Ringer's Ethyl Pyruvate Solution Research Articles

Ringer's ethyl pyruvate solution attenuates hypoperfusion and renal injury after multivisceral ischemia-reperfusion in rabbits.

Ringer's ethyl pyruvate solution (REPS) has been protective against experimental renal, intestinal, and spinal ischemia and may be useful for organ protection in major vascular surgery. The purpose of this study was to investigate whether REPS attenuates organ injury in a rabbit model of supraceliac aortic cross-clamp that simulates thoracoabdominal aortic surgery. Following the Institutional Animal Care and Use Committee's approval, 20 rabbits were undergone cross-clamping of the supraceliac thoracic aorta for 30min, and observed for 180min after reperfusion. Either REPS (33mg/kg/h of ethyl pyruvate) or Ringer's lactate solution were infused throughout the study period. Arterial pressure and aortic blood flow were continuously monitored. Blood lactate concentration, serum transaminase levels, neutrophil activation, and urinary N-acetyl-beta-glucosaminidase (NAG) activity were evaluated. After reperfusion, supraceliac aortic blood flow was significantly higher, and urinary NAG was significantly lower in animals that received REPS, while the other parameters were not significantly different. In conclusion, REPS attenuated the reduction of aortic blood flow and urinary NAG elevation after the cross-clamp of supraceliac aorta.

Effects of ethyl pyruvate on leukocyte-endothelial interactions in the mesenteric microcirculation during early sepsis treatment

OBJECTIVES:Experimental studies on sepsis have demonstrated that ethyl pyruvate is endowed with antioxidant and anti-inflammatory properties. This study aimed to investigate the effects of ethyl pyruvate on leukocyte-endothelial interactions in the mesenteric microcirculation in a live Escherichia coli-induced sepsis model in rats.METHODS:Male Wistar rats were administered an intravenous suspension of E. coli bacteria or were subjected to a sham procedure. Three hours after bacterial infusion, the rats were randomized into the following groups: a control group without treatment, a group treated with lactated Ringer's solution (4 mL/kg, i.v.), and a group treated with lactated Ringer's solution (4 mL/kg, i.v.) plus ethyl pyruvate (50 mg/kg). At 24 h after bacterial infusion, leukocyte-endothelial interactions were investigated using intravital microscopy, and the expression of P-selectin and intercellular adhesion molecule-1 was evaluated via immunohistochemistry. White blood cell and platelet counts were also determined at baseline and 3 h and 24 h after E. coli inoculation.RESULTS:The non-treated and lactated Ringer's solution-treated groups exhibited increases in the numbers of rolling leukocytes (∼2.5-fold increase), adherent cells (∼3.0-fold), and migrated cells (∼3.5-fold) compared with the sham group. In contrast, treatment with Ringer's ethyl pyruvate solution reduced the numbers of rolling, adherent and migrated leukocytes to the levels observed in the sham group. Additionally, the expression of P-selectin and intercellular adhesion molecule-1 was significantly increased on mesenteric microvessels in the non-treated group compared with the sham group (p<0.001). The expression of both adhesion molecules was reduced in the other groups, with ethyl pyruvate being more effective than lactated Ringer's solution. Infusion of bacteria caused significant leukopenia (3 h), followed by leukocytosis with granulocytosis (24 h). There was also an intense and progressive reduction in the number of platelets. However, no differences were observed after treatment with the different solutions.CONCLUSIONS:The presented data suggest that ethyl pyruvate efficiently reduces the inflammatory response in the mesenteric microcirculation in an experimental model of sepsis induced by live E. coli and is associated, at least in part, with down-regulation of P-selectin and intercellular adhesion molecule-1.

