Running from Disease: Molecular Mechanisms Associating Dopamine and Leptin Signaling in the Brain with Physical Inactivity, Obesity, and Type 2 Diabetes

Nucleus accumbens D1- and D2-expressing neurons control the balance between feeding and activity-mediated energy expenditure

Accumulating evidence points to dysregulations of the Nucleus Accumbens (NAc) in eating disorders (ED), however its precise contribution to ED symptomatic dimensions remains unclear. Using chemogenetic manipulations in male mice, we found that activity of dopamine D1 receptor-expressing neurons of the NAc core subregion facilitated effort for a food reward as well as voluntary exercise, but decreased food intake, while D2-expressing neurons have opposite effects. These effects are congruent with D2-neurons being more active than D1-neurons during feeding while it is the opposite during running. Chronic manipulations of each subpopulations had limited effects on energy balance. However, repeated activation of D1-neurons combined with inhibition of D2-neurons biased behavior toward activity-related energy expenditure, whilst the opposite manipulations favored energy intake. Strikingly, concomitant activation of D1-neurons and inhibition of D2-neurons precipitated weight loss in anorexia models. These results suggest that dysregulations of NAc dopaminoceptive neurons might be at the core of EDs.

High Intensity Interval Training can Ameliorate Hypothalamic Appetite Regulation in Male Rats with Type 2 Diabetes: The Role of Leptin

Disruption of leptin (LEP) signaling in the hypothalamus caused by type 2 diabetes (T2D) can impair appetite regulation. The aim of this study was to investigate whether the improvement in appetite regulation induced by high-intensity interval training (HIIT) in rats with T2D can be mediated by LEP signaling. In this study, 20 male Wister rats were randomly assigned to one of four groups: CO (non-type 2 diabetes control), T2D (type 2 diabetes), EX (non-type 2 diabetes exercise), and T2D + EX (type 2 diabetes + exercise).To induce T2D, a combination of a high-fat diet for 2 months and a single dose of streptozotocin (35 mg/kg) was administered. Rats in the EX and T2D + EX groups performed 4-10 intervals of treadmill running at 80-100% of their maximum velocity (Vmax). Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), serum levels of insulin (INS) and LEP (LEPS) as well as hypothalamic expression of LEP receptors (LEP-R), Janus kinase 2 (JAK-2), signal transducer and activator of transcription 3 (STAT-3), neuropeptide Y (NPY), agouti-related protein (AGRP), pro-opiomelanocortin cocaine (POMC), amphetamine-related transcript (CART), suppressor of cytokine signaling (SOCS3), forkhead box protein O1 (FOXO1) were assessed. ANOVA and Tukey post hoc tests were used to compare the results between the groups. The levels of LEPS and INS, as well as the levels of LEP-R, JAK-2, STAT-3, POMC, and CART in the hypothalamus were found to be higher in the T2D + EX group compared to the T2D group. On the other hand, the levels of HOMA-IR, NPY, AGRP, SOCS3, and FOXO1 were lower in the T2D + EX group compared to the T2D group (P < 0.0001). The findings of this study suggest that HIIT may improve appetite regulation in rats with T2D, and LEP signaling may play a crucial role in this improvement. Graphical abstract (leptin signaling in the hypothalamus), Leptin (LEP), Leptin receptor (LEP-R), Janus kinase 2 (JAK2), Signal transducer and activator of transcription 3 (STAT3), expressing Neuropeptide Y (NPY), Agouti-related protein (AGRP), anorexigenic neurons (expressing pro-opiomelanocortin cocaine (POMC), Amphetamine-related transcript (CART), suppressor of cytokine signaling (SOCS3), forkhead box protein O1 (FOXO1).

Prolactin in Polycystic Ovary Syndrome: Metabolic Effects and Therapeutic Prospects

Polycystic ovary syndrome (PCOS) is the most prevalent endocrine and metabolic disorder in premenopausal women, characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. Patients frequently present comorbidities, including obesity, insulin resistance, and impaired glucose and lipid metabolism. The diverse clinical presentation may mimic various endocrine disorders, making the diagnosis challenging in some clinical circumstances. Prolactin (PRL) is a recommended biomarker in the initial diagnostic workup to rule out hyperprolactinemia (HPRL). The traditional role of PRL is linked to lactation and the reproductive system. Recent research highlights PRL's emerging role in metabolic homeostasis. PRL influences metabolism directly by interacting with the pancreas, liver, hypothalamus, and adipose tissue. Its influence on an individual's metabolism is intricately tied to its serum concentration. While deficient and very high levels of PRL can negatively affect metabolism, intermediate-normal to moderately high levels may promote metabolic health. In women with PCOS, PRL levels may be altered. Research results on different aspects of the relationship between PCOS and the impact of various levels of PRL on metabolic homeostasis are limited and inconsistent. In this narrative literature review, we comprehensively examined data on serum PRL levels in PCOS patients. We investigated the correlation between a favorable metabolic profile and serum PRL levels in this population. Furthermore, we explored the concept of beneficial PRL effects on metabolism and discussed the potential therapeutic application of dopamine agonists in PCOS treatment. Lastly, we emphasized several promising avenues for future research in this field.

