Mortality is increased by procalcitonin and decreased by an antiserum reactive to procalcitonin in experimental sepsis

Procalcitonin has bioactivity at calcitonin receptor family complexes: potential mediator implications in sepsis

CONTEXT

Sepsis is a major cause of death in the United States and accounts for approximately 50% of the fatalities in intensive care units. Serum procalcitonin (ProCT) levels are markedly elevated in sepsis and correlate positively with severity of the illness and mortality, however, little is known about the biological activity of ProCT.

OBJECTIVE

To explore the biological activity of purified human ProCT at the calcitonin (CT) family of receptors.

DESIGN

Human ProCT was purified from the TT medullary thyroid carcinoma cell line. Human CTa receptor or human CT receptor-like receptor (CLR) was transiently expressed in COS-7 cells alone or together with individual receptor activity-modifying proteins (RAMPs) to generate the CTa (CT) receptor, the AMY1 (amylin) receptor, the CGRP1 (CT gene-related peptide) receptor, and the AM1 and AM2 (adrenomedullin) receptors. Biological activity of ProCT was assessed by measurement of cAMP accumulation.

RESULTS

ProCT was effectively inert at CTa, AM1, and AM2 receptors. In contrast, it was a potent partial agonist (50-60% of the CGRP efficacy) of the CGRP1 receptor with an EC50 as high as 0.56 nM, although the potency was batch dependent. ProCT also displayed weak partial agonist activity at the AMY1 receptor with an EC50 of approximately 100 nM. Moreover, ProCT also robustly inhibited CGRP-dependent cyclic adenosine monophosphate responses at the CGRP1 receptor.

CONCLUSIONS

Our data provide a potential molecular mechanism for the observation that ProCT appears to be toxic while CGRP treatment appears to be beneficial in animal models of sepsis.

Procalcitonin assay in systemic inflammation, infection, and sepsis: clinical utility and limitations

OBJECTIVE

The use of procalcitonin (ProCT) as a marker of several clinical conditions, in particular, systemic inflammation, infection, and sepsis, will be clarified, and its current limitations will be delineated. In particular, the need for a more sensitive assay will be emphasized. For these purposes, the medical literature comprising clinical studies pertaining to the measurement of serum ProCT in various clinical settings was examined.

DATA SOURCE AND SELECTION

A PubMed search (1965 through November 2007) was conducted, including manual cross-referencing. Pertinent complete publications were obtained using the MeSH terms procalcitonin, C-reactive protein, sepsis, and biological markers. Textbook chapters were also read and extracted.

DATA EXTRACTION AND SYNTHESIS

Available clinical and other patient data from these sources were reviewed, including any data relating to precipitating factors, clinical findings, associated illnesses, and patient outcome. Published data concerning sensitivity, specificity, and reproducibility of ProCT assays were reviewed.

CONCLUSIONS

Based on available data, the measurement of serum ProCT has definite utility as a marker of severe systemic inflammation, infection, and sepsis. However, publications concerning its diagnostic and prognostic utility are contradictory. In addition, patient characteristics and clinical settings vary markedly, and the data have been difficult to interpret and often extrapolated inappropriately to clinical usage. Furthermore, attempts at meta-analyses are greatly compromised by the divergent circumstances of reported studies and by the sparsity and different timing of the ProCT assays. Although a high ProCT commonly occurs in infection, it is also elevated in some noninfectious conditions. Thus, the test is not a specific indicator of either infection or sepsis. Moreover, in any individual patient, the precipitating cause of an illness, the clinical milieu, and complicating conditions may render tenuous any reliable estimations of severity or prognosis. It also is apparent that even a febrile septic patient with documented bacteremia may not necessarily have a serum ProCT that is elevated above the limit of functional sensitivity of the assay. In this regard, the most commonly applied assay (i.e., LUMItest) is insufficiently sensitive to detect potentially important mild elevations or trends. Clinical studies with a more sensitive ProCT assay that is capable of rapid and practicable day-to-day monitoring are needed and shortly may be available. In addition, investigations showing that ProCT and its related peptides may have mediator relevance point to the need for evaluating therapeutic countermeasures and studying the pathophysiologic effect of hyperprocalcitonemia in serious infection and sepsis.

Induction of procalcitonin in liver transplant patients treated with anti-thymocyte globulin

Introduction

The aim of this study was to compare the early postoperative kinetics of procalcitonin (PCT) and C-reactive protein (CRP) serum levels in patients undergoing orthotopic liver transplantation (OLTx) with different immunosuppressive regimens.

Methods

PCT and CRP serum concentrations were measured in a group of 28 OLTx recipients before induction of anesthesia, at 4 and 8 hours following graft reperfusion, and daily until postoperative day 4. The same parameters were determined in 12 patients undergoing liver resection without conjunctive immunosuppressive therapy. Summary data are expressed as medians and ranges. Two-tailed nonparametric tests were performed and considered significant at p values of less than 0.05.

Results

The highest serum levels of PCT (median 3.0 ng/mL, minimum 1.4 ng/mL, maximum 13.9 ng/mL) were found in patients after OLTx without ATG therapy, on postoperative day 1. In patients with ATG administration, PCT levels were highly increased on postoperative day 1 (median 53.0 ng/mL, minimum 7.9 ng/mL, maximum 249.1 ng/mL). Thereafter, PCT values continuously decreased independently of further ATG administration in both groups of patients. No evidence of infection was present in either group. In 12 patients undergoing liver resection, peak serum PCT levels did not exceed 3.6 ng/mL. CRP serum levels in a group of patients with and without ATG therapy increased significantly on postoperative day 1, followed by a decrease. The highest levels of CRP were found in patients after liver resection on postoperative day 2 and decreased thereafter.

Conclusion

ATG administration to patients with OLTx is associated with an increase in serum PCT levels, with peak values on postoperative day 1, and this was in the absence of any evidence of infection. The results of this study indicate that ATG immunosuppressive therapy is a stimulus for the synthesis of PCT.

A comparison of high-mobility group-box 1 protein, lipopolysaccharide-binding protein and procalcitonin in severe community-acquired infections and bacteraemia: a prospective study

Introduction

High-mobility group box-1 protein (HMGB1) has been known as a chromosomal protein for many years. HMGB1 has recently been shown to be a proinflammatory cytokine with a role in the immunopathogenesis of sepsis. Lipopolysaccharide-binding protein (LBP) has a central role in the innate immune response when the host is challenged by bacterial pathogens. Procalcitonin (PCT) has been suggested as a marker of severe bacterial infections and sepsis. The aim of the present study was to investigate levels of HMGB1, LBP and PCT in a well-characterised sepsis cohort. The study plan included analysis of the levels of the inflammatory markers in relation to the severity of infection, to the prognosis and to the ability to identify patients with bacteraemia.

Methods

Patients suspected of having severe infections and admitted to a department of internal medicine were included in a prospective manner. Demographic data, comorbidity, routine biochemistry, microbiological data, infection focus, severity score and mortality on day 28 were recorded. Plasma and serum were sampled within 24 hours after admission. Levels of all studied markers (HMGB1, LBP, PCT, IL-6, C-reactive protein, white blood cell count and neutrophils) were measured with commercially available laboratory techniques.

