Diet-Induced Inflammation of the Hypothalamus in Obesity

Velloso, Lı́cio A.; Araújo, Eliana P.; Souza, Cláudio Teodoro de

doi:10.1159/000153423

Cited by 119 publications

(92 citation statements)

References 60 publications

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“…From these data, we conclude that changes in gut microbiota and changes in gut permeability could be signaled directly to the brain via the vagus nerve and that chronic exposure to low-level LPS could lead to the development of leptin resistance in VAN. It is unclear whether LPS could induce leptin resistance in the arcuate nucleus. There is evidence that proinflammatory signals in the hypothalamus result in impaired leptin signaling (35) and that NF-B signaling, an important downstream effector of LPS, induces SOCS-3 expression in the arcuate nucleus (37). Our data shed no light on the matter and suggest only that LPS levels are insufficient following 8 wk ingestion of a HF diet in Sprague-Dawley rats to effect leptin signaling in the arcuate nucleus.…”

Section: Discussionmentioning

confidence: 59%

Diet-induced obesity leads to the development of leptin resistance in vagal afferent neurons

Lartigue

Serre

Espero

et al. 2011

American Journal of Physiology-Endocrinology and Metabolism

152

142

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de Lartigue G, Barbier de la Serre C, Espero E, Lee J, Raybould HE. Diet-induced obesity leads to the development of leptin resistance in vagal afferent neurons. Am J Physiol Endocrinol Metab 301: E187-E195, 2011. First published April 26, 2011; doi:10.1152/ajpendo.00056.2011.-Ingestion of high-fat, high-calorie diets is associated with hyperphagia, increased body fat, and obesity. The mechanisms responsible are currently unclear; however, altered leptin signaling may be an important factor. Vagal afferent neurons (VAN) integrate signals from the gut in response to ingestion of nutrients and express leptin receptors. Therefore, we tested the hypothesis that leptin resistance occurs in VAN in response to a high-fat diet. Sprague-Dawley rats, which exhibit a bimodal distribution of body weight gain, were used after ingestion of a high-fat diet for 8 wk. Body weight, food intake, and plasma leptin levels were measured. Leptin signaling was determined by immunohistochemical localization of phosphorylated STAT3 (pSTAT3) in cultured VAN and by quantifaction of pSTAT3 protein levels by Western blot analysis in nodose ganglia and arcuate nucleus in vivo. To determine the mechanism of leptin resistance in nodose ganglia, cultured VAN were stimulated with leptin alone or with lipopolysaccharide (LPS) and SOCS-3 expression measured. SOCS-3 protein levels in VAN were measured by Western blot following leptin administration in vivo. Leptin resulted in appearance of pSTAT3 in VAN of low-fat-fed rats and rats resistant to diet-induced obesity but not diet-induced obese (DIO) rats. However, leptin signaling was normal in arcuate neurons. SOCS-3 expression was increased in VAN of DIO rats. In cultured VAN, LPS increased SOCS-3 expression and inhibited leptin-induced pSTAT3 in vivo. We conclude that VAN of diet-induced obese rats become leptin resistant; LPS and SOCS-3 may play a role in the development of leptin resistance.lipopolysaccharide; high-fat diet; suppressor of cytokine signaling-3 THE GUT PLAYS A CRUCIAL ROLE in sensing luminal contents that is important for the efficient digestion and absorption of ingested nutrients but also in integration of other physiological processes that regulate metabolism and energy expenditure, such as pancreatic ␤-cell function, hepatic function, and also food intake (34). In response to the presence or absence of food, enteroendocrine cells of the gut release anorexic or orexigenic hormones, respectively. The first site of integration of these signals occurs at the level of vagal afferent neurons (VAN), which project to and stimulate second-order neurons in the dorsal vagal complex of the hindbrain (27). VAN express receptors for many of the anorexigenic and orexigenic hormones released from the gut wall and mediate changes in gastrointestinal function and food intake in response to luminal nutrients (18).Leptin is a gut and adipose tissue-derived hormone that regulates a range of biological functions and processes, including energy intake and expenditure, body fat, neuroendocrine systems...

