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Carcinoid tumors derived from neuroendocrine cells can release serotonin and other vasoactive substances into the systemic circulation, resulting in carcinoid syndrome. Testicular carcinoid, a rare disease accounting for less than 1% of all testicular neoplasms, rarely manifests symptoms of carcinoid syndrome. We describe a case of carcinoid syndrome arising from a primary testicular carcinoid tumor. A 21-year-old male patient presented with facial flushing and diarrhea for 5 years. He had an enlarged left testis and a 1-cm, ill-defined, hard, non-tender mass in his right testis. His 24 h urinary excretion of 5-hydroxyindoleacetic acid was elevated (16.1 mg/day). Somatostatin receptor scintigraphy correlated with carcinoid tumor in both testes. Following bilateral orchiectomy, the patient's facial flushing and diarrhea disappeared.

Ghrelin, a stomach-derived hormone, induces adiposity when administered to rodents. Because ghrelin receptor is abundantly expressed in adipose tissue, we investigated the role of ghrelin in adipocyte biology. We observed ghrelin receptor expression in 3T3-L1 preadipocytes and adipocytes. Treatment of preadipocytes with ghrelin induced cellular proliferation and differentiation to mature adipocytes, as well as basal and insulin-stimulated glucose transport, but it inhibited adipocyte apoptosis induced by serum deprivation. Exposure of 3T3-L1 cells to ghrelin caused a rapid activation of MAPKs, especially ERK1/2. Chemical inhibition of MAPK blocked the mitogenic and antiapoptotic effects of ghrelin. Ghrelin also stimulated the insulin receptor substrate-associated phosphatidylinositol 3-kinase/Akt pathway in 3T3-L1 preadipocytes and adipocytes, whereas inhibition of this pathway blocked the effects of ghrelin on cell proliferation, antiapoptosis and glucose uptake. These findings suggest that the direct effects of ghrelin on proliferation, differentiation, and apoptosis in adipocytes may play a role in regulating fat cell number. These effects may be mediated via activation of the MAPK and phosphatidylinositol 3-kinase/Akt pathways.

The 5-year incidence of coronary artery disease (CAD) and progression to overt proteinuria was investigated in patients with type 2 diabetes mellitus who had microalbuminuria with (MA+R group, n=93) or without (MA-R group, n=138) diabetic retinopathy. The rate of progression to overt proteinuria was higher in the MA+R group than in the MA-R group. The MA-R group had more components of metabolic syndrome than the MA+R and normoalbuminuric (NA, n=205) groups. The MA-R group had a higher 5-year incidence of CAD than the NA group. The incidence of CAD tended to be higher in the MA-R group than in the MA+R group, but statistical significance was not reached. The present study shows that patients with diabetic retinopathy and microalbuminuria represent a group with incipient diabetic nephropathy having higher risk for progression to overt proteinuria. On the other hand, patients with microalbuminuria and no retinopathy may represent a group with characteristics of metabolic syndrome.

Background: Oxidative stress may play an important role in the pathogenesis of bronchial asthma., Objective: We evaluated the therapeutic effect of alpha-lipoic acid, a nonenzymatic antioxidant, in a mouse model of asthma., Methods: BALB/c mice were immunized intraperitoneally with ovalbumin (OVA) on days 1 and 14 and challenged with inhaled OVA on days 28, 29, and 30. Mice were fed OVA-free standard mouse chow with 0%, 0.125%, 0.25%, 0.5%, and 1% (wt/wt) alpha-lipoic acid during the immunization and challenge periods. On day 31, mice were challenged with inhaled methacholine, and enhanced pause was measured as an index of airway hyperresponsiveness. Severity of airway inflammation was determined by means of differential cell count of bronchoalveolar lavage (BAL) fluid and by means of histopathologic lung analysis. Levels of OVA-specific IgE in serum, IL-4 and IL-5 in BAL fluid, and intracellular reactive oxygen species in alveolar macrophages and lymphocytes obtained from regional perihilar lymph nodes were measured. Nuclear factor kappaB DNA-binding activity in lung tissues was analyzed by means of electrophoretic gel mobility shift assay., Results: Compared with untreated asthmatic mice, mice treated with alpha-lipoic acid had significantly reduced airway hyperresponsiveness, a lower proportion of eosinophils among BAL cells, and significantly improved pathologic lesion scores of the lungs. alpha-Lipoic acid also significantly reduced serum OVA-specific IgE concentrations, IL-4 and IL-5 concentrations in BAL fluid, and intracellular reactive oxygen species and nuclear factor kappaB DNA-binding activity., Conclusion: These results suggest that oxidative stress plays an important role in asthmatic airway inflammation and that alpha-lipoic acid may be useful as adjuvant therapy for bronchial asthma.

