Taurine Concentrations Decrease in Critically Ill Patients With Shock Given Enteral Nutrition

Taurine in Septic Critically Ill Patients: Plasma versus Blood

Purpose: Sepsis and systemic inflammatory response syndrome (SIRS) encompass various problems throughout the body, and two of its major problems are the creation of oxidative substances in the body and decrease of the body's antioxidant capacity to deal with the stress and organ damage. Optimal enteral nutrition fortified with antioxidant or immunomodulator amino acid is a hot topic concerning sepsis in the critical care setting. Taurine plays a protective role as an antioxidant in cells that is likely to have a protective role in inflammation and cytotoxicity. Methods: In the present study, 20 septic patients and 20 healthy volunteers were enrolled. The blood and plasma taurine levels of the patients on days 1, 3 and 7 were measured. Blood and plasma taurine level and the correlation between them, organ failure, and severity of the disease were assessed. Results: Taurine concentrations in the plasma of the septic patients were significantly lower than control group, and the whole blood concentrations were significantly higher than those of the control group (P<0.001). There was not a significant correlation between the blood and plasma taurine levels in control and septic patients. In addition, there was not any correlation between the severity of the disease, organ failure, mortality, and plasma as well as the blood concentration of taurine. Conclusion: In septic patients, taurine concentration in plasma and blood are low and high, respectively. These concentrations are not linked to each other and not associated with the patients' outcome, and the disease severity, and organ failure.

Beneficial Effect of Immune-Enhanced Enteral Nutrition on Immune Function in Patients With Severe Neurological Diseases: A Single-Center Randomized Controlled Trial

Background: Undernutrition is the main reason for the use of artificial nutrition in patients with severe neurological diseases. However, the clinical and immunological outcomes of enteral nutrition supplemented with immunomodulatory nutrients in these patients remain unclear.

Methods: In this single-center, randomized controlled study, 57 patients with severe neurological diseases were randomly divided into the following two groups according to the type of enteral nutrition they would receive: immune-enhancing (IE) (n = 27) and non-IE (NIE) (n = 30). The IE and NIE groups received enteral nutrition supplemented with immunomodulatory nutrients and standard enteral nutrition, respectively. We compared the nutritional status and the state of cellular immunity between the patients of the two groups. Clinical and immunological variables were evaluated following nutritional treatment.

Results: Feeding intolerance was lower in the IE than that in the NIE group (P = 0.04). However, there were no significant differences between the results of the two groups in terms of length of stay in the intensive care unit or hospital, extubation time, or body mass index (P > 0.05). The CD4+ T-lymphocyte count and CD4⁺/CD8+ ratio in the peripheral blood increased significantly in the IE group. The expression of CD28 activated cell surface markers was higher in the IE than in the NIE group. In addition, increased plasma interferon-γ levels were recorded in the IE group, whereas the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-8, and IL-10 decreased.

Conclusions: Immune-enhanced enteral nutrition could improve the immune status and feeding tolerance in patients with severe neurological diseases.

Trial Registration:www.chictr.org.cn/index.aspx, identifier: ChiCTR-IPR-17013909.

The effects of Taurine supplementation on inflammatory markers and clinical outcomes in patients with traumatic brain injury: a double-blind randomized controlled trial

Background

Traumatic brain injury is a public health concern and is the main cause of death among various types of trauma. The inflammatory conditions due to TBI are associated with unfavorable clinical outcomes. Taurine has been reported to have immune-modulatory effects. Thus, the aim of this study was to survey the effect of taurine supplementation in TBI patients.

Methods

In this study, 32 patients with TBI were randomized into two groups. The treatment group received 30 mg/kg/day of taurine in addition to the Standard Entera Meal and the control group received Standard Entera Meal for 14 days. Prior to and following the intervention, the patients were investigated in terms of serum levels of IL-6, IL-10, hs-CRP and TNF-α as well as APACHEII, SOFA and NUTRIC scores, Glasgow coma scale and weight. In addition, the length of Intensive Care Unit stay, days of dependence on ventilator and 30-day mortality were studied. SPSS software (version 13.0) was used for data analysis.

Results

Taurine significantly decreased the serum levels of IL-6 (p = 0.04) and marginally APACHEII score (p = 0.05). In addition, weight loss was significantly lower in taurine group (p = 0.03). Furthermore, taurine significantly increased the GCS (p = 0.03). The groups were not different significantly in terms of levels of IL-10, hs-CRP, and TNF-α, SOFA and NUTRIC scores, 30-day mortality, length of ICU stay and days of dependence on ventilator.

Conclusion

According to the results of the present study, taurine supplementation can reduce the IL-6 levels as one of the important inflammatory markers in these patients; and enhances the clinical outcomes too.

