Article

Depletion of plasma antioxidants in surgical intensive care unit patients requiring parenteral feeding: effects of parenteral nutrition with or without alanyl-glutamine dipeptide supplementation.

Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA.
Nutrition (impact factor: 3.03). 01/2008; 24(1):37-44. DOI:10.1016/j.nut.2007.10.004 pp.37-44
Source: PubMed

ABSTRACT Antioxidant depletion is common in critically ill patients. This study was designed to determine the effects of parenteral nutrition (PN), with or without glutamine (Gln) supplementation, on systemic antioxidant status in adult patients after major surgery who required PN in the surgical intensive care unit (SICU) setting.
Fifty-nine patients in the SICU who required PN after pancreatic surgery or cardiac, vascular, or colonic (non-pancreatic) surgery were randomized in a double-blinded study to receive standard PN (Gln-free) or Gln-supplemented PN (Gln-PN) in which Gln was provided as alanyl-Gln dipeptide. Conventional PN vitamin and mineral doses were administered to all subjects. Plasma concentrations of the antioxidant glutathione (GSH) and the antioxidant nutrients alpha-tocopherol, vitamin C, and zinc were determined at baseline (initiation of study PN) and again after 7 d of study PN. Data were analyzed for the total study cohort and within the pancreatic surgery and non-pancreatic (cardiac, vascular, and colonic) surgery patient subgroups.
Mean plasma antioxidant concentrations were within or slightly below the normal ranges at baseline. However, a larger percentage of patients demonstrated below-normal baseline plasma concentrations of GSH (59%), vitamin C (59%), and zinc (68%), respectively. A smaller percentage of patients exhibited below-normal plasma alpha-tocopherol levels (21%). Study PN significantly improved plasma zinc levels in the entire study group and in each surgical subgroup. Gln-PN significantly improved the change in plasma levels of reduced GSH from baseline to day 7 in the non-pancreatic surgery patients (PN -0.27 microM versus Gln-PN +0.26 microM, P < 0.03).
Low plasma levels of key antioxidants were common in this group of patients in the SICU despite administration of PN containing conventional micronutrients. Compared with standard PN, Gln-supplemented PN improved plasma GSH levels in patients in the SICU after cardiac, vascular, or colonic operations.

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  • Article: Increased urinary zinc excretion after thermal injury.
    M G Boosalis, L D Solem, F B Cerra, F Konstantinides, D H Ahrenholz, J T McCall, C J McClain
    [show abstract] [hide abstract]
    ABSTRACT: Urinary zinc excretion normally plays a minor role in zinc homeostasis; however, urinary zinc excretion is markedly elevated after trauma or surgery, and mechanism(s) for this zinc loss are poorly defined. In this study we evaluated multiple potential mechanisms for increased urinary zinc excretion in patients with thermal injury. We documented that patients with severe thermal injury had markedly elevated urinary zinc excretion. Above 20% total body surface area burn, however, the severity of thermal injury did not correlate with urinary zinc excretion. Serum zinc concentrations were depressed on initial evaluation and gradually increased during the hospital course, whereas peak urinary zinc excretion occurred 2 to 5 weeks after injury. Thus the depression in serum zinc concentration did not temporally relate to the observed pattern of hyperzincuria. Increased urinary zinc excretion also did not temporally relate to urinary excretion of the amino acids cysteine and histidine (both of which tightly bind zinc) nor to urinary 3-methylhistidine excretion, a marker of muscle breakdown. Urinary amylase excretion, a marker of renal tubular dysfunction, did follow the pattern of urinary zinc loss to some extent, although this correlation was not perfect. Increased oral intake of zinc via zinc supplements resulted in significantly increased urinary zinc excretion. Patients receiving total parenteral nutrition (TPN) did not have significantly increased urinary zinc excretion when compared with people receiving their total nutrient intake by mouth.(ABSTRACT TRUNCATED AT 250 WORDS)
    Journal of Laboratory and Clinical Medicine 01/1992; 118(6):538-45. · 2.62 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

Antioxidant depletion
 
antioxidant glutathione
 
antioxidant nutrients alpha-tocopherol
 
Conventional PN vitamin
 
critically ill patients
 
double-blinded study
 
entire study group
 
Gln-supplemented PN
 
Low plasma levels
 
major surgery
 
mineral doses
 
non-pancreatic surgery patients
 
pancreatic surgery
 
parenteral nutrition
 
plasma GSH levels
 
plasma levels
 
plasma zinc levels
 
standard PN
 
Study PN
 
systemic antioxidant status