Ethacrynic acid decreases expression of proinflammatory intestinal wall cytokines and ameliorates gastrointestinal stasis in murine postoperative ileus.

OBJECTIVES: Several compounds characterized by an olefin linkage conjugated to a carbonyl group have anti-inflammatory properties. The diuretic ethacrynic acid (EA) is a compound of this type. Herein, we tested the hypothesis that ethacrynic acid can modulate the development of ileus after bowel manipulation. METHODS: Groups (n=9) of male C57Bl/6 mice underwent surgical manipulation of the small intestine using a pair of cotton-tipped applicators (MAN). Control animals (CONT) did not undergo any surgical intervention or receive treatment. MAN mice were pre- and post-treated with four intraperitoneal doses of phosphate buffered saline (PBS), EA1 (1mg/kg per dose), or EA10 (10mg/kg per dose). Gastrointestinal transit of non-absorbable FITC-labeled dextran was assessed by gavaging the mice with the tracer 24h after operation and assessing FD70 concentration 120 min later in the bowel contents from the stomach, 10 equally long segments of small intestine, cecum, and two equally long segments of colon. The geometric center for the tracer was calculated for each animal. Expression of interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) transcripts in the ileal muscularis propria was assessed using semiquantitative reverse transcriptase-polymerase chain reaction. RESULTS: In control animals, the mean (±SE) geometric center for the transit marker was 9.89±0.47, whereas it was 4.59±0.59 for PBS-treated animals (p<0.05 vs CONT). The geometric center for pre- post treatment with low (1mg/kg) and high (10mg/kg) doses of ethacrynic acid were 7.23±0.97 and 5.15±0.57, respectively. Compared to PBS, treatment with ethacrynic acid (1mg/kg) significantly decreased manipulation-induced IL-6 and iNOS mRNA expression in the wall of the small bowel. CONCLUSIONS: Pre- and post-treatment with ethacrynic acid ameliorates ileus and modulates inflammation in the gut wall induced by bowel manipulation.

Ethacrynic acid decreases expression of proinflammatory intestinal wall cytokines and ameliorates gastrointestinal stasis in murine postoperative ileus

OBJECTIVES: Several compounds characterized by an olefin linkage conjugated to a carbonyl group have anti-inflammatory properties. The diuretic ethacrynic acid (EA) is a compound of this type. Herein, we tested the hypothesis that ethacrynic acid can modulate the development of ileus after bowel manipulation. METHODS: Groups (n=9) of male C57Bl/6 mice underwent surgical manipulation of the small intestine using a pair of cotton-tipped applicators (MAN). Control animals (CONT) did not undergo any surgical intervention or receive treatment. MAN mice were pre- and post-treated with four intraperitoneal doses of phosphate buffered saline (PBS), EA1 (1mg/kg per dose), or EA10 (10mg/kg per dose). Gastrointestinal transit of non-absorbable FITC-labeled dextran was assessed by gavaging the mice with the tracer 24h after operation and assessing FD70 concentration 120 min later in the bowel contents from the stomach, 10 equally long segments of small intestine, cecum, and two equally long segments of colon. The geometric center for the tracer was calculated for each animal. Expression of interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) transcripts in the ileal muscularis propria was assessed using semiquantitative reverse transcriptase-polymerase chain reaction. RESULTS: In control animals, the mean (±SE) geometric center for the transit marker was 9.89±0.47, whereas it was 4.59±0.59 for PBS-treated animals (p<0.05 vs CONT). The geometric center for pre- post treatment with low (1mg/kg) and high (10mg/kg) doses of ethacrynic acid were 7.23±0.97 and 5.15±0.57, respectively. Compared to PBS, treatment with ethacrynic acid (1mg/kg) significantly decreased manipulation-induced IL-6 and iNOS mRNA expression in the wall of the small bowel. CONCLUSIONS: Pre- and post-treatment with ethacrynic acid ameliorates ileus and modulates inflammation in the gut wall induced by bowel manipulation.

Angiotensin II for the Treatment of High-Output Shock 3 (ATHOS-3): protocol for a phase III, double-blind, randomised controlled trial.

