Systemic neuropeptide levels as predictive indicators for lethal outcome in patients with postoperative sepsis

Peripheral ischemic reserve in sepsis and septic shock as a new bedside prognostic enrichment tool: A Brazilian cohort study

Microvascular dysfunctions are associated with poor prognosis in sepsis. However, the potential role of clinical assessment of peripheral ischemic microvascular reserve (PIMR), a parameter that characterizes the variation of peripheral perfusion index (PPI) after brief ischemia of the upper arm, as a tool to detect sepsis-induced microvascular dysfunction and for prognostic enrichment has not been established. To address this gap, this study investigated the association of high PIMR with mortality over time in patients with sepsis and its subgroups (with and without shock) and peripheral perfusion (capillary-refill time). This observational cohort study enrolled consecutive septic patients in four Intensive-care units. After fluid resuscitation, PIMR was evaluated using the oximetry-derived PPI and post-occlusive reactive hyperemia for two consecutive days in septic patients. Two hundred and twenty-six patients were included-117 (52%) in the low PIMR group and 109 (48%) in the high PIMR group. The study revealed differences in mortality between groups on the first day, which was higher in the high PIMR group (RR 1.25; 95% CI 1.00-1.55; p = 0.04) and maintained its prognostic significance after multivariate adjustment. Subsequently, this analysis was made for sepsis subgroups and showed significant differences in mortality only for the septic-shock subgroup, with was higher in the high PIMR group (RR 2.14; 95% CI 1.49-3.08; p = 0.01). The temporal ΔPPI peak values (%) analyses did not demonstrate maintenance of the predictive value over the first 48 h in either group (p > 0.05). A moderate positive correlation (r = 0.41) between ΔPPI peak (%) and capillary-refill time (s) was found within the first 24 hours of diagnosis (p < 0.001). In conclusion, detecting a high PIMR within 24 h appears to be a prognostic marker for mortality in sepsis. Furthermore, its potential as a prognostic enrichment tool seems to occur mainly in septic shock.

Hydrogen Sulfide and Substance P Levels in Patients with Escherichia coli and Klebsiella pneumoniae Bacteraemia

Hydrogen sulfide (H2S) and substance P (SP) are known from animal models and in vitro studies as proinflammatory mediators. In this study, peripheral blood concentrations of H2S and SP were measured in patients with Escherichia coli or Klebsiella pneumoniae bacteraemia. Fifty patients were recruited from general wards at Christchurch Hospital, during 2020–2021. Samples from age- and sex-matched healthy subjects previously recruited as controls for studies of cardiovascular disease were used as controls. The concentrations of H2S were higher than controls on day 0, day 1, and day 2, and SP was higher than controls on all 4 days. The concentrations of H2S were highest on day 0, whereas SP concentrations were higher on day 2 than other days. Interleukin-6 and C-reactive protein were significantly higher on day 0 and day 1, respectively. The concentrations of H2S and SP did not differ between 15 non-septic (SIRS 0-1) and the 35 septic subjects (SIRS ≥ 2). Substance P concentrations were higher in subjects with abdominal infection than urinary tract infections on day 0 (p = 0.0002) and day 1 (p = 0.0091). In conclusion, the peak H2S concentrations precede the SP peak in patients with Gram-negative bacteraemia, but this response varies with the site of infection.

Current Epidemiology of Surgical Sepsis: Discordance Between Inpatient Mortality and 1-year Outcomes

OBJECTIVE

We sought to compare traditional inpatient outcomes to long-term functional outcomes and mortality of surgical intensive care unit (SICU) patients with sepsis.

SUMMARY OF BACKGROUND DATA

As inpatient sepsis mortality declines, an increasing number of initial sepsis survivors now progress into a state of chronic critical illness (CCI) and their post-discharge outcomes are unclear.

METHODS

We performed a prospective, longitudinal cohort study of SICU patients with sepsis.

RESULTS

Among this recent cohort of 301 septic SICU patients, 30-day mortality was 9.6%. Only 13 (4%) patients died within 14 days, primarily of refractory multiple organ failure (62%). The majority (n = 189, 63%) exhibited a rapid recovery (RAP), whereas 99 (33%) developed CCI. CCI patients were older, with greater comorbidities, and more severe and persistent organ dysfunction than RAP patients (all P < 0.01). At 12 months, overall cohort performance status was persistently worse than presepsis baseline (WHO/Zubrod score 1.4 ± 0.08 vs 2.2 ± 0.23, P > 0.0001) and mortality was 20.9%. Of note at 12 months, the CCI cohort had persistent severely impaired performance status and a much higher mortality (41.4%) than those with RAP (4.8%) after controlling for age and comorbidity burden (Cox hazard ratio 1.27; 95% confidence interval, 1.14-1.41, P < 0.0001). Among CCI patients, independent risk factors for death by 12 months included severity of comorbidities and persistent organ dysfunction (sequential organ failure assessment ≥6) at day 14 after sepsis onset.

CONCLUSIONS

There is discordance between low inpatient mortality and poor long-term outcomes after surgical sepsis, especially among older adults, increasing comorbidity burden and patients that develop CCI. This represents important information when discussing expected outcomes of surgical patients who experience a complicated clinical course owing to sepsis.

[Association between peripheral perfusion, microcirculation and mortality in sepsis: a systematic review]

Although increasing evidence supports the monitoring of peripheral perfusion in septic patients, no systematic review has been undertaken to explore the strength of association between poor perfusion assessed in microcirculation of peripheral tissues and mortality. A search of the most important databases was carried out to find articles published until February 2018 that met the criteria of this study using different keywords: sepsis, mortality, prognosis, microcirculation and peripheral perfusion. The inclusion criteria were studies that assessed association between peripheral perfusion/microcirculation and mortality in sepsis. The exclusion criteria adopted were: review articles, animal/pre-clinical studies, meta-analyzes, abstracts, annals of congress, editorials, letters, case-reports, duplicate and articles that did not present abstracts and/or had no text. In the 26 articles were chosen in which 2465 patients with sepsis were evaluated using at least one recognized method for monitoring peripheral perfusion. The review demonstrated a heterogeneous critically ill group with a mortality-rate between 3% and 71% (median=37% [28%-43%]). The most commonly used methods for measurement were Near-Infrared Spectroscopy (NIRS) (7 articles) and Sidestream Dark-Field (SDF) imaging (5 articles). The vascular bed most studied was the sublingual/buccal microcirculation (8 articles), followed by fingertip (4 articles). The majority of the studies (23 articles) demonstrated a clear relationship between poor peripheral perfusion and mortality. In conclusion, the diagnosis of hypoperfusion/microcirculatory abnormalities in peripheral non-vital organs was associated with increased mortality. However, additional studies must be undertaken to verify if this association can be considered a marker of the gravity or a trigger factor for organ failure in sepsis.

Identification of swine protein biomarkers of inflammation-associated pain

This study sought to determine if proteins associated with pain in humans could be measured using a swine in vitro model of inflammation. This would constitute the first step towards using them as surrogate endpoints to help support effectiveness indications for investigational new animal drugs to control pain in swine. Swine whole blood samples were cultured in vitro with E. coli derived-lipopolysaccharide (LPS) or without LPS for 24 h. Supernatants from these cultures were collected to determine the concentration of proteins associated with pain and whether the levels were altered in response to LPS-induced inflammation. Bradykinin protein levels steadily increased over time due to LPS stimulation and returned to 0 h levels after 6 h of culture. Corticotrophin-releasing factor protein levels were not affected by LPS. Substance-P protein trended towards increasing concentrations after LPS stimulation, following a time-concentration profile similar to that observed with bradykinin. These results suggest that 2 biomarkers may be useful as surrogate endpoints for evaluation of pain.

