The pyruvate dehydrogenase complex (PDC) is an emerging target for the treatment of metabolic syndrome. To maintain a steady-state concentration of adenosine triphosphate during the feed-fast cycle, cells require efficient utilization of fatty acid and glucose, which is controlled by the PDC. The PDC converts pyruvate, coenzyme A (CoA), and oxidized nicotinamide adenine dinucleotide (NAD+) into acetyl-CoA, reduced form of nicotinamide adenine dinucleotide (NADH), and carbon dioxide. The activity of the PDC is up- and down-regulated by pyruvate dehydrogenase kinase and pyruvate dehydrogenase phosphatase, respectively. In addition, pyruvate is a key intermediate of glucose oxidation and an important precursor for the synthesis of glucose, glycerol, fatty acids, and nonessential amino acids.
Acetyl Coenzyme A ; Adenosine Triphosphate ; Amino Acids ; Carbon Dioxide ; Coenzyme A ; Diabetes Mellitus ; Fatty Acids ; Glucose ; Glycerol ; NAD ; Obesity* ; Oxidoreductases* ; Phosphotransferases* ; Pyruvate Dehydrogenase (Lipoamide)-Phosphatase ; Pyruvate Dehydrogenase Complex ; Pyruvic Acid*

OBJECTIVETo analyze the clinical characteristics and genetype of one children who had been diagnosed with pyruvate dehydrogenase complex deficiency.

METHODComprehensive analyses of this case were performed, including clinical symptoms, signs, biochemical examinations and therapeutic effects. The eleven exons and splicing areas of PDHA1 were amplified with genomic DNA from whole blood. And variations were investigated by sequencing the PCR product. The patient was diagnosed with pyruvate dehydrogenase complex deficiency by sequence analysis of PDHA1 gene.

RESULTThe patient was a 2 years and 4 monthes old boy. He presented with muscle hypotonia and weakness for one year, and experienced recurrent episodes of unstable head control, unable to sit by himself or stand without support, with persistently hyperlactacidemia. Metabolic testing revealed blood lactate 5.37 mmol/L, pyruvate 0.44 mmol/L, and lactate/pyruvate ratio was 12.23. MRI of the brain showed hyperintense signals on the T2 and T2 Flair weighted images in the basal ganglia bilaterally. Sequence analysis of PDHA1 gene showed a G>A point mutation at nucleotide 778, resulting in a substitution of glutarnine for arginine at position 263 (R263Q). And the diagnosis of pyruvate dehydrogenase complex deficiency was identified. By giving the therapy with ketogenic diet, vitamin B(1), coenzyme Q(10) and L-carnitine , the boy was in a stable condition.

CONCLUSIONThe severity and the clinical phenotypes of pyruvate dehydrogenase complex deficiency varied. Sequence analysis of PDHA1 gene revealed a 788G>A (R263Q) mutation. Patients who presented with unexplained muscle hypotonia, weakness and hyperlactacidemia could be diveded by gene analysis. And appropriate treatment can improve the quality of life.

Brain ; Carnitine ; Child, Preschool ; Exons ; genetics ; Humans ; Magnetic Resonance Imaging ; Male ; Mutation ; Phenotype ; Pyruvate Dehydrogenase (Lipoamide) ; genetics ; Pyruvate Dehydrogenase Complex Deficiency Disease ; diagnosis ; genetics ; Pyruvic Acid

High extracellular glucose concentration was reported to suppress intracellular Ca2+ clearing through altered sarcoplasmic reticulum (SR) function. In the present study, we attempted to elucidate the effects of pyruvate and fatty acid on SR function and reveal the mechanistic link with glucose-induced SR dysfunction. For this purpose, SR Ca2+-uptake rate was measured in digitonin-permeabilized H9c2 cardiomyocytes cultured in various conditions. Exposure of these cells to 5 mM pyruvate for 2 days induced a significant suppression of SR Ca2+-uptake, which was comparable to the effects of high glucose. These effects were accompanied with decreased glucose utilization. However, pyruvate could not further suppress SR Ca2+-uptake in cells cultured in high glucose condition. Enhanced entry of pyruvate into mitochondria by dichloroacetate, an activator of pyruvate dehydrogenase complex, also induced suppression of SR Ca2+-uptake, indicating that mitochondrial uptake of pyruvate is required in the SR dysfunction induced by pyruvate or glucose. On the other hand, augmentation of fatty acid supply by adding 0.2 to 0.8 mM oleic acid resulted in a dose-dependent suppression of SR Ca2+-uptake. However, these effects were attenuated in high glucose-cultured cells, with no significant changes by oleic acid concentrations lower than 0.4 mM. These results demonstrate that (1) increased pyruvate oxidation is the key mechanism in the SR dysfunction observed in high glucose-cultured cardiomyocytes; (2) exogenous fatty acid also suppresses SR Ca2+-uptake, presumably through a mechanism shared by glucose.
Diabetic Cardiomyopathies* ; Dichloroacetic Acid ; Glucose ; Hand ; Mitochondria ; Myocytes, Cardiac* ; Oleic Acid ; Pyruvate Dehydrogenase Complex ; Pyruvic Acid* ; Sarcoplasmic Reticulum*

