Aerobic exercise training-induced changes in serum adropin level are associated with reduced arterial stiffness in middle-aged and older adults

Egg intake in relation to metabolic health status, serum brain derived neurotrophic factor, and adropin levels in Iranian adults

There is conflicting information about the association between egg intake and metabolic health status and no previous information on this association was found in Middle Eastern populations. This research aimed to investigate the relationship between egg consumption and metabolic health status in Iranian adults, focusing on the potential involvement of brain-derived neurotrophic factor (BDNF) and adropin. This cross-sectional study was done on a sample of 527 individuals (45.7% female) aged between 20 and 65 years. Participants were selected using a multistage cluster random-sampling method. Dietary intakes of participants were evaluated using a validated food frequency questionnaire. Blood samples were collected while the individuals were fasting to assess biochemical markers. Metabolic health status of individuals was assessed based on the criteria established by Wildman. Collecting data on covariates was done using pre-tested procedures. Multivariable-adjusted model revealed a statistically significant association between egg consumption and a decreased odds of metabolically unhealthy (MU) status (ORT3 vs. T1 = 0.47; 95%CI 0.24-0.92). Also, each tertile increase in egg consumption was significantly associated with decreased odds of MU status (OR = 0.68; 95%CI 0.49-0.96). This association was especially significant among males rather than females. Elevated high-sensitive C-reactive protein (hs-CRP) levels were substantially reduced among individuals with the highest consumption of egg compared to the lowest intake. Additionally, there was a slight inverse association between egg consumption and high blood pressure. There were no relationships between egg intake and having low BDNF, and adropin levels. Increased consumption of egg was associated with a decreased chance of being metabolically unhealthy in Iranian adults, especially in male participants.

Investigating the Effect of a Multicomponent Exercise Program on Adropin, Endothelial Function, Insulin Resistance, and Sleep Quality in Overweight Older Adults (a Link With Physiological Indexes and Sleep Quality): Results of a Randomized Controlled Study

The aim of the present study was to investigate the effects of multicomponent training on adropin, endothelial function, insulin resistance, and sleep quality in overweight older adults. In this randomized controlled study, 40 overweight older adults were randomly divided into training and control groups. The multicomponent training program including aerobic, resistance, and balance exercise was followed for 8 weeks, 3 days a week. Study variables were measured 48 hr before and after the intervention. After 8 weeks of multicomponent training, adropin (p = .01), nitric oxide (p = .01), and maximal oxygen uptake (VO2max; p = .002) increased, and glucose (p = .001), insulin (p = .001), insulin resistance (p = .01), systolic blood pressure (p = .01), and sleep disorders (p = .01) decreased significantly. Also, Pearson's test results showed a significant inverse relationship between adropin level (p = .01 and r = -.55) and glucose (p = .01 and r = -.51) with sleep disorders. It seems that multicomponent training increases adropin and improves insulin resistance, endothelial function, and sleep quality in older adults.

The effect of 60 days of 6° head-down-tilt bed rest on circulating adropin, irisin, retinol binding protein-4 (RBP4) and individual metabolic responses in young, healthy males

Background

Alterations in the circulating concentrations and target-tissue action of organokines underpin the development of insulin resistance in microgravity and gravity deprivation. The purpose of this study was to examine changes in circulating adropin, irisin, retinol binding protein-4 (RBP4), and the metabolic response of healthy young males following 60 days of 6° head-down-tilt (HDT) bed rest, with and without reactive jump training (RJT), to explore links with whole-body and tissue-specific insulin sensitivity. To our knowledge, this is the first time that adropin, irisin, and RBP4 have been studied in HDT bed rest.

Methods

A total of 23 male subjects (29 ± 6 years, 181 ± 6 cm, 77 ± 7 kg) were exposed to 60 days of 6° HDT bed rest and randomized to a control (CTRL, n = 11) or a RJT (JUMP, n = 12) group (48 sessions with ≤4 min total training time per session). Circulating adropin, irisin, and RBP4 were quantified in fasting serum before and after HDT bed rest. A subanalysis was performed a posteriori to investigate individual metabolic responses post-HDT bed rest based on subjects that showed an increase or decrease in whole-body insulin sensitivity (Matsuda index).

Results

There were significant main effects of time, but not group, for decreases in adropin, irisin, Matsuda index, and liver insulin sensitivity following HDT bed rest (p < 0.05), whereas RBP4 did not change. The subanalysis identified that in a subgroup with decreased whole-body insulin sensitivity (n = 17), RBP4 increased significantly, whereas adropin, irisin, and liver insulin sensitivity were all decreased significantly following HDT bed rest. Conversely, in a subgroup with increased whole-body insulin sensitivity (n = 6), liver insulin sensitivity increased significantly after HDT bed rest, whereas adropin, irisin, and RBP4 did not change.

Conclusion

Investigating individual metabolic responses has provided insights into changes in circulating adropin, irisin, RBP4, in relation to insulin sensitivity following HDT bed rest. We conclude that adropin, irisin, and RBP4 are candidate biomarkers for providing insights into whole-body and tissue-specific insulin sensitivity to track changes in physiological responsiveness to a gravity deprivation intervention in a lean male cohort.

Adropin: A crucial regulator of cardiovascular health and metabolic balance

Adropin, a peptide discovered in 2008, has gained recognition as a key regulator of cardiovascular health and metabolic balance. Initially identified for its roles in energy balance, lipid metabolism, and glucose regulation, adropin has also been found to improve cardiovascular health by enhancing endothelial function, modulating lipid profiles, and reducing oxidative stress. These protective mechanisms suggest that adropin may be able to help prevent conditions such as atherosclerosis, hypertension, and other cardiovascular diseases. Research has established connections between adropin and cardiovascular risk factors, such as obesity, insulin resistance, and dyslipidemia, positioning it as a valuable biomarker for evaluating cardiovascular disease risk. New studies highlight adropin's diagnostic and prognostic significance, showing that higher levels are linked to better cardiovascular outcomes, while lower levels are associated with a higher risk of cardiovascular diseases. This review aims to summarize current knowledge on adropin, emphasizing its significance as a promising focus in the intersection of cardiovascular health and metabolic health. By summarizing the latest research findings, this review aims to offer insights into the potential applications of adropin in both clinical practice and research, leading to a deeper understanding of its role in maintaining cardiovascular and metabolic health.

Dietary intake of methyl donor nutrients in relation to metabolic health status, serum levels of brain-derived neurotrophic factor and adropin

BACKGROUND AND AIMS

There is a lack of evidence on dietary intake of methyl donor nutrients with metabolic health status and related biomarkers. Thus, this study aimed to assess the relation between methyl donor nutrients intake and metabolic health status with regarding the interactive roles of brain-derived neurotrophic factor (BDNF) and adropin in Iranian adults.

METHODS

This cross-sectional survey was conducted among 527 Iranian adults (45.7% female) selected by multistage cluster random-sampling method. A validated food frequency questionnaire was used to evaluate participants' dietary intake. Metabolic unhealthy status was defined by Wildman criteria as having ≥ 2 of hyperglycemia, hypertriglyceridemia, hypo-HDL-cholesterolemia, hypertension, chronic inflammation, and insulin resistance. Concentrations of metabolic parameters, BDNF and adropin were determined using fasting blood samples.

RESULTS

An inverse association was found between methyl donor nutrients intake and metabolically unhealthy status in multivariable-adjusted model (ORT3 vs. T1 = 0.30; 95%CI: 0.12-0.75). This association was especially significant among overweight/obese adults and was stronger in women. Additionally, consumption of vitamin B6 and choline was separately related to reduced odds of metabolically unhealthy status. Methyl donor intake was not significantly related to low BDNF (ORT3 vs. T1 = 0.93; 95%CI: 0.60-1.44) and adropin (ORT3 vs. T1 = 0.71; 95%CI: 0.44-1.15). However, the interaction between high methyl donor nutrients intake and high BDNF was related to lower odds of metabolically unhealthy status in multivariable-adjusted model (ORMDNS∗BDNF = 0.27; 95%CI: 0.11-0.67).

CONCLUSION

Higher intake of methyl donor nutrients, alone and in interaction with BDNF levels, was associated with decreased odds of metabolically unhealthy status in Iranian adults.

