BackgroundNutrition guidelines recommendations differ on the use of parenteral nutrition (PN), and existing clinical trial data are inconclusive. Our recent observational data show that amounts of energy/protein received early in the intensive care unit (ICU) affect patient mortality, particularly for inadequate nutrition intake in patients with body mass indices (BMIs) of <25 or >35. Thus, we hypothesized increased nutrition delivery via supplemental PN (SPN) + enteral nutrition (EN) to underweight and obese ICU patients would improve 60-day survival and quality of life (QoL) versus usual care (EN alone).MethodsIn this multicenter, randomized, controlled pilot trial completed in 11 centers across four countries, adult ICU patients with acute respiratory failure expected to require mechanical ventilation for >72 hours and with a BMI of <25 or ≥35 were randomized to receive EN alone or SPN + EN to reach 100% of their prescribed nutrition goal for 7 days after randomization. The primary aim of this pilot trial was to achieve a 30% improvement in nutrition delivery.ResultsIn total, 125 patients were enrolled. Over the first 7 post-randomization ICU days, patients in the SPN + EN arm had a 26% increase in delivered calories and protein, whereas patients in the EN-alone arm had a 22% increase (both p < 0.001). Surgical ICU patients received poorer EN nutrition delivery and had a significantly greater increase in calorie and protein delivery when receiving SPN versus medical ICU patients. SPN proved feasible to deliver with our prescribed protocol. In this pilot trial, no significant outcome differences were observed between groups, including no difference in infection risk. Potential, although statistically insignificant, trends of reduced hospital mortality and improved discharge functional outcomes and QoL outcomes in the SPN + EN group versus the EN-alone group were observed.ConclusionsProvision of SPN + EN significantly increased calorie/protein delivery over the first week of ICU residence versus EN alone. This was achieved with no increased infection risk. Given feasibility and consistent encouraging trends in hospital mortality, QoL, and functional endpoints, a full-scale trial of SPN powered to assess these clinical outcome endpoints in high-nutritional-risk ICU patients is indicated—potentially focusing on the more poorly EN-fed surgical ICU setting.Trial registration NCT01206166 Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-017-1736-8) contains supplementary material, which is available to authorized users.

Objective-Zinc deficiency is common among populations at high risk for sepsis mortality, including elderly, alcoholic, and hospitalized patients. Zinc deficiency causes exaggerated inflammatory responses to endotoxin but has not been evaluated during bacterial sepsis. We hypothesized that subacute zinc deficiency would amplify immune responses and oxidant stress during bacterial sepsis [i.e., cecal ligation and puncture (CLP)] resulting in increased mortality and that acute nutritional repletion of zinc would be beneficial.Design-Prospective, randomized, controlled animal study. Setting-University medical center research laboratory.Subjects-Adult male C57BL/6 mice.Interventions-Ten-week-old, male, C57BL/6 mice were randomized into three dietary groups: 1) control diet, 2) zinc-deficient diet for 3 weeks, and 3) zinc-deficient diet for 3 weeks followed by oral zinc supplementation for 3 days (n = 35 per diet). Mice were then assigned to receive either CLP or sham operation (n = 15 each per diet). CLP and sham-operated treatment groups were further assigned to a 7-day survival study (n = 10 per treatment per diet) or were evaluated at 24 hours (n = 5 per treatment per diet) for signs of vital organ damage.Measurements and Main Results-Sepsis mortality was significantly increased with zinc deficiency (90% vs. 30% on control diet). Zinc-deficient animals subject to CLP had higher plasma cytokines, more severe organ injury, including increased oxidative tissue damage and cell death, particularly in the lungs and spleen. None of the sham-operated animals died or developed signs of organ damage. Zinc supplementation normalized the inflammatory response, greatly diminished tissue damage, and significantly reduced mortality.Conclusions-Subacute zinc deficiency significantly increases systemic inflammation, organ damage, and mortality in a murine polymicrobial sepsis model. Short-term zinc repletion provides significant, but incomplete protection despite normalization of inflammatory and organ damage indices.The authors have not disclosed any potential conflicts of interest. Sepsis is a major cause of morbidity, mortality, and healthcare costs in hospitalized patients and is the tenth leading cause of death overall in the United States (1). Currently, it is expected that between 20% and 50% of patients who develop sepsis will die despite receiving the current standard of appropriate therapy. The basic cellular and molecular mechanisms accounting for sepsis-related morbidity and mortality remain poorly understood. However, a number of host factors, including immunosuppression, advanced age, chronic alcoholism, and poor nutritional status, are known to increase sepsis mortality (2,3). NIH Public AccessZinc is an essential dietary micronutrient with beneficial functions that facilitate cytoprotection, improved wound healing, and tissue repair (4). Humans, in response to sepsis or endotoxin administration, experience a transient decrease in plasma zinc levels without a concomitant loss of whole body zinc content (5). ...

The alteration of zinc metabolism was more pronounced in septic patients than in noninfected critically ill patients. Specifically, sepsis was associated with lower plasma zinc concentrations and higher SLC39A8 mRNA expression, which correlated with an increased severity of illness, including cardiovascular dysfunction.

