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Cancer is the second leading cause of mortality worldwide. Despite recent advances in cancer treatment including immunotherapy with immune checkpoint inhibitors, new unconventional biomarkers and targets for the detection, prognosis, and treatment of cancer are still in high demand. Tumor cells are characterized by mutations that allow their unlimited growth, program their local microenvironment to support tumor growth, and spread towards distant sites. While a major focus has been on altered tumor genomes and proteomes, crucial signaling molecules such as lipids have been underappreciated. One of these molecules is the membrane phospholipid phosphatidylserine (PS) that is usually found at cytosolic surfaces of cellular membranes but can be rapidly and massively shuttled to the extracellular leaflet of the plasma membrane during apoptosis to serve as a limiting factor for immune responses. These immunosuppressive interactions are exploited by tumor cells to evade the immune system. In this review, we describe mechanisms of immune regulation in tumors, discuss if PS may constitute an inhibitory immune checkpoint, and describe current and future strategies for targeting PS to reactivate the tumor-associated immune system.
Background: Polytrauma and respiratory tract damage after thoracic trauma cause about 25% of mortality among severely injured patients. Thoracic trauma can lead to the development of severe lung complications such as acute respiratory distress syndrome, and is, therefore, of great interest for monitoring in intensive care units (ICU). In recent years, club cell protein (CC)16 with its antioxidant properties has proven to be a potential outcome-related marker. In this study, we evaluated whether CC16 constitutes as a marker of lung damage in a porcine polytrauma model.
Methods: In a 72 h ICU polytrauma pig model (thoracic trauma, tibial fracture, hemorrhagic shock, liver laceration), blood plasma samples (0, 3, 9, 24, 48, 72 h), BAL samples (72 h) and lung tissue (72 h) were collected. The trauma group (PT) was compared to a sham group. CC16 as a possible biomarker for lung injury in this model, and IL-8 concentrations as known indicator for ongoing inflammation during trauma were determined by ELISA. Histological analysis of ZO-1 and determination of total protein content were used to show barrier disruption and edema formation in lung tissue from the trauma group.
Results: Systemic CC16 levels were significantly increased early after polytrauma compared vs. sham. After 72 h, CC16 concentration was significantly increased in lung tissue as well as in BAL in PT vs. sham. Similarly, IL-8 and total protein content in BAL were significantly increased in PT vs. sham. Evaluation of ZO-1 staining showed significantly lower signal intensity for polytrauma.
Conclusion: The data confirm for the first time in a larger animal polytrauma model that lung damage was indicated by systemic and/or local CC16 response. Thus, early plasma and late BAL CC16 levels might be suitable to be used as markers of lung injury in this polytrauma model.
Background: Polytrauma and respiratory tract damage after thoracic trauma cause about 25% of mortality among severely injured patients. Thoracic trauma can lead to the development of severe lung complications such as acute respiratory distress syndrome, and is, therefore, of great interest for monitoring in intensive care units (ICU). In recent years, club cell protein (CC)16 with its antioxidant properties has proven to be a potential outcome-related marker. In this study, we evaluated whether CC16 constitutes as a marker of lung damage in a porcine polytrauma model.
Methods: In a 72 h ICU polytrauma pig model (thoracic trauma, tibial fracture, hemorrhagic shock, liver laceration), blood plasma samples (0, 3, 9, 24, 48, 72 h), BAL samples (72 h) and lung tissue (72 h) were collected. The trauma group (PT) was compared to a sham group. CC16 as a possible biomarker for lung injury in this model, and IL-8 concentrations as known indicator for ongoing inflammation during trauma were determined by ELISA. Histological analysis of ZO-1 and determination of total protein content were used to show barrier disruption and edema formation in lung tissue from the trauma group.
Results: Systemic CC16 levels were significantly increased early after polytrauma compared vs. sham. After 72 h, CC16 concentration was significantly increased in lung tissue as well as in BAL in PT vs. sham. Similarly, IL-8 and total protein content in BAL were significantly increased in PT vs. sham. Evaluation of ZO-1 staining showed significantly lower signal intensity for polytrauma.
Conclusion: The data confirm for the first time in a larger animal polytrauma model that lung damage was indicated by systemic and/or local CC16 response. Thus, early plasma and late BAL CC16 levels might be suitable to be used as markers of lung injury in this polytrauma model.
Highlights
• Suicides which occurred in a biologics trial targeting the IL-17R are revisited.
• High IL-17 levels are found in depression by the majority of reports.
• Results from studies regarding IL-17 and psychosis are mixed.
