Effects of targeted delivery of propionate to the human colon on appetite regulation, body weight maintenance and adiposity in overweight adults.

OBJECTIVE: The colonic microbiota ferment dietary fibres, producing short chain fatty acids. Recent evidence suggests that the short chain fatty acid propionate may play an important role in appetite regulation. We hypothesised that colonic delivery of propionate would increase peptide YY (PYY) and glucagon like peptide-1 (GLP-1) secretion in humans, and reduce energy intake and weight gain in overweight adults. DESIGN: To investigate whether propionate promotes PYY and GLP-1 secretion, a primary cultured human colonic cell model was developed. To deliver propionate specifically to the colon, we developed a novel inulin-propionate ester. An acute randomised, controlled cross-over study was used to assess the effects of this inulin-propionate ester on energy intake and plasma PYY and GLP-1 concentrations. The long-term effects of inulin-propionate ester on weight gain were subsequently assessed in a randomised, controlled 24-week study involving 60 overweight adults. RESULTS: Propionate significantly stimulated the release of PYY and GLP-1 from human colonic cells. Acute ingestion of 10 g inulin-propionate ester significantly increased postprandial plasma PYY and GLP-1 and reduced energy intake. Over 24 weeks, 10 g/day inulin-propionate ester supplementation significantly reduced weight gain, intra-abdominal adipose tissue distribution, intrahepatocellular lipid content and prevented the deterioration in insulin sensitivity observed in the inulin-control group. CONCLUSIONS: These data demonstrate for the first time that increasing colonic propionate prevents weight gain in overweight adult humans. TRIAL REGISTRATION NUMBER: NCT00750438.

Immune cell-mediated inflammation and the early improvements in glucose metabolism after gastric banding surgery.

AIMS/HYPOTHESIS: The contribution of immune cells to the inflammasome that characterises type 2 diabetes mellitus and obesity is under intense research scrutiny. We hypothesised that early changes in glucose metabolism following gastric banding surgery may relate to systemic inflammation, particularly cell-mediated immunity. METHODS: Obese participants (BMI 43.4 ± 4.9 kg/m(2), n = 15) with diabetes or impaired glucose tolerance (IGT) underwent laparoscopic adjustable gastric banding surgery. Measurements taken before, and at 2 and 12 weeks after surgery included: fasting glucose, glucose levels 2 h after a 75 g oral load, glucose incremental AUC, oral glucose insulin sensitivity index (OGIS), circulating immune cell numbers and activation, and adipokine levels. Subcutaneous and visceral adipose tissue were collected at surgery, and macrophage number and activation measured. RESULTS: There were significant reductions in fasting and 2 h glucose, as well as improved OGIS at 2 and 12 weeks. At 12 weeks, 80% of the diabetic participants reverted to normal glucose tolerance or IGT, and all IGT participants had normalised glucose tolerance. The 12 week fall in fasting glucose was significantly related to baseline lymphocyte and T lymphocyte numbers, and to granulocyte activation, but also to the magnitude of the 12 week reduction in lymphocyte and T lymphocyte numbers and TNF-α levels. In a model that explained 75% of the variance in the change in fasting glucose, the 12 week change in T lymphocytes was independently associated with the 12 week fall in fasting glucose. CONCLUSIONS/INTERPRETATION: Rapid improvements in glucose metabolism after gastric banding surgery are related to reductions in circulating pro-inflammatory immune cells, specifically T lymphocytes. The contribution of immune cell-mediated inflammation to glucose homeostasis in type 2 diabetes and its improvement after bariatric surgery require further investigation.

Postprandial cardiac autonomic function in Prader-Willi syndrome.

CONTEXT: Individuals with Prader-Willi syndrome (PWS) have a high cardiovascular risk, the mechanism of which is unclear. There may be dysfunction in the autonomic nervous system (ANS) in PWS. OBJECTIVE: To measure, as indicators of cardiac autonomic function, postprandial heart rate variability (HRV) and arterial stiffness in adults with PWS. METHODS: Ten adults with PWS were compared with 11 matched healthy obese subjects and 9 healthy lean subjects. Electrocardiographic traces and arterial stiffness were recorded over a period of 10 minutes at -60, 0, 30, 60, 120 and 240 minutes after consumption of a standardized 600-kCal breakfast. Frequency domain analysis was performed using fast Fourier transform to estimate power spectral density in the full spectrum and in low-frequency (LF 0·04-0·15 Hz) and high-frequency (HF 0·15-0·40 Hz) bands. RESULTS: ANCOVA revealed a reduced LF HRV meal response in adults with PWS compared with obese controls, with no differences in HF HRV, LF/HF ratio, heart rate, total power or arterial stiffness meal responses. CONCLUSIONS: This study assessed cardiac autonomic function in adults with PWS compared with matched obese and lean subjects in response to a meal. Results suggest impaired postprandial ANS responsiveness in PWS, which could contribute to both the known increased cardiovascular risk and obesity.

