Eosinophils protect from metabolic alterations triggered by obesity.

BACKGROUND: Eosinophils are generally related to helminth infections or allergies. Their association with metabolic alterations and adipose tissue (AT) remodeling has been demonstrated mainly in animal models of obesity. However, their physiological role in driving metabolic features has not yet been well described. Herein, we aimed to evaluate the participation of eosinophils in metabolic and adipose tissue homeostasis in mice and humans, focusing on a translational perspective. MATERIAL AND METHODS: Male BALB/c wild-type (WT) mice and GATA-1 knockout (Δdb/GATA-1-/-) mice were followed until 16-week-age in a regular diet or were fed with a high-refined-carbohydrate (HC) diet or high-fat (HF) diet for eight weeks. In subjects with obesity, clinical parameters and omental AT gene expression were evaluated. RESULTS: Eosinophils lack in mice fed a regular diet induced insulin resistance and increased adiposity. Their adipose tissue showed augmented cytokine levels, which could be attributed to increased leukocytes in the tissue, such as neutrophils and pro-inflammatory macrophages. Bone marrow transplant from WT mice to Δdb/GATA-1-/- mice showed some improvement in glucose metabolism with lower adipose tissue mass accretion. Upon an unhealthy diet challenge, Δdb/GATA-1-/- mice fed HC diet showed a mild degree of adiposity and glucose metabolic dysfunction severe in those mice fed HF diet. The expression of eosinophil markers in omental AT from humans with severe obesity was positively correlated to eosinophil cytokines and insulin sensitivity surrogate markers and negatively correlated to systemic insulin, HOMA-IR, and android fat mass. CONCLUSIONS: Eosinophils seem to have a physiological role by controlling systemic and adipose tissue metabolic homeostasis by modulating glucose metabolism, inflammation, and visceral fat expansion, even in lean mice. Indeed, eosinophils also seem to modulate glucose homeostasis in human obesity.

Effect of high-refined carbohydrate diet on intestinal integrity.

OBJECTIVES: One of the leading causes of obesity is the consumption of excess nutrients. Obesity is characterized by adipose tissue expansion, chronic low-grade inflammation, and metabolic alterations. Although consumption of a high-fat diet has been demonstrated to be a diet-induced obesity model associated with gut disorders, the same effect is not well explored in a mild-obesity model induced by high-refined carbohydrate (HC) diet intake. The intestinal tract barrier comprises mucus, epithelial cells, tight junctions, immune cells, and gut microbiota. This system is susceptible to dysfunction by excess dietary components that could increase intestinal permeability and bacterial translocation. The aim of this study was to evaluate whether an HC diet and the alterations resulting from its intake are linked to small intestine changes. METHODS: Male BALB/c mice were fed a chow or an HC diet for 8 wk. RESULTS: Although differences in body weight gain were not observed between the groups, mice fed the HC diet showed increased adiposity associated with metabolic alterations. The interferon-γ expression and myeloperoxidase levels were increased in the small intestine in mice fed an HC diet. However, the intestinal villi length, the expression of tight junctions (zonula occludens-1 and claudin-4) and tumor necrosis factor-α cytokine, and the percentage of intraepithelial lymphocytes did not differ in the jejunum or ileum between the groups. We did not observe differences in intestinal permeability and bacterial translocation. CONCLUSION: Metabolic alterations caused by consumption of an HC diet lead to a mild obesity state that does not necessarily involve significant changes in intestinal integrity.

Indices in dental image exams for bone mineral density evaluation of aromatase inhibitor users.

