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1.  Parallel Workflow for High-Throughput (>1,000 Samples/Day) Quantitative Analysis of Human Insulin-Like Growth Factor 1 Using Mass Spectrometric Immunoassay 
PLoS ONE  2014;9(3):e92801.
Insulin-like growth factor 1 (IGF1) is an important biomarker for the management of growth hormone disorders. Recently there has been rising interest in deploying mass spectrometric (MS) methods of detection for measuring IGF1. However, widespread clinical adoption of any MS-based IGF1 assay will require increased throughput and speed to justify the costs of analyses, and robust industrial platforms that are reproducible across laboratories. Presented here is an MS-based quantitative IGF1 assay with performance rating of >1,000 samples/day, and a capability of quantifying IGF1 point mutations and posttranslational modifications. The throughput of the IGF1 mass spectrometric immunoassay (MSIA) benefited from a simplified sample preparation step, IGF1 immunocapture in a tip format, and high-throughput MALDI-TOF MS analysis. The Limit of Detection and Limit of Quantification of the resulting assay were 1.5 μg/L and 5 μg/L, respectively, with intra- and inter-assay precision CVs of less than 10%, and good linearity and recovery characteristics. The IGF1 MSIA was benchmarked against commercially available IGF1 ELISA via Bland-Altman method comparison test, resulting in a slight positive bias of 16%. The IGF1 MSIA was employed in an optimized parallel workflow utilizing two pipetting robots and MALDI-TOF-MS instruments synced into one-hour phases of sample preparation, extraction and MSIA pipette tip elution, MS data collection, and data processing. Using this workflow, high-throughput IGF1 quantification of 1,054 human samples was achieved in approximately 9 hours. This rate of assaying is a significant improvement over existing MS-based IGF1 assays, and is on par with that of the enzyme-based immunoassays. Furthermore, a mutation was detected in ∼1% of the samples (SNP: rs17884626, creating an A→T substitution at position 67 of the IGF1), demonstrating the capability of IGF1 MSIA to detect point mutations and posttranslational modifications.
doi:10.1371/journal.pone.0092801
PMCID: PMC3963945  PMID: 24664114
2.  Pioglitazone slows progression of atherosclerosis in prediabetes independent of changes in cardiovascular risk factors 
Objective
To determine whether changes in standard and novel risk factors during the ACT NOW trial explained the slower rate of CIMT progression with pioglitazone treatment in persons with prediabetes.
Methods and Results
CIMT was measured in 382 participants at the beginning and up to three additional times during follow-up of the ACT NOW trial. During an average follow-up of 2.3 years, the mean unadjusted annual rate of CIMT progression was significantly (P=0.01) lower with pioglitazone treatment (4.76 × 10−3 mm/year, 95% CI, 2.39 × 10−3 – 7.14 × 10−3 mm/year) compared with placebo (9.69 × 10−3 mm/year, 95% CI, 7.24 × 10−3 – 12.15 × 10−3 mm/year). High-density lipoprotein cholesterol, fasting and 2-hour glucose, HbA1c, fasting insulin, Matsuda insulin sensitivity index, adiponectin and plasminogen activator inhibitor-1 levels improved significantly with pioglitazone treatment compared with placebo (P < 0.001). However, the effect of pioglitazone on CIMT progression was not attenuated by multiple methods of adjustment for traditional, metabolic and inflammatory risk factors and concomitant medications, and was independent of changes in risk factors during pioglitazone treatment.
Conclusions
Pioglitazone slowed progression of CIMT, independent of improvement in hyperglycemia, insulin resistance, dyslipidemia and systemic inflammation in prediabetes. These results suggest a possible direct vascular benefit of pioglitazone.
doi:10.1161/ATVBAHA.112.300346
PMCID: PMC3908828  PMID: 23175674
Carotid atherosclerosis progression; Impaired glucose tolerance; Insulin resistance; Inflammation; Pioglitazone
3.  Progression of Vascular Calcification Is Increased With Statin Use in the Veterans Affairs Diabetes Trial (VADT) 
Diabetes Care  2012;35(11):2390-2392.
OBJECTIVE
To determine the effect of statin use on progression of vascular calcification in type 2 diabetes (T2DM).