• Very few psychiatric studies investigated IL-17 signalling in suicidality.
• Potential mechanisms how IL-17 influences neuro-inflammation are described.
Abstract:
Interleukin 17 (IL-17) is a potent pro-inflammatory cytokine which plays a role in autoimmune disorders, such as psoriasis and multiple sclerosis, and is important for the defense against pathogens, particularly in the gut. However, IL-17 has recently also gained attention in association with suicidal behavior. In this review, we review the literature regarding IL-17 in psychiatric disorders and suicidality. We also take a closer look at the suicides which occurred in the clinical trial for psoriasis with brodalumab, a monoclonal antibody targeting the IL-17 receptor. Lastly, we discuss potential working mechanisms relevant to neuroinflammation and the possible involvement of IL-17.
Highligths
• Immune-inflammatory alterations might appear in subjects with ADHD.
• Blood levels of tumor necrosis factor-α might be reduced in individuals with ADHD.
• Individuals with ADHD might show elevated blood levels of interleukin-6.
Abstract
It has been observed that subclinical inflammation might be involved in the pathophysiology of attention deficit/hyperactivity disorder (ADHD). However, studies investigating peripheral blood levels of immune-inflammatory markers have provided mixed findings. We performed a systematic review and meta-analysis of studies comparing unstimulated serum or plasma levels of C-reactive protein (CRP) and cytokines in subjects with ADHD and healthy controls (the PROSPERO registration number: CRD 42021276869). Online searches covered the publication period until 30th Sep 2021 and random-effects meta-analyses were carried out. Out of 1844 publication records identified, 10 studies were included. The levels of interleukin (IL)-6 were significantly higher in studies of participants up to the age of 18 years (k = 10, g = 0.70, 95%CI: 0.10–1.30, p = 0.023) and after including those above the age of 18 years (k = 10, g = 0.71, 95%CI: 0.12–1.31, p = 0.019). In turn, the levels of tumor necrosis factor-α (TNF-α) were significantly lower in subjects with ADHD compared to healthy controls (k = 7, g = −0.16, 95%CI: −0.30 - -0.03, p = 0.020). Individual studies had a high contribution to the overall effect, since the overall effect was no longer significant after removing single studies. No significant differences were found with respect to the levels of CRP, IL-1β, IL-10 and interferon-γ. The present findings indicate that individuals with ADHD tend to show elevated levels of IL-6 and reduced levels of TNF-α. Larger and longitudinal studies recording potential confounding factors and comorbid psychopathology are needed to confirm our findings.
Highlights
• Inflammatory monocyte genes were used to stratify patients in a RCT with statins.
• One group (∼30% SSD patients) showed a distinct inflammatory monocyte signature.
• Within this “inflammatory” group, statins improved PANSS scores.
• Such changes were not observed for “inflammatory” patients receiving placebo.
• Depression scores in the “inflammatory” group improved during treatment as usual.
Abstract
Immune dysregulation has been reported in schizophrenia spectrum disorders (SSD). In the past decade, several trials using anti-inflammatory agents for treatment of SSD have been completed, with so far limited success. One such anti-inflammatory agent used is simvastatin. A recent, large-scale, randomized controlled trial with simvastatin augmentation failed to show improvement in the predefined primary outcome. However, baseline inflammatory profiles were not taken into account. Here we employed a data-driven clustering approach to investigate whether patients with an inflammatory monocyte gene signature respond better to add-on simvastatin treatment than those without such a signature, over a treatment period of 2 years. In 61 patients (60 randomized, 1:1 placebo:simvastatin) and healthy controls, a previously validated monocyte gene expression signature was assessed using quantitative polymerase chain reaction. Resulting delta cycle threshold values were used to identify patient clusters. Two major patient clusters with either up- or downregulated pro-inflammatory factors were detected. Linear mixed models showed a significant three-way interaction between the inflammatory cluster, treatment, and time for psychotic symptoms. Only patients treated with simvastatin who were in the inflammatory group, showed a consistent improvement: symptom severity gradually decreased after 3 months and reached significance after 12 and 24 months compared to baseline (p.adj<0.05). The effects were small, and overall between-group effects were not significant. Here, we show that patient stratification based on inflammatory gene expression might be useful to select appropriate treatment augmentation for patients with SSD, highlighting the need for precision medicine approaches. Our findings corroborate the results of the primary analyses, showing that in the overall group, simvastatin was not effective; however, at the individual level the treatment might make a difference.
