Inflammation versus mechanical stretch biomarkers over time in acutely decompensated heart failure with reduced ejection fraction.

Heart failure can be associated with inflammation but it is unclear if inflammation is directly related to hemodynamic worsening or is an independent pathway. Our aim was to investigate inflammation and mechanical stress using serial measurements of biomarkers in acute and chronic heart failure with reduced ejection fraction (AHF and CHF). METHOD: The following biomarkers were measured on admission, at discharge and one month after discharge: B-type natriuretic peptide (BNP), high-sensitivity C-Reactive protein (hsCRP), Tumour Necrosis Factor alpha (TNFα), interleukin 6 (IL6), myeloperoxidase (MPO), suppression of tumorigenicity 2 (ST2), mid-regional pro-adrenomedullin (MR-proADM), galectin 3 (Gal3), Growth differentiating factor 15 (GDF15) and procalcitonin (PCT). RESULTS: In control CHF group (n=20, 69±11y, NYHA 1-2), most biomarker levels were low and stable over time. In AHF (n=55, 71±14y), BNP, ST2 and GDF15 levels were highly increased on admission and then decreased rapidly with clinical improvement; BNP, ST2 and GDF15 levels were statistically correlated (r=0.64, 0.46 and 0.39; p<0.001 for both). Both hsCRP, MPO, TNFα and Gal3 levels were increased in most AHF patients (70, 56, 83 and 98% respectively) with poor change over time. HsCRP, MPO and TNFα levels were correlated. IL6, MR-proADM and PCT levels were slightly increased, without change over time. Highest quartiles of BNP and ST2 were associated with death or readmission at one year (HR 2.33 [95CI 1.13-4.80] and 2.42 [1.27-4.60]). CONCLUSION: AHF is associated with systemic inflammation. This inflammatory response continued up to one month after discharge despite normalisation of mechanical stress-related markers.

Decreased tryptophan and increased kynurenine levels in mastocytosis associated with digestive symptoms.

The main metabolism pathway of tryptophan is protein formation, but it can also be metabolized into serotonin and kynurenine. Indoleamine 2,3-dioxygenase (IDO) is the enzyme that catalyzes the degradation of tryptophan into kynurenine. Mastocytosis is a heterogeneous disease characterized by mast cell accumulation in various tissues with 57% of patients having gastrointestinal involvement. We studied tryptophan metabolism in mastocytosis patients displaying or not gastrointestinal features and healthy subjects (n = 26 in each group). Mastocytosis patients with digestive symptoms displayed significantly increased kynurenine level and IDO activity as compared to healthy controls and mastocytosis patients without digestive symptoms. This could be linked to mast cell-mediated digestive inflammation among patients with mastocytosis. This work is the first focusing on kynurenine pathway in a mast cell disease and could help to understand the pathogenesis of digestive features in mastocytosis as well as in other mast cell-mediated diseases.

Mast cells' involvement in inflammation pathways linked to depression: evidence in mastocytosis.

Converging sources of evidence point to a role for inflammation in the development of depression, fatigue and cognitive dysfunction. More precisely, the tryptophan (TRP) catabolism is thought to play a major role in inflammation-induced depression. Mastocytosis is a rare disease in which chronic symptoms, including depression, are related to mast cell accumulation and activation. Our objectives were to study the correlations between neuropsychiatric features and the TRP catabolism pathway in mastocytosis in order to demonstrate mast cells' potential involvement in inflammation-induced depression. Fifty-four patients with mastocytosis and a mean age of 50.1 years were enrolled in the study and compared healthy age-matched controls. Depression and stress were evaluated with the Beck Depression Inventory revised and the Perceived Stress Scale. All patients had measurements of TRP, serotonin (5-HT), kynurenine (KYN), indoleamine 2,3-dioxygenase 1 (IDO1) activity (ratio KYN/TRP), kynurenic acid (KA) and quinolinic acid (QA). Patients displayed significantly lower levels of TRP and 5-HT without hypoalbuminemia or malabsorption, higher IDO1 activity, and higher levels of KA and QA, with an imbalance towards the latter. High perceived stress and high depression scores were associated with low TRP and high IDO1 activity. In conclusion, TRP metabolism is altered in mastocytosis and correlates with perceived stress and depression, demonstrating mast cells' involvement in inflammation pathways linked to depression.

