Visfatin Promotes Monocyte Adhesion by Upregulating ICAM-1 and VCAM-1 Expression in Endothelial Cells via Activation of p38-PI3K-Akt Signaling and Subsequent ROS Production and IKK/NF-κB Activation.

BACKGROUND/AIMS: Visfatin is known to act as a mediator in several metabolic disorders, such as obesity, diabetes, and cardiovascular diseases. This study aimed to investigate the effect of visfatin on the adhesion of THP-1 monocytes to human vascular endothelial cells and the underlying mechanism. METHODS: Monocytes adhesion to endothelial cells was determined by using fluorescence-labeled monocytes. ICAM-1 and VCAM-1 expression in endothelial cells were measured by western blotting. Production of reactive oxygen species (ROS) was measured by using a fluorescent dye. The amounts of nuclear factor-kappa B (NF-κB) and phosphorylation of inhibitory factor of NF-κB (IκB) were determined by using western blot analysis. The translocation of NF-κB from the cytoplasm to the nucleus was determined by using immunofluorescence. RESULTS: Here we showed that visfatin significantly caused the upregulation of intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in endothelial cells, as well as enhanced monocyte adhesion to endothelial cells. Moreover, we found that inhibition of PI3K, Akt, and p38 MAPK activation significantly prevented visfatin-enhanced expression of ICAM-1 and VCAM-1 and monocyte adhesion to endothelial cells. Visfatin enhanced ROS production and IKK/NF-кB activation and then led to upregulation of ICAM-1 and VCAM-1 and enhanced monocyte adhesion to endothelial cells. These effects were also p38/PI3K/Akt-dependent. CONCLUSION: These results demonstrated that visfatin promoted monocyte-endothelial cell adhesion by increasing ICAM-1 and VCAM-1 expression via the activation of p38/PI3K/Akt signaling and downstream ROS production and IKK/NF-кB activation.

Using proteomics to discover novel biomarkers for fatty liver development and response to CB1R antagonist treatment in an obese mouse model.

Over activity of cannabinoid receptor type 1 (CB1R) plays a key role in increasing the incidence of obesity-induced non-alcoholic fatty liver disease. Tissue proteome analysis has been applied to investigate the bioinformatics regarding the mode of action and therapeutic mechanism. The aim of this study was to explore the potential pathways altered with CB1R in obesity-induced fatty liver. Male C57BL/6 mice were fed either a standard chow diet (STD) or a high-fat diet (HFD) with or without 1-week treatment of CB1R inverse agonist AM251 at 5 mg/kg. Then, liver tissues were harvested for 2DE analysis and protein profiles were identified by using MALDI-MS. Results showed that eight of significantly altered protein spots at the level of changes > twofold were overlapped among the three groups, naming major urinary protein 1, ATP synthase subunit ß, glucosamine-fructose-6-phosphate aminotransferase 1, zine finger protein 2, s-adenosylmethionine synthase isoform type-1, isocitrate dehydrogenase subunit α, epoxide hydrolase 2 and 60S acidic ribosomal protein P0. These identified proteins were involved in glucose/lipid metabolic process, xenobiotic metabolic system, and ATP synthesized process in mitochondria. Based on the findings, we speculated that CB1R blockade might exert its anti-metabolic disorder effect via improvement of mitochondrial function in hepatic steatosis in HFD condition.

Trans-ethnic fine-mapping of lipid loci identifies population-specific signals and allelic heterogeneity that increases the trait variance explained.