Molecular insights of exercise therapy in disease prevention and treatment

Despite substantial evidence emphasizing the pleiotropic benefits of exercise for the prevention and treatment of various diseases, the underlying biological mechanisms have not been fully elucidated. Several exercise benefits have been attributed to signaling molecules that are released in response to exercise by different tissues such as skeletal muscle, cardiac muscle, adipose, and liver tissue. These signaling molecules, which are collectively termed exerkines, form a heterogenous group of bioactive substances, mediating inter-organ crosstalk as well as structural and functional tissue adaption. Numerous scientific endeavors have focused on identifying and characterizing new biological mediators with such properties. Additionally, some investigations have focused on the molecular targets of exerkines and the cellular signaling cascades that trigger adaption processes. A detailed understanding of the tissue-specific downstream effects of exerkines is crucial to harness the health-related benefits mediated by exercise and improve targeted exercise programs in health and disease. Herein, we review the current in vivo evidence on exerkine-induced signal transduction across multiple target tissues and highlight the preventive and therapeutic value of exerkine signaling in various diseases. By emphasizing different aspects of exerkine research, we provide a comprehensive overview of (i) the molecular underpinnings of exerkine secretion, (ii) the receptor-dependent and receptor-independent signaling cascades mediating tissue adaption, and (iii) the clinical implications of these mechanisms in disease prevention and treatment.

The effect of exercise on flow-mediated dilation in people with type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials

Introduction

An increasing number of studies have investigated the effect of exercise on flow-mediated dilation (FMD) in people with type 2 diabetes mellitus (T2DM), while the findings were controversial. The primary aim of this systematic review and meta-analysis was to investigate the effect of exercise on FMD in T2DM patients, and the secondary aim was to investigate the optimal type, frequency, session duration, and weekly time of exercise for T2DM patients.

Methods

Searches were conducted in PubMed, Cochrane Library, Scopus, Web of Science, Embase and EBSCO databases. The Cochrane risk of bias tool (RoB2) in randomized trial and Physiotherapy Evidence Database (PEDro) scale were used to assess the methodological quality of the included studies.

Results

From the 3636 search records initially retrieved, 13 studies met the inclusion criteria. Our meta-analysis revealed that exercise had a significant effect on improving FMD in T2DM patients [WMD, 2.18 (95% CI, 1.78-2.58), p < 0.00001, I2 = 38%], with high-intensity interval training (HIIT) being the most effective intervention type [HIIT, 2.62 (1.42-3.82); p < 0.0001; aerobic exercise, 2.20 (1.29-3.11), p < 0.00001; resistance exercise, 1.91 (0.01-3.82), p = 0.05; multicomponent training, 1.49 (0.15-2.83), p = 0.03]. In addition, a higher frequency [> 3 times, 3.06 (1.94-4.19), p < 0.00001; ≤ 3 times, 2.02 (1.59-2.45), p < 0.00001], a shorter session duration [< 60 min, 3.39 (2.07-4.71), p < 0.00001; ≥ 60 min, 1.86 (1.32-2.40), p < 0.00001], and a shorter weekly time [≤ 180 min, 2.40 (1.63-3.17), p < 0.00001; > 180 min, 2.11 (0.82-3.40), p = 0.001] were associated with larger improvements in FMD.

Conclusion

This meta-analysis provides clinicians with evidence to recommended that T2DM patients participate in exercise, especially HIIT, more than 3 times per week for less than 60 min, with a target of 180 min per week being reached by increasing the frequency of exercise.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42023466575.

Dietary Phytochemical Index in Relation to Metabolic Health Status, Serum Adropin, and Brain-Derived Neurotrophic Factor Levels in Adults

Background

Little is known about the relationship between dietary intake of phytochemicals with metabolic health status and underlying mechanisms.

Objectives

Little is known about the relationship between dietary intake of phytochemicals with metabolic health status and underlying mechanisms. We hypothesized that dietary phytochemical index (DPI) improves metabolic health status by ameliorating serum concentrations of brain-derived neurotrophic factor (BDNF) and adropin.

Methods

A cross-sectional study was performed in 527 adults (286 males and 241 females). The dietary intakes of participants were collected by a 168-item food frequency questionnaire, and DPI was estimated as a percentage of energy intake derived from phytochemical-rich foods. Anthropometric variables, blood pressure, glycemic and lipid profiles, and biochemical variables were assessed. The metabolically unhealthy (MU) phenotype was determined based on the definition presented by Wildman et al.

Results

The MU phenotype was identified in 51.4% of male and 32.0% of female participants. Participants in the third tertile of DPI had 59% lower odds of MU than those in the first tertile (OR: 0.41; 95% CI: 0.19, 0.87) after considering potential confounders. Stratified analysis by sex and body mass index indicated that DPI was inversely related to MU phenotype in females (OR: 0.28; 95% CI: 0.08, 0.97) and normal-weight individuals (OR: 0.11; 95% CI: 0.02, 0.62). DPI was also inversely associated with hyperglycemia, hypertriglyceridemia, and chronic inflammation. Nonsignificant reduced odds of low BDNF (OR: 0.87; 95% CI: 0.42, 1.84) and adropin (OR: 0.75; 95% CI: 0.31, 1.79) were observed in individuals in the top tertile of DPI compared with those in the bottom tertile.

Conclusions

This study showed that individuals with higher dietary intake of phytochemicals had lower odds of MU, particularly females and normal-weight individuals. No significant relationship was observed between serum BDNF and adropin with phytochemical intake.

Low circulating adropin concentrations predict increased risk of cognitive decline in community-dwelling older adults

The secreted peptide adropin is highly expressed in human brain tissues and correlates with RNA and proteomic risk indicators for dementia. Here we report that plasma adropin concentrations predict risk for cognitive decline in the Multidomain Alzheimer Preventive Trial (ClinicalTrials.gov Identifier, NCT00672685; mean age 75.8y, SD = 4.5 years, 60.2% female, n = 452). Cognitive ability was evaluated using a composite cognitive score (CCS) that assessed four domains: memory, language, executive function, and orientation. Relationships between plasma adropin concentrations and changes in CCS (∆CCS) were examined using Cox Proportional Hazards Regression, or by grouping into tertiles ranked low to high by adropin values and controlling for age, time between baseline and final visits, baseline CCS, and other risk factors (e.g., education, medication, APOE4 status). Risk of cognitive decline (defined as a ∆CCS of - 0.3 or more) decreased with increasing plasma adropin concentrations (hazard ratio = 0.873, 95% CI 0.780-0.977, P = 0.018). Between adropin tertiles, ∆CCS was significantly different (P = 0.01; estimated marginal mean ± SE for the 1st to 3rd tertile, - 0.317 ± 0.064; - 0.275 ± 0.063; - 0.042 ± 0.071; n = 133,146, and 130, respectively; P < 0.05 for 1st vs. 2nd and 3rd adropin tertiles). Normalized plasma Aß42/40 ratio and plasma neurofilament light chain, indicators of neurodegeneration, were significantly different between adropin tertile. These differences were consistent with reduced risk of cognitive decline with higher plasma adropin levels. Overall, these results suggest cognitive decline is reduced in community-dwelling older adults with higher circulating adropin levels. Further studies are needed to determine the underlying causes of the relationship and whether increasing adropin levels can delay cognitive decline.

Legumes and nuts intake in relation to metabolic health status, serum brain derived neurotrophic factor and adropin levels in adults

There is controversial evidence about the relationship between consumption of legumes and nuts with metabolic disturbances. The present study was undertaken to explore the association of legumes and nuts intake with metabolic health status among Iranian adults. This cross-sectional study was conducted on 527 adults (45.7% female, aged 20-65 years) chosen through a multistage cluster random-sampling approach. Dietary intakes of individuals were assessed using a validated food frequency questionnaire. Fasting blood samples were gathered to evaluate biochemical parameters. Metabolic health status of subjects was determined according to the criteria defined by Wildman. Data of covariates were collected using pre-tested procedures. The overall prevalence of metabolic unhealthy (MU) phenotype was 42.5%. After controlling all confounders, participants with highest intake of legumes and nuts had lower odds of MU status, compared with the lowest intake (OR 0.35; 95% CI 0.18-0.71). This association was stronger in normal-weight rather than overweight/obese adults and also in women rather than men. Higher consumption of legumes and nuts was additionally related to decreased odds of hyperglycemia, hypertriglyceridemia, and hypertension. A marginally inverse association was observed between legumes and nuts intake with low brain-derived neurotrophic factor (BDNF) levels, in fully-adjusted model (ORT3 vs. T1 0.50; 95% CI 0.25-1.01). Each tertile increase in legumes and nuts intake was marginally related to higher adropin levels ([Formula: see text] = 4.06; P = 0.07). In conclusion, this study demonstrated that higher intake of legumes and nuts is associated with lower chance of MU both in normal weight and overweight/obese adults. The association may be facilitated through serum BDNF and adropin.

