Dopaminergic Control of the Feeding Circuit

Excessive body weight and its contributing factors in visually impaired patients in northwest Ethiopia, 2024

Background

Excessive body weight are global health challenge affecting individuals across all age groups. They result from an imbalance between calorie intake and expenditure. Individuals with visual impairment are particularly vulnerable due to reduced physical activity, leading to higher rates of excessive body weight. This study assessed the prevalence and determinants of excessive body weight among visually impaired patients in northwest Ethiopia in 2024.

Method

A multi-centered institution-based cross-sectional study was done with 384 visually impaired patients selected using a simple random sample technique. An interviewer-administered structured questionnaire and physical assessments were used to gather data. The crude and adjusted odds ratios, as well as the 95% confidence intervals, were calculated. Bivariate and multivariate logistic regression analyses were performed. Variables having a p-value < 0.05 were considered substantially associated with excessive body weight.

Results

The prevalence of excessive body weight was 27.9% (95% CI: 23.2-32.8). Factors significantly associated with excessive body weight included being aged 65 or older (AOR = 5.43, 95% CI: 1.22-24.1), urban residency (AOR = 4.84, 95% CI: 2.95-7.95), and having visual impairment for five or more years (AOR = 3.33, 95% CI: 1.88-5.89).

Conclusion

Excessive body weight affects nearly one-third of visually impaired patients in northwest Ethiopia, with significant associations found for older age, urban residence, and long-term visual impairment. Integrating weight management programs, physical activity promotion, nutritional education, and community support is essential to improve health outcomes. Future studies using prospective cohort designs are recommended to explore causal relationships.

Exploring the genetic contribution in obesity: An overview of dopaminergic system genes

Obesity is a widespread global health concern that affects a significant portion of the population and is associated with reduced quality of life, morbidity, and mortality. It is considered a pandemic, with its prevalence constantly rising in Western countries. As a result, numerous studies have focused on understanding the elements that contribute to obesity. Researchers have focused on neurotransmitters in the brain to develop weight management drugs that regulate food intake. This review explores the literature on genetic influences on dopaminergic processes to determine whether genetic variation has an association with obesity in reward-responsive regions, including mesolimbic efferent and mesocortical areas. Various neurotransmitters play an essential role in regulating food intake, such as dopamine which controls through mesolimbic circuits in the brain that modulate food reward. Appetite stimulation, including primary reinforcers such as food, leads to an increase in dopamine release in the reward centers of the brain. This release is related to motivation and reinforcement, which determines the motivational weighting of the reinforcer. Changes in dopamine expression can lead to hedonic eating behaviors and contribute to the development of obesity. Genetic polymorphisms have been investigated due to their potential role in modulating the risk of obesity and eating behaviors. Therefore, it is crucial to assess the impact of genetic alterations that disrupt this pathway on the obesity phenotype.

The Hypothalamic Arcuate Nucleus Dopaminergic Neurons: More Than Just Prolactin Secretion

The hypothalamic arcuate nucleus dopaminergic (A12) neurons are well known for their central role in regulating prolactin secretion through a sophisticated negative feedback loop. In this canonical pathway, prolactin stimulates A12 neurons to release dopamine, which suppresses further prolactin release from lactotrophs in the anterior pituitary. However, a collective of recent and past evidence strongly implies that the A12 neurons are far more dynamic and multifaceted than previously appreciated. This minireview discusses the developmental trajectory of A12 neurons, from prenatal origins to postnatal maturation, highlighting their diversity and heterogeneity. Beyond their well-characterized role in prolactin regulation, the A12 neurons contribute to a broader array of hypothalamic functions, including autoregulation, metabolism, and growth. By shedding light on these underexplored roles, this review outlines the expansive significance of A12 neurons as more than mere gatekeepers of prolactin secretion, positioning them as versatile players in endocrine and metabolic homeostasis.

Leaky Gut Syndrome: An Interplay Between Nutrients and Dysbiosis

PURPOSE OF REVIEW

The gut microbiota (GM) is directly related to health and disease. In this context, disturbances resulting from excessive stress, unbalanced diet, alcohol abuse, and antibiotic use, among other factors, can contribute to microbiota imbalance, with significant impacts on host health. This review provides a comprehensive examination of the literature on the influence of diet on dysbiosis and increased intestinal permeability over the past five years.

