Inflammation and immune response in acute aortic dissection

Neutrophil to lymphocyte ratio: a novel marker for predicting hospital mortality of patients with acute type A aortic dissection

Introduction:

The inflammatory process has been reported to be associated with aortic dissection (AD) from the development to the prognosis. The aim of the study was to investigate a relationship between the neutrophil to lymphocyte ratio (NLR) and in-hospital outcomes in patients with acute aortic dissection (AAD) who underwent surgical repair.

Methods:

One hundred and eighty-four patients who were admitted with the diagnosis of type A AAD who underwent surgical repair at two large tertiary hospitals. According to their NLR, 91 patients had high NLR (>6.0) and 93 patients had low NLR (⩽6.0).

Results:

The frequency of major bleeding, hospital-related infection, multi-organ dysfunction and mortality in hospital were higher in the high NLR group compared to the low NLR group. NLR, WBC count and operation duration were found to be independent predictors for in-hospital mortality.

Conclusions:

The novel inflammatory marker NLR may be used to predict worse outcomes and hospital mortality in patients with AAD treated by surgical repair.

Impact of Admission White Blood Cell Count on Short- and Long-term Mortality in Patients With Type A Acute Aortic Dissection: An Observational Study

Studies have shown inflammation is involved in the development of acute aortic dissection (AAD). The hypothesis that white blood cell count (WBCc) on admission may have an impact on the short- and long-term outcomes of type A AAD was tested in a large-scale, prospective observational cohort study.From 2008 to 2010, a total of 570 consecutive patients with type A AAD in Fuwai hospital were enrolled and were followed up. Baseline characteristics and WBCc on admission were collected. The primary outcomes were 30-day and long-term all-cause mortality.During a median of 1.89 years of follow-up, the 30-day and long-term all-cause mortality were 10.7% and 6.5%, respectively. Univariate Cox regression analysis identified admission WBCc as an independent predictor of 30-day mortality when considered as a continuous variable or as a categorical variable using the cutoff of 11.0 × 10 cells/L (all P < 0.05). After adjustment for age, sex, C-reactive protein, D-dimer, and surgical intervention, elevated admission WBCc (>11.0 × 10 cells/L) remained an independent predictor of 30-day mortality of AAD (hazard ratio = 3.31, 95% confidence interval 1.38-7.93, P = 0.007). No impact of admission WBCc was observed on the long-term all-cause mortality.In conclusion, elevated admission WBCc may be valuable as a predictor of 30-day mortality, and may be useful in the risk stratification of type A AAD during hospitalization.

Impact of d-Dimer Levels on Admission on Inhospital and Long-Term Outcome in Patients With Type A Acute Aortic Dissection

Limited studies with relatively small sample sizes have reported that elevated d-dimer levels on admission were associated with increased risk of short-term mortality in patients with type A acute aortic dissection (AAD). However, there were unavailable data regarding the impact of admission d-dimer levels on long-term outcomes. Our present study aimed to evaluate the association of admission d-dimer levels with both inhospital and long-term all-cause mortality in patients with type A AAD. A total of 212 consecutive patients with type A AAD were enrolled. d-Dimer levels were measured on admission, and patients were followed up prospectively. The primary end points were inhospital and long-term all-cause mortality. The median length of follow-up was 18.8 months (interquartile range 6.7 to 24.4 months). The inhospital and long-term all-cause mortality rates were 12.7% and 12.4%, respectively. Compared with the survivors, the nonsurvivors had significantly higher d-dimer levels (p <0.001). When divided into 4 groups according to admission d-dimer quartiles, patients in Q4 (>6.10 μg/ml) had the highest inhospital and long-term mortality among groups. After multivariate adjustment, the d-dimer level in Q4 (>6.10 μg/ml) was an independent risk factor for inhospital mortality (hazard ratio [HR] 6.12, 95% confidence interval 1.35 to 27.89, p = 0.019) in addition to surgical treatment; however, this was not an independent predictor for long-term mortality. In conclusion, our study with a relatively large sample size suggested that elevated admission d-dimer levels (>6.10 μg/ml) might be a predictor for increased risk of inhospital mortality, and urgent-emergent surgery might be needed in patients with elevated d-dimer levels on admission. However, d-dimer levels at admission failed to predict long-term mortality.

