Glucose-6-phosphate dehydrogenase-derived NADPH fuels superoxide production in the failing heart.

In the failing heart, NADPH oxidase and uncoupled NO synthase utilize cytosolic NADPH to form superoxide. NADPH is supplied principally by the pentose phosphate pathway, whose rate-limiting enzyme is glucose 6-phosphate dehydrogenase (G6PD). Therefore, we hypothesized that cardiac G6PD activation drives part of the excessive superoxide production implicated in the pathogenesis of heart failure. Pacing-induced heart failure was performed in eight chronically instrumented dogs. Seven normal dogs served as control. End-stage failure occurred after 28 +/- 1 days of pacing, when left ventricular end-diastolic pressure reached 25 mm Hg. In left ventricular tissue homogenates, spontaneous superoxide generation measured by lucigenin (5 microM) chemiluminescence was markedly increased in heart failure (1338 +/- 419 vs. 419 +/- 102 AU/mg protein, P < 0.05), as were NADPH levels (15.4 +/- 1.5 vs. 7.5 +/- 1.5 micromol/gww, P < 0.05). Superoxide production was further stimulated by the addition of NADPH. The NADPH oxidase inhibitor gp91(ds-tat) (50 microM) and the NO synthase inhibitor L-NAME (1 mM) both significantly lowered superoxide generation in failing heart homogenates by 80% and 76%, respectively. G6PD was upregulated and its activity higher in heart failure compared to control (0.61 +/- 0.10 vs. 0.24 +/- 0.03 nmol/min/mg protein, P < 0.05), while superoxide production decreased to normal levels in the presence of the G6PD inhibitor 6-aminonicotinamide. We conclude that the activation of myocardial G6PD is a novel mechanism that enhances NADPH availability and fuels superoxide-generating enzymes in heart failure

Non-invAsive VentIlation for early General wArd respiraTory failurE (NAVIGATE):A multicenter randomized controlled study. Protocol and statistical analysis plan

Few randomized trials have evaluated the use of non-invasive ventilation (NIV) for early acute respiratory failure (ARF) in non-intensive care unit (ICU) wards. The aim of this study is to test the hypothesis that early NIV for mild-moderate ARF in non-ICU wards can prevent development of severe ARF

Angiotensin II for the Treatment of Vasodilatory Shock

BACKGROUND Vasodilatory shock that does not respond to high-dose vasopressors is associated with high mortality. We investigated the effectiveness of angiotensin II for the treatment of patients with this condition. METHODS We randomly assigned patients with vasodilatory shock who were receiving more than 0.2 mu g of norepinephrine per kilogram of body weight per minute or the equivalent dose of another vasopressor to receive infusions of either angiotensin II or placebo. The primary end point was a response with respect to mean arterial pressure at hour 3 after the start of infusion, with response defined as an increase from baseline of at least 10 mm Hg or an increase to at least 75 mm Hg, without an increase in the dose of background vasopressors. RESULTS A total of 344 patients were assigned to one of the two regimens; 321 received a study intervention (163 received angiotensin II, and 158 received placebo) and were included in the analysis. The primary end point was reached by more patients in the angiotensin II group (114 of 163 patients, 69.9%) than in the placebo group (37 of 158 patients, 23.4%) (odds ratio, 7.95; 95% confidence interval [CI], 4.76 to 13.3; P<0.001). At 48 hours, the mean improvement in the cardiovascular Sequential Organ Failure Assessment (SOFA) score (scores range from 0 to 4, with higher scores indicating more severe dysfunction) was greater in the angiotensin II group than in the placebo group (-1.75 vs. -1.28, P = 0.01). Serious adverse events were reported in 60.7% of the patients in the angiotensin II group and in 67.1% in the placebo group. Death by day 28 occurred in 75 of 163 patients (46%) in the angiotensin II group and in 85 of 158 patients (54%) in the placebo group (hazard ratio, 0.78; 95% CI, 0.57 to 1.07; P = 0.12). CONCLUSIONS Angiotensin II effectively increased blood pressure in patients with vasodilatory shock that did not respond to high doses of conventional vasopressors. (Funded by La Jolla Pharmaceutical Company; ATHOS-3 ClinicalTrials.gov number, NCT02338843.)Peer reviewe

Differential clinical characteristics, management and outcome of delirium among ward compared with intensive care unit patients