Genome-wide association studies (GWAS) have identified ~100 loci associated with blood lipid levels, but much of the trait heritability remains unexplained, and at most loci the identities of the trait-influencing variants remain unknown. We conducted a trans-ethnic fine-mapping study at 18, 22, and 18 GWAS loci on the Metabochip for their association with triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), respectively, in individuals of African American (n = 6,832), East Asian (n = 9,449), and European (n = 10,829) ancestry. We aimed to identify the variants with strongest association at each locus, identify additional and population-specific signals, refine association signals, and assess the relative significance of previously described functional variants. Among the 58 loci, 33 exhibited evidence of association at P<1 × 10(-4) in at least one ancestry group. Sequential conditional analyses revealed that ten, nine, and four loci in African Americans, Europeans, and East Asians, respectively, exhibited two or more signals. At these loci, accounting for all signals led to a 1.3- to 1.8-fold increase in the explained phenotypic variance compared to the strongest signals. Distinct signals across ancestry groups were identified at PCSK9 and APOA5. Trans-ethnic analyses narrowed the signals to smaller sets of variants at GCKR, PPP1R3B, ABO, LCAT, and ABCA1. Of 27 variants reported previously to have functional effects, 74% exhibited the strongest association at the respective signal. In conclusion, trans-ethnic high-density genotyping and analysis confirm the presence of allelic heterogeneity, allow the identification of population-specific variants, and limit the number of candidate SNPs for functional studies.

Major urinary protein 1 interacts with cannabinoid receptor type 1 in fatty acid-induced hepatic insulin resistance in a mouse hepatocyte model.

Hepatic insulin resistance (HIR) is a metabolic abnormality characterized by increased gluconeogenesis which usually contributes from an elevation of free fatty acids. Cannabinoid receptor type 1 (CB1R) and major urinary protein 1 (MUP1) are thought to play pivotal roles in mitochondrial dysfunction, liver steatosis and insulin resistance. The aim of this study was to explore the role of MUP1 in CB1R-mediated HIR through the dysregulation of mitochondrial function in AML12 mouse hepatocytes challenged with high concentration of free fatty acids (HFFA). Firstly we observed that treatment of AM251, a selective CB1R antagonist, obviously reversed the HFFA-induced reduction of MUP1 protein expression both in vivo and in vitro. Additionally, our results revealed that AM251 also reverted HFFA-mediated decrease of the mRNA level of mitochondrial biogenesis-related factors, mtDNA amount, ATP production, mitochondrial respiratory complexes-I and -III, and mitochondrial membrane potential, thus consequently might correlate with a parallel reduction of ROS production. Meanwhile, AM251 attenuated HFFA-induced impairment of insulin signaling phosphorylation and elevation of phosphoenolpyrvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase), two key enzymes of gluconeogenesis. Silence of MUP1 gene abolished the inhibitory effect of AM251 on HFFA-mediated elevation of PEPCK and G6Pase expression, whereas the suppression of insulin signaling and mRNA level of mitochondrial biogenesis-related factors were only partially recovered. Altogether, these findings suggest that the anti-HIR effect of AM251 via improvement of mitochondrial functions might occur in a MUP1-dependent manner.

Endothelin-1 exacerbates development of hypertension and atherosclerosis in modest insulin resistant syndrome.

Endothelin-1 (ET-1) is known as potent vasoconstrictor, by virtue of its mitogenic effects, and may deteriorate the process of hypertension and atherosclerosis by aggravating hyperplasia and migration in VSMCs. Our previous study demonstrated that insulin infusion caused sequential induction of hyperinsulinemia, hyperendothelinemia, insulin resistance, and then hypertension in rats. However, the underlying mechanism of ET-1 interfere insulin signaling in VSMCs remains unclear. To characterize insulin signaling during modest insulin resistant syndrome, we established and monitored rats by feeding high fructose-diet (HFD) until high blood pressure and modest insulin resistance occurred. To explore the role of ET-1/ETAR during insulin resistance, ETAR expression, ET-1 binding, and insulin signaling were investigated in the HFD-fed rats and cultured A-10 VSMCs. Results showed that high blood pressure, tunica medial wall thickening, plasma ET-1 and insulin, and accompanied with modest insulin resistance without overweight and hyperglycemia occurred in early-stage HFD-fed rats. In the endothelium-denuded aorta from HFD-fed rats, ETAR expression, but not ETBR, and ET-1 binding in aorta were increased. Moreover, decreasing of insulin-induced Akt phosphorylation and increasing of insulin-induced ERK phosphorylation were observed in aorta during modest insulin resistance. Interestingly, in ET-1 pretreated VSMCs, the increment of insulin-induced Akt phosphorylation was decreased whereas the increment of insulin-induced ERK phosphorylation was increased. In addition, insulin potentiated ET-1-induced VSMCs migration and proliferation due to increasing ET-1 binding. ETAR antagonist reversed effects of ET-1 on insulin-induced signaling and VSMCs migration and proliferation. In summary, modest insulin resistance syndrome accompanied with hyperinsulinemia leading to the potentiation on ET-1-induced actions in aortic VSMCs. ET-1 via ETAR pathway suppressed insulin-induced AKT activation, whereas remained insulin-induced ERK activation. ET-1 and insulin synergistically potentiated migration and proliferation mainly through ETAR/ERK dependent pathway, which is dominant in VSMCs during modest insulin resistance syndrome. Therefore, ET-1 and ETAR are potential targets responsible for the observed synergism effect in the hypertensive atherosclerotic process through enhancement of ET-1 binding, ET-1 binding, ETAR expression, and ET-1-induced mitogenic actions in aortic VSMCs.

