title: Continuous glucose monitoring in interstitial subcutaneous adipose tissue and skeletal muscle reflects excursions in cerebral cortex.
abstract: Continuous glucose monitoring (CGM) is being explored using several types of glucose sensors. Some are designed for subcutaneous adipose tissue. It is important to determine to which extent these glucose fluctuations in different tissues reflect changes taking place in the central nervous system, where glucose sensing is thought to occur. We studied the ability of subcutaneous adipose interstitial fluid measurements to parallel glucose propagations in blood, muscle, and central nervous system (CNS) during hyper- and hypoglycemia. A subcutaneous CGM system was applied in the CNS, subcutaneous adipose tissue, and skeletal muscle of nine Vietnamese potbellied pigs, and data were compared with frequent sampling in blood. Alterations in glucose levels were induced with intravenous glucose and insulin. During hyperglycemia, no difference was detected in delay between blood and interstitial glucose levels in subcutaneous adipose tissue (18.0 +/- 0.8 min), muscle (18.0 +/- 0.9 min), and CNS (20.3 +/- 1.2 min), respectively. During hypoglycemia, we found no time difference between interstitial parameters in the three tissues. However, the amplitude of glucose changes varied considerably, with a smaller magnitude of glucose change taking place in the brain. The timing of glucose excursions in subcutaneous adipose tissue and muscle reflect excursions in CNS. The reduced magnitude of glucose excursions in the brain suggests that different mechanisms of glucose transport are operative in CNS compared with subcutaneous adipose tissue and muscle.
authors.affiliation: Medical Department M (Endocrinology and Diabetes), Arhus Sygehus, Arhus University Hospital, DK-8000 Arhus C, Denmark.
authors.forename: Jannik Kruse
authors.initials: JK
authors.lastname: Nielsen
authors.forename: Christian Born
authors.initials: CB
authors.lastname: Djurhuus
authors.forename: Claus Højbjerg
authors.initials: CH
authors.lastname: Gravholt
authors.forename: Andreas Christiansen
authors.initials: AC
authors.lastname: Carus
authors.forename: Jacob
authors.initials: J
authors.lastname: Granild-Jensen
authors.forename: Hans
authors.initials: H
authors.lastname: Orskov
authors.forename: Jens Sandahl
authors.initials: JS
authors.lastname: Christiansen
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D045604:Extracellular Fluid / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006943:Hyperglycemia / Q000378:metabolism; D007003:Hypoglycemia / Q000378:metabolism; D017551:Microdialysis / Q000295:instrumentation / Q000379:methods; D008991:Monitoring, Physiologic; D018482:Muscle, Skeletal / Q000378:metabolism*; D013552:Swine
chemical_list: D005947:Glucose