We evaluated the accuracy of radiomorphometric indices (RI) and fractal dimension (FD) for screening bone mineral density (BMD) in postmenopausal patients who had breast cancer and were using aromatase inhibitors (AI). The sample consisted of 40 participants. Digital panoramic radiography (DPR) and cone beam computed tomography (CBCT) were evaluated along with dual-energy X-ray absorptiometry (DXA), which is the gold standard for detecting low BMD. According to the T-scores of DXA, the subjects were assigned into two groups: with normal BMD and with low BMD (osteopenia and osteoporosis). The area under the curve (AUC), sensitivity, and specificity with their respective confidence intervals were determined for DPR and CBCT. For DPR indices, AUC ranged from 52.6 to 75.8%. The mandibular cortical width (MCW) had the highest AUC. For FD, the total trabecular index had the highest sensitivity, while the index anterior to the mental foramen (MF) had the highest specificity. In CBCT, the AUC ranged from 51.8 to 62.0%. The indices with the highest AUC were the molar (M) and anterior (A). The symphysis (S) index had the highest sensitivity and the posterior (P) index had the highest specificity. Sensitivity and specificity were adequate for the computed tomography index (Inferior; CTI [I]). Therefore, MCW, FD of the mandible angle, and total trabecular ROI in DPR and the CTI (I), M, P, and A indices in CBCT proved to be promising tools in distinguishing individuals with low BMD. Cutoff point for these indices could be a useful tool to investigate low BMD in postmenopausal women taking AI.

Indices in dental image exams for bone mineral density evaluation of aromatase inhibitor users

Abstract We evaluated the accuracy of radiomorphometric indices (RI) and fractal dimension (FD) for screening bone mineral density (BMD) in postmenopausal patients who had breast cancer and were using aromatase inhibitors (AI). The sample consisted of 40 participants. Digital panoramic radiography (DPR) and cone beam computed tomography (CBCT) were evaluated along with dual-energy X-ray absorptiometry (DXA), which is the gold standard for detecting low BMD. According to the T-scores of DXA, the subjects were assigned into two groups: with normal BMD and with low BMD (osteopenia and osteoporosis). The area under the curve (AUC), sensitivity, and specificity with their respective confidence intervals were determined for DPR and CBCT. For DPR indices, AUC ranged from 52.6 to 75.8%. The mandibular cortical width (MCW) had the highest AUC. For FD, the total trabecular index had the highest sensitivity, while the index anterior to the mental foramen (MF) had the highest specificity. In CBCT, the AUC ranged from 51.8 to 62.0%. The indices with the highest AUC were the molar (M) and anterior (A). The symphysis (S) index had the highest sensitivity and the posterior (P) index had the highest specificity. Sensitivity and specificity were adequate for the computed tomography index (Inferior; CTI [I]). Therefore, MCW, FD of the mandible angle, and total trabecular ROI in DPR and the CTI (I), M, P, and A indices in CBCT proved to be promising tools in distinguishing individuals with low BMD. Cutoff point for these indices could be a useful tool to investigate low BMD in postmenopausal women taking AI.

Paradoxical role of tumor necrosis factor on metabolic dysfunction and adipose tissue expansion in mice.

OBJECTIVES: Tumor necrosis factor (TNF) is a well-known cytokine that triggers insulin resistance during obesity development. On the other hand, it is also known that TNF induces a fat mass loss during acute diseases. However, whether TNF has a protective and physiological role to control adipose tissue expansion during obesity still needs to be verified. The aim of this study was to evaluate whether the ablation of TNF receptor 1 (TNFR1) alters fat mass and insulin resistance induced by a highly refined carbohydrate-containing (HC) diet. METHODS: Male C57 BL/6 wild-type (WT) mice and TNFR1 knockout (TNFR1-/-) mice were fed with chow or with the HC diet for 16 wk. RESULTS: TNFR1-/- mice gained more body weight than the WT groups independent of the diet composition. TNFR1-/- mice fed with the chow diet showed higher adiposity, accompanied by higher serum leptin levels. However, these mice showed lower non-esterified fatty acid levels. Furthermore, TNFR1-/- mice had suppressed TNF, interleukin (IL)-6, and IL-10 levels in adipose tissue compared with WT mice. TNFR1-/- mice fed with the HC diet were protected from increased adiposity and glucose intolerance induced by the HC diet and exhibited lower serum resistin levels. CONCLUSIONS: TNF signaling appears to have a paradoxical role on metabolism. Ablation of TNFR1 leads to a reduction of inflammatory cytokines in adipose tissue that is accompanied by higher adiposity in mice fed with chow diet. However, when these mice are given the HC diet, the loss of TNFR1 improves insulin sensitivity and protects mice against additional fat mass.

