1
|
Abstract
When critically ill, a severe weakness of the limbs and respiratory muscles often develops with a prolonged stay in the intensive care unit (ICU), a condition vaguely termed intensive care unit-acquired weakness (ICUAW). Many of these patients have serious nerve and muscle injury. This syndrome is most often seen in surviving critically ill patients with sepsis or extensive inflammatory response which results in increased duration of mechanical ventilation and hospital length of stay. Patients with ICUAW often do not fully recover and the disability will seriously impact on their quality of life. In this chapter we discuss the current knowledge on the pathophysiology and risk factors of ICUAW. Tools to diagnose ICUAW, how to separate ICUAW from other disorders, and which possible treatment strategies can be employed are also described. ICUAW is finally receiving the attention it deserves and the expectation is that it can be better understood and prevented.
Collapse
Affiliation(s)
- J Horn
- Department of Intensive Care, Academic Medical Center, Amsterdam, The Netherlands.
| | - G Hermans
- Department of General Internal Medicine, UZ Leuven, Leuven, Belgium
| |
Collapse
|
2
|
Kollmar R. [Critical illness polyneuropathy and myopathy as neurological complications of sepsis]. DER NERVENARZT 2016; 87:236-45. [PMID: 26842898 DOI: 10.1007/s00115-016-0071-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Intensive care unit acquired weakness (ICUAW) is a frequent and severe complication of intensive care management. Within ICUAW critical illness polyneuropathy (CIP) and myopathy (CIM) can be differentiated. The major symptom of ICUAW is progressive quadriparesis, which makes weaning from the respirator more difficult, can appear early after admission to an ICU and can often be detected several months after discharge from the ICU. The pathophysiology of ICUAW is multifactorial and complex. Potential therapeutic approaches are the early and sufficient therapy of mulitorgan dysfunction, optimal control of glucose levels as well as early and intensive physiotherapy. This review article discusses the data on incidence, pathophysiology, diagnostic approaches and prognosis of ICUAW.
Collapse
Affiliation(s)
- R Kollmar
- Klinik für Neurologie und Neurogeriatrie mit neurologischer Intensivmedizin, Grafenstrasse 9, 64289, Darmstadt, Deutschland.
| |
Collapse
|
3
|
Corpeno Kalamgi R, Salah H, Gastaldello S, Martinez-Redondo V, Ruas JL, Fury W, Bai Y, Gromada J, Sartori R, Guttridge DC, Sandri M, Larsson L. Mechano-signalling pathways in an experimental intensive critical illness myopathy model. J Physiol 2016; 594:4371-88. [PMID: 26990577 DOI: 10.1113/jp271973] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/11/2016] [Indexed: 01/07/2023] Open
Abstract
KEY POINTS Using an experimental rat intensive care unit (ICU) model, not limited by early mortality, we have previously shown that passive mechanical loading attenuates the loss of muscle mass and force-generation capacity associated with the ICU intervention. Mitochondrial dynamics have recently been shown to play a more important role in muscle atrophy than previously recognized. In this study we demonstrate that mitochondrial dynamics, as well as mitophagy, is affected by mechanosensing at the transcriptional level, and muscle changes induced by unloading are counteracted by passive mechanical loading. The recently discovered ubiquitin ligases Fbxo31 and SMART are induced by mechanical silencing, an induction that similarly is prevented by passive mechanical loading. ABSTRACT The complete loss of mechanical stimuli of skeletal muscles, i.e. loss of external strain related to weight bearing and internal strain related to activation of contractile proteins, in mechanically ventilated, deeply sedated and/or pharmacologically paralysed intensive care unit (ICU) patients is an important factor triggering the critical illness myopathy (CIM). Using a unique experimental ICU rat model, mimicking basic ICU conditions, we have recently shown that mechanical silencing is a dominant factor triggering the preferential loss of myosin, muscle atrophy and decreased specific force in fast- and slow-twitch muscles and muscle fibres. The aim of this study is to gain improved understanding of the gene signature and molecular pathways regulating the process of mechanical activation of skeletal muscle that are affected by the ICU condition. We have focused on pathways controlling myofibrillar protein synthesis and degradation, mitochondrial homeostasis and apoptosis. We demonstrate that genes regulating mitochondrial dynamics, as well as mitophagy are induced by mechanical silencing and that these effects are counteracted by passive mechanical loading. In addition, the recently identified ubiquitin ligases Fbxo31 and SMART are induced by mechanical silencing, an induction that is reversed by passive mechanical loading. Thus, mechano-cell signalling events are identified which may play an important role for the improved clinical outcomes reported in response to the early mobilization and physical therapy in immobilized ICU patients.