Angiotensin II enhances endothelin-1-induced vasoconstriction through upregulating endothelin type A receptor.

Endothelin-1 (ET-1) is the most potent vasoconstrictor by binding to endothelin receptors (ETAR) in vascular smooth muscle cells (VSMCs). The complex of angiotensin II (Ang II) and Ang II type one receptor (AT1R) acts as a transient constrictor of VSMCs. The synergistic effect of ET-1 and Ang II on blood pressure has been observed in rats; however, the underlying mechanism remains unclear. We hypothesize that Ang II leads to enhancing ET-1-mediated vasoconstriction through the activation of endothelin receptor in VSMCs. The ET-1-induced vasoconstriction, ET-1 binding, and endothelin receptor expression were explored in the isolated endothelium-denuded aortae and A-10 VSMCs. Ang II pretreatment enhanced ET-1-induced vasoconstriction and ET-1 binding to the aorta. Ang II enhanced ETAR expression, but not ETBR, in aorta and increased ET-1 binding, mainly to ETAR in A-10 VSMCs. Moreover, Ang II-enhanced ETAR expression was blunted and ET-1 binding was reduced by AT1R antagonism or by inhibitors of PKC or ERK individually. In conclusion, Ang II enhances ET-1-induced vasoconstriction by upregulating ETAR expression and ET-1/ETAR binding, which may be because of the AngII/Ang II receptor pathways and the activation of PKC or ERK. These findings suggest the synergistic effect of Ang II and ET-1 on the pathogenic development of hypertension.

The forkhead transcription factor FOXO1 stimulates the expression of the adipocyte resistin gene.

Resistin is known as an adipocyte-specific hormone that can cause insulin resistance and decrease adipocyte differentiation. It can be regulated by transcriptional factors, but the possible role of forkhead transcription factor FOXO1 in regulating resistin gene expression is still unknown. Using 3T3 fibroblast and C3H10T1/2 and 3T3-L1 adipocytes, we found that transient overexpression of a non-phosphorylatable, constitutively active FOXO1, but not the wild type of FOXO1 or a DNA binding-deficient FOXO1, activated resistin promoter-directed luciferase expression. However, transient overexpression of a dominant-negative FOXO1 inactivated resistin promoter activity and reduced resistin mRNA expression. These observations indicate that the action of FOXO1 on resistin gene expression requires the activation of FOXO1 and that the effect of FOXO1 depends on the phosphorylation and dephosphorylation of FOXO1. The FOXO1 protein target sites on the resistin promoter were localized to the proximal -3545 to -787bp of 5'-flanking region of the resistin promoter. A chromatin immunoprecipitation assay also showed that FOXO1 bound the resistin promoter at nucleotide regions of -1539 to -1366bp and -1016 to -835bp, but not at the regions of -795 to -632bp. Results of this study suggest that FOXO1 transcription factor likely activates the expression of adipocyte resistin gene via direct association with the upstream resistin promoter.

Effect of growth hormone on dawn phenomenon in patients with type 2 diabetes.

