3 : biomarqueurs et médiateurs en physiologie et pathologie vasculaire

The 15-series F(2)-isoprostanes mediate vasoconstriction in different vascular beds and species. This contraction is mediated by the thromboxane receptors stimulation, and may be modulated by the endothelium. Furthermore, 15-F(2t)-IsoP induces smooth muscle cells mitogenesis and monocyte adhesion to endothelial cells. Some 15-series E(2)-isoprostanes are more potent than F(2)-isoprostanes. In clinical studies, 15-F(2t)-IsoP levels are increased in vascular disorders involving atherosclerosis, ischemia-reperfusion and inflammation. F(2)-isoprostane levels correlate to the severity of heart failure and pulmonary hypertension, raising the potential prognostic interest of these biomarkers. Whether the effects observed in vitro are observed consistently in vivo at physiological concentrations and whether these effects contribute to pathological states in vivo is still debated.

Les isoprostanes, biomarqueurs de peroxydation lipidique chez l'homme. Partie 1. Nomenclature et synthèse

The synthesis of prostaglandins has been a subject of chemical attractiveness for the last 40 years with the successful strategy developed by Corey et al. via a formyl-lactone in the trans-PG series, derived from the action of cyclooxygenases (COXs). The non-enzymatic metabolic scheme of arachidonic acid, as a free radical catalyzed mechanism, has introduced new data concerning the reactivity of the arachidonyl radical in the absence of COXs and also a growing interest in the total synthesis of isoprostanes and analogues. The potent biological activity of these compounds has been attracting intense research interest since they were detected in humans as well as animal models in the early 1990s. The measurement of these isoprostanes has been regarded as one of the most useful non-invasive biomarkers for oxidative stress status. Two mechanisms for their biosynthesis have been proposed. In the first mechanism, a peroxyl radical undergoes successive 5-exo cyclizations analogous to the enzymatic mechanism proposed for prostaglandin biosynthesis. The second mechanism starts with a 4-exo cyclization of a peroxyl radical leading to an intermediate dioxetane. During the last two decades, several approaches towards the synthesis of isoprostanes and analogues have been reported in the literature by several groups of chemists. Finally, to date, two nomenclatures have been proposed by Taber et al. and Rokach et al., but only Taber's nomenclature have been approved by IUPAC.

Les isoprostanes, biomarqueurs de peroxydation lipidique chez l'homme. Partie 2 : méthodes de quantification

The isoprostanes are a new class of natural products produced in vivo by a non-enzymatic free-radical-induced peroxidation of polyunsaturated fatty acids. The quantification of these compounds represents a reliable and useful index of lipid peroxidation and oxidant stress in vivo. Then, a large amount of works has been done in the field of isoprostane analysis, but till now, no standardized method seems to emerge. Indeed, described methodologies differ either in the sample preparation steps or in the detection techniques or both. Extraction and purification procedures are often critical and time-consuming, requiring successive chromatographic steps and these procedures lead to a substantial loose of target compounds. Moreover, two main analytical approaches have been adopted for IsoP measurement: immunological methods or mass spectrometry. Some discussion about the methodology used for measurement of isoprostane is important. This review will aim to present and compare different methods developed nowadays for extraction, purification and analysis of F(2)-iPs in various biological samples.

[Biomarkers as prognostic factors in pulmonary arterial hypertension. Rationale and study design]

CURRENT SITUATION

Pulmonary arterial hypertension (PAH) is a serious disease. Its prognostic is based on the functional status quantified by the NYHA class and the 6-min walking test, and the hemodynamic data. The algorithms of treatment are solely based on the hemodynamic data and the functional status. The main objective is to test whether basal concentrations of isoprostanes, Big endotheline 1, ADMA, high sensitivity CRP, NT-Pro-BNP and cardiac troponin T are a 3-year prognostic factor in PAH using a combined criterion: death from any cause and pulmonary or cardiopulmonary transplantation.

MATERIALS AND METHODS

This is a multicenter, prospective, prognostic, single blinded study (plasma and urinary samples being blinded). The study started in november 2003, running for 2 years, with a 3 year follow-up for each patient. The main inclusion criterion is PAH. The data analysis will use a multivariable Cox model, taking into account the functional and hemodynamic parameters.

