Mutations of the Serine Protease CAP1/Prss8 Lead to Reduced Embryonic Viability, Skin Defects, and Decreased ENaC Activity.

CAP1/Prss8 is a membrane-bound serine protease involved in the regulation of several different effectors, such as the epithelial sodium channel ENaC, the protease-activated receptor PAR2, the tight junction proteins, and the profilaggrin polypeptide. Recently, the V170D and the G54-P57 deletion mutations within the CAP1/Prss8 gene, identified in mouse frizzy (fr) and rat hairless (fr(CR)) animals, respectively, have been proposed to be responsible for their skin phenotypes. In the present study, we analyzed those mutations, revealing a change in the protein structure, a modification of the glycosylation state, and an overall reduction in the activation of ENaC of the two mutant proteins. In vivo analyses demonstrated that both fr and fr(CR) mutant animals present analogous reduction of embryonic viability, similar histologic aberrations at the level of the skin, and a significant decrease in the activity of ENaC in the distal colon compared with their control littermates. Hairless rats additionally had dehydration defects in skin and intestine and significant reduction in the body weight. In conclusion, we provided molecular and functional evidence that CAP1/Prss8 mutations are accountable for the defects in fr and fr(CR) animals, and we furthermore demonstrate a decreased function of the CAP1/Prss8 mutant proteins. Therefore, fr and fr(CR) animals are suitable models to investigate the consequences of CAP1/Prss8 action on its target proteins in the whole organism.

A stable phage lysin (Cpl-1) dimer with increased antipneumococcal activity and decreased plasma clearance.

Bacteriophages (phages) produce endolysins (lysins) as part of their lytic cycle in order to degrade the peptidoglycan layer of the infected bacteria for subsequent release of phage progeny. Because these enzymes maintain their lytic and lethal activity against Gram-positive bacteria when added extrinsically to the cells, they have been actively exploited as novel anti-infectives, sometimes termed enzybiotics. As with other relatively small peptides, one issue in their clinical development is their rapid inactivation through proteolytic degradation, immunological blockage and renal clearance. The antipneumococcal lysin Cpl-1 was shown to escape both proteolysis and immunological blockage. However, its short plasma half-life (20.5 min in mice) may represent a shortcoming for clinical usefulness. Here we report the construction of a Cpl-1 dimer with a view to increasing both the antipneumococcal specific activity and plasma half-life of Cpl-1. Dimerisation was achieved by introducing specific cysteine residues at the C-terminal end of the enzyme, thus favouring disulphide bonding. Compared with the native monomer, the constructed dimer demonstrated a two-fold increase in specific antipneumococcal activity and a ca. ten-fold decrease in plasma clearance. As several lysins are suspected to dimerise on contact with their cell wall substrate to be fully active, stable pre-dimerised enzymes may represent a more efficient alternative to the native monomer.

Agenesis of human pancreas due to decreased half-life of insulin promoter factor 1.

Neonatal diabetes mellitus can be transient or permanent. The severe form of permanent neonatal diabetes mellitus can be associated with pancreas agenesis. Normal pancreas development is controlled by a cascade of transcription factors, where insulin promoter factor 1 (IPF1) plays a crucial role. Here, we describe two novel mutations in the IPF1 gene leading to pancreas agenesis. Direct sequence analysis of exons 1 and 2 of the IPF1 gene revealed two point mutations within the homeobox in exon 2. Genetic analysis of the parents showed that each mutation was inherited from one parent. Mutations localized in helices 1 and 2, respectively, of the homeodomain, decreased the protein half-life significantly, leading to intracellular IPF1 levels of 36% and 27% of wild-type levels. Both mutant forms of IPF1 were normally translocated to the nucleus, and their DNA binding activity on different known target promoters was similar to that of the wild-type protein. However, transcriptional activity of both mutant IPF1 proteins, alone or in combination with HNF3 beta/Foxa2, Pbx1, or the heterodimer E47-beta 2 was reduced, findings accounted for by decreased IPF1 steady state levels and not by impaired protein-protein interactions. We conclude that the IPF1 level is critical for human pancreas formation.

