The long pentraxin 3 (PTX3): a novel prognostic inflammatory marker for mortality in acute chest pain

Pentraxin-3 in the Spinal Dorsal Horn Upregulates Nectin-1 Expression in Neuropathic Pain after Spinal Nerve Damage in Male Mice

Purpose: Neuropathic pain often originates from nerve injury or diseases of the somatosensory nervous system. However, its specific pathogenesis remains unclear. The requirement for excitatory synaptic plasticity in pain-related syndromes has been demonstrated. A recent study reported that pentraxin-3 is important in glutamatergic synaptic formation and function. Meanwhile, nectin-1 mediates synaptogenesis in neurological disorders. The present study aimed to evaluate whether pentraxin-3 and nectin-1 modulate spinal nerve damage-related neuropathic pain in male mice. Methods: L₄ spinal nerve ligation (SNL) in male mice was performed to induce experimental neuropathic pain. Mechanical allodynia and heat hyperalgesia following SNL were based on paw withdrawal (PW) threshold and PW latency, respectively. Spinal pentraxin-3 levels and nectin-1 expression following SNL were examined. Pentraxin-3 and nectin-1 knockdown models were established by the shRNA method. These models were used with a recombinant pentraxin-3 cell model to investigate the underlying mechanisms of SNL. Results: The SNL operation generated persistent decreases in mechanical PW threshold and thermal PW latency, with subsequent long-lasting elevations in spinal pentraxin-3 and nectin-1 expression levels. Pentraxin-3 knockdown reduced SNL-associated neuropathic pain behaviors as well as nectin-1 amounts in the spinal dorsal horn. Nectin-1 deficiency impaired mechanical allodynia and thermal hyperalgesia following spinal nerve injury. The application of recombinant pentraxin-3 in the spinal cord triggered an acute nociception phenotype and induced spinal overexpression of nectin-1. The intrathecal knockdown of nectin-1 prevented exogenous pentraxin-3-evoked pain hypersensitivity. Conclusions: The findings suggest spinal pentraxin-3 is required for SNL-triggered neuropathic pain via nectin-1 upregulation in male mice.

Higher Plasma Pentraxin-3 Level Predicts Adverse Clinical Outcomes in Patients With Coronary Artery Disease: A Meta-Analysis of Cohort Studies

Background: Association between plasma pentraxin-3 (PTX-3) and clinical outcomes in patients with coronary artery disease (CAD) remains not fully determined. An updated meta-analysis of cohort studies was performed to systematically evaluate the association.

Methods: Cohort studies evaluating the association between plasma PTX-3 and adverse outcomes [mortality and major adverse cardiovascular events (MACEs)] in adults with CAD were identified by systematic search of PubMed, Embase, and Web of Science databases. Only studies with multivariate analysis were included. A random-effects model incorporating the potential intrastudy heterogeneity was used for the meta-analysis.

Results: A total of 16 studies including 11,007 patients were included. Pooled results showed that patients with highest level of PTX-3 were independently associated with higher risk of mortality [adjusted risk ratio (RR): 2.09, 95% CI: 1.60 to 2.74, p < 0.001; I² = 50%] and MACEs (adjusted RR: 1.80, 95% CI: 1.43 to 2.28, p < 0.001; I² = 49%). Subgroup analyses showed that the associations between PTX-3 and poor prognosis in CAD were consistent in patients with ST-segment elevation myocardial infraction, non-ST-segment elevation acute coronary syndrome, and stable CAD (p < 0.05 for each subgroup). Besides, the association between PTX-3 and increased incidence of mortality and MACEs were consistent in short-term (within 1 year) and long-term (over 1 year) studies and in studies with or without adjustment of C-reactive protein (CRP) (p < 0.05 for each subgroup).

Conclusion: Higher plasma PTX-3 is associated with poor prognosis in patients with CAD, which may be independent of the CAD subtype, follow-up durations, and adjustment of CRP.

Pentraxin 3 concentration is associated with poor outcomes in patients with coronary artery disease: a systematic review and dose-response meta-analysis

BACKGROUND

The amount of plasma pentraxin 3 (PTX3) is gradually being considered as a novel biomarker in forecasting poor clinical outcomes in patients with coronary artery disease (CAD). However, very little is known about the connection between PTX3 and CAD. This dose-response meta-analysis was carried out to quantify the relationship between circulating PTX3 concentration and CAD prognosis.

METHODS

A systematic literature search was conducted using PubMed, EuropePMC, ProQuest, EBSCOhost, SCOPUS, Cochrane Library, and Google Scholar up until April 2021. The primary outcome of this study consisted of mortality and major adverse cardiovascular events (MACEs).

