Subject:
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IGMD 1: Functional imaging IGMD 5: Health aging / healthy living IGMD 5: Health aging / healthy living NCEBP 14: Cardiovascular diseases NCMLS 4: Energy and redox metabolism IGMD 1: Functional imaging ONCOL 3: Translational research NCMLS 4: Energy and redox metabolism Tijdelijke code tbv inlezen publicaties Radboudumc - Alleen voor gebruik door Radboudumc |
Organization:
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Internal Medicine Radiology Paediatrics - OUD tm 2017 |
Abstract:
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The objective of this study was to investigate the relationship between plasma and brain glucose levels during euglycemia and hypoglycemia in healthy subjects and patients with type 1 diabetes mellitus (T1DM). Hyperinsulinemic euglycemic (5 mmol/L) and hypoglycemic (3 mmol/L) [1-(13)C]glucose clamps were performed in eight healthy subjects and nine patients with uncomplicated T1DM (HbA(1c) 7.7 +/- 1.4%). Brain glucose levels were measured by (13)C magnetic resonance spectroscopy. Linear regression analysis was used to fit the relationship between plasma and brain glucose levels and calculate reversible Michaelis-Menten (MM) kinetic parameters. Brain glucose values during euglycemia (1.1 +/- 0.4 mumol/g vs. 1.1 +/- 0.3 mumol/g; P = 0.95) and hypoglycemia (0.5 +/- 0.2 mumol/g vs. 0.6 +/- 0.3 mumol/g; P = 0.52) were comparable between healthy subjects and T1DM patients. MM kinetic parameters of combined data were calculated to be maximum transport rate/cerebral metabolic rate of glucose (T(max)/CMR(glc)) = 2.25 +/- 0.32 and substrate concentration at half maximal transport (K(t)) = 1.53 +/- 0.88 mmol/L, which is in line with previously published data obtained under hyperglycemic conditions. In conclusion, the linear MM relationship between plasma and brain glucose can be extended to low plasma glucose levels. We found no evidence that the plasma to brain glucose relationship or the kinetics describing glucose transport over the blood-brain barrier differ between healthy subjects and patients with uncomplicated, reasonably well-controlled T1DM.
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