Cardiovascular autonomic neuropathy in diabetes: Pathophysiology, clinical assessment and implications

Quantification of lipoproteins by proton nuclear magnetic resonance spectroscopy (1H-NMRS) improves the prediction of cardiac autonomic dysfunction in patients with type 1 diabetes

AIMS

To assess if advanced characterization of serum glycoprotein and lipoprotein profile, measured by proton nuclear magnetic resonance spectroscopy (1H-NMRS) improves a predictive clinical model of cardioautonomic neuropathy (CAN) in subjects with type 1 diabetes (T1D).

METHODS

Cross-sectional study (ClinicalTrials.gov Identifier: NCT04950634). CAN was diagnosed using Ewing's score. Advanced characterization of macromolecular complexes including glycoprotein and lipoprotein profiles in serum samples were measured by 1H-NMRS. We addressed the relationships between these biomarkers and CAN using correlation and regression analyses. Diagnostic performance was assessed by analyzing their areas under the receiver operating characteristic curves (AUCROC).

RESULTS

Three hundred and twenty-three patients were included (46% female, mean age and duration of diabetes of 41 ± 13 years and 19 ± 11 years, respectively). The overall prevalence of CAN was 28% [95% confidence interval (95%CI): 23; 33]. Glycoproteins such as N-acetylglucosamine/galactosamine and sialic acid showed strong correlations with inflammatory markers such as high-sensitive C-reactive protein, fibrinogen, IL-10, IL-6, and TNF-α. On the contrary, we did not find any association between the former and CAN. A stepwise binary logistic regression model (R2 = 0.078; P = 0.003) retained intermediate-density lipoprotein-triglycerides (IDL-TG) [β:0.082 (95%CI: 0.005; 0.160); P = 0.039], high-density lipoprotein-triglycerides (HDL-TGL)/HDL-Cholesterol [β:3.633 (95%CI: 0.873; 6.394); P = 0.010], and large-HDL particle number [β: 3.710 (95%CI: 0.677; 6.744); P = 0.001] as statistically significant determinants of CAN. Adding these lipoprotein particles to a clinical prediction model of CAN that included age, duration of diabetes, and A1c enhanced its diagnostic performance, improving AUCROC from 0.546 (95%CI: 0.404; 0.688) to 0.728 (95%CI: 0.616; 0.840).

CONCLUSIONS

When added to clinical variables, 1H-NMRS-lipoprotein particle profiles may be helpful to identify those patients with T1D at risk of CAN.

Clinical Implications of Diabetic Peripheral Neuropathy in Primary Infrapopliteal Angioplasty Approach for Neuro-Ischemic Foot Wounds

BACKGROUND

To assess the clinical effects of diabetic peripheral neuropathy (DPN) in patients with chronic limb-threatening ischemia (CLTI) treated by primary infrapopliteal angioplasty for neuro-ischemic Rutherford 5, foot wounds.

MATERIALS AND METHODS

Over a 10-year period (2009-2019), a series of 304 diabetic ischemic limbs adding or not evincible neuropathic affectation were treated by primary infrapopliteal angioplasty and their files were retrospectively reviewed. Mean length of treated arterial lesions was 6.1 cm (range 1-22 cm). Inferior limb vibration perception threshold diagnostic was performed for comparing and scoring detectable DPN in all studied diabetic patients (classed from 0 to 10 points). There were 19% limbs with normal (0-1 points) perception (group 1), 55% others with "mild" and "moderate" (2-6 points) neuropathic impairment (group 2), and 26% limbs showing "severe" (7-10 points) DPN (group 3).

RESULTS

Primary infrapopliteal angioplasty succeeded in 89% cases in group 1, in 82% in group 2, and in 68% of limbs in group 3. This latest group assembled the heaviest neuropathic affectation and arterial calcifications and proved the lowest clinical benefit at 36 months: 35% (95% confidence interval [CI]=22% to 48%) of primary patency, 36% (95% CI=22% to 50%) wound healing, and 54% (95% CI=39% to 69%) limb preservation rates. A comparison between groups 1 vs 3 and 2 vs 3 of primary patency (p=0.014 and p=0.043), tissue healing (p=0.049 and p=0.01), and limb salvage (p=0.006 and p=0.023) proved significant, yet without statistical weight for group 1 vs 2 (p>0.05). Overall survival was not significantly affected between groups (p=0.34).

