In vitro modulation of inducible nitric oxide synthase gene expression and nitric oxide synthesis by procalcitonin

Predicting long-term cardiovascular outcomes in myocardial infarction survivors using multiple biomarkers

Aim: Although there are short- and long-term prognostic studies in patients with myocardial infarction (MI), the data that can be used to predict the clinical outcome following discharge is limited. Materials & methods: We analyzed creatinine kinase-MB and troponin related to myonecrosis, suppression of tumorigenicity 2 and NT-pro B-type natriuretic peptide related to myocardial stress, C-reactive protein and procalcitonin related to inflammation in 259 MI patients. Results: Being in the high group for myocardial stress (odds ratio [OR]: 3.45, 95% CI: 1.398-8.547, p = 0.004) and inflammation markers (OR: 4.30, 95% CI: 1.690-10.899, p = 0.001) predicted major cardiovascular adverse events while myonecrosis markers could not (OR: 1.70, 95% CI: 0.671-4.306, p = 0.263). Conclusion: Using multimarker risk stratification composed of inflammation and myocardial stress biomarkers improves the prediction of major cardiovascular adverse events in MI survivors.

Procalcitonin expression in patients with large cell neuroendocrine carcinoma of the lung

Objective

Procalcitonin (PCT) has received much attention as a serum marker for bacterial infection. Elevated serum PCT is occasionally seen in severe trauma, heatstroke, and neoplastic diseases, including lung cancer with neuroendocrine component.

Results

In the present study, we evaluated PCT expression in the specimen of pulmonary neuroendocrine tumors, comparing large cell neuroendocrine carcinoma (LCNEC), carcinoid, and small cell lung carcinoma (SCLC). Pathological specimens of 10 LCNEC, 4 carcinoid, and 7 SCLC cases were evaluated with immunochemical staining of PCT. Clinical characteristics and serum levels of PCT and C-reactive protein were also evaluated. We observed positive PCT expression in 5 (50%) LCNEC and 2 (50%) carcinoid specimens that were surgically resected. Whereas serum PCT levels were not elevated in patients with PCT-positive carcinoid, two out of three LCNEC patients with high PCT expression in the tumor had elevated serum PCT levels that reflected disease progression. In patients with SCLC, PCT was not detected in the tumor or serum. This is the first immunohistochemical study of the PCT expression in the lung tumor specimens. We concluded that, in patients with LCNEC, high serum PCT levels may be indicative of disease activity and serve as a biomarker.

Biomarker Guided Diagnosis of Septic Peritonitis in Dogs

Septic peritonitis (SP) is common in dogs and is associated with high mortality. Early recognition is essential to maximizing survival and may be aided by biomarker measurement. The present study aimed to evaluate the ability of biomarkers to discriminate septic peritonitis from non-septic ascites (NSA). Eighteen dogs with SP and 19 age-matched controls with NSA were enrolled. Contemporaneous blood and peritoneal effusion samples were obtained. Concentrations of cell-free DNA (cfDNA), cytokines, glucose, lactate, N-terminal pro-C-type natriuretic peptide (NT-proCNP), nucleosomes, and procalcitonin (PCT) were measured using commercial reagents and assays. Paired biomarker concentrations were compared with the Wilcoxon matched-pairs signed rank test, and biomarker concentrations between groups were compared with the Mann-Whitney U-test. P-values were adjusted for multiple comparisons using the Bonferroni correction. Receiver operating characteristic curves were generated to assess the ability of the above biomarkers to discriminate SP from NSA. Dogs with SP had significantly greater blood CCL2 concentrations than dogs with NSA (P = 0.032). Dogs with SP had significantly greater effusion CCL2, IL-6, IL-10, and lactate concentrations than dogs with NSA (P ≤ 0.0121). Blood-effusion concentration gradients of CCL2, glucose, IL-6, IL-10, and lactate were significantly different in dogs with SP compared to dogs with NSA (P ≤ 0.0165). Effusion lactate concentration had the highest AUROC value (0.866, 95% CI 0.751–0.980, P = 0.0001), although other biomarkers performed similarly. An effusion lactate concentration of 4.2 mmol/L was 72.2% (95% CI 46.5–90.3%) sensitive and 84.2% (95% CI 60.4–96.6%) specific for the diagnosis of SP.

