Blood Pyruvate Research Articles

A novel high-stability bioelectrochemical sensor based on sol-gel immobilization of lactate dehydrogenase and AuNPs-rGO signal enhancement for serum pyruvate detection

Pyruvate participates in diverse metabolic pathways in the body and is normally present in human blood at 40–120 μM, with concentrations outside this range associated with various diseases. Therefore, accurate and stable blood pyruvate level tests are necessary for effective disease detection. However, traditional analytical techniques require complicated instrumentation and are time consuming and expensive, prompting researchers to develop improved methods based on biosensors and bioassays. Here, we designed a highly stable bioelectrochemical pyruvate sensor affixed to a glassy carbon electrode (GCE). To maximize biosensor stability, 0.1 U of lactate dehydrogenase was affixed to the GCE using a sol-gel process, resulting in generation of Gel/LDH/GCE. Next, 2.0 mg/mL AuNPs-rGO was added to enhance current signal strength, resulting in generation of the bioelectrochemical sensor Gel/AuNPs-rGO/LDH/GCE. AuNPs-rGO synthesized in advance was verified as correct using transmission electron microscopy and UV–Vis, Fourier-transform infrared and X-ray photoelectron spectroscopy. Pyruvate detection conducted via differential pulse voltammetry in phosphate buffer (pH 7.4, 100 mM) at 37 °C for 1–4500 μM pyruvate provided detection sensitivity as high as 254.54 μA/mM/cm2. The reproducibility, regenerability and storage stability were analyzed with the relative standard deviation of 5 bioeletrochemical sensors detection was 4.60% and biosensor accuracy after 9 cycles was 92%, with accuracy remaining at 86% after 7 days. In the presence of D-glucose, citric acid, dopamine, uric acid and ascorbic acid, the Gel/AuNPs-rGO/LDH/GCE sensor exhibited excellent stability, high anti-interference ability and better performance than conventional spectroscopic methods for detection of pyruvate in artificial serum.

P-092: RED BLOOD CELL GLUCOSE CONSUMPTION AND METABOLISM IN SICKLE CELL DISEASE

Purpose: Glucose is the single most essential component of the red blood cells (RBCs), being its sole energy provider and therefore is implicated in the energy metabolomics of the RBCs. This in turn play a crucial role in RBC lifespan, which in Sickle Cell Disease (SCD) patients is reduced to about 20 days from the usual average 120 days. This motivated us to investigate the process of glucose consumption and metabolism in red blood cells of Sickle Cell Patient of Odisha. Materials and methods: Blood samples of homozygous SCD patients (HbSS) were collected randomly with informed consent from different parts of Odisha state depending on the availability and accessibility of the subjects. The samples were studied for their hematological and biochemical parameters including levels of glucose. The red blood cells of SCD patients aged and sex matched normal (HbAA) as well as sickle cell traits (HbAS) were separated and incubated for different time intervals to measure the glucose consumption and Pyruvate and Lactate formation. Along with this the membrane stability of the cells were estimated and time dependent glucose uptake was also carried out. Identification of the haemoglobin variant was done by performing sickling test, haemoglobin electrophoresis and HPLC Hb. Variant analysis. All the biochemical estimations were done following the standard methods. Results: In the red blood cells of SCD cases (HbSS), the levels of glucose consumption were noted to be the higher than the sickle cell trait (HbAS) cases and control/normal (HbAA) samples. Concurrently, formation of blood Pyruvate and Lactate showed higher rate in comparison to HBAA and HbAS red cells indicating raised metabolic turnover in the sickle RBCs. In the time dependent study, the red cells of HbSS patients showed higher rate of glucose consumption compared to trait and normal cells. This data also correlates with the higher hemolytic features of the RBCs showing lower membrane stability with increased metabolism. Conclusion: The sickle cell mutation causes much more damage to the life of RBCs than mere morphological sickling of cells. The energy consumption plays a vital role in the life span, shape, stability and overall biochemistry of the RBCs, thus being a critical factor of RBC metabolism, which in turn determines the overall blood-based health of the SCD patients. Understanding and pin-pointing the key factors of energy metabolism thus holds many potential and promising factors in controlling the sickling, and indeed overall health of patients in case of sickle cell disease. The authors do not declare any conflict of interest

AMPK/SIRT1 Deficiency Drives Adjuvant-Induced Arthritis in Rats by Promoting Glycolysis-Mediated Monocytes Inflammatory Polarization.

