Arginine: Too much of a good thing may be bad!*

Past Experiences for Future Applications of Metabolomics in Critically Ill Patients with Sepsis and Septic Shocks

A disruption of several metabolic pathways in critically ill patients with sepsis indicates that metabolomics might be used as a more precise tool for sepsis and septic shock when compared with the conventional biomarkers. This article provides information regarding metabolomics studies in sepsis and septic shock patients. It has been shown that a variety of metabolomic pathways are altered in sepsis and septic shock, including amino acid metabolism, fatty acid oxidation, phospholipid metabolism, glycolysis, and tricarboxylic acid cycle. Based upon this comprehensive review, here, we demonstrate that metabolomics is about to change the world of sepsis biomarkers, not only for its utilization in sepsis diagnosis, but also for prognosticating and monitoring the therapeutic response. Additionally, the future direction regarding the establishment of studies integrating metabolomics with other molecular modalities and studies identifying the relationships between metabolomic profiles and clinical characteristics to address clinical application are discussed in this article. All of the information from this review indicates the important impact of metabolomics as a tool for diagnosis, monitoring therapeutic response, and prognostic assessment of sepsis and septic shock. These findings also encourage further clinical investigations to warrant its use in routine clinical settings.

Effects of immunonutrition on biomarkers in traumatic brain injury patients in Malaysia: a prospective randomized controlled trial

Background

Head injury is one of the top three diagnosis leading to intensive care unit (ICU) admission in Malaysia. There has been growing interest in using immunonutrition as a mode of modulating the inflammatory response to injury or infection with the aim of improving clinical outcome. The aim of the present study was to evaluate the effect of an immunonutrition on biomarkers (IL-6, glutathione, CRP, total protein and albumin) in traumatic brain injury patients.

Methods

Thirty six patients with head injury admitted to neurosurgical ICU in University Malaya Medical Centre were recruited for this study, over a 6-month period from July 2014 to January 2015. Patients were randomized to receive either an immunonutrition (Group A) or a standard (Group B) enteral feed. Levels of biomarkers were measured at day 1, 5 and 7 of enteral feeding.

Results

Patients in Group A showed significant reduction of IL-6 at day 5 (p < 0.001) with concurrent rise in glutathione levels (p = 0.049). Patients in Group A also demonstrated a significant increase of total protein level at the end of the study (day 7).

Conclusion

These findings indicate the potential of immunonutrition reducing cytokines and increasing antioxidant indices in patients with TBI. However, further studies incorporating patient outcomes are needed to determine its overall clinical benefits.

Trial registration

National Medical Research Register (NMRR) ID: 14–1430-23,171. ClinicalTrials.gov identifier: NCT03166449.

Parenteral or Enteral Arginine Supplementation Safety and Efficacy

Arginine supplementation has the potential to improve the health of patients. Its use in hospitalized patients has been a controversial topic in the nutrition literature, especially concerning supplementation of septic patients. In this article, we review the relevant literature both for and against the use of arginine in critically ill, surgical, and hospitalized patients. The effect of critical illness on arginine metabolism is reviewed, as is its use in septic and critically ill patients. Although mounting evidence supports immunonutrition, there are only a few studies that suggest that this is safe in patients with severe sepsis. The use of arginine has been shown to benefit a variety of critically ill patients. It should be considered for inclusion in combinations of immunonutrients or commercial formulations for groups in whom its benefit has been reported consistently, such as those who have suffered trauma and those in acute surgical settings. The aims of this review are to discuss the role of arginine in health, the controversy surrounding arginine supplementation of septic patients, and the use of arginine in critically ill patients.

A Review of Surgical Nutrition

Malnutrition remains a common problem in surgical patients and is associated with significant morbidity and mortality. It is imperative that all surgical patients undergo nutritional screening on admission to highlight malnourished or at risk patients and implement a nutritional plan. Nutrition can be delivered by oral supplements, enteral or parenteral feeding, the route depending on an individual's requirements and surgical condition. Enteral feeding has largely been regarded as superior to parenteral feeding, as it is cheaper, safer and “more physiological” but studies show this is not always the case. This article reviews the basics of surgical nutrition and assesses the evidence supporting enteral versus parenteral nutrition.

Metabolic support in sepsis and multiple organ failure: more questions than answers

The metabolic support of critically ill patients is a relatively new topic of active research and discussion, and surprisingly little is known about the effects of critical illness on metabolic physiology and activity. The metabolic changes seen in critical illness are highly complex, and how and when to treat them are only just beginning to be determined. Studies have demonstrated that the acute phase and the later phase of critical illness behave differently from a metabolic point of view for many organs, and while many of the alterations in metabolism seen during early critical illness may be appropriate and beneficial responses to cellular stress, whether this is true for all the metabolic alterations in all forms of critical illness is unclear. Currently we face more questions than answers, and further study is needed to elucidate the various components of the metabolic response to acute and chronic critical illness and to develop better techniques to assess and monitor these changes so that we can determine which therapeutic approaches should be used in what combinations and in which patients.

Arginine in the critical care setting

Arginine is a nonessential amino acid in the normal physiological state that becomes conditionally essential during periods of hypermetabolic stress. Recent literature supports the hypothesis that arginine plays an important role in the intermediary metabolism of the critically ill patient. Current critical care literature is conflicting on arginine use in the clinical setting, with some proposing it as a panacea, whereas others report it as poison. Multiple individual reports and at least 5 major meta-analyses using combinations of immune-modulating nutrients have reported mostly beneficial results, but few have evaluated the effects of arginine when given as a single supplemental nutrient. This review attempts to objectively analyze the literature and evaluate the potential role of arginine in the critical care setting.