Administration of glutamine after hemorrhagic shock restores cellular energy, reduces cell apoptosis and damage, and increases survival

Anti-interferon-α receptor 1 antibodies attenuate inflammation and organ injury following hemorrhagic shock

BACKGROUND

Hemorrhagic shock (HS) is a life-threatening condition resulting from rapid and significant loss of intravascular volume, leading to hemodynamic instability and death. Inflammation contributes to the multiple organ injury in HS. Type I interferons (IFNs), such as IFN-α and IFN-β, are a family of cytokines that regulate the inflammatory response through binding to IFN-α receptor (IFNAR) which consists of IFNAR1 and IFNAR2 chains. We hypothesized that type I IFNs provoke inflammation and worsen organ injury in HS.

METHODS

Male C57BL/6 mice (20-25 g) underwent hemorrhage by controlled bleeding via the femoral artery to maintain a mean arterial pressure of 27 ± 2.5 mm Hg for 90 minutes, followed by resuscitation for 30 minutes with two times shed blood volume of Ringer's lactate solution containing 1 mg/kg body weight of anti-IFNAR1 antibody (Ab) or control isotype-matched IgG (IgG). Blood and tissue samples were collected at 20 hours after the resuscitation for various analyses.

RESULTS

The expression of IFN-α and IFN-β mRNAs was significantly elevated in lungs and liver of the mice after HS. The IFNAR1-Ab treatment significantly decreased serum levels of organ injury markers lactate dehydrogenase and aspartate aminotransferase, as well as improved the integrity of lung and liver morphology, compared to the IgG control. The protein levels of proinflammatory cytokines TNF-α and IL-6, and mRNA expression of proinflammatory chemokines monocyte chemoattractant protein (MCP)-1, MCP-2, macrophage inflammatory protein 2 (MIP-2), and keratinocyte cytokine (KC) in the lungs of the HS mice were significantly decreased after treated with IFNAR1-Ab. Moreover, the myeloperoxidase activity and number of apoptotic cells in the lungs of HS mice treated with IFNAR1-Ab were decreased in comparison to the IgG control.

CONCLUSION

Administration of IFNAR1-Ab reduces inflammation and tissue injury. Thus, type I IFN signaling may be a potential therapeutic target for mitigating organ dysfunction in patients suffering from HS.

STUDY TYPE

Translational animal model.

Plasma First Resuscitation Reduces Lactate Acidosis, Enhances Redox Homeostasis, Amino Acid and Purine Catabolism in a Rat Model of Profound Hemorrhagic Shock

The use of aggressive crystalloid resuscitation to treat hypoxemia, hypovolemia, and nutrient deprivation promoted by massive blood loss may lead to the development of the blood vicious cycle of acidosis, hypothermia, and coagulopathy and, utterly, death. Metabolic acidosis is one of the many metabolic derangements triggered by severe trauma/hemorrhagic shock, also including enhanced proteolysis, lipid mobilization, as well as traumatic diabetes. Appreciation of the metabolic benefit of plasma first resuscitation is an important concept. Plasma resuscitation has been shown to correct hyperfibrinolysis secondary to severe hemorrhage better than normal saline. Here, we hypothesize that plasma first resuscitation corrects metabolic derangements promoted by severe hemorrhage better than resuscitation with normal saline. Ultra-high-performance liquid chromatography-mass spectrometry-based metabolomics analyses were performed to screen plasma metabolic profiles upon shock and resuscitation with either platelet-free plasma or normal saline in a rat model of severe hemorrhage. Of the 251 metabolites that were monitored, 101 were significantly different in plasma versus normal saline resuscitated rats. Plasma resuscitation corrected lactate acidosis by promoting glutamine/amino acid catabolism and purine salvage reactions. Plasma first resuscitation may benefit critically injured trauma patients by relieving the lactate burden and promoting other non-clinically measured metabolic changes. In the light of our results, we propose that plasma resuscitation may promote fueling of mitochondrial metabolism, through the enhancement of glutaminolysis/amino acid catabolism and purine salvage reactions. The treatment of trauma patients in hemorrhagic shock with plasma first resuscitation is likely not only to improve coagulation, but also to promote substrate-specific metabolic corrections.

Protective Effects of Curcumin on Intestinal Damage in Cholestatic Rats

BACKGROUND

The aim of this study was to evaluate the possible protective effects of curcumin on oxidative stress, cell proliferation, and apoptosis in the rat intestinal mucosa after bile duct ligation (BDL).