Connecting the Dots of Care: A pilot study linking Aboriginal and/or Torres Strait Islander peoples with diabetes care in hospital, using hospital pharmacists.

Background: Diabetes is common among Aboriginal and/or Torres Strait Islander peoples, yet often undetected in hospital. Objective: To identify how urban hospital pharmacists can detect if Aboriginal and/or Torres Strait Islander patients have diabetes or a higher chance of getting diabetes. Methods: A multi-methods study used data from patients, and researcher field notes. Aboriginal and/or Torres Strait Islander peoples admitted to hospital over 12-weeks (July-October 2021) were prospectively identified from admissions lists. A hospital pharmacist-researcher visited eligible patients. Consenting participants had their blood glucose and HbA1c checked. Participants with HbA1c > 6.5% (no known diabetes) or 7% (known diabetes) were referred for endocrinology review during their stay. Test results and resultant diabetes plan were shared with their general practitioner. Two days after discharge, participants were called to gauge views on their hospital-based diabetes care. Barcode technology recorded pharmacist time. Voice-recorded field notes were thematically analysed. Ethics approval was obtained. Results: Seventy-two patients were eligible for inclusion, 67/72 (93%) consented to take part. Sixty-one (91%) patients returned a HbA1c < 6.5, of which, 4/61 (6.5%) returned a HbA1c, 6-6.4. They were contacted to yarn about diabetes prevention. Six of the 67 (9%) qualified for endocrine review, 5 had known diabetes, one newly diagnosed. None were known to endocrinology. All participants telephoned were satisfied with their hospital-based diabetes care. Pharmacist time for initial introductory yarn, consenting process, organisation of HbA1c and results discussion was 20 min or 40 min if referred for endocrine review. Field notes guided understanding of service implementation. Conclusion: This novel pharmacist-led diabetes screening service for Aboriginal and/or Torres Strait Islander peoples appeared to provide a unique opportunity for screening and referral links in a holistic way. Future research is required to test this model by upscaling to include more pharmacists and other chronic disease screening and referral pathways.

Relative Contributions of Lean and Fat Mass to Bone Mineral Density: Insight From Prader-Willi Syndrome.

Context: Low bone mineral density (BMD) is the most important risk factor for fragility fracture. Body weight is a simple screening predictor of difference in BMD between individuals. However, it is not clear which component of body weight, lean (LM), or fat mass (FM), is associated with BMD. People with the genetic disorder of Prader-Willi syndrome (PWS) uniquely have a reduced LM despite increased FM. Objective: We sought to define the individual impact of LM and FM on BMD by investigating subjects with and without PWS. Design, Setting and Participants: This cross-sectional study was conducted at the Clinical Research Facility of the Garvan Institute of Medical Research, with PWS and control participants recruited from a specialized PWS clinic and from the general public by advertisement, respectively. The study involved 11 adults with PWS, who were age- and sex-matched with 12 obese individuals (Obese group) and 10 lean individuals (Lean group). Main Outcome Measures: Whole body BMD was measured by dual-energy X-ray absorptiometry. Total body FM and LM were derived from the whole body scan. Differences in BMD between groups were assessed by the analysis of covariance model, taking into account the effects of LM and FM. Results: The PWS group had significantly shorter height than the lean and obese groups. As expected, there was no significant difference in FM between the Obese and PWS group, and no significant difference in LM between the Lean and PWS group. However, obese individuals had greater LM than lean individuals. BMD in lean individuals was significantly lower than in PWS individuals (1.13 g/cm2 vs. 1.21 g/cm2, p < 0.05) and obese individuals (1.13 g/cm2 vs. 1.25 g/cm2, p < 0.05). After adjusting for both LM and FM, there was no significant difference in BMD between groups, and the only significant predictor of BMD was LM. Conclusions: These data from the human genetic model Prader-Willi syndrome suggest that LM is a stronger determinant of BMD than fat mass.

