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.

Insulin-like growth factor type 1 (IGF-1) and IGF binding protein-3 in patients with Ewing sarcoma family of tumors

BACKGROUND

Ewing sarcoma family of tumors (ESFTs) are the second most common bone tumor, that most often affects persons ages 3-40 years. The ESFTs rely on signaling through the insulin-like growth factor-1 receptor (IGF-1R) for growth and transformation. The current studies were performed to determine the levels of IGF-1 and IGF binding protein-3 (IGFBP-3) in patients with ESFT. The authors then performed an exploratory analysis to evaluate whether IGF parameters could differentiate event free or overall survival in ESFT patients.

METHODS

The authors measured serum levels of IGF-1 and IGFBP-3 by using a radioimmunoassay from 111 patients with ESFT with a median follow-up of 13 years from diagnosis.

RESULTS

The IGF-1 levels were lower among patients with metastatic disease to the bones or the bone marrow compared with patients without metastasis to these sites (p2 = 0.021 and 0.0038, respectively). IGFBP-3 is known to sequester IGF-1; the ratios of IGFBP-3 to IGF-1 were evaluated. Patients with metastatic disease to any site had higher IGFBP-3 to IGF-1 ratios than patients with localized disease (p2 = 0.0067). There was a trend toward increased survival in patients with localized disease who had high IGFBP-3 to IGF-1 levels. Metastatic patients showed a similar trend.

CONCLUSIONS

Levels of IGF-1 and IGFBP-3 in ESFT patients can identify patients with the most widespread disease. The IGFBP-3 to IGF-1 ratio in patients with either localized or metastatic disease identified patients with a trend toward increased survival. Further prospective evaluation with higher patient numbers might show a prognostic role for the IGFBP-3 to IGF-1 ratio in patients with ESFT.

An adult with Prader-Willi syndrome and anorexia nervosa: a case report

A 39-year-old man with Prader-Willi syndrome presents for evaluation of uncontrolled weight loss. Past history was significant for gastric bypass and prior episodes of intentional dieting. Family history was significant for an alcoholic father and two siblings with anorexia nervosa. The patient was unconcerned about his weight loss despite cachexia and did not want to stop dieting. This presentation of a restrictive eating pattern in a man with a syndrome usually associated with compulsive hyperphagia is the first known report

Evaluation of the insulin resistance syndrome in 5- to 10-year-old overweight/obese African-American children

OBJECTIVE

To characterize the insulin sensitivity of overweight and obese 5- to 10-year-old (Tanner stage 1-3) African-American children screened for participation in a diabetes prevention study and to identify the association of insulin sensitivity with obesity, hyperlipidemia, and hypertension.

RESEARCH DESIGN AND METHODS

Measures of insulin resistance (homeostasis model assessment) and insulin sensitivity (Matsuda and DeFronzo's whole-body insulin sensitivity) were calculated from a 2-h oral glucose tolerance test in 137 African-American children recruited into a diabetes prevention study. Measures of lipids (LDL, HDL, total cholesterol, and triglycerides), blood pressure, and body composition were obtained for a subset of the children.

RESULTS

In response to a glucose challenge, girls and older and heavier children produced significantly more insulin. As BMI increased, there was a statistically significant decrease in insulin sensitivity, particularly in girls. Insulin sensitivity was inversely correlated with increases in blood pressure, triglycerides, subcutaneous fat, the percentage of total body fat, and Tanner stage, but it was not correlated with LDL and HDL.

CONCLUSIONS

Reduced insulin sensitivity and the cluster of risk factors known as the insulin resistance syndrome (IRS) are already apparent in these overweight African-American children. Young African-American girls, in particular, already show evidence of hyperinsulinemia in response to a glucose load, suggesting that the early stages of metabolic decompensation that lead to type 2 diabetes are already occurring. Monitoring of those risk factors known to be part of IRS should become part of routine medical care for overweight or obese African-American children.

The prevalence of celiac disease in at-risk groups of children in the United States

OBJECTIVE

In contrast to its prevalence in Europe, celiac disease (CD) is considered rare in the United States. We aimed to determine the prevalence of CD in children presenting with symptoms or conditions associated with CD.

STUDY DESIGN

Individuals aged 6 months to 20 years were screened for IgG and IgA antigliadin (AGA-IgG and AGA-IgA) and antiendomysium (EMA) antibodies. Those with only elevated AGA-IgG were screened for selective IgA deficiency. Patients with elevated EMA, or AGA-IgG elevation and selective IgA deficiency, were advised to undergo small intestinal biopsy.

RESULTS

A total of 1200 individuals were studied; 34 were EMA positive-26 (19 EMA positive) consented to biopsy and 21 had CD, giving a prevalence of 1 in 57 (21/1200). Including the 15 EMA positive patients who refused a biopsy, the prevalence of CD in this study could be as high as 1 in 33 (36/1200).

CONCLUSIONS

CD is not rare in the United States and may be as common as in Europe. AGA and EMA are useful for identifying patients who should undergo a small intestinal biopsy.

An organization-wide approach for an effective communication system, Part 2

This is the second article in a two-part series that describes an organization's approach to designing, implementing, and evaluating a communication system. Part 1 of this series, published in the March 1998 issue, focused on the design and implementation of this system. This article addresses the evaluation of outcomes related to identified goals to improve communication flow and decision making on multiple levels and to promote accountability for clinical and operational performance. Implementation strategies involving change management, emergence of issues with related implications, and planned evolution of this system also are discussed for ongoing organizational performance improvement.

An organization-wide approach for an effective communication system, Part 1

This two-part series provides a cogent discussion of designing and implementing an effective communication system, with a committee structure based on the Joint Commission on Accreditation of Health Care Organizations (JCAHO) functions. Part one includes the development and design using a systems approach. Part two, which will be published in the April 1998 issue of JONA, will address the evaluation of outcomes and implications of this communication system. The experiential learning gained from this process is illustrated by the analysis of themes that surfaced during the implementation.

Functional analysis of the rat insulin-like growth factor I gene and identification of an IGF-I gene promoter

Insulin-like growth factor I (IGF-I) mediates many of the systemic growth-promoting effects of growth hormone and also functions as a locally acting growth stimulator. In mammals, IGF-I gene expression is complicated, as the gene is transcribed and processed into multiple mRNAs (ranging in length from less than 1 to nearly 7.5 kb) that encode at least two protein precursors. As a step toward understanding the regulation of IGF-I, we report the complete organization of the rat IGF-I gene, including identification of the structural determinants for all IGF-I mRNA species, and an initial functional analysis of its promoters. The gene is composed of 6 exons distributed over nearly 80 kb of chromosomal DNA and is structurally heterogeneous. Several transcription start sites were identified within IGF-I exons 1 and 2, adjacent to presumptive promoters 1 and 2, respectively, and at least three polyadenylation sites were mapped to exon 6. To test promoter function, fusion genes were constructed linking fragments of IGF-I DNA to a reporter plasmid. Chimeric genes containing at least 395 bp of DNA from the 5'-flanking region of exon 1 enhanced luciferase activity after transfection into the IGF-I-producing SK-N-MC cell line, while fusion plasmids containing up to 1,300 bp of DNA from the 5'-flanking region of exon 2 were inactive. Relative levels of IGF-I mRNAs containing exons 1 or 2 varied among different rat tissues, although in response to acute or chronic growth hormone treatment both classes of transcripts were induced coordinately in rat liver. These observations represent the first thorough characterization of a mammalian IGF-I gene, and provide a starting point for defining the mechanisms by which growth hormone and other trophic factors regulate IGF-I gene expression.