RESUMEN
OBJECTIVES: The aim of this study was to contribute to the design of specialized parenteral nutrition protocols in surgery by evaluating the dynamics of polyunsaturated fatty acid (PUFA) concentrations in different body pools after the infusion of fish oil-containing lipid emulsion (FOLE) in rats that had undergone surgical central venous catheterization (CVC). METHODS: After 5-d adaptation in metabolic cages, 78 male Lewis rats (300-450 g) fed a standard diet were sacrificed (baseline control) or had only CVC (surgical control) or also received a 72-h infusion of a parenteral lipid emulsion with or without fish oil. The catheterized animals were sacrificed 0 (T0), 2 (T2), 6 (T6), and 12 h (T12) after the infusion ended. Gas chromatography was used to determine the concentrations of eicosapentaenoic (EPA), docosahexaenoic (DHA), and arachidonic (ARA) acids and the ω-3 to ω-6 ratio in plasma, liver, and blood leukocytes. Kruskal-Wallis and Wilcoxon tests were applied to plasma and liver data and descriptive analysis to leukocyte data. RESULTS: Plasma, liver, and leukocytes exhibited almost undetectable EPA and DHA and detectable ARA concentrations at baseline. Immediately after FOLE infusion (T0), these PUFAs changed in all pools, resulting in a higher ratio of ω-3 to ω-6 compared with rats with no FOLE infusion (P < 0.05). All these changes decreased over time, with residual effects remaining until T6 in plasma, T12 in liver, and only until T2 in leukocytes. CONCLUSION: Data from this study suggest that ω-3 PUFAs are cleared early after the end of FOLE infusion, mainly in leukocytes. This should be considered when FOLEs are applied for immunomodulatory purposes in surgery.
Asunto(s)
Ácidos Grasos Omega-3 , Aceites de Pescado , Animales , Ácidos Docosahexaenoicos , Ácido Eicosapentaenoico , Emulsiones Grasas Intravenosas , Masculino , Nutrición Parenteral , Ratas , Ratas Endogámicas LewRESUMEN
Intravenous lipid emulsions (ILEs) have been an integral component of parenteral nutrition for more than 50 years. Numerous formulations are available and are based on vegetable (soybean, olive, coconut) and animal (fish) oils. Therefore, each of these formulations has a unique fatty acid composition that offers both benefits and limitations. As clinical experience and our understanding of the effects of fatty acids on various physiological processes has grown, there is evidence to suggest that some ILEs may have benefits compared with others. Current evidence suggests that olive oil-based ILE may preserve immune, hepatobiliary, and endothelial cell function, and may reduce lipid peroxidation and plasma lipid levels. There is good evidence from a large randomized controlled study to support a benefit of olive oil-based ILE over soybean oil-based ILE on reducing infections in critically ill patients. At present there is limited evidence to demonstrate a benefit of olive oil-based ILE over other ILEs on glucose metabolism, and few data exist to demonstrate a benefit on clinical outcomes such as hospital or intensive care unit stay, duration of mechanical ventilation, or mortality. We review the current research and clinical evidence supporting the potential positive biological and clinical aspects of olive oil-based ILE and conclude that olive oil-based ILE is well tolerated and provides effective nutritional support to various PN-requiring patient populations. Olive oil-based ILE appears to support the innate immune system, is associated with fewer infections, induces less lipid peroxidation, and is not associated with increased hepatobiliary or lipid disturbances. These data would suggest that olive oil-based ILE is a valuable option in various PN-requiring patient populations.
Asunto(s)
Emulsiones Grasas Intravenosas/química , Aceite de Oliva/química , Nutrición Parenteral , Biomarcadores , Emulsiones Grasas Intravenosas/efectos adversos , Humanos , Peroxidación de Lípido/efectos de los fármacos , Lípidos/sangre , Aceite de Oliva/efectos adversosRESUMEN
Although there has been great interest in the effects of amino acids on immune function, little is known about the impact of changes in BCAA availability on the ability of the immune system to function. Human immune cells incorporate BCAA into proteins and are able to oxidize BCAA. The immune system exists to protect the host from pathogenic invaders and from other noxious insults. Upon infection, there is a marked increase in demand for substrates by the immune system; these substrates provide energy and are the precursors for the synthesis of new cells, effector molecules, and protective molecules. Cell culture studies show that BCAA are absolutely essential for lymphocytes to synthesize protein, RNA, and DNA and to divide in response to stimulation. In mice, dietary BCAA restriction impairs several aspects of the immune function and increases the susceptibility to pathogens. Postsurgical or septic patients given BCAA intravenously showed improved immunity and this may relate to improved outcome. BCAAs are therefore absolutely essential for lymphocyte responsiveness and are necessary to support other immune cell functions. However, many aspects of BCAA and its effects on immune function have been understudied or not studied at all. More research is needed to understand the extent of the immune system's requirement for BCAA. It is likely that the essentiality of BCAA for the function of immune cells relates to protein synthesis.