Diabetic cardiac autonomic neuropathy: Do we have any treatment perspectives?

Dihomo-γ-Linolenic Acid (20:3n-6)-Metabolism, Derivatives, and Potential Significance in Chronic Inflammation

Dihomo-γ-linolenic acid (DGLA) has emerged as a significant molecule differentiating healthy and inflamed tissues. Its position at a pivotal point of metabolic pathways leading to anti-inflammatory derivatives or via arachidonic acid (ARA) to pro-inflammatory lipid mediators makes this n-6 polyunsaturated fatty acid (PUFA) an intriguing research subject. The balance of ARA to DGLA is probably a critical factor affecting inflammatory processes in the body. The aim of this narrative review was to examine the potential roles of DGLA and related n-6 PUFAs in inflammatory conditions, such as obesity-associated disorders, rheumatoid arthritis, atopic dermatitis, asthma, cancers, and diseases of the gastrointestinal tract. DGLA can be produced by cultured fungi or be obtained via endogenous conversion from γ-linolenic acid (GLA)-rich vegetable oils. Several disease states are characterized by abnormally low DGLA levels in the body, while others can feature elevated levels. A defect in the activity of ∆6-desaturase and/or ∆5-desaturase may be one factor in the initiation and progression of these conditions. The potential of GLA and DGLA administrations as curative or ameliorating therapies in inflammatory conditions and malignancies appears modest at best. Manipulations with ∆6- and ∆5-desaturase inhibitors or combinations of long-chain PUFA supplements with n-3 PUFAs could provide a way to modify the body's DGLA and ARA production and the concentrations of their pro- and anti-inflammatory mediators. However, clinical data remain scarce and further well-designed studies should be actively promoted.

Omega-3 Nutrition Therapy for the Treatment of Diabetic Sensorimotor Polyneuropathy

Despite advances in clinical and translational research, an effective therapeutic option for diabetic sensorimotor polyneuropathy (DSP) has remained elusive. The pathomechanisms of DSP are diverse, and along with hyperglycemia, the roles of inflammatory mediators and lipotoxicity in the development of microangiopathy have been well elucidated. Omega-3 (n-3) polyunsaturated fatty acids (PUFA) are essential fatty acids with a vital role in a number of physiological processes, including neural health, membrane structure integrity, anti-inflammatory processes, and lipid metabolism. Identification of n-3 PUFA derived specialised proresolving mediators (SPM), namely resolvins, neuroprotectin, and maresins which also favour nerve regeneration, have positioned n-3 PUFA as potential treatment options in DSP. Studies in n-3 PUFA treated animal models of DSP showed positive nerve benefits in functional, electrophysiological, and pathological indices. Clinical trials in humans are limited, but recent proof-of-concept evidence suggests n-3 PUFA has a positive effect on small nerve fibre regeneration with an increase in the small nerve fiber measure of corneal nerve fibre length (CNFL). Further randomized control trials with a longer duration of treatment, higher n-3 PUFA doses, and more rigorous neuropathy measures are needed to provide a definitive understanding of the benefits of n-3 PUFA supplementation in DSP.

Effect of alpha-lipoic acid on arterial stiffness parameters in type 2 diabetes mellitus patients with cardiac autonomic neuropathy

Objective. Significantly underdiagnosed, diabetes-associated cardiac autonomic neuropathy (CAN) causes a wide range of cardiac disorders that may cause life-threatening outcomes. This study investigated the effects of alpha-lipoic acid (ALA) on arterial stiffness and insulin resistance (IR) parameters in type 2 diabetes mellitus (T2D) patients and definite CAN. Methods. A total of 36 patients with T2D and a definite stage of CAN were recruited. This investigation was carried out on two separate arms: traditional hypoglycemic therapy (n=18, control) and ALA (n=18) 600 mg in film-coated tablets/q.d. in addition to traditional hypoglycemic therapy. The duration of the study was three months. Results. In subjects with T2D and definite stage of СAN, treatment with ALA resulted in a significant decrease of glucose, immunoreactive insulin concentration, and Homeostasis Model Assessment (HOMA)-IR (HOMA-IR) parameters; pulse wave velocity (PWV), aorta augmentation index (AIxao) during the active period of the day and decrease of PWV, AIxao, and brachial augmentation index during the passive period of the day compared with the results, obtained in the control group. Therefore, the administration of ALA to patients with T2D for three months promotes the improvement of glucose metabolism and arterial stiffness parameters. Conclusions. In patients with T2D and definite stage of СAN treatment with ALA improved HOMA-IR and arterial stiffness parameters. These findings can be of clinical significance for the complex treatment of diabetes-associated CAN.