RECENT FINDINGS

Diet can be considered one of the main modulating factors of GM, impacting its composition and functionality. Excessive consumption of simple carbohydrates, saturated fats, and processed foods appears to be directly linked to dysbiosis, which can lead to intestinal hyperpermeability and leaky gut syndrome. On the other hand, diets primarily composed of food groups such as nuts, vegetables, fruits, fish, and poultry in moderate quantities, along with limited consumption of red and processed meats, are associated with a more diverse, healthier, and beneficial GM for the host. It is worth noticing that the use of prebiotics and probiotics, omega-3 supplementation, polyunsaturated fatty acids, and vitamins A, B, C, D, and E can positively modulate the intestinal microbiota by altering its metabolic activity, microbial composition, and improve intestinal barrier function. This review points to a new perspective regarding individualized dietary intervention and the need to integrate it into several aspects of cellular biology, biochemistry, and microbiology to prescribe more effective diets and thus contribute to patients' comprehensive health.

Central administration of galanin-like peptide (GALP) causes short-term orexigenic effects in broilers: Mediatory role of NPY1 and D1 receptors

Studies conducted on mammalian models have indicated the role of galanin-like peptide (GALP) in appetite regulation. For the first time, the present study examines the effects of this peptide on feed consumption and behavioral changes, as well as its interaction with dopaminergic and neuropeptide Y (NPY) systems in broilers. In experiment 1, broilers were injected with GALP (0.5, 1, and 2 μg) and saline. In experiment 2, saline, NPY1 receptor antagonist (BIBO-3304), GALP (2 μg), and BIBO-3304 + GALP were administrated. Experiments 3-6 were identical to experiment 2, except that NPY2 receptor antagonist (BIIE 0246), NPY5 receptor antagonist (CGP 71683A), D1 receptor antagonist (SCH39166), and D2 receptor antagonist (L-741,626) were injected instead of BIBO-3304. After that, cumulative meal consumption was recorded for 2 h. Also, behavioral changes in the broilers receiving GALP (0.5, 1, and 2 μg) were monitored for thirty minutes after infusion. Following the administration of GALP (1 and 2 μg), food intake and the number of feeding and exploratory pecks of chicks increased (P < 0.05), while other behaviors did not change significantly (P ≥  0.05). Co-infusion of BIBO-3304 + GALP suppressed the orexigenic effect of GALP (P < 0.05). Infusion of BIIE 0246, CGP 71683A, and L-741,626 with GALP, had no significant effect on GALP-induced hyperphagia (P ≥  0.05). However, the orexigenic effects of GALP were stimulated following the co-administration of SCH39166A + GALP (P < 0.05). These findings indicate that NPY1 and D1 receptors can mediate GALP-induced hyperphagia in broilers.

Neurocognitive impairments in rat offspring after maternal exposure to vortioxetine: Involvement of BDNF, apoptosis and cholinergic mediated signaling pathways

Depression in pregnant women raises concerns about the safety of antidepressants use, particularly its impact on offspring's neurocognition. This study investigates the effects of maternal exposure to vortioxetine (VOX) on the neurocognitive development of rat offspring. Pregnant Wistar rats were administered clinically pertinent doses of VOX, 1 mg/kg/day or 2 mg/kg/day from gestational day 6-21. The dams delivered their offspring naturally and reared until postnatal day (PND) 70. Offspring of both sexes were assessed for postnatal growth by measuring body weight from PND 1-70 weekly and cognitive function using Morris water maze (MWM) test and passive avoidance learning test from PND 49-70. After behavioral assessments, adult rat offspring were sacrificed, and their brains were dissected out for assessment of brain morphology as well as biochemical analysis. The results demonstrated that VOX exposure potentially impaired cognitive performance, evidenced by increased latency in MWM and passive avoidance learning tests. Additionally, it led to decreased body weight, altered brain morphology, and disrupted neurobiochemical profiles. Specifically, VOX 2 mg/kg exposure significantly reduced brain-derived neurotrophic factor (BDNF) expression, increased pro-apoptotic BAX expression, decreased anti-apoptotic Bcl-2 expression, and elevated acetylcholinesterase (AChE) activity in the hippocampus. Lower dose of VOX (1 mg/kg) did not show significant adverse effects on neurocognition, suggesting a dose-dependent impact. No sex specific neurocognitive deficits were observed in current study. These findings indicate that while VOX may offer a safer profile compared to SSRIs, high doses during pregnancy can still result in neurocognitive impairments in offspring.