EXPECTED RESULTS

This study will determine whether any of the biomarkers tested provides additional prognostic information in PAH in addition to the functional and hemodynamic parameters.

[Readability of informed consent forms for subjects participating in biomedical research: updating is required]

OBJECTIVE

We compared informed consent forms of subjects participating in biomedical research with those of references texts in order to determine the factors that influence readability.

METHODS

We assessed the readability of 73 informed consent forms of research protocols conducted in the clinical investigation centres in the Rhone-Alpes area, and then compared them with 33 reference texts corresponding to 5 French school grades (first year infant, primary school, GCS level, high school, and classics aggregation), using the Flesch test and Cordial" analyser.

RESULTS

Median Flesch scores were 66 for the first year infant level, 62 for the primary school level, 58 for the GCS level, 42 for the high school level, and 43 for the aggregation level. It was 22 for the informed consent forms. Median Cordial scores were 86 for the first year infant level, 77 for the second, 74 for the third, 49 for the fourth, 43 for the fifth. It was 1 for the informed consent forms. No methodological factor correlated with Flesch and Cordial" results.

CONCLUSION

The quantitative readability scores for informed consent forms for subjects participating in biomedical research are low, lower than those proposed to aggregation candidates, whatever the type of protocol. Some thought must be given to the impact of the reduced readability on patients' understanding, and steps should be taken to improve the readability of the forms.

Les isoprostanes : un rôle physiopathologique potentiel en pathologie vasculaire

PURPOSE

Isoprostanes are arachidonic acid metabolites produced by a free-radical-dependent mechanism.

CURRENT KNOWLEDGE AND KEY POINTS

The 15-series F2-isoprostanes and some 15-series E2-isoprostanes mediate vasoconstriction in different vascular beds and species. Furthermore, 15-F2t-IsoP induces smooth muscle cells mitogenesis and monocyte adhesion to endothelial cells. In clinical studies, 15-F2t-IsoP levels are increased in vascular disorders involving atherosclerosis, ischemia-reperfusion and inflammation.

FUTURE PROSPECTS AND PROJECTS

Whether the effects observed in vitro are observed consistently in vivo at physiological concentrations and whether these effects contribute to pathological states in vivo is still debated.

Oxidative stress and baroreflex sensitivity in healthy subjects and patients with mild-to-moderate hypertension

Decreased baroreflex sensitivity (BRS) is a prognostic marker in essential hypertension. Animal experiments suggest that decreased BRS is related to increased oxidative stress. Our study was aimed at testing whether oxidative stress, estimated by isoprostane 15-F(2t)-IsoP urinary levels, is correlated to BRS variation in healthy subjects as well as in patients suffering from essential hypertension. Urinary 15-F(2t)-IsoP levels and BRS were evaluated in two groups of subjects: healthy volunteers (n=64) and patients with untreated mild-to-moderate hypertension (n=33). Data were analysed in 61 and 31 subjects, respectively, BRS analysis being impossible in three and two subjects, respectively. 15-F(2t)-IsoP levels were measured using gas chromatography/mass spectrometry. BRS was measured using the sequence method [PS+/RR+ and PS-/RR-] and crossspectral analysis (CSP) (MF gain) at rest, lying down. No significant correlation was found between basal urinary 15-F(2t)-IsoP levels and BRS (sequence method and CSP) in either healthy controls or hypertensive patients. Our study shows that oxidative stress is not involved in interindividual variations of BRS in healthy subjects and patients suffering from mild-to-moderate hypertensionJournal of Human Hypertension (2004) 18, 517-521. doi:10.1038/sj.jhh.1001684 Published online 12 February 2004

[Pulmonary embolism with right intra-auricular thrombus. Fatal outcome during fibrinolysis]

INTRODUCTION

The spontaneous prognosis of pulmonary embolism associated with mobile intra-cardiac thrombus is most severe, and the choice of a therapeutic strategy is often difficult.

