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Biomedical subjects

P Gourdy

Publications and source records attributed to P Gourdy.

13 recordsLinked to original sources
PubMed2006

Treatment of experimental murine pancreatic peritoneal carcinomatosis with fibroblasts genetically modified to express IL12: a role for peritoneal innate immunity.

BACKGROUND: Peritoneal carcinomatosis from pancreatic cancer has a poor prognosis with a median survival of 3.1 months. This is mainly due to lack of effective treatment. Interleukin 12 (IL12) is a proinflammatory cytokine that has a potent antitumoral effect by stimulating innate and adoptive immunity. AIM: To examine the antitumoral effect and toxicity of intraperitoneal delivery of IL12 using an ex vivo gene therapy approach in a murine model of pancreatic peritoneal carcinomatosis. METHODS: Peritoneal carcinomatosis was generated by direct intraperitoneal inoculation of the pancreatic cancer cell line Capan-1 in athymic mice. Syngenic fibroblasts were genetically modified in vitro to secrete IL12 using a polycistronic TFG murine IL12 retroviral vector coding for both p35 and p40 murine IL12 subunits. Ex vivo gene therapy involved injection of the genetically modified fibroblasts intraperitoneally twice a week for 4 weeks. RESULTS: Treatment of pre-established peritoneal carcinomatosis with fibroblasts genetically modified to express IL12 induced a marked inhibition of tumour growth as measured by comparison of the weights of the intraperitoneal tumour nodules in the treated and control animals (3.52 (SD 0.47) v 0.93 (SD 0.21) g, p<0.05) and improved survival. This effect was associated with infiltration of the peritoneal tumour nodules with macrophages. Peritoneal lavage confirmed enhancement of the innate peritoneal inflammatory activity, with an increased number of activated macrophages and natural killer cells. Moreover, macrophages harvested from animals with peritoneal carcinomatosis and treated with IL12-expressing fibroblasts expressed an activated proinflammatory antitumoral M1 phenotype that included strongly enhanced reactive oxygen species and nitric oxide production. There was no treatment-related toxicity. CONCLUSION: Multiple injections of genetically modified fibroblasts to express IL12 is an effective and well-tolerated treatment for experimental murine pancreatic peritoneal carcinomatosis via activated innate immunity and in particular activated M1 macrophages.

Animals↗
PubMed2006

Understanding the oestrogen action in experimental and clinical atherosclerosis.

Whereas hormone replacement/menopause therapy (HRT) in postmenopausal women increases the coronary artery risk, epidemiological studies (protection in premenopaused women) suggest and experimental studies (prevention of the development of fatty streaks in animals) demonstrate a major atheroprotective action of oestradiol (E2). The understanding of the deleterious and beneficial effects of oestrogens is thus required. The immuno-inflammatory system plays a key role in the development of fatty streak deposit as well as in the rupture of the atherosclerotic plaque. Whereas E2 favours an anti-inflammatory effect in vitro (cultured cells), it rather elicits in vivo a proinflammation at the level of several subpopulations of the immuno-inflammatory system, which could contribute to plaque destabilization. Endothelium is another important target for E2, as it potentiates endothelial NO and prostacyclin production, thus promoting the beneficial effects as vasorelaxation and inhibition of platelet aggregation. Prostacyclin, but not NO, appears to be involved in the atheroprotective effect of E2. E2 also accelerates endothelial regrowth, thus favouring vascular healing. Finally, most of these effects of E2 are mediated by oestrogen receptor alpha, and are independent of oestrogen receptor beta. In summary, a better understanding of the mechanisms of oestrogen action not only on the normal and atheromatous arteries, but also on innate and adaptive immune responses is required and should help to optimize the prevention of cardiovascular disease after menopause. These mouse models should help to screen existing and future selective oestrogen receptor modulators.

Animals↗
PubMed2004

Role of fibroblast growth factor-2 isoforms in the effect of estradiol on endothelial cell migration and proliferation.