Leptin Signaling Could Mediate Hippocampal Decumulation of Beta-Amyloid and Tau Induced by High-Intensity Interval Training in Rats with Type 2 Diabetes

Leptin (LEP) can cross the blood-brain barrier and facilitate cross-talk between the adipose tissue and central nerve system (CNS). This study aimed to investigate the effect of 8-week high-intensity interval training (HIIT) on the LEP signaling in the hippocampus of rats with type 2 diabetes. 20 rats were randomly divided into four groups: (i) control (Con), (ii) type 2 diabetes (T2D), (iii) exercise (EX), and (iv) type 2 diabetes + exercise (T2D + EX). The rats in the T2D and T2D + EX were fed a high-fat diet for two months, then a single dose of STZ (35 mg/kg) was injected to induce diabetes. The EX and T2D + EX groups performed 4-10 intervals of treadmill running at 80-100% of Vmax. Serum and hippocampal levels of LEP as well as hippocampal levels of LEP receptors (LEP-R), Janus kinase 2 (JAK-2), signal transducer and activator of transcription 3 (STAT-3), activated protein kinase (AMP-K), proxy zoster receptor α (PGC-1α), beta-secretase 1 (BACE1), Beta-Amyloid (Aβ), Phosphoinositide 3-kinases (PI3K), protein kinase B (AKT), mammalian target of rapamycin (mTOR), Glycogen Synthase Kinase 3 Beta (GSK3β), and hyperphosphorylated tau proteins (TAU) were measured. One-way ONOVA and Tukey post-hoc tests were used to analyze the data. Serum and hippocampal levels of LEP as well as hippocampal levels of LEP-R, JAK-2, STAT-3, AMP-K, PGC1α, PI3K, AKT, and mTOR were increased while hippocampal levels of BACE1, GSK3B, TAU, and Aβ were decreased in T2D + EX compared with T2D group. Serum LEP and hippocampal levels of LEP, LEP-R, JAK-2, STAT-3, AMP-K, PGC1α, PI3K, AKT, and mTOR were decreased. Conversely hippocampal levels of BACE1, GSK3B, TAU, and Aβ were increased in T2D group compared with CON group. HIIT could improve LEP signaling in the hippocampus of rats with type 2 diabetes and decrease the accumulation of Tau and Aβ, which may reduce the risk of memory impairments.

The Genetic Basis of Childhood Obesity: A Systematic Review

Overweight and obesity in childhood and adolescence represents one of the most challenging public health problems of our century owing to its epidemic proportions and the associated significant morbidity, mortality, and increase in public health costs. The pathogenesis of polygenic obesity is multifactorial and is due to the interaction among genetic, epigenetic, and environmental factors. More than 1100 independent genetic loci associated with obesity traits have been currently identified, and there is great interest in the decoding of their biological functions and the gene-environment interaction. The present study aimed to systematically review the scientific evidence and to explore the relation of single-nucleotide polymorphisms (SNPs) and copy number variants (CNVs) with changes in body mass index (BMI) and other measures of body composition in children and adolescents with obesity, as well as their response to lifestyle interventions. Twenty-seven studies were included in the qualitative synthesis, which consisted of 7928 overweight/obese children and adolescents at different stages of pubertal development who underwent multidisciplinary management. The effect of polymorphisms in 92 different genes was assessed and revealed SNPs in 24 genetic loci significantly associated with BMI and/or body composition change, which contribute to the complex metabolic imbalance of obesity, including the regulation of appetite and energy balance, the homeostasis of glucose, lipid, and adipose tissue, as well as their interactions. The decoding of the genetic and molecular/cellular pathophysiology of obesity and the gene-environment interactions, alongside with the individual genotype, will enable us to design targeted and personalized preventive and management interventions for obesity early in life.

APOE ε4 and exercise interact in a sex-specific manner to modulate dementia risk factors

Introduction

Apolipoprotein E (APOE) ε4 is the strongest genetic risk factor for Alzheimer's disease and related dementias (ADRDs), affecting many different pathways that lead to cognitive decline. Exercise is one of the most widely proposed prevention and intervention strategies to mitigate risk and symptomology of ADRDs. Importantly, exercise and APOE ε4 affect similar processes in the body and brain. While both APOE ε4 and exercise have been studied extensively, their interactive effects are not well understood.

Methods

To address this, male and female APOE ε3/ε3, APOE ε3/ε4, and APOE ε4/ε4 mice ran voluntarily from wean (1 month) to midlife (12 months). Longitudinal and cross-sectional phenotyping were performed on the periphery and the brain, assessing markers of risk for dementia such as weight, body composition, circulating cholesterol composition, murine daily activities, energy expenditure, and cortical and hippocampal transcriptional profiling.

