Prognostic performance of pancreatic stone protein in critically ill patients with sepsis

The Possible Pathophysiological Role of Pancreatic Stone Protein in Sepsis and Its Potential Therapeutic Implication

According to the current understanding of the pathophysiology of sepsis, key host dysregulated responses leading to organ failure are mediated by innate immunity, through interactions between pathogen-associated molecular patterns (PAMPs) and damaged-associated molecular patterns (DAMPs) binding to four types of pattern recognition receptors (PRRs). PRRs activation triggers the protein kinase cascade, initiating the cellular response seen during sepsis. Pancreatic stone protein (PSP), a C-type lectin protein, is a well-defined biomarker of sepsis. Studies have shown that stressed and immune-activated pancreatic β-cells secrete PSP. Animal studies have shown that PSP injection aggravates sepsis, and that the disease severity score and mortality were directly correlated with the doses of PSP injected. In humans, studies have shown that PSP activates polymorphonuclear neutrophils (PMNs) and aggravates multiple organ dysfunction syndrome. Clinical studies have shown that PSP levels are correlated with disease severity, vasopressor support, progression to organ failure, mechanical ventilation, renal replacement therapy, length of stay, and mortality. As PSP is a C-type lectin protein, it may have a role in activating innate immunity through the C-type lectin receptors (CLRs), which is one of the four PRRs. Herein, we review the literature on PSP and its possible role in the pathophysiology of sepsis, and we discuss its potential therapeutic role.

Mortality prediction model from combined serial lactate, procalcitonin and calprotectin levels in critically ill patients with sepsis: A retrospective study according to Sepsis-3 definition

OBJECTIVE

1) To evaluate the ability of baseline and on 24 h serum calprotectin, in comparison to canonical biomarkers (lactate and procalcitonin), for prognosis of 28-day mortality in critically ill septic patients; and 2) To develop a predictive model combining the three biomarkers.

DESIGN

A single-center, retrospective study.

SETTING

Intensive Care Unit of a university hospital.

PATIENTS OR PARTICIPANTS

One hundred and seventy three septic pacientes were included.

INTERVENTIONS

Measurement of baseline lactate, procalcitonin and calprotectin level and procalcitonin and calprotectin levels on 24 h.

MAIN VARIABLES OF INTEREST

Demographics and comorbidities, SOFA score on ICU admission, baseline lactate, procalcitonin and calprotectin on admission and on 24 h and 28-day mortality.

RESULTS

1) On ICU admission, lactate was the only biomarker achieving a significant accuracy (AUC: 0.698); 2) On 24 h, no differences were found on procalcitonin and calprotectin levels. Procalcitonin and calprotectin clearances were significantly lower in non-survivors and both achieved a moderate performance (AUCs: 0.668 and 0.664, respectively); 3) A biomarker based-model achieved a significant accuracy (AUC: 0.766), trending to increase (AUC: 0.829) to SOFA score alone; y 4) Baseline lactate levels and procalcitonin and calprotectin clearance were independent predictors for the outcome.

CONCLUSIONS

1) Baseline and on 24 h calprotectina and procalcitonin levels lacked ability in predicting 28-day mortality; 2) Accuracy of clearance of both biomarkers was moderate; and 3) Combination of SOFA score and the predictive biomarker based-model showed a high prognostic accuracy.

Diagnostic and Prognostic Ability of Pancreatic Stone Protein: A Scoping Review

Pancreatic stone protein (PSP) is an acute-phase reactant mainly produced in response to stress. Its diagnostic and prognostic accuracy for several types of infection has been studied in several clinical settings. The aim of the current review was to assess all studies examining a possible connection of pancreatic stone protein levels with the severity and possible complications of patients diagnosed with infection. We performed a systematic search in PubMed, Scopus, the Cochrane Library and Clinicaltrials.gov to identify original clinical studies assessing the role of pancreatic stone protein in the diagnosis and prognosis of infectious diseases. We identified 22 eligible studies. Ten of them provided diagnostic aspects, ten studies provided prognostic aspects, and another two studies provided both diagnostic and prognostic information. The majority of the studies were performed in an intensive care unit (ICU) setting, five studies were on patients who visited the emergency department (ED), and three studies were on burn-injury patients. According to the literature, pancreatic stone protein has been utilized in patients with different sites of infection, including pneumonia, soft tissue infections, intra-abdominal infections, urinary tract infections, and sepsis. In conclusion, PSP appears to be a useful point-of-care biomarker for the ED and ICU due to its ability to recognize bacterial infections and sepsis early. Further studies are required to examine PSP's kinetics and utility in specific populations and conditions.

