Increased Lactate Levels Research Articles

Upregulated hexokinase 2 expression induces the apoptosis of dopaminergic neurons by promoting lactate production in Parkinson's disease

Parkinson's disease (PD) is characterized by impaired mitochondrial function and decreased ATP levels. Aerobic glycolysis and lactate production have been shown to be upregulated in dopaminergic neurons to sustain ATP levels, but the effect of upregulated glycolysis on dopaminergic neurons remains unknown. Since lactate promotes apoptosis and α-synuclein accumulation in neurons, we hypothesized that the lactate produced upon upregulated glycolysis is involved in the apoptosis of dopaminergic neurons in PD. In this study, we examined the expression of hexokinase 2 (HK2) and lactate dehydrogenase (LDH), the key enzymes in glycolysis, and lactate levels in the substantia nigra pars compacta (SNpc) of a MPTP-induced mouse model of PD and in MPP+-treated SH-SY5Y cells. We found that the expression of HK2 and LDHA and the lactate levels were markedly increased in the SNpc of MPTP-treated mice and in MPP+-treated SH-SY5Y cells. Exogenous lactate treatment led to the apoptosis of SH-SY5Y cells. Intriguingly, lactate production and the apoptosis of dopaminergic neurons were suppressed by the application of 3-bromopyruvic acid (3-Brpa), a HK2 inhibitor, or siRNA both in vivo and in vitro. 3-Brpa treatment markedly improved the motor behaviour of MPTP-treated mice in pole test and rotarod test. Mechanistically, lactate increases the activity of adenosine monophosphate-activated protein kinase (AMPK) and suppresses the phosphorylation of serine/threonine kinase 1 (Akt) and mammalian target of rapamycin (mTOR). Together, our data suggest that upregulated HK2 and LDHA and increased lactate levels prompt the apoptosis of dopaminergic neurons in PD. Inhibition of HK2 expression attenuated the apoptosis of dopaminergic neurons by downregulating lactate production and AMPK/Akt/mTOR pathway in PD.

Insulin gene expression and functional activity of insulin signaling pathway in Alzheimer's disease

Aim. To study the insulin (INS) gene expression, insulin and lactate levels, expression of Fe65 adapter protein, and level of oxidative DNA damage marker γH2AX in different brain areas in the experimental model of Alzheimer's disease.Materials and Methods. Male, 4-month-old C57BL/6 mice received either intrahippocampal injection of β-amyloid (C57BL/6 + Aβ 1-42) or phosphate-buffered saline (C57BL/6 + PBS). Insulin (INS) gene expression in the hippocampus and amygdala was assessed by means of reverse transcription-polymerase chain reaction. Levels of lactate and insulin in different brain areas were measured by enzyme-linked immunosorbent assay. Expression of Fe65 adapter protein and γH2AX in the hippocampus was studied by immunofluorescence staining followed by confocal microscopy.Results. We found an overexpression of the INS gene in the hippocampus and amygdala, an increase in lactate level in the hippocampus, and slightly increased insulin level in the amygdala of mice with Alzheimer's disease as compared with the control group. Neurodegeneration was accompanied by an elevated endothelial expression of Fe65 adapter protein (p= 0.04) and γH2AX in hippocampal neurons (p = 0.04).Conclusion. Alzheimer's disease neurodegeneration is accompanied by a disrupted insulin signaling and impaired glucose metabolism in the hippocampus and amygdala. This further leads to a neuronal accumulation of γH2AX and impaired amyloid precursor protein proteolysis because of insulin inability to inhibit its interaction with the Fe65 adapter protein and to prevent formation and deposition of β-amyloid.

Use of cardiac troponin I (cTnI) levels to diagnose severe hypoxia and myocardial injury induced by perinatal asphyxia in neonatal dogs