Results

Data revealed chronic running decreased age-dependent weight gain, lean and fat mass, and serum low-density lipoprotein concentration dependent on APOE genotype. Additionally, murine daily activities and energy expenditure were significantly influenced by an interaction between APOE genotype and running in both sexes. Transcriptional profiling of the cortex and hippocampus predicted that APOE genotype and running interact to affect numerous biological processes including vascular integrity, synaptic/neuronal health, cell motility, and mitochondrial metabolism, in a sex-specific manner.

Discussion

These data in humanized mouse models provide compelling evidence that APOE genotype should be considered for population-based strategies that incorporate exercise to prevent ADRDs and other APOE-relevant diseases.

Dispersion of daily physical activity behaviors in school-age children: A novel approach to measure patterns of physical activity

PURPOSE

The objectives of this paper are (1) to examine patterns of physical activity (PA) and sedentary behavior; (2) to describe development of a method to quantify movement dispersion; and (3) to determine the relationship between variables of movement (i.e., volume, intensity, and dispersion), volume of sedentary behavior, and estimated cardiorespiratory capacity in school-aged children.

DESIGN AND METHODS

A secondary analysis of an existing data set with raw accelerometer data identified PA patterns of movement dispersion in school-aged children. Bar graphs visually depicted each participant's daily vector magnitude counts. The research team developed a dispersion variable-movement dispersion-and formula to provide a new quantification of daily PA patterns. Total movement dispersion represents both intensity and distribution of movement, whereas pure movement dispersion refers to the distribution of movement during the wear time, independent of intensity. Kendall's tau examined the relationship between several variables: body mass index percentile, average minutes of sedentary behavior, average minutes of light PA, average minutes of moderate-vigorous PA (MVPA), derived VO2 max, total movement dispersion, and pure movement dispersion.

RESULTS

Three participants' activity graphs were presented as examples: (1) active, (2) inactive, and (3) mixed. The more active participant had the highest values for pure and total movement dispersion. The inactive participant had much lower pure and total movement dispersion values compared to the active participant. The mixed participant had high average minutes of MVPA yet lower pure and total movement dispersion values. Total movement dispersion had a significant correlation with average minutes of light PA (r = .406, p = .016) and average minutes of MVPA (r = .686, p < .001). Pure movement dispersion was significantly correlated with average minutes of light PA (r = .448, p = .008) and average minutes of MVPA (r = .599, p < .001). Average minutes of sedentary behavior (SB) were not significantly correlated with total (r = .041, p = .806) or pure movement dispersion (r = .165, p = .326).

PRACTICE IMPLICATIONS

Movement dispersion may provide another tool to advance knowledge of PA, potentially leading to improved health outcomes. Raw accelerometer data, such as that gathered at the elementary school in this study, offer opportunities to identify school-aged children at risk for obesity, SB, and lack of PA.

Regulation of Voluntary Physical Activity Behavior: A Review of Evidence Involving Dopaminergic Pathways in the Brain

Physical activity leads to well-established health benefits. Current efforts to enhance physical activity have targeted mainly socioeconomic factors. However, despite these efforts, only a small number of adults engage in regular physical activity to the point of meeting current recommendations. Evidence collected in rodent models and humans establish a strong central nervous system component that regulates physical activity behavior. In particular, dopaminergic pathways in the central nervous system are among the best-characterized biological mechanisms to date with respect to regulating reward, motivation, and habit formation, which are critical for establishing regular physical activity. Herein, we discuss evidence for a role of brain dopamine in the regulation of voluntary physical activity behavior based on selective breeding and pharmacological studies in rodents, as well as genetic studies in both rodents and humans. While these studies establish a role of dopamine and associated mechanisms in the brain in the regulation of voluntary physical activity behavior, there is clearly need for more research on the underlying biology involved in motivation for physical activity and the formation of a physical activity habit. Such knowledge at the basic science level may ultimately be translated into better strategies to enhance physical activity levels within the society.

Metabolic effects of prolactin and the role of dopamine agonists: A review

Prolactin is a polypeptide hormone that is well known for its role in reproductive physiology. Recent studies highlight its role in neurohormonal appetite regulation and metabolism. Elevated prolactin levels are widely associated with worsening metabolic disease, but it appears that low prolactin levels could also be metabolically unfavorable. This review discusses the pathophysiology of prolactin related metabolic changes, and the less commonly recognized effects of prolactin on adipose tissue, pancreas, liver, and small bowel. Furthermore, the effect of dopamine agonists on the metabolic profiles of patients with hyperprolactinemia are discussed as well.