Plasma procalcitonin concentrations are increased in dogs with sepsis

Sepsis, the life-threatening organ dysfunction caused by a dysregulated host response to infection, is difficult to identify and to prognosticate for. In people with sepsis, procalcitonin (PCT) measurement aids diagnosis, enables therapeutic monitoring and improves prognostic accuracy. This study used a commercial canine PCT assay to measure plasma PCT concentrations in dogs with gastric dilatation volvulus (GDV) syndrome and in dogs with sepsis. It was hypothesised that dogs with GDV syndrome and with sepsis have greater plasma PCT concentrations than healthy dogs and that dogs with sepsis have greater PCT concentrations than dogs with GDV syndrome. Before analysing canine plasma samples, the ability of the assay to identify canine PCT, in addition to assay imprecision and the lower limit of detection were established. The assay had low imprecision with coefficients of variation ≤4.5 per cent. The lower limit of detection was 3.4 pg/ml. Plasma PCT concentrations were measured in 20 dogs with sepsis, in 32 dogs with GDV syndrome and in 52 healthy dogs. Median (IQR) PCT concentration in dogs with sepsis 78.7 pg/ml (39.1-164.7) was significantly greater than in healthy dogs 49.8 pg/ml (36.2-63.7) (P=0.019), but there were no significant differences between PCT concentrations in dogs with GDV syndrome and controls (P=0.072) or between dogs with sepsis and GDV syndrome (P=1.000). Dogs with sepsis have significantly increased plasma PCT concentrations compared with healthy dogs, although considerable overlap between these populations was identified. Future investigations should confirm this finding in other populations and evaluate the diagnostic and prognostic value of PCT in dogs with sepsis.

Procalcitonin Levels in Survivors and Nonsurvivors of Sepsis: Systematic Review and Meta-Analysis

Procalcitonin (PCT) is an acute-phase reactant that has been used to diagnose and potentially track the treatment of sepsis. Procalcitonin values rise initially as the infection sets in and eventually fall with resolution. Its level has been reported to be significantly higher in potential nonsurvivors of a septic episode than among survivors. However, there is also a significant amount of evidence against this. We thus conducted a meta-analysis to pool data from all the available studies regarding PCT levels in survivors and nonsurvivors of sepsis. An extensive literature search was conducted using the key words "procalcitonin," "sepsis," and "prognosis." The references of the relevant studies were also scanned. The data from the eligible studies were extracted and analyzed for any significant pooled mean difference between survivors and nonsurvivors both on days 1 and 3. The mean difference in the day 1 PCT values between survivors and nonsurvivors was found to be statistically significant (P = 0.02). The mean difference on day 3 was also statistically significant (P = 0.002). However, in a subgroup consisting of studies on patients with severe sepsis and septic shock, day 1 difference was not found to be significant (P = 0.62). We found heterogeneity of 90% in our study population, which decreased to 62% after exclusion of studies conducted in emergency department patients. Procalcitonin levels in early stages of sepsis are significantly lower among survivors as compared with nonsurvivors of sepsis.

Serum value of procalcitonin as a marker of intestinal damages: type, extension, and prognosis

BACKGROUND

Ischemic and necrotic damages are complications of digestive diseases and require emergency management. Nevertheless, the decision to surgically manage could be delayed because of no sufficiently preoperative accurate marker of ischemia diagnosis, extension, and prognosis.

METHODS

The aim of this study was to assess the predictive value of serum procalcitonin (PCT) levels for diagnosing intestinal necrotic damages, their extension, and their prognosis in patients with ischemic disease including ischemic colitis and mesenteric infarction by a gray zone approach. Between January 2007 to June 2014, 128 patients with ischemic colitis and mesenteric infarction (codes K55.0 and K51.9) were operated, for whom data on PCT were available. We perform a retrospective, multicenter review of their medical records. Patients were divided into subgroups: ischemia (ID group) versus necrosis (ND group); the extension [focal (FD) vs. extended (ED)] and the vital status [deceased (D) vs. alive (A)].

RESULTS

PCT levels were higher in the ND (n = 94; p = 0.009); ED (n = 100; p = 0.02); and D (n = 70; p = 0.0003) groups. With a gray zone approach, the predictive thresholds were (i) for necrosis 2.473 ng/mL, (ii) for extension 3.884 ng/mL, and (iii) for mortality 7.87 ng/mL.

CONCLUSION

In our population, PCT could be used as a marker of necrosis; especially in case of extended damages and reflects the patient's prognosis.

Update on procalcitonin measurements

Procalcitonin (PCT) is used as a biomarker for the diagnosis of sepsis, severe sepsis and septic shock. At the same time, PCT has also been used to guide antibiotic therapy. This review outlines the main indications for PCT measurement and points out possible pitfalls. The classic indications for PCT measurement are: (i) confirmation or exclusion of diagnosis of sepsis, severe sepsis, or septic shock, (ii) severity assessment and follow up of systemic inflammation mainly induced by microbial infection, and (iii) individual, patient adapted guide of antibiotic therapy and focus treatment. Using serially monitored PCT levels, the duration and need of antibiotic therapy can be better adapted to the individual requirements of the patient. This individualized approach has been evaluated in various studies, and it is recommended to be a part of an antibiotic stewardship program.

