Multiple systems organ failure

Intra-abdominal high pressure induces intestinal barrier dysfunction in rats

AIM: To study the effect of different degrees of intra-abdominal high pressure on intestinal mucosal barrier dysfunction and to explore the possible mechanisms involved.

METHODS: Forty-five adult male SD rats were randomly divided into a normal control group, a 10 mmHg and a 20 mmHg group (n = 15 for each). Nitrogen pneumoperitoneum was induced to generate intra-abdominal high pressure in animal models. The two pneumoperitoneum groups were further divided into three subgroups (five rats in each subgroup) for testing when pneumoperitoneum was maintained for 1, 2 and 4 h, respectively. Twenty-four hours after the relief of pneumoperitoneum, a spectrophotometer was used to measure the concentration of blue dextran 2000 in different segments of the small intestine. Malondialdehyde (MDA), reduced glutathione (GSH) and superoxide dismutase (SOD) in intestinal tissue homogenates, as well as plasma diamine oxidase (DAO) and D-lactic acid were measured. Morphological changes in the intestinal tissue were observed by light microscopy and electron microscopy.

RESULTS: Compared to the control group, intestinal transit was significantly delayed, but intestinal SOD, GSH and MDA levels and plasma D-lactate level showed no significant changes in the two high intra-abdominal pressure groups (all P > 0.05). Plasma DAO level did not differ significantly between the 10 mmHg group and control group, but was significantly different between the 20 mmHg and control groups (1412.93 ± 1397.19 vs 542.41 ± 314.93, P < 0.05). Under the light microscope, postoperative intestinal mucosa showed no damage in the control group; however, mild (increase in small intestinal subepithelial gaps and villus capillary congestion) and severe (varying degrees of intestinal mucosal changes, small intestinal mucosal congestion and edema, expansion of small intestinal subepithelial gaps, and intestinal villus degeneration, necrosis or loss) pathological changes were observed in the 10 and 20 mmHg groups, respectively. Electron microscopy demonstrated that intestinal villus cells in the 10 mmHg group showed mild swelling of tight junctions, and the 20 mmHg group showed significant changes in the microvillus and mitochondrial structures.

CONCLUSION: High intra-abdominal pressure can delay intestinal transit, alter plasma DAO activity, cause significant damage to intestinal epithelial cells, and increase intestinal permeability.

Effects of Crude Rhubarb on Intestinal Permeability in Septic Patients

The therapeutic effect of crude rhubarb on intestinal permeability was investigated in septic patients. Forty septic patients were enrolled in this study and randomly divided into two groups: the crude rhubarb treatment group ( n = 18) and the control group ( n = 22). The same treatments were given to both groups except that the crude rhubarb treatment group was administrated with crude rhubarb powders (3 g, tid, p.o). The levels of procalcitonin, D-lactate in plasma and lactulose/mannitol (L/M) ratio in the urine were determined on the first day and the sixth day after treatment with or without crude rhubarb. There were no significant differences in procalcitonin, L/M ratio and D-lactate on the first day between the crude rhubarb treatment group and the control group ( p > 0.05). However, the ratio of L/M on the sixth day for the control group was 0.167 ± 0.036, while that of the crude rhubarb treatment group was 0.062 ± 0.013 ( p < 0.05). Moreover, the levels of procalcitonin and D-lactate in the crude rhubarb treatment group were obviously lower than those in the control group on the sixth day (procalcitonin: 4.11 ± 1.40 μg/L vs. 2.21 ± 0.61 μg/L ; D-lactate: 0.24 ± 0.06 ng/L vs. 0.09 ± 0.03 ng/L , p < 0.05, both). These data confirmed that crude rhubarb's effects on septic patients of ameliorating intestinal permeability.