Results

A total of 185 adult patients were included in the study; 154 patients fulfilled our definition of infection. Levels of HMGB1, LBP and PCT were higher in infected patients compared with a healthy control group (P < 0.0001). Levels of HMGB1, LBP and PCT were higher in the severe sepsis group compared with the sepsis group (P < 0.01). No differences were observed in levels of the inflammatory markers in fatal cases compared with survivors. Levels of all studied markers were higher in bacteraemic patients compared with nonbacteraemic patients (P < 0.05). PCT performed best in a receiver–operator curve analysis discriminating between bacteraemic and nonbacteraemic patients (P < 0.05). HMGB1 correlated to LBP, IL-6, C-reactive protein, white blood cell count and neutrophils (P < 0.001). LBP correlated to PCT, IL-6 and C-reactive protein (P < 0.001).

Conclusion

Levels of HMGB1, PCT and LBP were higher in infected patients compared with those in healthy controls, and levels were higher in severe sepsis patients compared with those in sepsis patients. Levels of all studied inflammatory markers (HMGB1, LBP, PCT, IL-6) and infection markers (C-reactive protein, white blood cell count, neutrophils) were elevated among bacteraemic patients. PCT performed best as a diagnostic test marker for bacteraemia.

Correlation of procalcitonin and cytokine expression with dehiscence of wartime extremity wounds

BACKGROUND

Despite technological advances in the treatment of severe extremity trauma, the timing of wound closure remains the subjective clinical decision of the treating surgeon. Traditional serum markers are poor predictors of wound-healing. The objective of this study was to evaluate the cytokine and chemokine profiles of severe extremity wounds prior to closure to determine if wound effluent markers can be used to predict healing.

METHODS

Serum and effluent (exudate) samples were collected prospectively from adult volunteers with multiple high-energy penetrating extremity wounds sustained during military combat. Samples were collected prior to definitive wound closure or flap coverage. Wounds were followed clinically for six weeks. The primary clinical outcome measures were wound-healing and dehiscence. Control serum samples were collected from normal age and sex-matched adult volunteers. All samples were analyzed for the following cytokines and chemokines: procalcitonin; eotaxin; granulocyte macrophage colony stimulating factor; interferon (IFN)-gamma; interleukin (IL)-1 through 8, 10, 12, 13, and 15; IFN-gamma inducible protein-10; monocyte chemotactic protein-1; macrophage inflammatory protein-1alpha; the protein regulated on activation, normal T expressed and secreted (RANTES); and tumor necrosis factor (TNF)-alpha.

RESULTS

Fifty wounds were analyzed in twenty patients. Four of the fifty wounds dehisced. An increased rate of wound dehiscence was observed in patients with a concomitant closed head injury as well as in those with an associated arterial injury of the affected limb (p < 0.05). Among the serum chemokines and cytokines, only serum procalcitonin levels correlated with wound dehiscence (p < 0.05). Effluent analysis showed that, compared with wounds that healed, wounds that dehisced were associated with elevated procalcitonin, decreased RANTES protein, and decreased IL-13 concentrations (p < 0.05). No wound with an effluent procalcitonin concentration of <220 pg/mL, an IL-13 concentration of >12 pg/mL, or a RANTES protein concentration of >1000 pg/mL failed to heal.

CONCLUSIONS

Effluent procalcitonin, IL-13, and RANTES protein levels as well as serum procalcitonin levels correlate with wound dehiscence following closure of severe open extremity wounds. These preliminary results indicate that effluent biomarker analysis may be an objective means of determining the timing of traumatic wound closure.

New immunological serum markers in bacteraemia: anti-inflammatory soluble CD163, but not proinflammatory high mobility group-box 1 protein, is related to prognosis

High mobility group-box 1 protein (HMGB1) is a late-onset proinflammatory cytokine. Soluble haemoglobin scavenger receptor (sCD163) is a specific marker of anti-inflammatory macrophages. The study purpose was to relate the levels of these new markers in bactaeremic patients to levels of well-known pro- and anti-inflammatory markers [procalcitonin, lipopolysaccharide (LPS)-binding protein, interleukin (IL)-6, IL-10] and to evaluate the levels in relation to disease severity and aetiology. A total of 110 patients with bacteraemia were included in a prospective manner from the medical department at a large Danish university hospital. Levels of HMGB1 and sCD163 were higher in patients with bacteraemia compared to controls (P < 0.001). HMGB1 correlated with proinflammatory molecules [procalcitonin (PCT)] and traditional infectious parameters [C-reactive proteins (CRP), white blood cells (WBC) and neutrophils], whereas sCD163 correlated with levels of IL-6, IL-10 but not to lipopolysaccharide-binding protein (LBP), PCT or CRP. Levels of sCD163 and IL-6 were significantly higher among non-survivors compared to survivors (P < 0.05). Neither HMGB1 nor any of the proinflammatory markers were elevated in fatal cases compared to survivors. There was no statistically significant difference in HMGB1 and sCD163 levels in Gram-negative versus Gram-positive bacteraemia. HMGB1 reflects proinflammatory processes, whereas sCD163 reflects anti-inflammatory processes as judged by correlations with traditional marker molecules. sCD163 and IL-6, but not HMGB1, were prognostic markers in this cohort pointing to an anti-inflammatory predominance in patients with fatal disease outcome.

Plasma procalcitonin measured by time-resolved amplified cryptate emission (TRACE) in liver transplant patients. A prognosis marker of early infectious and non-infectious postoperative complications

BACKGROUND

Elevated procalcitonin (PCT) levels are observed after major surgery, such as orthotopic liver transplantation (OLTx). The aim of this observational study was to evaluate PCT kinetics during the first 5 following days after surgery to establish the prognostic value of PCT changes in the outcome of OLTx, and to predict medical, technical and infectious complications. PCT was also evaluated in the differential diagnosis of infection vs. rejection.

METHODS

A total of 64 OLTx were performed in 58 patients; they were split into two groups: with and without complications. Out of these patients, 18 developed infection, and nine rejection. PCT was measured before and during surgery, 12 h after transplantation and daily for the 5 following days. PCT was also measured the day when infection or rejection was diagnosed, and on the previous day. PCT was determined by time-resolved amplified cryptate emission (TRACE) technology.

RESULTS

PCT elevation began at 12 h after surgery, reaching a peak on the 1st day in both groups. Significantly higher PCT concentrations were found in the group of patients developing complications, on the 5 postoperative days. It was found that a 24 h PCT value higher than 1.92 microg/L increased by 9.1-time-fold the risk of complications. When infection was diagnosed, a second peak of PCT was observed, but no PCT elevation was shown in rejection.

CONCLUSIONS

Daily monitored PCT provides valuable information about the early outcome of OLTx.

Procalcitonin for the clinical laboratory: a review

Procalcitonin measurement has been claimed as a helpful marker in bacterial infection and sepsis. It has obtained FDA approval and is now widely marketed in the United States and Europe. This review summarises the current assays available, the evidence for its use and possible future applications of the assay.

Biomarkers to improve diagnostic and prognostic accuracy in systemic infections

PURPOSE OF REVIEW

We review the advantages and drawbacks of biomarkers in the diagnostic and prognostic assessment of systemic infections.

RECENT FINDINGS

Since the signs and symptoms of severe infections can be ambiguous, biomarkers provide a more reliable tool in ascertaining the presence of a relevant bacterial infection, its severity and treatment response. Procalcitonin and, to a lesser extent, C-reactive protein and interleukin-8 can improve the diagnostic assessment of infections and guide antibiotic therapy. Promising prognostic biomarkers include cortisol, proadrenomedullin, copeptin and natriuretic peptides. The strengths and weaknesses of biomarkers must be recognized in order to use them rationally and safely. Cutoff ranges of biomarkers must be chosen according to the specific clinical context and they should be used as a complementary tool, to reinforce the clinical diagnostic workup. Biomarkers cannot determine the causative organisms and associated patterns of antibiotic susceptibility.