Potential antiinflammatory role of insulin via the preferential polarization of effector T cells toward a T helper 2 phenotype.

Hyperglycemia in critical illness is a common complication and a strong independent risk factor for morbidity and death. Intensive insulin therapy decreases this risk by up to 50%. It is unclear to what extent this benefit is due to reversal of glucotoxicity or to a direct effect of insulin, because antiinflammatory effects of insulin have already been described, but the underlying mechanisms are still poorly understood. The insulin receptor is expressed on resting neutrophils, monocytes, and B cells, but is not detectable on T cells. However, significant up-regulation of insulin receptor expression is observed on activated T cells, which suggests an important role during T cell activation. Exogenous insulin in vitro induced a shift in T cell differentiation toward a T helper type 2 (Th2)-type response, decreasing the T helper type 1 to Th2 ratio by 36%. This result correlated with a corresponding change in cytokine secretion, with the interferon-gamma to IL-4 ratio being decreased by 33%. These changes were associated with increased Th2-promoting ERK phosphorylation in the presence of insulin. Thus, we demonstrate for the first time that insulin treatment influences T cell differentiation promoting a shift toward a Th2-type response. This effect of insulin in changing T cell polarization may contribute to its antiinflammatory role not only in sepsis, but also in chronic inflammation associated with obesity and type 2 diabetes.

Fermentable carbohydrate stimulates FFAR2-dependent colonic PYY cell expansion to increase satiety.

OBJECTIVE: Dietary supplementation with fermentable carbohydrate protects against body weight gain. Fermentation by the resident gut microbiota produces short-chain fatty acids, which act at free fatty acid receptor 2 (FFAR2). Our aim was to test the hypothesis that FFAR2 is important in regulating the beneficial effects of fermentable carbohydrate on body weight and to understand the role of gut hormones PYY and GLP-1. METHODS: Wild-type or Ffar2-/- mice were fed an inulin supplemented or control diet. Mice were metabolically characterized and gut hormone concentrations, enteroendocrine cell density measurements were carried out. Intestinal organoids and colonic cultures were utilized to substantiate the in vivo findings. RESULTS: We provide new mechanistic insight into how fermentable carbohydrate regulates metabolism. Using mice that lack FFAR2, we demonstrate that the fermentable carbohydrate inulin acts via this receptor to drive an 87% increase in the density of cells that produce the appetite-suppressing hormone peptide YY (PYY), reduce food intake, and prevent diet-induced obesity. CONCLUSION: Our results demonstrate that FFAR2 is predominantly involved in regulating the effects of fermentable carbohydrate on metabolism and does so, in part, by enhancing PYY cell density and release. This highlights the potential for targeting enteroendocrine cell differentiation to treat obesity.

Reproducibility of nighttime salivary cortisol and its use in the diagnosis of hypercortisolism compared with urinary free cortisol and overnight dexamethasone suppression test.

BACKGROUND/METHODS: Nighttime salivary cortisol (NSC) has been suggested to be a useful diagnostic test for Cushing's syndrome (CS). In the absence of published data on its day-to-day variability, we assessed the reproducibility of NSC by repeated measurements in healthy volunteers. Its diagnostic performance was compared with 24-h urinary free cortisol (UFC) and 1 mg overnight dexamethasone suppression test in 12 patients with CS, 20 healthy volunteers, 14 referred patients in which CS was excluded or not firmly established, 16 obese patients, and 20 women in late pregnancy. RESULTS: NSC showed a superior reproducibility in healthy volunteers with a low day-to-day variability as reflected by an intraclass correlation coefficient of 0.78. The receiver operating characteristic curve-estimated cutoff of 6.1 nmol/liter (0.22 microg/dl) demonstrated a sensitivity and specificity of 100% (area under the receiver operating characteristic curve, 1.0; 95% confidence interval, 0.94-1.0) in the diagnosis of CS. NSC, 24-h UFC [after adjusting the local laboratory cutoff to 504 nmol/d (183 microg/d)], and the urinary cortisol/creatinine ratio showed a tendency to be superior to 1 mg dexamethasone suppression test in correctly identifying CS. In late pregnancy, the preserved diurnal variation at a higher level of salivary cortisol reduced the specificity of NSC to 75%. CONCLUSION: Based on its remarkable reproducibility, easy noninvasive nature, and at least similar diagnostic performance, NSC appears to be a preferable alternative to 24-h UFC as a first-line screening test for CS. The cutoff values of NSC, 24-h UFC, and urinary cortisol/creatinine ratio have to be carefully adjusted using assay and center-specific reference ranges of sufficiently large populations.

