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International audience; Sarcopenia, the age-related loss of skeletal muscle mass, is associated with lipid accumulation and anabolic resistance; phenomena also observed in obesity and worsen when obesity and aging are combined. The endocannabinoid system (ECS) is overactivated in obesity, but its role in aging obesity-related muscle dysfunction is unknown. The aims of this study were to evaluate the effect of inhibition of the ECS by rimonabant (RIM) on the metabolic alterations induced by a high-fat high-sucrose diet and on skeletal muscle mass/function in aged mice. Eighteen-month-old male mice were subjected to a control (CTL) or a high-fat high-sucrose (HFHS) diet for 24 weeks. Mice were administered with saline or RIM (10 mg/kg/day) for the last 4 weeks of the diet. Skeletal muscle function was evaluated by open-field, rotarod, and grip strength tests. Metabolic alterations in liver, adipose tissue, and skeletal muscle were investigated by quantitative RT-PCR. Body mass was higher in HFHS mice compared to CTL mice (48.0 ± 1.5 vs. 33.5 ± 0.7 g, P < 0.01), as a result of fat accumulation (34.8 ± 1.0 vs. 16.7 ± 0.8%, P < 0.01). RIM reduced body fat mass in both CTL (À16%, P < 0.05) and HFHS conditions (À40%, P < 0.01), without affecting hindlimb skeletal muscle mass. In HFHS mice, grip strength evolution was improved (À0.29 ± 0.06 vs. À0.49 ± 0.06 g/g lean mass, P < 0.05), and rotarod activity was increased by %60% in response to RIM (45.9 ± 6.3 vs. 28.5 ± 4.6 cm, P < 0.05). Lipolysis and b-oxidation genes were upregulated in the liver as well as genes involved in adipose tissue browning. These results demonstrate that inhibition of the ECS induces metabolic changes in liver and adipose tissue associated with a reversion of the obese phenotype and that RIM is able to improve motor coordination and muscle strength in aged mice, without affecting skeletal muscle mass. NEW & NOTEWORTHY In 24-month-old mice submitted to high-fat high-sucrose-induced obesity, inhibition of the endocannabinoid system by rimonabant reversed the obese phenotype by promoting adipose tissue browning and b-oxidation in the liver but not in skeletal muscle. These metabolism modifications are associated with improved skeletal muscle function.

Background: The adipose tissue (AT) is a secretory organ producing a wide variety of factors that participate in the genesis of metabolic disorders linked to excess fat mass. Weight loss improves obesity-related disorders.Objectives: Transcriptomic studies on human AT, and a combination of analyses of transcriptome and proteome profiling of conditioned media from adipocytes and stromal cells isolated from human AT, have led to the identification of apolipoprotein M (apoM) as a putative adipokine. We aimed to validate apoM as novel adipokine, investigate the relation of AT APOM expression with metabolic syndrome and insulin sensitivity, and study the regulation of its expression in AT and secretion during calorie restriction-induced weight loss.Methods: We examined APOM mRNA level and secretion in AT from 485 individuals enrolled in 5 independent clinical trials, and in vitro in human multipotent adipose-derived stem cell adipocytes. APOM expression and secretion were measured during dieting.Results: APOM was expressed in human subcutaneous and visceral AT, mainly by adipocytes. ApoM was released into circulation from AT, and plasma apoM concentrations correlate with AT APOM mRNA levels. In AT, APOM expression inversely correlated with adipocyte size, was lower in obese compared to lean individuals, and reduced in subjects with metabolic syndrome and type 2 diabetes. Regardless of fat depot, there was a positive relation between AT APOM expression and systemic insulin sensitivity, independently of fat mass and plasma HDL cholesterol. In human multipotent adipose-derived stem cell adipocytes, APOM expression was enhanced by insulin-sensitizing peroxisome proliferator-activated receptor agonists and inhibited by tumor necrosis factor a, a cytokine that causes insulin resistance. In obese individuals, calorie restriction increased AT APOM expression and secretion.Conclusions: ApoM is a novel adipokine, the expression of which is a hallmark of healthy AT and is upregulated by calorie restriction. AT apoM deserves further investigation as a potential biomarker of risk for diabetes and cardiovascular diseases.

International audience; The number of older obese adults is increasing worldwide. Whether obese adults show similar health benefits in response to lifestyle interventions at different ages is unknown. The study enrolled 25 obese men (body mass index: 31-39 kg/m2) in two arms according to age (30-40 and 60-70 yr old). Participants underwent an 8-wk intervention with moderate calorie restriction (∼20% below individual energy requirements) and supervised endurance training resulting in ∼5% weight loss. Body composition was measured using dual energy X-ray absorptiometry. Insulin sensitivity was assessed during a hypersinsulinemic-euglycemic clamp. Cardiometabolic profile was derived from blood parameters. Subcutaneous fat and vastus lateralis muscle biopsies were used for ex vivo analyses. Two-way repeated-measure ANOVA and linear mixed models were used to evaluate the response to lifestyle intervention and comparison between the two groups. Fat mass was decreased and bone mass was preserved in the two groups after intervention. Muscle mass decreased significantly in older obese men. Cardiovascular risk (Framingham risk score, plasma triglyceride, and cholesterol) and insulin sensitivity were greatly improved to a similar extent in the two age groups after intervention. Changes in adipose tissue and skeletal muscle transcriptomes were marginal. Analysis of the differential response to the lifestyle intervention showed tenuous differences between age groups. These data suggest that lifestyle intervention combining calorie restriction and exercise shows similar beneficial effects on cardiometabolic risk and insulin sensitivity in younger and older obese men. However, attention must be paid to potential loss of muscle mass in response to weight loss in older obese men.NEW & NOTEWORTHY Rise in obesity and aging worldwide are major trends of critical importance in public health. This study addresses a current challenge in obesity management. Do older obese adults respond differently to a lifestyle intervention composed of moderate calorie restriction and supervised physical activity than younger ones? The main conclusion of the study is that older and younger obese men similarly benefit from the intervention in terms of cardiometabolic risk.

Physical activity (PA) demonstrated benefits on brain health, but its relationship with blood biomarkers of neurodegeneration remains poorly investigated. We explored the cross-sectional associations of PA with blood concentrations of neurofilament light chain (NFL) and beta amyloid (Aβ)42/40. We further examined whether the interaction between PA and these biomarkers was longitudinally related to cognition. Four-hundred and sixty-five nondemented older adults engaged in an interventional study and who had a concomitant assessment of PA levels and blood measurements of NFL (pg/mL) and Aβ 42/40 were analyzed. A composite Z-score combining 4 cognitive tests was used for cognitive assessment up to a 4-year follow-up. Multiple linear regressions demonstrated that people achieving 500–999 and 2000+ MET-min/week of PA had lower (ln)NFL concentrations than their inactive peers. Logistic regressions revealed that achieving at least 90 MET-min/week of PA was associated with a lower probability of having high NFL concentrations (ie, ≥91.961 pg/mL [third quartile]). PA was not associated with (Aβ)42/40. Mixed-model linear regressions demonstrated that the reverse relationship between PA and cognitive decline tended to be more pronounced as Aβ 42/40 increased, while it was dampened with increasing levels of (ln)NFL concentrations. This study demonstrates that PA is associated with blood NFL but not with Aβ 42/40. Furthermore, it suggests that PA may attenuate the negative association between amyloid load and cognition, while having high NFL levels mitigates the favorable relationship between PA and cognition. More investigations on non demented older adults are required for further validation of the present findings.