METHODS

A total of 18 male Sprague Dawley rats were divided into three groups: sham control, BDL and BDL+curcumin; each group contain six animals. The rats in the curcumin-treated group were given curcumin (100 mg/kg) once a day orally for 14 days, starting 3 days prior to BDL operation. Following 14 days of treatment, all the animals were decapitated and intestinal tissues samples obtained for biochemical and histopathological investigation.

RESULTS

Curcumin treatment was found to significantly lower elevated tissue malondialdehyde levels and myeloperoxidase activity, and to raise reduced glutathione levels in intestinal tissues samples. BDL caused severe histopathological injury, including shortening of the villi, loss of villous epithelium, multiple erosions, inflammatory cell infiltration, necrosis, and hemorrhage into the intestinal wall. Curcumin treatment significantly attenuated the severity of intestinal injury, with inhibition of BDL-induced apoptosis and cell proliferation.

CONCLUSION

Curcumin treatment has a protective effect against intestinal damage induced by BDL. The ability of curcumin treatment is to inhibit BDL-induced oxidative stress, apoptosis, and cell proliferation.

Inhibition of fatty acid synthase with C75 decreases organ injury after hemorrhagic shock

BACKGROUND

Hemorrhagic shock is the primary cause of morbidity and mortality in the intensive care units in patients under the age of 35. Several organs, including the lungs, are seriously affected by hemorrhagic shock and inadequate resuscitation. Excess free fatty acids have shown to trigger inflammation in various disease conditions. C75 is a small compound that inhibits fatty acid synthase, a key enzyme in the control of fatty acid metabolism that also stimulates fatty acid oxidation. We hypothesized that C75 treatment would be protective against hemorrhagic shock.

METHODS

Adult male Sprague-Dawley rats were cannulated with a femoral artery catheter and subjected to controlled bleeding. Blood was shed to maintain a mean arterial pressure of 30 mm Hg for 90 minutes, then resuscitated over 30 minutes with a crystalloid volume equal to twice the volume of shed blood. Fifteen minutes into the 30-minute resuscitation, the rats received either intravenous infusion of C75 (1 mg/kg body weight) or vehicle (20% dimethyl sulfoxide). Blood and tissue samples were collected 6 hours after resuscitation (ie, 7.5 hours after hemorrhage) for analysis.

RESULTS

After hemorrhage and resuscitation, C75 treatment decreased the increase in serum free fatty acids by 48%, restored adenosine triphosphate levels, and stimulated carnitine palmitoyl transferase-1 activity. Administration of C75 decreased serum levels of markers of injury (aspartate aminotransferase, lactate, and lactate dehydrogenase) by 38%, 32%, and 78%, respectively. Serum creatinine and blood urea nitrogen were also decreased significantly by 38% and 40%, respectively. These changes correlated with decreases in neutrophil infiltration in the lung, evidenced by decreases in Gr-1-stained cells and myeloperoxidase activity and improved lung histology. Finally, administration of C75 decreased pulmonary mRNA levels of cyclooxygenase-2 and interleukin-6 by 87% and 65%, respectively.

CONCLUSION

Administration of C75 after hemorrhage and resuscitation decreased the increase in serum free fatty acids, decreased markers of tissue injury, downregulated the expression of inflammatory mediators, and decreased neutrophil infiltration and lung injury. Thus, the dual action of inhibiting fatty acid synthesis and stimulating fatty acid oxidation by C75 could be developed as a promising adjuvant therapy strategy to protect against hemorrhagic shock.

1H-NMR metabolomic biomarkers of poor outcome after hemorrhagic shock are absent in hibernators

Background

Hemorrhagic shock (HS) following trauma is a leading cause of death among persons under the age of 40. During HS the body undergoes systemic warm ischemia followed by reperfusion during medical intervention. Ischemia/reperfusion (I/R) results in a disruption of cellular metabolic processes that ultimately lead to tissue and organ dysfunction or failure. Resistance to I/R injury is a characteristic of hibernating mammals. The present study sought to identify circulating metabolites in the rat as biomarkers for metabolic alterations associated with poor outcome after HS. Arctic ground squirrels (AGS), a hibernating species that resists I/R injury independent of decreased body temperature (warm I/R), was used as a negative control.

