Impact of preoperative pasireotide therapy on invasive octreotide-resistant acromegaly.

A 43-year-old woman with an 8-year history of diabetes, hypertension, and dyslipidemia presented with amenorrhea and convulsion. Her MRI scan revealed a 3.5-cm T2-hyperintense pituitary macroadenoma with suprasellar extension to the frontal lobe and bilateral cavernous sinus invasion. Her serum levels of GH and insulin-like growth factor-I (IGF-I) were elevated to 9.08 ng/mL (normal range: <2.1 ng/mL) and 1,000 ng/mL (normal range: 90-233 ng/mL, SD score +10.6), respectively. Bromocriptine insufficiently suppressed her GH levels, while octreotide paradoxically increased her GH levels. Together with her characteristic features, she was diagnosed with acromegaly caused by an invasive GH-producing pituitary macroadenoma. As performing a one-stage operation would have been extremely difficult, she was first treated with pasireotide long-acting release (40 mg monthly) for 5 months followed by a successful transsphenoidal surgery. One month after the first injection, biochemical control was achieved (IGF-I, 220 ng/mL; GH, 1.26 ng/mL), and tumor shrinkage of approximately 50% was observed. The resected tumor was histologically diagnosed as a sparsely granulated somatotroph adenoma, with higher expression of somatostatin receptor subtype 5 (SSTR5) than that of SSTR2A. The germline aryl hydrocarbon receptor interacting protein (AIP) mutation was negative, and several tumor cells were weakly immunoreactive for AIP. Despite the presence of a residual tumor postoperatively, biochemical control was achieved 6 months after the final injection of pasireotide. In conclusion, this case suggests that pasireotide may be an option for preoperative first-line therapy in invasive and octreotide-resistant sparsely granulated somatotroph adenomas.

cAMP ameliorates inflammation by modulation of macrophage receptor for advanced glycation end-products.

Clarification of the roles of PAMPs (pathogen-associated molecular patterns) and DAMPs (damage-associated molecular patterns) is indispensable for therapeutic strategies against various inflammatory diseases. RAGE (receptor for advanced glycation end-products) is one of the PRRs (pattern recognition receptors) and has been implicated in autoimmune and inflammatory diseases. Effective remedies targeting RAGE are required for the diseases. In the present study, we show that cAMP-induced modulation of the RAGE isoform in macrophages can control the inflammatory state in both in vitro and in vivo experimental conditions. The RAGE ligand S100B stimulated MCP-1 (monocyte chemoattractant protein-1) secretion from peritoneal macrophages, but cAMP elevation suppressed it by converting the RAGE isoform from a membrane-bound into a soluble form. This shedding is the result of ectodomain cleavage of mRAGE (membrane-bound RAGE) by MMP9 (matrix metalloproteinase 9). Furthermore, forskolin significantly inhibited peritoneal macrophage accumulation in a mouse S100B-induced peritonitis model. These results suggest that cAMP serves as a negative regulator of ligand-RAGE signalling and macrophage recruitment by mRAGE down-regulation and formation of decoys as soluble receptors. The present study should deepen our understanding of the pathogenesis of RAGE-mediated tissue derangement and provide new clues for overcoming RAGE-related inflammatory diseases.

p62-mediated autophagy affects nutrition-dependent insulin receptor substrate 1 dynamics in 3T3-L1 preadipocytes.

AIMS/INTRODUCTION: Previous studies have shown that an organism's nutritional status changes the protein levels of insulin receptor substrate 1 (IRS-1) in a tissue-specific manner. Although the mechanisms underlying the regulation of IRS-1 in the nutrient-rich conditions associated with diabetes and insulin resistance have been well studied, those under nutrient-poor conditions remain unknown. The aim of the present study was to investigate how IRS-1 protein levels change depending on the nutritional status of 3T3-L1 preadipocytes. MATERIALS AND METHODS: 3T3-L1 preadipocytes were treated with glucose-, amino acid- and serum-free medium for starvation. IRS-1 protein levels were detected by western blot. Autophagy activity was observed by western blot and fluorescence microscopy. The effect of autophagy and p62, an adaptor for selective autophagy, on IRS-1 protein levels under starvation conditions was examined by western blot and immunocytochemistry. RESULTS: We showed that the levels of IRS-1, but not those of insulin receptor and protein kinase B, decreased when starvation activated autophagy. The inhibition of autophagy by chloroquine or autophagy-related 7 (Atg7) ribonucleic acid interference counteracted the starvation-induced decrease of IRS-1. Additionally, Atg7 knockdown increased insulin-stimulated phosphorylation of protein kinase B under starvation conditions. Furthermore, p62 colocalized with IRS-1 under starvation conditions, and p62 knockdown counteracted the starvation-induced degradation of IRS-1. CONCLUSIONS: Autophagy through p62 plays an important role in regulating IRS-1 protein levels in response to nutritional deficiency. The present findings suggest that autophagy might function as energy depletion-sensing machinery that finely tunes insulin signal transduction.

Inhibin ßE (INHBE) is a possible insulin resistance-associated hepatokine identified by comprehensive gene expression analysis in human liver biopsy samples.

The liver plays a major role in whole-body energy homeostasis by releasing secretory factors, termed hepatokines. To identify novel target genes associated with insulin resistance, we performed a comprehensive analysis of gene expression profiles using a DNA chip method in liver biopsy samples from humans with varying degrees of insulin resistance. Inhibin ßE (INHBE) was identified as a novel putative hepatokine with hepatic gene expression that positively correlated with insulin resistance and body mass index in humans. Quantitative real time-PCR analysis also showed an increase in INHBE gene expression in independent liver samples from insulin-resistant human subjects. Additionally, Inhbe gene expression increased in the livers of db/db mice, a rodent model of type 2 diabetes. To preliminarily screen the role of Inhbe in vivo in whole-body energy metabolic status, hepatic mRNA was knocked down with siRNA for Inhbe (siINHBE) in db/db mice. Treatment with siINHBE suppressed body weight gain during the two-week experimental period, which was attributable to diminished fat rather than lean mass. Additionally, treatment with siINHBE decreased the respiratory quotient and increased plasma total ketone bodies compared with treatment with non-targeting siRNA, both of which suggest enhanced whole-body fat utilization. Our study suggests that INHBE functions as a possible hepatokine to alter the whole-body metabolic status under obese insulin-resistant conditions.