The effect of 8 weeks of combined interval (resistance-interval training) and combined endurance (endurance-resistance training) on plasma levels of adropin and nitric oxide in males with high blood pressure

INTRODUCTION

Nitric oxide (NO) is a vasodilator that plays an important role in blood pressure control. The purpose of the present study was to compare the effect of 8 weeks of resistance-interval and endurance-resistance trainings on plasma levels of adropin and NO in males with hypertension.

METHOD

Forty-five patients with hypertension were recruited and divided into 3 groups of control (age = 51.1 ± 6.4 years, body mass = 80.4 ± 9.2 kg), resistance-interval training (age = 50.7 ± 5.5 years, body mass = 78.1 ± 11 kg), and endurance-resistance training (age = 52.8 ± 6.1 years, body mass = 79.6 ± 9.2 kg). The resistance training program was performed in 2 sets, 10 to 15 repetitions, with 50% intensity of one repetition maximum. Increasing endurance training was performed for 30-40 min at 60-70% of maximum heart rate (HRmax) on the bike. The high-intensity interval training program consisted of 4 intervals of 80 to 90% of HRmax and 3-min recovery periods of 60 to 70% of HRmax. Blood samples were collected 1 week before the start of the training program and 48 h after the last training session. Plasma levels of adropin and nitrite/nitrate were measured by ELISA before and after the exercise interventions.

RESULTS

Eight weeks of resistance-interval and endurance-resistance trainings increased plasma levels of adropin and NO and decreased blood pressure (P ≤ 0.05). Furthermore, plasma levels of adropin increased in both exercise groups, whereas NO levels increased only in the endurance-resistance training. Systolic blood pressure decreased in the resistance-interval training (P ≤ 0.05) while it remained unchanged in the endurance-resistance group.

CONCLUSION

Resistance-interval and endurance-resistance trainings are effective in decreasing blood pressure by increasing cardiorespiratory capacity and plasma levels of adropin and NO.

Adropin increases with swimming exercise and exerts a protective effect on the brain of aged rats

Adropin is a protein in the brain that decreases with age. Exercise has a protective effect on the endothelium by increasing the level of adropin in circulation. In this study, whether adropin, whose level in the brain decreases with age, may increase with swimming exercise, and exhibit a protective effect was investigated. Young and aged male Sprague Dawley rats were submitted to 1 h of swimming exercise every day for 8 weeks. Motor activity parameters were recorded at the end of the exercise or waiting periods before the animals were euthanized. Increased motor functions were observed in only the young rats that exercised regularly. Adropin levels in the plasma, and the adropin and VEGFR2 immunoreactivities and p-Akt (Ser473) levels in the frontal cortex were significantly increased in the aged rats that exercised regularly. It was also observed that the BAX/Bcl2 ratio and ROS-RNS levels decreased, while the TAC levels increased in the aged rats that exercised regularly. The results of the study indicated that low-moderate chronic swimming exercise had protective effects by increasing the level of adropin in the frontal cortex tissues of the aged rats. Adropin is thought to achieve this effect by increasing the VEGFR2 expression level and causing Akt (Ser473) phosphorylation. These results indicated that an exercise-mediated increase in endogenous adropin may be effective in preventing the destructive effects of aging on the brain.

Young Women Are Protected Against Vascular Insulin Resistance Induced by Adoption of an Obesogenic Lifestyle

Vascular insulin resistance is a feature of obesity and type 2 diabetes that contributes to the genesis of vascular disease and glycemic dysregulation. Data from preclinical models indicate that vascular insulin resistance is an early event in the disease course, preceding the development of insulin resistance in metabolically active tissues. Whether this is translatable to humans requires further investigation. To this end, we examined if vascular insulin resistance develops when young healthy individuals (n = 18 men, n = 18 women) transition to an obesogenic lifestyle that would ultimately cause whole-body insulin resistance. Specifically, we hypothesized that short-term (10 days) exposure to reduced ambulatory activity (from >10 000 to <5000 steps/day) and increased consumption of sugar-sweetened beverages (6 cans/day) would be sufficient to prompt vascular insulin resistance. Furthermore, given that incidence of insulin resistance and cardiovascular disease is lower in premenopausal women than in men, we postulated that young females would be protected against vascular insulin resistance. Consistent with this hypothesis, we report that after reduced ambulation and increased ingestion of carbonated beverages high in sugar, young healthy men, but not women, exhibited a blunted leg blood flow response to insulin and suppressed skeletal muscle microvascular perfusion. These findings were associated with a decrease in plasma adropin and nitrite concentrations. This is the first evidence in humans that vascular insulin resistance can be provoked by short-term adverse lifestyle changes. It is also the first documentation of a sexual dimorphism in the development of vascular insulin resistance in association with changes in adropin levels.

Time-dependent relationships between exercise training-induced changes in nitric oxide production and hormone regulation

Aerobic exercise training (AT) reduces aging-induced deterioration of arterial stiffness and is associated with arterial nitric oxide (NO) production via changes in apelin and adropin as NO-upregulating hormones, and asymmetric dimethylarginine (ADMA) as a NO-downregulating hormone. However, the time-dependent effects of AT on NO production via NO-regulating hormones remain unclear. This study aimed to determine whether AT-induced changes in the time course of NO production via NO-regulating hormones, participate in the AT-induced improvement in central arterial stiffening with advancing age. Methods: Thirty-three healthy Japanese middle-aged and older subjects (67 ± 1 years) were randomly divided into two groups: AT intervention and sedentary controls. Subjects in the training group completed 8-week of AT. Carotid-femoral pulse wave velocity as an index of central arterial stiffness and plasma nitrate/nitrite levels significantly changed from baseline at weeks 6 (P < 0.05) and 8 (P < 0.01). Interestingly, circulating apelin and adropin levels gradually increased during AT intervention and significantly increased from baseline at weeks 4, 6, and 8 (P < 0.01). Additionally, plasma ADMA levels significantly decreased at 8-week AT intervention (P < 0.01). These results suggest that AT-induced changes in the time course of NO production via NO-regulating hormones may participate in AT-induced improvements of central arterial stiffening with advancing age.

Improved blood pressure and flow-mediated dilation via increased plasma adropin and NOx induced by high-intensity interval training in patients with type 2 diabetes

NEW FINDINGS

What is the central question of this study? Exercise training increases adropin and NOx plasma levels in middle-aged and older healthy people. We hypothesized that high-intensity interval training may improve blood pressure and flow-mediated dilation through the effects of adropin and NOx in patients of this age with type 2 diabetes. What is the main finding and its importance? High-intensity interval training may be more effective than moderate-intensity continuous training in improving endothelial function, blood pressure and flow-mediated dilation through its effects on adropin and NOx in patients with type 2 diabetes.

ABSTRACT

Adropin is a newly identified bioactive protein that is important in energy hemostasis and vascular endothelial function. Lower levels of adropin in patients with type 2 diabetes are related to coronary atherosclerosis, characterized by impaired flow-mediated dilation (FMD). The purpose of the present study was to investigate FMD, and plasma levels of adropin and nitrite/nitrate (NOx), in patients with type 2 diabetes at baseline and follow-up after 12 weeks of high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT). Sixty-six persons with type 2 diabetes were divided into HIIT, MICT and control groups. The HIIT group intervention was 12 intervals (1.5 min) at 85% to 90% maximal heart rate (HR_max ) separated by 2 min at 55% to 60% HR_max in 3 session per week for 12 weeks. MICT training consisted of 42 min of cycling at 70% HR_max . Before and after the intervention, FMD was recorded with high-resolution Doppler ultrasound. Plasma levels of adropin and NOx were measured by enzyme-linked immunosorbent assay. After training FMD was significantly higher in the MICT and HIIT groups compared to the control group (P<0.05). Plasma levels of adropin and NOx were higher in both exercise groups, but the increase was greater in the HIIT group (P<0.01). Peak oxygen consumption was increased after exercise training in both groups compared to the control group (P<0.01). Percent FMD showed a positive correlation with plasma levels of adropin and NOx (both P<0.01), and a negative correlation with DBP (r = -0.530, P = 0.035) and SBP (r = -0.606, P = 0.013) in the HIIT group. The results indicate that HIIT improved FMD whilst increasing adropin, NOx and peak oxygen consumption. Increased plasma levels of adropin may contribute, in part, to blood pressure reduction by increasing nitric oxide production. This article is protected by copyright. All rights reserved.