BackgroundExact roles of many metabolic regulators in rheumatoid arthritis (RA) are to be clarified. This study aimed to further characterize the impacts of silent information regulator 1 (SIRT1) status changes on this disease.MethodsFluctuation pattern of SIRT1 expression in adjuvant-induced arthritis (AIA) rats was monitored using periodically collected white blood cells. Another bath of AIA rats were treated by SIRT1 agonist resveratrol. Blood from these rats was used to separate monocytes and plasma, which were subjected to polymerase chain reaction (PCR), enzyme linked immunosorbent assay (ELISA), and biochemical analyses. Clinical implication of SIRT1 activation was verified by treating AIA rat monocytes with SIRT1 agonist and overexpression vector in vitro.ResultsSIRT1 deficiency occurred in AIA rats, which was accompanied with down-regulation of interleukin 10 (IL-10) and arginase-1 (ARG-1). Resveratrol eased oxidative stress and increased IL-10 production in vivo. Results of ELISA analysis demonstrated that resveratrol attenuated AIA severity in rats. Furthermore, it restored the altered levels of triglyceride, lactate and pyruvate in blood. Resveratrol promoted IL-10 production, and suppressed glycolysis of AIA monocytes cultured in vitro. SIRT1 overexpression similarly reshaped differentiation profile of AIA monocytes, evidenced by changes in metabolism indicators, IL-10 production and AMP-activated protein kinase (AMPK) pathway status. Although overexpressing SIRT1 in normal cells did not affect glycolysis significantly, it attenuated AMPK antagonist-caused abnormality.ConclusionSIRT1 deficiency is implicated in AIA-related immune abnormality and metabolism alteration. Activating this signaling with resveratrol would impair the inflammatory polarization of monocytes, and consequently ease the severity of RA.

A Case of Early Diagnosis of Pyruvate Dehydrogenase Complex Deficiency: The Use of Next-Generation Sequencing

Introduction: Pyruvate dehydrogenase complex deficiency (PDHD) is a rare genetic mitochondrial disorder that is characterized by the broad clinical manifestations from lactic acidosis in neonate to chronic neurodegenerative conditions. Incidence and prevalence of PDHD are unknown because of early lethality and difficulty of diagnosis. Case Presentation: We report a case of preterm male infant born at 31 + 3/7 weeks gestation with a birth weight of 1,310 g by cesarean section. He presented with scoliosis, polydactyly and severe metabolic acidosis at birth. Corpus callosum agenesis and increased parenchymal echogenicity were detected by cranial ultrasound. Pyruvate and lactate in blood and CSF were elevated, and lactate-pyruvate ratio was normal. Next-generation sequencing (NGS) technique identified a novel PDHA1 mutation, c.1157-1162del (p.Phe386Lys387del) on X chromosome in him and his mother. Conclusions: PDHD is a rare and fatal disease in case of neonatal onset. This case demonstrates early diagnosis of PDHD in preterm infant using NGS technique.

Analysis of 13 C and 14 C labeling in pyruvate and lactate in tumor and blood of lymphoma-bearing mice injected with 13 C- and 14 C-labeled pyruvate.

