Vasopressin V1a receptor polymorphism and interval walking training effects in middle-aged and older people

Internet of Things (IoT) System and Field Sensors for Exercise Intensity Measurements

Although exercise training according to individual peak aerobic capacity ( V ˙ o_2peak ) has been recommended at all ages, sensors available in the field are limited. The most popular sensors in the field are pedometers, but they cannot be used to monitor exercise intensity. Instead, although heart rate (HR) monitors are broadly available in the field to estimate exercise intensity, HR responses to exercise vary by individual according to physical fitness and environmental conditions, which hinders the precise measurement of energy expenditure. These issues make it difficult for exercise physiologists to collaborate with geneticists, nutritionists, and clinicians using the internet of things (IoT). To conquer these problems, we have developed a device that is equipped with a triaxial accelerometer and a barometer to measure energy expenditure during interval walking training (IWT) in the field with inclines. IWT is a training regimen to repeat fast and slow walking for 3 min each, equivalent to greater than 70% and approximately 40% of individual V ˙ o_2peak , respectively. Additionally, we developed an IoT system that enables users to receive instructions from trainers according to their walking records even if they live far away. Since the system is available at low cost with minimum personnel, we can investigate any factors affecting the adherence to and effects of IWT in a large population for a long period. This system was also used to verify any effects of nutritional supplements during IWT and to examine the value of applying IWT to clinical medicine. © 2020 American Physiological Society. Compr Physiol 10:1207-1240, 2020.

Oxytocin and Vasopressin Systems in Obesity and Metabolic Health: Mechanisms and Perspectives

PURPOSE OF REVIEW

The neurohypophysial endocrine system is identified here as a potential target for therapeutic interventions toward improving obesity-related metabolic dysfunction, given its coinciding pleiotropic effects on psychological, neurological and metabolic systems that are disrupted in obesity.

RECENT FINDINGS

Copeptin, the C-terminal portion of the precursor of arginine-vasopressin, is positively associated with body mass index and risk of type 2 diabetes. Plasma oxytocin is decreased in obesity and several other conditions of abnormal glucose homeostasis. Recent data also show non-classical tissues, such as myocytes, hepatocytes and β-cells, exhibit responses to oxytocin and vasopressin receptor binding that may contribute to alterations in metabolic function. The modulation of anorexigenic and orexigenic pathways appears to be the dominant mechanism underlying the effects of oxytocin and vasopressin on body weight regulation; however, there are apparent limitations associated with their use in direct pharmacological applications. A clearer picture of their wider physiological effects is needed before either system can be considered for therapeutic use.

Copeptin relates to a fatty liver and measures of obesity in a South African population with mixed ethnicities

PURPOSE

Elevated copeptin, a vasopressin marker, is linked to metabolic disease, and obese rats with low-vasopressin concentration had a decreased risk of liver steatosis. We here investigated the association between copeptin and nonalcoholic fatty liver disease (NAFLD) and possible differences in copeptin concentration between ethnicities.

METHODS

In this cross-sectional study of 361 South Africans (n = 172 African black, 189 = Caucasian) with a mean age of 45 years and 45% men, plasma copeptin was measured and associated with NAFLD according to a validated fatty liver index accounting for measures of BMI, waist, triglycerides, and gamma-glutamyltransferase.

RESULTS

There was no significant difference in copeptin concentrations between ethnicities after age and gender adjustment (p = 0.24). Increasing copeptin tertile levels were significantly associated with obesity, overweight, and abdominal obesity, respectively, after multivariate adjustment for age, gender, ethnicity, and high HOMA-IR (p = 0.02 for all). Individuals in the second and third copeptin tertile had an increased odds (95% CI) of NAFLD of 1.77 (1.04-3.02) and 2.97 (1.74-5.06), respectively, compared to the bottom tertile (p < 0.001). The association between increasing copeptin tertile and NAFLD remained significant after adjustment for age, gender, ethnicity, high HOMA-IR, self-reported current alcohol intake, and statin treatment (p = 0.01).