Methodology/principal findings

Male Sprague-Dawley rats and AGS were subject to HS by withdrawing blood to a mean arterial pressure (MAP) of 35 mmHg and maintaining the low MAP for 20 min before reperfusing with Ringers. The animals’ temperature was maintained at 37±0.5°C for the duration of the experiment. Plasma samples were taken immediately before hemorrhage and three hours after reperfusion. Hydrophilic and lipid metabolites from plasma were then analyzed via ¹H–NMR from unprocessed plasma and lipid extracts, respectively. Rats, susceptible to I/R injury, had a qualitative shift in their hydrophilic metabolic fingerprint including differential activation of glucose and anaerobic metabolism and had alterations in several metabolites during I/R indicative of metabolic adjustments and organ damage. In contrast, I/R injury resistant AGS, regardless of season or body temperature, maintained a stable metabolic homeostasis revealed by a qualitative ¹H–NMR metabolic profile with few changes in quantified metabolites during HS-induced global I/R.

Conclusions/significance

An increase in circulating metabolites indicative of anaerobic metabolism and activation of glycolytic pathways is associated with poor prognosis after HS in rats. These same biomarkers are absent in AGS after HS with warm I/R.

The effects of hyperbaric oxygen application against cholestatic oxidative stress and hepatic damage after bile duct ligation in rats

BACKGROUND

The aim of this study was to evaluate the preventive and therapeutic potential of hyperbaric oxygen therapy (HBO) on the liver tissue against bile duct ligation (BDL)-induced oxidative damage and fibrosis in rats.

MATERIALS AND METHODS

We divided 32 adult male Sprague Dawley rats into four groups: sham, sham plus HBO, BDL, and BDL plus HBO; each group contained eight animals. We placed the sham plus HBO and BDL plus HBO groups in an experimental hyperbaric chamber in which we administered pure oxygen at 2.5 atmospheres absolute 100% oxygen for 90 min on 14 consecutive days.

RESULTS

The application of BDL clearly increased the tissue malondialdehyde level, myeloperoxidase activity, and hydroxyproline content and decreased the antioxidant enzymes (superoxide dismutase and catalase activities) and glutathione level. Hyperbaric oxygen therapy treatment significantly decreased the elevated tissue malondialdehyde level, myeloperoxidase activity, and hydroxyproline content and increased the reduced superoxide dismutase and catalase activities and glutathione level in the tissues. The changes demonstrating the bile duct proliferation and fibrosis in expanded portal tracts include the extension of proliferated bile ducts into lobules, mononuclear cells, and neutrophil infiltration into the widened portal areas were observed in BDL group. Treatment of BDL with HBO attenuated alterations in liver histology. Alpha smooth muscle actin, cytokeratin-positive ductular proliferation, and the activity of terminal deoxynucleotidyl transferase 2'-deoxyuridine, 5'-triphosphate nick end labeling in the BDL decreased with HBO treatment.

CONCLUSIONS

The data indicate that HBO attenuates BDL-induced oxidative injury, hepatocytes damage, bile duct proliferation, and fibrosis. The hepatoprotective effect of HBO is associated with antioxidative potential.

Resuscitation after hemorrhagic shock: the effect on the liver--a review of experimental data

The liver is currently considered to be one of the first organs to be subjected to the hypoxic insult inflicted by hemorrhagic shock. The oxidative injury caused by resuscitation also targets the liver and can lead to malfunction and the eventual failure of this organ. Each of the various fluids, vasoactive drugs, and pharmacologic substances used for resuscitation has its own distinct effect(s) on the liver, and the anesthetic agents used during surgical resuscitation also have an impact on hepatocytes. The aim of our study was to identify the specific effect of these substances on the liver. To this end, we conducted a literature search of MEDLINE for all types of articles published in English, with a focus on articles published in the last 12 years. Our search terms were "hemorrhagic shock," "liver," "resuscitation," "vasopressors," and "anesthesia." Experimental studies form the majority of articles found in bibliographic databases. The effect of a specific resuscitation agent on the liver is assessed mainly by measuring apoptotic pathway regulators and inflammation-induced indicators. Apart from a wide range of pharmacological substances, modifications of Ringer's Lactate, colloids, and pyruvate provide protection to the liver after hemorrhage and resuscitation. In this setting, it is of paramount importance that the treating physician recognize those agents that may attenuate liver injury and avoid using those which inflict additional damage.