Haemorrhagic radiation cystitis (HRC) is a late complication of pelvic radiotherapy. Severe cases are difficult to treat due to persistent or recurrent bleeding, despite urological and hyperbaric oxygen therapy (HBOT). However, wound healing requires a good nutritional status. In this respect, we aimed at analysing the nutritional status of patients with HRC prior to the onset of HBOT and at highlighting predictive nutritional factors of outcome.Data were retrospectively collected from a cohort of 179 patients with HRC (between 2011 and 2015). Haematuria was graded according to the Subjective, Objective, Management, Analytic scale (SOMA): grade-4 (n = 46) was compared with grade-3 (n = 56), and with grades 1 and 2 (n = 77). S-albumin, prealbumin, vitamins C, D and B6, zinc, selenium, and essential fatty acids were evaluated before HBOT. HBOT response was measured at 3 months according to the haematuria SOMA grade. The Mann-Whitney test, Fisher's exact test and principal-component analysis were used to compare groups.Patients with higher haematuria grades (3 and 4) harboured significant deficiencies in S-albumin, prealbumin, vitamins C, D and B6, zinc, selenium and essential fatty acids. Moreover, grade-4 patients without improvement after 3 months of HBOT had significant lower initial levels of S-albumin, vitamin C, selenium and linoleic acid. Vitamin C levels2.5 mg/L were strongly associated with HBOT non-response (OR 23.14, 95% CI 3.73-143.69, p = 0.002).Our analyses show serious nutritional deficiencies associated with higher grades of HRC and worse prognoses. Patients with haemorrhagic cystitis might benefit from an adequate dietary supplementation to support healing of their bladder mucosa.

International audience; We hypothesized that skeletal muscle contraction produces a cellular stress signal, triggering adipose tissue lipolysis to sustain fuel availability during exercise. The present study aimed at identifying exercise-regulated myokines, also known as exerkines, able to promote lipolysis. Human primary myotubes from lean healthy volunteers were submitted to electrical pulse stimulation (EPS) to mimic either acute intense or chronic moderate exercise. Conditioned media (CM) experiments with human adipocytes were performed. CM and human plasma samples were analyzed using unbiased proteomic screening and/or ELISA. Real-time qPCR was performed in cultured myotubes and muscle biopsy samples. CM from both acute intense and chronic moderate exercise increased basal lipolysis in human adipocytes. Growth and differentiation factor 15 (GDF15) gene expression and secretion increased rapidly upon skeletal muscle contraction. GDF15 protein was upregulated in CM from both acute and chronic exercise–stimulated myotubes. We further showed that physiological concentrations of recombinant GDF15 protein increased lipolysis in human adipose tissue, while blocking GDF15 with a neutralizing antibody abrogated EPS CM-mediated lipolysis. We herein provide the first evidence to our knowledge that GDF15 is a potentially novel exerkine produced by skeletal muscle contraction and able to target human adipose tissue to promote lipolysis.

Purpose of review To focus on state-of-the-art knowledge on the apolipoprotein M (ApoM) physiology and physiopathology regarding metabolism. Recent findings In humans, the ApoM was recently described as secreted by adipocytes. Obesity, metabolic syndrome and type 2 diabetes are associated with low circulating ApoM and adipose tissue APOM expression. Dieting-induced weight loss enhances adipose tissue expression and secretion, and exercise training increases plasma ApoM. The ApoM is a chaperone for the bioactive sphingolipid, sphingosine-1-phosphate (S1P), which has a specific role in inflammation. Its association with S1P in the inhibition of brown adipose tissue activity and subsequent insulin sensitivity was reported with the model of ApoM-deficient mouse. Summary The adipose tissue is an endocrine organ responsible for obesity-related comorbidities. Obesity and dieting impact the adipose tissue secretory profile. The recent demonstration of ApoM being secreted by healthy adipocytes questions about the possible role of this adipose production in metabolic diseases. Low-circulating ApoM is associated with unhealthy metabolic phenotype. The lower circulating apoM during metabolic syndrome might be a cause of obesity-related comorbidities. Lifestyle interventions enhance ApoM production. Whether it acts in combination to S1P or other small lipidic molecules deserves further investigations.

International audience; BACKGROUND: Cross-sectional associations have been found between frail individuals and worse white matter (WM) integrity. However, the prospective association between WM integrity and frailty is still unclear. Our objectives were to measure associations between WM integrity using diffusion tensor imaging (DTI) and the 5-year worsening of frailty in community-dwelling older adults. DESIGN: Secondary analysis of the randomized controlled Multidomain Alzheimer Preventive Trial (MAPT). SETTING: Thirteen memory centers in France and Monaco between 2008 and 2011. PARTICIPANTS: Participants (mean age = 74.7 ± 3.9 years) with no dementia at baseline who had functional magnetic resonance imaging performed as part of the MAPT study (n = 227). MEASUREMENTS: Fractional anisotropy and mean diffusivity (MD), axial diffusivity (AxD), and radial diffusivity (RD) were acquired for 10 different brain regions. Frailty was assessed by the Fried frailty phenotype (score from 0 to 5, higher is worse) at up to seven time points for 5 years. Mixed effect ordinal logistic regression model was used to assess the prospective association between DTI parameters (independent variables) and frailty (dependent variable). All the analyses were adjusted for age, sex, baseline total intracranial volume, and the presence of one of the following cardiovascular risk factors (hypertension, diabetes, and/or hypercholesterolemia). RESULTS: A statistically significant association was found between the RD, AxD, and MD for different brain regions (anterior limb of internal capsule, external capsule, posterior corona radiata, posterior thalamic radiation, superior corona radiata, superior frontal occipital fasciculus, and superior longitudinal fasciculus) and worsening of frailty over 5 years after adjusting for multiple comparisons. CONCLUSIONS: This is the first study to show that WM integrity is associated with frailty in older adults. The mechanisms related to these results require further investigation. J Am Geriatr Soc 68:1050-1055, 2020.

International audience; An efficient regiospecific total synthesis of several branched fatty acyl hydroxyl-fatty acids (FAHFA) has been achieved from available terminal alkenes and alkynes. The key steps feature a boron trifluoride mediated epoxide ring opening with acetylide carbanions, followed by hydrogenation of the alkyne function. The carboxylic acid of the hydroxylated chains is introduced at the last step of the synthesis to allow the esterification of the branched hydroxyl group by fatty acids beforehand. The chemical syntheses of a “linear” FAHFA and a branched FAHFA analog containing a Z-olefin in the hydroxyl-fatty acid chain are also reported. A LC-MS/MS method has been developed. Several reversed phase columns were compared. Regioisomers were separated.

Activation of macrophages by fatty acids (FAs) is a potential mechanism linking obesity to adipose tissue (AT) inflammation and insulin resistance. Here, we investigated the effects of FAs released during adipocyte lipolysis on AT macrophages (ATMs).Human THP-1 macrophages were treated with media from human multipotent adipose-derived stem (hMADS) adipocytes stimulated with lipolytic drugs. Macrophages were also treated with mixtures of FAs and an inhibitor of Toll-like receptor 4, since this receptor is activated by saturated FAs. Levels of mRNA and the secretion of inflammation-related molecules were measured in macrophages. FA composition was determined in adipocytes, conditioned media and macrophages. The effect of chronic inhibition or acute activation of fat cell lipolysis on ATM response was investigated in vivo in mice.Whereas palmitic acid alone activates THP-1, conditioned media from hMADS adipocyte lipolysis had no effect on IL, chemokine and cytokine gene expression, and secretion by macrophages. Mixtures of FAs representing de novo lipogenesis or habitual dietary conditions also had no effect. FAs derived from adipocyte lipolysis were taken up by macrophages and stored as triacylglycerol droplets. In vivo, chronic treatment with an antilipolytic drug did not modify gene expression and number of ATMs in mice with intact or defective Tlr4. Stimulation of adipocyte lipolysis increased storage of neutral lipids by macrophages without change in number and phenotype.Our data suggest that adipocyte lipolysis does not activate inflammatory pathways in ATMs, which instead may act as scavengers of FAs.