CONCLUSIONS

Elevated plasma copeptin is independently associated with NAFLD in a population with mixed ethnicities, pointing at the pharmacologically modifiable vasopressin system as a new mechanism behind NAFLD.

A Systematically Assembled Signature of Genes to be Deep-Sequenced for Their Associations with the Blood Pressure Response to Exercise

: Background: Exercise is one of the best nonpharmacologic therapies to treat hypertension. The blood pressure (BP) response to exercise is heritable. Yet, the genetic basis for the antihypertensive effects of exercise remains elusive. Methods: To assemble a prioritized gene signature, we performed a systematic review with a series of Boolean searches in PubMed (including Medline) from earliest coverage. The inclusion criteria were human genes in major BP regulatory pathways reported to be associated with: (1) the BP response to exercise; (2) hypertension in genome-wide association studies (GWAS); (3) the BP response to pharmacotherapy; (4a) physical activity and/or obesity in GWAS; and (4b) BP, physical activity, and/or obesity in non-GWAS. Included GWAS reports disclosed the statistically significant thresholds used for multiple testing. Results: The search yielded 1422 reports. Of these, 57 trials qualified from which we extracted 11 genes under criteria 1, 18 genes under criteria 2, 28 genes under criteria 3, 27 genes under criteria 4a, and 29 genes under criteria 4b. We also included 41 genes identified from our previous work. Conclusions: Deep-sequencing the exons of this systematically assembled signature of genes represents a cost and time efficient approach to investigate the genomic basis for the antihypertensive effects of exercise.

Water intake keeps type 2 diabetes away? Focus on copeptin

INTRODUCTION

In both diabetic subjects and animal models high levels of vasopressin (AVP) have beendetected. The relationship between AVP and glucose metabolism is mediated through several direct andindirect effects and most of them are still unknown.

METHODS

We have reviewed 100 manuscripts retrieved from Cochrane Library, Embase and Pubmeddatabases in order to highlight a possible relationship between copeptin and type 2 diabetes and to provideinsights on the molecular mechanism that could explain this association.

RESULTS AND CONCLUSIONS

AVP potentiates CRH action at pituitary level resulting in an increased ACTH secretion and in turn in an increased cortisol secretion that escapes the negative feedback loop. Further, AVP regulates insulin and glucagon secretion through V1b receptor and promotes hepatic glycogenolysis and gluconeogenesis through V1a receptor. In addition to worsen glucose metabolism, AVP has been reported to have a role in the pathogenesis of diabetic complications such as cardiovascular diseases, kidney and ocular complications. Due to the very low concentration of AVP in the blood, the small size and poor stability, the assay of AVP is very difficult to perform. Thus, copeptin, the stable C-terminal portion of the prepro-vasopressin peptide has been identified as an easier assay to be measured and that mirrors AVP activity. Although there are promising evidence that copeptin could be involved in the pathogenesis of type 2 diabetes, further studies need to demonstrate the importance of copeptin as clinical marker to predict glucose metabolism derangements.

Interval Walking Training Can Increase Physical Fitness in Middle-Aged and Older People

No long-term exercise training regimen with high adherence and effectiveness for middle-aged and older individuals is currently broadly available in the field. To address this problem, we developed an exercise training system comprising interval walking training and an information technology network that requires only minimal staff support. We hypothesized that our training system could increase physical fitness in older people.

Associations Between Vocal Symptoms and Genetic Variants in the Oxytocin Receptor and Arginine Vasopressin 1A Receptor Gene

PURPOSE

Oxytocin and arginine vasopressin are associated with different aspects of the stress response. As stress is regarded as a risk factor for vocal symptoms, we wanted to explore the association between the oxytocin receptor gene (OXTR) and arginine vasopressin 1A receptor gene (AVPR1A) single-nucleotide polymorphisms (SNPs) and vocal symptoms. We also wanted to explore whether such effects might be mediated by cortisol because oxytocin and vasopressin are associated with cortisol levels.