RESULTS

The current meta-analysis comprised 15 studies with a total of 11.365 participants. High circulating PTX3 concentrations were associated with a higher risk of composite poor outcomes as compared to low circulating PTX3 concentrations (OR: 1.36 [1.18, 1.54], p < 0.001; I² = 86.69%, P_{heterogeneity}<0.001), mortality (OR: 1.43 [1.15, 1.71], p < 0.001; I² = 87.58%, P_{heterogeneity}<0.001), and MACEs (OR: 1.28 [1.08, 1.48], p < 0.001; I² = 35.86%, P_{heterogeneity} = 0.08) in patients with CAD. Consistent results were obtained during meta-regression analyses and in all examined subgroups. The adjusted odds ratios (aORs) for composite poor outcomes increased by 32% per 1 ng/mL increment (OR: 1.32 [1.21, 1.43]) in line with the dose-response meta-analysis.

CONCLUSION

A significant positive dose-dependent association between circulating PTX3 concentration and the risk of poor outcomes in patients with CAD was found in this dose-response meta-analysis.

Pentraxin-3 vs C-reactive protein and other prognostic biomarkers in acute coronary syndrome: A substudy of the Platelet Inhibition and Patients Outcomes (PLATO) trial

AIMS

We investigated the dynamics, associations with patient characteristics, other biomarkers, and clinical outcomes of pentraxin 3 in acute coronary syndrome.

METHODS AND RESULTS

In multivariate analyses, pentraxin 3 measured in 5154 patients randomised in the Platelet Inhibition and Patients Outcomes (PLATO) trial (NCT00391872) was compared with leukocytes, high-sensitivity C-reactive protein, interleukin-6, cystatin C, N-terminal prohormone brain natriuretic peptide, high-sensitivity troponin T and growth differentiation factor 15 concerning prediction of clinical outcome. Pentraxin 3 peaked earlier than high-sensitivity C-reactive protein and was more strongly correlated with N-terminal prohormone brain natriuretic peptide and high-sensitivity troponin T than with high-sensitivity C-reactive protein. The frequency of cardiovascular death, spontaneous myocardial infarction or stroke by quartiles of pentraxin 3 at admission was 6.1%, 7.3%, 9.7% and 10.7%, respectively (p<0.0001). The hazard ratio per 50% increase of pentraxin 3 was 1.13 (95% confidence interval: 1.07-1.19), p<0.0001. This association remained significant after stepwise adjustments for leukocytes/high-sensitivity C-reactive protein (1.09 (1.02-1.15)), p=0.009, interleukin-6 (1.07 (1.01-1.14)), p=0.026, and cystatin C (1.07 (1.00-1.13)), p=0.044, but not after adjustment for N-terminal prohormone brain natriuretic peptide, high-sensitivity troponin T and growth differentiation factor 15. Admission pentraxin 3 was also associated with several of the individual endpoint components (cardiovascular death/spontaneous myocardial infarction; p=0.008, cardiovascular death; p=0.026, and spontaneous myocardial infarction; p=0.017), but not with stroke. Pentraxin 3 measured in the chronic phase (i.e. at one month) was still predictive of the composite endpoint in univariate analysis (1.12 (1.04-1.20) per 50% increase) p=0.0024, but not after adjustment for the other biomarkers.

CONCLUSION

Admission level of pentraxin 3 is a modestly stronger predictor than high-sensitivity C-reactive protein and interleukin-6, but not than N-terminal prohormone brain natriuretic peptide or high-sensitivity troponin T, concerning cardiovascular outcome in acute coronary syndrome. Pentraxin 3 is more strongly correlated with N-terminal prohormone brain natriuretic peptide and high-sensitivity troponin T than with high-sensitivity C-reactive protein.

Pentraxin-3 in coronary artery disease: A meta-analysis

AIMS

Studies on the prognostic significance of circulating pentraxin-3 level in patients with coronary artery disease (CAD) have yielded conflicting results. The aim of this meta-analysis was to evaluate the prognostic value of circulating pentraxin-3 level in CAD patients.

MATERIALS/METHODS

We made a systematic literature search in Pubmed, Embae, CNKI, Wanfang, and VIP database from their inception to January 10, 2019 for prospective cohort studies that investigated the association between pentraxin-3 level and adverse outcomes in patients with CAD. The outcome measures were all-cause mortality, cardiac death, and cardiac events (cardiac death, nonfatal myocardial infarction, heart failure or coronary revascularization). Multivariable-adjusted risk ratio (RR) with 95% confidence intervals (CI) was pooled for the highest versus the lowest pentraxin-3 group to summarize the predictive value.