Trial registration

IRCT, IRCT20180514039657N1. Registered 22 June 2018.

Perioperative changes in the plasma metabolome of patients receiving general anesthesia for pancreatic cancer surgery

Background: Modern anesthesia strives to offer personalized concepts to meet the patient’s individual needs in sight of clinical outcome. Still, little is known about the impact of anesthesia on the plasma metabolome, although many metabolites have been shown to modulate the function of various immune cells, making it particularly interesting in the context of oncological surgery. In this study longitudinal dynamics in the plasma metabolome during general anesthesia in patients undergoing pancreatic surgery were analyzed.

Materials and Methods: Prospective, observational study with 10 patients diagnosed with pancreatic (pre-) malignancy and subjected to elective resection surgery under general anesthesia. Plasma metabolites (n = 630) were quantified at eight consecutive perioperative timepoints using mass spectrometry-based targeted metabolomics.

Results: 39 metabolites significantly changed during the perioperative period. Tryptophan concentrations decreased by 45% with the maximum decrease after anesthesia induction (p = 6.24E-07), while taurine synthesis increased (p = 1.46E-04). Triacylglycerides and lysophosphatidylcholines were significantly reduced with increased liberation of free monounsaturated fatty acids (p = 0.03). Carnitine levels decreased significantly (p = 9.30E-04).

Conclusions: The major finding of this study was perioperative tryptophan depletion and increased taurine synthesis. Both are essential for immune cell function and are therefore of significant interest for perioperative management. Further studies are needed to identify influencing anesthetic factors.

Comprehensive metabolic amino acid flux analysis in critically ill patients

Amino acid (AA) metabolism is severely disturbed in critically ill ICU patients. To be able to make a more scientifically based decision on the type of protein or AA nutrition to deliver in ICU patients, comprehensive AA phenotyping with measurements of plasma concentrations and whole body production (WBP) is needed. Therefore, we studied ICU patients and matched control subjects using a novel pulse isotope method to obtain in-depth metabolic analysis. In 51 critically ill ICU patients (SOFA~6.6) and 49 healthy controls, we measured REE and body composition/phase-angle using BIA. In the postabsorptive state, we collected arterial (ized) blood for CRP and AA. Then, we administered an 8 mL solution containing 18 stable AA tracers as a pulse and calculated WBP. Enrichments: LC-MS/MS and statistics: t-test, ANCOVA. Compared to healthy, critically ill ICU patients had lower phase-angle (p < 0.00001), and higher CRP (p < 0.0001). Most AA concentrations were lower in ICU patients (p < 0.0001), except tau-methylhistidine and phenylalanine. WBP of most AA were significantly (p < 0.0001) higher with increases in glutamate (160%), glutamine (46%), and essential AA. Remarkably, net protein breakdown was lower. There were only weak relationships between AA concentrations and WBP. Critically ill ICU patients (SOFA 8-16) had lower values for phase angle (p = 0.0005) and small reductions of most plasma AA concentrations, but higher tau-methylhistidine (p = 0.0223) and hydroxyproline (p = 0.0028). Remarkably, the WBP of glutamate and glutamine were lower (p < 0.05), as was their clearance, but WBP of tau-methylhistidine (p = 0.0215) and hydroxyproline (p = 0.0028) were higher. Our study in critically ill ICU patients shows that comprehensive metabolic phenotyping was able to reveal severe disturbances in specific AA pathways, in a disease severity dependent way. This information may guide improving nutritional compositions to improve the health of the critically ill patient. CLINICAL TRIAL REGISTRY: Data are from the baseline measurements of study NCT02770092 (URL: https://clinicaltrials.gov/ct2/show/NCT02770092) and NCT03628365 (URL: https://clinicaltrials.gov/ct2/show/NCT03628365).

Clinical Nutrition of Critically Ill Patients in the Context of the Latest ESPEN Guidelines

The group of patients most frequently in need of nutritional support are intensive care patients. This year (i.e., 2019), new European Society for Clinical Nutrition and Metabolism (ESPEN) guidelines of clinical nutrition in intensive care were published, updating and gathering current knowledge on the subject of this group of patients. Planning the right nutritional intervention is often a challenging task involving the necessity of the choice of the enteral nutrition (EN) or parenteral nutrition (PN) route of administration, time of initiation, energy demand, amino acid content and demand as well as the use of immunomodulatory nutrition. The aim of this study was to specify and discuss the basic aspects of the clinical nutrition of critically ill patients recommended by ESPEN guidelines. Clinical nutrition in intensive care seems to be the best-studied type of nutritional intervention. However, meta-analyses and clinical studies comparing EN and PN and their impact on the prognosis of the intensive care patients showed ambiguous results. The nutritional interventions, starting with EN, should be initiated within 24-48 h whereas PN, if recommended, should be implemented within 3-7 days. The recommended method of calculation of the energy demand is indirect calorimetry, however, there are also validated equations used worldwide in everyday practice. The recommended protein intake in this group of patients and the results of insufficient or too high supply was addressed. In light of the concept of immunomodulatory nutrition, the use of appropriate amino acid solutions and lipid emulsion that can bring a positive effect on the modulation of the immune response was discussed.

