TY - JOUR A1 - Baum, Petra A1 - Toyka, Klaus V. A1 - Blüher, Matthias A1 - Kosacka, Joanna A1 - Nowicki, Marcin T1 - Inflammatory mechanisms in the pathophysiology of diabetic peripheral neuropathy (DN) — new aspects JF - International Journal of Molecular Sciences N2 - The pathogenesis of diabetic neuropathy is complex, and various pathogenic pathways have been proposed. A better understanding of the pathophysiology is warranted for developing novel therapeutic strategies. Here, we summarize recent evidence from experiments using animal models of type 1 and type 2 diabetes showing that low-grade intraneural inflammation is a facet of diabetic neuropathy. Our experimental data suggest that these mild inflammatory processes are a likely common terminal pathway in diabetic neuropathy associated with the degeneration of intraepidermal nerve fibers. In contrast to earlier reports claiming toxic effects of high-iron content, we found the opposite, i.e., nutritional iron deficiency caused low-grade inflammation and fiber degeneration while in normal or high non-heme iron nutrition no or only extremely mild inflammatory signs were identified in nerve tissue. Obesity and dyslipidemia also appear to trigger mild inflammation of peripheral nerves, associated with neuropathy even in the absence of overt diabetes mellitus. Our finding may be the experimental analog of recent observations identifying systemic proinflammatory activity in human sensorimotor diabetic neuropathy. In a rat model of type 1 diabetes, a mild neuropathy with inflammatory components could be induced by insulin treatment causing an abrupt reduction in HbA1c. This is in line with observations in patients with severe diabetes developing a small fiber neuropathy upon treatment-induced rapid HbA1c reduction. If the inflammatory pathogenesis could be further substantiated by data from human tissues and intervention studies, anti-inflammatory compounds with different modes of action may become candidates for the treatment or prevention of diabetic neuropathy. KW - diabetic neuropathy KW - pathogenesis KW - inflammation KW - iron KW - treatment-induced neuropathy in diabetes (TIND) Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284556 SN - 1422-0067 VL - 22 IS - 19 ER - TY - THES A1 - Frank, Franziska T1 - Veränderung der Ranvier’schen Schnürringarchitektur bei Patienten mit diabetischer Neuropathie T1 - Disruption of the nodal architecture in patients with diabetic neuropathy N2 - In der Krankheitsentstehung der diabetischen Neuropathie wird die paranodale Demyelinisierung als ein möglicher Pathomechanismus diskutiert, wobei Studien mit Gewebeproben von Patienten aufgrund der Invasivität limitiert sind. In der vorliegenden Studie wurden periphere Nervenfasern in Hautbiopsien von Patienten mit diabetischer Neuropathie und in Patienten mit Diabetes mellitus ohne Neuropathie untersucht. Ziel war es, nodale und paranodale Veränderungen, wie eine Dispersion der paranodalen Proteine Caspr und Neurofascin oder der nodalen Na-Kanäle, zu detektieren und die Proben auf verlängerte Ranvier`sche Schnürringe zu untersuchen. Es wurde die Hypothese überprüft, dass paranodale Demyelinisierungen bei Patienten mit diabetischer Neuropathie in Hautbiopsien, als minimal-invasive Methode, nachweisbar sind. Hautproben von Patienten mit Diabetes mellitus ohne Neuropathie sollten zudem in einem frühen Krankheitsstadium untersucht werden. Für die Untersuchung konnten 35 Patienten mit einer diabetischen Neuropathie, 17 Patienten mit Diabetes mellitus und 31 Kontrollen eingeschlossen werden. Immunfluoreszenzfärbungen mit Antikörpern gegen Caspr, Neurofascin und Natrium-Kanälen wurden zur Analyse der Ranvier`schen Schnürringarchitektur durchgeführt und ausgewertet. Eine erhöhte Anzahl an verlängerten Schnürringen, als Zeichen einer segmentalen Demyelinisierung, konnte in den Patienten mit diabetischer Neuropathie aber auch in Patienten mit Diabetes mellitus nachgewiesen werden. Weiterhin waren vermehrt Veränderungen der paranodalen Proteine, wie eine Dispersion von Caspr und Neurofascin in den Proben des Fingers der Patienten mit diabetischer Neuropathie sowie eine Dispersion von Neurofascin im Unterschenkel in beiden Patientengruppen nachweisbar. Interessanterweise waren einzelne Veränderungen auch in den gesunden Kontrollen auffindbar. Veränderungen der Schnürringarchitektur lassen sich mithilfe der Hautbiopsie nachweisen und quantifizieren. Nodale und paranodale Veränderungen weisen auf demyelinisierende Prozesse in Patienten mit diabetischer Neuropathie hin und finden sich auch bereits in einem frühen Krankheitsstadium. N2 - During the course of diabetic neuropathy, paranodal demyelination has been discussed as a possible mechanism, although studies with tissue samples from patients are limited due to its invasiveness. In the present study, peripheral nerve fibers were examined in skin biopsies from patients with diabetic neuropathy and in patients with diabetes mellitus without neuropathy. The aim was to detect nodal and paranodal changes, such as a dispersion of the paranodal proteins Caspr and Neurofascin or the nodal sodium channels, and to examine the samples for elongated nodes of Ranvier. The hypothesis was tested that paranodal demyelination in patients with diabetic neuropathy can be detected in skin biopsies as a minimally invasive method. Skin samples from patients with diabetes mellitus without neuropathy should also be examined at an early stage of the disease. 35 patients with diabetic neuropathy, 17 patients with diabetes mellitus and 31 controls could be included in the study. Immunofluorescence staining with antibodies against Caspr, Neurofascin and sodium channels were carried out and evaluated in order to analyze the architecture of nodes of Ranvier. An increased number of elongated nodes, as a sign of segmental demyelination, could be demonstrated in patients with diabetic neuropathy, but also in patients with diabetes mellitus. An increased number of changes in paranodal proteins, such as a dispersion of Caspr and Neurofascin in the samples of the finger of the patients with diabetic neuropathy and a dispersion of Neurofascin in the lower leg in both patient groups, were detectable. Interestingly, alterations of the nodal architecture could also be found in healthy controls. A disruption of the architecture of the node of Ranvier can be detected and quantified using skin biopsies. Nodal and paranodal alterations indicate demyelinating processes in patients with diabetic neuropathy and are also found at an early stage of the disease. KW - Ranvier-Schnürring KW - Diabetische Neuropathie KW - Diabetes mellitus KW - Hautbiopsie KW - skin biopsy KW - Caspr KW - Neurofascin KW - Caspr KW - Neurofascin KW - node of Ranvier KW - diabetic neuropathy Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-219668 ER -