Ringer's malate solution protects against the multiple organ injury and dysfunction caused by hemorrhagic shock in rats

Malic acid, in the form of its anion malate, is a key intermediate in the major biochemical energy-producing cycle known as the citric acid or Krebs cycle. In this study, the authors investigated the protective effect of a novel crystalloid solution of Ringer's malate following fluid resuscitation of hemorrhagic shock using a rat model. Under general anesthesia, Sprague-Dawley male rats were subjected to 60 min of hemorrhagic shock (40 mmHg for 60 min) followed by crystalloid resuscitation. Groups were as follows: (1) sham shock, (2) normal saline, (3) Ringer's lactate, and (4) Ringer's malate. The experiment was terminated at 4 h after resuscitation. Mean arterial blood pressure (MAP) and blood biophysical parameters were monitored during the experiment. The alanine aminotransferase, aspartate aminotransferase, urea, creatinine, superoxide dismutase, and malondialdehyde levels in plasma were detected. The intestine, liver, lung, and renal histopathology were measured. It was found that Ringer's malate could increase MAP immediately and maintain MAP for a long time. Ringer's malate could reduce the level of alanine aminotransferase, aspartate aminotransferase, urea, and creatinine. At the same time, the activity of superoxide dismutase was increased, and the level of malondialdehyde was decreased. Histopathology indicated that Ringer's malate can protect against the multiple organ injury caused by hemorrhagic shock in rats. Ringer's malate prevented circulatory failure and alleviated multiple organ dysfunction syndrome in animals with hemorrhagic shock. The study suggests that Ringer's malate solution could be a potential novel therapeutic agent for fluid resuscitation.

Effects of albumin administration in serum liver enzymes of rats in the presence of extrahepatic biliary obstruction

PURPOSE

To study the influence of albumin on changes of liver function in the extrahepatic biliary obstruction through an experimental model in rats.

METHODS

Sixty rats were divided into four groups: Group C (Control): 6 animals. Group M (Fictitious Operation): 18 rats underwent laparotomy and handling of the bile ducts; Groups O (extrahepatic biliary obstruction) and A (Treated with 2% albumin): 18 animals in each group underwent ligation of the ductus liver; The animals in groups M, O and A were divided into three subgroups of 6 animals each to be killed in the 7, 14 and 21 days postoperative (POD). Blood was drawn for determination of total bilirubin (TB), indirect bilirubin (IB), direct bilirubin (DB), alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT).

RESULTS

On POD 7, BI levels were 4.5 mg / dl in group O and 2.1 mg / dl in group A (p = 0.025). On the 14th POD, the levels of PA were 1185.2 U / l in the group and O 458.3 U / l in group A (p = 0.004). ALT levels were 101.7 U / l in the group O and 75.7 U / l in group A (= 0.037). On POD 21, the levels of ALP were 1069.5 U / l in the group O and 468.3 U / l in group A (p = 0, 004).

CONCLUSION

The administration of albumin reduced the serum levels of bilirubin in the 7th day of supplementation.

Acute ethanol gavage attenuates hemorrhage/resuscitation-induced hepatic oxidative stress in rats

Acute ethanol intoxication increases the production of reactive oxygen species (ROS). Hemorrhagic shock with subsequent resuscitation (H/R) also induces ROS resulting in cellular and hepatic damage in vivo. We examined the role of acute ethanol intoxication upon oxidative stress and subsequent hepatic cell death after H/R. 14 h before H/R, rats were gavaged with single dose of ethanol or saline (5 g/kg, EtOH and ctrl; H/R_EtOH or H/R_ctrl, resp.). Then, rats were hemorrhaged to a mean arterial blood pressure of 30 ± 2 mmHg for 60 min and resuscitated. Two control groups underwent surgical procedures without H/R (sham_ctrl and sham_EtOH, resp.). Liver tissues were harvested at 2, 24, and 72 h after resuscitation. EtOH-gavage induced histological picture of acute fatty liver. Hepatic oxidative (4-hydroxynonenal, 4-HNE) and nitrosative (3-nitrotyrosine, 3-NT) stress were significantly reduced in EtOH-gavaged rats compared to controls after H/R. Proapoptotic caspase-8 and Bax expressions were markedly diminished in EtOH-gavaged animals compared with controls 2 h after resuscitation. EtOH-gavage increased antiapoptotic Bcl-2 gene expression compared with controls 2 h after resuscitation. iNOS protein expression increased following H/R but was attenuated in EtOH-gavaged animals after H/R. Taken together, the data suggest that acute EtOH-gavage may attenuate H/R-induced oxidative stress thereby reducing cellular injury in rat liver.