FGF-23 levels in patients with critical carotid artery stenosis

The aim of this study was to evaluate fibroblast growth factor (FGF)-23 serum levels and its tissue expression in patients with critical carotid artery stenosis (CAS). We selected 35 patients with critical CAS undergoing carotid thromboendoarterectomy. In each patient, FGF-23 serum levels were evaluated just prior to the surgery (t0) and 30 min (t1) thereafter. Moreover, macrophage cytokines were measured at baselines. Carotid artery specimens were used for immune histochemistry. On the basis of the histology, the patients were divided into 2 groups: A with complicated plaque and B with uncomplicated plaque. Twenty complicated plaques (57.14%, group A,) and 15 uncomplicated (42.86%, group B) were evaluated: calcifications were present in 16/20 (80%) complicated plaques and in 6/15 (40%) uncomplicated plaques. An inflammatory infiltrate was observed in 26/35 carotid samples: 18/26 (69.23%) complicated and 8/26 (30.76%) uncomplicated. FGF-23(+) cells were present in 17/20 complicated (85%) and in 8 uncomplicated (53%) plaques. The double-staining immunofluorescence confirmed that macrophage cells (CD68(+)) were also positive for FGF-23 staining. Serum levels of FGF-23 were significantly higher in group A versus group B at t0 (p < 0.05) and t1 (p 0.0047). Moreover, in group A patients a significant increase of FGF-23 serum levels was observed at t1 in comparison with t0 (p 0.0011). Our results suggest that FGF-23 acts in the late phases of atherosclerotic disease and may potentially represent a marker of complications in critical CAS.

C-reactive protein, not cardiac troponin T, improves risk prediction in hypertensives with type A aortic dissection

BACKGROUND

The aim of the study was to evaluate prognostic role of inflammatory biomarkers, cardiac troponin T (cTnT) and D-dimer in type A acute aortic dissection (AAD) and to examine whether they might help in risk stratification beyond values of International Registry of Acute Aortic Dissection (IRAD) score.

METHODS

Baseline biomarkers were determined in 54 consecutive predominantly hypertensive patients with type A AAD and evaluated for in-hospital mortality.

RESULTS

After multivariable adjustment, the independent predictors of outcome were age (OR = 1.09; 95% CI 1.02-1.18), treatment strategy (OR = 0.11; 95% CI 0.02-0.06) and C-reactive protein (CRP) either as binary (OR = 7.06; 95% CI 1.34-37.36) or continuous variable (OR = 1.10; 95% CI 1.01-1.21). cTnT did not independently influence mortality. Receiver- operating characteristic (ROC) curve analysis showed significant link between CRP and outcome (area under the ROC curve, AUC = 0.79; p < 0.01). Values of CRP > 9.8 mg/l had 83% sensitivity and 80% specificity for predicting in-hospital mortality. Addition of CRP to IRAD score improved prediction of short-term outcome, AUC increased from 0.74 to 0.89 (p = 0.004).

CONCLUSION

Admission CRP has independent prognostic value in type A AAD and the addition of CRP to IRAD score improved discriminative capacity of in-hospital mortality irrespective of symptom duration and treatment strategy.

Stanford-A acute aortic dissection, inflammation, and metalloproteinases: a review

Acute aortic dissection (AAD) is a life-threatening disease with an incidence of about 2.6-3.6 cases per 100,000/year. Depending on the site of rupture, AAD is classified as Stanford-A when the ascending aortic thoracic tract and/or the arch are involved, and Stanford-B when the descending thoracic aorta and/or aortic abdominal tract are targeted. It was recently shown that inflammatory pathways underlie aortic rupture in both type A and type B Stanford AAD. An immune infiltrate has been found within the middle and outer tunics of dissected aortic specimens. It has also been observed that the recall and activation of macrophages inside the middle tunic are key events in the early phases of AAD. Macrophages are able to release metalloproteinases (MMPs) and pro-inflammatory cytokines which, in turn, give rise to matrix degradation and neoangiogenesis. An imbalance between the production of MMPs and MMP tissue inhibitors is pivotal in the extracellular matrix degradation underlying aortic wall remodelling in dissections occurring both in inherited conditions and in atherosclerosis. Among MMPs, MMP-12 is considered a specific marker of aortic wall disease, whatever the genetic predisposition may be. The aim of this review is, therefore, to take a close look at the immune-inflammatory mechanisms underlying Stanford-A AAD.

Angiotensin II mobilizes spleen monocytes to promote the development of abdominal aortic aneurysm in Apoe-/- mice

OBJECTIVE

Abdominal aortic aneurysm (AAA) is widespread among elderly people and results in progressive expansion and rupture of the aorta with high mortality. Macrophages, which are the main population observed within the site of aneurysm, are thought to derive from circulating monocytes although no direct evidence has been provided to date. In this study, we were particularly interested in understanding the trafficking behavior of monocyte subsets in AAA and their role in disease pathogenesis.

