title: Inflammation contributes to low plasma amino acid concentrations in patients with chronic kidney disease.
abstract: BACKGROUND
  Inflammation and malnutrition are common in chronic kidney disease (CKD) patients, and plasma concentrations of free amino acids (AAs) in these patients are often abnormal. Malnutrition contributes to alterations in AA concentrations.
  
  
  OBJECTIVE
  The objective was to study the effects of inflammation on plasma AA concentrations.
  
  
  METHODS
  Concentrations of plasma AAs, serum albumin, and several inflammatory markers were analyzed in 200 fasting, nondiabetic CKD patients who were close to the start of renal replacement therapy. The nutritional status of these patients was assessed by a subjective global assessment.
  
  
  RESULTS
  The patients with inflammation [C-reactive protein (CRP) concentrations >10 mg/L] or malnutrition had lower AA concentrations than did the patients with no inflammation or malnutrition. The presence of both inflammation and malnutrition was associated with more marked reductions in AA concentrations than was malnutrition alone. Significant inverse correlations were observed between the plasma concentrations of most of the essential and nonessential AAs and inflammatory markers, whereas serum albumin concentrations were positively correlated with several AA concentrations. A stepwise multivariate regression analysis showed that serum CRP concentrations were independently associated with low concentrations of the sums of both nonessential AAs and all AAs. An analysis of all-cause mortality with a Kaplan-Meier test showed that the patients with higher AA concentrations had significantly better survival than did the patients with lower AA concentrations.
  
  
  CONCLUSIONS
  Plasma AA concentrations are low in CKD patients with inflammation and are inversely correlated with concentrations of inflammatory markers. Although inflammation and malnutrition are closely related, CRP concentrations were independently associated with low concentrations of the sums of both nonessential AAs and all AAs, which suggests an independent role of inflammation as a cause of low plasma AA concentrations in CKD patients.
authors.affiliation: Divisions of Renal Medicine and Baxter Novum, Department of Clinical Science, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: Mohammed E
authors.initials: ME
authors.lastname: Suliman
authors.forename: A Rashid
authors.initials: AR
authors.lastname: Qureshi
authors.forename: Peter
authors.initials: P
authors.lastname: Stenvinkel
authors.forename: Roberto
authors.initials: R
authors.lastname: Pecoits-Filho
authors.forename: Peter
authors.initials: P
authors.lastname: Bárány
authors.forename: Olof
authors.initials: O
authors.lastname: Heimbürger
authors.forename: Björn
authors.initials: B
authors.lastname: Anderstam
authors.forename: Ernesto
authors.initials: E
authors.lastname: Rodríguez Ayala
authors.forename: José C
authors.initials: JC
authors.lastname: Divino Filho
authors.forename: Anders
authors.initials: A
authors.lastname: Alvestrand
authors.forename: Bengt
authors.initials: B
authors.lastname: Lindholm
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000596:Amino Acids / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D002908:Chronic Disease; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007249:Inflammation / Q000097:blood*; D007674:Kidney Diseases / Q000097:blood*; D008297:Male; D008875:Middle Aged
chemical_list: D000596:Amino Acids; D002097:C-Reactive Protein