The impact of iron supplementation efficiency in female blood donors with a decreased ferritin level and no anaemia. Rationale and design of a randomised controlled trial: a study protocol.

ABSTRACT: BACKGROUND: There is no recommendation to screen ferritin level in blood donors, even though several studies have noted the high prevalence of iron deficiency after blood donation, particularly among menstruating females. Furthermore, some clinical trials have shown that non-anaemic women with unexplained fatigue may benefit from iron supplementation. Our objective is to determine the clinical effect of iron supplementation on fatigue in female blood donors without anaemia, but with a mean serum ferritin </= 30 ng/ml. METHODS/DESIGN: In a double blind randomised controlled trial, we will measure blood count and ferritin level of women under age 50 yr, who donate blood to the University Hospital of Lausanne Blood Transfusion Department, at the time of the donation and after 1 week. One hundred and forty donors with a ferritin level </= 30 ng/ml and haemoglobin level >/= 120 g/l (non-anaemic) a week after the donation will be included in the study and randomised. A one-month course of oral ferrous sulphate (80 mg/day of elemental iron) will be introduced vs. placebo. Self-reported fatigue will be measured using a visual analogue scale. Secondary outcomes are: score of fatigue (Fatigue Severity Scale), maximal aerobic power (Chester Step Test), quality of life (SF-12), and mood disorders (Prime-MD). Haemoglobin and ferritin concentration will be monitored before and after the intervention. DISCUSSION: Iron deficiency is a potential problem for all blood donors, especially menstruating women. To our knowledge, no other intervention study has yet evaluated the impact of iron supplementation on subjective symptoms after a blood donation. TRIAL REGISTRATION: NCT00689793.

Decreased compliance on arterial anastomoses.

The present study was undertaken to examine the cross-sectional vascular compliance at the anastomotic site. METHODS AND MATERIAL: We performed end-to-end anastomosis on the carotid artery of six pigs using continuous 6/0 polypropylene. Four carotid arteries were excised and mounted in a perfusion chamber while the remaining two were left in living animals. We used pulsed ultrasound (NIUS 02) to generate detailed longitudinal profiles of diameter and compliance in the proximity and on the anastomosis. RESULTS: On the anastomosis, the vessel diameter decreases (-1 to -2.6% of diastolic diameter) when blood pressure increases with an exponential correlation (R2 = 0.75). The arterial compliance at the anastomosis was negative: the vessel cross-section reduction for a pulse pressure of 1 up to 32 mmHg was 0.9 to 2% of diastolic vessel cross-section. CONCLUSIONS: Vessel movement generated a dynamic stenosis whose magnitude seems to depend on blood pressure level. Increasing blood pressure causes the retraction of vessel ends which causes vessel lumen reduction. These results suggest that continuous suture does not provide the continuity of mechanical properties of the artery.

Loss of connexin40 is associated with decreased endothelium-dependent relaxations and eNOS levels in the mouse aorta.