Prolonged perinatal asphyxia and subsequent severe hypoxia are the main causes of mortality in neonatal dogs in the first days of life. In medicine, specific cardiac biochemical markers, such as troponin I, are used to diagnose ischemic and nonischemic myocardial injury in asphyxiated newborns after birth. Thus, the objectives of this study were to compare the levels of cardiac troponin I (cTnI) between asphyxiated and nonasphyxiated newborn dogs and evaluate the correlations of cTnI levels with the modified Apgar score, the levels of oxygen saturation, blood glucose, and lactatemia, and blood gas parameters. This study aimed to determine the possible use of cTnI as a marker of severe hypoxia and myocardial ischemic injury in neonatal dogs. Fifteen animals in a eutocic vaginal delivery group (VG), 15 animals in a cesarean section group (CG), and 13 animals in a hypoxia (asphyxiated) group (HG) were evaluated. The animals in the asphyxiated group were from dystocic deliveries and born by vaginal delivery or cesarean section. All groups were evaluated at birth and after 60 min. The newborns in the VG and CG exhibited mixed acidosis (respiratory acidosis due to increased partial pressure of CO2 (pCO2) and metabolic acidosis due to reduced pH and bicarbonate (HCO3) levels, base excess/deficit in the extracellular fluid compartment (BEecf), and increased lactate levels) due to transient physiological hypoxemia at birth. The cTnI levels in the VG and CG were within the reference standards for healthy dogs. No correlations between cTnI level and the other parameters were observed in the VG and CG. Newborns in the HG exhibited prominent mixed acidosis (p < 0.05) due to severe hypoxemia. The Apgar score and blood gas parameters showed that these dogs were born asphyxiated, and they presented low vitality and the need for resuscitation maneuvers. The cTnI levels in the HG were significantly higher than those in the VG and CG (p < 0.05) and above the reference standards for healthy dogs, which indicated ischemic myocardial injury. The cTnI level was negatively correlated (p < 0.05) with the parameters Apgar score, heart rate, peripheral oxygen saturation (sO2) level, reflex score, and total carbon dioxide (TCO2) level and positively correlated (p < 0.01) with lactate level. This study showed that asphyxiated newborn dogs have higher serum cTnI levels than nonasphyxiated newborn dogs; thus, the cTnI can be used as a marker of severe hypoxia and ischemic myocardial damage in newborn dogs.

Extracellular vesicles derived from tumour cells as a trigger of energy crisis in the skeletal muscle.

BackgroundCachexia, a syndrome frequently occurring in cancer patients, is characterized by muscle wasting, altered energy and protein metabolism and impaired myogenesis. Tumour‐derived microvesicles (TMVs) containing proteins, messenger RNAs (mRNAs), and non‐coding RNAs could contribute to cancer‐induced muscle wasting.MethodsDifferential ultracentrifugation was used to isolate TMVs from the conditioned medium of Lewis lung carcinoma and C26 colon carcinoma cell cultures. TMVs were added to the culture medium of C2C12 myoblasts and myotubes for 24–48–72 h, and the effects on protein and energy metabolism were assessed. TMVs were also isolated from the blood of C26‐bearing mice. MicroRNA (miR) profile of TMVs was obtained by RNA‐seq and validated by digital drop PCR. Selected miRs were overexpressed in C2C12 myoblasts to assess the effects on myogenic differentiation.ResultsDifferentiation was delayed in C2C12 myoblasts exposed to TMVs, according to reduced expression of myosin heavy chain (MyHC; about 62% of controls at Day 4) and myogenin (about 68% of controls at Day 4). As for myotubes, TMVs did not affect the expression of MyHC, while revealed able to modulate mitochondria and oxidative metabolism. Indeed, reduced mRNA levels of PGC‐1α (C = 1 ± 0.2, TMV = 0.57 ± 0.06, normalized fold change, P < 0.05) and Cytochrome C (C = 1 ± 0.2, TMV = 0.65 ± 0.04, normalized fold change, P < 0.05), associated with increased BNIP3 expression (C = 1 ± 0.1, TMV = 1.29 ± 0.2, normalized fold change, P < 0.05), were observed, suggesting reduced mitochondrial biogenesis/amount and enhanced mitophagy. These changes were paralleled by decreased oxygen consumption (C = 686.9 ± 44 pmol/min, TMV = 552.25 ± 24 pmol/min, P < 0.01) and increased lactate levels (C = 0.0063 ± 0.00045 nmol/μL, TMV = 0.0094 ± 0.00087 nmol/μL, P < 0.01). A total of 118 miRs were found in MVs derived from the plasma of the C26 hosts; however, only three of them were down‐regulated (RNA‐seq): miR‐181a‐5p (−1.46 fold change), miR‐375‐3p (−2.52 fold change), and miR‐455‐5p (−3.87 fold change). No correlation could be observed among miRs in the MVs obtained from the blood of the C26 host and those released by C26 cells in the culture medium. Overexpression of miR‐148a‐3p and miR‐181a‐5p in C2C12 myoblasts revealed the ability to impinge on the mRNA levels of Myf5, Myog, and MyHC (Myh4 and Myh7).ConclusionsThese results show that in C2C12 cultures, TMVs are able to affect both differentiation and the mitochondrial system. Such effects could be related to TMV‐contained miRs.

Normal Saline Solution or Lactated Ringer's Solution to Enhance Lactate Clearance in Septic Patients After Initial Resuscitation in the ED: A Retrospective Cohort Trial.