OBSERVATION

The treatment of a patient with intravenous fibrinolytics for massive pulmonary embolism and right atrium thrombus was complicated by his early death. We attributed his death to the migration of the intra-cardiac thrombus. Indeed, the cardiac ultrasound, performed when the patient's hemodynamic state had worsened, revealed the complete disappearance of the thrombus too early to correspond to its complete lysis (30th minute of fibrinolysis).

COMMENTS

In this pathology, several therapeutic approaches are possible. Surgical removal of the embolus has been validated, but cannot be proposed to all patients since it is a high-risk intervention. Fibrinolysis is generally efficient but exposes the patient to the risk of migration of the intra-cavity thrombus with occasionally deleterious evolution (as in our patient). Heparin treatment alone has been proposed as an alternative when the other two techniques are contraindicated. These techniques currently require assessment in a randomized study, in order to define the appropriate therapeutic strategy.

[Does the time between preoperative interruption of aspirin intake and operation influence postoperative blood loss and transfusion requirement in coronary artery bypass graft?]

OBJECTIVE

Impact of the interval between interruption of aspirin intake and surgery on postoperative bleeding and transfusion in coronary artery bypass graft (CABG), with extracorporeal circulation (ECC).

STUDY DESIGN

Retrospective study.

PATIENTS AND METHODS

Four hundred and twelve patients having undergone CABG were retrospectively reviewed. Three groups were evaluated according to the length of the interval defined above: Group I (< 3 days), Group II (3-7 days), Group III (> 7 days or without aspirin intake). Postoperative blood loss at 3rd, 6th, 12th, and 24th hour and transfusion requirements were assessed for the 3 groups. Aprotinin (low dose, 2 M KIU) was systematically included in the priming of the ECC circuit.

RESULTS

There were no significant differences among groups for weight, size, duration of ECC, and number of bypasses. No significant correlation was noted among the 3 groups for postoperative blood loss and transfusion. Multivariate analysis showed that factors associated to a higher risk of excessive bleeding were ECC duration and number of arterial grafts. Factors associated with a higher risk of transfusion were: emergency, minimum patient temperature during ECC, weight and preoperative haemoglobin level. Aspirine intake was not associated with an increase of bleeding or transfusion.

CONCLUSION

Our study showed that in our practice using systematic low dose of aprotinin when priming the ECC circuit, aspirin did not significantly increase bleeding or transfusion requirements in CABG with ECC, whatever the interval between interruption of aspirin intake and surgery. Consequently, in our practice, aspirin intake is interrupted on hospitalisation, one day before surgery.

[Leukotrienes and 12-HETE: key mediators of angiotensin II-mediated vascular effects.Rol in hypertension]

Arachidonic acid metabolism-derived products are key mediators of angiotensin II-mediated vascular effects. The modulatory effect of cyclooxygenase derived products--in particular thromboxane A2 and prostaglandin H2--in angiotensin II-mediated vascular effects is well established. In contrast, few studies have assessed the involvement of lipoxygenase-derived products in the vascular effects of angiotensin II. Cysteinyl leukotrienes (5-lipoxygenase-derived products) and 12-hydroxyeicosatetraenoic acids (12-HETE) (12-lipoxygenase-derived products) are potent proinflammatory and vasomotor mediators. Their biosynthesis is increased in various models of hypertension. In addition, compelling evidence has suggested that they might contribute to the vasoconstrictor, hypertrophic and mitogenic effects of angiotensin II. The demonstration of their contribution to angiotensin II-mediated vascular effects may explain, at least in part, the vascular inflammatory complications associated with hypertension.

Syntheses and preliminary pharmacological evaluation of the two epimers of the 5-F2t-isoprostane

The total synthesis of the 5-F2t-isoprostane 1 and its 5-epimer 2 from diacetone-D-glucose is described. We report preliminary data on the vascular properties of these compounds.

