Expression of Pancreatic Stone Protein is Unaffected by Trauma and Subsequent Surgery in Burn Patients

Establishment of growth stimulating gene 2 protein time-resolved fluorescence immunoassay and its application in sepsis

AIM

This study aimed to establish a highly sensitive time-resolved fluorescence immunoassay of growth stimulating express gene 2 protein (ST2-TRFIA) and evaluate its application value for sepsis.

METHODS

Two types of ST2 monoclonal specific antibodies against different epitopes of antigen molecule were used as coating and Eu3+-labeled antibodies. The double-antibody sandwich method was used in establishing ST2-TRFIA, and the methodology was evaluated. The established ST2-TRFIA was used in detecting ST2 concentration in the plasma samples of healthy controls and sepsis.

RESULTS

The linear range of ST2-TRFIA was 1.446-500 ng/mL. Plasma ST2 concentrations detected through ST2-TRFIA were consistent with the results of fluorescence quantitative immunochromatography (ρ = 0.946). The plasma ST2 concentrations of patients with sepsis were significantly higher than those of healthy controls (P < 0.01).

CONCLUSION

This study successfully established a highly sensitive ST2-TRFIA, which was highly comparable to commercially available fluorescent quantitative immunochromatographic kits and can facilitate the timely diagnosis of sepsis.

Characterization of a proteomic profile associated with organ dysfunction and mortality of sepsis and septic shock

INTRODUCTION

The search for new biomarkers that allow an early diagnosis in sepsis and predict its evolution has become a necessity in medicine. The objective of this study is to identify, through omics techniques, potential protein biomarkers that are expressed in patients with sepsis and their relationship with organ dysfunction and mortality.

METHODS

Prospective, observational and single-center study that included adult patients (≥ 18 years) who were admitted to a tertiary hospital and who met the criteria for sepsis. A mass spectrometry-based approach was used to analyze the plasma proteins in the enrolled subjects. Subsequently, using recursive feature elimination classification and cross-validation with a vector classifier, an association of these proteins with mortality and organ dysfunction was established. The protein-protein interaction network was analyzed with String software.

RESULTS

141 patients were enrolled in this study. Mass spectrometry identified 177 proteins. Of all of them, and by recursive feature elimination, nine proteins (GPX3, APOB, ORM1, SERPINF1, LYZ, C8A, CD14, APOC3 and C1QC) were associated with organ dysfunction (SOFA > 6) with an accuracy of 0.82 ± 0.06, precision of 0.85 ± 0.093, sensitivity 0.81 ± 0.10, specificity 0.84 ± 0.10 and AUC 0.82 ± 0.06. Twenty-two proteins (CLU, LUM, APOL1, SAA1, CLEBC3B, C8A, ITIH4, KNG1, AGT, C7, SAA2, APOH, HRG, AFM, APOE, APOC1, C1S, SERPINC1, IGFALS, KLKB1, CFB and BTD) were associated with mortality with an accuracy of 0.86 ± 0.05, a precision of 0.91 ± 0.05, a sensitivity of 0.91 ± 0.05, a specificity of 0.72 ± 0.17, and an area under the curve (AUC) of 0.81 ± 0.08 with a confidence interval of 95%.

CONCLUSION

In sepsis there are proteomic patterns associated with organ dysfunction and mortality.

Development and application of a novel aldehyde nanoparticle-based amplified luminescent proximity homogeneous assay for rapid quantitation of pancreatic stone protein

BACKGROUND

Timely diagnosis of bacterial infections is important to prevent sepsis. Classical infection biomarkers have some flaws, and common detection methods are time-consuming. Thus, we aimed to establish an efficient detection method that precisely detects pancreatic stone protein (PSP) in human plasma for the timely diagnosis of bacterial infections.

