Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Regulation of the pyruvate dehydrogenase (PDH) complex has been demonstrated to be a key mechanism in the control of carbohydrate oxidation and conservation of glucose carbon. The effect of sterile inflammation and chronic sepsis (small and large abscess) on the activity of the PDH complex was examined in liver and skeletal muscle. Sepsis altered the proportion of PDH in the active, dephosphorylated form. In hepatic tissue, sterile inflammation leads to a 2.5-fold increase in the proportion of active PDH complex compared to fed control. The same increase in the proportion of active PDH complex was observed in rats with a small septic abscess. However, when the severity of septic episode was increased, the proportion of active PDH complex decreased relative to sterile inflammation or small septic abscess animals. A different pattern in the response to sterile inflammation and sepsis on the proportion of active PDH complex was observed in skeletal muscle compared to liver. In contrast to liver, sterile inflammation did not alter the proportion of active PDH in skeletal muscle. In addition, sepsis (either small or large septic abscess) resulted in a 3-fold decrease in the proportion of active PDH relative to fed control or sterile inflammatory animals. The decrease in the proportion of active PDH complex in sepsis was associated with a corresponding increase in the skeletal muscle acetyl-CoA/CoA ratio. The mechanism responsible for lowered PDH complex activity may have been due to increased PDH kinase activity, secondary to increased skeletal muscle acetyl-CoA/CoA ratios.
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PMID:Regulation of glucose metabolism by altered pyruvate dehydrogenase activity. I. Potential site of insulin resistance in sepsis. 352 46

A male infant had severe muscular hypotonia from birth. Recurrent vomiting with dehydration and severe metabolic acidosis complicated the course. Elevated lactate (up to 12.3 mmol/l; n less than 2), pyruvate (0.4 mmol/l; n less than 0.05) and alanine levels were found in serum with an abnormal lactate/pyruvate ratio (greater than 30; n less than 15). In urine the concentrations of lactate, pyruvate, alanine and of several intermediates of the citric acid cycle were increased. In muscle, numerous disseminated "ragged red fibres" were found by light microscopy; muscle fibres were found to contain subsarcolemmal aggregates of mitochondria, lipid droplets and glycogen by electromicroscopical methods. Moreover, mitochondria with a typical circular arrangement of cristae were noticed. In liver homogenates normal activities of pyruvate carboxylase and pyruvate dehydrogenase complex were found; in liver mitochondria also succinate-cytochrome-c-oxidoreductase activity was normal. However, in muscle no succinate-cytochrome-c-oxidoreductase activity was detectable. The patient became increasingly lethargic and died because of sepsis at 5 months of age.
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PMID:Mitochondrial myopathy with lactic acidosis and deficient activity of muscle succinate cytochrome-c-oxidoreductase. 609 51

The effect of inflammation and chronic sepsis on the activity of pyruvate dehydrogenase complex (PDH) in skeletal muscle was investigated in rats. Inflammation was induced by the placement of a catheter in the carotid artery. Sepsis was induced by repeated (every 48 hr) injections of an inoculum composed of Staphylococcus aureus, Escherichia coli, and Bacteroides fragilis organisms into a preformed subcutaneous abscess. Hindlimb muscle was sampled 7 or 14 days following the initial injection of the inoculum into the abscess. Total PHD activity was not altered by any of the conditions examined. There were no differences in the proportion of active PDH complex after 7 days in any of the conditions examined. In contrast, 14 days after the initial bacterial injection, the concentration of active PDH complex in skeletal muscle was reduced by 50% in the septic rats. The combination of intravascular catheterization and infection resulted in a further decrease in the concentration of active PDH complex. The decreased concentration of active PDH complex was associated with increased plasma lactate concentrations in septic rats. Catheterization exacerbated the rise in plasma lactate in sepsis. In this model of chronic sepsis, the magnitude of the hyperlactatemia and the inhibition of the PDH complex in skeletal muscle appear dependent upon the length of time of the septic insult and are potentiated by addition of an intravascular focus of inflammation.
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PMID:Potentiation of decreased pyruvate dehydrogenase activity by inflammatory stimuli in sepsis. 848 21