The effect of morphine on mast cell-mediated mucosal permeability

BACKGROUND

The late phase of post-traumatic multisystem organ failure is associated with sepsis from organisms that normally reside within the gut's lumen. Morphine, a commonly employed analgesic in injured patients, is associated with intestinal stasis, bacterial overgrowth, and translocation when administered to rats. N-formyl-methionyl-leucyl-phenylalanine (FMLP), a toxic product of gram-negative organisms, provokes an increase in mucosal permeability when infused into the ileal lumen of this species. The current study was designed to examine the effects of morphine on FMLP perturbation of the mucosal barrier of the ileum of rats and mice to an impermeant macromolecule, dextran 4400. The potential role of mucosal mast cells in the response to either agent alone or in combination was examined.

METHODS

Intact and isolated segments of distal ileum of naïve and sensitized (Trichinella spiralis and egg albumin) Sprague-Dawley rats were exposed to FMLP with or without morphine or doxantrazole, a mast cell-stabilizing agent. Isolated segments of distal ileum of mast cell-deficient mice also were studied.

RESULTS

Mucosal exposure of distal ileal mucosa (intact and isolated, and naive and sensitized) to FMLP was associated with an increase in permeability to dextran 4400, which was completely ablated by morphine and doxantrazole. Sensitization was associated with a prolongation of the FMLP response. Ilea of mast cell-deficient mice (but not their wild type litter mates) were unresponsive to FMLP.

CONCLUSIONS

Morphine antagonizes the provocative effect of FMLP on the mucosal barrier to dextran 4400 of the ilea of rats and mice. Intestinal mucosal mast cells play a central role in the process.

Amelioration of intestinal reperfusion injury by moderate hypothermia is associated with serum sICAM-1 levels

BACKGROUND

The aim of this study was to investigate the effects of moderate hypothermia on various serum markers involving in inflammation after intestinal ischemia-reperfusion (IR).

MATERIALS AND METHODS

The model of 30 min intestinal ischemia +90 min reperfusion was used. Three groups of rats were studied, n=7-8 per group: 1) sham at normothermia, 36.5 to 37.5 degrees C; 2) IR at normothermia and; 3) IR at moderate hypothermia, 32 to 33 degrees C. Serum levels of TNF-alpha, lipopolysaccharide-inducible CXC chemokine (LIX), and soluble intercellular adhesion molecule-1 (sICAM-1) were determined using ELISA technique. Histological features of terminal ileum were also graded.

RESULTS

Intestinal IR at normothermia caused remarkable tissue injury together with an elevation in serum TNF-alpha, LIX, and sICAM-1 levels. Moderate hypothermia significantly decreased the degree of mucosal damage and attenuated the elevation of serum sICAM-1 levels. However, there were no significant differences in serum TNF-alpha and LIX levels between IR at normothermia and IR at hypothermia.

CONCLUSIONS

Intestinal IR at normothermia induces the elevation of serum TNF-alpha, LIX, and sICAM-1 levels. Moderate hypothermia protects the small intestine from reperfusion injury. This beneficial effect is associated with serum sICAM-1 levels but not with serum TNF-alpha and LIX levels. We speculate that one of the mechanisms, by which hypothermia blunts the tissue injury, is at the step of firm adhesion between leukocytes and endothelial cells.

Mechanisms of postburn intestinal barrier dysfunction in the rat: Roles of epithelial cell renewal, E-cadherin, and neutrophil extravasation*

OBJECTIVE

Our group has previously shown that the intestinal epithelium exhibits increased postburn barrier permeability and bacterial translocation associated with deranged neutrophil activity. The purpose of this investigation is to explore possible underlying intestinal structural mechanisms, leading to those functional changes with emphasis on (1) neutrophil influx and extravasation in the intestinal lamina propria 1-3 days after burn and (2) enterocyte proliferation, migration, apoptosis, and E-cadherin junctional epithelium levels 3 days after burn.