Increased lipid peroxidation in patients with pulmonary hypertension

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 isoprostaglandin F(2alpha) type III (iPF(2alpha)-III), an F(2)-isoprostane, in patients with pulmonary hypertension (PHT) in comparison with healthy controls. The secondary objective was to test whether baseline iPF(2alpha)-III levels correlate to the reversibility of pulmonary hypertension in response to inhaled NO challenge. Urinary iPF(2alpha)-III levels were measured by gas chromatography-mass spectrometry in 25 patients with PHT, 14 of whom were investigated for response to inhaled NO challenge. Urinary iPF(2alpha)-III levels in PHT patients (225 +/- 27 pmol/mmol creatinine) were 2.3 times as high as in controls (97 +/- 7 pmol/mmol creatinine, p < 0.001). The mean pulmonary arterial pressure variation and the pulmonary vascular resistance variation in response to inhaled NO were correlated to basal iPF(2alpha)-III levels. This study shows that oxidative stress is increased in patients with pulmonary hypertension. Furthermore, iPF(2alpha)-III levels inversely correlate to pulmonary vasoreactivity. These observations are consistent with the hypothesis that free radical generation is involved in PHT pathogenesis.

Formation of isoprostanes in children with type IIa hypercholesterolemia

F2-isoprostanes are stable lipid peroxidation products of arachidonic acid and their quantification provides a novel approach to the assessment of oxidative stress in vivo. F2-isoprostanes are present in increased amounts in adult hypercholesterolemia, but no data exist concerning children. We investigated urinary isoprostaglandin F2, type III production as an index of lipid peroxidation in 15 children presenting with type IIa hypercholesterolemia (serum total cholesterol, 290 [SD +/- 70] mg/dl; low-density lipoprotein cholesterol, 210 [SD +/- 90] mg/dl) compared with 15 sex- and age-paired control children (serum total cholesterol, 160 [SD +/- 20] mg/dl). Urinary levels of isoprostaglandin F2alpha type III were measured by gas chromatography mass spectrometry. Urinary concentrations did not differ significantly in hypercholesterolemic children compared with control children (84.7 [SD +/- 37] vs. 96 [SD +/- 35] pmol/mmol creatinine, respectively). No significant correlation was found with total cholesterol, low-density-lipoprotein and high-density-lipoprotein cholesterol, and apolipoprotein B and A1 serum levels. F2-isoprostane urinary levels in children with type IIa hypercholesterolemia do not differ from those of age- and sex-matched control children and are not correlated to blood lipid parameters, suggesting that hypercholesterolemia is not associated with increased lipid peroxidation in childhood.

Enhanced in vivo lipid peroxidation in scleroderma spectrum disorders

OBJECTIVE

A new family of prostaglandin F2 isomers called F2-isoprostanes, produced by free radical peroxidation of arachidonic acid, has recently been described in vivo. Its quantification has been suggested to be a reliable measure of oxidant injury in vivo. The purpose of this study was to investigate urinary F2-isoprostane formation as an index of lipid peroxidation in scleroderma spectrum disorders.

METHODS

Urine samples were obtained from 52 patients with systemic sclerosis (SSc; n = 37) or undifferentiated connective tissue diseases (UCTD; n = 15) and from 20 healthy volunteers. Urinary isoprostaglandin F2alpha type III (iPF2alpha-III) and 11-dehydro thromboxane B2 (11-dehydroTXB2) concentrations were determined using enzyme immunoassays.

RESULTS

The urinary concentration of iPF2alpha-III was approximately twice as high in patients (mean +/- SEM 229+/-16 pmoles/mmoles creatinine) as in controls (116+/-9 pmoles/mmoles creatinine) (P < 0.0001). However, the urinary concentration of iPF2alpha-III was not significantly different among patients with UCTD, limited SSc, and diffuse SSc (mean +/- SEM 221+/-27 versus 245+/-32 versus 220+/-25 pmoles/mmoles creatinine, respectively). No significant correlation was found between the urinary concentrations of iPF2alpha-III and 11-dehydroTXB2.

CONCLUSION

This study provides evidence of enhanced lipid peroxidation in both SSc and UCTD, and suggests a rationale for antioxidant treatment of SSc. Formation of F2-isoprostanes has to be investigated as a means for the evaluation of such therapy.