Both 17beta-estradiol (E2) and fibroblast growth factor-2 (FGF2) stimulate angiogenesis and endothelial cell migration and proliferation. The first goal of this study was to explore the potential link between this hormone and this growth factor. E2-stimulated angiogenesis in SC Matrigel plugs in Fgf2+/+ mice, but not in Fgf2-/- mice. Cell cultures from subcutaneous Matrigel plugs demonstrated that E2 increased both migration and proliferation in endothelial cells from Fgf2+/+ mice, but not from in Fgf2-/- mice. Several isoforms of fibroblast growth factor-2 (FGF2) are expressed: the low molecular weight 18-kDa protein (FGF2lmw) is secreted and activates tyrosine kinase receptors (FGFRs), whereas the high molecular weight (21 and 22 kDa) isoforms (FGF2hmw) remains intranuclear, but their role is mainly unknown. The second goal of this study was to explore the respective roles of FGF2 isoforms in the effects of E2. We thus generated mice deficient only in the FGF2lmw (Fgf2lmw-/-). E2 stimulated in vivo angiogenesis and in vitro migration in endothelial cells from Fgf2lmw-/- as it did in Fgf2+/+ mice. E2 increased FGF2hmw protein abundance in endothelial cell cultures from Fgf2+/+ and Fgf2lmw-/- mice. As shown using siRNA transfection, these effects were FGFR independent but involved FGF2-Interacting Factor, an intracellular FGF2hmw partner. This is the first report for a physiological role for the intracellular FGF2hmw found to mediate the effect of E2 on endothelial cell migration via an intracrine action.

Animals↗
PubMed2004

Estrogens and atherosclerosis.

Numerous epidemiological as well as experimental studies have suggested that estradiol (E2) prevents atherosclerosis development. However two controlled prospective and randomized studies in women using hormone replacement therapy (HRT) did not confirm this beneficial effect. We then decided to use mouse models of atherosclerosis to define the possible mechanisms involved and the reasons for the discrepancy. We have shown that, although serum cholesterol decreases, this influence on lipid metabolism is negligible. Surprisingly, E2 induces an inflammatory-immune response towards a T helper cell (Th1) profile with increasing interferon-gamma production that could destabilize atheromatous plaques, and could account for the increase in the frequency of cardiovascular events in women undergoing HRT. At the level of the endothelium, E2 induces an increase in nitric oxide (NO) biodisponibility, but this phenomenon does not concern the development of fatty streaks. Nevertheless, the atheroprotective effect is apparently mediated at the level of the endothelium by a mechanism that has still to be characterized in molecular terms. These new acquisitions constitute a basis for new pharmacological developments allowing the prevention of deleterious effects and preserving the beneficial ones.

Animals↗
PubMed2003

Protective role of uncoupling protein 2 in atherosclerosis.

BACKGROUND: Uncoupling protein 2 (UCP2) regulates the production of reactive oxygen species in macrophages. However, its role in atherosclerosis is unknown. METHODS AND RESULTS: Irradiated low-density lipoprotein receptor deficient mice (LDLR-/-) were transplanted with bone marrow from either UCP2 deficient mice (Ucp2-/-) or wild type mice (Ucp2+/+). Mice were fed an atherogenic diet for 7 weeks. Engraftment of bone marrow cells was confirmed by the presence of UCP2 protein expression in spleen cell mitochondria of Ucp2+/+ transplanted mice and its absence in Ucp2-/- transplanted mice. Leukocyte counts and plasma cholesterol levels were comparable in both groups. We found a marked increase in atherosclerotic lesion size in the thoracic aorta of Ucp2-/- transplanted mice compared with control Ucp2+/+ transplanted mice (8.3+/-0.9% versus 4.3+/-0.4%, respectively; P<0.005), as well as in the aortic sinus (150 066+/-12 388 microm2 versus 105 689+/-9 727 microm2, respectively; P<0.05). This was associated with increased nitrotyrosine staining, which suggests enhanced oxidative stress. Analysis of plaque composition revealed a significant increase in macrophage accumulation (P<0.05) and apoptosis (P<0.05), along with a decrease in collagen content (P<0.05), suggesting a potentially more vulnerable phenotype. CONCLUSION: These results suggest a protective role for UCP2 against atherosclerosis.