Two opposite extremes of adiposity similarly reduce inflammatory response of antigen-induced acute joint inflammation.

OBJECTIVE: Acute inflammation is a normal response of tissue to an injury. During this process, inflammatory mediators are produced and metabolic alterations occur. Adipose tissue is metabolically activated, and upon food consumption, it disrupts the inflammatory response. However, little is known about the acute inflammatory response in joints that results from diet-induced adipose tissue remodeling. The objective of this study was to determine whether alterations in adipose tissue mass arising from food consumption modify the inflammatory response of antigen-induced joint inflammation in mice. METHODS: Male BALB/c mice were fed a chow diet, a highly refined carbohydrate-containing (HC) diet for 8 wk. They were then immunized and, after 2 wk, received a knee injection of methylated bovine serum albumin (mBSA). They were sacrificed at 6, 24, and 48 h after injection. The effect of the cafeteria diet for 8 wk, which also increases adipose tissue, or conjugated linoleic acid (CLA) supplementation for 4 wk, a model of lipodystrophy, was evaluated 24 h after knee challenge with mBSA. RESULTS: Cellular influx, predominantly neutrophils, in synovial fluid was attenuated in the HC diet group, as were levels of myeloperoxidase and IL-1ß in periarticular tissue and histopathological analysis. These responses were associated with reduced adiponectin and increased leptin in serum, which was pronounced in mice fed the HC diet. Cafeteria diet and CLA supplementation induced a profile similar to that seen with the HC diet in terms of inflammation, disease response, and metabolic alteration. Interestingly, after the injection of mBSA, the area of adipocytes in the infrapatellar fat pad increased in mice fed with chow diet similar to those fed the HC and cafeteria diet. CONCLUSIONS: We demonstrated that attenuation of joint response induced by diet was independent of adipose tissue remodeling but could be associated with metabolic alterations.

TNF and IL-18 cytokines may regulate liver fat storage under homeostasis conditions.

The inflammation induced by obesogenic diets is associated with deposition of fat in the liver. On the other hand, anti-inflammatory and immunosuppressive therapies may impact in body fat storage and in liver lipid dynamics. It is important to study specific inflammatory mediators in this context, since their role on hepatic damage is not fully clarified. This study aimed to evaluate the role of interleukin (IL)-18 and tumor necrosis factor (TNF) receptor in liver dysfunction induced by diet. Male C57BL/6 wild-type (WT), IL-18, and TNF receptor 1 knockout mice (IL-18-/- and TNFR1-/-) were divided according to the experimental diets: chow diet or a high-refined carbohydrate-containing diet. Alanine aminotransferase was quantified by colorimetric analysis. Total fat content in the liver was determined by Folch methods. Levels of TNF, IL-6, IL-4, and IL-13 in liver samples were measured by ELISA assay. IL-18 and TNFR knockout mice fed with chow diet showed higher liver triglycerides deposition than WT mice fed with the same diet (WT: 131.9 ± 24.5; IL-18-/-: 239.4 ± 38.12*; TNF-/-: 179.6 ± 50.45*; *P < 0.01). Furthermore, these animals also showed a worse liver histopathological score and lower levels of TNF, IL-6, IL-4, and IL-13 in the liver. Interestingly, treatment with a high-carbohydrate diet did not exacerbate liver damage in IL-18-/- and TNFR1-/- mice. Our data suggest that IL-18 and TNF may be involved on hepatic homeostasis mainly in a context of a healthy diet.