We aimed to investigate the involvement of growth hormone in dawn phenomenon and insulin sensitivity in patients with type 2 diabetes mellitus (T2DM). On six occasions separated by intervals of at least 3 days, subjects received early evening (16:00 hours) or late night (23:00 hours) pretreatment with subcutaneous injection of normal saline, human growth hormone, or octreotide. Modified euglycemic insulin clamp test was done 16 hours later and variable glucose infusion (M values) was determined. Plasma glucose, serum insulin, insulin-like growth factor-1, non-esterified fatty acids, and metabolic clearance rate of insulin (MCRI) were measured. Early evening application of growth hormone decreased MCRI 16 hours later, suggesting reduction in insulin sensitivity. Exogenous growth hormone injection reduced insulin sensitivity in T2DM patients. Results provide direct evidence for the role of growth hormone in regulating the insulin sensitivity in insulin-resistant patients.

Aquaglyceroporin-7 overexpression in women with the polycystic ovary syndrome.

BACKGROUND: Aquaglyceroporin-7 (AQP7) is an adipose glycerol channel protein that has been suggested to be involved in whole-body glucose homeostasis and insulin sensitivity. The aim of this study was to investigate the expression of AQP7 in visceral adipose tissues from women with the polycystic ovary syndrome (PCOS). METHODS: AQP7 mRNA and protein levels were measured in omental adipose tissue from 5 women with the PCOS and 4 healthy controls matched for body mass index and age; this was done by the real-time polymerase chain reaction (PCR) and Western blotting. - RESULTS: The women with the PCOS had significantly higher homeostasis model insulin resistance indices (HOMA) and their quantitative insulin sensitivity check indices were significantly lower compared to the controls (p < 0.05). No significant difference was noted between the two groups for the plasma glycerol concentration. AQP7 mRNA expression and protein levels in omental adipose tissue from women with the PCOS were significantly higher than those of the controls (p = 0.007). AQP7 expression showed a positive correlation with fasting insulin levels, insulin levels at 2 h after glucose loading and HOMA in women with the PCOS. CONCLUSION: AQP7 overexpression may be related to insulin sensitivity and glucose homeostasis in women with the PCOS.

Potential effect of resistin on the ET-1-increased reactions of blood pressure in rats and Ca2+ signaling in vascular smooth muscle cells.

Resistin and endothelin-1 (ET-1) are upregulated in people with type II diabetes mellitus, central obesity, and hypertension. ET-1 signaling is involved in Ca(2+)-contraction coupling and related to blood pressure regulation. The aim of this study is to investigate the role of resistin on ET-1-increased blood pressure and Ca(2+) signaling. The blood pressure and cytosolic Ca(2+) of vascular smooth muscle cells (VSMCs) of Sprague-Dawley rats were detected. The data demonstrated that resistin accelerated and prolonged ET-1-induced increases in blood pressure and had significant effects on ET-1-increased Ca(2+) reactions. Resistin-enhanced ET-1-increased Ca(2+) reactions were reversed by blockers of store-operated Ca(2+) entry (SOCE) and extracellular-signal-regulated kinase (ERK). The endogenous expression of Orai and stromal interaction molecular (STIM) were characterized in the VSMCs. Furthermore, resistin-enhanced ET-1 Ca(2+) reactions and the resistin-dependent activation of SOCE were abolished under STIM1-siRNA treatment, indicating that STIM1 plays an important role in resistin-enhanced ET-1 Ca(2+) reactions in VSMCs. Resistin appears to exert effects on ET-1-induced Ca(2+) increases by enhancing the activity of ERK-dependent SOCE (STIM1-partcipated), and may accelerate and prolong ET-1-increased blood pressure via the same pathway.

Common ALDH2 genetic variants predict development of hypertension in the SAPPHIRe prospective cohort: gene-environmental interaction with alcohol consumption.