Protective effects of ethyl pyruvate in cisplatin-induced nephrotoxicity

This study was performed to investigate the effect of ethyl pyruvate on changes in renal functions and oxidative stress related renal injury caused by cisplatin (cis-dichlorodiammine platinum-II; CDDP).Male Wistar albino rats were divided into four groups (n = 8): (1) control group (1 ml Ringer's lactate solution i.p.); (2) ethyl pyruvate (EP) group (50 mg/kg Ringer's EP solution (REPS) i.p.); (3) cisplatin group (a single dose of cisplatin (5 mg/kg, i.p.); and (4) cisplatin + EP group (a single dose of cisplatin (5 mg/kg, i.p.) + REPS 50 mg/kg/day, i.p.) for five days. At the sixth day, kidneys of rats were mounted to a Langendorff apparatus. Renal perfusion pressures were recorded. Blood samples were taken for serum urea, creatinine, total oxidant status (TOS), total antioxidant status (TAS) and oxidative stres index (OSI) evaluations. Kidney tissues were obtained for malondialdehyde (MDA) analyses and histopathological examination.Perfusion pressures, serum urea, creatinine, TOS, OSI and tissue MDA levels were found significantly higher, whereas TAS was notably lower in cisplatin group. Histopathological examination showed apparent renal paranchymal injury in cisplatin group. In cisplatin + REPS group, perfusion pressures, serum urea, creatinine and tissue MDA levels were decreased. Moreover, EP co-administration provided less inflammatory cell infiltration, tubular dilatation, whereas TOS, TAS and OSI improved significantly versus cisplatin group.These findings show that EP has protective effects against cisplatin nephrotoxicity.

Ethyl pyruvate enhances intra-resuscitation hemodynamics in prolonged ventricular fibrillation arrest

Aims As the duration of untreated cardiac arrest increases, the effectiveness of standard therapies declines, and may be more harmful than helpful. We investigated the hemodynamic, metabolic and anti-inflammatory effects of Ringer's ethyl pyruvate solution (REPS) versus Ringer's solution (RS) in the acute model of prolonged porcine arrest. Methods Seventeen mixed-breed swine were induced into ventricular fibrillation (VF) and left untreated for 8 min. CPR was begun using a mechanical chest compression device at a rate of 100 per minute. At the onset of CPR, animals were randomly assigned to treatment with either 25 mL/kg of RS or 25 mL/kg of REPS containing 40 mg/kg of ethyl pyruvate, infused over 5 min in blinded fashion. CPR continued with administration of a drug cocktail at 2 min and the first rescue shock was delivered at minute 13 of VF. Animals having ROSC were supported with standardized care for 2 h. Results Both groups had 100% ROSC and 100% 2-h survival. The REPS group exhibited higher median CPP (27.3 mmHg) than the control group (16.5 mmHg) by 3 min of CPR, which continued throughout the duration of CPR ( p = 0.02). The median time to hypotension following ROSC was 9.64 min in the REPS group and 7.25 min in controls ( p = 0.04) and there was a non-significant trend of decreased use of vasopressors for the duration of resuscitation. There was no difference in systemic or cerebral metabolism between groups. There were non-significant trends of decreased IL-6, increased Il-10 and decreased mesenteric bacterial colony growth in those treated with REPS when compared to RS. Conclusions The administration of REPS with CPR significantly improved intra- and post-resuscitation hemodynamics in this swine model of prolonged cardiac arrest, but did not definitely change the metabolic or inflammatory profile during the acute resuscitation period.

Ethyl Pyruvate Prevents Intestinal Inflammatory Response and Oxidative Stress in a Rat Model of Extrahepatic Cholestasis