Collapse
Affiliation(s)
- Rebeca Corpeno Kalamgi
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Heba Salah
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Stefano Gastaldello
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | | | - Jorge L Ruas
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Wen Fury
- Regeneron Pharmaceuticals, Tarrytown, 10591, NY, USA
| | - Yu Bai
- Regeneron Pharmaceuticals, Tarrytown, 10591, NY, USA
| | | | - Roberta Sartori
- Venetian Institute of Molecular Medicine, 35131, Padova, Italy.,Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
| | - Denis C Guttridge
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University Medical Centre, Columbus, 43210, OH, USA
| | - Marco Sandri
- Venetian Institute of Molecular Medicine, 35131, Padova, Italy.,Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
| | - Lars Larsson
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77, Stockholm, Sweden.,Department of Clinical Neuroscience, Clinical Neurophysiology, Karolinska Institutet, SE-171 77, Stockholm, Sweden.,Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA, USA
| |
Collapse
|
4
|
Kalamgi RC, Larsson L. Mechanical Signaling in the Pathophysiology of Critical Illness Myopathy. Front Physiol 2016; 7:23. [PMID: 26869939 PMCID: PMC4740381 DOI: 10.3389/fphys.2016.00023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/18/2016] [Indexed: 12/14/2022] Open
Abstract
The complete loss of mechanical stimuli of skeletal muscles, i.e., the loss of external strain, related to weight bearing, and internal strain, related to the contraction of muscle cells, is uniquely observed in pharmacologically paralyzed or deeply sedated mechanically ventilated intensive care unit (ICU) patients. The preferential loss of myosin and myosin associated proteins in limb and trunk muscles is a significant characteristic of critical illness myopathy (CIM) which separates CIM from other types of acquired muscle weaknesses in ICU patients. Mechanical silencing is an important factor triggering CIM. Microgravity or ground based microgravity models form the basis of research on the effect of muscle unloading-reloading, but the mechanisms and effects may differ from the ICU conditions. In order to understand how mechanical tension regulates muscle mass, it is critical to know how muscles sense mechanical information and convert stimulus to intracellular biochemical actions and changes in gene expression, a process called cellular mechanotransduction. In adult skeletal muscles and muscle fibers, this process may differ, the same stimulus can cause divergent response and the same fiber type may undergo opposite changes in different muscles. Skeletal muscle contains multiple types of mechano-sensors and numerous structures that can be affected differently and hence respond differently in distinct muscles.
Collapse
Affiliation(s)
- Rebeca C Kalamgi
- Basic and Clinical Muscle Biology, Department of Physiology and Pharmacology, Karolinska Institutet Stockholm, Sweden
| | - Lars Larsson
- Basic and Clinical Muscle Biology, Department of Physiology and Pharmacology, Karolinska InstitutetStockholm, Sweden; Department of Clinical Neuroscience, Clinical Neurophysiology, Karolinska InstitutetStockholm, Sweden
| |
Collapse
|
5
|
Ochala J, Gustafson AM, Diez ML, Renaud G, Li M, Aare S, Qaisar R, Banduseela VC, Hedström Y, Tang X, Dworkin B, Ford GC, Nair KS, Perera S, Gautel M, Larsson L. Preferential skeletal muscle myosin loss in response to mechanical silencing in a novel rat intensive care unit model: underlying mechanisms. J Physiol 2011; 589:2007-26. [PMID: 21320889 DOI: 10.1113/jphysiol.2010.202044] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The muscle wasting and impaired muscle function in critically ill intensive care unit (ICU) patients delay recovery from the primary disease, and have debilitating consequences that can persist for years after hospital discharge. It is likely that, in addition to pernicious effects of the primary disease, the basic life support procedures of long-term ICU treatment contribute directly to the progressive impairment of muscle function. This study aims at improving our understanding of the mechanisms underlying muscle wasting in ICU patients by using a unique experimental rat ICU model where animals are mechanically ventilated, sedated and pharmacologically paralysed for duration varying between 6 h and 14 days. Results show that the ICU intervention induces a phenotype resembling the severe muscle wasting and paralysis associated with the acute quadriplegic myopathy (AQM) observed in ICU patients, i.e. a preferential loss of myosin, transcriptional down-regulation of myosin synthesis, muscle atrophy and a dramatic decrease in muscle fibre force generation capacity. Detailed analyses of protein degradation pathways show that the ubiquitin proteasome pathway is highly involved in this process. A sequential change in localisation of muscle-specific RING finger proteins 1/2 (MuRF1/2) observed during the experimental period is suggested to play an instrumental role in both transcriptional regulation and protein degradation. We propose that, for those critically ill patients who develop AQM, complete mechanical silencing, due to pharmacological paralysis or sedation, is a critical factor underlying the preferential loss of the molecular motor protein myosin that leads to impaired muscle function or persisting paralysis.
