title: Oxidative stress predicts progression of peripheral and cardiac autonomic nerve dysfunction over 6 years in diabetic patients.
abstract: Oxidative stress is implicated in the pathogenesis of experimental diabetic neuropathy, but prospective studies in diabetic patients are lacking. We aimed to evaluate whether the plasma levels of various biomarkers of oxidative stress predict the progression of diabetic neuropathy and mortality over 6 years. We followed 89 diabetic patients aged 54 ± 14 years (59 % with polyneuropathy), 72 of whom underwent nerve function reassessment after 6.2 ± 0.8 years, whereas 17 died after 4.2 ± 1.0 years. Plasma markers of oxidative stress at baseline included superoxide anion, hypochlorous acid, peroxynitrite, 8-iso-prostaglandin F2α, vitamin E/lipid ratio, and vitamin C. Neuropathy was assessed by symptoms and deficits, motor and sensory nerve conduction velocity (MNCV, SNCV), vibration perception thresholds (VPT), thermal detection thresholds, and heart rate variability (HRV). Despite a reduction in HbA1c by 1.4 ± 1.6 % (p < 0.001), median SNCV, sural SNCV, peroneal MNCV, malleolar VPT, and warm TDT deteriorated after 6 years (all p < 0.05). In multivariate models, increased superoxide generation was associated with a decline in median SNCV (β = -0.997; p = 0.036) and deterioration in HRV at rest (OR 1.63 [95 % CI 1.09-2.44]; p = 0.017) over 6 years. Low vitamin E/lipid ratio tended to predict a decrease in peroneal MNCV (β = 0.781; p = 0.057) and an increase in malleolar VPT (β = -0.725; p = 0.077). Plasma superoxide generation was associated with an increased risk of mortality (HR 23.2 [95 % CI 1.05-513]; p = 0.047). In conclusion, increased plasma superoxide generation predicted the decline in sensory and cardiac autonomic nerve function and mortality over 6 years in diabetic patients, but larger studies are required for confirmation.
authors.affiliation: Institute for Clinical Diabetology, Leibniz Center for Diabetes Research, German Diabetes Center at Heinrich Heine University, Auf'm Hennekamp 65, 40225, Düsseldorf, Germany, dan.ziegler@ddz.uni-duesseldorf.de.
authors.forename: Dan
authors.initials: D
authors.lastname: Ziegler
authors.forename: Stefanie
authors.initials: S
authors.lastname: Buchholz
authors.forename: Christoph
authors.initials: C
authors.lastname: Sohr
authors.forename: Jaffar
authors.initials: J
authors.lastname: Nourooz-Zadeh
authors.forename: Michael
authors.initials: M
authors.lastname: Roden
mesh_terms: D000328:Adult; D000368:Aged; D017776:Autonomic Pathways / Q000473:pathology / Q000503:physiopathology*; D003922:Diabetes Mellitus, Type 1 / Q000150:complications; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003929:Diabetic Neuropathies / Q000209:etiology / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006321:Heart / Q000294:innervation* / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction; D018384:Oxidative Stress; D010525:Peripheral Nerves / Q000473:pathology / Q000503:physiopathology*; D011446:Prospective Studies; D013481:Superoxides / Q000097:blood
chemical_list: D013481:Superoxides