Examining pancreatic stone protein response in ICU-acquired bloodstream infections: a matched event analysis

BACKGROUND

Pancreatic stone protein (PSP) exhibits potential as a plasma biomarker for infection diagnosis and risk stratification in critically ill patients, but its significance in nosocomial infection and intensive care unit (ICU)-acquired bloodstream infection (BSI) remains unclear. This study explores the temporal responses of PSP in ICU-acquired BSI caused by different pathogens.

METHODS

From a large cohort of ICU patients, we selected episodes of ICU-acquired BSI caused by Gram-negative rods (GNRs), enterococci, or Candida species. Events were matched on length of ICU stay at infection onset, Severe Organ Failure Assessment (SOFA) score, presence of immune deficiency, and use of renal replacement therapy. PSP concentrations were measured at infection onset (T0) and at 24, 48 and 72 h prior to infection onset as defined by the first occurrence of a positive blood culture. Absolute and trend differences in PSP levels between pathogen groups were analysed using one-way analysis of variance. Sensitivity analyses were performed in events with a new or worsening systematic inflammatory response based on C-reactive protein, white cell count and fever.

RESULTS

We analysed 30 BSI cases per pathogen group. Median (IQR) BSI onset was on day 9 (6-12). Overall, PSP levels were high (381 (237-539) ng/ml), with 18% of values exceeding the assay's measurement range. Across all 90 BSI cases, there was no clear trend over time (median change 34 (- 75-189) ng/ml from T-72 to T0). PSP concentrations at infection onset were 406 (229-497), 350 (223-608), and 480 (327-965) ng/ml, for GNR, enterococci, and Candida species, respectively (p = 0.32). At every time point, absolute PSP levels and trends did not differ significantly between pathogens. PSP values at T0 correlated with SOFA scores. Eighteen (20%) of 90 BSI events did not exhibit a systemic inflammatory response, primarily in Candida species. No clear change in PSP concentration before BSI onset or between-group differences were found in sensitivity analyses of 72 cases.

CONCLUSIONS

Against a background of overall (very) high plasma PSP levels in critically ill patients, we did not find clear temporal patterns or any pathogen-specific differences in PSP response in the days preceding onset of ICU-acquired BSI.

The Role of the Pancreatic Stone Protein in Predicting Intra-Abdominal Infection-Related Complications: A Prospective Observational Single-Center Cohort Study

BACKGROUND

The Pancreatic Stone Protein (PSP) is an acute-phase protein that is mainly secreted by pancreatic cells in response to stress. The current literature supports its use as a predictor of sepsis. Its prognostic role has recently been evaluated in a point-of-care setting, mostly in high-risk patients. We conducted a prospective observational cohort study to evaluate its utility in the prognosis of patients admitted to the hospital with a diagnosis of intra-abdominal infection.

METHODS

Adult patients consecutively admitted to the Internal Medicine Department of the University Hospital of Patras, Greece, with a diagnosis of intra-abdominal infection were enrolled. PSP levels were measured within 24 h of admission in whole blood.

RESULTS

a total of 40 patients were included after being diagnosed with IAI. PSP was used as an independent predictive factor for sepsis after adjusting for age with OR = 7.888 (95% CI: 1.247-49.890). PSP also predicted readmission and the need for treatment escalation (p: <0.01) and was an excellent prognostic factor regarding these outcomes (AUC = 0.899, 95% CI: 0.794-1.0, and AUC = 0.862, 95% CI: 0.748-0.976, respectively). PSP also proved superior to CRP, ferritin, and fibrinogen in sepsis diagnosis, treatment escalation, and readmission prediction with an AUC of 0.862, 0.698, and 0.899, respectively.

CONCLUSIONS

PSP can predict unfavorable outcomes, such as sepsis development, readmission, and the need for treatment escalation among patients with intra-abdominal infections.

Evaluation of the Kinetics of Pancreatic Stone Protein as a Predictor of Ventilator-Associated Pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is a severe condition. Early and adequate antibiotic treatment is the most important strategy for improving prognosis. Pancreatic Stone Protein (PSP) has been described as a biomarker that increases values 3-4 days before the clinical diagnosis of nosocomial sepsis in different clinical settings. We hypothesized that serial measures of PSP and its kinetics allow for an early diagnosis of VAP.