OBJECTIVE: Catecholamine-resistant hypotension (CRH) is characterised by inadequate response to standard doses of vasopressors, and increased mortality. Our Angiotensin II for the Treatment of High-Output Shock 3 (ATHOS-3) trial compares the efficacy and safety of angiotensin II (ANGII) versus placebo in CRH. DESIGN, SETTING AND PARTICIPANTS: A phase III, multicentre, randomised, placebo-controlled trial of LJPC-501 (synthetic ANGII) for CRH in up to 120 intensive care units. We have set a target of 300 critically ill patients with CRH receiving standard-of-care (SOC) vasopressor therapy (ie, catecholamine dose > 0.2 µg/kg/min for 6-48 hours to maintain a mean arterial pressure [MAP] of 55-70 mmHg). Calculation of a norepinephrine-equivalent vasopressor dose is critical to determining patient eligibility, as ANGII will supplement ongoing vasopressor therapy. INTERVENTIONS: Stable patients will be randomised 1:1 to SOC vasopressor plus continuous intravenous infusion of ANGII or placebo for 48 hours, with an aim of achieving MAP of 75 mmHg for the first 3 hours. ANGII (initiated at 20 ng/ kg/min) will be titrated according to pre-specified guidelines until 48 hours, with patients followed until Day 7. Frequent vital sign and haemodynamic monitoring will support ANGII titration, safety monitoring and efficacy assessments. MAIN OUTCOME MEASURES: The primary efficacy endpoint is MAP ≥ 75 mmHg or an increase of ≥ 10 mmHg at treatment Hour 3. Secondary endpoints include change in total and cardiovascular Sequential Organ Failure Assessment scores over 48 hours, and safety data. CONCLUSION: Our study will investigate the utility of adding ANGII to current SOC vasopressor options to increase the efficacy and safety of CRH therapy.

Ethyl pyruvate modulates delayed paralysis following thoracic aortic ischemia reperfusion in mice.

OBJECTIVE: Delayed paralysis is an unpredictable problem for patients undergoing complex repair of the thoracic/thoracoabdominal aorta. These experiments were designed to determine whether ethyl pyruvate (EP), a potent anti-inflammatory and antioxidant agent, might ameliorate delayed paralysis following thoracic aortic ischemia reperfusion (TAR). METHODS: C57BL6 mice were subjected to 5 minutes of thoracic aortic ischemia followed by reperfusion for up to 48 hours. Mice received either 300 mg/kg EP or lactated ringers (LR) at 30 minutes before ischemia and 3 hours after reperfusion. Neurologic function was assessed using an established rodent scale. Spinal cord tissue was analyzed for markers of inflammation (keratinocyte chemoattractant [KC], interleukin-6 [IL-6]), microglial activation (ionized calcium-binding adapter molecule-1 [Iba-1]), and apoptosis (Bcl-2, Bax, and terminal deoxynucleotidyl transferase dUTP nick end labeling [TUNEL] staining) at 24 and 48 hours after TAR. Nissl body stained motor neurons were counted in the anterior horns sections from L1-L5 segments. RESULTS: Ninety-three percent of the LR mice developed dense delayed paralysis between 40 and 48 hours after TAR, whereas only 39% of EP mice developed delayed paralysis (P < .01). Bcl-2 expression was higher (P < .05) and Iba-1 expression was lower (P < .05) in the EP group only at 24 hours reperfusion. At 48 hours, the number of motor neurons was higher (P < .01) and the number and TUNEL-positive cells was lower (P < .001) in the EP-treated mice. EP decreased the expression of KC (P < .01) and IL-6 (P < .001) at 48 hours after TAR. CONCLUSIONS: The protection provided by EP against delayed paralysis correlated with preservation of motor neurons, higher expression of antiapoptotic molecules, decreased microglial cell activation, and decreased spinal cord inflammation. EP may be a treatment for humans at risk for delayed paralysis.

THE EPITHELIUM AS A TARGET IN SEPSIS.

