Pyruvate oral rehydration solution improved visceral function and survival in shock rats

Advantages of pyruvate-based fluids in preclinical shock resuscitation-A narrative review

This review focuses on the innate beneficial effects of sodium pyruvate-based fluids, including pyruvate in intravenous solutions, oral rehydration solutions, and peritoneal dialysis solutions, on shock resuscitation with various animal models relative to current commercial fluids over the last two decades. Due to its superior pharmacological properties, pyruvate effectively sustains cytosolic glycolytic pathways and mitochondrial oxidative phosphorylation by restoration of redox potentials and reactivation of pyruvate dehydrogenase in hypoxia, even anoxia, and diabetes, reversing the Warburg effect and diabetic glucometabolic aberration. Pyruvate has been demonstrated to protect against multiorgan dysfunction and metabolic disturbance in numerous preclinical studies with various pathogenic injuries. The unique features of pyruvate potential clinical benefits encompass to efficiently correct lethal lactic acidosis via metabolically rapid consumption of intracellular [H⁺] and robustly protect multiorgan metabolism and function, particularly visceral organs in addition to the heart and brain, significantly prolonging survival in various animal models. Pyruvate protection of red blood cell function and preservation of the partial pressure of arterial oxygen should be highly concerned in further studies. Pyruvate is much advantageous over existing anions such as acetate, bicarbonate, chloride, and lactate in commercial fluids. Pyruvate-based fluids act as a therapeutic agent without causing iatrogenic resuscitation injury in addition to being a volume expander, indicating a potential novel generation of resuscitation fluids, including crystalloids and colloids. Pyruvate-based fluids have an enormous potential appeal for clinicians who face the ongoing fluid debate to readily select as the first resuscitation fluid. Clinical trials with pyruvate-based fluids in shock resuscitation are urgently warranted.

Pyruvate as a Potential Beneficial Anion in Resuscitation Fluids

There have been ongoing debates about resuscitation fluids because each of the current fluids has its own disadvantages. The debates essentially reflect an embarrassing clinical status quo that all fluids are not quite ideal in most clinical settings. Therefore, a novel fluid that overcomes the limitations of most fluids is necessary for most patients, particularly diabetic and older patients. Pyruvate is a natural potent antioxidant/nitrosative and anti-inflammatory agent. Exogenous pyruvate as an alkalizer can increase cellular hypoxia and anoxia tolerance with the preservation of classic glycolytic pathways and the reactivation of pyruvate dehydrogenase activity to promote oxidative metabolism and reverse the Warburg effect, robustly preventing and treating hypoxic lactic acidosis, which is one of the fatal complications in critically ill patients. In animal studies and clinical reports, pyruvate has been shown to play a protective role in multi-organ functions, especially the heart, brain, kidney, and intestine, demonstrating a great potential to improve patient survival. Pyruvate-enriched fluids including crystalloids and colloids and oral rehydration solution (ORS) may be ideal due to the unique beneficial properties of pyruvate relative to anions in contemporary existing fluids, such as acetate, bicarbonate, chloride, citrate, lactate, and even malate. Preclinical studies have demonstrated that pyruvate-enriched saline is superior to 0.9% sodium chloride. Moreover, pyruvate-enriched Ringer’s solution is advantageous over lactated Ringer’s solution. Furthermore, pyruvate as a carrier in colloids, such as hydroxyethyl starch 130/0.4, is more beneficial than its commercial counterparts. Similarly, pyruvate-enriched ORS is more favorable than WHO-ORS in organ protection and shock resuscitation. It is critical that pay attention first to improving abnormal saline with pyruvate for ICU patients. Many clinical trials with a high dose of intravenous or oral pyruvate were conducted over the past half century, and results indicated its effectiveness and safety in humans. The long-term instability of pyruvate aqueous solutions and para-pyruvate cytotoxicity is not a barrier to the pharmaceutical manufacturing of pyruvate-enriched fluids for ICU patients. Clinical trials with sodium pyruvate-enriched solutions are urgently warranted.

Mesenteric Lymph Drainage Improves Cardiac Papillary Contractility and Calcium Sensitivity in Rats with Hemorrhagic Shock

BACKGROUND

Myocardial dysfunction is an important adverse factor of hemorrhagic shock that induces refractory hypotension, and post-hemorrhagic shock mesenteric lymph (PHSML) return is involved in this adverse effect. This study investigated whether mesenteric lymph drainage (MLD) improves PHSML return-induced cardiac contractile dysfunction via the restoration of cardiomyocyte calcium sensitivity.