RESEARCH DESIGN AND METHODS
Progression of coronary artery calcification (CAC) and abdominal aortic artery calcification (AAC) was assessed according to the frequency of statin use in 197 participants with T2DM.
RESULTS
After adjustment for baseline CAC and other confounders, progression of CAC was significantly higher in more frequent statin users than in less frequent users (mean ± SE, 8.2 ± 0.5 mm3 vs. 4.2 ± 1.1 mm3; P < 0.01). AAC progression was in general not significantly increased with more frequent statin use; in a subgroup of participants initially not receiving statins, however, progression of both CAC and AAC was significantly increased in frequent statin users.
CONCLUSIONS
More frequent statin use is associated with accelerated CAC in T2DM patients with advanced atherosclerosis.
doi:10.2337/dc12-0464
PMCID: PMC3476911  PMID: 22875226
4.  Rates and Determinants of Coronary and Abdominal Aortic Artery Calcium Progression in the Veterans Affairs Diabetes Trial (VADT) 
Diabetes Care  2010;33(12):2642-2647.
OBJECTIVE
To determine the predictors of progression of calcified atherosclerosis and the effect of intensive glycemic control on this process in patients with type 2 diabetes.
RESEARCH DESIGN AND METHODS
As part of the Risk Factors, Atherosclerosis, and Clinical Events in Diabetes (RACED) substudy of the Veterans Affairs Diabetes Trial (VADT), 197 and 189 individuals with type 2 diabetes received baseline and follow-up computed tomographic scans for measurement of coronary and abdominal artery calcium, respectively. Standard and novel risk factors were assessed at baseline, and progression of calcified atherosclerosis was determined by several methods. Progression was defined both as a categorical (square root increase of volumetric scores ≥2.5 mm3) and continuous variable. In addition, annualized percent change of volume scores was determined.
RESULTS
After an average follow-up of 4.6 years, >75% of individuals demonstrated coronary (CAC) and abdominal artery calcification (AAC) progression. Progression increased with higher baseline calcium categories but was not influenced by standard risk factors. However, the albumin-to-creatinine ratio (ACR) (P = 0.02) and lipoprotein-associated phospholipase A2 (Lp-PLA2) (P = 0.01) predicted progression of CAC, and these results were not altered by adjustment for age and other traditional risk factors. Treatment assignment (intensive versus standard) within the VADT did not influence CAC or AAC progression, irrespective of baseline calcium category.
CONCLUSIONS
In patients with long-standing type 2 diabetes, baseline CAC, Lp-PLA2, and ACR predicted progression of CAC. Intensive glycemic control during the VADT did not reduce progression of calcified atherosclerosis.
doi:10.2337/dc10-1388
PMCID: PMC2992205  PMID: 20807873
5.  Postprandial hyperlipidemia, endothelial dysfunction and cardiovascular risk: focus on incretins 
Cardiovascular disease (CVD) risk in type 2 diabetes (T2DM) is only partially reduced by intensive glycemic control. Diabetic dyslipidemia is suggested to be an additional important contributor to CVD risk in T2DM. Multiple lipid lowering medications effectively reduce fasting LDL cholesterol and triglycerides concentrations and several of them routinely reduce CVD risk. However, in contemporary Western societies the vasculature is commonly exposed to prolonged postprandial hyperlipidemia. Metabolism of these postprandial carbohydrates and lipids yields multiple proatherogenic products. Even a transient increase in these factors may worsen vascular function and induces impaired endothelial dependent vasodilatation, a predictor of atherosclerosis and future cardiovascular events. There is a recent increased appreciation for the role of gut-derived incretin hormones in controlling the postprandial metabolic milieu. Incretin-based medications have been developed and are now used to control postprandial hyperglycemia in T2DM. Recent data indicate that these medications may also have profound effects on postprandial lipid metabolism and may favorably influence several cardiovascular functions. This review discusses (1) the postprandial state with special emphasis on postprandial lipid metabolism and its role in endothelial dysfunction and cardiovascular risk, (2) the ability of incretins to modulate postprandial hyperlipidemia and (3) the potential of incretin-based therapeutic strategies to improve vascular function and reduce CVD risk.
doi:10.1186/1475-2840-10-61
PMCID: PMC3184260  PMID: 21736746
6.  Improvement of Postprandial Endothelial Function After a Single Dose of Exenatide in Individuals With Impaired Glucose Tolerance and Recent-Onset Type 2 Diabetes 
Diabetes Care  2010;33(5):1028-1030.