Ringer's ethyl pyruvate solution (REPS) has been shown to ameliorate liver injury in a murine model of extrahepatic cholestasis. The goal of the present investigation was to gain additional information about whether infusing REPS instead of Ringer's lactate solution (RLS) after inducing obstructive jaundice would be beneficial to intestinal barrier function, inflammatory response, and oxidative stress. Male Sprague Dawley rats were divided into three groups: Group Sham (n=6), sham-treated controls; Group RLS (n=9), common bile duct ligation (CBDL) plus RLS; and Group REPS (n=9), CBDL plus REPS. On 14 d after BDL, the rats were sacrificed and intestinal permeability was analyzed. Ileal IL-6 and TNF-alpha levels, malondialdehyde (MDA), glutathione (GSH), myeloperoxidase (MPO), and NF-kappaB activity were determined. Histologic examination and apoptosis of ileum were also examined. Relative to sham-treated controls, CBDL in RLS-treated rats were associated with increased intestinal permeability to FITC-labeled dextran (4.51+/-0.85 versus 0.44+/-0.18, P<0.01), histopathologic damage and apoptosis (68.4+/-13.4 versus 6.7+/-1.9 pre-1000 villi cells, P<0.01). IL-6 and TNF-alpha level, MDA, MPO, and NF-kappaB activity in ileal tissues were also promoted, along with decreased GSH levels. Treatment with REPS significantly decreased intestinal permeability (3.37+/-0.71, P<0.01) and apoptosis (42.8+/-14.3 pre-1000 villi cells, P<0.01). Other changes were also significantly attenuated by treatment with REPS after CBDL. The present study demonstrates that administration of REPS, but not RLS, maintains intestinal barrier function and reduces intestinal oxidative damage, inflammatory response, and apoptosis in cholestatic rats. This effect of ethyl pyruvate may be useful for preventing intestinal injury in patients with biliary obstruction.

Ethyl pyruvate reduces germ cell–specific apoptosis and oxidative stress in rat model of testicular torsion/detorsion

Purpose Testicular torsion/detorsion (T/D) results in enhanced formation of free radical metabolites, which contributes to the pathophysiology of tissue damage. We investigated the protective effects of ethyl pyruvate (EP) against testis tissue damage in an experimental model of testicular torsion. Methods Sprague-Dawley rats were divided into 5 groups. In those animals that underwent T/D, right testes were rotated 720° for 1 hour. Group 1 control rats underwent sham operation. In group 2, the rats underwent T/D. The EP was prepared and injected in the form of Ringer's ethyl pyruvate solution. The rats in group 3, 4, and 5 received 2 doses of 20, 50, and 100 mg/kg EP (30 minutes before and after detorsion), respectively. The right testes of 6 animals from each group were excised 4 hours after detorsion for the measurement of lipid peroxidation, myeloperoxidase (MPO), and antioxidant enzymes activities. Germ cell apoptosis was determined in right testes of 8 animals per group 24 hours after detorsion. The epididymal sperm concentration and motility were evaluated 1 month after treatments. Results Germ cell apoptosis indices were significantly higher in group 2 compared with control group. The level of lipid peroxidation and MPO activity increased, whereas antioxidant enzymes activities decreased after T/D. Sperm count and motility were also reduced 1 month after T/D in group 2 rats. However, EP treatment at doses of 50 and 100 mg/kg significantly decreased the early apoptotic damage and improved long-term sperm count and motility. In the same dosing groups, we observed normalization of oxidant/antioxidant balance and decrement of MPO activity. However, administration of 20 mg/kg of EP conferred no protective effect. Conclusions Administration of Ringer's ethyl pyruvate solution (in appropriate doses) is protective against apoptotic tissue damage following testicular torsion and improves long-term testicular function. The antioxidant and anti-inflammatory properties of EP seem responsible for the protective effects. Our findings suggest this resuscitation solution as a possible substitute for fluid and electrolyte maintenance during surgical detorsion.