BACKGROUND: Genetic variants near/within the ALDH2 gene encoding the mitochondrial aldehyde dehydrogenase 2 have been associated with blood pressure and hypertension in several case-control association studies in East Asian populations. METHODS: Three common tag single nucleotide polymorphisms (tagSNP) in the ALDH2 gene were genotyped in 1,134 subjects of Chinese origin from the Stanford Asia-Pacific Program for Hypertension and Insulin Resistance (SAPPHIRe) family cohort. We examined whether the ALDH2 SNP genotypes predicted the development of hypertension in the prospective SAPPHIRe cohort. RESULTS: Over an average follow-up period of 5.7 years, carriers homozygous for the rs2238152 T allele in the ALDH2 gene were more likely to progress to hypertension than were non-carriers (hazard ratio [HR], 2.88, 95% confidence interval [CI], 1.06-7.84, P = 0.03), corresponding to a population attributable risk of ~7.1%. The risk associated with the rs2238152 T allele were strongest in heavy/moderate alcohol drinkers and was reduced in non-drinkers, indicating an interaction between ALDH2 genetic variants and alcohol intake on the risk of hypertension (P for interaction = 0.04). The risk allele was associated with significantly lower ALDH2 gene expression levels in human adipose tissue. CONCLUSION: ALDH2 genetic variants were associated with progression to hypertension in a prospective Chinese cohort. The association was modified by alcohol consumption.

Endothelin-1 stimulates suppressor of cytokine signaling-3 gene expression in adipocytes.

Endothelin (ET)-1 and suppressor of cytokine signaling (SOCS)-3 were respectively found to regulate energy metabolism and hormone signaling in fat cells. Although ET-1 can also regulate the expression of SOCS-3-stimulating hormones, it is still unknown whether ET-1 regulates SOCS-3 gene expression. This study investigated the pathways involved in ET-1's modulation of SOCS-3 gene expression in 3T3-L1 adipocytes. ET-1 upregulated SOCS-3 mRNA and protein expression in dose- and time-dependent manners. The concentration of ET-1 that increased SOCS-3 mRNA levels by 250-400% was ∼100nM with 2-4h of treatment. Treatment with actinomycin D prevented ET-1-stimulated SOCS-3 mRNA expression, suggesting that the effect of ET-1 requires new mRNA synthesis. Pretreatment with the ET type A receptor (ET(A)R) antagonist, BQ-610, but not the ET type B receptor (ET(B)R) antagonist, BQ-788, prevented the stimulatory effect of ET-1 on SOCS-3 gene expression. The specific inhibitors of either MEK1 (U-0126 and PD-98059), JAK (AG-490), JNK (SP-600125), or PI3K (LY-294002 and wortmannin) reduced ET-1-increased levels of SOCS-3 mRNA and respectively inhibited ET-1-stimulated activities of MEK1, JAK, JNK, and PI3K. These results imply that the ET(A)R, ERK, JAK, JNK, and PI3K are functionally necessary for ET-1's stimulation of SOCS-3 gene expression. Moreover, ET-1 was observed to upregulate expressions of SOCS-1, -2, -3, -4, -5, and -6 mRNAs, but not SOCS-7 or cytokine-inducible SH2-containing protein-1 mRNAs. This suggests that ET-1 selectively affects particular types of SOCS family members. Changes in SOCS gene expressions induced by ET-1 may help explain the mechanism by which ET-1 modulates hormone signaling of adipocytes.

Expression levels of vascular cell adhesion molecule-1 in young and nonobese women with polycystic ovary syndrome.

BACKGROUND/AIMS: The objective of this study was to measure levels of mRNAs for inflammatory markers and resistin in human peripheral blood mononuclear cells (PBMCs) in young and nonobese women with polycystic ovary syndrome (PCOS). METHODS: Fifteen young, nonobese women with PCOS and 10 age-matched controls were enrolled in this study. Levels of mRNAs for resistin and the inflammatory markers interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in human PBMCs were measured using real-time PCR. RESULTS: The mean age and BMI of the women with PCOS were 27.54 ± 6.3 years and 27.4 ± 5.7, respectively. The women with PCOS had significantly higher fasting and 2-hour insulin levels, homeostasis model assessment of insulin resistance index (HOMA(IR)) and total cholesterol levels than the controls. VCAM-1 and ICAM-1 mRNA levels were significantly higher in women with PCOS than in controls, whereas no differences in resistin, IL-6, TNF-α and MCP-1 mRNA levels were observed between the groups. After adjusting for the BMI, only VCAM-1 mRNA levels were significantly higher in women with PCOS than in controls and correlated with the HOMA(IR) and total cholesterol. CONCLUSION: Elevated VCAM-1 in human PBMCs in young, nonobese women with PCOS is associated with insulin resistance, independent of the BMI.