RESULTS

Nine studies were included, enrolling 5,174 CAD patients. Overall, CAD patients with the highest pentraxin-3 level had an increased risk of all-cause mortality (RR 1.81; 95% CI 1.43-2.28), cardiac death (RR 1.77; 95% CI 1.38-2.26), and cardiac events (RR 1.61; 95% CI 1.16-2.25). However, elevated pentraxin-3 level appeared to not significantly increase the risk of cardiac events (RR 1.63; 95% CI 0.71-3.72) in stable CAD subgroup.

CONCLUSIONS

In CAD patients, elevated circulating pentraxin-3 level is possibly an independent predictor of all-cause mortality, cardiac death, and cardiac events. However, interpretation of these findings should be with caution due to the small number of studies analyzed.

PTX3: A Potential Biomarker in Thyroid Associated Ophthalmopathy

Background

Thyroid associated ophthalmopathy (TAO) is an autoimmune disease, which involves inflammation and tissue remodeling. Pentraxin-3 (PTX3) is a component of innate immune system and recently implicated in autoimmunity. This observation may indicate that PTX3 participates in the inflammatory process of TAO.

Methods

All studies were performed on TAO patients and healthy controls (45: 28 in total). RNA-seq was used to detect differential gene expression of orbital adipose-connective tissue. Quantitative PCR was performed to verify the results. PTX3 protein in orbital adipose-connective tissues was visualized by immunohistochemistry (IHC). PTX3 concentration in serum was determined by enzyme-linked immunosorbent assay (ELISA).

Results

RNA-seq showed 1.86-log⁡2FC higher PTX3 expression in the orbital adipose-connective tissues from TAO group than controls (FDR = 0.0059). qPCR confirmed the difference (5.59-fold increase, p = 0.0012). The presence of PTX3 protein was demonstrated. Orbital adipose tissue from healthy controls showed weak staining for PTX3 while tissue from TAO group was strongly positive. Serum PTX3 concentration was significantly elevated in patients when compared to the control group (1.9-fold increase; p < 0.0001).

Conclusions

Patients with TAO showed increased presence of PTX3 in orbital tissue and serum, which may suggest a potential relationship of PTX3 and TAO.

The prognostic utility of dihomo-gamma-linolenic acid (DGLA) in patients with acute coronary heart disease

BACKGROUND

We previously investigated the prognostic utility of red blood cell (RBC) n-3 fatty acids (FAs) in survivors of an acute myocardial syndrome (ACS) but found no relationship with all-cause mortality and cardiac death or MI after two years. Here we extend our follow-up to 7years, focusing on the potential predictive power of RBC n-6 FAs.

METHODS

We included 398 ACS patients presenting with increased troponin-T (TnT) levels for whom baseline RBC FA data were available. Cox regression analysis was used to relate the risk of future events to RBC n-6 FA levels, both continuously and by quartile.

RESULTS

At 7-year follow-up, 183 (46.0%) had died, 128 (32.2%) had experienced another MI and 24 (6.0%) had had a stroke. Death or MI occurred in 227 patients (57.0%); and death, MI or stroke in 235 patients (59.0%). In a multivariable Cox regression model for total death, the hazard ratio (HR) in the highest as compared to the lowest quartile of dihomo-γ-linolenic acid (DGLA) was 0.55 [95% confidence interval (CI), 0.35-0.88, p=0.012, for death or MI [HR 0.62 (95% CI, 0.41-0.94), p=0.025], and for the fully combined endpoint [HR 0.57 (95% CI, 0.38-0.86), p=0.006]. Similar results were found in the per 1-SD analysis. No other RBC n-6 FAs significantly predicted these outcomes in multivariable models.

CONCLUSION

RBC DGLA levels had significant independent prognostic value in post-ACS patients. These findings need confirmation, and the possible biochemical pathways by which higher DGLA membrane levels may be cardioprotective should be explored.

Featured Article: Depletion of HDL3 high density lipoprotein and altered functionality of HDL2 in blood from sickle cell patients