METHOD

A population-based sample (N = 657) of Finnish twins (born 1961-1989) completed a web questionnaire on the occurrence of vocal symptoms. A total of 170 participants submitted saliva samples for hormone analysis. A total of 20 OXTR and AVPR1A SNPs were analyzed.

RESULTS

Three OXTR polymorphisms (rs2270465, rs2268493, rs7632287) and 2 AVPR1A polymorphisms (rs1587097, rs1042615) showed nominal effects (p < .05) on vocal symptoms, of which 1 (rs1587097) remained significant after correcting for multiple testing (p = .003). We found potential mediation of the effect of the OXTR rs2268493 polymorphism on vocal symptoms through levels of cortisol.

CONCLUSIONS

The associations between variants of OXTR and AVPR1A and vocal symptoms indicate that oxytocin and vasopressin might influence vocal symptoms. The effect of oxytocin seems to be partly mediated through cortisol actions.

Serum levels of copeptin are associated with type 2 diabetes and diabetic complications in Chinese population

PURPOSE

The aim of this study was to investigate copeptin levels in serum, and assess their associations with type 2 diabetes (T2DM) and diabetic complications.

METHODS

In this post hoc analysis, serum levels of copeptin were tested in 306 patients with T2DM. Clinical information including diabetic retinopathy (DR) and diabetic nephropathy (DN) were collected. The relation of serum copeptin with DR and DN were investigated with the use of logistic regression models according to equal quartiles of the distributions of serum copeptin.

RESULTS

We found that serum copeptin levels were significantly higher in diabetes as compared to normal controls [9.4(IQR, 7.4-12.5) pmol/L vs. 4.1(IQR, 2.5-6.2) pmol/L; P<0.0001]. In multivariate analysis, there was an increased risk of T2DM associated with copeptin levels (OR 1.312, 95% CI: 1.204-1.403; P<0.0001) after adjusting for possible confounders. After adjustment for possible confounders, serum copeptin levels were positively associated with the DR (odds ratio [OR], 1.117; 95% confidence interval [CI], 1.072-1.241; P<0.001) and DN (OR, 1.259; 95% CI, 1.198-1.323; P<0.001). Compared with the first quartile of serum copeptin levels, the ORs for DR and DN were as follows: second quartile, 1.19 (95% CI, 0.94-1.51, P=0.12) and 1.37 (95% CI, 0.78-2.37, P=0.28); third quartile, 1.61 (95% CI, 1.18-2.43, P=0.005) and 2.12 (95% CI, 1.32-3.27, P=0.003); fourth quartile, 2.83 (95% CI, 2.04-4.93; P<0.001) and 3.48 (95% CI, 1.77-7.03; P<0.001), respectively.

CONCLUSIONS

Using a post-hoc analysis our data show that elevated serum levels of copeptin are associated with type 2 diabetes and diabetic complications in Chinese population, suggesting a potential role of the AVP system (copeptin) in the pathophysiology of diabetes.

Implementation of interval walking training in patients with type 2 diabetes in Denmark: rationale, design, and baseline characteristics

Promoting physical activity is a first-line choice of treatment for patients with type 2 diabetes (T2D). However, there is a need for more effective tools and technologies to facilitate structured lifestyle interventions and to ensure a better compliance, sustainability, and health benefits of exercise training in patients with T2D. The InterWalk initiative and its innovative application (app) for smartphones described in this study were developed by the Danish Centre for Strategic Research in T2D aiming at implementing, testing, and validating interval walking in patients with T2D in Denmark. The interval walking training approach consists of repetitive 3-minute cycles of slow and fast walking with simultaneous intensity guiding, based on the exercise capacity of the user. The individual intensity during slow and fast walking is determined by a short initial self-conducted and audio-guided fitness test, which combined with automated audio instructions strives to motivate the individual to adjust the intensity to the predetermined individualized walking intensities. The InterWalk app data are collected prospectively from all users and will be linked to the unique Danish nationwide databases and administrative registries, allowing extensive epidemiological studies of exercise in patients with T2D, such as the level of adherence to InterWalk training and long-term effectiveness surveys of important health outcomes, including cardiovascular morbidity and mortality. Currently, the InterWalk app has been downloaded by >30,000 persons, and the achieved epidemiological data quality is encouraging. Of the 9,466 persons providing personal information, 80% of the men and 62% women were overweight or obese (body mass index ≥25). The InterWalk project represents a contemporary technology-driven public health approach to monitor real-life exercise adherence and to propagate improved health through exercise intervention in T2D and in the general population.

