Associations Between Muscle-Related Cytokines and Selected Patient Outcomes in the ICU

Abstract

Introduction Systemic cytokines produced by contracting skeletal muscles may affect the onset and severity of intensive care unit (ICU)-acquired weakness after critical illness. Aims The purpose of this research was to determine the serum levels of interleukin (IL)-8, IL-15, and tumor necrosis factor-α (TNF-α) among patients receiving mechanical ventilation for >48 hr and examine the relationships of these myokines to outcomes of patient delirium, muscle strength, activities of daily living (ADLs), duration of mechanical ventilation, and length of ICU stay. Methods In this exploratory, repeated-measures interventional study, the 36 participants received 20 min of once-daily in-bed or out-of-bed activity using an established early progressive mobility protocol after physiologic stability had been demonstrated for ≥4 hr in the ICU. Blood samples were drawn on 3 consecutive days, beginning on the day of study enrollment, for serum cytokine quantification. Results IL-8, IL-15, and TNF-α were highly variable and consistently elevated in participants compared to normal healthy adults. About 1/3 of participants were positive for significant muscle weakness at discharge from ICU. Repeated values of mean postactivity IL-8 serum values were significantly associated only with ADL following ICU discharge. There were no significant associations with repeated values of mean postactivity IL-15 or TNF-α serum values and outcomes. Conclusion Results provide preliminary data for exploring the potential effects of elevated serum values IL-8 and IL-15 in muscle health and TNF-α for muscle damage, including effect sizes to calculate the sample sizes needed for future studies.

Clinical efficacy of blood purification using a polymethylmethacrylate hemofilter for the treatment of severe acute pancreatitis

“…A previous study has reported that systemic inflammation was associated with ICU-acquired weakness and indicated that IL-6, TNF-α, or other cytokines could play roles in this pathogenesis [26]. In our study, one patient with ICU-acquired weakness did not show any improvement during treatment with PMMA-CHD.…”

Out of Control: The Role of the Ubiquitin Proteasome System in Skeletal Muscle during Inflammation

“…Rats treated with recombinant TNF or IL-1β showed a significant reduction in total muscle protein content and a reduced expression of myofibrillar proteins [ 201 , 202 ]. ICU patients displayed increased TNF serum levels [ 203 ], and maximal TNF plasma levels were found to be higher in patients who developed ICUAW as compared with control subjects [ 204 ]. Importantly, the administration of an anti-TNF antibody inhibited the sepsis-induced increase in muscle proteolysis in rats, indicating that TNF is an important regulator of muscle protein breakdown during sepsis [ 205 ].…”

Dose of Early Therapeutic Mobility: Does Frequency or Intensity Matter?

“…We estimated that a sample size of 50 would have .80 power to detect a .30 effect size with an a of .10, using Analysis of Covariance (ANCOVA) repeated measures both within and between interactions (Faul et al, 2007). The effect size used in this calculation was larger than what we had obtained in an earlier study (Winkelman, Johnson, & Gordon, 2015); we anticipated fewer missed interventions and greater dose from twice-daily completion leading to a greater effect. We selected a larger a value due to the established safety of the intervention (Morris et al, 2008;Winkelman et al, 2012).…”