The association between serum adropin and carotid atherosclerosis in patients with type 2 diabetes mellitus: a cross‑sectional study

BACKGROUND

Adropin, a newly‑identified energy homeostasis protein, has been implicated in the maintenance of metabolic homeostasis and insulin sensitivity. This study attempts to measure the association between serum adropin and carotid atherosclerosis in patients with type 2 diabetes mellitus (T2DM).

METHODS

This cross‑sectional study was performed in 503 hospitalized patients with T2DM.Serum adropin level was measured by a sandwich enzyme-linked immunosorbent assay. The carotid atherosclerosis was assessed by color Doppler sonography. The association between adropin and carotid atherosclerotic plaque was tested by logistic regression model. The effect of adropin on carotid intimal-medial thickness (CIMT) was estimated using linear regression model.

RESULTS

Overall, 280 (55.7%) patients had carotid atherosclerotic plaque. The risk of carotid atherosclerotic plaque decreased with the increment of serum adropin level (adjusted odds ratio [aOR], 0.90; 95%CI: 0.81-0.99) in patients with T2DM. Serum adropin (Standardized β = - 0.006, p = 0.028) was also independently protective factor for CIMT in patients with T2DM.

CONCLUSION

In patients with T2DM, high serum adropin level was correlated with a decreased risk of carotid atherosclerosis in T2DM patients. Low circulating level of adropin may promote carotid atherosclerosis.

Effects of multicomponent exercise training intervention on hemodynamic and physical function in older residents of long-term care facilities: A multicenter randomized clinical controlled trial

OBJECTIVES

To assess hemodynamic and physical function responses during a two-month multicomponent group exercise program (MCEP) in residents of long-term care facilities.

METHODS

40 older long-term care residents were randomly allocated equally to an intervention (IG; n = 20; 80 ± 7 years) and control group (CG; n = 20; 79 ± 7 years); they all submitted to hemodynamic (blood pressure and heart rate) and functional assessments before and after the MCEP. The IG performed a twice-weekly, two-months multicomponent exercise program composed of functional mobility, balance, muscle strength, and flexibility exercises; while the CG did not perform any exercise intervention.

RESULTS

There was a statistically significant decrease in systolic blood pressure (7.25 ± 14.64 mmHg; t = 2.2; effect size = 0.34; p < 0.05) following a two-month MCEP as compared with baseline. In all functional measurements (balance, mobility) were significantly improved after the MCEP (p < 0.05).

DISCUSSION

These data indicate that a two-month MCEP can improve systolic blood pressure and functionality in older residents of long-term care facilities.

Low-to-Moderate-Intensity Resistance Exercise Effectively Improves Arterial Stiffness in Adults: Evidence From Systematic Review, Meta-Analysis, and Meta-Regression Analysis

Background/Purpose: Resistance exercise (RE) is known to improve cardiovascular health, but the role of RE variables on arterial stiffness is inconclusive. In this systematic review and meta-analysis, we investigated the influence of RE and its intensities on arterial stiffness measured as pulse wave velocity (PWV) in young and middle-aged adults. Methods: Web of Science, PubMed/MEDLINE, Scopus, EMBASE, Cochrane Library, ScienceDirect, CINAHL, Wiley Online Library, and Google Scholar were searched for relevant studies. RE trials that reported PWV data, and compared with respective controls were included. The Cochrane Collaboration tool was used to assess the risk of bias. Results: Data were synthesized from a total of 20 studies, involving 981 participants from control (n = 462) and exercise (n = 519) trials. The test for overall effect (pooled outcome) showed RE intervention had no effect on arterial stiffness (SMD = -0.09; 95% CI: -0.32, 0.13; P = 0.42), but risk of heterogeneity (I 2) was 64%. Meta-regression results revealed a significant correlation (P = 0.042) between RE intensity and PWV changes. Consequently, the trials were subgrouped into high-intensity and low-to-moderate-intensity to identify the effective RE intensity. Subgroup analysis showed that low-to-moderate-intensity significantly decreased PWV (SMD = -0.34; 95% CI: -0.51, -0.17; P < 0.0001), while high-intensity had no effect (SMD = 0.24; 95% CI: -0.18, 0.67; P = 0.26). When trials separated into young and middle-aged, low-to-moderate-intensity notably decreased PWV in young (SMD = -0.41; 95% CI: -0.77, -0.04; P = 0.03) and middle-aged adults (SMD = -0.32; 95% CI: -0.51, -0.14; P = 0.0007), whereas high-intensity had no effect in both age groups. Conclusions: Our findings demonstrated that RE intensity is the key variable in improving arterial stiffness. Low-to-moderate-intensity can prescribe as an effective non-pharmacological strategy to treat cardiovascular complications in young and middle-aged adults.

Role of Adropin in Cardiometabolic Disorders: From Pathophysiological Mechanisms to Therapeutic Target

Although a large amount of data supports the crucial role of endothelial dysfunction (ED) in cardiovascular diseases (CVDs), there is a large bench-to-bedside chasm between basic and clinical research of ED, limiting the implementation of these findings in everyday clinical settings. Hence, it is important to further investigate the pathophysiological mechanisms underlying ED and find modalities that will alleviate its clinical implementation. Adropin, a highly conserved peptide hormone secreted primarily by the liver, recently emerged as an important regulatory component of the vascular endothelium. Specifically, the vasoprotective role of adropin is achieved mainly by affecting endothelial NO synthesis. Thus, in this review, we aimed to summarize the current knowledge regarding the role of adropin in physiological processes and address the protective role of adropin in endothelium with consequent implications to CV pathologies. We focused on data regarding the role of adropin in the clinical setting, with concurrent implications to future clinical use of adropin. Studies suggest that plasma levels of adropin correlate with indices of ED in various pathologies and enhanced disease progression, implying that adropin may serve as a useful biomarker of ED in the upcoming future. On the other hand, despite notable results with respect to therapeutic potential of adropin in preliminary experiments, further well-designed studies are warranted in order to establish if adropin might be beneficial in this setting.

Effect of High-intensity Interval Training on Endothelial Function in Type 2 Diabetic Females

Background: Flow-mediated dilation (FMD) is a noninvasive approach to examine endothelial function. Objectives: The purpose of this study was to investigate the effect of 12 weeks of high-intensity interval training (HIIT) on FMD and circulating levels of adropin and nitric oxide (NO) in females with type 2 diabetes. Methods: Thirty females with type 2 diabetes were randomly assigned into two equal groups of HIIT and control. The exercise program consisted of three sessions a week for 12 weeks. Each training session included 4 × 4-minute running intervals at 85 - 95% of maximal heart rate (HRmax) with 3-minute active recoveries at 50 - 60% of HRmax. Circulating levels of adropin, NO, glucose, HbA1c, insulin, HOMA-IR, as well as lipid profile, and body composition parameters were measured before and after the intervention. Results: A significant increase of FMD% was observed after the intervention in the HIIT group (P = 0.001). In addition, the circulation levels of adropin and NO enhanced as a result of HIIT (P = 0.012 and P < 0.001, respectively). There were also significant positive effects on the levels of lipid profile (except for HDL), FBS, and HbA1c; as well as on the insulin resistance and the body composition variables. There were no significant changes in the control group except an increase in the total cholesterol levels (P < 0.01). Conclusions: The results showed that 12 weeks of the HIIT program could improve the endothelial function, glucose-related indices, lipid profile, and body composition variables in females with type 2 diabetes.

Lower Lean Mass Is Associated with Greater Arterial Stiffness in Patients with Lower Extremity Artery Disease

Background: Arterial stiffness is independently associated with lower extremity artery disease (LEAD). Although obesity is already known as an independent cardiovascular risk factor, it was found that, paradoxically, in patients diagnosed with cardiovascular disease, an increase in body mass index (BMI) was associated with a decrease in mortality. However, the underlying mechanism of this paradoxical association remain uncertain. In this study, we firstly hypothesize that arterial stiffness correlates with body mass; secondly, the underlying mechanism of the association for patients with LEAD is individual body composition, in particular, lean mass. Methods: The present study was performed as a single-center, prospective, observational analysis. A total of 412 patients with current or previously diagnosed LEAD (Rutherford Classification 2–4) were included, the cfPWV and AIx were measured as indices of arterial stiffness, and a body composition assessment was performed. Results: In male patients, there was a significantly negative correlation between the AIx and lean mass coefficient (p = 0.004, 95% CI: −0.28 (−0.48–0.09)). Conclusion: For patients with peripheral arterial disease, our data show that lower lean mass in male patients is associated with increased arterial stiffness as measured by the AIx. Therefore, progressive resistance training may be beneficial for the reduction in arterial stiffness in PAD patients in secondary prevention.