METHODS

Based on the novel amplified luminescent proximity homogeneous assay (AlphaLISA) method, donor and acceptor beads modified with aldehyde groups were directly coupled to the anti-PSP antibodies. PSP was quickly detected by a double-antibody sandwich method. Plasma samples from healthy individuals, bacterially infected patients, and acute-phase response patients were tested.

RESULTS

The detection time of the developed method is only 5 min. The results of PSP-AlphaLISA and time-resolved fluorescence were consistent (ρ = 0.9722). The plasma PSP levels of patients with bacterial infection were significantly higher than those of acute-phase response patients and healthy individuals (P < 0.05). PSP levels in patients with bacterial infection with sepsis were significantly higher than those in patients with bacterial infection without sepsis (P < 0.05).

CONCLUSIONS

The PSP-AlphaLISA exhibited excellent performance and may be applied to the differential diagnosis between bacterial infection and sepsis in patients without interference from patients with acute-phase response.

Pancreatic Stone Protein: Review of a New Biomarker in Sepsis

Sepsis is a life-threatening syndrome characterized by a dysregulated host response to an infection that may evolve rapidly into septic shock and multiple organ failure. Management of sepsis relies on the early recognition and diagnosis of infection and the providing of adequate and prompt antibiotic therapy and organ support. A novel protein biomarker, the pancreatic stone protein (PSP), has recently been studied as a biomarker of sepsis and the available evidence suggests that it has a higher diagnostic performance for the identification of infection than the most used available biomarkers and adds prognostic value. This review summarizes the clinical evidence available for PSP in the diagnosis and prognosis of sepsis.

Incidence and Time Point of Sepsis Detection as Related to Different Sepsis Definitions in Severely Burned Patients and Their Accompanying Time Course of Pro-Inflammatory Biomarkers

Background: Diagnosis of sepsis in burn patients remains difficult for various reasons. One major problem is the definition of sepsis itself. Therefore, previous and current sepsis definitions are a matter of ongoing validation, but a well-defined consensus on which clinical and laboratory parameters to incorporate in such a definition is lacking. The aim of the present study was to compare the incidence and time-related occurrence of septic events according to different definitions as well as their accompanying time course of pro-inflammatory biomarkers. Methods: Across the first 14 days after admission, the incidence and time point of sepsis according to three different definitions (Sepsis-3, Sepsis American Burns Association [ABA] 2007, Sepsis Zurich Burn Center) were assessed on a daily basis in adult burn patients with total body surface area (TBSA) ≥15% admitted to the Zurich Burn Center between May 2015 and October 2018. In order to investigate how well daily drawn proinflammatory biomarkers (white blood cells (WBCs), C-reactive protein (CRP), procalcitonin (PCT), and novel pancreatic stone protein (PSP)) reflect the progression of sepsis depending on its type of definition, a longitudinal mixed model analysis was performed across the first 14 days for septic and non-septic patients. Additionally, the relative increase of biomarker levels 24, 48, and 72 h prior to a septic event was analyzed for each definition used. Results: In our cohort of 90 severely burned patients, Sepsis-3 identified 46 patients (51.1%) as septic, while ABA 2007 and the Zurich Burn Center definition counted 33 patients (36.7%) and 24 patients (26.6%), respectively. Sepsis-3 detected sepsis about 1 day earlier than Sepsis ABA 2007 (p < 0.001) and about 0.5 days earlier than Sepsis Zurich Burn Center (p = 0.04). The course of pro-inflammatory biomarkers was largely unaffected by the type of sepsis definition. Irrespective of the sepsis definition, PSP was the only marker to demonstrate a highly significant interaction between time and group (sepsis versus no sepsis) (p < 0.001) with a 3.3–5.5-fold increase within 72 h before the event of sepsis, whereas CRP, PCT, and WBC showed only mild undulations. Conclusions: Despite the ongoing dilemma of how to define sepsis in burn patients, a continually calculated SOFA score as used in Sepsis-3 is advantageous to early identify a patient’s detrimental progression to sepsis. Inclusion of biomarkers, such as PSP, may help support the burn specialist’s diagnosis of sepsis and could improve the diagnostic performance of current and future definitions in burn patients.