AMP-activated protein kinase (AMPK) functions as a fuel sensor in the cell and is activated when cellular energy is depleted. Here we report that alpha-lipoic acid (alpha-LA), a cofactor of mitochondrial enzymes, decreases hypothalamic AMPK activity and causes profound weight loss in rodents by reducing food intake and enhancing energy expenditure. Activation of hypothalamic AMPK reverses the effects of alpha-LA on food intake and energy expenditure. Intracerebroventricular (i.c.v.) administration of glucose decreases hypothalamic AMPK activity, whereas inhibition of intracellular glucose utilization through the administration of 2-deoxyglucose increases hypothalamic AMPK activity and food intake. The 2-deoxyglucose-induced hyperphagia is reversed by inhibiting hypothalamic AMPK. Our findings indicate that hypothalamic AMPK is important in the central regulation of food intake and energy expenditure and that alpha-LA exerts anti-obesity effects by suppressing hypothalamic AMPK activity.

Objective: Uncoupling protein 2 (UCP2) belongs to the mitochondrial anion carrier family and regulates production of reactive oxygen species in macrophages. Previous studies have shown that selective genetic disruption of UCP2 in bone marrow cells results in excess accumulation of monocytes/macrophages in the vascular wall of hypercholesterolemic low-density lipoprotein receptor-deficient (LDLR-/-) mice. Here we investigated whether UCP2 regulates expression of genes involved in monocyte recruitment., Methods and Results: UCP2 overexpression in THP1 monocytes, which induced a 10-fold increase in mitochondrial UCP2 protein levels, reduced steady-state level of intracellular reactive oxygen species (ROS) and H2O2-induced ROS production. THP1 monocytes with UCP2 overexpression showed lower intracellular calcium levels and less H2O2-triggered intracellular calcium mobilization, and less protein and mRNA levels of beta2 integrins, most notably CD11b. UCP2 overexpression reduced beta2 integrin-mediated firm adhesion of monocytes to either tumor necrosis factor-alpha (TNF-alpha)-stimulated human aortic endothelial cell (HAEC) monolayers or to plates coated with intercellular adhesion molecule-1, not vascular cell adhesion molecule-1. UCP2 overexpression also inhibited cell spreading and actin polymerization in monocytes treated with TNF-alpha and monocyte chemoattractant protein-1 (MCP-1), and reduced MCP-1-induced transmigration of monocytes through HAEC monolayers., Conclusions: Mitochondrial UCP2 in circulating monocytes may prevent excessive accumulation of monocytes/macrophages in the arterial wall, thereby reducing atherosclerotic plaque formation.

Signaling molecules that bind to chemokine receptors should play key roles in regulation of cell migration induced by chemokines. To characterize the CCR1-mediated cellular signal transduction mechanism, we used the yeast two-hybrid system to identify a cellular ligand for CCR1. LZIP, which has been known as a transcription factor in various cell types, was identified as a CCR1 binding protein. Although the ability of LZIP to bind DNA is possibly what allows it to function as a transcription factor, its detailed function and participation in chemotaxis have not been established. We found that LZIP binds to CCR1 based on results of a mammalian two-hybrid assay and immunoprecipitation experiments. The 21-260 residues of LZIP were essential for interaction with CCR1. Results from a chemotaxis assay using LZIP transfected cells showed that LZIP enhanced Lkn-1-induced chemotaxis, whereas the chemotactic activities induced by other CC chemokines that bind to CCR1, including MIP-1alpha, RANTES, or HCC-4, were not affected by LZIP overexpression. These data indicate that LZIP binds to CCR1 and that the interaction between CCR1 and LZIP participates in regulation of Lkn-1-dependent cell migration without affecting the chemotactic activities of other CC chemokines that bind to CCR1.