DESIGN

Freshly isolated ileum specimens were quick frozen, then cut by a cryostat into 30-micron-thick sections. Sections from day 1 postburn rats were immunostained with (1) anti-granulocyte or anti-elastase antibodies to assess neutrophil influx or (2) combined anti-granulocyte and anti-von Willebrand factor double immunolabeling to compare levels of neutrophil extravasation. Sections from day 3 postburn rats were immunostained with (1) bromodeoxyuridine immunohistochemistry 1, 3, 6, or 18 hrs after bromodeoxyuridine injection to assess enterocyte proliferation and migration, (2) cytokeratin-18 M30-immunohistochemistry to compare levels of enterocyte apoptosis, and (3) E-cadherin immunohistochemistry to compare junctional E-cadherin integrity. Ileal myeloperoxidase activity and bacterial translocation of Enterococcus faecalis were assessed biochemically and by E. faecalis-specific bacterial cultures, respectively, in day 3 postburn rats.

SETTING

: Research laboratories in a medical center and an academic institution.

SUBJECTS

Male Sprague-Dawley rats given sham treatment or treatment as a burn model with full-thickness skin scald over 30% total body surface area.

CONCLUSIONS

We report (1) increased levels of neutrophil influx and extravasation in villi lamina propriae, including elastase-positive cells (postburn day 1), (2) heightened levels of intestinal myeloperoxidase activity (postburn day 3), (3) decreased levels of epithelial cell proliferation, migration, and E-cadherin (postburn day 3), and (4) increased enterocyte apoptosis and E. faecalis bacterial translocation (postburn day 3). Based on these structural and functional abnormalities, we propose a mechanism for burn injury-related intestinal barrier dysfunction that includes increased trans- and para-cellular leakage caused by impaired enterocyte renewal and decreased junctional E-cadherin levels subsequent to increased neutrophil influx and extravasation within the villus lamina propria microenvironment.

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Neutrophil depletion prevents intestinal mucosal permeability alterations in burn-injured rats

Cutaneous thermal injury increases intestinal mucosal permeability. The mechanisms of this functional disturbance are not fully understood. We investigated whether accumulation of neutrophils in the intestine contributes to the increase in mucosal permeability. Labeled and unlabeled lactulose and mannitol were infused into a segment of rat ileum or jejunum. Blood concentrations of [(3)H]lactulose and [(14)C]mannitol were measured after 30, 60, and 90 min. On day 1 postburn, lactulose permeability increased fourfold in the ileum and twofold in the jejunum compared with sham-burned rats; mannitol permeability increased twofold in the ileum and 1. 5-fold in the jejunum. A greater increase in permeability occurred on day 3 postburn in the ileum, but not in the jejunum. The depletion of neutrophils in burned rats prevented the increase in permeability in both segments on day 1 postburn. Histological studies of intestines from burned, with or without neutrophil depletion, and sham-burned rats showed similar morphology. However, numerous neutrophils were found in the extravascular compartment in day 1 postburn, but not in neutrophil-depleted and sham-burned rats. These findings support the concept that the burn-induced increase in mucosal permeability is produced during the accumulation of neutrophils in the intestine and can be abrogated by the depletion of neutrophils.

Multiple organ dysfunction in ulcerative colitis

OBJECTIVE

The mortality rate in severe ulcerative colitis (UC) is commonly attributed to major colonic complications or surgical procedures. Early recognition of the severity of the colitis, intensive medical treatment, and prompt surgery have all contributed to improving its outcome over the past 40 yr. Recently, we have observed some fatal cases of severe UC in which death was related to multiple organ dysfunction syndrome (MODS). This complication, associated with a very high mortality rate, may occur in several acute critical diseases, both infectious and noninfectious, but has so far not been reported in UC. The aim of this study was to evaluate the prevalence and outcome of MODS in severe UC.

METHODS

The records of 180 consecutive patients admitted to the Gastrointestinal Unit, University of Rome for an acute severe attack of UC during the period 1976-1998 were retrospectively analyzed. Severity of UC was defined according to the criteria of Truelove and Witts. MODS was defined according to the original criteria of the American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference 1992. All patients were on a standard intensive regimen consisting of total parenteral nutrition and hydrocortisone 100 mg q.i.d. Colectomy was performed according to the timing of the Oxford intensive regimen.