Upon agonist stimulation, endothelial cells trigger smooth muscle relaxation through the release of relaxing factors such as nitric oxide (NO). Endothelial cells of mouse aorta are interconnected by gap junctions made of connexin40 (Cx40) and connexin37 (Cx37), allowing the exchange of signaling molecules to coordinate their activity. Wild-type (Cx40(+/+)) and hypertensive Cx40-deficient mice (Cx40(-/-)), which also exhibit a marked decrease of Cx37 in the endothelium, were used to investigate the link between the expression of endothelial connexins (Cx40 and Cx37) and endothelial nitric oxide synthase (eNOS) expression and function in the mouse aorta. With the use of isometric tension measurements in aortic rings precontracted with U-46619, a stable thromboxane A(2) mimetic, we first demonstrate that ACh- and ATP-induced endothelium-dependent relaxations solely depend on NO release in both Cx40(+/+) and Cx40(-/-) mice, but are markedly weaker in Cx40(-/-) mice. Consistently, both basal and ACh- or ATP-induced NO production were decreased in the aorta of Cx40(-/-) mice. Altered relaxations and NO release from aorta of Cx40(-/-) mice were associated with lower expression levels of eNOS in the aortic endothelium of Cx40(-/-) mice. Using immunoprecipitation and in situ ligation assay, we further demonstrate that eNOS, Cx40, and Cx37 tightly interact with each other at intercellular junctions in the aortic endothelium of Cx40(+/+) mice, suggesting that the absence of Cx40 in association with altered Cx37 levels in endothelial cells from Cx40(-/-) mice participate to the decreased levels of eNOS. Altogether, our data suggest that the endothelial connexins may participate in the control of eNOS expression levels and function.

Decreased local control following radiation therapy alone in early-stage glottic carcinoma with anterior commissure extension.

PURPOSE: To assess the patterns of failure in the treatment of early-stage squamous cell carcinoma of the glottic larynx. PATIENTS AND METHODS: Between 1983-2000, 122 consecutive patients treated for early laryngeal cancer (UICC T1N0 and T2N0) by radical radiation therapy (RT) were retrospectively studied. Male-to-female ratio was 106 : 16, and median age 62 years (35-92 years). There were 68 patients with T1a, 18 with T1b, and 36 with T2 tumors. Diagnosis was made by biopsy in 104 patients, and by laser vaporization or stripping in 18. Treatment planning consisted of three-dimensional (3-D) conformal RT in 49 (40%) patients including nine patients irradiated using arytenoid protection. A median dose of 70 Gy (60-74 Gy) was given (2 Gy/fraction) over a median period of 46 days (21-79 days). Median follow-up period was 85 months. RESULTS: The 5-year overall, cancer-specific, and disease-free survival amounted to 80%, 94%, and 70%, respectively. 5-year local control was 83%. Median time to local recurrence in 19 patients was 13 months (5-58 months). Salvage treatment consisted of surgery in 17 patients (one patient refused salvage and one was inoperable; total laryngectomy in eleven, and partial laryngectomy or cordectomy in six patients). Six patients died because of laryngeal cancer. Univariate analyses revealed that prognostic factors negatively influencing local control were anterior commissure extension, arytenoid protection, and total RT dose < 66 Gy. Among the factors analyzed, multivariate analysis (Cox model) demonstrated that anterior commissure extension, arytenoid protection, and male gender were the worst independent prognostic factors in terms of local control. CONCLUSION: For early-stage laryngeal cancer, outcome after RT is excellent. In case of anterior commissure extension, surgery or higher RT doses are warranted. Because of a high relapse risk, arytenoid protection should not be attempted.

Is lean body mass decreased after obesity treatment by adjustable gastric banding?

BACKGROUND: There is concern that surgically-induced weight loss in obese subjects is associated with a disproportionate decrease in lean body mass (LBM) and in skeletal muscle mass (SMM), a major constituent of LBM. To address this issue, 1) we measured total and regional body composition following gastric banding in a group of obese subjects, and 2) we compared these data to those of a non-surgical control group of similar age and body size. METHODS: Body composition was assessed by dual-energy X-ray absorptiometry (DEXA) before and after laparoscopic adjustable silicone gastric banding (LAGB) in 32 women (after 1 year: age 43.7+/-8.4 years, BMI 36.4+/-5.9 kg/m2, mean+/-SD), and in 117 control women (age 44.5+/-7.5 years; BMI 36.7+/-5.5 kg/m2) referred for non-surgical weight management, prior to weight loss. SMM was estimated using a published equation based on LBM of the extremities (appendicular LBM). RESULTS: 1 year after LAGB, body weight loss (-23.7+/-11.6 kg, P<10(-6)) was mainly due to decreased fat mass (-21.2+/-11.2 kg, P<10(-6)), and total LBM was modestly, although significantly, decreased (-2.1+/-4.2 kg, P=0.01). Appendicular LBM (-0.7+/-2.7 kg) and total SMM (-0.9+/-3.0 kg) were not significantly modified. None of the body composition variables was significantly decreased in weight-reduced subjects compared to the control group, especially appendicular LBM and total SMM. CONCLUSIONS: Results provide no evidence for a decrease in appendicular LBM and total SMM with weight loss following LAGB. Follow-up of these obese patients revealed a very favorable pattern of change in total and regional body composition, with preservation of muscle mass.