Pathogenic prions deviate PrP(C) signaling in neuronal cells and impair A-beta clearance.

The subversion of the normal function exerted by the cellular prion protein (PrP(C)) in neurons by pathogenic prions is assumed to have a central role in the pathogenesis of transmissible spongiform encephalopathies. Using two murine models of prion infection, the 1C11 neuronal cell line and neurospheres, we document that prion infection is associated with the constitutive activation of signaling targets normally coupled with PrP(C), including the Fyn kinase, the mitogen-associated protein kinases ERK1/2 and the CREB transcription factor. PrP(C)-dependent signaling overactivation in infected cells is associated with the recruitment of p38 and JNK stress-associated kinases. Downstream from CREB, prion-infected cells exhibit reduced activity of the matrix metalloprotease (MMP)-9. As MMP-9 catalyzes the degradation of the amyloid A-beta peptide, the decrease in MMP-9 activity in prion-infected cells causes a significant impairment of the clearance of A-beta, leading to its accumulation. By exploiting two 1C11-infected clones accumulating high or moderate levels of prions, we show that the prion-induced changes are correlated with the level of infectivity. Of note, a dose-dependent increase in A-beta levels was also found in the cerebrospinal fluid of mice inoculated with these infected clones. By demonstrating that pathogenic prions trigger increases in A-beta levels through the deviation of PrP(C) signaling, our data argue that A-beta may exacerbate prion-induced toxicity.

Systemic mastocytosis and bone involvement in a cohort of 75 patients.

OBJECTIVES: To investigate bone involvement in a large cohort of systemic mastocytosis (SM) patients, and evaluate the efficacy of bisphosphonate therapy. PATIENTS AND METHODS: From 2000 to 2004, 75 patients with SM according to WHO criteria underwent skeletal x-rays and bone mineral density (BMD) assessment. Sequential BMD assessments were performed in nine patients treated with bisphosphonate (mean follow-up 65 months). RESULTS: 37 patients (49%) had bone involvement according to both x-rays and BMD evaluations: osteoporosis (23 patients, 31%, mean lumbar spine T score: -3 SD), with vertebral fracture (13 patients, 17%), axial skeleton osteosclerosis (six patients, 8%), mixed patterns (three patients), osteopenia with pre-existing fractures (four patients) and focal osteolytic lesion (one patient). Blood count abnormalities were associated with osteosclerosis (p=0.005). In nine patients with osteoporosis and bisphosphonate therapy, mean lumbar spine BMD increased from 0.83 to 0.92 g/cm(2) (+11.1%; ie, +2.05% per year) without recurrence of vertebral fracture. CONCLUSION: Half of adult patients with SM have bone involvement. Osteoporosis is the most prevalent bone manifestation in SM (31%). Bisphosphonate therapy seems efficient to improve lumbar spine BMD during SM-related osteoporosis. Spine x-ray and BMD should be performed in all SM patients to detect those who may benefit from anti-osteoporotic therapy.

Modulation of bleomycin-induced lung fibrosis by serotonin receptor antagonists in mice.

Serotonin (5-hydroxytryptamine; 5-HT) is known to increase proliferation and collagen synthesis by fibroblasts. Two receptor subtypes, 5-HT2A and 5-HT2B, have been shown to play the most important roles in the lung. In the present study, the role of serotonin in lung fibrosis was investigated using the bleomycin mouse model. Serotonin concentrations in lung homogenates increased significantly over the time course of bleomycin-induced fibrosis, with a maximum at day seven. The expression of serotonin receptors 5-HT2A and 5-HT2B increased in the lung after bleomycin treatment, as assessed by PCR, specific binding and immunohistochemistry. Blockage of 5-HT2A receptors by ketanserin and 5-HT2B receptors by SB215505 reduced bleomycin-induced lung fibrosis, as demonstrated by reduced lung collagen content and reduced procollagen 1 and procollagen 3 mRNA expression. Serotonin antagonists promoted an antifibrotic environment by decreasing the lung mRNA levels of transforming growth factor-beta1, connective growth factor and plasminogen activator inhibitor-1 mRNA, but had minimal effects on lung inflammation as assessed by bronchoalveolar lavage cytology analysis. Interestingly, the 5-HT2B receptor was strongly expressed by fibroblasts in the fibroblastic foci in human idiopathic pulmonary fibrosis samples. In conclusion, the present study showed involvement of serotonin in the pathophysiology of bleomycin-induced lung fibrosis in mice and identified it as a potential therapeutic target in lung fibrotic disorders.