Postprandial metabolism in adults with Prader-Willi syndrome.

OBJECTIVE: Individuals with Prader-Willi syndrome (PWS) are commonly restricted to 60-75% of height-appropriate calorie intake because they rapidly become obese on a normal diet. This study measured changes in energy expenditure, glucose and lipid homeostasis, and metabolic flexibility in response to a meal in PWS adults. METHODS: 11 adults with PWS were compared with 12 adiposity-matched and 10 lean subjects. Indirect calorimetry was conducted at baseline and 210 min after a standardized 600 kCal breakfast to assess energy expenditure and substrate utilization. Circulating glucose, insulin, C-peptide, glucagon, nonesterified fatty acids, and triglycerides were measured up to 240 min. Insulin sensitivity and insulin secretion rate were assessed by HOMA-IR and C-peptide deconvolution, respectively. Body composition was determined by dual-energy X-ray absorptiometry. RESULTS: The PWS group had lower lean mass than the obesity control group. Corrected for lean mass, there were no differences between the PWS and obesity groups in resting metabolic rate or metabolic flexibility. Total and abdominal fat mass, insulin sensitivity, and insulin secretion rate were also similar between these groups. CONCLUSIONS: This study did not detect an intrinsic metabolic defect in individuals with PWS. Rather, lower lean mass, combined with lower physical activity, may contribute to weight gain on an apparent weight-maintenance diet.

The short-chain fatty acid acetate reduces appetite via a central homeostatic mechanism.

Increased intake of dietary carbohydrate that is fermented in the colon by the microbiota has been reported to decrease body weight, although the mechanism remains unclear. Here we use in vivo(11)C-acetate and PET-CT scanning to show that colonic acetate crosses the blood-brain barrier and is taken up by the brain. Intraperitoneal acetate results in appetite suppression and hypothalamic neuronal activation patterning. We also show that acetate administration is associated with activation of acetyl-CoA carboxylase and changes in the expression profiles of regulatory neuropeptides that favour appetite suppression. Furthermore, we demonstrate through (13)C high-resolution magic-angle-spinning that (13)C acetate from fermentation of (13)C-labelled carbohydrate in the colon increases hypothalamic (13)C acetate above baseline levels. Hypothalamic (13)C acetate regionally increases the (13)C labelling of the glutamate-glutamine and GABA neuroglial cycles, with hypothalamic (13)C lactate reaching higher levels than the 'remaining brain'. These observations suggest that acetate has a direct role in central appetite regulation.

Reduced arterial stiffness after weight loss in obese type 2 diabetes and impaired glucose tolerance: the role of immune cell activation and insulin resistance.

Weight loss after bariatric surgery reduces cardiac risk and morbidity. We examined weight loss effects on arterial stiffness in morbidly obese subjects, in relation to cytokines, circulating and subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT)-based immune cells and gene expression. Obese subjects with type 2 diabetes mellitus (T2D) or impaired glucose tolerance (n = 14, mean ± SEM body mass index 42.9 kg/m(2)) underwent 24 weeks' caloric restriction, with gastric banding at 12 weeks. Measures were: arterial augmentation index (AIx), insulin resistance, circulating cytokines, immune cell activation markers, and SAT and VAT cytokine gene expression. Weight loss reduced AIx by 20% (p = 0.007), with falls in s-selectin (p = 0.001) and inter-cellular adhesion molecule (p = 0.04). Improved AIx related to reduced surface expression of the interleukin (IL)-2 receptor on T-lymphocytes (TL-IL2R) and granulocyte adhesion markers (r = 0.59, 0.64, respectively, p < 0.04). Higher VAT expression of interferon-γ and monocyte chemoattractant protein-1 associated with a blunted AIx response. A model of TL-IL2R expression, waist, weight and insulin resistance explained 73% of the variance in AIx reduction (p = 0.005). In morbidly obese dysglycaemic subjects, modest weight loss reduces arterial stiffness, the magnitude of which relates to improved markers of inflammation.

Coadministration of glucagon-like peptide-1 during glucagon infusion in humans results in increased energy expenditure and amelioration of hyperglycemia.