APPROACH AND RESULTS

Using bone marrow transplantation in Apoe(-/-) mice, we showed that circulating monocytes give rise to abdominal aortic macrophages in hypercholesterolemic mice submitted to angiotensin II (AngII). Detailed monitoring of monocyte compartmentalization revealed that lymphocyte antigen 6C(high) and lymphocyte antigen 6C(low) monocytes transiently increase in blood early after AngII infusion and differentially infiltrate the abdominal aorta. The splenic reservoir accounted for the mobilization of the 2 monocyte subsets after 3 days of AngII infusion. Spleen removal or lymphocyte deficiency in Apoe(-/-) Rag2(-/-) mice similarly impaired early monocyte increase in blood in response to AngII and protected against AAA development, independently of blood pressure. Reconstitution of Apoe(-/-) Rag2(-/-) mice with total splenocytes but not with B-cell-depleted splenocytes restored monocyte mobilization in response to AngII and enhanced susceptibility to AAA.

CONCLUSIONS

Taken together, the data show that lymphocyte antigen 6C(high) and lymphocyte antigen 6C(low) monocytes are mobilized from the spleen in response to AngII. Intriguingly, the process is dependent on the presence of B cells and significantly contributes to the development of AAA and the occurrence of aortic rupture.

The Predictive Value of Admission Fragmented QRS Complex for In-Hospital Cardiovascular Mortality of Patients with Type 1 Acute Aortic Dissection

BACKGROUND

Fragmented QRS (fQRS) arises from impaired ventricular depolarization due to heterogeneous electrical activation of ischemic and/or infarcted ventricular myocardium. The short- and long-term prognostic values of fQRS have been reported for myocardial infarction, heart failure, fatal cardiac arrhythmias, and sudden cardiac death. The aim of this study was to investigate the predictive value of admission fQRS complex for in-hospital cardiovascular mortality of patients with type 1 acute aortic dissection (AAD).

METHODS

In this retrospective study, 203 consecutive patients with type 1 AAD who had been admitted to either of two large-volume tertiary hospitals between December 2008 and October 2013 were included. The patients were divided into two groups according to the presence or absence of the fQRS complex on admission.

RESULTS

In-hospital cardiovascular mortality (P < 0.001), major adverse cardiovascular events (P < 0.001), acute renal failure (P = 0.022), multiorgan dysfunction (P < 0.001), and acute decompensated heart failure (P < 0.001) were observed to be significantly more frequent in the fQRS-positive group than in the fQRS-negative group. fQRS (odds ratio [95% confidence interval]: 4.184 [1.927-9.082], P < 0.001), operation duration (4.184 [1.927-9.082], P = 0.001), and Killip class IV (3.900 [1.699-8.955], P = 0.001) were found to be significant independent predictors of in-hospital cardiovascular mortality after adjustment of other risk factors in the multivariate analysis.

CONCLUSIONS

fQRS is a simple, inexpensive, and readily available electrocardiographic entity that provides an additional risk stratification level beyond that provided by conventional risk parameters in predicting in-hospital cardiovascular mortality in type 1 AAD.

Decreased expression of P54(nrb) /NonO correlates with collagen deposition and fibrosis in human aortic dissection

AIMS

Aortic dissection (AD) is characterized by changes in the extracellular matrix, including fibrosis with collagen production. P54(nrb) /NonO is known to be involved in collagen formation. In this study, we examined whether AD is associated with abnormal P54(nrb) /NonO expression.

METHODS AND RESULTS

Aortic specimens and serum were obtained from 10 patients with AD and 10 controls. In-vitro cultures of vascular smooth muscle cells (VSMCs) and adventitial fibroblasts (AFs) were obtained from organ donors. P54(nrb) /NonO protein and mRNA levels were determined by Western blot, immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction (quantitative real-time RT-PCR). To evaluate collagen expression, we stained tissue sections with Masson's trichrome. Serum concentration of TNF-α was determined by enzyme-linked immunosorbent assay (ELISA). Aortic P54(nrb) /NonO protein and mRNA were decreased in AD patients, compared with controls. Decreased P54(nrb) /NonO mRNA correlated significantly with increased collagen deposition and fibrosis in AD aortas. In VSMCs and AFs from normal human aortas, P54(nrb) /NonO was expressed strongly and localized to the nucleus.