ObjectiveTo compare the effect of isotonic crystalloid solutions between lactated Ringer’s solution (LRS) and normal saline solution (NSS) on lactate clearance in septic patients at the emergency department (ED).Materials and MethodsThis study is a single-center retrospective chart review. The study enrolled patients older than 18 years with sepsis and initial serum lactate level >2 mg/dL in the ED. The primary outcome was to determine which isotonic solution was better for serum lactate clearance in septic patients. The secondary outcomes were serum creatinine change within 24 h and the 48-h survival rate after admission.ResultsA total of 120 patients were enrolled with a median crystalloid volume administered in the ED of 1000 mL. Within 2 h of resuscitation, there was no difference in lactate clearance between the LRS and NSS groups with median values of 29.2% and 25%, respectively (P=0.839). The 48-h survival rate after admission did not differ between the LRS and NSS groups with median values of 90% and 86%, respectively. Both isotonic solutions increased serum creatinine levels within 24 h of treatment with median values of 0.3 for each group (P=0.647).ConclusionAmong septic patients in the ED treated with NSS or LRS, there was no difference in lactate clearance, serum creatinine change within 24 h, or 48-h survival. However, several factors were associated with increased lactate levels, such as older age and use of vasopressors and immunosuppressive agents.

Diagnostic Values of Venous Peak Lactate, Lactate-to-pyruvate Ratio, and Fold Increase in Lactate from Baseline in Aerobic Exercise Tests in Patients with Mitochondrial Diseases.

Objective Although aerobic exercise tests on cycle ergometry have long been used for initial assessments of cases of suspected mitochondrial disease, the test parameters in patients with final diagnoses of other diseases via the widely used 15 W for 15 minutes exercise protocol have not been fully characterized. Methods We retrospectively reviewed all patients who underwent the test at our institution. We classified the patients with genetic diagnoses or those who met previously reported clinical criteria as having mitochondrial diseases and those with a final diagnosis of another disease as having other diseases. Results were available from 6 patients with mitochondrial disease and 15 with other diseases. Results During the test, elevated venous peak lactate above the upper normal limit of healthy controls at rest [19.2 mg/dL (2.13 mM)] was observed in 3 patients with mitochondrial diseases (50.0%) and 5 with other diseases (33.3%). In the group of patients with elevated venous peak lactate, a lactate-to-pyruvate ratio of >20 was observed in all 3 patients with mitochondrial disease but in only 1 of the 5 with other diseases. More than a 2-fold increase in venous lactate from baseline was observed in 4 patients with mitochondrial disease (66.7%) and 1 with another disease (6.7%). Conclusion Elevated venous peak lactate levels were observed in patients with final diagnoses of other diseases, even under a low 15-minute workload at 15 W. The lactate-to-pyruvate ratio and increase in lactate level from baseline may add diagnostic value to venous peak lactate levels alone.

The toxicity of 1,3,4-thiadiazolium mesoionic derivatives on hepatocarcinoma cells (HepG2) is associated with mitochondrial dysfunction

Mesoionic compounds, 4-phenyl-5-(4-X-cinnamoyl)-1,3,4-thiadiazolium-2-phenylamine chloride derivatives (MI-J: X = OH; MI-D: X = NO2), possess significant antitumor and cytotoxic effects on several cancer cells. In this work, we evaluated the cytotoxicity of MI-J and MI-D on human hepatocellular carcinoma (HepG2 cells) grown in either high glucose (HG) or galactose medium (GAL) to clarify whether the effects of mesoionics on mitochondrial bioenergetics are associated with their cytotoxicity in these cells. MI-J and MI-D (5–50 μM) decreased the viability of HepG2 cells in a dose- and time-dependent manner, as assessed by MTT, LDH release and dye with crystal violet assays. Both compounds at lower (5 μM) and intermediate (25 μM) concentrations were more toxic to cells grown in GAL medium. MI-J inhibited the basal state of respiration in HepG2 cells cultured in HG and GAL media; however, in GAL medium, this effect occurred at the lowest concentration (5 μM). A leak-state stimulus was observed only after incubation with MI-J (5 μM) for GAL medium. MI-D stimulated and inhibited the leak state in cells grown in HG medium at concentrations of 5 μM and 25 μM, respectively. In cells cultured in GAL medium, respiration was strongly inhibited by MI-D at the highest concentration (25 μM). In contrast, at 5 μM, the mesoionic inhibited the basal and uncoupled states at 30% and 50%, respectively. The inhibition of the basal state by MI-J and MI-D was consistent with the increase in lactate levels in both media, which was higher for the GAL medium. Both mesoionics slightly decreased pyruvate levels only in cells cultured in GAL medium. Additionally, MI-J (25 μM) reduced the ATP amount in cells cultured in both media, while MI-D (25 μM) promoted a reduction only in cells grown in GAL medium. Our results show that MI-J and MI-D depress mitochondrial respiration and consequently change metabolism and reduce ATP levels, effects associated with their toxicity in hepatocarcinoma cells.

