Utilization of Immediate Energy Resources in Critical Care, Emphasis on Phosphocreatine

Abstract

Modern societies heavily rely on sophisticated energy resources, likewise human baseline daily and stress related activity commencing on the molecular and cellular level is essentially dependent on properly functioning energy producing, rebooting and storage conditions.
Adenosine triphosphate (ATP) assumes the role of universal energy currency stored in high energy phosphate bounds, with immediate availability for biochemical processes requiring fuel resources. The intrinsic resources for ATP are mitochondria providing synthesis from ADP mediated by ATPase, and ATP is recycled in significant amounts from high ATP containing organs, like muscles. ICU patients are characterized by low ATP reserves. The reasons are conceivably multifactorial, including increased requirements, mitochondrial damage, catabolism and muscle breakdown, leading to impaired availability and increased demand.
Phosphocreatine (PCr) provides the high energy substrate to promote regeneration of ATP rendering an immediate energy resource bypassing the largely oxygen dependent oxidative phosphorylation. Currently, phosphocreatine substitution is available therapeutically, offering a transient supportive tool to the organism during conditions when demand is enhanced, production may suffer and endogenous resources of creatine or phosphocreatine are relatively low.
Exogenous phosphocreatine supplementation may be beneficial during critical care illness, when energy resource processing and utilization may be dampened by ischemic and inflammatory pathological processes. The significance of supplementary immediate energy substitution is demonstrated on case reports during inflammatory conditions.