Nutritional interventions in critical illness

Enteral feeding strategies in patients with acute gastrointestinal injury: From limited to progressive to open feeding

Acute gastrointestinal injury (AGI) is very common in critically ill patients, and its severity is positively correlated with mortality. Critically ill patients with digestive and absorption dysfunction caused by AGI face higher nutritional risks, making nutritional support particularly important. Early enteral nutrition (EN) support is extremely important because it can promote the recovery of intestinal function, protect the intestinal mucosal barrier, reduce microbiota translocation, reduce postoperative complications, shorten hospital stay, and improve clinical prognosis. In recent years, many nutritional guidelines have been proposed for critically ill patients; however, there are few recommendations for the implementation of EN in patients with AGI, and their quality of evidence is low. The use of EN feeding strategies in critically ill patients with AGI remains controversial. The aim of this review was to elaborate on how EN feeding strategies should transition from limited to progressive to open feeding and explain the time window for this transition.

Amino acid metabolism in health and disease

Amino acids are the building blocks of protein synthesis. They are structural elements and energy sources of cells necessary for normal cell growth, differentiation and function. Amino acid metabolism disorders have been linked with a number of pathological conditions, including metabolic diseases, cardiovascular diseases, immune diseases, and cancer. In the case of tumors, alterations in amino acid metabolism can be used not only as clinical indicators of cancer progression but also as therapeutic strategies. Since the growth and development of tumors depend on the intake of foreign amino acids, more and more studies have targeted the metabolism of tumor-related amino acids to selectively kill tumor cells. Furthermore, immune-related studies have confirmed that amino acid metabolism regulates the function of effector T cells and regulatory T cells, affecting the function of immune cells. Therefore, studying amino acid metabolism associated with disease and identifying targets in amino acid metabolic pathways may be helpful for disease treatment. This article mainly focuses on the research of amino acid metabolism in tumor-oriented diseases, and reviews the research and clinical research progress of metabolic diseases, cardiovascular diseases and immune-related diseases related to amino acid metabolism, in order to provide theoretical basis for targeted therapy of amino acid metabolism.

Assessment of the Physical Invasiveness of Peroral Endoscopic Myotomy during the Perioperative Period Based on Changes in Energy Metabolism

A novel treatment method for achalasia of the esophagus and related disorders is known as peroral endoscopic myotomy (POEM). This study aimed to calculate the resting energy expenditure (REE) and evaluated the degree of physical invasiveness based on metabolic changes during the perioperative period of POEM. Fifty-eight patients who underwent POEM were prospectively enrolled; REE, body weight (BW), and basal energy expenditure were measured on the day of POEM, postoperative day 1 (POD 1), and three days after POEM (POD 3). The median REE/BW increased from 19.6 kcal/kg on the day of POEM to 24.5 kcal/kg on POD 1. On POD 3, it remained elevated at 20.9 kcal/kg. The stress factor on POD 1 was 1.20. Among the factors, including the Eckardt score, operation time, and the length of myotomy, the length of myotomy was associated with changes in REE/BW. During the perioperative period of POEM, the level of variation in energy expenditure was lower than that of esophageal cancer surgeries performed under general anesthesia. However, because the length of myotomy is a factor affecting changes in energy expenditure, careful perioperative management is desirable for patients with longer myotomy lengths.

Combined effect of salinity and hypoxia on digestive enzymes and intestinal microbiota in the oyster Crassostrea hongkongensis

Anthropologic activities caused frequent eutrophication in coastal and estuarine waters, resulting in diel-cycling hypoxia. Given global climate change, extreme weather events often occur, thus salinity fluctuation frequently breaks out in these waters. This study aimed to evaluate the combined effects of salinity and hypoxia on intestinal microbiota and digestive enzymes of Crassostrea hongkongensis. Specifically, we sequenced 16 S rRNA of intestinal microbiota and measured the digestive enzymes trypsin (TRS), lipase (LPS) and amylase (AMY) in oysters exposed for 28 days to three salinities (10, 25 and 35) and two dissolved oxygen conditions, normoxia (6 mg/L) and hypoxia (6 mg/L for 12 h, 2 mg/L for 12 h). Oysters in normoxia and salinity of 25 were treated as control. After 28-day exposure, for microbial components, Fusobacteriota, Firmicutes, Bacteroidota, Proteobacteria and Actinobacteriota comprised the majority for all experimental groups. Compared with the control group, the diversity and structure of intestinal microbiota tended to change in all treated groups. The species richness in C. hongkongensis intestine also changed. It was the most significant that high salinity increased Proteobacteria proportion while low salinity and hypoxia increased Fusobacteriota but decreased Proteobacteria, respectively. Additionally, Actinobacteriota was sensitive and changed under environmental stressor (P < 0.01). The prediction results on intestinal microbiota showed that, all functions of oysters were up-regulated to distinct degrees under low/high salinity with hypoxia. According to the KEGG prediction, cellular processes were more active and energy metabolism upregulated, indicating the adaptation of C. hongkongensis to environmental change. Periodical hypoxia and low/high salinity had complex effect on the digestive enzymes, in which the activity of TRS and LPS decreased while AMY increased. High/low salinity and periodical hypoxia can change the secretion of digestive enzymes and influence intestinal microbial diversity and species richness of C. hongkongensis, deducing the chronic adverse effects on the digestive physiology in long-term exposure.