In sickle cell disease (SCD), alterations of cholesterol metabolism is in part related to abnormal levels and activity of plasma proteins such as lecithin cholesterol acyltransferase (LCAT), and apolipoprotein A-I (ApoA-I). In addition, the size distribution of ApoA-I high density lipoproteins (HDL) differs from normal blood. The ratio of the amount of HDL₂ particle relative to the smaller higher density pre-β HDL (HDL₃) particle was shifted toward HDL₂. This lipoprotein imbalance is exacerbated during acute vaso-occlusive episodes (VOE) as the relative levels of HDL₃ decrease. HDL₃ deficiency in SCD plasma was found to relate to a slower ApoA-I exchange rate, which suggests an impaired ABCA1-mediated cholesterol efflux in SCD. HDL₂ isolated from SCD plasma displayed an antioxidant capacity normally associated with HDL₃, providing evidence for a change in function of HDL₂ in SCD as compared to HDL₂ in normal plasma. Although SCD plasma is depleted in HDL₃, this altered capacity of HDL₂ could account for the lack of difference in pro-inflammatory HDL levels in SCD as compared to normal. Exposure of human umbilical vein endothelial cells to HDL₂ isolated from SCD plasma resulted in higher mRNA levels of the acute phase protein long pentraxin 3 (PTX3) as compared to incubation with HDL₂ from control plasma. Addition of the heme-scavenger hemopexin protein prevented increased expression of PTX3 in sickle HDL₂-treated cells. These findings suggest that ApoA-I lipoprotein composition and functions are altered in SCD plasma, and that whole blood transfusion may be considered as a blood replacement therapy in SCD. Impact statement Our study adds to the growing evidence that the dysfunctional red blood cell (RBC) in sickle cell disease (SCD) affects the plasma environment, which contributes significantly in the vasculopathy that defines the disease. Remodeling of anti-inflammatory high density lipoprotein (HDL) to pro-inflammatory entities can occur during the acute phase response. SCD plasma is depleted of the pre-β particle (HDL₃), which is essential for stimulation of reverse cholesterol from macrophages, and the function of the larger HDL₂ particle is altered. These dysfunctions are exacerbated during vaso-occlusive episodes. Interaction of lipoproteins with endothelium increases formation of inflammatory mediators, a process counteracted by the heme-scavenger hemopexin. This links hemolysis to lipoprotein-mediated inflammation in SCD, and hemopexin treatment could be considered. The use of RBC concentrates in transfusion therapy of SCD patients underestimates the importance of the dysfunctional plasma compartment, and transfusion of whole blood or plasma may be warranted.

Borderline Values of Troponin-T and High Sensitivity C-Reactive Protein Did Not Predict 2-Year Mortality in TnT Positive Chest-Pain Patients, Whereas Brain Natriuretic Peptide Did

Background

Troponin-T (TnT), high-sensitive C-reactive protein (hsCRP), and Brain Natriuretic Peptide (BNP) have been shown to be independent prognostic indicators of total and cardiac death during short- and long-term follow-up.

Methods

We investigated prospectively the prognostic value of admission samples of TnT, hsCRP, and BNP in 871 chest-pain patients from South-Western Norway and 982 patients from Northern Argentina, based on a similar protocol and database setup. Follow-up was 2 years for the pooled population. The prognostic value of the selected biomarkers was investigated in quartiles of 239 patients with TnT values greater than 0.01 and up to and including 0.1 ng/mL, with continuous TnT as a potential confounder.

Results

After 24 months, 69 patients had died, of whom 38 died from cardiac causes. In the selected range of TnT, this biomarker was not significantly different between patients who died and survived (mean 0.0452 and 0.0457, p = 0.887). The BNP levels were significantly higher among patients dying than in long-term survivors [340 (142–656) versus 157 (58–367) pg/mL (median, 25 and 75% percentiles), p < 0.001]. In a multivariable Cox regression model for death within 2 years, the hazard ratio (HR) for BNP in the highest quartile (Q4) as compared to the lowest (Q1) was significantly related to total mortality [HR 2.84 (95% confidence interval (CI), 1.13–7.17)], p = 0.027, in addition to age (p ≤ 0.001) and hypercholesterolemia (p = 0.043). For cardiac death, the HR for BNP was 5.18 (95% CI, 1.06–25.3), p = 0.042. Several other variables (age, congestive heart failure, ST elevation myocardial infarction, and study country) were also significantly related to cardiac death. In a multivariable Cox regression model, hsCRP rendered no significant prognostic information for all-cause mortality (p = 0.089) or for cardiac mortality (p = 0.524).

Conclusion

In patients with borderline TnT values (greater than 0.01 and up to and including 0.1 ng/mL), this biomarker as well as hsCRP did not render prognostic information, whereas BNP was found to be a strong prognostic indicator of 2-year total and cardiac mortality.

Long-term prognostic utility of pentraxin 3 and D-dimer as compared to high-sensitivity C-reactive protein and B-type natriuretic peptide in suspected acute coronary syndrome

BACKGROUND

Vascular inflammation plays a key role in the development of atherosclerosis and acute coronary syndrome (ACS), and pentraxin 3 (PTX3) is one of several novel, promising markers of inflammation. In addition, D-dimer might serve as a marker of thrombogenesis and a hypercoagulable state following plaque rupture. The present study assesses the prognostic utility of these two biomarkers as compared to high-sensitivity C-reactive protein (hsCRP) and B-type natriuretic peptide (BNP), in addition to conventional clinical risk factors for coronary heart disease in patients with suspected ACS.