CONCLUSION

The presence of severe DPN may jeopardize the results of infrapopliteal angioplasty in terms of patency, tissue cicatrization, and limb preservation, yet without significance on survival of these patients. When present, DPN requires appropriate stratification as specific indicator in CLTI treatment.

Comparison of western diet-induced obesity and streptozotocin mouse models: insights into energy balance, somatosensory dysfunction, and cardiac autonomic neuropathy

Metabolic disorders such as obesity and type 2 diabetes (T2D) are increasingly prevalent worldwide, necessitating a deeper comprehension of their underlying mechanisms. However, translating findings from animal research to human patients remains challenging. This study aimed to investigate the long-term effects of Streptozotocin (STZ) on metabolic, cardiac, and somatosensory function in mice fed a Western diet (WD) of high fat, sucrose, and cholesterol with low doses of STZ administration compared to mice fed WD alone. In our research, we thoroughly characterized energy balance and glucose homeostasis, as well as allodynia and cardiac function, all of which have been previously shown to be altered by WD feeding. Notably, our findings revealed that the treatment of WD-fed mice with STZ exacerbated dysfunction in glucose homeostasis via reduced insulin secretion in addition to impaired peripheral insulin signaling. Furthermore, both WD and WD + STZ mice exhibited the same degree of cardiac autonomic neuropathy, such as reduced heart rate variability and decreased protein levels of cardiac autonomic markers. Furthermore, both groups developed the same symptoms of neuropathic pain, accompanied by elevated levels of activating transcription factor 3 (Atf3) in the dorsal root ganglia. These discoveries enhance our understanding of metabolic activity, insulin resistance, neuropathy, and cardiac dysfunction of diet-induced models of obesity and diabetes. The exacerbation of impaired insulin signaling pathways by STZ did not lead to or worsen cardiac and somatosensory dysfunction. Additionally, they offer valuable insights into suitable diet induced translational mouse models, thereby advancing the development of potential interventions for associated conditions.

Diabetic Neuropathies

OBJECTIVE

This article provides an up-to-date review of the diagnosis and management of the most common neuropathies that occur in patients with diabetes.

LATEST DEVELOPMENTS

The prevalence of diabetes continues to grow worldwide and, as a result, the burden of diabetic neuropathies is also increasing. Most diabetic neuropathies are caused by hyperglycemic effects on small and large fiber nerves, and glycemic control in individuals with type 1 diabetes reduces neuropathy prevalence. However, among people with type 2 diabetes, additional factors, particularly metabolic syndrome components, play a role and should be addressed. Although length-dependent distal symmetric polyneuropathy is the most common form of neuropathy, autonomic syndromes, particularly cardiovascular autonomic neuropathy, are associated with increased mortality, whereas lumbosacral radiculoplexus neuropathy and treatment-induced neuropathy cause substantial morbidity. Recent evidence-based guidelines have updated the recommended treatment options to manage pain associated with distal symmetric polyneuropathy of diabetes.

ESSENTIAL POINTS

Identifying and appropriately diagnosing the neuropathies of diabetes is key to preventing progression. Until better disease-modifying therapies are identified, management remains focused on diabetes and metabolic risk factor control and pain management.

A High intensity Interval training (running and swimming) and resistance training intervention on heart rate variability and the selected biochemical factors in boys with type 1 diabetes

OBJECTIVE

The purpose of this research is to investigate the effect of High Intensity Interval Training and Resistance training (HIITR) on heart rate variability (HRV), blood glucose, and plasma biomarkers levels in adolescents with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

24 boys with T1D (FBS: 274.66 ± 52.99, age: 15.2 ± 1.78 years, and BMI = 19.61 ± 1.11) and 12 healthy boys (FBS: 92.75 ± 5.22, age: 15.08 ± 1.67 years, and BMI = 20.26 ± 2.66) were divided into three groups: Diabetes Training (DT, n = 12), Diabetes Control (DC, n = 12), and Healthy Control (HC, n = 12). HRV (24 h) was computed in time and frequency domains, anthropometric, biochemical parameters at rest, and aerobic capacity (VO2peak) obtained during a graded exercise testing (GXT). All variables were evaluated at the baseline and following 12 weeks of exercise training, done 3 days weekly. The statistical method used for data analysis was analysis of covariance (ANCOVA) test.