Assessment of physical stress during the perioperative period of endoscopic submucosal dissection

The advantage of endoscopic submucosal dissection (ESD) is that it is less invasive than surgery. ESD is one of the best treatments for older patients as surgery in this age group of patients is difficult. However, it is unclear how much lower the physical stress of ESD is compared with that of surgery. Thus, objective methods are required to assess physical stress in patients who have undergone ESD. The current review of ESD aimed to summarize the recent advancements in the assessment of physical stress during the perioperative period, focusing on changes in energy metabolism and serum opsonic activity (SOA). Based on metabolic changes, resting energy expenditure (REE) was measured using an indirect calorimeter. The stress factor calculated from the REE and the basal energy expenditure computed using the Harris-Benedict equation can be used to assess physical stress. SOA was assessed using the chemiluminescence method, wherein the use of chemiluminescent probes (i.e., lucigenin and luminol) allowed quantification of reactive oxygen species generated by neutrophils. Using an auto luminescence analyzer, the results were evaluated based on the maximum light emission and area under the emission curve. These quantifiable results revealed the minimal invasiveness of ESD.

Influence of Esophageal Endoscopic Submucosal Dissection on the Changes of Energy Metabolism during the Perioperative Period

Esophageal endoscopic submucosal dissection (ESD) is considered to be more complex than gastric ESD. This study aimed to assess the physical invasiveness of esophageal ESD during perioperative periods by measuring resting energy expenditure (REE). The factors affecting REE that could be used to identify patients requiring perioperative management were also investigated. Overall, 75 patients who had undergone esophageal ESD were prospectively enrolled. REE, body weight, and basal energy expenditure were measured on the day of and the day following ESD. The mean REE/body weight was 20.2 kcal/kg/day on the day of ESD and significantly increased to 23.0 kcal/kg/day one day after ESD. The stress factor on the day after ESD was 1.11. White blood cell, neutrophil, and C-reactive protein levels increased on the day after ESD and correlated with the changes in REE. Among the factors including age, body mass index, total resection area, operation time, and sarcopenia, only the total resection area was associated with changes in REE. In conclusion, energy metabolism increases during the perioperative period for esophageal ESD. The increase in the stress factor for esophageal ESD was higher than that in gastric and colorectal ESD. Furthermore, patients with large resection areas require greater attention in perioperative management. 

Role of the posterior mucosal defense barrier in portal hypertensive gastropathy

Portal hypertensive gastropathy (PHG) is a complication of cirrhotic or noncirrhotic portal hypertension. PHG is very important in the clinic because it can cause acute or even massive blood loss, and its treatment efficacy and prognosis are poor. Currently, the incidence of PHG in patients with cirrhosis is 20-80%, but its pathogenesis is complicated and poorly understood. Studies have shown that portal hypertension can cause changes in gastric mucosal microcirculation hemodynamics, leading to changes in gastric mucosal histology and function and thereby weakening the mucosal defense barrier. However, no specific drug treatment plans are currently available. This article reviews the current literature to further our understanding of the mechanism underlying PHG and the relationship between PHG and the posterior mucosal defense barrier and to explore new therapeutic targets.

Arginine-dependent immune responses

A growing body of evidence indicates that, over the course of evolution of the immune system, arginine has been selected as a node for the regulation of immune responses. An appropriate supply of arginine has long been associated with the improvement of immune responses. In addition to being a building block for protein synthesis, arginine serves as a substrate for distinct metabolic pathways that profoundly affect immune cell biology; especially macrophage, dendritic cell and T cell immunobiology. Arginine availability, synthesis, and catabolism are highly interrelated aspects of immune responses and their fine-tuning can dictate divergent pro-inflammatory or anti-inflammatory immune outcomes. Here, we review the organismal pathways of arginine metabolism in humans and rodents, as essential modulators of the availability of this semi-essential amino acid for immune cells. We subsequently review well-established and novel findings on the functional impact of arginine biosynthetic and catabolic pathways on the main immune cell lineages. Finally, as arginine has emerged as a molecule impacting on a plethora of immune functions, we integrate key notions on how the disruption or perversion of arginine metabolism is implicated in pathologies ranging from infectious diseases to autoimmunity and cancer.

Protocol for a multicentre longitudinal mixed-methods study: feeding and survivorship outcomes in previously healthy young paediatric Intensive care survivors (the PIES Study)

INTRODUCTION

An admission to paediatric intensive care unit (PICU) is associated with multiple physical and environmental stressors, often involving many negative and painful oral experiences. Evidence from children with complex medical conditions suggests that feeding difficulties post-PICU stay are common, causing significant parental anxiety. Adult intensive care unit (ICU) survivor studies suggest feeding issues lasting up to 3 months post-discharge from ICU. There is, however, a paucity of evidence regarding feeding outcomes for previously healthy children following a PICU admission and whether painful oral experiences during an admission contribute to feeding difficulties post-discharge, negatively impacting on parental/caregiver anxiety.

METHODS AND ANALYSIS

This longitudinal mixed-methods study will explore the impact of feeding difficulties, identifying any clinical risk factors during the first 6 months of PICU discharge in previously healthy young children (≤4 years). Parents/caregivers of children will be asked to complete questionnaires relating to: feeding difficulties, parental/caregiver stress, and child and parental/caregivers' feeding behaviours at the point of PICU discharge, 1, 3 and 6 months post-discharge. Parents/caregivers will be invited to participate in qualitative semistructured interviews at 3 and 6 months post-PICU discharge exploring parental/caregiver experiences of feeding their child after PICU. Statistical analysis of the survey data will consist of descriptive and inferential statistics, plus qualitative analysis of any free text comments using thematic analysis.