Procalcitonin as a prognostic biomarker of severe sepsis and septic shock

OBJECTIVE

To evaluate the tendency of the plasma concentration and clearance of procalcitonin (PCT-c) as biomarkers of prognosis of patients with severe sepsis and septic shock, compared to another early prognosis marker, the number of SIRS criteria at sepsis diagnosis.

METHODS

We conducted a prospective, observational, cohort study, with patients with severe sepsis and septic shock. The serum procalcitonin was determined at diagnosis of sepsis and after 24 and 48 hours. Demographic data, APACHE IV, SOFA score on arrival, number of SIRS criteria at diagnosis, site of infection and microbiological results were recorded.

RESULTS

Twenty-eight patients were included, 19 clinical and nine surgical. In 13 (46.4%) the source of sepsis was pulmonary, abdominal in seven (25.0%), urinary in five (17.9%) and soft tissue in three cases (10.7%). Fifteen patients had severe sepsis and 13 septic shock. Overall mortality was 17.9% (five patients), three with septic shock. Twenty-eight PCT determinations were performed at sepsis diagnosis, 27 after 24 hours and 26 after 48 hours. The initial concentration was not significantly different between survivors and non-survivors groups, but the differences between the two groups after 24 and 48 hours were statistically significant. There was no difference in the number of SIRS criteria. The 24-hour procalcitonin clearance proved to be significantly higher in the group of survivors (-3.0 versus -300.0, p = 0.028). Although the 48-hour procalcitonin clearance has shown to be higher in the group of survivors when compared to non-survivors, the difference did not reach statistical significance.

CONCLUSION

Persistently high procalcitonin concentrations in plasma, as well as reduced 24-hours PCT clearence, were associated with a significant increase in mortality in patients with severe sepsis and septic shock.

Procalcitonin as a biomarker of acute lower respiratory tract infections

BACKGROUND

Procalcitonin (PCT) has emerged as a promising 'acute phase' biomarker used for diagnosis of acute bacterial infections of the respiratory tract. The introduction of new sensitive PCT assays has facilitated implementation of a new clinical approach to reduce antibiotic use in acute lower respiratory tract infections (LRTIs), without compromising patient safety.

OBJECTIVE

Current state of knowledge on the clinical usefulness of serum PCT measurements for the evaluation of acute LRTIs is presented herein, together with basic information on available rapid diagnostic tests for PCT measurement.

METHODS

During the literature search the emphasis was on PCT use as a diagnostic, monitoring and prognostic tool for acute LRTIs. The acute LRTIs have been defined as acute bronchitis, acute exacerbations of chronic obstructive pulmonary disease or asthma, and pneumonia. Original studies involving patients with these conditions have been considered, and recent articles documenting interventional trials on PCT use for guidance of antimicrobial treatment in LRTIs have been reviewed in particular.

RESULTS/CONCLUSION

When measured with sensitive and rapid assays, PCT has proved to be a good biomarker for acute bacterial LRTIs, which enables an early diagnosis, facilitates therapeutic decisions, and can inform clinicians about the course of disease and prognosis. PCT can become a particularly suitable tool for implementation in an emergency and acute medical care setting.

New approaches to sepsis: molecular diagnostics and biomarkers

Sepsis is among the most common causes of death in hospitals. It arises from the host response to infection. Currently, diagnosis relies on nonspecific physiological criteria and culture-based pathogen detection. This results in diagnostic uncertainty, therapeutic delays, the mis- and overuse of antibiotics, and the failure to identify patients who might benefit from immunomodulatory therapies. There is a need for new sepsis biomarkers that can aid in therapeutic decision making and add information about screening, diagnosis, risk stratification, and monitoring of the response to therapy. The host response involves hundreds of mediators and single molecules, many of which have been proposed as biomarkers. It is, however, unlikely that one single biomarker is able to satisfy all the needs and expectations for sepsis research and management. Among biomarkers that are measurable by assays approved for clinical use, procalcitonin (PCT) has shown some usefulness as an infection marker and for antibiotic stewardship. Other possible new approaches consist of molecular strategies to improve pathogen detection and molecular diagnostics and prognostics based on transcriptomic, proteomic, or metabolic profiling. Novel approaches to sepsis promise to transform sepsis from a physiologic syndrome into a group of distinct biochemical disorders and help in the development of better diagnostic tools and effective adjunctive sepsis therapies.