Perfusion index for assessing microvascular reactivity in septic shock after fluid resuscitation

Objective

Microcirculation disturbances are implicated in the prognosis of septic shock. Microvascular hyporesponsiveness can be assessed by an oximetry-derived perfusion index and reactive hyperemia. Using this perfusion index, we investigated reactive hyperemia and its relationship with peripheral perfusion and clinical-hemodynamic parameters in septic shock.

Methods

Eighty-two patients were evaluated: 47 with septic shock and 35 controls. Tests were performed within 24 hours after admission. The perfusion index was evaluated before and after a 3-min blood flow occlusion using a time-response analysis for 5 min. The perfusion index was also evaluated in the hyperemic phases and was mainly derived by mechanosensitive (ΔPI_0-60) and metabolic mechanisms (ΔPI_60-120). Correlation tests were performed between reactive hyperemia and clinical-hemodynamic data.

Results

Reactive hyperemia measured by the perfusion index was significantly lower in patients with septic shock, but this was only observed for the first 45 seconds after cuff-deflation. In the remaining period, there were no statistical differences between the groups. The peaks in the perfusion index were similar between groups, although the peak was reached more slowly in the septic group. Values of ΔPI_0-60 were lower in shock [01% (-19% - -40%) versus 39% (6% - 75%); p = 0.001]. However, ΔPI_60-120 was similar between the groups [43% (18% - 93%) versus 48% (18% - 98%); p = 0.58]. The time-to-peak of the perfusion index was correlated positively with the SOFA scores and negatively with C-reactive protein; the peak of the perfusion index was positively correlated with vasopressor doses; and the ΔPI_60-120 values were positively correlated with C-reactive protein and vasopressor doses. No other significant correlations occurred.

Conclusions

This perfusion index-based study suggests that septic shock promotes initial peripheral vascular hyporesponsiveness and preserves posterior vascular reactivity to a considerable degree. These results demonstrate a time-dependent peripheral hyperemic response and a significant ischemic reserve in septic shock.

Pathological Role and Diagnostic Value of Endogenous Host Defense Peptides in Adult and Neonatal Sepsis: A Systematic Review

BACKGROUND

Sepsis is a systemic host response to an infection leading to organ failure. This is associated with dynamic expression of endogenous host defense peptides. Dysregulation of these peptides is associated with septic morbidity and mortality.

METHODS

We performed a systematic search of articles indexed in PubMed, ISI Web of Knowledge, EmBase, and Scopus database from inception to October 2016. Both preclinical and clinical studies investigating the role of host defense peptides in pathogenesis and as biomarkers for sepsis were included.

RESULTS

Of the available literature, cathelicidin, defensin, and hepcidin are among the best-characterized peptides. These regulate immune response, and crosstalk with pyroptosis and coagulation cascades. The applicability of these peptides as septic biomarkers has been investigated in vitro and in vivo studies. However, numerous studies were based on endotoxemia without an infection, jeopardizing interpretation of the outcomes. Cathelicidin and defensin were frequently reported in adult sepsis while hepcidin in neonatal sepsis. The expression level of these peptides is significantly associated with septic condition. Most of the studies employed a cross-sectional design, precluding the establishment of a temporal relationship between candidate peptide biomarkers and sepsis.

CONCLUSIONS

Innate defense peptides have been insufficiently evaluated as either diagnostic or prognostic biomarkers. In the future, evaluation of host defense peptides as septic biomarkers may employ a longitudinal design and consider a panel of multiple peptides.

Sustained Low Serum Substance P Levels in Non-Surviving Septic Patients

Previously, researchers found higher serum substance P (SP) concentrations in survivors of severe sepsis than in non-survivors at the time of severe sepsis diagnosis. The objectives of our current study were to determine whether there is an association between serum SP levels during the first week and sepsis mortality, sepsis severity, serum levels of tumor necrosis factor (TNF)-α and interleukin (IL)-10, and whether serum SP levels during the first week could be used as a biomarker of sepsis mortality. We determined serum concentration of SP, TNF-α, and IL-10 at days 1, 4, and 8. The end-point of the study was mortality at 30 days. We found that non-survivor (n = 104) compared to survivor patients (n = 206) showed lower serum SP levels at days 1, 4, and 8 (p < 0.001). Multiple logistic regression analyses showed an association between 30-day mortality and serum SP levels at days 1, 4, and 8 (p < 0.001) controlling for SOFA score, diabetes mellitus, age, and lactic acid levels. The most interesting findings of our study were that there is an association between serum SP levels during the first week and sepsis mortality, and that serum SP levels during the first week could be used as a biomarker of sepsis mortality.

N-Arachidonoyl Dopamine Modulates Acute Systemic Inflammation via Nonhematopoietic TRPV1

N-Arachidonoyl dopamine (NADA) is an endogenous lipid that potently activates the transient receptor potential vanilloid 1 (TRPV1), which mediates pain and thermosensation. NADA is also an agonist of cannabinoid receptors 1 and 2. We have reported that NADA reduces the activation of cultured human endothelial cells by LPS and TNF-α. Thus far, in vivo studies using NADA have focused on its neurologic and behavioral roles. In this article, we show that NADA potently decreases in vivo systemic inflammatory responses and levels of the coagulation intermediary plasminogen activator inhibitor 1 in three mouse models of inflammation: LPS, bacterial lipopeptide, and polymicrobial intra-abdominal sepsis. We also found that the administration of NADA increases survival in endotoxemic mice. Additionally, NADA reduces blood levels of the neuropeptide calcitonin gene-related peptide but increases the neuropeptide substance P in LPS-treated mice. We demonstrate that the anti-inflammatory effects of NADA are mediated by TRPV1 expressed by nonhematopoietic cells and provide data suggesting that neuronal TRPV1 may mediate NADA's anti-inflammatory effects. These results indicate that NADA has novel TRPV1-dependent anti-inflammatory properties and suggest that the endovanilloid system might be targeted therapeutically in acute inflammation.

Antagonism of the Neurokinin-1 Receptor Improves Survival in a Mouse Model of Sepsis by Decreasing Inflammation and Increasing Early Cardiovascular Function

OBJECTIVES

Sepsis remains a serious clinical problem despite intensive research efforts and numerous attempts to improve outcome by modifying the inflammatory response. Substance P, the principal ligand for the neurokinin-1 receptor, is a potent proinflammatory mediator that exacerbates inflammatory responses and cardiovascular variables in sepsis.

DESIGN

The current study examined whether inhibition of the neurokinin-1 receptor with a specific antagonist (CJ-12,255) would improve survival in the cecal ligation and puncture model of sepsis in adult female outbred mice.

SETTING

University basic science research laboratory.