Hypothalamus-skeletal muscle crosstalk during exercise and its role in metabolism modulation

Physical inactivity is a major public health problem that contributes to the development of several pathologies such as obesity, type 2 diabetes and cardiovascular diseases. Regular exercise mitigates the progression of these metabolic problems and contributes positively to memory and behavior. Therefore, public health agencies have incorporated exercise in the treatment of widespread disorders. The hypothalamus, specifically the ventromedial and the arcuate nuclei, responds to exercise activity and modulates energy metabolism through stimulation of the sympathetic nervous system and catecholamine secretion into the circulation. In addition, physical performance enhances cognitive functions and memory, mediated mostly by an increase in brain-derived neurotrophic factor levels in brain. During exercise training, skeletal muscle myofibers remodel their biochemical, morphological and physiological state. Moreover, skeletal muscle interacts with other organs by the release into the circulation of myokines, molecules that exhibit autocrine, paracrine and endocrine functions. Several studies have focused on the role of skeletal muscle and tissues in response to physical activity. However, how the hypothalamus could influence the skeletal muscle task in the context of exercise is less studied. Here, we review recent data about hypothalamus-skeletal muscle crosstalk in response to physical activity and focus on specific aspects such as the neuroendocrinological effects of exercise and the endocrine functions of skeletal muscle, to provide a perspective for future study directions.

The Role of Dopamine Receptor D2 in Bridging the Intention-Behavior Gap in Sport Participation

Previous studies have identified that a behavior can occur through the strongest predictor intention, but there is a gap between intention and behavior. Dopamine receptor D2 (DRD2) is known to account for a variance in sporting behaviors in human and animal subjects. However, the relationship between DRD2 and sport participation has been poorly studied, and the limited available reports are inconsistent. The present study was performed to examine the impact of DRD2 on sport participation among Korean university students based on the integrated behavioral model (IBM). Data were collected from enrolled university students in Seoul (N = 45). Participants answered survey questions first, and then they gave investigators their hair to provide DNA information (i.e., the A1 allele of DRD2). DRD2 had a significant effect on sport participation, but only in male students. Male students who carried the A1 allele of DRD2 significantly participated in 105.10 min more sporting activities than male students who did not. Moreover, the effect of intention on sport participation was significantly decreased when considering DRD2. Despite the small sample size, the results of this study could be a preliminary case for a larger study and indicate the direction of future research. Our results suggest that DRD2 may have played an important role as the “actual skill” shown in the IBM.

Peripheral BDNF and psycho-behavioral aspects are positively modulated by high-intensity intermittent exercise and fitness in healthy women

Acute high-intensity intermittent exercise (HIIE) induces the myokine secretion associated with neurogenesis, as well brain-derived neurotrophic factor (BDNF); however, it remains unknown how the menstrual phase influences this secretion after an acute exercise session. The current study aimed to investigate the effects of HIIE performed in luteal and follicular menstrual phases on BDNF, cognitive function, mood, and exercise enjoyment. Fourteen healthy women completed four experimental sessions, randomly. One graded exercise test (GXT) and one HIIE session (10 × 1-min runs 90% peak GXT velocity [1-min recovery]) were performed for each menstrual phase. Blood samples were collected at rest and immediately after efforts, and the profile of mood states questionnaire (POMS) and Stroop-task test were applied. During the HIIE, subjective scales were applied (feeling, felt arousal, rate of perceived exertion, and physical activity enjoyment). The main results showed that the serum BDNF presented no difference between menstrual phases (p = 0.870); however, HIIE increased BDNF concentration in both menstrual phases (p = 0.030). In addition, the magnitude of circulating BDNF variation (Δ%BDNF) and [Formula: see text] demonstrated an inverse relationship in the follicular phase (r =  - 0.539, p = 0.046), whereas in the luteal phase, Δ%BDNF was negatively correlated with time test (r =  - 0.684, p = 0.007) and RPE (r =  - 0.726, p = 0.004) in GXT. No differences between menstrual phases were observed for POMS (p ≥ 0.05); however, HIIE attenuated tension (p < 0.01), depression (p < 0.01), and anger moods (p < 0.01), independently of menstrual phases. The subjective scales and Stroop-task test did not show differences. In conclusion, menstrual cycle phase does not affect serum BDNF levels, cognitive function, mood, and exercise enjoyment. Contrary, HIIE increases peripheral BDNF and attenuates tension, depression, and anger independently of menstrual phase. In addition, Δ%BDNF was correlated with physical fitness in the follicular phase, exhibiting higher changes in women with lower physical fitness status.

Experimental dopaminergic neuron lesion at the area of the biological clock pacemaker, suprachiasmatic nuclei (SCN) induces metabolic syndrome in rats

BACKGROUND

The daily peak in dopaminergic neuronal activity at the area of the biological clock (hypothalamic suprachiasmatic nuclei [SCN]) is diminished in obese/insulin resistant vs lean/insulin sensitive animals. The impact of targeted lesioning of dopamine (DA) neurons specifically at the area surrounding (and that communicate with) the SCN (but not within the SCN itself) upon glucose metabolism, adipose and liver lipid gene expression, and cardiovascular biology in normal laboratory animals has not been investigated and was the focus of this study.

