Neuromuscular Recovery Is Prolonged After Immobilization or Superimposition of Inflammation With Immobilization Compared to Inflammation Alone: Data From a Preclinical Model

Association between changes in disease severity and physical function after surviving a critical illness: A multicentre retrospective observational study

BACKGROUND

Whilst disease severity can significantly impact functional outcomes, the ability to predict the scale of this impact has not been consistent.

AIM

We aimed to investigate whether changes in disease severity within the first 48 h of ICU admission are more strongly associated with physical dysfunction than a single-time assessment of disease severity at ICU admission.

METHODS

A multicentre retrospective study in seven tertiary ICUs in Japan, including all consecutive adult ICU patients (>48 h ICU stay) between September 2019 and February 2020. The primary outcome was physical function defined as the Barthel Index, which is an ordinal scale (0-100: larger indicates better function) to measure physical independence and performance. The association between Barthel Index score at hospital discharge and the Sequential Organ Failure Assessment (SOFA) scores, measured at ICU admission, the highest recorded score within 48 h of ICU admission, and the level of change between these two timepoints were investigated in multivariable analysis.

RESULTS

A total of 199 patients were included. Median SOFA score at ICU admission and the highest recorded score within the first 48 h were 6 (interquartile range: 5-10) and 8 (interquartile range: 6-11), respectively. A quarter of patients had a Barthel Index score of 60 or less at hospital discharge. The highest SOFA score within 48 h of ICU admission and the level of change in SOFA scores between ICU admission and the highest recorded score within 48 h were significantly associated with lower Barthel Index scores at hospital discharge. No significant association was identified with regard to Barthel Index scores and SOFA score at ICU admission. An increase in SOFA score of 1 or more within the first 48 h of ICU admission was the threshold to predict a Barthel Index score of 60 or less at hospital discharge. Larger changes in SOFA scores over the first 48 h of ICU admission were also significantly associated with smaller changes in Barthel Index scores from ICU discharge to hospital discharge.

CONCLUSIONS

The level of change in SOFA score between ICU admission and the highest recorded score within the first 48 h of ICU stay can more accurately predict the presence of physical dysfunction at hospital discharge than a single-time assessment of disease severity at ICU admission. The larger worsening in SOFA potentially indicates lower recovery after a critical illness.

Recombinant human neuregulin-1 alleviates immobilization-induced neuromuscular dysfunction via neuregulin-1/ErbB signaling pathway in rat

Immobilization-induced Neuromuscular Dysfunction (NMD) increases morbidity and mortality of patients in Intensive Care Units. However, the underlying mechanism of NMD remain poorly elucidated which limited the development of therapeutic method for NMD. Here we developed an immobilization rat model and tested the hypothesis that decreased expression of NRG-1, abnormal expression and distribution of nicotinic acetylcholine receptors (nAChRs) in skeletal muscle caused by immobilization can lead to NMD. To investigate the role of NRG-1/ErbB pathway on immobilization-induced NMD, exogenous recombinant human neuregulin-1 (rhNRG-1) was used to increase the expression of NRG-1 in skeletal muscle during immobilization. It was observed rhNRG-1 significantly alleviated the muscle loss and enhanced the expression of ε-nAChR, while diminished the expression of γ- and α7-nAChR and NMD. Interestingly, ErbB inhibitor PD158780 blocked the protective effects of rhNRG-1. Collectively, the results of present study suggested that rhNRG-1 attenuated immobilization-induced muscle loss and NMD, suppressed γ- and α7-nAChR production, enhanced ε-nAChR synthesis via activating NRG-1/ErbB pathway. Taken together, our findings provide novel insights into NMD contribution, suggesting that the rhNRG-1 is a promising therapy to protect against immobilization-induced myopathy.

Optimal timing of introducing mobilization therapy for ICU patients with sepsis

Background

For patients admitted to the intensive care unit (ICU) with sepsis, mobilization therapy during ICU stay can improve their outcomes during and after the ICU stay. However, little is known about the optimal timing of introducing mobilization therapy.