Collapse
Affiliation(s)
- Julien Ochala
- Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Zink W, Kollmar R, Schwab S. Critical illness polyneuropathy and myopathy in the intensive care unit. Nat Rev Neurol 2010; 5:372-9. [PMID: 19578344 DOI: 10.1038/nrneurol.2009.75] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Critical illness polyneuropathy (CIP) and critical illness myopathy (CIM) are major complications that occur in severely ill patients who require intensive care treatment. CIP and CIM affect the limb and respiratory muscles, and, as a consequence, they characteristically complicate weaning from the ventilator, increase the length of stay on the intensive care unit, and prolong physical rehabilitation. The basic pathophysiology of both disorders is complex and involves metabolic, inflammatory and bioenergetic alterations. It is unclear at present whether CIP and CIM are distinct entities, or whether they just represent different 'organ' manifestations of a common pathophysiological mechanism. This article provides an overview of the clinical and diagnostic features of CIP and CIM and discusses current pathophysiological and therapeutic concepts relating to these neuromuscular disorders.
Collapse
Affiliation(s)
- Wolfgang Zink
- Department of Anesthesiology, University of Regensburg, Germany
| | | | | |
Collapse
|
7
|
Larsson L. Acute quadriplegic myopathy: an acquired "myosinopathy". ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 642:92-8. [PMID: 19181096 DOI: 10.1007/978-0-387-84847-1_8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Acquired neuromuscular disorders have been shown to be very common in critically ill patients receiving prolonged mechanical ventilation in the intensive care unit (ICU). Acute Quadriplegic Myopathy (AQM) is a specific acquired myopathy in ICU patients. Patients with AQM are characterized by severe muscle weakness and atrophy of spinal nerve innervated limb and trunk muscles, while cranial nerve innervated craniofacial muscles, sensory and cognitive functions are spared or less affected. The muscle weakness is associated with altered muscle membrane properties and a preferential loss of the motor protein myosin and myosin-associated thick filament proteins. Prolonged mechanical ventilation, muscle unloading, postsynaptic block of neuromuscular transmission, sepsis and systemic corticosteroid hormone treatment have been suggested as important triggering factors in AQM. However, the exact mechanisms underlying the loss of thick filament proteins are not known, though enhanced myofibrillar protein degradation in combination with a downregulation of protein synthesis at the transcriptional level play important roles.
Collapse
Affiliation(s)
- Lars Larsson
- Department of Clinical Neurophysiology, Uppsala University, Uppsala, Sweden.
| |
Collapse
|
8
|
Abstract
The muscle wasting and loss of muscle function associated with critical illness and intensive care have significant negative consequences for weaning from the respirator, duration of hospital stay, and quality of life for long periods after hospital discharge. There is, accordingly, a significant demand for focused research aiming at improving our understanding of the mechanisms underlying the impaired neuromuscular function in intensive care unit (ICU) patients. However, the study of generalized muscle weakness in critically ill ICU patients is further complicated by the coexistence of multiple independent factors, such as different primary diseases, large variability in pharmacologic treatment, collection of muscle samples several weeks after admission to the ICU, and exposure to causative agents. This has led to the design of specific animal models mimicking ICU conditions. These models have often been used to study the mechanisms underlying the paralysis and muscle wasting associated with acute quadriplegic myopathy in ICU patients. This short review aims at presenting existing and recently introduced experimental animal models mimicking the conditions in the ICU (i.e., models designed to determine the mechanisms underlying the muscle wasting associated with ICU treatment).
Collapse
Affiliation(s)
- Lars Larsson
- Department of Clinical Neurophysiology, Uppsala University Hospital, Uppsala, Sweden.
| |
Collapse
|