Dopamine-Sensitive Anterior Cingulate Cortical Glucose-Monitoring Neurons as Potential Therapeutic Targets for Gustatory and Other Behavior Alterations

Background: The anterior cingulate cortex (ACC) is known for its involvement in various regulatory functions, including in the central control of feeding. Activation of local elements of the central glucose-monitoring (GM) neuronal network appears to be indispensable in these regulatory processes. Destruction of these type 2 glucose transporter protein (GLUT2)-equipped chemosensory cells results in multiple feeding-associated functional alterations. Methods: In order to examine this complex symptomatology, (1) dopamine sensitivity was studied in laboratory rats by means of the single-neuron-recording multibarreled microelectrophoretic technique, and (2) after local bilateral microinjection of the selective type 2 glucose transporter proteindemolishing streptozotocin (STZ), open-field, elevated plus maze, two-bottle and taste reactivity tests were performed. Results: A high proportion of the anterior cingulate cortical neurons changed their firing rate in response to microelectrophoretic administration of D-glucose, thus verifying them as local elements of the central glucose-monitoring network. Approximately 20% of the recorded cells displayed activity changes in response to microelectrophoretic application of dopamine, and almost 50% of the glucose-monitoring units here proved to be dopamine-sensitive. Moreover, taste stimulation experiments revealed even higher (80%) gustatory sensitivity dominance of these chemosensory cells. The anterior cingulate cortical STZ microinjections resulted in extensive behavioral and taste-associated functional deficits. Conclusions: The present findings provided evidence for the selective loss of glucose-monitoring neurons in the anterior cingulate cortex leading to motivated behavioral and gustatory alterations. This complex dataset also underlines the varied significance of the type 2 glucose transporter protein-equipped, dopamine-sensitive glucose-monitoring neurons as potential therapeutic targets. These units appear to be indispensable in adaptive control mechanisms of the homeostatic-motivational-emotional-cognitive balance for the overall well-being of the organism.

Stimulation of Dopamine D4 Receptors in the Nucleus Accumbens Shell Increases Palatable Food Intake in Satiated Male Rats: Modulation by NMDA and AMPA Receptors

BACKGROUND/OBJECTIVES

Palatability significantly influences food consumption, often leading to overeating and obesity by activating the brain's reward systems. The nucleus accumbens (NAc) plays a central role in this process, modulating reward mechanisms primarily via dopamine through D2-like receptors (D2R, D3R, D4R). While the involvement of D2 receptors in feeding is well-documented, the role of D4 receptors (D4Rs) is less clear.

METHODS

Male Wistar rats received intra-NAc shell microinjections of the D4R agonist PD-168077 and the antagonist L-745870. This study also examined the modulation between D4R and glutamatergic transmission by administration of NMDA, NMDA receptor antagonist AP-5, AMPA, and AMPA receptor antagonist CNQX.

RESULTS

PD-168077 increased sweet solution intake by 46%, an effect that was reversed by L-745870. Pre-treatment with NMDA prevented the stimulatory effect of PD-168077, whereas the NMDA receptor antagonist AP-5 had no such effect. Additionally, AMPA administration reduced sweet solution intake by 63%, counteracting the effect of PD-168077, while the AMPA receptor antagonist CNQX, on its own, increased intake by 40%.

CONCLUSIONS

These findings suggest that D4Rs promote hedonic feeding by modulating glutamatergic transmission in the NAc shell, highlighting the complexity of D4R involvement in food intake regulation. This study underscores the potential of targeting D4Rs for therapeutic interventions in eating disorders and obesity, though further research is essential to clarify the precise mechanisms through which D4R modulates AMPA and NMDA receptor activity in feeding behavior.