CONCLUSIONS

Patients with AD exhibited significantly decreased expression of P54(nrb) /NonO. The significant correlation between P54(nrb) /NonO and collagen may point to novel thinking about collagen metabolism research in AD aorta.

JAK2-centered interactome hotspot identified by an integrative network algorithm in acute Stanford type A aortic dissection

The precise mechanisms underlying dissections, especially those without connective tissue diseases or congenital vascular diseases, are incompletely understood. This study attempted to identify both the expression profile of the dissected ascending aorta and the interactome hotspots associated with the disease, using microarray technology and gene regulatory network analysis. There were 2,737 genes differentially expressed between patients with acute Stanford type A aortic dissection and controls. Eight interactome hotspots significantly associated with aortic dissection were identified by an integrative network algorithm. In particular, we identified a JAK2-centered expression module, which was validated in an independent gene expression microarray data set, and which was characterized by over-expressed cytokines and receptors in acute aortic dissection cases, indicating that JAK2 may play a key role in the inflammatory process, which potentially contributes to the occurrence of acute aortic dissection. Overall, the analytical strategy used in this study offered the possibility to identify functional relevant network modules and subsequently facilitated the biological interpretation in the complicated disease.

MMP-12 as a new marker of Stanford-A acute aortic dissection

BACKGROUND

The study evaluated macrophage cytokines and macrophage metalloprotease (MMP)-12 levels in patients with Stanford-A acute aortic dissection (AAD) and in patients with critical carotid artery stenosis (CAS) compared with patients matched for age, sex, and traditional cardiovascular risk factors (RF). The aim was to identify possible early serum markers of risk for atherosclerotic complications.

MATERIALS AND METHODS

We selected 65 patients: 23 AAD patients, 21 CAS patients, 21 RF, and 10 healthy subjects (HS). In each patient and control serum, levels of interleukin (IL)-6, IL-8, tumour necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, vascular endothelial growth factor (VEGF), and MMP-12 were assessed by ELISA.

RESULTS

A significant increase of MMP-12, IL-6, and IL-8 levels in AAD versus CAS was found. Moreover, MMP-12 was shown to be significantly higher in AAD versus RF, but not in CAS versus RF. A significant increase of IL-6, IL-8, MCP-1, TNF-α, and VEGF levels was observed both in AAD and CAS versus RF.

CONCLUSIONS

The results suggest that MMP-12 may be considered to be a specific marker of Stanford-A AAD. Furthermore, the study confirmed that in AAD and CAS macrophage cytokines play a key role in the progression of the atherosclerotic disease towards complications.

The multitasking role of macrophages in Stanford type A acute aortic dissection

OBJECTIVES

The aim of the study was to determine whether the release by macrophages of matrix metalloproteinase (MMP)-12 and vascular endothelial growth factor (VEGF) - leading to inflammation, matrix degradation and neoangiogenesis - represents an effective pathway that underlies aortic wall remodeling in Stanford type A acute aortic dissection (AAD).

METHODS

Twenty-one consecutive patients with no genetic predisposition, with Stanford type A AAD were selected. In each patient, the levels of serum VEGF, MMP-12, serum interleukin (IL)-6, IL-8 and monocyte chemoattractant protein (MCP)-1 were evaluated using enzyme-linked immunosorbent assay. Ascending aortic specimens were collected for immunohistochemical identification of any presence of inflammatory infiltrate, VEGF and CD31 expression.

RESULTS

A significant increase in serum VEGF (p = 0.044), MMP-12 (p = 0.007), IL-6 (p = 0.0001), IL-8 (p = 0.0001) and MCP-1 (p = 0.0001) levels was observed in the AAD group compared to the control group. Furthermore, all AAD samples were positive for VEGF in the tunica media and showed vessel growth and immune-inflammatory infiltrate. A large number of cases (62.79%) showed inflammation at the edge of the dissection and approximately half (51.42%) showed neovessels growing at the edge of the dissection.

CONCLUSIONS

The results suggest that VEGF-mediated angiogenesis and matrix degradation play a role in AAD. Finally, we believe that MMP-12 should be considered a marker of AAD.

Molecular mechanisms of thoracic aortic dissection

Thoracic aortic dissection (TAD) is a highly lethal vascular disease. In many patients with TAD, the aorta progressively dilates and ultimately ruptures. Dissection formation, progression, and rupture cannot be reliably prevented pharmacologically because the molecular mechanisms of aortic wall degeneration are poorly understood. The key histopathologic feature of TAD is medial degeneration, a process characterized by smooth muscle cell depletion and extracellular matrix degradation. These structural changes have a profound impact on the functional properties of the aortic wall and can result from excessive protease-mediated destruction of the extracellular matrix, altered signaling pathways, and altered gene expression. Review of the literature reveals differences in the processes that lead to ascending versus descending and sporadic versus hereditary TAD. These differences add to the complexity of this disease. Although tremendous progress has been made in diagnosing and treating TAD, a better understanding of the molecular, cellular, and genetic mechanisms that cause this disease is necessary to developing more effective preventative and therapeutic treatment strategies.