Changes in plasma C1q, apelin and adropin concentrations in older adults after descending and ascending stair walking intervention

This study compared changes in plasma complement component 1q (C1q), apelin and adropin concentrations in older obese women after descending (DSW) and ascending stair walking (ASW) training (n = 15/group) performed twice a week for 12 weeks, with gradual increases in exercise time from 5 to 60 min. Fasting blood samples were collected 3 days before the first and 4 days after the last training session. The improvements in the maximal voluntary isometric contraction (MVIC) strength of the knee extensors, functional physical fitness [e.g., 30-s chair stand (CS) performance], resting systolic blood pressure (SBP), insulin sensitivity [e.g., oral glucose tolerance test (OGTT)] and blood lipid profiles [e.g., total cholesterol (TC)] were greater (p < 0.05) in the DSW than ASW group. Plasma C1q decreased (− 51 ± 30%), and apelin (23 ± 15%) and adropin (127 ± 106%) increased (p ≤ .0.05) only after DSW. Significant (p ≤  0.01) partial correlations were found between the pre- to post-DSW changes in C1q, apelin or adropin and changes in outcome measures [e.g., C1q and MVIC (r = − 0.837), apelin and SBP (r = − 0.854), and andropin and OGTT (r = − 0.729)]. These results showed that greater decreases in plasma C1q and greater increases in apelin and adropin concentrations were associated with greater improvements in outcome measures after DSW than after ASW.

Exercise in the cold causes greater irisin release but may not be enough for adropin

When irisin and adropin were discovered, it was popularly hoped that they would become therapies for metabolic disorders that threaten global health. However, contradictory results have been reported in the subsequent period. Irisin, induced by exercise or cold exposure, is believed to be a myokine that causes the browning of adipose tissue thus increasing energy expenditure. Adropin is thought to be beneficial for health by regulating blood flow, capillary density, and playing an active role in glucose and insulin homeostasis. However, there were no experimental studies investigating the simultaneous effect of exercise and cold exposure in humans. The purpose of this study was to investigate irisin and adropin responses in young healthy individuals performing aerobic exercise in different environmental temperatures. Twenty-seven young, healthy individuals participated in this study. Participants performed 40 min of aerobic running exercise in environmental temperatures of 0°C, 12°C, and 24°C. Venous blood samples were taken pre- and post-exercise. Irisin and adropin levels were analyzed using an enzyme-linked immunosorbent assay. The principal findings showed that while serum irisin concentrations significantly increased after aerobic exercise was performed at an environmental temperature of 0°C, there was no significant difference between pre- and post-exercise recordings for physical activity performed at 12°C and 24°C. Adropin concentrations, however, remained unchanged between pre- and post-exercise at 0°C, 12°C, and 24°C. Interestingly, the exercise at 0°C caused an increase in adropin (12.5%), but this amount was not enough to be a statistically significant result. The findings of this study suggest that aerobic exercise in a cold environment causes greater irisin release. However, the combined effect of exercise and cold exposure may not be enough to statistically increase adropin level.

Aerobic Exercise Restores Aging-Associated Reductions in Arterial Adropin Levels and Improves Adropin-Induced Nitric Oxide-Dependent Vasorelaxation

Background Adropin is a peptide hormone that promotes nitric oxide (NO) production via activation of endothelial NO synthase (eNOS) in endothelial cells. Its circulating levels are reduced with aging and increased with aerobic exercise training (AT). Using a mouse model, we hypothesized that AT restores aging-associated reductions in arterial and circulating adropin and improves adropin-induced NO-dependent vasorelaxation. Further, we hypothesized these findings would be consistent with data obtained in elderly humans. Methods and Results In the animal study, 50-week-old SAMP1 male mice that underwent 12 weeks of voluntary wheel running, or kept sedentary, were studied. A separate cohort of 25-week-old SAMP1 male mice were used as a mature adult sedentary group. In the human study, 14 healthy elderly subjects completed an 8-week AT program consisting of 45 minutes of cycling 3 days/week. In mice, we show that advanced age is associated with a decline in arterial and circulating levels of adropin along with deterioration of endothelial function, arterial NO production, and adropin-induced vasodilation. All these defects were restored by AT. Moreover, AT-induced increases in arterial adropin were correlated with increases in arterial eNOS phosphorylation and NO production. Consistently with these findings in mice, AT in elderly subjects enhanced circulating adropin levels and these effects were correlated with increases in circulating nitrite/nitrate (NOx) and endothelial function. Conclusions Changes in arterial adropin that occur with age or AT relate to alterations in endothelial function and NO production, supporting the notion that adropin should be considered a therapeutic target for vascular aging. Registration URL: https://www.umin.ac.jp; Unique identifier: UMIN000035520.

Effects of eight weeks exercise training on serum levels of adropin in male volleyball players

OBJECTIVES

To evaluate the effects of an eight week exercise program on the lipid profile in serum, serum levels of adropin, systolic blood pressure (SBP), and diastolic blood pressure (DBP) in male volleyball players.

METHODS

Sixteen healthy male volleyball players participated in this study. Subjects performed eight weeks of aerobic and resistance training, and body mass index (BMI), body fat ratio, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), adropin, SBP, and DBP values were measured at the start (untrained) and end (trained) of training. Non-HDL-C was calculated by subtracting HDL-C from TC.

RESULTS

Body fat percentage and BMI values decreased significantly after eight weeks of exercise training. There was a statistically significant decrease in the post-test values of LDL-C, TG, non-HDL-C, and DBP compared to pre-test measurements. There was a significant increase in the trained levels of adropin and HDL-C compared to untrained levels. Pearson's correlation analyses revealed a negative and significant relationship between changes in DBP and adropin levels before and after exercise.

CONCLUSIONS

Eight weeks of exercise training decreased LDL-C, TG, non-HDL-C, and DBP and an increased serum levels of adropin in male volleyball players.

Relationship between plasma asymmetric dimethylarginine and nitric oxide levels affects aerobic exercise training-induced reduction of arterial stiffness in middle-aged and older adults

Purpose

Aerobic exercise training (AT) reverses aging-induced deterioration of arterial stiffness via increased arterial nitric oxide (NO) production. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, was decreased by AT. However, whether AT-induced changes in ADMA levels are related to changes in nitrite/nitrate (NOx) levels remains unclear. Accordingly, we aimed to clarify whether the relationship between plasma ADMA and NOx levels affected the AT-induced reduction of arterial stiffness in middle-aged and older adults.

Methods

Thirty-one healthy middle-aged and older male and female subjects (66.4 ± 1.3 years) were randomly divided into two groups: exercise intervention and sedentary controls. Subjects in the training group completed an 8-week AT (60%-70% peak oxygen uptake [V̇O2peak] for 45 min, 3 days/week).

Results

AT significantly increased V̇O2peak (P < 0.05) and decreased carotid β-stiffness (P < 0.01). Moreover, plasma ADMA levels were significantly decreased while plasma NOx levels and NOx/ADMA ratio were significantly increased by AT (P < 0.01). Additionally, no sex differences in AT-induced changes of circulating ADMA and NOx levels, NOx/ADMA ratio, and carotid β-stiffness were observed. Furthermore, the AT-induced increase in circulating ADMA levels was negatively correlated with an increase in circulating NOx levels (r = -0.414, P < 0.05), and the AT-induced increase in NOx/ADMA ratio was negatively correlated with a decrease in carotid β-stiffness (r = -0.514, P < 0.01).

Conclusion

These results suggest that the increase in circulating NOx with reduction of ADMA elicited by AT is associated with a decrease in arterial stiffness regardless of sex in middle-aged and older adults.

