Antithrombin III inhibits lymphocyte proliferation, immunoglobulin production and mRNA expression of lymphocyte growth factors (IL-2, gamma-IFN and IL-4) in vitro

Relationship between Antithrombin III Activity and Mortality in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

We aimed to explore the role of antithrombin III (AT-III) activity in diagnosing patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and chronic bronchitis, and its relationship with all-cause mortality of AECOPD patients. We performed univariate and multivariate Cox regression analyses of the factors determining all-cause mortality. We recruited 279 patients with AECOPD and 91 with chronic bronchitis. On admission, patients with AECOPD had lower AT-III activity (80.7 vs. 86.35%, p = 0.002) and higher neutrophil percentages (70.12 vs. 66.40%, p = 0.02) than those with chronic bronchitis. The patients who died were older (78 vs. 73 years, p < 0.001); had higher CRP (39.05 vs. 5.65 mg/L, p < 0.001), D-dimer (1.72 vs. 0.46 mg/L, p < 0.001), FIB (3.56 vs. 3.05 g/L, p = 0.01) levels; and exhibited lower AT-III activity (71.29 vs. 82.94%, p < 0.001) than the survivors. The AT-III area under the receiver operating characteristic curve for predicting COPD all-cause mortality was 0.75 (p < 0.001), optimal cutoff point 79.75%, sensitivity 86.8%, and specificity 57.1%. Multivariate Cox regression analyses showed that increased levels of CRP (HR = 1.005, p = 0.02), D-dimer (HR = 1.17, p = 0.01), WBC count (HR = 1.11, p = 0.002), and reduced AT-III activity (HR = 0.97, p = 0.02) were independent prognostic factors for all-cause mortality. Patients with AT-III ≤ 79.75% were 4.52 times (p = 0.001) more likely to die than those with AT-III > 79.75%. AT-III activity was lower in patients with AECOPD than in those with chronic bronchitis and is potentially useful as an independent predictor of all-cause mortality in patients with AECOPD: reduced AT-III activity and increased CRP and D-dimer levels indicate a higher risk of all-cause mortality.

Snai2 and Snai3 transcriptionally regulate cellular fitness and functionality of T cell lineages through distinct gene programs

T lymphocytes are essential contributors to the adaptive immune system and consist of multiple lineages that serve various effector and regulatory roles. As such, precise control of gene expression is essential to the proper development and function of these cells. Previously, we identified Snai2 and Snai3 as being essential regulators of immune tolerance partly due to the impaired function of CD4(+) regulatory T cells in Snai2/3 conditional double knockout mice. Here we extend those previous findings using a bone marrow transplantation model to provide an environmentally unbiased view of the molecular changes imparted onto various T lymphocyte populations once Snai2 and Snai3 are deleted. The data presented here demonstrate that Snai2 and Snai3 transcriptionally regulate the cellular fitness and functionality of not only CD4(+) regulatory T cells but effector CD8(α+) and CD4(+) conventional T cells as well. This is achieved through the modulation of gene sets unique to each cell type and includes transcriptional targets relevant to the survival and function of each T cell lineage. As such, Snai2 and Snai3 are essential regulators of T cell immunobiology.

The role of the vessel wall

The role of the vessel wall is complex and its effects are wide-ranging. The vessel wall, specifically the endothelial monolayer that lines the inner lumen, possesses the ability to influence various physiological states both locally and systemically by controlling vascular tone, basement membrane component synthesis, angiogenesis, haemostatic properties, and immunogenicity. This is an overview of the function and structure of the vessel wall and how disruption and dysfunction in any of these regulatory roles can lead to disease states.

Coagulation and inflammation. Molecular insights and diagnostic implications

Overwhelming evidence has linked inflammatory disorders to a hypercoagulable state. In fact, thromboembolic complications are among the leading causes of disability and death in many acute and chronic inflammatory diseases. Despite this clinical knowledge, coagulation and immunity were long regarded as separate entities. Recent studies have unveiled molecular underpinnings of the intimate interconnection between both systems. The studies have clearly shown that distinct pro-inflammatory stimuli also activate the clotting cascade and that coagulation in turn modulates inflammatory signaling pathways. In this review, we use evidence from sepsis and inflammatory bowel diseases as a paradigm for acute and chronic inflammatory states in general and rise hypotheses how a systematic molecular understanding of the "inflammation-coagulation" crosstalk may result in novel diagnostic and therapeutic strategies that target the inflammation-induced hypercoagulable state.