Taurine administration ablates sepsis induced diaphragm weakness

Infection induced diaphragm weakness is a major contributor to death and prolonged mechanical ventilation in critically ill patients. Infection induced muscle dysfunction is associated with activation of muscle proteolytic enzymes, and taurine is known to suppress proteolysis. We therefore postulated that taurine administration may prevent infection induced diaphragm dysfunction. The purpose of this study was to test this hypothesis using a clinically relevant animal model of infection, i.e. cecal ligation puncture induced sepsis (CLP). Studies were performed on (n = 5-7 mice/group): (a) sham operated controls, (b) animals with sepsis induced by CLP, (c) sham operated animals given taurine (75 mg/kg/d, intraperitoneally), and (d) CLP animals given taurine. At intervals after surgery animals were euthanized, diaphragm force generation measured in vitro, and diaphragm calpain, caspase and proteasomal activity determined. CLP elicited a large reduction in diaphragm specific force generation at 24 h (1-150 Hz, p < 0.001) and taurine significantly attenuated CLP induced diaphragm weakness at all stimulation frequencies (p < 0.001). CLP induced significant increases in diaphragm calpain, caspase and proteasomal activity; taurine administration prevented increases in the activity of all three pathways. In additional time course experiments, diaphragm force generation remained at control levels over 72 h in CLP animals treated with daily taurine administration, while CLP animals demonstrated severe, sustained reductions in diaphragm strength (p < 0.01 for all time points). Our results indicate that taurine administration prevents infection induced diaphragm weakness and reduces activation of three major proteolytic pathways. Because this agent is has been shown to be safe, non-toxic when administered to humans, taurine may have a role in treating infection induced diaphragm weakness. Future clinical studies will be needed to assess this possibility.

Amino Acid Loss during Continuous Venovenous Hemofiltration in Critically Ill Patients

BACKGROUND/OBJECTIVES

During continuous venovenous hemofiltration (CVVH), there is unwanted loss of amino acids (AA) in the ultrafiltrate (UF). Solutes may also be removed by adsorption to the filter membrane. The aim was to quantify the total loss of AA via the CVVH circuit using a high-flux polysulfone membrane and to differentiate between the loss by ultrafiltration and adsorption.

METHODS

Prospective observational study in ten critically ill patients, receiving predilution CVVH with a new filter, blood flow 180 mL/min, and predilution flow 2,400 mL/h. Arterial blood, postfilter blood, and UF samples were taken at baseline, and 1, 8, and 24-h after CVVH initiation, to determine AA concentrations and hematocrit. Mass transfer calculations were used to determine AA loss in the filter and by UF, and the difference between these 2.

RESULTS

The median AA loss in the filter was 10.4 g/day, the median AA loss by UF was 13.4 g/day, and the median difference was -2.9 g/day (IQR -5.9 to -1.4 g/day). For the individual AA, the difference ranged from -1 g/day to +0.4 g/day, suggesting that some AA were consumed or adsorbed and others were generated. AA losses did not significantly change over the 24-h study period.

CONCLUSION

During CVVH with a modern polysulfone membrane, the estimated AA loss was 13.4 g/day, which corresponds to a loss of about 11.2 g of protein per day. Adsorption did not play a major role. However, individual AA behaved differently, suggesting complex interactions and processes at the filter membrane or peripheral AA production.

Redox-Dependent Regulation of Sulfur Metabolism in Biomolecules: Implications for Cardiovascular Health

SIGNIFICANCE

Sulfur-containing amino acids are integral to the molecular mechanisms that underlie many aspects of cellular function and homeostasis, facilitated by reversible changes in the oxidation states of sulfur atoms. Sulfur-containing amino acids are metabolically linked by interacting pathways that impact the one-carbon metabolic cycle and generation of methyl groups, the folate cycle, and maintenance of the major cellular redox buffer; glutathione. Dysregulation of these pathways is associated with diverse pathologies, notably of the cardiovascular (CV) system, which are typically characterized by inappropriate plasma levels of sulfur-containing amino acids. Recent Advances: Perhaps not surprisingly, the cellular redox state has emerged as a major regulator of many enzymatic processes within these metabolic cycles. The metabolism of cysteine can also result in the production of hydrogen sulfide (H₂S), a signaling molecule whose activity is potentially linked to intracellular levels of both reactive oxygen species (ROS) and molecular oxygen.