Introduction et but de l’etude Les cystites postradiques hemorragiques sont une complication tardive des radiotherapies pelviennes. Le traitement par oxygenotherapie hyperbare est recommande pour ameliorer le pronostic fonctionnel et vital car il favorise la cicatrisation de la muqueuse vesicale. Un statut nutritionnel altere peut contribuer a un retard de cicatrisation. Le statut nutritionnel avant oxygenotherapie hyperbare est decrit en fonction de la gravite initiale de l’hemorragie. Un lien entre les anomalies nutritionnelles et la reponse clinique a l’oxygenotherapie hyperbare est recherche. Materiel et methodes L’etude observationnelle et retrospective a inclus 179 patients atteints de cystite radique isolee, lors de la consultation d’indication d’oxygenotherapie hyperbare dans le centre universitaire de medecine hyperbare de Toulouse de 2011 a 2015. Leur cystite a ete classee selon le score SOMA (Subjective Objective Management Analytical), 77 patients avaient un grade 1 ou 2 (hematurie sans anemie), 56 un grade 3 (hematurie entrainant une anemie moderee) et 46 un grade 4 (anemie necessitant une transfusion). Les patients n’avaient pas de pathologie susceptible d’entrainer une malabsorption intestinale. A l’inclusion, l’albumine, la vitamine C, la 25OH-vitamine D, le pyridoxal phosphate (vitamine B6), le zinc, le selenium, et les acides gras essentiels des phospholipides plasmatiques ont ete doses. Le devenir des patients a ete evalue cliniquement a 3 mois, apres la fin du traitement par oxygenotherapie hyperbare (40 a 60 seances). Les comparaisons intergroupes ont utilise un test Mann-Whitney. L’ACP et le test du X2 ont permis d’argumenter les niveaux des seuils pronostics des parametres biologiques etudies. Resultats Les patients (92 % d’hommes) avaient en moyenne 74 ans. Les cystites de grades 3 et surtout 4 etaient associes a des carences nutritionnelles en albumine, vitamines C, D et B6, zinc, selenium, et acides gras essentiels. Vingt-quatre pour cent des patients avec cystites de grade 4 avaient une denutrition proteoenergetique severe. Quatre-vingt-sept pour cent des patients atteints de cystites de grades 4 avaient des valeurs de vitamine C inferieures au seuil optimal de 10 mg/L et 20 % etaient en dessous du seuil scorbutique (2,5 mg/L). Par ailleurs, les patients atteints de cystite de grade 4 les plus refractaires a l’efficacite du traitement par oxygenotherapie hyperbare avaient des concentrations initiales significativement plus basses en albumine, vitamine C, et selenium par rapport a ceux dont l’evolution etait favorable : les valeurs predictives positives (VPP) et negatives (VPN) etaient respectivement de 60 et 77 % pour une concentration d’albumine inferieure a 30 g/L, 86 et 79 % pour une concentration en vitamine C inferieure a 2,5 mg/L et 83 et 79 % pour une concentration de selenium inferieure a 0,65 μmol/L. Conclusion Cette etude montre l’existence de carences nutritionnelles importantes chez les patients atteints de cystite radique, en particulier de grade severe. En outre, certaines carences sont associees a un pronostic defavorable de la maladie et ce, meme apres oxygenotherapie hyperbare. L’evaluation du statut nutritionnel et son optimisation chez ces patients est cruciale pour favoriser la cicatrisation du tissu vesical ; d’apres les observations recueillies grâce a ce travail, elle pourrait s’averer indispensable dans la prise en charge precoce de ces patients.

Besides adipocytes, specialized in lipid handling and involved in energy balance regulation, white adipose tissue (WAT) is mainly composed of other cell types among which lymphocytes represent a non-negligible proportion. Different types of lymphocytes (B, alphabetaT, gammadeltaT, NK and NKT) have been detected in WAT of rodents or humans, and vary in their relative proportion according to the fat pad anatomical location. The lymphocytes found in intra-abdominal, visceral fat pads seem representative of innate immunity, while those present in subcutaneous fat depots are part of adaptive immunity, at least in mice. Both the number and the activity of the different lymphocyte classes, except B lymphocytes, are modified in obesity. Several of these modifications in the relative proportions of the lymphocyte classes depend on the degree of obesity, or on leptin concentration, or even fat depot anatomical location. Recent studies suggest that alterations of lymphocyte number and composition precede the macrophage increase and the enhanced inflammatory state of WAT found in obesity. Lymphocytes express receptors to adipokines while several proinflammatory chemokines are produced in WAT, rendering intricate crosstalk between fat and immune cells. However, the evidences and controversies available so far are in favour of an involvement of lymphocytes in the control of the number of other cells in WAT, either adipocytes or immune cells and of their secretory and metabolic activities. Therefore, immunotherapy deserves to be considered as a promising approach to treat the endocrino-metabolic disorders associated to excessive fat mass development.

Le tissu adipeux est constitue a 60 % de types cellulaires autres que les adipocytes. Parmi ces cellules, il a ete recemment montre que la population lymphocytaire represente une fraction non negligeable chez l’animal comme chez l’homme. Bien que les proportions des differentes classes de lymphocytes presents au sein du tissu adipeux varient en fonction de l’espece et du depot considere, toutes sont representees (lymphocytes B, T, NK et NKT). La proportion des lymphocytes dans les depots adipeux varie au cours de l’obesite a l’exception de celle des lymphocytes B. Ces variations sont fonction du degre de developpement du tissu adipeux, de la leptine et/ou de la presence d’une inflammation au sein du tissu. Les roles de ces differentes populations lymphocytaires sont encore mal compris. Neanmoins, les donnees actuelles permettent de proposer leur implication dans le controle : 1) du nombre de cellules via leur action cytotoxique ou trophique ; 2) des activites secretoires et metaboliques des cellules du tissu adipeux. Toutes ces fonctions permettent d’ouvrir de nouveaux champs de recherche dans la comprehension du developpement des desordres metaboliques, inflammatoires et immunitaires associes a l’obesite.

Despite well-established variations in the health risks posed by visceral vs. subcutaneous abdominal (SCABD) fat depots, surprisingly little is known on the differences within a given adipose tissue (AT) among severely obese patients displaying varying metabolic dysfunction. We thus compared, by quantitative PCR, the expression profile of a number of genes in the SCABD, omental (OME), and mesenteric (MES) depots of severely obese women with (DYS; n = 25) or without (NDYS; n = 23) a dysmetabolic profile. Fasting insulinemia and HOmeostasis Model Assessment-insulin resistance (HOMA-IR) were higher and plasma adiponectin level lower in DYS women (p

Ancestral lymphoid cells reside in adipose tissues, and their numbers are highly altered in obesity. Leptin, production of which is correlated to fat mass, is strongly involved in the relationships between adipose tissues and immune system. We investigated in epididymal (EPI) and inguinal (ING) fat pads to determine whether 1) lymphocyte phenotypes were correlated to the tissue weight and 2) leptin was involved in such relationships. Immunohistological analyses revealed a tight relationship between the T and NK lymphocytes of the stromal vascular fraction and adipocytes. We identified a significant negative and positive correlation between EPI weight and the percentage of NK and total T cells respectively by cytofluorometric analyses. The NK and ancestral gammadelta T cell contents were directly dependent of leptin since they increased significantly in high-fat (HF) diet mice but not in leptin-deficient (ob/ob) mice as compared to control. By contrast, the alphabeta T cell content seemed independent of leptin because their percentages increased significantly with the EPI weight whatever the type of mice (control, HF, ob/ob). The present study suggests that adipose tissues present, according to their localization, different immunological mechanisms that might be involved in the regulation of adipose cells functions and proliferations.

