Schramm E, Wagner M, Nellessen U, Inselmann G
Universität Würzburg, Würzburg; Johanniter-Krankenhaus Stendal, Stendal, Germany.
Eur J Clin Invest. 2000 Apr;30(4):311-6. doi: 10.1046/j.1365-2362.2000.00631.x.
Autonomic neuropathy resulting from long-term diabetes mellitus may affect heart innervation. However, so far diabetes induced morphological changes of cardiac nerves are not well-known. In this study human cardiac atrial tissue from diabetic patients was analysed by electron microscopy for structural alterations as a result of diabetic neuropathy.
In coronary bypass surgery, an edge of the right auricle was routinely resected for reason of extracorporal circulation. Thin cardiac tissue sections of 100 nm were studied by electron microscopy. Atrial tissue samples were collected from 5 patients with long-standing diabetes (for at least 8 years) and compared to atrial tissue samples from 5 patients without diabetes, equally undergoing coronary bypass surgery.
In all atria-free nerve endings with unmyelinized, axons were observed. Cross sections of 479 axons from diabetic patients were compared to 419 axons of nondiabetic patients. The number of altered axons was significantly higher in cardiac tissue of diabetic patients (32%) in comparison to normal subjects (17%). In diabetic patients, 20% of the intra-axonal mitochondria were condensed or hydropic, whereas in nondiabetic patients only 4% of the mitochondria were altered. Membrane fragments were present in 21% of the axons in atria of diabetic patients compared to 10% in nondiabetic subjects. Only in cardiac axons from diabetic patients there were lamellar bodies, dissolved axoplasma and junctions between neighbouring axons in a minor number. Few vacuoles were present in axons of both groups.
In myocardial atrial-free nerve fibre bundles of diabetic patients, the amount of degenerative changes was higher in comparison to atrial cardiac tissue from nondiabetic subjects. These morphological alterations may indicate manifestation of diabetic neuropathy and might contribute to the impairment of autonomic neural control affecting the heart in long-standing diabetes mellitus.
长期糖尿病导致的自主神经病变可能影响心脏神经支配。然而，迄今为止，糖尿病引起的心脏神经形态学变化尚不清楚。在本研究中，通过电子显微镜分析糖尿病患者的人心房组织，以观察糖尿病神经病变导致的结构改变。
在冠状动脉搭桥手术中，出于体外循环的原因，常规切除右心耳边缘。通过电子显微镜研究100纳米的薄心脏组织切片。从5例长期糖尿病患者（至少8年）中收集心房组织样本，并与5例同样接受冠状动脉搭桥手术的非糖尿病患者的心房组织样本进行比较。
在所有心房中均观察到无髓鞘轴突的游离神经末梢。将479例糖尿病患者的轴突横截面与419例非糖尿病患者的轴突进行比较。与正常受试者（17%）相比，糖尿病患者心脏组织中改变的轴突数量显著更高（32%）。在糖尿病患者中，20%的轴突内线粒体浓缩或呈水样变性，而在非糖尿病患者中，只有4%的线粒体发生改变。糖尿病患者心房轴突中有21%存在膜碎片，而非糖尿病患者为10%。仅在糖尿病患者的心脏轴突中存在少数板层小体、溶解的轴浆和相邻轴突之间的连接。两组轴突中均有少量空泡。
与非糖尿病受试者的心房心肌组织相比，糖尿病患者心肌无房纤维束中的退行性变化更多。这些形态学改变可能表明糖尿病神经病变的表现，并可能导致长期糖尿病中影响心脏的自主神经控制受损。