The paradox of the role of resistin in early-onset obesity hypertension: A comparative study among four Chinese adult subgroups

Objective: To explore the role of resistin in the onset and development of obesity-related hypertension.Methods: Resistin serum levels were tested by ELISA in 153 adult subjects among four characteristic Chinese adult physical examination groups. Waist circumference (WC), body mass index (BMI), systolic blood pressure (SB), diastolic blood pressure (DB), and other clinical laboratory data were collected. Following, correlations between research index and differences between groups were analyzed using SPSS.Results: Serum resistin levels statistically significantly negatively correlated with SB, DB and BMI, but statistically significantly positively correlated with serum creatinine (SCR) and serum albumin (ALB), even after adjustment for age and/or gender. The serum level of resistin in the normal healthy subject group (NH) was higher than in other groups.Conclusions: Resistin's role in the onset of obesity-related hypertension may be more important than what has been previously assumed. More pathway substances in the early onset of obesity-related hypertension should be tested.Abbreviations: WC, waist circumference; GGT, Gamma-glutamyltransferase; ALB, Albumin; ALT, Alanine aminotransferase; LDL, Low density lipoprotein cholesterol; TG, Triglyceride; HDLC, High density lipoprotein cholesterol; FA Fructosamine; SCR, serum creatinine; IB, Indirect bilirubin; ALP, Alkaline phosphatase; CB, Conjugated bilirubin; UREA, Urea; Ua, Uric acid; FBG, fasting blood glucose; TC, Total cholesterol; TB, Total bilirubin; TP, Total protein; TC/HDLC, TC/HDLC ratio; SB, systolic blood pressure; DB, diastolic blood pressure.

Exercise suppresses NLRP3 inflammasome activation in mice with diet-induced NASH: a plausible role of adropin

NLRP3 inflammasome activation, which can be triggered by reactive oxygen species (ROS), contributes to nonalcoholic steatohepatitis (NASH) progression. Exercise is an effective therapeutic strategy for NASH. However, whether exercise prevents NLRP3 activation in NASH has not been investigated. Here, we investigated the effect of exercise on NLRP3 inflammasome in mice with high-fat diet (HFD)-induced or methionine and choine-deficient (MCD) diet-induced NASH and explored whether adropin, a metabolic peptide hormone shown to inhibit inflammation, mediates an exercise-induced benefit against NLRP3 inflammasome activation. Exercise alleviated diet-induced hepatic steatosis, inflammation, and fibrosis. Importantly, exercise significantly reduced the expression of NLRP3 inflammasome components, decreased Caspase-1 enzymatic activity, normalized IL-1β production, and suppressed ROS overproduction in HFD-fed and MCD diet-fed mice. The exercise-elicited NLRP3 inflammasome inhibition was accompanied by increased adropin levels. Moreover, serum adropin levels were negatively correlated with serum IL-1β levels. We further explored the effect of adropin on the NLRP3 inflammasome in palmitic acid (PA)-treated hepatocytes and Kupffer cells. Although adropin treatment did not significantly decrease the levels of all inflammasome components, it reduced the active Caspase-1 level, decreased Caspase-1 activity and downregulated IL-1β expression in hepatocytes and Kupffer cells (KCs) treated with PA. Moreover, ROS levels in PA-stimulated hepatocytes and Kupffer cells were reduced upon adropin treatment. In summary, we demonstrated that the inhibitory effect of exercise on NLRP3 inflammasome activation was associated with adropin induction, resulting in NASH improvement.

Hepatokines as a Molecular Transducer of Exercise

Exercise has health benefits and prevents a range of chronic diseases caused by physiological and biological changes in the whole body. Generally, the metabolic regulation of skeletal muscle through exercise is known to have a protective effect on the pathogenesis of metabolic syndrome, non-alcoholic fatty liver disease (NAFLD), type 2 diabetes (T2D), and cardiovascular disease (CVD). Besides this, the importance of the liver as an endocrine organ is a hot research topic. Hepatocytes also secrete many hepatokines in response to nutritional conditions and/or physical activity. In particular, certain hepatokines play a major role in the regulation of whole-body metabolic homeostasis. In this review, we summarize the recent research findings on the exercise-mediated regulation of hepatokines, including fibroblast growth factor 21, fetuin-A, angiopoietin-like protein 4, and follistatin. These hepatokines serve as molecular transducers of the metabolic benefits of physical activity in chronic metabolic diseases, including NAFLD, T2D, and CVDs, in various tissues.

Effect of Exercise on Cardiovascular Function Following Spinal Cord Injury: A REVIEW

Spinal cord injury (SCI) is associated with a reduced level of physical activity, deterioration of patient body composition, metabolic profile, quality of life, and psychological functioning. As a result, risk of cardiovascular disease (CVD) increases and CVD-related death occurs at an earlier age than in individuals without SCI. Regular participation in exercise has been shown to exert beneficial effects also in patients with SCI. In this review, we analyze and discuss the effects of regular exercise training in SCI on cardiovascular function, autonomic function of the cardiovascular system, arterial stiffness, metabolism, inflammation, and gene expression.

Adropin: a hepatokine modulator of vascular function and cardiac fuel metabolism

Adropin is a nutritionally regulated peptide hormone, secreted primarily by the liver, which modulates metabolic homeostasis in a number of tissues. Growing evidence suggests that adropin is an important regulatory component in a number of cardiovascular pathologies, and may be central to the control of cardiac fuel metabolism and vascular function. In this mini-review, we examine the known facets of adropin biology, discuss open questions in the field, and speculate on the therapeutic potential of targeting adropin-related signaling pathways in cardiovascular diseases.

Swim therapy-induced tissue specific metabolic responses in male rats

Swim therapy in the form of moderate physical activity has general health benefits. Regular exercise prevents the progression of chronic diseases affecting the different bodily systems. The metabolic alterations associated with following such lifestyle remain not fully understood. The aim of the present study was to elucidate the metabolic changes following prolonged swim therapy. Twenty-four Sprague Dawley rats were divided into sedentary and exercise groups. Our results revealed that regular exercise significantly increased the serum levels of growth hormone (GH), glucagon and corticosterone. A reduction in the circulating levels of irisin and insulin hormones, and glucose were noticed alongside with an upregulation in the mRNA expression levels of FNDC5, PGC-1α, GLUT-4 and preptin receptors with downregulation in the expression of Enho gene in the heart of exercised rats. Liver of the exercised rats showed elevation in the transcriptional levels of Enho gene, PPARα, and preptin with reduction in the transcriptional levels of preptin receptors. Exercise induced an increase in the pancreatic mRNA of Enho gene, preptin and preptin receptors, and a reduction in FNDC5, PPARα and PGC-1α. An elevation in the gastrocnemius muscle PGC-1α mRNA expression and a decline in the soleus muscle Enho mRNA were found. Exercise diminishes the activities of SOD, CAT and GPx in the gastrocnemius muscle, liver and pancreas. Myogenin expression increased in all examined skeletal muscles. This study takes into account the complex crosstalk between different signaling pathways in skeletal muscles, heart, liver and pancreas as well as the metabolic alterations in response to regular exercise.

Aerobic exercise training-induced irisin secretion is associated with the reduction of arterial stiffness via nitric oxide production in adults with obesity

This study aimed to clarify whether muscle-derived irisin secretion induced by aerobic exercise training is involved in reduction of arterial stiffness via arterial nitric oxide (NO) productivity in obesity. In animal study, 16 Otsuka Long-Evans Tokushima Fatty (OLETF) rats with obesity were randomly divided into 2 groups: sedentary control (OLETF-CON) and 8-week aerobic treadmill training (OLETF-EX) groups. In human study, 15 subjects with obesity completed 8-week aerobic exercise training for 45 min at 60%-70% peak oxygen uptake intensity for 3 days/week. As a result of animal study, carotid-femoral pulse wave velocity (cfPWV) was decreased, and arterial phosphorylation levels of AMP-activated protein kinase (AMPK), protein kinase B (Akt), and endothelial NO synthase (eNOS), circulating levels of nitrite/nitrate (NOx) and irisin, and muscle messenger RNA expression of fibronectin type III domain containing 5 (Fndc5) were increased in the OLETF-EX group compared with OLETF-CON group. In a human study, regular aerobic exercise reduced cfPWV and elevated circulating levels of NOx and irisin. Furthermore, change in circulating irisin levels by regular exercise was positively correlated with circulating NOx levels and was negatively correlated with cfPWV. Thus, aerobic exercise training-induced increase in irisin secretion may be related to reduction of arterial stiffness achieved by NO production via activated arterial AMPK-Akt-eNOS signaling pathway in obesity. Novelty Aerobic exercise training promoted irisin secretion with upregulation of muscle Fndc5 gene expression in rats with obesity. Irisin affected the activation of arterial AMPK-Akt-eNOS signaling by aerobic exercise training. Increased serum irisin level by aerobic exercise training was associated with reduction of arterial stiffness in obese adults.