MEASUREMENTS AND MAIN RESULTS

Neurokinin-1 receptor treatment at the initiation of sepsis improved survival in cecal ligation and puncture sepsis (neurokinin-1 receptor antagonist survival = 79% vs vehicle = 54%). Delaying therapy for as little as 8 hours postcecal ligation and puncture failed to provide a survival benefit. Neurokinin-1 receptor antagonist treatment did not prevent the sepsis-induced decrease in circulating WBCs, augment the early (6 hr postcecal ligation and puncture) recruitment of inflammatory cells to the peritoneum, or improve phagocytic cell killing of pathogens. However, the neurokinin-1 receptor antagonist significantly reduced both circulating and peritoneal cytokine concentrations. In addition, the cardiovascular variable, pulse distension (a surrogate for stroke volume) was improved in the neurokinin-1 receptor antagonist group during the first 6 hours of sepsis, and there was a significant reduction in loss of fluid into the intestine.

CONCLUSION

These data show that early activation of the neurokinin-1 receptor by substance P decreases sepsis survival through multiple mechanisms including depressing stroke volume, increasing fluid loss into the intestine, and increasing inflammatory cytokine production.

Association between serum substance P levels and mortality in patients with severe sepsis

BACKGROUND

Substance P (SP) is a peptide of the tachykinins family involved in the inflammatory response. Circulating SP levels have been assessed in septic patients in 2 previous studies with a small number of subjects (61 and 42 patients, respectively), and there were no significant differences in SP levels at the moment of sepsis diagnosis between surviving and nonsurviving patients. The main goal of this study was to determine a possible relationship between serum SP levels and patient outcome in the largest cohort of severe septic patients analyzed so far.

METHODS

We performed an observational, prospective, multicenter study in 6 Spanish intensive care units. Serum SP levels were measured at the moment of severe sepsis diagnosis in 238 patients. The end point of the study was 30-day mortality.

RESULTS

We found that surviving septic patients (n = 153) showed higher serum SP levels than did nonsurvivors (n = 85). Multiple logistic regression analysis showed that serum SP levels higher than 350 pg/mL were associated with survival at 30 days (odds ratio, 0.43; 95% confidence interval, 0.24-0.77; P = .005) after controlling for serum lactic acid levels and Sepsis-related Organ Failure Assessment score.

CONCLUSIONS

The major new finding of our study was that serum SP levels were associated with mortality in severe septic patients.

Neuroimmunological communication via CGRP promotes the development of a regulatory phenotype in TLR4-stimulated macrophages

Environmental signals shape the phenotype and function of activated macrophages. Here, we show that the neuropeptide calcitonin gene-related peptide (CGRP), which is released from sensory nerves, modulates the phenotype of TLR4-activated murine macrophages by enhancing expression of the regulatory macrophage markers IL-10, sphingosine kinase 1 (SPHK1), and LIGHT (lymphotoxin-like, exhibits inducible expression and competes with HSV glycoprotein D for herpesvirus entry mediator, a receptor expressed by T lymphocytes). In contrast, CGRP inhibits production of cytokines characteristic of inflammatory macrophages and does not affect expression of wound-healing macrophage markers upon TLR4 engagement. In IL-4-stimulated macrophages, CGRP increased LIGHT expression, but failed to induce IL-10 and SPHK1. The stimulatory effect of CGRP on IL-10 production required activation of protein kinase A and was linked to prolonged phosphorylation of CREB and sustained nuclear accumulation of CRTC2 and CRTC3 (where CRTC is CREB-regulated transcriptional cofactor). CGRP enhanced expression of regulatory macrophage markers during the early, but not late, phase of LPS-stimulation and this effect was independent of autocrine type-I IFN activity. In contrast, autocrine type-I IFN activity and treatment of macrophages with IFN-β promoted late-phase IL-10 production, but had only minor influence on LIGHT and SPHK1 expression. Together, the results identify neuroimmunological communication through CGRP as a novel costimulatory pathway promoting the development of a regulatory phenotype of TLR4-stimulated macrophages. CGRP appears to act through a mechanism that involves sustained activation of CREB-dependent gene transcription.

Changes in urine levels of substance P, vasoactive intestinal peptide and calcitonin-gene-related peptide in patients with urinary tract infections

Urinary tract infections (UTI) are important health problems and predisposing causes of UTI are not entirely known. Neuro-immune interactions play an important role in human health and disease. Capsaicin-sensitive sensory nerves which in nerve bladder extensively regulate immune system through neuropeptides such as substance P (SP), calcitonin-gene related peptide (CGRP) and vasoactive intestinal peptide (VIP). In addition these neuropeptides also have anti-bacterial effects. To determine how the levels of these peptides changes during UTI, 67 patients (50-90 years-old) diagnosed with UTI in Akdeniz University Faculty of Medicine Hospital were compared with 37 healthy people 50 years or older as the control group. Additionally, 7 patients with UTI symptoms (dysuria, urgency) but with sterile pyuria were also included in the study. Urine samples from 15 patients, whose symptoms regressed with control urine cultures being sterile, were taken after completion of the treatments. Urine neuropeptide levels were determined by ELISA. CGRP levels are significantly higher in patients with UTI, but did not associate with pyuria whereas SP and VIP levels were significantly lower in patients with sterile pyuria, indicating sensory nerve deficiency. Since CGRP exerts immunosuppressive effects, increased levels of the peptide may predispose to UTI. Furthermore, the connection between the observed sensory nerve deficiency and sterile pyuria warrants further studies.

TRPV1 and SP: key elements for sepsis outcome?

Sensory neurons play important roles in many disorders, including inflammatory diseases, such as sepsis. Sepsis is a potentially lethal systemic inflammatory reaction to a local bacterial infection, affecting thousands of patients annually. Although associated with a high mortality rate, sepsis outcome depends on the severity of systemic inflammation, which can be directly influenced by several factors, including the immune response of the patient. Currently, there is a lack of effective drugs to treat sepsis, and thus there is a need to develop new drugs to improve sepsis outcome. Several mediators involved in the formation of sepsis have now been identified, but the mechanisms underlying the pathology remain poorly understood. The transient receptor potential vanilloid 1 (TRPV1) receptor and the neuropeptide substance P (SP) have recently been demonstrated as important targets for sepsis and are located on sensory neurones and non-neuronal cells. Herein, we highlight and review the importance of sensory neurones for the modulation of sepsis, with specific focus on recent findings relating to TRPV1 and SP, with their distinct abilities to alter the transition from local to systemic inflammation and also modify the overall sepsis outcome. We also emphasize the protective role of TRPV1 in this context.

LINKED ARTICLES

This article is part of a themed section on Neuropeptides. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.170.issue-7.

