title: Leucine disposal rate for assessment of amino acid metabolism in maintenance hemodialysis patients.
abstract: BACKGROUND
  Protein energy wasting (PEW) is common in patients undergoing maintenance hemodialysis (MHD) and closely associated with poor outcomes. Insulin resistance and associated alterations in amino acid metabolism are potential pathways leading to PEW. We hypothesized that the measurement of leucine disposal during a hyperinsulinemic- euglycemic-euaminoacidemic clamp (HEAC) procedure would accurately measure the sensitivity to insulin for its actions on concomitant carbohydrate and protein metabolism in MHD patients.
  
  
  METHODS
  We examined 35 MHD patients and 17 control subjects with normal kidney function by hyperinsulinemic-euglycemic clamp (HEGC) followed by HEAC clamp procedure to obtain leucine disposal rate (LDR) along with isotope tracer methodology to assess whole body protein turnover.
  
  
  RESULTS
  The glucose disposal rate (GDR) by HEGC was 5.1 ± 2.1 mg/kg/min for the MHD patients compared to 6.3 ± 3.9 mg/kg/min for the controls (p= 0.38). The LDR during HEAC was 0.09 ± 0.03 mg/kg/min for the MHD patients compared to 0.11 ± 0.05 mg/kg/min for the controls (p= 0.009). The LDR level was correlated with whole body protein synthesis (r= 0.25;p= 0.08), with whole body protein breakdown (r= -0.38p= 0.01) and net protein balance (r= 0.85;p< 0.001) in the overall study population. Correlations remained significant in subgroup analysis. The GDR derived by HEGC and LDR correlated well in the controls (r= 0.79,p< 0.001), but less so in the MHD patients (r= 0.58,p< 0.001).
  
  
  CONCLUSIONS
  Leucine disposal rate reliably measures amino acid utilization in MHD patients and controls in response to high dose insulin.
authors.affiliation: Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN, USA (GBD, SMD, FS, CB, JTK, CDE, TAI); Vanderbilt Center for Kidney Disease, Nashville, TN, USA.
authors.forename: Gerald B
authors.initials: GB
authors.lastname: Denny
authors.affiliation: Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN, USA (GBD, SMD, FS, CB, JTK, CDE, TAI); CSRD&D, Veterans Administration Tennessee Valley Healthcare System, Nashville, TN, USA; Vanderbilt Center for Kidney Disease, Nashville, TN, USA.
authors.forename: Serpil M
authors.initials: SM
authors.lastname: Deger
authors.affiliation: Vanderbilt Center for Kidney Disease, Nashville, TN, USA; Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Guanhua
authors.initials: G
authors.lastname: Chen
authors.affiliation: Vanderbilt Center for Kidney Disease, Nashville, TN, USA; Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Aihua
authors.initials: A
authors.lastname: Bian
authors.affiliation: Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN, USA (GBD, SMD, FS, CB, JTK, CDE, TAI); Vanderbilt Center for Kidney Disease, Nashville, TN, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Sha
authors.affiliation: Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN, USA (GBD, SMD, FS, CB, JTK, CDE, TAI); CSRD&D, Veterans Administration Tennessee Valley Healthcare System, Nashville, TN, USA; Vanderbilt Center for Kidney Disease, Nashville, TN, USA.
authors.forename: Cindy
authors.initials: C
authors.lastname: Booker
authors.affiliation: Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN, USA (GBD, SMD, FS, CB, JTK, CDE, TAI); Vanderbilt Center for Kidney Disease, Nashville, TN, USA.
authors.forename: Jaclyn T
authors.initials: JT
authors.lastname: Kesler
authors.affiliation: University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
authors.forename: Sthuthi
authors.initials: S
authors.lastname: David
authors.affiliation: Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN, USA (GBD, SMD, FS, CB, JTK, CDE, TAI); Vanderbilt Center for Kidney Disease, Nashville, TN, USA.
authors.forename: Charles D
authors.initials: CD
authors.lastname: Ellis
authors.affiliation: Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN, USA (GBD, SMD, FS, CB, JTK, CDE, TAI); CSRD&D, Veterans Administration Tennessee Valley Healthcare System, Nashville, TN, USA; Vanderbilt Center for Kidney Disease, Nashville, TN, USA.
authors.forename: T Alp
authors.initials: TA
authors.lastname: Ikizler
keywords: Glucose disposal rate; Insulin resistance; Leucine disposal rate; Maintenance hemodialysis; Protein energy wasting