Assessment of sudomotor function in hypertensive with/without type-2 diabetes patients using SUDOSCAN: An electrophysiological study

Objective

Electrochemical skin conductance (ESC) test is a simple and non-invasive screening test can detect dysfunction of the peripheral sudomotor, and indirectly estimates the function of cardiac autonomic nerves. This study aimed to assess the ESC values in hypertensive patients with/without type-2 diabetes by using SUDOSCAN technology. Moreover, this study evaluated the role of cardiometabolic risk factors on the results of ESC test.

Methods

This cross-sectional study was carried on three groups of participants, including healthy subjects (Group I, n = 49), hypertensive without type-2 diabetes (Group II, n = 75) patients, and hypertensive with type-2 diabetes (Group III, n = 76) patients. Body mass index (BMI), blood pressure (systolic, diastolic and pulse pressure index), fasting serum glucose, and lipid profile were determined. ESC test as a measurement sudomotor function was determined by applying a small direct current at low voltage to hands and feet sensor plates through SUDOSCAN device.

Results

ESC values of the peripheral sudomotor nerves in the Group II and III patients were significantly lower than the corresponding values of Group I. SUDOSCAN results of Group II and III. Significant discriminators of cardiac autonomic neuropathy (≥30 score) that determined by the area under the curve (AUC) with 95% confidence interval (95% C.I.) were, duration of the disease, BMI, and mean blood pressure in Group II, while the duration of the disease and the BMI were significant discriminators in Group III.

Conclusions

SUDOSCAN is a simple, useful device, which can detect the impairment of peripheral autonomic small nerve fibers and the risk of cardiac autonomic neuropathy in hypertension. Moreover, the duration of the disease and the associated cardiometabolic risk factors are important predictors of significant SUDOSCAN findings.

Significance

ESC test is useful in detecting subclinical neuropathy in hypertensive patients as well as in type 2 diabetes.

Assessment of sudomotor function in hypertensive with/without type-2 diabetes patients using SUDOSCAN: An electrophysiological study

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SUDOSCAN is a simple non-invasive device that can assess the sudomotor nerves.

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Hypertensive patients have sub-clinical impairment of peripheral and autonomic nerve fibers function.

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Cardio-metabolic risk factors are important discriminators of abnormal SUDOSCAN data.

Objective

Electrochemical skin conductance (ESC) test is a simple and non-invasive screening test can detect dysfunction of the peripheral sudomotor, and indirectly estimates the function of cardiac autonomic nerves. This study aimed to assess the ESC values in hypertensive patients with/without type-2 diabetes by using SUDOSCAN technology. Moreover, this study evaluated the role of cardiometabolic risk factors on the results of ESC test.

Methods

This cross-sectional study was carried on three groups of participants, including healthy subjects (Group I, n = 49), hypertensive without type-2 diabetes (Group II, n = 75) patients, and hypertensive with type-2 diabetes (Group III, n = 76) patients. Body mass index (BMI), blood pressure (systolic, diastolic and pulse pressure index), fasting serum glucose, and lipid profile were determined. ESC test as a measurement sudomotor function was determined by applying a small direct current at low voltage to hands and feet sensor plates through SUDOSCAN device.