METHODS

Female Sprague-Dawley rats received either DA neuron neurotoxic lesion by bilateral intra-cannula injection of 6-hydroxydopamine (2-4 μg/side) or vehicle treatment at the area surrounding the SCN at 20 min post protriptyline ip injection (20 mg/kg) to protect against damage to noradrenergic and serotonergic neurons.

RESULTS

At 16 weeks post-lesion relative to vehicle treatment, peri-SCN area DA neuron lesioning increased weight gain (34.8%, P < 0.005), parametrial and retroperitoneal fat weight (45% and 90% respectively, P < 0.05), fasting plasma insulin, leptin and norepinephrine levels (180%, 71%, and 40% respectively, P < 0.05), glucose tolerance test area under the curve (AUC) insulin (112.5%, P < 0.05), and insulin resistance (44%-Matsuda Index, P < 0.05) without altering food consumption during the test period. Such lesion also induced the expression of several lipid synthesis genes in adipose and liver and the adipose lipolytic gene, hormone sensitive lipase in adipose (P < 0.05 for all). Liver monocyte chemoattractant protein 1 (a proinflammatory protein associated with metabolic syndrome) gene expression was also significantly elevated in peri-SCN area dopaminergic lesioned rats. Peri-SCN area dopaminergic neuron lesioned rats were also hypertensive (systolic BP rose from 157 ± 5 to 175 ± 5 mmHg, P < 0.01; diastolic BP rose from 109 ± 4 to 120 ± 3 mmHg, P < 0.05 and heart rate increase from 368 ± 12 to 406 ± 12 BPM, P < 0.05) and had elevated plasma norepinephrine levels (40% increased, P < 0.05) relative to controls.

CONCLUSIONS

These findings indicate that reduced dopaminergic neuronal activity in neurons at the area of and communicating with the SCN contributes significantly to increased sympathetic tone and the development of metabolic syndrome, without effect on feeding.

A nurse-led lifestyle intervention for adult persons with attention-deficit/hyperactivity disorder (ADHD) in Sweden

Introduction: Attention-deficit/hyperactivity disorder (ADHD) is associated with lifestyle-related diseases. Therefore, a nurse-led lifestyle intervention including interpersonal relationships, health education and cognitive support was developed to facilitate healthier lifestyle habits.Aim: The aim was to develop a lifestyle intervention and investigate its impact on mental and physical healthMethod: The 52-week intervention included 35 adults with ADHD. In a pre- and post-test design, symptoms of ADHD were measured with the Adult ADHD Self-Report Scale, quality of life was measured with the Adult ADHD Quality of Life scale and mental health was measured with the Hospital Anxiety and Depression scale. Lifestyle habits and dimensions of health were measured by the Lifestyle-Performance-Health Questionnaire and physical fitness was measured by the VO2 Max Test and calculations of waist circumference and body mass index. Result: Post-tests for a group of 25 persons showed positive changes following the intervention regarding weekly physical activity, quality of life and general and mental health. Lifestyle habit support was found to be important. The impact of the intervention should be confirmed in a long-term study with a control group.Conclusion: This intervention may be beneficial and may be implemented in a primary healthcare setting or in other open care units.

Sex differences in response to short-term high fat diet in mice

BACKGROUND

Consumption of high-fat diet (HF) leads to hyperphagia and increased body weight in male rodents. Female rodents are relatively resistant to hyperphagia and weight gain in response to HF, in part via effects of estrogen that suppresses food intake and increases energy expenditure. However, sex differences in energy expenditure and activity levels with HF challenge have not been systemically described. We hypothesized that, in response to short-term HF feeding, female mice will have a higher energy expenditure and be more resistant to HF-induced hyperphagia than male mice.

METHODS

Six-week-old male and female C57BL/6 J mice were fed either low fat (LF, 10% fat) or moderate HF (45% fat) for 5 weeks, and energy expenditure, activity and meal pattern measured using comprehensive laboratory animal monitoring system (CLAMS).

RESULTS

After 5 weeks, HF-fed male mice had a significant increase in body weight and fat mass, compared with LF-fed male mice. HF-fed female had a significant increase in body weight compared with LF-fed female mice, but there was no significant difference in fat mass. HF-fed male mice had lower energy expenditure compared to HF-fed female mice, likely due in part to reduced physical activity in the light phase. HF-fed male mice also had increased energy intake in the dark phase compared to LF-fed male mice and a reduced response to exogenous cholecystokinin-induced inhibition of food intake. In contrast, there was no difference in energy intake between LF-fed and HF-fed female mice.