Lack of Bmal1 leads to changes in rhythmicity and impairs motivation towards natural stimuli

Maintaining proper circadian rhythms is essential for coordinating biological functions in mammals. This study investigates the effects of daily arrhythmicity using Bmal1-knockout (KO) mice as a model, aiming to understand behavioural and motivational implications. By employing a new mathematical analysis based on entropy divergence, we identified disrupted intricate activity patterns in mice derived by the complete absence of BMAL1 and quantified the difference regarding the activity oscillation's complexity. Changes in locomotor activity coincided with disturbances in circadian gene expression patterns. Additionally, we found a dysregulated gene expression profile particularly in brain nuclei like the ventral striatum, impacting genes related to reward and motivation. Further investigation revealed that arrhythmic mice exhibited heightened motivation for food and water rewards, indicating a link between circadian disruptions and the reward system. This research sheds light on how circadian clock alterations impact the gene expression regulating the reward system and how this, in turn, can lead to altered seeking behaviour and motivation for natural rewards. In summary, the present study contributes to our understanding of how reward processing is under the regulation of circadian clock machinery.

Repeated binge-like eating episodes in female rats alter adenosine A2A and dopamine D2 receptor genes regulation in the brain reward system

OBJECTIVE

Binge-eating disorder is an eating disorder characterized by recurrent binge-eating episodes, during which individuals consume excessive amounts of highly palatable food (HPF) in a short time. This study investigates the intricate relationship between repeated binge-eating episode and the transcriptional regulation of two key genes, adenosine A2A receptor (A2AAR) and dopamine D2 receptor (D2R), in selected brain regions of rats.

METHOD

Binge-like eating behavior on HPF was induced through the combination of food restrictions and frustration stress (15 min exposure to HPF without access to it) in female rats, compared to control rats subjected to only restriction or only stress or none of these two conditions. After chronic binge-eating episodes, nucleic acids were extracted from different brain regions, and gene expression levels were assessed through real-time quantitative PCR. The methylation pattern on genes' promoters was investigated using pyrosequencing.

RESULTS

The analysis revealed A2AAR upregulation in the amygdala and in the ventral tegmental area (VTA), and D2R downregulation in the nucleus accumbens in binge-eating rats. Concurrently, site-specific DNA methylation alterations at gene promoters were identified in the VTA for A2AAR and in the amygdala and caudate putamen for D2R.

DISCUSSION

The alterations on A2AAR and D2R genes regulation highlight the significance of epigenetic mechanisms in the etiology of binge-eating behavior, and underscore the potential for targeted therapeutic interventions, to prevent the development of this maladaptive feeding behavior. These findings provide valuable insights for future research in the field of eating disorders.

PUBLIC SIGNIFICANCE

Using an animal model with face, construct, and predictive validity, in which cycles of food restriction and frustration stress evoke binge-eating behavior, we highlight the significance of epigenetic mechanisms on adenosine A2A receptor (A2AAR) and dopamine D2 receptor (D2R) genes regulation. They could represent new potential targets for the pharmacological management of eating disorders characterized by this maladaptive feeding behavior.

Traditional Japanese medicine Kamikihito ameliorates sucrose preference, chronic inflammation and obesity induced by a high fat diet in middle-aged mice

The high prevalence of obesity has become a pressing global public health problem and there exists a strong association between increased BMI and mortality at a BMI of 25 kg/m2 or higher. The prevalence of obesity is higher among middle-aged adults than among younger groups and the combination of aging and obesity exacerbate systemic inflammation. Increased inflammatory cytokines such as interleukin 6 and tumor necrosis factor alpha (TNFα) are hallmarks of obesity, and promote the secretion of hepatic C-reactive protein (CRP) which further induces systematic inflammation. The neuropeptide oxytocin has been shown to have anti-obesity and anti-inflammation effects, and also suppress sweet-tasting carbohydrate consumption in mammals. Previously, we have shown that the Japanese herbal medicine Kamikihito (KKT), which is used to treat neuropsychological stress disorders in Japan, functions as an oxytocin receptors agonist. In the present study, we further investigated the effect of KKT on body weight (BW), food intake, inflammation, and sweet preferences in middle-aged obese mice. KKT oral administration for 12 days decreased the expression of pro-inflammatory cytokines in the liver, and the plasma CRP and TNFα levels in obese mice. The effect of KKT administration was found to be different between male and female mice. In the absence of sucrose, KKT administration decreased food intake only in male mice. However, while having access to a 30% sucrose solution, both BW and food intake was decreased by KKT administration in male and female mice; but sucrose intake was decreased in female mice alone. In addition, KKT administration decreased sucrose intake in oxytocin deficient lean mice, but not in the WT lean mice. The present study demonstrates that KKT ameliorates chronic inflammation, which is strongly associated with aging and obesity, and decreases food intake in male mice as well as sucrose intake in female mice; in an oxytocin receptor dependent manner.