A novel mutation (G114V) in the prion protein gene in a family with inherited prion disease.

Inherited prion diseases are characterized by mutations in the PRNP gene encoding the prion protein (PrP). We report a novel missense mutation in the PRNP gene (resulting in a G114V mutation in PrP) in members of a Uruguayan family with clinical and histopathologic features of prion disease. Affected individuals were characterized by an early age at onset, initial neuropsychiatric symptoms, late dementia with prominent pyramidal and extrapyramidal symptoms, and long disease duration.

[Point care testing in blood gas and electrolyte analysis : examples of implementation and cost analysis]. / Gazométrie et électrolytes sanguins délocalisés: exemples d'organisation et évaluation économique.

An increasing proportion of laboratories manage and organize point of care testing (POCT). The purpose of this article is to describe the implementation made at Lariboisière hospital for three remote blood gas analysers. The most important aspect in this achievement is the comprehensive computerization, making possible real time management of POCT in agreement with the Point of Care unit Management team. In addition, we present a running cost analysis, comparing three Blood gas systems (Rapidlab860, Rapidpoint 400--Bayer Diagnostics and i-Stat Abbott Diagnostics). This study indicates that cost per test hugely varies based on the daily sample demand. In addition to analytical and organizational items, the clinical chemist should consider the testing demand as a key factor in choosing an analyser for POCT.

Histological, immunohistochemical, ultrastructural and biochemical study of human gastric composite tumor: expression of the serotonin-2B receptor by the neuroendocrine component.

We report a case of a human gastric composite tumor occurring seven years after a partial gastrectomy for a low grade B cell MALT lymphoma. Histological examination of the tumor revealed two intimately intermingled components: 1. A moderately to poorly differentiated tubulo-acinar adenocarcinoma with signet-ring cells; and 2. Isolated or clustered small neuroendocrine cells without atypia expressing chromogranin A, somatostatin and/or glucagon, serotonin (5-HT) and, the 5-HT2B receptors. In addition to immunohistochemical detection, the presence of 5-HT2B receptors was shown pharmacologically through [125I]-DOI binding. Since 5-HT2B receptors have been demonstrated to have autocrine functions and, mitogenic and transforming properties, these results suggest a role of 5-HT in neuroendocrine malignant transformation. On the other hand, the expression of somatostatin and the detection by reverse transcriptase polymerase chain reaction (RT-PCR) of somatostatin receptor subtypes 2, 3, and 5, which have been shown to be involved in tumor regression, might account for the long evolution of this case (> 5 yr). This case illustrates the importance of local humoral modulation in tumor growth. Moreover, ultrastructural results favor a unique origin of the tumor cells from one amphicrine cell type.

Platelet monoamine oxidase B activity is inversely associated with plasma cotinine concentration.

Cigarette smoke but not nicotine inhibits irreversibly platelet monoamine oxidase B (MAO-B) activity. Current smokers have decreased platelet MAO-B activity which normalizes when smokers quit. Normalization of platelet MAO-B activity probably depends on platelet turnover. Platelet MAO-B activity has been found to be correlated with plasma thiocyanate concentration. The aim of this study was to investigate in smokers whether platelet MAO-B activity is related to plasma cotinine concentration, an indirect index of use of smoked tobacco. We determined simultaneously plasma cotinine concentration and platelet MAO-B activity in 85 cigarette smokers [mean (+/- SD) age 39 +/- 8.8 years, 55 men]. Platelet MAO-B activity was lower in male than in female smokers (14.1 +/- 7.9 versus 17.8 +/- 7.2 nmol/h/10(9) platelets, p = 0.03). Platelet MAO-B activity correlated positively with age (r = 0.26, p = 0.01) and inversely with plasma cotinine concentration (r = -0.32, p = 0.002) but not with number of cigarettes smoked or with Fagerström Tolerance Questionnaire score. Multiple linear regression analysis showed that 49% of the age-adjusted variance in platelet MAO-B activity (R2 = 0.489, p < 0.0001) was explained by plasma cotinine concentration (p < 0.001) and gender (p = 0.037). It was concluded that platelet MAO-B activity in smokers is inversely associated with plasma cotinine level, an index of smoked tobacco use. Further studies are needed to investigate whether measurement of platelet MAO-B activity can be used as a long-term index of tobacco use and smoke exposure.

