Metabolic syndrome comprises a cluster of related disorders that includes obesity, glucose intolerance, insulin resistance, dyslipidemia, and fatty liver. Recently, gut-derived chronic endotoxemia has been identified as a primary mediator for triggering the low-grade inflammation responsible for the development of metabolic syndrome. In the present study we examined the role of the small intestinal brush-border enzyme, intestinal alkaline phosphatase (IAP), in preventing a high-fat-diet-induced metabolic syndrome in mice. We found that both endogenous and orally supplemented IAP inhibits absorption of endotoxin (lipopolysaccharides) that occurs with dietary fat, and oral IAP supplementation prevents as well as reverses metabolic syndrome. Furthermore, IAP supplementation improves the lipid profile in mice fed a standard, low-fat chow diet. These results point to a potentially unique therapy against metabolic syndrome in at-risk humans.etabolic syndrome is a complex syndrome composed of a cluster of disorders that includes obesity, glucose intolerance, insulin resistance, abnormal lipid profile (dyslipidemia), fatty liver, and hypertension (1, 2). Metabolic syndrome leads to type 2 diabetes, atherosclerosis, and nonalcoholic fatty liver disease (1, 2). Approximately 35-39% of the US population suffers from the syndrome (3). This epidemic of metabolic syndrome has devastating consequences in terms of mortality, morbidity, and total healthcare expenditures (4).Recently, "metabolic endotoxemia" has been proposed to be central to the pathogenesis of metabolic syndrome. The Gramnegative bacterial cell wall component lipopolysaccharide (LPS) is known as endotoxin, and metabolic endotoxemia is defined as a two-to threefold persistent increase in circulating endotoxin concentrations above the normal levels (5). Metabolic endotoxemia leads to low-grade systemic inflammation as evidenced by increased serum levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1, and IL-6 (5). It is well recognized that chronic inflammation causes damage to pancreatic beta cells (6), hepatocytes (7), and vascular endothelial cells (8), and dysfunction of these cells is thought to contribute to metabolic syndrome.A high-fat diet (HFD) has been shown to cause metabolic endotoxemia in animals and humans (5, 9), but the underlying molecular mechanisms remain incompletely understood. Ghoshal et al. (10) demonstrated that intestinal epithelial cells (enterocytes) internalize LPS from the apical surface, which is then transported to the Golgi apparatus where it complexes with chylomicrons, the lipoproteins that transport the absorbed longchain fatty acids in enterocytes. The chylomicron-LPS complex is then secreted into mesenteric lymph and makes its way into the systemic circulation. Excess chylomicron formation during highfat feeding leads to prolonged chylomicronemia (complexed with LPS) that ultimately induces systemic inflammation. Also, it has been shown that an HFD causes local intestinal inflammation (11). Systemic and local inf...

The intestinal microbiota plays a pivotal role in maintaining human health and well-being. Previously, we have shown that mice deficient in the brush-border enzyme intestinal alkaline phosphatase (IAP) suffer from dysbiosis and that oral IAP supplementation normalizes the gut flora. Here we aimed to decipher the molecular mechanism by which IAP promotes bacterial growth. We used an isolated mouse intestinal loop model to directly examine the effect of exogenous IAP on the growth of specific intestinal bacterial species. We studied the effects of various IAP targets on the growth of stool aerobic and anaerobic bacteria as well as on a few specific gut organisms. We determined the effects of ATP and other nucleotides on bacterial growth. Furthermore, we examined the effects of IAP on reversing the inhibitory effects of nucleotides on bacterial growth. We have confirmed that local IAP bioactivity creates a luminal environment that promotes the growth of a wide range of commensal organisms. IAP promotes the growth of stool aerobic and anaerobic bacteria and appears to exert its growth promoting effects by inactivating (dephosphorylating) luminal ATP and other luminal nucleotide triphosphates. We observed that compared with wild-type mice, IAP-knockout mice have more ATP in their luminal contents, and exogenous IAP can reverse the ATP-mediated inhibition of bacterial growth in the isolated intestinal loop. In conclusion, IAP appears to promote the growth of intestinal commensal bacteria by inhibiting the concentration of luminal nucleotide triphosphates.