HYPOXIA ACTIVATES c-JUN N-TERMINAL KINASE VIA RAC1-DEPENDENT REACTIVE OXYGEN SPECIES PRODUCTION IN HEPATOCYTES

The earliest events after the induction of hemorrhagic shock (HS) are complex and poorly understood. We have recently demonstrated that decreased tissue perfusion and hypoxia during HS lead to an increased phosphorylation of c-Jun N-terminal kinase (JNK) in vivo. The purpose of these investigations was to test the hypothesis that hypoxia activates JNK via Rac1-dependent reactive oxygen species (ROS) signaling. Mice subjected to HS and resuscitated with Ringer's ethyl pyruvate solution (REPS) or N-acetylcysteine (NAC), two scavengers of ROS, demonstrated decreased levels of phosphorylated JNK. Exposure of primary mouse hepatocytes in culture to 1% oxygen led to increased production of ROS and phosphorylation of JNK. The duration of hypoxia correlated with the level of generation of ROS and JNK activation. The phosphorylation of JNK was attenuated in the presence of ROS scavengers or the nicotinamide adenosine dinucleotide phosphate [NDA(P)H] oxidase inhibitor, diphenyleneiodonium (DPI). In addition, hypoxia increased activation of Rac1. Inhibition of Rac1 activation by adenoviral gene transfer of dominant-negative Rac1 (AdRac1) attenuated both ROS formation and JNK activation. Together, these data suggest that ROS generation during hypoxia in the liver directly leads to JNK activation in a Rac1-dependent process.

Haemodynamic and metabolic effects of resuscitation with Ringer’s ethyl pyruvate in the acute phase of porcine endotoxaemic shock

Ethyl pyruvate has been shown to possess anti-inflammatory and free radical scavenging properties. However, the haemodynamic effects of ethyl pyruvate have not been studied in detail. We investigated the systemic, regional and microcirculatory haemodynamic and metabolic effects of resuscitation with Ringer's ethyl pyruvate solution (REPS) vs. Ringer's acetate (RA) in an acute model of porcine endotoxaemic shock. Fourteen anaesthetized pigs received an infusion of endotoxin that was increased stepwise over 30 min to a rate of 2.5 microg/kg/h. After 60 min of endotoxaemia, the animals were resuscitated with either ethyl pyruvate 40 mg/kg, given as REPS, or the equivalent volume of RA, administered over 10 min. Thereafter, an infusion of either ethyl pyruvate 40 mg/kg/h, given as REPS, or the equivalent volume of RA, was started, and the maintenance fluid was reduced so that the total amount of fluid given was kept constant. The experiment was terminated after 300 min of endotoxaemia. Endotoxin infusion led to a hypodynamic state that was reversed by fluid resuscitation after 60 min. Progressive deterioration ensued and, after 300 min, all animals were again hypodynamic. No differences in response to treatment were found between the groups with regard to systemic haemodynamics, renal artery or portal vein flow or microcirculatory flow in the liver, kidney, ileal serosa or mucosa. Metabolic acidosis and increased arterial blood lactate developed in both groups, but, in the REPS group, the base excess was significantly lower from 150 min and the anion gap was significantly higher at 150 and 210 min. We could not demonstrate any difference between REPS and RA for resuscitation in this model of acute porcine endotoxaemic shock.

Ethyl pyruvate reduces liver injury in a murine model of extrahepatic cholestasis.

Ethyl pyruvate has been shown to ameliorate liver injury and decrease expression of several proinflammatory cytokines when used to treat mice with hemorrhagic shock or alcoholic hepatitis. Herein we sought to determine whether delayed treatment with ethyl pyruvate dissolved in a Ringer's-type balanced salt solution--Ringer's ethyl pyruvate solution (REPS)--would be beneficial in a murine model of common bile duct ligation (CBDL)-induced liver injury. Male C57BL/6 mice were subjected to a sham (n = 6) procedure or CBDL (n = 27). Twenty-four hours after operation, mice subjected to CBDL were randomized to receive treatment with either REPS (40 mg/kg of ethyl pyruvate per dose) or Ringer's lactate solution (RLS) every 8 h over a 72 h period. Compared with sham-treated controls, CBDL in RLS-treated mice was associated with histological evidence of hepatocellular necrosis as well as significant increases in the plasma concentrations of alanine aminotransferase and total bilirubin. Relative to sham-treated controls, CBDL in RLS-treated mice also was associated with increased hepatic lipid peroxidation and increased hepatic expression of transcripts for TNF, IL-6, and iNOS. All of these changes were significantly attenuated by delayed treatment with REPS after CBDL. In the RLS-treated group, CBDL was associated with increased NF-kappaB DNA binding in nuclear extracts prepared from liver tissue. Treatment with REPS increased NF-kappaB DNA binding still further. CBDL was associated with increased hepatocellular apoptosis in both the RLS- and REPS-treated groups. These data support the view that ethyl pyruvate ameliorates hepatic inflammation, lipid peroxidation, and necrosis in mice subjected to CBDL. Ethyl pyruvate warrants further evaluation as an adjunctive treatment to ameliorate liver injury from extrahepatic biliary obstruction.

