Vaspin inhibits cytokine-induced nuclear factor-kappa B activation and adhesion molecule expression via AMP-activated protein kinase activation in vascular endothelial cells

Background

Vaspin is an adipocytokine that was recently identified in the visceral adipose tissue of diabetic rats and has anti-diabetic and anti-atherogenic effects. We hypothesized that vaspin prevents inflammatory cytokine-induced nuclear factor-kappa B (NF-κB) activation by activating AMP-activated protein kinase (AMPK) in vascular endothelial cells.

Methods

We examined the effects of vaspin on NF-κB activation and the expression of the NF-κB-mediated genes intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and monocyte chemoattractant protein-1 (MCP-1). Human aortic endothelial cells (HAECS) were used. Tumor necrosis factor alpha (TNFα) was used as a representative proinflammatory cytokine.

Results

Treatment with vaspin significantly increased the phosphorylation of AMPK and acetyl-CoA carboxylase, the down-stream target of AMPK. Furthermore, treatment with vaspin significantly decreased TNFα-induced activation of NF-κB, as well as the expression of the adhesion molecules ICAM-1, VCAM-1, E-selectin, and MCP-1. These effects were abolished following transfection of AMPKα1-specific small interfering RNA. In an adhesion assay using THP-1 cells, vaspin reduced TNFα-induced adhesion of monocytes to HAECS in an AMPK-dependent manner.

Conclusions

Vaspin might attenuate the cytokine-induced expression of adhesion molecule genes by inhibiting NF-κB following AMPK activation.

Risk of bladder cancer among patients with diabetes treated with a 15 mg pioglitazone dose in Korea: a multi-center retrospective cohort study

It has not yet been determined whether chronic exposure to relatively low doses of pioglitazone increases risk of bladder cancer. We aimed to assess the risk of bladder cancer associated with pioglitazone in Korean patients. This was a retrospective cohort study of diabetic patients who had ≥ 2 clinic visits between November 2005 and June 2011 at one of four tertiary referral hospitals in Korea. A prevalent case-control analysis nested within the cohort was conducted to further adjust confounders. A total of 101,953 control patients and 11,240 pioglitazone-treated patients were included, in which there were 237 and 30 cases of incidental bladder cancer (64.9 and 54.9 per 100,000 person-years; age, sex-adjusted HR 1.135, 95% confidence interval [CI] 0.769-1.677), respectively. In the prevalent case-control analysis nested within the cohort, use of pioglitazone for a duration of > 6 months, but not ever use of pioglitazone, was associated with an increased rate of bladder cancer as compared to never use of pioglitazone. In conclusion, we failed to exclude the possible association between use of pioglitazone for a duration of > 6 months and bladder cancer.

Higher serum bilirubin level as a protective factor for the development of diabetes in healthy Korean men: a 4 year retrospective longitudinal study

OBJECTIVE

Bilirubin, a natural product of heme catabolism by heme oxygenase, one of key antioxidant enzymes, has been recognized as a substance with potent antioxidant and cytoprotective properties. Several studies have shown a significant negative relationship between serum bilirubin levels and the risk of metabolic disorders, including type 2 diabetes. However, longitudinal studies investigating the association of elevated serum bilirubin levels and type 2 diabetes are lacking. In the present study, we aimed to investigate the longitudinal effects of baseline serum bilirubin concentrations on the development of type 2 diabetes in healthy Korean men.

MATERIALS AND METHODS

This 4 year retrospective longitudinal observational study was conducted at the Asan Medical Center, Seoul, Republic of Korea. The study population consisted of 5960 men without type 2 diabetes who underwent routine health examinations in 2007 (baseline) and 2011 (follow-up). Baseline serum bilirubin concentrations were determined by the vanadate oxidation method.

RESULTS

During a 4 year period, 409 incident cases of diabetes (6.9 %) were identified. Incident type 2 diabetes decreased across the baseline bilirubin quartile categories (P for trend <0.001). In multivariable-adjusted model, the relative risk (RR) for the development of type 2 diabetes was significantly lower in the highest (i.e., 1.30-2.00 mg/dl) than in the lowest bilirubin quartile category (i.e., ≤ 0.90 mg/dl), even after adjustment for confounding variables (RR=0.69, 95% confidence interval 0.48-0.99, P for trend = 0.041).

