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Metabolism: Clinical and Experimental Mar 2019Obesity is among the most threatening health burdens worldwide and its prevalence has markedly increased over the last decades. Obesity maybe considered a heritable... (Review)
Review
Obesity is among the most threatening health burdens worldwide and its prevalence has markedly increased over the last decades. Obesity maybe considered a heritable trait. Identifications of rare cases of monogenic obesity unveiled that hypothalamic circuits and the brain-adipose axis play an important role in the regulation of energy homeostasis, appetite, hunger and satiety. For example, mutations in the leptin gene cause obesity through almost unsuppressed overeating. Common (multifactorial) obesity, most likely resulting from a concerted interplay of genetic, epigenetic and environmental factors, is clearly linked to genetic predisposition by multiple risk variants, which, however only account for a minor part of the general BMI variability. Although GWAS opened new avenues in elucidating the complex genetics behind common obesity, understanding the biological mechanisms relative to the specific risk contributing to obesity remains poorly understood. Non-genetic factors such as eating behavior or physical activity strongly modulate the individual risk for developing obesity. These factors may interact with genetic predisposition for obesity through epigenetic mechanisms. Thus, here, we review the current knowledge about monogenic and common (multifactorial) obesity highlighting the important recent advances in our knowledge on how epigenetic regulation is involved in the etiology of obesity.
Topics: Epigenesis, Genetic; Genetic Predisposition to Disease; Humans; Obesity; Precision Medicine
PubMed: 30399374
DOI: 10.1016/j.metabol.2018.10.007 -
Adolescent Medicine: State of the Art... 2017Obesity is a complex, heritable trait influenced by the interplay of genetics, epigenetics, metagenomics and the environment. With the increasing access to high... (Review)
Review
Obesity is a complex, heritable trait influenced by the interplay of genetics, epigenetics, metagenomics and the environment. With the increasing access to high precision diagnostic tools for genetic investigations, numerous genes influencing the phenotype have been identified, especially in early onset severe obesity. This review summarizes the current knowledge on the known genetic causes of obesity and the available therapeutic options. Furthermore, we discuss the role and potential mechanism of epigenetic changes that may be involved as mediators of the environmental influences and that may provide future opportunities for intervention.
Topics: Epigenesis, Genetic; Humans; Obesity
PubMed: 30416642
DOI: No ID Found -
Expert Opinion on Drug Discovery 2015Obesity is a body weight disorder characterized by excess adiposity that increases the risk for developing co-morbidities such as type 2 diabetes. A large medical need... (Review)
Review
INTRODUCTION
Obesity is a body weight disorder characterized by excess adiposity that increases the risk for developing co-morbidities such as type 2 diabetes. A large medical need exists for new anti-obesity treatments capable of promoting 10% or greater weight loss, with minimal side effects.
AREAS COVERED
The authors describe the application of monogenic forms of rare obesity and genome-wide association studies in selecting critical pathways for drug discovery. Furthermore, they review in detail several pathways and pharmacological targets in the central nervous system (e.g., the leptin-melanocortin axis, the opioid system, GLP-1/GLP-1 system, and FGF21/FGFR1c/β-Klotho axis) that play an important role in the regulation of feeding behavior and energy homeostasis. Special focus is given to new strategies that engage well-known targets via novel mechanisms in order to circumvent issues seen with previous drug candidates that failed in the clinic. Finally, the authors discuss the recent developments around fixed-dose combinations, targeted polypharmacology, and non-traditional combinations of drugs and devices.
EXPERT OPINION
The future for new weight-loss approaches to treat obesity looks promising. Current therapies have shown modest effects on weight loss in the general obese population but will have greater impact in smaller homogeneous sub-populations of obese subjects using personalized medicine. Drug combinations that target multiple, complementary pathways have the potential to promote double-digit weight loss in a broader, heterogeneous patient population. Furthermore, the development of advanced subcutaneous delivery technologies has opened up opportunities to develop breakthrough peptide and biologic agents for the treatment of obesity.