Methods

This is a retrospective cohort study using data from a tertiary medical center in Japan during 2013–2017. We included patients aged ≥ 18 years who were admitted to the ICU with sepsis based on the Sepsis-3 criteria. We defined early mobilization (EM) as the rehabilitation at the level of sitting on the edge of the bed or more within the first 3 days of the patients’ ICU stay. Patients were divided into the EM and non-EM groups. The primary outcomes were in-hospital mortality and ambulatory dependence at hospital discharge. We estimated the effects of EM by stabilized inverse probability weighting (sIPW). We then tested alternative definitions of EM by changing the cutoff in days to mobilization by 1-day increments from 2 to 7 days to investigate the optimal timing of mobilization.

Results

Our study sample consisted of a total of 296 septic patients, including 96 patients in the EM group and 200 patients in the non-EM group. In the sIPW model, the adjusted OR for in-hospital mortality in the EM group compared to the non-EM group was 0.22 [95% CI 0.06–0.88], and the adjusted OR for ambulatory dependence at the hospital discharge was 0.24 [95% CI 0.09–0.61]. When alternative definitions of EM were tested, patients who achieved mobilization within the first 2–4 days of their ICU stays had better outcomes.

Conclusions

Achieving mobilization within the first 3 days of ICU stay was significantly associated with better outcomes. Patients with sepsis might benefit most from achieving mobilization within 2–4 days. Further studies are warranted to validate the findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-022-00613-8.

The Role of Dietary Fats in the Development and Prevention of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a significant cause of mortality and morbidity in preterm infants. The pathogenesis of NEC is not completely understood; however, intestinal immaturity and excessive immunoreactivity of intestinal mucosa to intraluminal microbes and nutrients appear to have critical roles. Dietary fats are not only the main source of energy for preterm infants, but also exert potent effects on intestinal development, intestinal microbial colonization, immune function, and inflammatory response. Preterm infants have a relatively low capacity to digest and absorb triglyceride fat. Fat may thereby accumulate in the ileum and contribute to the development of NEC by inducing oxidative stress and inflammation. Some fat components, such as long-chain polyunsaturated fatty acids (LC-PUFAs), also exert immunomodulatory roles during the early postnatal period when the immune system is rapidly developing. LC-PUFAs may have the ability to modulate the inflammatory process of NEC, particularly when the balance between n3 and n6 LC-PUFAs derivatives is maintained. Supplementation with n3 LC-PUFAs alone may have limited effect on NEC prevention. In this review, we describe how various fatty acids play different roles in the pathogenesis of NEC in preterm infants.

GTS-21 attenuates loss of body mass, muscle mass, and function in rats having systemic inflammation with and without disuse atrophy

Muscle changes of critical illness are attributed to systemic inflammatory responses and disuse atrophy. GTS-21 (3-(2,4-dimethoxy-benzylidene)anabaseine), also known as DMBX-A) is a synthetic derivative of the natural product anabaseine that acts as an agonist at α7-acetylcholine receptors (α7nAChRs). Hypothesis tested was that modulation of inflammation by agonist GTS-21 (10 mg/kg b.i.d. intraperitoneally) will attenuate body weight (BW) and muscle changes. Systemic sham inflammation was produced in 125 rats by Cornyebacterium parvum (C.p.) or saline injection on days 0/4/8. Seventy-four rats had one immobilized-limb producing disuse atrophy. GTS-21 effects on BW, tibialis muscle mass (TMM), and function were assessed on day 12. Systemically, methemoglobin levels increased 26-fold with C.p. (p < 0.001) and decreased significantly (p < 0.033) with GTS-21. Control BW increased (+ 30 ± 9 g, mean ± SD) at day 12, but decreased with C.p. and superimposed disuse (p = 0.005). GTS-21 attenuated BW loss in C.p. (p = 0.005). Compared to controls, TMM decreased with C.p. (0.43 ± 0.06 g to 0.26 ± 0.03 g) and with superimposed disuse (0.18 ± 0.04 g); GTS-21 ameliorated TMM loss to 0.32 ± 0.04 (no disuse, p = 0.028) and to 0.22 ± 0.03 (with disuse, p = 0.004). Tetanic tensions decreased with C.p. or disuse and GTS-21 attenuated tension decrease in animals with disuse (p = 0.006) and in animals with C.p. and disuse (p = 0.029). C.p.-induced 11-fold increased muscle α7nAChR expression was decreased by > 60% with GTS-21 treatment. In conclusion, GTS-21 modulates systemic inflammation, evidenced by both decreased methemoglobin levels and decrease of α7nAChR expression, and mitigates inflammation-mediated loss of BW, TMM, fiber size, and function.