CONCLUSIONS

The data show that female mice are generally protected from short-term HF-induced alterations in energy balance, possibly by maintaining higher energy expenditure and an absence of hyperphagia. However, HF-feeding in male mice induced weight and fat mass gain and hyperphagia. These findings suggest that there is a sex difference in the response to short-term HF-feeding in terms of both energy expenditure and control of food intake.

Aging Fits the Disease Criteria of the International Classification of Diseases

The disease criteria used by the World Health Organization (WHO) were applied to human biological aging in order to assess whether aging can be classified as a disease. These criteria were developed for the 11th revision of the International Classification of Diseases (ICD) and included disease diagnostics, mechanisms, course and outcomes, known interventions, and linkage to genetic and environmental factors. RESULTS: Biological aging can be diagnosed with frailty indices, functional, blood-based biomarkers. A number of major causal mechanisms of human aging involved in various organs have been described, such as inflammation, replicative cellular senescence, immune senescence, proteostasis failures, mitochondrial dysfunctions, fibrotic propensity, hormonal aging, body composition changes, etc. We identified a number of clinically proven interventions, as well as genetic and environmental factors of aging. Therefore, aging fits the ICD-11 criteria and can be considered a disease. Our proposal was submitted to the ICD-11 Joint Task force, and this led to the inclusion of the extension code for "Ageing-related" (XT9T) into the "Causality" section of the ICD-11. This might lead to greater focus on biological aging in global health policy and might provide for more opportunities for the new therapy developers.

Time for a New Perspective on Prolactin in Metabolism

The pituitary hormone prolactin (PRL) regulates a variety of functions beyond reproduction. The association between physiological (pregnancy) and pathological (prolactinoma) hyperprolactinemia and metabolic alterations led to the concept of this hormone being diabetogenic. However, large cohort clinical studies have recently shown that low circulating PRL levels are associated with metabolic disease and represent a risk factor for type 2 diabetes (T2D), whereas high PRL levels are beneficial. Moreover, PRL acts on the pancreas, liver, adipose tissue, and hypothalamus to maintain and promote metabolic homeostasis. By integrating basic and clinical evidence, we hypothesize that upregulation of PRL levels is a mechanism to maintain metabolic homeostasis and, thus, propose that the range of PRL levels considered physiological should be expanded to higher values.

Physical Activity and Brain Health

Physical activity (PA) has been central in the life of our species for most of its history, and thus shaped our physiology during evolution. However, only recently the health consequences of a sedentary lifestyle, and of highly energetic diets, are becoming clear. It has been also acknowledged that lifestyle and diet can induce epigenetic modifications which modify chromatin structure and gene expression, thus causing even heritable metabolic outcomes. Many studies have shown that PA can reverse at least some of the unwanted effects of sedentary lifestyle, and can also contribute in delaying brain aging and degenerative pathologies such as Alzheimer’s Disease, diabetes, and multiple sclerosis. Most importantly, PA improves cognitive processes and memory, has analgesic and antidepressant effects, and even induces a sense of wellbeing, giving strength to the ancient principle of “mens sana in corpore sano” (i.e., a sound mind in a sound body). In this review we will discuss the potential mechanisms underlying the effects of PA on brain health, focusing on hormones, neurotrophins, and neurotransmitters, the release of which is modulated by PA, as well as on the intra- and extra-cellular pathways that regulate the expression of some of the genes involved.

Functional hypothalamic and drug-induced amenorrhea: an overview

BACKGROUND

Functional hypothalamic amenorrhea (FHA) is a form of chronic anovulation not due to identifiable organic causes and with adverse health consequences. The identification of women with this disorder or the precocious identification of women at risk is based on the knowledge of lifestyle risk factors or behaviors such as stress, weight loss, and excessive physical exercise that are known to negatively impact gonadal axis activity.

METHODS

In this overview, we described the most common forms of FHA, in particular stress-induced amenorrhea and overtraining-induced amenorrhea. In addition, although its mechanisms can differ from those involved in FHA, we reviewed the available literature on drug-induced amenorrhea, highlighting the clear connection between this condition and psychoactive drugs such as antipsychotics, antidepressants and anti-epilectics thus raising concern about the role that the abuse of substances such as opioids or alcohol can possibly have on the growing unexplained infertility of the female population.

Stay Fit, Stay Young: Mitochondria in Movement: The Role of Exercise in the New Mitochondrial Paradigm

Skeletal muscles require the proper production and distribution of energy to sustain their work. To ensure this requirement is met, mitochondria form large networks within skeletal muscle cells, and during exercise, they can enhance their functions. In the present review, we discuss recent findings on exercise-induced mitochondrial adaptations. We emphasize the importance of mitochondrial biogenesis, morphological changes, and increases in respiratory supercomplex formation as mechanisms triggered by exercise that may increase the function of skeletal muscles. Finally, we highlight the possible effects of nutraceutical compounds on mitochondrial performance during exercise and outline the use of exercise as a therapeutic tool in noncommunicable disease prevention. The resulting picture shows that the modulation of mitochondrial activity by exercise is not only fundamental for physical performance but also a key point for whole-organism well-being.