National trends in anti-diabetic treatment in Taiwan, 2000-2009.

BACKGROUND/PURPOSE: The impact of the introduction of newer anti-diabetic agents on the treatment pattern in the booming diabetic population remains unclear. We examined the patterns and temporal trends of anti-diabetic drug use in Taiwan, with particular emphasis on combination therapy. METHODS: We searched the Taiwan National Health Insurance Database during 2000-2009 to identify outpatient prescriptions of anti-diabetic drugs, including human insulins and insulin analogues, sulfonylureas, glinides, metformin, thiazolidinediones, alpha-glucosidase inhibitors, and dipeptidyl peptidase-4 inhibitors. Glucose-lowering treatments were classified according to pattern (oral agents only, insulins only, and oral agents and insulins combined) and a number of different classes of anti-diabetic drugs. Insulin therapy and combination therapy with two oral anti-diabetic drugs (OAD) were further classified according to individual drug combination patterns. RESULTS: Although metformin remained the mainstay of anti-diabetic treatment, patients receiving combination therapy of oral glucose-lowering agents, either with or without insulin, significantly increased, from approximately 40% in 2000 to 60% in 2009, particularly in relation to the newer agents, including glinides, alpha-glucosidase inhibitors, and long-acting insulin analogues. Use of sulfonylureas and thiazolidinediones decreased substantially. For insulin therapy, the most commonly prescribed drugs were premix insulin analogues and basal insulin analogues, accounting for one-third of total insulin prescriptions in 2009. CONCLUSION: We found an increasing complexity of anti-diabetic therapy during the past decade in Taiwan. Further studies are needed to evaluate whether this treatment pattern will lead to improved clinical outcomes in terms of cost-effectiveness.

Lower intake of magnesium and dietary fiber increases the incidence of type 2 diabetes in Taiwanese.

BACKGROUND/PURPOSE: Several studies have indicated an inverse association between the incidence of diabetes mellitus and magnesium and dietary fiber intake. Few studies have examined both of these associations together, not to mention in Asian populations with prospective study design. We therefore aimed to study how dietary magnesium and fiber intake levels affect diabetes incidence separately or in combination, in a prospective study in Taiwan. METHODS: The study subjects were recruited for a longitudinal study, CardioVascular Disease risk FACtor Two-township Study cycle 2 from November 1990. Data from complete baseline information on dietary and biochemical profile and at least one additional follow-up visit were gathered on a total of 1604 healthy subjects aged 30 years and over. Cox proportional hazard model was used to study the association between diabetes incidence and dietary magnesium and fiber intake level estimated from a food frequency questionnaire. RESULTS: A total of 141 diabetes mellitus events were identified and confirmed during the 4.6 years of follow-up (7365.1 person-years). A significantly higher diabetes risk was observed for people in the lowest quintile of total dietary fiber intake (hazard ratio = 2.04; 95% CI = 1.17-3.53) and magnesium intake (hazard ratio = 2.61; 95% CI = 1.42-4.79) compared with the highest quintile after adjusting for traditional cardiovascular disease risk factors. Similar inverse associations for total dietary fiber were also shown for vegetable fiber and fruit fiber. CONCLUSION: Lower magnesium, lower total dietary fiber intake, or lower intake of both was associated with higher risk of diabetes in the Taiwanese population. Clinical trials are required to confirm the protective effects of the adequate intake of fiber, magnesium, and/or their combination.

Diabetes-related kidney, eye, and foot disease in Taiwan: an analysis of the nationwide data for 2000-2009.

