Bovine Intestinal Alkaline Phosphatase Attenuates the Inflammatory Response in Secondary Peritonitis in Mice

Abstract

Lipopolysaccharide (LPS) contributes importantly to morbidity and mortality in sepsis. Bovine intestinal alkaline phosphatase (BIAP) was demonstrated to detoxify LPS through dephosphorylation. LPS injection combined with BIAP reduced inflammation and improved survival in various experimental settings. In this study, single-dose intravenous administration of BIAP (0.15 IU/g) was applied in a murine cecal ligation and puncture (CLP) model of polymicrobial sepsis. Saline was given as control (S group). Treatment with BIAP prior to CLP (prophylaxis; BIAP-P group) or shortly after (early treatment; BIAP-ET group) reduced cytokine concentrations in plasma and peritoneal lavage fluid (PLF). Tumor necrosis factor-alpha peak levels decreased from 170 pg/ml (S) to 57.5 (BIAP-P) and 82.5 (BIAP-ET) in plasma and in PLF from 57.5 pg/ml (S) to 35.3 (BIAP-P) and 16.8 (BIAP-ET) (all, P < 0.05). Peak interleukin-6 levels in plasma decreased from 19.3 ng/ml (S) to 3.4 (BIAP-P) and 11.5 (BIAP-ET) and in PLF from 32.6 ng/ml (S) to 13.4 (BIAP-P) and 10.9 (BIAP-ET) (all, P < 0.05). Macrophage chemoattractant protein 1 peak levels in plasma decreased from 2.0 ng/ml (S) to 1.0 (BIAP-P) and 0.7 (BIAP-ET) and in PLF from 6.4 (S) to 2.3 (BIAP-P) and 1.3 ng/ml (BIAP-ET) (all, P < 0.05). BIAP-treated groups showed decreased transaminase activity in plasma and decreased myeloperoxidase activity in the lung, indicating reduced associated hepatocellular and pulmonary damage. Survival was not significantly altered by BIAP in this single-dose regimen. In polymicrobial secondary peritonitis, both prophylactic and early BIAP treatment attenuates the inflammatory response both locally and systemically and reduces associated liver and lung damage.Secondary peritonitis can ultimately lead to sepsis with shock and/or organ failure and is associated with high morbidity and mortality (30 to 40%) (5). Both secondary peritonitis and sepsis are characterized by an excessive inflammatory response (7, 28). Activation of cytokines and other inflammatory mediators in these conditions are induced by endotoxins, such as lipopolysaccharide (LPS), which is an important contributor to morbidity and mortality (28). LPS is a component of the outer leaflet of gram-negative bacteria. It is a complex and negatively charged molecule composed of a polysaccharide chain (O-specific chain) and a toxic lipid moiety (lipid A). The two phosphate groups of lipid A are essential for its immunostimulatory characteristics (2, 7). Intravenous (i.v.) injection of LPS leads to a generalized inflammatory response (29). The dephosphorylation product of lipid A, monophosphoryl lipid A, is a nontoxic derivative that does not evoke major inflammatory response (2) and is known to induce tolerance (1, 34). Therefore, LPS (and, in particular, lipid A) is a potential therapeutic target in sepsis (7, 11). Many sepsis therapies have aimed to block the effect of LPS by using antisera (6, 35) and anti-LPS antibodies (20) or by binding LPS with LPS-binding protein (8) or high-density lipoprotein (1...

Intestinal alkaline phosphatase promotes gut bacterial growth by reducing the concentration of luminal nucleotide triphosphates

“…Pharmacologically, IAP has been found to be an effective therapy against various human as well as animal disease models including IBD, necrotizing enterocolitis, gram-negative sepsis, C. difficile, and S. typhimurium infections, and metabolic syndrome (1,21,34,44,56,58,61). Clinical trials using bovine IAP against colitis have shown that IAP has no or minimal side effects (34).…”

The Mucin Muc2 Limits Pathogen Burdens and Epithelial Barrier Dysfunction during Salmonella enterica Serovar Typhimurium Colitis

“…Recently there has been renewed interest in IAP activity and its role in promoting intestinal mucosal defense (15). Several studies have shown that LPS dephosphorylation mediated by IAP protects the host against LPS-induced inflammation as well as reducing the systemic translocation of enteric bacteria (15)(16)(17)(18)(19)(20)(21)(22)(23)(24). To investigate whether IAP activity was playing a role in the increased susceptibility/morbidity of Muc2 Ϫ/Ϫ mice in our model, we stained for IAP and found that Muc2 Ϫ/Ϫ mice had reduced IAP expression as well as reduced LPS dephosphorylation activity (a measure of the activity of IAP) within their cecal tissues.…”

“…Furthermore, IAP-mediated LPS detoxification plays a role in preventing systemic translocation of LPS across the intestinal barrier (15)(16)(17)(18)(19)(20)(21). In the absence of this detoxification, systemic translocation of LPS triggers exaggerated inflammatory responses that can ultimately prove fatal to the host through proinflammatory cytokine-induced septic shock (22,23,24).…”

Prophylactic Treatment with Alkaline Phosphatase in Cardiac Surgery Induces Endogenous Alkaline Phosphatase Release

“…In previous animal studies, promising therapeutic effects have been shown in reducing the inflammatory response with the use of intravenous alkaline phosphatase (9)(10)(11). In a clinical study in severe sepsis patients, continuous infusion of calf-intestinal alkaline phosphatase significantly improved renal function (12,13).…”