Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Subtle in-scanner motion biases automated measurement of brain anatomy from in vivo MRI

While the potential for small amounts of motion in functional magnetic resonance imaging (fMRI) scans to bias the results of functional neuroimaging studies is well appreciated, the impact of in-scanner motion on morphological analysis of structural MRI is relatively under-studied. Even among "good quality" structural scans, there may be systematic effects of motion on measures of brain morphometry. In the present study, the subjects' tendency to move during fMRI scans, acquired in the same scanning sessions as their structural scans, yielded a reliable, continuous estimate of in-scanner motion. Using this approach within a sample of 127 children, adolescents, and young adults, significant relationships were found between this measure and estimates of cortical gray matter volume and mean curvature, as well as trend-level relationships with cortical thickness. Specifically, cortical volume and thickness decreased with greater motion, and mean curvature increased. These effects of subtle motion were anatomically heterogeneous, were present across different automated imaging pipelines, showed convergent validity with effects of frank motion assessed in a separate sample of 274 scans, and could be demonstrated in both pediatric and adult populations. Thus, using different motion assays in two large non-overlapping sets of structural MRI scans, convergent evidence showed that in-scanner motion-even at levels which do not manifest in visible motion artifact-can lead to systematic and regionally specific biases in anatomical estimation. These findings have special relevance to structural neuroimaging in developmental and clinical datasets, and inform ongoing efforts to optimize neuroanatomical analysis of existing and future structural MRI datasets in non-sedated humans. Hum Brain Mapp 37:2385-2397, 2016. © 2016 Wiley Periodicals, Inc.

Improved corpus callosum area measurements by analysis of adjoining parasagittal slices

The corpus callosum (CC) is a bundle of approximately 180 million axons connecting homologous areas of the left and right cerebral cortex. Because CC projections are topographically organized, regional CC morphological abnormalities may reflect regional cortical developmental abnormalities. We assess the variance characteristics of three CC area measurement techniques by comparing a single midsagittal slice versus three slices (midsagittal plus one parasagittal on each side) and five slices (midsagittal plus two parasagittal on each side). CC images were partitioned into five subregions using the Hofer-Frahm scheme under the three methods and variance was examined via two complementary data sets. In the first, to control for intersubject variability, 12 scans were acquired from a single subject over the course of 3 h. In the second, we used scans from 56 healthy male volunteers between the ages of 10 and 27 years (mean=17.47, S.D.=3.42). Increasing the number of slices from one to three to five diminished the coefficient of variation (CV) within subregions and increased the power to detect differences between groups. A power analysis was conducted for the sample under each method to determine the sample size necessary to discern a given percent change (delta) ranging from 1 to 20% iteratively.

Patterns of coordinated anatomical change in human cortical development: a longitudinal neuroimaging study of maturational coupling

Understanding of human structural brain development has rapidly advanced in recent years, but remains fundamentally "localizational" in nature. Here, we use 376 longitudinally acquired structural brain scans from 108 typically developing adolescents to conduct the first study of coordinated anatomical change within the developing cortex. Correlation in rates of anatomical change was regionally heterogeneous, with fronto-temporal association cortices showing the strongest and most widespread maturational coupling with other cortical areas, and lower-order sensory cortices showing the least. Canonical cortical systems with rich structural and functional interconnectivity showed significantly elevated maturational coupling. Evidence for sexually dimorphic maturational coupling was found within a frontopolar-centered prefrontal system involved in complex decision-making. By providing the first link between cortical connectivity and the coordination of cortical development, we reveal a hitherto unseen property of healthy brain maturation, which may represent a target for neurodevelopmental disease processes, and a substrate for sexually dimorphic behavior in adolescence.

Developmental trajectories of the corpus callosum in attention-deficit/hyperactivity disorder

BACKGROUND

It was recently found that the development of typical patterns of prefrontal, but not posterior, cortical asymmetry is disrupted in right-handed youth with attention-deficit/hyperactivity disorder (ADHD). Using longitudinal data, we tested the hypothesis that there would be a congruent disruption in the growth of the anterior corpus callosum, which contains white matter tracts connecting prefrontal cortical regions.

METHODS

Areas of five subregions of the corpus callosum were quantified using a semiautomated method from 828 neuroanatomic magnetic resonance scans acquired from 236 children and adolescents with ADHD (429 scans) and 230 typically developing youth (399 scans), most of whom had repeated neuroimaging. Growth rates of each diagnostic group were defined using mixed-model linear regression.

RESULTS

Right-handed participants with ADHD showed a significantly higher rate of growth in the anterior-most region of the corpus callosum (estimated annual increase in area of .97%, SEM .12%) than their typically developing peers (annual increase in area of .32% SEM .13%; t = 3.64, p = .0003). No significant diagnostic differences in growth rates were found in any other regions in right-handed participants, and no significant diagnostic differences were found in non-right-handed participants.

CONCLUSIONS

As hypothesized, we found anomalous growth trajectories in the anterior corpus callosum in ADHD. This disrupted anterior callosal growth may reflect, or even drive, the previously reported disruption in the development of prefrontal cortex asymmetry. The finding documents the dynamic, age-dependent nature of callosal and congruent prefrontal cortical abnormalities characterizing ADHD.

A critical pathway for management of patients with acute chest pain who are at low risk for myocardial ischemia: recommendations and potential impact

BACKGROUND

Use of resources for patients with acute chest pain may be improved with clinical strategies that integrate research, Bayesian analysis, and expert opinion.

OBJECTIVES

To 1) develop a critical pathway for management of patients with acute chest pain who are at low risk for complications of ischemic heart disease and 2) assess the potential effects of implementation of the pathway on patient safety and resource use.

DESIGN

Evidence-based consensus and prospective cohort study.

SETTING

Urban teaching hospital.

PATIENTS

Patients at least 30 years of age who were seen in the emergency department for chest pain and who did not have a history of trauma or abnormalities on radiologic study.

INTERVENTION

Physician-opinion leaders defined criteria for patient inclusion in the pathway and for remaining on the pathway after 6 or 12 hours of observation. Criteria were defined for appropriateness of direct admission, direct discharge, or 6 hours of observation followed by exercise treadmill testing.

MEASUREMENTS

Number of patients admitted to the hospital, number of days that patients were hospitalized, and clinical outcome.

RESULTS

2898 of 4585 patients (63%) were admitted to the hospital; of the 2898, 1152 (40%) were classified as potentially eligible for the pathway and 1068 (93%) had a benign clinical course during the initial observation period. The 1068 patients had a mean length of stay of 2.8 +/- 4.8 days. If 47% of these patients had been discharged after observation and exercise testing, implementation of the pathway would have reduced the number of admissions by 505 (17%) and days of hospitalization by 1407 (11%).

CONCLUSIONS

Retrospective analysis suggests that a critical pathway for patients with acute chest pain may substantially reduce resource use. Prospective study is needed to ensure increased efficiency without increased adverse outcomes.

Home-based Health Risk Appraisal and screening program

In an effort to improve Health Risk Appraisals and to induce individuals to change their lifestyles, comprehensive evaluations and counseling sessions were carried out for 476 participants of an experimental preventive care program (1984). Nurse practitioners interviewed participants in their homes and collected information about their lifestyle, medical history, and family history. In addition, physical examinations were performed and blood samples were obtained for laboratory analysis. This information was used to formulate health risk profiles for all participants who were then counseled on how to decrease identified health risks. Interventions included education about health risks and specific programs which were administered to help modify high-risk behaviors. At one year follow-up, significant risk reductions were reported in many areas of increased risk.