title: Protein turnover, lipolysis, and endogenous hormonal secretion in critically ill children.
abstract: OBJECTIVE
  The catabolic state is a major contributor to morbidity and mortality of critical illness and may be related to endocrine changes. We studied whether protein and lipid turnover correlate with insulin and growth and thyroid hormone plasma levels in critically ill infants.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Pediatric intensive care unit.
  
  
  METHODS
  Twelve critically ill children and ten age-matched controls.
  
  
  METHODS
  We measured lipolysis and protein turnover by infusing albumin-bound uniformly 13C palmitic acid and 2H3-leucine for 3 hrs and 2H5-glycerol for 5 hrs to critically ill infants. Simultaneously, we measured serum growth hormones, insulin, C-peptide, thyroid-stimulating hormone, T4, T3, albumin, retinol binding protein (RBP), and prealbumin. Hormone and serum protein levels were also measured in six children when recovered from critical illness. Ten healthy age-matched children served as controls for hormone serum levels comparison.
  
  
  RESULTS
  Palmitic acid and glycerol turnover were 5.6 +/- 2.2 micromol/kg/min and 12.2 +/- 7.3 micromol/kg/min, respectively, whereas alpha-ketoisocaproic turnover was 4.9 +/- 2.8 micromol/kg/min. Alpha-ketoisocaproic turnover positively correlated (R = 0.7, p = .03) with duration of pediatric intensive care unit admission and with prealbumin and RBP serum levels (R = 0.9, p = .001). Insulin-like growth factor binding protein (IGFBP)-2 was significantly higher and IGFBP-3 was significantly lower in critically ill children (p = .03 and p = .04 vs. recovery phase, respectively). No other hormonal differences were found. Serum albumin was significantly lower in sick children. We found a significant correlation between prealbumin and RBP and IGFBP-3 (R = 0.6, p = 0.03 and R = 0.6, p = .04, respectively). Alpha-ketoisocaproic turnover positively correlated with IGFBP-1 (R = 0.79, p = .01) and did not correlate with insulin-like growth factor I (R = -0.5, p = .15 [not significant]) No other correlations were found. Lipid turnover measurements did not correlate with any endogenous hormone levels or with duration of critical illness.
  
  
  CONCLUSIONS
  Protein turnover but not lipolysis correlated with a persisting critically ill condition, serum prealbumin, RBP, and plasma IGFBP-1.
authors.affiliation: Department of Pediatrics, Azienda Ospedaliera of Padova, Italy. paolac@child.pedi.unipd.it
authors.forename: Paola E
authors.initials: PE
authors.lastname: Cogo
authors.forename: Virgilio P
authors.initials: VP
authors.lastname: Carnielli
authors.forename: Federica
authors.initials: F
authors.lastname: Rosso
authors.forename: Arianna
authors.initials: A
authors.lastname: Cesarone
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Giordano
authors.forename: Diego
authors.initials: D
authors.lastname: Faggian
authors.forename: Mario
authors.initials: M
authors.lastname: Plebani
authors.forename: Antonina
authors.initials: A
authors.lastname: Barreca
authors.forename: Franco
authors.initials: F
authors.lastname: Zacchello
mesh_terms: D002096:C-Peptide / Q000378:metabolism; D002250:Carbon Radioisotopes; D002675:Child, Preschool; D016638:Critical Illness; D005990:Glycerol / Q000378:metabolism; D013006:Growth Hormone / Q000378:metabolism*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D018969:Insulin-Like Growth Factor Binding Proteins / Q000378:metabolism; D007651:Keto Acids / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D008066:Lipolysis / Q000502:physiology*; D019308:Palmitic Acid / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D012177:Retinol-Binding Proteins / Q000378:metabolism; D054839:Retinol-Binding Proteins, Plasma; D013972:Thyrotropin / Q000378:metabolism; D013974:Thyroxine / Q000378:metabolism; D014284:Triiodothyronine / Q000378:metabolism
chemical_list: D002096:C-Peptide; D002250:Carbon Radioisotopes; D007328:Insulin; D018969:Insulin-Like Growth Factor Binding Proteins; D007651:Keto Acids; D011506:Proteins; D012177:Retinol-Binding Proteins; D054839:Retinol-Binding Proteins, Plasma; D014284:Triiodothyronine; D019308:Palmitic Acid; C013082:alpha-ketoisocaproic acid; D013972:Thyrotropin; D013006:Growth Hormone; D007930:Leucine; D005990:Glycerol; D013974:Thyroxine