Cholesterol and its association with muscle weakness in critical illness

Controversy exists about the timing of the initiation of parenteral nutrition in critically ill adults in whom caloric targets cannot be met by enteral nutrition alone. In this randomized, multicenter trial, we compared early initiation of parenteral nutrition (European guidelines) with late initiation (American and Canadian guidelines) in adults in the intensive care unit (ICU) to supplement insufficient enteral nutrition. In 2312 patients, parenteral nutrition was initiated within 48 hours after ICU admission (early-initiation group), whereas in 2328 patients, parenteral nutrition was not initiated before day 8 (late-initiation group). A protocol for the early initiation of enteral nutrition was applied to both groups, and insulin was infused to achieve normoglycemia. Patients in the late-initiation group had a relative increase of 6.3% in the likelihood of being discharged alive earlier from the ICU (hazard ratio, 1.06; 95% confidence interval [CI], 1.00 to 1.13; P=0.04) and from the hospital (hazard ratio, 1.06; 95% CI, 1.00 to 1.13; P=0.04), without evidence of decreased functional status at hospital discharge. Rates of death in the ICU and in the hospital and rates of survival at 90 days were similar in the two groups. Patients in the late-initiation group, as compared with the early-initiation group, had fewer ICU infections (22.8% vs. 26.2%, P=0.008) and a lower incidence of cholestasis (P<0.001). The late-initiation group had a relative reduction of 9.7% in the proportion of patients requiring more than 2 days of mechanical ventilation (P=0.006), a median reduction of 3 days in the duration of renal-replacement therapy (P=0.008), and a mean reduction in health care costs of €1,110 (about $1,600) (P=0.04). Late initiation of parenteral nutrition was associated with faster recovery and fewer complications, as compared with early initiation. (Funded by the Methusalem program of the Flemish government and others; EPaNIC ClinicalTrials.gov number, NCT00512122.).

To assess the initial serum levels of lipids and lipoproteins and their correlations with the clinical outcome for patients with severe sepsis. The ability of high-density lipoprotein (HDL) to attenuate lipopolysaccharide (LPS)-induced cytokine production was also examined in vitro. Prospective, observational cohort study. Medical intensive care unit (ICU) of a tertiary-level university hospital. Sixty-three consecutive patients with severe sepsis. Blood samples were drawn within the first day of severe sepsis and the subsequent 14 days. Clinical outcome, including length of ICU stay, infection subsequent to hospital stay, and death, were monitored prospectively. Compared with the survivors, patients who died within 30 days had significantly lower levels of HDL cholesterol and apolipoprotein A-I during the first 4 days of severe sepsis. On day 1, HDL cholesterol levels correlated inversely with interleukin-6 (r = -0.72; p 7 days) and the hospital-acquired infection rate were increased among patients with day 1 levels of HDL cholesterol of <20 mg/dL and apolipoprotein A-I of <100 mg/dL. Multivariate analysis identified an HDL cholesterol level of <20 mg/dL on day 1 (odds ratio, 12.92; 95% confidence interval, 2.73-61.29) and Acute Physiology and Chronic Health Evaluation II score (odds ratio, 1.15; 95% confidence interval, 1.04-1.26) as independent predictors of the overall 30-day mortality rate. In human macrophages, LPS-induced TNF-alpha release was attenuated by incremental doses of HDL cholesterol added simultaneously (p < .01). However, HDL failed to suppress LPS-induced TNF-alpha production when administered after macrophages were exposed to LPS. A low HDL cholesterol level on day 1 of severe sepsis is significantly associated with an increase in mortality and adverse clinical outcomes. In cultured macrophages, HDL can attenuate LPS-induced TNF-alpha production only if added concomitantly with, but not after, LPS exposure.

Lipoproteins have been implicated to play a role in innate immunity. Changes in lipoprotein levels have been reported in a variety of inflammatory disorders. Not much is known about lipoprotein metabolism in patients with severe sepsis. We conducted an ancillary study in a multiple-center phase III sepsis trial to investigate the dynamics of plasma lipoproteins in patients with severe sepsis. Prospective analysis in patients meeting criteria for severe sepsis as part of a multiple-center sepsis study (KyberSept) with antithrombin III (Kybernin P). University hospital intensive care unit. Seventeen patients were included in the study. Randomized patients received a loading dose of 6000 IU of antithrombin III (Kybernin P) or placebo followed by a 96-hr continuous infusion of 250 IU/hr antithrombin III (Kybernin P) or placebo. In each patient, serial blood samples for total cholesterol, lipoprotein cholesterol, triglycerides, apolipoprotein A-1, apolipoprotein B, and C-reactive protein determination as well as clinical data were collected over 28 days. Plasma cholesterol levels rapidly decreased from 2.67 +/- 2.02 mmol/L on day 0 to a nadir of 1.41 +/- 0.70 mmol/L on day 3, followed by a slow increase to 4.18 +/- 1.94 mmol/L on day 28. High-density lipoprotein (HDL) cholesterol concentrations decreased rapidly from 0.84 +/- 0.92 mmol/L to a nadir of 0.42 +/- 0.35 mmol/L on day 3, to show a slow increase during the following 4 wks to 0.84 +/- 0.42 mmol/L. The low-density lipoprotein (LDL) cholesterol concentrations were already low (0.94 +/- 0.81 mmol/L) at study entry, to show a progressive increase to subnormal values (2.01 +/- 0.94 mmol/L) at 4 wks. Nadir and recovery lipoprotein concentrations were significantly different (paired Student's t-test, p <.05). A significant correlation was found between HDL cholesterol and apolipoprotein A-1 (r =.714, p <.05) and between LDL cholesterol and apolipoprotein B (r =.733, p <.05). There was no statistical difference in lipoprotein concentrations either between survivors and nonsurvivors or between patients receiving antithrombin III or placebo. Serum amyloid A was a major apoprotein (45%) in HDL at the start of the sepsis and was slowly replaced by apolipoprotein A-1 during recovery. A positive correlation was found between plasma C-reactive protein concentrations and serum amyloid A concentrations in HDL (r =.684, p <.05). No other relevant correlations were found between inflammatory and lipoprotein parameters. In patients with severe sepsis, lipoprotein concentrations rapidly change and can be reduced to 50% of recovery concentrations. The pattern of early rapid decline is found primarily in the HDL and a slow recovery in both HDL and LDL fractions. The correlation between apolipoprotein and lipoprotein cholesterol concentrations suggests a decline in lipoprotein particles. During severe sepsis, HDL is shifted to acute phase HDL, which is enriched in serum amyloid A and depleted of cholesterol and apolipoprotein A-1. Lipoprotein concentrations are unable to discriminate between survivors and nonsurvivors.