CONCLUSIONS

The results indicate that serum total bilirubin level may provide additional information for predicting future development of type 2 diabetes in healthy subjects.

The optimal morning:evening ratio in total dose of twice-daily biphasic insulin analogue in poorly controlled Type 2 diabetes: a 24-week multi-centre prospective, randomized controlled, open-labelled clinical study

AIMS

Biphasic insulin analogues are widely used in patients with Type 2 diabetes mellitus suboptimally controlled on oral anti-diabetic drugs. Several topics in this area remain controversial, including how to divide the daily dose of biphasic insulin analogue. We aimed to determine the optimal dosing ratio of twice-daily biphasic insulin analogue and to compare the glycaemic efficacy among groups of patients using different initial dosing ratios of biphasic insulin analogue.

METHODS

A total of 100 poorly controlled insulin-naive subjects with Type 2 diabetes [HbA1c ≥ 58 mmol/mol, (7.5%)] on oral anti-diabetic drugs were randomized into three groups according to initial morning:evening dosing ratio (group I, 50:50; group II, 55:45; group III, 60:40) of twice-daily biphasic insulin analogue (biphasic insulin aspart 70/30, biphasic insulin aspart 30). The primary outcome measure was the difference in pre-breakfast to pre-dinner dose ratio at the end of the study.

RESULTS

Twice-daily biphasic insulin analogue showed a significant improvement in glycaemic control [HbA1c from 70 mmol/mol (8.6%) to 60 mmol/mol (7.6%)] after 24 weeks regardless of the initial dose ratio given. Despite the similar efficacy and safety profiles among three groups, morning dose was significantly increased (from 50:50 to 55:45-60:40) in group I after 24 weeks. However, there was no significant change in splitting ratio in groups II and III (with higher morning dose) over the 24-week treatment period.

CONCLUSIONS

These results indicate that initiating twice-daily biphasic insulin analogue on regimens with a higher dose before breakfast than before dinner (i.e. ratio approximately 55:45 to 60:40) might be more appropriate in Korean subjects with Type 2 diabetes.

Elevated serum ferritin level is associated with the incident type 2 diabetes in healthy Korean men: a 4 year longitudinal study

Background

Elevated ferritin concentration has been implicated in the etiology of type 2 diabetes. Accumulating evidence, mostly from studies conducted on western populations, has demonstrated a strong association between the elevated ferritin concentrations and incident type 2 diabetes. In Asian populations, however, the longitudinal studies investigating the association of elevated serum ferritin levels and type 2 diabetes are lacking. In present study, we aimed to determine whether elevated serum ferritin levels are related to the incident type 2 diabetes in healthy Korean men.

Methodology/Principal Findings

This 4 year longitudinal observational study was conducted at the Asan Medical Center, Seoul, Republic of Korea. The study population consisted of 2,029 men without type 2 diabetes who underwent routine health examination in 2007 (baseline) and 2011 (follow-up). Baseline serum ferritin concentrations were measured by chemiluminescent two-site sandwich immunoassay. In multiple-adjusted model, the relative risk (RR) for incident type 2 diabetes was significantly higher in highest compared with the lowest ferritin quartile category, even after adjusting for confounding variables including homeostasis model assessment of insulin resistance (RR = 2.17, 95% confidence interval 1.27–3.72, P for trend = 0.013).

Conclusions/Significance

These results demonstrated that elevated level of serum ferritin at baseline was associated with incident type 2 diabetes in an Asian population.

Clinical characteristics and insulin independence of Koreans with new-onset type 2 diabetes presenting with diabetic ketoacidosis

BACKGROUND

We evaluated the incidence, characteristics and insulin independence of Koreans with new-onset type 2 diabetes (T2D) initially presenting with diabetic ketoacidosis (DKA).

METHODS

We analysed clinical and biochemical data from diabetic patients presenting with DKA. They were classified into ketosis-prone diabetes (KPD) type 1A (KPD-T1A) (A+β-), type 1B (KPD-T1B) (A-β-), type 2A (KPD-T2A) (A+β+) or type 2B (KPD-T2B) (A-β+) according to the presence or absence of an autoantibody and β-cell reserve. Changes in therapy after insulin discontinuation were evaluated for up to 4 years. We also compared clinical and biochemical characteristics between newly diagnosed T2D patients presenting with DKA and previously diagnosed T2D patients presenting with DKA.