Decreased expression of peroxisome proliferator-activated receptor alpha and liver fatty acid binding protein after partial hepatectomy of rats and mice.

BACKGROUND AIMS: Marked changes in metabolism, including liver steatosis and hypoglycemia, occur after partial hepatectomy. Peroxisome proliferator-activated receptor alpha (PPAR alpha) is a nuclear hormone receptor that is activated by fatty acids and involved in hepatic fatty acid metabolism and regeneration. Liver fatty acid binding protein (LFABP) is an abundant protein in liver cytosol whose expression is regulated by PPAR alpha. It is involved in fatty acid uptake and diffusion and in PPAR alpha signaling. The aim of this study was to investigate the expression of PPAR alpha and LFABP during liver regeneration. METHODS: Male Sprague-Dawley rats and male C57 Bl/6 mice were subjected to 2/3 hepatectomy and LFABP and PPAR alpha mRNA and protein levels were measured at different time points after surgery. The effect of partial hepatectomy was followed during 48 h in rats and 72 h in mice. RESULTS: PPAR alpha mRNA and protein levels were decreased 26 h after hepatectomy of rats. The LFABP mRNA and protein levels paralleled those of PPAR alpha and were also decreased 26 h after hepatectomy. In mice, the mRNA level was decreased after 36 and 72 h after hepatectomy. In this case, LFABP mRNA levels decreased more slowly after partial hepatectomy than in rats. CONCLUSIONS: A marked decrease in PPAR alpha expression may be important for changed gene expression, e.g. LFABP, and metabolic changes, such as hypoglycemia, during liver regeneration.

Decreased PM10 exposure attenuates age-related lung function decline: genetic variants in p53, p21, and CCND1 modify this effect.

BACKGROUND: Decreasing exposure to airborne particulates was previously associated with reduced age-related decline in lung function. However, whether the benefit from improved air quality depends on genetic background is not known. Recent evidence points to the involvement of the genes p53 and p21 and of the cell cycle control gene cyclin D1 (CCND1) in the response of bronchial cells to air pollution. OBJECTIVE: We determined in 4,326 participants of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) whether four single-nucleotide polymorphisms in three genes [CCND1 (rs9344 [P242P], rs667515), p53 (rs1042522 [R72P]), and p21 (rs1801270 [S31R])] modified the previously observed attenuation of the decline in the forced expiratory flow between 25% and 75% of the forced vital capacity (FEF(25-75)) associated with improved air quality. METHODS: Subjects of the prospective population-based SAPALDIA cohort were assessed in 1991 and 2002 by spirometry, questionnaires, and biological sample collection for genotyping. We assigned spatially resolved concentrations of particulate matter with aerodynamic diameter < or = 10 microm (PM(10)) to each participant's residential history 12 months before the baseline and follow-up assessments. RESULTS: The effect of diminishing PM(10) exposure on FEF(25-75) decline appeared to be modified by p53 R72P, CCND1 P242P, and CCND1 rs667515. For example, a 10-microg/m(3) decline in average PM(10) exposure over an 11-year period attenuated the average annual decline in FEF(25-75) by 21.33 mL/year (95% confidence interval, 10.57-32.08) among participants homozygous for the CCND1 (P242P) GG genotype, by 13.72 mL/year (5.38-22.06) among GA genotypes, and by 6.00 mL/year (-4.54 to 16.54) among AA genotypes. CONCLUSIONS: Our results suggest that cell cycle control genes may modify the degree to which improved air quality may benefit respiratory function in adults.