The interface between coagulation and immunity

Coagulation proteases are involved in generating fibrin after vascular injury (hemostasis) but they also have multiple other effects, many of which are mediated independently of fibrin generation, via interactions with specific cell membrane-expressed "protease activated receptors". In inflammation, this family of proteins has a complex influence, the facets of which are still incompletely understood, though a common feature in different models appears to be amplification of innate signals that are initially generated by pathogenic elements or, in the context of transplantation, ischemia or anti-graft antibodies, for instance. There is increasing evidence that these proteases may also have specific effects on cells involved in adaptive immunity and on cells that mediate chronic inflammation and fibrosis. Understanding whether these effects are relevant in the responses generated against transplanted organs is important, as it could lead ultimately to the development of novel ways to promote long-term graft survival.

Tissue factor upregulation drives a thrombosis-inflammation circuit in relation to cardiovascular complications

The extrinsic coagulation is recognized as an 'inducible' signalling cascade resulting from tissue factor (TF) upregulation by exposure to clotting zymogen FVII upon inflammation or tissue injury. Following the substantial initiation, an array of proteolytic activation generates mediating signals (active serine proteases: FVIIa, FXa and FIIa) that lead to hypercoagulation with fibrin overproduction manifesting thrombosis. In addition, TF upregulation plays a central role in driving a thrombosis-inflammation circuit. Coagulant mediators (FVIIa, FXa and FIIa) and endproduct (fibrin) are proinflammatory, eliciting tissue necrosis factor, interleukins, adhesion molecules and many other intracellular signals in different cell types. Such resulting inflammation could ensure 'fibrin' thrombosis via feedback upregulation of TF. Alternatively, the resulting inflammation triggers platelet/leukocyte/polymononuclear cell activation thus contributing to 'cellular' thrombosis. TF is very vulnerable to upregulation resulting in hypercoagulability and subsequent thrombosis and inflammation, either of which presents cardiovascular risks. The prevention and intervention of TF hypercoagulability are of importance in cardioprotection. Blockade of inflammation reception and its intracellular signalling prevents TF expression from upregulation. Natural (activated protein C, tissue factor pathway inhibitor, or antithrombin III) or pharmacological anticoagulants readily offset the extrinsic hypercoagulation mainly through FVIIa, FXa or FIIa inhibition. Therefore, anticoagulants turn off the thrombosis-inflammation circuit, offering not only antithrombotic but anti-inflammatory significance in the prevention of cardiovascular complications.

Expression, by functional proteomics, of spontaneous tolerance in rat orthotopic liver transplantation

Orthotopic liver transplants (OLT) performed in certain combinations of donor and recipient rat strains, such as DA (RT1a) to PVG (RT1c), without immunosuppressive drugs could completely overcome major histocompatibility complex barriers. Although other organs transplanted in a similar fashion within the same combination have been promptly rejected, 60 day post-OLT serum (POD 60) has been proven competent in rapidly reversing the established rejection in animal models. In order to understand the functional role of tolerogenic serum proteins and their involvement with immune response regulation, a comprehensive analysis surveying global changes in complex OLT systems by proteomic techniques was applied. The results display the varying protein expressions in sera extracted from naïve and transplanted animals on POD 60 with regard to immunosuppression. Among these proteins, haptoglobin (Hp) which is related to inhibition of T-cell proliferation was found to be up-regulated following OLT. In addition, the transcriptional expression level and intracellular localization of Hp correlated with the immune events. Hp also exhibited a strong in vitro immunosuppressive effect on the mixed lymphocyte reaction. In conclusion, the presence of Hp may play an important role in modulating the spontaneous tolerance of liver transplantation. Furthermore, the serum proteome map could provide guidance with respect to discovering potential protein targets in OLT tolerance and eventually prolong hepatic allograft survival in the future.

High dose of antithrombin III induces indefinite survival of fully allogeneic cardiac grafts and generates regulatory cells

BACKGROUND

The authors investigated whether antithrombin III (AT-III) could induce unresponsiveness to alloantigens.

METHODS

CBA mice were given intravenous injection of 50 or 500 U/kg AT-III or control plasma the same day as transplantation of a heart from a C57BL/6 mouse. An adoptive transfer study and mixed leukocyte culture analysis were also performed.

RESULTS

Naive CBA mice rejected C57BL/6 cardiac grafts acutely (median survival time [MST], 9 days). The 50-U/kg dose of AT-III induced a moderate increase in graft survival (MST, 25 days), whereas control mice rejected their graft acutely (MST, 7 days). With the 500-U/kg dose of AT-III, all grafts survived indefinitely (>100 days) and regulatory cells were generated. In vitro, AT-III suppressed proliferation of mixed leukocyte responses and generation of interleukin-2.

CONCLUSION

AT-III can be not only an antithrombotic agent but also a strong immunomodulating agent when used at high dose.