The Calmodulin-interacting peptide Pcp4a regulates feeding state-dependent behavioral choice in zebrafish

Animals constantly need to judge the valence of an object in their environment: is it potential food or a threat? The brain makes fundamental decisions on the appropriate behavioral strategy by integrating external information from sensory organs and internal signals related to physiological needs. For example, a hungry animal may take more risks than a satiated one when deciding to approach or avoid an object. Using a proteomic profiling approach, we identified the Calmodulin-interacting peptide Pcp4a as a key regulator of foraging-related decisions. Food intake reduced abundance of protein and mRNA of pcp4a via dopamine D2-like receptor-mediated repression of adenylate cyclase. Accordingly, deleting the pcp4a gene made zebrafish larvae more risk averse in a binary decision assay. Strikingly, neurons in the tectum became less responsive to prey-like visual stimuli in pcp4a mutants, thus biasing the behavior toward avoidance. This study pinpoints a molecular mechanism modulating behavioral choice according to internal state.

Maternal nanoplastic ingestion induces an increase in offspring body weight through altered lipid species and microbiota

The rapidly increasing prevalence of obesity and overweight, especially in children and adolescents, has become a serious societal issue. Although various genetic and environmental risk factors for pediatric obesity and overweight have been identified, the problem has not been solved. In this study, we examined whether environmental nanoplastic (NP) pollutants can act as environmental obesogens using mouse models exposed to NPs derived from polystyrene and polypropylene, which are abundant in the environment. We found abnormal weight gain in the progeny until 6 weeks of age following the oral administration of NPs to the mother during gestation and lactation. Through a series of experiments involving multi-omic analyses, we have demonstrated that NP-induced weight gain is caused by alterations in the lipid composition (lysophosphatidylcholine/phosphatidylcholine ratio) of maternal breast milk and he gut microbiota distribution of the progeny. These data indicate that environmental NPs can act as obesogens in childhood.

Satiety: a gut-brain-relationship

Many hormones act on the hypothalamus to control hunger and satiety through various pathways closely associated with several factors. When food is present in the gastro intestinal (GI) tract, enteroendocrine cells (EECs) emit satiety signals such as cholecystokinin (CCK), glucagon like peptide-1 (GLP-1) and peptide YY (PYY), which can then communicate with the vagus nerve to control food intake. More specifically, satiety has been shown to be particularly affected by the GLP-1 hormone and its receptor agonists that have lately been acknowledged as a promising way to reduce weight. In addition, there is increasing evidence that normal flora is also involved in the peripheral, central, and reward system that impact satiety. Moreover, neurologic pathways control satiety through neurotransmitters. In this review, we discuss the different roles of each of the GLP-1 hormone and its agonist, gut microbiomes, as well as neurotransmitters and their interconnected relation in the regulation of body's satiety homeostasis.

Maternal Over- and Malnutrition and Increased Risk for Addictive and Eating Disorders in the Offspring

Evidence from human and animal studies has shown that maternal overnutrition and/or obesity are linked with neurobehavioral changes in the offspring. This fetal programming is characterized by adaptive responses to changes in the nutritional state during early life. In the past decade, an association has been made between overconsumption of highly-palatable food by the mother during fetal development and abnormal behaviors resembling addiction in the offspring. Maternal overnutrition can lead to alterations in the offspring's brain reward circuitry leading to hyperresponsiveness of this circuit following exposure to calorie-dense foods later in life. Given the accumulating evidence indicating that the central nervous system plays a pivotal role in regulating food intake, energy balance, and the motivation to seek food, a dysfunction in the reward circuitry may contribute to the addiction-like behaviors observed in the offspring. However, the underlying mechanisms leading to these alterations in the reward circuitry during fetal development and their relevance to the increased risk for the offspring to later develop addictive-like behaviors is still unclear. Here, we review the most relevant scientific reports about the impact of food overconsumption during fetal development and its effect on addictive-like behaviors of the offspring in the context of eating disorders and obesity.