Measurements of hyperpolarized 13C label exchange between injected [1‐13C]pyruvate and the endogenous tumor lactate pool can give an apparent first‐order rate constant for the exchange. The determination of the isotope flux, however, requires an estimate of the labeled pyruvate concentration in the tumor. This was achieved here by measurement of the tumor uptake of [1‐14C]pyruvate, which showed that <2% of the injected pyruvate reached the tumor site. Multiplication of this estimated labeled pyruvate concentration in the tumor with the apparent first‐order rate constant for hyperpolarized 13C label exchange gave an isotope flux that showed good agreement with a flux determined directly by the injection of non‐polarized [3‐13C]pyruvate, rapid excision of the tumor after 30 s and measurement of 13C‐labeled lactate concentrations in tumor extracts. The distribution of labeled lactate between intra‐ and extracellular compartments and the blood pool was investigated by imaging, by measurement of the labeled lactate concentration in blood and tumor, and by examination of the effects of a gadolinium contrast agent and a lactate transport inhibitor on the intensity of the hyperpolarized [1‐13C]lactate signal. These measurements showed that there was significant export of labeled lactate from the tumor, but that labeled lactate in the blood pool produced by the injection of hyperpolarized [1‐13C]pyruvate showed only relatively low levels of polarization. This study shows that measurements of hyperpolarized 13C label exchange between pyruvate and lactate in a murine tumor model can provide an estimate of the true isotope flux if the concentration of labeled pyruvate that reaches the tumor can be determined.

Performance during a strenuous swimming session is associated with high blood lactate: pyruvate ratio and hypoglycemia in fasted rats.

The aim of this study was to investigate the effect of lactatemia elevation and glycemia reduction on strenuous swimming performance in fasted rats. Three rats were placed in a swimming tank at the same time. The first rat was removed immediately (control group) and the remaining ones were submitted to a strenuous swimming session. After the second rat was exhausted (Exh group), the third one was immediately removed from the water (Exe group). According to the period of time required for exhaustion, the rats were divided into four groups: low performance (3–7 min), low-intermediary performance (8–12 min), high-intermediary performance (13–17 min), and high performance (18–22 min). All rats were removed from the swimming tanks and immediately killed by decapitation for blood collection or anesthetized for liver perfusion experiments. Blood glucose, lactate, and pyruvate concentrations, blood lactate/pyruvate ratio, and liver lactate uptake and its conversion to glucose were evaluated. Exhaustion in low and low-intermediary performance were better associated with higher lactate/pyruvate ratio. On the other hand, exhaustion in high-intermediary and high performance was better associated with hypoglycemia. Lactate uptake and glucose production from lactate in livers from the Exe and Exh groups were maintained. We concluded that there is a time sequence in the participation of lactate/pyruvate ratio and hypoglycemia in performance during an acute strenuous swimming section in fasted rats. The liver had an important participation in preventing hyperlactatemia and hypoglycemia during swimming through lactate uptake and its conversion to glucose.

Action of proanthocyanidin microdoses on pyruvate in blood

Action of proanthocyanidin microdoses on pyruvate in blood

Lactate/pyruvate monitoring during carotid endarterectomy under general anaesthesia versus cervical plexus block: A randomised controlled study.

Background and Aims:Carotid endarterectomy (CEA) reduces the risk of stroke in patients with significant carotid stenosis and may be performed under general anaesthesia (GA) or regional anaesthesia (RA). This study aimed to compare RA and GA with regard the jugular venous bulb blood lactate and pyruvate levels.Methods:This randomised-controlled trial was done between October-2013 and September-2015. Thirty-six patients were randomised into either GA or RA groups, with six excluded after randomisation. In the RA group, combined deep and superficial cervical plexus blocks were performed. In the GA group, anaesthesia was induced with propofol and fentanyl. In both groups, monitoring of neurological function was done. Sampling of the contralateral jugular bulb blood was done. The main outcome measures were lactate and pyruvate in the jugular venous blood. For comparing categorical data, Chi-square test was used, and for the numerical variables, t-test was used.Results:Demographics were comparable in the two Groups. Serum lactate and pyruvate levels were higher in the GA group than RA group. At 120 min under anaesthesia, lactate and pyruvate levels under RA vs. GA, respectively were 0.76±0.03 mEq/L vs. 1.14±0.06, p-0.001 mEq/L, and 0.08± 0.00 mEq/L vs. 0.10±0.01 mEq/L, p=0.006. Lactate/ pyruvate ratios were normal in both groups. The mean blood pressure was significantly lower in the GA group during anaesthesia.Conclusion:In patients undergoing Carotid endarterectomy, serum levels of both lactate and pyruvate were higher under general versus regional anaesthesia.