Results

ESC values of the peripheral sudomotor nerves in the Group II and III patients were significantly lower than the corresponding values of Group I. SUDOSCAN results of Group II and III. Significant discriminators of cardiac autonomic neuropathy (≥30 score) that determined by the area under the curve (AUC) with 95% confidence interval (95% C.I.) were, duration of the disease, BMI, and mean blood pressure in Group II, while the duration of the disease and the BMI were significant discriminators in Group III.

Conclusions

SUDOSCAN is a simple, useful device, which can detect the impairment of peripheral autonomic small nerve fibers and the risk of cardiac autonomic neuropathy in hypertension. Moreover, the duration of the disease and the associated cardiometabolic risk factors are important predictors of significant SUDOSCAN findings.

Significance

ESC test is useful in detecting subclinical neuropathy in hypertensive patients as well as in type 2 diabetes.

Cardiac Autonomic Neuropathy in Obesity, the Metabolic Syndrome and Prediabetes: A Narrative Review

Cardiac autonomic neuropathy (CAN) is a major complication of type 1 and type 2 diabetes mellitus (T1DM and T2DM). The increased morbidity, cardiovascular and all-cause mortality associated with CAN is established from numerous epidemiological studies. However, CAN is increasingly recognised in people with prediabetes (pre-DM) and the metabolic syndrome (MetS) with a reported prevalence up to 11% and 24% respectively. CAN is associated with components of MetS including hypertension and obesity, predating hyperglycaemia. The aetiology of CAN is multifactorial and there is a reciprocal relationship with insulin resistance and MetS. Obstructive sleep apnoea (OSA) is also associated with CAN possibly through MetS and an independent mechanism. An estimated global prevalence of the impaired glucose tolerance (IGT) form of pre-DM of 587 million people by 2045 means CAN will become a major clinical problem. CAN is independently associated with silent myocardial ischaemia, major cardiovascular events, myocardial dysfunction and cardiovascular mortality. Screening for CAN in pre-DM using risk scores with analysis of heart rate variability (HRV) or Sudoscan is important to allow earlier treatment at a reversible stage. The link between obesity and CAN highlights the therapeutic potential of lifestyle interventions including diet and physical activity to reverse MetS and prevent CAN. Weight loss achieved using these dietary and exercise lifestyle interventions improves the sympathetic and parasympathetic HRV indices of cardiac autonomic function. Further research is needed to identify high-risk populations of people with pre-DM or obesity that might benefit from targeted pharmacotherapy including metformin, sodium/glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide 1 (GLP-1) analogues. Bariatric surgery also improves HRV through weight loss which might also prevent CAN in severe obesity. This article reviews the literature on CAN in obesity, pre-DM and MetS, to help determine a rationale for screening, early intervention treatment and formulate future research questions in this highly prevalent condition.

Aminoguanidine reduces diabetes-associated cardiac fibrosis

Aminoguanidine (AG) inhibits advanced glycation end products (AGEs) and advanced oxidation protein products (AOPP) accumulated as a result of excessive oxidative stress in diabetes. However, the molecular mechanism by which AG reduces AGE-associated damage in diabetes is not well understood. Thus, we investigated whether AG supplementation mitigates oxidative-associated cardiac fibrosis in rats with type 2 diabetes mellitus (T2DM). Forty-five male Wistar rats were divided into three groups: Control, T2DM and T2DM+AG. Rats were fed with a high-fat, high-carbohydrate diet (HFCD) for 2 weeks and rendered diabetic using low-dose streptozotocin (STZ) (20 mg/kg), and one group was treated with AG (20 mg/kg) up to 25 weeks. In vitro experiments were performed in primary rat myofibroblasts to confirm the antioxidant and antifibrotic effects of AG and to determine if blocking the receptor for AGEs (RAGE) prevents the fibrogenic response in myofibroblasts. Diabetic rats exhibited an increase in cardiac fibrosis resulting from HFCD and STZ injections. By contrast, AG treatment significantly reduced cardiac fibrosis, α-smooth muscle actin (αSMA) and oxidative-associated Nox4 and Nos2 mRNA expression. In vitro challenge of myofibroblasts with AG under T2DM conditions reduced intra- and extracellular collagen type I expression and Pdgfb, Tgfβ1 and Col1a1 mRNAs, albeit with similar expression of Tnfα and Il6 mRNAs. This was accompanied by reduced phosphorylation of ERK1/2 and SMAD2/3 but not of AKT1/2/3 and STAT pathways. RAGE blockade further attenuated collagen type I expression in AG-treated myofibroblasts. Thus, AG reduces oxidative stress-associated cardiac fibrosis by reducing pERK1/2, pSMAD2/3 and collagen type I expression via AGE/RAGE signaling in T2DM.