The effect of telemedicine in critically ill patients: systematic review and meta-analysis

INTRODUCTION

Telemedicine extends intensivists' reach to critically ill patients cared for by other physicians. Our objective was to evaluate the impact of telemedicine on patients' outcomes.

METHODS

We searched electronic databases through April 2012, bibliographies of included trials, and indexes and conference proceedings in two journals (2001 to 2012). We selected controlled trials or observational studies of critically ill adults or children, examining the effects of telemedicine on mortality. Two authors independently selected studies and extracted data on outcomes (mortality and length of stay in the intensive care unit (ICU) and hospital) and methodologic quality. We used random-effects meta-analytic models unadjusted for case mix or cluster effects and quantified between-study heterogeneity by using I² (the percentage of total variability across studies attributable to heterogeneity rather than to chance).

RESULTS

Of 865 citations, 11 observational studies met selection criteria. Overall quality was moderate (mean score on Newcastle-Ottawa scale, 5.1/9; range, 3 to 9). Meta-analyses showed that telemedicine, compared with standard care, is associated with lower ICU mortality (risk ratio (RR) 0.79; 95% confidence interval (CI), 0.65 to 0.96; nine studies, n = 23,526; I2 = 70%) and hospital mortality (RR, 0.83; 95% CI, 0.73 to 0.94; nine studies, n = 47,943; I² = 72%). Interventions with continuous patient-data monitoring, with or without alerts, reduced ICU mortality (RR, 0.78; 95% CI, 0.64 to 0.95; six studies, n = 21,384; I² = 74%) versus those with remote intensivist consultation only (RR, 0.64; 95% CI, 0.20 to 2.07; three studies, n = 2,142; I2 = 71%), but effects were statistically similar (interaction P = 0.74). Effects were also similar in higher (RR, 0.83; 95% CI, 0.68 to 1.02) versus lower (RR, 0.69; 95% CI, 0.40 to 1.19; interaction, P = 0.53) quality studies. Reductions in ICU and hospital length of stay were statistically significant (weighted mean difference (telemedicine-control), -0.62 days; 95% CI, -1.21 to -0.04 days and -1.26 days; 95% CI, -2.49 to -0.03 days, respectively; I2 > 90% for both).

CONCLUSIONS

Telemedicine was associated with lower ICU and hospital mortality among critically ill patients, although effects varied among studies and may be overestimated in nonrandomized designs. The optimal telemedicine technology configuration and dose tailored to ICU organization and case mix remain unclear.

Immune regulation of procalcitonin: a biomarker and mediator of infection

Procalcitonin (PCT) has recently emerged as a powerful biomarker for an early and accurate diagnosis of bacterial infection. Here we summarize our current understanding of the expression pathways of PCT, its potential cellular sources including immune cells, and factors inducing its secretion. Also addressed is the significance of increased blood PCT concentration, which may allow this molecule not only to act as a clinical biomarker but also as an active participant in the development and progression of infectious processes. Experimental approaches to delineate a better understanding of PCT functions, molecular pathways that modulate its expression and therapeutic opportunities to curtail its biological actions are discussed, as well.

Biomarkers in the critically ill patient: procalcitonin

Infection and/or sepsis biomarkers should help to make the diagnosis and thus initiate therapy earlier, help to differentiate between infectious and sterile inflammation, allow the use of more-specific antimicrobials, shorten the time of antimicrobial use, and ideally identify distinct phenotypes that may benefit from specific adjunctive sepsis therapies. Procalcitonin (PCT) was proposed as a sepsis and infection marker more than 15 years ago. Meanwhile, PCT has been evaluated in various clinical settings. In this review the present use of PCT on the ICU and in critically ill patients is summarized, included it's role for diagnosis of severe sepsis and septic shock and antibiotic stewardship with PCT.

Serum concentrations of procalcitonin after cardiac surgery

BACKGROUND AND AIM

Monitoring of complications in patients undergoing cardiac surgery may be difficult because cardiopulmonary bypass (CPB) can lead to a systemic inflammatory response syndrome because of exposure of blood to nonphysiological surfaces. The purpose of the study was to establish the baseline levels of procalcitonin (PCT) after cardiac surgery in our population in order to analyze a possible induction of the inflammatory response that might interfere with the diagnosis of infection by PCT.

METHODS

Serum samples from patients undergoing coronary artery bypass grafting or valve replacement were collected at the time of admission to intensive care unit, after surgery as well as in the first and second postoperative days. Patients were followed for the development of postoperative complications. PCT levels were measured by immunoluminometric assay.

