Musen Gail, Simonson Donald C, Bolo Nicolas R, Driscoll Amy, Weinger Katie, Raji Annaswamy, Théberge Jean, Renshaw Perry F, Jacobson Alan M
Research Division, Joslin Diabetes Center, 1 Joslin Place Room 350, Boston, Massachusetts 02215, USA.
J Clin Endocrinol Metab. 2008 Apr;93(4):1450-7. doi: 10.1210/jc.2007-2007. Epub 2008 Jan 15.
Mechanisms underlying the brain response to hypoglycemia are not well understood.
Our objective was to determine the blood glucose level at which the hypothalamus and other brain regions are activated in response to hypoglycemia in type 1 diabetic patients and control subjects.
This was a cross-sectional study evaluating brain activity using functional magnetic resonance imaging in conjunction with a hyperinsulinemic hypoglycemic clamp to lower glucose from euglycemia (90 mg/dl) to hypoglycemia (50 mg/dl).
The study was performed at the Brain Imaging Center in the McLean Hospital.
Seven type 1 diabetic patients between 18 and 50 yr old and six matched control subjects were included in the study.
Hyperinsulinemic hypoglycemic clamp was performed.
Blood glucose level at peak hypothalamic activation, amount of regional brain activity during hypoglycemia in both groups, and difference in regional brain activation between groups were calculated.
The hypothalamic region activates at 68 +/- 9 mg/dl in control subjects and 76 +/- 8 mg/dl in diabetic patients during hypoglycemia induction. Brainstem, anterior cingulate cortex, uncus, and putamen were activated in both groups (P < 0.001). Each group also activated unique brain areas not active in the other group.
This application of functional magnetic resonance imaging can be used to identify the glucose level at which the hypothalamus is triggered in response to hypoglycemia and whether this threshold differs across patient populations. This study suggests that a core network of brain regions is recruited during hypoglycemia in both diabetic patients and control subjects.
大脑对低血糖反应的潜在机制尚未完全明确。
我们的目的是确定1型糖尿病患者和对照受试者在低血糖反应时，下丘脑及其他脑区被激活的血糖水平。
这是一项横断面研究，采用功能磁共振成像结合高胰岛素低血糖钳夹技术，将血糖从正常血糖水平（90mg/dl）降至低血糖水平（50mg/dl），以评估大脑活动。
该研究在麦克莱恩医院的脑成像中心进行。
纳入7名年龄在18至50岁之间的1型糖尿病患者和6名匹配的对照受试者。
实施高胰岛素低血糖钳夹。
计算下丘脑激活峰值时的血糖水平、两组低血糖期间脑区活动量以及两组脑区激活差异。
在低血糖诱导期间，对照受试者下丘脑区域在血糖水平为68±9mg/dl时被激活，糖尿病患者在血糖水平为76±8mg/dl时被激活。两组的脑干、前扣带回皮质、钩回和壳核均被激活（P<0.001）。每组还激活了另一组未激活的独特脑区。
这种功能磁共振成像应用可用于识别低血糖反应时下丘脑被触发的血糖水平，以及该阈值在不同患者群体中是否存在差异。本研究表明，糖尿病患者和对照受试者在低血糖期间均会激活一个核心脑区网络。