Mitochondrial dysfunction represents a biochemically and clinically diverse group of conditions that can affect any organs with high energy requirement such as brain and muscle being particularly vulnerable. Pyruvate dehydrogenase complex (PDHC) deficiency is one type of mitochondrial dysfuntion that is anesthetically associated with lactic acidosis, muscle hypotonia, malignant hyperthermia, and postoperative respiratory failure. We report a case of general anesthetic management during ventriculoperitoneal shunt in a pediatric patient with PDHC deficiency and its possible considerations.
Acidosis, Lactic ; Brain ; Humans ; Malignant Hyperthermia ; Muscle Hypotonia ; Muscles ; Pyruvate Dehydrogenase Complex ; Pyruvic Acid ; Respiratory Insufficiency ; Ventriculoperitoneal Shunt

Mitochondrial dysfunction represents a biochemically and clinically diverse group of conditions that can affect any organs with high energy requirement such as brain and muscle being particularly vulnerable. Pyruvate dehydrogenase complex (PDHC) deficiency is one type of mitochondrial dysfuntion that is anesthetically associated with lactic acidosis, muscle hypotonia, malignant hyperthermia, and postoperative respiratory failure. We report a case of general anesthetic management during ventriculoperitoneal shunt in a pediatric patient with PDHC deficiency and its possible considerations.
Acidosis, Lactic ; Brain ; Humans ; Malignant Hyperthermia ; Muscle Hypotonia ; Muscles ; Pyruvate Dehydrogenase Complex ; Pyruvic Acid ; Respiratory Insufficiency ; Ventriculoperitoneal Shunt

Mitochondria are crucial for maintaining the properties of embryonic stem cells (ESCs) and for regulating their subsequent differentiation into diverse cell lineages, including cardiomyocytes. However, mitochondrial regulators that manage the rate of differentiation or cell fate have been rarely identified. This study aimed to determine the potential mitochondrial factor that controls the differentiation of ESCs into cardiac myocytes. We induced cardiomyocyte differentiation from mouse ESCs (mESCs) and performed microarray assays to assess messenger RNA (mRNA) expression changes at differentiation day 8 (D8) compared with undifferentiated mESCs (D0). Among the differentially expressed genes, Pdp1 expression was significantly decreased (27-fold) on D8 compared to D0, which was accompanied by suppressed mitochondrial indices, including ATP levels, membrane potential, ROS and mitochondrial Ca²⁺. Notably, Pdp1 overexpression significantly enhanced the mitochondrial indices and pyruvate dehydrogenase activity and reduced the expression of cardiac differentiation marker mRNA and the cardiac differentiation rate compared to a mock control. In confirmation of this, a knockdown of the Pdp1 gene promoted the expression of cardiac differentiation marker mRNA and the cardiac differentiation rate. In conclusion, our results suggest that mitochondrial PDP1 is a potential regulator that controls cardiac differentiation at an early differentiation stage in ESCs.
Adenosine Triphosphate ; Animals ; Cell Lineage ; Embryonic Stem Cells ; Membrane Potentials ; Mice* ; Mitochondria ; Mouse Embryonic Stem Cells* ; Myocytes, Cardiac* ; Oxidoreductases ; Pyruvate Dehydrogenase (Lipoamide)-Phosphatase* ; Pyruvic Acid* ; RNA, Messenger

In the well-fed state a relatively high activity of the pyruvate dehydrogenase complex (PDC) reduces blood glucose levels by directing the carbon of pyruvate into the citric acid cycle. In the fasted state a relatively low activity of the PDC helps maintain blood glucose levels by conserving pyruvate and other three carbon compounds for gluconeogenesis. The relative activities of the pyruvate dehydrogenase kinases (PDKs) and the opposing pyruvate dehydrogenase phosphatases determine the activity of PDC in the fed and fasted states. Up regulation of PDK4 is largely responsible for inactivation of PDC in the fasted state. PDK4 knockout mice have lower fasting blood glucose levels than wild type mice, proving that up regulation of PDK4 is important for normal glucose homeostasis. In type 2 diabetes, up regulation of PDK4 also inactivates PDC, which promotes gluconeogenesis and thereby contributes to the hyperglycemia characteristic of this disease. When fed a high fat diet, wild type mice develop fasting hyperglycemia but PDK4 knockout mice remain euglycemic, proving that up regulation of PDK4 contributes to hyperglycemia in diabetes. These finding suggest PDK4 inhibitors might prove useful in the treatment of type 2 diabetes.
Animals ; Blood Glucose ; Carbon ; Citric Acid Cycle ; Diet, High-Fat ; Fasting ; Gluconeogenesis ; Glucose ; Homeostasis ; Hyperglycemia ; Ketone Bodies ; Mice ; Mice, Knockout ; Oxidoreductases ; Phosphoric Monoester Hydrolases ; Phosphotransferases ; Protein Kinases ; Protein-Serine-Threonine Kinases ; Pyruvate Dehydrogenase Complex ; Pyruvic Acid ; Up-Regulation