Zinc is an essential micronutrient and cytoprotectant involved in the host response to inflammatory stress. We tested whether zinc transporters, the critical regulators that maintain intracellular zinc concentrations, play a role in cell survival, particularly in lung epithelia, during inflammation. Initially, mRNA transcripts were quantitatively measured by RT-PCR for all known human zinc transporters, including 14 importers (SLC39A(1-14)) and 10 exporters (SLC30A(1-10)), in primary human lung epithelia obtained from multiple human donors and BEAS-2B cell cultures under baseline and TNF-alpha-stimulated conditions. While many zinc transporters were constitutively expressed, only SLC39A8 (Zip8) mRNA was strongly induced by TNF-alpha. Endogenous Zip8 protein was not routinely detected under baseline conditions. In sharp contrast, TNF-alpha induced the expression of a glycosylated protein that translocated to the plasma membrane and mitochondria. Increased Zip8 expression resulted in an increase in intracellular zinc content and coincided with cell survival in the presence of TNF-alpha. Inhibition of Zip8 expression using a short interfering RNA probe reduced cellular zinc content and impaired mitochondrial function in response to TNF-alpha, resulting in loss of cell viability. These data are the first to characterize human Zip8 and remarkably demonstrate that upregulation of Zip8 is sufficient to protect lung epithelia against TNF-alpha-induced cytotoxicity. We conclude that Zip8 is unique, relative to other Zip proteins, by functioning as an essential zinc importer at the onset of inflammation, thereby facilitating cytoprotection within the lung.

Zinc is an essential element that facilitates coordination of immune activation during the host response to infection. We recently reported that zinc deficiency increases systemic inflammation, vital organ damage, and mortality in a small animal model of sepsis. To investigate potential mechanisms that cause these phenomena, we used the same animal model and observed that zinc deficiency increases bacterial burden and enhances NF-kappaB activity in vital organs including the lung. We conducted further studies in the lung to determine the overall impact of zinc deficiency. At the molecular level, NF-kappaB p65 DNA-binding activity was enhanced by zinc deficiency in response to polymicrobial sepsis. Furthermore, expression of the NF-kappaB-targeted genes IL-1beta, TNFalpha, ICAM-1, and the acute phase response gene SAA1/2 were elevated by zinc deficiency. Unexpectedly, the amount of NF-kappaB p65 mRNA and protein was increased in the lung including alveolar epithelia of zinc-deficient mice. These events occurred with a significant and concomitant increase in caspase-3 activity within 24 h of sepsis onset in zinc-deficient mice relative to control group. Short-term zinc supplementation reversed these effects. Reconstitution of zinc deficiency in lung epithelial cultures resulted in similar findings in response to TNFalpha. Taken together, zinc deficiency systemically enhances the spread of infection and NF-kappaB activation in vivo in response to polymicrobial sepsis, leading to enhanced inflammation, lung injury, and, as reported previously, mortality. Zinc supplementation immediately before initiation of sepsis reversed these effects thereby supporting the plausibility of future studies that explore zinc supplementation strategies to prevent sepsis-mediated morbidity and mortality.

Rationale: Monocytes are central to the initiation of the inflammatory response in sepsis, with caspase-1 activation playing a key role. Monocyte deactivation during sepsis has been linked to poor outcomes. Objectives: Given the importance of caspase-1 in the immune response, we investigated whether monocytes from patients early in septic shock demonstrate alterations in mRNAs for caspase-1-related molecules. Methods: Patients with septic shock (n 5 26; age .18 years), critically ill intensive care unit patients (n 5 20), and healthy volunteers (n 5 22) were enrolled in a prospective cohort study in a university intensive care unit. Demographic, biological, physiologic, and plasma cytokine measurements were obtained. Monocytes were assayed for ex vivo tumor necrosis factor-a production, and fresh monocyte mRNA was analyzed by quantitative reverse-transcription polymerase chain reaction for Toll-like receptors, NOD-LRR proteins, cytokines, and nuclear factor-kB-related genes. Measurements and Main Results: Relative copy numbers for the inflammasome mRNAs for ASC, caspase-1, NALP1, and Pypaf-7 were significantly lower in patients with septic shock compared with critically ill control subjects. NALP1 mRNA levels were linked to survival in patients with sepsis (P 5 0.0068) and correlated with SAPS II scores (r 5 20.63). Conclusions: These data suggest that monocyte deactivation occurs during the earliest stages of the systemic inflammatory response and that changes in inflammasome mRNA expression are part of this process.

ObjectiveImmune dysregulation during sepsis is poorly understood, however, lymphocyte apoptosis has been shown to correlate with poor outcomes in septic patients. The inflammasome, a molecular complex which includes caspase-1, is essential to the innate immune response to infection and also important in sepsis induced apoptosis. Our group has recently demonstrated that endotoxin-stimulated monocytes release microvesicles (MVs) containing caspase-1 that are capable of inducing apoptosis. We sought to determine if MVs containing caspase-1 are being released into the blood during human sepsis and induce apoptosis..DesignSingle-center cohort studyMeasurements50 critically ill patients were screened within 24 hours of admission to the intensive care unit and classified as either a septic or a critically ill control. Circulatory MVs were isolated and analyzed for the presence of caspase-1 and the ability to induce lymphocyte apoptosis. Patients remaining in the ICU for 48 hours had repeated measurement of caspase-1 activity on ICU day 3.Main ResultsSeptic patients had higher microvesicular caspase-1 activity 0.05 (0.04, 0.07) AFU versus 0.0 AFU (0, 0.02) (p<0.001) on day 1 and this persisted on day 3, 0.12 (0.1, 0.2) versus 0.02 (0, 0.1) (p<0.001). MVs isolated from septic patients on day 1 were able to induce apoptosis in healthy donor lymphocytes compared with critically ill control patients (17.8±9.2% versus 4.3±2.6% apoptotic cells, p<0.001) and depletion of MVs greatly diminished this apoptotic signal. Inhibition of caspase-1 or the disruption of MV integrity abolished the ability to induce apoptosis.ConclusionThese findings suggest that microvesicular caspase-1 is important in the host response to sepsis, at least in part, via its ability to induce lymphocyte apoptosis. The ability of microvesicles to induce apoptosis requires active caspase-1 and intact microvesicles.

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