MATERIALS AND METHODS

A hemorrhage shock model was established by using a controlled hemorrhage through the femoral artery that maintained a mean arterial pressure of 40 ± 2 mmHg for 3 h. MLD and mesenteric lymph duct ligation (MLDL) were performed from 1 to 3 h during hypotension. The papillary muscles of the heart were collected for measurement of calmodulin expression and for determining contractile responses to either isoprenaline or calcium.

RESULTS

The results showed that either MLD or MLDL reversed the hemorrhagic shock-induced downregulation of calmodulin expression, a marker protein of cardiomyocyte calcium sensitization, in papillary muscles. MLD also improved the decreased contractile response and ±df/dt of the papillary muscle strip to gradient isoprenaline or calcium caused by hemorrhagic shock.

CONCLUSION

These findings indicate that increased cardiac contractibility may be associated with the restoration of calcium sensitivity produced by PHSML drainage.

Pyruvate-Enriched Oral Rehydration Solution Improves Glucometabolic Disorders in the Kidneys of Diabetic db/db Mice

Diabetes is prevalent worldwide, but ideally intensive therapeutic strategy in clinical diabetes and diabetic nephropathy (DN) is still lack. Pyruvate is protective from glucometabolic disturbances and kidney dysfunction in various pathogenic insults. Present studies focused on oral pyruvate effects on diabetes status and DN with 0.35% pyruvate in pyruvate-enriched oral rehydration solution (Pyr-ORS) and 1% pyruvate as drinking water for 8 weeks, using the model of diabetic db/db mice. Both Pyr-ORS and 1% pyruvate showed comparable therapeutic effectiveness with controls of body weight and blood sugar, increases of blood insulin levels, and improvement of renal function and pathological changes. Aberrant key enzyme activities in glucometabolic pathways, AR, PK, and PDK/PDH, were also restored; indexes of oxidative stress and inflammation, NAD⁺/NADH ratio, and AGEs in the kidneys were mostly significantly preserved after pyruvate treatments. We concluded that oral pyruvate delayed DN progression in db/db mice and the modified Pyr-ORS formula might be an ideal novel therapeutic drink in clinical prevention and treatment of type 2 diabetes and DN.

Pyruvate is a prospective alkalizer to correct hypoxic lactic acidosis

Type A lactic acidosis resulted from hypoxic mitochondrial dysfunction is an independent predictor of mortality for critically ill patients. However, current therapeutic agents are still in shortage and can even be harmful. This paper reviewed data regarding lactic acidosis treatment and recommended that pyruvate might be a potential alkalizer to correct type A lactic acidosis in future clinical practice. Pyruvate is a key energy metabolic substrate and a pyruvate dehydrogenase (PDH) activator with several unique beneficial biological properties, including anti-oxidant and anti-inflammatory effects and the ability to activate the hypoxia-inducible factor-1 (HIF-1α) - erythropoietin (EPO) signal pathway. Pyruvate preserves glucose metabolism and cellular energetics better than bicarbonate, lactate, acetate and malate in the efficient correction of hypoxic lactic acidosis and shows few side effects. Therefore, application of pyruvate may be promising and safe as a novel therapeutic strategy in hypoxic lactic acidosis correction accompanied with multi-organ protection in critical care patients.

Pyruvate in reduced osmolarity oral rehydration salt corrected lactic acidosis in sever scald rats

BACKGROUND

A novel pyruvate-based oral rehydration salt (Pyr-ORS) was demonstrated of superiority over bicarbonate- or citrate-based one to preserve organ function and correct lactic acidosis in rehydration of lethal shock in animals. This study further compared these effects between low-osmolar Pyr-ORS and equimolar citrate-based counterpart.

METHODS

Eighty rats, using a fatal burn shock model, were randomized into four groups (two subgroups per group: n = 10): the sham group (group SR), Pyr-ORS group (group PR), WHO-ORS III group (group CR), and no rehydration group. ORS was delivered by manual gavage during 24 h following burns. Oral administration consisted of half of counted volume in the initial 8 h plus the rest in the later 16 h. Systemic hemodynamics, visceral organ surface blood flow, organ function, and metabolic acidosis were determined at 8 h and 24 h after burn. Another set of rats with identical surgical procedures without tests was observed for survival.