SUMMARY

If used in the proper setting, serial measurements of diagnostic biomarkers may allow treatments to be adjusted at an early stage in patients with severe infections. This may involve either intensifying treatment when infection levels stay high or avoiding unnecessary prolonged courses of antibiotics when levels rapidly decrease, thereby improving the allocation of healthcare resources.

Early assessment of pancreatic infections and overall prognosis in severe acute pancreatitis by procalcitonin (PCT): a prospective international multicenter study

BACKGROUND

Pancreatic infections and sepsis are major complications in severe acute pancreatitis (AP) with significant impact on management and outcome. We investigated the value of Procalcitonin (PCT) for identifying patients at risk to develop pancreatic infections in severe AP.

METHODS

A total of 104 patients with predicted severe AP were enrolled in five European academic surgical centers within 96 hours of symptom onset. PCT was measured prospectively by a semi-automated immunoassay in each center, C-reactive protein (CRP) was routinely assessed. Both parameters were monitored over a maximum of 21 consecutive days and in weekly intervals thereafter.

RESULTS

In contrast to CRP, PCT concentrations were significantly elevated in patients with pancreatic infections and associated multiorgan dysfunction syndrome (MODS) who all required surgery (n = 10) and in nonsurvivors (n = 8) early after onset of symptoms. PCT levels revealed only a moderate increase in patients with pancreatic infections in the absence of MODS (n = 7), all of whom were managed nonoperatively without mortality. A PCT value of > or =3.5 ng/mL on 2 consecutive days was superior to CRP > or =430 mg/L for the assessment of infected necrosis with MODS or nonsurvival as determined by ROC analysis with a sensitivity and specificity of 93% and 88% for PCT and 40% and 100% for CRP, respectively (P < 0.01). The single or combined prediction of the two major complications was already possible on the third and fourth day after onset of symptoms with a sensitivity and specificity of 79% and 93% for PCT > or =3.8 ng/mL compared with 36% and 97% for CRP > or =430 mg/L, respectively (P = 0.002).

CONCLUSION

Monitoring of PCT allows early and reliable assessment of clinically relevant pancreatic infections and overall prognosis in AP. This single test parameter significantly contributes to an improved stratification of patients at risk to develop major complications.

Procalcitonin serum levels in children undergoing chronic haemodialysis

Infections account for considerable morbidity and mortality in patients requiring haemodialysis (HD). Procalcitonin (PCT)-a low molecular weight protein of 13 kDa-helps one to distinguish viral from bacterial infections and to evaluate the severity of bacterial infections. We investigated (1) PCT baseline levels in eight children undergoing chronic HD with high-flux membranes and (2) changes in the serum levels of PCT, C-reactive protein (CRP) and beta-2-microglobulin (beta2-MG)-a peptide with biochemical characteristics similar to those of PCT-before and after haemodialysis sessions. Blood sampling was performed three times in the mid-week session. Serum PCT of the seven uninfected children before HD sessions was increased (0.75+/-0.07 ng/ml), whereas CRP levels were normal. PCT after dialysis decreased significantly by 40% (P<0.0001) compared with initial values, whereas CRP levels before and after HD were not different. beta2-MG decreased by 70%, probably due to different biochemical properties of both proteins. PCT serum levels 15 min and 60 min after the HD session remained unchanged in comparison with those at the end of the HD session, suggesting accumulation of PCT between HD sessions rather than HD-induced production to be responsible for the increased baseline PCT serum levels. We concluded that CRP serum levels were not affected by HD in our group. Moderately elevated baseline PCT serum levels that are presumably due to reduced renal clearance and uraemia and dialysis-ability of PCT should be taken into consideration. However, increase of serum PCT in patients with severe bacterial infections is generally massive (10-fold to 1,000-fold), suggesting a low risk for false negative results in such cases.

[Procalcitonin measurement in adult clinical practice]

PURPOSE

The availability of a sensitive, specific and prognostic marker of bacterial infection is a major issue. More than ten years after the first publication assessing the usefulness of serum procalcitonin dosage (PCT), its exact place in the diagnostic process remained to be defined. The purpose of this review is to point out the indications of PCT measurement in clinical practice in the adult population.

RELEVANT DATA

PCT is an early, sensitive but above all specific marker of severe bacterial/parasitic infections. After being studied mostly in critically ill patients, the indications of PCT measurement have been extended to medical and emergency medicine practice, generating cut-off points between 0.2 and 0.6 microg/L. The medical area of application of PCT measurement is varied: discrimination between inflammatory disease and infectious complication or between bacterial/parasitic and viral infection, diagnosis of negative result gram staining meningitis or shock, assessment of antibiotic treatment efficiency. Moreover, PCT measurement provides outcome information in that sepsis-related raised PCT levels seem to be closely related to the magnitude of host systemic inflammatory response to microbial invasion. High PCT levels allow the early identification of patients prone to develop severe sepsis or septic shock.

PROSPECTS

After the first published study reporting the usefulness of PCT as a screening biological tool in emergency medicine, future studies will probably refined the place of PCT in such practice fields: decision about inpatient or outpatient management or antibiotics dispensation. Finally, PCT measurement could help physician in screening which septic patients should benefit from sepsis innovative therapeutics.

Procalcitonin, lipopolysaccharide-binding protein, interleukin-6 and C-reactive protein in community-acquired infections and sepsis: a prospective study

INTRODUCTION

Clinicians are in need of better diagnostic markers in diagnosing infections and sepsis. We studied the ability of procalcitonin, lipopolysaccharide-binding protein, IL-6 and C-reactive protein to identify patients with infection and sepsis.

METHODS

Plasma and serum samples were obtained on admission from patients with suspected community-acquired infections and sepsis. Procalcitonin was measured with a time-resolved amplified cryptate emission technology assay. Lipopolysaccharide-binding protein and IL-6 were measured with a chemiluminescent immunometric assay.

RESULTS

Of 194 included patients, 106 had either infection without systemic inflammatory response syndrome or sepsis. Infected patients had significantly elevated levels of procalcitonin, lipopolysaccharide-binding protein, C-reactive protein and IL-6 compared with noninfected patients (P < 0.001). In a receiver-operating characteristic curve analysis, C-reactive protein and IL-6 performed best in distinguishing between noninfected and infected patients, with an area under the curve larger than 0.82 (P < 0.05). IL-6, lipopolysaccharide-binding protein and C-reactive protein performed best in distinguishing between systemic inflammatory response syndrome and sepsis, with an area under the curve larger than 0.84 (P < 0.01). Procalcitonin performed best in distinguishing between sepsis and severe sepsis, with an area under the curve of 0.74 (P < 0.01).

CONCLUSION

C-reactive protein, IL-6 and lipopolysaccharide-binding protein appear to be superior to procalcitonin as diagnostic markers for infection and sepsis in patients admitted to a Department of Internal Medicine. Procalcitonin appears to be superior as a severity marker.

Correlation of procalcitonin and C-reactive protein to inflammation, complications, and outcome during the intensive care unit course of multiple-trauma patients

Background

A comparison of the amount of and the kinetics of induction of procalcitonin (PCT) with that of C-reactive protein (CRP) during various types of and severities of multiple trauma, and their relation to trauma-related complications, was performed.