Deficiency of alpha-calcitonin gene-related peptide induces inflammatory responses and lethality in sepsis

In the present study, we examined the role of alpha-calcitonin gene-related peptide (αCGRP) on expression of neuropeptides in the brain, inflammatory responses, and survival rate in septic shock condition. We examined expression of neuropeptides such as αCGRP, proopiomelanocortin (POMC), corticotrophin releasing hormone (CRH), and proenkephalin (ProENK) in the hippocampus and hypothalamus in C57BL/6 (WT) or αCGRP-/- (KO) mice subjected to sepsis. Cecal ligation and puncture (CLP) or lipopolysaccharide/D-galactosamine (LPS/D-GalN) treatment showed significant increases of hippocampal and hypothalamic αCGRP, POMC, CRH, and ProENK mRNA levels in WT mice, but not ProENK mRNA in the hypothalamus at 6h after on-set of sepsis. However, enhanced mRNA levels of POMC, CRH, and ProENK genes were not increased in the hippocampus and hypothalamus of CLP-subjected KO mice at 6h following sepsis. KO mice treated with LPS/D-GalN displayed a significant enhancement of plasma corticosterone, aspartate aminotransferase, and alanine aminotransferase levels compared to LPS/D-GalN treated WT mice at 12h after induction of sepsis. In addition, plasma levels of pro-inflammatory cytokines, such as IL-1β and TNF-α, were also further increased in KO mice compared to WT mice at 24h after CLP or LPS/D-GalN treatment. Interestingly, mRNA expressions of IL-6 and IL-10, anti-inflammatory cytokines, were synergistically enhanced in liver and lymph node of KO mice compared to WT mice at 6h after CLP. However, plasma level of IL-10 but not IL-6 was significantly decreased in KO mice compared to WT mice at 24h after CLP or LPS/D-GalN challenge. The survival rate of KO mice was significantly reduced compared to WT mice following mild (1 punch) and moderate (2 punch) CLP and LPS/D-GalN administration. Taken together, our findings suggest that the activation of αCGRP may induce other neuropeptides associated with immunomodulation at CNS level and modulate immune responses as enhancing anti-inflammatory cytokines and reducing pro-inflammatory cytokines during the sepsis.

Neuropeptides in sepsis: from brain pathology to systemic inflammation

Septic encephalopathy is frequently diagnosed in critically ill patients and in up to 70% of patients with severe systemic infection [19]. The syndrome is defined by diffuse cerebral dysfunction or structural abnormalities attributed to the effects of systemic infection, rather than a direct central nervous system cause. The clinical characteristics can range from mild delirium to deep coma, but patients are often medically sedated making the diagnosis difficult. Any manifestation, however, is specific and markers of disease are lacking [43]. Sepsis survivors present long term cognitive impairment, including alterations of memory, attention and concentration [10,54]. Here, we propose that neuropeptides may play a key role in septic encephalopathy, leading to a vicious circle characterized by brain disease and systemic inflammation.

Altered serum stress neuropeptide levels in critically ill individuals and associations with lymphocyte populations

OBJECTIVE

Potential physiological correlates of stress and the role of stress neuropeptides, other than those of the hypothalamic-pituitary-adrenal axis, in critical illness have not been addressed. We investigated: (a) serum levels of stress neuropeptides (ACTH, substance P (SP), neuropeptide Y (NPY), cortisol, prolactin) in critically ill individuals compared to matched controls, (b) associations with lymphocyte counts, (c) associations among stress neuropeptide levels, and (d) associations with perceived intensity of stress, critical illness severity and survival.

METHODS

Correlational design with repeated measures. Thirty-six critically ill patients were followed up for 14 days compared to 36 healthy matched controls. Stress was assessed by the ICUESS scale. Correlations, cross-sectional comparisons and multiple regression models were pursued.

RESULTS

For the first time, we report lower SP (Difference of means (DM) = 2928-3286 ng/ml, p < 0.001) and NPY (DM = 0.77-0.83 ng/ml, p < 0.0001) levels in critically ill individuals compared to controls. Cortisol levels were higher (DM = 140-173 ng/ml, p<0.0001) and lymphocyte population counts (p < 0.002) were lower in patients throughout the study. NPY levels associated with lymphocyte (r = 0.411-0.664, p < 0.04), T-lymphocyte (r = 0.403-0.781, p< 0.05), T-helper (r = 0.492-0.690, p < 0.03) and T-cytotoxic cell populations (r = 0.39-0.740, p < 0.03). On day 1, cortisol levels exhibited associations with lymphocyte (r = -0.452, p = 0.01), T-cell (r = -0.446, p = 0.02), T-helper (r = -0.428, p = 0.026) and T-cytotoxic cells ( r = -0.426, p = 0.027). ACTH levels associated with NK cell counts (r = 0.326-0.441, p < 0.05). Associations among stress neuropeptides levels were observed throughout (p < 0.05). ACTH levels associated with disease severity (r = 0.340-0.387, p < 0.005). A trend for an association between ACTH levels and intensity of stress was noted (r = 0.340, p = 0.057).

CONCLUSION

The significantly lowered NPY and SP levels and the associations with cortisol, ACTH and lymphocytes suggest that the role of these peptides in critical illness merit further investigation. Future studies need to address associations between these neuropeptides and functional immune cell responses and inflammatory markers in critical illness.

Secondary and tertiary sulfonamides: a patent review (2008 - 2012)

INTRODUCTION

Secondary and tertiary sulfonamides (R-SO(2)NR(1)R(2)) are defined by the single or double N-alkyl or N-aryl/heteroaryl substitution of the primary sulfonamide respectively. They can be obtained easily by the classical S(N)2 or nucleophile acyl substitution displacements using the appropriate synthones. Many classes of compounds used in therapy present the substituted sulfonamide groups and there is also a continuous interest in different fields such as the herbicides herein schematically reported.

AREAS COVERED

The intent of this article is to give a comprehensive overview of the most important patents in the last decade related to pathologies of great interest. All selected patents claim new compounds bearing the secondary or/and tertiary sulfonamide moiety, and state to have biological activities. The article is neither intended for detailed discussions of the sulfonamides mode of action on the specific therapeutic targets, nor for their contribution to the physicochemical properties of the molecules they are introduced into, as the scientific literature in such topics is exhaustive and in many cases, debates are still ongoing. The main fields covered are related to pathologies affecting the CNS, cardiac disorders, anti-virals, inflammation diseases, glaucoma, bone remodeling, anti-cancer, and finally a section is also dedicated to herbicides.

EXPERT OPINION

The insertion of the secondary/tertiary sulfonamide group into the organic scaffolds is chemically straightforward and not associated to particular toxicity in the cells or in the organisms. Therefore, it is possible to create large libraries of compounds, which can be tested for different diseases. As demonstrated by the patents reported in the present review, the research in medicinal chemistry, and other fields, takes big advantages as new leads are created, and might be further developed.

Neurokinin-1 receptor antagonists for chemotherapy-induced nausea and vomiting: a systematic review

BACKGROUND

The addition of neurokinin-1 receptor (NK1R) antagonists to antiemetic regimens has substantially reduced chemotherapy-induced nausea and vomiting (CINV). We sought to systematically review the overall impact of NK1R antagonists on CINV prevention.

METHODS

We systematically searched the MEDLINE, EMBASE, and CENTRAL databases, and meeting proceedings for randomized controlled trials (RCTs) that evaluated NK1R antagonists plus standard antiemetic therapy for CINV prevention. Complete response (CR) to therapy was defined as the absence of emesis and the absence of rescue therapy. The endpoints were defined as CR in the overall phase (during the first 120 hours of chemotherapy), CR in the acute phase (first 24 hours), and the delayed phase (24-120 hours) after chemotherapy, nausea, and toxicity. Subgroup analyses evaluated the type of NK1R antagonist used, the emetogenic potential of the chemotherapy regimen, and prolonged use of 5-HT3 (serotonin) receptor antagonists, a class of standard antiemetic agents. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Statistical tests for heterogeneity were one-sided; statistical tests for effect estimates and publication bias were two-sided.