METHODS

The BioVAP study was a prospective observational study designed to evaluate the role of biomarker dynamics in the diagnosis of VAP. To determine the association between repeatedly measured PSP and the risk of VAP, we used joint models for longitudinal and time-to-event data.

RESULTS

Of 209 patients, 43 (20.6%) patients developed VAP, with a median time of 4 days. Multivariate joint models with PSP, CRP, and PCT did not show an association between biomarkers and VAP for the daily absolute value, with a hazard ratio (HR) for PSP of 1.01 (95% credible interval: 0.97 to 1.05), for CRP of 1.00 (0.83 to 1.22), and for PCT of 0.95 (0.82 to 1.08). The daily change of biomarkers provided similar results, with an HR for PSP of 1.15 (0.94 to 1.41), for CRP of 0.76 (0.35 to 1.58), and for PCT of 0.77 (0.40 to 1.45).

CONCLUSION

Neither absolute PSP values nor PSP kinetics alone nor in combination with other biomarkers were useful in improving the prediction diagnosis accuracy in patients with VAP.

CLINICAL TRIAL REGISTRATION

Registered retrospectively on August 3rd, 2012. NCT02078999.

Point-of-care pancreatic stone protein measurement in critically ill COVID-19 patients

INTRODUCTION

Pancreatic stone protein (PSP) is a novel biomarker that is reported to be increased in pneumonia and acute conditions. The primary aim of this study was to prospectively study plasma levels of PSP in a COVID-19 intensive care unit (ICU) population to determine how well PSP performed as a marker of mortality in comparison to other plasma biomarkers, such as C reactive protein (CRP) and procalcitonin (PCT).

METHODS

We collected clinical data and blood samples from COVID-19 ICU patients at the time of admission (T0), 72 h later (T1), five days later (T2), and finally, seven days later. The PSP plasma level was measured with a point-of-care system; PCT and CRP levels were measured simultaneously with laboratory tests. The inclusion criteria were being a critical COVID-19 ICU patient requiring ventilatory mechanical assistance.

RESULTS

We enrolled 21 patients and evaluated 80 blood samples; we found an increase in PSP plasma levels according to mixed model analysis over time (p < 0.001), with higher levels found in the nonsurvivor population (p < 0.001). Plasma PSP levels achieved a statistically significant result in terms of the AUROC, with a value higher than 0.7 at T0, T1, T2, and T3. The overall AUROC of PSP was 0.8271 (CI (0.73-0.93), p < 0.001). These results were not observed for CRP and PCT.

CONCLUSION

These first results suggest the potential advantages of monitoring PSP plasma levels through point-of-care technology, which could be useful in the absence of a specific COVID-19 biomarker. Additional data are needed to confirm these results.

The Role of Pancreatic Stone Protein (PSP) as a Biomarker of Pregnancy-Related Diseases

Background: Pancreatic stone protein (PSP) is a biochemical serum marker that contains levels that are elevated in various inflammatory and infectious diseases. The role of PSP in the diagnosis of these diseases seems to be more important compared to clinically established biochemical serum markers in discriminating the severity of the same diseases. Standard values for PSP in pregnant women in relation to gestational age have been reported recently. Additionally, increased PSP levels have been observed to be associated with renal dysfunction in pregnant women. The aim of this study is to evaluate the diagnostic role of PSP in pregnancy-related diseases, such as pre-eclampsia (PE), hemolysis-elevated liver enzymes, and low platelet (HELLP) syndrome. In addition, the study aims to assess its diagnostic role in inflammation-triggered diseases as preterm premature rupture of membranes (PPROM) or COVID-19-positive pregnant women. Materials and Methods: In this single-centred prospective study performed at a tertiary university hospital between 2013 and 2021, we included 152 pregnant women who were diagnosed with either PE, HELLP syndrome, or PPROM. In December 2020, in the context of the COVID-19 pandemic, the Independent Ethics Committee (IEC) approved an amendment to the study protocol. Depending on the underlying disease, single or serial-serum PSP measurements were assessed. These PSP values were compared to PSP levels of women with normal pregnancies. Results: Pregnant women diagnosed with pre-eclampsia or HELLP syndrome had significantly increased PSP values (mean 9.8 ng/mL, SD 2.6) compared to healthy singleton pregnant women (mean 7.9 ng/mL, SD 2.6, p ≤ 0.001). There was no difference in serum PSP in pregnant women with PPROM compared to women with uncomplicated singleton pregnancies (mean in PPROM: 7.9 ng/mL; SD 2.9 versus mean in healthy pregnancies: 7.9 ng/mL; SD 2.6, p = 0.98). Furthermore, no difference in the PSP values in women with or without intra-amniotic infection was observed (infection: mean 7.9 ng/mL; SD 2.8 versus no infection: mean 7.8 ng/mL; SD 3, p = 0.85). The mean value of PSP in COVID-19-infected women during pregnancy (8.5 ng/mL, SD 2.3) was comparable to healthy singleton pregnancies (mean 7.9 ng/mL, SD 2.6), p = 0.24. Conclusions: The novel serum biomarker PSP is significantly upregulated in pregnant women with pre-eclampsia and HELLP syndrome. Our observations call for the further evaluation of PSP in randomized controlled clinical trials to demonstrate the actual role of PSP in pregnancy-related diseases and whether it may provide new approaches for the management and discrimination of the severity of these gestational conditions.