Le tissu adipeux est l'un des tissus les plus abondants du corps humain. Le tissu adipeux blanc est compose de deux populations cellulaires qui peuvent etre separees facilement, les adipocytes matures d'une part et, d'autre part, la fraction stroma-vasculaire (SVF). Celle-ci contient deux compartiments, l'un stromal et l'autre hematopoietique, qui ont ete recemment caracterises. La population stromale (ou ADAS) presente des analogies fonctionnelles ainsi qu'une relation de lignage avec les macrophages. Ces cellules qui peuvent egalement se differencier en adipocytes ou en cellules endotheliales peuvent etre considerees comme des progeniteurs vasculaires. Il a egalement ete montre que certaines cellules presentes dans le tissu adipeux pouvaient se differencier in vitro ou in vivo en osteoblastes, chondrocytes, cardiomyocytes, cellules musculaires, hematopoietiques ou neuronales. Le tissu adipeux apparait donc comme un tissu complexe compose de cellules dont la nature et les potentiels de differenciation varient en fonction de leur localisation ou de l'environnement physiologique ou pathologique, et ces differentes sous populations peuvent interagir entre elles par le biais de secretions paracrines. Le tissu adipeux est donc un tissu heterogene et plastique, facile a prelever, qui pourrait representer une source potentielle de cellules dont l'utilisation en therapie cellulaire semble prometteuse.

Although it is well accepted that treatment with nucleoside reverse transcriptase inhibitors (NRTIs) modifies fat metabolism and fat distribution in humans, the mechanisms underlying these modifications are not yet known. The present investigation examines the effects of chronic oral administration of 3'-azido-3'-deoxythymidine (AZT) on the mitochondrial metabolism and the redox status management of rat white adipose tissues originating from two anatomical sites, as well as of the rat liver. Results showed that AZT treatment induced differential effects on the mitochondrial functions depending on the anatomical localisation. Indeed, in inguinal adipose tissue, a significant decrease in the cytochrome c oxidase activity and in the mitochondrial DNA (mtDNA) content was observed, whereas the activity of citrate synthase, a mitochondrial protein exclusively encoded by the nucleus, was not affected. In contrast, no significant change in these parameters could be detected for epididymal tissue and for liver. In parallel, no oxidative stress could be detected after treatment, for both white adipose tissues and for liver, even though treated liver exhibited several modifications in redox management. Taken together, these data demonstrate differential mitochondrial effects of AZT on subcutaneous versus visceral white adipose tissue. Moreover, the decrease in mitochondrial oxidative capacity of inguinal adipocyte consecutive to AZT treatment is not primarily due to an oxidative stress per se, but rather to a depletion of the mtDNA content per cell.

Recently, it was demonstrated that CD8(+) T cells are important for the response against Chlamydia pneumoniae. By use of the human monocytic cell line U937 and human monocytes taken from peripheral blood, we investigated the effect of infection on various molecules critical for CD8(+) T cell function. A strong secretion of interleukin (IL)-10 by infected cells was observed, together with an inhibited expression of major histocompatibility complex (MHC) class I antigens, but without significant alteration of tumor growth factor-beta secretion or MHC class II expression. Recombinant IL-10 added to uninfected U937 cells decreased the expression of MHC class I, whereas blocking antibodies to IL-10 and its receptor abolished the C. pneumoniae-induced inhibition of MHC class I expression. Analysis of our data provides evidence that IL-10 secretion induced by C. pneumoniae infection of monocytic cells down-regulates the expression of MHC class I molecules and thereby might reduce the presentation of bacterial epitopes by MHC. This would decrease the ability of CD8(+) T cells to eliminate infected cells.

Activated T-lymphocytes are found early in atherosclerosis lesions, but little is known about their role. Oxidized low-density lipoproteins (oxLDLs) are considered to be involved in the pathogenesis of the lesions, and we have previously demonstrated that oxLDLs inhibit not only interleukin (IL)-2-receptor expression on the surface of in vitro-activated T-lymphocytes but also their proliferation. We have now investigated the effect of oxLDLs on blast differentiation, on IL-2 synthesis and on the activation of the nuclear factor kappaB (NF-kappaB) system in activated lymphocytes. Mildly oxLDLs (50 and 100 microgram/ml) decreased the number of lymphoblasts and the level of IL-2 concentration in the culture supernatants after activation of lymphocytes by phytohaemagglutinin and PMA+ionomycin. The inhibition of IL-2 production was observed in the CD3(+) T-lymphocyte cytoplasm as early as 4 h after activation by PMA+ionomycin. The study of NF-kappaB showed that oxLDLs led to a decrease of activation-induced p65/p50 NF-kappaB heterodimer binding to DNA, whereas the presence of the constitutive nuclear form of p50 dimer was unchanged. This was correlated with an unchanged level of the active form of the cytosolic inhibitor protein IkappaB-alpha. Taken together, these observations suggest that the immunosuppressive effect of oxLDLs might operate via a dysregulation of the T-lymphocyte activation mechanisms.

Activated T-lymphocytes are present in early atherosclerotic lesions where they may interact with oxidized low-density lipoproteins (oxLDLs). In this study the non-specific effect of oxLDLs on the activation of T-cells in v itro was investigated. LDLs were oxidized by UV irradiation and characterized by a low level of lipid peroxidation and only slight apolipoprotein B modification. Peripheral blood lymphocytes from normal individuals were stimulated in v itro with the polyclonal activator phytohaemagglutinin in the presence of various doses of LDLs and oxLDLs. LDLs enhanced the proliferation of peripheral blood lymphocytes at doses up to 100 μ g/ml but were inhibitory at 200 μ g/ml, whereas low doses of oxLDLs (over 10 μ g/ml) inhibited the proliferation. OxLDLs also inhibited the proliferative responses of an alloreactive CD4 + T-cell line immortalized by Herpes virus saimiri and an influenza haemagglutinin-specific CD4 + T-cell clone. Viability tests using Trypan Blue exclusion or expression of Apo2.7, an apoptosis marker, did not indicate any significant cell death at doses up to 100 μ g/ml oxLDL. At this concentration, cell-cycle analysis showed an accumulation of cells at the G 1 /S interface in the CD4 + cell clone, without significant DNA fragmentation. The expression of the activation antigen CD25 on T-lymphocytes (on phytohaemagglutinin-activated T-cells and on CD4 + T-cell clone), requisite to the commitment of activated T-cells from G 1 phase to S phase, was also inhibited by oxLDLs whereas expression of other activation antigens such as CD69 and HLA-DR was unchanged. In conclusion, these data show that mildly oxidized LDLs inhibit the proliferation and CD25 expression of activated T-lymphocytes and suggest that oxLDLs may slow down the T-cell response in atherosclerotic lesions.