RESULTS

Of these 180 severe UC patients, 11 (6.1%) experienced clinical and laboratory features of MODS. The lung was involved in five patients, the kidney in three, the liver in seven, the central nervous system in three, the hematological system in three, and the pancreas in one. MODS was preceded by toxic megacolon in five patients and by so-called "impending megacolon" in four, whereas in two patients no previous complications of UC were observed. MODS developed during the first attack of colitis in seven patients and during relapse in four. The overall mortality rate was 12/180 (6.6%). Of the 12 patients who died, eight (72.7%) had MODS.

CONCLUSIONS

These data indicate that UC must be included among the causes of MODS. In our referral center for inflammatory bowel diseases, MODS was responsible for the majority of UC cases with a fatal outcome. The timely identification of signs of MODS should prompt admission to an intensive care unit and emergency surgery.

Pulmonary function and radiographic abnormalities related to neurological outcome after aneurysmal subarachnoid hemorrhage

OBJECT

This observational study is based on a consecutive series of 207 patients with aneurysmal subarachnoid hemorrhage who were treated within 7 days of their most recent bleed. The purpose of the study was to evaluate the effect of respiratory failure on neurological outcome.

METHODS

Pulmonary function was assessed by determination of parameters describing pulmonary oxygen transport and exchange, by using composite scores for quantification of lung injury (lung injury score [LIS]) and mechanical ventilator settings (PIF score). Pulmonary function was related to the Hunt and Hess (H & H) grade assigned to the patient at hospital admission (p < 0.001). The pattern and time course of lung injury differed significantly between patients with H & H Grade I or II, Grade III, and Grade IV or V. Hunt and Hess grade, Fisher computerized tomography grade, intracranial pressure, cerebral perfusion pressure, LIS, ratio of PaO2 to the fraction of inspired oxygen (FiO2), and the ratio of the alveolar-minus-arterial oxygen tension difference (AaDO2) to FiO2 were related to neurological outcome (p < 0.001). The LIS on the day of maximum lung injury remained an independent predictor of outcome (p = 0.01) in a stepwise logistic regression analysis. The probability of poor neurological outcome significantly increased with both decreasing cerebral perfusion pressure and increasing severity of lung injury.

CONCLUSIONS

The overall mortality rate was 22.2% (46 of 207 patients). Subarachnoid hemorrhage and its neurological sequelae accounted for the principal mortality in this series. Medical (nonneurological and nontreatment-related) complications accounted for 37% of all deaths. Systemic inflammatory response syndrome with associated multiple organ dysfunction syndrome was the leading cause of death from medical complications. The authors conclude that respiratory failure is related to neurological outcome, although it is not commonly the primary cause of death from medical complications.

Therapeutic effects of rhubarb on gastrointestinal failure

AIM: To investigate the effects of rhubarb on gastrointestinal failure and the underlying pharmaceutical mechanism.

METHODS: Ninety-seven patients in intensive care unit were divided into a treatment group (76 critically ill patients complicated with gastrointestinal failure) and a control group (21 recovered patients). The effects of rhubarb on stress ulcer and toxic paralytic ileus in the patients were observed. The rectal and gastric intramural pH values, cardiac index, oxygen delivery, and oxygen consumption were measured.

RESULTS: Treatment with rhubarb achieved a significant curative effect in 30 of the 36 cases of stress ulcer complicated with gastrointestinal hemorrhage. Ha-2-receptor blocking agent had a poor effect on them (P < 0.05). Among the 49 cases of toxic paralytic ileus treated with rhubarb, peristalsis was recovered in 41, and gastrointestinal nutrition could be tolerated in 24, while other medicine had no effect on them. According to gastric and rectal intramural pH, rhubarb could improve gut mucosa perfusion. Among the 23 cases of multiple organ dysfunction syndrome who received treatment with rhubarb, 9 survived.

