title: Acquired Amino Acid Deficiencies: A Focus on Arginine and Glutamine.
abstract: Nonessential amino acids are synthesized de novo and therefore not diet dependent. In contrast, essential amino acids must be obtained through nutrition since they cannot be synthesized internally. Several nonessential amino acids may become essential under conditions of stress and catabolic states when the capacity of endogenous amino acid synthesis is exceeded. Arginine and glutamine are 2 such conditionally essential amino acids and are the focus of this review. Low arginine bioavailability plays a pivotal role in the pathogenesis of a growing number of varied diseases, including sickle cell disease, thalassemia, malaria, acute asthma, cystic fibrosis, pulmonary hypertension, cardiovascular disease, certain cancers, and trauma, among others. Catabolism of arginine by arginase enzymes is the most common cause of an acquired arginine deficiency syndrome, frequently contributing to endothelial dysfunction and/or T-cell dysfunction, depending on the clinical scenario and disease state. Glutamine, an arginine precursor, is one of the most abundant amino acids in the body and, like arginine, becomes deficient in several conditions of stress, including critical illness, trauma, infection, cancer, and gastrointestinal disorders. At-risk populations are discussed together with therapeutic options that target these specific acquired amino acid deficiencies.
authors.affiliation: 1 Department of Pediatrics, Division of Pediatric Emergency Medicine, Emory-Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, Georgia, USA.
authors.forename: Claudia R
authors.initials: CR
authors.lastname: Morris
authors.affiliation: 2 Department of Dietetics and Nutrition, University of Kansas, Kansas City, Kansas, USA.
authors.forename: Jill
authors.initials: J
authors.lastname: Hamilton-Reeves
authors.affiliation: 3 Department of Surgery, Oregon Health and Science University, Portland, Oregon, USA.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Martindale
authors.affiliation: 4 Department of Medicine, Division of Nephrology, Northshore University Health System, University of Chicago, Chicago, Illinois, USA.
authors.forename: Menaka
authors.initials: M
authors.lastname: Sarav
authors.affiliation: 5 Nestlé HealthCare Nutrition, Inc, Florham Park, New Jersey, USA.
authors.forename: Juan B
authors.initials: JB
authors.lastname: Ochoa Gautier
mesh_terms: D001120:Arginine / Q000172:deficiency*; D016638:Critical Illness; D005973:Glutamine / Q000172:deficiency*; D006801:Humans
chemical_list: D005973:Glutamine; D001120:Arginine
keywords: arginase; arginine; essential amino acids; glutamine; hemolysis; myeloid-derived suppressor cells; sickle cell disease; trauma