Disturbed fluid responsiveness and lactate/pyruvate ratio as predictors for mortality of septic shock patients

ObjectivesEvaluation of fluid responsiveness of septic shock patients admitted to surgical ICU and the predictability of non-invasive monitoring and estimated lactate/pyruvate (L/P) ratio for survival of these patients.Patients and methodsThe study included 58 septic shocked patients admitted and managed at surgical ICU. After non-invasive determination of baseline hemodynamic data and calculation of shock index (SI-0) and Pleth variability index (PVI-0), all patients received intravenous colloid infusion followed 15-min later by non-invasive re-evaluation for SI-15 and PVI-15. Blood samples were obtained for estimation of blood lactate and pyruvate levels at admission (BLL-0 and BPL-0) and 12-h after fluid resuscitation (BLL-12 and BPL-12) and L/P ratio was calculated. All patients were managed according to the Surviving Sepsis Campaign guidelines and followed up for ICU mortality rate (MR).ResultsICU stay MR was 20.7%. Survival showed negative significant correlation with PVI, L/P ratio and BLL, while it showed positive significant correlation with BPL. Receiver Operating Characteristic (ROC) curve analysis defined baseline and persistently low PVI, high BLL and L/P ratio as significant sensitive predictors for MR, while elevated BPL-12 as significant specific predictor for survival. Regression analysis defined persistently elevated L/P ratio as the highly significant specific predictor, while persistently disturbed SI and PVI could predict mortality as screening tests. Odds ratio for mortality at BLL-0 of >2 mmol/L was 0.0321 (95% CI: 0.0037–0.2755), while it was 4.1111 (95% CI: 1.0702–15.792) at BLL-0 >4 mmol/L.ConclusionAfter fluid resuscitation and hemodynamic stability, persistently elevated BLL could predict mortality, while elevated BPL could predict survival of septic shock patients. Continuous non-invasive evaluation of fluid responsiveness judged by PVI and SI could provide sensitive screening for survival outcome of shocked patients. Wider scale comparative studies are mandatory for establishment of discriminative PVI and BLL cutoff points for prediction of survival of shocked patients.

Rapid quantification of metabolic intermediates in blood by liquid chromatography-tandem mass spectrometry to investigate congenital lactic acidosis

A novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been established to quantify metabolic intermediates, including lactate (Lac), pyruvate (Pyr), acetoacetate (ACAC) and 3-hydroxybutyrate (3-HB) in blood. Samples were deproteinized with methanol-acetonitrile solution, and analytes were separated on an adamantyl group-bonded reverse phase column and detected in multiple reaction monitoring mode. Total analysis time was 4 min per sample. Method validation results displayed that limits of quantification were 10.0 μmol L−1 for Lac and Pyr, and 5.0 μmol L−1for ACAC and 3-HB. The within- and between-run coefficients of variation were in the range of 1.2–6.4% for all analytes. The recoveries were ranged from 95.6 to 111.5%. The reference values of analytes were determined for the pediatric population. Duo to instability of Lac, Pyr and ACAC in vitro, a comprehensive stability assay was performed to determine optimal conditions for sample collection, pretreatment and storage. Results showed that precipitation of protein in blood at bedside combined with low storage temperature could effectively preserve the integrity of Lac, Pyr and 3-HB, but the precipitated protein accelerated degradation of ACAC. Isolation of supernatant fluid slowed degradation of ACAC. Supernatant samples could store at −20 °C for 10 days. The use of plasma or serum to determine these intermediates was not recommended. In this study, 450 samples from patients were analyzed, and 7 patients were diagnosed as congenital lactic acidosis. With the advantages of rapid, accurate and reliable, this method is very suitable for congenital lactic acidosis screening and researches related to energy metabolism.