RESULTS

Seventeen trials (8740 patients) were included in this analysis. NK1R antagonists increased the CR rate in the overall phase from 54% to 72% (OR = 0.51, 95% CI = 0.46 to 0.57, P < .001). CR and nausea were improved in all phases and subgroups. The expected side effects from NK1R antagonists did not statistically significantly differ from previous reports; however, this analysis suggests that the incidence of severe infection increased from 2% to 6% in the NK1R antagonist group (three RCTs with a total of 1480 patients; OR = 3.10; 95% CI = 1.69 to 5.67, P < .001).

CONCLUSIONS

NK1R antagonists increased CINV control in the acute, delayed, and overall phases. They are effective for both moderately and highly emetogenic chemotherapy regimens. Their use might be associated with increased infection rates; however, additional appraisal of specific data from RCTs is needed.

Deficiency of the CGRP receptor component RAMP1 attenuates immunosuppression during the early phase of septic peritonitis

The neuropeptide CGRP contributes to the control of excessive cytokine production in endotoxemia models. However, the function of CGRP in sepsis caused by infection with viable pathogens is unknown. Here, we show that mice deficient for the CGRP receptor component RAMP1 have an improved anti-bacterial defense during the early, but not late, phase of polymicrobial septic peritonitis. The protective effect of Ramp1-deficiency was associated with reduced levels of IL-10 in plasma and peritoneal lavage fluid. Consistent with these findings, CGRP markedly increased IL-10 production of peritoneal and bone marrow-derived macrophages in response to short term stimulation with LPS in vitro. In addition, the lack of an intact CGRP receptor resulted in an increased recruitment and activation of neutrophils and caused an enhanced release of defensin-α1 in the peritoneal cavity. Considered together, our results identify the neuropeptide CGRP as a crucial immunosuppressive mediator impairing host defense during the early, but not late, phase of septic peritonitis.

TRPV1 deletion enhances local inflammation and accelerates the onset of systemic inflammatory response syndrome

The transient receptor potential vanilloid 1 (TRPV1) is primarily localized to sensory nerve fibers and is associated with the stimulation of pain and inflammation. TRPV1 knockout (TRPV1KO) mice show enhanced LPS-induced sepsis compared with wild type (WT). This implies that TRPV1 may have a key modulatory role in increasing the beneficial and reducing the harmful components in sepsis. We investigated immune and inflammatory mechanisms in a cecal ligation and puncture (CLP) model of sepsis over 24 h. CLP TRPV1KO mice exhibited significant hypothermia, hypotension, and organ dysfunction compared with CLP WT mice. Analysis of the inflammatory responses at the site of initial infection (peritoneal cavity) revealed that CLP TRPV1KO mice exhibited: 1) decreased mononuclear cell integrity associated with apoptosis, 2) decreased macrophage tachykinin NK(1)-dependent phagocytosis, 3) substantially decreased levels of nitrite (indicative of NO) and reactive oxygen species, 4) increased cytokine levels, and 5) decreased bacteria clearance when compared with CLP WT mice. Therefore, TRPV1 deletion is associated with impaired macrophage-associated defense mechanisms. Thus, TRPV1 acts to protect against the damaging impact of sepsis and may influence the transition from local to a systemic inflammatory state.

Modulation of immune responses by the neuropeptide CGRP

The peripheral nervous system is connected with lymphoid organs through sensory nerves that mediate pain reflexes and may influence immune responses through the release of neuropeptides such as calcitonin gene-related peptide (CGRP). Local and systemic levels of CGRP increase rapidly during inflammatory responses. CGRP inhibits effector functions of various immune cells and dampens inflammation by distinct pathways involving the amplification of IL-10 production and/or the induction of the transcriptional repressor inducible cAMP early repressor (ICER). Thus, available evidence suggests that, in neuro-immunological interactions, CGRP mediates a potent peptidergic anti-inflammatory pathway.

Hydrogen sulfide and neurogenic inflammation in polymicrobial sepsis: involvement of substance P and ERK-NF-κB signaling

Hydrogen sulfide (H₂S) has been shown to induce transient receptor potential vanilloid 1 (TRPV1)-mediated neurogenic inflammation in polymicrobial sepsis. However, endogenous neural factors that modulate this event and the molecular mechanism by which this occurs remain unclear. Therefore, this study tested the hypothesis that whether substance P (SP) is one important neural element that implicates in H₂S-induced neurogenic inflammation in sepsis in a TRPV1-dependent manner, and if so, whether H₂S regulates this response through activation of the extracellular signal-regulated kinase-nuclear factor-κB (ERK-NF-κB) pathway. Male Swiss mice were subjected to cecal ligation and puncture (CLP)-induced sepsis and treated with TRPV1 antagonist capsazepine 30 minutes before CLP. DL-propargylglycine (PAG), an inhibitor of H₂S formation, was administrated 1 hour before or 1 hour after sepsis, whereas sodium hydrosulfide (NaHS), an H₂S donor, was given at the same time as CLP. Capsazepine significantly attenuated H₂S-induced SP production, inflammatory cytokines, chemokines, and adhesion molecules levels, and protected against lung and liver dysfunction in sepsis. In the absence of H₂S, capsazepine caused no significant changes to the PAG-mediated attenuation of lung and plasma SP levels, sepsis-associated systemic inflammatory response and multiple organ dysfunction. In addition, capsazepine greatly inhibited phosphorylation of ERK_1/2 and inhibitory κBα, concurrent with suppression of NF-κB activation even in the presence of NaHS. Furthermore, capsazepine had no effect on PAG-mediated abrogation of these levels in sepsis. Taken together, the present findings show that H₂S regulates TRPV1-mediated neurogenic inflammation in polymicrobial sepsis through enhancement of SP production and activation of the ERK-NF-κB pathway.

Disruption of the transient receptor potential vanilloid 1 can affect survival, bacterial clearance, and cytokine gene expression during murine sepsis

BACKGROUND

Previous studies suggest that the transient receptor potential vanilloid 1 (TRPV1) channel has a role in sepsis, but it is unclear whether its effect on survival and immune response is beneficial or harmful.

METHODS

We studied the effects of genetic (Trpv1-knockout vs. wild-type [WT] mice) and pharmacologic disruption of TRPV1 with resiniferatoxin (an agonist) or capsazepine (an antagonist) on mortality, bacterial clearance, and cytokine expression during lipopolysaccharide or cecal ligation and puncture-induced sepsis.

RESULTS

After cecal ligation and puncture, genetic disruption of TRPV1 in Trpv1-knockout versus WT mice was associated with increased mortality risk (hazard ratio, 2.17; 95% CI, 1.23-3.81; P = 0.01). Furthermore, pharmacologic disruption of TRPV1 with intrathecal resiniferatoxin, compared with vehicle, increased mortality risk (hazard ratio, 1.80; 95% CI, 1.05-3.2; P = 0.03) in WT, but not in Trpv1-knockout, mice. After lipopolysaccharide, neither genetic (Trpv1 knockout) nor pharmacologic disruption of TRPV1 with resiniferatoxin had significant effect on survival compared with respective controls. In contrast, after lipopolysaccharide, pharmacologic disruption of TRPV1 with capsazepine, compared with vehicle, increased mortality risk (hazard ratio, 1.92; 95% CI, 1.02-3.61; P = 0.04) in WT animals. Furthermore, after cecal ligation and puncture, increased mortality in resiniferatoxin-treated WT animals was associated with higher blood bacterial count (P = 0.0004) and higher nitrate/nitrite concentrations and down-regulation of tumor necrosis factor α expression (P = 0.004) compared with controls.