Methods

Ninety adult trauma patients admitted to the intensive care unit of our tertiary care hospital were evaluated in a prospective case study. During the initial 24 hours after trauma the Injury Severity Score, the Sepsis-related Organ Failure Assessment score, and the Acute Physiology and Chronic Health Evaluation II score were evaluated. PCT, CRP, the sepsis criteria (American College of Chest Physicians/Society of Critical Care Medicine definitions), and the Sepsis-related Organ Failure Assessment score were measured at days 1–7, as well as at days 14 and 21, concluding the observation period with the 28-day survival.

Results

The induction of PCT and CRP varied in patients suffering from trauma. PCT increased only moderately in most patients and peaked at day 1–2 after trauma, the concentrations rapidly declining thereafter. CRP ubiquitously increased and its kinetics were much slower. Complications such as sepsis, infection, blood transfusion, prolonged intensive care unit treatment, and poor outcome were more frequent in patients with initially high PCT (>1 ng/ml), whereas increases of CRP showed no positive correlation.

Conclusion

In patients with multiple trauma due to an accident, the PCT level provides more information than the CRP level since only moderate amounts of PCT are induced, and higher concentrations correlate with more severe trauma and a higher frequency of various complications, including sepsis and infection. Most importantly, the moderate trauma-related increase of PCT and the rapidly declining concentrations provide a baseline value near to the normal range at an earlier time frame than for CRP, thus allowing a faster and more valid prediction of sepsis during the early period after trauma.

New diagnostic and prognostic markers of ventilator-associated pneumonia

PURPOSE OF REVIEW

The purpose of this review is to analyze the potential advantages and drawbacks of using biomarkers of bacterial infection for the diagnosis and prognosis of ventilator-associated pneumonia.

RECENT FINDINGS

Whereas procalcitonin and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) have both greater diagnostic accuracies than most commonly used clinical parameters and other biomarkers of infection, such as C-reactive protein, they can be increased in noninfectious conditions or remain low in patients with true infection. Furthermore, these assays cannot determine the causative organisms and associated patterns of antibiotic susceptibility.

SUMMARY

Procalcitonin and sTREM-1 should be used only as a complementary tool, to reinforce the usual diagnostic work-up. However, serial serum procalcitonin and sTREM-1 measurements may provide an opportunity to change the treatment early in the course of patients with ventilator-associated pneumonia, either to intensify treatment when their levels stay high, or to avoid unnecessary prolonged courses of antibiotics when their levels rapidly decrease. Whether procalcitonin and/or sTREM-1 guidance can reduce antibiotic use in such a setting will require additional studies, but such a strategy appears promising.

Identification and localization of procalcitonin-like immunoreactivity in the rat hypothalamus

Procalcitonin (PCT) is a 116-amino acid polypeptide physiologically produced, as the precursor protein of calcitonin (CT), in the parafollicular cells of the thyroid gland, but physiological functions and other major sources of PCT remains unclear. The distribution of PCT-like immunoreactivity (PCT-LI) in the rat hypothalamus was examined by immunohistochemistry using a monoclonal antibody raised against the mid-region of human PCT (60-77-amino acid fragment). This antibody cross-reacts well with rat PCT and immature CT, but it cross-react poorly with free mature CT. Abundant expression of PCT-LI was found in zones at the interface between brain and cerebrospinal fluid (CSF) such as the ependymal layer and ventral glia limitans (VGL). Double labeling of PCT and glial fibrillary acidic protein (GFAP) identified this population of small cells as astrocytes, possibly tanycytes, a type of specialized glial cell that interacts in neuroendocrine functional dynamics. The fibers of these cells extend to circumventricular organs (CVOs) and to astrocytes located inside the parenchyma of key autonomic regulatory hypothalamic areas, with highest densities in the supraoptic nucleus (SO), arcuate nucleus (Arc), area postrema (AP), median eminence (ME), medial preoptic nucleus, tuber cinereum, and accessory neurosecretory nuclei. No strongly labeled cells were found in the paraventricular nucleus. The wide distribution of PCT-LI in the hypothalamus, in close correspondence with previous mapping of CT receptors in the rat brain, suggests that PCT may influence a multitude of biological activities associated with the hypothalamic-pituitary axis.

Procalcitonin Guidance of Antibiotic Therapy in Community-acquired Pneumonia

RATIONALE

In patients with community-acquired pneumonia, guidelines recommend antibiotic treatment for 7 to 21 d. Procalcitonin is elevated in bacterial infections, and its dynamics have prognostic implications.

OBJECTIVE

To assess procalcitonin guidance for the initiation and duration of antibiotic therapy in community-acquired pneumonia.

METHODS

In a randomized intervention trial, 302 consecutive patients with suspected community-acquired pneumonia were included. Data were assessed at baseline, after 4, 6, and 8 d, and after 6 wk. The control group (n = 151) received antibiotics according to usual practice. In the procalcitonin group (n = 151), antibiotic treatment was based on serum procalcitonin concentrations as follows: strongly discouraged, less than 0.1 microg/L; discouraged, less than 0.25 microg/L; encouraged, greater than 0.25 microg/L; strongly encouraged, greater than 0.5 microg/L. The primary endpoint was antibiotic use; secondary endpoints were measures of clinical, laboratory, and radiographic outcome.

RESULTS

At baseline, both groups were similar regarding clinical, laboratory, and microbiology characteristics, and Pneumonia Severity Index. Procalcitonin guidance reduced total antibiotic exposure (relative risk, 0.52; 95% confidence interval, 0.48-0.55; p < 0.001), antibiotic prescriptions on admission (85 vs. 99%; p < 0.001), and antibiotic treatment duration (median, 5 vs. 12 d; p < 0.001) compared with patients treated according to guidelines. After adjustment for Pneumonia Severity Index, the hazard ratio of antibiotic discontinuation was higher in the procalcitonin group than in the control group (3.2; 95% confidence interval, 2.5 to 4.2). Outcome was similar in both groups, with an overall success rate of 83%.

CONCLUSIONS

Procalcitonin guidance substantially reduces antibiotic use in community-acquired pneumonia. These findings may have important clinical and public health implications.

Procalcitonin as a diagnostic aid in osteomyelitis and septic arthritis

OBJECTIVES

Plasma procalcitonin (PCT) increases rapidly during bacterial infections but remains low in viral infections and other inflammatory processes. High plasma PCT typically occurs in children with bacterial meningitis, severe bacterial infections, particularly in cases of septic shock or bacteremia, and in renal parenchymal damage. The aim of this study was to test the usefulness of plasma PCT analysis in the diagnosis of osteomyelitis, septic arthritis, and other skeletal inflammatory diseases in pediatric patients admitted because of fever and limping.

METHODS

White blood cell count, erythrocyte sedimentation rate, C-reactive protein, and PCT levels were measured in children admitted to the pediatric department with fever, limping, and suspected osteomyelitis or septic arthritis. PCT levels were measured by an immunochromatography assay, based on monoclonal and polyclonal antibodies against katacalcin.

RESULTS

Forty-four children were evaluated: 12 (27.3%) were diagnosed with osteomyelitis, 11 (25%) had septic arthritis, 5 children (11.4%) were diagnosed as a soft tissue infection, and transient synovitis or reactive arthritis was diagnosed in another 6 children (13.6%). Four children (9.1%) were diagnosed as having juvenile rheumatoid arthritis, and 6 (13.6%) with different diseases. PCT value was elevated in 7 patients (58.3%) with osteomyelitis, and only 3 children (27.2%) with the diagnosis of septic arthritis had a mildly elevated value. Among the children with other diagnosis, there were no positive PCT values (P < 0.001 between skeletal infection and all other diagnosis).