A decreased proportion of active pyruvate dehydrogenase complex (PDH) in skeletal muscle has been implicated as an important factor in elevating plasma lactate concentrations in hypermetabolic sepsis. The mediators of the septic process responsible for the inhibition of PDH complex in muscle are unknown. To assess the role of tumor necrosis factor in mediating the effects of sepsis, the effect of daily injections of amrinone (5 mg/kg/day), which inhibits the release of tumor necrosis factor during sepsis, on the proportion of PDH in the active form (PDHa) was investigated in a model of chronic hypermetabolic sepsis. In skeletal muscle from untreated septic rats, PDHa was decreased 50%. Treatment of septic rats with amrinone for 5 days prevented the sepsis-induced decrease in PDHa. Sepsis caused a 2.5-fold elevation in plasma lactate concentrations. The maintenance of the PDH complex activity at control values following injection of amrinone in septic rats was associated with reduced lactate concentrations in plasma. Thus, amrinone prevented the sepsis-induced abnormalities in skeletal muscle PDH activity and plasma lactate concentrations.
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PMID:Amrinone prevents the inhibition of muscle pyruvate dehydrogenase complex activity during sepsis. 869 89

The pyruvate dehydrogenase (PDH) complex undergoes reversible phosphorylation catalyzed by a PDH kinase (inactivating) and a PDH phosphatase (activating). In skeletal muscle, a decreased proportion of PDH complex in the active, nonphosphorylated form (PDHa) limits glucose oxidation and promotes the conversion of pyruvate to lactate. Increased lactate formation with the accompanying hyperlactatemia is a frequent metabolic complication of sepsis. The time course for inactivation of the PDH complex in skeletal muscle during sepsis was contrasted with changes in PDHa during sterile inflammation 3,7, or 14 days following the implantation of the foreign body nidus. Total PDH complex activity was not altered in any of the conditions examined. Sepsis, but not sterile inflammation, caused a reduction in the muscle PDHa measured 3 or 7 days following induction of sepsis. The inhibition of the muscle PDHa during sepsis was associated with a sustained hyperlactatemia. PDH kinase activity measured in extracts of mitochondria was enhanced twofold during this period. Fourteen days after induction of sepsis, there were no differences in the PDHa or plasma lactate concentrations in septic rats compared with either control or sterile inflammation. Furthermore, the PDH kinase activity was decreased to values observed in control values. The results are consistent with the hypothesis that a reduced PDHa in skeletal muscle during sepsis is responsible, in part, for the hyperlactatemia characteristic of septic hypermetabolism. Furthermore, the results provide evidence that the decrease in PDHa results from a stable stimulation of PDH kinase activity.
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PMID:Sepsis-induced alterations in pyruvate dehydrogenase complex activity in rat skeletal muscle: effects on plasma lactate. 885 41

Energy substrate metabolism during stress is characterized by increased REE (resting energy expenditure), hyperglycemia, hyperlactatemia and protein catabolism. This stress-induced hypermetabolic responses are closely related to increased secretion of neurohormonal and cytokine mediators. The insulin resistance hyperglycemia has been called "stress diabetes" or "surgical diabetes". Glucose disposal has been thought to be impaired in this condition. However, glucose uptake in most tissue is non-insulin mediated. Recent studies showed glucose uptake elevated in sepsis or TNF infusion. Insulin-regulatable glucose transporter (GLUT4) is present only in muscle, heart and adipose tissues. It was demonstrated that insulin binding to membrane receptors in these tissues was intact. This hyperglycemia in stress diabetes results from a postreceptor mechanism. Stress hyperlactatemia is thought to be caused by decreased pyruvate dehydrogenase activity rather than tissue hypoperfusion. Hyperlactatemia may promote gluconeogenesis. Glucose is a essential energy substrate in some tissues such as brain, erythrocyte and leukocyte. Hyperglycemia may be viewed as a beneficial response during stress.
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PMID:[Energy substrate metabolism during stress]. 894 Jun 83

Cardiodepressant effects of tumor necrosis factor-alpha (TNF-alpha have been documented in numerous experimental settings in vivo and in vitro. In vivo administration of TNF-alpha mimicks the cardiovascular pattern of sepsis including septic cardiomyopathy. Serum levels of TNF-alpha were found to be elevated both in sepsis and in numerous non-septic heart disorders. Although an involvement of TNF-alpha in the pathogenesis of septic cardiomyopathy seems likely, presently no definite conclusion can be drawn with regard to the role of TNF-alpha in chronic heart failure. The origin and trigger mechanisms for the release of TNF-alpha in heart failure are a matter of debate, endotoxin (LPS) from intestinal translocation in venous congestion being one possible player. The negative inotropic impact of TNF-alpha is frequently ascribed to the induction of inducible nitric oxide (NO) synthase (iNOS). Results from in vitro studies rather suggest a complex interaction of TNF-alpha with the heart, with pleiotropic effects on cardiomyocyte performance, including an induction of iNOS at higher TNF-alpha concentrations, but NO-independent cardiodepression at low, pathophysiologically more relevant concentrations. TNF-alpha effects on the heart also vary with regard to the kinetics of the process: rapidly occuring cardiodepressant effects include a release of sphingosine and a suppression of the calcium transient, while chronic administration of TNF-alpha was shown to depress the synthesis of precursors for the phosphoinositide pathway and inhibit pyruvate dehydrogenase activity and mitochondrial function. Whether secondary cytokines induced by TNF-alpha in cardiomyocytes contribute to cardiodepression or whether apoptotic signals activated by TNF-alpha are involved in the cardiodepressive pathways is presently unknown.
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PMID:Cardiodepression by tumor necrosis factor-alpha. 988 17