RESULTS

The mean PCT values were significantly higher in the first postoperative day in all the groups except the control group. No increased PCT levels were found related neither to duration of CPB, nor to time of aortic clamping. Only patients who presented complications had significantly increased PCT values immediately after surgery (p = 0.004), in the first postoperative day (p < 0.0001), and in the second postoperative day (p < 0.0001) with respect to those who recovered uneventfully.

CONCLUSIONS

A slight and transient increase in PCT levels was observed in the first postoperative day after cardiac surgery. Significant elevation of PCT was only observed when complications were present.

Procalcitonin implication in renal cell apoptosis induced by acute pyelonephritis in children

The aim of this biomedical trial was to clarify the physiological role of procalcitonin (PCT) in renal parenchyma apoptosis and fibrosis caused by acute childhood pyelonephritis. This prospective study enrolled 183 children. All children were treated with bi-therapy according to the French consensus on acute pyelonephritis treatment dated November 16, 1990: intra-vascular administration of ceftriaxone 50 mg/kg/day and netromicine 7 mg/kg/day during the first 48 hours, followed by specific antibiotherapy suited to antibiogram. On admission, PCT, C-reactive protein, and phospholipase A2 were quantified in serum. Scintigraphy monitoring with ^99mTc-DMSA was performed on day 4 and 9 months later, in the presence of persistent abnormalities. On day 4, 78% presented renal parenchyma alterations and 30% renal fibrosis 9 months after admission. Paradoxically, PCT level was significantly lower in the presence of renal fibrosis due to cell apoptosis (4.19 vs 7.59 μgL⁻¹). A significant increase in PCT indicated favorable progress (recovery 7.55 vs aggravation 3.34) and no difference between recovery and improvement. This result suggests the protective effect of PCT against apoptosis by nitric oxide down-regulation.

Examination of the effect of procalcitonin on human leucocytes and the porcine isolated coronary artery

BACKGROUND

The aim of this study was to investigate the effects of procalcitonin on the lipopolysaccharide (LPS)-induced changes in human leucocytes and porcine isolated coronary artery.

METHODS

Using flow cytometry, changes in forward scatter and intracellular calcium in human neutrophils and monocytes were determined after exposure to procalcitonin, calcitonin gene-related peptide (CGRP), LPS, and the known chemoattractants formylated methionine-leucine-phenylalanine (fMLP) and interleukin-8 (IL-8). In porcine isolated coronary artery, the effects of procalcitonin were evaluated using the contractile function change and the release of TNFalpha.

RESULTS

In human neutrophils and monocytes, procalcitonin (100 nM), but not CGRP, increased forward scatter and the expression of surface markers (CD16 and CD14, respectively) in a similar manner to 10 microg ml(-1) LPS. Procalcitonin, but not CGRP, also increased the proportion of cells exhibiting an increase in intracellular calcium ions similar to that produced by fMLP and IL-8. Acute exposure of the coronary artery to procalcitonin produced a small, endothelium-independent relaxation (approximately 15% of constrictor tone), but failed to modify subsequent relaxations to CGRP. After 16 h exposure, procalcitonin (100 nM) increased TNFalpha release from the coronary artery equivalent to 70% of that produced by LPS, but did not modify the inhibitory effect of LPS (100 microg ml(-1)) on contractile responses.

CONCLUSIONS

Procalcitonin has a proinflammatory effect on human leucocytes and porcine coronary artery, but it is not capable of modulating LPS-induced changes in vascular responsiveness in vitro.

Biomarkers of sepsis: clinically useful?

PURPOSE OF REVIEW

The purpose of this review is to indicate recent developments in biomarkers of sepsis and to evaluate their impact on clinical use. According to the 'surviving sepsis campaign,' diagnosis of sepsis and infection is urgent; early and specific treatment is most effective to reduce complications and to decrease mortality.

RECENT FINDINGS

A variety of biomarkers of sepsis is presently available. The diagnostic spectrum of the various markers, however, is different. Some primarily indicate severity of inflammation (e.g. interleukin-6), others respond to infection, but do not indicate the host response well (endotoxin, lipoprotein binding protein, triggering receptor on myeloid cells). There are new markers with limited clinical experience, for example triggering receptor on myeloid cells or mid-pro atrial natriuretic peptide (Seristra, Brahms AG, Hennigsdorf, Germany). Procalcitonin is a well-established biomarker of sepsis that fulfills several criteria of clinical needs: it responds both to infection and severity of inflammation and thus has an impact on therapy. Recent studies indicate that antibiotic treatment can also be guided by procalcitonin. Further indications, including diagnosis of invasive bacterial infections and diagnosis of sepsis in neonates and children have been reported recently.