Genetic vasopressin 1b receptor variance in overweight and diabetes mellitus

OBJECTIVE

Recently, imbalance in the vasopressin (AVP) system, measured as elevated levels of copeptin (the C-terminal part of the AVP pro-hormone) in plasma, was linked to the development of abdominal obesity and diabetes mellitus (DM). Here, we aim to investigate if the genetic variation of the human AVP receptor 1b gene (AVPR1B) is associated with measures of obesity and DM.

DESIGN

Malmö Diet and Cancer study (MDC) is a population-based prospective cohort examined 1991-1996.

METHODS

Four tag single nucleotide polymorphisms (SNPs: rs35810727, rs28373064, rs35439639, rs35608965) of AVPR1B were genotyped in the cardiovascular cohort (n=6103) of MDC (MDC-CC) and associated with measures of obesity and DM. Significant SNPs were replicated in another 24 344 MDC individuals (MDC replication cohort).

RESULTS

In MDC-CC, the major allele of rs35810727 was associated with elevated BMI (β-coefficient ± s.e.m.; 0.30 ± 0.14, P=0.03) and waist (0.78 ± 0.36, P=0.03) after age and gender adjustment. The association with BMI was replicated in the MDC replication cohort (0.21 ± 0.07, P=0.003), whereas that with waist was not significant. In MDC-CC there was no association between the major allele of rs35810727 and DM, but in the complete MDC cohort (n=30 447) the major allele of rs35810727 was associated with DM (OR (95% CI); 1.10 (1.00-1.20), P=0.04).

CONCLUSIONS

Genetic variance of AVPR1B contributes to overweight. Furthermore, our data indicate a link between AVPR1B variance and DM development. Our data point at a relationship between the disturbance of the pharmacologically modifiable AVP system and the body weight regulation.

Target intensity and interval walking training in water to enhance physical fitness in middle-aged and older women: a randomised controlled study

PURPOSE

To determine the target intensity for fast walking during interval walking training (IWT) in water for middle-aged and older people to enhance physical fitness.

METHODS

Thirty-one women [59 ± 5 (SD) years old] were randomly divided into two groups: IWT on land (LG, N = 15) and in water (WG, N = 16). All subjects were instructed to perform ≥ 6 sets of fast and slow walking for 3 min each in a day, ≥ 4 days week(-1), for 8 weeks, at an intensity 35% higher than the oxygen consumption rate at the gas exchange threshold (VO2GET), with a subjective feeling of 16-18 points of the Borg scale during fast walking in each condition. Before and after IWT, we measured VO2GET, peak aerobic capacity (VO2peak) by graded walking and cycling tests on land and isometric knee extension (F EXT) and flexion (F FLX) forces.

RESULTS

Before IWT, the VO2GET for walking in water was 14% higher and the heart rate (HR) at a given VO2 was ~10 beats min(-1) lower (P=0.001) than on land. During IWT, subjects in both groups performed IWT for ~4 days week(-1)(P > 0.9) with a 14% higher fast walking intensity in WG than in LG (P < 0.05). After IWT, the VO2peak and VO2GET for cycling, F EXT and F FLX increased more in WG than in LG (all, P < 0.05).

CONCLUSION

Walking in water elevated VO2GET and decreased HR at a given exercise intensity in middle-aged and older women, which enabled them to perform exercise at a higher metabolic rate than on land due to improved subjective feelings, which, for these subjects, resulted in greater gains in physical fitness.

The blood pressure response to acute and chronic aerobic exercise: A meta-analysis of candidate gene association studies

OBJECTIVES

To meta-analyze candidate gene association studies on the change in blood pressure beyond the immediate post-exercise phase after versus before aerobic exercise.

