Matyka K, Evans M, Lomas J, Cranston I, Macdonald I, Amiel S A
Department of Medicine, King's College School of Medicine and Dentistry, London, U.K.
Diabetes Care. 1997 Feb;20(2):135-41. doi: 10.2337/diacare.20.2.135.
To investigate the effect of normal aging on the protective responses against hypoglycemia, in view of the fact that type II diabetes is primarily a disease of aging, and its treatment is associated with risk of hypoglycemia with cognitive impairment.
Plasma glucose was lowered stepwise from 5 to 2.4 mmol/l and restored by manipulation of an infusion of 20% glucose during 220-min intravenous infusion of 1.5 mU.kg-1.min-1 soluble insulin in 14 men; 7 were aged 60-70 years and the other 7 were 22-26 years. Changes in neurohumoral responses, subjective awareness, and choice reaction time were assessed.
Hormonal responses were similar in the two groups, but symptoms began earlier in the younger men (at a plasma glucose of 3.6 +/- 0.1 vs. 3.0 +/- 0.2 mmol/l, P = 0.02) and were more intense (P = 0.03). Four-choice reaction time, a measure of psychomotor coordination, deteriorated earlier in the older men (at a plasma glucose of 3.0 +/- 0.1 vs. 2.6 +/- 0.1 mmol/l, P = 0.07) and to a greater degree. The difference between the glucose level for subjective awareness of hypoglycemia and the onset of cognitive dysfunction was lost in the older men (0.0 +/- 0.2 vs. 0.8 +/- 0.1 mmol/l, P < 0.007).
Older men are prone to more severe cognitive impairment during hypoglycemia than younger men and are less likely to experience prior warning symptoms if blood glucose falls. This effect of normal aging may contribute to the risk of severe hypoglycemia in older diabetic patients treated with sulfonylureas and insulin.
鉴于2型糖尿病主要是一种衰老相关疾病，且其治疗与低血糖伴认知障碍风险相关，研究正常衰老对低血糖保护反应的影响。
在14名男性中，通过静脉输注1.5 mU·kg-1·min-1可溶性胰岛素220分钟期间，将血浆葡萄糖从5 mmol/l逐步降至2.4 mmol/l，并通过调整20%葡萄糖输注量使其恢复；其中7名年龄在60 - 70岁，另外7名年龄在22 - 26岁。评估神经体液反应、主观意识和选择反应时间的变化。
两组的激素反应相似，但年轻男性的症状出现更早（血浆葡萄糖为3.6±0.1 mmol/l时出现症状，而老年男性为3.0±0.2 mmol/l，P = 0.02）且更强烈（P = 0.03）。作为心理运动协调指标的四选反应时间，老年男性恶化更早（血浆葡萄糖为3.0±0.1 mmol/l时，而年轻男性为2.6±0.1 mmol/l，P = 0.07）且程度更大。老年男性低血糖主观意识的血糖水平与认知功能障碍发作之间的差异消失（分别为0.0±0.2 mmol/l和0.8±0.1 mmol/l，P < 0.007）。
老年男性在低血糖期间比年轻男性更容易出现更严重的认知障碍，且血糖下降时不太可能出现预先警示症状。正常衰老的这种影响可能导致老年糖尿病患者在使用磺脲类药物和胰岛素治疗时发生严重低血糖的风险增加。
