Role of Lipopolysaccharide and Cecal Ligation and Puncture on Blood Coagulation and Inflammation in Sensitive and Resistant Mice Models

Abstract

The hemostatic system is severely disturbed during endotoxemia, leading to a hypercoagulable state. However, it remains uncertain to what extent hypercoagulability is the critical factor in determining the clinical course rather than just the consequence of a severe systemic inflammatory response. To answer this question, we evaluated the evolution of hemostatic and inflammatory markers, as well as histological features, in mice sensitive and resistant to two models of endotoxemia: lipopolysaccharide-injection and cecal ligation puncture. Genetic (knockout mice) and pharmacological (PJ34) blockade of the nuclear enzyme PARP-1 was used to achieve resistance to the endotoxemia. In both models, endotoxemia resulted in antithrombin deficiency, decreased platelets, and fibrin deposition in organs, which were similar in all groups of mice. By contrast, proinflammatory mediators, inflammatory cell infiltration (especially that mediated by mononuclear cells), and organ degeneration were more intense in sensitive animals. Further studies supported a negative role for the triggering of the coagulation cascade in the mortality associated with the endotoxic shock. Hirudin had a minor effect on cell infiltration and organ damage, despite causing a potent inhibition of fibrin deposition. On the other hand, a sublethal dose of lipopolysaccharide yielded significant fibrin deposition but weak activation of the inflammatory response. Our results suggest that activation of coagulation by endotoxemia is severe and independent of the inflammatory response. However, such activation may act with fibrin deposition to have a minor influence on survival in sepsis.

Inhibition of poly(ADP-ribose) polymerase attenuates the severity of acute pancreatitis and associated lung injury

“…33 Additionally, the severity of the disease results from nonacinar cell mechanisms, including the transmigration and activation of leukocytes within the pancreas and the local synthesis and release of proinflammatory-soluble mediators that transform a local injury into a systemic inflammatory response. [3][4][5][6][7] Based on recent reports stating that PARP-1 plays a relevant role in cell necrosis and organ failure in various diseases associated with inflammation, [15][16][17][18][19] we set out to investigate whether genetic and pharmacological blockade of PARP-1 or PARP-2 (a novel member of the PARP family) might affect the development and severity of pancreatitis in the well-characterized cerulein-induced murine model of acute pancreatitis. This model is characterized by hypermylasemia and hyperlipasemia, extensive acinar cell vacuolization, pancreatic edema, intrapancreatic activation of digestive zymogens including trypsinogen, neutrophils sequestration within the pancreas and varying degrees of acinar cell necrosis.…”

“…24,28 Polymerase chain reaction genotyping screening was performed as described previously. 16,24 The animals were kept under standardized conditions with a 12-h light/ dark cycle. Tap water and mouse chow were provided ad libitum.…”

“…Reduced lung inflammation after PARP inhibition has also been reported in other experimental models of acute inflammatory response. 16,32 Saline-injected mice from all experimental groups showed no morphological evidence of lung injury ( Figure 9). As an additional quantitative assessment of the inflammatory response, lung MPO activity Poly(ADP-ribose) polymerase inhibition in acute pancreatitis RA Mota et al following cerulein-induced pancreatitis was measured.…”

“…3,4,6,[9][10][11][12][13][14] Recently, it has been shown that genetic or pharmacological blockade of the enzyme poly(ADPribose) polymerase-1 (PARP-1) in mice results in a defective inflammatory immune response, associated with abnormalities in the expression of NFkB-dependent genes, such as TNF-a, and IL-6. [15][16][17] This defective response confers on these mice an advantage in different pathophysiological conditions associated with severe inflammation. [15][16][17][18][19] PARP-1 is a highly conserved nuclear zinc-finger DNA-binding protein that specifically detects DNA strand breaks or nicks generated by different genotoxic agents and, using NAD þ as a substrate, synthesizes and transfers ADP-ribose onto aspartic and glutamic acid residues of acceptor proteins involved in chromatin structure and DNA metabolism.…”

“…[15][16][17] This defective response confers on these mice an advantage in different pathophysiological conditions associated with severe inflammation. [15][16][17][18][19] PARP-1 is a highly conserved nuclear zinc-finger DNA-binding protein that specifically detects DNA strand breaks or nicks generated by different genotoxic agents and, using NAD þ as a substrate, synthesizes and transfers ADP-ribose onto aspartic and glutamic acid residues of acceptor proteins involved in chromatin structure and DNA metabolism. 20 The disruption of the PARP-1 gene allowed the discovery of a residual PARP enzymatic activity catalyzed by a novel PARP enzyme known as PARP-2.…”