tailieunhanh - Báo cáo y học: "Cerebral net exchange of large neutral amino acids after lipopolysaccharide infusion in healthy humans"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Cerebral net exchange of large neutral amino acids after lipopolysaccharide infusion in healthy humans. | Berg et al. Critical Care 2010 14 R16 http content 14 1 R16 c CRITICAL CARE RESEARCH Open Access Cerebral net exchange of large neutral amino acids after lipopolysaccharide infusion in healthy humans Ronan MG Berg1 Sarah Taudorf1 Damian M Bailey2 Carsten Lundby3 Fin Stolze Larsen4 Bente Klarlund Pedersen1 3 Kirsten M0ller1 5 Abstract Introduction Alterations in circulating large neutral amino acids LNAAs leading to a decrease in the plasma ratio between branched-chain and aromatic amino acids BCAA AAA ratio may be involved in sepsis-associated encephalopathy. We hypothesised that a decrease in the BCAA AAA ratio occurs along with a net cerebral influx of the neurotoxic AAA phenylalanine in a human experimental model of systemic inflammation. Methods The BCAA AAA ratio the cerebral delivery and net exchange of LNAAs and ammonia were measured before and 1 hour after a 4-hour intravenous infusion of Escherichia coli lipopolysaccharide LPS in 12 healthy young men. Results LPS induced systemic inflammation reduced the BCAA AAA ratio increased the cerebral delivery and unidirectional influx of phenylalanine and abolished the net cerebral influx of the BCAAs leucine and isoleucine. Furthermore a net cerebral efflux of glutamine which was independent of the cerebral net exchange of ammonia was present after LPS infusion. Conclusions Systemic inflammation may affect brain function by reducing the BCAA AAA ratio thereby changing the cerebral net exchange of LNAAs. Introduction Sepsis-associated encephalopathy SAE is often one of the first manifestations of sepsis 1 and is associated with an adverse outcome 2 3 . The pathogenesis of SAE is largely unknown although several potential mechanisms have been investigated including cerebral blood flow CBF and metabolic alterations intracranial hypertension cerebral edema disruption of the blood-brain barrier BBB neuronal degeneration and abnormal neurotransmitter composition 4 . Sepsis is characterized by increased .