Evaluation of the early changes occurring in the draining lymph node upon subcutaneous stimulation

Adjuvants have been shown since many years to have an important role in enhancing the immune responses against the co-administered antigens used as vaccines. The continuous study of the mechanism of action of adjuvants is necessary to develop further safe and efficacious vaccines. Complete Freund's adjuvant (CFA) is currently in use as adjuvant to induce some autoimmune diseases in murine models, therefore the study of the mechanisms involved in the generation of the related immune responses could be instrumental for the understanding of the induction of inflammatory Thl7 responses. In the present work, we showed in C57B1/6 mice that CFA peripheral administration induces very early, at 6 h, a potent influx of CDllb+ cells, mainly neutrophils (CD11b+Ly6GhighLy6Cint) and monocytes (CD11b+Ly6GlowLy6Chigh), in the draining lymph node. By investigating the route by which neutrophils reach the lymph node we observed that, around 20% of them arrive from the afferent lymph and the majority stains positive for Mycobacterium tuberculosis. We also observed a correlation between the influx of neutrophils and an increase in IL-23 and IL-Ιβ, together with several inflammatory chemokines, in the draining lymph node. Concomitantly, we detected the expression of the IL-23 receptor on CDllc+ DCs. Moreover, we confirmed the ability of murine neutrophils to express IL-23 both, in vitro by stimulating bone-marrow extracted PMNs with Mycobacterium tuberculosis, and on total cells from draining lymph node by immunohistochemistry. We also observed by in vivo priming a reduction in the percentage of IFN-γ and CXCR3 expressing Τ cells upon depletion of neutrophils. Altogether, we show that upon stimulation from the periphery, the draining lymph node undergo changes in cytokine/chemokine production leading to the recruitment of different leukocytes subpopulations. Here we show that CFA induces a rapid influx of neutrophils which are responsible for the production of IL-23 that in turn influences the generation of Τ helper cells.

Reproducibility and within-day variability of body fat measurements using segmental bipolar bioelectrical impedance in women

BACKGROUND AND AIMS: little is known regarding the reproducibility of body fat measuring devices; hence, we assessed the between and within-device reproducibility, and the within-day variability of body fat measurements. METHODS: body fat percentage was measured twice on seventeen female students aged between 18 and 20 with a body mass index of 21.9 ± 2.5 kg/m2 (mean ± SD) using seven bipolar bioelectrical impedance devices. Each participant was also measured each hour between 7:00 and 22:00. RESULTS: the correlation between first and second measurements was very high (Spearman r between 0.985 and 1.000, p<0.001), as well as between devices (Spearman r between 0.916 and 0.991, p<0.001). Repeated measurements analysis showed no differences were between devices (p=0.59) or readings (first vs. second: p=0.74). Conversely, significant differences were found between assessment periods throughout the day, measurements made in the morning being lower than those made in the afternoon (F test for repeated values= 6.58, p<0.001). CONCLUSIONS: the between and within-device reproducibility for measuring body fat is high, enabling the use of multiple devices in a single study. Conversely, small but significant changes in body fat measurements occur during the day, urging body fat measurements to be performed at fixed times.

Gastric bypass in morbid obese patients is associated with reduction in adipose tissue inflammation via N-oleoylethanolamide (OEA)-mediated pathways.