BACKGROUND/PURPOSE: Diabetes is one of the leading causes of dialysis, blindness, and amputation worldwide. However, the prevalence of diabetes-related kidney, eye, and foot diseases has not been investigated in national surveys. METHODS: In this study, we reviewed data sets of the National Health Insurance claims for the years 2000-2009. In 2009, the total population of Taiwan was 23 million. We de-identified the data and then analyzed them on inpatients and outpatients with diabetes mellitus, kidney diseases, eye diseases, peripheral vascular diseases (PVDs), and diabetic foot according to the International Classification of Diseases, 9(th) Revision with Clinical Modification diagnosis codes. RESULTS: The prevalence of diabetic nephropathy increased from 13.32% in 2000 to 15.42% in 2009. The corresponding diabetes dialysis rate increased from 1.5% to 2.46% during the same period (p < 0.001). The prevalence rates of retinopathy and PVD also increased (from 6.17% to 8.91%; p = 0.002 and from 1.87 to 2.47; p < 0.001, respectively). More than 94% of the patients treated for diabetic foot in the hospital had an associated foot infection. The prevalence of in-hospital diabetic foot decreased from 1.68% to 1.02% during the years 2000-2009 (p < 0.001), while the rates of lower extremity amputation as the treatment outcome did not show improvement (mean amputation rate: 28.35%). CONCLUSION: During the years 2000-2009, patients with diabetes in Taiwan had an increased risk for kidney, eye, and PVDs. Multidisciplinary teams need to be set up for the treatment of complications related to diabetic foot, and preventions programs that are specifically designed to target these complications should now be made mandatory.

Combined lipid goal attainment in patients with type 2 diabetes and dyslipidemia: A head-to-head comparative trial of statins.

BACKGROUND: This study compared the efficacy of two statin treatments (simvastatin vs rosuvastatin) in achieving the combined goal of low-density lipoprotein cholesterol (LDL-C) <2.6 mmol/L and non-high-density lipoprotein cholesterol (non-HDL-C) <3.4 mmol/L in patients with type 2 diabetes and dyslipidemia. METHODS: After a 5-week run-in, 89 patients with type 2 diabetes having fasting triglyceride (TG) levels of 1.7 to 5.7 mmol/L or non-HDL-C levels of 3.4 to 5.2 mmol/L were randomized to receive simvastatin 20 mg daily for 4 weeks followed by 40 mg for 8 weeks or rosuvastatin 10 mg for 4 weeks followed by 20 mg for 8 weeks. The primary end-point was the percentage of patients achieving the combined goal at week 12. RESULTS: Although significant between-group differences were observed in changes in LDL-C and non-HDL-C levels, both study treatments were sufficiently intensive for a 40% to 55% LDL-C reduction. At the end of the study, the two groups had similar percentages of patients who achieved the combined lipid goal (84% vs 89%, p = 0.66). All patients who attained the combined lipid goal also met the apolipoprotein B (Apo-B) target of <0.9 g/L. No between-group differences were noted in changes in HDL-C and TG levels at week 12. The patients tolerated both treatments well. CONCLUSION: In our study, ≈85% of patients with type 2 diabetes and dyslipidemia could achieve the combined lipid goal with statin monotherapy. The two statin treatments could sufficiently control diabetic dyslipidemia (NCT00506961).

Endothelin-1 induces lipolysis through activation of the GC/cGMP/Ca2+/ERK/CaMKIII pathway in 3T3-L1 adipocytes.