High plasma serotonin levels in primary pulmonary hypertension. Effect of long-term epoprostenol (prostacyclin) therapy.

Elevated plasma serotonin is associated with primary pulmonary hypertension (PPH). To test whether this elevation could be related to platelet activation, the 2 pools of blood serotonin (platelets and plasma) and plasma 5-hydroxyindoleacetic acid (5-HIAA) as well as markers of platelet activation (alpha(IIb)beta(3), CD36, P-selectin, and CD63 membrane epitopes) were measured in 16 patients with severe PPH (group 1) before and at days 10 and 40 of treatment with a continuous infusion of epoprostenol (prostacyclin). The same biological parameters were also measured in 19 healthy subjects (group 2) and in 10 patients after cardiovascular surgery with extracorporeal circulation (group 3), a condition known to profoundly activate the platelets. Twelve PPH patients showed hemodynamic and clinical improvement, 3 remained stable, and 1 had the treatment stopped because of clinical aggravation. At day 0, mean plasma serotonin (5-hydroxytryptamine [5-HT]) concentration was much higher in PPH patients than in normal subjects (34.4+/-21.2 versus 9.1+/-6.0 nmol/L, respectively; P:<0.001) and positively correlated with total pulmonary resistance. The mean platelet 5-HT content was not significantly different in PPH compared with normal individuals. Mean plasma 5-HIAA concentrations were much higher in PPH than in normal patients (162+/-57 versus 61+/-7 nmol/L, respectively; P<0.001). These parameters did not significantly change during epoprostenol treatment. There was no correlation between the changes in plasma 5-HT during treatment and clinical or hemodynamic improvement. In PPH patients, the mean platelet volume significantly decreased (ANOVA, P<0.01) during treatment. Positive correlations were evidenced between the size of platelets and the number of alpha(IIb)beta(3) and CD36 epitopes. When compared with control platelets, the number of alpha(IIb)beta(3) epitopes detected on PPH platelets at day 0 tended to be higher, but this difference did not reach a statistical significance (41 300+/-7140 for PPH patients versus 36 010+/-3930 for control subjects, P=0.069). The number of CD36 epitopes, in the range of controls at day 0 (11 590+/-5080 for PPH patients versus 11 900+/-1790 for control subjects), decreased during treatment (ANOVA, P=0.038) and became significantly low at day 40 (8660+/-3520, P<0.001). The number of CD63 epitopes was not elevated, and P-selectin was never detected at any time point on PPH platelets. This glycoprotein profile indicates that the platelets of PPH patients were not highly activated but had an accelerated turnover and returned to normal under epoprostenol treatment without change of the elevated plasma serotonin, characteristic of PPH. In conclusion, neither platelet activation nor a significant alteration of the 5-HT endothelial metabolism explains the high level of plasma 5-HT in PPH patients. The 5-HT plasma concentration is not a predictive marker of the severity of PPH, and its evolution is independent of the clinical and hemodynamic status. Treatment by a potent antiaggregating agent, epoprostenol, does not affect the increase of plasma 5-HT, despite a therapeutic benefit.

Signal transduction through prion protein.

The cellular prion protein PrPc is a glycosylphosphatidylinositol-anchored cell-surface protein whose biological function is unclear. We used the murine 1C11 neuronal differentiation model to search for PrPc-dependent signal transduction through antibody-mediated cross-linking. A caveolin-1-dependent coupling of PrPc to the tyrosine kinase Fyn was observed. Clathrin might also contribute to this coupling. The ability of the 1C11 cell line to trigger PrPc-dependent Fyn activation was restricted to its fully differentiated serotonergic or noradrenergic progenies. Moreover, the signaling activity of PrPc occurred mainly at neurites. Thus, PrPc may be a signal transduction protein.

Serotonin 2B receptor is required for heart development.