ETHICS AND DISSEMINATION

This study will provide an insight and increase our understanding of the prevalence of feeding difficulties in previously healthy children admitted to PICU and parental/caregiver experiences. Multiple methods will be used to ensure that the findings are effectively disseminated to service users, clinicians, policy and academic audiences. The study has full ethical approval from the National Health Service Research Ethics Committee (Ref: 20/YH/0160) and full governance clearance.

Intermittent versus continuous enteral nutrition on feeding intolerance in critically ill adults: A meta-analysis of randomized controlled trials

OBJECTIVES

Enteral formula delivery strategy is an important part of enteral nutrition. We aimed to synthesize up-to-date studies to clarify the effects of intermittent versus continuous feeding on feeding intolerance during enteral nutrition in critically ill adults.

DESIGN

A meta-analysis of randomized controlled trials.

DATA SOURCES

Embase, PubMed, Information Sciences Institute Web of Science, CINAHL EBSCO, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database, China National Knowledge Infrastructure databases were searched from inception to 17th of June 2020.

REVIEW METHODS

The Cochrane "risk of bias" tool was used to assess the quality of individual studies, and the quality of each outcome was assessed by GRADE approach. Fixed or random effect meta-analysis was used pending the presence of heterogeneity. Dichotomous data synthesis was presented as risk ratio and 95% confidence interval, and quantitative data synthesis was shown as mean difference and 95% confidence interval.

RESULTS

Fourteen trials with 1025 critically ill adults were included in the meta-analysis. We found that intermittent feeding could significantly increase the occurrence of feeding intolerance (risk ratio = 1.64, 95% confidence interval = 1.23 to 2.18, P < 0.001) compared with continuous feeding, as well as the incidence of high gastric volume (risk ratio = 3.62, 95% confidence interval = 1.43-9.12, P = 0.006) and aspiration (risk ratio = 3.29, 95% confidence interval = 1.18-9.16, P = 0.02) in > 1-week trial duration, while constipation rate was reduced in intermittent feeding group (risk ratio = 0.66, 95% confidence interval = 0.45-0.98, P = 0.04). Patients in intermittent feeding group received more calories compared with continuous feeding group (mean difference = 184.81, 95% confidence interval = 56.61-313.01, P = 0.005). The quality of all evidence synthesis was "low" or "very low".

CONCLUSIONS

In critically ill adults, continuous feeding was associated with lower overall incidence of feeding intolerance, especially in high gastric volume and aspiration. However, decreased constipation incidence and more calorie intake were observed in intermittent feeding group. Because quality of the synthesized evidence was "low" or "very low", there is considerable uncertainty about this estimate.

The Impact of Perioperative Glutamine-supplemented Parenteral Nutrition on Outcomes of Patients Undergoing Abdominal Surgery: A Meta-analysis of Randomized Clinical Trials

The objective of this study was to evaluate the impact of perioperative glutamine-supplemented parenteral nutrition (GLN-PN) on clinical outcomes in patients undergoing abdominal surgery. MEDLINE, EMBASE, and the Cochrane Controlled Clinical Trials Register were searched to retrieve the eligible studies. Eligible studies were randomized controlled trials (RCTs) that compared the effect of GLN-PN and standard PN on clinical outcomes in patients undergoing abdominal surgery. Clinical outcomes of interest were postoperative mortality, length of hospital stay, morbidity of infectious complication, and cumulative nitrogen balance. Statistical analysis was conducted by RevMan 5.0 software from the Cochrane Collaboration. Sixteen RCTs with 773 patients were included in this meta-analysis. The results showed a significant decrease in the infectious complication rates of patients undergoing abdominal surgery receiving GLN-PN (risk ratio [RR], 0.48; 95% confidence interval [CI], 0.32 to 0.72; P = 0.0004). The overall effect indicated glutamine significantly reduced the length of hospital stay in the form of alanyl-glutamine (weighted mean difference [WMD], -3.17; 95% CI, -5.51 to -0.82; P = 0.008) and in the form of glycyl-glutamine (WMD, -3.40; 95% CI, -5.82 to -0.97; P = 0.006). A positive effect in improving postoperative cumulative nitrogen balance was observed between groups (WMD, 7.40; 95% CI, 3.16 to 11.63; P = 0.0006), but no mortality (RR, 1.52; 95% CI, 0.21 to 11.9; P = 0.68). Perioperative GLN-PN is effective and safe to shorten the length of hospital stay, reduce the morbidity of postoperative infectious complications, and improve nitrogen balance in patients undergoing abdominal surgery.