A Pectin-Rich, Baobab Fruit Pulp Powder Exerts Prebiotic Potential on the Human Gut Microbiome In Vitro

Increasing insight into the impact of the gut microbiota on human health has sustained the development of novel prebiotic ingredients. This exploratory study evaluated the prebiotic potential of baobab fruit pulp powder, which consists of pectic polysaccharides with unique composition as compared to other dietary sources, given that it is rich in low methoxylated homogalacturonan (HG). After applying dialysis procedures to remove simple sugars from the product (simulating their absorption along the upper gastrointestinal tract), 48 h fecal batch incubations were performed. Baobab fruit pulp powder boosted colonic acidification across three simulated human adult donors due to the significant stimulation of health-related metabolites acetate (+18.4 mM at 48 h), propionate (+5.5 mM at 48 h), and to a lesser extent butyrate (0.9 mM at 48 h). Further, there was a trend of increased lactate levels (+2.7 mM at 6h) and reduced branched chain fatty acid (bCFA) levels (−0.4 mM at 48 h). While Bacteroidetes levels increased for all donors, donor-dependent increases in Bifidobacteria, Lactobacilli, and Firmicutes were observed, stressing the potential interindividual differences in microbial composition modulation upon Baobab fruit pulp powder treatment. Overall, Baobab fruit pulp powder fermentation displayed features of selective utilization by host microorganisms and, thus, has promising prebiotic potential (also in comparison with the ‘gold standard’ prebiotic inulin). Further research will be required to better characterize this prebiotic potential, accounting for the interindividual differences, while aiming to unravel the potential resulting health benefits.

The Role of Salivary Lactate Levels in assessing the Severity of Septic Shock

Background:Sepsis is a major worldwide cause of morbidity and mortality. Hence, rapid and reliable diagnosis is essential. Emergency departments use a standard measure of sepsis, based upon an elevated Lactate level in blood. Saliva is more readily available and easier to obtain than blood samples, and is increasingly being studied as a new source of diagnostic information.Aim:This study aimed to evaluate whether analysis of Lactate levels in saliva can substitute for that of Lactate levels in blood.Methods/Materials:We processed saliva samples and serum samples from septic shock and non-septic shock patients. We found out Lactate levels in both the group. We plotted the concentration of Lactate in non-septic and septic patients and compared lactate levels in saliva to its levels in blood.Statistical analysis: Results were statistically analyzed by independent sample t test and A Spearman rho correlationResults:We found increased serum and salivary Lactate levels in all cases of sepsis compared to the control group. Notably, the increase in Lactate levels was higher in serum as compared to saliva in septic patients, suggesting saliva may not serve as a better indicator of sepsis compared to blood. Salivary lactate was more in septic shock patients compared to non-septic shock patients.Conclusions:To our knowledge, this is the first study to compare lactic acid levels in serum and saliva in cases of sepsis. The increase in serum lactate in patients with sepsis is evident when compared to increase in salivary lactate, so serum lactate level would be easier for physicians to differentiate septic patients from non-septic patients. Salivary lactate may not serve as better indicator in septic shock patients.

Potential use of lactate for the treatment of neonatal hypoxic-ischemic encephalopathy.

Potential use of lactate for the treatment of neonatal hypoxic-ischemic encephalopathy.

Decreased Brain pH and Pathophysiology in Schizophrenia.

Postmortem studies reveal that the brain pH in schizophrenia patients is lower than normal. The exact cause of this low pH is unclear, but increased lactate levels due to abnormal energy metabolism appear to be involved. Schizophrenia patients display distinct changes in mitochondria number, morphology, and function, and such changes promote anaerobic glycolysis, elevating lactate levels. pH can affect neuronal activity as H+ binds to numerous proteins in the nervous system and alters the structure and function of the bound proteins. There is growing evidence of pH change associated with cognition, emotion, and psychotic behaviors. Brain has delicate pH regulatory mechanisms to maintain normal pH in neurons/glia and extracellular fluid, and a change in these mechanisms can affect, or be affected by, neuronal activities associated with schizophrenia. In this review, we discuss the current understanding of the cause and effect of decreased brain pH in schizophrenia based on postmortem human brains, animal models, and cellular studies. The topic includes the factors causing decreased brain pH in schizophrenia, mitochondria dysfunction leading to altered energy metabolism, and pH effects on the pathophysiology of schizophrenia. We also review the acid/base transporters regulating pH in the nervous system and discuss the potential contribution of the major transporters, sodium hydrogen exchangers (NHEs), and sodium-coupled bicarbonate transporters (NCBTs), to schizophrenia.

Clinical Characteristics and In-Hospital Mortality of Cardiac Arrest Survivors in Brazil: A Large Retrospective Multicenter Cohort Study.

