Diaphragm Atrophy and Weakness in the Absence of Mitochondrial Dysfunction in the Critically Ill

Marloes van den Berg, Pleuni E Hooijman, Albertus Beishuizen, Monique C de Waard, Marinus A Paul, Koen J Hartemink, Hieronymus W H van Hees, Michael W Lawlor, Lorenza Brocca, Roberto Bottinelli, Maria A Pellegrino, Ger J M Stienen, Leo M A Heunks, Rob C I Wüst, Coen Ac Ottenheijm

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

RATIONALE: The clinical significance of diaphragm weakness in critically ill patients is evident: it prolongs ventilator dependency, and increases morbidity, duration of hospital stay and health care costs. The mechanisms underlying diaphragm weakness are unknown, but might include mitochondrial dysfunction and oxidative stress.

OBJECTIVES: We hypothesized that weakness of diaphragm muscle fibers in critically ill patients is accompanied by impaired mitochondrial function, structure, and increased markers of oxidative stress.

METHODS: To test these hypotheses, we studied contractile force, mitochondrial function, and mitochondrial structure in diaphragm muscle fibers. Fibers were isolated from diaphragm biopsies of thirty-six mechanically ventilated critically ill patients and compared to those isolated from biopsies of twenty-seven patients with suspected early-stage lung malignancy (controls).

MEASUREMENTS AND MAIN RESULTS: Diaphragm muscle fibers from critically ill patients displayed significant atrophy and contractile weakness, but lacked impaired mitochondrial respiration and increased levels of oxidative stress markers. Mitochondrial energy status and morphology were not altered, despite a lower content of fusion proteins.

CONCLUSIONS: Critically ill patients have manifest diaphragm muscle fiber atrophy and weakness, in the absence of mitochondrial dysfunction and oxidative stress. Thus, mitochondrial dysfunction and oxidative stress do not play a causative role in the development of atrophy and contractile weakness of the diaphragm in critically ill patients.

Original languageEnglish
Pages (from-to)1544-1558
Number of pages15
JournalAmerican Journal of Respiratory and Critical Care Medicine
Volume196
Issue number12
DOIs
Publication statusPublished - 15 Dec 2017

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