Animals↗
PubMed2003

The atheroprotective effect of 17 beta-estradiol is not altered in P-selectin- or ICAM-1-deficient hypercholesterolemic mice.

The mechanisms that mediate the atheroprotective properties of estrogens remain obscure. In the present study, we evaluated the involvement of the adhesion molecule P-selectin, intercellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1) in the atheroprotective effect of estrogens in murine models evaluating early steps of atherosclerosis. First, we studied the effect of 17 beta-estradiol (E2) administration for 12 weeks on fatty streak constitution at the root aorta of ovariectomized female mice deficient in apolipoprotein E (apoE) alone or deficient in both apoE and either P-selectin or ICAM-1. Compared with respective placebo groups, E2 significantly prevented the development of fatty streak, to a similar extent in all three genotypes (-70.0% in apoE(-/-), -77.4% in apoE(-/-) P-selectin(-/-), and -77.1% in apoE(-/-) ICAM-1(-/-)). Second, the endothelial expression of VCAM-1 at the root aorta was assessed by immunohistochemistry in either placebo or E2-treated ovariectomized C57BL/6 female mice fed an atherogenic diet. Compared with placebo, E2 treatment resulted in a 31.8% decrease of VCAM-1 endothelial expression at this lesion-prone site (P=0.03). These results demonstrate that P-selectin and ICAM-1 are not involved in the atheroprotective effect of estrogens, and suggest that VCAM-1 could play a role in this process.

Animals↗
PubMed2002

Eating frequency and body fatness in middle-aged men.

OBJECTIVE: The relationship between eating frequency and body fatness was tested in a population sample. DESIGN: A cross-sectional survey on cardiovascular risk factors and a nutritional survey were carried out from June 1996 to April 1997. SUBJECTS: Population sample of 330 free-living middle-aged men (45-64 y). MEASUREMENTS: Body mass index (BMI), waist-to-hip ratio (WHR) and nutritional survey (3-day record). RESULTS: In the whole sample, BMI and WHR decreased significantly (P<0.05) along with the increase of the number of eating occasions. When low energy records were excluded, the trend for BMI and WHR according to eating categories remained significant. For WHR, averages were 0.98, 0.95, 0.94 and 0.93 for 1-2, 3, 4 or 5 or more feedings a day, respectively. For BMI, mean values were 28.1, 26.2, 26.2 and 24.5 kg/m(2), respectively. After adjustment for confounders (total energy intake or macronutrients, age, educational level, smoking habits, physical activity and restrained diet), the linear trend for BMI and WHR throughout feeding categories was significant when the whole sample was considered. This relationship remained similar when low energy records or when dieters were excluded. CONCLUSION: These results suggest that for an isoenergetic intake the increase of eating frequency is associated with lower body fatness.

Adipose Tissue↗
PubMed2002

Intensified treatment of type 1 diabetes: prospective evaluation at one year of a therapeutic patient education programme.

