Central administration of interleukin-4 exacerbates hypothalamic inflammation and weight gain during high-fat feeding.

In peripheral tissues, the link between obesity and insulin resistance involves low-grade inflammation induced by macrophage activation and proinflammatory cytokine signaling. Since proinflammatory cytokines are also induced in the hypothalamus of animals placed on a high-fat (HF) diet and can inhibit neuronal signal transduction pathways required for normal energy homeostasis, hypothalamic inflammation is hypothesized to contribute to the pathogenesis of diet-induced obesity (DIO). We addressed this hypothesis by perturbing the inflammatory milieu of the hypothalamus in adult male Wistar rats using intracerebroventricular (icv) administration of interleukin-4 (IL-4), a Th2 cytokine that promotes alternative activation (M2) of macrophages and microglia. During HF feeding, icv IL-4 administration increased hypothalamic proinflammatory cytokine gene expression and caused excess weight gain. Intracerebroventricular pretreatment with PS1145, an inhibitor of IKKbeta (a key intracellular mediator of inflammatory signaling), blocked both IL-4 effects, suggesting a causal relationship between IL-4-induced weight gain and hypothalamic inflammation. These observations add to growing evidence linking hypothalamic inflammation to obesity pathogenesis.

Prolonged intrahepatic cholestasis after exposure to loxoprofen.

OBJECTIVE: The objective of this report was to describe a case of prolonged intrahepatic cholestasis likely associated with the use of loxoprofen, a phenylpropionate NSAID. METHODS: A 36-year-old female patient was transferred to Gunma University Hospital, Maebashi, Japan, with progressive pruritus and jaundice that developed after 5-day treatment with 120 mg/d of loxoprofen (maximum recommended dose, 180 mg/d) for menstrual pain. Liver function tests found the following concentrations: total bilirubin, 27.5 mg/dL (normal [nl] range, 0.3-1.2 mg/dL); aspartate aminotransferase, 151 IU/L (nl, 13-33 IU/L); alkaine aminotransferase, 470 IU/L (nl, 8-42 IU/L); alkaline phosphatase, 1082 IU/L (n1, 115-359 IUAL); and gamma-glutamyl transpeptidase, 795 IU/L (nl, 10-47 IU/L) indicative of intrahepatic cholestasis. No use of alcohol or other drugs or herbal products was reported. The patient had a history of elevated hepatic enzymes of unknown origin following the use of mefenamic acid. The patient was prescribed ursodeoxycholic acid 3 weeks after the onset of symptoms of intrahepatic cholestasis. Thereafter, due to progressive cholestasis, an IV pulse of methylprednisolone (1000 mg/d) and the herbal product Inchin-ko-to (TJ-135) were administered. Plasma bilirubin adsorption (PA) and plasma exchange (PE) were performed. RESULTS: Following treatment with PA and PE for 3 weeks with administration of methylprednisolone and Inchin-ko-to, signs and symptoms of intrahepatic cholestasis began to resolve (3.5 months after the onset); they were completely resolved 8 months after the initial episode. A Naranjo scale score of 6 suggested that loxoprofen was likely the cause of the prolonged cholestasis in this patient. CONCLUSION: Based on the Naranjo score, this case of prolonged intrahepatic cholestasis in a young woman was likely associated with loxoprofen use.

Identification of nesfatin-1 as a satiety molecule in the hypothalamus.

The brain hypothalamus contains certain secreted molecules that are important in regulating feeding behaviour. Here we show that nesfatin, corresponding to NEFA/nucleobindin2 (NUCB2), a secreted protein of unknown function, is expressed in the appetite-control hypothalamic nuclei in rats. Intracerebroventricular (i.c.v.) injection of NUCB2 reduces feeding. Rat cerebrospinal fluid contains nesfatin-1, an amino-terminal fragment derived from NUCB2, and its expression is decreased in the hypothalamic paraventricular nucleus under starved conditions. I.c.v. injection of nesfatin-1 decreases food intake in a dose-dependent manner, whereas injection of an antibody neutralizing nesfatin-1 stimulates appetite. In contrast, i.c.v. injection of other possible fragments processed from NUCB2 does not promote satiety, and conversion of NUCB2 to nesfatin-1 is necessary to induce feeding suppression. Chronic i.c.v. injection of nesfatin-1 reduces body weight, whereas rats gain body weight after chronic i.c.v. injection of antisense morpholino oligonucleotide against the gene encoding NUCB2. Nesfatin-1-induced anorexia occurs in Zucker rats with a leptin receptor mutation, and an anti-nesfatin-1 antibody does not block leptin-induced anorexia. In contrast, central injection of alpha-melanocyte-stimulating hormone elevates NUCB2 gene expression in the paraventricular nucleus, and satiety by nesfatin-1 is abolished by an antagonist of the melanocortin-3/4 receptor. We identify nesfatin-1 as a satiety molecule that is associated with melanocortin signalling in the hypothalamus.

Molecular mechanisms associated with leptin resistance: n-3 polyunsaturated fatty acids induce alterations in the tight junction of the brain.

High-fat diets cause peripheral leptin resistance, and dietary lipid composition affects sensitivity to leptin. We examined the role of n-3 polyunsaturated fatty acid (PUFA) in peripheral leptin resistance. Dietary PUFAs (0.4% wt/wt) caused insensitivity to peripherally but not intracerebroventricularly administered leptin. n-3 PUFA increased body weight, associated with a significant reduction of leptin concentration in the cerebrospinal fluid. Dietary n-3 PUFA reduced transport of endogenous or exogenously administered leptin into the brain, associated with increased expression of hypothalamic occludin, but caused no change in expression of leptin receptors, proteins associated with leptin signaling or other tight junction proteins. Continuous intracerebroventricular infusion of an antisense morpholino oligonucleotide targeted to occludin mRNA reversed n-3 PUFA-induced insensitivity to peripherally administered leptin. We conclude that n-3 PUFA induces peripheral leptin resistance via an increase in the expression of hypothalamic occludin, reducing paracellular transport of leptin into the brain.