A neuron-specific deletion of the microRNA-processing enzyme DICER induces severe but transient obesity in mice.

MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate gene expression post-transcriptionally. MiRNAs are implicated in various biological processes associated with obesity, including adipocyte differentiation and lipid metabolism. We used a neuronal-specific inhibition of miRNA maturation in adult mice to study the consequences of miRNA loss on obesity development. Camk2a-CreERT2 (Cre+) and floxed Dicer (Dicerlox/lox) mice were crossed to generate tamoxifen-inducible conditional Dicer knockouts (cKO). Vehicle- and/or tamoxifen-injected Cre+;Dicerlox/lox and Cre+;Dicer+/+ served as controls. Four cohorts were used to a) measure body composition, b) follow food intake and body weight dynamics, c) evaluate basal metabolism and effects of food deprivation, and d) assess the brain transcriptome consequences of miRNA loss. cKO mice developed severe obesity and gained 18 g extra weight over the 5 weeks following tamoxifen injection, mainly due to increased fat mass. This phenotype was highly reproducible and observed in all 38 cKO mice recorded and in none of the controls, excluding possible effects of tamoxifen or the non-induced transgene. Development of obesity was concomitant with hyperphagia, increased food efficiency, and decreased activity. Surprisingly, after reaching maximum body weight, obese cKO mice spontaneously started losing weight as rapidly as it was gained. Weight loss was accompanied by lowered O2-consumption and respiratory-exchange ratio. Brain transcriptome analyses in obese mice identified several obesity-related pathways (e.g. leptin, somatostatin, and nemo-like kinase signaling), as well as genes involved in feeding and appetite (e.g. Pmch, Neurotensin) and in metabolism (e.g. Bmp4, Bmp7, Ptger1, Cox7a1). A gene cluster with anti-correlated expression in the cerebral cortex of post-obese compared to obese mice was enriched for synaptic plasticity pathways. While other studies have identified a role for miRNAs in obesity, we here present a unique model that allows for the study of processes involved in reversing obesity. Moreover, our study identified the cortex as a brain area important for body weight homeostasis.

Decreased well-being after job loss : testing omitted causes

Job loss is widely known to lead to a substantial decrease in workers' subjective well-being. Functionalist theories explain this fact by arguing that the fundamental needs that work fulfills are absent during unemployment. Recent evidence from longitudinal studies however contradicts this approach, showing that workers who find a new job do not fully regain their former level of well-being upon reemployment. Therefore other mechanisms must be at work. We suggest that changes in social or economic domains of workers' lives - triggered by job displacement - lead to the observed changes in well-being. Drawing on a unique data set from a survey of workers displaced by plant closure in Switzerland after the financial crisis of 2008, our analysis confirms the previous result that finding a job after displacement does not completely restore workers' pre-displacement level of well-being. The factors that best explain this outcome are changes in social domains, notably changes in workers' job - related social status and their relationships to friends. This result provides valuable insights about the long lasting scars job displacement leaves on workers' lives.

Decreased specific CD8+ T cell cross-reactivity of antigen recognition following vaccination with Melan-A peptide.

