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.

Local release of masitinib alters in vivo implantable continuous glucose sensor performance

“…Furthermore, wireless telemetric CGM designs would avoid direct tethering and implant sub-cutaneous micromotion issues observed in this study (Helton et al, 2011). Lastly, human CGMs are recommended clinically to be best placed in subdermal adipose tissue in humans (Nielsen et al, 2005), a situation very unlikely in the murine model given lack of such analogous adipose in rodent skin. (Perez and Davis, 2008) All of these differences likely contribute to fluctuations observed in the implanted murine CGM sensor outputs (Figs.…”

Use of Continuous Glucose Monitoring in the Detection and Prevention of Hypoglycemia

“…However, an animal study by Nielsen and colleagues clearly demonstrated that measurements in the subcutaneous interstitial fat corresponded very closely with measurements in the central nervous system (CNS). 8 To summarize, interstitial fluid glucose concentration may be a better measure of functional status during periods of low glucose than capillary glucose concentration.…”

A soft and flexible biosensor using a phospholipid polymer for continuous glucose monitoring

“…Periodic finger prick tests, are often used by diabetic patients for measuring their own blood sugar level, due to the fact that glucose levels in blood can change rapidly (2.25 mg dL −1 min −1 ), often failing to detect all hypoglycaemic and hyperglycaemic events (Ricci et al 2007) as compared to other kinds of glucose sensors were reported (Sanz et al 2007;Ahmed et al, 2005;Gerritsen et al 2000;Gifford et al 2006;Lam et al 2002;Nielsen et al 2005). These glucose sensors measure blood glucose level directly by invasive method.…”