METHODS

Chest pain patients with suspected ACS (n = 871) were consecutively included in a prospective, observational study with a follow-up time of 84 months.

RESULTS

At 7-year follow-up, 332 patients had died and 203 had suffered an adverse troponin T-positive, non-fatal cardiac event. In the multivariate analysis, levels of PTX3 above 5.88 ng/mL (median) and D-dimer above 436 µg/L (lower limit upper quartile) independently predicted mortality (HR 1.60 [95% CI 1.10-2.33]; p = 0.014 and HR 1.83 [95% CI 1.20-2.78]; p = 0.005, respectively). Also, BNP levels above 310.75 pg/mL (lower limit upper quartile) (HR 2.16 [95% CI 1.37-3.42]; p = 0.001), but not hsCRP, independently predicted mortality. Only hsCRP and BNP also predicted future myocardial infarction (HR 1.59 [95% CI 1.05-2.40]; p = 0.029 and HR 1.91 [95% CI 1.10-3.31]; p = 0.021, respectively).

CONCLUSION

High levels of PTX3, D-dimer and BNP were found to be independent, long-term predictors of all-cause mortality in chest pain patients with a suspected ACS. hsCRP and BNP also predicted future myocardial infarction.

Pentraxin-3 level at admission is a strong predictor of short-term mortality in a community-based hospital setting

BACKGROUND

The pattern recognition molecule pentraxin-3 (PTX3) is a novel potential marker of prognosis, as elevated levels are associated with both disease severity and mortality in patients with a wide range of conditions. However, the usefulness of PTX3 as a prognostic biomarker in a general hospital setting is unknown.

PATIENTS AND METHODS

The study cohort consisted of 1326 unselected, consecutive patients (age >40 years) admitted to a community hospital in Copenhagen, Denmark. Patients were followed until death or for a median of 11.5 years after admission. The main outcome measure was all-cause mortality. Serum samples collected from patients at admission and from 192 healthy control subjects were quantified for PTX3 level by enzyme-linked immunosorbent assay.

RESULTS

PTX3 was elevated in patients (median 3.7 ng mL(-1) , range 0.5-209.8) compared with healthy nonhospitalized subjects (median 3.5 ng mL(-1) , range 0.0-8.3; P = 0.0003). Elevated PTX3 levels, defined as above the 95th percentile of the concentration in healthy subjects, were associated with increased overall mortality during the study (P < 0.0001). This increase in mortality was greatest in the short term, with an unadjusted hazard ratio (HR) of 6.4 [95% confidence interval (CI) 3.8-11.0] at 28 days after admission, compared to 1.7 (95% CI 1.4-2.0) at the end of follow-up. These results were still significant after adjustment for age, gender and glomerular filtration rate: adjusted HR of 5.0 (95% CI 2.9-8.8) and 1.4 (95% CI 1.2-1.8), respectively.

CONCLUSION

These results suggest that PTX3 could be a widely applicable marker of short-term mortality in hospitalized patients and may be useful in the initial risk stratification.

Associations between pentraxin 3 and severity of coronary artery disease

OBJECTIVE

To investigate the associations between plasma levels of pentraxins 3 (PTX3) and C reactive protein (CRP) and the severity of coronary artery lesions.

DESIGN AND METHODS

60 patients with coronary heart disease (CHD) who underwent coronary angiography (CAG) in our hospital were included. Plasma was collected during CAG. The coronary Gensini score was used to evaluate the severity of coronary artery lesions. Associations between Gensini scores and plasma levels of PTX3 and CRP were analysed. Patients with estimated glomerular filtration rate <60 mL/min/1.73 m(2) were included in the chronic renal dysfunction subgroup.

RESULTS

A linear correlation was observed between PTX3 and the Gensini score (r=0.513, p<0.001). One-way analysis of variance showed that PTX3 levels were significantly higher in patients with Gensini scores >90 compared with patients with scores of 46-90 or <45 (0-45:4.8±0.8, 46-90:6.7±1.2, >90:7.7±2.0, p<0.001). Stepwise multiple linear regression showed that PTX3 levels were significantly associated with Gensini score in patients with chronic renal dysfunction (p=0.012), while no significant association was found for CRP.

CONCLUSIONS

PTX3 levers were positively associated with the severity of coronary artery lesions. PTX3 is closely associated with the severity of coronary artery stenosis in patients with chronic renal dysfunction.

The yin-yang of long pentraxin PTX3 in inflammation and immunity

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CRP and PTX3 are prototypical short and long pentraxin respectively.

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They are both soluble pattern recognition molecule involved in the innate immune and inflammatory response.

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PTX3 but not CRP is conserved in mouse and men and gene-modified mice help in the understanding of the biological properties.

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Protective and detrimental roles are exerted by PTX3.