CONCLUSIONS

In this study, PCT was found to be a useful marker in the diagnosis of osteomyelitis and not in septic arthritis. A larger group of patients needed to be studied to confirm our findings.

Multicenter prospective study of procalcitonin as an indicator of sepsis

The clinical significance of serum procalcitonin (PCT) for discriminating between bacterial infectious disease and nonbacterial infectious disease (such as systemic inflammatory response syndrome (SIRS)), was compared with the significance of endotoxin, beta-D: -glucan, interleukin (IL)-6, and C-reactive protein (CRP) in a multicenter prospective study. The concentrations of PCT in patients with systemic bacterial infection and those with localized bacterial infection were significantly higher than the concentrations in patients with nonbacterial infection or noninfectious diseases. In addition, PCT, endotoxin, IL-6, and CRP concentrations were significantly higher in patients with bacterial infectious disease than in those with nonbacterial infectious disease (P<0.001, P<0.005, P<0.001, and P<0.001, respectively). The cutoff value of PCT for the discrimination of bacterial and nonbacterial infectious diseases was determined to be 0.5 ng/ml, which was associated with a sensitivity of 64.4% and specificity of 86.0%. Areas under the receiver operating characteristic curves (POCs) were 0.84 for PCT, 0.60 for endotoxin, 0.77 for IL-6, and 0.78 for CRP in the combined group of patients with bacterial infectious disease and those with nonbacterial infectious disease, and the area under the ROC for PCT was significantly higher than that for endotoxin (P<0.001). In patients diagnosed with bacteremia based on clinical findings, the positive rate of diagnosis with PCT was 70.2%, while that of blood culture was 42.6%. PCT is thus essential for discriminating bacterial infection from SIRS, and is superior in this respect to conventional serum markers and blood culture.

Autocrine/paracrine role of inflammation-mediated calcitonin gene-related peptide and adrenomedullin expression in human adipose tissue

Human adipose tissue is a contributor to inflammation- and sepsis-induced elevation of serum procalcitonin (ProCT). Several calcitonin (CT) peptides, including ProCT, CT gene-related peptide (CGRP), and adrenomedullin (ADM) are suspected mediators in human inflammatory diseases. Therefore, we aimed to explore the expression, interactions, and potential roles of adipocyte-derived CT peptide production. Expression of CT peptide-specific transcripts was analyzed by RT-PCR and quantitative real-time PCR in human adipose tissue biopsies and three different inflammation-challenged human adipocyte models. ProCT, CGRP, and ADM secretions were assessed by immunological methods. Adipocyte transcriptional activity, glycerol release, and insulin-mediated glucose transport were studied after exogenous CGRP and ADM exposure. With the exception of amylin, CT peptides were expressed in adipose tissue biopsies from septic patients, inflammation-activated mature explanted adipocytes, and macrophage-activated preadipocyte-derived adipocytes. ProCT and CGRP productions were significantly augmented in IL-1beta and lipopolysaccharide-challenged mesenchymal stem cell-derived adipocytes but not in undifferentiated mesenchymal stem cells. In contrast, ADM expression occurred before and after adipogenic differentiation. Interferon-gamma coadministration inhibited IL-1beta-mediated ProCT and CGRP secretion by 78 and 34%, respectively but augmented IL-1beta-mediated ADM secretion by 50%. Exogenous CGRP and ADM administration induced CT, CGRP I, and CGRP II mRNAs and dose-dependently (10(-10) and 10(-6) m) enhanced glycerol release. In contrast, no CGRP- and ADM-mediated effects were noted on ADM, TNFalpha, and IL-1beta mRNA abundances. In summary, CGRP and ADM are two differentially regulated novel adipose tissue secretion factors exerting autocrine/paracrine roles. Their lipolytic effect (glycerol release) suggests a metabolic role in adipocytes during inflammation.

Predictive value of procalcitonin for the diagnosis of bowel strangulation

Intestinal obstruction is responsible for 3% of admissions to hospital emergency surgical departments, but it is difficult to distinguish simple obstruction from strangulation. Simple criteria for this distinction are sought. In this experimental study, procalcitonin, a known marker of bacterial inflammation, was used to detect strangulation. The predictive value of procalcitonin for small bowel strangulation was evaluated. Thirty male New Zealand rabbits (mean weight: 3.0 kg) were divided into three groups. In the first (control) group, only laparatomy was performed. In the second group, simple obstruction was created by ligating a 10-cm distal ileum segment. In the third group, distal strangulation was created by ligating a 10-cm distal ileum segment with the mesentery. Blood (1 cc) was taken from the right auricular vein of each animal for measuring the procalcitonin level. In both the control group and the simple obstruction group the procalcitonin levels were normal. In the strangulation group, elevation of procalcitonin was detected after 30 minutes, and the elevation was statistically significant at 120th minute compared with the control and simple obstruction groups. In patients with small bowel obstruction, measurement of procalcitonin levels is easy to perform and can be used in the follow-up. A more extensive clinical study is needed to evaluate the accuracy of the test as a marker.

Serum Procalcitonin Levels Are Elevated in Esophageal Cancer Patients with Postoperative Infectious Complications

BACKGROUND

The normal systemic inflammatory response to surgical stimuli often makes early diagnosis of postoperative infections difficult.

PURPOSE

We investigated whether serum procalcitonin (PCT) levels may be a useful marker of bacterial infections in patients after invasive surgery.

SUBJECTS AND METHODS

The subjects were 40 patients who had undergone radical surgery for esophageal carcinoma by a right thoracoabdominal approach. Nine patients were diagnosed to have a postoperative infection during the first 7 days after surgery. Changes in serum PCT levels were compared between the group diagnosed to have postoperative infection (infection group) and the group without infection (noninfection group).

RESULTS

The postoperative serum PCT levels were significantly higher in the infection group than in the noninfection group (ANOVA: p < 0.01). Serum PCT peaked on postoperative day (POD) 5 in the infection group (8.7 +/- 8.2 ng/ml, mean +/- SD) and on POD 1 in the noninfection group (0.5 +/- 0.5 ng/ml). No significant differences were found between the two groups in leukocyte count, serum CRP or cytokine levels. The receiver operating characteristics (ROC) curve was constructed for infection identification. The area under the ROC curve for peak postoperative PCT was 0.968, and at a cutoff value of 2.0 ng/ml, the sensitivity was 89% and the specificity was 93%.

CONCLUSIONS

Serum PCT levels may be useful for the early diagnosis of postoperative infectious complications.

Prognostic value of procalcitonin in children with meningococcal sepsis

OBJECTIVE

To compare procalcitonin, lactate, and C-reactive protein as prognostic markers in children with meningococcal septic shock.

DESIGN

Prospective observational study.

SETTING

Alder Hey Children's Hospital, Liverpool, UK.

PATIENTS

Children admitted to our hospital during a 16-month period with a diagnosis of meningococcal sepsis.

RESULTS

Plasma procalcitonin at admission was significantly higher in children with septic shock (median, 73.80 vs. 16.44 ng/mL), those requiring ventilation (median, 47.02 vs. 12.00 ng/mL), and those with a duration of hospital stay >10 days (median, 131.35 vs. 19.26 ng/mL). Both procalcitonin and lactate reliably discriminated between those children with septic shock (area under the curve [AUC] = 0.85 and 0.84, respectively) and durations of hospital stay exceeding 10 days (AUC = 0.87 and 0.79, respectively) and those without, but C-reactive protein did not. Procalcitonin alone reliably discriminated between those children requiring ventilation and those who did not (AUC = 0.72).

