SAT-155 Temporal Activation of the Unfolded Protein Response and Concomitant Downregulation of Key Hepatic Transcription Factors in Critical Illness

Background: Critically ill patients often develop multiple organ failure accompanied by profound metabolic and endocrine alterations. The pathogenesis is incompletely understood, but the development of cellular stress, including endoplasmic reticulum (ER) stress, might play a pivotal role (1). Indeed, markers of ER stress have been observed in critical illness, both in animal models and human patients, correlating with organ dysfunction (1). ER stress normally activates the unfolded protein response (UPR). The UPR follows a distinct temporal pattern, aimed at restoring ER homeostasis in the short term, but inducing apoptosis whenever ER stress becomes too severe or prolonged. During critical illness, the temporal activation pattern in liver has only been partially studied. In addition, the potential implications for liver function and metabolism are currently unknown. Methods: We quantified the hepatic expression of crucial markers of the 3 UPR branches and of key hepatic transcription factors in a clinically relevant fluid-resuscitated mouse model of sepsis. Mice were sacrificed at 10 hrs, 30 hrs or 3 days after cecal ligation and puncture in comparison with healthy pair-fed mice (n=15 per group per time point). We quantified the same markers in postmortem liver biopsies from patients admitted to the intensive care unit with sepsis (n=64), who died after a median ICU stay of 10 days (IQR 6-20 days), in comparison with matched patients undergoing elective restorative rectal surgery (n=18). Results: In septic mice, the UPR showed a distinct temporal pattern. In the acute phase (10-30 hrs), the PERK, IRE1α and ATF6 branches were all activated (p˂0.01). In the prolonged phase (3 days), the PERK and ATF6 branches were attenuated and only the IRE1α branch remained activated (p˂0.0001). The UPR activation in the acute phase coincided with a significant downregulation of key hepatic transcription factors important for normal liver function and metabolism, including Shp, FXR, Lrh1, PXR, Hnf6 and Foxa2 (p˂0.01). Several transcription factors remained significantly downregulated in the prolonged phase. ALT as liver damage marker correlated directly with several UPR markers and inversely with several transcription factors in the acute phase, but not in the prolonged phase. In postmortem liver biopsies of patients with sepsis, we only observed an upregulation of the IRE1α branch of the UPR, consistent with the pattern in prolonged critically ill mice. Also in patients, this coincided with a repression of several key hepatic transcription factors. Conclusion: The present findings suggest that patients admitted to the intensive care unit with sepsis develop a state of chronic ER stress in the liver, which might hamper normal hepatic function at least in part through the downregulation of key transcription factors. References: 1. Thiessen SE et al. BBA-Mol Basis Dis 2017, 1863, 2534-45

Obstetric Admissions to the Intensive Care Unit in a Tertiary Hospital

AIMS

A better understanding of the characteristics of obstetric patients admitted to an intensive care unit (ICU) could guide where the focus of obstetric training and awareness should be directed at to reduce further maternal mortality and morbidity.

METHODS

We retrospectively assessed the charts of all women admitted during pregnancy or postpartum to a tertiary ICU over a 12-year period. We retrieved whether women were followed locally or referred from another hospital and whether the ICU admission was prophylactic or therapeutic.

RESULTS

There were 190 admissions in 183 women. One-hundred and four admissions were in referred women and 86 in women cared for locally. Seventy-eight admissions (41.1%) were for direct obstetric causes (primarily postpartum hemorrhage (n = 14), hypertensive disorders of pregnancy (n = 12) and peripartum cardiomyopathy (n = 10)). Indirect obstetric admissions (n = 89; 46.8%) were primarily for cardiopathies (n = 35) and pulmonary diseases (n = 18). Among non-obstetric admissions, trauma (n = 6; 26.1%) and neurologic tumors (n = 6; 26.1%) were the most common.

CONCLUSION

Pre-existing and acquired cardiopathies are the main reason for admission to an ICU in a developed country and have surpassed hypertensive disorders and hemorrhage. This should become a focus of obstetric care provider training.

Interobserver agreement of Medical Research Council sum-score and handgrip strength in the intensive care unit

INTRODUCTION

Muscle weakness often complicates critical illness and is associated with devastating short- and long-term consequences. For interventional studies, reliable measurements of muscle force in the intensive care unit (ICU) are needed.

METHODS

To examine interobserver agreement, two observers independently measured Medical Research Council (MRC) sum-score (n = 75) and handgrip strength (n = 46) in a cross-sectional ICU sample.

RESULTS

The intraclass correlation coefficient (ICC) for MRC sum-score was 0.95 (0.92-0.97). The kappa coefficient for identifying "significant weakness" (MRC sum-score <48, MRC subtotal upper limbs <24) and "severe weakness" (MRC sum-score <36) was 0.68 ± 0.09, 0.88 ± 0.07, and 0.93 ± 0.07, respectively. The ICC for left and right handgrip strength was 0.97 (0.94-0.98) and 0.93 (0.86-0.97), respectively.

CONCLUSIONS

Interobserver agreement on MRC sum-score and handgrip strength in the ICU was very good. Agreement on "severe weakness" (MRC sum-score <36) was excellent and supports its use in interventional studies. Agreement on "significant weakness" (MRC sum-score <48) was good, but even better using the equivalent cut-off in the upper limbs. It remains to be determined whether this may serve as a substitute.