Determination of isoprostaglandin F2alpha type III in human urine by gas chromatography-electronic impact mass spectrometry. Comparison with enzyme immunoassay

F2-Isoprostanes are stable lipid peroxidation products of arachidonic acid, the quantification of which provides an index of oxidative stress in vivo. We describe a method for analysing isoprostaglandin F2alpha type III (15-F2t-IsoP) in biological fluids. The method involves solid-phase extraction on octadecyl endcapped and aminopropyl cartridges. After conversion to trimethylsilyl ester trimethylsilyl ether derivatives, isoprostaglandin F2alpha type III is analysed by mass spectrometry, operated in electronic impact selected ion monitoring mode. We have compared enzyme immunoassay (EIA; Cayman, Ann Arbor, MI, USA) to this method with 30 human urine aliquots following the same extraction procedure in order to determine the agreement between both methods. Isoprostaglandin F2alpha type III concentrations determined with gas chromatography-mass spectrometry (GC-MS) did not agree with those determined with EIA. Our results suggest that GC-MS and EIA do not measure the same compounds. As a consequence, comparison of clinical results using GC-MS and EIA should be avoided.

Using a WWW-based module for problem-based learning in a cardiovascular pharmacology course

The authors have constructed a problem-based learning (PBL) computer program that makes full use of Internet facilities, and is aimed at providing a stimulating supplement to standard teaching practices. The authors report on students' reactions to this new method of teaching.

Isoprostaglandin E2 type-III (8-iso-prostaglandin E2) evoked contractions in the human internal mammary artery

E2-isoprostanes are recently discovered compounds that are produced in vivo from free radical-catalysed peroxidation of arachidonic acid. One such compound whose formation is favoured by this mechanism is isoprostaglandin E2 type III (iPE2-III, also named 8-iso-prostaglandin E2 or 15-E2t-isoprostaglandin). The aim of this study was to evaluate the vasomotor properties of iPE2-III in isolated human internal mammary artery. In organ bath, iPE2-III was approximately 10 times more potent than isoprostaglandin F2alpha-III and 27 times more potent than prostaglandin E2, whereas both isoprostaglandin F3alpha-III and 15-epi-isoprostaglandin F2alpha-II induced weak contractions. The responses to iPE2-III were inhibited in a concentration-dependent manner by the thromboxane A2 receptor antagonist GR 32191 (3.10(-9) to 3.10(-7) M). Indomethacin, a cyclooxygenase inhibitor and phosphoramidon, an endothelin converting enzyme inhibitor, did not affect iPE2-III response. These data shows that iPE2-III is a more potent vasoconstrictor of human internal mammary arteries than isoprostaglandin F2alpha-III. These effects are mediated by TP receptors, but involve neither cyclooxygenase products nor endothelins. iPE2-III production may induce more pronounced vasomotor effects than isoprostaglandin F2alpha-III in situations of oxidative stress, and in particular may modulate internal mammary artery tone following coronary bypass surgery.

Vascular biology of the isoprostanes

Isoprostanes are a family of compounds produced from polyunsaturated fatty acids via a free-radical-catalysed mechanism. F(2)-isoprostanes are prostaglandin F(2alpha) isomers derived from arachidonic acid. These compounds induce potent vasoconstriction, mediated primarily by TP receptor stimulation, and in some vessels by the release of cyclooxygenase products. This vasoconstriction may be modulated by the endothelium through the release of NO. Potent vasoconstriction is also observed with E(2)-isoprostanes. Experimental and clinical data suggest a role for F(2)-isoprostanes in atherogenesis. These compounds can be detected in free forms in biological fluids as well as esterified in low-density lipoproteins or cell membranes. Their quantification represents a reliable marker of lipid peroxidation. Elevated levels of F(2)-isoprostanes in biological fluids in pathological conditions including atherosclerosis, ischaemia-reperfusion injury, and inflammatory vascular diseases, suggest a relationship between lipid peroxidation and such diseases. F(2)-isoprostanes are currently being investigated as non-invasive quantitative markers to monitor the response to anti-oxidant treatment.

Urinary F2-isoprostanes formation in kidney transplantation

BACKGROUND

Oxygen free-radical mediated lipid peroxidation has been implicated in many diseases such as chronic renal failure, hemodialysis and chronic kidney transplant rejection. However, insight into the role of free radical generation in kidney transplantation has been constrained by the limitations of current indexes of oxidant stress in vivo. Isoprostaglandin F2alpha type-III (iPF2alpha-III, formerly known as 8-iso-prostaglandin F2alpha) is emerging as a reliable marker of oxidant stress in vivo. The purpose of our study was to investigate iPF2alpha-III formation as an index of lipid peroxidation in the 5 d following kidney transplantation.