Paradoxically, morbid obesity was suggested to protect from cardiovascular co-morbidities as compared to overweight/obese patients. We hypothesise that this paradox could be inferred to modulation of the "endocannabinoid" system on systemic and subcutaneous adipose tissue (SAT) inflammation. We designed a translational project including clinical and in vitro studies at Geneva University Hospital. Morbid obese subjects (n=11) were submitted to gastric bypass surgery (GBS) and followed up for one year (post-GBS). Insulin resistance and circulating and SAT levels of endocannabinoids, adipocytokines and CC chemokines were assessed pre- and post-GBS and compared to a control group of normal and overweight subjects (CTL) (n=20). In vitro cultures with 3T3-L1 adipocytes were used to validate findings from clinical results. Morbid obese subjects had baseline lower insulin sensitivity and higher hs-CRP, leptin, CCL5 and anandamide (AEA) levels as compared to CTL. GBS induced a massive weight and fat mass loss, improved insulin sensitivity and lipid profile, decreased C-reactive protein, leptin, and CCL2 levels. In SAT, increased expression of resistin, CCL2, CCL5 and tumour necrosis factor and reduced MGLL were shown in morbid obese patients pre-GBS when compared to CTL. GBS increased all endocannabinoids and reduced adipocytokines and CC chemokines. In morbid obese SAT, inverse correlations independent of body mass index were shown between palmitoylethanolamide (PEA) and N-oleoylethanolamide (OEA) levels and inflammatory molecules. In vitro, OEA inhibited CCL2 secretion from adipocytes via ERK1/2 activation. In conclusion, GBS was associated with relevant clinical, metabolic and inflammatory improvements, increasing endocannabinoid levels in SAT. OEA directly reduced CCL2 secretion via ERK1/2 activation in adipocytes.

Athletic injuries of the extensor carpi ulnaris subsheath: MRI findings and utility of gadolinium-enhanced fat-saturated T1-weighted sequences with wrist pronation and supination

Purpose: To report the magnetic resonance imaging (MRI) findings in athletic injuries of the extensor carpi ulnaris (ECU) subsheath, assessing the utility of gadolinium-enhanced (Gd) fat-saturated (FS) T1-weighted sequences with wrist pronation and supination. Methods and Materials: Sixteen patients (13 males, 3 females; mean age 30.3 years) with athletic injuries of the ECU subsheath sustained between January 2003 and June 2009 were included in this retrospective study. Initial and follow‑up 1.5-T wrist MRIs were performed with transverse T1-weighted and STIR sequences in pronation, and Gd FS T1-weighted sequences with wrist pronation and supination. Two radiologists assessed the type of injury (A to C), ECU tendon stability, associated lesions and rated pulse sequences using a three-point scale: 1 = poor, 2 = good and 3 = excellent. Results: Gd-enhanced FS T1-weighted transverse sequences in supination (2.63) and pronation (2.56) were most valuable, compared with STIR (2.19) and T1 weighted (1.94). Nine type A, one type B and six type C injuries were found. There were trends towards diminution in size, signal intensity and enhancement of associated pouches on follow‑up MRI and tendon stabilisation within the ulnar groove. Conclusion: Gd-enhanced FS T1-weighted sequences with wrist pronation and supination are most valuable in assessing and follow‑up athletic injuries of the ECU subsheath on 1.5-T MRI.

Gender differences in whole-body fat oxidation kinetics during exercise.

Discrepancies appear in studies comparing fat oxidation between men and women. Therefore, this study aimed to quantitatively describe and compare whole-body fat oxidation kinetics between genders during exercise, using a sinusoidal (SIN) model. Twelve men and 11 women matched for age, body mass index, and aerobic fitness (maximal oxygen uptake and maximal power output per kilogram of fat-free mass (FFM)) performed submaximal incremental tests (Incr) with 5-min stages and a 7.5% maximal power output increment on a cycle ergometer. Fat oxidation rates were determined using indirect calorimetry, and plotted as a function of exercise intensity. The SIN model, which includes 3 independent variables (dilatation, symmetry, translation) that account for the main quantitative characteristics of kinetics, was used to mathematically describe fat oxidation kinetics and to determine the intensity (Fatmax) eliciting the maximal fat oxidation (MFO). During Incr, women exhibited greater fat oxidation rates from 35% to 85% maximal oxygen uptake, MFO (6.6 ± 0.9 vs. 4.5 ± 0.3 mg·kg FFM-1·min-1), and Fatmax (58.1% ± 1.9% vs. 50.0% ± 2.7% maximal oxygen uptake) than men (p < 0.05). While men and women showed similar global shapes of fat oxidation kinetics in terms of dilatation and symmetry (p > 0.05), the fat oxidation curve tended to be shifted toward higher exercise intensities in women (rightward translation, p = 0.08). These results support the idea that women have a greater reliance on fat oxidation than men during submaximal exercise, but also indicate that this greater fat oxidation is shifted toward higher exercise intensities in women than in men.

