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Am J Clin Nutr. 2016 Jun;103(6):1458-64. doi: 10.3945/ajcn.115.125187. Epub 2016 May 4.

Alterations in whole-body arginine metabolism in chronic obstructive pulmonary disease.

Author information

1
Center for Translational Research in Aging and Longevity, Department of Health and Kinesiology, Texas A&M University, College Station, TX; and Departments of Geriatrics and.
2
Center for Translational Research in Aging and Longevity, Department of Health and Kinesiology, Texas A&M University, College Station, TX; and Departments of Geriatrics and nep.deutz@ctral.org.
3
Pulmonary and Critical Care Medicine, University of Arkansas for Medical Sciences, Little Rock, AR.

Abstract

BACKGROUND:

Chronic obstructive pulmonary disease (COPD) is a condition characterized by systemic low-grade inflammation that could increase the production of nitric oxide (NO), of which arginine is the sole precursor. Arginine is derived from the breakdown of protein and through the conversion of citrulline to arginine (de novo arginine production).

OBJECTIVE:

Our objective was to study whole-body arginine and citrulline and related metabolism in stable COPD patients.

DESIGN:

With the use of stable isotope methodology, we studied whole-body arginine and citrulline rates of appearance, de novo arginine (citrulline-to-arginine flux) and NO (arginine-to-citrulline flux) production, protein synthesis and breakdown rates, and plasma amino acid concentrations in a heterogeneous group of patients with moderate-to-severe COPD [n = 23, mean ± SE age: 65 ± 2 y, forced expiratory volume in 1 s (FEV1): 40% ± 2% of predicted], and a group of healthy older adults (n = 19, mean ± SE age: 64 ± 2 y, FEV1: 95% ± 4% of predicted).

RESULTS:

Although plasma arginine and citrulline concentrations were comparable between COPD patients and controls, whole-body arginine (P = 0.015) and citrulline (P = 0.026) rates of appearance were higher in COPD patients and related to a 57% greater de novo arginine production (P < 0.0001). Despite a higher whole-body arginine clearance in COPD patients (P < 0.0001), we found no difference in NO production.

CONCLUSION:

In stable patients with moderate-to-severe COPD, endogenous arginine production is upregulated to support a higher arginine utilization that is unrelated to whole-body NO production. This trial was registered at clinicaltrials.gov as NCT01173354 and NCT01172314.

KEYWORDS:

COPD; arginine; citrulline; nitric oxide; protein breakdown

PMID:
27146652
PMCID:
PMC4880996
DOI:
10.3945/ajcn.115.125187
[Indexed for MEDLINE]
Free PMC Article

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