[Proton-pump inhibitor use and hyponatremia].

AIM: Proton-pump inhibitors (PPIs) are widely used. However, reports of their adverse effects are increasing. Older patients are prone to developing hyponatremia due to various factors. The special environment of a geriatric healthcare facility tends to subject these patients to long-term medication use. Therefore, we hypothesized that nursing home residents receiving PPIs will present hyponatremia. METHODS: The residents of Shonan Silver Garden, a long-term care health facility for older adults, were divided into two groups: a control group (n=61) which did not receive proton-pump inhibitors and a PPI group (n=29), which received proton-pump inhibitors for at least 6 months. The PPI group was further divided into the lansoprazole group (LPZ group) and the other PPI group. Other PPI users were excluded due to small numbers. The blood test results were compared between the control and LPZ groups. In the LPZ group, blood samples were taken 1 month after the discontinuation of lansoprazole, and serum Na level was compared to the level before discontinuation. RESULTS: Blood Na levels in the PPI were lower than those in the control group, and hyponatremia (<136 mEq/L) was more frequent in the LPZ group than in the control group. There were no significant differences in other blood test parameters between the control and LPZ groups. At one month after the discontinuation of lansoprazole, serum Na levels were significantly increased; however, they remained lower than those in the control group. CONCLUSION: A higher rate of hyponatremia was induced in older residents of long-term care facilities who took lansoprazole for >6 months in comparison to those who did not take lansoprazole.

Plasma thrombin activatable fibrinolysis inhibitor and tissue factor pathway inhibitor changes following sepsis.

Sepsis-induced systemic inflammation results in coagulation abnormalities that may be different in gram-positive and gram-negative infections. We used ciprofloxacin to induce a predominantly gram-positive Enterococcus faecalis polymicrobial sepsis in rats. Ciprofloxacin-untreated rats exhibited a predominantly gram-negative polymicrobial sepsis. Rats were subjected to 30% body surface area burn (B), cecal ligation puncture (CLP) with a 22-gauge needle, and B + CLP. Ciprofloxacin-treated B + CLP rats showed a significant decrease in plasma thrombin activatable fibrinolysis inhibitor (TAFI) levels compared with sham rats. However, plasma tissue factor pathway inhibitor (TFPI) levels decreased significantly in B, CLP, and B + CLP groups compared with sham rats. The ciprofloxacin-untreated group showed a significant decrease in plasma TAFI levels in CLP and B + CLP and plasma TFPI levels decreased in all 3 groups compared with sham rats. Histological changes in the liver and kidney included vascular congestion and parenchyma bleed following B + CLP in ciprofloxacin-untreated rats. These results suggest that plasma TAFI and TFPI levels differ depending on the type of bacteria involved in the septic process.

Effect of acute alcohol ingestion prior to burn injury on intestinal bacterial growth and barrier function.

Previous studies from our laboratory have shown that acute alcohol (EtOH) ingestion prior to burn injury enhances intestinal bacterial translocation. This study tested if increased intestinal bacterial translocation in alcohol and burn injured rats is due to an overgrowth in intestinal bacteria. We determined if the translocation was accompanied with alterations in intestinal permeability and immune cell population. Rats (225-250 g) were gavaged with alcohol to achieve a blood EtOH level in the range of 100 mg/dl prior to burn or sham injury (25% total body surface area). Two days after injury, we found that acute alcohol ingestions prior to burn injury results in a significant increase in bacterial counts in small intestine. The increase in intestinal bacterial counts accompanied a significant increase in intestinal permeability. Finally, immunohistochemical analysis revealed a substantial (p<0.05) loss of both T cell and dendritic cells in intestine of alcohol and burn injured rats compared with intestine of rats receiving either burn or sham injury. Altogether, results presented in this manuscript suggest that increase in intestinal bacterial growth along with alterations in intestinal permeability and immune status contribute to the increase in bacterial translocation observed in alcohol and burn injured rats.

Differential induction of hepatic dysfunction after intraportal and intravenous challenge with endotoxin and Staphylococcal enterotoxin B.