Plant- and Nutraceutical-based Approach for the Management of Diabetes and its Neurological Complications: A Narrative Review

Diabetes is an important metabolic disease affecting many organs and systems in the body. The nervous system is one of the body systems affected by diabetes and neuropathic complications are troublesome in diabetic patients with many consequences. As diabetes has deleterious influences almost on bodily systems, an integrative approach seems to be necessary accepting the body as a whole and integrating body systems with lifestyle and living environment. Like some traditional health systems such as Ayurveda, integrative approach includes additional modalities to overcome both diabetes and diabetic complications. In general, these modalities consist of nutraceuticals and plant products. Prebiotics and probiotics are two types of nutraceuticals having active ingredients, such as antioxidants, nutrient factors, microorganisms, etc. Many plants are indicated for the cure of diabetes. All of these may be employed in the prevention and in the non-pharmacological management of mildto- moderate diabetes. Severe diabetes should require appropriate drug selection. Being complementary, prebiotics, probiotics, plants and exercise may be additive for the drug therapy of diabetes. Similarly, there are complementary approaches to prevent and cure neurological and/or behavioral manifestations of diabetes, which may be included in therapy and prevention plans. A scheme is given for the prevention and therapy of comorbid depression, which is one of the most common behavioral complications of diabetes. Within this scheme, the main criterion for the selection of modalities is the severity of diseases, so that personalized management may be developed for diabetic patients using prebiotics and probiotics in their diets, plants and drugs avoiding possible interactions.

Estimation of perioperative invasiveness of colorectal endoscopic submucosal dissection evaluated by energy metabolism

The aim of this study was to assess the perioperative invasiveness of endoscopic submucosal dissection for colorectal cancer quantitatively by using energy metabolism. In fifty-three patients who underwent endoscopic submucosal dissection for colorectal cancer, resting energy expenditure using an indirect calorimeter, body weight and basal energy expenditure using the Harris–Benedict equation before and after endoscopic submucosal dissection. Resting energy expenditure/body weight and resting energy expenditure/basal energy expenditure were 19.7 ± 2.5 kcal/kg/day and 0.96 ± 0.12 on the day of endoscopic submucosal dissection, whereas one day after the endoscopic submucosal dissection they increased to 21.0 ± 2.9 kcal/kg/day and 1.00 ± 0.13 (p<0.001 and p<0.05, respectively). The stress factor on the postoperative day 1 was computed as 1.06. The increase was lower comparing with that experienced for surgery, suggesting that the perioperative invasiveness of colorectal endoscopic submucosal dissection is lower in comparison to that during surgery. Furthermore, in spite of technical difficulty, stress factor of colorectal endoscopic submucosal dissection was approximately equal to that of gastric endoscopic submucosal dissection. (The study of the resting energy metabolism and stress factor using an indirect calorimeter in the perioperative period of endoscopic operation: UMIN000027135)

High-Protein Hypocaloric Nutrition for Non-Obese Critically Ill Patients

High-protein hypocaloric nutrition, tailored to each patient's muscle mass, protein-catabolic severity, and exogenous energy tolerance, is the most plausible nutrition therapy in protein-catabolic critical illness. Sufficient protein provision could mitigate the rapid muscle atrophy characteristic of this disease while providing urgently needed amino acids to the central protein compartment and sites of tissue injury. The protein dose may range from 1.5 to 2.5 g protein (1.8-3.0 g free amino acids)/kg dry body weight per day. Nutrition should be low in energy (≈70% of energy expenditure or ≈15 kcal/kg dry body weight per day) because efforts to match energy provision to energy expenditure are physiologically irrational, risk toxic energy overfeeding, and have repeatedly failed in large clinical trials to demonstrate clinical benefit. The American Society for Parenteral and Enteral Nutrition currently suggests high-protein hypocaloric nutrition for obese critically ill patients. Short-term high-protein hypocaloric nutrition is physiologically and clinically sensible for most protein-catabolic critically ill patients, whether obese or not.

Enteral/Parenteral Nutrition in Foals and Adult Horses Practical Guidelines for the Practitioner

Nutritional support is an important adjunct to medical therapy in the sick, injured, or debilitated equine patient. What is not clear is the optimal route, composition, or amounts of support. The enteral route should be chosen whenever possible to maximize the benefits to the gastrointestinal tract and the patient as a whole. Complete or partial parenteral nutrition is most useful as a bridge during recovery and transition to enteral feeding in the horse. The reader is encouraged to consider nutritional support whether enteral or parenteral in any anorexic, chronically debilitated, or sick equine patient.

Energy metabolism during the perioperative period of gastric endoscopic submucosal dissection

The aim of this study was to investigate the change in the energy metabolism and invasiveness in the perioperative period of endoscopic submucosal dissection for early gastric cancer. Fifty-two consecutive patients were enrolled into the study between July 2013 and May 2014 and examined resting energy expenditure using an indirect calorimeter, body weight and basal energy expenditure using the Harris-Benedict equation before and after endoscopic submucosal dissection. Resting energy expenditure/body weight and resting energy expenditure/basal energy expenditure were 20.2 ± 3.0 kcal/kg/day and 0.96 ± 0.11 on the day of endoscopic submucosal dissection, whereas one day after the endoscopic submucosal dissection they were 21.7 ± 3.2 kcal/kg/day and 1.03 ± 0.14, showing significant increases (p<0.001, respectively). The stress factor on the postoperative day 1 was computed as 1.07. This increase was low in comparison to that experienced for surgery, suggesting that the degree of perioperative invasiveness in patients receiving endoscopic submucosal dissection is lower in comparison to that during surgery (The study of the resting energy metabolism and stress factor using an indirect calorimeter in the perioperative period of endoscopic operation: UMIN000027135).