SUMMARY

Recent data and cumulative analyses indicate that biomarkers of sepsis improve diagnosis of sepsis. However, only a few markers have impact on therapy and fulfill the clinical requirements. Procalcitonin is a well-established marker, indicating infection, sepsis, and progression to the more severe stages of the disease. Today, this biomarker should be in the diagnostic portfolio of an intensive care unit or emergency ward.

Drotrecogin alfa (activated) for the treatment of severe sepsis and septic shock

Coagulopathy and systemic inflammation are almost universal in patients with severe sepsis. Interaction between the two results in an intense inflammatory response and microthrombi formation in the vessels of multiple organs, resulting in organ dysfunction or severe sepsis. Recombinant human activated protein C, also known as drotrecogin alfa (activated), possesses anti-inflammatory, antithrombotic, and profibrinolytic properties. Treatment with drotrecogin alfa (activated) significantly reduces morbidity and mortality in patients with severe sepsis. An increased risk of bleeding during the infusion was the only side effect experienced. Recent data demonstrate that early administration of drotrecogin alfa (activated) is associated with lower mortality rates. Despite concern over its relatively high cost, analysis has demonstrated that recombinant human activated protein C is as cost-effective as other commonly used treatments in the intensive care unit.

Lung, spleen, and kidney are the major places for inducible nitric oxide synthase expression in endotoxic shock: role of p38 mitogen-activated protein kinase in signal transduction of inducible nitric oxide synthase expression

Bacterial lipopolysaccharide (LPS) is known to induce endotoxic shock with inducible nitric oxide (NO) synthase (iNOS) expression and NO production. However, the major place for NO production in shock remains unclear. Although there is some literature about p38 mitogen-activated protein kinase (MAPK) in regulating LPS-induced iNOS expression, the results are contradictory. To interpret the precise cell mechanism and the role of p38 MAPK in the expression of iNOS during endotoxic shock, we carried out the following investigations. A severe endotoxic shock model was reproduced in mice 6 h after LPS injection. The plasma NO level was increased in a dose- and time-dependent manner after LPS stimulation and was suppressed by administration of SB203580 [4-(4-fluorophenyl)-2-4-methylsulfonylphenyl-5-(4-pyridyl) imidazole], a highly specific inhibitor of p38 MAPK. The iNOS expression was increased in many organs, including heart, liver, spleen, lung, gut, and kidney in endotoxic shock. Among them, the highest expression of iNOS mRNA and protein was in the lung, moderate expression was in the spleen and kidney, and the lowest expression was in the heart, gut, and liver. The level of expression in lung was 5.5 times that of iNOS mRNA and was 3.1 times that of iNOS protein than in heart, and 1.6 and 1.8 times that of iNOS mRNA and 1.7 and 1.4 times that of iNOS protein than in spleen and kidney, respectively. The p38 MAPK activity increased after LPS injection, and SB203580 markedly reduced LPS-induced expressions of iNOS protein and mRNA in the lung. The results indicates that lung, spleen, and kidney are the major places for iNOS expression in endotoxic shock and are important therapeutic target organs for attenuating NO production in shock treatment.

Procalcitonin, C-reactive protein and leukocyte count in children with lower respiratory tract infection

BACKGROUND

Lower respiratory tract infection is the most common infection leading to unnecessary antibiotic treatment in children. Etiologic diagnosis is not immediately achieved, and the pathogen remains unidentified in a large number of cases. Neither clinical nor laboratory factors allow for a rapid distinction between bacterial and viral etiology. The aim of our study was to evaluate the reliability of procalcitonin (PCT), C-reactive protein (CRP) and leukocyte count in distinguishing pneumococcal, atypical and viral lower respiratory tract infection.

METHODS

PCT, CRP and leukocyte count were measured in children with microbiologically documented diagnoses of lower respiratory tract infection. The results were compared of children with pneumococcal, atypical and viral etiologies.

RESULTS

PCT and CRP showed significant correlation with a bacterial etiology of lower respiratory tract infection. No significance was found for leukocyte count. Using a cutoff point of 2 ng/ml for PCT and 65 mg/l for CRP, the sensitivities and specificities for distinguishing bacterial from viral lower respiratory tract infections were 68.6 and 79.4% for PCT and 79.1 and 67.1% for CRP. The sensitivities and specificities for distinguishing pneumococcal from other etiologies were 90.3 and 74.1% for PCT and 90.3 and 60% for CRP, respectively.

CONCLUSIONS

High PCT and CRP values show a significant correlation with the bacterial etiology of lower respiratory tract infection. PCT and CRP show good sensitivity for distinguishing pneumococcal from other etiologies. PCT shows higher specificity than CRP. PCT and CRP can help make decisions about antibiotic therapy in children with lower respiratory tract infections.