Hepatic stereology of schistosomiasis mansoni infected-mice fed a high-fat diet

High-fat diets induce weight gain and fatty liver in wild-type mice. Schistosomiasis mansoni infection also promotes hepatic injury. This study was designed to quantify hepatic alterations in schistosomiasis mansoni-infected mice fed a high fat-rich chow compared to mice fed a standard rodent chow, using stereology. Female SW mice fed each either high-fat diet (29% lipids) or standard chow (12% lipids) over 8 months, and then were infected with Schistosoma mansoni cercariae. Four experimental groups were studied: infected mice fed a high-fat diet (IHFC) or standard chow (ISC), uninfected mice fed a high-fat diet (HFC) or standard chow (SC). Mice were sacrificed during early infection (9 weeks from exposure). The following hepatic biometry and the stereology parameters were determined: volume density (hepatocytes [h], sinusoids [s], steatosis [st] and hepatic fibrosis [hf]); numerical density (hepatocyte nuclei - Nv[h]); absolute number of total hepatocyte N[h], normal hepatocyte N[nh], and binucleated hepatocyte N[bh], percentage of normal hepatocyte P[nh] and binucleated hepatocyte P[bh]. IHFC and HFC groups exhibited TC, HDL-C, LDL-C, and body mass significantly greater (p < 0.05) than control group. No significant differences were found regards liver volume (p = 0.07). Significant differences were observed regards P[nh] (p = 0.0045), P[bh] (p = 0.0045), Nv[h] (p = 0.0006), N[h] (p = 0.0125), N[bh] (p = 0.0164) and N[nh] (p = 0.0078). IHFC mice group presented 29% of binucleated hepatocytes compared to HFC group (19%), ISC group (17%) and SC (6%). Volume density was significantly different between groups: Vv[h] (p = 0.0052), Vv[s] (p = 0.0025), Vv[st] (p = 0.0004), and Vv[hf] (p = 0.0007). In conclusion, schistosomiasis mansoni infection with concurrent high-fat diet promotes intensive quantitative changes in hepatic structure, contributing to an increasing on hepatic regeneration.

Effect of acute and chronic exercise on fat oxidation and hormonal and plasma metabolite kinetics in obese and severely obese men