RESULTS

Survival was markedly improved in the groups PR and CR; the former showed a higher survival rate than the latter at 24 h (40% versus 20%, P < 0.05). Systemic hemodynamics, visceral blood flow, and function of heart, liver, and kidney were greatly restored in group PR, compared with group CR (all P < 0.05). Hypoxic lactic acidosis was efficiently reversed in group PR, instead of group CR, (pH 7.36 versus 7.11, base excess 2.1 versus -9.1 mmol/L, lactate 4.28 versus 8.18 mmol/L; all P < 0.05) at 24 h after injury.

CONCLUSIONS

Pyruvate was advantageous over citrate in low-osmolar ORS for protection of organs and survival; pyruvate, but not citrate, in the ORS corrected hypoxic lactic acidosis in rats subjected to lethal burn shock in 24 h.

Pyruvate as a novel carrier of hydroxyethyl starch 130/0.4 may protect kidney in rats subjected to severe burns

BACKGROUND

The carrier of hydroxyethyl starch (HES) may play a critical role in kidney injury in fluid resuscitation. This study aimed mainly to compare effects of pyruvate-enriched saline with normal saline (NS) and acetate Ringer's (AR) solution as a carrier in HES130/0.4 on kidney function in rats subjected to severe burns.

METHODS

Using a lethal burn model, 140 rats were randomly allocated in seven groups (n = 20): sham group (group S); no fluid after burn (group N); burn resuscitated with NS (group NS); burn resuscitated with pyruvate saline (group PS); burn resuscitated with AR plus pyruvate-HES (group SP); burn resuscitated with AR plus acetate-HES (group SA), and burn resuscitated with AR plus NS-HES (group SN). A low volume (18.75 mL·kg^-1 during 12 h) of HES130/0.4 was infused with the ratio of 1:1 to crystalloids. Renal surface blood flow, blood creatinine and blood urea nitrogen, early sensitive indicators of kidney function: alpha-1 microglobulin, cystatin-C, and neutrophil gelatinase-associated lipocalin in blood and urine, and kidney tissue water contents were determined. Renal histopathological alterations with Paller scores were also measured at 8 h and 24 h after burn (n = 10), respectively.

RESULTS

The results showed in a comparable manner that group SP was the best in three HES groups and group PS was superior to group NS in renal preservation; group SP appeared significantly beneficial compared with group PS in renal surface blood flow, cystatin-C, neutrophil gelatinase-associated lipocalin, water contents, and Paller scores at 8-h or both time points after burn, respectively (all P < 0.05).

CONCLUSIONS

The carrier of HES130/0.4 played a crucial role in kidney injury in fluid resuscitation of rats subjected to severe burns. Pyruvate-enriched HES130/0.4 was superior and HES130/0.4, per se, might be not renocytotoxic, but renoprotective. Further studies are warranted.

Pyruvate in oral rehydration salt improves hemodynamics, vasopermeability and survival after burns in dogs

BACKGROUND

To investigate whether pyruvate-enriched oral rehydration solution (Pyr-ORS), compared with citrate-enriched ORS (Cit-ORS), improves hemodynamics and organ function by alleviating vasopermeability and plasma volume loss during intra-gastric fluid rehydration in dogs with severe burn.

METHODS

Forty dogs subjected to severe burn were randomly divided into four groups (n=10): two oral rehydrated groups with Pyr-ORS and Cit-ORS (group PR and group CR), respectively, according to the Parkland formula during the first 24h after burns. Other two groups were the intravenous (IV) resuscitation (group VR) with lactated Ringer's solution with the same dosage and no fluid rehydration (group NR). During the next 24h, all groups received the same IV infusion. The hemodynamics, plasma volume, vasopermeability and water contents and function of various organs were determined. Plasma levels of vascular endothelial growth factor (VEGF) and platelet activating factor (PAF) were detected by ELISA.

RESULTS

Hemodynamics parameters were significantly improved in group PR superior to group CR after burns. Levels of VEGF and PAF were significantly lower in group PR than in group CR. Organ function parameters were also greatly preserved in group PR, relative to groups CR and NR. Lactic acidosis was fully corrected and survival increased in group PR (50.0%), compared to group CR (20.0%).