RESULTS

Among 60 newly diagnosed KPD patients, 18, 21 and 21 patients were classified as KPD-T1A, KPD-T1B and KPD-T2B, respectively. In the KPD-T2B group, both fasting and stimulated C-peptide were recovered over 6 months. After 4 years of DKA development, 75% of KPD-T2B subjects no longer required insulin. Compared with previously diagnosed T2D patients presenting with DKA, newly diagnosed KPD-T2B patients tended to be younger, more obese and showed better insulin secretory function after recovery from DKA.

CONCLUSIONS

New-onset T2D patients presenting with DKA was not uncommon among the Korean population. In contrast to previously diagnosed T2D patients presenting with DKA, who showed a progressive decrease in insulin secretory function, new-onset KPD-T2B patients recovered insulin secretory function over time, and insulin independence could be expected.

The preventive effect of uncarboxylated osteocalcin against free fatty acid-induced endothelial apoptosis through the activation of phosphatidylinositol 3-kinase/Akt signaling pathway

OBJECTIVE

Increasing evidence suggests that osteocalcin (OC), one of the osteoblast-specific proteins, has been associated with atherosclerosis, but results are conflicting. The aim of this study was to elucidate the independent effect of uncarboxylated osteocalcin (ucOC), an active form of osteocalcin which has been suggested to have an insulin sensitizing effect, on vascular endothelial cells.

MATERIALS AND METHODS

We used human aortic endothelial cells and treated them with ucOC. Linoleic acid (LA) was used as a representative free fatty acid. Apoptosis was evaluated using various methods including a terminal deoxyribonucleotide transferase-mediated deoxyuridine triphosphate nick-end labeling analysis kit and Western blotting for cleaved caspase 3, cleaved poly (ADP-ribose) polymerase and Bcl-xL. The phosphorylations of Akt and endothelial nitric oxide synthase (eNOS) as well as the level of NO were measured to confirm the effect of ucOC on insulin signaling pathway.

RESULTS

Pretreatment of ucOC (30 ng/ml) prevented LA-induced apoptosis in insulin-stimulated endothelial cells; effects were abolished by pretreatment with the phosphatidylinositol 3-kinase (PI3-kinase) inhibitor, wortmannin. Treatment of ucOC (ranged from 0.3 to 30 ng/ml) significantly increased the phosphorylation of Akt and eNOS and nitric oxide secretion from endothelial cells in a PI3-kinase dependent manner.

CONCLUSIONS

Our study is the first to demonstrate the independent effect of ucOC on vascular endothelial cells. Our results further suggest that ucOC could have beneficial effects on atherosclerosis.

Pro-apoptotic and migration-suppressing potential of EGCG, and the involvement of AMPK in the p53-mediated modulation of VEGF and MMP-9 expression

The present study investigated the regulatory mechanisms by which epigallocatechin-3-gallate (EGCG) exerts vascular endothelial growth factor (VEGF)-, p53- and AMP-activated protein kinase (AMPK)-associated pro-apoptotic and migration-suppressing effects on colon cancer cells. EGCG decreased the expression levels of VEGF and matrix metalloproteinase (MMP)-9. EGCG treatment induced apoptosis in the presence of wild-type and mutant p53, indicating that a p53-independent pathway may contribute to EGCG-induced apoptosis in these cells. EGCG showed migration-suppressing effects, suggesting that this activity may also have p53-dependent and -independent components. The interaction between p53 and VEGF in the EGCG-treated cells was investigated using pifithrin-α. Notably, the suppression of p53 activity blocked the ability of EGCG to inhibit VEGF and MMP-9 in the cells expressing wild-type p53, but not mutant p53, indicating that the effects of EGCG on VEGF may be p53-dependent or -independent. Finally, although AMPK and VEGF did not appear to co-localize, the results indicated that AMPK controls VEGF in EGCG-treated cells regardless of the p53 status.