RESULTS

HRV, Hemoglobin A1c (HbA1c) and Fasting blood sugar (FBS), VO2peak, norepinephrine (NEP), and HDL-C indicated significant differences between both T1D groups compared to HC at baseline (p < 0.001). BMI, LDL-C, TC, and TG parameters were similar in all groups. HRV parameters, VO2peak and HDL-C, and NEP were significantly improved by exercise training, and HbA1c and FBS levels were significantly reduced (p < 0.001). There is a negative and significant correlation between LF/HF Ratio Difference (post-test minus pre-test) and VO2Peak Difference variables (post-test minus pre-test) (p < 0.001).

CONCLUSIONS

The present study suggests the importance of early screening for CVD risk factors in adolescent males with T1D. Also, it was revealed HIITR training compared to other training patterns, and cardiovascular health improves via enhancement of autonomic modulation, VO2peak, plasma lipids, and catecholamine levels.

Chest pain symptoms during myocardial infarction in patients with and without diabetes: a systematic review and meta-analysis

OBJECTIVE

Chest pain (CP) is key in diagnosing myocardial infarction (MI). Patients with diabetes mellitus (DM) are at increased risk of an MI but may experience less CP, leading to delayed treatment and worse outcomes. We compared the prevalence of CP in those with and without DM who had an MI.

METHODS

The study population was people with MI presenting to healthcare services. The outcome measure was the absence of CP during MI, comparing those with and without DM. Medline and Embase databases were searched to 18 October 2021, identifying 9272 records. After initial independent screening, 87 reports were assessed for eligibility against the inclusion criteria, quality and risk of bias assessment (Strengthening the Reporting of Observational Studies in Epidemiology and Newcastle-Ottawa criteria), leaving 22 studies. The meta-analysis followed Meta-analysis Of Observational Studies in Epidemiology criteria and reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled ORs, weights and 95% CIs were calculated using a random-effects model.

RESULTS

This meta-analysis included 232 519 participants from 22 studies and showed an increased likelihood of no CP during an MI for those with DM, compared with those without. This was 43% higher in patients with DM in the cohort and cross-sectional studies (OR: 1.43; 95% CI: 1.26 to 1.62), and 44% higher in case-control studies (OR: 1.44; 95% CI: 1.11 to 1.87).

CONCLUSION

In patients with an MI, patients with DM are less likely than those without to have presentations with CP recorded. Clinicians should consider an MI diagnosis when patients with DM present with atypical symptoms and treatment protocols should reflect this, alongside an increased patient awareness on this issue.

PROSPERO REGISTRATION NUMBER

CRD42017058223.

Cardiac innervations in diabetes mellitus-Anatomical evidence of neuropathy

The extensive innervations of the heart include a complex network of sympathetic, parasympathetic, and sensory nerves connected in loops that serve to regulate cardiac output. Metabolic dysfunction in diabetes affects many different organ systems, including the cardiovascular system; it causes cardiac arrhythmias, silent myocardial ischemia, and sudden cardiac death, among others. These conditions are associated with damage to the nerves that innervate the heart, cardiac autonomic neuropathy (CAN), which is caused by various pathophysiological mechanisms. In this review, the main facts about the anatomy of cardiac innervations and the current knowledge of CAN, its pathophysiological mechanisms, and its diagnostic approach are discussed. In addition, anatomical evidence for CAN from human and animal studies has been summarized.