CONCLUSION

Pyr-ORS was more effective than Cit-ORS in improving hemodynamics, visceral blood perfusion and organ function by alleviating vasopermeability-induced visceral edema and plasma volume loss in dogs with severe burn.

Pyruvate alleviates lipid peroxidation and multiple-organ dysfunction in rats with hemorrhagic shock

OBJECTIVE

Pyruvate can reduce lipid peroxidation, which plays a critical role in organ injury, in various models. However, it is not fully understood if this inhibition occurs in resuscitation of hemorrhagic shock (HS). This study examines effects of pyruvate Ringer solution (PR) in this respect in rats.

METHODS

Rats, subjected to 45% blood loss, were randomly allocated to the 3 groups (n = 18): HS with no fluid resuscitation (group NR), HS resuscitated with lactated Ringer solution (LR) (group LR), and HS resuscitated with PR (group PR). Mean arterial pressure, plasma levels of thiobarbituric acid reactive substances (TBARS), and superoxide dismutase were measured at various time points until 360 minutes after hemorrhage. Visceral organs were harvested at the end for evaluations of the TBARS, antioxidant enzyme, and tissue water content. Other 54 rats with identical procedures without sampling were documented for 24-hour survival rates (n = 18) after fluid resuscitation.

RESULTS

Pyruvate Ringer solution significantly increased mean arterial pressure and decreased blood TBARS levels after lethal HS. It also reduced TBARS concentrations and glutathione peroxidase activities but significantly enhanced glutathione reductase activities in most organs and greatly improved the ratios of reduced glutathione over oxidized glutathione in various organs in group PR, compared to group LR. Furthermore, PR significantly improved various organ function and water contents relative to LR. Group PR showed a more than 2-fold higher 24-hour survival rate of group LR.

CONCLUSIONS

Pyruvate Ringer solution alleviated organ edema and injury and prompted survival partially through inhibition of lipid peroxidation in various organs in severe HS rats.

Pyruvate Is Superior to Citrate in Oral Rehydration Solution in the Protection of Intestine via Hypoxia-Inducible Factor-1 Activation in Rats With Burn Injury

BACKGROUND

Recent studies have suggested that pyruvate-enriched oral rehydration solution (Pyr-ORS) may be superior to the standard bicarbonate-based ORS in the protection of intestine from ischemic injury. The aim of this study was to compare the effects of Pyr-ORS with citrate-enriched ORS (Cit-ORS) on the intestinal hypoxia-inducible factor-1 (HIF-1)-erythropoietin (EPO) signaling pathway for enteral rehydration in a rat model of burn injury.

METHODS

Rats were randomly assigned to 4 groups (N = 20, 2 subgroups each: n = 10): scald sham (group SS), scald with no fluid resuscitation (group SN), scald and resuscitation with enteral Cit-ORS (group SC), and scald and resuscitation with enteral Pyr-ORS (group SP). At 2.5 and 4.5 hours after a 35% total body surface area (TBSA) scald, intestinal mucosal blood flow (IMBF), contents of HIF-1, EPO, endothelial nitric oxide synthase (eNOS), nitric oxide (NO), barrier protein (ZO-1), levels of serum diamine oxidase (DAO), and intestinal mucosal histology injury score were determined.

RESULTS

Serum DAO activities in the scalded groups were significantly elevated, but less raised in group SP than in group SC, at 2.5 hours and at 4.5 hours after the scald. Further, group SP more profoundly preserved intestinal HIF-1 expression compared with group SC at the 2 time points. Compared with group SC, group SP had markedly elevated intestinal EPO, eNOS, and NO levels at the same time points, respectively (P < .05). Similarly, IMBF and ZO-1 levels were significantly higher in group SP than in group SC. Intestinal mucosal histopathological scores were statistically higher at 2.5 hours and 4.5 hours after scalding but were more attenuated in group SP than in group SC (P < .05). Immunofluorescence expression of intestinal mucosal ZO-1 was consistent with the above changes. The above parameters were also significantly different between groups SC and SN (all P < .05).

CONCLUSION

Pyr-ORS provides a superior option to Cit-ORS for the preservation of intestinal blood flow and barrier function and the attenuation of histopathological alterations in enteral resuscitation of rats with burn injury. Its underlying mechanism may be closely related to the pyruvate in activation of intestinal HIF-1-EPO signaling cascades.