Czy HSP-27 jest nowym markerem dobrego rokowania u pacjentów ze wstrząsem septycznym? Badanie pilotażowe

Introduction

Sepsis is a life-threatening organ dysfunction caused by an abnormal host response to infection, while septic shock (SS) is a subgroup of sepsis in which abnormalities in circulatory and cellular metabolism are profound enough to significantly increase mortality. Sepsis and septic shock (SS) are among the main causes of death in critically ill patients. Many biomarkers are used to assess the severity of sepsis and SS, but none are highly sensitive in predicting outcome [1, 2]. Moreover, most studies refer to baseline levels of estimated markers rather than changes in marker levels.

Aim of the research

The aim of the study was to estimate the usefulness of changes in some biochemical markers in prognosis of SS.

Material and methods

This prospective observational study was conducted in accordance with the Declaration of Helsinki and the study protocol, which was approved by the Institutional Review Board and the Bioethics Committee of the Medical University at Lublin, Poland (KE-0254/306/2018). Written informed consent was obtained from all conscious patients or, in case of sedation and mechanical ventilated, from the patients’ legal representative.
Included in the study were adult patients with SS. The exclusion criteria were as follows: age < 18 years, more than 24 h after the onset of symptoms of SS, pregnancy, comorbidities and drugs affecting the immune system, kidney injury requiring dialysis, death during < 48 h after admission. All patients were treated in accordance with the guidelines of the Surviving Sepsis Campaign [1, 2].
Serum levels of biomarkers were measured at admission and daily for 4 consecutive days (time points T0,T1, T2, T3 and T4 respectively). The mortality rate was determined 28 days after admission. Patients were divided into survivor and non-survivor groups according to their mortality. The differences between the levels of biomarkers at the time points T0 and T4 were analyzed. Serum levels of C-reactive protein (CRP), procalcitonin, presepsin, heat shock protein 27 (HSP27) and neutrophil to lymphocyte ratio (NLR) were assessed and analyzed.

Statistical analysis

The statistical significance of the differences between groups was compared using Student’s t-test or using the Mann-Whitney U-test, when appropriate. Cumulative survival curves were constructed using the Kaplan-Meier method for 28-day mortality. Differences between patient groups were assessed using the log-rank test. Independent risk factors affecting prognosis were analyzed by univariate and multivariate logistic regression analysis. Explanatory variables with a p-value ≤ 0.15 in the univariate analysis were entered into a multivariate analysis. The ROC curve was used to evaluate the diagnostic sensitivity, specificity, and optimal cut-off value. Probability values of p < 0.05 were accepted as significant.

Results

Out of 48 patients initially included in the study, 11 were excluded due to the need of operation (6), death during < 48 h after admission (3), or incomplete data (2). The remaining 37 patients (24 females and 23 males), aged 57–74 years (mean: 66.1 ±7.13) entered the study. Twenty-one patients were treated for SS complicating pneumonia, 10 for SS complicating the postoperative period after gastrointestinal surgery, and 4 for SS complicating urinary tract infection. The mean value of the SOFA score on admission was 11.7 ±2.7, and the APACHE II scale 29.9 ±6.85. All patients required both ventilation and inotropic agents’ treatment. Nine (24.3%) patients died during the follow-up.
Changes in estimated biochemical parameters on successive days are presented in Table 1. A decrease of procalcitonin and CRP was observed at T4 compared to T0 in both survivors and non-survivors, but the decrease was more pronounced in survivors. For both presepsin and NLR, a decrease was observed only in survivors, while the decrease of NLR was only marginal. In the case of HSP27 an increase at T4 was observed exclusively in survivors, whereas in non-survivors no changes in HSP27 levels were found. An increase of HSP27 first occurred at T3 and a further sharp increase was observed between T3 and T4. Both uni- and multivariate analysis of serum levels changes between T0 and T4 for 28-day mortality are depicted in Table 2. Univariate logistic analysis revealed that changes between T0 and T4 of presepsin, procalcitonin, and HSP27 were associated with prognosis. A multivariate Cox analysis showed that exclusively an increase in HSP27 in T4 was an independent and strong predictor of a good prognosis in SS patients. The increase at T4 of 8.92 ng/ml was found to be the optimal cut-off value of a good prognosis. The area under the receiver operating characteristics curve for HSP27 was 0.785 (Figure 1). Kaplan-Meier analysis showed that the mortality was lower (p = 0.014) in patients who had an increase in HSP27 at T4 compared to those whose serum HSP27 did not increase at T4 (Figure 2).

Discussion

The main finding of the current study is that an increase in HSP27 level on day 4 was a strong and independent predictor of good prognosis in patients with SS. To our knowledge, this is the first study that has demonstrated the prognostic utility of a HSP27 increase for predicting prognosis in patients with SS. HSP27 is associated with cytoprotective functions under conditions of cellular stress and plays an important role in the host response to various pathophysiological stresses, such as injury, both oxidative and thermal stress, hypoxia, inflammation, and infections, including sepsis. It also plays a role in immune cell activation [3–8]. Data on the role HSP27 plays in sepsis and SS are limited. Recently, it has been demonstrated that in a model of polymicrobial sepsis HSP27 level increase protected mice from sepsis [3]. Moreover, decreased levels of HSP27 were observed in early-onset neonatal sepsis [9]. Enhanced expression of HSPs, including HSP27, was found in activated polymorphonuclear leukocytes in patients with sepsis [10]. There is evidence that in animal models of endotoxin or septic shock the infusion of glutamine induces an increase of HSP27, attenuates organ injury and improves survival of patients [11–13]. These results suggest a potentially protective role of HSP27 against sepsis. Based on our study, we can conclude, however, that an increase in HSP27 is a marker of good prognosis in SS, while determining the potential causal relationship requires further research. If our results are confirmed in future studies, HSP27 may become a marker of prognosis which can be useful in clinical practice. In the future, HSP27 potentially may also become a therapeutic target. The present study has some important limitations. The first limitation is the small number of patients; however, it is sufficient to show a predictive value for HSP27 levels. The second one is that our study is mostly descriptive, and a pathophysiologic explanation for the results needs to be part of further investigations.

Conclusions

The increase of HSP27 level on the 4^th day predicts a good outcome in SS patients.

Conflict of interest

The authors declare no conflict of interest.

References