The aim of T cell vaccines is the expansion of antigen-specific T cells able to confer immune protection against pathogens or tumors. Although increase in absolute cell numbers, effector functions and TCR repertoire of vaccine-induced T cells are often evaluated, their reactivity for the cognate antigen versus their cross-reactive potential is rarely considered. In fact, little information is available regarding the influence of vaccines on T cell fine specificity of antigen recognition despite the impact that this feature may have in protective immunity. To shed light on the cross-reactive potential of vaccine-induced cells, we analyzed the reactivity of CD8(+) T cells following vaccination of HLA-A2(+) melanoma patients with Melan-A peptide, incomplete Freund's adjuvant and CpG-oligodeoxynucleotide adjuvant, which was shown to induce strong expansion of Melan-A-reactive CD8(+) T cells in vivo. A collection of predicted Melan-A cross-reactive peptides, identified from a combinatorial peptide library, was used to probe functional antigen recognition of PBMC ex vivo and Melan-A-reactive CD8(+) T cell clones. While Melan-A-reactive CD8(+) T cells prior to vaccination are usually constituted of widely cross-reactive naive cells, we show that peptide vaccination resulted in expansion of memory T cells displaying a reactivity predominantly restricted to the antigen of interest. Importantly, these cells are tumor-reactive.

Decreased acute vascular remodeling, anaphylaxis and delayed type hypersensitivity in PPARβ/δ-deficient mice