Acute exercise increases energy expenditure (EE) during exercise and post-exercise recovery [excess post-exercise oxygen consumption (EPOC)] and therefore may be recommended as part of the multidisciplinary management of obesity. Moreover, chronic exercise (training) effectively promotes an increase in insulin sensitivity, which seems to be associated with increased fat oxidation rates (FORs). The main purpose of this thesis is to investigate 1) FORs and extra-muscular factors (hormones and plasma metabolites) that regulate fat metabolism during acute and chronic exercise; and 2) EPOC during acute post-exercise recovery in obese and severely obese men (class II and III). In the first study, we showed that obese and severely obese men present a lower exercise intensity (Fatmax) eliciting maximal fat oxidation and a lower reliance on fat oxidation at high, but not at low and moderate, exercise intensities compared to lean men. This was most likely related to an impaired muscular capacity to oxidize non-esterified fatty acids (NEFA) rather than decreased plasma NEFA availability or a change in the hormonal milieu during exercise. In the second study, we developed an accurate maximal incremental test to correctly and simultaneously evaluate aerobic fitness and fat oxidation kinetics during exercise in this population. This test may be used for the prescription of an appropriate exercise training intensity. In the third study, we demonstrated that only 2 wk of exercise training [continuous training at Fatmax and adapted high-intensity interval training (HIIT)], matched with respect to mechanical work, may be effective to improve aerobic fitness, FORs during exercise and insulin sensitivity, which suggest that FORs might be rapidly improved and that adapted HIIT is feasible in this population. The increased FORs concomitant with the lack of changes in lipolysis during exercise suggest an improvement in the mismatching between NEFA availability and oxidation, highlighting the importance of muscular (oxidative capacity) rather than extra-muscular (hormones and plasma metabolites) factors in the regulation of fat metabolism after a training program. In the fourth study, we observed a positive correlation between EE during exercise and EPOC, suggesting that a chronic increase in the volume or intensity of exercise may increase EE during exercise and during recovery. This may have an impact in weight management in obesity. In conclusion, these findings might have practical implications for exercise training prescriptions in order to improve the therapeutic approaches in obesity and severe obesity. -- L'exercice aigu augmente la dépense énergétique (DE) pendant l'exercice et la récupération post-exercice [excès de consommation d'oxygène post-exercise (EPOC)] et peut être utilisé dans la gestion multidisciplinaire de l'obésité. Quant à l'exercice chronique (entraînement), il est efficace pour augmenter la sensibilité à l'insuline, ce qui semble être associé à une amélioration du débit d'oxydation lipidique (DOL). Le but de cette thèse est d'étudier 1) le DOL et les facteurs extra-musculaires (hormones et métabolites plasmatiques) qui régulent le métabolisme lipidique pendant l'exercice aigu et chronique et 2) l'EPOC lors de la récupération aiguë post-exercice chez des hommes obèses et sévèrement obèses (classe II et III). Dans la première étude nous avons montré que les hommes obèses et sévèrement obèses présentent une plus basse intensité d'exercice (Fatmax) correspondant au débit d'oxydation lipidique maximale et un plus bas DOL à hautes, mais pas à faibles et modérées, intensités d'exercice comparé aux sujets normo-poids, ce qui est probablement lié à une incapacité musculaire à oxyder les acides gras non-estérifiés (AGNE) plutôt qu'à une diminution de leur disponibilité ou à un changement du milieu hormonal pendant l'exercice. Dans la deuxième étude nous avons développé un test maximal incrémental pour évaluer simultanément l'aptitude physique aérobie et la cinétique d'oxydation des lipides pendant l'exercice chez cette population. Dans la troisième étude nous avons montré que seulement deux semaines d'entraînement (continu à Fatmax et intermittent à haute intensité), appariés par la charge de travail, sont efficaces pour améliorer l'aptitude physique aérobie, le DOL pendant l'exercice et la sensibilité à l'insuline, ce qui suggère que le DOL peut être rapidement amélioré chez cette population. Ceci, en absence de changements de la lipolyse pendant l'exercice, suggère une amélioration de la balance entre la disponibilité et l'oxydation des AGNE, ce qui souligne l'importance des facteurs musculaires (capacité oxydative) plutôt que extra-musculaires (hormones et métabolites plasmatiques) dans la régulation du métabolisme lipidique après un entraînement. Dans la quatrième étude nous avons observé une corrélation positive entre la DE pendant l'exercice et l'EPOC, ce qui suggère qu'une augmentation chronique du volume ou de l'intensité de l'exercice pourrait augmenter la DE lors de l'exercice et lors de la récupération post-exercice. Ceci pourrait avoir un impact sur la gestion du poids chez cette population. En conclusion, ces résultats pourraient avoir des implications pratiques lors de la prescription des entraînements dans le but d'améliorer les approches thérapeutiques de l'obésité et de l'obésité sévère.

Depression with atypical features and increase in obesity, body mass index, waist circumference, and fat mass: a prospective, population-based study.