Endothelin-1 (ET-1) is a potent vasoconstrictive peptide produced and secreted mainly by endothelial cells. Recent studies indicate that ET-1 can regulate lipid metabolism, which may increase the risk of insulin resistance. Our previous studies revealed that ET-1 induced lipolysis in adipocytes, but the underlying mechanisms were unclear. 3T3-L1 adipocytes were used to investigate the effect of ET-1 on lipolysis and the underlying mechanisms. Glycerol levels in the incubation medium and hormone-sensitive lipase (HSL) phosphorylation were used as indices for lipolysis. ET-1 significantly increased HSL phosphorylation and lipolysis, which were completely inhibited by ERK inhibitor (PD98059) and guanylyl cyclase (GC) inhibitor (LY83583). LY83583 reduced ET-1-induced ERK phosphorylation. A Ca2+-free medium and PLC inhibitor caused significant decreases in ET-1-induced lipolysis as well as ERK and HSL phosphorylation, and IP3 receptor activator (D-IP3) increased lipolysis. ET-1 increased cGMP production, which was not affected by depletion of extracellular Ca2+. On the other hand, LY83583 diminished the ET-1-induced Ca2+ influx. Transient receptor potential vanilloid-1 (TRPV-1) antagonist and shRNA partially inhibited ET-1-induced lipolysis. ET-1-induced lipolysis was completely suppressed by CaMKIII inhibitor (NH-125). These results indicate that ET-1 stimulates extracellular Ca2+ entry and activates the intracellular PLC/IP3/Ca2+ pathway through a cGMP-dependent pathway. The increased cytosolic Ca2+ that results from ET-1 treatment stimulates ERK and HSL phosphorylation, which subsequently induces lipolysis. ET-1 induces HSL phosphorylation and lipolysis via the GC/cGMP/Ca2+/ERK/CaMKIII signaling pathway in 3T3-L1 adipocytes.

Endothelin-1 exacerbates lipid accumulation by increasing the protein degradation of the ATP-binding cassette transporter G1 in macrophages.

Endothelin-1 (ET-1), a potent proatherogenic vasoconstrictive peptide, is known to promote macrophage foam cell formation via mechanisms that are not fully understood. Excessive lipid accumulation in macrophages is a major hallmark during the early stages of atherosclerotic lesions. Cholesterol homeostasis is tightly regulated by scavenger receptors (SRs) and ATP-binding cassette (ABC) transporters during the transformation of macrophage foam cells. The aim of this study was to investigate the possible mechanisms by which ET-1 affects lipid accumulation in macrophages. Our results demonstrate that oxidized low-density lipoprotein (oxLDL) treatment increases lipid accumulation in rat bone marrow-derived macrophages. Combined treatment with ET-1 and oxLDL significantly exacerbated lipid accumulation in macrophages as compared to treatment with oxLDL alone. The results of Western blotting show that ET-1 markedly decreased the ABCG1 levels via ET type A and B receptors and activation of the phosphatidylinositol 3-kinase pathway; however, ET-1 had no effect on the protein expression of CD36, SR-BI, SR-A, or ABCA1. In addition, real-time PCR analysis showed that ET-1 treatment did not affect ABCG1 mRNA expression. We also found that ET-1 decreases ABCG1 possibly due to the enhancement of the proteosome/calpain pathway-dependent degradation of ABCG1. Moreover, ET-1 significantly reduced the efficiency of the cholesterol efflux in macrophages. Taken together, these findings suggest that ET-1 may impair cholesterol efflux and further exacerbate lipid accumulation during the transformation of macrophage foam cells.

Resistin induces monocyte-endothelial cell adhesion by increasing ICAM-1 and VCAM-1 expression in endothelial cells via p38MAPK-dependent pathway.

Resistin, firstly reported as an adipocyte-specific hormone, is suggested to be an important link between obesity and diabetes. Recent studies have suggested an association between resistin and atherogenic processes. The adhesion of circulating monocytes to endothelial cells is a critical step in the early stages of atherosclerosis. The purpose of the present study was to investigate the effect of resistin on the adhesion of THP-1 monocytes to human umbilical vein endothelial cells (HUVECs) and the underlying mechanism. Our results showed that resistin caused a significant increase in monocyte adhesion. In exploring the underlying mechanisms of resistin action, we found that resistin-induced monocyte adhesion was blocked by inhibition of p38MAPK activation using SB203580 and SB202190. Furthermore, resistin increased the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) by HUVECs and these effects were also p38MAPK-dependent. Resistin-induced monocyte adhesion was also blocked by monoclonal antibodies against ICAM-1 and VCAM-1. Taken together, these results show that resistin increases both the expression of ICAM-1 and VCAM-1 by endothelial cells and monocyte adhesion to HUVECs via p38MAPK-dependent pathways.