Background: There is a need for early therapeutic interventions after traumatic brain injury (TBI) to prevent neurodegeneration. Microglia/macrophage (M/M) depletion and repopulation after treatment with colony stimulating factor 1 receptor (CSF1R) inhibitors reduces neurodegeneration. The present study investigates short- and long-term consequences after CSF1R inhibition during the early phase after TBI.
Methods: Sex-matched mice were subjected to TBI and CSF1R inhibition by PLX3397 for 5 days and sacrificed at 5 or 30 days post injury (dpi). Neurological deficits were monitored and brain tissues were examined for histo- and molecular pathological markers. RNAseq was performed with 30 dpi TBI samples.
Results: At 5 dpi, CSF1R inhibition attenuated the TBI-induced perilesional M/M increase and associated gene expressions by up to 50%. M/M attenuation did not affect structural brain damage at this time-point, impaired hematoma clearance, and had no effect on IL-1β expression. At 30 dpi, following drug discontinuation at 5 dpi and M/M repopulation, CSF1R inhibition attenuated brain tissue loss regardless of sex, as well as hippocampal atrophy and thalamic neuronal loss in male mice. Selected gene markers of brain inflammation and apoptosis were reduced in males but increased in females after early CSF1R inhibition as compared to corresponding TBI vehicle groups. Neurological outcome in behaving mice was almost not affected. RNAseq and gene set enrichment analysis (GSEA) of injured brains at 30 dpi revealed more genes associated with dendritic spines and synapse function after early CSF1R inhibition as compared to vehicle, suggesting improved neuronal maintenance and recovery. In TBI vehicle mice, GSEA showed high oxidative phosphorylation, oxidoreductase activity and ribosomal biogenesis suggesting oxidative stress and increased abundance of metabolically highly active cells. More genes associated with immune processes and phagocytosis in PLX3397 treated females vs males, suggesting sex-specific differences in response to early CSF1R inhibition after TBI.
Conclusions: M/M attenuation after CSF1R inhibition via PLX3397 during the early phase of TBI reduces long-term brain tissue loss, improves neuronal maintenance and fosters synapse recovery. Overall effects were not sex-specific but there is evidence that male mice benefit more than female mice.
Objective: The NADPH oxidase Nox4 is an important source of H2O2. Nox4-derived H2O2 limits vascular inflammation and promotes smooth muscle differentiation. On this basis, the role of Nox4 for restenosis development was determined in the mouse carotid artery injury model. Methods and results: Genetic deletion of Nox4 by a tamoxifen-activated Cre-Lox-system did not impact on neointima formation in the carotid artery wire injury model. To understand this unexpected finding, time-resolved single-cell RNA-sequencing (scRNAseq) from injured carotid arteries of control mice and massive-analysis-of-cDNA-ends (MACE)-RNAseq from the neointima harvested by laser capture microdissection of control and Nox4 knockout mice was performed. This revealed that resting smooth muscle cells (SMCs) and fibroblasts exhibit high Nox4 expression, but that the proliferating de-differentiated SMCs, which give rise to the neointima, have low Nox4 expression. In line with this, the first weeks after injury, gene expression was unchanged between the carotid artery neointimas of control and Nox4 knockout mice. Conclusion: Upon vascular injury, Nox4 expression is transiently lost in the cells which comprise the neointima. NADPH oxidase 4 therefore does not interfere with restenosis development after wire-induced vascular injury.
Aims: Patients with cardiovascular comorbidities have a significantly increased risk for a critical course of COVID-19. As the SARS-CoV2 virus enters cells via the angiotensin-converting enzyme receptor II (ACE2), drugs which interact with the renin angiotensin aldosterone system (RAAS) were suspected to influence disease severity.
Methods and results: We analyzed 1946 consecutive patients with cardiovascular comorbidities or hypertension enrolled in one of the largest European COVID-19 registries, the Lean European Open Survey on SARS-CoV-2 (LEOSS) registry. Here, we show that angiotensin II receptor blocker intake is associated with decreased mortality in patients with COVID-19 [OR 0.75 (95% CI 0,59–0.96; p = 0.013)]. This effect was mainly driven by patients, who presented in an early phase of COVID-19 at baseline [OR 0,64 (95% CI 0,43–0,96; p = 0.029)]. Kaplan-Meier analysis revealed a significantly lower incidence of death in patients on an angiotensin receptor blocker (ARB) (n = 33/318;10,4%) compared to patients using an angiotensin-converting enzyme inhibitor (ACEi) (n = 60/348;17,2%) or patients who received neither an ACE-inhibitor nor an ARB at baseline in the uncomplicated phase (n = 90/466; 19,3%; p<0.034). Patients taking an ARB were significantly less frequently reaching the mortality predicting threshold for leukocytes (p<0.001), neutrophils (p = 0.002) and the inflammatory markers CRP (p = 0.021), procalcitonin (p = 0.001) and IL-6 (p = 0.049). ACE2 expression levels in human lung samples were not altered in patients taking RAAS modulators.