Topics: Animals; Anti-Obesity Agents; Drug Design; Drug Therapy, Combination; Humans; Molecular Targeted Therapy; Obesity; Weight Loss
PubMed: 25967138
DOI: 10.1517/17460441.2015.1044966 -
Nature Reviews. Endocrinology Jan 2023Lactation is critical to infant short-term and long-term health and protects mothers from breast cancer, ovarian cancer and type 2 diabetes mellitus. The mammary gland... (Review)
Review
Lactation is critical to infant short-term and long-term health and protects mothers from breast cancer, ovarian cancer and type 2 diabetes mellitus. The mammary gland is a dynamic organ, regulated by the coordinated actions of reproductive and metabolic hormones. These hormones promote gland development from puberty onwards and induce the formation of a branched, epithelial, milk-secreting organ by the end of pregnancy. Progesterone withdrawal following placental delivery initiates lactation, which is maintained by increased pituitary secretion of prolactin and oxytocin, and stimulated by infant suckling. After weaning, local cytokine production and decreased prolactin secretion trigger large-scale mammary cell loss, leading to gland involution. Here, we review advances in the molecular endocrinology of mammary gland development and milk synthesis. We discuss the hormonal functions of the mammary gland, including parathyroid hormone-related peptide secretion that stimulates maternal calcium mobilization for milk synthesis. We also consider the hormonal composition of human milk and its associated effects on infant health and development. Finally, we highlight endocrine and metabolic diseases that cause lactation insufficiency, for example, monogenic disorders of prolactin and prolactin receptor mutations, maternal obesity and diabetes mellitus, interventions during labour and delivery, and exposure to endocrine-disrupting chemicals such as polyfluoroalkyl substances in consumer products and other oestrogenic compounds.
Topics: Female; Humans; Pregnancy; Mammary Glands, Human; Oxytocin; Placenta; Prolactin; Lactation
PubMed: 36192506
DOI: 10.1038/s41574-022-00742-y -
Obesity (Silver Spring, Md.) May 2021There is a genetic component to human obesity that accounts for 40% to 50% of the variability in body weight status but that is lower among normal weight individuals... (Review)
Review
There is a genetic component to human obesity that accounts for 40% to 50% of the variability in body weight status but that is lower among normal weight individuals (about 30%) and substantially higher in the subpopulation of individuals with obesity and severe obesity (about 60%-80%). The appreciation that heritability varies across classes of BMI represents an important advance. After controlling for BMI, ectopic fat and fat distribution traits are characterized by heritability levels ranging from 30% to 55%. Defects in at least 15 genes are the cause of monogenic obesity cases, resulting mostly from deficiencies in the leptin-melanocortin signaling pathway. Approximately two-thirds of the BMI heritability can be imputed to common DNA variants, whereas low-frequency and rare variants explain the remaining fraction. Diminishing allele effect size is observed as the number of obesity-associated variants expands, with most BMI-increasing or -decreasing alleles contributing only a few grams or less to body weight. Obesity-promoting alleles exert minimal effects in normal weight individuals but have larger effects in individuals with a proneness to obesity, suggesting a higher penetrance; however, it is not known whether these larger effect sizes precede obesity or are caused by an obese state. The obesity genetic risk is conditioned by thousands of DNA variants that make genetically based obesity prevention and treatment a major challenge.
Topics: Adolescent; Adult; Child; Child, Preschool; Female; Genetic Predisposition to Disease; Humans; Male; Obesity; Young Adult
PubMed: 33899337
DOI: 10.1002/oby.23116 -
Current Opinion in Endocrinology,... Feb 2021Childhood obesity is escalating globally. Lifestyle and behavioral changes, which are the frequently used interventions in clinical practice, lead to only modest... (Review)
Review
PURPOSE OF REVIEW
Childhood obesity is escalating globally. Lifestyle and behavioral changes, which are the frequently used interventions in clinical practice, lead to only modest improvements in children with established obesity. Bariatric surgery is currently the most effective obesity treatment but has very limited utilization in pediatric obesity and is preferentially used for children with worsening comorbidities. There exists a massive treatment gap for children suffering with obesity especially after the failure of lifestyle modifications. Pharmacotherapy that is an established management tool in adults is very infrequently used in children. Only two medications, Phentermine and Orlistat are approved by the Food and Drug Administration (FDA) for use in adolescent obesity. Herein, we discuss the current landscape and available literature on the use of antiobesity pharmacotherapy in children.