Background: Glomerular endothelial cells play a role in the pathogenesis of glomerulonephritis by producing chemotactic factors. We investigated the role of NF-kappa B and AP-1 in tumour necrosis factor alpha (TNF-alpha) induced monocyte chemoattractant protein 1 (MCP-1) production in cultured human glomerular endothelial cells (HGEC). We also examined whether or not these processes could be modified by glucocorticoid., Methods: MCP-1 protein and mRNA levels were measured by ELISA and northern blot. NF-kappa B and AP-1 binding activity were assessed by electrophoretic mobility shift assay. Cytosolic I kappa B alpha and nuclear p65 protein were evaluated by western blot. For specific inhibition of NF-kappa B or AP-1, we used a decoy oligodeoxynucleotide., Results: TNF-alpha (10 ng/ml) increased MCP-1 mRNA expression in HGEC and also the release of MCP-1 protein into culture media. These effects could be partially inhibited by dexamethasone (10 nM). TNF-alpha induced MCP-1 production appeared to be NF-kappa B and AP-1 interdependent, based on the following results. (i) TNF-alpha increased NF-kappa B and AP-1 binding activity. (ii) Both NF-kappa B decoy oligodeoxynucleotide and AP-1 decoy oligodeoxynucleotide partially suppressed TNF-alpha induced MCP-1 mRNA expression. On the other hand, dexamethasone decreased TNF-alpha induced DNA-binding activity of AP-1 without an effect on the DNA-binding activity of NF-kappa B, cytosolic I kappa B alpha degradation or p65 nuclear translocation., Conclusions: These data demonstrate that while TNF-alpha induced MCP-1 production is mediated by the cooperative action of NF-kappa B and AP-1 in HGEC, dexamethasone represses TNF-alpha induced MCP-1 production via suppression of AP-1 binding activity.

The intracellular triglyceride content in skeletal muscle is increased in insulin-resistant states such as obesity or high-fat feeding. It has been hypothesized that increased fatty acid oxidation resulting from increased lipolysis of intramyocellular triglycerides may be responsible for this insulin resistance. This study was undertaken to examine whether insulin resistance is associated with increased lipolysis in skeletal muscle in rats fed a high-fat diet. Sprague-Dawley rats were fed a high-fat diet for 5 weeks. Lipolysis in skeletal muscle and adipose tissue was determined by measuring the interstitial glycerol concentrations using a microdialysis method in basal and hyperinsulinemic-euglycemic clamp conditions. In the basal state, plasma free fatty acid (FFA) levels were higher in high-fat-fed rats than in low fat-fed rats (P <.05). In contrast, plasma glycerol levels (P <.001) and interstitial glycerol concentrations of skeletal muscle (P <.05) and adipose tissue (P <.01) were lower in high fat-fed rats than in low fat-fed rats. Plasma (P <.05) and interstitial glycerol concentrations (P <.05 for skeletal muscle, P <.01 for adipose tissue) during the hyperinsulinemic euglycemic clamps were also lower in the high-fat diet group. These results do not support the idea that increased fatty acid oxidation resulting from increased lipolysis of intramyocellular triglycerides is responsible for the insulin resistance in high fat-fed rats.

Objectives: Small dense LDL, low density lipoprotein (LDL) particles with small size and high density, is regarded as a significant risk factor for cardiovascular diseases. Diabetes mellitus is one of the conditions accompanied by increased small dense LDL. We analyzed LDL subclass in type 2 diabetics and normal controls with LipoPrint LDL System to investigate the LDL heterogeneity in diabetics and factors affecting it., Design and Methods: We selected 40 normal controls and 40 type 2 diabetics with fasting blood glucose level over 7.0 mmol/L and HbA1c level over 7%. LDL subclass was determined with LipoPrint LDL System. LipoPrint LDL System fractionates LDL into seven parts (LDL1-7) by size and LDL3 to LDL7 are defined as small-sized LDL. In addition we estimated 'the percent of small-sized LDL over whole LDL' and defined it as 'small-sized LDL proportion'., Results: Mean small-sized LDL proportion was significantly higher in diabetics (23.4%) than in controls (11.8%) (p<0.001) and small-sized LDL proportion showed positive correlation with blood levels of glucose, HbA1c, total cholesterol, triglyceride, and oxidized LDL and negative correlation with HDL cholesterol level in univariate analysis (p<0.001). Of these parameters, triglyceride, HbA1c, oxidized LDL were statistically significant variables contributing to the small-sized LDL proportion in stepwise multiple regression analysis., Conclusions: We analyzed small-sized LDL proportion in type 2 diabetics and found that it was significantly increased in diabetics than control subjects and it was independently correlated with triglyceride, HbA1c, oxidized LDL in descending order, which are reflecting lipid metabolism, glycation, and oxidative stress, respectively.