Exercise training for patients with type 2 diabetes and cardiovascular disease: What to pursue and how to do it. A Position Paper of the European Association of Preventive Cardiology (EAPC)

Patients with type 2 diabetes mellitus suffer from dysregulation of a plethora of cardiovascular and metabolic functions, including dysglycaemia, dyslipidaemia, arterial hypertension, obesity and a reduced cardiorespiratory fitness. Exercise training has the potential to improve many of these functions, such as insulin sensitivity, lipid profile, vascular reactivity and cardiorespiratory fitness, particularly in type 2 diabetes mellitus patients with cardiovascular comorbidities, such as patients that suffered from an acute myocardial infarction, or after a coronary intervention such as percutaneous coronary intervention or coronary artery bypass grafting. The present position paper aims to provide recommendations for prescription of exercise training in patients with both type 2 diabetes mellitus and cardiovascular disease. The first part discusses the relevance and practical applicability of treatment targets that may be pursued, and failure to respond to these targets. The second part provides recommendations on the contents and methods to prescribe exercise training tailored to these treatment targets as well as to an optimal preparation and dealing with barriers and risks specific to type 2 diabetes mellitus and cardiac comorbidity.

A cardiac risk score based on sudomotor function to evaluate cardiovascular autonomic neuropathy in asymptomatic Chinese patients with diabetes mellitus

Backgrounds

Cardiac autonomic neuropathy is a common but always overlooked. More convenient diagnostic methods are needed.

Hypothesis

Cardiac autonomic neuropathy risk score evaluated by SUDOSCAN has a fine diagnostic efficacy detecting cardiac autonomic neuropathy.

Methods

This is a cross-sectional study among patients with diabetes mellitus. Subjects undertook SUDOSCAN tests and cardiac autonomic reflex tests, including heart rate variability due to Valsalva maneuver, heart rate response due to deep breathing and heart rate response due to standing up. Presenting 2 abnormal results was defined as cardiac autonomic neuropathy.

Results

Subjects with cardiac autonomic neuropathy has significantly higher cardiac autonomic neuropathy risk score (32.88±1.60 vs 27.64±1.24,P = 0.010). Cardiac autonomic neuropathy risk score was correlated significantly with the heart rate response due to deep breathing(P = 0.004). Multiple regression analysis including significant variables showed an independent association of cardiac autonomic neuropathy risk score and heart rate response due to deep breathing (P = 0.031) and age (P = 0.000). In receiver operating characteristic curve analysis evaluating the relationship between cardiac autonomic neuropathy risk score and cardiac autonomic neuropathy, The cut-off value was 20.5, with the sensitivity of 90.48%, the specificity of 29.5%, and the positive predictive value of 46.9%. In two-step diagnostic methods, Setting 20.5 as the cut-off value of cardiac autonomic neuropathy risk score and abnormal heart rate response due to standing up as the second diagnostic step’s positive result, and setting 16.5 as the cut-off value of cardiac autonomic neuropathy risk score and abnormal heart rate response due to deep breathing as the second diagnostic step’s positive result, both achieved good diagnostic efficacy.