In the present paper, it was attempted to define the amino acids or regions on TCR beta molecules that determine the TCR alpha-TCR beta interaction. Sequence studies on HBP-ALL variant cells with an intrinsic deficiency in TCR alpha beta dimer formation elucidated a conserved amino acid motif in the TCR-C beta beta-strand E, = Y(C)(L)(S)SRLR(V)(S)(A); this motif seems to represent one interaction area for the TCR alpha-TCR beta interaction. In addition, amino acids in the connecting peptide may be shaped in a precise structure (by the interactions with CD3 molecules?) involved in TCR alpha-TCR beta dimerization. This result was supported by the finding that the interchain disulfide bond between TCR alpha and beta chains is not required for membrane expression or transmembrane signal transduction of TCR alpha beta-CD3 complexes. Finally, comparative results from two membrane TCR-CD3-negative Jurkat variants R4.9 and E6.E12 suggest that TCR-C beta exon 1- and 2-encoded amino acids are important for the TCR beta-CD3 gamma epsilon association.

Objectives: Oxidative stress is associated with the condition of cystic fibrosis (CF), but no guidelines exist for its assessment or treatment. Our aim was to evaluate a test that measures the blood antioxidant capability in CF children. Methods: This antioxidant capability was assessed by the Kit Radicaux Libres (KRL) test in 44 CF children (24 boys). We recorded also anthropometric measures, pulmonary function, CF severity scores, and plasma nutritional and inflammatory parameters (proteins, vitamins, erythrocyte fatty acids, and micronutrients). We performed univariate and multivariate analyses with linear regression models. Results: The mean age at the first KRL assessment was 12.2 ± 3.8 years. Factors that correlated with decreased antioxidant capacity were mostly related to the severity of pulmonary disease [ forced expiratory volume at 1 second (FEV1), acute exacerbation, and congestion. In multivariate analysis, the correlation between Brasfield score and erythrocyte antioxidant potential remained significant (β = - 0.611, p < 0.001). Among nutritional factors, the ω6/ω3 ratio was significantly correlated to erythrocyte antioxidant potential (β = - 1.213, p = 0.01). Conclusion: The blood antioxidant capability, measured by the KRL test, appears to be an interesting biomarker to evaluate oxidative stress in CF. This study suggests that the ω6/ω3 ratio should be regarded as a nutritional marker in antioxidant management in CF children.

Partial inhibition of adipose tissue lipolysis does not increase fat mass but improves glucose metabolism and insulin sensitivity through modulation of fatty acid turnover and induction of fat cell de novo lipogenesis., When energy is needed, white adipose tissue (WAT) provides fatty acids (FAs) for use in peripheral tissues via stimulation of fat cell lipolysis. FAs have been postulated to play a critical role in the development of obesity-induced insulin resistance, a major risk factor for diabetes and cardiovascular disease. However, whether and how chronic inhibition of fat mobilization from WAT modulates insulin sensitivity remains elusive. Hormone-sensitive lipase (HSL) participates in the breakdown of WAT triacylglycerol into FAs. HSL haploinsufficiency and treatment with a HSL inhibitor resulted in improvement of insulin tolerance without impact on body weight, fat mass, and WAT inflammation in high-fat-diet–fed mice. In vivo palmitate turnover analysis revealed that blunted lipolytic capacity is associated with diminution in FA uptake and storage in peripheral tissues of obese HSL haploinsufficient mice. The reduction in FA turnover was accompanied by an improvement of glucose metabolism with a shift in respiratory quotient, increase of glucose uptake in WAT and skeletal muscle, and enhancement of de novo lipogenesis and insulin signalling in liver. In human adipocytes, HSL gene silencing led to improved insulin-stimulated glucose uptake, resulting in increased de novo lipogenesis and activation of cognate gene expression. In clinical studies, WAT lipolytic rate was positively and negatively correlated with indexes of insulin resistance and WAT de novo lipogenesis gene expression, respectively. In obese individuals, chronic inhibition of lipolysis resulted in induction of WAT de novo lipogenesis gene expression. Thus, reduction in WAT lipolysis reshapes FA fluxes without increase of fat mass and improves glucose metabolism through cell-autonomous induction of fat cell de novo lipogenesis, which contributes to improved insulin sensitivity., Author Summary In periods of energy demand, mobilization of fat stores in mammals (i.e., adipose tissue lipolysis) is essential to provide energy in the form of fatty acids. In excess, however, fatty acids induce resistance to the action of insulin, which serves to regulate glucose metabolism in skeletal muscle and liver. Insulin resistance (or low insulin sensitivity) is believed to be a cornerstone of the complications of obesity such as type 2 diabetes and cardiovascular diseases. In this study, our clinical observation of natural variation in fat cell lipolysis in individuals reveals that a high lipolytic rate is associated with low insulin sensitivity. Furthermore, partial genetic and pharmacologic inhibition of hormone-sensitive lipase, one of the enzymes involved in the breakdown of white adipose tissue lipids, results in improvement of insulin sensitivity in mice without gain in body weight and fat mass. We undertake a series of mechanistic studies in mice and in human fat cells to show that blunted lipolytic capacity increases the synthesis of new fatty acids from glucose in fat cells, a pathway that has recently been shown by others to be a major determinant of whole body insulin sensitivity. In conclusion, partial inhibition of adipose tissue lipolysis is a plausible strategy in the treatment of obesity-related insulin resistance.

International audience; BACKGROUND: Fatty acids (FAs) and adipokines such as adiponectin or interleukin-6 (IL-6) are known to modulate inflammation and the development of metabolic syndrome. Whether FA composition assessed in plasma triacylglycerols (TAGs), phospholipids (PLs) and non-esterified fatty acids (NEFAs) and adipose tissue (AT) PLs differed between dysmetabolic and non-dysmetabolic severely obese women remains to be established. Whether the plasma and/or AT arachidonic acid (AA)/eicosapentaenoic acid (EPA) ratio in the PL sub-fraction may be associated with adipokine AT gene expression needs to be examined. METHODS: FA composition was measured in plasma lipid classes and in the TAG and PL sub-fractions of subcutaneous abdominal and omental ATs of severely obese women paired for age and adiposity but showing a dysmetabolic profile (n = 13) or not (n = 14). FA profile was assessed by gas chromatography. Plasma and AT mRNA concentrations of adiponectin and IL-6 were measured by ELISA and real-time polymerase chain reaction, respectively. RESULTS: Plasma adiponectin and FA concentrations in the NEFA sub-fraction were, respectively, lower and higher in dysmetabolic than in non-dysmetabolic women (p < 0.05). Despite similar FA levels in the PL sub-fraction, the AA/EPA ratio was higher in plasma and ATs (p < 0.005), because of an EPA decrease in plasma and subcutaneous abdominal fat vs. an AA increase in the omental depot. The AA/EPA ratio was negatively associated with adiponectin concentrations in plasma and subcutaneous abdominal AT (0.01 < p < 0.05). CONCLUSIONS: Metabolic dysfunction is associated with a pro-inflammatory phospholipid AA/EPA ratio in plasma and ATs, and an altered adiponectin secretion that could contribute to developing metabolic syndrome.