Making sense of gut feelings in the traumatic brain injury pathogenesis

Traumatic brain injury (TBI) is a devastating condition which often initiates a sequel of neurological disorders that can last throughout lifespan. From metabolic perspective, TBI also compromises systemic physiology including the function of body organs with subsequent malfunctions in metabolism. The emerging panorama is that the effects of TBI on the periphery strike back on the brain and exacerbate the overall TBI pathogenesis. An increasing number of clinical reports are alarming to show that metabolic dysfunction is associated with incidence of long-term neurological and psychiatric disorders. The autonomic nervous system, associated hypothalamic-pituitary axis, and the immune system are at the center of the interface between brain and body and are central to the regulation of overall homeostasis and disease. We review the strong association between mechanisms that regulate cell metabolism and inflammation which has important clinical implications for the communication between body and brain. We also discuss the integrative actions of lifestyle interventions such as diet and exercise on promoting brain and body health and cognition after TBI.

Correlates of Physical Activity Among Middle-Aged and Older Adults With Hazardous Drinking Habits in Six Low- and Middle-Income Countries

We investigated physical activity (PA) correlates among middle-aged and older adults (aged ≥50 years) with hazardous drinking patterns in six low- and middle-income countries. Cross-sectional data were analyzed from the World Health Organization's Study on Global Ageing and Adult Health. Hazardous drinking was defined as consuming >7 (females) or >14 (males) standard drinks per week. Participants were dichotomized into low (i.e., not meeting 150 min of moderate PA/week) and moderate-high physically active groups. Associations between PA and a range of correlates were examined using multivariable logistic regressions. The prevalence of low PA in 1,835 hazardous drinkers (60.5 ± 13.1 years; 87.9% males) was 16.2% (95% confidence interval [13.9%, 18.9%]). Older age, living in an urban setting, being unemployed, depression, underweight, obesity, asthma, visual impairment, poor self-rated health, and higher levels of disability were identified as significant PA correlates. The current data provide important guidance for future interventions to assist older hazardous drinkers to engage in regular PA.

Mapping brown adipose tissue based on fat water fraction provided by Z-spectral imaging

BACKGROUND

Brown adipose tissue (BAT) has a great relevance in metabolic diseases and has been shown to be reduced in obesity and insulin resistance patients. Currently, Dixon MRI is used to calculate fat-water fraction (FWF) and differentiate BAT from white adipose tissue (WAT). However, it may fail in areas of phase wrapping and introduce fat-water swapping artifacts.

PURPOSE

To investigate the capacity of the Z-spectrum imaging (ZSI) for the identification of BAT in vivo.

STUDY TYPE

Retrospective study.

SPECIMENS

WAT, BAT, and lean tissue from healthy mice.

ANIMALS

Four C57BL/6 healthy mice.

POPULATION

Five healthy volunteers.

FIELD STRENGTH

9.4T, 3T for volunteers.

SEQUENCE

Z-Spectra data were fitted to a model with three Lorentzian peaks reflecting the direct saturation of tissue water (W) and methylene fat (F), and the magnetization transfer from the semi-solid tissues. The peak amplitudes of water and fat were used to map the FWF. The novel FWF metric was calibrated with an oil and water mixture phantom and validated in specimens, mice and human subjects.

ASSESSMEMT

FWF distribution was compared with published works and values compared with Dixon's MRI results.

STATISTICAL TESTS

Comparisons were performed by t-tests.

RESULTS

ZSI clearly differentiated WAT, BAT, and lean tissues by having FWF = 1, 0.5, and 0, respectively. Calibration with oil mixture phantoms revealed a linear relationship between FWF and the actual fat fraction (R2  = 0.98). In vivo experiments in mice confirmed in vitro results by showing FWF = 0.6 in BAT. FWF maps of human subjects showed the same FWF distribution as Dixon's MRI (P > 0.05). ZSI is independent from B0 field inhomogeneity and fat-water swapping because both lipid and water frequency offsets are determined simultaneously during Z-spectral fitting.

DATA CONCLUSION

ZSI can derive artifact-free FWF maps, which can be used to identify BAT distribution in vivo noninvasively.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1527-1533.

Exercise, Obesity and CNS Control of Metabolic Homeostasis: A Review

This review details the manner in which the central nervous system regulates metabolic homeostasis in normal weight and obese rodents and humans. It includes a review of the homeostatic contributions of neurons located in the hypothalamus, the midbrain and limbic structures, the pons and the medullary area postrema, nucleus tractus solitarius, and vagus nucleus, and details how these brain regions respond to circulating levels of orexigenic hormones, such as ghrelin, and anorexigenic hormones, such as glucagon-like peptide 1 and leptin. It provides an insight as to how high intensity exercise may improve homeostatic control in overweight and obese subjects. Finally, it provides suggestions as to how further progress can be made in controlling the current pandemic of obesity and diabetes.