Glucagon and glucagon-like peptide (GLP)-1 are the primary products of proglucagon processing from the pancreas and gut, respectively. Giving dual agonists with glucagon and GLP-1 activity to diabetic, obese mice causes enhanced weight loss and improves glucose tolerance by reduction of food intake and by increase in energy expenditure (EE). We aimed to observe the effect of a combination of glucagon and GLP-1 on resting EE and glycemia in healthy human volunteers. In a randomized, double-blinded crossover study, 10 overweight or obese volunteers without diabetes received placebo infusion, GLP-1 alone, glucagon alone, and GLP-1 plus glucagon simultaneously. Resting EE--measured using indirect calorimetry--was not affected by GLP-1 infusion but rose significantly with glucagon alone and to a similar degree with glucagon and GLP-1 together. Glucagon infusion was accompanied by a rise in plasma glucose levels, but addition of GLP-1 to glucagon rapidly reduced this excursion, due to a synergistic insulinotropic effect. The data indicate that drugs with glucagon and GLP-1 agonist activity may represent a useful treatment for type 2 diabetes and obesity. Long-term studies are required to demonstrate that this combination will reduce weight and improve glycemia in patients.

Effects of a single dose of exenatide on appetite, gut hormones, and glucose homeostasis in adults with Prader-Willi syndrome.

CONTEXT: Prader-Willi syndrome (PWS) is associated with hyperphagia and obesity, without effective pharmacological treatment. Exenatide, recently developed for treatment of type 2 diabetes, induces appetite suppression and weight loss with common side effects. OBJECTIVE: The objective of the study was to investigate the initial safety and effectiveness of exenatide in adult PWS subjects compared with obese controls (OBESE). DESIGN, SETTING, PATIENTS, AND INTERVENTION: Eight PWS and 11 OBESE patients underwent standardized meal studies after a single sc injection of 10 µg exenatide or placebo in a single-blinded, crossover design. MAIN OUTCOME MEASURES: Glucose, insulin, C-peptide, glucagon, peptide YY (PYY; total)/PYY (3-36), glucagon-like peptide-1, and ghrelin (total) were measured fasting and postprandially. Appetite and satiety were assessed by visual analog scales. Energy expenditure (EE) was measured by indirect calorimetry. Side effects were screened during and for 24 h after the meal. RESULTS: PWS and OBESE patients were matched for gender, age, body mass index, and central/total body fat. In both groups, exenatide increased satiety and lowered glucose and insulin levels but increased insulin secretion rate. Side effects were absent in PWS but common in OBESE patients. During the meal, PYY (total) and ghrelin were elevated in PWS patients. Exenatide decreased PYY (total) and glucagon-like peptide-1, whereas ghrelin remained unchanged. Energy expenditure was unchanged by exenatide. CONCLUSIONS: Our pilot study demonstrates that exenatide is well tolerated in PWS patients. It increases satiety independently of measured appetite hormones, exerting glucose lowering, and insulinotropic effects similarly in PWS and OBESE patients. Larger prospective studies should investigate whether chronic exenatide administration will reduce hyperphagia and overweight in PWS patients without side effects.

In adults with Prader-Willi syndrome, elevated ghrelin levels are more consistent with hyperphagia than high PYY and GLP-1 levels.

OBJECTIVE: Prader-Willi syndrome (PWS) is a leading genetic cause of obesity, characterized by hyperphagia, endocrine and developmental disorders. It is suggested that the intense hyperphagia could stem, in part, from impaired gut hormone signaling. Previous studies produced conflicting results, being confounded by differences in body composition between PWS and control subjects. DESIGN: Fasting and postprandial gut hormone responses were investigated in a cross-sectional cohort study including 10 adult PWS, 12 obese subjects matched for percentage body fat and central abdominal fat, and 10 healthy normal weight subjects. METHODS: PYY[total], PYY[3-36], GLP-1[active] and ghrelin[total] were measured by ELISA or radioimmunoassay. Body composition was assessed by dual energy X-ray absorptiometry. Visual analog scales were used to assess hunger and satiety. RESULTS: In contrast to lean subjects (p<0.05), PWS and obese subjects were similarly insulin resistant and had similar insulin levels. Ghrelin[total] levels were significantly higher in PWS compared to obese subjects before and during the meal (p<0.05). PYY[3-36] meal responses were higher in PWS than in lean subjects (p=0.01), but not significantly different to obese (p=0.08), with an additional non-significant trend in PYY[total] levels. There were no significant differences in self-reported satiety between groups, however PWS subjects reported more hunger throughout (p=0.003), and exhibited a markedly reduced meal-induced suppression of hunger (p=0.01) compared to lean or obese subjects. CONCLUSIONS: Compared to adiposity-matched control subjects, hyperphagia in PWS is not related to a lower postprandial GLP-1 or PYY response. Elevated ghrelin levels in PWS are consistent with increased hunger and are unrelated to insulin levels.