Summary Background & aims The energy deficit in anorexia nervosa (AN) results from a low energy and fat intake. Data from the literature are at odds about a deficiency in essential fatty acids (EFA), linoleic (LA) and alpha-linolenic (ALA) acid. The aim of the present study was to determine RBC phospholipid FA composition in AN patients, and to relate this FA profile to fat mass and BMI. We postulated that there should not be a deficit in EFA, because AN patients are in negative energy balance, and a significant supply of EFA arises from the lipolysis of AT triglycerides. Methods Twenty-two AN women (14.2 ± 2.0 kg/m2 BMI) had a DEXA-body composition analysis, and an analysis of FA composition in the phospholipids of red blood cell membranes by capillary gas chromatography. The control group was made of 25 healthy women. Results There was no EFA deficiency in RBC, i.e. no decrease in LA and ALA, and no rise in C20:3 n-9. However, long chain poly-unsaturated FA (LC-PUFA), mainly those of the n-3 family were significantly reduced. A negative correlation was found between fat mass and ALA, with a critical fat mass close to 5 kg, under which ALA was dramatically increased. Conclusion AN patients display a complex membrane FA profile without traits of EFA deficiency but with a deficiency in LC-PUFA. We propose that adipose tissue is an endogenous source of FA able to compensate for the reduced food intake in EFA, but unable to provide enough LC-PUFA.

WOS: 000285876900007; International audience; Coenzyme Q (CoQ) is not only the single antioxidant synthesized in humans but also an obligatory element of mitochondrial functions. We have previously reported CoQ deficiency in white adipose tissue of ob/ob mice. We sought to determine (i) whether this deficit exists in all species and its relevance in human obesity and (ii) to what extent CoQ could be involved in adipocyte differentiation. Here we identified in rodents as well as in humans a specific very strong nonlinear negative correlation between CoQ content in subcutaneous adipose tissue and obesity indexes. This striking correlation reveals a threshold value similar in both species. This relative deficit in CoQ content in adipose tissue rapidly took place during the time course of high-fat-diet-induced obesity in mice. Adipocyte differentiation was assessed in vitro using the preadipocyte 3T3-F442A cell line. When CoQ synthesis was inhibited by a pharmacological approach using chlorobenzoic acid, this strongly triggered adipose differentiation. In contrast, adipogenesis was strongly inhibited when a long-term increase in CoQ content was obtained by overexpressing human 4-hydroxy benzoate acid polyprenyltransferase gene. Altogether, these data suggest that a strict level of CoQ remains essential for adipocyte differentiation, and its impairment is associated with obesity.

Introduction et but de l’etude L’exposition a la lumiere et l’environnement a haute teneur en oxygene de la retine, riche en acides gras polyinsatures au niveau des segments externes des photorecepteurs, la predisposent au stress oxydatif qui serait notamment implique dans la degenerescence maculaire liee a l’âge (DMLA). L’objectif de ce travail est d’evaluer le stress oxydant chez les patients atteints de DMLA a l’aide du test biologique KRL® (Kit Radicaux libres, SPIRAL laboratories, Couternon, France). Materiel et methodes Le stress oxydant est evalue chez 33 patients atteints de DMLA et 28 controles admis dans le service d’Ophtalmologie du CHU Toulouse Purpan au moyen d’un test simple, le test KRL®. Ce dernier consiste a soumettre un echantillon sanguin, sang total ou suspension de globules rouges, a une agression radicalaire standardisee La resistance des globules rouges a cette attaque radicalaire est exprimee par le temps de demi-lyse (temps necessaire a l’hemolyse de 50 % des globules rouges) et par le temps de latence (temps necessaire au debut de l’hemolyse). La vitamine C et l’alpha-carotene ont ete doses par Chromatographie Liquide Haute Performance. Resultats et Analyse statistique Les temps de demi-lyse et de latence du sang total des patients (n = 33) sont significativement plus bas que celui des temoins (n = 28), respectivement 77,9 ± 8,8 vs 86,24 ± 9,74 min (p patients par rapport aux temoins, respectivement 5,25 ± 3,73 vs 13,4 ± 2,96mg/l (p= 0,003) et 0,066 ± 0,076 vs 0,128 ± 0,069 mg/l (p Conclusion Cette etude montre que le temps de demi-lyse du sang total mesure par le test KRL et le taux serique de vitamine C sont diminues chez les patients atteints de DMLA et qu’il existe une correlation entre ces deux parametres. Ce test est un bon reflet des alterations du statut en defenses anti-oxydantes circulantes. Ces resultats sont concordants avec la litterature qui rapporte une augmentation du stress oxydant dans la DMLA et l’effet benefique d’une supplementation en antioxydants sur la prevention de complications de la DMLA. Le test KRL, simple a realiser, pourrait permettre d’evaluer rapidement la capacite antioxydante globale de patients atteints de DMLA et de suivre les benefices d’une supplementation en antioxydants.

Introduction et but de l’etude La comprehension des adaptations metaboliques et moleculaires du tissu adipeux (TA) accompagnant une perte de poids est essentielle dans le cadre de la recherche sur la physiopathologie de l’obesite. Dans ce contexte, les omiques, et particulierement la genomique du TA, ont permis d’ameliorer la connaissance de ces adaptations. Une approche innovante est d’integrer les jeux de donnees de plusieurs types de omiques afin d’avoir une vue globale et exhaustive sur les interactions entre chaque variable et de les relier a des evenements cliniques, tels les variations de poids. Le but de ce travail etait d’etudier les relations entre des variables bio-cliniques d’individus obeses, l’expression des genes et le contenu en acides gras (AG) du TA, a chaque etape d’un programme nutritionnel et en relation avec les variations ponderales. Materiel et methodes La determination du contenu en AG du TA sous cutane abdominal et les mesures d’expression de 221 genes ont ete realisees chez 135 femmes obeses de la cohorte europeenne DiOGenes, avant le regime, apres une phase de restriction calorique de 8 semaines et apres 6 mois de suivi ponderal ad libitum. Les individus ont ete stratifies a posteriori en 3 groupes selon les variations de poids apres la restriction. Afin d’etudier les relations entre les 3 jeux de donnees (AG, transcrits, variables bio-cliniques), une analyse de reseau basee sur un modele graphique gaussien a ete utilisee. Au sein de chaque jeu de donnees, les relations entre les variables ont ete etablies par estimation des correlations partielles. Les relations entre les variables de 2 jeux de donnees ont ete etudiees par une analyse de correlations canoniques regularisees. Une approche integrative a permis de fusionner tous les types de relations. Pour faire ressortir la macro-structure des reseaux, une classification de sommets a ete utilisee, permettant de generer des sous-reseaux. Les principaux sommets des sous-reseaux ont ete extraits et leur importance (centrealite) testee statistiquement. La fonction biologique des variables composant ces sous-reseaux reseaux a ete analysee. Resultats et Analyse statistique A la fin de la phase de suivi et dans le groupe de femmes reprenant du poids, 3 sous-reseaux sur 5 montrent des genes impliques dans des voies de croissance, angioge-nese et signalisation de proliferation, suggerant une hyperplasie. Apres la phase de restriction, une relation positive forte entre l’acide myristoleique (un AG peu represente dans le TA et dans l’alimentation) et des genes codant pour les principales enzymes de la lipogenese de novo a ete observee. A la fin de la phase de suivi, dans le groupe de femmes qui ont continue a perdre du poids, cette relation entre acide myristo-leique et genes de la lipogenese de novo est egalement retrouvee. Conclusion Cette approche originale de biologie des systemes apporte un regard nouveau sur la reponse du TA au controle ponderal, en soulignant le role central et inattendu de l’acide myristo-leique, qui pourrait etre un determinant de l’impact metabolique benefique de la perte de poids. La signature specifique du TA des femmes reprenant du poids suggere au contraire une signature hyperplasique defavorable.