Objective To determine the efficacy of oral supplementation of the gut enzyme intestinal alkaline phosphatase (IAP) in preventing antibiotic-associated infections from Salmonella enterica serovar Typhimurium (S. Typhimurium) and Clostridium difficile. Summary background data The intestinal microbiota plays a pivotal role in human health and well-being. Antibiotics inherently cause dysbiosis, an imbalance in the number and composition of intestinal commensal bacteria, which leads to susceptibility to opportunistic bacterial infections. Previously, we have shown that IAP preserves the normal homeostasis of intestinal microbiota and that oral supplementation with calf IAP (cIAP) rapidly restores the normal gut flora. We hypothesized that oral IAP supplementation would protect against antibiotic-associated bacterial infections. Methods C57BL/6 mice were treated with antibiotic(s) +/− cIAP in the drinking water followed by oral gavage of S. Typhimurium or C. difficile. Mice were observed for clinical conditions and mortality. After a defined period of time mice were sacrificed and investigated for hematological, inflammatory and histological changes. Results We observed that oral supplementation with cIAP during antibiotic treatment protects mice from infections with S. Typhimurium as well as C. difficile. Animals given IAP maintained their weight, had reduced clinical severity and gut inflammation, and improved survival. Conclusion Oral IAP supplementation protected mice from antibiotic-associated bacterial infections. We postulate that oral IAP supplementation could represent a novel therapy to protect against antibiotic-associated diarrhea (AAD), C. difficile-associated disease (CDAD), and other enteric infections in humans.

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Peritoneal irrigation with cIAP significantly enhances survival in a mouse model of peritonitis, likely through reduction of local inflammation and remote organ damage. We suggest that intraperitoneal cIAP irrigation could be a novel therapy for intra-abdominal sepsis.

The goal of this study was to compare the effects of Bacillus subtilis and the antibiotic enrofloxacin on growth performance, immune response, intestinal histomorphometry and cecal Salmonella numbers in broilers challenged with S. gallinarum. Salmonella-free chicks (n = 240) were allocated to four groups, comprising six replicates (n = 10) each. Group NN was not infected and received no treatment. Group SN was infected with Salmonella and received no treatment. Group SE was infected with Salmonella and treated with the antibiotic enrofloxacin. Group SP was infected with Salmonella and treated orally with the probiotic B. subtilis. Initially the groups that were infected with Salmonella had reduced growth performance compared with NN. By the fourth week, SE and SP had recovered and weighed as much as or more than NN. The SP group had greater cellular immunity and relative weights of the bursa and thymus than the other groups. SN had the lowest villus height in all the segments of the small intestine and a larger Salmonella population in the ceca. Probiotic supplementation reduced the pathological outcomes more than enrofloxacin. Prophylactic use of B. subtilis-type probiotics had similar effects to the use of antibiotics, alleviated the stress related to infection of S. gallinarum, and improved the growth performance, immune function, and gut mucosal development in broilers. Keywords: growth promoters, immunity, probiotics, poultry villi length

Environmental bacteria have been revealed to be a reservoir of antibiotic resistance genes and a potential pool of novel resistance genes in clinical pathogens. Recently, the soils, which have never been treated with antibiotics before have proved to contain the resistant bacterial strains. In this study, we assessed whether the soil that had not previously been influenced by antibiotics contained super-resistant bacteria or not. We identified super penicillin-resistant strains in four diverse soils containing up to 1000 mg/L penicillin compared to 100 mg/L, but none of super tetracycline resistant strains were detected in four soils containing up to 1000 mg/L tetracycline, which is the highest concentration of exogenous penicillin or tetracycline reported to date. Twenty bacterial isolates were selected, representing a diverse set of species in the genera Pseudomonas (85%) and Variovorax (15%); these bacteria showed multiple antibiotic resistance patterns for four or more antibiotics. Using polymerase chain reaction and sequence, we carefully examined the existence of antibiotic-resistance genes and integron genes in soils and strains. It was observed that the resistance genes tet(C) and blaTEM were fairly widely distributed in these super penicillin-resistant isolates, and 20%-50% of tested genes were found in the study soils. All the study sites provided great opportunities for horizontal resistance transfer. The antibiotic-resistant genes pool, which is potentially large and diverse, may have considerable implications for ecology and health.

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