Protein Requirements for Critically Ill Patients With Renal and Liver Failure

Diseases leading to critical illness induce proteolysis resulting in muscle wasting and negative nitrogen balance. Muscle wasting has been associated with poor intensive care unit (ICU)-related outcomes, including an increased risk for mortality. Acute kidney injury (AKI) represents a common organ dysfunction associated with ICU-related disorders, such as sepsis, trauma, and respiratory failure. AKI and renal replacement therapy lead to amino acid loss. Decompensated liver cirrhosis (DLC) and acute liver failure (ALF) represent more severe forms of liver dysfunction leading to ICU admission. DLC and ALF are associated with proteolysis and amino acid loss. AKI, DLC, and ALF uniquely contribute to negative nitrogen balance. The purpose of this review is to outline proteolysis associated with critical illness; define specific protein abnormalities in AKI, DLC, and ALF; define protein requirements in AKI, DLC, and ALF; and discuss barriers associated with optimal protein supplementation in these disorders.

Comparison of Two Different Enteral Nutrition Protocol in Critically Ill Patients

OBJECTIVE

In this study, two enteral nutrition protocols with different gastric residual volumes (GRVs) and different monitoring intervals were compared with respect to gastrointestinal intolerance findings in intensive care unit (ICU) patients.

METHODS

The study was carried out prospectively in 60 patients in the anaesthesiology and reanimation ICU under mechanical ventilation support, who were scheduled to take enteral feeding. Patients were sequentially divided into two groups: Group 1, GRV threshold of 100 mL, and monitoring interval of 4 hours, and Group 2, GRV threshold of 200 mL, monitoring interval of 8 hours. To test the significant difference between the groups, Student's t test, chi-square text and Fisher exact test were used.

RESULTS

In Group 1, 3.3% vomiting, 6.6% diarrhoea was observed; in Group 2, 16.6% vomiting, 10% diarrhoea. In terms of total intolerance (vomiting and/or diarrhoea) of the two groups, the incidence was significantly higher in Group 2 (33.3%) than in Group 1 (10%) (p=0.02).

CONCLUSION

According to the results of the study, a lower gastrointestinal intolerance rate was detected in the GRV threshold 100 mL, monitoring interval for 4 hours protocol (Group 1) than in GRV threshold 200 mL, monitoring interval for 8 hours protocol (Group 2); Group 1 may be preferred renovation.

Amino acid concentrations in critically ill children following cardiac surgery*

OBJECTIVE

Guidelines for administering amino acids to critically ill children are largely based on uncontrolled observational studies and expert opinion, without support from rigorous outcome studies. Also, data on circulating amino acid concentrations during critical illness are scarce. We thoroughly studied the time profiles of circulating amino acid concentrations in critically ill children who received standard nutritional care according to international guidelines.

DESIGN

This is a subanalysis of pediatric critically ill patients included in a large (n = 700) randomized controlled study on intensive insulin therapy.

SETTING

The study was conducted at a university hospital PICU.

PATIENTS

We studied 100 patients in PICU for at least 3 days following cardiac surgery.

INTERVENTIONS

Patients were assigned to intensive insulin therapy targeting normal-for-age fasting blood glucose concentrations or insulin infusion only to prevent excessive hyperglycemia.

MEASUREMENTS AND MAIN RESULTS

Plasma amino acid concentrations were measured at admission, day 3, and day 7 in PICU. At admission, the concentrations of most amino acids were comparable to those reported for healthy children. Total amino acid concentrations remained stable during ICU stay, but individual amino acids showed different time profiles with eight of them showing an increase and five a decrease. Nonsurviving children had higher total amino acid concentrations and individual amino acids compared with survivors at admission and/or during ICU stay. Intensive insulin therapy lowered the concentrations of total amino acids and several individual amino acids. Neonates showed somewhat different amino acid profiles with rather increased concentrations from baseline with time in ICU for total amino acids and several individual amino acids as compared with older infants and children.

CONCLUSIONS

Circulating amino acid concentrations in critically ill children after cardiac surgery differ according to survival status, blood glucose control with intensive insulin therapy, and age.

Antioxidant properties of glutamine and its role in VEGF-Akt pathways in portal hypertension gastropathy

AIM

To investigate the effects of glutamine on oxidative/nitrosative stress and the vascular endothelial growth factor (VEGF)-Akt-endothelial nitric oxide synthase (eNOS) signaling pathway in an experimental model of portal hypertension induced by partial portal vein ligation (PPVL).

METHODS

Portal hypertension was induced by PPVL. The PPVL model consists of a partial obstruction of the portal vein, performed using a 20 G blunt needle as a guide, which is gently removed after the procedure. PPVL model was performed for 14 d beginning treatment with glutamine on the seventh day. On the fifteenth day, the mesenteric vein pressure was checked and the stomach was removed to test immunoreactivity and oxidative stress markers. We evaluated the expression and the immunoreactivity of proteins involved in the VEGF-Akt-eNOS pathway by Western blotting and immunohistochemical analysis. Oxidative stress was measured by quantification of the cytosolic concentration of thiobarbituric acid reactive substances (TBARS) as well as the levels of total glutathione (GSH), superoxide dismutase (SOD) activity, nitric oxide (NO) production and nitrotyrosine immunoreactivity.