Conclusion

Cardiac autonomic neuropathy risk score evaluated by SUDOSCAN is a good screening test for cardiac autonomic neuropathy. The two-step diagnostic methods could be considered as surrogate diagnostic methods.

Autonomic disturbances in diabetes: Assessment and anaesthetic implications

Diabetes mellitus is the most common medical condition and with increased awareness of heath and related issues, several patients are getting diagnosed with diabetes. The poor control of sugar and long-standing status of disease affects the autonomic system of body. The autonomic nervous system innervates cardiovascular, gastrointestinal, and genitourinary system, thus affecting important functions of the body. The cardiovascular system involvement can manifest as mild arrhythmias to sudden death. Our search for this review included PubMed, Google Search and End Note X6 version and the key words used for the search were autonomic neuropathy, diabetes, anesthesia, tests and implications. This review aims to highlight the dysfunction of autonomic system due to diabetes and its clinical presentations. The various modalities to diagnose the involvement of different systems are mentioned. An estimated 25% of diabetic patients will require surgery. It has been already established that mortality rates in diabetic patients are higher than in nondiabetic patients. Hence, complete workup is needed prior to any surgery. Diabetic autonomic neuropathy and its implications may sometimes be disastrous and further increase the incidence of in hospital morbidity and mortality. Overall, complete knowledge of diabetes and its varied effects with anaesthetic implications and careful perioperative management is the key guiding factor for a successful outcome.

Cardiac autonomic neuropathy: Risk factors, diagnosis and treatment

Cardiac autonomic neuropathy (CAN) is a serious complication of diabetes mellitus (DM) that is strongly associated with approximately five-fold increased risk of cardiovascular mortality. CAN manifests in a spectrum of things, ranging from resting tachycardia and fixed heart rate (HR) to development of "silent" myocardial infarction. Clinical correlates or risk markers for CAN are age, DM duration, glycemic control, hypertension, and dyslipidemia (DLP), development of other microvascular complications. Established risk factors for CAN are poor glycemic control in type 1 DM and a combination of hypertension, DLP, obesity, and unsatisfactory glycemic control in type 2 DM. Symptomatic manifestations of CAN include sinus tachycardia, exercise intolerance, orthostatic hypotension (OH), abnormal blood pressure (BP) regulation, dizziness, presyncope and syncope, intraoperative cardiovascular instability, asymptomatic myocardial ischemia and infarction. Methods of CAN assessment in clinical practice include assessment of symptoms and signs, cardiovascular reflex tests based on HR and BP, short-term electrocardiography (ECG), QT interval prolongation, HR variability (24 h, classic 24 h Holter ECG), ambulatory BP monitoring, HR turbulence, baroreflex sensitivity, muscle sympathetic nerve activity, catecholamine assessment and cardiovascular sympathetic tests, heart sympathetic imaging. Although it is common complication, the significance of CAN has not been fully appreciated and there are no unified treatment algorithms for today. Treatment is based on early diagnosis, life style changes, optimization of glycemic control and management of cardiovascular risk factors. Pathogenetic treatment of CAN includes: Balanced diet and physical activity; optimization of glycemic control; treatment of DLP; antioxidants, first of all α-lipoic acid (ALA), aldose reductase inhibitors, acetyl-L-carnitine; vitamins, first of all fat-soluble vitamin B1; correction of vascular endothelial dysfunction; prevention and treatment of thrombosis; in severe cases-treatment of OH. The promising methods include prescription of prostacyclin analogues, thromboxane A2 blockers and drugs that contribute into strengthening and/or normalization of Na+, K+-ATPase (phosphodiesterase inhibitor), ALA, dihomo-γ-linolenic acid (DGLA), ω-3 polyunsaturated fatty acids (ω-3 PUFAs), and the simultaneous prescription of ALA, ω-3 PUFAs and DGLA, but the future investigations are needed. Development of OH is associated with severe or advanced CAN and prescription of nonpharmacological and pharmacological, in the foreground midodrine and fludrocortisone acetate, treatment methods are necessary.