Pentraxins are a family of multimeric proteins characterized by the presence of a pentraxin signature in their C-terminus region. Based on the primary structure, pentraxins are divided into short and long pentraxin: C-reactive protein (CRP) is the prototype of the short pentraxin subfamily while pentraxin 3 (PTX3) is the prototypic long pentraxin. Despite these two molecules exert similar fundamental actions in the regulation of innate immune and inflammatory responses, several differences exist between CRP and PTX3, including gene organization, protein oligomerization and expression pattern. The pathophysiological roles of PTX3 have been investigated using genetically modified mice since PTX3 gene organization and regulation are well conserved between mouse and human. Such in vivo studies figured out that PTX3 mainly have host-protective effects, even if it could also exert negative effects under certain pathophysiologic conditions. Here we will review the general properties of CRP and PTX3, emphasizing the differences between the two molecules and the regulatory functions exerted by PTX3 in innate immunity and inflammation.

Inflammatory biomarker pentraxin 3 (PTX3) in relation to obesity, body fat depots and weight loss

OBJECTIVE

The relation between inflammatory markers, adiposity and disease is under extensive study. Here we tested the hypothesis that the immunomodulatory protein pentraxin 3 (PTX3) is associated with adiposity in the general population.

METHODS

Serum PTX3 concentrations, body mass index (BMI), waist circumference (WC) and fat depots, as quantified by dual-energy X-ray absorptiometry and magnetic resonance imaging, were assessed in three community-based cohorts: ULSAM, n = 790, mean age 78 years; PIVUS, n = 1003, mean age 70 years, women 50%; and the NORDIET-trial, n = 86, mean age 53 years, women 63%. Participants were re-examined after 5 years (PIVUS, n = 804) or following a 6-week randomized controlled dietary intervention (NORDIET).

RESULTS

PTX3 levels were inversely associated with BMI and WC as well as with total and visceral fat (P < 0.05 for all; adjusted for age, inflammatory biomarkers and cardiovascular risk factors). The association between PTX3 and BMI appeared even stronger in nonobese individuals. A decrease in BMI over 5 years as well as weight loss following the NORDIET intervention were associated with increased serum PTX3 concentrations (P < 0.001).

CONCLUSIONS

These consistent data support an inverse association between circulating PTX3 and anthropometrical measures, calling for further mechanistic studies of the link between PTX3 and fat.

TREM-1 and pentraxin-3 plasma levels and their association with obstructive sleep apnea, obesity, and endothelial function in children

BACKGROUND

Obstructive sleep apnea (OSA) is a common health problem in children and increases the risk of cardiovascular disease (CVD). Triggering receptor expressed on myeloid cells-1 (TREM-1) plays an important role in innate immunity and amplifies inflammatory responses. Pentraxin-3 is predominantly released from macrophages and vascular endothelial cells, plays an important role in atherogenesis, and has emerged as a biomarker of CVD risk. Thus, we hypothesized that plasma TREM-1 and pentraxin-3 levels would be elevated in children with OSA.

METHODS

ONE HUNDRED SIX CHILDREN (MEAN AGE: 8.3 ± 1.6 y) were included after they underwent overnight polysomnographic evaluation and a fasting blood sample was drawn the morning after the sleep study. Endothelial function was assessed with a modified hyperemic test after cuff-induced occlusion of the brachial artery. Plasma TREM-1 and pentraxin-3 levels were assayed using commercial enzyme-linked immunosorbent assay kits. Circulating microparticles (MPs) were assessed using flow cytometry after staining with cell-specific antibodies.

RESULTS

Children with OSA had significantly higher TREM-1 and pentraxin-3 levels (versus controls: P < 0.01, P < 0.05, respectively). Plasma TREM-1 was significantly correlated with both body mass index (BMI)-z score and the obstructive apnea-hypopnea index (AHI) in univariate models. Pentraxin-3 levels were inversely correlated with BMI-z score (r = -0.245, P < 0.01), and positively associated with endothelial MPs and platelet MPs (r = 0.230, P < 0.01 and r = 0.302, P < 0.01). Both plasma TREM-1 and pentraxin-3 levels were independently associated with AHI in multivariate models after controlling for age, sex, race, and BMI-z score (P < 0.001 for TREM-1 and P < 0.001 for pentraxin-3). However, no significant associations emerged between TREM-1, pentraxin-3, and endothelial function.

CONCLUSIONS

Plasma TREM-1 and pentraxin-3 levels are elevated in pediatric OSA, and may play a role in modulating the degree of systemic inflammation. The short-term and long-term significance of elevated TREM-1 and pentraxin-3 in OSA-induced end-organ morbidity remains to be defined.