CONCLUSION

Procalcitonin is a reliable prognostic marker of septic shock, requirement for ventilation, and prolonged hospital stay in children with meningococcal sepsis and performs better than lactate and C-reactive protein.

Expression and secretion of procalcitonin and calcitonin gene-related peptide by adherent monocytes and by macrophage-activated adipocytes

OBJECTIVE

To explore the roles of peripheral blood mononuclear cells (PBMCs) and PBMC-derived macrophages in sepsis-related increased procalcitonin and calcitonin gene-related peptide (CGRP) I production.

DESIGN

Prospective, in vitro primary human cell culture study and human tissue samples gene expression analysis.

SETTING

University hospital research laboratories.

PATIENTS

Cells from healthy donors and septic patients.

INTERVENTIONS

PBMCs were obtained from healthy donors. Isolation of pure monocyte cultures was performed by magnetic depletion of nonmonocyte cells from PBMCs. Adipose tissue biopsies and circulating leukocytes were collected from septic patients. Expressions of calcitonin messenger RNA and CGRP I messenger RNA were analyzed using reverse transcriptase-polymerase chain reaction and quantitative real-time polymerase chain reaction. Supernatant procalcitonin and CGRP protein content were determined by ultrasensitive chemiluminometric and radioimmunoassays, respectively.

MEASUREMENTS AND MAIN RESULTS

PBMCs expressed and secreted procalcitonin and CGRP within 3-5 hrs after adherence to endothelial cells or plastic surfaces. This induction was transient, as it was not detectable after 18 hrs. No calcitonin or CGRP I messenger RNA was observed in leukocytes obtained from septic patients with markedly increased serum procalcitonin concentrations. Stimulation with cytokines, endotoxin, or Escherichia coli did not induce expression of calcitonin and CGRP I messenger RNA in PBMC-derived macrophages. However, inflammatory factors released from activated macrophages induced a marked expression of procalcitonin and CGRP in co-cultured human adipocytes.

CONCLUSIONS

The adhesion-induced, transient expression and secretion of procalcitonin and CGRP in vitro may play an important role during monocyte adhesion and migration in vivo. PBMC-derived macrophages may contribute to the marked increase in circulating procalcitonin by recruiting parenchymal cells within the infected tissue, as exemplified with adipocytes.

Serum procalcitonin concentration in patients with Kawasaki disease

BACKGROUND

Procalcitonin (PCT) is a new parameter of inflammation, the clinical usefulness of which is currently being evaluated.

MATERIALS AND METHODS

We determined simultaneously the serum concentrations of PCT and C-reactive protein (CRP) as well as the white blood cell (WBC) count in 25 patients with Kawasaki disease (KD), 17 with bacterial infections, 10 with systemic autoimmune diseases, 17 with viral infections and 18 healthy children. The optimal cut-off value of each parameter for predicting coronary aneurysms was determined using receiver operating characteristic curves.

RESULTS

Significantly higher serum concentrations of PCT were observed in patients with KD (2.3 +/- 3.0 ng/ml) and bacterial infections (2.2 +/- 2.9 ng/ml) than in patients with autoimmune diseases (0.4 +/- 0.4 ng/ml) or viral infections (0.4 +/- 0.3 ng/ml), or in healthy children (0.2 +/- 0.1 ng/ml). The serum PCT but not the WBC count or CRP, differentiated the KD patients from the patients with autoimmune diseases. The optimal cut-off value of 3.0 ng/ml of PCT increased the prediction rate of coronary aneurysms that subsequently occurred in 4 (16%) patients with KD.

CONCLUSIONS

The serum PCT may be clinically useful for determining the severity of KD and for narrowing the differential diagnosis of patients with inflammatory diseases.

Procalcitonin and C-reactive protein kinetics in postoperative pediatric cardiac surgical patients

OBJECTIVE

To determine the kinetics of procalcitonin (PCT) and C-reactive protein (CRP) concentration after pediatric cardiac surgery with cardiopulmonary bypass.

DESIGN

Prospective, clinical cohort study.

SETTING

A fifteen-bed tertiary-care pediatric intensive care unit.

PATIENTS

Fourteen pediatric patients admitted for cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

Serum PCT and CRP were measured before cardiopulmonary bypass (CPB); after CPB; and on the first, second, and third days after surgery by means of immunoluminometry and nephelometry, respectively. Reference values for systemic inflammatory response syndrome are 0.5 to 2.0 ng/mL for PCT and <5 mg/L for CRP. Baseline serum PCT and CRP concentrations were 0.24 +/- 0.13 ng/mL and 4.06 +/- 3.60 mg/L (median 25th percentile-75th percentile), respectively. PCT concentrations increased progressively from the end of CPB (0.62 +/- 0.30 ng/mL), peaked at 24 hours postoperatively (POD1) (0.77 +/- 0.49 ng/mL), and began to decrease at 48 hours or POD2 (0.35 +/- 0.21 ng/mL). CRP increased just after CPB (58.82 +/- 42.23 mg/L) and decreased after 72 hours (7.09 +/- 9.81 mg/L).

CONCLUSION

An increment of both PCT and CRP was observed just after CPB. However, PCT values remained within reference values, whereas CRP concentrations increased significantly after CPB until the third day. These preliminary results suggest that PCT was more effective than CRP to monitor patients with SIRS and a favorable outcome.

Procalcitonin: improved biochemical severity stratification and postoperative monitoring in severe abdominal inflammation and sepsis

BACKGROUND

Infections and sepsis are among the most devastating complications in abdominal surgery and significantly contribute to morbidity and mortality. Early and reliable diagnosis of septic complications is notoriously difficult, and the search for novel approaches to overcome this problem is still a compelling issue for clinicians. Among a large array of inflammatory parameters, procalcitonin (PCT), the 116-amino-acid pro-peptide of calcitonin, has gained considerable importance in identifying patients at risk of developing infection and sepsis in clinical practice.

METHODS

Along with the latest insights into pathophysiological aspects of this pro-hormone, the literature as well as our own experience on the usefulness of PCT determinations in patients with severe inflammatory abdominal disorders was reviewed.

RESULTS

Although the term "sepsis" does not embrace the integral properties of PCT, a remarkable number of clinical studies have demonstrated the pivotal role of this parameter in the host response to microbial and fungal infections. In acute pancreatitis PCT allows early severity stratification and closely correlates with the development of subsequent pancreatic infections. In patients with peritonitis PCT reflects overall disease severity and is an early and reliable indicator of overall prognosis. Postoperative monitoring of PCT is a helpful tool to identify patients with evolving or persisting septic complications after elective and emergency abdominal surgery.

CONCLUSIONS

Compared with established biochemical routine variables, PCT significantly contributes to earlier and better stratification of patients at risk of developing septic complications and provides excellent prognostic assessment in severe abdominal inflammation. The currently available test systems render PCT an applicable and readily available parameter under clinical routine and emergency conditions.