Accuracy of pancreatic stone protein for the diagnosis of infection in hospitalized adults: a systematic review and individual patient level meta-analysis

Background

Accurate biomarkers to diagnose infection are lacking. Studies reported good performance of pancreatic stone protein (PSP) to detect infection. The objective of the study was to determine the performance of PSP in diagnosing infection across hospitalized patients and calculate a threshold value for that purpose.

Methods

A systematic search across Cochrane Central Register of Controlled Trials and MEDLINE databases (1966–March 2019) for studies on PSP published in English using ‘pancreatic stone protein’, ‘PSP’, ‘regenerative protein’, ‘lithostatin’ combined with ‘infection’ and ‘sepsis’ found 44 records. The search was restricted to the five trials that evaluated PSP for the initial detection of infection in hospitalized adults. Individual patient data were obtained from the investigators of all eligible trials. Data quality and validity was assessed according to PRISMA guidelines. We choose a fixed-effect model to calculate the PSP cut-off value that best discriminates infected from non-infected patients.

Results

Infection was confirmed in 371 of 631 patients. The median (IQR) PSP value of infected versus uninfected patients was 81.5 (30.0–237.5) versus 19.2 (12.6–33.57) ng/ml, compared to 150 (82.70–229.55) versus 58.25 (15.85–120) mg/l for C-reactive protein (CRP) and 0.9 (0.29–4.4) versus 0.15 (0.08–0.5) ng/ml for procalcitonin (PCT). Using a PSP cut-off of 44.18 ng/ml, the ROC AUC to detect infection was 0.81 (0.78–0.85) with a sensitivity of 0.66 (0.61–0.71), specificity of 0.83 (0.78–0.88), PPV of 0.85 (0.81–0.89) and NPV of 0.63 (0.58–0.68). When a model combining PSP and CRP was used, the ROC AUC improved to 0.90 (0.87–0.92) with higher sensitivity 0.81 (0.77–0.85) and specificity 0.84 (0.79–0.90) for discriminating infection from non-infection. Adding PCT did not improve the performance further.

Conclusions

PSP is a promising biomarker to diagnose infections in hospitalized patients. Using a cut-off value of 44.18 ng/ml, PSP performs better than CRP or PCT across the considered studies. The combination of PSP with CRP further enhances its accuracy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03609-2.

PCT Kinetics in the First Week Postburn for Sepsis Diagnosis and Death Prognosis-An Accuracy Study

Despite continuous advances in burn care, sepsis is still the main cause of death in burn patients. Procalcitonin (PCT) has been reported as an accurate sepsis biomarker and also as a fair predictor of death. The aim of this study was to assess PCT kinetics in the first week postburn regarding sepsis diagnosis and death prognosis. Sample included 142 patients with ≥15% TBSA, admitted from January 2011 to December 2014 at Coimbra Burns Unit, Portugal. Sepsis diagnosis was done according to American Burn Association criteria. PCT range and median values in the first 7 days after burns were statistically analyzed for its potential for sepsis diagnosis and death prognosis. A subanalysis was done regarding TBSA, sex, age, and inhalation injury. First week PCT range and median were significant for sepsis diagnosis and death prognosis, but the median area under the curve was greater in the last case. TBSA influenced PCT accuracy, which was greater for TBSA less than 40% either for diagnosis or prognosis. Age was inversely related to the accuracy, being better in younger than 40 years in both cases. PCT diagnostic accuracy was not affected by sex, opposing to the prognostic one which is better in women. Inhalation injury had no effect on diagnostic accuracy, but it happens with prognostic accuracy. PCT levels' variation is related to sepsis evolution and outcome. Its median performs better than its range. Always coupled with clinical examination, monitoring PCT levels kinetics may help early sepsis detection, potentially reducing morbidity and mortality, being also useful for death prognosis.