Elevated circulating levels and tissue expression of pentraxin 3 in uremia: a reflection of endothelial dysfunction

Elevated systemic pentraxin 3 (PTX3) levels appear to be a powerful marker of inflammatory status and a superior outcome predictor in patients with chronic kidney disease (CKD). As previous data imply that PTX3 is involved in vascular pathology and that adipose tissue mass may influence circulating PTX3 levels, we aimed to study the importance of adipose tissue expression of PTX3 in the uremic milieu and its relation to endothelial dysfunction parameters. Plasma PTX3 and abdominal subcutaneous adipose tissue (SAT) PTX3 mRNA levels were quantified in 56 stage 5 CKD patients (median age 57 [range 25-75] years, 30 males) and 40 age and gender matched controls (median age 58 [range 20-79] years, 27 males). Associations between PTX3 measures and an extensive panel of clinical parameters, including surrogate markers of endothelial function, were assessed. Functional ex vivo studies on endothelial status and immunohistochemical staining for PTX3 were conducted in resistance subcutaneous arteries isolated from SAT. SAT PTX3 mRNA expression correlated with plasma PTX3 concentrations (rho = 0.54, p = 0.0001) and was increased (3.7 [0.4-70.3] vs. 1.2 [0.2-49.3] RQ, p = 0.02) in CKD patients with cardiovascular disease (CVD), but was not significantly different between patients and controls. The association to CVD was lost after adjustments. SAT PTX3 mRNA levels were independently correlated to asymmetric dimethylarginine and basal resistance artery tone developed after inhibition with nitric oxide synthase and cyclooxygenase (rho = -0.58, p = 0.002). Apparent positive PTX3 immunoreactivity was observed in both patient and control arteries. In conclusion, fat PTX3 mRNA levels are associated with measures of endothelial cell function in patients with CKD. PTX3 may be involved in adipose tissue-orchestrated mechanisms that are restricted to the uremic milieu and modify inflammation and vascular complications in CKD patients.

The long pentraxin PTX3: a candidate anti-inflammatory mediator in cardiac surgery

Coronary artery bypass grafting (CABG) is performed with the use of cardiopulmonary bypass (CPB) and cardioplegic arrest (CA) of the heart. The advantage of this technique, alternatively referred to as “on-pump” surgery, resides, for the surgeon, in relatively easy access to and manipulation with the non-beating, bloodless heart. However, the advantage that is, thereby, gained by the patient is paid off by an increased susceptibility to postoperative systemic inflammatory response syndrome (SIRS). Under unfavorable conditions, the inflammatory syndrome may develop into life-threatening forms of MODS (multiple organ dysfunction syndrome) or even MOFS (multiple organ failure syndrome). Deliberate avoidance of CPB, also known as “off-pump” surgery, attenuates early postoperative inflammation throughout its trajectory of SIRS→MODS→MOFS, but, in the long run, there appears to be no substantial difference in the overall mortality rates. In the last years, our knowledge of the pathophysiology of surgical inflammation has increased considerably. Recent findings, highlighting the as yet rather obscure role of pentraxin 3 (PTX3) in these processes, are discussed in this review article.

Pentraxins in nephrology: C-reactive protein, serum amyloid P and pentraxin-3

Every clinician uses C-reactive protein (CRP) levels as a biomarker for systemic inflammation in acute disorders. Nephrologists also consider CRP levels as a predictor for overall mortality in patients with chronic kidney disease or end-stage renal disease. But what is the biological function of CRP? CRP is a member of the family of pentraxins, which are small pentameric innate immunity effector proteins. Pentraxins are absent or weakly expressed during homeostasis. However, the pro-inflammatory cytokines interleukin (IL)-1, IL-6 and tumour necrosis factor induce CRP and serum amyloid P (SAP) in hepatocytes, whereas the long pentraxins, such as pentraxin (PTX)-3, are produced in peripheral tissues and monocytic phagocytes. Pentraxins opsonize pathogens or other particles such as dead cells, for their phagocytic clearance or induce pathogen killing in extracellular compartments. In this review, we discuss the immunoregulatory properties of the different members of the pentraxin family. We discuss the evolving evidence demonstrating their roles in acute and chronic forms of kidney disease and the significance of SAP and PTX3 as additional biomarkers of innate immune activation and systemic inflammation.

Pentraxins and Alzheimer's disease: at the interface between biomarkers and pharmacological targets

Alzheimer's disease (AD) is a neurodegenerative disorder involving deposition of misfolded proteins in vulnerable brain regions leading to inexorable and progressive neuronal loss and deterioration of cognitive functions. The AD brain displays features typical of chronic inflammation as defined by the presence of activated microglia and by an excessive amount of neuroinflammatory components such as cytokines and acute-phase proteins. This review aims to shed light on the role of the immune processes involved in AD, focusing on a family of inflammatory modulators belonging to the acute-phase proteins and crucial components of the humoral arm of innate immunity: pentraxins. In particular we analyze function of the pentraxins in AD, their upregulation in the brain and their contribution to neurodegeneration. Additionally, we highlight the role of pentraxins as putative AD biomarkers and as pharmacological therapeutic targets.