OBJECTIVE
Endothelial dysfunction is frequently present in individuals with insulin resistance or type 2 diabetes and can be induced by high-fat or high-carbohydrate meals. Because exenatide reduces postprandial glucose and lipid excursions, we hypothesized that it may also improve postprandial endothelial function.
RESEARCH DESIGN AND METHODS
In a double-blinded randomized crossover design, postprandial endothelial function was examined in 28 individuals with impaired glucose tolerance or recent-onset type 2 diabetes after a single injection of exenatide or placebo given just before a high-fat meal. Endothelial function was determined with peripheral arterial tonometry pre- and postprandially.
RESULTS
Postprandial endothelial function was higher after exenatide compared with placebo (P = 0.0002). In the placebo phase, postprandial change in endothelial function was inversely associated with mean postprandial concentrations of triglycerides (r = −0.62, P = 0.0004). Changes in postprandial triglyceride concentrations explained 64% of exenatide's effect on postprandial endothelial function.
CONCLUSIONS
Exenatide ameliorates postprandial endothelial dysfunction after a high-fat meal.
doi:10.2337/dc09-1961
PMCID: PMC2858168  PMID: 20200309
7.  Hepatic Fat and Inflammation in Type 2 Diabetes 
Although the association between inflammation and hepatic fat is fairly established, it remains unclear whether this association is independent of general measures of obesity and standard cardiovascular risk factors. Therefore, the aim of this study was to investigate the contribution of hepatic steatosis (HS) as an independent predictor of chronic inflammation in 281 subjects with type 2 diabetes. Hepatic steatosis significantly (p < 0.01) correlated with CRP (r= −0.16) and adiponectin (r=0.23). The association of HS with both CRP and adiponectin remained significant after adjustment for age, ethnicity, BMI (or WC), triglycerides, HDL, and total cholesterol. These data support the concept that accumulation of hepatic fat is related to enhanced inflammation in type 2 diabetes, independent of general measures of obesity and standard cardiovascular risk factors.
doi:10.1016/j.metabol.2009.07.041
PMCID: PMC2823936  PMID: 19850309
8.  Intensive Glucose-Lowering Therapy Reduces Cardiovascular Disease Events in Veterans Affairs Diabetes Trial Participants With Lower Calcified Coronary Atherosclerosis 
Diabetes  2009;58(11):2642-2648.
OBJECTIVE
This study investigated the hypothesis that baseline calcified coronary atherosclerosis may determine cardiovascular disease events in response to intensive glycemic control within the Veterans Affairs Diabetes Trial (VADT).
RESEARCH DESIGN AND METHODS
At baseline, 301 type 2 diabetic participants in the VADT, a randomized trial comparing the effects of intensive versus standard glucose lowering on cardiovascular events, had baseline coronary atherosclerosis assessed by coronary artery calcium (CAC) measured by computed tomography. Participants were followed over the 7.5-year study for development of cardiovascular end points.
RESULTS
During a median follow-up duration of 5.2 years, 89 cardiovascular events occurred. Although intensive glucose-lowering therapy did not significantly reduce cardiovascular events in the substudy cohort as a whole, there was evidence that the response was modified by baseline CAC, as indicated by significant P values for treatment by log(CAC + 1) interaction terms in unadjusted and multivariable-adjusted models (0.01 and 0.03, respectively). Multivariable-adjusted hazard ratios (HRs) for the effect of treatment indicated a progressive diminution of benefit with increasing CAC. Subgroup analyses were also conducted for clinically relevant CAC categories: those above and below an Agatston score of 100. Among those randomized to intensive treatment, for the subgroup with CAC >100, 11 of 62 individuals had events, while only 1 of 52 individuals with CAC ≤100 had an event. The multivariable HR for intensive treatment for those with CAC >100 was 0.74 (95% CI 0.46–1.20; P = 0.21), while for the subgroup with CAC ≤100, the corresponding HR was 0.08 (0.008–0.77; P = 0.03), with event rates of 39 and 4 per 1,000 person-years, respectively.