CONCLUSIONS

Genetic or pharmacologic disruption of TRPV1 can affect mortality, blood bacteria clearance, and cytokine response in sepsis in patterns that may vary according to the sepsis-inducing event and the method of TRPV1 disruption.

Role of the transient receptor potential vanilloid 1 in inflammation and sepsis

The transient receptor potential vanilloid 1 (TRPV1) is a thermoreceptor that responds to noxious temperatures, as well as to chemical agonists, such as vanilloids and protons. In addition, its channel activity is notably potentiated by proinflammatory mediators released upon tissue damage. The TRPV1 contribution to sensory neuron sensitization by proalgesic agents has signaled this receptor as a prime target for analgesic and anti-inflammatory drug intervention. However, TRPV1 antagonists have notably failed in clinical and preclinical studies because of their unwanted side effects. Recent reports have unveiled previously unrecognized anti-inflammatory and protective functions of TRPV1 in several diseases. For instance, this channel has been suggested to play an anti-inflammatory role in sepsis. Therefore, the use of potent TRPV1 antagonists as a general strategy to treat inflammation must be cautiously considered, given the deleterious effects that may arise from inhibiting the population of channels that have a protective function. The use of TRPV1 antagonists may be limited to treating those pathologies where enhanced receptor activity contributes to the inflamed state. Alternatively, therapeutic paradigms, such as reduction of inflammatory-mediated increase of receptor expression in the cell surface, may be a better strategy to prevent abrogation of the TRPV1 subpopulation involved in anti-inflammatory and protective processes.

Sepsis biomarkers: a review

INTRODUCTION

Biomarkers can be useful for identifying or ruling out sepsis, identifying patients who may benefit from specific therapies or assessing the response to therapy.

METHODS

We used an electronic search of the PubMed database using the key words "sepsis" and "biomarker" to identify clinical and experimental studies which evaluated a biomarker in sepsis.

RESULTS

The search retrieved 3370 references covering 178 different biomarkers.

CONCLUSIONS

Many biomarkers have been evaluated for use in sepsis. Most of the biomarkers had been tested clinically, primarily as prognostic markers in sepsis; relatively few have been used for diagnosis. None has sufficient specificity or sensitivity to be routinely employed in clinical practice. PCT and CRP have been most widely used, but even these have limited ability to distinguish sepsis from other inflammatory conditions or to predict outcome.

Lipopolysaccharide induces calcitonin gene-related peptide in the RAW264.7 macrophage cell line

SUMMARY

Calcitonin gene-related peptide (CGRP) is widely distributed and plays important roles in a wide array of biological functions. It is enriched in primary sensory neurons and hence involved in nociception and neurogenic inflammation. Recent studies have shown that CGRP can be produced by immune cells such as monocytes/macrophages following inflammatory stimulation, suggesting a role in innate immunity. However, it is unclear how CGRP is up-regulated in macrophages and if it plays a role in macrophage functions such as the production of cytokines and chemokines. Using enzyme-linked immunosorbent assay (ELISA) and multiplex ELISA, lipopolysaccharide (LPS) was found to induce CGRP in the RAW 264.7 macrophage cell line. LPS-induced inflammatory mediators such as nerve growth factor (NGF), interleukin-1beta (IL-1beta), IL-6, prostaglandin E(2) (PGE(2)) and nuclear factor-kappaB (NF-kappaB) signalling are involved in inducing CGRP, whereas the NGF receptor trkA and CGRP receptor signalling pathways are unexpectedly involved in suppressing LPS-induced CGRP, which leads to the fine-tune regulation of CGRP release. Exogenous CGRP and CGRP receptor antagonists, in a concentration-dependent manner, stimulated, inhibited or had no effect on basal or LPS-induced release of monocyte chemoattractant protein-1, IL-1beta, IL-6, tumour necrosis factor-alpha and IL-10 in RAW macrophages. The ligand-concentration-dependent regulation of the production of inflammatory mediators by CGRP receptor signalling is a novel mechanism underlying the stimulating and suppressing role of CGRP in immune and inflammatory responses. Together, our data suggest that monocytes/macrophages are an important source of CGRP. Inflammation-induced CGRP has a positive or negative reciprocal effect on the production of other pro- and anti-inflammatory mediators. Thereby CGRP plays both facilitating and suppressing roles in immune and inflammatory responses.

Ghrelin attenuates acute pancreatitis-induced lung injury and inhibits substance P expression

OBJECTIVE

To investigate the effect of ghrelin administration on the severity of acute lung injury and on the production of proinflammatory cytokines and Substance P (SP) in rats with acute pancreatitis (AP).

METHODS

AP was induced in rats by sodium taurocholate injection through pancreaticobiliary duct. Ghrelin 20 nmol/kg was given before and after the treatment. Tumor necrosis factor-alpha, interleukin-1beta, and -6 levels in the serum were measured using the radioimmunoassay method. Morphological signs of lung injury, pulmonary water content, microvascular permeability, and myeloperoxidase activity were measured. Meanwhile, the determination of pulmonary SP mRNA level and its expression were performed by reverse transcriptase polymerase chain reaction and immunohistochemistry.

RESULTS

The serum proinflammatory cytokines, pulmonary water content, microvascular permeability, and myeloperoxidase activity were increased, and morphological damages were observed in the lung of AP rats. SP mRNA level and its expression were significantly higher in sham-operated rats (P < 0.05). Morphological damages were attenuated and serum cytokines and pulmonary parameters were reduced by pre- and posttreatment with ghrelin. Pulmonary SP expression was also significantly down-regulated by ghrelin (P < 0.05).

CONCLUSIONS

Ghrelin attenuates the severity of acute lung injury induced by AP. The reduction of neutrophil sequestration, limitation of proinflammatory cytokines release, and inhibition of pulmonary SP expression may be the mechanisms involved in the therapeutic effect of ghrelin.

Circulating levels of vasoactive peptides in patients with acute bacterial meningitis

PURPOSE

The underlying mechanisms for cerebral blood flow (CBF) abnormalities in acute bacterial meningitis (ABM) are largely unknown. Putative mediators include vasoactive peptides, e.g. calcitonin-gene related peptide (CGRP), vasoactive intestinal peptide (VIP), and endothelin-1 (ET-1), all of which may be affected by therapeutic interventions used in the intensive care unit. We measured arterial levels as well as the net cerebral flux of these peptides in patients with ABM, and in healthy volunteers undergoing interventions relevant to intensive care.

METHODS

Seven patients with severe ABM and sepsis and fifteen healthy volunteers were included after informed consent. The net cerebral fluxes of vasoactive peptides were measured by the Kety-Schmidt technique in ABM patients (baseline study only), as well as in volunteers at baseline, during voluntary hyperventilation, after an intravenous injection of lipopolysaccharide (LPS), and during norepinephrine infusion.

RESULTS

The arterial levels of CGRP, but not of VIP or ET-1, were elevated in patients with ABM, but no net cerebral flux was present. CGRP levels decreased during hyperventilation and after LPS injection. No net cerebral flux of VIP occurred in any group at any time. A cerebral efflux of ET-1, which occurred in volunteers at baseline, was neither present in volunteers after LPS injection nor in patients with ABM.

CONCLUSION

The arterial concentration of the vasodilatory peptide, CGRP, but of neither VIP nor the vasoconstrictor ET-1, is elevated in patients with ABM and sepsis. A constitutive cerebral output of ET-1 appears to be present in healthy humans, but is abolished after LPS injection.