Long pentraxin 3 (PTX3) in the light of its structure, mechanism of action and clinical implications

Pentraxins are a group of evolutionarily conserved ancient proteins. Depending on their structure, pentraxins are divided into short and long pentraxin families. Pentraxin 3 (PTX3) is the prototype of the long pentraxin group. PTX3 synthesis is stimulated by a variety of molecules involved in the inflammatory process. The inflammatory mediator is typically produced at inflammatory sites; however, it can also be released at the sites remote from the original inflammatory insult. Although mainly expressed by vascular endothelium and smooth muscle cells, PTX3 is also synthesized by myeloid dendritic cells, mononuclear macrophages/phagocytes, vascular endothelial and smooth muscle cells, fibroblasts, adipocytes, cumulus oophorus cells mesangial cells, synovial cells and chondrocytes. PTX3 binds to several ligands including complement component C1q, factor H, ficolin-1 (M-ficolin), mannose-binding lectin, fibroblast growth factor 2, P-selectin, matrix protein TSG6 and Klebsiella pneumoniae; it is also known to play a role in humoral innate immunity as well as in degenerated and apoptotic cells clearance. PTX3 acts as a modulator of inflammatory processes, modifies angiogenesis and atherosclerotic lesion development, and participates in extracellular matrix formation. Due to the fact of PTX3 being primarily produced and released by vascular wall cells, it might be used as a sensitive and independent inflammatory marker.

Hospital mortality of patients with severe traumatic brain injury is associated with serum PTX3 levels

BACKGROUND

Traumatic brain injury (TBI) is a worldwide cause of morbidity and mortality. Pentraxin 3 (PTX3) is a humoral component of the innate immune system which has been studied as a marker of inflammatory, infections or cardiovascular pathologies. To investigate the association between serum levels of PTX3 and the hospital mortality of patients with severe TBI.

METHODS

The independent association between serum PTX3 levels after severe TBI (Glasgow Coma Scale, GCS ≤ 8) and hospital mortality was analyzed in a prospective study of 83 consecutive patients by a multiple logistic regression analysis. The leukocyte count in the same sample was analyzed as another marker of inflammatory response.

RESULTS

The mean age of patients was 35 years and 85% were male. Serum PTX3 levels were determined 18.0 (SD ± 17.0) h after TBI. Patients who died showed a mean serum PTX3 level of 9.95 μg/ml (SD ± 6.42) in comparison to 5.46 μg/ml (SD ± 4.87) of the survivor group (P = 0.007). Elevated serum PTX3 levels remain significantly associated with mortality (P = 0.04) in the subset of patients with isolated TBI (n = 34). There were no differences in the leukocytes count measured in the same blood sample used for PTX3 determination in survivors and non-survivors (P = 0.56). The final multiple logistic regression model including age, pupillary examination, GCS, associated trauma, and PTX3 levels shows that serum levels of PTX3 which were higher than 10 μg/ml were independently associated with the patients mortality (adjusted OR 3.06, CI 95% 1.03-9.15, P = 0.04).

CONCLUSIONS

Serum PTX3 levels after severe TBI are independently associated with higher hospital mortality and may be a useful marker of TBI and its prognosis.

Pentraxins in innate immunity: lessons from PTX3

The innate immune system constitutes the first line of defence against microorganisms and plays a primordial role in the activation and regulation of adaptive immunity. The innate immune system is composed of a cellular arm and a humoral arm. Components of the humoral arm include members of the complement cascade and soluble pattern recognition molecules (PRMs). These fluid-phase PRMs represent the functional ancestors of antibodies and play a crucial role in the discrimination between self, non-self and modified-self. Moreover, evidence has been presented that these soluble PRMs participate in the regulation of inflammatory responses and interact with the cellular arm of the innate immune system. Pentraxins consist of a set of multimeric soluble proteins and represent the prototypic components of humoral innate immunity. Based on the primary structure of the protomer, pentraxins are divided into two groups: short pentraxins and long pentraxins. The short pentraxins C-reactive protein and serum amyloid P-component are produced by the liver and represent the main acute phase proteins in human and mouse, respectively. The long pentraxin PTX3 is produced by innate immunity cells (e.g. PMN, macrophages, dendritic cells), interacts with several ligands and plays an essential role in innate immunity, tuning inflammation and matrix deposition. PTX3 provides a paradigm for the mode of action of humoral innate immunity.