CONCLUSION: This study suggests that rhubarb has a good curative effect on gastrointestinal failure.

Endotoxin inhibitor prevents sepsis-induced alterations in intestinal ion transport

BACKGROUND

The intestine is a target of septic insult. The aims of this study were to characterize sepsis-induced alterations in intestinal ion transport and to determine the role endotoxin plays in mediating these changes.

METHODS

Rats underwent cecal manipulation alone (control), cecal ligation and puncture (CLP), or CLP plus intraperitoneal injection of 0.2 mg of a recently synthesized endotoxin inhibitor. At 24 hours, distal ileum was harvested, and transport parameters were determined.

RESULTS

Cecal ligation and puncture produced a significant increase in short-circuit current (Isc) that was attributable to the induction of chloride secretion. There were no alterations in transepithelial resistance or fluxes of mannitol and sodium. The sepsis-induced increase in Isc was prevented by administration of the endotoxin inhibitor.

CONCLUSIONS

In this model of sepsis, the primary alteration in ileal ion transport is an induction of electrogenic chloride secretion. Endotoxin inhibition may represent a strategy for prophylaxis against the intestinal effects of sepsis.

Glutamine supplementation does not prevent small bowel mucosal atrophy after total parenteral nutrition in the rat

Glutamine supplementation to non-lipid parenteral nutrition has been demonstrated to attenuate villus atrophy and increase mucosal DNA content in the rat. This study was performed in order to determine the effects of glutamine supplementation to a balanced TPN mixture (including lipids) on epithelial cell kinetics using autoradiography. Male Sprague-Dawley rats were used. Group 1 (control) received food and an intravenous saline infusion. Group 2 received an intravenous TPN mixture including lipids but without glutamine. The same TPN mixture, glutamine replacing an isonitrogenous amount of non-essential amino acids, was given to Group 3. Animals were fed for 7 days, whereafter blood and intestinal samples were taken 1 h after injection of tritiated thymidine. Microscopy of specimens from proximal jejunum revealed a significant reduction in the number of cells in crypts and villi in both TPN groups (2 and 3) compared to orally fed animals (p < 0.001). Epithelial cell numbers were not significantly different in Group 2 and 3. Similarly, the labelling index (number of labelled cells/number of crypt cells) was not affected by glutamine administration. In plasma, glucagon concentrations in Group 2 (TPN without glutamine) seemed to decrease compared to Group 1 and 3 (p = 0.06). In this study, glutamine supplementation did not affect apithelial atrophy or cell proliferation. It is concluded, that the effects of glutamine on mucosal atrophy and renewal in jejunum may depend on the composition of the TPN mixture supplied during parenteral feeding.

Pneumonia: cause or symptom of postinjury multiple organ failure?

Recent studies have shown that selective gut decontamination can reduce the incidence of pneumonia, but this does not decrease multiple organ failure (MOF) or mortality. These findings have prompted the hypothesis that pneumonia is an inconsequential symptom of MOF. To test this, we prospectively evaluated 123 high-risk trauma patients (mean Injury Severity Score = 36.2 +/- 1.5). Organ dysfunction, scored daily according to a 12-point scale, ultimately developed in 28 (23%) patients. Major infections were diagnosed, based on strict criteria, in 59 patients (48%), and pneumonia developed in 52 patients (43%). Pneumonia was significantly associated with MOF (82% of patients with MOF versus 30% of patients without MOF, p < 0.0001). In 14 (50%) of the patients with MOF, pneumonia preceded a significant rise (greater than or equal to 3) in serial MOF scoring. Of note, 10 (71%) of these patients died. Among the remaining 14 patients with MOF, 10 developed pneumonia, but this was associated with a minimal increase (less than or equal to 2) in MOF scoring (3 patients died). These data, by temporal association with MOF scoring, implicate pneumonia in precipitating or significantly worsening organ failure in 50% of the patients who developed MOF.