Association of apolipoprotein b/apolipoprotein A1 ratio and coronary artery stenosis and plaques detected by multi-detector computed tomography in healthy population

Despite the noninvasiveness and accuracy of multidetector computed tomography (MDCT), its use as a routine screening tool for occult coronary atherosclerosis is unclear. We investigated whether the ratio of apolipoprotein B (apoB) to apolipoprotein A1 (apoA1), an indicator of the balance between atherogenic and atheroprotective cholesterol transport could predict occult coronary atherosclerosis detected by MDCT. We collected the data of 1,401 subjects (877 men and 524 women) who participated in a routine health screening examination of Asan Medical Center. Significant coronary artery stenosis defined as > 50% stenosis was detected in 114 subjects (8.1%). An increase in apoB/A1 quartiles was associated with increased percentages of subjects with significant coronary stenosis and noncalcified plaques (NCAP). After adjustment for confounding variables, each 0.1 increase in serum apoB/A1 was significantly associated with increased odds ratios (ORs) for coronary stenosis and NCAP of 1.23 and 1.18, respectively. The optimal apoB/A1 ratio cut off value for MDCT detection of significant coronary stenosis was 0.58, which had a sensitivity of 70.2% and a specificity of 48.2% (area under the curve, 0.61; 95% CI, 0.58-0.63, P < 0.001). Our results indicate that apoB/A1 ratio is a good indicator of occult coronary atherosclerosis detected by coronary MDCT.

Assessment of the fatty liver index as an indicator of hepatic steatosis for predicting incident diabetes independently of insulin resistance in a Korean population

AIMS

Fatty liver disease, especially non-alcoholic fatty liver disease, is considered to be the hepatic manifestation of the metabolic syndrome, both closely associated with insulin resistance. Furthermore, fatty liver disease assessed by ultrasonography is known to be a predictor of the development of Type 2 diabetes mellitus. However, it remains unclear whether fatty liver disease plays a role in the pathogenesis of Type 2 diabetes independently of insulin resistance. In this study, we investigated whether fatty liver disease assessed by the fatty liver index can predict the development of Type 2 diabetes independently of systemic insulin resistance.

METHODS

We examined the clinical and laboratory data of 7860 subjects without diabetes who underwent general routine health evaluations at the Asan Medical Center in 2007 and had returned for follow-up examinations in 2011. Fatty liver index was calculated using an equation that considers serum triglyceride levels, γ-glutamyltransferase, waist circumference and BMI.

RESULTS

During a 4-year period, 457 incident diabetes cases (5.8%) were identified. The odds ratios for the development of Type 2 diabetes were significantly higher in the group with a fatty liver index ≥ 60 (fatty liver index-positive) than in the group with a fatty liver index < 20 (fatty liver index-negative) after adjusting for various confounding variables including homeostasis model assessment of insulin resistance. Odds ratios were significant regardless of the insulin resistance status at baseline.

CONCLUSIONS

Our results suggest that fatty liver index as a simple surrogate indicator of hepatic steatosis is valuable in identifying subjects at high risk for Type 2 diabetes. In addition, fatty liver disease itself contributes to the development of Type 2 diabetes independently of systemic insulin resistance.

Association between serum ceruloplasmin levels and arterial stiffness in Korean men with type 2 diabetes mellitus

BACKGROUND

Increased oxidative stress contributes to the development of arterial stiffness. Arterial stiffness, as measured by brachial-ankle pulse wave velocity (baPWV), has been known to be correlated with oxidative stress. Serum ceruloplasmin (CP), a copper-carrying protein, may indicate the overall level of oxidative stress in the body. The present study investigated whether serum CP levels are associated with baPWV in Korean men with type 2 diabetes mellitus (DM).

SUBJECTS AND METHODS

Serum CP levels and conventional risk factors were measured in 760 Korean men with type 2 DM. Arterial stiffness was assessed by baPWV obtained with an automatic device (model VP-1000; Colin, Komaki, Japan).

RESULTS

Correlation analysis indicated a significant positive association between serum CP and baPWV (r = 0.109, P = 0.003). Age-adjusted baPWV increased gradually according to serum CP quartiles (Q1, 1,500.3 ± 18.4 cm/s; Q2, 1,511.6 ± 17.8 cm/s; Q3, 1,551.8 ± 17.9 cm/s; Q4, 1,622.1 ± 17.8 cm/s; P for trend < 0.001). Multivariate linear regression analysis showed that serum CP was independently associated with baPWV in various models.

CONCLUSIONS

A positive relationship was identified between CP and baPWV in adult male subjects with type 2 DM, which was independent of conventional cardiovascular risk factors. Further studies are needed to confirm whether CP contributes to the pathogenesis of increased arterial stiffness in subjects with type 2 DM.