Several lines of evidence suggest that the serotonin (5-hydroxytryptamine, 5-HT) regulates cardiovascular functions during embryogenesis and adulthood. 5-HT binds to numerous cognate receptors to initiate its biological effects. However, none of the 5-HT receptor disruptions in mice have yet resulted in embryonic defects. Here we show that 5-HT(2B) receptor is an important regulator of cardiac development. We found that inactivation of 5-HT(2B) gene leads to embryonic and neonatal death caused by heart defects. 5-HT(2B) mutant embryos exhibit a lack of trabeculae in the heart and a specific reduction in the expression levels of a tyrosine kinase receptor, ErbB-2, leading to midgestation lethality. These in vivo data suggest that the Gq-coupled receptor 5-HT(2B) uses the signaling pathway of tyrosine kinase receptor ErbB-2 for cardiac differentiation. All surviving newborn mice display a severe ventricular hypoplasia caused by impaired proliferative capacity of myocytes. In adult mutant mice, cardiac histopathological changes including myocyte disarray and ventricular dilation were consistently observed. Our results constitute genetic evidence that 5-HT via 5-HT(2B) receptor regulates differentiation and proliferation of developing and adult heart. This mutation provides a genetic model for cardiopathy and should facilitate studies of both the pathogenesis and therapy of cardiac disorders in humans.

Functional expression of P-glycoprotein and multidrug resistance-associated protein (Mrp1) in primary cultures of rat astrocytes.

Although it has been well established that the drug efflux pump P-glycoprotein (P-gp) protects the brain against the entry of cytotoxic drugs, its real in situ localization, i.e., at brain capillary endothelial cells or on astrocyte foot processes, is still controversial. The aim of this study was to compare the expression of P-gp and of multidrug resistance-associated protein (Mrp1), another drug efflux pump, in cultured neonatal rat brain astrocytes and in cultured brain capillary endothelial cells. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis showed that the mdr1b gene was preferentially expressed in astrocytes, whereas both mdr1a and mdr1b mRNA were detected in endothelial cells. Moreover, the mrp1 gene encoding Mrp1 was expressed in both cell types. Western blotting analysis revealed higher expression of P-gp in endothelial cells as compared with astrocytes, but higher expression of Mrp1 in astrocytes. Moreover, P-gp and Mrp1 expression was not modified in more differentiated astrocytes obtained when cultured with db-cAMP for 48 hr. Our functional analysis of P-gp showed a modest effect of P-gp modulators (CsA, verapamil, PSC 833) on the uptake of colchicine (a substrate of P-gp) by astrocytes, whereas they increased by about 50% the uptake of vincristine (a common substrate of P-gp and MRP) by astrocytes. MRP modulators (genistein, probenecid, and sulfinpyrazone) did not modify the uptake of colchicine but increased that of vincristine with a major effect found for sulfinpyrazone. Moreover, indomethacin, probenecid, and sulfinpyrazone increased the uptake of fluorescein (a substrate of MRP but not of P-gp). Taken together, our results provide the first biochemical and functional evidence supporting the expression of P-gp and Mrp1 in rat cultured astrocytes.

PDZ-dependent activation of nitric-oxide synthases by the serotonin 2B receptor.

Taking advantage of three cellular systems, we established that 5-HT(2B) receptors are coupled with NO signaling pathways. In the 1C11 serotonergic cell line and Mastomys natalensis carcinoid cells, which naturally express the 5-HT(2B) receptor, as well as in transfected LMTK(-) fibroblasts, stimulation of the 5-HT(2B) receptor triggers intracellular cGMP production through dual activation of constitutive nitric-oxide synthase (cNOS) and inducible NOS (iNOS). The group I PDZ motif at the C terminus of the 5-HT(2B) receptor is required for recruitment of the cNOS and iNOS transduction pathways. Indeed, the 5-HT(2B) receptor-mediated NO coupling is abolished not only upon introduction of a competitor C-terminal 5-HT(2B) peptide in the three cell types but also in LMTK(-) fibroblasts expressing a receptor C-terminally truncated or harboring a point mutation within the PDZ domain. The occurrence of a direct functional coupling between the receptor and cNOS activity is supported by highly significant correlations between the binding constants of drugs on the receptor and their effects on cNOS activity. The 5-HT(2B)/iNOS coupling mechanisms appear more complex because neutralization of endogenous Galpha(13) by specific antibodies cancels the cellular iNOS response while not interfering with cNOS activities. These findings may shed light on physiological links between the 5-HT(2B) receptor and NO and constitute the first demonstration that PDZ interactions participate in downstream transductional pathways of a G protein-coupled receptor.

