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Increased Gluconeogenesis is One Cause of Cystic Fibrosis Related Diabetes (CFRD)

NCT00082238 · Status: COMPLETED · Phase: NA · Type: INTERVENTIONAL · Enrollment: 42

Last updated 2018-03-14

No results posted yet for this study

Summary

People with CF have a high incidence of diabetes, called CFRD. CFRD is an important cause of worsened morbidity and mortality, thus understanding the pathophysiology underlying its development is imperative. Insulin deficiency has been well recognized as one cause of CFRD; however the clinical presentation and studies of pathogenesis indicate that the etiology is more complex. There is strong evidence that normal metabolism of carbohydrate, protein and fat is altered in CF. We believe that the inflammatory response to chronic underlying lung disease is responsible for insulin resistance and alters substrate metabolism, and that these changes, in addition to insulin deficiency cause CFRD. Our global hypothesis is that hyperglycemia is caused, in part, by high rates of gluconeogenesis resulting from excessive amino acid substrate availability caused by cytokine-mediated protein catabolism. We further hypothesize that inflammation alters normal fatty acid metabolism leading to lipogenesis, an energy wasteful pathway. We will recruit 24 adult CF subjects and 10 controls (similar in distribution in lean tissue mass, age and gender) and will categorize them according to glucose tolerance (OGTT), as well as insulin secretion and insulin sensitivity using the Tolbutamide-stimulated IVGTT and the Minimal Model. Clinical status will be characterized by measuring pulmonary function and modified NIH scores, in addition to measuring levels of circulating cytokines. Gluconeogenesis (GNG) will be quantified by measuring the incorporation 2H into the 2nd, 5th and 6th carbons of glucose. Amino acid turnover rates will be measured using stable isotopes of lactate and alanine and whole body protein turnover (WBPT) will be measured using \[1-13C\]leucine and \[15N2\]urea. Fat metabolism will be evaluated by measuring ketone body turnover using stable isotopes, and by quantifying lipogenesis using the isotopomer equilibration method. Key enzymes of fatty acid metabolism will also be measured. We will utilize indirect calorimetry to measure resting energy expenditure. Subjects will be recruited from the CF centers at the University of Texas- Southwestern and the South Central CF Consortium.

Conditions

Interventions

OTHER

Stable isotopes

Stable isotopes were used to quantify gluconeogenesis GNG, hepatic glucose production (HGP), and protein breakdown.

Sponsors & Collaborators

  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

    lead NIH

Principal Investigators

  • Dana S Hardin, MD · University of Texas

Study Design

Allocation
NON_RANDOMIZED
Purpose
DIAGNOSTIC
Masking
NONE
Model
PARALLEL

Eligibility

Min Age
18 Years
Max Age
45 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2003-03-31
Primary Completion
2005-03-31
Completion
2005-03-31

Countries

  • United States

Study Locations

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Entities

Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00082238 on ClinicalTrials.gov