Abstract A56: A dual PI3K-mTOR inhibitor induced cardiac hypertrophy in mice: Role of the insulin signaling

Abstract Studies from us and others showed that mice with cardiomyocyte-specific overexpression of a dominant negative PI3Kp110α had smaller hearts but maintained normal cardiac function. Yet, these mice developed systolic heart failure in the presence of cardiac stress, such as chemotherapy drug doxorubicin and aortic stenosis. Currently, drugs targeting the PI3K pathway are being tested in clinical trials for cancer therapy. Therefore, it is important to assess the cardiac effects of pharmacological inhibition of this pathway. Here, we report that a dual PI3K-mTOR inhibitor, BEZ235 (BEZ), induced cardiac hypertrophy and subsequent heart failure in mice when it was used alone or in combination with doxorubicin. This effect of BEZ was associated with increased hepatic gluconeogenesis, hyperglycemia, hyperinsulinemia and increased activation of the IGFR/insulin receptor (IR) in the heart. In isolated cardiomyocyte culture, BEZ induced feedback activation of IGFR/IR, but this effect was negligible compared to the IGFR/IR activation in the presence of insulin. Injections of insulin in mice lowered blood glucose, improved glucose and pyruvate tolerance but further increased the activation of IGFR/IR in the heart and aggravated BEZ-induced cardiac dysfunction; whereas OSI-906, an IGFR/IR inhibitor, alleviated this cardiac dysfunction. In addition, low dose Metformin significantly prolonged survival and improved cardiac function in BEZ-treated mice. Taken together, these results identified hyperinsulinemia, a systematic effect of the drug, as one of the mechanisms of BEZ-induced cardiac hypertrophy, arguing animal studies are indispensable for evaluating drug toxicity. They also suggest that Metformin but not insulin should be considered for controlling hyperglycemia and preventing the cardiac side effects that may be caused by PI3K pathway inhibitors in clinic. Citation Format: Jillian Onufrak, Yongayo Yang, Juyong Lee, John Fuseler, Maoyun Sun, Sharath Sasi, J. Tyson McDonald, Lynn Hlatky, Robert L. Price, Joseph Carrozza, David Goukassian, Thomas K. Borg, James P. Morgan, Xinhua Yan. A dual PI3K-mTOR inhibitor induced cardiac hypertrophy in mice: Role of the insulin signaling. [abstract]. In: Proceedings of the AACR Special Conference: Targeting the PI3K-mTOR Network in Cancer; Sep 14-17, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(7 Suppl):Abstract nr A56.

P57 – 2330: An infant with later onset Aicardi-Goutieres syndrome caused by homozygous TREX1 gene mutation

Objective Aicardi-Goutieres syndrome (AGS) is both genetically and phenotypically heterogeneous disorder. Mutations in five genes – TREX1, RNASEH2B, RNASEH2C, RNASEH2A and SAMHD1 – are linked with AGS. Mutations in TREX1 are often associated with early onset neonatal AGS. This study was designed to describe clinical features and course of a child with later onset AGS associated with homozygous TREX1 mutation. Methods We present an infant with recurrent sterile fever and developmental regression. Results The patient was a girl, now 36 month of age, born to healthy consanguineous parents after an unremarkable pregnancy. She presented at 11 months of age with recurrent fever and motor regression. Family medical history was unremarkable and her development until the age of 8 months were uneventful. At this age, she started to lose acquired motor skills and had recurrent fever with 3 weeks interval. Although physical examination was normal, her head circumference 42 cm (P25). Neurological examination revealed hypotonia with brisk deep-tendon reflexes. Brain CT and MRI disclosed bilateral basal ganglia, and diffuse periventricular and subcortical white matter calcifications. Serological tests for congenital infections was negative. Complete blood count, serum lactate and pyruvate levels, aminoacid and organic acid screenings were normal. CSF examination showed no pleocytosis. Ophthalmic examination did not showed chorioretinis. The CSF concentration of IFN-a could not be assessed. Recurrent fever attack was investigated for infectious disease and autoinflammatory disorder. All results were unremarkable, and she was suspected as later onset AGS. AGS diagnosis was confirmed by DNA analyses which showed homozygous TREX1 exonuclease (p.Pro345-Ala350) gene mutation. During the follow-up, recurrent episodes of fever was spontaneously ceased. A period of mental and motor function regression followed by stabilization. Conclusion Although later onset AGS usually associated with RNaseH2B mutation. Here in, we present an interesting case with later onset AGS associated with homozygous TREX1 mutation.

