Changes in cellular proliferation and plasma products are associated with liver failure

In vivo evidence for extracellular DNA trap formation

Extracellular DNA trap formation is a cellular function of neutrophils, eosinophils, and basophils that facilitates the immobilization and killing of invading microorganisms in the extracellular milieu. To form extracellular traps, granulocytes release a scaffold consisting of mitochondrial DNA in association with granule proteins. As we understand more about the molecular mechanism for the formation of extracellular DNA traps, the in vivo function of this phenomenon under pathological conditions remains an enigma. In this article, we critically review the literature to summarize the evidence for extracellular DNA trap formation under in vivo conditions. Extracellular DNA traps have not only been detected in infectious diseases but also in chronic inflammatory diseases, as well as in cancer. While on the one hand, extracellular DNA traps clearly exhibit an important function in host defense, it appears that they can also contribute to the maintenance of inflammation and metastasis, suggesting that they may represent an interesting drug target for such pathological conditions.

Extracellular Mitochondrial DNA and N-Formyl Peptides in Trauma and Critical Illness: A Systematic Review

OBJECTIVES

Extracellular mitochondrial DNA and N-formyl peptides released following tissue damage may contribute to systemic inflammation through stimulation of the innate immune system. In this review, we evaluate existing in vivo human data regarding a role for mitochondrial DNA and N-formyl peptides in producing systemic inflammation in trauma and critical illness, investigate the utility of these molecules in risk prediction and clinical decision support, and provide suggestions for standardization of future research.

DATA SOURCES

PubMed, Embase (1971-2017).

STUDY SELECTION

Studies measuring extracellular mitochondrial DNA and/or N-formyl peptides in acutely ill patients.

DATA EXTRACTION

Fifty-four studies were analyzed. Data extracted included article characteristics, methods, results, and performance in clinical prediction.

DATA SYNTHESIS

The most common patient types investigated were trauma (19 studies) and sepsis (eight). In studies comparing patient mitochondrial DNA or N-formyl peptide levels to healthy controls, 38 (90.5%) reported significantly elevated mitochondrial DNA levels in patients at first reported time point, as did the one study making this comparison for N-formyl peptides. Nine studies (81.8%) reported significantly elevated plasma/serum mitochondrial DNA levels in at least one time point in patients who developed inflammatory complications of their primary pathology compared with patients without inflammatory complications. For the ability of mitochondrial DNA to predict complications or outcomes, the area under the curve was 0.7 or greater in 84.6% of receiver operating characteristic curves, and 92.9% of odds, adjusted odds, risk, and hazard ratios were statistically significant.

CONCLUSIONS

Extracellular mitochondrial DNA levels are elevated early in patients' hospital courses in many acute illnesses and are higher in patients who develop inflammatory complications. Elevated mitochondrial DNA levels may be clinically useful in risk prediction and clinical decision support systems. Further research is needed to determine the role of extracellular N-formyl peptides in systemic inflammation and their possible clinical utility.

Complement System as a Target for Therapies to Control Liver Regeneration/Damage in Acute Liver Failure Induced by Viral Hepatitis

The complement system plays an important role in innate immunity inducing liver diseases as well as signaling immune cell activation in local inflammation regulating immunomodulatory effects such as liver damage and/or liver regeneration. Our aim is to evaluate the role of complement components in acute liver failure (ALF) caused by viral hepatitis, involving virus-induced ALF in human subjects using peripheral blood, samples of liver tissues, and ex vivo assays. Our findings displayed low levels of C3a in plasma samples with high frequency of C3a, C5a, and C5b/9 deposition in liver parenchyma. Meanwhile, laboratory assays using HepG2 (hepatocyte cell line) showed susceptibility to plasma samples from ALF patients impairing in vitro cell proliferation and an increase in apoptotic events submitting plasma samples to heat inactivation. In summary, our data suggest that the complement system may be involved in liver dysfunction in viral-induced acute liver failure cases using ex vivo assays. In extension to our findings, we provide insights into future studies using animal models for viral-induced ALF, as well as other associated soluble components, which need further investigation.

Decreased activity of plasma ADAMTS13 are related to enhanced cytokinemia and endotoxemia in patients with acute liver failure

Deficient ADAM metalloproteinase with thrombospondin type-1 motif, member 13 (ADAMTS13) activity (ADAMTS13:AC) results in the accumulation of unusually large von Willebrand factor multimers (UL-VWFM) and causes microcirculatory disturbances and multiple organ failure, while endotoxins trigger the activation of a coagulation cascade. The objective of the present study was to explore the role of ADAMTS13 in endotoxemia in patients with acute liver failure (ALF). Plasma concentrations of endotoxin and cytokines, including interleukin (IL)-6 and IL-8, and activity of the plasma ADAMTS13 inhibitor were determined, along with ADAMTS13:AC, the VWF antigen (VWF:Ag) and UL-VWFM, in 27 patients with acute hepatitis (AH), 11 patients with ALF, and 10 healthy controls. IL-6 and IL-8 concentrations on admission were significantly higher in patients with ALF than in those with AH or in healthy controls. ADAMTS13:AC concomitantly decreased and VWF:Ag progressively increased with increasing cytokine concentrations from the normal range to >100 pg/ml. The inhibitor was detected in 8 patients with ALF (0.6 to 2.4 BU/ml) and 6 patients with AH (0.6 to 0.8 BU/ml). Patients with the inhibitor reported lower ADAMTS13:AC, higher VWF:Ag and lower functional liver capacity than those without the inhibitor. Collectively, the findings suggested that decreased ADAMTS13:AC and increased VWF:Ag may be induced by pro-inflammatory cytokinemia as well as the presence of the ADAMTS13 inhibitor, both of which may be closely related to enhanced endotoxemia in patients with ALF.