Stevens M J
Department of Internal Medicine, University of Michigan, Ann Arbor 48109-0678, USA.
Diabetes Technol Ther. 2001 Spring;3(1):9-22. doi: 10.1089/152091501750219985.
Cardiovascular autonomic neuropathy (CAN) is a common complication of diabetes, which results in disabling clinical manifestations and may predispose to sudden cardiac death. Recently, direct scintigraphic assessment of cardiac sympathetic integrity has become possible with the introduction of radiolabeled analogues of norepinephrine, which are actively taken up by the sympathetic nerve terminals of the heart. This article reviews how these techniques have been utilized to improve understanding of CAN complicating diabetes. Quantitative scintigraphic assessment of cardiac sympathetic innervation heart is possible with either [123I]-metaiodobenzylguanidine (MIBG) and single photon emission computed tomography (SPECT) or [11C]-hydroxyephedrine (HED) and positron emission tomography (PET). Studies in diabetic patients have explored the sensitivity of these techniques to detect CAN, characterize the effects of glycemic control on the progression of CAN and evaluate the effects of CAN on myocardial electrophysiology, blood flow regulation and function. Deficits of left ventricular (LV) [123I]-MIBG and [11C]-HED retention have been identified in diabetic subjects without abnormalities on cardiovascular reflex testing consistent with increased sensitivity to detect CAN. Poor glycemic control results in the progression of LV tracer deficits, which can be prevented or reversed by the institution of near-euglycemia. Deficits begin distally in the LV and may extend proximally. Paradoxically, however, absolute HED retention is increased in the proximal segments of the severe CAN subjects consistent with regional "hyperinnervation." These regions also exhibit abnormal blood flow regulation. Impaired myocardial MIBG uptake correlates with altered LV diastolic filling and myocardial electrophysiological deficits and is predictive of sudden death. Scintigraphic studies have provided unique insights into the effects of diabetes on cardiac sympathetic integrity and the pathophysiological consequences of LV sympathetic dysinnervation. Future studies using complementary neurotransmitter analogues will allow different aspects of regional dysfunction to be characterized with the aim of developing therapeutic strategies to prevent or reverse CAN.
心血管自主神经病变（CAN）是糖尿病常见的并发症，可导致严重的临床表现，且可能易引发心源性猝死。最近，随着去甲肾上腺素放射性标记类似物的引入，心脏交感神经完整性的直接闪烁显像评估成为可能，这些类似物可被心脏交感神经末梢主动摄取。本文综述了如何利用这些技术来增进对糖尿病合并CAN的理解。使用[123I] - 间碘苄胍（MIBG）和单光子发射计算机断层扫描（SPECT）或[11C] - 羟基麻黄碱（HED）和正电子发射断层扫描（PET）均可对心脏交感神经支配进行定量闪烁显像评估。针对糖尿病患者的研究探讨了这些技术检测CAN的敏感性，描述了血糖控制对CAN进展的影响，并评估了CAN对心肌电生理、血流调节和功能的影响。在心血管反射测试无异常的糖尿病受试者中，已发现左心室（LV）[123I] - MIBG和[11C] - HED摄取减少，这与检测CAN的敏感性增加一致。血糖控制不佳会导致LV示踪剂摄取减少的进展，而通过维持接近正常血糖水平可预防或逆转这种情况。缺损始于LV的远端，并可能向近端扩展。然而，矛盾的是，严重CAN患者近端节段的绝对HED摄取增加，与局部“神经支配过度”一致。这些区域还表现出血流调节异常。心肌MIBG摄取受损与LV舒张期充盈改变和心肌电生理缺陷相关，并可预测猝死。闪烁显像研究为糖尿病对心脏交感神经完整性的影响以及LV交感神经去神经支配的病理生理后果提供了独特的见解。未来使用互补神经递质类似物的研究将能够对局部功能障碍的不同方面进行表征，以期制定预防或逆转CAN的治疗策略。