In vitro and in vivo calcitonin I gene expression in parenchymal cells: a novel product of human adipose tissue

Circulating levels of calcitonin precursors (CTpr), including procalcitonin (ProCT), increase up to several thousand-fold in human sepsis, and immunoneutralization improves survival in two animal models of this disease. Herein, we analyzed inflammation-mediated calcitonin I gene (CALC I) expression in human adipocyte primary cultures and in adipose tissue samples from infected and noninfected patients with different levels of serum ProCT. In ex vivo differentiated adipocytes, the expression of CT mRNA increased 24-fold (P < 0.05) after the administration of Escherichia coli endotoxin (lipopolysaccharide) and 37-fold (P < 0.05) after IL-1beta administration by 6 h. ProCT protein secretion into culture supernatant increased 13.5-fold (P < 0.01) with lipopolysaccharide treatment and 15.2-fold (P < 0.01) with IL-1beta after 48 h. In coculture experiments, adipocyte CT mRNA expression was evoked by E. coli-activated macrophages in which CT mRNA was undetectable. The marked IL-1beta-mediated ProCT release was inhibited by 89% during coadministration with interferon-gamma (IFNgamma). In patients with infection and markedly increased serum ProCT, CT mRNA was detected in adipose tissue biopsies. Hence, we demonstrate that ProCT, which is suspected to mediate deleterious effects in sepsis and inflammation, is a novel product of adipose tissue secretion. The inhibiting effect of IFNgamma on IL-1beta-induced CT mRNA expression and on ProCT secretion might explain previous observations that serum ProCT concentrations increase less in systemic viral compared with bacterial infections.

Measurements in the intensive care unit: what do they mean?

Intensivists depend upon a large number of measurements to make daily decisions in the ICU. However, the reliability of these measures may be jeopardized by the effects of therapy. Moreover, in critical illness, what is normal is not necessarily optimal. Procalcitonin, a putative marker of occult infection, is emerging as a valuable diagnostic marker in the ICU. Although questions remain regarding its specificity, an increasing body of work suggests that it is reliably elevated in the setting of infection. As demonstrated by Level and colleagues in this issue of Critical Care, its utility as a diagnostic marker is not affected by concomitant hemodialysis.

Mass transfer, clearance and plasma concentration of procalcitonin during continuous venovenous hemofiltration in patients with septic shock and acute oliguric renal failure

Objectives

To measure the mass transfer and clearance of procalcitonin (PCT) in patients with septic shock during continuous venovenous hemofiltration (CVVH), and to assess the mechanisms of elimination of PCT.

Setting

The medical department of intensive care.

Design

A prospective, observational study.

Patients

Thirteen critically ill patients with septic shock and oliguric acute renal failure requiring continuous venovenous postdilution hemofiltration with a high-flux membrane (AN69 or polyamide) and a 'conventional' substitution volume (< 2.5 l/hour).

Measurements and main results

PCT was measured with the Lumitest PCT Brahms^® in the prefilter and postfilter plasma, in the ultrafiltrate at the beginning of CVVH (T0) and 15 min (T15'), 60 min (T60') and 6 hours (T6h) after setup of CVVH, and in the prefilter every 24 hours during 4 days. Mass transfer was determined and the clearance and the sieving coefficient were calculated according to the mass conservation principle. Plasma and ultrafiltrate clearances, respectively, at T15', T60' and T6h were 37 ± 8.6 ml/min (not significant) and 1.8 ± 1.7 ml/min (P < 0.01), 34.7 ± 4.1 ml/min (not significant) and 2.3 ± 1.8 ml/min (P < 0.01), and 31.5 ± 7 ml/min (not significant) and 5 ± 2.3 ml/min (P < 0.01). The sieving coefficient significantly increased from 0.07 at T15' to 0.19 at T6h, with no difference according to the nature of the membrane. PCT plasma levels were not significantly modified during the course of CCVH.

Conclusions

We conclude that PCT is removed from the plasma of patients with septic shock during CCVH. Most of the mass is eliminated by convective flow, but adsorption also contributes to elimination during the first hours of CVVH. The effect of PCT removal with a conventional CVVH substitution fluid rate (<2.5 l/hour) on PCT plasma concentration seems to be limited, and PCT remains a useful diagnostic marker in these septic patients. The impact of high-volume hemofiltration on the PCT clearance, the mass transfer and the plasma concentration should be evaluated in further studies.

Calcitonin precursors: early markers of gut barrier dysfunction in patients with acute pancreatitis

BACKGROUND

Severe acute pancreatitis is associated with an early increase in intestinal permeability and endotoxemia. Endotoxin is a potent stimulator for the production and release of procalcitonin and its components (calcitonin precursors; [CTpr]). The aim of this study is to evaluate the role of plasma CTpr as an early marker for gut barrier dysfunction in patients with acute pancreatitis.

METHODS

Intestinal permeability to macromolecules (polyethylene glycol 3350), serum endotoxin and antiendotoxin core antibodies, plasma CTpr, and serum C-reactive protein (CRP) were measured on admission in 60 patients with acute pancreatitis. Attacks were classified as mild (n = 48) or severe (n = 12) according to the Atlanta criteria.

RESULTS

Compared with mild attacks of acute pancreatitis, severe attacks were significantly associated with an increase in intestinal permeability index (median: 0.02 vs. 0.006, P < 0.001), the frequency of endotoxemia (73% vs. 41%, P = 0.04), and the extent of depletion of serum IgM antiendotoxin antibodies (median: 43 MMU vs. 100 MMU, P = 0.004). Plasma CTpr levels were significantly elevated in patients with severe attacks compared with mild attacks on both the day of admission and on day 3 (median: 64 vs. 22 fmol/mL, P = 0.03; and 90 vs. 29 fmol/mL, P = 0.003 respectively). A positive and significant correlation was observed between the admission serum endotoxin and plasma CTpr levels on admission (r = 0.7, P < 0.0001) and on day 3 (r = 0.96, P < 0.0001), and between plasma CTpr on day 7 and the intestinal permeability index (r = 0.85, P = 0.0001). In contrast, only a weak positive correlation was observed between peak serum levels of CRP and plasma CTpr on admission (r = 0.3, P = 0.017) and on day 7 (r = 0.471, P = 0.049), as well as between CRP and each of the admission serum endotoxin (r = 0.3, P = 0.03) and the intestinal permeability index (r = 0.375, P = 0.007).

CONCLUSIONS

In patients with acute pancreatitis, plasma concentrations of CTpr appear to reflect more closely the derangement in gut barrier function rather than the extent of systemic inflammation.

Calcitonin gene related peptide and N-procalcitonin modulate CD11b upregulation in lipopolysaccharide activated monocytes and neutrophils

OBJECTIVE

Circulating levels of calcitonin gene related peptide (CGRP) and calcitonin precursors, including procalcitonin (PCT) and its free aminopeptide N-procalcitonin (N-PCT), have been found dramatically increased in septic patients. PCT is known to attenuate the chemotaxis of monocytes in response to chemoattractants. This study examined whether CGRP and N-PCT modulate the LPS-induced expression of CD11b, which is one of the major integrins involved in monocyte and neutrophil chemotaxis during a response to microbial infections.

DESIGN AND SETTING

In vitro cell culture study in the immunology laboratory of a university hospital.

PARTICIPANTS

Healthy volunteers.

MEASUREMENTS AND RESULTS

We assessed the effects of N-PCT and CGRP on CD11b expression on monocytes and neutrophils after LPS (2 ng/ml) or fMLP (10(-8) M) challenges. We used a human whole blood model, and measurements were made by flow cytometry. Both peptides in a dose-dependent manner decreased the LPS- and fMLP-induced rise in CD11b in monocytes and neutrophils. As these peptides are thought to act by raising cAMP, we also mimicked their effects with the use of rolipram and forskolin and found similar results.