Endothelial cells form a semi-permeable barrier that participates in the exchange of plasma fluids, proteins and cells, and helps to maintain the physiological functions of organs as well as circulatory homeostasis. Vascular permeability and vasodilatation are increased during acute and chronic inflammation, cancer and wound healing. This is mediated by exposure to certain vascular permeability increasing factors, such as vascular endothelial growth factor (VEGF). The peroxisome proliferator-activated receptors (PPAR) belong to the nuclear hormone receptor (NHRs) family of ligand-activated transcription factors. Three isotypes, PPARa, PPARp/5 and PPARy have been identified. They are all expressed in endothelial cells (ECs). Recent data have demonstrated their involvement in important mechanisms for vasculogenesis and angiogenesis, such as cell proliferation/differentiation, directional sensing/migration, and survival. PPARs were reported to modulate the expression of pro-angiogenic soluble factors, such as VEGF-A and may also participate in the regulation of expression of VEGF receptors. The aim of the present work was to elucidate the role of PPARp/δ in endothelial cell functions important for angiogenesis as well as in vascular permeability and vasodilatation. Using organ culture models of mouse aorta expiants, cultures of human umbilical vein endothelial cells (HUVECs) and genetically modified mouse models, we studied the consequences of loss and gain of PPARp/5 activity on endothelial cell functions. In the first part of this study, we show that the activation of PPARp/δ promotes EC outgrowth in murine aorta expiants. In vivo we observed that dermal vessel acute permeability in response to VEGF-A stimulation is strongly impaired in PPARfi/δ -I- animals. Additionally, observation of the dermal vessel morphology showed a clear enlargement of the wild-type dermal vessels upon VEGF-A injection, whereas vessels of PPARp/5 -/- animals showed almost no enlargement. The impaired response to VEGF stimulation in the knock-out animals was not due to structural or morphological abnormalities. Based on this data, we suggest that PPARp/5 may act on intracellular signaling cascades in ECs, downstream of the VEGF-A receptor. In the second part of this study, we address the relevance of PPARβ/δ vascular functions in pathophysiological inflammatory conditions, such as delayed- type hypersensitivity (DTH) reaction and anaphylaxis in mice. The DTH reaction is a cell-mediated immune reaction to protein, bacterial and viral antigens, whereas anaphylaxis is the most severe form of allergic reaction. In these in vivo models, we demonstrated that the absence of PPARβ/δ in ECs prevents the formation of severe edema in the DTH reaction, and that Ρ PARβ/δ accelerates recovery following systemic anaphylaxis, at least partially through the control of vascular permeability. Our data not only describe a novel function of PPARβ/δ in vessel permeability and vasodilatation, but also open new routes of research for the development of vessel permeability/vasodilatation regulating agents. - Les cellules endothéliales qui bordent la face interne des vaisseaux sanguins forment l'endothélium, une barrière semi-perméable qui régule les échanges de fluides, de protéines et de cellules immunes entre la circulation et les organes. L'endothélium participe également au maintien de la fonction des organes et de l'homéostasie circulatoire. La perméabilité vasculaire augmente dans des situations inflammatoires aigties ou chroniques, dans les tumeurs, et pendant la réparation de blessures. Cette augmentation de perméabilité est due à la production de facteurs sécrétés, tels que le Vascular Endothelial Growth Factor (VEGF-A), la thrombine ou I'histamine. Lès récepteurs nucléaires Peroxisome Proliferator-Activated Receptors (PPAR) sont des facteurs de transcription mis en activité par des ligands. Trois isotypes de PPARs, PPARa, ΡΡΑΡβ/δ and PPARy ont été caractérisés. Ils sont exprimés dans les cellules endothéliales, et des travaux récents ont montré qu'ils régulent des comportements cellulaires importants pour la vasculogenèse et l'angiogenèse, tels que la prolifération, la différenciation, la migration, et la survie des cellules. Ils régulent également la production de VEGF-A par divers types cellulaires. Le but de ce travail était d'élucider le rôle de PPARβ/δ dans la régulation de la perméabilité vasculaire, plus particulièrement dans les cellules endothéliales. Grâce à des cultures d'expiants d'aortes de souris, à la culture d'une lignée endothéliale humaine (HUVECs) et de souris génétiquement modifiées, nous avons étudié le rôle de PPARβ/δ dans les cellules endothéliales, dans des situations gain et perte de fonction du récepteur. Dans la première partie de ce travail, nous avons montré les propriétés pro-angiogéniques de PPARβ/δ dans des explants d'aortes. In vivo, nous avons observé l'absence d'hyperperméabilité aiguë induite par le VEGF-A, la thrombine et I'histamine chez les souris PPARβ/δ -/-. De plus, l'analyse morphologique des vaisseaux dans le derme des souris après stimulation par VEGF- A a confirmé l'absence de réponse à la stimulation. Ces analyses morphologiques nous ont également permis de montrer que l'absence de réponse aiguë n'était pas due à un défaut de structure des vaisseaux dermiques chez les souris PPARp/δ -/-. Sur la base de ces résultats, nous proposons que PPARp/δ régule des voies de signalisation intracellulaires dans les cellules endothéliales, voie de signalisation impliquées dans la régulation de la perméabilité vasculaire: Dans la seconde partie du travail, nous avons étudié l'importance de la régulation de la perméabilité vasculaire par PPARβ/δ dans des situations pathophysiologiques impliquant une hyperperméabilité aiguë des vaisseaux : une réaction d'hypersensibilité cutanée retardée d'une part (delayed-type hypersensitivity, DTH), et un choc anaphylactique d'autre part. Dans ces deux modèles induits expérimentalement chez la souris, l'absence de PPARβ/δ prévient en partie la formation de l'oedème inflammatoire local (DTH), et accélère la récupération (anaphylaxie), au moins partiellement en réglant la perméabilité vasculaire. Ces résultats ouvrent un nouveau champs d'étude quant au rôle de PPARβ/δ dans les vaisseaux et à d'éventuelles applications thérapeutiques dans des pathologies inflammatoires.

Methadone blood concentrations are decreased by the administration of abacavir plus amprenavir.

Abacavir and amprenavir, a nucleoside reverse transcription inhibitor and a protease inhibitor, respectively, are new drugs used for the treatment of HIV. Methadone blood concentrations were measured in five addict patients receiving methadone maintenance therapy before and after introduction of abacavir plus amprenavir. The administration of these two drugs for a median period of 14 days resulted in a significant reduction (P = 0.043) of methadone concentration, with a median decrease to 35% of the original concentration (range 28-87%). Two patients reported on several occasions nausea in the morning before the intake of the daily methadone dose, which is compatible with withdrawal reaction to opioids. Because amprenavir is a cytochrome P4503A4 substrate and is involved in the metabolism of methadone, reduction of methadone concentrations could be explained by an induction of cytochrome P4503A4.