RESULTS

All data are presented as the mean ± SE. The production of TBARS and NO was significantly increased in PPVL animals. A reduction of SOD activity was detected in PPVL + G group. In the immunohistochemical analyses of nitrotyrosine, Akt and eNOS, the PPVL group exhibited significant increases, whereas decreases were observed in the PPVL + G group, but no difference in VEGF was detected between these groups. Western blotting analysis detected increased expression of phosphatidylinositol-3-kinase (PI3K), P-Akt and eNOS in the PPVL group compared with the PPVL + G group, which was not observed for the expression of VEGF when comparing these groups. Glutamine administration markedly alleviated oxidative/nitrosative stress, normalized SOD activity, increased levels of total GSH and blocked NO overproduction as well as the formation of peroxynitrite.

CONCLUSION

Glutamine treatment demonstrated to reduce oxidative damage but does not reduce angiogenesis induced by PH in gastric tissue, demonstrating a beneficial role for the PI3K-Akt-eNOS pathway.

The Inflammatory Modulation Effect of Glutamine-Enriched Total Parenteral Nutrition in Postoperative Gastrointestinal Cancer Patients

The objective of this study is to explore the inflammatory modulation effect of glutamine-enriched total parenteral nutrition (TPN) by investigating the alterations of inflammation-related cytokines in gastrointestinal (GI) cancer patients postoperatively. Fifty GI cancer patients received postoperative 7 days of isocaloric and isonitrogenous TPN after operation. They were randomly divided to receive either glutamine-enriched TPN or standard TPN. The inflammation-related cytokines including interleukin-6, interleukin-10, and tumor necrosis factor-α were also determined. Records of nutritional assessments, inflammatory status, and postoperative complications were compared between the two groups. Of 50 enrolled patients, 25 patients were classified as the intervention group, and the control group also comprised 25 patients. The differences of gender, age, primary GI malignancies, and hematological and biochemical data between the two compared groups were not statistically significant (all P > 0.05). Compared with standard TPN, a higher serum prealbumin level and better nitrogen balance were observed in glutamine-enriched TPN ( P = 0.039 and 0.048 respectively). A significantly lower serum interleukin-6 level was found in comparing glutamine-enriched with standard TPN ( P = 0.01), but not in interleukin-10 ( P = 0.374) and tumor necrosis factor-α levels ( P = 0.653). Moreover, a significant lower serum C-reactive protein level was detected in glutamine-enriched TPN compared with standard TPN ( P = 0.013). Indeed, four cases of postoperative infectious complications were noted in the control group, but no postoperative infectious complications were observed in the interventional group ( P = 0.037). Our present study shows that glutamine-enriched TPN may be beneficial in improving the inflammatory status and decreasing the infectious morbidity in postoperative GI cancer patients.

Potential for amino acids supplementation during inflammatory bowel diseases

The pathophysiology of inflammatory bowel diseases (IBDs) is multifactorial and involves interactions of gut luminal content with mucosal barrier and especially immune cells. Malnutrition is a frequent issue during IBD flares, especially in Crohn's disease (CD) patients, and nutritional support is frequently used to treat malnutrition but also in an attempt to modulate intestinal inflammation. The use of oral or enteral nutrition intervention in IBDs may be effective, alone or in combination with drugs, to achieve and maintain remission. However, standard diets are less effective than new-generation biotherapies and could be improved by supplementation with specific immunomodulatory amino acids. Experimental studies evaluating glutamine, the preferential substrate for enterocytes, are promising. Some clinical studies with oral glutamine in CD are until now disappointing, but new formulations and targeting could enhance glutamine efficacy at the site of mucosal lesions. The role of arginine, involved in nitric oxide and polyamines synthesis, still remains debated. However, the effects of these amino acids in IBD have been poorly documented in humans. Other candidates like glycine, cysteine, histidine, or taurine should also be evaluated in the future.

Blood glucose control among critically ill patients with brain injury

OBJECTIVE

To evaluate the incidence of hypoglycemia, hyperglycemia and blood glucose (BG) variability in brain-injured patients and their association with clinical outcomes.

METHODS

Retrospective cohort study of brain-injured patients admitted to an 11-bed neurosciences intensive care unit (ICU) from January 1 to December 31, 2003.

RESULTS

We included 606 patients. Mean age was 52.3 years, 60.6% were male, 11.9% had diabetes mellitus, and 64% were post-operative. Seventy-five (12.4%) received intensive insulin therapy (IIT) for a median (IQR) 72 (24-154) hours. Hypoglycemia and hyperglycemia occurred in 4.6% (96.4% receiving IIT) and 9.6% (77.6% receiving IIT). Median number of episodes per patient was 3 (75% with > or = 2) and 4 (81% with > or = 2) for hypoglycemia and hyperglycemia. Variable glycemic control occurred in 3.8% (100% receiving IIT) with median number of 13 episodes per patient. In-hospital mortality was 16.7%, median (IQR) ICU and hospital lengths of stay were 2 (1-5) and 8 (3-19) days. Hypoglycemia, hyperglycemia and BG variability showed non-significant but consistent associations with hospital mortality and prolonged lengths of ICU and hospital stay. The rate of recurrence of episodes showed stronger and significant associations with outcome, in particular for BG variability and hyperglycemia.

CONCLUSIONS

Hypoglycemia, hyperglycemia and BG variability are relatively common in brain-injured patients and are associated with IIT. An increased frequency of episodes, in particular for BG variability and hyperglycemia, was associated with greater risk of both hospital death and prolonged duration of stay.