Prader-Willi syndrome is associated with activation of the innate immune system independently of central adiposity and insulin resistance.

BACKGROUND: Subjects with Prader-Willi syndrome (PWS) have a reduced life expectancy due to cardiovascular disease. Increased systemic low-grade inflammation is postulated as a contributor, despite reported lower visceral fat mass and increased insulin sensitivity. OBJECTIVES: Our aim was to compare inflammatory markers and arterial stiffness in PWS and adiposity-matched obese control subjects. DESIGN: We conducted a cross-sectional cohort study comparing 12 PWS subjects, 12 obese subjects matched for percentage body fat and central abdominal fat mass, and 10 healthy normal-weight subjects. MAIN OUTCOME MEASURES: Dual-energy x-ray absorptiometry was used to assess body composition, flow cytometry to quantify activation markers on immun e cells, and ELISA for measurement of C-reactive protein, adiponectin, and IL-6. Insulin resistance was estimated by homeostasis model assessment and arterial stiffness by applanation tonometry. RESULTS: PWS and obese subjects had similarly increased homeostasis model assessment and arterial stiffness. Nevertheless, PWS subjects showed significantly higher IL-6 (4.9 + or - 1.0 vs. 2.5 + or - 0.4 pg/ml; P = 0.02) and nonsignificantly higher C-reactive protein (10.5 + or - 3.2 vs. 4.0 + or - 1.0 ng/ml; P = 0.08). Neutrophil activation markers CD66b and CD11b were higher in PWS compared to obese subjects (P < 0.01), reflecting an activated innate immune system. These markers were positively related to central adiposity in lean and obese subjects (r = 0.49; P < 0.05), but not in PWS subjects. CONCLUSIONS: PWS subjects compared to adiposity-matched obese subjects demonstrate similar insulin resistance but increased low-grade inflammation. The dissociation of inflammation and central adiposity suggests that activation of innate immunity may be either a specific genetic feature of PWS or linked to the commonly associated obstructive sleep apnea syndrome, and might offer a treatment target to reduce cardiovascular disease.

Short-term overfeeding may induce peripheral insulin resistance without altering subcutaneous adipose tissue macrophages in humans.

OBJECTIVE: Chronic low-grade inflammation is a feature of obesity and is postulated to be causal in the development of insulin resistance and type 2 diabetes. The aim of this study was to assess whether overfeeding induces peripheral insulin resistance in lean and overweight humans, and, if so, whether it is associated with increased systemic and adipose tissue inflammation. RESEARCH DESIGN AND METHODS: Thirty-six healthy individuals undertook 28 days of overfeeding by +1,250 kcal/day (45% fat). Weight, body composition, insulin sensitivity (hyperinsulinemic-euglycemic clamp), serum and gene expression of inflammation markers, immune cell activation, fat cell size, macrophage and T-cell numbers in abdominal subcutaneous adipose tissue (flow cytometry and immunohistochemistry) were assessed at baseline and after 28 days. RESULTS: Subjects gained 2.7 +/- 1.6 kg (P < 0.001) and increased fat mass by 1.1 +/- 1.6% (P < 0.001). Insulin sensitivity decreased by 11% from 54.6 +/- 18.7 to 48.9 +/- 15.7 micromol/(kg of FFM)/min (P = 0.01). There was a significant increase in circulating C-reactive protein (P = 0.002) and monocyte chemoattractant protein-1 (P = 0.01), but no change in interleukin-6 and intercellular adhesion molecule-1. There were no changes in fat cell size, the number of adipose tissue macrophages or T-cells, or inflammatory gene expression and no change in circulating immune cell number or expression of their surface activation markers after overfeeding. CONCLUSIONS: Weight gain-induced insulin resistance was observed in the absence of a significant inflammatory state, suggesting that inflammation in subcutaneous adipose tissue occurs subsequent to peripheral insulin resistance in humans.