Organ dysfunction induced by sepsis has been consistently associated with worse outcome and death. Regardless of the organ compromised, epithelial dysfunction is present throughout the body, affecting those organs that contain epithelia like the skin, lungs, liver, gut, and kidneys. Despite their obvious differences, sepsis seems to alter common features of all epithelia, such as barrier function and vectorial ion transport. Such alterations in the lung, the gut, and the kidney have direct implications that may explain the profound organ functional impairments in the absence of overt cell death. Epithelial injury in this context is not only an explanatory real pathophysiologic event, but also represents a source of biomarkers that have been explored to identify organ compromise earlier, predict outcome, and even to test novel therapeutic interventions such as blood purification. However, this remains largely experimental, and despite promising results, work is still required to better understand the response of the epithelial cells to sepsis, to define their role in adaptation to insults, to comprehend the interorgan cross-talk that occurs in these circumstances, and to exploit these aspects in pursuit of targeted therapies like blood purification, which may improve outcome for these patients in the future.

Successful use of extracorporeal membrane oxygenation in an adult patient with toxic shock-induced heart failure.

Cardiomyopathy secondary to toxic shock syndrome (TSS) is an uncommon but potentially life-threatening problem. We report the case of a 51-year-old male who presented with profound cardiogenic shock and multiorgan failure that could not be managed by conventional therapy with intravenous fluids, vasopressors and inotropes. Venoarterial extracorporeal membrane oxygenation (VA ECMO) was instituted as a bridge to recovery. After administration of antibiotics and intravenous immunoglobulin, the patient's condition improved and he was successfully weaned off ECMO after 6 days. The patient recovered from multiorgan failure, and left ventricular ejection fraction improved from <10% pre-ECMO to 65% 8 months after discharge. This case supports the view that VA ECMO can be used successfully to support vital organ perfusion in patients with profound but reversible cardiomyopathy attributed to TSS.

Strategies to improve drug development for sepsis.

Sepsis, a common and potentially fatal systemic illness, is triggered by microbial infection and often leads to impaired function of the lungs, kidneys or other vital organs. Since the early 1980s, a large number of therapeutic agents for the treatment of sepsis have been evaluated in randomized controlled clinical trials. With few exceptions, the results from these trials have been disappointing, and no specific therapeutic agent is currently approved for the treatment of sepsis. To improve upon this dismal record, investigators will need to identify more suitable therapeutic targets, improve their approaches for selecting candidate compounds for clinical development and adopt better designs for clinical trials.

HMGB1 as a drug target in staphylococcal pneumonia.

High mobility group box (HMGB)1 is a small DNA-binding protein. In the nucleus, HMGB1 plays a role in gene expression and DNA replication. When it is released or secreted into the extracellular milieu, HMGB1 functions as a pro-inflammatory cytokine-like mediator. Recently reported data support the view that treatment with a neutralizing anti-HMGB1 antibody ameliorated pulmonary damage in a murine model of pneumonia caused by a pathogenic strain of Staphylococcus aureus. These findings suggest that HMGB1 may be an important drug target as scientists, clinical investigators and pharmaceutical companies seek to develop better agents for the treatment of staphylococcal pneumonia. Unfortunately, however, encouraging results from murine models of human disease often fail to translate into positive findings in clinical trials. Thus, before moving from pre-clinical into clinical studies, it may be prudent to validate and extend the recent experimental findings by carrying out additional studies, using a large animal model of pneumonia.

p-Hydroxyphenylpyruvate, an intermediate of the Phe/Tyr catabolism, improves mitochondrial oxidative metabolism under stressing conditions and prolongs survival in rats subjected to profound hemorrhagic shock.

The aim of this study was to test the effect of a small volume administration of p-hydroxyphenylpyruvate (pHPP) in a rat model of profound hemorrhagic shock and to assess a possible metabolic mechanism of action of the compound. The results obtained show that hemorrhaged rats treated with 2-4% of the estimated blood volume of pHPP survived significantly longer (p<0.001) than rats treated with vehicle. In vitro analysis on cultured EA.hy 926 cells demonstrated that pHPP improved cell growth rate and promoted cell survival under stressing conditions. Moreover, pHPP stimulated mitochondria-related respiration under ATP-synthesizing conditions and exhibited antioxidant activity toward mitochondria-generated reactive oxygen species. The compound effects reported in the in vitro and in vivo analyses were obtained in the same millimolar concentration range. These data disclose pHPP as an efficient energetic substrates-supplier to the mitochondrial respiratory chain as well as an antioxidant supporting the view that the compound warrants further evaluation as a therapeutic agent.