RECENT FINDINGS
There are emerging pediatric data about the efficacy of the many weight loss medications that are FDA approved in adults. Moreover, more clinical trials are underway on the rarer, intractable forms of obesity such as monogenic, syndromic, and hypothalamic obesity.
SUMMARY
Weight loss medications in children, like adults, have variable efficacy and similar side effect profiles. Rigorous research and improved education of providers about weight loss medications may address the huge treatment gap in severe pediatric obesity.
Topics: Anti-Obesity Agents; Child; Humans; Pediatric Obesity; Weight Loss
PubMed: 33186194
DOI: 10.1097/MED.0000000000000587 -
Annales D'endocrinologie Feb 2022Rare genetic forms of obesity are linked to impaired energy balance (i.e., eating behaviour and energy expenditure) involving hypothalamic pathways. More than 60 genes... (Review)
Review
Rare genetic forms of obesity are linked to impaired energy balance (i.e., eating behaviour and energy expenditure) involving hypothalamic pathways. More than 60 genes coding for proteins located in the hypothalamic leptin/melanocortin pathway contribute to the development of these rare forms of obesity. The ambition of the French National Protocol for the Diagnosis and Care (PNDS) of Obesity of Rare Causes was to establish practical recommendations for assessment and management at all ages. This report is available on the website of the French Health Authority (HAS). In addition to severe obesity, patients often display obesity-related comorbidities and neuropsychological/psychiatric disorders. These complex conditions make clinical management particularly challenging. Early diagnosis is critical for the organization of coordinated specialized multidisciplinary care, with mandatory interaction between caregivers, social partners and families. Strategies to prevent aggravation of obesity consist in limiting access to food, establishing a reassuring daily eating environment, and the practice of sustained adapted supervised daily physical activity. The implementation of genetic diagnosis in clinical practice now enables a personalized medicine approach with access to new drug therapies, and improves the analysis of the risk/benefit ratio of bariatric surgery.
Topics: Bariatric Surgery; Energy Metabolism; Humans; Hypothalamus; Leptin; Obesity; Obesity, Morbid
PubMed: 34953778
DOI: 10.1016/j.ando.2021.12.003 -
Life (Basel, Switzerland) Jul 2023Obesity affects approximately 1 in 5 youth globally and increases the risk of complications during adolescence and young adulthood, including type 2 diabetes,... (Review)
Review
Obesity affects approximately 1 in 5 youth globally and increases the risk of complications during adolescence and young adulthood, including type 2 diabetes, dyslipidemia, hypertension, non-alcoholic fatty liver disease, obstructive sleep apnea, and polycystic ovary syndrome. Children and adolescents with obesity frequently experience weight stigma and have an impaired quality of life, which may exacerbate weight gain. Pediatric obesity is typically defined using sex-, age-, and population-specific body mass index percentiles. Once identified, pediatric obesity should always be managed with lifestyle modification. However, adolescents with obesity may also benefit from anti-obesity medications (AOM), several of which have been approved for use in adolescents by the US Food and Drug Administration, including liraglutide, phentermine/topiramate, and semaglutide. For children with specific, rare monogenic obesity disorders, setmelanotide is available and may lead to significant weight loss. Metabolic and bariatric surgery may be used for the management of severe obesity in youth; though highly effective, it is limited to specialized centers and has had relatively low pediatric uptake. In this narrative review using pediatric-focused data from original research, reviews, clinical practice guidelines, governmental agencies, and pharmaceutical companies, we review obesity-related metabolic complications in youth and management strategies, including AOM and bariatric surgery.