BACKGROUND: Delirium is common in hospitalised patients but its epidemiology remains poorly characterised. AIMS: To test the hypothesis that patient demographics, clinical phenotype, management and outcomes of patient with delirium in hospital ward patients differ from intensive care unit (ICU) patients. METHODS: Retrospective cohort of patients admitted to an Australian university-affiliated hospital between March 2013 and April 2017 and coded for delirium at discharge using the International Classification of Diseases System, 10th revision, criteria. RESULTS: Among 61 032 hospitalised patients, 2864 (4.7%) were coded for delirium. From these, we studied a random sample of 100 ward patients and 100 ICU patients. Ward patients were older (median age: 84 vs 65 years; P < 0.0001), more likely to have dementia (38% vs 2% for ICU patients; P < 0.0001) and less likely to have had surgery (24% vs 62%; P < 0.0001). Of ward patients, 74% had hypoactive delirium, while 64% of ICU patients had agitated delirium (P < 0.0001). Persistent delirium at hospital discharge was more common among ward patients (66% vs 17%, P < 0.0001). On multivariable analysis, age and dementia predicted persistent delirium, while surgery predicted recovery. CONCLUSIONS: Delirium in ward patients is profoundly different from delirium in ICU patients. It has a dominant hypoactive clinical phenotype, is preceded by dementia and is less likely to recover at hospital discharge. Therefore, delirium prevention, detection and goals of care should be adapted to the environment in which it occurs

Differential clinical characteristics, management and outcome of delirium among ward compared with intensive care unit patients

BACKGROUND: Delirium is common in hospitalised patients but its epidemiology remains poorly characterised. AIMS: To test the hypothesis that patient demographics, clinical phenotype, management and outcomes of patient with delirium in hospital ward patients differ from intensive care unit (ICU) patients. METHODS: Retrospective cohort of patients admitted to an Australian university-affiliated hospital between March 2013 and April 2017 and coded for delirium at discharge using the International Classification of Diseases System, 10th revision, criteria. RESULTS: Among 61 032 hospitalised patients, 2864 (4.7%) were coded for delirium. From these, we studied a random sample of 100 ward patients and 100 ICU patients. Ward patients were older (median age: 84 vs 65 years; P < 0.0001), more likely to have dementia (38% vs 2% for ICU patients; P < 0.0001) and less likely to have had surgery (24% vs 62%; P < 0.0001). Of ward patients, 74% had hypoactive delirium, while 64% of ICU patients had agitated delirium (P < 0.0001). Persistent delirium at hospital discharge was more common among ward patients (66% vs 17%, P < 0.0001). On multivariable analysis, age and dementia predicted persistent delirium, while surgery predicted recovery. CONCLUSIONS: Delirium in ward patients is profoundly different from delirium in ICU patients. It has a dominant hypoactive clinical phenotype, is preceded by dementia and is less likely to recover at hospital discharge. Therefore, delirium prevention, detection and goals of care should be adapted to the environment in which it occurs

How a positive fluid balance develops in acute kidney injury: A binational, observational study

Purpose: A positive fluid balance (FB) is associated with harm in intensive care unit (ICU) patients with acute kidney injury (AKI). We aimed to understand how a positive balance develops in such patients. Methods: Multinational, retrospective cohort study of critically ill patients with AKI not requiring renal replacement therapy. Results: AKI occurred at a median of two days after admission in 7894 (17.3%) patients. Cumulative FB became progressively positive, peaking on day three despite only 848 (10.7%) patients receiving fluid resuscitation in the ICU. In those three days, persistent crystalloid use (median:60.0 mL/h; IQR 28.9–89.2), nutritional intake (median:18.2 mL/h; IQR 0.0–45.9) and limited urine output (UO) (median:70.8 mL/h; IQR 49.0–96.7) contributed to a positive FB. Although UO increased each day, it failed to match input, with only 797 (10.1%) patients receiving diuretics in ICU. After adjustment, a positive FB four days after AKI diagnosis was associated with an increased risk of hospital mortality (OR 1.12;95% confidence intervals 1.05–1.19;p-value Conclusion: Among ICU patients with AKI, cumulative FB increased after diagnosis and was associated with an increased risk of mortality. Continued crystalloid administration, increased nutritional intake, limited UO, and minimal use of diuretics all contributed to positive FB. Key points: Question How does a positive fluid balance develop in critically ill patients with acute kidney injury? Findings Cumulative FB increased after AKI diagnosis and was secondary to persistent crystalloid fluid administration, increasing nutritional fluid intake, and insufficient urine output. Despite the absence of resuscitation fluid and an increasing cumulative FB, there was persistently low diuretics use, ongoing crystalloid use, and a progressive escalation of nutritional fluid therapy. Meaning Current management results in fluid accumulation after diagnosis of AKI, as a result of ongoing crystalloid administration, increasing nutritional fluid, limited urine output and minimal diuretic use.</p

Chronic activation of peroxisome proliferator-activated receptor-alpha with fenofibrate prevents alterations in cardiac metabolic phenotype without changing the onset of decompensation in pacing-induced heart failure.

