title: Myofibrillar protein overdegradation in overweight patients with chronic heart failure: the relationship to serum potassium levels.
abstract: OBJECTIVE
  Muscle release of the amino acid 3-methyl-histidine (3MH) is a sensitive index of myofibrillar protein overdegradation (MPO). We hypothesized that patients with chronic heart failure (CHF) could have increased muscle release of 3MH, which in turn reflects MPO, and that serum electrolyte sodium (Na(+)) and potassium (K(+)) levels may be associated with this 3MH muscle release.
  
  
  METHODS
  Thirty-one overweight outpatients (body mass index, 27 ± 4.4 kg/m(2); 22 men and 9 women; age, 56 ± 8.7 y) with clinically stable CHF were studied. After a 24-hour meat-free diet and overnight fasting, patients underwent blood sampling from a cannulated arm vein (V) and concomitantly from the arterial artery (A) to determine plasma 3MH levels and to calculate the A-V difference. Serum levels of Na(+) and K(+) in the venous blood were determined, and the Na(+)/K(+) ratio was calculated. Ten healthy subjects who were matched for gender, age, and body mass index served as controls and underwent the same protocol as the patients with CHF.
  
  
  RESULTS
  The patient group had higher arterial (P = 0.02) and venous (P = 0.005) 3MH levels but a similar A-V 3MH difference (P = 0.28) as compared with the controls. Within the CHF group, 67.7% of patients released 3MH, which resulted in a negative A-V value (P < 0.02 as compared with controls). In patients with CHF, the A-V 3MH difference correlated positively with the serum K(+) level (r = 0.62; P = 0.0002) and negatively with Na(+)/K(+) ratio (r = -0.55; P = 0.002). No association was found between the A-V 3MH difference and the Na(+) level.
  
  
  CONCLUSIONS
  The study demonstrated the existence of MPO in resting overweight patients with CHF, thereby suggesting that low serum levels of K(+) may contribute to MPO.
authors: Servizio di Fisiopatologia Metabolico-Nutrizionale e Nutrizione Clinica, Fondazione S. Maugeri, IRCCS, Istituto Scientifico di Montescano, Montescano (PV), Italy.
authors: Roberto
authors: R
authors: Aquilani
authors: Divisione di Cardiologia, Fondazione S. Maugeri, IRCCS, Istituto Scientifico di Montescano, Montescano (PV), Italy.
authors: Maria Teresa
authors: MT
authors: La Rovere
authors: Direzione Scientifica Centrale, Fondazione S. Maugeri, IRCCS, Pavia, Italy.
authors: Paola
authors: P
authors: Baiardi
authors: Divisione di Cardiologia, Fondazione S. Maugeri, IRCCS, Istituto Scientifico di Montescano, Montescano (PV), Italy.
authors: Oreste
authors: O
authors: Febo
authors: Dipartimento di Scienze del Farmaco, Università degli Studi di Pavia, Pavia, Italy.
authors: Federica
authors: F
authors: Boschi
authors: Dipartimento di Scienze del Farmaco, Università degli Studi di Pavia, Pavia, Italy.
authors: Anna Maria
authors: AM
authors: Condino
authors: Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", Università degli Studi di Pavia, Pavia, Italy. Electronic address: labmio@unipv.it.
authors: Ornella
authors: O
authors: Pastoris
authors: Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", Università degli Studi di Pavia, Pavia, Italy.
authors: Paolo
authors: P
authors: Iadarola
authors: Dipartimento di Medicina Molecolare, Università degli Studi di Pavia, Pavia, Italy.
authors: Simona
authors: S
authors: Viglio
authors: Istituto Scientifico di Lumezzane (Brescia) Fondazione "Salvatore Maugeri", IRCCS, Italy.
authors: Evasio
authors: E
authors: Pasini
authors: Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", Università degli Studi di Pavia, Pavia, Italy.
authors: Andria Innocenza
authors: AI
authors: Bongiorno
authors: Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", Università degli Studi di Pavia, Pavia, Italy.
authors: Maurizia
authors: M
authors: Dossena
authors: Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", Università degli Studi di Pavia, Pavia, Italy.
authors: Manuela
authors: M
authors: Verri
mesh_terms: D001158:Arteries / Q000378:metabolism; D016022:Case-Control Studies; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000150:complications* / Q000378:metabolism; D006801:Humans; D008297:Male; D008762:Methylhistidines / Q000378:metabolism*; D008875:Middle Aged; D009124:Muscle Proteins / Q000378:metabolism*; D009210:Myofibrils / Q000378:metabolism*; D009765:Obesity / Q000097:blood / Q000150:complications / Q000378:metabolism*; D011188:Potassium / Q000097:blood*; D012964:Sodium / Q000097:blood; D014680:Veins / Q000378:metabolism
chemical_list: D008762:Methylhistidines; D009124:Muscle Proteins; D012964:Sodium; C028118:3-methylhistidine; D011188:Potassium
keywords: Muscle overdegradation; Overweight chronic heart failure; Plasma 3-methyl-hystidine; Sarcopenia; Serum potassium