High prevalence of both anti-insulin and anti-insulin receptor antibodies in Korean patients with insulin autoimmune syndrome

We performed a retrospective pooled analysis of 28 patients who had been diagnosed with insulin autoimmune syndrome and evaluated the prevalence of anti-insulin receptor antibodies. Dual positivity for anti-insulin and anti-insulin receptor antibodies was common (53.8%). However, these patients had a similar phenotype compared with insulin receptor antibody-negative patients.

The value of apolipoprotein B/A1 ratio in the diagnosis of metabolic syndrome in a Korean population

OBJECTIVE

The ratio of apolipoprotein B (apoB) to apolipoprotein A1 (apoA1) has been reported to be associated with the metabolic syndrome (MetS). However, the optimal cut-off value of apoB/A1 ratio for detecting subjects with MetS has remained undetermined. In the present study, we aimed to investigate whether apoB/A1 ratio can be an indicator of MetS and to determine the optimal cut-off value of apoB/A1 ratio in detecting subjects with MetS in a Korean population.

DESIGN

This cross-sectional study was conducted at the Asan Medical Center, Seoul, Republic of Korea.

SUBJECTS AND MEASUREMENTS

We collected the data of 10,940 subjects who participated in a routine health screening examination regarding conventional risk factors and serum levels of apoB and apoA1.

RESULTS

The odds for MetS were significantly higher in the highest compared with the lowest apoB/A1 ratio quartiles, after adjustment for confounding variables, in both men [odds ratio (OR) = 4·07, 95% CI = 3·42-4·84] and women (OR = 8·41, 95% CI = 5·85-12·08). The optimal apoB/A1 ratio cut-off value for the detection of MetS was 0·65, which had a sensitivity of 63·5% and a specificity of 61·3% (area under the curve = 0·67, 95% CI = 0·66-0·68, P < 0·001) in men and 0·62, which had a sensitivity of 67·9% and a specificity of 61·9% (area under the curve = 0·70, 95% CI = 0·69-0·71, P < 0·001) in women.

CONCLUSIONS

These results suggest that apoB/A1 ratio is independently associated with MetS and that an apoB/A1 ratio >0·65 in men and 0·62 in women is a marker of MetS independent from conventional risk factors.

The duration of sulfonylurea treatment is associated with β-cell dysfunction in patients with type 2 diabetes mellitus

BACKGROUND

This study investigated the incidence of β-cell dysfunction and the clinical and biochemical factors affecting that in patients with type 2 diabetes having more than 3 years of follow-up.

SUBJECTS AND METHODS

β-Cell dysfunction was assessed by measuring changes in the fasting serum C-peptide concentrations. Patients were classified into two groups: cases showing a decreased (Group D) or an unchanged or increased (Group I) C-peptide concentration from the baseline.

RESULTS

Of the 504 patients included in this study, 259 (51%) showed decreased C-peptide concentrations, of whom 20% showed a decrease of ≥50%. Most patients, however, had a final C-peptide concentration of ≥1 ng/mL, with only 18 (4%) individuals having a level <0.6 ng/mL. Patients in Group D had a longer duration of diabetes, higher initial hemoglobin A1c concentration, and longer treatment durations with sulfonylurea and insulin compared with Group I. After adjusting for diabetes duration and C-peptide follow-up period, the duration of sulfonylurea treatment was found to be the only factor independently associated with decreases in the C-peptide concentration.

CONCLUSIONS

Although β-cell function deteriorates over time in patients with type 2 diabetes, these cases mainly have fasting serum C-peptide concentrations of ≥1 ng/mL. A longer treatment duration with sulfonylurea is associated with a more rapid decline in the C-peptide concentration.

The role of Rho/Rho-kinase pathway in the expression of ICAM-1 by linoleic acid in human aortic endothelial cells

Linoleic acid (LA), a dietary unsaturated fatty acid, has been known to increase the expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) through the activation of nuclear factor-kappa B. Rho/Rho-kinase (ROCK) pathway mediates various cellular functions related to cardiovascular disease and affects the expression of ICAM-1. However, the exact mechanism underlying this action has not been fully elucidated. In this study, we aimed to find out the role of Rho/ROCK pathway in LA-induced ICAM-1 expression in human aortic endothelial cells (HAECs). We found that LA increased ICAM-1 expression and phosphorylation of ROCK and MYPT-1, a distal signal of ROCK. Y-27632, a ROCK inhibitor, suppressed ICAM-1 expression and phosphorylation of MYPT-1 induced by LA. The effect of LA on the increased phosphorylation of MYPT1 and expression of ICAM-1 was abolished by knocking down RhoA and ROCK2 protein level expression using small interfering RNA. LA increased NF-κB DNA-binding activity, which was inhibited with pretreatment with Y-27632. This study suggests that Rho/ROCK pathway plays a role in LA-induced ICAM-1 expression, which is possibly mediated by NF-κB in HAECs.