METHODS

Urinary iPF2alpha-III measurements were performed by enzyme immunoassay from day I to 5 in 11 patients undergoing kidney transplantation. Results were compared with 11 healthy volunteers matched in sex, age and cigarette smoking.

RESULTS

Urinary excretion of iPF2alpha-III at day 1 did not significantly differ between control and transplant group (111 +/- 17 vs. 92 +/- 10 pM/ mM creatinine, respectively, NS). Urinary iPF2alpha-III levels did not differ between day 1 to 5, and were not correlated to cold ischaemia time.

CONCLUSION

Our study shows no evidence of enhanced lipid peroxidation in the first 5 d following kidney transplantation.

Cysteinyl leukotrienes are involved in angiotensin II-induced contraction of aorta from spontaneously hypertensive rats

OBJECTIVE

Non specific lipoxygenase inhibitors have been reported to reduce the in vitro constrictor response and the in vivo pressor effect of angiotensin II in rats. The aim of this study was to assess the role of cysteinyl leukotrienes, in the vascular response to angiotensin II in spontaneously hypertensive rats (SHR).

METHODS

Rings of thoracic aorta from SHR and normotensive Wistar-Kyoto rats (WKY) were compared in terms of contractile responses and release of cysteinyl leukotrienes in response to angiotensin II.

RESULTS

Pretreatment with the specific 5-lipoxygenase inhibitor AA861 10 microM reduced the efficacy of angiotensin II in intact and endothelium-denuded aorta from SHR (% inhibition vs. control: 65+/-12.6% with endothelium (n=6), P<0.05; 43+/-7.2% without endothelium (n=6), P<0.05) but not in aorta from WKY. In addition, in aorta from SHR, the CysLT(1) receptor antagonist MK571 1 microM reduced by 55+/-6.1% (n=6, P<0.05) the contractile effects of angiotensin II in rings with endothelium but not in endothelium-denuded rings. Angiotensin II induced a 8.6+/-2.1-fold increase in cysteinyl leukotriene production in aorta rings from SHR with endothelium which was prevented by the AT(1) receptor antagonist losartan 1 microM but not by the AT(2) receptor antagonist PD123319 0.1 microM. In aorta rings from WKY, cysteinyl leukotriene production remained unchanged after exposition to angiotensin II. The cysteinyl leukotrienes (up to 0.1 microM) induced contractions in aorta rings from SHR but not from WKY.

CONCLUSIONS

These data suggest that cysteinyl leukotrienes, acting at least in part on endothelial CysLT(1) receptors, are involved in the contractile response to angiotensin II in isolated aorta from SHR but not from WKY.

Angiotensin II-induced contractions in human internal mammary artery: effects of cyclooxygenase and lipoxygenase inhibition

OBJECTIVE

This study investigated, in isolated human internal mammary artery, the involvement of the cyclooxygenase and the lipoxygenase pathways of arachidonic acid metabolism in the contraction induced by angiotensin II.

METHODS

Rings of human internal mammary arteries were suspended in organ baths for recording of isometric tension. In addition, the release of eicosanoids in response to angiotensin II (0.3 microM) was measured by enzyme immunoassay.