BACKGROUND: Type 1 diabetes treatment requires not only an intensive insulin regimen, but also intensive management, which daily involves participation of the patient. Our aim was to prospectively evaluate the efficacy on patient skills and metabolic control of our routine 5-day in-patient education programme. METHODS: Over one year, each type 1 diabetic patient undertaking the programme for the first time, and able to complete a 2, 6, and 12 month follow-up, participated in the study (n=76). At baseline (T0), 61 patients had intensified insulin treatment and 15 increased from 2 to 3 daily insulin injections during the hospital stay. Using questionnaires and analysis of a glycaemia logbook, we evaluated at T0, T2, T6 and T12 patient skills related to diet, physical exercise, self-monitoring of blood glucose (SMBG), adjustment of insulin doses, and treatment of hypoglycaemia. Metabolic control was evaluated at the same time. RESULTS: At one year, the following skills improved: Intake of carbohydrates (T0: 59%, T12: 90% of patients, p<0.001) and snacks (p<0.001), appropriate physical exercise (p<0.001), frequency of SMBG (T0: 3.3 +/- 1.5/day, T12: 4.5 +/- 1/day, p<0.001), frequency of post-prandial tests (p<0.001) and adjustment of insulin doses (T0: 18%, T12: 53% of patients, p<0.001). More patients always carried sugar (T0: 61%, T12: 97%, p<0.001) and appropriately treated hypoglycaemia (T0: 48%, T12: 79%, p<0.001). Concurrently, HbA(1c) decreased (T0: 8.6 +/- 1.5%, T12: 7.7 +/- 0.9%, p<0.001), and the frequency of hypoglycaemia was reduced (p<0.001). There was a correlation between the decrease of HbA(1c) and the frequency of SMBG (p<0.001, r2=0,24). CONCLUSIONS: Education led to positive changes in patient skills, which were maintained over one year and were associated with improved metabolic control.

Blood Glucose↗
PubMed2001

Omapatrilat, a dual angiotensin-converting enzyme and neutral endopeptidase inhibitor, prevents fatty streak deposit in apolipoprotein E-deficient mice.

Angiotensin-converting enzyme (ACE) is mainly responsible for converting angiotensin I (AI) to angiotensin II (AII), and ACE inhibitors prevent atherosclerosis in animal models. Neutral endopeptidase 24.11 (NEP) degrades substance P, kinins and atrial natriuretic peptide (ANP), and aortic wall NEP activity was found to be increased in atherosclerosis. In the present study, we have evaluated the effect of candoxatril, a NEP inhibitor, and of omapatrilat, a dual ACE and NEP inhibitor, on the development of fatty streak in apolipoprotein E (apoE)-deficient mice. Groups of ten male apoE-deficient mice were given either placebo, candoxatril 50 mg/kg per day, or omapatrilat 10, or 100 mg/kg per day for 4 months. None of the treatments influenced body weight, serum total or HDL-cholesterol. Compared with the placebo, candoxatril did not protect the mice from fatty streak deposit. In contrast, omapatrilat dose dependently inhibited the constitution of fatty streak in apoE-deficient mice. The precise advantages of the dual ACE and NEP inhibition versus the inhibition of only ACE should now be considered in the prevention of atherosclerosis as well as in the occurrence of its complications.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

Prevalence of type 2 diabetes and impaired fasting glucose in the middle-aged population of three French regions - The MONICA study 1995-97.

OBJECTIVES: The aim of this study was to determine the prevalence of type 2 diabetes and impaired fasting glucose (IFG) in a population-based sample of 3 508 subjects, aged 35-64 years, participating in the French MONICA population survey from 1995 to 1997 in three French regions: the Urban Community of Lille, the Bas-Rhin and the Haute-Garonne. MATERIAL AND METHODS: Previously diagnosed type 2 diabetes is defined by the current use of oral hypoglycaemic treatment and newly diagnosed subjects by fasting plasma glucose (FPG) > or =7.0 mmol/L according to the ADA 1997 recommendations. IFG was determined by 6.1< or =FPG< or =6.9 mmol/L. Adjusted prevalences are calculated according to the French 1990 census data. RESULTS: Type 2 diabetes adjusted prevalence is 5.1% [4.1-6.1] in women and 7.3% [6.1-8.4] in men while IFG adjusted prevalence is 5.2% [4.2-6.2] and 11.8% [10.3-13.4] respectively. Prevalences of type 2 diabetes and IFG are both significantly higher in men than in women. This trend appears in any age group for IFG, but is only observed in 55-64 year-old subjects for type 2 diabetes. The reduction of the FPG threshold to screen diabetes mellitus from 7.8 to 7.0 mmol/L according to the ADA recommendations results in a 2.2-fold increase in the number of newly diagnosed diabetic subjects, screened by one FPG measurement, in our population-based sample. CONCLUSIONS: The MONICA population survey confirms that type 2 diabetes represents a major health care problem in France and underlines the influence of gender on the prevalence of both type 2 diabetes and IFG in the French middle-aged population.

