Impact of Early Parenteral Nutrition on Muscle and Adipose Tissue Compartments During Critical Illness*

Abstract

Introduction Autophagy is well known as one of the biogenic responses against various stresses, which possesses the benefi cial roles for survival, but little is known about the dynamics and its signifi cance during the septic condition. We hypothesized that autophagy is induced during the septic condition, and contributes to protect from tissue damage which subsequently leads to organ dysfunction. We confi rm whether the autophagic process is accelerated or sustained in an acute phase of sepsis and we also determine its physiological role. Methods Sepsis was induced by cecal ligation and puncture (CLP) in mice. We examined the kinetics of autophagosome and auto lysosome formation which may explain the status of autophagy by western blotting, immunohistochemistry, and electron microscopy. To investigate a precise role of autophagy in CLP-induced sepsis, chloroquine, an autophagy inhibitor, was administered to the CLP-operated mice, and blood chemistry, pathology of the liver and survival were evaluated. Results Autophagy demonstrated by the ratio of LC3-II/LC3-I was induced over the time course up to 24 hours after CLP. The ratio was particularly increased in the liver, heart and spleen. Autophagosome formation became maximal at 6 hours and declined by 24 hours after CLP. Autolysosome formation as evaluated by both fusion of GFP-LC3 dots with LAMP1 immunohistochemistry and electron microscopy was also increased after the procedure. Furthermore, inhibition of autophagy by chloroquine during the CLP procedure resulted in elevation of serum AST levels, and signifi cantly increased mortality in mice. Conclusion Autophagy was induced in several organs over the time course of the CLP sepsis model and then the process was gradually completed to degradation of the components. Our data suggest autophagy plays a protective role in organ dysfunction in sepsis. P2Reversible depressive eff ect of TNFα on a model of isolated perfused rat heart BV Nguyen Introduction Acute myocardial depression in septic shock is common [1]. Myocardial depression is mediated by circulating depressant substances, which until now have been incompletely characterized [2].The aim of our study was to observe the eff ects of TNFα on the model of perfused rat heart. Methods After profound anesthesia with pentothal, the Wistar rats were killed by exsanguination. After sternotomy, the heart was taken and connected to the Langendorf column. The apex of the heart was hooked to a strength sensor. Biopac student laboratory software was used to record and analyse heart contractions. Contractions were recorded every 5 minutes during periods of 20 minutes. Control measurements were fi rst recorded. We measured four parameters: heart rate, contraction force, speeds of contraction and relaxation for control, during TNFα (20 ng/ml) exposure and after removal of TNFα. We express the variations of parameters as percentage of the control ± SEM. A paired t test was used to compare heart rate, contraction amplitude, speeds of contraction and relaxation with TNFα and ...

Timing and Indication for Parenteral Nutrition in the Critically Ill

“…These analyses revealed a pronounced reduction in femoral muscle mass. Regardless of the randomization group, about 7 % of the femoral muscle mass was lost [ 74 ]. Early PN was not only unable to attenuate muscle wasting, it also induced lipogenesis refl ected by increased intramuscular fat areas and loss of muscle attenuation.…”

“…The EPaNIC study protocol included a detailed analysis of macroscopic [ 74 ], microscopic and molecular changes within the muscle in patients randomized to early versus late PN [ 31 ]. In addition, analysis of the cumulative nitrogen balances allowed to gain more insight in the metabolic fate of infused amino acids.…”

Nutrition in the ICU: It’s Whey Cool

“…EPaNIC was a large randomized controlled study that compared the early initiation of TPN (early TPN group) when enteral nutrition was insuffi cient with delayed parenteral nutrition which was initiated after 7 days, allowing a pronounced nutritional defi cit to occur in the late TPN group [ 4 ]. Casaer et al evaluated the impact of early TPN on muscle and adipose tissue compartments in a subgroup of patients enrolled in the EPaNIC study [ 32 ]. Over the fi rst week there was a 6.9 % loss of femoral muscle volume in both groups.…”

Muscle Injury During Critical Illness

“…Increased proteolysis relative to either suppressed, normal, or elevated protein synthesis is essential to the development of muscle atrophy. 12 Recent clinical studies evaluating the effect of total parenteral nutrition on muscle compartments 13 and full enteral feedings compared with trophic feedings in patients with lung injury 14 did not show improvement in muscle mass or functional outcome with feeding. These clinical observations are entirely consistent with the mechanistic data presented by Puthucheary and colleagues 11 and suggest that incurred muscle injury and enhanced proteolysis is independent of adequate nutrition in the early stages of critical illness.…”