Patients with acute pancreatitis complicated by organ dysfunction show abnormal peripheral blood polymorphonuclear leukocyte signaling

BACKGROUND/OBJECTIVES

Circulating polymorphonuclear leukocytes (PMNLs) may contribute to development of organ dysfunction in acute pancreatitis (AP). We outlined aberrations in PMNL signaling profiles in patients with AP complicated by organ dysfunction and immune suppression.

METHODS

Study comprised 13 patients treated at intensive care unit due to severe AP complicated by vital organ dysfunction. Mean proportion (SEM) of HLA-DR-positive monocytes was 55.0% (4.1%). 13 healthy volunteers served as reference subjects. Phosphorylation of PMNL NFκB, p38, ERK1/2 and STAT3, -5 and -6 was determined using whole blood flow cytometry. Transmigration of PMNLs was studied using endothelial EA-HY cell monolayer.

RESULTS

Proportions of NFκB phosphorylation-positive PMNLs were lower in the patients' than in reference subjects' blood samples supplemented with tumor necrosis factor. p38 phosphorylation was normal while ERK1/2 phosphorylation was decreased. STAT3 was constitutively activated in five patients. Proportion of patients' pSTAT6-positive cells was normal while fluorescence intensity was decreased. STAT5 phosphorylation was normal. Transmigration of patients' PMNLs was increased.

CONCLUSIONS

In patients with AP complicated by organ dysfunction proportion of pNFκB-positive PMNLs is decreased. This impairs patients' defense mechanisms against infection. Despite immune suppression, PMNL transmigration was increased and p38 phosphorylation capacity was not depressed, which may contribute to end organ inflammation and dysfunction.

Specific Immunoassay Reveals Increased Serum Trypsinogen 3 in Acute Pancreatitis

BACKGROUND

Trypsinogen 3 is a minor trypsinogen isoform in the pancreas. In contrast with trypsin 1 and 2, trypsin 3 degrades pancreatic secretory trypsin inhibitor, which may lead to an excess of active trypsin and acute pancreatitis (AP). We developed an immunoassay for trypsinogen 3 and studied whether an assay of serum trypsinogen 3 is of clinical utility in the diagnosis of AP.

METHODS

Monoclonal antibodies were generated using recombinant human trypsinogen 3 as the antigen and used to establish a sandwich-type immunoassay. We analyzed serum trypsinogen 3 concentrations in 82 patients with AP and 63 patients with upper abdominal pain (controls). The reference interval was determined using serum samples from 172 apparently healthy individuals.

RESULTS

The measuring range of the trypsinogen 3 assay was 1.0–250 μg/L. Intra- and interassay CVs were <11%, and cross-reactivity with other trypsinogen isoenzymes was <0.1%. The median trypsinogen 3 concentration in serum from healthy individuals was <1.0 μg/L, and the upper reference limit was 4.4 μg/L. We observed increased trypsinogen 3 concentrations in patients with mild (median 9.5 μg/L) and severe (15.0 μg/L) AP; in both groups, the concentrations were significantly higher than in controls (median <1.0 μg/L) (P < 0.0001). In ROC analysis, the area under the curve of trypsinogen 3 for separation between AP and controls was 0.90 (P < 0.0001).

CONCLUSIONS

We established for the first time a specific immunoassay for trypsinogen 3 using monoclonal antibodies. Patients with AP were found to have increased serum concentrations of trypsinogen 3. The availability of this assay will be useful for studies of the clinical utility of trypsinogen 3.

Acute pancreatitis with organ dysfunction associates with abnormal blood lymphocyte signaling: controlled laboratory study

Introduction

Severe acute pancreatitis is associated with systemic inflammation, compensatory immune suppression, secondary infections, vital organ dysfunction, and death.

Our study purpose was to delineate signaling profiles of circulating lymphocytes in acute pancreatitis complicated by organ dysfunction.

Methods

Sixteen patients with acute pancreatitis, dysfunction of vital organ(s), and immune suppression (proportion of HLA-DR Human Leukocyte Antigen - DR - positive monocytes < 80%) participated. Healthy volunteers served as reference subjects. Using phospho-specific whole blood flow cytometry we studied lymphocyte phosphorylation of nuclear factor-κB (NFκB), mitogen-activated protein kinases p38 and extracellular signal-regulated kinases (ERK)1/2, and signal transducers and activators of transcription (STATs) 1, 3, and 6. Statistical comparisons were performed with the Wilcoxon-Mann-Whitney test.

Results

In blood samples supplemented with tumor necrosis factor, E. coli or S. aureus, phosphorylation levels of NFκB were lower and levels of p38 were higher in patients with acute pancreatitis than healthy subjects. Low NFκB activation involved CD3+CD4+ and CD3+CD8+ lymphocytes. ERK1/2 phosphorylation induced by co-stimulation with phorbol 12-myristate 13-acetate and calcium ionophore A23187 was depressed in patients. STAT3 was constitutively activated in patients' CD3+CD4+ and CD3+CD8+ lymphocytes. Also, IL-6-induced STAT1 phosphorylation was impaired while IL-4-induced STAT6 phosphorylation was enhanced.

Conclusions

Lymphocytes of patients with acute pancreatitis, organ dysfunction and immune suppression show impaired NFκB activation, which increases infection risk and enhanced p38 activation, which sustains inflammation. Secondly, they indicate constitutive STAT3 activation, which may favor Th17 lineage of CD4+ lymphocyte differentiation. Thirdly, they reveal impaired STAT1 activation and enhanced STAT6 activation, denoting a shift from Th1 towards Th2 differentiation.