CONCLUSIONS
These data indicate that intensive glucose lowering reduces cardiovascular events in those with less extensive calcified coronary atherosclerosis.
doi:10.2337/db09-0618
PMCID: PMC2768182  PMID: 19651816
9.  Association Between IL-6 and the extent of Coronary Atherosclerosis in The Veterans Affairs Diabetes Trial (VADT) 
Atherosclerosis  2008;203(2):610-614.
Aims
The aim of the present study was to investigate the association of high sensitivity CRP, interleukin-6 (IL-6) and lipoprotein-associated phospholipase A2 (Lp-PLA2) with the extent of calcified coronary atherosclerosis in patients with type 2 diabetes mellitus (T2DM).
Materials and results
This is a cross-sectional study of 306 subjects aged 40 years or older who were enrolled into the Veterans Affair Diabetes Trial. Calcified coronary atherosclerosis was assessed using electron beam computed tomography scored by the Agatston method. Clinical parameters, traditional cardiovascular risk factors and plasma levels of CRP, IL-6 and Lp-PLA2 were measured at the time of the scan. Coronary artery calcium scores (CAC) increased stepwise across increasing categories of IL-6, but did not change across increasing categories of CRP and Lp-PLA2. After adjustment for traditional cardiovascular risk factors, IL-6 was significantly associated with CAC scores (p= 0.05). The association between IL-6 and CAC was largely in those with lower (below the median) abdominal artery calcium (AAC) levels (p= 0.03).
Conclusions
Despite a generally higher level of systemic inflammation in T2DM, the inflammatory marker IL-6 remained significantly associated with CAC score, particularly in those subjects with lower AAC scores.
doi:10.1016/j.atherosclerosis.2008.07.031
PMCID: PMC2688903  PMID: 18804762
Inflammatory markers; Type 2 Diabetes; Atherosclerosis; Vascular calcification; CAC; AAC
10.  Actos Now for the prevention of diabetes (ACT NOW) study 
Background
Impaired glucose tolerance (IGT) is a prediabetic state. If IGT can be prevented from progressing to overt diabetes, hyperglycemia-related complications can be avoided. The purpose of the present study was to examine whether pioglitazone (ACTOS®) can prevent progression of IGT to type 2 diabetes mellitus (T2DM) in a prospective randomized, double blind, placebo controlled trial.
Methods/Design
602 IGT subjects were identified with OGTT (2-hour plasma glucose = 140–199 mg/dl). In addition, IGT subjects were required to have FPG = 95–125 mg/dl and at least one other high risk characteristic. Prior to randomization all subjects had measurement of ankle-arm blood pressure, systolic/diastolic blood pressure, HbA1C, lipid profile and a subset had frequently sampled intravenous glucose tolerance test (FSIVGTT), DEXA, and ultrasound determination of carotid intima-media thickness (IMT). Following this, subjects were randomized to receive pioglitazone (45 mg/day) or placebo, and returned every 2–3 months for FPG determination and annually for OGTT. Repeat carotid IMT measurement was performed at 18 months and study end. Recruitment took place over 24 months, and subjects were followed for an additional 24 months. At study end (48 months) or at time of diagnosis of diabetes the OGTT, FSIVGTT, DEXA, carotid IMT, and all other measurements were repeated.
Primary endpoint is conversion of IGT to T2DM based upon FPG ≥ 126 or 2-hour PG ≥ 200 mg/dl. Secondary endpoints include whether pioglitazone can: (i) improve glycemic control (ii) enhance insulin sensitivity, (iii) augment beta cell function, (iv) improve risk factors for cardiovascular disease, (v) cause regression/slow progression of carotid IMT, (vi) revert newly diagnosed diabetes to normal glucose tolerance.
Conclusion
ACT NOW is designed to determine if pioglitazone can prevent/delay progression to diabetes in high risk IGT subjects, and to define the mechanisms (improved insulin sensitivity and/or enhanced beta cell function) via which pioglitazone exerts its beneficial effect on glucose metabolism to prevent/delay onset of T2DM.
Trial Registration
clinical trials.gov identifier: NCT00220961
doi:10.1186/1472-6823-9-17
PMCID: PMC2725044  PMID: 19640291

Results 1-10 (10)