Plant polyphenols attenuate hepatic injury after hemorrhage/resuscitation by inhibition of apoptosis, oxidative stress, and inflammation via NF-kappaB in rats

PURPOSE

Oxidative stress and inflammation contribute to hepatic injury after hemorrhage/resuscitation (H/R). Natural plant polyphenols, i.e., green tea extract (GTE) possess high anti-oxidant and anti-inflammatory activities in various models of acute inflammation. However, possible protective effects and feasible mechanisms by which plant polyphenols modulate pro-inflammatory, apoptotic, and oxidant signaling after H/R in the liver remain unknown. Therefore, we investigated the effects of GTE and its impact on the activation of NF-kappaB in the pathogenesis of hepatic injury induced by H/R.

METHODS

Twenty-four female LEWIS rats (180-250 g) were fed a standard chow (ctrl) or a diet containing 0.1% polyphenolic extracts (GTE) from Camellia sinensis starting 5 days before H/R. Rats were hemorrhaged to a mean arterial pressure of 30 ± 2 mmHg for 60 min and resuscitated (H/R and GTE H/R groups). Control groups (sham, ctrl, and GTE) underwent surgical procedures without H/R. Two hours after resuscitation, tissues were harvested.

RESULTS

Plasma alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) increased 3.5-fold and fourfold, respectively, in vehicle-treated rats as compared to GTE-fed rats. Histopathological analysis revealed significantly decreased hepatic necrosis and apoptosis in GTE-fed rats after H/R. Real-time PCR showed that GTE diminished gene expression of pro-apoptotic caspase-8 and Bax, while anti-apoptotic Bcl-2 was increased after H/R. Hepatic oxidative (4-hydroxynonenal) and nitrosative (3-nitrotyrosine) stress as well as systemic IL-6 level and hepatic IL-6 mRNA were markedly reduced in GTE-fed rats compared with controls after H/R. Plant polyphenols also decreased the activation of both JNK and NFκB.

CONCLUSIONS

Taken together, GTE application blunts hepatic damage, apoptotic, oxidative, and pro-inflammatory changes after H/R. These results underline the important roles of JNK and NF-kappaB in inflammatory processes after H/R and the beneficial impact of plant polyphenols in preventing their activation.

Influence of glutamine on morphological and functional changes of liver in the presence of extrahepatic biliary obstruction in rats

PURPOSE: To study the influence of glutamine on functional and morphological changes of liver in the extrahepatic biliary obstruction through an experimental model in rats. METHODS: Seventy Wistar rats were divided into four groups: control (group C) fictitious operation, (group FO), submitted to laparotomy with handling of bile ducts, but without hepatic duct ligation, (group EBO) submitted to laparotomy and hepatic duct ligation, one of them submitted to supplementation with glutamine 2% (group G). The control group consisted of 6 animals. The animals from groups FO, EBO and G were divided into three groups consisting of 6 animals each, being sacrificed at 7, 14 and 21 days after operation, respectively. Blood samples were collected for biochemical analysis and a fragment of liver tissue was collected from the middle lobe for histological analysis. RESULTS: Both for biochemical analysis (BT, aspartate and alanine aminotransferase AST, ALT and alkaline phosphatase FAL) and for histopathological changes (fibrosis, portal inflammation, parenchymal inflammation, hepatocytic changes and duct proliferation), no statistical difference between groups submitted to extrahepatic biliary obstruction (EBO) with and without treatment with glutamine (G) was observed. CONCLUSION: Glutamine supplementation did not alter the prognosis of liver enzymes and histopathological changes in animals submitted to extrahepatic biliary obstruction.

Inhibition of c-Jun N-terminal kinase after hemorrhage but before resuscitation mitigates hepatic damage and inflammatory response in male rats