Perturbed glucose metabolism: insights into multiple sclerosis pathogenesis.

Multiple sclerosis (MS) is a complex debilitating disease of the central nervous system (CNS) perceived to result from the autoimmune effect of T cells in damaging myelin sheath. However, the exact pathogenesis of the disease remains elusive. Initial studies describing the possibility of defective pyruvate metabolism in MS were performed in 1950s. The group observed elevated blood pyruvate level in both fasting and postprandial times in MS patients with relapse. Similarly, other investigators also reported increased fasting pyruvate level in this disease. These reports hint to a possible abnormality of pyruvate metabolism in MS patients. In addition, increase in levels of Krebs cycle acids like alpha-ketoglutarate in fasting and citrate after glucose intake in MS patients further strengthened the connection of disturbed pyruvate metabolism with MS progression. These studies led the investigators to explore the role of disturbed glucose metabolism in pathophysiological brain function. Under normal circumstances, complex molecules are metabolized into simpler molecules through their respective pathways. Differential expression of genes encoding enzymes of the glucose metabolic pathway in CNS may result in neurological deficits. In this review article, we discuss the studies related to disturbed carbohydrate metabolism in MS and other neurodegenerative diseases. These observations open new perspectives for the understanding of metabolic dynamics in MS yet many puzzling aspects and critical questions need to be addressed. Much more research is required to fully unravel the disease mechanism, and a proper understanding of the disease could eventually lead to new treatments.

Abstract 71: A Dual PI3K-mTOR Inhibitor Induced Hyperglycemia and Increased Insulin Signals in the Heart

We previously reported that a dual PI3K-mTOR inhibitor BEZ235 (BEZ) induced cardiac hypertrophy. Here, we investigated potential mechanisms. Methods: three month old FVB/n female mice were treated with BEZ for five weeks. Cardiac function was monitored by serial echocardiography during the treatment and hemodynamic measurements at the end of the study. Cell signaling was analyzed by RT-PCR, Western blotting and ELISA. Results: BEZ induced a dose-dependent increase of left ventricular (LV) wall thickness and systolic function. These were associated with increased hypertrophic markers ANP, BNP, β-MHC and α-skeletal actin in the heart. In addition, in chronic BEZ-treated mouse hearts, the activations of PI3Ks, mTOR and ERK were increased. We conducted further studies to understand these contradictory results. We found that BEZ induced an increase of hepatic gluconeogenesis gene expression which was associated with increased fasting glucose, increased serum insulin level, a worsened glucose and pyruvate tolerance and increased IGFR/Insulin receptor activation in the heart. Injections of insulin lowered blood glucose, improved glucose and pyruvate tolerance, but further aggravated BEZ-induced cardiac dysfunction. On the other hand, OSI-906 (an IGFR/IR inhibitor) normalized cardiac function in BEZ-treated mice. Conclusions: Chronic BEZ treatment induced cardiac hypertrophy may be caused by increased insulin receptor activation in the heart.

Single Sodium Pyruvate Ingestion Modifies Blood Acid-Base Status and Post-Exercise Lactate Concentration in Humans

This study examined the effect of a single sodium pyruvate ingestion on a blood acid-base status and exercise metabolism markers. Nine active, but non-specifically trained, male subjects participated in the double-blind, placebo-controlled, crossover study. One hour prior to the exercise, subjects ingested either 0.1 g·kg−1 of body mass of a sodium pyruvate or placebo. The capillary blood samples were obtained at rest, 60 min after ingestion, and then three and 15 min after completing the workout protocol to analyze acid-base status and lactate, pyruvate, alanine, glucose concentrations. The pulmonary gas exchange, minute ventilation and the heart rate were measured during the exercise at a constant power output, corresponding to ~90% O2max. The blood pH, bicarbonate and the base excess were significantly higher after sodium pyruvate ingestion than in the placebo trial. The blood lactate concentration was not different after the ingestion, but the post-exercise was significantly higher in the pyruvate trial (12.9 ± 0.9 mM) than in the placebo trial (10.6 ± 0.3 mM, p < 0.05) and remained elevated (nonsignificant) after 15 min of recovery. The blood pyruvate, alanine and glucose concentrations, as well as the overall pulmonary gas exchange during the exercise were not affected by the pyruvate ingestion. In conclusion, the sodium pyruvate ingestion one hour before workout modified the blood acid-base status and the lactate production during the exercise.