Adropin reduces blood glucose levels in mice by limiting hepatic glucose production

Adropin is a liver- and brain-secreted peptide hormone with striking effects on fuel metabolism regulation in a number of tissues. Previous studies demonstrated that adropin secretion is decreased in obese mice subjected to a long-term high-fat diet (HFD), and that whole-body loss of adropin expression resulted in systemic insulin resistance. Treatment of obese mice with adropin improves glucose tolerance, which has been linked to increased glucose oxidation and inhibition of fatty acid utilization in isolated skeletal muscle homogenates. In this study, we used in vivo physiological measurements to determine how treatment of obese mice with adropin affects whole-body glucose metabolism. Treatment with adropin reduced fasting blood glucose and, as shown previously, increased glucose tolerance in HFD mice during standard glucose tolerance tests. Under hyperinsulinemic-euglycemic clamp conditions, adropin treatment led to a nonsignificant increase in whole-body insulin sensitivity, and a significant reduction in whole-body glucose uptake. Finally, we show that adropin treatment suppressed hepatic glucose production and improved hepatic insulin sensitivity. This correlated with reduced expression of fatty acid import proteins and gluconeogenic regulatory enzymes in the liver, suggesting that adropin treatment may impact the pathways that drive vital aspects of hepatic glucose metabolism.

Obesity-Induced Hypertension: Heavy on the Accelerator

See Article Fan et al.

Adropin as A Fat-Burning Hormone with Multiple Functions-Review of a Decade of Research

Adropin is a unique hormone encoded by the energy homeostasis-associated (Enho) gene. Adropin is produced in the liver and brain, and also in peripheral tissues such as in the heart and gastrointestinal tract. Furthermore, adropin is present in the circulatory system. A decade after its discovery, there is evidence that adropin may contribute to body weight regulation, glucose and lipid homeostasis, and cardiovascular system functions. In this review, we summarize and discuss the physiological, metabolic, and pathophysiological factors regulating Enho as well as adropin. Furthermore, we review the literature addressing the role of adropin in adiposity and type 2 diabetes. Finally, we elaborate on the role of adropin in the context of the cardiovascular system, liver diseases, and cancer.

Increased serum salusin-α by aerobic exercise training correlates with improvements in arterial stiffness in middle-aged and older adults

Aging causes arterial stiffening which can be mitigated by increased physical activity. Although low circulating levels of salusin-α are associated with cardiovascular disease, whether salusin-α decreases with aging and whether the reduced arterial stiffening occurring with exercise training is associated with increased serum salusin-α is unknown. Herein we assessed carotid-femoral pulse wave velocity (cfPWV), systolic (SBP) and diastolic (DBP) blood pressures in a cross-sectional study that compared young (20-39-year-old, n=45) versus middle-aged and older (40-80-year-old, n=60) subjects. We also performed an interventional study in which 36 young and 40 middle-aged and older subjects underwent eight weeks of aerobic exercise training. In the cross-sectional study, serum salusin-α levels were lesser in middle-aged and older subjects compared to young individuals and negatively correlated with age, SBP, DBP, or cfPWV. In the interventional study, exercise training increased serum salusin-α in middle-aged and older subjects. Notably, negative correlations were noted between the exercise training-induced changes in serum salusin-α and cfPWV, SBP and DBP. Results indicate that advanced age associates with low circulating salusin-α, the levels of which can be augmented by exercise training. Importantly, increased serum salusin-α with exercise correlates with improvements in arterial stiffness and a reduction in blood pressure.

Combined aerobic and low-intensity resistance exercise training increases basal nitric oxide production and decreases arterial stiffness in healthy older adults

Meta-analyses have concluded that combined aerobic and high-intensity or moderate-intensity resistance exercise training has no effects on arterial stiffness. However, a recent study demonstrated that combined aerobic training and resistance training using rubber bands increases basal nitric oxide (NO) production and decreases arterial stiffness with marked reduction of body weight in obese adolescent girls. To investigate whether combined aerobic and low-intensity resistance training increases basal NO production and decreases arterial stiffness without body weight reduction in older adults, 27 healthy older individuals participated in a 6-week program as a part of the training group (mean body mass index, 21 kg/m²; walking and resistance training using one’s body weight) or the control group (22 kg/m², asked not to modify their lifestyle). The exercise intervention increased aerobic capacity, muscle strength, and plasma concentrations of nitrite/nitrate (end products of NO) and decreased pulse wave velocity (an index of arterial stiffness) without changes in body weight. In the control group, there were no differences in these measures before and after the study period. These results suggest that combined aerobic and low-intensity resistance exercise training increases basal NO production and decreases arterial stiffness in healthy older adults.

Effects of Tai Chi on Cerebral Hemodynamics and Health-Related Outcomes in Older Community Adults at Risk of Ischemic Stroke: A Randomized Controlled Trial

This study investigated the effects of Tai Chi compared with no exercise control on the cerebral hemodynamic parameters and other health-related factors in community older adults at risk of ischemic stroke. A total of 170 eligible participants were randomly allocated to Tai Chi or control group. The cerebral hemodynamic parameters and physical fitness risk factors of cardiovascular disease were measured at baseline, 12 weeks, and 24 weeks. After the 12-week intervention, Tai Chi significantly improved the minimum of blood flow velocity (BFVmin); BFVmean; pulsatility index and resistance index of the right anterior cerebral artery; and BFVmax, BFVmin, and BFVmeanparameters of the right middle cerebral artery. Tai Chi training also decreased triglyceride, fasting blood glucose, and homocysteine levels, and improved balance ability. Therefore, the supervised 12-week Tai Chi exercise had potential beneficial effects on cerebral hemodynamics, plasma risk factors, and balance ability in older community adults at risk of ischemic stroke.

Nitric Oxide and Decreases in Resistance Exercise Blood Pressure With Aerobic Exercise Training in Older Individuals

An exaggerated blood pressure response to resistance exercise is a marker of masked hypertension and a risk factor for future essential hypertension. Habitual aerobic exercise decreases systolic blood pressure (SBP) during resistance exercise in older individuals, but the underlying mechanisms have not been explored. This study tested the hypothesis that nitric oxide (NO) mediates a reduction of resistance exercise SBP with aerobic training in older individuals. Normotensive older adults participated in a 6-week program as a part of the aerobic training group (n = 23, exercised for an average of 4.4 d/wk and 59 min/d) or the control group (n = 26, asked not to modify their lifestyle during the experimental period). The aerobic exercise intervention increased plasma concentrations of nitrite/nitrate (NOx, end products of NO) and decreased SBP during a one-hand arm curl exercise at 20% and 40% of one-repetition maximum and brachial-ankle pulse wave velocity (an index of arterial stiffness). In the control group, there were no differences in these measures before and after the experimental period. Changes in plasma NOx concentrations during the study period were correlated with changes in resistance exercise SBP. Stepwise regression revealed that changes in plasma NOx concentrations during the experimental period are a significant factor of changes in resistance exercise SBP, independent of age, sex, and changes in serum lipid profile, maximal oxygen uptake, resting SBP, and other variables. These results suggest that NO is associated with decreases in resistance exercise SBP with aerobic training in older individuals and help us better understand why habitual aerobic exercise prevents cardiovascular disease.

Vasodilatory function in human skeletal muscle feed arteries with advancing age: the role of adropin

KEY POINTS

The present study aimed to determine the impact of ageing on endogenous adropin levels in human skeletal muscle feed arteries (SMFAs) and the role of adropin in age-related vascular dysfunction. Adropin protein expression falls progressively with advancing age in the human peripheral vasculature. Endothelial-dependent vasodilatation, typically attenuated with age, was strongly correlated with SMFA adropin protein levels. Adropin incubation restored age-related endothelial-dependent vasodilatory dysfunction and increased the phosphorylated endothelial nitric oxide synthase (eNOS)/eNOS ratio in an age-dependent manner in the SMFAs. The role of nitric oxide bioavailability was additionally indicated by NOS blockade ablating both the positive vascular effects of adropin incubation and the relationship between endothelial function and adropin protein expression. Additional evidence of a mechanistic link between declining adropin and age-related endothelial dysfunction was documented by a progressively increasing magnitude of effect of adropin-induced eNOS-mediated vasodilatation with ageing. Adropin appears to be a novel therapeutic target for facilitating the restoration of endothelial function with ageing.

