Ion Gradients And Metabolic Energy In Animal Tissue

摘要：工作灌注心脏中9种主要无机离子的梯度能量、胞外相和胞内相电位以及ATP水解的δ G接近平衡[Masuda et al ., J Biol Chem 1990; 65:20321-34]。乙醇代谢可使肝细胞静息电位从-28 mV升高至-40 mV [Veech， et al ., 1994,18:10 - 10]。先前有研究表明，仅改变可用底物就能改变心脏ATP水解的δ G，使心脏的水力工作效率提高28% [Kashiwaya et al ., Am J Cardiol 1997;80:50 -64]。由于任何类型的损伤都会引起细胞离子分布的刻板变化，其中细胞获得Na+，失去K+并膨胀，因此损伤的这些刻板变化可能通过简单地改变给予损伤或烧伤受害者的液体成分来逆转。我们进一步证明，细胞内相和细胞外相之间所有9种常见无机离子的梯度形成了一个Donnan接近平衡系统，该系统将相之间的电位与ATP水解能量联系起来[Veech RL等，IUBMB Life 2002; 54:21 1-52]。由于这些研究和我们早期的研究批评了现有的肠外液体的组成[Veech RL， Am J clinin nur 1986；[44:51 . 19]由医学学院召集的一个小组建议开始对制造新的复苏液体的可行性进行调查[《液体复苏》，国家科学院出版社，华盛顿特区，1999年]。

Summary: The energy of the gradients of the nine major inorganic ions in working perfused heart are in near equilibrium with each other, the electrical potential between extra- and intracellular phase and the delta G of ATP hydrolysis [Masuda T et al, J Biol Chem 1990;265:20321-34]. The metabolism of ethanol increases the resting electrical potential of hepatocytes from -28 to -40 mV [Veech RL et al, Alch Clin Exp Res 1994;18:1040-56]. Previously, we showed that merely changing the substrate available altered the delta G of ATP hydrolysis in heart and improved the efficiency of hydraulic work of heart by 28% [Kashiwaya Y et al, Am J Cardiol 1997;80:50A-64A]. Since injuries of any sort induce a stereotypic change in cellular ionic distributions wherein the cell gains Na+, loses K+ and swells, these stereotypic changes of injury can possibly be reversed by simple changes in the compositions of fluids administered to victims of injury or burns. We went on to show that the gradients of all nine common inorganic ions between intra and extracellular phases of a cell form a Donnan near equilibrium system relating the electrical potential between the phases to the energy of ATP hydrolysis [Veech RL et al, IUBMB Life 2002;54:241-52]. As a result of these studies and our earlier studies criticizing the composition of existing parenteral fluids [Veech RL, Am J Clin Nutr 1986;44:519-51] a panel convened by the Academy of Medicine, recommended that investigation of the feasibility of making new resuscitation fluids be initiated [Fluid Resuscitation, Natl Acad Press, Wash DC, 1999]. We have taken part in these studies sponsored by the Department of Defense since that time. The goal is to improve the standard treatment of hemorrhage and burns, which has not changed over the past 50 years. We had earlier shown that the d isomer of lactic acid, a component in Ringers Lactate, induced cardiac arrythmias in children undergoing resuscitation from burn and could induce fatal arrythmias in experimental animals [Chan L et al, Physiol Behav Sci 1994;29:383-94]. In collaboration with the Naval Blood Research Laboratory, we designed and caused to be manufactured alternatives Ringer's solutions for use in resuscitation from hemorrhage in experimental animals. Tests of these newly manufactured fluids performed at USUHS have shown that resuscitation from hemorrhage with the standard high volume Ringer's lactate protocol leads to apoptosis in the lung 24 hours after hemorrhage and that this untoward effect can be avoided if Na D-?O-hydroxybutyrate is substituted for the D,L-lactate in such fluids [Alam HB et al, J Am Col Surg 2001;193:255-63]. Lung damage after resuscitation, so called DaNang lung was a leading cause of post surgical death during the Viet Nam war. Although not admittedly, during 2003, the US fluid manufacturers changed the composition of Ringer's lactate from D,L to L lactate. This change was not done through submission of new data to FDA, but rather through the expedient of changing the definition of lactate in the US Pharmacopeia from a substance without optical rotation, to one with optical rotation. The inclusion of L-lactate in parenteral fluids, while an improvement over fluids containing D,L-lactate, is not optimum. Conditions requiring resuscitation are almost inevitably associated with hypoxia and lactic acidosis. Additional infusion of L-lactate worsens this condition and adds to the blockade of glycolysis, the major source of energy generation during periods of hypoxia as has been shown in studies by collaborators [Cross HR et al, J Mol Cell Cardiol 1995;27:1369-81]. It is our opinion that resuscitation fluids containing D-?O-hydroxybutyrate in place of L-lactate are preferable. In collaboration with the Naval Blood Laboratory, we are attempting to design and prepare such fluids made under cGMP conditions for testing in human subjects. A manuscript entitled "Severe adverse events associated with hemoglobin based oxygen carriers: role of resuscitative fluids and liquid preserved RBC" detailing the toxic effects of current resuscitation practices and how they can be avoided has been accepted for publication in the Journal of Trauma. SIGNIFICANCE OF THIS WORK TO THE PROGRAMS OF THIS INSTITUTE Ingestion of alcohol reduces the free [NAD+]/[NADH] ratio in cytoplasm of liver as does intravenous administration of l-lactate. Therefore this work has some significance to the work of this institute. However, this work is of greater significance to medical and surgical treatments in general particularly to the treatment of those engaged in combat or subject to injury from mass disasters.