DESIGN

Meta-analysis.

METHODS

A systematic search was conducted. Studies retrieved included acute (short-term or postexercise hypotension) or chronic (long-term or training) aerobic exercise interventions; and blood pressure measured before and after aerobic exercise training, or before and after exercise or control under ambulatory conditions by genotype. Effect sizes were determined for genotype and adjusted for sample features.

RESULTS

Qualifying studies (k=17, n=3524) on average included middle-aged, overweight men (44.2%) and women (55.8%) with prehypertension (134.9±11.7/78.6±9.5mmHg). Training interventions (k=12) were performed at 60.4±12.9% of maximum oxygen consumption (VO2max) for 41.9±12.5minsession(-1), 3.6±1.2daysweek(-1) for 15.7±7.6week; and post-exercise hypotension interventions (k=5) were performed at 53.5±14.4% VO2max for 38.5±5.4minsession(-1). Sample characteristics explained 54.2-59.0% of the variability in the blood pressure change after versus before acute exercise or control under ambulatory conditions, and 57.4-67.1% of the variability in the blood pressure change after versus before training (p<0.001). Only angiotensinogen M235T (rs699) associated with the change in diastolic blood pressure after versus before training (R(2)=0.1%, p=0.05), but this association did not remain statistically significant after adjustment for multiple comparisons.

CONCLUSIONS

Sample characteristics explained most of the variability in the change of BP beyond the immediate post-exercise phase after versus before acute and chronic aerobic exercise. Angiotensinogen M235T (rs699) was the only genetic variant that associated with the change in diastolic blood pressure after versus before training, accounting for <1% of the variance.

The factors affecting adherence to a long-term interval walking training program in middle-aged and older people

No long-term exercise training regimen with high adherence and effectiveness in middle-aged and older people is broadly available in the field. We assessed the adherence to, and effects of, our long-term training program comprising an interval walking training (IWT) and an information technology network system and the factors affecting adherence. Middle-aged and older men and women [n = 696, aged 65 ± 7(SD) yr] underwent IWT. The subjects were instructed to repeat five or more sets of fast and slow walking for 3 min each at ≥70 and 40% peak aerobic capacity for walking (V̇O2peak), respectively, per day ≥4 days/wk for 22 mo. Adherence was assessed as training days accomplished relative to the target of 4 days/wk over 22 mo. The effects on the V̇O2peak and lifestyle-related disease score were evaluated every 6 mo. The independent factors affecting adherence were assessed by multiple-regression analysis after adjustment for baseline physical characteristics and other possible covariates, including vasopressin V1a receptor polymorphisms. The adherence over 22 mo averaged 70% and was highly correlated with a 13% reduction in the lifestyle-related disease score (R(2) = 0.94, P = 0.006) and with a 12% increase in V̇O2peak (R(2) = 0.94, P = 0.006). The major determinant of higher adherence was lower baseline body mass index (BMI) (P < 0.0001) and male sex (P < 0.0001). For men, in addition to BMI, nonsmokers (P = 0.031) and V1a receptor polymorphisms (P = 0.033) were independent determinants of higher adherence. Thus the long-term IWT program is an effective regimen. Moreover, baseline BMI and sex for all subjects, and smoking and V1a receptor polymorphisms for men, were associated with adherence.

Genes, physical fitness and ageing

Persons aged 80 years and older are the fastest growing segment of the population. As more individuals live longer, we should try to understand the mechanisms involved in healthy ageing and preserving functional independence in later life. In elderly people, functional independence is directly dependent on physical fitness, and ageing is inevitably associated with the declining functions of systems and organs (heart, lungs, blood vessels, skeletal muscles) that determine physical fitness. Thus, age-related diminished physical fitness contributes to the development of sarcopenia, frailty or disability, all of which severely deteriorate independent living and thus quality of life. Ageing is a complex process involving many variables that interact with one another, including - besides lifestyle factors or chronic diseases - genetics. Thus, several studies have examined the contribution of genetic endowment to a decline in physical fitness and subsequent loss of independence in later life. In this review, we compile information, including data from heritability, candidate-gene association, linkage and genome-wide association studies, on genetic factors that could influence physical fitness in the elderly.