PURPOSE: The aim of our study was to explore the relationships between the M2 isoform of pyruvate kinase (PKM2) and the sensitivity of human non-small cell lung cancer (NSCLC) cells to docetaxel in vitro. MATERIALS AND METHODS: With the method of plasmid transfection, we silenced the expression of PKM2 successfully in A549 and H460 cells. Western blotting and real-time PCR were applied to detect PKM2 expression at protein and gene levels. Cell viability was examined by CCK8 assay. Cell cycle distribution and apoptosis were examined by flow cytometry. P21 and Bax were detected. RESULTS: Expression of PKM2 mRNA and protein were significantly decreased by shRNA targeting PKM2. Silencing of PKM2 increased docetaxel sensitivity of human NSCLC A549 and H460 cells in a collaborative manner, resulting in strong suppression of cell viability. The results of flow cytometric assays suggested that knockdown of PKM2 or docetaxel treatment, whether used singly or in combination, blocked the cells in the G2/M phase, which is in consistent with the effect of the two on the expression of p21. Cells with PKM2 silencing were more likely to be induced into apoptosis by docetaxel although knockdown of PKM2 alone can't induce apoptosis significantly, which is in consistent with the effect of the two on Bax expression. CONCLUSION: The results suggest that PKM2 knockdown could serve as a chemosensitizer to docetaxel in non-small lung cancer cells through targeting PKM2, leading to inhibition of cell viability, increase of cell arrest of G2/M phase and apoptosis.
Apoptosis ; Blotting, Western ; Carcinoma, Non-Small-Cell Lung ; Cell Cycle ; Cell Line* ; Cell Survival ; Drug Therapy ; Flow Cytometry ; Humans* ; In Vitro Techniques* ; Lung Neoplasms ; Methods ; Plasmids ; Pyruvate Kinase* ; Pyruvic Acid* ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; RNA, Small Interfering* ; Transfection

Impaired glucose homeostasis is one of the risk factors for causing metabolic diseases including obesity, type 2 diabetes, and cancers. In glucose metabolism, pyruvate dehydrogenase complex (PDC) mediates a major regulatory step, an irreversible reaction of oxidative decarboxylation of pyruvate to acetyl-CoA. Tight control of PDC is critical because it plays a key role in glucose disposal. PDC activity is tightly regulated using phosphorylation by pyruvate dehydrogenase kinases (PDK1 to 4) and pyruvate dehydrogenase phosphatases (PDP1 and 2). PDKs and PDPs exhibit unique tissue expression patterns, kinetic properties, and sensitivities to regulatory molecules. During the last decades, the up-regulation of PDKs has been observed in the tissues of patients and mammals with metabolic diseases, which suggests that the inhibition of these kinases may have beneficial effects for treating metabolic diseases. This review summarizes the recent advances in the role of specific PDK isoenzymes on the induction of metabolic diseases and describes the effects of PDK inhibition on the prevention of metabolic diseases using pharmacological inhibitors. Based on these reports, PDK isoenzymes are strong therapeutic targets for preventing and treating metabolic diseases.
Acetyl Coenzyme A ; Decarboxylation ; Diabetes Mellitus, Type 2 ; Glucose ; Homeostasis ; Humans ; Isoenzymes ; Mammals ; Metabolic Diseases ; Metabolism ; Obesity ; Oxidoreductases* ; Phosphoric Monoester Hydrolases ; Phosphorylation ; Phosphotransferases* ; Pyruvate Dehydrogenase Complex ; Pyruvic Acid* ; Risk Factors ; Up-Regulation

To compare the influence of the Bach Mai prepared AS-T preserving solution and Japanese Turumo firm prepared preserving solution in a same condition on the blood of 5 healthy persons of B group blood, who did not donate the blood. AS-T solution had stabilized and maintained the red blood cells, pH higher than 7 through a storage duration of 42 days. AS-T solution had maintained 2.3-DPG concentration in a level higher significantly in comparing with Terumo solution at the terminal points of the storage time PK and G6PD activities of the red blood cells mass preserved by AS-T solution as well as Terumo solution had decreased progressively in the duration of storage.
Erythrocytes ; 2,3-Diphosphoglycerate ; Pyruvate Kinase