The Role of Echocardiography in Evaluating Cardiovascular Diseases in Patients with Diabetes Mellitus

Patients with diabetes mellitus are highly susceptible to cardiovascular complications, which are directly correlated with cardiovascular morbidity and mortality. In addition to coronary artery disease, there is growing awareness of the risk and prevalence of heart failure (HF) in patients with diabetes. Echocardiography is an essential diagnostic modality commonly performed in patients with symptoms suggestive of cardiovascular diseases (CVD), such as dyspnea or chest pain, to establish or rule out the cause of symptoms. Conventional echocardiographic parameters, such as left ventricular ejection fraction, are helpful not only for diagnosing CVD but also for determining severity, treatment strategy, prognosis, and response to treatment. Echocardiographic myocardial strain, a novel echocardiographic technique, enables the detection of early changes in ventricular dysfunction before HF symptoms develop. This article aims to review the role of echocardiography in evaluating CVD in patients with diabetes mellitus and how to use it in patients with suspected cardiac diseases.

Polyneuropathy Associated with Age of Starting the Transfusion and Serum Ferritin Level in Iranian Patients with Thalassemia Major and Intermedia

Considering the importance of managing patients with β-thalassemia and the importance of early detection of disease complications, we examined the rate of sensorimotor neuropathy in patients with β-thalassemia and the risk factors related to it. This cross-sectional study included 44 blood transfusion-dependent β-thalassemia patients aged 5 years and older. Nerve conduction studies (NCSs) were performed via standard procedures for both motor and sensory nerves. Neuropathy was observed in 14 patients (31.8%). NCS results for sensorimotor nerves in patients were within normal range. In motor NCS results, increased ulnar nerve amplitude was observed in patients with increasing age, and peroneal nerve delay in patients with an increase in serum ferritin level (p < 0.05). In sensory NCS results, delayed ulnar and sural nerves latencies were found in patients with an increase in serum ferritin level (p < 0.05). We provide data that sensorimotor neuropathy exists in thalassemia patients. It seems that with the increase of serum ferritin level and the age of patients, neuropathy becomes more obvious, while other factors such as gender, body mass index, and the number of transfusions may not be associated with neuropathy.

Sex differences and sex steroids influence on the presentation and severity of cardiovascular autonomic neuropathy of patients with type 1 diabetes

BACKGROUND

Sex differences characterize cardiovascular outcomes in patients with type 1 diabetes. Cardioautonomic neuropathy is a common complication of type 1 diabetes that associates increased morbi-mortality. Data regarding the interplay between sex and cardiovascular autonomic neuropathy are scarce and controversial in these patients. We aimed to address sex-related differences in the prevalence of seemingly asymptomatic cardioautonomic neuropathy in type 1 diabetes, and their associations with sex steroids.

METHODS

We conducted a cross-sectional study including 322 consecutively recruited patients with type 1 diabetes. Cardioautonomic neuropathy was diagnosed using Ewing's score and power spectral heart rate data. We assessed sex hormones by liquid chromatography/tandem mass spectrometry.

RESULTS

When considering all subjects as a whole, asymptomatic cardioautonomic neuropathy prevalence was not significantly different between women and men. When age was taken into account, the prevalence of cardioautonomic neuropathy was similar among young men and those > 50 years. However, in women > 50 years, the prevalence of cardioautonomic neuropathy doubled that of young women [45.8% (32.6; 59.7) vs. 20.4% (13.7; 29.2), respectively]. The OR of having cardioautonomic neuropathy was 3.3 higher in women > 50 years than in their younger counterparts. Furthermore, women presented more severe cardioautonomic neuropathy than men. These differences were even more marked when women were classified according their menopausal status instead of age. Peri- and menopausal women had an OR 3.5 (1.7; 7.2) of having CAN compared with their reproductive-aged counterparts [CAN prevalence: 51% (37; 65) vs. 23% (16; 32), respectively]. A binary logistic regression model (R²: 0.161; P = 0.001) displayed age > 50 years as a significant determinant of cardioautonomic neuropathy only in women. Androgens were positively associated with heart rate variability in men, and negatively in women. Accordingly, cardioautonomic neuropathy was associated with increased testosterone/estradiol ratio in women but to decreased testosterone concentrations in men.

CONCLUSIONS

Menopause in women with type 1 diabetes is accompanied by an increase in the prevalence of asymptomatic cardioautonomic neuropathy. This age-related excess risk of cardioautonomic neuropathy is not observed in men. Men and women with type 1 diabetes have opposite associations between circulating androgens and indexes of cardioautonomic function. Trial registration ClinicalTrials.gov Identifier: NCT04950634.