Aqueous Components of Tomato Accelerate Alcohol Metabolism by Increasing Pyruvate Level

Consumption of food while drinking alcohol has been suggested to play important roles in alleviating the physiological and pharmacological influences of alcohol. Vegetables are believed to provide health benefits, but there is little evidence for their influence on the effects of alcohol consumption. The present study aimed to investigate the effect of a common vegetable, tomato, on alcohol metabolism. In a randomized, controlled, crossover study with12 Japanese healthy men aged between 24 and 56 years, drinking tomato juice containing 5% (v/v) alcohol (TJAlc) significantly attenuated the elevation of blood ethanol level and subsequently increased the level of acetate compared with a water-based alcoholic beverage with an equal dose of alcohol (0.4 g/kg body weight). Significantly higher levels of blood pyruvate and lactate were also observed in subjects who had consumed TJAlc compared with those consuming the water-based beverage. Additionally, a biphasic alcohol effects scale method showed that subjective feelings for alcohol-induced stimulant effects were significantly enhanced by drinking TJAlc. Animal experiments using male Sprague Dawleyrats suggested that the effect on blood biomarkers was attributable to the serum fraction of tomato (TS), which largely consisted of aqueous compounds, but not lipophilic compounds such as the carotenoid lycopene. Furthermore, it was suggested the TS possibly included potent compound(s) in addition to alanine, glutamine, and citric acid, all of which have previously been reported to affect alcohol metabolism. Administration of TS clearly increased the activity of NAD (H)-dependent enzymes such as lactate-(LDH), alcohol-, and aldehyde-dehydrogenase in rat liver cytosols. These findings suggest that aqueous compound(s) in tomato promote alcohol metabolism, probably through increasing pyruvate level, enhancing LDH activity, and improving the ratio of NAD to NADH.

Lactate and Pyruvate Levels in Blood and Cerebrospinal Fluid in Patients with Menkes Disease

To examine levels of lactate (LA) and pyruvate (PA) in both blood and cerebrospinal fluid (CSF) in patients with Menkes disease (MNK). A nationwide survey involving a retrospective review of medical records or medical record summaries of 42 male patients with MNK born between 1993 and 2008 were performed, and the genetic analysis of their ATP7A gene was reviewed. In these patients, LA and PA levels and the lactate vs pyruvate ratio (L/P ratio) at diagnosis in both blood and CSF were abnormally high. There were no significant differences in LA levels, PA levels, and the L/P ratio between blood and CSF at diagnosis (P > .05). There was also no correlation between LA levels, PA levels, and the L/P ratio, and age at measurement (P > .05). There was no or slight metabolic acidosis, as analyzed by blood gas analysis, in 7 patients. During treatment with subcutaneous injections of copper-histidine, LA and PA levels and the L/P ratio in both the blood and CSF decreased. Our findings suggest that LA and PA levels, and in particular, the L/P ratio, and blood gas analysis can be used to guide the diagnosis and management of MNK.