Conclusion: These data suggest a beneficial effect of ARBs on disease severity in patients with cardiovascular comorbidities and COVID-19, which is linked to dampened systemic inflammatory activity.
Endocannabinoids are important lipid-signaling mediators. Both protective and deleterious effects of endocannabinoids in the cardiovascular system have been reported but the mechanistic basis for these contradicting observations is unclear. We set out to identify anti-inflammatory mechanisms of endocannabinoids in the murine aorta and in human vascular smooth muscle cells (hVSMC). In response to combined stimulation with cytokines, IL-1β and TNFα, the murine aorta released several endocannabinoids, with anandamide (AEA) levels being the most significantly increased. AEA pretreatment had profound effects on cytokine-induced gene expression in hVSMC and murine aorta. As revealed by RNA-Seq analysis, the induction of a subset of 21 inflammatory target genes, including the important cytokine CCL2 was blocked by AEA. This effect was not mediated through AEA-dependent interference of the AP-1 or NF-κB pathways but rather through an epigenetic mechanism. In the presence of AEA, ATAC-Seq analysis and chromatin-immunoprecipitations revealed that CCL2 induction was blocked due to increased levels of H3K27me3 and a decrease of H3K27ac leading to compacted chromatin structure in the CCL2 promoter. These effects were mediated by recruitment of HDAC4 and the nuclear corepressor NCoR1 to the CCL2 promoter. This study therefore establishes a novel anti-inflammatory mechanism for the endogenous endocannabinoid AEA in vascular smooth muscle cells. Furthermore, this work provides a link between endogenous endocannabinoid signaling and epigenetic regulation.
Aims: SARS-CoV-2 infection is associated with adverse outcomes in patients with cardiovascular disease. Here, we analyzed whether specific biomarkers predict the clinical course of COVID-19 in patients with cardiovascular comorbidities. Methods and results: We enrolled 2147 patients with SARS-CoV-2 infection which were included in the Lean European Open Survey on SARS-CoV‑2 (LEOSS)-registry from March to June 2020. Clinical data and laboratory values were collected and compared between patients with and without cardiovascular comorbidities in different clinical stages of the disease. Predictors for mortality were calculated using multivariate regression analysis. We show that patients with cardiovascular comorbidities display significantly higher markers of myocardial injury and thrombo-inflammatory activation already in the uncomplicated phase of COVID-19. In multivariate analysis, elevated levels of troponin [OR 1.54; (95% CI 1.22–1.96), p < 0.001)], IL-6 [OR 1.69 (95% CI 1.26–2.27), p < 0.013)], and CRP [OR 1.32; (95% CI 1.1–1.58), p < 0.003)] were predictors of mortality in patients with COVID-19. Conclusion: Patients with cardiovascular comorbidities show elevated markers of thrombo-inflammatory activation and myocardial injury, which predict mortality, already in the uncomplicated phase of COVID-19. Starting targeted anti-inflammatory therapy and aggressive anticoagulation already in the uncomplicated phase of the disease might improve outcomes after SARS-CoV-2 infection in patients with cardiovascular comorbidities.