Copeptin, a marker of vasopressin, in abdominal obesity, diabetes and microalbuminuria: the prospective Malmö Diet and Cancer Study cardiovascular cohort

BACKGROUND

High plasma copeptin (copeptin), the C-terminal fragment of arginine vasopressin pro-hormone, has been associated with the metabolic syndrome (MetS), diabetes mellitus (DM) development and nephropathy. Here we tested whether elevated copeptin level is associated with later development of the MetS, its individual components and microalbuminuria.

METHODS

We analysed copeptin at baseline (1991-1994) in the population-based Malmö Diet and Cancer Study cardiovasular cohort and re-examined 2064 subjects 15.8 years later (mean age 72.8 years, 59% women) with oral glucose tolerance test and measurement of MetS and its individual components.

RESULTS

After age and sex adjustment, increasing quartiles of copeptin at baseline (the lowest quartile as reference) were associated with MetS (P for trend=0.008), incident abdominal obesity (P for trend=0.002), DM (P for trend=0.001) and microalbuminuria (P for trend=0.002). After additional adjustment for all the MetS components at baseline, increasing copeptin quartiles predicted incident abdominal obesity (odds ratios 1.55, 1.30 and 1.59; P for trend=0.04), DM (odds ratios 1.18, 1.32 and 1.46; P for trend=0.04) and microalbuminuria (odds ratios 1.05, 1.08 and 1.65; P for trend=0.02) but not MetS (P for trend=0.19) at the reexamination. Further, the relationship between copeptin and microalbuminuria was independent of baseline C-reactive protein, incident DM and incident hypertension.

CONCLUSION

Copeptin independently predicts DM and abdominal obesity but not the cluster of MetS. Apart from predicting DM and abdominal obesity, elevated copeptin signals increased risk of microalbuminuria. Interestingly, the association between copeptin and later microalbuminuria was independent of both prevalent and incident DM and hypertension. Our findings suggest a relationship between a dysregulated vasopressin system and cardiometabolic risk, which could have implications for risk assessment and novel preventive treatments.

Genetics of hypertension and cardiovascular disease and their interconnected pathways: lessons from large studies

Blood pressure (BP), hypertension (HT) and cardiovascular disease (CVD) are common complex phenotypes, which are affected by multiple genetic and environmental factors. This article describes recent genome-wide association studies (GWAS) that have reported causative variants for BP/HT and CVD/heart traits and analyzes the overlapping associated gene polymorphisms. It also examines potential replication of findings from the HyperGEN data on African Americans and whites. Several genes involved in BP/HT regulation also appear to be involved in CVD. A better picture is emerging, with overlapping hot-spot regions and with interconnected pathways between BP/HT and CVD. A systemic approach to full understanding of BP/HT and CVD development and their progression to disease may lead to the identification of gene targets and pathways for the development of novel therapeutic interventions.

Beyond epidemiology: field studies and the physiology laboratory as the whole world

There is no exercise training regimen broadly available in the field to increase physical fitness and prevent lifestyle-related diseases in middle-aged and older people. We have developed interval walking training (IWT) repeating five or more sets of 3 min fast walking at 70% peak aerobic capacity for walking (w ) per day with intervening 3 min slow walking at 40% w , for 4 days week(1), for 5 months. Moreover, to determine w in individuals and also to measure their energy expenditure even while incline walking, we have developed a portable calorimeter. Further, to instruct subjects on IWT even if they live remotely from the trainers, we have developed e-Health Promotion System. This transfers individual energy expenditure during IWT stored on the meter to a central server through the internet; it sends back the achievement to individuals along with advice generated automatically by the sever according to a database on 4000 subjects. Where we found that 5 months of IWT increased physical fitness and improved the indices of lifestyle-related diseases by 10-20% on average. Since our system is run at low cost with fewer staff for more subjects, it enables us to develop exercise prescriptions appropriate for individuals.