Ethyl pyruvate ameliorates acute alcohol-induced liver injury and inflammation in mice

Ethyl pyruvate dissolved in a calcium-containing balanced salt solution—Ringer's ethyl pyruvate solution (REPS)—ameliorates ileal mucosal hyperpermeability and decreases the expression of several proinflammatory genes when it is used instead of Ringer's lactate solution (RLS) to resuscitate mice from hemorrhagic shock. Herein, we sought to determine whether delayed treatment with REPS would be beneficial in a murine model of acute alcoholic liver injury associated with binge drinking. Mice were gavaged with 3 doses of ethanol (5 g/kg each dose) over a 12-hour period and then randomized to treatment with 3 intraperitoneal doses of REPS or RLS over 12 hours. Compared with sham-treated controls not subjected to alcohol intoxication, RLS-treated mice demonstrated histologic evidence of fatty change and piecemeal necrosis of hepatocytes in the liver, as well as a significant increase in the plasma concentration of alanine aminotransferase. Biochemical changes induced by alcohol administration included increased hepatic lipid peroxidation, nuclear factor-κB activation, and tumor necrosis factor-α messenger RNA expression. All of these alcohol-induced effects were ameliorated by treatment with REPS instead of RLS. These data support the view that treatment with REPS ameliorates the hepatic inflammatory response and decreases hepatocellular injury in mice subjected to acute alcohol intoxication.

The Therapeutic Potential of Ethyl Pyruvate for the Management of Ischemia/Reperfusion Syndromes, Sepsis and Sepsis‐Related Organ Dysfunction, and Other Conditions Associated With Excessive Inflammation

SUMMARYPyruvate, the final product of glycolysis and the starting substrate for the tricarboxylic acid cycle, plays a central role in intermediary metabolism. It is also an effective scavenger of reactive oxygen species. In order to take advantage of the beneficial effects of pyruvate while circumventing the problem of its poor stability in solution, our laboratory formulated the ester derived from pyruvic acid and ethanol, namely ethyl pyruvate, in a Ringer's‐type calcium‐ and potassium‐containing balanced salt solution. Ringer's ethyl pyruvate solution (REPS) has been evaluated in preclinical studies using animal models of mesenteric ischemia/reperfusion injury, hemorrhagic shock, acute endotoxemia, sepsis, and severe acute alcoholic hepatitis. Treatment with REPS, when compared with treatment with Ringer's lactate solution, has been shown to be able to improve survival and decrease expression of proinflammatory mediators. REPS warrants further evaluation for the resuscitation of patients with hemorrhagic shock and a variety of acute inflammatory conditions.

Ringer’s Ethyl Pyruvate Solution: A Novel Resuscitation Fluid for the Treatment of Hemorrhagic Shock and Sepsis

Reactive species of oxygen have been implicated as being important mediators in a variety of pathologic conditions, including burns, various forms of ischemia/reperfusion injury, and hemorrhagic shock. Pyruvate, an intermediate in the metabolism of glucose, is a potent reactive species of oxygen scavenger. Pyruvate, however, is unstable in aqueous solutions, and has not been developed as a therapeutic agent. Ethyl pyruvate, a simple derivative of the parent compound, is thought to be more stable in solution. Ringer's ethyl pyruvate solution (REPS) has been evaluated in a number of preclinical studies using animal models of mesenteric ischemia/reperfusion injury, hemorrhagic shock, and acute endotoxemia. Treatment with REPS, when compared with treatment with Ringer's lactate solution, has been shown to be able to improve survival and decrease expression of proinflammatory mediators. REPS warrants further evaluation for the resuscitation of patients with hemorrhagic shock.