Low Density Lipoprotein Cholesterol Target Goal Attainment Rate and Physician Perceptions about Target Goal Achievement in Korean Patients with Diabetes

BACKGROUND

This study aims to investigate the discrepancy between clinicians' perceptions and actual achievement rates of low density lipoprotein cholesterol (LDL-C) in Korean patients with diabetes according to updated American Diabetes Association (ADA)/American College of Cardiology Foundation (ACC) recommendations.

METHODS

This is a multi-center, retrospective, non-interventional, observational study. Diabetic patients aged 18 years or older were eligible if they had been diagnosed with hypercholesterolemia or were receiving a lipid-lowering therapy between May 2010 and August 2010. The information was obtained by reviewing medical records and using a self-completed questionnaire to examine physician perceptions.

RESULTS

A total of 2,591 subjects who satisfied the inclusion criteria were enrolled. Highest-risk and high-risk patients accounted for 61.9% and 38.1% of the patients, respectively. Although most (96.3%) underwent a statin monotherapy or a statin-based combination therapy, just 47.4% of patients attained the LDL-C target. However, the physicians' perceptions on target achievement rate (70.6%) were different from the actual results (47.4%). Many patients (65.3%) remained on the starting doses of statins, despite evidence of poor achievement of lipid goals.

CONCLUSION

Only less than half of patients with diabetes attained the LDL-C goal. The surveys showed that poor physician performance might be due to the lack of recognition on ADA/ACC consensus causing a low LDL-C target attainment rate. Therefore, changes in doctor perception are needed to attain target LDL-C level and reduce cardiovascular risk in Korean patients with diabetes.

The prevalence of peripheral arterial disease in korean patients with type 2 diabetes mellitus attending a university hospital

BACKGROUND

Peripheral arterial disease (PAD) is a common manifestation of systemic atherosclerosis and is associated with significant morbidity and mortality. Diabetes is known to increase the risk of PAD two- to four-fold. The prevalence of PAD in Korean diabetic patients has not been established. In this study, we investigated the prevalence of PAD in Korean patients with type 2 diabetes attending a large university hospital and analyzed the factors associated with PAD.

METHODS

A total of 2,002 patients with type 2 diabetes who underwent ankle-brachial index (ABI) measurement in an outpatient clinic were enrolled. PAD was defined as an ABI ≤0.9. Clinical characteristics of 64 patients with PAD were compared with those of 192 age- and sex-matched control patients without PAD.

RESULTS

Of the 2,002 type 2 diabetic patients, 64 (3.2%) were diagnosed as having PAD. PAD was associated with higher prevalences of retinopathy, nephropathy, neuropathy, cerebrovascular and coronary artery disease. Patients with PAD had higher systolic blood pressure and serum triglyceride level and reported higher pack-years of smoking. Multivariate analysis showed that the presence of micro- and macrovascular complications and high systolic blood pressure are factors independently associated with PAD.

CONCLUSION

The prevalence of PAD in diabetic patients was 3.2%, suggesting that the prevalence in Korean diabetic patients is lower than that of patients in Western countries.

Elevated serum ceruloplasmin levels are associated with albuminuria in Korean men with type 2 diabetes mellitus

The aim of this study was to examine the possible association between serum ceruloplasmin, a copper carrying protein, and albuminuria in 456 males with type 2 diabetes. Multivariate regression analysis demonstrated that elevated serum ceruloplasmin was a determinant of albuminuria independently of conventional risk factors.

Serum gamma-glutamyltransferase is associated with arterial stiffness in healthy individuals

OBJECTIVE

Gamma-glutamyltransferase (GGT) has been reported to be useful in predicting cardiovascular disease. Arterial stiffness measured by brachial-ankle pulse wave velocity (baPWV) is not only a marker of vascular damage but a significant predictor of cardiovascular events. Gender difference has been reported in the association between GGT and baPWV. We assessed, therefore, the association between GGT and baPWV in a large population and determined whether there was gender difference.

