flavin-adenine-dinucleotide and Diabetes-Mellitus

Topics: Animals; Diabetes Mellitus; Electron Transport; Female; Flavin-Adenine Dinucleotide; Glucose; Humans; Hydrolases; Hyperinsulinism; Hyperthyroidism; Insulin; Insulin Secretion; Islets of Langerhans; Kynurenine; Membranes; Mitochondria, Liver; Mixed Function Oxygenases; Pregnancy; Quinaldines; Rats; Streptozocin; Thyroxine; Transaminases

Continuous glucose monitoring (CGM) systems are most important in the current Type I diabetes care and as component for the development of artificial pancreas systems because the amount of insulin being supplied is calculated based on the CGM results. Therefore, to stably and accurately control the blood glucose level, CGM should be stable and accurate for a long period. We have been engaged in the biomolecular engineering and application of FAD dependent glucose dehydrogenase complex (FADGDH) which is capable of direct electron transfer. In this study, we report the development of the third-generation type open circuit potential (OCP) principle-based glucose sensor with direct electron transfer FADGDH immobilized on gold electrodes using a self-assembled monolayer (SAM). We developed a novel algorithm for OCP-based glucose sensors. By employing this new algorithm, high reproducibility of measurement and sensor preparation were achieved. In addition, the signal was not affected by the presence of acetaminophen and ascorbic acid in the sample solution. The thus optimized third-generation OCP-based glucose sensor could be operated continuously for more than 9 days without significant change in the signal, sensitivity and dynamic range, indicating its potential application for CGM systems.

Topics: Biosensing Techniques; Blood Glucose; Blood Glucose Self-Monitoring; Diabetes Mellitus; Flavin-Adenine Dinucleotide; Glucose; Glucose 1-Dehydrogenase; Humans; Insulin

Diabetes devastates lives and burdens society. Hypoglycemic (low glucose) episodes cause blackouts, and severe ones are life-threatening. Periods of hyperglycemia (high glucose) cause circulatory disease, stroke, amputations, blindness, kidney failure and nerve degeneration. In this Account, we describe the founding of TheraSense, now a major part of Abbott Diabetes Care, and the development of two products that have improved the lives of people with diabetes. The first, a virtually painless microcoulometer (300 nL volume), the FreeStyle blood glucose monitoring system, was approved by the FDA and became available in 2000. In 2009, this system was used in more than one billion blood assays. The second, the enzyme-wiring based, subcutaneously-implanted FreeStyle Navigator continuous glucose monitoring system, was approved by the FDA and became available in the United States in 2008. The strips of the FreeStyle blood glucose monitoring system comprise a printed parallel plate coulometer, with a 50 microm gap between two facing printed electrodes, a carbon electrode and a Ag/AgCl electrode. The volume of blood between the facing plates is accurately controlled. The glucose is electrooxidized through catalysis by a glucose dehydrogenase (GDH) and an Os(2+/3+) redox mediator, which is reduced by the glucose-reduced enzyme and is electrooxidized on the carbon electrode. Initially the system used pyrroloquinoline quinone (PQQ)-dependent GDH but now uses flavin adenine dinucleotide (FAD)-dependent GDH. Because the facing electrodes are separated by such a small distance, shuttling of electrons by the redox couple could interfere with the coulometric assay. However, the Os(2+/3+) redox mediator is selected to have a substantially negative formal potential, between 0.0 and -0.2 V, versus that of the facing Ag/AgCl electrode. This makes the flow of a shuttling current between the two electrodes virtually impossible because the oxidized Os(3+) complex cannot be appreciably reduced at the more positively poised Ag/AgCl electrode. The FreeStyle Navigator continuous glucose monitoring system uses a subcutaneously implanted miniature plastic sensor connected to a transmitter to measure glycemia amperometrically and sends the information to a PDA-like device every minute. The sensor consists of a narrow (0.6 mm wide) plastic substrate on which carbon-working, Ag/AgCl reference, and carbon counter electrodes are printed in a stacked geometry. The active wired enzyme sensin

Topics: Blood Glucose; Carbon; Diabetes Mellitus; Electrochemical Techniques; Electrodes; Flavin-Adenine Dinucleotide; Glucose Dehydrogenases; Glucose Oxidase; Humans; Hydrogel, Polyethylene Glycol Dimethacrylate; Oxidation-Reduction; Point-of-Care Systems; Silver

The cDNA fragments coding for the FAD-, glycerophosphate- and calcium-binding domains of mitochondrial glycerophosphate dehydrogenase (mGDH) were synthetized using RNA extracted from freshly isolated pancreatic islets of a normal subject and two-non-insulin-dependent diabetic patients. Single strand conformation polymorphism analysis of the PCR products yielded the same mobility as control cDNA probes. Likewise, the nucleotide sequence and corresponding amino acid sequence were identical to the normal gene bank sequence. These findings argue against the presence, in pancreatic islets, of an mGDH isoform distinct from that previously characterized in extrapancreatic organs.

Topics: Aged; Amino Acid Sequence; Base Sequence; Binding Sites; Calcium; Diabetes Mellitus; DNA, Complementary; Female; Flavin-Adenine Dinucleotide; Glycerolphosphate Dehydrogenase; Glycerophosphates; Humans; Islets of Langerhans; Male; Middle Aged; Mitochondria; Molecular Sequence Data; Sequence Analysis, DNA

Topics: Animals; Diabetes Mellitus; Erythrocytes; Flavin-Adenine Dinucleotide; Flavoproteins; Glutathione Reductase; Liver; Male; Mice; Mice, Inbred Strains; Mitochondria, Liver; Riboflavin; Riboflavin Deficiency; Succinate Dehydrogenase