Adult↗
PubMedDate not supplied

Failure of L-nitroarginine to inhibit the activity of aortic inducible nitric oxide synthase.

Nitric oxide (NO) is produced by a family of three isoenzymes: the endothelial, inducible and neuronal NO synthases. L-Nitroarginine methyl ester (L-NAME) is the most commonly used inhibitor of NO synthase activity. The goal of the present study was to evaluate to what extent L-nitroarginine (L-NA), the in vivo circulating metabolite of L-NAME, blocks NO production in the rat aorta depending on the NO synthase isoform expressed (and evidenced by Western blotting) and on the presence or absence of the extracellular NO synthase substrate L-arginine (100 microM, i.e. the plasma concentration). Intact [endothelium present (E+)] control aortic rings express mainly endothelial NO synthase. L-NA (30--100 microM) induced a dose-dependent contraction (due to blockade of the relaxant properties of NO) irrespective of the presence or absence of L-arginine. In deendothelialized (E-) control aortic rings, the three isoforms of NO synthase are virtually absent (as demonstrated by Western blotting) and L-NA does not elicit any contractile effect. E- aortic rings from lipopolysaccharide (LPS)-treated rats express mainly inducible NO synthase. In these rings, L-NA induced a dose-dependent (0--100 microM) contraction in the absence of extracellular L-arginine, whereas L-arginine (100 microM) completely abrogated the contractile effect of the NO synthase inhibitor. Chronic L-NAME administration (50 mg/kg/day for 4 weeks) elicited the aortic expression of inducible NO synthase, but to a lesser extent (about 5-fold) than in LPS-treated rat aorta. The average plasma concentration of L-NA was 50 +/- 10 microM in these rats. In E- rings from these L-NAME-treated rats, L-NA induced a similar contractile response (but smaller in magnitude) to that observed in LPS-treated rat aorta. Altogether, these data suggest that (1) in the presence of a physiological concentration of extracellular L-arginine, L-NA fails to inhibit inducible NO synthase, and (2) chronic L-NAME administration, at a dose commonly given to block NO production in vivo, leaves the activity of inducible NO synthase unaffected.

Animals↗
PubMedDate not supplied

[Biological factors of post-traumatic stress: neuroendocrine aspects].

The core symptoms of post-traumatic stress disorder (PTSD) include persistent reexperiencing of the traumatic event, avoidance of stimuli associated with the trauma, and autonomic hyperarousal. Many neurotransmitter systems and neurobiologic mechanisms may account for these primary symptoms of PTSD. Severe psychological trauma results in the parallel activation of these systems, producing an array of adaptive behavioral and physiologic responses necessary for survival. The pathophysiology of PTSD may involve dysfunction of several brain structures, particularly the amygdala, locus coeruleus, and hippocampus, as well as noradrenergic system and hypothalamic-pituitary-adrenal (HPA) axis. The neuroendocrinology of PTSD, and specifically hypothalamic-pituitary-adrenal axis alterations, are ways of examining biologic heterogeneity following trauma and its possible clinical implications. The decreased levels of cortisol, the increased responsiveness of glucocorticoid receptors, the increased sensitivity of the HPA negative feedback inhibition and its progressive sensitization are the neuroendocrine alterations specifically associated with the development of PTSD.

Arousal↗