PubMed: 37511966
DOI: 10.3390/life13071591 -
Frontiers in Endocrinology 2020The chylomicronemia syndrome is characterized by severe hypertriglyceridemia and fasting chylomicronemia and predisposes affected individuals to acute pancreatitis. When... (Review)
Review
The chylomicronemia syndrome is characterized by severe hypertriglyceridemia and fasting chylomicronemia and predisposes affected individuals to acute pancreatitis. When due to very rare monogenic mutations in the genes encoding the enzyme, lipoprotein lipase, or its regulators, APOC2, APOA5, GPIHBP1, and LMF1, it is referred to as the familial chylomicronemia syndrome. Much more frequently, the chylomicronemia syndrome results from a cluster of minor genetic variants causing polygenic hypertriglyceridemia, which is exacerbated by conditions or medications which increase triglyceride levels beyond the saturation point of triglyceride removal systems. This situation is termed the multifactorial chylomicronemia syndrome. These aggravating factors include common conditions such as uncontrolled diabetes, overweight and obesity, alcohol excess, chronic kidney disease and pregnancy and several medications, including diuretics, non-selective beta blockers, estrogenic compounds, corticosteroids, protease inhibitors, immunosuppressives, antipsychotics, antidepressants, retinoids, L-asparaginase, and propofol. A third uncommon cause of the chylomicronemia syndrome is familial forms of partial lipodystrophy. Development of pancreatitis is the most feared complication of the chylomicronemia syndrome, but the risk of cardiovascular disease as well as non-alcoholic steatohepatitis is also increased. Treatment consists of dietary fat restriction and weight reduction combined with the use of triglyceride lowering medications such as fibrates, omega 3 fatty acids and niacin. Effective management of aggravating factors such as improving diabetes control, discontinuing alcohol and replacing or reducing the dose of medications that raise triglyceride levels is essential. Importantly, many if not most cases of the chylomicronemia syndrome can be prevented by effective identification of polygenic hypertriglyceridemia in people with conditions that increase its likelihood or before starting medications that may increase triglyceride levels. Several new pharmacotherapeutic agents are being tested that are likely to considerably improve treatment of hypertriglyceridemia in people at risk.
Topics: Humans; Hyperlipoproteinemia Type I; Hypertriglyceridemia; Pancreatitis
PubMed: 33193106
DOI: 10.3389/fendo.2020.593931 -
The New England Journal of Medicine Oct 2021encodes the Gα (stimulatory G-protein alpha subunit) protein, which mediates G protein-coupled receptor (GPCR) signaling. mutations cause developmental delay, short...
BACKGROUND
encodes the Gα (stimulatory G-protein alpha subunit) protein, which mediates G protein-coupled receptor (GPCR) signaling. mutations cause developmental delay, short stature, and skeletal abnormalities in a syndrome called Albright's hereditary osteodystrophy. Because of imprinting, mutations on the maternal allele also cause obesity and hormone resistance (pseudohypoparathyroidism).
METHODS
We performed exome sequencing and targeted resequencing in 2548 children who presented with severe obesity, and we unexpectedly identified 22 mutation carriers. We investigated whether the effect of mutations on melanocortin 4 receptor (MC4R) signaling explains the obesity and whether the variable clinical spectrum in patients might be explained by the results of molecular assays.
RESULTS
Almost all mutations impaired MC4R signaling. A total of 6 of 11 patients who were 12 to 18 years of age had reduced growth. In these patients, mutations disrupted growth hormone-releasing hormone receptor signaling, but growth was unaffected in carriers of mutations that did not affect this signaling pathway (mean standard-deviation score for height, -0.90 vs. 0.75, respectively; P = 0.02). Only 1 of 10 patients who reached final height before or during the study had short stature. mutations that impaired thyrotropin receptor signaling were associated with developmental delay and with higher thyrotropin levels (mean [±SD], 8.4±4.7 mIU per liter) than those in 340 severely obese children who did not have mutations (3.9±2.6 mIU per liter; P = 0.004).
CONCLUSIONS
Because pathogenic mutations may manifest with obesity alone, screening of children with severe obesity for deficiency may allow early diagnosis, improving clinical outcomes, and melanocortin agonists may aid in weight loss. mutations that are identified by means of unbiased genetic testing differentially affect GPCR signaling pathways that contribute to clinical heterogeneity. Monogenic diseases are clinically more variable than their classic descriptions suggest. (Funded by Wellcome and others.).
Topics: Adolescent; Body Height; Child; Chromogranins; Female; GTP-Binding Protein alpha Subunits, Gs; Humans; Male; Mutation; Mutation, Missense; Pediatric Obesity; Receptor, Melanocortin, Type 4; Receptors, Thyrotropin; Signal Transduction; Exome Sequencing
PubMed: 34614324
DOI: 10.1056/NEJMoa2103329