DESIGN

This cross-sectional study was conducted at the Asan Medical Centre, Seoul, Republic of Korea.

SUBJECTS AND MEASUREMENTS

Serum GGT, baPWV and conventional risk factors were measured in 10 988 apparently healthy subjects (7248 men, 3740 women) who participated in a routine health screening examination.

RESULTS

In both men and women, we observed positive linearity between GGT quartiles and body mass index, waist circumference, systolic blood pressure, diastolic blood pressure, fasting plasma glucose, total cholesterol, LDL cholesterol, triglycerides, uric acid, high-sensitive C-reactive protein (hsCRP) and homeostatic model assessment of insulin resistance (HOMA-IR) score (P for trends < 0·001). The proportion of individuals with diabetes, hypertension increased as the GGT quartile increased (P for trends < 0·001). Age-adjusted mean baPWV increased gradually in both males and females according to GGT quartiles (P for trends < 0·001 in both genders). The odds for higher baPWV (i.e. >75th percentile in each sex) were significantly higher in the highest compared with the lowest GGT quartiles, after adjustment for confounding variables, in both men [odds ratio (OR) = 1·63, 95% CI = 1·21-2·20] and women (OR = 1·56, 95% CI = 1·08-2·27).

CONCLUSIONS

These results suggest that GGT is independently associated with the increased level of arterial stiffness both in men and in women and the association between them appears to be stronger in men compared to women.

Vaspin protects vascular endothelial cells against free fatty acid-induced apoptosis through a phosphatidylinositol 3-kinase/Akt pathway

Vaspin, an adipocytokine recently identified in a rat model of type 2 diabetes, has been suggested to have an insulin-sensitizing effect. However, the exact mechanism underlying this action has not been fully elucidated. Furthermore, the specific function of vaspin is largely unknown, especially in vascular cells. We examined whether vaspin affects the insulin-signaling pathway in cultured endothelial cells and is capable of preventing free fatty acid (FFA)-induced apoptosis in endothelial cells through its insulin sensitizing effect, specifically, through its stimulatory effect on PI3-kinase/Akt signaling pathways. Vaspin significantly increased Akt phosphorylation and prevented the impairment of Akt phosphorylation by linoleic acid (LA) in insulin-stimulated endothelial cells, which effects were abolished by pretreatment with the PI3-kinase inhibitor, Wortmannin. Moreover, pretreatment with vaspin prevented LA-induced apoptosis in insulin-stimulated endothelial cells; this anti-apoptotic effect of vaspin was also eliminated by pretreatment with Wortmannin. The present study indicates that vaspin protects vascular endothelial cells from FFA-induced apoptosis through upregulation of the PI3-kinase/Akt signaling pathway. Our study is the first to demonstrate that vascular cells can be targets of vaspin. Our results further suggest that vaspin could have beneficial effects on the atherosclerosis.

Progression to insulin deficiency in Korean patients with Type 2 diabetes mellitus positive for anti-GAD antibody

AIMS

To investigate the rate of progression to insulin deficiency in Korean patients with Type 2 diabetes mellitus positive for anti-GAD antibody (GADA) and to determine the factors related to progression to insulin deficiency.

METHODS

We retrospectively analysed data on 87 GADA-positive and 87 age- and sex-matched GADA-negative patients with Type 2 diabetes. GADA-positive patients were further subclassified into high-titre (≥ 250 WHO units/ml) (n = 24) and low-titre (< 250 WHO units/ml) (n = 63) subgroups. Cox proportional hazard analysis was used to identify factors associated with progression to insulin deficiency.

RESULTS

Over a period of 6 years, two of 87 (2.3%) GADA-negative and 37 of 87 (42.5%) GADA-positive patients had progressed to insulin deficiency. The rate of progression to insulin deficiency was higher in the high-titre than in the low-titre subgroup (75.0 vs. 30.2%). Multivariate analysis in GADA-positive patients showed that high-titre GADA and low BMI at diagnosis were independent factors significantly related to progression to insulin deficiency.

CONCLUSIONS

The presence of GADA predicted the progression to insulin deficiency in Korean patients with Type 2 diabetes. In GADA-positive patients, high-titre GADA and low BMI were associated with this progression.