Serum Pancreatic Stone Protein Reference Values in Healthy Pregnant Women: A Prospective Cohort Study

BACKGROUND

In non-pregnant populations, pancreatic stone protein (PSP) has been reported to have a higher diagnostic performance for identifying severe inflammatory and infectious disease than other established biomarkers.

OBJECTIVE

To generate reference values for serum PSP in pregnancy and compare them to the values of the general healthy population.

DESIGN

A prospective cohort study.

SETTING

A single center.

POPULATION

Healthy women with singleton and multiple pregnancies.

METHODS

This is a prospective single-center cohort study. Between 2013 and 2021, samples of 5 mL peripheral blood were drawn from 440 healthy pregnant women. Therein, 393 cases were singletons and 47 were multiple pregnancies. Serum PSP levels were measured by specific enzyme-linked immunosorbent assay. The main outcome measures were serum PSP level (ng/mL) reference values in healthy pregnant women.

RESULTS

The mean PSP reference values in women with singleton pregnancies were 7.9 ± 2.6 ng/mL (95% CI; 2.69-13.03 ng/mL). The PSP values in women with multiple pregnancies (9.17 ± 3.06 ng/mL (95% CI; 3.05-15.28 ng/mL)) were significantly higher (p = 0.001). The PSP values in the first trimester (6.94 ± 2.53 ng/mL) were lower compared to the second (7.42 ± 2.21 ng/mL) and third trimesters (8.33 ± 2.68 ng/mL, p = 0.0001). Subgroup analyses in singletons revealed no correlations between PSP values, maternal characteristics, and pre-existing medical conditions.

CONCLUSION

The PSP values in healthy pregnant women (4-12 ng/mL) were in the range of the reference values of the general healthy population (8-16 ng/mL). This insight blazes a trail for further clinical studies on the use of PSP as a potential novel biomarker for the early detection of pregnancy-related diseases such as chorioamnionitis.

Pediatric sepsis diagnostic and prognostic biomarkers: pancreatic stone protein, copeptin, and apolipoprotein A-V

BACKGROUND

We assessed serum concentrations of pancreatic stone protein (PSP), copeptin, and apolipoprotein A-V (APOA5) biomarkers for the diagnosis and prognosis of pediatric sepsis, a condition associated with high mortality.

METHODS

This prospective study included 180 children admitted to the Pediatric Intensive Care Unit and 100 healthy controls at Menoufia University Hospital. Pediatric Risk of Mortality (PRISM), Pediatric Index of Mortality-2 (PIM2), and Pediatric Sequential Organ Failure Assessment (pSOFA) scores were calculated. Serum PSP, copeptin and APOA5 were measured once within 24 h of admission.

RESULTS

PSP, copeptin, and APOA5 were significantly higher in the patients than in the controls (p < 0.001). PSP and copeptin were increased among children who required mechanical ventilation (MV), had multiple organ dysfunctions, and were non-survivors, but APOA5 was decreased in those children. Logistic regression analyses showed that high pSOFA, high PSP and copeptin, low APOA5, and use of MV were associated with mortality. The receiver operating characteristic revealed that the area under the curve (AUC) for APOA5, copeptin, and PSP (0.965, 0.960, and 0.868, respectively) demonstrated high sensitivity (96%, 94%, and 80%) for sepsis diagnosis. The AUC values for PSP, copeptin, and APOA5 were 0.709, 0.705, and 0.571, respectively, with sensitivities of 74%, 58%, and 58% for mortality prediction.