Severe heart failure (HF) is characterized by profound alterations in cardiac metabolic phenotype, with down-regulation of the free fatty acid (FFA) oxidative pathway and marked increase in glucose oxidation. We tested whether fenofibrate, a pharmacological agonist of peroxisome proliferator-activated receptor-alpha, the nuclear receptor that activates the expression of enzymes involved in FFA oxidation, can prevent metabolic alterations and modify the progression of HF. We administered 6.5 mg/kg/day p.o. fenofibrate to eight chronically instrumented dogs over the entire period of high-frequency left ventricular pacing (HF + Feno). Eight additional HF dogs were not treated, and eight normal dogs were used as a control. [3H]Oleate and [14C]Glucose were infused intravenously to measure the rate of substrate oxidation. At 21 days of pacing, left ventricular end-diastolic pressure was significantly lower in HF + Feno (14.1 +/- 1.6 mm Hg) compared with HF (18.7 +/- 1.3 mm Hg), but it increased up to 25 +/- 2 mm Hg, indicating end-stage failure, in both groups after 29 +/- 2 days of pacing. FFA oxidation was reduced by 40%, and glucose oxidation was increased by 150% in HF compared with control, changes that were prevented by fenofibrate. Consistently, the activity of myocardial medium chain acyl-CoA dehydrogenase, a marker enzyme of the FFA beta-oxidation pathway, was reduced in HF versus control (1.46 +/- 0.25 versus 2.42 +/- 0.24 micromol/min/gram wet weight (gww); p < 0.05) but not in HF + Feno (1.85 +/- 0.18 micromol/min/gww; N.S. versus control). Thus, preventing changes in myocardial substrate metabolism in the failing heart causes a modest improvement of cardiac function during the progression of the disease, with no effects on the onset of decompensation

Altered cardiac metabolic phenotype after prolonged inhibition of NO synthesis in chronically instrumented dogs.

Acute inhibition of nitric oxide (NO) synthase causes a reversible alteration in myocardial substrate metabolism. We tested the hypothesis that prolonged NO synthase inhibition alters cardiac metabolic phenotype. Seven chronically instrumented dogs were treated with N(omega)-nitro-L-arginine methyl ester (L-NAME, 35 mg.kg(-1).day(-1) po) for 10 days to inhibit NO synthesis, and seven were used as controls. Cardiac free fatty acid, glucose, and lactate oxidation were measured by infusion of [(3)H]oleate, [(14)C]glucose, and [(13)C]lactate, respectively. After 10 days of L-NAME administration, despite no differences in left ventricular afterload, cardiac O(2) consumption was significantly increased by 30%, consistent with a marked enhancement in baseline oxidation of glucose (6.9 +/- 2.0 vs. 1.7 +/- 0.5 micromol.min(-1).100 g(-1), P < 0.05 vs. control) and lactate (21.6 +/- 5.6 vs. 11.8 +/- 2.6 micromol.min(-1).100 g(-1), P < 0.05 vs. control). When left ventricular afterload was increased by ANG II infusion to stimulate myocardial metabolism, glucose oxidation was augmented further in the L-NAME than in the control group, whereas free fatty acid oxidation decreased. Exogenous NO (diethylamine nonoate, 0.01 micromol.kg(-1).min(-1) iv) could not reverse this metabolic alteration. Consistent with the accelerated rate of carbohydrate oxidation, total myocardial pyruvate dehydrogenase activity and protein expression were higher (38 and 34%, respectively) in the L-NAME than in the control group. Also, protein expression of the constitutively active glucose transporter GLUT-1 was significantly elevated (46%) vs. control. We conclude that prolonged NO deficiency causes a profound alteration in cardiac metabolic phenotype, characterized by selective potentiation of carbohydrate oxidation, that cannot be reversed by a short-term infusion of exogenous NO. This phenomenon may constitute an adaptive mechanism to counterbalance cardiac mechanical inefficiency