Chronic sepsis promotes a stable increase in pyruvate dehydrogenase kinase (PDHK) activity in skeletal muscle. PDHK is found tightly bound to the pyruvate dehydrogenase (PDH) complex and as free kinase. We investigated the ability of sepsis to modify the activity of the PDHK intrinsic to the PDH and free PDHK. Sepsis was induced by the intraabdominal introduction of a fecal-agar pellet infected with E. coli and B. fragilis. Five days later, mitochondria were isolated from skeletal muscle and PDHK measured in mitochondrial extracts. Sepsis caused an approximate 2-fold stimulation of PDHK. The mitochondrial extracts from control and septic rats were fractionated by gel chromatography on Sephacryl S-300 to separate PDHK intrinsic to PDH complex and free PDHK. PDH complex eluted at void volume and was assayed for PDHK intrinsic to the complex. The activity of PDHK intrinsic to PDH complex was a significantly increased 3 fold during sepsis. Free PDHK activity eluted after the PDH complex and its activity was enhanced by 70% during sepsis. Incubation of PDHK intrinsic to PDH with dichloroactate, an uncompetitive inhibitor of PDHK, showed the PDHK from septic rats relatively less sensitive to inhibition than controls. These results indicate that sepsis induces stable changes in PDHK in skeletal muscle.
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PMID:Sepsis alters pyruvate dehydrogenase kinase activity in skeletal muscle. 1049 85

Altered pyruvate dehydrogenase (PDH) functioning occurs in primary PDH deficiencies and in diabetes, starvation, sepsis, and possibly Alzheimer's disease. Currently, the activity of the enzyme complex is difficult to measure in a rapid high-throughput format. Here we describe the use of a monoclonal antibody raised against the E2 subunit to immunocapture the intact PDH complex still active when bound to 96-well plates. Enzyme turnover was measured by following NADH production spectrophotometrically or by a fluorescence assay on mitochondrial protein preparations in the range of 0.4 to 5.0 micro g per well. Activity is sensitive to known PDH inhibitors and remains regulated by phosphorylation and dephosphorylation after immunopurification because of the presence of bound PDH kinase(s) and phosphatase(s). It is shown that the immunocapture assay can be used to detect PDH deficiency in cell extracts of cultured fibroblasts from patients, making it useful in patient screens, as well as in the high-throughput format for discovery of new modulators of PDH functioning.
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PMID:Immunocapture and microplate-based activity measurement of mammalian pyruvate dehydrogenase complex. 1263 10

Energy-metabolism disturbances during sepsis are characterized by enhanced glycolytic fluxes and reduced mitochondrial respiration. However, it is not known whether these abnormalities are the result of a specific mitochondrial alteration, decreased pyruvate dehydrogenase (PDH) complex activity, depletion of ubiquinone (CoQ(10); electron donor for the mitochondrial complex III), or all 3. In this study we sought to specify metabolism disturbances in a murine model of sepsis, using either a PDH-activator infusion (dichloroacetate, DCA) or CoQ(10) supplementation. After anesthesia, Sprague-Dawley rats received intravenous saline solution (control; n = 5), DCA (n = 5; 20 mg/100 g), or CoQ(10) (n = 5; 1 mg/100 g), before the induction of sepsis. Increased plasma lactate levels and increased muscle glucose content were observed after 4 hours in the control group. In the DCA group, a decrease in the muscle content of lactate (P <.05) and an increase in muscle glucose content (P <.05) were observed at 4 hours, but no lactatemia variation was noted. In the CoQ(10) group, only increased plasma lactate levels were observed. Increased muscle glycolysis fluxes were observed after 4 hours in the control group, but to a slighter degree in both the DCA and CoQ(10) groups. Only DCA restored a normal temperature sensitivity in the hyperthermia range, but we noted no differences in survival time. In conclusion, only DCA infusion restores normal glycolysis function.
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PMID:Effects of dichloroacetate and ubiquinone infusions on glycolysis activity and thermal sensitivity during sepsis. 1519 51


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