Aims: Systemic inflammatory response, identified by increased total leucocyte counts, was shown to be a strong predictor of mortality after transcatheter aortic valve implantation (TAVI). Yet the mechanisms of inflammation-associated poor outcome after TAVI are unclear. Therefore, the present study aimed at investigating individual inflammatory signatures and functional heterogeneity of circulating myeloid and T-lymphocyte subsets and their impact on 1 year survival in a single-centre cohort of patients with severe aortic stenosis undergoing TAVI. Methods and results: One hundred twenty-nine consecutive patients with severe symptomatic aortic stenosis admitted for transfemoral TAVI were included. Blood samples were obtained at baseline, immediately after, and 24 h and 3 days after TAVI, and these were analysed for inflammatory and cardiac biomarkers. Myeloid and T-lymphocyte subsets were measured using flow cytometry. The inflammatory parameters were first analysed as continuous variables; and in case of association with outcome and area under receiver operating characteristic (ROC) curve (AUC) ≥ 0.6, the values were dichotomized using optimal cut-off points. Several baseline inflammatory parameters, including high-sensitivity C-reactive protein (hsCRP; HR = 1.37, 95% CI: 1.15–1.63; P < 0.0001) and IL-6 (HR = 1.02, 95% CI: 1.01–1.03; P = 0.003), lower counts of Th2 (HR = 0.95, 95% CI: 0.91–0.99; P = 0.009), and increased percentages of Th17 cells (HR = 1.19, 95% CI: 1.02–1.38; P = 0.024) were associated with 12 month all-cause mortality. Among postprocedural parameters, only increased post-TAVI counts of non-classical monocytes immediately after TAVI were predictive of outcome (HR = 1.03, 95% CI: 1.01–1.05; P = 0.003). The occurrence of SIRS criteria within 48 h post-TAVI showed no significant association with 12 month mortality (HR = 0.57, 95% CI: 0.13–2.43, P = 0.45). In multivariate analysis of discrete or dichotomized clinical and inflammatory variables, the presence of diabetes mellitus (HR = 3.50; 95% CI: 1.42–8.62; P = 0.006), low left ventricular (LV) ejection fraction (HR = 3.16; 95% CI: 1.35–7.39; P = 0.008), increased baseline hsCRP (HR = 5.22; 95% CI: 2.09–13.01; P < 0.0001), and low baseline Th2 cell counts (HR = 8.83; 95% CI: 3.02–25.80) were significant predictors of death. The prognostic value of the linear prediction score calculated of these parameters was superior to the Society of Thoracic Surgeons score (AUC: 0.88; 95% CI: 0.78–0.99 vs. 0.75; 95% CI: 0.64–0.86, respectively; P = 0.036). Finally, when analysing LV remodelling outcomes, ROC curve analysis revealed that low numbers of Tregs (P = 0.017; AUC: 0.69) and increased Th17/Treg ratio (P = 0.012; AUC: 0.70) were predictive of adverse remodelling after TAVI. Conclusions: Our findings demonstrate an association of specific pre-existing inflammatory phenotypes with increased mortality and adverse LV remodelling after TAVI. Distinct monocyte and T-cell signatures might provide additive biomarkers to improve pre-procedural risk stratification in patients referred to TAVI for severe aortic stenosis.
Aims: Long non-coding RNAs (lncRNAs) have been shown to regulate numerous processes in the human genome, but the function of these transcripts in vascular aging is largely unknown. We aim to characterize the expression of lncRNAs in endothelial aging and analyse the function of the highly conserved lncRNA H19.
Methods and results: H19 was downregulated in endothelium of aged mice. In human, atherosclerotic plaques H19 was mainly expressed by endothelial cells and H19 was significantly reduced in comparison to healthy carotid artery biopsies. Loss of H19 led to an upregulation of p16 and p21, reduced proliferation and increased senescence in vitro. Depletion of H19 in aortic rings of young mice inhibited sprouting capacity. We generated endothelial-specific inducible H19 deficient mice (H19iEC-KO), resulting in increased systolic blood pressure compared with control littermates (Ctrl). These H19iEC-KO and Ctrl mice were subjected to hindlimb ischaemia, which showed reduced capillary density in H19iEC-KO mice. Mechanistically, exon array analysis revealed an involvement of H19 in IL-6 signalling. Accordingly, intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 were upregulated upon H19 depletion. A luciferase reporter screen for differential transcription factor activity revealed STAT3 as being induced upon H19 depletion and repressed after H19 overexpression. Furthermore, depletion of H19 increased the phosphorylation of STAT3 at TYR705 and pharmacological inhibition of STAT3 activation abolished the effects of H19 silencing on p21 and vascular cell adhesion molecule 1 expression as well as proliferation.
Conclusion: These data reveal a pivotal role for the lncRNA H19 in controlling endothelial cell aging.