We have previously shown that systemic infusion of the bacterial toxins Staphylococcal enterotoxin B (SEB) and endotoxin (LPS) induces hepatic dysfunction as measured by decreased biliary indocyanine green (ICG) excretion. In this study, we compare the effects of these bacterial toxins after infusion into the portal and systemic circulation and directly measure biliary bile acid excretion as a measure of cholestasis. We hypothesized that bacterial toxins infused into the portal vein would induce greater hepatic dysfunction than toxins infused into the systemic circulation. Using a chronically catheterized rat model, biliary bile acid excretion was directly measured after infusion of LPS at 10 and 100 microg/kg with and without 50 microg/kg SEB into the portal vein (IPV) or inferior vena cava (IV) at baseline, and at 6 and 24 h. We found that when LPS was infused alone, only IPV administration caused a significant decrease in bile acid excretion at 6 h. There was no change in bile acid excretion after IV administration of LPS. In contrast, when the combination of LPS and SEB was infused, both IV and IPV administration significantly decreased bile acid excretion at 6 and 24 h. At 6 h post-LPS and -SEB administration, the decrease in bile acid excretion was significantly greater after IPV than IV administration. There was no site-specific difference in IFN-gamma release after infusion of toxins. However, peak TNFalpha release was decreased in IPV-infused rats [10 microg/kg (P < 0.05) or 100 microg/kg (P = ns) LPS with SEB] compared with the same doses in IV-infused rats. These data question the role of systemic TNF-alpha and IFN-gamma in regulating hepatic dysfunction and suggest a differential functional response of the liver to systemic and gut-derived septic events. This study also further explains the frequent development of liver dysfunction in patients with sepsis, multisystem organ failure, and other diseases with altered intestinal permeability.

Enterococcus faecalis exacerbates burn injury-induced host responses in rats.

Pathophysiology of burn injury with complications of gram-positive infections is not well characterized. We have developed an in vivo rat model to study the effects of burn injury along with intra-abdominal inoculation of Enterococcus faecalis. We hypothesized that although burn injury or E. faecalis inoculation by itself may not induce significant pathophysiological responses, the combination of the two can lead to adverse pathophysiological consequences. Sprague-Dawley rats were divided into 4 groups: group 1(C), controls; group 2(B), burn injury on 30% total body surface area; group 3(EF), intra-abdominal implantation of bacterial pellet impregnated with E. faecalis; group 4(B+EF), burn injury plus bacterial pellet implantation. The mortality was 25% and 60% on day 1 and 2 in Group 4(B+EF), respectively; no significant mortality was observed in other groups. In group 4(B+EF), metabolic acidosis, respiratory alkalosis, and a hyperdynamic state developed on day 1, and metabolic and respiratory acidosis and a hypodynamic state on day 2. There were no significant alterations in metabolic or hemodynamic measurements in other groups. Intestinal microvascular permeability to albumin on day 1 and 2 was increased in group 4(B+EF). In group 2(B), microvascular permeability was not increased significantly. Although the permeability was increased on day 1 in group 3(EF), it declined on day 2. The metabolic and hemodynamic alterations were correlated with increased intestinal microvascular permeability to albumin. E. faecalis appeared to be involved in initiating a vicious cycle of burn injury-mediated disruption of intestinal integrity along with metabolic and hemodynamic derangements.

Tissue factor pathway inhibitor and thrombin activatable fibrinolytic inhibitor plasma levels following burn and septic injuries in rats.

Burn and septic injuries induce profound changes in coagulation status. This study examined the changes in plasma tissue factor pathway inhibitor (TFPI) and thrombin activatable fibrinolytic inhibitor (TAFI) levels in a rat model of burn and septic injuries. Rats underwent 30% TBSA cutaneous scald burn injury and septic insult was induced by caecal ligation and puncture (CLP). CLP was superimposed on burn injury to mimic the clinical model of sepsis complicating burn injury. Rats were pretreated with Cprofloxacin orally to colonize their gut with Enterococcus faecalis. TFPI and TAFI plasma levels were measured using functional activity assay kit with a chromogenic method at 24 and 72 hours following the injuries. TFPI levels decreased significantly at 24 hours in burn, CLP, and burn+CLP groups, followed by incomplete rebound recovery at 72 hours in all three groups. On the other hand, TAFI levels increased significantly at 24- and 72-hour time points in all three groups. These results suggest that burn, septic, and their combined injuries perturb coagulation cascade and thrombotic process toward the procoagulant pathway by impairing fibrinolysis.

