BackgroundDifferent lines of evidence suggest that oxidative stress (OS) is implicated in the pathogenesis of diabetic neuropathy. The Semmes–Weinstein monofilament (SWM) test is an efficient tool for evaluating diabetic polyneuropathy and diabetic foot. In this study, we analyzed the association between OS markers and altered SWM test results in type 2 diabetes (T2DM) patients.MethodsSeventy T2DM patients were studied and 34 showed altered SWM results. The clinical and biochemical parameters were determined using standardized methods. Levels of oxidized glutathione (GSSG) and malondialdehyde (MDA) were measured in circulating mononuclear cells using high-performance liquid chromatography.ResultsWe found that T2DM patients with altered SWM test results had significantly higher GSSG (3.53 ± 0.31 vs. 3.31 ± 0.35 mmol/ml, p < 0.05) and MDA (1.88 ± 0.16 vs. 1.75 ± 0.19 nmol/ml, p < 0.01) values compared to diabetic patients with normal SWM test outcomes. Moreover, altered SWM test results were independently related to age, glycosylated hemoglobin, and GSSG levels, but there was no association between OS markers and altered neuropathy sensitivity score (NSS) values.ConclusionsAlteration of the glutathione system and MDA values in T2DM patients are associated with loss of proprioceptive (pressure) sensitivity, but not with symptomatic polyneuropathy (as evaluated by NSS). This finding may be important for understanding how OS affects distal symmetric polyneuropathy in diabetic patients.

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Background: Diabeticperipheralneuropathy(DPN)isachroniccomplicationofdiabetes mellitus associated with high morbidity and mortality. Major risk factors for DPNincludemetabolicchanges,durationofdiabetes,nerveischaemiaandderangementsinregenerationandnerverepairprogrammes.Chemokineshavebeenpreviouslyimplicatedinthepathogenesisofvariousneuropathiesandneuropathicpain processes.Theaimofthispilotstudywastoevaluatetheassociationbetweenthe plasmalevelsofchemokines(CXCL9,CXCL10andCXCL11)inthepresenceofDPN inacohortoftype2diabetes(T2D)patients. Materials and methods: Westudied73patientswithT2D:36withDPNand37without DPN. DPN was established through the Semmes-Weinstein test (SW). Plasma levelsofcirculatingchemokinesCXCL9,CXCL10andCXCL11weredeterminedusing DuoSetELISAkits(Abingdon,UK). Results: WefoundthatlevelsofCXCL10weresignificantlyhigherinpatientswithDPN than amongst patients without DPN (57.6 ± 38.3 vs 38.1 ± 33.4 pg/mL, respectively; P =.034).SerumlevelsofchemokineCXCL9werealsohigheramongst patients with DPN but did not reach a statistical significance (188.1 ± 72.7 and 150.4 ±83.6pg/mL,respectively,P =.06). Conclusions: Increased circulating levels of CXCL10 were associated with DPN in T2D patients, suggesting a role of this chemokine in the DPN. Determination of CXCL10levelscouldbeusedasamarkerfortheearlydetectionandimplementation oftherapeuticstrategiesinordertoreverseandpreventtheDPN.ThisisanopenaccessarticleunderthetermsoftheCreativeCommonsAttribution-NonCommercialLicense,whichpermitsuse,distributionandreproduction inanymedium,providedtheoriginalworkisproperlycitedandisnotusedforcommercialpurposes.

The authors have withdrawn this preprint due to author disagreement.