Data on cardiac arrest survivors from developing countries are scarce. This study investigated clinical characteristics associated with in-hospital mortality in resuscitated patients following cardiac arrest in Brazil. Retrospective analysis of prospectively collected data. Ninety-two general ICUs from 55 hospitals in Brazil between 2014 and 2015. Adult patients with cardiac arrest admitted to the ICU. None. We analyzed 2,296 patients (53% men; median 67 yr (interquartile range, 54-79 yr]). Eight-hundred patients (35%) had a primary admission diagnosis of cardiac arrest suggesting an out-of-hospital cardiac arrest; the remainder occurred after admission, comprising an in-hospital cardiac arrest cohort. Overall, in-hospital mortality was 83%, with only 6% undergoing withholding/withdrawal-of-life support. Random-effects multivariable Cox regression was used to assess associations with survival. After adjusting for age, sex, and severity scores, mortality was associated with shock (adjusted odds ratio, 1.25 [95% CI, 1.11-1.39]; p < 0.001), temperature dysregulation (adjusted odds ratio for normothermia, 0.85 [95% CI, 0.76-0.95]; p = 0.007), increased lactate levels above 4 mmol/L (adjusted odds ratio, 1.33 [95% CI, 1.1-1.6; p = 0.009), and surgical or cardiac cases (adjusted odds ratio, 0.72 [95% CI, 0.6-0.86]; p = 0.002). In addition, survival was better in patients with probable out-of-hospital cardiac arrest, unless ICU admission was delayed (adjusted odds ratio for interaction, 1.63 [95% CI, 1.21-2.21]; p = 004). In a large multicenter cardiac arrest cohort from Brazil, we found a high mortality rate and infrequent withholding/withdrawal of life support. We also identified patient profiles associated with worse survival, such as those with shock/hypoperfusion and arrest secondary to nonsurgical admission diagnoses. Our findings unveil opportunities to improve postarrest care in developing countries, such as prompt ICU admission, expansion of the use of targeted temperature management, and implementation of shock reversal strategies (i.e., early coronary angiography), according to modern guidelines recommendations.

Clinical and Laboratory Correlates of Acute Respiratory Failure in Patients with COVID-19 Depending on the Values of Transcutaneous Saturation

With a traditional approach to treatment of hypoxemic respiratory failure, it is believed that SpO2 reduction below 88-90% during oxygen therapy requires emergency care including invasive mechanical ventilation. However, the manifestations of hypoxemic respiratory failure in COVID-19 patients have certain features that have led to the change in the traditional respiratory support procedure. The therapeutic goals of respiratory support in this category of patients require clarification.The objective: in patients with COVID-19, to study the relationship of transcutaneous saturation values with clinical indicators that characterize ARF, the state of acid-base balance and blood gas composition.Subjects and methods. A multicenter prospective observational study included 90 COVID-19 patients treated in ICU whose transcutaneous saturation (SpO2) values were below 93% despite treatment. Depending on the degree of impaired oxygenation, patients underwent oxygen therapy through a mask or nasal cannula, high-flow oxygenation or non-invasive ventilation, while it was not always possible to achieve the target values of oxygenation parameters. The patients were divided into the following groups: Group 1 ‒ SpO2 above 93%, Group 2 ‒ SpO2 within 93–90%, Group 3 ‒ SpO2 within 85–89%, Group 4‒ SpO2 within 80–84%, Group 5 ‒ SpO2 within 75–79%, and Group 6 – below 75%.Results. It was revealed that during ARF management by noninvasive methods, different values of transcutaneous saturation and corresponding changes in the acid-base balance (ABB) and blood gas composition were determined When transcutaneous saturation (SpO2) decreased to 85%, there was a corresponding moderate decrease in PaO2 while no metabolic changes occurred. As a rule, there were no obvious clinical signs of respiratory failure (silent hypoxia). In patients with SpO2 reduction down 80–85%, clinical signs of respiratory failure (dyspnea, tachypnea, agitation) and, as a rule, a moderate increase in PаCO2 with the development of respiratory acidosis and compensatory metabolic alkalosis were noted. When SpO2 decreased down to 75–79%, arterial hypoxemia was usually accompanied by moderate hypercapnia and the development of decompensated mixed acidosis and venous desaturation as well as increased lactate levels. With transcutaneous saturation going below 74%, these changes were even more pronounced and were observed in all patients of this group.Conclusion. The revealed changes are mostly consistent with generally accepted ideas about the relationship between values of transcutaneous saturation and blood gas composition and parameters of blood ABB in the case of ARF. Reduction of transcutaneous saturation down to 85% not accompanied by pronounced clinical signs of respiratory failure (dyspnea, tachypnea, agitation), development of acidosis and venous desaturation, and the elevated lactate level can be regarded as relatively safe.