Burn injury exacerbates hemodynamic and metabolic responses in rats with polymicrobial sepsis.

The most common and life-threatening complication of severe burn injury is infection, which often results in multiple organ failure (MOF). However, the mechanism of development of MOF after burn injury associated with infection is not fully understood. Our previous studies showed that when polymorphonuclear neutrophils (PMNs) are depleted, burn injury-induced increase in microvascular permeability to albumin is markedly attenuated. Thus, we hypothesized that the combination of burn injury and polymicrobial infection exacerbates PMN activation, increases intestinal microvascular permeability to albumin, and alters hemodynamics and metabolism more than burn injury or infection alone. Sprague-Dawley rats (250-275 g) were divided into four groups. In the burn group, rats were subjected to a 30% TBSA burn injury. In the cecal-ligation puncture (CLP) group, CLP was performed using a 22-gauge needle with one puncture. In burn+CLP group, rats were subjected to CLP immediately after burn procedure. In sham group, rats were subjected to sham procedures. Transient polymicrobial bacteremia and persistent polymicrobial bacteremia were induced in the CLP group and burn+CLP group, respectively. Microvascular permeability, myeloperoxidase, and PMN production of elastase and reactive oxygen species increased in the burn group and CLP group and further increased in the burn+CLP group. Hemodunamic and metabolic alterations on day 1 and 3 after injury correlated with those alterations. Although there was only a low mortality in the burn group and CLP group, there was a high mortality in burn+CLP group (79%). The mechanism of MOF that leads to high mortality in burn injury complicated by infection may involve uncontrolled microvascular damage mediated by PMN activation.

LPS-induced changes in myocardial markers in neonatal rats.

Lipopolysaccharide (LPS) produces varied systemic metabolic effects. We studied the effects of LPS on the cardiac fatty acid profile and its relationship to energy metabolism and inflammatory mediators that included TNF-alpha and nitric oxide synthase (NOS) in 10-day-old neonatal rat pups. Rat pups received an i.p. injection of LPS after a 4-hour starvation period, followed by collection of blood and cardiac tissue 4 h following LPS administration. Compared to controls, LPS induced significant hypoglycemia and hyperlactacidemia, suggesting the development of endotoxic shock. The result was a significant depression in total fatty acid levels as well as non-esterified fatty acid in the cardiac tissue of the LPS-treated pups. In addition, LPS-treated pups also showed a significant increase in TNF-alpha, NOS levels with a depressed redox state and energy metabolism in cardiac tissue. These observations suggest that endotoxic shock in 10-day-old rat pups induces a systemic inflammatory response with a depression in fatty acid metabolism that may contribute to myocardial failure.

Gut-associated lymphoid T cell suppression enhances bacterial translocation in alcohol and burn injury.

The mechanism of alcohol-mediated increased infection in burn patients remains unknown. With the use of a rat model of acute alcohol and burn injury, the present study ascertained whether acute alcohol exposure before thermal injury enhances gut bacterial translocation. On day 2 postinjury, we found a severalfold increase in gut bacterial translocation in rats receiving both alcohol and burn injury compared with the animals receiving either injury alone. Whereas there were no demonstrable changes in intestinal morphology in any group of animals, a significant increase in intestinal permeability was observed in ethanol- and burn-injured rats compared with the rats receiving either injury alone. We further examined the role of intestinal immune defense by determining the gut-associated lymphoid (Peyer's patches and mesenteric lymph nodes) T cell effector responses 2 days after alcohol and burn injury. Although there was a decrease in the proliferation and interferon-gamma by gut lymphoid T cells after burn injury alone; the suppression was maximum in the group of rats receiving both alcohol and burn injuries. Furthermore, the depletion of CD3(+) cells in healthy rats resulted in bacterial accumulation in mesenteric lymph nodes; such CD3(+) cell depletion in alcohol- and burn-injured rats furthered the spread of bacteria to spleen and circulation. In conclusion, our data suggest that the increased intestinal permeability and a suppression of intestinal immune defense in rats receiving alcohol and burn injury may cause an increase in bacterial translocation and their spread to extraintestinal sites.

Chronic Staphylococcal enterotoxin B and lipopolysaccharide induce a bimodal pattern of hepatic dysfunction and injury.