Effect of alpha lipoic acid on leukotriene A4 hydrolase

Leukotriene A₄ hydrolase is a soluble enzyme with epoxide hydrolase and aminopeptidase activities catalysing the conversion of leukotriene A₄ to leukotriene B₄ and the hydrolysis of the peptide proline-glycine-proline. Imbalances in leukotriene B₄ synthesis are related to several pathologic conditions. Currently there are no available drugs capable to modulate the synthesis of leukotriene B₄ or to block its receptors. Here we show the inhibitory profile of alpha lipoic acid on the activity of leukotriene A₄ Hydrolase. Alpha lipoic acid inhibited both activities of the enzyme at concentrations lower than 10μM. The 5-lipoxygenase inhibitor zileuton, or the 5-lipoxygenase activating protein inhibitor MK-886, were unable to inhibit the activity of the enzyme. Acute promyelocytic leukaemia HL-60 cells were differentiated to leukotriene A₄ hydrolase expressing neutrophil-like cells. Alpha lipoic acid inhibited the aminopeptidase activity of the cytosolic fraction from neutrophil-like cells but had no effect on the cytosolic fraction from undifferentiated cells. Docking and molecular dynamic approximations revealed that alpha lipoic acid participates in electrostatic interactions with K-565 and R-563, which are key residues for the carboxylate group recognition of endogenous substrates by the enzyme. Alpha lipoic acid is a compound widely used in clinical practice, most of its therapeutic effects are associated with its antioxidants properties, however, antioxidant effect alone is unable to explain all clinical effects observed with alpha lipoic acid. Our results invite to evaluate the significance of the inhibitory effect of alpha lipoic acid on the catalytic activity of leukotriene A₄ hydrolase using in vivo models.

Differentiation of Diabetes by Pathophysiology, Natural History, and Prognosis

The American Diabetes Association, JDRF, the European Association for the Study of Diabetes, and the American Association of Clinical Endocrinologists convened a research symposium, "The Differentiation of Diabetes by Pathophysiology, Natural History and Prognosis" on 10-12 October 2015. International experts in genetics, immunology, metabolism, endocrinology, and systems biology discussed genetic and environmental determinants of type 1 and type 2 diabetes risk and progression, as well as complications. The participants debated how to determine appropriate therapeutic approaches based on disease pathophysiology and stage and defined remaining research gaps hindering a personalized medical approach for diabetes to drive the field to address these gaps. The authors recommend a structure for data stratification to define the phenotypes and genotypes of subtypes of diabetes that will facilitate individualized treatment.

Stress-related biobehavioral responses, symptoms, and physical activity among female veterans in the community: An exploratory study

BACKGROUND

Female veterans experience multiple stresses during their lifetime. Some of them seek care in the civilian community. Common physical and psychological symptoms among female veterans include pain, fatigue, sleep quality, and depression. Physical activity has the potential to improve their well-being.

OBJECTIVES

This study was guided by the concept of allostasis. The purpose of the study was to determine the associations among stress-related biobehavioral responses and symptoms as well as to determine if physical activity moderated these associations among female veterans.

DESIGN/SETTINGS/PARTICIPANTS/METHODS

A cross-sectional and exploratory design was implemented among 82 female veterans (46±10.57years old) at a community event. Self-reported questionnaires and blood and hair samples were collected. Descriptive statistics and multivariate analyses were applied in this secondary data analysis.

FINDINGS

Female veterans experienced moderate perceived stress and greater body mass index, C-reactive protein, and hair cortisol levels at the same time as they reported moderate levels of pain and fatigue, poor sleep quality, and considerable depressive symptoms. The findings showed that greater body mass index was significantly associated with more severe pain and poor sleep quality. Physical activity negatively moderated the relationship between perceived stress and pain.

CONCLUSION

Female veterans need services to manage body weight and help them engage in physical activity. Nurse educators are responsible for instructing nurses to properly identify female veterans in the civilian community facility and to provide care in a respectful manner.