T cell antigen receptor (TcR) heterodimers of both the Ti-alpha beta and Ti-gamma delta types are expressed at the surface of T cells noncovalently associated with the CD3 complex composed of the monomorphic chains gamma, delta, epsilon and zeta. The structural relationship and assembly of the various components of this multimeric protein complex is still not fully understood. In this report, the human leukemic T cell line Lyon which expresses a Ti-gamma delta/CD3 complex, was characterized and compared to another human leukemic T cell line Jurkat (Ti-alpha beta/CD3). Membrane TCR-/CD3- variants of the T cell Lyon were induced and found to produce all of the Ti/CD3 components, with the exception of Ti-delta. Biochemical analysis indicated that: (1) Ti-gamma/CD3 gamma, delta, epsilon complexes were formed in the endoplasmic reticulum in the absence of Ti-delta; (2) the CD3-zeta chain did not associate with the Ti-gamma/CD3 gamma delta epsilon complex and (3) the Ti-delta chain was required for cell surface expression of the Ti-gamma delta/CD3 complex. Introduction of Jurkat wild-type Ti-alpha cDNA into Lyon T cells resulted in Ti-alpha beta/CD3 expression and abrogated Ti-gamma delta/CD3 expression. In contrast, the expression of the Ti-gamma delta/CD3 complex was not affected by transfection of a mutated Ti-alpha cDNA into Lyon cells. The mutated Ti-alpha chain formed complexes with Ti-beta and CD3 gamma delta epsilon, but the CD3-zeta chain did not associate with these complexes. Taken together analysis of Lyon cells transfected with either wild-type or mutated Ti-alpha suggested that the CD3-zeta chain may have higher affinity for Ti-alpha beta/CD3 complexes than for Ti-gamma delta/CD3 complexes.

Summary Background The outcome of coronary diseases is influenced by lifestyle and diet. Among dietary factors, n-3 polyunsaturated fatty acids reduce mortality from cardiovascular diseases. Aims To evaluate the impact of dietary and lifestyle advice by calculation of scores and analysis of plasmatic lipids and the fatty acid composition of erythrocyte membrane phospholipids after 1 year of patient education in 66 patients with acute coronary syndromes. Methods The answers given by patients during questioning were transformed into scores (atherosclerosis risk, dietary habits and global scores) at inclusion and after 1 year of follow-up. Classical metabolic risk factors and fatty acid composition of erythrocyte phospholipids were determined at the same time. Results After 1 year of education, patients improved their different scores, particularly by changing dietary habits. The positive impact was seen in the blood lipid and erythrocyte fatty acid levels: plasma low-density lipoprotein cholesterol and triglyceride concentrations were lowered and n-3 polyunsaturated fatty acid percentages were improved in phospholipids. Conclusion Global score, lipid variables and the nature of the polyunsaturated fatty acids in erythrocyte phospholipids help us to evaluate patients with high coronary artery disease risk and the benefits of long-term dietary and lifestyle advice.

1525-2191 (Electronic) Journal Article; Obesity is associated with low-grade inflammation and leukocyte infiltration in white adipose tissue (WAT) and is linked to diabetic complications. Semicarbazide-sensitive amine oxidase, also known as vascular adhesion protein-1 (SSAO/VAP-1), is a membrane protein that is highly expressed in adipocytes and is also present on the endothelial cell surface where it is involved in leukocyte extravasation. We studied fat deposition and leukocyte infiltration in WAT of mice with a null mutation in the amine oxidase copper-containing-3 (AOC3) gene encoding SSAO/VAP-1. Both epididymal and inguinal WATs were larger in 6-month-old AOC3-KO males than in age-matched wild-type controls. However, WAT from AOC3-KO mice contained lower CD45 mRNA levels and fewer CD45(+) leukocytes. Subpopulation analyses revealed a diminished infiltration of WAT by T cells, macrophages, natural killer, and natural killer T cells. A decrease in leukocyte content in WAT was also detected in female AOC3-KO mice as early as 2 months of age, whereas increased fat mass was evident by 6 months of age. Reduced CD45(+) populations in WAT of AOC3-KO mice was not rescued by human SSAO/VAP-1 expression on adipocytes under the control of aP2, suggesting the importance of vascular AOC3 in leukocyte entrance into fat. Our results indicate that SSAO/VAP-1 is instrumental for the presence of leukocytes in WAT. Therefore, AOC3-KO mice present a unique model of mild obesity, characterized by increased WAT devoid of low-grade inflammation.

1873-2933 (Electronic) Journal Article; OBJECTIVES: This work aims to evaluate the resistance of mononuclear cells to oxidative stress using a "KRL" test, formerly utilized to evaluate the resistance of erythrocyte to free radicals. METHODS: The "KRL" test evaluates the resistance to lysis of cells treated by free radicals generated under standardized conditions. RESULTS: We defined new analytical parameters (level of radical production, time course, number of cells) to obtain an accurate assay determining the resistance to oxidative stress of mononuclear cells, in comparison to that of erythrocytes. This test allows the evaluation of change in the redox state of mononuclear cells (improved by an antioxidant mix or deteriorated by antimycin A-induced mitochondrial radical overproduction). Interestingly, our data show that the sensitivity of mononuclear cells to oxidative stress is not correlated with the susceptibility of erythrocytes to oxidative stress. CONCLUSIONS: The quantification of the susceptibility of mononuclear cells to oxidative stress gives additional information (in addition to erythrocyte resistance) and could be helpful for patients with chronic inflammation.

Il a ete suggere que les patients avec un surfactant pulmonaire altere sont plus susceptibles a Pneumocystis que les individus avec un surfactant normal. Comme la plupart des patients avec des alterations du surfactant presentent une hypoxie associee, nous avons explore l'effet de conditions d'hypoxie hypobare intermittente sur la capacite de rats non-immunocompromis infectes avec Pneumocystis carinii par voie endo-tracheale, a eliminer leur infection. Les rats temoins, inocules ou pas avec P. carinii, ont ete maintenus dans des conditions de pression atmospherique et d'oxygenation normales et traites ou pas par la dexamethasone. Ces experiences ont montre que meme si les conditions d'hypoxie hypobare alterent significativement la composition du surfactant, notamment le niveaux de proteines A et D, et affectent les effecteurs de la reponse immune, elles ne facilitent pas la croissance de P. carinii ni inhibent les mecanismes d'elimination des parasites des poumons des rats non-immunocompromis. L'influence potentielle des changements des proteines du surfactant sur l'infection par Pneumocystis, est discutee.

White adipose tissue (WAT) represents a large amount of all adult tissues. For a long time, it was considered as a poorly active, overgrown and undesirable tissue. It was mainly studied for its involvement in energy metabolism and disorders, as well as for its endocrine functions. WAT is composed of two main populations, matures adipocytes and stroma vascular fraction (SVF) that can be separated easily. The SVF contains two compartments, stromal and hematopoietic that have been recently characterized. The stromal population (or ADAS for Adipose Derived Stromal Cells) presents functional features of, as well as lineage relationship with, macrophages. These stromal cells, that are able to differentiate into adipocytes, also display endothelial potential, and could be considered as vascular progenitors. Differentiation of various adipose-derived cell subsets towards functional cardiomyocytes, osteoblasts, chondrocytes, muscle, hematopoietic and neural cells was also obtained in vitro or in vivo. Adipose tissue thus appears as a complex tissue composed of different cell subsets that could vary according to the nature and the location of fat pads, or to the physiological or pathological status. WAT appears as a very plastic and heterogeneous tissue that is very easy to sample. This represents a great advantage when considering adipose tissue as a potential and suitable source of stem cell for cell therapy. Further investigations in this way have to lead to the emergence of new insights fundamental to progress in our knowledge of adipose tissue biology.