Diabetes Mellitus and Heart Failure: Epidemiology, Pathophysiologic Mechanisms, and the Role of SGLT2 Inhibitors

Diabetes mellitus (DM) and heart failure (HF) are frequently encountered afflictions that are linked by a common pathophysiologic background. According to landmark studies, those conditions frequently coexist, and this interaction represents a poor prognostic indicator. Based on mechanistic studies, HF can be propagated by multiple pathophysiologic pathways, such as inflammation, oxidative stress, endothelial dysfunction, fibrosis, cardiac autonomic neuropathy, and alterations in substrate utilization. In this regard, DM may augment myocardial inflammation, fibrosis, autonomic dysfunction, and lipotoxicity. As the interaction between DM and HF appears critical, the new cornerstone in DM and HF treatment, sodium-glucose cotransporter-2 inhibitors (SGLT2i), may be able to revert the pathophysiology of those conditions and lead to beneficial HF outcomes. In this review, we aim to highlight the deleterious pathophysiologic interaction between DM and HF, as well as demonstrate the beneficial role of SGLT2i in this field.

Renal Sympathetic Hyperactivity in Diabetes Is Modulated by 5-HT1D Receptor Activation via NO Pathway

Renal vasculature, which is highly innervated by sympathetic fibers, contributes to cardiovascular homeostasis. This renal sympathetic outflow is inhibited by 5-HT in normoglycaemic rats. Considering that diabetes induces cardiovascular complications, we aimed to determine whether diabetic state modifies noradrenergic input at renal level and its serotonergic modulation in rats. Alloxan diabetic rats were anaesthetized (pentobarbital; 60 mg/kg i.p.) and prepared for in situ autoperfusion of the left kidney to continuously measure systemic blood pressure (SBP), heart rate (HR), and renal perfusion pressure (RPP). Electrical stimulation of renal sympathetic outflow induces frequency-dependent increases (Δ) in RPP (23.9 ± 2.1, 59.5 ± 1.9, and 80.5 ± 3.5 mm Hg at 2, 4, and 6 Hz, respectively), which were higher than in normoglycaemic rats, without modifying HR or SBP. Intraarterial bolus of 5-HT and 5-CT (5-HT_1/5/7 agonist) reduced electrically induced ΔRPP. Only L-694,247 (5-HT_1D agonist) reproduced 5-CT inhibition on sympathetic-induced vasoconstrictions, whereas it did not modify exogenous noradrenaline-induced ΔRPP. 5-CT inhibition was exclusively abolished by i.v. bolus of LY310762 (5-HT_1D antagonist). An inhibitor of guanylyl cyclase, ODQ (i.v.), completely reversed the L-694,247 inhibitory effect. In conclusion, diabetes induces an enhancement in sympathetic-induced vasopressor responses at the renal level. Prejunctional 5-HT_1D receptors, via the nitric oxide pathway, inhibit noradrenergic-induced vasoconstrictions in diabetic rats.

Home-based exercise program in the indeterminate form of Chagas disease (PEDI-CHAGAS study): A study protocol for a randomized clinical trial

Background

Chagas disease (CD) is a neglected endemic disease with worldwide impact due to migration. Approximately 50-70% of individuals in the chronic phase of CD present the indeterminate form, characterized by parasitological and/or serological evidence of Trypanosoma cruzi infection, but without clinical signs and symptoms. Subclinical abnormalities have been reported in indeterminate form of CD, including pro-inflammatory states and alterations in cardiac function, biomarkers and autonomic modulation. Moreover, individuals with CD are usually impacted on their personal and professional life, making social insertion difficult and impacting their mental health and quality of life (QoL). Physical exercise has been acknowledged as an important strategy to prevent and control numerous chronic-degenerative diseases, but unexplored in individuals with the indeterminate form of CD. The PEDI-CHAGAS study (which stands for "Home-Based Exercise Program in the Indeterminate Form of Chagas Disease" in Portuguese) aims to evaluate the effects of a home-based exercise program on physical and mental health outcomes in individuals with indeterminate form of CD.

Methods and design

The PEDI-CHAGAS is a two-arm (exercise and control) phase 3 superiority randomized clinical trial including patients with indeterminate form of CD. The exclusion criteria are <18 years old, evidence of non-Chagasic cardiomyopathy, musculoskeletal or cognitive limitations that preclude the realization of exercise protocol, clinical contraindication for regular exercise, and regular physical exercise (≥1 × per week). Participants will be assessed at baseline, and after three and 6 months of follow-up. The primary outcome will be QoL. Secondary outcomes will include blood pressure, physical fitness components, nutritional status, fatigability, autonomic modulation, cardiac morphology and function, low back pain, depression and anxiety, stress, sleep quality, medication use and adherence, and biochemical, inflammatory and cardiac biomarkers. Participants in the intervention group will undergo a home-based exercise program whilst those in the control group will receive only general information regarding the benefits of physical activity. Both groups will receive the same general nutritional counseling consisting of general orientations about healthy diets.

Conclusion

The findings from the present study may support public health intervention strategies to improve physical and mental health parameters to be implemented more effectively in this population.

Clinical trial registration

[https://ensaiosclinicos.gov.br/rg/RBR-10yxgcr9/], identifier [U1111-1263-0153].

Point-of-care sural nerve conduction could predict the presence of cardiovascular autonomic neuropathy in type 1 diabetes mellitus

AIMS

Assessment for cardiovascular autonomic neuropathy (CAN) in patients with type 1 diabetes mellitus remains time-consuming in the clinical setting. We aimed to examine the diagnostic performance of a portable point-of-care diagnostic tool (POCD) for assessing sural nerve conduction during the screening of CAN.

METHODS

Nerve amplitude (AMP_POCD ) and conduction velocity (CV_POCD ) were measured in a cross-sectional study including 198 asymptomatic patients with type 1 diabetes. CAN was diagnosed by the Ewing score and power spectral heart rate [low-frequency (LF) and high-frequency (HF) activity]. Diagnostic accuracy was determined by ROC curves.

RESULTS

CV_POCD and AMP_POCD showed positive correlations with LF and HF, and a negative correlation with age. Overall, AMP_POCD had an 81.7% accuracy in identifying CAN [AUC = 0.817 (95% CI 0.692-0.942)] with an AMP_POCD  ≤6 μV showing 90% sensitivity and 73% specificity. In a stepwise binary logistic regression analysis, the model (R² : 0.297; P < 0.001) retained the duration of type 1 diabetes [β: 1.131 (95% CI: 1.051-1.216); P = 0.001) and A_1c [β: 2.131 (95% CI: 1.060-4.283); P = 0.034) as significant predictors of CAN. The combination of AMP_POCD  ≤6 μV + a type 1 diabetes duration of ≥8 years maximized the sensitivity, showing a diagnostic performance of 87% [AUC = 0.867 (95% CI 0.769-0.965)] with 90%, 76%, and 99%, sensitivity, specificity, and NPV, respectively. Adding A_1c  ≥ 7% to this model maintained accuracy [AUC = 0.867 (95% CI: 0.788-0.963) and NPV (99%), while increasing specificity to 84%.

CONCLUSIONS

The combination of AMP_POCD with A_1c and the duration of type 1 diabetes mellitus showed a good performance for the detection of asymptomatic CAN, making POCD an easy and rapid test for its routine screening in the clinical setting.

Age and Disease Duration Independent Cardiac Autonomic Neuropathy in Patients with Diabetic Foot Complications: Case-Control Study

INTRODUCTION

Cardiac autonomic neuropathy (CAN) in people with diabetes is associated with high mortality. We aimed to study age and disease duration, independent prevalence of CAN in people with diabetic foot complications.

METHODS

530 patients with diabetes were screened to undergo CAN assessment (automated CANS-analyser). CAN was defined as "early", "definite," or "severe" according to the Toronto consensus. History pertaining to autonomic symptoms, prior cardiovascular events (CVE), and assessment for peripheral neuropathy was done. Participants were grouped into those with diabetic foot complication (group A, n = 82) [Charcot foot (n = 42), diabetic foot ulcer (n = 40)]; with DPN without foot complications (group B, n = 82); and without DPN or foot complications (group C, n = 82).

RESULTS

Symptoms of autonomic dysfunction were prominent in people with foot complications than the other groups. Resting heart rate was significantly greater in those with foot complications [99.89 ± 26.71 (group A) vs. 86.99 ± 22.24 (group B) vs. 88.32 ± 17.08 (group C); P = 0.001]. The prevalence of CAN was 75.6% in group A (51.2% early, 12.2% definite, 12.2% severe), 57.2% in group B (45.1% early, 12.2% severe) and 58.5% in group C (43.9% early, 1.2% definite, 13.4% severe) (P = 0.002). Patients with foot complications were more likely to have CAN (75.6% vs. 57.9%, P < 0.001). Charcot foot had higher prevalence of CAN (78.6%) as compared with those with DFU (72.5%) or without DFU or DPN (57.9%), P < 0.001.

CONCLUSION

CAN is present in more than two-third of patients with diabetes and foot complications with highest prevalence in Charcot neuroarthropathy.

Fluoxetine Treatment Decreases Cardiac Vagal Input and Alters the Serotonergic Modulation of the Parasympathetic Outflow in Diabetic Rats

Comorbid diabetes and depression constitutes a major health problem, worsening associated cardiovascular diseases. Fluoxetine's (antidepressant) role on cardiac diabetic complications remains unknown. We determined whether fluoxetine modifies cardiac vagal input and its serotonergic modulation in male Wistar diabetic rats. Diabetes was induced by alloxan and maintained for 28 days. Fluoxetine was administered the last 14 days (10 mg/kg/day; p.o). Bradycardia was obtained by vagal stimulation (3, 6 and 9 Hz) or i.v. acetylcholine administrations (1, 5 and 10 μg/kg). Fluoxetine treatment diminished vagally-induced bradycardia. Administration of 5-HT originated a dual action on the bradycardia, augmenting it at low doses and diminishing it at high doses, reproduced by 5-CT (5-HT_1/7 agonist). 5-CT did not alter the bradycardia induced by exogenous acetylcholine. Decrease of the vagally-induced bradycardia evoked by high doses of 5-HT and 5-CT was reproduced by L-694,247 (5-HT_1D agonist) and blocked by prior administration of LY310762 (5-HT_1D antagonist). Enhancement of the electrical-induced bradycardia by 5-CT (10 μg/kg) was abolished by pretreatment with SB269970 (5-HT₇ receptor antagonist). Thus, oral fluoxetine treatment originates a decrease in cardiac cholinergic activity and changes 5-HT modulation of bradycardic responses in diabetes: prejunctional 5-HT₇ receptors augment cholinergic-evoked bradycardic responses, whereas prejunctional 5-HT_1D receptors inhibit vagally-induced bradycardia.

Diabetes modulation of the myocardial infarction- acute kidney injury axis

Since there is crosstalk in functions of the heart and kidney, acute or chronic injury in one of the two organs provokes adaptive and/or maladaptive responses in both organs, leading to cardiorenal syndrome (CRS). Acute kidney injury (AKI) induced by acute heart failure is referred to as type 1 CRS, and a frequent cause of this type of CRS is acute myocardial infarction (AMI). Diabetes mellitus increases the risk of AMI and also the risk of AKI of various causes. However, there have been only a few studies in which animal models of diabetes were used to examine how diabetes modulates AMI-induced AKI. In this review, we summarize findings regarding the mechanisms of type 1 CRS and the impact of diabetes on both AMI and renal susceptibility to AKI and we discuss mechanisms by which diabetes modulates AMI-induced AKI. Hemodynamic alterations induced by AMI could be augmented by diabetes via its detrimental effect on infarct size and contractile function of the non-infarcted region in the heart. Diabetes increases susceptibility of renal cells to hypoxia and oxidative stress by modulation of signaling pathways that regulate cell survival and autophagy. Recent studies have shown that diabetes mellitus even at early stage of cardiomyopathy/nephropathy predisposes the kidney to AMI-induced AKI, in which activation of toll-like receptors and reactive oxygen species derived from NADPH oxidases are involved. Further analysis of crosstalk between diabetic cardiomyopathy and diabetic kidney disease is necessary for obtaining a more comprehensive understanding of modulation of the AMI-AKI axis by diabetes.