Abstract
Background: Severe acute pancreatitis (SAP) frequently progresses to pancreatitis-associated multiorgan failure (MOF) with high mortality. Decreased plasma ADAMTS13 activity (ADAMTS13:AC) results in the accumulation of unusually large von Willebrand factor multimers (UL-VWFM) and the formation of platelet thrombi, ultimately leading to MOF. We demonstrated that the imbalance between decreased ADAMTS13:AC and increased UL-VWFM could contribute to SAP pathogenesis through enhanced thrombogenesis, and serve as an early prognostic indicator for SAP patients (Scand J Gastroenterol, 2008, 26:1). Endotoxin has been considered to be the principle activator of the systemic inflammatory response syndrome, which predisposes patients for MOF and/or pancreatic necrosis, ultimately leading to SAP. We investigated the relationship of endotoxin to ADAMTS13:AC and its related parameters, and tried to explore their potential role on the development of MOF in patients with SAP.
Methods: We sequentially determined plasma endotoxin concentration, ADAMTS13:AC and its related parameters in 13 SAP patients (APACHE-II score mean 6.6 ± 2.7), who were admitted into intensive care unit of our hospital between 2004 and 2006. Eleven patients were survivors and two were non-survivors whose APACHE II scores were 10 and 12 died of MOF, respectively. The degree of MOF was evaluated according to the SOFA score. Endotoxin concentration was determined by a chromogenic substrate assay (Toxicolor LS –M Set, Seikagaku Kogyo Co.) with kinetic analysis after pretreatment with detergent, Triton X-100, and heating at 70 °C for 10 min. Plasma ADAMTS13:AC was determined by a sensitive chromogenic ELISA (ADAMTS13-act-ELISA: Kainos Inc.). Plasma UL-VWFM was analyzed by a vertical SDS-1.0% agarose gel electrophoresis. Plasma VWF antigen (VWF:AG), interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor -α (TNF-α) were measured by ELISA.
Results: In normal healthy controls (n=20), plasma endotoxin concentration was 7.9±1.7 pg/ml (mean ± SD). The concentration in the SAP patients significantly increased at day 1 (means 65 pg/ml, p<0.001) and at day 2 (88 pg/ml, p<0.001) as compared to healthy controls. The values, thereafter, gradually decreased in 8 survivors (55 pg/ml at day 5, 53 pg/ml at day 7, 27 pg/ml at day 14), while in remaining 3 survivors needing necrosectomy, the concentration further increased (98 pg/ml at day 5, 178 pg/ml at day 7), and decreased to 20 pg/ml at day 14 at the recovery phase. In two non-survivors, the endotoxin levels increased from 37 pg/ml at day 1 to 462 pg/ml at day 2 in one needing necrosectomy, and showed 51 pg/ml at day 1 in another at the age of 91. Within 1 or 2 days after admission, the ADAMTS13:AC was lower in SAP patients (mean 29%, p<0.001) than in healthy controls (99%), and gradually recovered in the 11 survivors but further decreased in the 2 non-survivors. On admission, VWF:Ag was higher (402%, p<0.001) in SAP patients than controls (100%). VWF:Ag gradually decreased in the survivors, except in the 3 survivors needing a necrosectomy, but remained high in the non-survivors. UL-VWFM positive patients showed lower ADAMTS13:AC (25% vs. 42%, p<0.05) and higher VWF:Ag ( 481% vs. 332%, p<0.05), resulting in higher ratio of VWF:Ag to ADAMTS13:AC (25.2 vs. 9.1, p<0.02), as compared to UL-VWFM negative ones. Patients with higher endotoxin concentration more than 50 pg/ml showed lower ADAMTS13:AC than those without (22% vs. 43%, p<0.05). Plasma endotoxin concentration positively correlated with the ratio of VWF:Ag to ADAMTS13:AC (r=0.732, p<0.005). The SOFA score correlated positively with plasma endotoxin concentration (r=0.604, p<0.03), IL-8 (r=0.843, p<0.001), and the ratio of VWF:Ag to ADAMTS13:AC (r=0.700, p<0.01), and inversely with the ADAMTS13:AC (r= − 0.601, p<0.03).
Conclusion. The imbalance between decreased ADAMTS13:AC and increased UL-VWFM is closely related to enhanced endotoxemia, which may contribute to the development of SAP and subsequent MOF through enhanced thrombogenesis.
Clinical Profile and Outcome of Patients with Severe Acute Pancreatitis