Resuscitation with Ringer's ethyl pyruvate solution prolongs survival and modulates plasma cytokine and nitrite/nitrate concentrations in a rat model of lipopolysaccharide-induced shock.

The glycolytic intermediate, pyruvate, is capable of scavenging reactive oxygen species (ROS). However, this compound is relatively unstable and hence is not useful as a therapeutic agent. Ethyl pyruvate, a simple derivative of pyruvate, appears to be more stable, and when formulated in a calcium-containing Ringer's-type balanced salt solution (REPS), has been shown to be salutary in rat models of two pathophysiological conditions--mesenteric ischemia/reperfusion and hemorrhagic shock/resuscitation--that are thought to be mediated, at least in part, by ROS. Because ROS also have been implicated in the pathogenesis of lipopolysaccharide (LPS)-induced shock, we carried out a series of experiments to determine if REPS is beneficial in this condition. Anesthetized rats were challenged with intravenous LPS (20 mg/kg). When mean arterial pressure (MAP) decreased to 60 mmHg, 3- to 5-mL boluses of either REPS (n = 10) or Ringer's lactate solution (RLS; n = 10) were infused as needed to prevent MAP from decreasing further. By design, the maximal volume of fluid infused was 7 mL/kg. Resuscitation with REPS as compared with RLS prolonged survival time (498 +/- 48 min vs. 362 +/- 30 min; P = 0.0014). Resuscitation with REPS as compared with RLS also was associated with significantly lower circulating concentrations of nitrite/nitrate and interleukin (IL)-6 and higher plasma levels of IL-10. These data support the view that delayed treatment with REPS modulates the inflammatory response to LPS, and prolongs survival time in a lethal model of endotoxic shock.

Ringer's ethyl pyruvate solution ameliorates ischemia/reperfusion-induced intestinal mucosal injury in rats.

Pyruvate has been shown to be protective in numerous in vitro and in vivo models of oxidant-mediated cellular or organ system injury. Unfortunately, the usefulness of pyruvate as a therapeutic agent is abrogated by its very poor stability in solution. In an effort to take advantage of the ability of pyruvate to scavenge reactive oxygen species while avoiding the problems associated with the instability of pyruvate in solution, we sought to determine whether a simple derivative, ethyl pyruvate, would be protective in an animal model of reactive oxygen species-mediated tissue injury, namely mesenteric ischemia and reperfusion in rats. Prospective, randomized trial. Animal research center. Male Sprague-Dawley rats. Under general anesthesia, rats were subjected to 60 mins of mesenteric ischemia followed by 60 mins of reperfusion. Controls (n = 6) received intravenous lactated Ringer's solution according this dosing schedule: 1.5 mL/kg bolus before ischemia, 3.0 mL/kg bolus before resuscitation, and 1.5 mL.kg-1.hr-1 by continuous infusion. Two experimental groups received similar volumes of either pyruvate (n = 6 each) or ethyl pyruvate (n = 9) solution made up exactly like lactated Ringer's solution except for the substitution of either pyruvate or ethyl pyruvate for lactate, respectively. To obtain tissues for assessing mucosal permeability and histology, five 10-cm long segments of small intestine were obtained at the following time points: baseline, after 30 and 60 mins of ischemia, and after 30 and 60 mins of reperfusion. Mucosal permeability to fluorescein isothiocyanate dextran (molecular weight 4000 Da) was assessed ex vivo by using an everted gut sac method. Compared with controls, treatment of rats with either pyruvate solution or ethyl pyruvate solution significantly ameliorated the development of intestinal mucosal hyperpermeability during the reperfusion. Treatment with ethyl pyruvate solution also significantly decreased the extent of histologic mucosal damage after mesenteric reperfusion. Treatment with Ringer's ethyl pyruvate solution ameliorated structural and functional damage to the intestinal mucosa in a rat model of mesenteric ischemia/reperfusion. Ethyl pyruvate solution warrants further evaluation as a novel therapeutic agent for preventing oxidant-mediated injury in various disease states.