Sustained low efficiency dialysis in the continuous mode (C-SLED): dialysis efficacy, clinical outcomes, and survival predictors in critically ill cancer patients

BACKGROUND AND OBJECTIVES

Oliguric, hypotensive patients who require large amounts of fluids may benefit from sustained low-efficiency dialysis performed continuously (C-SLED). C-SLED through higher clearance may improve survival, or through greater nutritional loss may worsen survival. No studies have assessed survival on C-SLED. The objective was to examine patient outcomes and survival predictors on C-SLED.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The data of 199 consecutive cancer patients treated with C-SLED were analyzed. The median duration of C-SLED was 50 h. With 48 h of C-SLED, the blood urea nitrogen (BUN) and serum creatinine levels had decreased by 80% and 73%, respectively. The mean arterial pressure (MAP) was maintained despite higher ultrafiltration and reduced vasopressor use. The 30-d mortality rate was 65%. Despite excellent dialysis, the sequential organ failure assessment (SOFA) score remained predictive of mortality. In the univariate model, higher SOFA scores and lower values for MAP, blood pH, and serum albumin and creatinine levels were associated with higher mortality. Administration of total parenteral nutrition (TPN) was, however, associated with lower mortality.

RESULTS

In the multivariate model, the higher SOFA score and lower blood pH, MAP and C-SLED duration were associated with higher mortality. In a subset analysis of 129 patients who received C-SLED for at least 48 h, those with higher BUN levels, which were associated with higher TPN infusion, had a lower mortality risk.

CONCLUSION

This first detailed report on C-SLED indicates that C-SLED can be effective and suggests a link between nutrition and survival.

Arginine, scurvy and Cartier's "tree of life"

Several conifers have been considered as candidates for "Annedda", which was the source for a miraculous cure for scurvy in Jacques Cartier's critically ill crew in 1536. Vitamin C was responsible for the cure of scurvy and was obtained as an Iroquois decoction from the bark and leaves from this "tree of life", now commonly referred to as arborvitae. Based on seasonal and diurnal amino acid analyses of candidate "trees of life", high levels of arginine, proline, and guanidino compounds were also probably present in decoctions prepared in the severe winter. The semi-essential arginine, proline and all the essential amino acids, would have provided additional nutritional benefits for the rapid recovery from scurvy by vitamin C when food supply was limited. The value of arginine, especially in the recovery of the critically ill sailors, is postulated as a source of nitric oxide, and the arginine-derived guanidino compounds as controlling factors for the activities of different nitric oxide synthases. This review provides further insights into the use of the candidate "trees of life" by indigenous peoples in eastern Canada. It raises hypotheses on the nutritional and synergistic roles of arginine, its metabolites, and other biofactors complementing the role of vitamin C especially in treating Cartier's critically ill sailors.

Down-regulation of the hepatic selenoprotein biosynthesis machinery impairs selenium metabolism during the acute phase response in mice

The acute-phase response (APR) is characterized by an impaired metabolism of the essential trace element selenium (Se). Moreover, low-Se concentrations correlate to mortality risk in sepsis. Therefore, we analyzed the expression of the central Se transport and storage protein selenoprotein P (Sepp1) during an APR in mice. Serum Se and Sepp1 concentrations declined in parallel after injection of lipopolysaccharide to 50 and 39% of control-injected littermates, respectively. This negative APR proceeded largely independent from hepatic Sepp1 transcript concentrations. Instead, we identified a set of hepatic transcripts involved in Se metabolism, which declined coordinately during the APR, including the selenocysteine-specific elongation factor (EFsec), selenophosphate-synthetase 2 (Sephs2), selenocysteine-tRNA[Ser]Sec synthase (SecS), and phosphoseryl-tRNA[Ser]Sec kinase (Pstk). Pstk reacted most strongly and qualified as a new limiting factor for Sepp1 biosynthesis in siRNA-mediated knockdown experiments in hepatocytes in culture. Analogous experiments were performed with mice transgenic for hepatocyte-specific human Sepp1 cDNA to verify this hypothesis. Similar kinetics and effect sizes of Sepp1 expression were observed as before in wild-type mice. We conclude that hepatic translation of Sepp1 mRNA is specifically impaired during the APR. This deficit disrupts regular Se metabolism, transport, and supply to peripheral tissues and likely aggravates the pathological status.

Changes in adipose tissue gene expression and plasma levels of adipokines and acute-phase proteins in patients with critical illness

Insulin resistance develops rapidly during critical illness. The release of adipokines from adipose tissue is thought to play a key role in the development of insulin resistance, as are elevated levels of acute-phase proteins. The aim of this study was to identify changes in adipose tissue gene expression and plasma levels of adipokines and acute-phase proteins during critical illness. From 8 patients with subarachnoidal hemorrhage, consecutive blood samples and adipose tissue biopsies were obtained at 3 time points, twice during intensive care (1-2 days [IC1] and 7-9 days after subarachnoidal hemorrhage) and once after 8 months (recovery). The patients received a continuous insulin infusion to maintain normal glucose levels reflecting insulin resistance. The DNA microarray analysis showed increased zink-alpha2 glycoprotein (ZAG) and phospholipase A2, group IIA messenger RNA levels during intensive care compared with recovery (P < .05). Real-time polymerase chain reaction confirmed the increased expression of ZAG and phospholipase A2, group IIA. Plasma levels of ZAG, serum amyloid A, and C-reactive protein were higher at 7 to 9 days after subarachnoidal hemorrhage compared with either IC1 or recovery (P = .0001); and plasma levels of retinol-binding protein 4 and adiponectin were lower at IC1 compared with recovery (P = .05). The described changes in adipose tissue gene expression and plasma levels of adipokines and acute-phase proteins may influence the development of insulin resistance during critical illness.