Mitochondrial Dysfunction in Autism

Using data of the current prevalence of autism as 200:10,000 and a 1:2000 incidence of definite mitochondrial (mt) disease, if there was no linkage of autism spectrum disorder (ASD) and mt disease, it would be expected that 1 in 110 subjects with mt disease would have ASD and 1 in 2000 individuals with ASD would have mt disease. The co-occurrence of autism and mt disease is much higher than these figures, suggesting a possible pathogenetic relationship. Such hypothesis was initially suggested by the presence of biochemical markers of abnormal mt metabolic function in patients with ASD, including elevation of lactate, pyruvate, or alanine levels in blood, cerebrospinal fluid, or brain; carnitine level in plasma; and level of organic acids in urine, and by demonstrating impaired mt fatty acid β-oxidation. More recently, mtDNA genetic mutations or deletions or mutations of nuclear genes regulating mt function have been associated with ASD in patients or in neuropathologic studies on the brains of patients with autism. In addition, the presence of dysfunction of the complexes of the mt respiratory chain or electron transport chain, indicating abnormal oxidative phosphorylation, has been reported in patients with ASD and in the autopsy samples of brains. Possible pathogenetic mechanisms linking mt dysfunction and ASD include mt activation of the immune system, abnormal mt Ca(2+) handling, and mt-induced oxidative stress. Genetic and epigenetic regulation of brain development may also be disrupted by mt dysfunction, including mt-induced oxidative stress. The role of the purinergic system linking mt dysfunction and ASD is currently under investigation. In summary, there is genetic and biochemical evidence for a mitochondria (mt) role in the pathogenesis of ASD in a subset of children. To determine the prevalence and type of genetic and biochemical mt defects in ASD, there is a need for further research using the latest genetic technology such as next-generation sequencing, microarrays, bioinformatics, and biochemical assays. Because of the availability of potential therapeutic options for mt disease, successful research results could translate into better treatment and outcome for patients with mt-associated ASD. This requires a high index of suspicion of mt disease in children with autism who are diagnosed early.

Elevated plasma citrulline: look for dihydrolipoamide dehydrogenase deficiency

The E3 subunit of the pyruvate dehydrogenase complex (dihydrolipoamide dehydrogenase/dihydrolipoyl dehydrogenase/DLD/lipoamide dehydrogenase/LAD), is a mitochondrial matrix enzyme and also a part of the branched-chain ketoacid dehydrogenase and alpha-ketoglutarate dehydrogenase complexes. DLD deficiency (MIM #246900), is relatively frequent in the Ashkenazi Jewish population but occurs in other populations as well. Early diagnosis is important to prevent episodes of metabolic decompensation, liver failure, and encephalopathy. The clinical presentations are varied and may include Reye-like syndrome, hepatic failure, myopathy, and myoglobinuria. Laboratory markers, such as elevated urinary alpha-ketoglutarate, blood pyruvate, lactate, and ammonia, are mostly nonspecific and not always present, making the diagnosis difficult. Since we observed elevated plasma citrulline levels in a number of confirmed cases, we retrospectively examined the value of citrulline as a biochemical marker for DLD deficiency. Data was gathered from the files of 17 pediatric patients with DLD deficiency, confirmed by enzymatic and genetic analysis. The control group included 19 patients in whom urea cycle defects were ruled out but DLD deficiency was suspected. Seven of the DLD-deficient patients presented with elevated plasma citrulline levels (median value 205μM, range 59-282μM) (normal range 1-45μM) while none in the control patient group. In five patients, elevated citrulline was associated with elevated plasma glutamine and metabolic acidosis. Interestingly, elevated plasma citrulline was associated with the common G229C mutation. In conclusion, we suggest that elevated plasma citrulline in the absence of urea cycle defects warrants an investigation for DLD deficiency.

Hyperpolarized singlet lifetimes of pyruvate in human blood and in the mouse

Hyperpolarized NMR is a promising technique for non-invasive imaging of tissue metabolism in vivo. However, the pathways that can be studied are limited by the fast T1 decay of the nuclear spin order. In metabolites containing pairs of coupled nuclear spins-1/2, the spin order may be maintained by exploiting the non-magnetic singlet (spin-0) state of the pair. This may allow preservation of the hyperpolarization in vivo during transport to tissues of interest, such as tumors, or to detect slower metabolic reactions. We show here that in human blood and in a mouse in vivo at millitesla fields the 13C singlet lifetime of [1,2-13C2]pyruvate was significantly longer than the 13C T1, although it was shorter than the T1 at field strengths of several tesla. We also examine the singlet-derived NMR spectrum observed for hyperpolarized [1,2-13C2]lactate, originating from the metabolism of [1,2-13C2]pyruvate. © 2013 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd.