Plasma leptin level is associated with cardiac autonomic dysfunction in patients with type 2 diabetes: HSCAA study

Cardiac autonomic neuropathy modified the association between obesity and hypoglycemia in type 2 diabetes

BACKGROUND

Previous studies have shown that increasing body mass index (BMI) was associated with decreased hypoglycemia in type 2 diabetes, but it remains uncertain whether this finding could be applied to patients with and without cardiac autonomic neuropathy (CAN).

METHODS

The study included 7789 participants with type 2 diabetes from action to control cardiovascular risk in diabetes (ACCORD) trail. CAN was defined as SDNN < 8.2 ms and RMSSD < 8.0 ms. Obesity was defined as BMI ≥ 30 kg/m2. Outcomes were identified as severe hypoglycemia requiring any assistance (HAA) or requiring medical assistance (HMA). We assessed the association between obesity and severe hypoglycemia in type 2 diabetes with or without CAN using COX regression models adjusted for baseline characteristics.

RESULTS

Over a median follow-up of 4.7 years, a total of 893 participants developed HAA and 584 participants developed HMA. Compared with non-obesity, obesity was associated with lower risk of severe hypoglycemia (HAA: hazard ratio [HR] 0.51, 95% confidence interval [CI] 0.38-0.68, P < 0.001; HMA: HR 0.57, 95% CI 0.40-0.82, P = 0.002) in CAN present group, but not in CAN absent group (HAA: HR 0.98, 95% CI 0.83-1.16, P = 0.830; HMA: HR 0.97, 95% CI 0.79-1.19, P = 0.754). Similarly, increasing BMI was associated with reduced severe hypoglycemic events in participants with CAN, but not in participants without CAN.

CONCLUSIONS

CAN modifies the association between obesity and hypoglycemia in type 2 diabetes. Type 2 diabetic individuals with CAN who are under weight control should pay attention to hypoglycemic events.

TRIAL REGISTRY

http://www.

CLINICALTRIALS

gov . Unique identifier: NCT00000620.

Comparison of changes in adipokine and inflammatory cytokine levels in patients with newly diagnosed type 2 diabetes treated with exenatide, insulin, or pioglitazone: A post-hoc study of the CONFIDENCE trial

Background

Adipokines and inflammatory cytokines (ADICs) play important roles in type 2 diabetes mellitus (T2DM). This study aimed to compare the changes of ADIC levels (ΔADICs) in patients with newly diagnosed T2DM treated with different antihyperglycemic agents, and further investigate the impact of these changes on metabolic indices, β-cell function and insulin resistance (IR).

Methods

Four hundred and sixteen patients with newly diagnosed T2DM from 25 centers in China randomly received 48-week intervention with exenatide, insulin or pioglitazone. Anthropometric and laboratory data, indices of β-cell function and IR, and levels of AIDCs, including interleukin-1 beta (IL-1β), interferon-gamma (IFN-γ), leptin, and fibroblast growth factor 21 (FGF21) were detected at baseline and the end of the study.

Results

In total, 281 participants (68 % male, age: 50.3 ± 9.4 years) completed the study. After 48- week treatment, IL-1β and IFN-γ were significantly decreased with exenatide treatment (P < 0.001 and P = 0.001, respectively), but increased with insulin (P = 0.009 and P = 0.026, respectively). However, pioglitazone treatment had no impact on ADICs. No significant change in leptin or FGF21 was detected with any of the treatments. After adjustment for baseline values and changes of body weight, waist and HbA1c, the between-group differences were found in ΔIL-1β (exenatide vs. insulin: P = 0.048; and exenatide vs. pioglitazone: P = 0.003, respectively) and ΔIFN-γ (exenatide vs. insulin: P = 0.049; and exenatide vs. pioglitazone: P < 0.001, respectively). Multiple linear regression analysis indicated that Δweight was associated with ΔIL-1β (β = 0.753; 95 % CI, 0.137-1.369; P = 0.017). After adjusting for treatment effects, Δweight was also be correlated with ΔFGF21 (β = 1.097; 95%CI, 0.250-1.944; P = 0.012); furthermore, ΔHOMA-IR was correlated with Δleptin (β = 0.078; 95%CI, 0.008-0.147; P = 0.029) as well. However, ΔHOMA-IR was not significantly associated with ΔIL-1β after adjusting for treatment effects (P = 0.513).

Conclusion

Exenatide treatment led to significant changes of inflammatory cytokines levels (IL-1β and IFN-γ), but not adipokines (leptin and FGF21), in newly diagnosed T2DM patients. The exenatide-mediated improvement in weight and IR may be associated with a decrease in inflammatory cytokine levels.

Impacts of Chemerin Levels and Antioxidant Capacity on the Severity of Cardiovascular Autonomic Neuropathy in Patients with Type 2 Diabetes and Prediabetes

Existing evidence supports an association between chemerin levels and cardiovascular risk, while reduced thiol levels are linked to diabetes mellitus. It is hypothesized that chemerin may contribute to autonomic dysfunction and cardiovascular risk in type 2 diabetes mellitus (T2DM), potentially mediated by the antioxidant capacity of patients with well-controlled T2DM and prediabetes. Comprehensive cardiovascular autonomic testing and biomarker assessments were conducted for all participants. The severity of cardiovascular autonomic neuropathy (CAN) was evaluated using the composite autonomic scoring scale (CASS). A mediation model was employed to explore the potential relationships among chemerin levels, antioxidant capacity (indicated by thiol levels), and CAN severity (indicated by CASS values). A total of 184 participants were enrolled in this study, comprising 143 individuals with T2DM and 40 individuals with prediabetes. The findings reveal a significant negative association between thiols levels (r = -0.38, p < 0.0001) and the CASS values, while a positive association is observed between chemerin levels (r = 0.47, p < 0.0001) and the CASS values. Linear regression analysis identified chemerin and thiols as independent variables significantly associated with CASS values. Subsequent mediation analysis elucidated that thiols levels act as mediators in the relationship between elevated chemerin levels and an increased CASS value. This study shows that poor cardiovascular function, higher chemerin levels, and reduced antioxidant capacity coexist in individuals with T2DM and prediabetes. Mediation analysis suggests a pathophysiological link between high chemerin levels and low antioxidant capacity, adversely impacting CAN severity.

Excessive daytime napping independently associated with decreased insulin sensitivity in cross-sectional study - Hyogo Sleep Cardio-Autonomic Atherosclerosis cohort study

Background

Although excessive daytime napping has been shown to be involved in diabetes occurrence, its impact on insulin secretion and sensitivity has not been elucidated. It is speculated that excessive napping disrupts the sleep-wake rhythm and increases sympathetic nerve activity during the day, resulting in decreased insulin sensitivity, which may be a mechanism leading to development of diabetes. We previously conducted a cross-sectional study that showed an association of autonomic dysfunction with decreased insulin sensitivity, though involvement of autonomic function in the association between napping and insulin sensitivity remained unclear. Furthermore, the effects of napping used to supplement to short nighttime sleep on insulin secretion and sensitivity are also unknown. In the present cross-sectional study, we examined the relationships of daytime nap duration and autonomic function with insulin secretion and sensitivity in 436 subjects enrolled in the Hyogo Sleep Cardio-Autonomic Atherosclerosis (HSCAA) Cohort Study who underwent a 75-g oral glucose tolerance test (75-g OGTT), after excluding those already diagnosed with diabetes.

Methods

Daytime nap duration was objectively measured using actigraphy, with the subjects divided into the short (≤1 hour) and long (>1 hour) nap groups. Insulin secretion and sensitivity were determined using 75-g OGTT findings. Standard deviation of normal to normal R-R interval (SDNN), a measure of autonomic function, was also determined based on heart rate variability. Subgroup analysis was performed for the associations of napping with insulin secretion and sensitivity, with the results stratified by nighttime sleep duration of less or greater than six hours.

Results

Subjects in the long nap group exhibited lower insulin sensitivity parameters (QUICKI: β=-0.135, p<0.01; Matsuda index: β=-0.119, p<0.05) independent of other clinical factors. In contrast, no associations with insulin secretion were found in either group. Furthermore, the association of long nap duration with insulin sensitivity was not confounded by SDNN. Specific subgroup analyses revealed more prominent associations of long nap habit with lower insulin sensitivity in subjects with a short nighttime sleep time (β=-0.137, p<0.05).

Conclusion

Long daytime nap duration may be a potential risk factor for decreased insulin sensitivity.

Association of Serum Leptin and Adiponectin Concentrations with Type 2 Diabetes Biomarkers and Complications Among Saudi Women

Objective

Hyperglycemia and insulin resistance (IR) put obese women with Type 2 diabetes mellitus (T2DM) at risk for cardiovascular disease (CVD).

Methods

150 T2DM women aged 30-45 were studied cross-sectionally at Madinah Hospital lab to find T2DM risk factors and their association with adiponectin/leptin levels.

Results

Women with T2DM showed greater fasting blood glucose (FBG), hemoglobin A1c (HbA1c), triglycerides (TG), body mass index (BMI), waist circumference (WC), insulin resistance (IR), high-sensitivity C-reactive protein (hs-CRP), and CVD risk (high atherogenic index of plasma (AIP) and leptin), but decreased high-density lipoprotein (HDL-cholesterol) and poor insulin sensitivity with low adiponectin. Obese women with T2DM had increased leptin and reduced adiponectin. Leptin levels were significantly related to IR, BMI, and AIP (B= 3.97, P= 0.02) but not WC. Leptin levels were negatively correlated with insulin sensitivity (IS) and HDL-c (P< 0.05). In linear regression analysis, adiponectin levels had a significant association with IS and HDL-c (P= 0.03, P= 0.04) but an inverse relationship with IR, BMI, WC (B=-2.91, P= 0.04), and AIP (P< 0.05).

Conclusion

Increased leptin levels are related to high IR, AIP, and BMI among T2DM female patients. Similarly, adiponectin levels decrease IS and HDL-c. Therefore, obese T2DM women with high leptin and low adiponectin levels should be periodically checked to avoid or decrease consequences like CVD.

Lower Visceral Fat Area in Patients with Type 2 Diabetic Peripheral Neuropathy

OBJECTIVE

There is preliminary evidence that visceral fat area (VFA) was associated with the presence of type 2 diabetic peripheral neuropathy (DPN) in the Korean population; however, no studies have reported the association in Chinese population. The purpose of this study was to explore the possible correlation of VFA with DPN in such a population.

METHODS

A total of 2498 hospitalized patients with type 2 diabetes mellitus (T2DM) undergone VFA measurement, and were divided into DPN group (n=900) and non-DPN group (n=1594). The association of VFA with the presence of DPN was evaluated by correlation and multiple logistic regression analyses, generalized additive model with a smooth curve fitting, and receiver operating characteristic (ROC) curve analysis.

RESULTS

The VFA was significantly lower in the DPN group than in the non-DPN group (P < 0.001). VFA was significantly and positively associated with sural nerve conduction velocity (SNCV) and amplitude potential (SNAP) and negatively associated with the presence of DPN (all P< 0.001); there was no significant difference in the curve fitting (P = 0.344). Multivariate logistic regression analysis showed that the risk of presence of DPN decreased progressively across the VFA quartiles (P for trend < 0.001) and was significantly lower in patients in the highest VFA quartile than in those in the lowest quartile (OR: 0.382, 95% CI 0.151-0.968, P< 0.001) after multivariate adjustment. The ROC analysis revealed that the best cut-off value of VFA for predicting the presence of DPN was 50.5cm² (sensitivity 84.40%; specificity 34.00%).

CONCLUSION

These results suggest that lower VFA level may be associated with increased risk of the presence of DPN in T2DM patients.

Heart Rate Variability and Cardiovascular Fitness: What We Know so Far

Fluctuation analysis in intervals between heartbeats provides important indices related to autonomic modulation of heart rate variability (HRV). These indices are considered predictors of morbidity and mortality as they are frequently altered in patients with chronic degenerative diseases, especially in those with cardiovascular and metabolic diseases. Similarly, a reduction in HRV is common with aging. In all cases, cardiovascular fitness is often reduced to below the predicted values. In turn, increases in cardiovascular fitness through regular physical exercise, especially aerobic exercise, represent an important therapeutic tool capable of promoting positive adjustments in cardiac autonomic modulation. These adjustments are characterized by reduced sympathetic modulatory influence and/or increased vagal modulatory influence on the heart, increasing the HRV. Therefore, several methodological tools have been used to assess the degree of impairment of autonomic modulation and the therapeutic effects of physical exercise. In contrast, establishment of strict protocols in experimental design is a main challenge in establishing HRV analysis as a robust parameter for evaluating cardiovascular homeostasis. Thus, this review aimed to contribute to the understanding of autonomic modulation of HRV and its relationship with cardiovascular fitness, highlighting the advances made thus far, the applicability of analysis tools, and the confounding factors observed frequently.

Association between adiponectin-to-leptin ratio and heart rate variability in new-onset paroxysmal atrial fibrillation: A retrospective cohort study

Background

The adiponectin‐to‐leptin (A/L) ratio has been identified as a potential surrogate biomarker for metabolic disorders. However, it remains unknown whether the serum A/L ratio is associated with heart rate variability in paroxysmal atrial fibrillation (AF).

Methods

For this retrospective study, we included consecutive patients who underwent 24‐h long‐range electrocardiogram examination in our center for paroxysmal AF. The results of echocardiography, heart rate variability tests, and blood tests were also retrieved. Multivariate line regression analysis was performed to evaluate identify factors independently associated with heart rate variability.

Results

Among the 85 included patients with paroxysmal AF, the median A/L ratio was 1.71. Univariate analysis indicated that patients with a low A/L ratio (<1.71, n = 42) had a lower high‐frequency (HF) power and a higher hs‐CRP level, low‐frequency (LF) power, and LF/HF ratio than those with a high A/L ratio (≥1.71, n = 43). Multivariate linear regression analysis showed that the serum leptin concentration was independently and positively associated with LF (β = 0.175, p = .028), while the serum adiponectin concentration was independently and positively associated with HF (β = 0.321, p = .001). Moreover, the A/L ratio was independently and negatively associated with the LF/HF ratio (β = −0.276, p = .007).

Conclusions

The A/L ratio was independently and negatively associated with the LF/HF ratio in patients with new‐onset paroxysmal AF.

Sleep quality, autonomic dysfunction and renal function in diabetic patients with pre-CKD phase

Diabetes has been established as a strong risk factor for chronic kidney disease (CKD). Sleep apnea, poor sleep quality (PSQ), and autonomic imbalance are also considered to be potential risk factors for decline in renal function, though no known study has examined their integrated predictive value in diabetic and non-diabetic patients without CKD. The present cohort consisted of 754 serial patients (diabetes; n = 231, non-diabetes; n = 523) without CKD registered in the Hyogo Sleep Cardio-Autonomic Atherosclerosis (HSCAA) study. Patients underwent examinations to determine respiratory event index and objective sleep quality using actigraphy, as well as heart rate variability (HRV). Renal outcome was defined as a decline in estimated glomerular filtration rate to less than 60 ml/min/1.73 m² for more than 3 months. Kaplan–Meier analysis showed that diabetic patients with PSQ or low HRV, but not sleep apnea, had a significantly increased risk for renal outcome. Furthermore, Cox proportional hazards analysis revealed that PSQ was significantly associated with elevated risk of renal outcome (HR: 2.57; 95% CI: 1.01–6.53, p = 0.045) independent of sleep apnea and classical risk factors. Low HRV tended to be, but not significantly (p = 0.065), associated with the outcome. In non-diabetic patients, PSQ was also significantly and independently associated with renal outcome, whereas sleep apnea and low HRV were not. In conclusion, PSQ and low HRV appear to be important predictors of decline in renal function in diabetic patients without CKD.

Does bariatric surgery improve cardiac autonomic modulation assessed by heart rate variability? A systematic review

Our study aimed to explore the influence of bariatric surgery (BS) on heart rate (HR) variability (HRV) through a systematic review. Manuscripts were selected based on electronic searches of the MEDLINE, EMBASE, and CINAHL databases from the inception of each database up to year 2020, and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Searching of these studies was systematized using the Population Intervention Comparison Outcome Study Design strategy. We selected randomized and nonrandomized controlled trials and cohorts from prospective studies that reported the influence of BS on HRV. We assessed the quality rating using the Black and Downs questionnaire. Following the screening and eligibility stages, 14 studies were included in the review. All studies agreed that BS promotes an increase in parasympathetic HR control and HRV and a decrease in HR. Yet the literature does not provide evidence that these outcomes are directly caused by the surgical procedure. There is limited evidence to support that patients with type 2 diabetes have greater improvement in HRV as an interim measure, to individuals without. The decrease in insulin resistance was correlated with the increase in HRV in some studies, but, other studies are unsupportive of this outcome. Improvements in 2 metabolic parameters (e.g., leptin, N-terminal pro B-type natriuretic peptide) were connected with superior increases in HRV. This review demonstrated that BS promotes an increase in HRV, indicating improved autonomic control of HR.

Cardiac Autonomic Neuropathy: A Progressive Consequence of Chronic Low-Grade Inflammation in Type 2 Diabetes and Related Metabolic Disorders

Cardiac autonomic neuropathy (CAN) is one of the earliest complications of type 2 diabetes (T2D), presenting a silent cause of cardiovascular morbidity and mortality. Recent research relates the pathogenesis of cardiovascular disease in T2D to an ensuing chronic, low-grade proinflammatory and pro-oxidative environment, being the hallmark of the metabolic syndrome. Metabolic inflammation emerges as adipose tissue inflammatory changes extending systemically, on the advent of hyperglycemia, to reach central regions of the brain. In light of changes in glucose and insulin homeostasis, dysbiosis or alteration of the gut microbiome (GM) emerges, further contributing to inflammatory processes through increased gut and blood-brain barrier permeability. Interestingly, studies reveal that the determinants of oxidative stress and inflammation progression exist at the crossroad of CAN manifestations, dictating their evolution along the natural course of T2D development. Indeed, sympathetic and parasympathetic deterioration was shown to correlate with markers of adipose, vascular, and systemic inflammation. Additionally, evidence points out that dysbiosis could promote a sympatho-excitatory state through differentially affecting the secretion of hormones and neuromodulators, such as norepinephrine, serotonin, and γ-aminobutyric acid, and acting along the renin-angiotensin-aldosterone axis. Emerging neuronal inflammation and concomitant autophagic defects in brainstem nuclei were described as possible underlying mechanisms of CAN in experimental models of metabolic syndrome and T2D. Drugs with anti-inflammatory characteristics provide potential avenues for targeting pathways involved in CAN initiation and progression. The aim of this review is to delineate the etiology of CAN in the context of a metabolic disorder characterized by elevated oxidative and inflammatory load.

Leptin mediate central obesity on the severity of cardiovascular autonomic neuropathy in well-controlled type 2 diabetes and prediabetes

BACKGROUND

Evidences support the view that central obesity is an independently cardiovascular risk. It is thought that leptin contributes to autonomic dysfunction and cardiovascular risks in type 1 and type 2 diabetes mellitus (T1DM and T2DM). This raises the possibility that leptin might mediate the relationship between central obesity and the severity of cardiovascular autonomic neuropathy (CAN) in patients with well-controlled T2DM and prediabetes.

METHODS

The complete cardiovascular reflex tests and biomarkers were assessed for each patient. The severity of CAN was assessed using composite autonomic scoring scale (CASS). A single-level three-variable mediation model was used to investigate the possible relationships among central obesity [as indicated by waist circumference (WC)], leptin level, and severity of CAN (as indicated by CASS value).

RESULTS

A total of 107 patients were included in this study: 90 with diabetes and 17 with prediabetes. The results demonstrate that increased WC is associated with increased severity of CAN (r = 0.242, P = 0.017). We further discovered that leptin level is positively correlated with WC (r = 0.504, P < 0.0001) and the CASS value (r = 0.36, P < 0.0001). Further mediation analysis shows that leptin level serves as mediators between higher WC and higher CASS.

CONCLUSIONS

Our results highlighted the relationship among leptin, central obesity, and severity of CAN. As the leptin level serves as mediator between central obesity and severity of CAN, a longitudinal study is needed to confirm that control of WC can decrease leptin levels and can be effective in reducing CAN progression.

Cardiovascular autonomic neuropathy in patients with type 2 diabetes mellitus and its association with serum omentin and leptin

Cardiovascular autonomic neuropathy (CAN) is a major cause of morbidity and mortality in patients with diabetes as it is associated with a high risk of cardiac arrhythmias.

Subclinical decrease in cardiac autonomic and diastolic function in patients with metabolic disorders: HSCAA study

Heart failure due to decreased diastolic function, HFpEF, is a growing health concern with rising prevalence. We examined subclinical cardiac autonomic and diastolic functions in 605 patients with metabolic diseases classified as pre-heart failure. Presence of glucose intolerance or diabetes, or visceral adiposity was significantly associated with reduced cardiac autonomic and diastolic functions. Higher autonomic functions were significantly associated with a parameter of better cardiac diastolic function (E/A) (SDNN: r = 0.306, p < 0.01; HF: r = 0.341, p < 0.01), with the association independent of diabetes, body mass index, visceral adiposity and insulin resistance index. Thus, reduced autonomic function may be a potential predictor for decreased cardiac diastolic functions in metabolic disorders.

•

Metabolic disorders, including diabetes and obesity, are known risk factors for HFpEF.

•

Reduced autonomic function may be involved in pathogenesis of HFpEF.

•

Cardiac diastolic function in metabolic disorders in pre-HF phase is not well examined.

•

In pre-HF subjects, reduced autonomic function is associated with lower cardiac diastolic functions.

•

Our findings provide new insights into HFpEF etiology in metabolic disorders.

Associations of sleep quality, sleep apnea and autonomic function with insulin secretion and sensitivity: HSCAA study

RATIONALE AND PURPOSE

Although sleep disorders are shown to be involved in occurrence of diabetes, impacts of several quantitative parameters related to sleep on insulin secretion and sensitivity is yet to be elucidated. We cross-sectionally examined relationships among quantitative sleep quality, sleep apnea, and autonomic function with insulin secretion and sensitivity in 399 patients without previous diagnosed diabetes who underwent 75-g oral glucose tolerance test (75gOGTT).

METHOD

Poor sleep quality (PSQ) was defined as an activity index ≥50 by actigraphy. Sleep apnea was measured by apnomonitor, while standard deviation of all normal-to-normal R-R intervals (SDNN) was measured by active tracer. Parameters of insulin secretion and sensitivity were measured by 75gOGTT.

RESULTS

Patients with PSQ exhibited significantly lower insulinogenic index (r = 0.155, p < 0.01), a parameter of insulin secretion, with the association independent of other clinical factors including apnea and SDNN (β = -0.156, p < 0.01). In contrast, presence of sleep apnea (r = -0.143, p < 0.05) and the lower SDNN (r = -0.150, p < 0.01) were significantly and inversely associated with BIGTT-S, an insulin sensitivity parameter, with the association of SDNN with BIGTT-S remaining significant even after adjustments for PSQ and sleep apnea (β = -0.111, p < 0.05).

CONCLUSION

Poor sleep quality is an independent predictor of pancreatic β-cell function, which could be involved in occurrence of type 2 diabetes.

Inverse association of plasma leptin with cortical thickness at distal radius determined with a quantitative ultrasound device in patients with type 2 diabetes mellitus

AIMS/INTRODUCTION

Osteoporosis is known to be intimately related to sympathetic nerve activity. We examined the relationship of plasma leptin with cortical and trabecular bone components in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

The present cross-sectional study included 182 type 2 diabetes mellitus patients (93 men, 89 women). Cortical thickness (CoTh) and trabecular bone mineral density (BMD) were determined at the 5.5% distal radius using an LD-100 ultrasonic bone densitometry device. Plasma leptin along with physical and laboratory measurements was simultaneously determined.

RESULTS

Plasma leptin, but not body mass index (BMI), was inversely correlated with CoTh (ρ = -0.487, P < 0.001), while BMI, but not plasma leptin, was positively correlated with trabecular BMD (ρ = 0.369, P < 0.001). In multivariable regression analysis, after adjustments for age, sex, duration of diabetes, glycated hemoglobin A1c, albumin, estimated glomerular filtration rate, parathyroid hormone and handgrip strength, plasma leptin was inversely associated with CoTh (β = -0.258, P < 0.001), but not trabecular BMD. Furthermore, plasma leptin level retained a significant association with CoTh after further adjustment for BMI (β = -0.237, P < 0.001) and BMI plus waist-to-hip ratio (β = -0.243, P < 0.001). In contrast, the "sex × leptin" interaction was not significant (P = 0.596).

CONCLUSIONS

Leptin level in plasma, independent of BMI and BMI plus waist-to-hip ratio, was shown to be inversely associated with CoTh, but not trabecular BMD, suggesting that hyperleptinemia resulting from obesity might contribute to cortical porosis in patients with type 2 diabetes mellitus.

New Insights into Adipokines as Potential Biomarkers for Type-2 Diabetes Mellitus

A large number of studies have been focused on investigating serum biomarkers associated with risk or diagnosis of type-2 diabetes mellitus. In the last decade, promising studies have shown that circulating levels of adipokines could be used as a relevant biomarker for diabetes mellitus progression as well as therapeutic future targets. Here, we discuss the possible use of recently described adipokines, including apelin, omentin-1, resistin, FGF-21, neuregulin-4 and visfatin, as early biomarkers for diabetes. In addition, we also include recent findings of other well known adipokines such as leptin and adiponectin. In conclusion, further studies are needed to clarify the pathophysiological significance and clinical value of these biological factors as potential biomarkers in type-2 diabetes and related dysfunctions.

Correlation of C1q/TNF-Related Protein-3 with Cardiac Autonomic Tone and Metabolic Parameters in Obesity

OBJECTIVES

The current study aimed at investigating the correlation of circulating levels of serum C1q/TNF-related protein-3 (CTRP3) with cardiac autonomic functions and metabolic parameters in obesity.

METHODS

Thirty drug naïve subjects newly diagnosed with obesity and body mass index (BMI) 25 - 35 kg/m² of both genders aged 19 - 40 years, with no associated comorbidity were recruited as cases. Same number of age, gender and socioeconomic status matched subjects with BMI 19 - 23 kg/m² were taken as controls. Autonomic function test results including heart rate variability (HRV) were recorded in both groups. Serum metabolic parameters -CTRP3, leptin, adiponectin, insulin, blood glucose, glycated hemoglobin (HbA1c), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol, and triglycerides were also determined and compared between the groups.

RESULTS

Significantly lower circulating levels of CTRP3 (P ≤ 0.001) and adiponectin (P = 0.025), and significantly higher mean of BMI (P < 0.001), fasting blood glucose (P < 0.001), LDL-cholesterol (P < 0.05), serum triglycerides (P < 0.001), insulin (P = 0.003), HOMA-IR (homeostasis model assessment of insulin resistance) (P < 0.001), and leptin (P = 0.043) were observed in the group with obesity compared to the controls. CTRP3 levels inversely correlated with serum triglyceride (r = -0.09, P < 0.001), atherogenic index (r = -0.37, P = 0.04), leptin (r = -0.39, P = 0.02), and positively with adiponectin (r = 0.42, P = 0.02) in the group with obesity. Significant reduction in the results of parasympathetic autonomic function tests (pNN50, RMSSD, excitation: inhibition (E:I) ratio, 30:15 ratio, and Valsalva ratio) and an increase in sympathovagal balance (low frequency to high frequency (LF:HF) ratio) was also observed (P < 0.05). CTRP3 levels were also positively correlated with parasympathetic indices (pNN50: r = 0.17, P < 0.05); 30:15 ratio: (r = 0.62, P < 0.01), and inversely correlated with LF: HF ratio (r = -0.35, P < 0.01) in the group with obesity.

CONCLUSIONS

Higher circulating levels of CTRP3 promoted a favorable autonomic and metabolic profile in obesity. Hence, CTRP3 may be considered as a potential novel biomarker to facilitate the prognosis of obesity and its comorbidities.

Sleep, Autonomic Nervous Function and Atherosclerosis

Behavioral and psychosocial factors related to development of cardiovascular disease have been gaining increased attention. Notably, sleep is considered to be one of the most important behavioral factors involved in progression of atherosclerosis and cardiovascular events, with autonomic nervous function a potential mechanism. Several studies have shown associations of sleep and autonomic dysfunction with major surrogate markers of atherosclerosis, such as carotid intima-media thickness and arterial stiffness. Endocrinological, immunological, oxidative, inflammatory, and metabolic responses, as well as endothelial dysfunction may mediate the effects of the autonomic nervous system. For this review, we examined recent findings related to sleep, autonomic nervous dysfunction, and atherosclerosis, with the aim of understanding the involved pathophysiological mechanisms.

Cancer and comorbidity: The role of leptin in breast cancer and associated pathologies

Obesity is an important risk factor for postmenopausal breast cancer and also a poor prognostic factor among cancer patients. Moreover, obesity is associated with a number of health disorders such as insulin resistance/type-2 diabetes mellitus, hypertension, and other cardiovascular diseases. Frequently, these health disorders exhibit as components/complications of the metabolic syndrome. Nevertheless, obesity-related diseases may coexist with postmenopausal breast cancer; and these comorbid conditions could be substantial. Therefore, it may be assumed that different diseases including breast cancer could originate from a common pathological background in excessive adipose tissue. Adipocyte-released hormone-like cytokine (or adipokine) leptin behaves differently in a normal healthy state and obesity. A growing body of evidence suggests an important role of leptin in our major obesity-related health issues such as insulin resistance, hypertension, and neoplasia. In this context, this review describes the relationships of the abovementioned pathologies with leptin.

Leptin, cardiovascular diseases and type 2 diabetes mellitus

Leptin, an adipokine that is implicated in the control of food intake via appetite suppression, may also stimulate oxidative stress, inflammation, thrombosis, arterial stiffness, angiogenesis and atherogenesis. These leptin-induced effects may predispose to the development of cardiovascular diseases. In the present review we discuss the evidence linking leptin levels with the presence, severity and/or prognosis of both coronary artery disease and non-cardiac vascular diseases such as stroke, carotid artery disease, peripheral artery disease (PAD) and abdominal aortic aneurysms (AAA) as well as with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). Leptin levels have been positively associated with the presence, severity, extent and lesion complexity of coronary atherosclerosis as well as with the presence, severity and poor clinical outcomes of both ischemic and hemorrhagic strokes. But conflicting results also exist. Furthermore, leptin was reported to independently predict common carotid intima-media thickness and carotid plaque instability. A link between hyperleptinemia and PAD has been reported, whereas limited data were available on the potential association between leptin and AAA. Elevated leptin concentrations have also been related to CKD incidence and progression as well as with insulin resistance, T2DM, micro- and macrovascular diabetic complications. Statins and antidiabetic drugs (including sitagliptin, metformin, pioglitazone, liraglutide and empagliflozin) may affect leptin levels. Further research is needed to establish the potential use (if any) of leptin as a therapeutic target in these diseases.

Correlation between CH2DS2-VASc Score and Serum Leptin Levels in Cardioembolic Stroke Patients: The Impact of Metabolic Syndrome

OBJECTIVE

To determine adipokines levels in patients with different etiologic subtypes of acute ischemic stroke (AIS) and metabolic syndrome (MetS) status.

METHODS

Serum adiponectin, leptin, and resistin levels were determined by ELISA in 99 AIS patients and 59 stroke-free control group subjects. Stroke patients were grouped based on MetS, modified TOAST classification, and CHA2DS2-VASc scale in case of cardioembolic stroke following atrial fibrillation.

RESULTS

No differences were found in all adipokine serum levels between AIS patients and appropriately matched control group. MetS-AIS patients had significantly higher leptin levels (22.71 ± 19.01 ng/ml versus 8.95 ± 9.22 ng/ml, p < 0.001) and lower adiponectin levels (10.71 ± 8.59 ng/ml versus 14.93 ± 10.95 ng/ml, p < 0.05) than non-MetS-AIS patients. In patients with cardioembolic stroke, leptin levels were significantly higher than in remaining stroke cases (19.57 ± 20.53 ng/ml versus 13.17 ± 12.36 ng/ml, p < 0.05) and CHA2DS2-VASc score positively correlated with leptin levels only (p < 0.001). Analysis of individual components of CHA2DS2-VASc score showed that hypertension, female gender, and diabetes had greatest impact on elevated serum leptin level.

CONCLUSION

This pilot study revealed that leptin could be a potential biomarker for risk stratification of cardioembolic stroke in MetS patients and that heterogeneity of stroke subtypes should be considered for more refined and precise clinical stroke studies.

α-Glucosidase inhibitor miglitol attenuates glucose fluctuation, heart rate variability and sympathetic activity in patients with type 2 diabetes and acute coronary syndrome: a multicenter randomized controlled (MACS) study

Background

Little is known about clinical associations between glucose fluctuations including hypoglycemia, heart rate variability (HRV), and the activity of the sympathetic nervous system (SNS) in patients with acute phase of acute coronary syndrome (ACS). This pilot study aimed to evaluate the short-term effects of glucose fluctuations on HRV and SNS activity in type 2 diabetes mellitus (T2DM) patients with recent ACS. We also examined the effect of suppressing glucose fluctuations with miglitol on these variables.

Methods

This prospective, randomized, open-label, blinded-endpoint, multicenter, parallel-group comparative study included 39 T2DM patients with recent ACS, who were randomly assigned to either a miglitol group (n = 19) or a control group (n = 20). After initial 24-h Holter electrocardiogram (ECG) (Day 1), miglitol was commenced and another 24-h Holter ECG (Day 2) was recorded. In addition, continuous glucose monitoring (CGM) was performed throughout the Holter ECG.

Results

Although frequent episodes of subclinical hypoglycemia (≤4.44 mmo/L) during CGM were observed on Day 1 in the both groups (35% of patients in the control group and 31% in the miglitol group), glucose fluctuations were decreased and the minimum glucose level was increased with substantial reduction in the episodes of subclinical hypoglycemia to 7.7% in the miglitol group on Day 2. Holter ECG showed that the mean and maximum heart rate and mean LF/HF were increased on Day 2 in the control group, and these increases were attenuated by miglitol. When divided 24-h time periods into day-time (0700–1800 h), night-time (1800–0000 h), and bed-time (0000–0700 h), we found increased SNS activity during day-time, increased maximum heart rate during night-time, and glucose fluctuations during bed-time, which were attenuated by miglitol treatment.

Conclusions

In T2DM patients with recent ACS, glucose fluctuations with subclinical hypoglycemia were associated with alterations of HRV and SNS activity, which were mitigated by miglitol, suggesting that these pathological relationships may be a residual therapeutic target in such patients.

Trial registration Unique Trial Number, UMIN000005874 (https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000006929)

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-017-0571-1) contains supplementary material, which is available to authorized users.

Plasma brain-derived neurotrophic factor concentration is a predictor of chronic kidney disease in patients with cardiovascular risk factors - Hyogo Sleep Cardio-Autonomic Atherosclerosis study

Background

Brain-derived neurotrophic factor (BDNF) has been shown to have protective effects against cardiovascular diseases and death through neural and non-neural pathways via tropomyosin-related kinase B signaling. However, it is not known whether plasma BDNF concentration is a predictor of chronic kidney disease (CKD).

Design

This study was conducted as a prospective cohort study as part of the Hyogo Sleep Cardio-Autonomic Atherosclerosis.

Methods

We measured plasma BDNF concentration in 324 patients without CKD, defined as an estimated glomerular filtration rate (eGFR) less than 60 ml/min/1.73m², and with cardiovascular risk factors. As potential confounders, sleep condition, nocturnal hypertension, and autonomic function were quantitatively examined. The patients were followed for a median 37 months (range 2–59 months) and occurrence of CKD was noted.

Results

Plasma BDNF concentration was significantly and independently associated with CKD development, which occurred in 38 patients (11.7%). Kaplan-Meier analysis revealed that patients with reduced plasma BDNF concentration exhibited a significantly (p = 0.029) greater number of CKD events as compared to those with a higher concentration. Moreover, comparisons of key subgroups showed that the risk of CKD in association with low plasma BDNF concentration was more prominent in patients with a greater reduction of nocturnal systolic blood pressure, better movement index, higher standard deviations of the NN(RR) interval or average NN(RR) interval for each 5-minute period, and without past cardiovascular disease events, smoking habit, or albuminuria.

Conclusions

Plasma BDNF concentration is an independent predictor for development of CKD in patients with cardiovascular risk factors.

Caracterização da variabilidade da frequência cardíaca em indivíduos com síndrome metabólica

RESUMO Introdução: A variabilidade da frequência cardíaca (VFC) tem sido considerada um mecanismo de modulação do sistema nervoso autônomo. A diminuição da VFC pode estar associada à síndrome metabólica (SM). Objetivo: Comparar a VFC e variáveis de saúde em indivíduos com e sem SM. Métodos: Cento e dezenove participantes foram divididos em dois grupos: sem SM (SSM, n = 68) e com SM (CSM, n = 51). Foi avaliada a análise espectral da VFC em repouso, durante teste cardiopulmonar de exercício (TCPE) e na recuperação em bandas de baixa frequência (LF = 0,04-0,15 Hz), alta frequência (HF = 0,15-0,4 Hz) e razão LF/HF. Adicionalmente, a frequência cardíaca (FC) de repouso (FCrep), FC máxima (FCmáx), pressão arterial sistólica (PAS) e diastólica (PAD), glicemia, perfil lipídico, consumo de oxigênio pico (VO2pico) e composição corporal foram avaliados. Resultados: A FCrep e o VO2pico não apresentaram diferenças entre o CSM e o SSM (73,3 ± 9,1 vs. 70,1 ± 11,0 bpm) (26,8 ± 4,6 vs. 28,1 ± 6,6 ml.kg-1.min-1), respectivamente. A VFC foi similar entre os grupos nos diferentes momentos analisados. A glicemia (99,8 ± 22,5 vs. 87,6 ± 8,6 mg/dl) foi superior no CSM comparado ao SSM. Os valores de triglicérides (159,5 ± 68,8 vs. 89,2 ± 34,3 mg/dl) e VLDL-c (31,9 ± 13,8 vs. 17,8 ± 6,9 mg/dl) foram superiores no CSM comparado ao SSM. O HDL-c (40,7 ± 11,5 vs. 49,3 ± 9,8 mg/dl) foi menor no CSM comparado ao SSM. O IMC (33,1 ± 4,7 vs. 30,8 ± 3,8 Kg/m²) foi superior no CSM comparado ao SSM. A PAS (128,6 ± 12,9 vs. 119,5 ± 11,3 mmHg) e a PAD (77,2 ± 10,5 vs. 72,9 ± 8,1 mmHg) foram superiores no CSM comparado ao SSM, p < 0,05. Conclusão: Os resultados sugerem que a presença de SM não é suficiente para provocar alterações nos índices de VFC em repouso, durante teste cardiopulmonar de exercício (TCPE) e na recuperação quando os pacientes são comparados a indivíduos sem a doença.

Leptin as a Mediator of Obesity-Induced Hypertension

Hypertension and associated cardiovascular diseases represent the most common health complication of obesity and the leading cause of morbidity and mortality in overweight and obese patients. Emerging evidence suggests a critical role for the central nervous system particularly the brain action of the adipocyte-derived hormone leptin in linking obesity and hypertension. The preserved ability of leptin to cause cardiovascular sympathetic nerve activation despite the resistance to the metabolic actions of the hormone appears essential in this pathological process. This review describes the evidence supporting the neurogenic bases for obesity-associated hypertension with a particular focus on the neuronal and molecular signaling pathways underlying leptin's effects on sympathetic nerve activity and blood pressure.

Plasma leptin concentration is associated with fatigue severity in patients with cardiovascular risk factors - HSCAA study

Fatigue induced by complex dysfunctions of the central nervous system is frequently complained by patients with cardiovascular risk factors. Although leptin is considered to regulate the central nervous system, there are no reports regarding its association with fatigue in those patients. This cross-sectional study included 347 patients with cardiovascular risk factors. Fatigue score and plasma leptin concentration were measured. In addition, abdominal fat accumulation, systemic inflammation, sleep condition, and functions of hypothalamus-pituitary axis and autonomic system were estimated. Plasma leptin concentration (natural logarithm transformed) was significantly and positively (r=0.222, p<0.001) associated with fatigue score, and significantly (p<0.001) higher in the moderately-fatigued group (2.32±0.75ng/ml, mean±SD, n=52) than in the normally-fatigued group (1.85±1.02ng/ml, mean±SD, n=295). Multiple logistic regression analysis showed that plasma leptin concentration was significantly and independently associated with a moderately-fatigued condition independent of other factors, including age, gender, presence of diabetes, hypertension, dyslipidemia, alcohol consumption habit, urinary free cortisol, serum high-sensitive CRP concentration, visceral and subcutaneous fat area, apnea/hypopnea index, sleep efficiency, and heart rate variability. Hyperleptinemia may contribute to fatigue severity in patients with cardiovascular risk factors.

Developmental Origins of Cardiometabolic Diseases: Role of the Maternal Diet

Developmental origins of cardiometabolic diseases have been related to maternal nutritional conditions. In this context, the rising incidence of arterial hypertension, diabetes type II, and dyslipidemia has been attributed to genetic programming. Besides, environmental conditions during perinatal development such as maternal undernutrition or overnutrition can program changes in the integration among physiological systems leading to cardiometabolic diseases. This phenomenon can be understood in the context of the phenotypic plasticity and refers to the adjustment of a phenotype in response to environmental input without genetic change, following a novel, or unusual input during development. Experimental studies indicate that fetal exposure to an adverse maternal environment may alter the morphology and physiology that contribute to the development of cardiometabolic diseases. It has been shown that both maternal protein restriction and overnutrition alter the central and peripheral control of arterial pressure and metabolism. This review will address the new concepts on the maternal diet induced-cardiometabolic diseases that include the potential role of the perinatal malnutrition.

Alterations in heart rate variability during everyday life are linked to insulin resistance. A role of dominating sympathetic over parasympathetic nerve activity?

AIMS

To evaluate the role of the autonomic nervous system (ANS) in the development of insulin resistance (IR) and assess the relationship between IR and activity of ANS using power spectrum analysis of heart rate variability (HRV).

SUBJECTS AND METHODS

Twenty-three healthy first-degree relatives of patients with type 2 diabetes (R) and 24 control subjects without family history of diabetes (C) group-matched for age, BMI and sex were included. Insulin sensitivity (M value) was assessed by hyperinsulinemic (56 mU/m(2)/min) euglycemic clamp. Activity of the ANS was assessed using power spectrum analysis of HRV in long-term recordings, i.e., 24-h ECG monitoring, and in short-term recordings during manoeuvres activating the ANS. Computed tomography was performed to estimate the amount and distribution of abdominal adipose tissue.

RESULTS

Insulin sensitivity (M value, mg/kg lbm/min) did not differ significantly between the R and C groups. Total spectral power (Ptot) and very low-frequency (PVLF) power was lower in R than C during 24 h ECG-recordings (p = 0.02 and p = 0.03). The best fit multiple variable linear regression model (r(2) = 0.37, p < 0.001 for model) indicated that body composition (BMI) and long-term low to high frequency (LF/HF) power ratio (std β = -0.46, p = 0.001 and std β = -0.28, p = 0.003, respectively) were significantly and independently associated with the M value.

CONCLUSION

Altered heart rate variability, assessed by power spectrum analysis, during everyday life is linked to insulin resistance. The data suggest that an increased ratio of sympathetic to parasympathetic nerve activity, occurring via both inherited and acquired mechanisms, could potentially contribute to the development of type 2 diabetes.

Low birth weight leads to obesity, diabetes and increased leptin levels in adults: the CoLaus study

BACKGROUND

Low birth weight is associated with increased rates of obesity, insulin resistance and type 2 diabetes, but the precise mechanisms for this association remain unclear. We aimed to assess the relationships between birth weight and markers of glucose homeostasis or obesity in adults.

METHODS

Cross-sectional population-based study on 1458 women and 1088 men aged 35-75 years living in Lausanne, Switzerland. Birth weight was self-reported and categorized into ≤ 2.5, 2.6-3.5, 3.6-4.0 and >4.0 kg. Body composition was assessed by bioimpedance. Leptin and adiponectin levels were measured by ELISA.

RESULTS

Women with low birth weight (≤ 2.5 kg) had higher levels of fasting plasma glucose, insulin, HOMA, diabetes and metabolic syndrome; a non significant similar trend was seen in men. In both genders, height increased with birth weight, whereas a U-shaped association was found between birth weight and body mass index, waist circumference and body fat percentage. After adjusting for age, smoking status, physical activity and fat mass, an inverse association was found between leptin and birth weight categories: adjusted mean ± standard error 17.3 ± 0.7, 16.2 ± 0.3, 15.6 ± 0.5 and 14.0 ± 0.8 ng/dL for birth weight categories ≤ 2.5, 2.6-3.5, 3.6-4.0 and >4.0 kg, respectively, in women (p < 0.05) and 9.8 ± 0.8, 9.1 ± 03, 7.8 ± 0.4 and 7.7 ± 0.5 ng/dL in men (p < 0.05). An inverse association was also found between reported birth weight and leptin to fat mass ratio: mean ± standard error 0.77 ± 0.04, 0.73 ± 0.02, 0.69 ± 0.03 and 0.62 ± 0.04 in women (p < 0.05); 0.46 ± 0.05, 0.45 ± 0.02, 0.39 ± 0.02 and 0.38 ± 0.03 in men (p < 0.05). No differences in adiponectin levels were found between birth weight groups.

CONCLUSIONS

Middle-aged adults born with a low weight present a higher prevalence of diabetes and obesity and also higher leptin levels and leptin to fat mass ratio than adults born with a normal weight. The higher leptin levels and leptin to fat mass ratio among adults born with a low weight might be related to nutritional factors during childhood or to the development of leptin resistance and/or higher leptin production by body fat unit. Subjects born with a low weight should be counselled regarding the risks of developing diabetes and/or cardiovascular disease.

Impact of metabolic syndrome and its components on heart rate variability during hemodialysis: a cross-sectional study

Background

Both uremia and metabolic syndrome (MetS) affect heart rate variability (HRV) which is a risk factor of poor prognoses. The aim of this study was to evaluate the impact of MetS on HRV among chronic hemodialysis patients.

Methods

This cross-sectional study was carried out in a teaching hospital in Northern Taiwan from June to August, 2010. Adult patients on chronic hemodialysis without active medical conditions were enrolled. HRV were measured for 4 times on the index hemodialysis day (HRV-0, -1, -2, and -3 at before, initial, middle, and late phases of hemodialysis, respectively), and the baseline demographic data and clinical parameters during the hemodialysis session were documented. Then we evaluated the impacts of MetS and its five components on HRV.

Results

One hundred and seventy-five patients (100 women, mean age 65.1 ± 12.9 years) were enrolled and included those with MetS (n = 91, 52 %) and without MetS (n = 84, 48 %). The patients with MetS(+) had significantly lower very low frequency, total power, and variance in HRV-0, total power and variance in HRV-2, and variance in HRV-3. (all p ≦ 0.05) When using the individual components of MetS to evaluate the impacts on HRV indices, the fasting plasma glucose (FPG) criterion significantly affected most indices of HRV while other four components including “waist circumference”, “triglycerides”, “blood pressure”, and “high-density lipoprotein” criteria exhibited little impacts on HRV. FPG criterion carried the most powerful influence on cardiac ANS, which was even higher than that of MetS. The HRV of patients with FPG(+) increased initially during the hemodialysis, but turned to decrease dramatically at the late phase of hemodialysis.

Conclusions

The impact of FPG(+) outstood the influence of uremic autonomic dysfunction, and FPG criterion was the most important one among all the components of MetS to influence HRV. These results underscored the importance of interpretation and management for abnormal glucose metabolism.