5-hydroxytryptamine 2B receptor regulates cell-cycle progression: cross-talk with tyrosine kinase pathways.

In this paper, we present evidence that activation of 5-hydroxytryptamine 2B (5-HT2B) receptors by serotonin (5-HT) leads to cell-cycle progression through retinoblastoma protein hyperphosphorylation and through activation of both cyclin D1/cdk4 and cyclin E/cdk2 kinases by a mechanism that depends on induction of cyclin D1 and cyclin E protein levels. The induction of cyclin D1 expression, but not that of cyclin E, is under mitogen-activated protein kinase (MAPK) control, indicating an independent regulation of these two cyclins in the 5-HT2B receptor mitogenesis. Moreover, by using the specific platelet-derived growth factor receptor (PDGFR) inhibitor AG 1296 or by overexpressing a kinase-mutant PDGFR, we show that PDGFR kinase activity is essential for 5-HT2B-triggered MAPK/cyclin D1, but not cyclin E, signaling pathways. 5-HT2B receptor activation also increases activity of the Src family kinase, c-Src, Fyn, and c-Yes. Strikingly, c-Src, but not Fyn or c-Yes, is the crucial molecule between the G(q) protein-coupled 5-HT2B receptor and the cell-cycle regulators. Inhibition of c-Src activity by 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1) or depletion of c-Src is sufficient to abolish the 5-HT-induced (i) PDGFR tyrosine kinase phosphorylation and MAPK activation, (ii) cyclin D1 and cyclin E expression levels, and (iii) thymidine incorporation. This paper elucidates a model of 5-HT2B receptor mitogenesis in which c-Src acts alone to control cyclin E induction and in concert with the receptor tyrosine kinase PDGFR to induce cyclin D1 expression via the MAPK/ERK pathway.

Decreased platelet serotonin transporter sites and increased platelet inositol triphosphate levels in patients with unipolar depression: effects of clomipramine and fluoxetine.

BACKGROUND: The central serotonergic system has been implicated in the pathophysiology of depression and in the mechanism of the action of antidepressant drugs. The human platelet has been proposed as a peripheral model of central serotonergic neurons. METHODS: Six peripheral serotonergic parameters were determined simultaneously in 27 patients with unipolar depression before and after 2, 4, and 12 weeks of clomipramine or fluoxetine treatment according to the psychiatrist. RESULTS: In patients with depression versus matched control subjects, platelet [3H]paroxetine binding sites were found to be significantly decreased (2.10 +/- 0.70 versus 3.88 +/- 0.77 fmol/10(9) platelets; P = .0001), platelet serotonin (5-HT) content was found to be significantly decreased (1.90 +/- 1.52 versus 2.74 +/- 1.12 nmol/10(9) platelets; P = .001), and platelet inositol triphosphate levels were found to be significantly increased (2.85 +/- 0.70 versus 1.85 +/- 0.77 fmol/10(9) platelets; P = .0001). No significant difference between patients and control subjects was found for platelet [3H]-lysergic acid diethylamide ([3H]LSD) binding sites, aggregation tests with 5-HT or adenosine diphosphate and plasma 5-HT levels. Treatment with both clomipramine and fluoxetine gradually further reduced the density of platelet [3H]paroxetine binding sites and induced a dramatic decrease in platelet and plasma 5-HT levels. With clomipramine, the decreased blood 5-HT levels are associated with increased platelet [3H]LSD binding sites and aggregation responses. After 12 weeks, nonresponders to both treatments had platelet inositol triphosphate levels that were still increased (2.81 +/- 0.75 fmol/10(9) platelets) when responders levels were not different from those of control subjects (1.41 +/- 0.45 versus 1.70 +/- 0.25 fmol/10(9) platelets). CONCLUSIONS: Drug-free patients with depression had simultaneously decreased 5-HT transporter (5-HTT) sites and overstimulated phosphoinositide signaling systems. Clomipramine and fluoxetine treatments, which further decreased the density of 5-HTT sites, allowed platelet inositol triphosphate levels to return to normal values only in responders.