CONCLUSIONS

PSP, copeptin, and APOA5 are promising diagnostic biomarkers for pediatric sepsis but inadequate predictors of mortality.

IMPACT

Apolipoprotein A-V (APOA5), copeptin, and pancreatic stone protein (PSP) are acute-phase proteins with diagnostic value in evaluating critically ill pediatric patients with sepsis and detecting sepsis severity. PSP and copeptin had the power to discriminate non-survivors from survivors. APOA5 was less powerful than the other biomarkers in discriminating between survivors and non-survivors.

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.

Role of Pancreatic Stone Protein as an Early Biomarker for Risk Stratification of Acute Pancreatitis

BACKGROUND

Early risk stratification of acute pancreatitis is crucial to improve clinical outcomes. The objective of this study was to evaluate the ability of pancreatic stone protein (PSP) to predict acute pancreatitis severity and to compare it with the biomarkers and severity scores currently used for that purpose.

PATIENTS AND METHODS

Prospective single-center observational study enrolling 268 adult patients with acute pancreatitis. Biomarkers including PSP were measured upon admission to the Emergency Department and severity scores as SOFA, PANC-3, and BISAP were computed. Patients were classified into mild-moderate (non-severe) and severe acute pancreatitis according to the Determinant-Based Classification Criteria. Area under the curve (AUC) and regression analysis were used to analyze the discrimination abilities and the association of biomarkers and scores with severity.

RESULTS

Two hundred and thirty-five patients (87.7%) were classified as non-severe and 33 (12.3%) as severe acute pancreatitis. Median [IQR] PSP was increased in patients with severe acute pancreatitis (890 μg/L [559-1142] vs. 279 μg/L [141-496]; p < 0.001) and it was the best predictor (ROC AUC: 0.827). In multivariate analysis, PSP and urea were the only independent predictors for severe acute pancreatitis and a model combining them both ("biomarker model") showed an AUC of 0.841 for prediction of severe acute pancreatitis, higher than the other severity scores.

CONCLUSIONS

PSP is a promising biomarker for predicting the severity of acute pancreatitis upon admission. A model combining PSP and urea might further constitute a potential tool for early risk stratification of this disease.

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.

Serial measurement of pancreatic stone protein for the early detection of sepsis in intensive care unit patients: a prospective multicentric study

Background

The early recognition and management of sepsis improves outcomes. Biomarkers may help in identifying earlier sub-clinical signs of sepsis. We explored the potential of serial measurements of C-reactive protein (CRP), procalcitonin (PCT) and pancreatic stone protein (PSP) for the early recognition of sepsis in patients hospitalized in the intensive care unit (ICU).

Methods

This was a multicentric international prospective observational clinical study conducted in 14 ICUs in France, Switzerland, Italy, and the United Kingdom. Adult ICU patients at risk of nosocomial sepsis were included. A biomarker-blinded adjudication committee identified sepsis events and the days on which they began. The association of clinical sepsis diagnoses with the trajectories of PSP, CRP, and PCT in the 3 days preceding these diagnoses of sepsis were tested for markers of early sepsis detection. The performance of the biomarkers in sepsis diagnosis was assessed by receiver operating characteristic (ROC) analysis.

Results

Of the 243 patients included, 53 developed nosocomial sepsis after a median of 6 days (interquartile range, 3–8 days). Clinical sepsis diagnosis was associated with an increase in biomarkers value over the 3 days preceding this diagnosis [PSP (p = 0.003), PCT (p = 0.025) and CRP (p = 0.009)]. PSP started to increase 5 days before the clinical diagnosis of sepsis, PCT 3 and CRP 2 days, respectively. The area under the ROC curve at the time of clinical sepsis was similar for all markers (PSP, 0.75; CRP, 0.77; PCT, 0.75).

Conclusions

While the diagnostic accuracy of PSP, CRP and PCT for sepsis were similar in this cohort, serial PSP measurement demonstrated an increase of this marker the days preceding the onset of signs necessary to clinical diagnose sepsis. This observation justifies further evaluation of the potential clinical benefit of serial PSP measurement in the management of critically ill patients developing nosocomial sepsis.

Trial registration The study has been registered at ClinicalTrials.gov (no. NCT03474809), on March 16, 2018. https://www.clinicaltrials.gov/ct2/show/NCT03474809?term=NCT03474809&draw=2&rank=1.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03576-8.