Combined glutamine and arginine decrease proinflammatory cytokine production by biopsies from Crohn's patients in association with changes in nuclear factor-kappaB and p38 mitogen-activated protein kinase pathways

Glutamine (Gln) and arginine (Arg) are conditionally essential amino acids with immunomodulatory properties. The aim of the study was to assess the effects of Gln and Arg alone or in combination on cytokine release by cultured colonic biopsies from patients with active Crohn's disease (CD). Ten consecutive patients [mean (range) age 26 (18-39) y] with active colonic CD (mean CD activity index: 383.7 +/- 129.8) were prospectively included in the study. Eight colonic biopsies were obtained via a colonoscopy and incubated during 18 h with low (physiological) or high (pharmacological) doses of Arg (0.1 or 2 mmol/L designated as Arg(low) or Arg(high), respectively) and Gln (0.6 or 10 mmol/L designated as Gln(low) or Gln(high), respectively). The concentrations of cytokines [interleukin (IL)-4, IL-10, IL-8, IL-6, tumor necrosis factor-alpha (TNFalpha), IL-1beta, interferon-gamma) were assessed by ELISA, and nitric oxide (NO) production was evaluated by Griess assay. Nuclear factor (NF)-kappaB p65 subunit, inhibitor of NFkappaB-alpha, and p38 mitogen-activated protein kinase (MAPK) were assessed by immunoblotting. Arg(high)/Gln(high) decreased the production of TNFalpha, IL-1beta, IL-8, and IL-6 (each P < 0.01). Arg(low)/Gln(high) decreased IL-6 and IL-8 production (both P < 0.01), whereas Arg(high)/Gln(low) did not affect cytokine and NO production. Arg(low)/Gln(high) and Arg(high)/Gln(high) decreased NF-kappaB p65 subunit expression, whereas p38 MAPK was decreased only by Arg(high)/Gln(high). Combined pharmacological doses of Arg and Gln decreased TNFalpha and the main proinflammatory cytokines release in active colonic CD biopsies via NF-kappaB and p38 MAPK pathways. These results could be the basis of prospective studies evaluating the effects of enteral supply of combined Arg and Gln during active CD.

Altered pharmacology in the Intensive Care Unit patient

Critically ill patients, not infrequently present alterations of physiological parameters that determine the success/failure of therapeutic interventions as well as the final outcome. Sepsis and polytrauma are two of the most common and complex syndromes occurring in Intensive Care Unit (ICU) and affect drug absorption, disposition, metabolism and elimination. Pharmacological management of ICU patients requires consideration of the unique pharmacokinetics associated with these clinical conditions and the likely occurrence of drug interaction. Rational adjustment in drug choice and dosing contributes to the appropriateness of treatment of those patients.

Protein and the critically ill; do we know what to give?

The National Institute for Health and Clinical Excellence (NICE) has recommended that nutrition support in seriously-ill or injured patients should start at 50% of the estimated target energy and protein needs. This recommendation has caused some concern, since taking the NICE approach leads to these sick individuals receiving an initial N provision of only 0.12 g N/kg per d, as opposed to levels of approximately 0.25 g N/kg per d that have been widely recommended by other expert groups. The basis of the recommendation for higher levels of N provision is that feeding at levels of >/=0.25 g N/kg per d reduces the inevitable net N loss of catabolism and hence minimises overall lean tissue wasting. However, although it has always been assumed that better N balance must equate with better outcome, there are teleological arguments that question the wisdom of providing more N to sicker patients and studies that imply that best N balance might not equate with best clinical progress. Furthermore, current evidence suggests that in most critical illness low initial intakes of both energy and N lead to improved survival. It therefore seems logical to aim, in the first instance, to feed the seriously ill at only modest levels. Further research is required to determine whether lower-energy higher-N feeding would prove better or worse than this approach in terms of clinical benefit rather than just better N retention. Investigations to explore the use of feeds that are specifically designed to match the amino acid needs of illness are also required.

Oxidation–reduction potential and paraoxonase–arylesterase activity in trauma patients

The amount of oxidative stress in severely traumatized patients is usually based on various individual parameters such as total antioxidants and lipid peroxidation. Serial measurements of plasma oxidation-reduction potential (ORP) in severely traumatized patients as a simple mean of assessing overall oxidative stress is described. Serial whole blood samples were obtained from multi-trauma patients (N=39) and healthy individuals (N=10). Plasma ORP in multi-trauma patients increased during the first few days of hospitalization and approached normal ORP levels upon discharge. On the ORP maxima day (5.8 days+/-0.5 SEM), a statistically significant decrease (p<0.05) was observed for negative acute phase reactants such as plasma paraoxonase-arylesterase (PON-AE) activity and total plasma protein in comparison with admission plasma levels. Monitoring ORP could be a useful tool for assessing the degree of oxidative stress, inflammation, severity of injury, and potential efficacy of treatment.