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.

Drotrecogin alfa (activated) (recombinant human activated protein C) for the treatment of severe sepsis

OBJECTIVE

To review the data supporting drotrecogin alfa (activated) for severe sepsis treatment.

DATA SOURCES

Published research and data from the Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) trial.

DATA EXTRACTION AND SYNTHESIS

The coagulation cascade and intense inflammation play a central role in the development of organ failure due to severe sepsis. Drotrecogin alfa (activated) has anti-inflammatory, antithrombotic, profibrinolytic, and other properties that may explain the beneficial results seen in both animal models and humans with severe sepsis. Drotrecogin alfa (activated) produces a robust reduction in the mortality rate of patients with severe sepsis that is evident across nearly every subgroup examined in the phase III clinical trial and has an acceptable safety profile with bleeding during infusion as the only significant risk associated with therapy. The relative risk reductions for mortality seen in Gram-negative, Gram-positive, pneumonia, abdominal sources, shock, and nonshock are similar to the intent-to-treat population, 19.4%. Treatment also increases days alive and free from mechanical ventilation and shock.

CONCLUSIONS

Coagulopathy and systemic inflammation are almost universal in patients with severe sepsis. Treatment of this disorder with drotrecogin alfa (activated) directly addresses these derangements and substantially reduces morbidity and mortality rates with potential for bleeding during infusion as the only known risk.

Flow cytometric analysis of procalcitonin expression in human monocytes and granulocytes

Procalcitonin (PCT), a precursor of calcitonin is a useful indicator of severe systemic infection and sepsis. For a better understanding of the pathophysiological background of PCT induction, a study was made of the intracellular expression of PCT in various human white blood cell populations-i.e. monocytes and polymorphonuclear granulocytes (PMNs)-and the role of TNF-alpha in the stimulation of their PCT production. The expression of PCT was investigated by flow cytometric analysis with intracellular staining with antibodies to the PCT components calcitonin (CT) and katacalcin (KC). Both human peripheral monocytes and granulocytes expressed PCT, and increased intracellular amounts of the PCT components were demonstrated after stimulation with Staphylococcus aureus as TNF-alpha inducer. The S. aureus induced stimulation of PCT production was inhibited by anti-TNF-alpha monoclonal antibodies. The monocytic cell line U937 expressed considerable intracellular PCT, but S. aureus failed to induce an increase in PCT expression. The determination of intracellular PCT by flow cytometry is a promising and a sensitive method for further investigation of the effects of various cytokines and cytokine-inducing agents in PCT synthesis of human monocytes and granulocytes.

Procalcitonin amplifies inducible nitric oxide synthase gene expression and nitric oxide production in vascular smooth muscle cells

OBJECTIVE

Elevated procalcitonin concentrations are found in the course of systemic inflammation caused by bacterial insults, for example, sepsis and septic shock. However, the source of procalcitonin and its role in the inflammatory process are still unknown. In clinical studies, procalcitonin concentrations reflected the severity of sepsis and were predictive of mortality, suggesting that an increased procalcitonin synthesis is detrimental for the host. In contrast, and data report anti-inflammatory effects of procalcitonin that rather may represent a benefit for the septic patient.

DESIGN

Prospective, controlled, cell culture study.

SETTING

University research laboratories.

SUBJECTS

WKY rats.

INTERVENTIONS

We investigated whether procalcitonin affects one principal mediator of sepsis, inducible nitric oxide synthase-derived nitric oxide, taking into account the typical 3-hr delay of procalcitonin increase following a bacterial challenge. Vascular smooth muscle cells were incubated with lipopolysaccharide (10 microg/mL), tumor necrosis factor-alpha (500 units/mL), interferon-gamma (100 units/mL), and procalcitonin (1, 10, 100, and 1000 ng/mL). Cells were preincubated with lipopolysaccharide for 90 mins followed by the addition of tumor necrosis factor-alpha/interferon-gamma. In a second set of experiments, procalcitonin was added to these proinflammatory agonists 3 hrs after lipopolysaccharide application.

MEASUREMENTS AND MAIN RESULTS

Although no inducible nitric oxide synthase complementary DNA was detectable in unstimulated controls and following single application of procalcitonin, inducible nitric oxide synthase gene expression was induced in cells treated with lipopolysaccharide plus tumor necrosis factor-alpha/interferon-gamma for a total incubation time of 24 hrs. When vascular smooth muscle cells were incubated with procalcitonin in addition to lipopolysaccharide plus tumor necrosis factor-alpha/interferon-gamma, a further stimulation of inducible nitric oxide synthase transcription rate could be detected.