Correlation between Intraoperative Serum Lactate and New-Onset Postoperative Neurodeficits in Patients Undergoing Elective Craniotomies

Background:Elevated lactate levels in neurosurgical patients are seen in brain tumors, traumatic brain-injury, brain infarction, and subarachnoid hemorrhage. Hyperlactatemia during craniotomy may be caused by hypotension due to multiple factors. Recently, intraoperative hyperlactatemia has been associated with fresh-onset neurodeficits.Aims:We studied the prevalence of hyperlactatemia in patients undergoing craniotomy and relationship between intraoperative hyperlactatemia and development of new postoperative neurodeficit.Study Design:Eighty-six patients, American Society of Anesthesiologists Classes I,II and III, undergoing elective craniotomy for neurosurgical indications were included in this prospective, observational study in a tertiary care center.Materials and Methods:Baseline, intraoperative, and postoperative (upto 12 h) lactate levels were noted. Neurological examination to detect new-onset neurodeficits was done at intervals up to 72 h postoperatively. Lactate levels were compared between patients who developed neurodeficits and those who did not develop neurodeficits postoperatively.Statistical Analysis:Statistical analysis of the correlation between intraoperative hyperlactatemia and fresh postoperative neurodeficit was done using the Chi-square test.Results:The prevalence of intraoperative hyperlactatemia was found to be 52.3% and that of fresh-onset postoperative neurodeficits was 31.4%. The relationship between the two was statistically insignificant (P > 0.05).Conclusion:The intraoperative hyperlactatemia is not correlated with the development of fresh-onset postoperative neurodeficit.Implications:There may be no relationship between the intraoperative lactate levels and fresh-onset postoperative neurodeficits. Multifactorial reasons may be responsible for increased lactate levels which need to be identified by further research.

Juvenile social isolation leads to schizophrenia-like behaviors via excess lactate production by astrocytes

Repeated early environmental deprivation is regarded as a typical paradigm to mimic the behavioral abnormalities and brain dysfunction that occur in psychiatric disorders. Previously, we reported that social isolation could disrupt prepulse inhibition (PPI) in Sprague-Dawley (SD) rats, producing the typical characteristics of a schizophrenia animal model. Based on further analysis of previous proteomic and transcriptomic data, a disrupted balance of glucose metabolism was found in the prefrontal cortex (PFC) of isolated rats. Subsequently, in the first experiment of this study, we investigated the effects of juvenile social isolation (postnatal days (PND) 21–34) on PPI and lactate levels in PND56 rats. Compared with the social rearing group, rats in the isolated rearing group showed disrupted PPI and increased lactate levels in the PFC. In the second experiment, at PND55, the model rats were acutely injected with a glycogen phosphorylase inhibitor (4-dideoxy-1,4-imino-darabinitol, DAB) or control saline in the bilateral PFC. Our data showed that acute DAB administration (50 pmol, 0.5 μl) significantly improved the disrupted PPI and decreased the levels of oxidative phosphorylation (OXPHOS)-related mRNAs as well as lactate. In summary, our results suggested that excess astrocytic lactate production was involved in the impairment of auditory sensory gating of isolated rats, which may contribute to the metabolic pathogenesis of schizophrenia.

Inhibition of Oxphos with Iacs-010759 Depletes AML Leukemia Initiating Cells (LIC) in Vitro and Improves Survival in Pre-Clinical AML Models

