Autonomic diabetic neuropathies: A brief overview.

This article summarizes the latest epidemiology of diabetic autonomic neuropathy (DAN), and provides a brief overview on epidemiology, current outcomes measures for screening and diagnosis in research and clinical settings, the latest evidence on effective management, and novel perspectives on the impacts of social determinants of health in development and management of DAN. Among the various forms of diabetic neuropathy, distal symmetric polyneuropathy and diabetic autonomic neuropathies, particularly cardiovascular autonomic neuropathy, are by far the most studied. However, emerging data highlight the impact of other forms of autonomic neuropathies such as gastrointestinal and urogenital autonomic neuropathies, on healthcare and patients' reported outcomes [1].

The Association Between Cardiovascular Autonomic Function and Changes in Kidney and Myocardial Function in Type 2 Diabetes and Healthy Controls.

Background: The mechanisms linking cardiovascular autonomic neuropathy, diabetic kidney disease and cardiovascular mortality in type 2 diabetes are widely unknown. We investigated the relationship between baseline cardiovascular autonomic function and changes in kidney and myocardial function over six years in patients with type 2 diabetes and healthy controls. Methods: Post-hoc analysis of a cohort study in 24 patients with type 2 diabetes and 18 healthy controls. Baseline determinants were cardiovascular autonomic reflex tests (heart rate response to: standing (30:15); deep breathing (E:I); and the Valsalva test) and time- and frequency-domain heart rate variability indices. Outcomes were changes in estimated glomerular filtration rate (eGFR), albuminuria, myocardial flow reserve (MFR) measured by cardiac 82Rb Positron emission tomography computed tomography (PET/CT), and coronary artery calcium score (CACS). Results: Mean age at inclusion was 61 ± 10 years and 36% were female. Mean follow up time was 6 ± 0 years. A lower response in heart rate to the Valsalva test (corresponding to weaker autonomic function) was associated with a larger decline in eGFR (p=0.04), but not significantly after adjustment for sex, baseline age, smoking status, systolic blood pressure, heart rate, HbA1c, body mass index and baseline eGFR (p=0.12). A higher baseline response in heart rate to standing (30:15) was associated with a larger decline in myocardial flow reserve in the unadjusted analysis (p=0.02) and after adjustment (p=0.02). A higher response in heart rate to the Valsalva maneuver was associated with a larger increase in CACS (p = 0.02), but the association became insignificant after adjustment (p = 0.16). Conclusion: A lower response in heart rate to the Valsalva test was associated with a larger decline in kidney function, indicating that autonomic dysfunction may predict future loss of kidney function. However, we did not find any association between lower values in cardiovascular autonomic function at baseline and a worsening in albuminuria, myocardial function, or atherosclerotic burden.

Essential Oil of Croton zehntneri Prevents Conduction Alterations Produced by Diabetes Mellitus on Vagus Nerve.

Autonomic diabetic neuropathy (ADN) is a complication of diabetes mellitus (DM), to which there is no specific treatment. In this study, the efficacy of the essential oil of Croton zehntneri (EOCz) in preventing ADN was evaluated in the rat vagus nerve. For the two fastest conducting myelinated types of axons of the vagus nerve, the conduction velocities and rheobase decreased, whilst the duration of the components of the compound action potential of these fibers increased. EOCz completely prevented these DM-induced alterations of the vagus nerve. Unmyelinated fibers were not affected. In conclusion, this investigation demonstrated that EOCz is a potential therapeutic agent for the treatment of ADN.

Suppression Failure of Cortisol Secretion by Dexamethasone May Occur in Glucagon-like Peptide-1 Receptor Agonist-treated Patients with Diabetic Autonomic Neuropathy.

Two diabetic women (case 1, 75 years old; case 2, 49 years old) being treated with glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs) showed no suppression of cortisol secretion on a dexamethasone suppression test (DST). However, its secretion was suppressed after switching from GLP-1 RAs to insulin. We also checked the cortisol secretion by a DST in five consecutive inpatients (case 3-7) being treated with GLP-1 RAs. The coefficients of R-R interval variation at rest and during deep breathing were lower in the two false-positive cases (case 1 and 2) than in the five true-negative cases (case 3-6). GLP-1 RAs can be switched to insulin in order to eliminate the slow absorption effect of dexamethasone by GLP-1 RAs if a DST is planned in diabetic patients receiving GLP-1 RAs.

O efeito do uso de antioxidantes na prevenção e tratamento da neuropatia diabética no sistema nervoso entérico / The use of antioxidants in the prevention and treatment of diabetic neuropathy in the enteric nervous system

O Diabetes mellitus (DM) é um distúrbio metabólico, complexo e de etiologia múltipla. Esta doença causa prejuízos aos sistemas vasculares e nervosos que se manifestam na forma de macro e microangiopatias e neuropatias diabéticas com alta incidência e prevalência na população mundial. Entre as neuropatias existentes, a neuropatia autonômica afeta o trato gastrointestinal (TGI) e caracteriza-se por alterações degenerativas em componentes do sistema nervoso entérico, como neurônios e células gliais. Consequentemente, ocorrem modificações na secreção e motilidade do TGI que são responsáveis por sintomas comuns da doença, tais como náuseas, inchaço, dor abdominal, diarreia, entre outros. Estudos experimentais e clínicos sugerem que o estresse oxidativo esteja envolvido na patogênese e na progressão da neuropatia diabética autonômica no sistema nervoso entérico. Assim, compostos antioxidantes que previnem a formação e/ou neutralizam os radicais livres oriundos do estresse oxidativo podem ter um papel relevante no tratamento das complicações neurológicas do diabetes mellitus. Neste artigo, realizou-se uma revisão da literatura sobre os principais aspectos, quadro clínico e patogênese do DM e a ocorrência da neuropatia diabética autônoma no sistema nervoso entérico, abordando as principais pesquisas que empregaram antioxidantes para prevenir e/ou tratar os danos neurológicos que são consequências desta patologia.

Diabetes mellitus (DM) is a metabolic complex disorder of multiple etiology. This disease causes damage to the vascular and nervous systems that are seen as macro- and microangiopathies and diabetic neuropathies, with high incidence and prevalence in the world population. Among the existing neuropathies, the autonomic neuropathy affects the gastrointestinal (GI) tract and is characterized by degenerative changes in components of the enteric nervous system, such as neurons and glial cells. Accordingly, changes occur in secretion and motility of the GIT, which are responsible for common symptoms, such as nausea, bloating, abdominal pain, diarrhea, among others. Experimental and clinical studies suggest that oxidative stress is involved in the pathogenesis and progression of autonomic diabetic neuropathy in the enteric nervous system. Thus, antioxidant compounds that prevent the formation and/or neutralize free radicals derived from oxidative stress may play a role in the treatment of neurological complications of diabetes mellitus. In this article, a literature review is performed on the main aspects of the clinical presentation and the pathogenesis of diabetes and autonomous diabetic neuropathy in the enteric nervous system. It also addresses the main research employing antioxidants to prevent and/or treat neurological damages that are consequences of this disease.