Sensory-nerve-derived neuropeptides: possible therapeutic targets

This review examines our developing understanding of the families and activities of some of the best known sensory-nerve-derived inflammatory neuropeptides, namely substance P, calcitonin gene-related peptide and galanin. Evidence to date shows involvement of these transmitters in a wide range of systems that includes roles as inflammatory modulators. There is an increasing understanding of the mechanisms involved in the release of the peptides from sensory nerves and these are key in understanding the potential of neuropeptides in modulating inflammatory responses and may also provide novel targets for anti-inflammatory therapy. The neuropeptides released act via specific G protein coupled receptors, most of which have now been cloned. There is knowledge of selective agonists and antagonists for many subtypes within these families. The study of neuropeptides in animal models has additionally revealed pathophysiological roles that in turn have led to the development of new drugs, based on selective receptor antagonism.

Detection of stable N-terminal protachykinin A immunoreactivity in human plasma and cerebrospinal fluid

Substance P (SP) is a neuropeptide that is released from sensory nerves and several types of immune cells. It is involved in the transmission of pain and has a number of pro-inflammatory effects. Like other neuropeptides, SP is derived from a large precursor peptide, protachykinin A (PTA). Alternative splicing results in the production of four distinct PTA molecules that all contain the sequence of SP and a common N-terminal region consisting of 37 amino acids. We have developed a sandwich immunoassay using antibodies against the N-terminal part of PTA. Here we demonstrate that N-terminal PTA immunoreactivity is present in human circulation and cerebrospinal fluid (CSF). The concentration was about 90 times higher in CSF than in EDTA-plasma. Analytical reversed phase HPLC revealed that NT-PTA 1-37 is the main immunoreactivity in human circulation and CSF. Moreover, compared to the low in vitro stability of SP of less than 12 min, NT-PTA immunoreactivity is absolutely stable in EDTA-plasma and CSF for more than 48 h. As NT-PTA 1-37 is produced in stoichiometric amounts and is theoretically co-released with SP, we suggest the measurement of NT-PTA immunoreactivity as surrogate molecule for the release of bioactive SP.

Nociceptin and urotensin-II concentrations in critically ill patients with sepsis

BACKGROUND

The systemic inflammatory response to infection (sepsis) involves widespread organ dysfunction, including changes in immune modulation, cardiovascular derangements, and neural activation. Two neuropeptide/receptor systems, nociceptin/orphanin FQ (N/OFQ) which acts at the non-classical opioid receptor NOP and urotensin-II (U-II) which acts at the urotensin receptor (UT), have been implicated in neural, immune, and cardiovascular system function. In this study, we make measurements of these peptides in critically ill patients.

METHODS

Plasma samples from 21 critically ill patients with sepsis were collected over four consecutive days. Plasma N/OFQ and U-II concentrations were determined by radioimmunoassay and compared with biochemical and clinical markers of illness severity, including serum creatinine, bilirubin, platelet and white cell counts, admission APACHE II and serial SOFA scores.

RESULTS

Median (inter-quartile range) admission plasma N/OFQ concentrations in sepsis were higher in patients who died within 30 days (n=4) compared with survivors (n=17); 3.0 (2.5-5.0) vs 1.0 (1.0-2.5) pg ml(-1) (P=0.028). Plasma N/OFQ concentrations were increased in a subgroup of five patients who had undergone major gastrointestinal surgery. There were no significant changes in plasma U-II concentrations. There were no correlations between plasma U-II and N/OFQ concentrations and markers of illness severity and organ system dysfunction.

CONCLUSIONS

Plasma N/OFQ concentrations were increased in critically ill patients with sepsis who had undergone major gastrointestinal surgery and in patients who subsequently died. Further work is required to clarify the significance of plasma N/OFQ concentrations in sepsis.

Hydrogen sulfide up-regulates substance P in polymicrobial sepsis-associated lung injury

Hydrogen sulfide (H2S) has been shown to induce the activation of neurogenic inflammation especially in normal airways and urinary bladder. However, whether endogenous H2S would regulate sepsis-associated lung inflammation via substance P (SP) and its receptors remains unknown. Therefore, the aim of the study was to investigate the effect of H2S on the pulmonary level of SP in cecal ligation and puncture (CLP)-induced sepsis and its relevance to lung injury. Male Swiss mice or male preprotachykinin-A gene knockout (PPT-A-/-) mice and their wild-type (PPT-A+/+) mice were subjected to CLP-induced sepsis. DL-propargylglycine (50 mg/kg i.p.), an inhibitor of H2S formation was administered either 1 h before or 1 h after the induction of sepsis, while NaHS, an H2S donor, was given at the same time as CLP. L703606, an inhibitor of the neurokinin-1 receptor was given 30 min before CLP. DL-propargylglycine pretreatment or posttreatment significantly decreased the PPT-A gene expression and the production of SP in lung whereas administration of NaHS resulted in a further rise in the pulmonary level of SP in sepsis. PPT-A gene deletion and pretreatment with L703606 prevented H2S from aggravating lung inflammation. In addition, septic mice genetically deficient in PPT-A gene or pretreated with L703606 did not exhibit further increase in lung permeability after injection of NaHS. The present findings show for the first time that in sepsis, H2S up-regulates the generation of SP, which contributes to lung inflammation and lung injury mainly via activation of the neurokinin-1 receptor.

Negative regulation of TLR responses by the neuropeptide CGRP is mediated by the transcriptional repressor ICER

Communication between the nervous and immune systems involves the release of neuropeptides, such as calcitonin gene-related peptide (CGRP), from sensory nerves during inflammation. CGRP may inhibit the activities of both innate and adaptive immune cells, but the molecular pathways underlying this function are largely unknown. In this study, we identify CGRP as a potent inhibitor of TLR-stimulated production of inflammatory mediators, such as TNF-alpha and CCL4, by murine dendritic cells. Inhibition of TLR responses was independent of IL-10 and did not involve perturbation of canonical TLR signaling, including activation of MAPK and NF-kappaB. Instead, the inhibitory activity of CGRP was mediated by the cAMP/protein kinase A pathway leading to rapid up-regulation of the transcriptional repressor, inducible cAMP early repressor (ICER). Ectopically expressed ICER directly repressed the LPS-stimulated activity of a synthetic Tnf promoter, as well as TNF-alpha protein production driven by the endogenous promoter. Inhibition of dendritic cell gene expression by CGRP was associated with the presence of a composite cAMP response element/kappaB promoter element. In a murine model of endotoxemia, CGRP markedly attenuated serum TNF-alpha levels, and this effect was associated with the up-regulation of ICER. Together, these results establish a novel pathway for the negative regulation of TLR responses through the nervous system that critically involves induction of the transcriptional repressor ICER by the neuropeptide CGRP.