Inhibition of c-Jun N-terminal kinase (JNK) by a cell-penetrating, protease-resistant JNK peptide (D-JNKI-1) before hemorrhage and resuscitation (H/R) ameliorated the H/R-induced hepatic injury and blunted the proinflammatory changes. Here we tested the hypothesis if JNK inhibition at a later time point-after hemorrhagic shock but before the onset of resuscitation-in a rat model of H/R also confers protection. Twenty-four male Sprague-Dawley rats (250 - 350 g) were randomly divided into 4 groups: 2 groups of shock animals were hemorrhaged to a MAP of 32 to 37 mmHg for 60 min and randomly received either D-JNKI-1 (11 mg/kg i.p.) or sterile saline as vehicle immediately before the onset of resuscitation. Two groups of sham-operated animals underwent surgical procedures without H/R and were either D-JNKI-1 or vehicle treated. Rats were killed 2 h later. Serum activity of alanine aminotransferase and serum lactate dehydrogenase after H/R increased 3.5-fold in vehicle-treated rats as compared with D-JNKI-1-treated rats. Histopathological analysis revealed that hepatic necrosis and apoptosis (hematoxylin-eosin, TUNEL, and M30, respectively) were significantly inhibited in D-JNKI-1-treated rats after H/R. Hepatic oxidative (4-hydroxynonenal) and nitrosative (3-nitrotyrosine) stress as well as markers of inflammation (hepatic and serum IL-6 levels and hepatic infiltration with polymorphonuclear leukocytes) were also reduced in D-JNKI-1-treated rats. LPS-stimulated TNF-alpha release from whole blood from hemorrhaged and resuscitated animals was higher in vehicle-treated rats as compared with D-JNKI-1-treated rats. c-Jun N-terminal kinase inhibition after hemorrhage before resuscitation resulted in a reduced activation of c-Jun. Taken together, these results indicate that D-JNKI-1 application after hemorrhagic shock before resuscitation blunts hepatic damage and proinflammatory changes during resuscitation. Hence, JNK inhibition is even protective when initiated after blood loss before resuscitation. These experimental results indicate that the JNK pathway may be a possible treatment option for the harmful consequences of H/R.

Ketamine delays mortality in an experimental model of hemorrhagic shock and subsequent sepsis

BACKGROUND

In previous studies ketamine was reported to improve survival and decrease serum interleukin-6 (IL-6) concentration after sepsis alone and after burn injury followed by sepsis. The aim of this study was to determine whether ketamine alters survival and/or IL-6 after hemorrhagic shock alone or hemorrhagic shock followed by sepsis.

MATERIALS AND METHODS

Rats were subjected to hemorrhagic shock with or without subsequent Gram-negative bacterial sepsis and were either treated with ketamine 5 mg/kg or were not treated. Blood was sampled for IL-6 determination prior to hemorrhage, at the completion of resuscitation, and at 6 and 30 h later. Mortality was recorded for 7 days following hemorrhage or hemorrhage+sepsis.

RESULTS

After hemorrhage+sepsis the time to median mortality was significantly later in the ketamine-treated group (36 h) than in the control group (12 h). At 12h the survival rate of the ketamine-treated group (100%) was significantly higher than in the control group (55%). There were no significant differences between groups with respect to IL-6 or 7-day survival after either hemorrhage+sepsis or hemorrhage alone.

CONCLUSION

Ketamine improved 12h survival and delayed mortality after hemorrhage+sepsis without significantly altering IL-6, and did not alter survival or IL-6 after hemorrhage alone.

The patient with circulatory shock: to feed or not to feed?

Controversy continues to surround the appropriate form and timing of nutrition support for the patient with circulatory shock. Clinical studies have demonstrated improvements in outcome with the administration of enteral nutrition to critically ill patients; however, the provision of enteral nutrition to critically ill patients with ongoing shock remains controversial. This article reviews gut perfusion during normal states and during circulatory shock as well as alterations in perfusion when enteral feeding is provided. Pharmaconutrients studied during ischemia and reperfusion are discussed.

Glutamine: role in critical illness and ongoing clinical trials

PURPOSE OF REVIEW

This review will assess recent clinical and mechanistic data examining glutamine's ability to reduce morbidity and mortality in critical illness.

RECENT FINDINGS

Updated metaanalysis data reveal a significant benefit of glutamine supplementation on mortality, length of stay, and infectious morbidity in critical illness. Recent data support glutamine's use in critically ill patients requiring parenteral nutrition and new data reveal safety and efficacy in head-injured patients. Further, new findings on glutamine's beneficial effect on insulin resistance in critical illness will be reviewed. Recent laboratory data have clarified a number of key mechanistic pathways by which glutamine may improve outcome in critical illness.

SUMMARY

Severe glutamine deficiencies occur rapidly in critical illness. The magnitude of glutamine deficiency is correlated with ICU mortality. Further, metaanalysis reveals glutamine reduces morbidity and mortality in critical illness. It is likely that our new understanding of the molecular pathways by which glutamine acts will lead to insight on how best to utilize glutamine as a nutritional therapy. Presently, randomized, multicenter clinical trials utilizing glutamine as both nutritional replacement and pharmacologic intervention, independent of nutritional needs, are ongoing.