Biological features of thoracic aortic diseases. Where are we now, where are we heading to: established and emerging biomarkers and molecular pathways

Thoracic aortic aneurysms (TAAs) and aortic dissections (ADs) are among the main causes of mortality and morbidity in Western countries. For this reason, the diagnosis, prevention and prediction of TAAs and ADs have become a very active area of research; in fact, it is important to monitor and predict the evolution of these diseases over time. It is also critical, in cases of doubtful diagnosis, to receive some guidance from biochemical assays, particularly in the case of ADs. Although biological testing for disease prediction has already been discussed several times, the role of biomarkers in TAAs and ADs is still under discussion for routine patient screening, periodical follow-up or for prompt diagnosis in emergency conditions. In this review, we update the current knowledge and new trends regarding the role of biomarkers in thoracic aortic diseases, focusing on established and emerging biomarkers in the fields of genetics, inflammation, haemostasis and matrix remodelling as well as on substances released upon cell damage. Other than D-dimer, a sensitive but not a specific marker for the diagnosis of AD that has been widely tested by several authors and currently seems a viable option in ambiguous cases, the remaining markers have been most frequently assessed in limited or mixed patient populations. This currently precludes their widespread adoption as diagnostic or prognostic tools, even if many of these markers are conceptually promising. In years to come, we expect that future studies will further clarify the diagnostic and prognostic features of several established and emerging biomarkers that, to date, are still in the translational limbo separating biological discovery from a practical clinical role.

The Role of Inflammation in Type a Aortic Dissection: A Pilot Study

Type A aortic dissection (TAAD) is a severe cardiovascular disease with high mortality rates. Current evidence suggests inflammation as the main mechanism of its complex pathophysiology. Accordingly, in this study the eventual presence of inflammatory cells in aorta specimens and any contribution of these cells in both apoptosis and metalloproteinase levels were assessed. The potential relationship between plasma inflammatory molecules and TAAD was also detected. In addition, implication in TAAD susceptibility of ten common and functional single nucleotide polymorphisms (SNP)s of six candidate genes (CCR5, TLR4, ACE, eNOs, MMP-9 and −2) was determined. Thus, histo-pathological and immunoistochemical aorta examination, TUNEL testing, genotyping of ten SNPs were performed. Levels of plasma inflammatory molecules were also determined using ELISA technique. A significant inflammatory infiltrate was observed in the examined aortas. Consistent with these data, significantly higher plasma levels of systemic inflammatory mediators characterized the cases. In addition, a high risk genotype significantly associated with TAAD susceptibility was identified. Thus, inflammation producing MMPs, cytokines and death mediators seem to be the shared pathological mechanism for TAAD in the population examined.

Vascular effects of glycoprotein130 ligands--part II: biomarkers and therapeutic targets

Glycoprotein130 (gp130) ligands are defined by the use of the common receptor subunit gp130 and comprise interleukin (IL)-6, oncostatin M (OSM), IL-11, leukemia inhibitory factor (LIF), cardiotrophin-1 (CT-1), cardiotrophin-like cytokine (CLC), ciliary neurotrophic factor (CNTF), IL-27 and neuropoietin (NP). In part I of this review we addressed the pathophysiological functions of gp130 ligands with respect to the vascular wall. In part II of this review on the vascular effects of gp130 ligands we will discuss data about possible use of these molecules as biomarkers to predict development or progression of cardiovascular diseases. Furthermore, the possibility to modulate circulating levels of gp130 ligands or their tissue expression by specific antibodies, soluble gp130 protein, renin-angiotensin-aldosterone system (RASS) inhibitors, statins, agonists of peroxisome proliferator-activated receptors (PPAR), hormone replacement therapy, nonsteroidal anti-inflammatory drugs (NSAID) or lifestyle modulating strategies are presented. Recent knowledge about the application of recombinant cytokines from the gp130 cytokine family as therapeutic agents in obesity or atherosclerosis is also summarized. Thus the purpose of this review is to cover a possible usefulness of gp130 ligands as biomarkers and targets for therapy in cardiovascular pathologies.