IL-22 is an immunoregulatory cytokine displaying pathological functions in models of autoimmunity like experimental psoriasis. Understanding molecular mechanisms driving IL-22, together with knowledge on the capacity of current immunosuppressive drugs to target this process, may open an avenue to novel therapeutic options. Here, we sought to characterize regulation of human IL22 gene expression with focus on the established model of Jurkat T cells. Moreover, effects of the prototypic immunosuppressant cyclosporin A (CsA) were investigated. We report that IL-22 induction by TPA/A23187 (T/A) or αCD3 is inhibited by CsA or related FK506. Similar data were obtained with peripheral blood mononuclear cells or purified CD3(+) T cells. IL22 promoter analysis (-1074 to +156 bp) revealed a role of an NF-AT (-95/-91 nt) and a CREB (-194/-190 nt) binding site for gene induction. Indeed, binding of CREB and NF-ATc2, but not c-Rel, under the influence of T/A to those elements could be proven by ChIP. Because CsA has the capability to impair IκB kinase (IKK) complex activation, the IKKα/β inhibitor IKKVII was evaluated. IKKVII likewise reduced IL-22 induction in Jurkat cells and peripheral blood mononuclear cells. Interestingly, transfection of Jurkat cells with siRNA directed against IKKα impaired IL22 gene expression. Data presented suggest that NF-AT, CREB, and IKKα contribute to rapid IL22 gene induction. In particular the crucial role of NF-AT detected herein may form the basis of direct action of CsA on IL-22 expression by T cells, which may contribute to therapeutic efficacy of the drug in autoimmunity.
Peroxisome proliferator-activated receptor γ (PPARγ) gained considerable interest as a therapeutic target during chronic inflammatory diseases. Remarkably, the pathogenesis of diseases such as multiple sclerosis or Alzheimer is associated with impaired PPARγ expression. Considering that regulation of PPARγ expression during inflammation is largely unknown, we were interested in elucidating underlying mechanisms. To this end, we initiated an inflammatory response by exposing primary human macrophages to lipopolysaccharide (LPS) and observed a rapid decline of PPARγ1 expression. Because promoter activities were not affected by LPS, we focused on mRNA stability and noticed a decreased mRNA half-life. As RNA stability is often regulated via 3′-untranslated regions (UTRs), we analyzed the impact of the PPARγ-3′-UTR by reporter assays using specific constructs. LPS significantly reduced luciferase activity of the pGL3-PPARγ-3′-UTR, suggesting that PPARγ1 mRNA is destabilized. Deletion or mutation of a potential microRNA-27a/b (miR-27a/b) binding site within the 3′-UTR restored luciferase activity. Moreover, inhibition of miR-27b, which was induced upon LPS exposure, partially reversed PPARγ1 mRNA decay, whereas miR-27b overexpression decreased PPARγ1 mRNA content. In addition, LPS further reduced this decay. The functional relevance of miR-27b-dependent PPARγ1 decrease was proven by inhibition or overexpression of miR-27b, which affected LPS-induced expression of the pro-inflammatory cytokines tumor necrosis factor α (TNFα) and interleukin (IL)-6. We provide evidence that LPS-induced miR-27b contributes to destabilization of PPARγ1 mRNA. Understanding molecular mechanisms decreasing PPARγ might help to better appreciate inflammatory diseases.
Die Entzündung ist eine Folge von Reaktionen mit der Zielsetzung, die Ausbreitung einer Gewebeschädigung, oder eines Infektionserregers einzudämmen. Zelluläre und humorale Mechanismen interagieren dabei in einem komplexen Netzwerk. In diesem Übersichtsbeitrag zeigen wir die wichtigsten Wege des inflammatorischen Reaktionsgeschehens auf und diskutieren die Bedeutung von Laboratoriumsuntersuchungen für die Diagnostik und das Monitoring von Entzündungen.
Wesentliche Schritte im Ablauf der Entzündungsreaktion sind
- die Synthese von Prostaglandinen aus Arachidonsäure, die durch Phospholipasen A2 (PLA2)-katalysierte Hydrolyse aus Membranphospholipiden gebildet wird;
- Interaktionen zwischen Gefäßendothel und Leukozyten, die Leukozytenextravasation und die Freisetzung freier Sauerstoffradikale und von Elastase im Gewebe;
- die Bildung inflammatorischer Cytokine, ihr Effekt auf Entzündungszellen und ihre systemische Wirkung auf Organe;
- die Synthese von Akute-Phase-Proteinen, deren Plasmakonzentration bei Entzündung als Antwort auf eine Vielfalt von Schädigungen ansteigt.
Zur Diagnostik und Verlaufsbeurteilung entzündlicher Krankheiten hat die Bestimmung des C-reaktiven Proteins den höchsten Stellenwert. Die Elastase hat nur eine begrenzte Bedeutung. Die Bestimmung von PLA2, der 'inflammatorischen Cytokine TNFa, IL-1, IL-6 und des s!L-2R als generelle Entzündungsmarker kann in der Routinediagnostik noch nicht empfohlen werden. Eingehende klinische Untersuchungen zur diagnostischen Bedeutung müssen noch abgewartet werden.