Suprachiasmatic to paraventricular nuclei interaction generates normal food searching rhythms in mice

Searching for food follows a well-organized decision process in mammals to take up food only if necessary. Moreover, scavenging is preferred during their activity phase. Various time-dependent regulatory processes have been identified originating from the suprachiasmatic nuclei (SCN), which convert external light information into synchronizing output signals. However, a direct impact of the SCN on the timing of normal food searching has not yet been found. Here, we revisited the function of the SCN to affect when mice look for food. We found that this process was independent of light but modified by the palatability of the food source. Surprisingly, reducing the output from the SCN, in particular from the vasopressin releasing neurons, reduced the amount of scavenging during the early activity phase. The SCN appeared to transmit a signal to the paraventricular nuclei (PVN) via GABA receptor A1. Finally, the interaction of SCN and PVN was verified by retrograde transport-mediated complementation. None of the genetic manipulations affected the uptake of more palatable food. The data indicate that the PVN are sufficient to produce blunted food searching rhythms and are responsive to hedonistic feeding. Nevertheless, the search for normal food during the early activity phase is significantly enhanced by the SCN.

Dopamine systems and biological rhythms: Let's get a move on

How dopamine signaling regulates biological rhythms is an area of emerging interest. Here we review experiments focused on delineating dopamine signaling in the suprachiasmatic nucleus, nucleus accumbens, and dorsal striatum to mediate a range of biological rhythms including photoentrainment, activity cycles, rest phase eating of palatable food, diet-induced obesity, and food anticipatory activity. Enthusiasm for causal roles for dopamine in the regulation of circadian rhythms, particularly those associated with food and other rewarding events, is warranted. However, determining that there is rhythmic gene expression in dopamine neurons and target structures does not mean that they are bona fide circadian pacemakers. Given that dopamine has such a profound role in promoting voluntary movements, interpretation of circadian phenotypes associated with locomotor activity must be differentiated at the molecular and behavioral levels. Here we review our current understanding of dopamine signaling in relation to biological rhythms and suggest future experiments that are aimed at teasing apart the roles of dopamine subpopulations and dopamine receptor expressing neurons in causally mediating biological rhythms, particularly in relation to feeding, reward, and activity.

Obesity I: Overview and molecular and biochemical mechanisms

Obesity is a chronic, relapsing condition characterized by excess body fat. Its prevalence has increased globally since the 1970s, and the number of obese and overweight people is now greater than those underweight. Obesity is a multifactorial condition, and as such, many components contribute to its development and pathogenesis. This is the first of three companion reviews that consider obesity. This review focuses on the genetics, viruses, insulin resistance, inflammation, gut microbiome, and circadian rhythms that promote obesity, along with hormones, growth factors, and organs and tissues that control its development. It shows that the regulation of energy balance (intake vs. expenditure) relies on the interplay of a variety of hormones from adipose tissue, gastrointestinal tract, pancreas, liver, and brain. It details how integrating central neurotransmitters and peripheral metabolic signals (e.g., leptin, insulin, ghrelin, peptide YY_3-36) is essential for controlling energy homeostasis and feeding behavior. It describes the distinct types of adipocytes and how fat cell development is controlled by hormones and growth factors acting via a variety of receptors, including peroxisome proliferator-activated receptor-gamma, retinoid X, insulin, estrogen, androgen, glucocorticoid, thyroid hormone, liver X, constitutive androstane, pregnane X, farnesoid, and aryl hydrocarbon receptors. Finally, it demonstrates that obesity likely has origins in utero. Understanding these biochemical drivers of adiposity and metabolic dysfunction throughout the life cycle lends plausibility and credence to the "obesogen hypothesis" (i.e., the importance of environmental chemicals that disrupt these receptors to promote adiposity or alter metabolism), elucidated more fully in the two companion reviews.

