Background: Microdialysis of subcutaneous adipose tissue may provide an opportunity to monitor glucose continuously, when the device is connected to an extracorporal glucose sensor. We assessed whether our microdialysis probes are capable of measuring adipose tissue glucose over a prolonged period in Type 1 diabetic patients. Furthermore, the relationship between abdominal skinfold thickness and glucose recovery and the effect of spontaneous glucose excursions on its recovery were evaluated.
Methods: Microdialysis probes were pairwise inserted subcutaneously into the abdominal fat and remained in situ for 3 weeks in eight Type 1 diabetic patients. At days 1, 3, 4, 8, 11, 16, and 18 of probe retention, glucose, as measured by microdialysis, was compared to capillary blood glucose concentrations during a 4 h period. The recovery of glucose obtained by microdialysis was expressed as a percentage of the capillary blood glucose concentration.
Results: Eleven of the 16 inserted probes (69%) were evaluable during the complete study. Recovery of glucose was lower at day 1 and 3 (51+/-23% and 56+/-18%, respectively, mean+/-S.D.) compared to values found afterwards (67+/-19%, 72+/-13%, 76+/-14%, 71+/-16%, and 76+/-18%, for day 4, 8, 11, 16, and 18, respectively, for all P<0.05 vs. day 1 and 3). Skinfold thickness was inversely related to the overall 3 week glucose recovery (r=-0.76; P<0.03). Recovery was similar over a wide range of capillary blood glucose concentrations.
Conclusions: Prolonged in vivo retention of microdialysis probes improves the recovery and lowers the variability of adipose tissue-sampled glucose in Type 1 diabetic patients. These findings show that microdialysis-based glucose measurements offer an opportunity for prolonged glucose monitoring.