Introduction: Metabolic reprogramming of energy-generating pathways is a core oncogenic property of leukemias and other cancers that provides a potential therapeutic vulnerability.In light of recent studies demonstrating reliance of Leukemia Initiating Cells (LIC) on OxPhos (Skrtic et al., 2011; Lagadinou at al., 2013), we aimed to determine the effects of OxPhosi on AML bulk and LICs in vitro and in vivo using patient-derived xenograft (PDX) AML models.Methods and Results: Our gene set enrichment analysis conducted on publicly available gene expression profiles of LIC-enriched populations (Ng et al., 2016) confirmed significant enrichment of OxPhos-related genes relative to no LIC. Using transmission electron microscopy (TEM), we found a significant increase in mitochondria numbers in 8 primary CD34+ AML samples compared with 3 healthy bone marrow (hBM) CD34+ sample (19±8 vs 8±1,p=0.01, Fig. 1A), consistent with previously reported data (Škrtić at al.,2011). This finding provides rationale for assessing OxPhos as a potential target for therapeutic intervention.IACS-010759 is a novel potent inhibitor of OxPhos (OxPhosi) that blocks cellular respiration through inhibition of mitochondrial complex I (Molina et al., AACR2016).In 80% of the AML samples studied (n=50), IACS-010759 exposure induced profound growth-inhibitory effects in vitro at an EC50 of 3.1nM (0.1-11.7nM) and 5.0 nM (0.9-12.8nM) in AML blasts and CD34+ AML LIC respectively, with minimal toxicity against hBM CD34+ cells. In line with viability data, OxPhosi reduced colony forming ability of LIC (n=5, EC50 13-30nM) but not of hBM CD34+ cells. Further, IACS-010759 induces differentiation of CD34+ cells in a subset of AML samples as determined by flow cytometric analysis of colonies collected after treatment. Next, profound reduction of both, oxygen-dependent ATP production and spare respiratory capacity (SRC), at IC50s of 20.5 nM (range, 1.3*10-5 -528) for bulk and 51.4 nM (range, 1.3-528) for CD34+ cells, was shown by Seahorse assay. This translated into the mitochondrial membrane potential loss (TMRE, JC1 flow cytometry), mitochondria swelling and degeneration shown by TEM.Based on genomic characteristics and responses to OxPhosi in vitro, two distinct groups of patients (pts) with unique metabolic pattern based on SRC were identified: samples from pts with low SRC (36.3±17.4 pmol/min) enriched in IDH1/2-mutated AML were sensitive to IACS-010759 with median 60% of viability drop at 123 nM, while samples with high SRC (86.7±20), enriched in TP53-mutated AML were resistant to OxPhosi with 30% viability reduction (p=0.03).The proteome studies of AML pts samples revealed dose-dependent increased expression of energy stress response protein pAMPK, upregulation of glycolysis marker PFKFB and decrease of the fatty acids oxidation markers CPT1 and ACC1.Further, the intracellular metabolome analysis of LIC from 4 primary AML pts showed modulation of amino acids (AA) with increased level of glutamine and aspartate, decreased TCA intermediates and increased lactate level indicative of OxPhos perturbation. In contrast, only moderate decrease of AA level and TCA intermediates was observed in hBM cells, consistent with lack of cytotoxicity on hBM. In a PDX model from MLL-rearranged AML refractory to standard chemotherapy, IACS-010759 treatment prolonged survival and delayed disease progression (Molina et al., AACR 2016). Mass cytometry analysis of BM and spleen cells demonstrated decrease of LIC (CD34+, CD38-, CD123+, CD33+), relative increase of CD11c+ differentiated cells and suppression of proliferation measured by Ki67 (Fig. 1B). The depletion of LIC by OxPhosi was confirmed in a secondary transplantation experiment. Mice injected with similar numbers of BM AML cells isolated from primary engrafted recipients of vehicle, Ara-C or IACS-010759 , showed improvement of the overall survival in OxPhosi arm (Fig. 1C).Conclusion: Our study demonstrates that inhibiting OxPhos with IACS-010759 constitutes a novel promising therapeutic approach that targets a unique metabolic vulnerability of AML LICs via energy depletion, inhibition of proliferation and induction of differentiation. We have shown for the first time that IDH1/2 mutated AML have low spared respiratory capacity and are highly sensitive to IACS-010759. These findings are being tested in an ongoing Phase 1 clinical trial of IACS-010759 in AML (NCT02882321). [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Effects of extensive bleeding in pigs on laboratory biomarkers.

BackgroundDuring hemorrhage and resuscitation, clinical and laboratory monitoring is useful to guide further management. However, acute changes in the biochemistry due to blood loss and subsequent crystalloid fluid resuscitation have not been fully studied.Materials and methodsTwelve anesthetized, juvenile pigs were used. Atraumatic exsanguination, corresponding to a total blood loss of 40%, was performed through a catheter and completed 2 h after initiation of the experiment. Arterial samples were analyzed by point-of-care testing and venous samples were analyzed. Oxygen delivery was calculated.ResultsShortly after 40% hemorrhage and concomitant fluid supplementation, there were significant reductions in arterial hemoglobin and hematocrit (approximately 25%, respectively). Oxygen delivery was less than half of the baseline value. Lactate in arterial blood was more than doubled after 40% exsanguination. On average, no other clinically significant changes in any of the analytes were observed, but interindividual dispersion was pronounced.ConclusionsAcute exsanguination was associated with decreased hemoglobin and hematocrit levels and increased lactate levels but limited effects on the other biomarkers that were studied. Increased levels of biomarkers in severely bleeding patients could indicate tissue damage and the source should be further investigated.

Study of secretome deregulation of a rat model of endotoxemic shock using a non-targeted mass spectrometry approach

The secretome is a set of proteins secreted by a cell at a given time and under certain conditions. The secretome, easily accessible from plasma and analyzable by a proteomic approach, represents a good opportunity to identify biomarkers in septic shock. This pathology corresponds to a systemic inflammatory response syndrome related to an infection and associated with cardiocirculatory failure leading to organ dysfunction with a mortality rate of 40%. The identification of diagnostic/prognostic biomarkers is crucial to improve patient outcome. Study the secretome of a rat model of endotoxemic shock to identify relevant deregulated proteins (DEP). Endotoxemic shock was induced by lipopolysaccharides injection (LPS, S. enterica typhi, 0.5 mg/kg, iv) and compared to controls (Ringer lactate, iv). Under isoflurane anesthesia, carotid cannulation allowed evaluation of mean arterial blood pressure (MAP), heart rate and blood sampling (T0, and T50 or T90 min on EDTA and protease inhibitor). Plasma was analyzed with tandem MS based on a label free quantification. Gene ontology (GO) analyses defined several groups of biological process (BP) in which the DEP were involved. Ninety minutes after shock induction, the LPS group present a reduction in MAP (−45%, P < 0.05) and increased lactate levels (+27%, P < 0.05). Proteomic analyses revealed 6 and 22 DEP, such as Ribonuclease 4, in the LPS group respectively at T50 and T90. At T50 and T90 Go-BP show common alterations in response to oxidative stress, tissue remodeling and coagulation. This study proposes an approach to identify DEP in septic shock. DEP need to be tested in cellular models in order to understand their role in the physiopathology of shock and to improve understanding of adaptations of the secretome during sepsis. The link between our results and patient prognosis will need to be studied for clinical use.