The transient receptor potential vanilloid 1 (TRPV1) receptor protects against the onset of sepsis after endotoxin

Transient potential vanilloid 1 (TRPV1) receptor is an ion channel receptor primarily localized on sensory nerves and activated by specific stimuli to initiate and amplify pain and inflammation, as typified by murine models of scald and arthritis. Little is known of the role of TRPV1 in sepsis, an infective disease associated with inflammation. Through use of a sublethal murine model of lipopolysaccharide-induced peritoneal sepsis, we provide novel evidence that genetic deletion of TRPV1 leads to an enhanced onset of various pathological components of systemic endotoxemia. Paired studies of TRPV1 knockout (KO) and wild-type mice demonstrate significantly enhanced hypotension (56+/-2% vs. 38+/-6% decrease in blood pressure, n=12), hypothermia (13+/-3% vs. 7+/-1% decrease in core temperature, n=6), and peritoneal exudate mediator levels (TNF-alpha, 0.78+/-0.2 vs. 0.38+/-0.1 ng/ml; nitrite, for NO, 35+/-10 vs. 15+/-3 microM; n=8) in TRPV1 KO mice, indicating loss of protective effect. Findings correlated with liver edema and raised plasma levels of aspartate aminotransferase in TRPV1 KO mice. These data suggest that TRPV1 may play an important regulatory role in sepsis independent of the major sensory neuropeptide substance P. The findings are relevant to developing strategies that increase the beneficial, and reduce the harmful, components of sepsis to prevent and treat this often fatal condition.

Cytochrome P450 activity mirrors nitric oxide levels in postoperative sepsis: predictive indicators of lethal outcome

BACKGROUND

The development of liver failure significantly influences prognosis during the course of major septic complications. Although the underlying cause for septic liver failure is still unclear, research using animal models has demonstrated that an increased nitric oxide (NO) synthesis compromises detoxification processes in the liver.

METHODS

In the present study, serum NO levels were measured by high-performance liquid chromatography (HPLC) and aminopyrine breath test (ABT) scores, reflecting the in vivo activity of cytochrome P450-dependent liver enzymes, were investigated in 42 patients (23 who survived sepsis [survivors]/19 patients who ultimately died of sepsis [nonsurvivors]) suffering from major septic complications after abdominal surgery. Additionally, TNF-alpha serum levels, serving as indicators for major systemic inflammation, were monitored using enzyme-linked immunosorbent assay (ELISA).

RESULTS

The increased serum NO levels that were found during sepsis correlated with the severity of the septic course. Compared with preoperative values of 42.77 +/- 5.84 mM, nitrite/nitrate levels reached 72.88 +/- 10.16 mM in early sepsis. An increased NO synthesis also was accompanied by a rise in serum TNF-alpha levels. Monitoring of liver function by ABT allowed an early differentiation between transient sepsis and sepsis with a lethal outcome (P=.006). In contrast, cytochrome P450 activity as measured by the ABT was significantly diminished in septic patients (0.45 +/- 0.02 [% dose x kgBW per (mmol CO2)-1] before sepsis onset/0.16 +/- 0.01 [% dose x kgBW per (mmol CO2)-1] in sepsis). Like the NO and TNF-alpha levels, ABT scores showed a difference between transient sepsis and sepsis with a lethal outcome. Serum NO levels were inversely correlated with ABT scores (P=.022) and positively correlated with TNF-alpha levels (P=0.015) in the late phase of sepsis. Serum TNF-alpha levels and ABT scores were inversely correlated in the early (P=.027), as well as in the late (P=.015) phases of sepsis.

CONCLUSIONS

This study supports the hypothesis that septic liver failure is linked to the induction of NO synthesis in major systemic inflammation. Therefore, the ABT provides a clinically useful tool for predicting the outcome in the early stages of sepsis. This may aid in the decision-making process when early surgical intervention is considered.

Anandamide absorption by direct hemoperfusion with polymixin B-immobilized fiber improves the prognosis and organ failure assessment score in patients with sepsis

PURPOSE

Direct hemoperfusion (DHP) with polymixin B-immobilized fiber (PMX) has been reported to be effective for patients with septic shock. The aim of this study was to clarify the mechanism of PMX-DHP effect on septic shock.

METHODS

The following parameters were measured in septic shock patients who were treated with PMX-DHP: survival rate, sepsis-related organ failure assessment (SOFA) score, acute physiology and chronic health evaluation II (APACHE-II) score, and plasma concentrations of cannabinoids [anandamide (ANA) and 2-arachidonyl glyceride (2-AG)], cytokines [interleukin (IL)-6, IL-8, IL-10], transforming growth factor beta (TGF-beta), and calcitonin gene-related peptide (CGRP)]. The primary end point was mortality from all causes at day 28 after intensive care unit (ICU) admission or discharge.

RESULTS

The survival rate of all patients at 28 days after ICU admission was 37.5% (9/24). The survival group showed significantly lower SOFA and APACHE-II scores than the nonsurvival group after PMX-DHP treatment (P = 0.008 and 0.028, respectively). The improved SOFA score group showed a better survival rate than the nonimproved SOFA score group (71.4% versus 23.5%, P = 0.028). Plasma ANA level significantly decreased after PMX-DHP treatment both in the improved SOFA score group and in the survival group. The level of 2-AG, however, showed no significant change in either group.

CONCLUSION

ANA, an intrinsic cannabinoid that induces hypotension in septic shock, is inferred to be the main mechanism of the PMX-DHP effect. Removal of ANA by PMX-DHP could be key to successful septic shock treatment.

[Indicators for early prediction of outcome in sepsis]

Sepsis is still a major cause of postoperative morbidity and mortality. Numerous biochemical indicators have been evaluated regarding their potential in predicting prognosis in sepsis. Generally, one must differentiate between indicators: those for preoperative detection of patients at risk for lethal sepsis and those for early prediction of lethal outcome of septic complications. The first include the analysis of mononuclear phagocyte interleukin (IL)-12-synthesizing capability. Reduced IL-12 levels were associated with higher lethality. Cytokine-associated gene polymorphisms such as the loss of monocyte HLA-DR expression and homozygotism for the tumor necrosis factor B2 allele have a place in preoperative risk evaluation, as they were associated with worse prognosis in sepsis. Among the most important biochemical indicators for early prediction of lethal outcome in sepsis are decreased L-selectin and elevated IL-18, IL-6, and PCT plasma concentrations. Increased nuclear factor kappaB activity in mononuclear phagocytes and elevated calcitonin gene-related protein plasma concentrations were associated with unfavourable prognosis.

Endogenous NGF regulates CGRP expression in human monocytes, and affects HLA-DR and CD86 expression and IL-10 production

Our recent results on autocrine nerve growth factor (NGF) synthesis in B lymphocytes, which directly regulates the expression and release of calcitonin gene-related peptide (CGRP), a neuropeptide known to down-regulate immune response, led us to propose an anti-inflammatory action of NGF. In the present work, we investigated whether the endogenous synthesis of NGF can regulate the expression of CGRP in other antigen-presenting cells, such as monocytes, and whether this may have a functional effect. Our data indicate that human monocytes synthesize basal levels of NGF and CGRP and that, following lipopolysaccharide (LPS) stimulation, NGF and CGRP expression are both up-regulated. When endogenous NGF is neutralized, the up-regulation of CGRP expression induced by LPS is inhibited. The expression of membrane molecules involved in T-cell activation such as human leukocyte antigen-DR (HLA-DR) and CD86 is affected by endogenous NGF, and similar effects were obtained using a CGRP(1) receptor antagonist. In addition, NGF deprivation in LPS-treated monocytes significantly decreases interleukin 10 (IL-10) synthesis. Our findings indicate that endogenous NGF synthesis has a functional role and may represent a physiologic mechanism to down-regulate major histocompatibility complex (MHC) class II and CD86 expression and alter the development of immune responses.

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.

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.

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.