Animal models of sepsis.

Sepsis remains a common, serious, and heterogeneous clinical entity that is difficult to define adequately. Despite its importance as a public health problem, efforts to develop and gain regulatory approval for a specific therapeutic agent for the adjuvant treatment of sepsis have been remarkably unsuccessful. One step in the critical pathway for the development of a new agent for adjuvant treatment of sepsis is evaluation in an appropriate animal model of the human condition. Unfortunately, the animal models that have been used for this purpose have often yielded misleading findings. It is likely that there are multiple reasons for the discrepancies between the results obtained in tests of pharmacological agents in animal models of sepsis and the outcomes of human clinical trials. One of important reason may be that the changes in gene expression, which are triggered by trauma or infection, are different in mice, a commonly used species for preclinical testing, and humans. Additionally, many species, including mice and baboons, are remarkably resistant to the toxic effects of bacterial lipopolysaccharide, whereas humans are exquisitely sensitive. New approaches toward the use of animals for sepsis research are being investigated. But, at present, results from preclinical studies of new therapeutic agents for sepsis must be viewed with a degree of skepticism.

Analyzing the value of monitoring duodenal mucosal perfusion using photoplethysmography.

Photoplethysmography (PPG) is a technique that permits noninvasive measurement of changes in the volume of tissues. A novel device uses PPG to assess changes in duodenal mucosal perfusion. When tested in septic piglets, data obtained using this device correlate with the blood lactate concentration and duodenal serosal microvascular blood flow as measured with a laser Doppler flowmeter. This new PPG-based approach for continuously monitoring gut mucosal perfusion warrants further development, leading to prospective clinical trials in patients.

Identification of a novel pathway of transforming growth factor-ß1 regulation by extracellular NAD+ in mouse macrophages: in vitro and in silico studies.

Extracellular ß-nicotinamide adenine dinucleotide (NAD(+)) is anti-inflammatory. We hypothesized that NAD(+) would modulate the anti-inflammatory cytokine Transforming Growth Factor (TGF)-ß1. Indeed, NAD(+) led to increases in both active and latent cell-associated TGF-ß1 in RAW 264.7 mouse macrophages as well as in primary peritoneal macrophages isolated from both C3H/HeJ (TLR4-mutant) and C3H/HeOuJ (wild-type controls for C3H/HeJ) mice. NAD(+) acts partially via cyclic ADP-ribose (cADPR) and subsequent release of Ca(2+). Treatment of macrophages with the cADPR analog 3-deaza-cADPR or Ca(2+) ionophores recapitulated the effects of NAD(+) on TGF-ß1, whereas the cADPR antagonist 8-Br-cADPR, Ca(2+) chelation, and antagonism of L-type Ca(2+) channels suppressed these effects. The time and dose effects of NAD(+) on TGF-ß1 were complex and could be modeled both statistically and mathematically. Model-predicted levels of TGF-ß1 protein and mRNA were largely confirmed experimentally but also suggested the presence of other mechanisms of regulation of TGF-ß1 by NAD(+). Thus, in vitro and in silico evidence points to NAD(+) as a novel modulator of TGF-ß1.

Pathophysiology of perioperative anaemia.

Perioperative anaemia is a common clinical entity. It is usually due to combination of various mechanisms, including: pre-existing anaemia prior to surgery; anaemia due to impaired erythropoiesis, including alterations of metabolism of iron and erythropoietin (EPO); anaemia due to increased destruction of red blood cells (RBCs); and anaemia due to iatrogenic causes. Postoperatively, anaemia resembles anaemia of chronic disease and is probably related to the effects of inflammatory mediators released during and after surgery on the production and survival of RBCs. Pro-inflammatory cytokines, such as tumour necrosis factor, impair erythropoietin-dependent signalling and iron homeostasis. Iatrogenic causes, notably excessive phlebotomies, remain a major cause of perioperative anaemia. With increasing emphasis on restrictive blood transfusion strategies, understanding these mechanisms is important for the clinician.