Metabolomics reveal dynamic host responses in lipid, amino acid, and energy metabolism after acute exposure of gut microbiota in germ‐free rats

Background Integrating germ-free and gnotobiotic models have advanced the understanding of how gut microbiome impacts host physiology. High-throughput omics technologies further provide microbial and metabolite targets for translational purposes. Yet, limited knowledge is known about the immediate effects of natural microbial colonization on host lipid, amino acid, and energy metabolism. Methods To address this, germ-free Sprague Dawley rats were acclimated with the gut microbiota by cohousing them with microbiota-intact rats (1:1 ratio) for 10 days. Characterization of the microbiota composition in the feces was quantified by 16S ribosomal RNA gene sequencing. Cecal metabolites related to primary microbial and secondary host-bacterial co-metabolisms (e.g., tricarboxylic acid cycle, anaerobic fermentation, amino acids) were analyzed by H1-NMR based metabolomics. Targeted metabolomic analysis of serum eicosanoids and leukotrienes were examined by liquid chromatography-mass spectrometry. Gas chromatography was used for analysis of hepatic total fatty acids. Results Natural colonization of the gut microbiota by coprophagy was sufficient to reconstitute the gut microbiota in conventionalized germ-free (GFC) rats. Among the colonizing bacteria, Akkermansia spp. was one of the top abundant genera in GFC rats and thus, could be one of the main contributors to the elevation of inosine and its metabolites, hypoxanthine and xanthine, in the cecal contents. Additionally, catabolism of choline to trimethylamine and dimethylamine was diminished, but there were no changes in creatine levels. GFC rats also exhibited more aromatic (e.g., tyrosine) and acidic (e.g., glutamate) amino acids, but less carboxamide-chained (e.g., glutamine, asparagine) amino acids. Increase of lactate levels suggested a favorability for anaerobic fermentation even though elevated succinate and fumarate indicated functional tricarboxylic acid cycle activity. These changes in energy and amino acid metabolism were paralleled in the serum of GFC rats. Analyzing hepatic lipid fractions revealed an increase of both ω6 and ω3 fatty acids in GFC rats, including their eicosanoid and leukotriene derivatives in circulation (e.g., leukotriene 4; 15S-hydroxy-5Z,8Z,11Z13E,17X-eicosapentaneoic acid). Conclusion This study demonstrates that acute exposure to the gut microbiota causes dynamic metabolic changes in the gut-liver axis.

Melatonin prevented the increased serum lactate levels and the reduced hemoglobin levels in burn-induced Wistar rats

Background: Burns are the most common and devastating form of trauma yet constitute a common cause of morbidity worldwide. Complications of burns such as sepsis and tissue hypoperfusion may increase serum lactate and reduce hemoglobin. Measuring lactate levels has been proven to be a useful predictive marker of hypoperfusion and sepsis in patients with burns. Melatonin which acts as an anti-inflammatory and antioxidant, has been proposed to be used as pharmacological adjuvant in patients with burns, reducing oxidative damage. The study aims to investigate the effects of melatonin supplementation on serum lactate and hemoglobin levels in burn-induced male Wistar rats.Method: This was an experimental animal study with randomized control group design. All samples (n=12 male Wistar rats) were randomized and divided into two groups. Each rat was exposed to a hot metal rod for 10 seconds to induce 30% burns injury. Rats in the control group were administered with placebo (aquadest), while rats in the experimental group were administered with melatonin intraperitoneally at 0, 8, and 16 hours after burns injury. Blood samples were collected from the retro-orbital sinuses at 0, 3, and 24 hours after treatment. Data were statistically analyzed using Paired t-Test, Independent t-Test Mann-Whitney Rank Test and Wilcoxon test.Results: There were no significant differences in lactate and hemoglobin levels between melatonin group and control group 0 hours after treatment (T0), 3 hours after treatment (T3), and 24 hours after treatment (T24) (p&gt;0.05). There were increased lactate levels and decreased hemoglobin levels in both melatonin and control groups, however the increment of lactate and the decrement of hemoglobin were steeper in control group compared to melatonin group. There were higher serum lactate increments and higher hemoglobin decrement at 24 hours (∆T0–T24) in control compared to melatonin group (p&lt;0.05).Conclusion: Melatonin might prevent dramatic rise of serum lactate levels and decrease of hemoglobin levels until 24 hours after treatment in burns injury. If confirmed by further studies, melatonin might have a role as adjuvant therapy in burns.