CRITICAL ISSUES

In most cases, the endogenous physiological sources of ROS that might mediate the interlinked metabolic pathways of sulfur-containing biomolecules remain unknown. However, the family of NADPH oxidases, and Nox4 in particular, is emerging as a likely candidate.

FUTURE DIRECTIONS

This review focuses on the current knowledge of key aspects of sulfur metabolism, which are regulated by redox-based chemical reactions, and the likely intracellular oxidant sources that might mediate this regulation. This knowledge will be important to guide future targeted therapeutic interventions in diverse CV disorders.

Achieving protein targets without energy overfeeding in critically ill patients: A prospective feasibility study

BACKGROUND & AIMS

High protein delivery during early critical illness is associated with lower mortality, while energy overfeeding is associated with higher mortality. Protein-to-energy ratios of traditional enteral formulae are sometimes too low to reach protein targets without energy overfeeding. This prospective feasibility study aimed to evaluate the ability of a new enteral formula with a high protein-to-energy ratio to achieve the desired protein target while avoiding energy overfeeding.

METHODS

Mechanically ventilated non-septic patients received the high protein-to-energy ratio nutrition during the first 4 days of ICU stay (n = 20). Nutritional prescription was 90% of measured energy expenditure. Primary endpoint was the percentage of patients reaching a protein target of ≥1.2 g/kg ideal body weight on day 4. Other endpoints included a comparison of nutritional intake to matched historic controls and the response of plasma amino acid concentrations. Safety endpoints were gastro-intestinal tolerance and plasma urea concentrations.

RESULTS

Nineteen (95%) patients reached the protein intake target of ≥1.2 g/kg ideal body weight on day 4, compared to 65% in historic controls (p = 0.024). Mean plasma concentrations of all essential amino acids increased significantly from baseline to day 4. Predefined gastro-intestinal tolerance was good, but unexplained foul smelling diarrhoea occurred in two patients. In one patient plasma urea increased unrelated to acute kidney injury.

CONCLUSIONS

In selected non-septic patients tolerating enteral nutrition, recommended protein targets can be achieved without energy overfeeding using a new high protein-to-energy ratio enteral nutrition.

Amino acid supplements in critically ill patients

Observational studies have associated a low amino acid intake with adverse outcome of critical illness. Although this finding could theoretically be explained by differences in feeding tolerance related to illness severity, guidelines have recommended to administer sufficient amounts of amino acids from early onwards in the disease course. Recently, however, several high quality randomized controlled trials have not shown benefit by early amino acid supplementation and some trials even found potential harm, thus questioning this recommendation. These negative results could be related to amino acid-induced suppression of autophagy, to the inability to suppress bulk catabolism by exogenous amino acids, or to the administration of an amino acid mixture with an inappropriate composition. Currently, there is no evidence supporting administration of individual amino acid supplements during critical illness and glutamine administration may be harmful. The optimal timing, dose and composition of the amino acid mixture for critically ill patients remain unclear.

Anti-Inflammatory Effect of Taurine in Burned Patients

PURPOSE

Burn induced inflammatory response can be mediated by reactive oxygen metabolites and accompanied by multiple organ dysfunction. Taurine has protective effects against various inflammatory conditions. The aim of this study was to determine the effect of Taurine supplement in thermal burn victims.

METHODS

Thirty patients with severe thermal burns were enrolled in this randomized double-blinded clinical trial. These patients were randomly divided into two equal groups (namely Control and Taurine groups), where both received isocaloric and isonitrogenous formula. One group was supplemented with 50 mg/kg of Taurine per day for a duration of 10 days. Blood samples were obtained to measure Interleukin-10 (IL-10), high-sensitivity C-reactive protein (hs-CRP), and Tumor Necrosis Factor alpha (TNF-α) levels at the beginning and the end of the study.

RESULTS

Change in serum level of IL-10 in Taurine group was more than Control group [-13.60(-31.40, -10.40) compared to -4.00(-20.00, -0.20) respectively; P = 0.030]. This change was significant in patients with more than 30% TBSA of burn [-14.20(-31.40, -10.40) compared to -2.40(-9.60, 0.40) respectively; P = 0.013]. As for the hs-CRP and TNF-α levels, the difference between the two groups were not significant.

CONCLUSION

Based on the results obtained, Taurine supplement showed a positive outcome on anti-inflammatory cytokine IL-10 in all burn patients. This effect was even more significant in patients with higher percentage of burn area. Taurine had no significant effect on the inflammatory marker hs-CRP and the pro-inflammatory cytokine TNF-α level. For a more thorough verification, measurement of a wider range of inflammatory cytokines in more frequent time intervals are suggested.