Lipid accumulation in nonadipose tissues is closely related to the development of type 2 diabetes in obese subjects. We examined the potential preventive effect of peroxisome proliferator-activated receptor (PPAR)-alpha and PPAR-gamma stimulation on the development of diabetes in obese diabetes-prone OLETF rats. Chronic administration of a PPAR-alpha agonist (0.5% [wt/wt] fenofibrate) or a PPAR-gamma agonist (3 mg x kg(-1) x day(-1) rosiglitazone) completely prevented the development of glycosuria. Pancreatic islets from untreated OLETF rats underwent sequential hypertrophy and atrophy, which was completely prevented by chronic fenofibrate treatment. In contrast, rosiglitazone treatment did not affect islet hypertrophy at earlier stages but prevented beta-cell atrophy at later stages. Fenofibrate treatment decreased body weight and visceral fat, whereas rosiglitazone treatment increased body weight. Despite the opposite effects on adiposity, both drugs were equally effective in improving insulin actions in skeletal muscle. Furthermore, both drugs significantly decreased the triglyceride content in the soleus muscle and pancreatic islets. The present study demonstrates that the PPAR-alpha agonist fenofibrate prevents the development of diabetes in OLETF rats by reducing adiposity, improving peripheral insulin action, and exerting beneficial effects on pancreatic beta-cells.

This study investigated the effect of oleic acid on the expression levels of endothelin-1 (ET-1) and on the signaling pathways mediating it in human aortic endothelial cells (HAECs). ET-1 mRNA expression was significantly increased by oleic acid in a dose- and time-dependent manner. Elevation of ET-1 expression in response to oleic acid was inhibited by the protein kinase C (PKC) inhibitor, GF109203X, or the NF-kappa B inhibitor, pyrrolidine dithiocarbamate. In addition, both PKC and NF-kappa B activities were significantly increased by oleic acid. Immunoblot analysis revealed that conventional PKCs (PKC-alpha and -beta II isoforms) were significantly increased in the membranous fractions of HAECs treated with oleic acid. PKC inhibitor completely abolished oleic acid-induced NF-kappa B activation, suggesting that PKC activation is upstream of NF-kappa B activation in oleic acid-induced ET-1 expression. These data suggest that elevated plasma oleic acid levels observed in obese, insulin-resistant subjects result in endothelial dysfunction, at least in part, through an increase in ET-1 expression.

We found that UCP-1 and UCP-3 mRNA expression levels and the UCP-1 protein content in brown adipose tissue (BAT) were reduced in prediabetic OLETF rats than the lean LETO rats. Administration of dehydroepiandrosterone (DHEA) for 17 days induced remarkable weight loss, which was in part attributed to an enhanced utilization of ingested energy. DHEA administration significantly increased the levels of BAT UCP-1 and UCP-3 mRNA expression. Among the upstream signals for UCP-1 regulation, expression levels of the beta 3 adrenergic receptor (beta(3)AR) and PPAR gamma coactivator-1 (PGC-1) were significantly decreased in the OLETF rats and increased by DHEA administration. The decreased expression levels of UCP-1 and its upstream regulators, beta(3)AR and PGC-1, in BAT may contribute to inefficient energy utilization and obesity in OLETF rats, which was corrected by DHEA treatment.