Dynamic data analysis and data mining for prediction of clinical stability

This work studies the impact of using dynamic information as features in a machine learning algorithm for the prediction task of classifying critically ill patients in two classes according to the time they need to reach a stable state after coronary bypass surgery: less or more than nine hours. On the basis of five physiological variables different dynamic features were extracted. These sets of features served subsequently as inputs for a Gaussian process and the prediction results were compared with the case where only admission data was used for the classification. The dynamic features, especially the cepstral coefficients (aROC: 0.749, Brier score: 0.206), resulted in higher performances when compared to static admission data (aROC: 0.547, Brier score: 0.247). In all cases, the Gaussian process classifier outperformed logistic regression.

Incidence and risk factors for pressure ulcers in the intensive care unit

AIMS

To determine the incidence of pressure ulcers occurring at least 48 hours after admission and risk factors for pressure ulcers grade 2-4 in a long-stay surgical Intensive Care Unit (ICU) population.

BACKGROUND

The incidence of pressure ulcers in intensive care units is larger than in non-intensive environments.

DESIGN

Prospective descriptive research design.

METHODS

Using pressure ulcers grade 2-4 as an outcome measure, a multivariate logistic regression analysis was used to identify the risk factors. Data were obtained on a daily basis in a surgical intensive care unit of the University Hospital Leuven between November 2003-March 2004. A total of 520 long-stay (>or= 24 hours) intensive care patients were included.

RESULTS

Cumulative incidence of pressure ulcers grade 2-4 was 20.1%. The following variables were positively associated with pressure ulcers grade 2-4: history of vascular disease, treatment with Dopamine or Dobutamine, intermittent haemodialysis (IHD) or continuous veno-venous haemofiltration (CVVH), mechanical ventilation. Also preventive measures were statistically positively associated with pressure ulcers grade 2-4: turning, floating heels, alternating mattresses, adequate prevention. The use of sedatives, body temperature above 38.5 degrees C and sitting in chair where negatively associated with pressure ulcers. Pressure ulcers are statistically associated with different risk factors and preventive measures.

CONCLUSION

The identified risk factors are eligible to be included in a new risk assessment scale for patients admitted to intensive care units.

RELEVANCE TO CLINICAL PRACTICE

The novel insights have implications for risk assessment for patients in intensive care units. Patients admitted to intensive care units have other risk factors for pressure ulcers which are eligible to be included in a new risk assessment scale.

Thyroid hormone receptor isoform expression in livers of critically ill patients

OBJECTIVE

The THRA gene encodes two isoforms of the thyroid hormone receptor (TR), TRalpha1 and TRalpha2. The ratio of these splice variants could have a marked influence on T3-regulated gene expression, especially during illness.

DESIGN

We studied the expression of the isoforms TRbeta1, TRalpha1, and TRalpha2 and 5'-deiodinase in postmortem liver biopsies of 58 patients who were critically ill and died in the intensive care unit (ICU). All mRNA levels were determined using real-time PCR.

MAIN OUTCOME

All ratios of the biopsies were higher than those found in three normal liver biopsies due to an increased TRalpha1 level. The TRalpha1/TRalpha2 ratio increased with age and severity of illness following the equation: TRalpha1/TRalpha2 ratio = - 1.854 + (0.0323 x age) + (0.0431 x Therapeutic Intervention Scoring System score) indicating that 28% of the changed TRalpha1/TRalpha2 ratio can be predicted by these clinical variables. There was no effect of randomization to intensive insulin therapy or glucocorticoid or thyroid hormone treatment on the TRalpha1/TRalpha2 ratio or TRbeta1. Furthermore, no relation was seen between the expression levels of the 5'-deiodinase mRNA and TR isoforms or the triiodothyronine T3 levels.

CONCLUSION

It appears that in critically ill patients the ratio of TRalpha1/TRalpha2 expression increases with age and severity of illness, possibly indicating a mechanism to enhance sensitivity to T3 in the oldest and sickest patients.

Regulation of insulin-like growth factor binding protein-1 during protracted critical illness

IGF binding protein-1 (IGFBP-1), an important regulator of IGF bioavailability, has been shown to correlate with mortality in critically ill patients. In the liver, IGFBP-1 is transcriptionally repressed by insulin, and it is therefore a potential marker of hepatic insulin sensitivity. We have recently shown that, compared with conventional treatment, maintenance of normoglycemia with intensive insulin therapy decreased morbidity and mortality of continuously fed critically ill patients. This study compares the effect of conventional and intensive insulin therapy on IGFBP-1 and assesses its predictive value for mortality. In 363 patients who were dependent on intensive care for more than 7 d and were randomly assigned to either conventional or intensive insulin therapy, serum IGFBP-1 levels were measured on admission, on d 1, 8, 15, 22, and 29, and on the day of intensive care unit discharge or death. In addition, IGFBP-1 and phosphoenolpyruvate carboxykinase mRNA levels were measured by real-time RT-PCR in postmortem liver biopsies obtained from 74 patients who died in the intensive care unit. Although intensive insulin treatment lowered glycemia, it had no effect on IGFBP-1 serum levels. Instead, serum IGFBP-1 concentration was significantly higher in patients who ultimately died, and it differentiated nonsurvivors from survivors 3 wk before death. The predictive value of serum IGFBP-1 for mortality was similar to that of the APACHE-II score. Like circulating IGFBP-1, hepatic mRNA levels of IGFBP-1 and the similarly insulin-regulated gene, phosphoenolpyruvate carboxykinase, were not significantly different between conventional and intensive insulin therapy groups. These data suggest that hepatic insulin resistance in prolonged critically ill patients, reflected by high serum IGFBP-1 levels, is not overcome by intensive insulin therapy, and that this may affect patient outcome.