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Section: Discussionmentioning

confidence: 59%

Diet-induced obesity leads to the development of leptin resistance in vagal afferent neurons

Lartigue

Serre

Espero

et al. 2011

American Journal of Physiology-Endocrinology and Metabolism

152

142

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“…In this regard, a dysfunction of neural regulatory systems such as leptin resistance, which is also associated to type 2 diabetes, has been closely linked with local inflammation (Velloso et al, 2008).…”

Section: Environmental Influencementioning

confidence: 99%

Dietary factors, epigenetic modifications and obesity outcomes: Progresses and perspectives

Milagro

Mansego

Miguel

et al. 2013

Molecular Aspects of Medicine

251

161

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Nutritional factors play a life-long role in human health. Indeed, there is growing evidence that one of the mechanisms by which nutrients and bioactive compounds affect metabolic traits is epigenetics. Complex interactions among food components and histone modifications, DNA methylation, non-coding RNA expression and chromatin remodeling factors lead to a dynamic regulation of gene expression that controls the cellular phenotype. Although perinatal period is the time of highest phenotypic plasticity, contributing largely to developmental programming, also during adulthood there is evidence about a nutritional influence on epigenetic regulation. Similarly to type 2 diabetes, hypertension, atherosclerosis and other metabolic disorders, obesity predisposition and weight loss outcomes have been repeatedly associated to changes in epigenetic patterns. Different non-nutritional risk factors that usually accompany obesity seem also to be involved in these epigenetic modifications, especially hyperglycemia, inflammation, hypoxia and oxidative stress. There are currently three major objectives in epigenetic research in relation to obesity: to search for epigenetic biomarkers to predict future health problems or detect the individuals at most risk, to understand the obesity-related environmental factors that could modulate gene expression by affecting epigenetic mechanisms, and to study novel therapeutic strategies based on nutritional or pharmacological agents that can modify epigenetic marks. At this level, the major tasks are: development of robust epigenetic biomarkers of weight regulation, description of those epigenetic marks more susceptible to be modified by dietary exposures, identification of the active ingredients (and the doses) that alter the epigenome, assessment of the real importance of other obesity-related factors on epigenetic regulation, determination of the period of life in which best results are obtained, and understanding of the importance of the inheritance of these epigenetic marks.

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“…Concomitantly, there is death of single adipocytes and secretion of pro-inflammatory cytokines, chemokines and other adipokines from immune cells and/or adipocytes [55] that contributes to further recruitment of macrophages and adipositis. Other associated changes are ectopic fat deposition in several organs, including beta cells, endoplasmic reticulum stress, compromised fatty acid oxidation, increased levels of circulating non-esterified fatty acids and other lipids [24] and as observed in mice, dysfunction of neural regulatory systems such as leptin resistance, again closely linked with local inflammation [56]. The intimate relationship between visceral obesity and inflammation is underscored by findings that weight reduction causes downregulation of inflammation in visceral fat as well as in the circulation [57,58].…”

Section: Excess Nutrients/obesitymentioning

confidence: 99%

The global diabetes epidemic as a consequence of lifestyle-induced low-grade inflammation

Kolb¹,

2009

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The recent major increase in the global incidence of type 2 diabetes suggests that most cases of this disease are caused by changes in environment and lifestyle. All major risk factors for type 2 diabetes (overnutrition, low dietary fibre, sedentary lifestyle, sleep deprivation and depression) have been found to induce local or systemic low-grade inflammation that is usually transient or milder in individuals not at risk for type 2 diabetes. By contrast, inflammatory responses to lifestyle factors are more pronounced and prolonged in individuals at risk of type 2 diabetes and appear to occur also in the pancreatic islets. Chronic low-grade inflammation will eventually lead to overt diabetes if counter-regulatory circuits to inflammation and metabolic stress are compromised because of a genetic and/or epigenetic predisposition. Hence, it is not the lifestyle change per se but a deficient counter-regulatory response in predisposed individuals which is crucial to disease pathogenesis. Novel approaches of intervention may target these deficient defence mechanisms.

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Diet-Induced Inflammation of the Hypothalamus in Obesity

Cited by 119 publications

References 60 publications

Diet-induced obesity leads to the development of leptin resistance in vagal afferent neurons

Diet-induced obesity leads to the development of leptin resistance in vagal afferent neurons

Dietary factors, epigenetic modifications and obesity outcomes: Progresses and perspectives

The global diabetes epidemic as a consequence of lifestyle-induced low-grade inflammation

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