RESULTS

In human arterial rings without endothelial dependent relaxation in response to substance P or acetylcholine, the angiotensin II-induced contractions were significantly (P<0.05) reduced by 27% in the presence of GR32191 0.3 microM (thromboxane A(2) (TXA(2)) receptor antagonist) but remained unchanged in the presence of dazoxiben 100 microM (thromboxane synthase inhibitor). In addition, angiotensin II failed to modify TXB(2) and 6-keto-PGF(1alpha) production. These results suggest the contribution of a TXA(2)/PGH(2) agonist other than TXA(2) in angiotensin II-induced contractions. However, indomethacin increased (P<0.05) angiotensin II-mediated contractile response and cysteinyl leukotriene production, suggesting a redirection of arachidonic acid metabolism from the cyclooxygenase pathway to the lipoxygenase pathway. Indeed, the contractions induced by angiotensin II were inhibited (P<0.05) by phenidone 100 microM (cyclooxygenase and lipoxygenase inhibitor), baicalein 100 microM (5-, 12- and 15-lipoxygenases inhibitor), AA861 10 microM (5-lipoxygenase inhibitor) and MK571 1 microM (CysLT(1) receptor antagonist). Cysteinyl leukotrienes were released in response to angiotensin II (pg/mg dry weight tissue: 32+/-9 (basal, n=6) vs. 49+/-9 (angiotensin II 0.3 microM, n=6), P<0.05). LTD(4), and at a lesser degree LTC(4), induced contractions of internal mammary artery and MK571 1 microM abolished the contraction to LTD(4).

CONCLUSIONS

This study suggests that the in vitro vasoconstrictor effects of angiotensin II in human internal mammary artery are enhanced at least in part by eicosanoids produced by the cyclooxygenase pathway, probably PGH(2), acting on TXA(2)/PGH(2) receptors, and by lipoxygenase-derived products, particularly cysteinyl leukotrienes acting on CysLT(1) receptors.

Human internal mammary artery contraction by isoprostaglandin f(2alpha) type-III [8-iso-prostaglandin F(2alpha)]

Isoprostaglandin F(2alpha) type-III (formerly known as 8-iso-prostaglandin F(2alpha)) is produced in large quantities in vivo in clinical situations associated with oxidant stress such as atherosclerosis, hypercholesterolemia, and myocardial reperfusion. Isoprostaglandin F(2alpha) type-III may alter smooth muscle and platelet functions. The aim of this study was to evaluate the effects of isoprostaglandin F(2alpha) type-III on isolated human internal mammary arteries, and to characterise the signalling underlying mechanisms. In organ baths, concentration-dependent contractions of human internal mammary arteries were obtained in response to isoprostaglandin F(2alpha) type-III stimulation. The responses to isoprostaglandin F(2alpha) type-III were inhibited in a concentration-dependent manner by the thromboxane A(2) receptor antagonist, GR 32191 ([1R-[1 alpha(Z), 2beta,3beta,5 alpha(+)-7-[[1, 1'-biphenyl)-4-yl]methoxy]-3-hydroxy-2-(1-piperidinyl) cyclo pentyl]-4-4heptanoic acid], hydrochloride), 3x10(-9) to 3x10(-7) M). However, this effect was associated with a decreased maximal contraction. AH 6809 (6-isopropoxy-9-oxoxanthene-2-carboxylic acid, 10(-6) to 3x10(-5) M), an EP(1)-DP receptor antagonist had no effect on isoprostaglandin F(2alpha) type-III-induced contractions. The maximal responses to isoprostaglandin F(2alpha) type-III were significantly reduced in the presence of the cyclooxygenase inhibitor indomethacin (10(-5) M) (E(max): 147+/-20% vs. 213+/-19% in control group, P<0.05). Isoprostaglandin F(2alpha) type-III stimulated thromboxane B(2) release (5.7-fold increase) from human internal mammary arteries. Baicaleine, a non-specific lipoxygenase inhibitor, (10(-4) M) and AA 861 (2,3,5-trimethyl-6-(12-hydroxy-5, 10-dodecadiynyl)-1,4 benzoquinone), a 5-lipoxygenase inhibitor (10(-5) M) did not affect isoprostaglandin F(2alpha) type-III response. In conclusion, this study shows that (1) isoprostaglandin F(2alpha) type-III is a vasoconstrictor in human internal mammary arteries, with a potency equivalent to prostaglandin F(2alpha), (2) the contractions induced by isoprostaglandin F(2alpha) type-III are mediated by TP receptor but not EP(1)-DP-receptor activation, (3) thromboxane A(2) but not cysteinyl leukotrienes production is involved in the vascular effects of isoprostaglandin F(2alpha) type-III. Isoprostaglandin F(2alpha) type-III, produced at sites of free radical generation, may play an important role in internal mammary artery spasm in situations of oxidant stress such as coronary bypass surgery.