IMPORTANCE: Depression and obesity are 2 prevalent disorders that have been repeatedly shown to be associated. However, the mechanisms and temporal sequence underlying this association are poorly understood. OBJECTIVE: To determine whether the subtypes of major depressive disorder (MDD; melancholic, atypical, combined, or unspecified) are predictive of adiposity in terms of the incidence of obesity and changes in body mass index (calculated as weight in kilograms divided by height in meters squared), waist circumference, and fat mass. DESIGN, SETTING, AND PARTICIPANTS: This prospective population-based cohort study, CoLaus (Cohorte Lausannoise)/PsyCoLaus (Psychiatric arm of the CoLaus Study), with 5.5 years of follow-up included 3054 randomly selected residents (mean age, 49.7 years; 53.1% were women) of the city of Lausanne, Switzerland (according to the civil register), aged 35 to 66 years in 2003, who accepted the physical and psychiatric baseline and physical follow-up evaluations. EXPOSURES: Depression subtypes according to the DSM-IV. Diagnostic criteria at baseline and follow-up, as well as sociodemographic characteristics, lifestyle (alcohol and tobacco use and physical activity), and medication, were elicited using the semistructured Diagnostic Interview for Genetic Studies. MAIN OUTCOMES AND MEASURES: Changes in body mass index, waist circumference, and fat mass during the follow-up period, in percentage of the baseline value, and the incidence of obesity during the follow-up period among nonobese participants at baseline. Weight, height, waist circumference, and body fat (bioimpedance) were measured at baseline and follow-up by trained field interviewers. RESULTS: Only participants with the atypical subtype of MDD at baseline revealed a higher increase in adiposity during follow-up than participants without MDD. The associations between this MDD subtype and body mass index (β = 3.19; 95% CI, 1.50-4.88), incidence of obesity (odds ratio, 3.75; 95% CI, 1.24-11.35), waist circumference in both sexes (β = 2.44; 95% CI, 0.21-4.66), and fat mass in men (β = 16.36; 95% CI, 4.81-27.92) remained significant after adjustments for a wide range of possible cofounding. CONCLUSIONS AND RELEVANCE: The atypical subtype of MDD is a strong predictor of obesity. This emphasizes the need to identify individuals with this subtype of MDD in both clinical and research settings. Therapeutic measures to diminish the consequences of increased appetite during depressive episodes with atypical features are advocated.

High fat diet has a prominent effect upon the course of chronic schistosomiasis mansoni in mice

This study investigated whether a long-term high-fat diet has an effect on the outcome of chronic murine schistosomiasis mansoni compared to a standard diet. Swiss Webster female mice (3 weeks old) were fed each diet for up to six months and were then infected with 50 Schistosoma mansoni cercariae. Their nutritional status was assessed by monitoring total serum cholesterol and body mass. Infected mice were examined 6-17 weeks post infection to estimate the number of eggs in faeces. Mice were euthanised the next day. Total serum cholesterol was lower in infected mice in comparison to uninfected controls (p = 0.0055). In contrast, body mass (p = 0.003), liver volume (p = 0.0405), spleen volume (p = 0.0124), lung volume (p = 0.0033) and faecal (p = 0.0064) and tissue egg density (p = 0.0002) were significantly higher for infected mice fed a high-fat diet. From these findings, it is suggested that a high-fat diet has a prominent effect on the course of chronic schistosomiasis mansoni in mice.

Assessment of adipose tissue metabolism by means of subcutaneous microdialysis in patients with sepsis or circulatory failure.

To evaluate the role of adipose tissue in the metabolic stress response of critically ill patients, the release of glycerol and lactate by subcutaneous adipose tissue was assessed by means of microdialysis in patients with sepsis or circulatory failure and in healthy subjects. Patients with sepsis had lower plasma free fatty acid concentrations and non-significant elevations of plasma glycerol concentrations, but higher adipose-systemic glycerol concentrations gradients than healthy subjects or patients with circulatory failure, indicating a stimulation of subcutaneous adipose lipolysis. They also had a higher lipid oxidation. Lipid metabolism (adipose-systemic glycerol gradients, lipid oxidation) was not altered in patients with circulatory failure. These observations highlight major differences in lipolysis and lipid utilization between patients with sepsis and circulatory failure. Hyperlactataemia was present in both groups of patients, but the adipose-systemic lactate concentration gradient was not increased, indicating that lactate production by adipose tissue was not involved. This speaks against a role of adipose tissue in the development of hyperlactataemia in critically ill patients.