OBJECTIVE: To determine the effect of chronic exposure to endotoxin (lipopolysaccharide) and Staphylococcal enterotoxin B on hepatic injury and function. DESIGN: Prospective, controlled trial. SETTING: Research laboratory in a university hospital. SUBJECTS: Male Sprague-Dawley rats weighing 325-350 g with chronic vascular and bile catheters. INTERVENTIONS: Chronically catheterized rats were treated daily with saline, 50 microg/kg Staphylococcal enterotoxin B alone, 1000 microg/kg lipopolysaccharide alone, 1000 microg/kg lipopolysaccharide with 50 microg/kg Staphylococcal enterotoxin B, or 100 microg/kg lipopolysaccharide with 50 microg/kg Staphylococcal enterotoxin B for 10 days. Serum and biliary measures of hepatic injury and dysfunction were measured before and then 6 hrs and 1, 2, 3, 7, and 10 days after the start of treatment. The animals were killed at 10 days and the livers examined histologically. MEASUREMENTS AND MAIN RESULTS: Mean rates of bile flow, biliary indocyanine green excretion, and bile acid flux were significantly decreased immediately after treatment (6 hr, 1 and 2 days) and then at 10 days. Increases in biliary and serum gamma-glutamyltransferase and serum bile acids also occurred in a similar bimodal pattern. Animals treated with lipopolysaccharide or Staphylococcal enterotoxin B alone became tolerant and did not develop the bimodal pattern of hepatic dysfunction. Histologic examination of the liver at 10 days revealed periportal inflammation and fibrosis. CONCLUSIONS: The combination of lipopolysaccharide and Staphylococcal enterotoxin B leads to late liver injury, whereas either toxin alone does not. These data may explain the frequent development of liver dysfunction in patients exposed to multiple bacterial toxins such as in sepsis, multiple-system organ failure, and other diseases with altered intestinal permeability.

Exacerbation of intestinal permeability in rats after a two-hit injury: burn and Enterococcus faecalis infection.

OBJECTIVE: To determine alterations in intestinal epithelial permeability to solutes in burn injured rats with and without Enterococcus faecalis infection and the role of neutrophils in the intestinal permeability changes. DESIGN: Prospective sham-controlled animal study. SETTING: University research laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Rats were subjected to 30% total body surface burn (B group), E. faecalis infection (EF group) induced via intra-abdominal implantation of bacterial pellet, or combination of burn injury and E. faecalis infection (B+EF group). MEASUREMENTS AND MAIN RESULTS: In vivo measurements of intestinal permeability were carried out after intraluminal injection of H lactulose and C mannitol in the ileum of sham, B, EF, and B+EF groups of rats, 1 and 2 days after injury. Lactulose permeability was increased in the injured rat groups (B, EF, B+EF) on day 1 postinjury compared with sham. The combined injury group (B+EF) had the highest level of lactulose permeability. Although a significant change in lactulose permeability from day 1 to day 2 postinjury could not be demonstrated in the B and EF groups, lactulose permeability in the B+EF group on day 2 postinjury markedly decreased from day 1 but was still significantly higher than that in the sham group. Mannitol permeability was increased in all injured rat groups on day 1 postinjury; on day 2 it remained elevated post-B, decreased post-EF, and further increased after B+EF. Ex vivo measurements of lactulose movements across intestinal epithelial monolayers (IEC-18) were carried out in the presence of blood neutrophils from sham, B, EF, or B+EF rats. We also measured ex vivo transepithelial migration of neutrophils from sham, B, EF, or B+EF rat groups. Neither the transepithelial lactulose movement in the presence of neutrophils from, nor neutrophil migration in, the B or EF rats was significantly different from sham. However, a significant increase in transepithelial lactulose movement and neutrophil migration occurred in the B+EF group. Immunoblot analyses and in situ histochemical localizations of intestinal tight junction proteins, occludin and claudin-3, showed decreases in the distribution of occludin but not claudin-3 in the B, EF, and B+EF groups. CONCLUSIONS: Alterations in intestinal solute permeability and disruption of tight junction integrity after a two-hit injury with burn and E. faecalis infection, but not after individual injuries of burn or E. faecalis infection, are likely associated with heightened neutrophil flux across the intestinal epithelium.