ABSTRACT

The present study aimed to determine the impact of advancing age on endogenous adropin levels in human skeletal muscle feed arteries (SMFAs) and the role of adropin in age-related vascular dysfunction. Adropin protein expression and vasodilatory capacity was assesed in SMFAs from Young (27 ± 2 years, n = 10), Middle Aged (54 ± 2 years, n = 10) and Old (75 ± 2 years, n = 16) subjects. Endothelial-dependent vasodilatation, with and without adropin incubation, was assessed in response to flow-induced shear stress and ACh. Both SMFA adropin protein expression and endothelial-dependent vasodilatory function exhibited a progressive, age-related, reduction (Flow: Y: 65 ± 3%; Middle Aged: 36 ± 3%; Old: 15 ± 2%; ACh: Young: 63 ± 2%, Middle Aged: 34 ± 3%; Old: 23 ± 3%, P < 0.05). There was a strong positive correlation between SMFA adropin protein expression and both flow (r = 0.81, P < 0.05) and ACh (r = 0.78, P < 0.05). Adropin incubation in the Middle Aged and Old SMFAs restored the vasodilatory response to flow (Middle Aged + Adropin: 59 ± 3%; Old + Adropin: 47 ± 3%, P < 0.05) and ACh (Middle Aged + Adropin: 59 ± 3%; Old + Adropin: 49 ± 2%, P < 0.05). A mechanistic link between adropin and nitric oxide (NO) biovavailabilty was supported by (i) increased phosphorylated endothelial NO synthase (eNOS)/eNOS protein expression with adropin incubation only in the Middle Aged and Old SMFAs; (ii) eNOS blockade ablating both the positive vascular effects of adropin incubation and the relationship between endothelial function and adropin protein expression and (iii) a progressive increase in the magnitude of effect of adropin-induced eNOS-mediated vasodilatation with advancing age. Adropin could be a novel therapeutic target for facilitating the restoration of endothelial function via increased NO bioavailability, with advancing age.

Benefits of exercise training on cardiovascular dysfunction: molecular and integrative

Exercise training has been shown to ameliorate a wide variety of cardiovascular disorders. The mechanisms by which long-term benefits of exercise training are mediated remains incomplete, despite intense research in this area. Exactly how the act of chronic exercise improves function in every tissue is unknown, but many of the cellular, molecular, and genetic mechanisms are becoming progressively clearer. This "Perspectives" article reviews the contributions of 15 articles published in the American Journal of Physiology-Heart and Circulatory Physiology in response to a Call for Papers in this area. Here, we summarize the contributions of these studies at the cardiac, vascular, immune, and molecular levels. We discuss the translational benefit of these studies and conclude that the beneficial effects of exercise training in cardiovascular disease is due to a large interplay of cellular and molecular mediators in the heart and peripheral vasculature as well as changes in neural elements that regulate blood pressure and blood flow. Readers are encouraged to evaluate and learn from this collection of novel studies.

Adropin regulates pyruvate dehydrogenase in cardiac cells via a novel GPCR-MAPK-PDK4 signaling pathway

Mitochondria supply ~90% of the ATP required for contractile function in cardiac cells. While adult cardiomyocytes preferentially utilize fatty acids as a fuel source for oxidative phosphorylation, cardiac mitochondria can switch to other substrates when required. This change is driven in part by a combination of extracellular and intracellular signal transduction pathways that alter mitochondrial gene expression and enzymatic activity. The mechanisms by which extracellular metabolic information is conveyed to cardiac mitochondria are not currently well defined. Recent work has shown that adropin – a liver-secreted peptide hormone – can induce changes in mitochondrial fuel substrate utilization in skeletal muscle, leading to increased glucose use. In this study, we examined whether adropin could regulate mitochondrial glucose utilization pathways in cardiac cells. We show that stimulation of cultured cardiac cells with adropin leads to decreased expression of the pyruvate dehydrogenase (PDH) negative regulator PDK4, which reduces inhibitory PDH phosphorylation. The downregulation of PDK4 expression by adropin is lost when GPR19 – a putative adropin receptor – is genetically depleted in H9c2 cells. Loss of GRP19 expression alone increased PDK4 expression, leading to a reduction in mitochondrial respiration. Finally, we show that adropin-mediated GPR19 signaling relies on the p44/42 MAPK pathway, and that pharmacological disruption of this pathway blocks the effects of adropin on PDK4 in cardiac cells. These findings suggest that adropin may be a key regulator of fuel substrate utilization in the heart, and implicates an orphan G-protein coupled receptor in a novel signaling pathway controlling mitochondrial fuel metabolism.

Effects of exercise intensity and cardiorespiratory fitness on the acute response of arterial stiffness to exercise in older adults

PURPOSE

Increased arterial stiffness is observed with ageing and in individuals with low cardiorespiratory fitness ([Formula: see text]O_2peak), and associated with cardiovascular risk. Following an exercise bout, transient arterial stiffness reductions offer short-term benefit, but may depend on exercise intensity. This study assessed the effects of exercise intensity on post-exercise arterial stiffness in older adults with varying fitness levels.

METHODS

Fifty-one older adults (72 ± 5 years) were stratified into fitness tertiles ([Formula: see text]O_2peak: low-, 22.3 ± 3.1; mid-, 27.5 ± 2.4 and high-fit 36.3 ± 6.5 mL kg^-1 min^-1). In a randomised order, participants underwent control (no-exercise), moderate-intensity continuous exercise (40% of peak power output; PPO), and higher-intensity interval exercise (70% of PPO) protocols. Pulse wave velocity (PWV), augmentation index (AIx75) and reflection magnitude (RM) were assessed at rest and during 90 min of recovery following each protocol.

RESULTS

After control, delta PWV increased over time (P < 0.001) and delta RM was unchanged. After higher-intensity interval exercise, delta PWV (P < 0.001) and delta RM (P < 0.001) were lower to control in all fitness groups. After moderate-intensity continuous exercise, delta PWV was not different from control in low-fit adults (P = 0.057), but was lower in the mid- and higher-fit older adults. Post-exercise AIx75 was higher to control in all fitness groups (P = 0.001).

CONCLUSIONS

In older adults, PWV increases during seated rest and this response is attenuated after higher-intensity interval exercise, regardless of fitness level. This attenuation was also observed after moderate-intensity continuous exercise in adults with higher, but not lower fitness levels. Submaximal exercise reveals differences in the arterial stiffness responses between older adults with higher and lower cardiorespiratory fitness.

Multicomponent Exercise Improves Physical Functioning but Not Cognition and Hemodynamic Parameters in Elderly Osteoarthritis Patients Regardless of Hypertension

The present study aimed to investigate the impact of a 6-month multicomponent exercise program (MCEP) on physical function, cognition, and hemodynamic parameters of elderly normotensive (NTS) and hypertensive (HTS) osteoarthritis patients. A total of 99 elderly osteoarthritis patients (44 NTS and 55 HTS) were recruited and submitted to functional, cognitive, and hemodynamic evaluations before and after six months of a MCEP. The program of exercise was performed twice a week at moderate intensity. The physical exercises aggregated functional and walking exercises. Results indicate that 6 months of MCEP were able to improve one-leg stand and mobility (walking speeds) of osteoarthritis patients regardless of hypertension. On the other hand, cognitive and hemodynamic parameters were not altered after the MCEP. The findings of the present study demonstrate that 6 months of MCEP were able to improve the physical functioning (i.e., usual and maximal walking speed and balance) of osteoarthritis patients regardless of hypertensive condition.

Therapeutic Approaches to Nonalcoholic Fatty Liver Disease: Exercise Intervention and Related Mechanisms

Exercise training ameliorates nonalcoholic fatty liver disease (NAFLD) as well as obesity and metabolic syndrome. Although it is difficult to eliminate the effects of body weight reduction and increased energy expenditure-some pleiotropic effects of exercise training-a number of studies involving either aerobic exercise training or resistance training programs showed ameliorations in NAFLD that are independent of the improvements in obesity and insulin resistance. In vivo studies have identified effects of exercise training on the liver, which may help to explain the "direct" or "independent" effect of exercise training on NAFLD. Exercise training increases peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) expression, improves mitochondrial function and leads to reduced hepatic steatosis, inflammation, fibrosis, and tumor genesis. Crosstalk between the liver and adipose tissue, skeletal muscle and the microbiome is also a possible mechanism for the effect of exercise training on NAFLD. Although numerous studies have reported benefits of exercise training on NAFLD, the optimal duration and intensity of exercise for the prevention or treatment of NAFLD have not been established. Maintaining adherence of patients with NAFLD to exercise training regimes is another issue to be resolved. The use of comprehensive analytical approaches to identify biomarkers such as hepatokines that specifically reflect the effect of exercise training on liver functions might help to monitor the effect of exercise on NAFLD, and thereby improve adherence of these patients to exercise training. Exercise training is a robust approach for alleviating the pathogenesis of NAFLD, although further clinical and experimental studies are required.