Carving the senescent phenotype by the chemical reactivity of catecholamines: An integrative review

Macromolecules damaged by covalent modifications produced by chemically reactive metabolites accumulate in the slowly renewable components of living bodies and compromise their functions. Among such metabolites, catecholamines (CA) are unique, compared with the ubiquitous oxygen, ROS, glucose and methylglyoxal, in that their high chemical reactivity is confined to a limited set of cell types, including the dopaminergic and noradrenergic neurons and their direct targets, which suffer from CA propensities for autoxidation yielding toxic quinones, and for Pictet-Spengler reactions with carbonyl-containing compounds, which yield mitochondrial toxins. The functions progressively compromised because of that include motor performance, cognition, reward-driven behaviors, emotional tuning, and the neuroendocrine control of reproduction. The phenotypic manifestations of the resulting disorders culminate in such conditions as Parkinson's and Alzheimer's diseases, hypertension, sarcopenia, and menopause. The reasons to suspect that CA play some special role in aging accumulated since early 1970-ies. Published reviews address the role of CA hazardousness in the development of specific aging-associated diseases. The present integrative review explores how the bizarre discrepancy between CA hazardousness and biological importance could have emerged in evolution, how much does the chemical reactivity of CA contribute to the senescent phenotype in mammals, and what can be done with it.

Food preferences and thyroid hormones in children and adolescents with obesity

BACKGROUND

Thyroid hormones profoundly affect energy metabolism but their interrelation with food preference, which might contribute to childhood obesity development, are much less understood. In this study, we investigated if thyroid hormone levels are associated with specific modulation of food preference and potentially linked to the level of obesity in children and adolescents.

METHODS

Interrelations between food preference and peripheral thyroid activity were examined in a population of 99 non-obese and 101 obese children and adolescents (12.8 ± 3.6 years of age, 111/89 F/M) randomly selected from the patients of the Obesity and Metabolic Disease Out-patient Research Unit at National Institute for Children's Diseases in Bratislava in a period between December 2017 and March 2020.

RESULTS

Children and adolescents with obesity had a lower preference for food rich in high sucrose and high-complex carbohydrates, while the preference for protein and fat-containing food and that for dietary fibers did not differ between obese and nonobese. In adolescents with obesity, free thyroxine (FT4) correlated positively with the preference for a high protein and high fat-rich diet, irrespective of the fatty acid unsaturation level. Moreover, FT4 correlated negatively with the preference for dietary fibers, which has been also exclusively found in obese adolescents. Individuals with obesity with higher FT4 levels had higher systemic levels of AST and ALT than the population with lower FT4. Multiple regression analysis with age, sex, BMI-SDS, and FT4 as covariates revealed that FT4 and male gender are the major predictors of variability in the preference for a diet high in protein, fat, and monounsaturated fatty acids. FT4 was the sole predictor of the preference for a diet containing saturated and polyunsaturated fatty acids as well as for a diet low in fiber.

CONCLUSION

The link between free thyroxin levels and dietary preference for food rich in fat and protein is present exclusively in individuals with obesity. Higher serum FT4 was linked with elevated AST and ALT in children and adolescents with obesity, and FT4 was the best predictor for preference for food rich in fat and low in fiber. This may indicate that FT4 could contribute to the development of childhood obesity and its complications by modulating food preference.

THE ROLE OF CIRCADIAN REGULATION OF GHRELIN LEVELS IN PARKINSON’S DISEASE (LITERATURE REVIEW)

The paper is aimed at the analysis of the role of the circadian regulation of ghrelin levels in patients with Parkinson’s disease. Based on the literature data, patients with Parkinson’s disease have clinical fluctuations in the symptoms of the disease, manifested by the diurnal changes in motor activity, autonomic functions, sleep-wake cycle, visual function, and the efficacy of dopaminergic therapy. Biological rhythms are controlled by central and peripheral oscillators which links with dopaminergic neurotransmission – core of the pathogenesis of Parkinson`s disease. Circadian system is altered in Parkinson`s disease due to that ghrelin fluctuations may be changed. Ghrelin is potential food-entrainable oscillator because it is linked with clock genes expression. In Parkinson`s disease this hormone may induce eating behavior changing and as a result metabolic disorder. The “hunger hormone” ghrelin can be a biomarker of the Parkinson’s disease, and the study of its role in the pathogenesis, as well as its dependence on the period of the day, intake of levodopa medications to improve the effectiveness of treatment is promising.