title: Arginine supplementation is well tolerated but does not enhance mitogen-induced lymphocyte proliferation in elderly nursing home residents with pressure ulcers.
abstract: BACKGROUND
  Immune function declines with age, increasing risk for infection and delaying wound healing. Arginine enhances immune function and healing of standardized wounds in healthy elderly persons. The purpose of this study was to determine what level of arginine supplementation was orally and metabolically tolerated and effective in enhancing immune function in elderly persons with pressure ulcers.
  
  
  METHODS
  Residents with one or more pressure ulcers were recruited from two local nursing homes. Subjects were randomized to receive 0 g (n = 10; age, 82 +/- 3 years), 8.5 g (n = 11; 81 +/- 3 years), or 17 g (n = 11; 87 +/- 2 years) of supplemental arginine each day for 4 weeks. Oral tolerance, ie, absence of nausea, vomiting, abdominal distention, or diarrhea, was assessed daily. Metabolic tolerance was assessed weekly by evaluating serum electrolytes. Lymphocyte proliferation to phytohemagglutinin and interleukin 2 production were measured at baseline and after 4 weeks of supplementation as indicators of immune function.
  
  
  RESULTS
  Supplemental arginine significantly increased plasma arginine levels and was orally and metabolically tolerated with no complaints of abdominal distress or no clinically relevant changes in electrolyte levels among groups. Lymphocyte proliferation and interleukin 2 production were significantly different between nursing homes. When data from nursing homes were considered individually, arginine supplementation did not enhance the proliferative response. In subjects from nursing home 2 only, there was a 38% and 75% decrease (p < .05) in lymphocyte proliferation with 8.5 and 17 g of supplemental arginine, respectively. Interleukin 2 production was no different among supplementation groups.
  
  
  CONCLUSIONS
  Pharmacologic doses of arginine were well tolerated but did not enhance lymphocyte proliferation or interleukin 2 production in nursing home residents with pressure ulcers. CLINICAL RELEVANCY: Enteral formulas supplemented with pharmacologic levels of arginine are frequently administered to elderly persons. This study demonstrates that the very old can tolerate these nitrogen loads if baseline renal function is normal and fluid intake is encouraged. Further research needs to be completed investigating the effect of arginine supplementation on immune function in this population before recommending arginine use.
authors.affiliation: Food Science and Human Nutrition, College of Agricultural and Life Sciences, University of Florida, Gainesville 32611-0370, USA. blh@gnv.ifas.ufl.edu
authors.forename: B
authors.initials: B
authors.lastname: Langkamp-Henken
authors.forename: K A
authors.initials: KA
authors.lastname: Herrlinger-Garcia
authors.forename: J K
authors.initials: JK
authors.lastname: Stechmiller
authors.forename: J A
authors.initials: JA
authors.lastname: Nickerson-Troy
authors.forename: B
authors.initials: B
authors.lastname: Lewis
authors.forename: L
authors.initials: L
authors.lastname: Moffatt
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D001120:Arginine / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D004333:Drug Administration Routes; D004573:Electrolytes / Q000097:blood; D005260:Female; D006707:Homes for the Aged; D006801:Humans; D007376:Interleukin-2 / Q000097:blood* / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D008934:Mitogens; D009735:Nursing Homes; D009752:Nutritional Status; D009952:Ornithine / Q000097:blood; D003668:Pressure Ulcer / Q000150:complications / Q000276:immunology*; D016896:Treatment Outcome
chemical_list: D004573:Electrolytes; D007376:Interleukin-2; D008934:Mitogens; D001120:Arginine; D009952:Ornithine