CONCLUSIONS

These results provide evidence that procalcitonin acts as a modulator that augments the inflammatory response triggered by agonists like lipopolysaccharide, tumor necrosis factor-alpha, and interferon-gamma. Although not effective as a single stimulus, it might contribute to the detrimental outcome following excessive activation of the inflammatory cascade.

Pathobiochemistry and clinical use of procalcitonin

Induction of the protein procalcitonin during infection and inflammation was first described approximately 10 years ago. A large number of publications, primarily clinical studies, demonstrate the increasing use of procalcitonin in modern clinical practice. However, data on the biological function and origin of procalcitonin is scarce. Findings regarding the possible role and source of procalcitonin in sepsis and infection were recently published, and the pathophysiology of the protein has meanwhile been investigated in various experimental models. Procalcitonin obviously has certain biological functions, and it is also known to be specifically induced. Given the hormonal origin of the mature protein and the inflammation-related functions of its propeptides, some investigators suggest that procalcitonin should be referred to as a "hormokine," although its biological functions should be studied in more detail. This review will survey the data now available in recent publications on the induction, production sources, possible biological functions and clinical uses of procalcitonin.

Migration of human monocytes in response to procalcitonin

OBJECTIVE

Circulating serum levels of procalcitonin rise significantly during bacterial infection. Because calcitonin is known to be a monocyte chemoattractant, we investigated whether procalcitonin, a prohormone of calcitonin, also affects leukocyte migration.

DESIGN

Prospective, controlled in vitro study.

SETTING

University research laboratories.

INTERVENTIONS

Forearm venous blood polymorphonuclear neutrophils and monocytes were isolated from healthy human donors. Cell migration was assessed in a blindwell chemotaxis chamber. The distance of migration into filter micropores was measured. To biochemically confirm functional data on cell migration, effects of procalcitonin on cellular levels of cyclic adenosine monophosphate were measured by high-performance liquid chromatography.

MEASUREMENTS AND MAIN RESULTS

Both procalcitonin and calcitonin elicited dose-dependent migration of monocytes at concentrations from the femtomolar to the micromolar range. Neutrophils did not migrate toward procalcitonin or calcitonin, nor was their oxygen free radical release affected as measured fluorimetrically. Checkerboard analysis of monocyte locomotion revealed procalcitonin-induced migration as true chemotaxis. Pretreatment of monocytes with procalcitonin or calcitonin rapidly deactivated their migratory response to formyl-Met-Leu-Phe, and both also induced homologous deactivation of migration. Procalcitonin elevated levels of cyclic adenosine monophosphate in monocytes.

CONCLUSIONS

In vitro procalcitonin is a monocyte chemoattractant that deactivates chemotaxis in the presence of additional inflammatory mediators. Procalcitonin stimulates cyclic adenosine monophosphate production in monocytes, suggesting that its action may be specific and comparable with calcitonin, which exerts similar functions.

Nitric oxide: does it play a role in the heart of the critically ill?

Nitric oxide regulates many aspects of myocardial function, not only in the normal heart but also in ischemic and nonischemic heart failure, septic cardiomyopathy, cardiac allograft rejection, and myocarditis. Accumulating evidence implicates the endogenous production of nitric oxide in the regulation of myocardial contractility, distensibility, heart rate, coronary vasodilation, myocardial oxygen consumption, mitochondrial respiration, and apoptosis. The effects of nitric oxide promote left ventricular mechanical efficiency, ie, appropriate matching between cardiac work and myocardial oxygen consumption. Most of these beneficial effects are attributed to the low physiologic concentrations generated by the constitutive endothelial or neuronal nitric oxide synthase. By contrast, inducible nitric oxide synthase generates larger concentrations of nitric oxide over longer periods of time, leading to mostly detrimental effects. In addition, the recently identified beta3-adrenoceptor mediates a negative inotropic effect through coupling to endothelial nitric oxide synthase and is overexpressed in heart failure. An imbalance between beta 1 and beta2-adrenoceptor and beta3-adrenoceptor, with a prevailing influence of beta3-adrenoceptor, may play a causal role in the pathogenesis of cardiac diseases such as terminal heart failure. Likewise, changes in the expression of endothelial nitric oxide synthase or inducible nitric oxide synthase within the myocardium may alter the delicate balance between the effects of nitric oxide produced by either of these isoforms. New treatments such as selective inducible nitric oxide synthase blockade, endothelial nitric oxide synthase promoting therapies, and selective beta3-adrenoceptor modulators may offer promising new therapeutic approaches to optimize the care of critically ill patients according to their stage and specific underlying disease process.