Voluntary exercise and depression-like behavior in rodents: are we running in the right direction?

Acute or chronic exposure to stress can increase the risk to develop major depressive disorder, a severe, recurrent and common psychiatric condition. Depression places an enormous social and financial burden on modern society. Although many depressed patients are treated with antidepressants, their efficacy is only modest, underscoring the necessity to develop clinically effective pharmaceutical or behavioral treatments. Exercise training produces beneficial effects on stress-related mental disorders, indicative of clinical potential. The pro-resilient and antidepressant effects of exercise training have been documented for several decades. Nonetheless, the underlying molecular mechanisms and the brain circuitries involved remain poorly understood. Preclinical investigations using voluntary wheel running, a frequently used rodent model that mimics aspects of human exercise training, have started to shed light on the molecular adaptations, signaling pathways and brain nuclei underlying the beneficial effects of exercise training on stress-related behavior. In this review, I highlight several neurotransmitter systems that are putative mediators of the beneficial effects of exercise training on mental health, and review recent rodent studies that utilized voluntary wheel running to promote our understanding of exercise training-induced central adaptations. Advancements in our mechanistic understanding of how exercise training induces beneficial neuronal adaptations will provide a framework for the development of new strategies to treat stress-associated mental illnesses.

Correlates of physical activity among community-dwelling adults aged 50 or over in six low- and middle-income countries

BACKGROUND

Considering that physical activity is associated with healthy ageing and helps to delay, prevent, or manage a plethora of non-communicable diseases in older adults, there is a need to investigate the factors that influence physical activity participation in this population. Thus, we investigated physical activity correlates among community-dwelling older adults (aged ≥50 years) in six low- and middle-income countries.

METHODS

Cross-sectional data were analyzed from the World Health Organization's Study on Global Ageing and Adult Health. Physical activity was assessed by the Global Physical Activity Questionnaire. Participants were dichotomized into low (i.e., not meeting 150 minutes of moderate physical activity per week) and moderate-to-high physically active groups. Associations between physical activity and a range of correlates were examined using multivariable logistic regressions.

RESULTS

The overall prevalence (95%CI) of people not meeting recommended physical activity levels in 34,129 participants (mean age 62.4 years, 52.1% female) was 23.5% (22.3%-24.8%). In the multivariable analysis, older age and unemployment were significant sociodemographic correlates of low physical activity. Individuals with low body mass index (<18.5kg/m2), bodily pain, asthma, chronic back pain, chronic obstructive pulmonary disease, hearing problems, stroke, visual impairment, slow gait, and weak grip strength were less likely to meet physical activity targets in the overall sample (P<0.05). The associations varied widely between countries.

CONCLUSION

Our data illustrates that a multitude of factors influence physical activity target achievement in older adults, which can inform future interventions across low- and middle-income countries to assist people of this age group to engage in regular physical activity. Future prospective cohort studies are also required to investigate the directionality and mediators of the relationships observed.

Maternal Western diet age-specifically alters female offspring voluntary physical activity and dopamine- and leptin-related gene expression

Prenatal overnutrition affects development into adulthood and influences risk of obesity. We assessed the transgenerational effect of maternal Western diet (WD) consumption on offspring physical activity. Voluntary wheel running was increased in juvenile (4-7 wk of age), but decreased in adult (16-19 wk of age), F₁ female WD offspring In contrast, no wheel-running differences in F₁ male offspring were observed. Increased wheel running in juvenile female WD offspring was associated with up-regulated dopamine receptor (DRD)-1 and -2 in the nucleus accumbens (NAc) and with down-regulated Lepr in the ventral tegmental area (VTA). Conversely, decreased wheel running by adult female WD offspring was associated with down-regulated DRD1 in the NAc and with up-regulated Lepr in the VTA. Body fat, leptin, and insulin were increased in male, but not in female, F₁ WD offspring. Recombinant virus (rAAV) leptin antagonism in the VTA decreased wheel running in standard diet but not in WD F₁ female offspring. Analysis of F₂ offspring found no differences in wheel running or adiposity in male or female offspring, suggesting that changes in the F₁ generation were related to in utero somatic reprogramming. Our findings indicate prenatal WD exposure leads to age-specific changes in voluntary physical activity in female offspring that are differentially influenced by VTA leptin antagonism.-Ruegsegger, G. N., Grigsby, K. B., Kelty, T. J., Zidon, T. M., Childs, T. E., Vieira-Potter, V. J., Klinkebiel, D. L., Matheny, M., Scarpace, P. J., Booth, F. W. Maternal Western diet age-specifically alters female offspring voluntary physical activity and dopamine- and leptin-related gene expression.