CONCLUSIONS

These findings are in line with recent studies demonstrating anti-inflammatory properties for this family of peptides. CGRP and calcitonin precursors may function as factors suppressing the propagation of inflammation through the inhibition of several processes involved during a response to a bacterial stimulus.

Hepatic ischemia-reperfusion syndrome after partial liver resection (LR): hepatic venous oxygen saturation, enzyme pattern, reduced and oxidized glutathione, procalcitonin and interleukin-6

The hepatic ischemia-reperfusion syndrome was investigated in 28 patients undergoing elective partial liver resection with intraoperative occlusion of hepatic inflow (Pringle maneuver) using the technique of liver vein catheterization. Hepatic venous oxygen saturation (ShvO2) was monitored continuously up to 24 hours after surgery. Aspartate aminotransferase, glutamate dehydrogenase, gamma-glutamyl transpeptidase, pseudocholinesterase, alpha-glutathione S-transferase, reduced and oxidized glutathione, procalcitonine, and interleukin-6 were serially measured both before and after Pringle maneuver during the resection and postoperatively in arterial and/or hepatic venous blood. ShvO2 measurement demonstrated that peri- and postoperative management was suitable to maintain an optimal hepatic oxygen supply. As expected, we were able to demonstrate a typical enzyme pattern of postischemic liver injury. There was a distinct decrease of reduced glutathione levels both in arterial and hepatic venous plasma after LR accompanied by a strong increase in oxidized glutathione concentration during the phase of reperfusion. We observed increases in procalcitonin and interleukin-6 levels both in arterial and hepatic venous blood after declamping. Our data support the view that liver resection in man under conditions of inflow occlusion resulted in ischemic lesion of the liver (loss of glutathione synthesizing capacity with disturbance of protection against oxidative stress) and an additional impairment during reperfusion (liberation of reactive oxygen species, local and systemic inflammation reaction with cytokine production). Additionally, we found some evidence for the assumption that the liver has an export function for reduced glutathione into plasma in man.

Prophylactic N-acetylcysteine decreases serum CRP but not PCT levels and microalbuminuria following major abdominal surgery. A prospective, randomised, double-blinded, placebo-controlled clinical trial

OBJECTIVE

Our objective was to investigate whether short-term infusion of the oxygen free radical scavenger N-acetylcysteine (NAC) administered before and during extensive abdominal surgery could ameliorate the progression of early systemic inflammatory response.

DESIGN

Prospective, randomised, double-blinded, placebo-controlled clinical trial.

SETTING

Twenty-bed intensive care unit in a university hospital.

PATIENTS

Following written informed consent, 100 patients were randomised into NAC and placebo groups. Three patients from the NAC group and four from the placebo group withdrew before the final analysis.

INTERVENTION

The treatment group (n=47) received NAC (150 mg/kg(-1) bolus followed by a continuous infusion of 12 mg/kg(-1)/h(-1)) and the placebo group ( n=46) received the same volume of 5% dextrose during surgery.

MEASUREMENTS AND RESULTS

Serum procalcitonin (PCT), C-reactive protein (CRP) and microalbuminuria was monitored preoperatively, on admission to ICU, then daily during the first 3 postoperative days. For statistical analysis Mann Whitney and Chi-squared tests were used. Patients' clinical course was similar in each group as monitored by the Multiple Organ Dysfunction Scores. There was no significant difference between the two groups regarding PCT and microalbuminuria at any assessment point. Significantly lower CRP levels were found in the NAC group on days 1 and 2 (t(24): median: 84.5 interquartile range: [62-120] vs. 118 [86-137] mg/l; p=0.020; t(48): 136 [103-232] vs. 195 [154-252] mg/l; p=0.013, NAC vs. placebo respectively).

CONCLUSION

In this study, short-term NAC treatment decreased CRP levels, but failed to attenuate any other inflammatory response, as monitored by serum PCT and microalbuminuria. Overall, our results do not support the routine prophylactic use of NAC as a free radical scavenger in abdominal surgery.

Late immunoneutralization of procalcitonin arrests the progression of lethal porcine sepsis

BACKGROUND

Procalcitonin (ProCT) is becoming increasingly recognized as a mediator as well as a marker of sepsis. Serum ProCT concentrations rise soon after induction of sepsis and remain elevated over a prolonged period of time. In contrast, many pro-inflammatory cytokines, e.g., tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1beta), rise and decline early in the course of sepsis. Researchers have improved survival in animal models of sepsis by prophylactically blocking IL-1beta and TNF-alpha with immunotherapy, but therapeutic treatment has been less successful in clinical trials. We hypothesized that the sustained elevation of ProCT in the serum would allow for effective therapeutic immunoneutralization of this peptide late in the course of sepsis.

METHODS

Lethal polymicrobial sepsis was induced in 10 castrated, male Yorkshire pigs by intraabdominal spillage of cecal contents (1 gm/kg) and intraabdominal instillation of 2 x 10(11) cfu of a toxigenic strain of E. coli (O18:K1:H7). The treated group (n = 5) received an intravenous infusion of purified rabbit antiserum to the aminoterminus of porcine ProCT. The control group (n = 5) received nonreactive, purified rabbit IgG. The purified antiserum was infused to all animals 3 h after the induction of sepsis, at which time very severe physiologic dysfunction was manifest, and many of the animals appeared to be preterminal. Physiologic and metabolic parameters were measured until death or for 15 h after induction of sepsis, at which time all surviving animals were euthanized.

RESULTS

Therapeutic immunoneutralization of serum ProCT improved most measured physiologic and metabolic parameters in septic pigs. Specifically, there was a significant increase in mean arterial pressure, urine output and cardiac index in all animals treated with ProCT antibody. Serum creatinine was significantly lower in treated animals. Although acidosis was not as severe in treated animals, as indicated by higher pH values and lower lactate concentrations, these results did not achieve statistical significance. Significantly, 11 h after the induction of sepsis there was 100% mortality in the control group while only one animal in the treated group expired.

CONCLUSION

The prolonged elevation of ProCT concentrations in sepsis allows neutralization of this peptide to be effective during the course of this disorder. These findings suggest that immunoneutralization of ProCT may be a useful treatment in clinical situations where sepsis is already fully established.

Procalcitonin and C-reactive protein plasma concentrations in nonseptic uremic patients undergoing hemodialysis

OBJECTIVE

To assess procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations and clearance in nonseptic end-stage renal failure patients undergoing their first three hemodialysis sessions.

DESIGN AND SETTING

Prospective observational consecutive clinical study at a university hospital.

PATIENTS

The study recruited 55 end-stage renal failure patients without evidence of systemic infection undergoing the creation of an arteriovenous fistula to start hemodialysis for the first time.

INTERVENTIONS

Blood samples were collected before and after each of the first three (4-5 h) hemodialysis sessions. PCT was assayed by immunoluminometry.

MEASUREMENTS AND RESULTS

The mean plasma concentration of PCT prior to the first three hemodialysis sessions declined significantly following each session. There was no significant difference between CRP plasma concentrations before and after hemodialysis sessions.

CONCLUSIONS

The presence of an elevated PCT in plasma of not yet dialyzed uremic nonseptic patients indicates that uremia per se and not the dialysis process is the origin of such elevation. PCT levels declined with successive hemodialysis sessions. We propose that in the not yet dialyzed uremic nonseptic patients a baseline PCT level of approx. 1.5 ng/ml should be expected. Although the mean plasma CRP level was elevated, hemodialysis had no significant effect on CRP concentration, making CRP a possible useful marker of sepsis in these patients.