The role of inflammation and oxidative stress in the development of obesity and associated metabolic disorders is under debate. We investigated the redox metabolism in a non-diabetic obesity model, i.e. 11-week-old obese Zucker rats. Antioxidant enzyme activities, lipophilic antioxidant (alpha-tocopherol, coenzymes Q) and hydrophilic antioxidant (glutathione, vitamin C) contents and their redox state (% oxidized form), were studied in inguinal white fat and compared with blood and liver. The adipose tissues of obese animals showed a specific higher content of hydrophilic molecules in a lower redox state than those of lean animals, which were associated with lower lipophilic molecule content and lipid peroxidation. Conversely and as expected, glutathione content decreased and its redox state increased in adipose tissues of rats subjected to lipopolysaccharide-induced systemic oxidative stress. In these in vivo models, oxidative stress and obesity thus had opposite effects on adipose tissue redox state. Moreover, the increase in glutathione content and the decrease of its redox state by antioxidant treatment promoted in vitro the accumulation of triglycerides in preadipocytes. Taken together and contrary to the emergent view, our results suggest that obesity is associated with an intracellular reduced redox state that promotes on its own the development of a deleterious proadipogenic process.

Introduction L’inhibition de la lipolyse adipocytaire ameliore la sensibilite a l’insuline in vivo et in vitro. Au vu des connaissances actuelles, nous avons pose l’hypothese que l’amelioration de la reponse a l’insuline observee lors d’une inhibition de la Lipase hormono-sensible (LHS) est dirigee par l’augmentation de la voie de la lipogenese de novo (LDN), sous le controle du facteur de transcription ChREBP. Materiels et methodes Dans des preadipocytes humains en culture (cellules hMADS), l’inhibition de l’expression de la LHS (siLHS), du facteur ChREBP (siChREBP) ou des deux (siLHS/siChREBP) est realisee a l’aide de petits ARN interferents. Le metabolisme du glucose est evalue a l’aide de glucose radiomarque. L’expression des differentes enzymes dirigeant la LDN a ete mesuree par RT-qPCR. La composition intra-cellulaire en acides gras a ete determinee par chromatographie en phase gazeuse. Enfin, la transmission du signal insulinique a ete evaluee par Western Blot. Resultats Les adipocytes siLHS presentent une amelioration du transport et de l’oxydation du glucose ainsi que de la LDN en reponse a l’insuline en parallele a une forte augmentation de l’expression du facteur ChREBP. Ces cellules ont aussi une meilleure transmission du signal insulinique. La perte de ces effets dans les adipocytes siLHS/siChREBP suggere un role important de ce facteur dans les effets medies par l’inhibition de la LHS. L’amelioration de la reponse a l’insuline des adipocytes siLHS pourrait s’expliquer par une augmentation de l’oleate au detriment du palmitoleate qui est partiellement perdue dans les cellules siLHS/siChREBP. Une expression differentielle de l’elongase ELOVL6 pourrait notamment expliquer ces differences. Conclusion Ces resultats mettent en evidence l’implication de la LDN, induite par l’augmentation du facteur ChREBP, dans l’amelioration de la sensibilite a l’insuline adipocytaire observee lors d’une inhibition de la LHS. Declaration d’interet Les auteurs declarent ne pas avoir d’interet direct ou indirect (financier ou en nature) avec un organisme prive, industriel ou commercial en relation avec le sujet presente.

TNF-α is a pleiotropic cytokine activating several signaling pathways initiated at distinct intracellular domains of the TNF receptors. Although the C-terminal region is believed to be responsible for apoptosis induction, the functions of more membrane-proximal domains, including the domain that couples to neutral sphingomyelinase activation, are not yet fully elucidated. The roles of this region and of the associated adapter protein FAN (factor associated with neutral SMase activation) in the cytotoxic response to TNF have been investigated. We have now shown that stable expression in human fibroblasts of a dominant negative form of FAN abrogates TNF-induced ceramide generation from sphingomyelin hydrolysis and reduces caspase processing, thus markedly inhibiting TNFtriggered apoptosis. However, the cytotoxic responses to daunorubicin and exogenous ceramide remain unaltered, as do the TNF-induced p42/p44 MAPK activation and CD54 expression. Fibroblasts from FAN-knockout mice also proved to be resistant to TNF toxicity. These findings highlight the previously unrecognized role of the adapter protein FAN in signaling cell death induction by TNF. J. Clin. Invest. 108:143‐151 (2001). DOI:10.1172/JCI200111498.

Human lymphocytes derived from the peripheral blood of a healthy woman were transfected with a plasmid carrying the simian virus 40 (SV40) large T antigen. The successfully transformed cells contained SV40 large T DNA and were negative for Epstein-Barr virus (EBV) and human T-cell leukaemia virus (HTLV)-1 genomes. The immortalized cell line was assigned to the T-lymphocyte lineage on the basis of morphological, immunological and cytochemical criteria. While the cells expressed CD1a and CD4 at the cell surface, the CD3 complex was solely intracytoplasmic. Immunoprecipitation studies indicated that these cells lacked T-cell receptor (TCR) alpha-chains but not beta-chains. They were negative for activation markers such as CD25, CD69 and major histocompatibility (MHC) class II molecules. In addition, the transformed cells exhibited a complete growth independency towards interleukin-2 (IL-2). However, after phorbol ester stimulation, CD25 and CD69 markers were expressed and IL-2 was secreted. This new human immortalized T-lymphocytic cell line, which is cell-surface TCR/CD3-negative, may be useful as an in vitro model for studying TCR/CD3 assembly, expression and signal transduction.

Oxidized low density lipoproteins (oxLDL) are thought to play a central role in the development of atherosclerosis. Toxic concentrations of mildly oxidized LDL elicit massive apoptosis of endothelial cells (Escargueil-Blanc, I., Meilhac, O., Pieraggi, M. T., Arnal J. F., Salvayre, R., Negre-Salvayre, A. (1997)Arterioscler. Thromb. Vasc.Biol. 17, 331–339). Since the lipid mediator ceramide emerged as a potent inducer of apoptosis, we aimed at investigating the occurrence of ceramide formation and its potential role in oxLDL-induced apoptosis. In ECV-304 endothelial cells, toxic concentrations of oxLDL triggered an early activation of the sphingomyelin-ceramide pathway, as shown by both sphingomyelin hydrolysis and ceramide formation.N-Tosyl-l-phenylalanyl chloromethyl ketone (TPCK) and dichloroisocoumarin (DCIC), two serine-protease inhibitors (serpins), blocked the oxLDL-induced ceramide generation but, unexpectedly, did not inhibit the oxLDL-induced apoptosis. Conversely, treatment of endothelial cells by bacterial sphingomyelinase, under conditions effectively generating ceramide, did not induce apoptosis. In contrast, short-chain permeant C2- and C6-ceramides elicited apoptosis of ECV-304. However, the mechanisms of apoptosis triggered by C2-ceramide and by oxLDL were (at least in part) different, because C2-ceramide-induced apoptosis was calcium-independent, whereas oxLDL-induced apoptosis was calcium-dependent. In conclusion, it is suggested that oxLDL-induced apoptosis is calcium-dependent but independent of the activation of the sphingomyelin-ceramide pathway and that the toxic effect of short chain permeant ceramides is calcium-independent and does not mimic the effect of natural ceramides induced by oxLDL.