Calcification and cellularity in human aortic heart valve tissue determine the differentiation of bone-marrow-derived cells

Human bone-marrow-derived mesenchymal stem cells (MSC) are responsible the remodeling of human tissue. However, damaged aortic valves are lack the ability to regenerate which is an active cell-mediated process. Diseased aortic valve remodeling has similarities even to bone formation. In this study, the prerequisites for cultured MSCs to undergo osteoblastic differentiation on aortic valves were explored. An ex vivo model using a human aortic valve microenvironment was developed. The expression of type I procollagen, alkaline phosphatase activity, osteocalcin secretion and osteocalcin immunostaining were studied to evaluate the induction of osteogenesis of the MSCs on noncalcified and calcified human aortic valves. Aortic valves were exposed to freeze-thaw injury to devitalize valves in order to separately study the role of valve matrix vs. endothelial cells in the explants. Thus, valves were assigned to 1 of 4 treatment groups: noncalcified uninjured valves, calcified uninjured valves, noncalcified injured and calcified injured. Finally, valves were decalcified to separately explore the effect of a calcified matrix on the osteogenesis. In this co-culture system, the noncalcified uninjured valves inhibited osteogenesis of MSCs, whereas the calcified valves promoted differentiation towards osteoblastic lineage. Devitalization of the valve matrix inflicted a significant increase in the osteogenesis of co-cultured MSCs. Calcified matrix in the valves seemed to have a role in the spontaneous osteogenesis of the MSCs. This spontaneous matrix induced differentiation of MSCs into osteoblast lineage could not be inhibited by pravastatin, indomethacin or tetracycline. In conclusion, these results suggest that interactions between MSCs and aortic valve matrix components and cells modulate MSC phenotype in this environment. Further studies are required to characterize this interesting phenomenon in greater detail.

Chemically modified tetracyclines (CMT-3 and CMT-8) enable control of the pathologic remodellation of human aortic valve stenosis via MMP-9 and VEGF inhibition

OBJECTIVE

Tetracycline derivatives affect many cellular functions relevant to chronic cardiovascular pathologies, including cell proliferation, migration and matrix remodelling. Accordingly, we sought to determine whether they may modulate the pathologic characteristics known to be significantly involved in human aortic valve stenosis, such as gelatinase production, apoptosis, expression of vascular endothelial growth factor (VEGF) and tumour necrosis factor-alpha (TNF-alpha).

METHODS

The effects of tetracycline derivatives (tetracycline and CMTs-3, -5, -8) on MMP-2 and -9 and their endogenous tissue inhibitor (TIMP-1 and -2) production profiles in explanted human aortic valve pieces were examined by means of gelatine zymography and reverse zymography. Chemiluminescent ELISA was performed to assess VEGF and TNF-alpha concentrations in the medium, and in order to evaluate programmed cell death, in situ labelling of the 3'-ends of the DNA fragments generated by apoptosis-associated endonucleases was performed.

RESULTS

CMT-3 and -8 lowered the MMP-9 and VEGF levels significantly in a drug-, dose-, and time-dependent manner. MMP-2 and TIMPs remained unchanged, emphasizing the specificity of CMTs to MMP-9 production on the one hand and restoring the beneficial equilibrium of MMP-9 and TIMPs on the other. Tetracycline was the only drug with a significant impact on net gelatinolytic activity, suggesting that the effect of tetracycline is more extensive concerning total MMP activity.

CONCLUSIONS

Tetracycline derivatives may have therapeutic effects on the pathologic remodellation of advanced human aortic stenosis through the inhibition of MMP-9 and VEGF production.

Evidence for an altered balance between matrix metalloproteinase-9 and its inhibitors in calcific aortic stenosis

BACKGROUND

Recently, aortic valve stenosis has been demonstrated to exhibit increased expression of certain matrix metalloproteinases (MMPs), and this has relevantly raised the question about possible interdependency between these and their tissue inhibitors. We sought to assess the expression of elastolytic MMPs and their inhibitors (TIMPs) in nonrheumatic aortic stenosis.

METHODS

The study comprised 30 stenotic and six noncalcified human aortic valves. To measure the expression levels and the amount and molecular forms of gelatinases (MMP-2, MMP-9) and TIMPs (1, 2), in situ hybridization, gelatin zymography, and reverse zymography were carried out. Antielastin staining by a monoclonal BA-4 antibody was performed to investigate the changes of one of the main substrates of these MMPs, and to substantiate the nature of the putative MMP- synthesizing cell. The cases were also immunostained with an antibody to alpha-smooth muscle actin. Inflammatory cell characterization was managed by monoclonal mouse antibodies (UCHL-1, L26, and PGM-1).

RESULTS

Compared with the controls, the calcific valves showed increased mRNA expression and activation of MMP-9, and this was associated with typical characteristics of valve disease. MMP-2 mRNA production was rare, but proMMP-2 protein was detected in all valves. In agreement with the interdependency between MMP-9 and its inhibitors, a suggestive imbalance came out in diseased valves.

CONCLUSIONS

The disproportion between MMP-9 and its tissue inhibitors may favor a persistent MMP activation state within the calcific valve and likely contribute to the valvular remodeling process in the setting of developing aortic stenosis.