Increased expression of endothelin-1 (ET-1) is associated with diabetic retinopathy and vasculopathy, although the molecular explanation has not been defined. The effects of high glucose and protein kinase C (PKC) activation on platelet-derived growth factor (PDGF)-BB and of ET-1 expression in the retina of streptozotocin (STZ)-induced diabetic rats and bovine retinal pericytes (BRPC) were examined. In 4-week diabetic rats, PDGF-B and prepro-ET-1 (ppET-1) mRNA levels increased significantly by 2.8- and 1.9-fold, respectively, as quantified by RT-PCR. Treatment with PKC-beta isoform-specific inhibitor (LY333531) or insulin normalized retinal ET-1 and PDGF-B expression. In BRPC, high glucose levels increased ppET-1 and PDGF-B mRNA expression by 1.7- and 1.9-fold, respectively. The addition of PDGF-BB but not PDGF-AA increased expression of ppET-1 and vascular endothelial growth factor mRNA by 1.6- and 2.1-fold, respectively, with both inhibited by AG1296, a selective PDGF receptor kinase inhibitor. A general PKC inhibitor, GF109203X, suppressed PDGF-BB's induction of ET-1 mRNA. Thus, increased ET-1 expression in diabetic retina could be due to increased expression of PDGF-BB, mediated via PDGF-beta receptors in part by PKC activation. The novel demonstration of elevated expression of PDGF-B and its induction by PKC activation identifies a potential new molecular step in the pathogenesis of diabetic retinopathy.

Serum ceruloplasmin was reported to be an independent risk factor for cardiovascular disease. We investigated whether serum ceruloplasmin level is elevated in subjects with metabolic syndrome (MS, insulin resistance syndrome) in a community-based population. A total 883 subjects over 40 years of age were studied among a population of the Chongup district, a rural area of South Korea. Serum ceruloplasmin levels were measured, and oral glucose tolerance tests were performed. Known cardiovascular risk factors, such as serum lipids, fasting insulin level, and urinary albumin excretion rate (UAER), were also measured. Serum ceruloplasmin levels in the subjects with MS (n = 167, 325 +/- 141 mg/L) were significantly higher than in those without MS (278 +/- 93 mg/L, P <.001). The mean ceruloplasmin level also increased as the glucose tolerance worsened (278 +/- 95 mg/L in normal glucose tolerance [NGT], 303 +/- 108 mg/L in impaired glucose regulation, and 328 +/- 148 mg/L in diabetes; P <.001). Serum ceruloplasmin level was positively correlated with age, fasting glucose, postload 2-hour glucose, total cholesterol, triglyceride, systolic blood pressure, diastolic blood pressure, and UAER and negatively with high-density lipoprotein (HDL)-cholesterol. In multiple regression analysis, serum ceruloplasmin level was independently associated with age, fasting glucose, triglyceride, HDL-cholesterol, and UAER. In conclusion, serum ceruloplasmin level is elevated in the subjects with MS, as well as in subjects with impaired glucose regulation or diabetes mellitus. In addition, serum ceruloplasmin level is associated with various cardiovascular risk factors. These results suggest that elevated serum ceruloplasmin level can be a marker for metabolic stresses associated with MS., (Copyright 2002, Elsevier Science (USA). All rights reserved.)

Excessive proliferation of vascular smooth muscle cells (VSMCs) and neointimal formation are critical steps in the pathogenesis of atherosclerosis and restenosis after percutaneous transluminal angioplasty. In this study, we investigated the hypothesis that the activator protein-1 (AP-1) plays an important role in neointimal formation after vascular injury. A circular dumbbell AP-1 decoy oligodeoxynucleotide (CDODN) was developed as a novel therapeutic strategy for restenosis after angioplasty. This CDODN was more stable than the conventional phosphorothioate linear decoy ODN (PSODN) and maintained structural integrity on exposure to exonuclease III or serum. Transfection with AP-1 decoy ODNs strongly inhibited VSMC proliferation and migration, as well as glucose- and serum-induced expression of PCNA and cyclin A genes. Administration of AP-1 decoy ODNs in vivo using the hemagglutinating virus of Japan (HVJ)-liposome method virtually abolished neointimal formation after balloon injury to the rat carotid artery. Compared with PSODN, CDODN was more effective in inhibiting the proliferation of VSMCs in vitro and neointimal formation in vivo. Our results collectively indicate that AP-1 activation is crucial for the mediation of VSMC proliferation in response to vascular injury. Moreover, the use of stable CDODN specific for AP-1 activity in combination with the highly effective HVJ-liposome method provides a novel potential therapeutic strategy for the prevention of restenosis after angioplasty in humans.