Vasoconstrictor effects of iso-prostaglandin F2alpha type-III (8-iso-prostaglandin F2alpha) on human saphenous veins

Free radical generation can initiate the peroxidation of arachidonic acid, resulting in a non-cyclooxygenase-dependent production of bioactive prostaglandin F2-like compounds. We have investigated the effects of iso-prostaglandin F2alpha type III, (iPF2alpha-III, formerly named 8-iso prostaglandin F2alpha) on human saphenous veins, and characterized the underlying mechanisms. In organ baths, the contractile effects of iPF2alpha-III were tested on saphenous vein rings coming from 22 patients. iPF2alpha-III induced concentration-dependent contractions of isolated human saphenous veins. The maximal contraction did not differ significantly from that of prostaglandin F2alpha (PGF2alpha). The pD2 values for iPF2alpha-III, PGF2alpha, endothelin-1 (ET-1), and U46619 (a stable thromboxane A2 mimetic) were 6.31+/-0.12, 5.66+/-0.13, 7.37+/-0.08, and 7.99+/-0.31, respectively (p < 0.001 for U46619 vs. iPF2alpha-III and PGF2alpha; and ET-1 vs. PGF2alpha). Emax values of iPF2alpha-III, PGF2alpha, ET-1, and U46619 were 137.7+/-24.3%, 145.9+/-7.5%, 92.9+/-16.8%, and 238.7+/-23.7%, respectively (p < 0.001 for U46619 vs. iPF2alpha-III, PGF2alpha and ET-1; and for PGF2alpha vs. ET-1). The responses to iPF2alpha-III were inhibited by GR 32191 10(-7) M, a TP-receptor antagonist, without affecting the maximal response (pD2 values were 5.98+/-0.06 in the absence, and 5.22+/-0.05 in the presence of GR32191; p < 0.001). Concentration-effect curves to iPF2alpha-III were not affected by phosphoramidon 10(-5) M (an endothelin converting enzyme inhibitor), BQ123 10(-6) M (a selective ET(A)-receptor antagonist), BQ788 10(-6) M (a selective ET(B)-receptor antagonist), and indomethacin 10(-5) M (a cyclooxygenase inhibitor). Finally, the contractile response of iPF2alpha-III did not involve the release of thromboxane B2 and ET-1, measured using enzyme immunoassays. This study demonstrates that iPF2alpha-III is a vasoconstrictor of human saphenous veins, with a potency fourfold greater than that of PGF2alpha, and 50 times less than that of the thromboxane A2 mimetic, U46619. These effects are mediated at least in part by TP-receptor stimulation, but do not involve thromboxane A2 or ET-1 release.

Furosemide inhibits thromboxane A2-induced contraction in isolated human internal mammary artery and saphenous vein

Evidence suggests that, in addition to its diuretic property, furosemide also may exert direct vascular effects. Because thromboxane A2 (TXA2) has a role in the control of vascular tone, we investigated the effect of furosemide on the contraction induced by U46619 (a stable TXA2 mimetic) on isolated human internal mammary artery (IMA) and saphenous vein (SV). Concentration-response curves to U46619 were performed in the absence (vehicle) or the presence of furosemide (0.1-1 mM) on rings of IMA and SV. In addition, the relaxant effect of furosemide (0.1 microM-1 mM) also was evaluated on U46619-precontracted IMA and SV. The participation of cyclooxygenase derivatives was studied by pretreatment with indomethacin. Furosemide (0.1-1.0 mM) caused parallel rightward shifts of U46619 concentration-response curves without affecting the maximal responses in both IMA and SV. Treatment with indomethacin (1 microM) modified neither the inhibitory effect of furosemide on U46619-induced contractions, nor the relaxant effect of furosemide on U46619-induced contractions, nor the relaxant effect of furosemide on U46619-precontracted IMA and SV. In conclusion, furosemide at high concentrations inhibited U46619-induced contraction in human isolated IMA and SV and relaxed U46619-precontracted IMA and SV by mechanisms independent of the release of relaxant prostaglandins. These results suggest that blockade of TXA2 receptors by furosemide may contribute to explaining the therapeutic effects of furosemide in the treatment of severe heart failure.