Current and emerging therapies for managing hyperphagia and obesity in Prader-Willi syndrome: A narrative review

Feasibility and acceptability of a culinary nutrition programme for adults with mild-to-moderate intellectual disability: FLIP Food and Lifestyle Information Programme

BACKGROUND

Culinary nutrition education can support improved diet-related health and wellbeing. This pre-post pilot study aimed to assess feasibility and acceptability of an eight-session culinary nutrition programme, the Food and Lifestyle Information Programme (FLIP), for adults with mild-to-moderate intellectual disability. A secondary aim was to evaluate preliminary programme effectiveness.

METHOD

Participants were recruited through a disability service provider. Feasibility measures were: recruitment and retention; implementation; engagement and participation; adverse outcomes; and feasibility of outcome measures. Acceptability was assessed using an interactive process evaluation. Effectiveness measures included cooking frequency, cooking and food skill confidence and diet quality.

RESULTS

Six of eight participants completed the intervention with high attendance and programme engagement. FLIP was well received by participants and support workers. No adverse outcomes occurred. Diet quality was feasible to assess.

CONCLUSIONS

Findings can inform content, delivery and evaluation of future culinary nutrition programmes for adults with mild-to-moderate intellectual disability.

Mothering a Child With Complexity and Rarity: A Narrative Inquiry Exploring Prader-Willi Syndrome

Daily experiences of mothers caring for children with Prader-Willi syndrome (PWS) are largely unknown and unvoiced. Knowledge of PWS has generally focused on pathology of the disorder. This emphasis overlooks the challenging moments of everyday life caring for children with PWS. Storied accounts of mothers caring for children with PWS offer expanded narratives to medicalized descriptions of experience. An understanding of everyday challenges in managing physical and mental health issues of PWS including hyperphagia and anxiety may create shifts in social and clinical perspectives. This understanding could improve practices in health and social care for families with PWS. This narrative inquiry studied everyday experience using storied accounts. Participants were mothers caring for children aged 3-17 years with genetically confirmed PWS who were experiencing hyperphagia. Four participants were recruited, and each interviewed 8-12 times over 12 months. Field texts and narrative accounts were co-composed through a collaborative process of analysis. Engaging with participants' day-to-day experiences offered insights into their work of nurturing, caring, and contributing to the care of a child with PWS. Narrative threads focused on complexity and rarity and include the desire to be normal, how ordinary becomes extraordinary, isolation, behaviors and normative standards, and alternative stories of mothering. Recommendations for practice and policy include (a) challenges of mothering a child with complexity, (b) moving beyond functionality and impairment to participation and quality of life, (c) re-storying narratives and supports for families, and (d) engaging with mothers to determine care priorities.

Prader-Willi syndrome in a large sample from Spain: general features, obesity and regular use of psychotropic medication

BACKGROUND

Prader-Willi syndrome (PWS), a genetically determined disorder, the most frequent cause of early onset obesity, is associated with physical and cognitive dysfunctions and behavioural disturbances; these disturbances are frequently treated with psychotropic medication. The aim of this cross-sectional study was to describe the characteristics of the first large national sample of persons with PWS in Spain and analyse the relationships of those characteristics with key demographic and clinical factors, particularly with obesity and the regular use of psychotropic medication.

METHODS

Participants were recruited among all members of the Spanish Prader-Willi Association who agreed to take part in the study and fulfilled its inclusion criteria. Family and patient demographic features, family size and birth order, intelligence quotient (IQ), anthropometric measures, lifestyle habits, behavioural disturbances (with the Aberrant Behavior Checklist) and clinical data, as well as use of psychotropic drugs and their side effects (with the UKU scale), were collected in genetically confirmed cases of PWS. Bivariate and logistic regression analyses were used for determining the associations of demographic and clinical factors with both obesity and the regular use of psychotropic medication.

RESULTS

The cohort included 177 participants (aged 6-48 years), that is, 90 (50.8%) males and 87 (49.2%) females. Behavioural disturbances were present in a range of 75% to 93% of participants; psychotropic medication was prescribed to 81 (45.8%) of them. Number of siblings showed a direct correlation with IQ, especially among males, and inappropriate speech was more intense in only-child females. Obesity was, in parallel, strongly associated with ascending age and with not being currently under growth hormone (GH) treatment. Participants taking any psychotropic medication were characterised by more frequent age ≥30 years, high level of hyperactivity and a psychiatric diagnosis.

CONCLUSIONS

Characterisation of persons with PWS in Spain confirms their physical and behavioural phenotype and supports the long-term application of GH therapy and the rational use of psychotropic medication.

A genetic condition that spans both extremes of the nutritional spectrum

Prader-Willi syndrome (PWS) is a complex genetic disorder caused by lack of expression of genes on the paternally inherited chromosome 15q11.2-q13 region, known as the Prader Willi critical region. Nutritional clinical manifestations change with age and are described in four different phases. The phases span both extremes of the nutritional spectrum, beginning with an infant with poor sucking reflexes and failure to thrive then progressing to an adolescent who may have hyperphagia and be at risk for obesity. The phenotype is likely due to hypothalamic dysfunction due to genetic changes in the Prader Willi critical region. Researchers are examining the pathological mechanisms that determine the disease course.

The Pivotal Role of Oxytocin's Mechanism of Thermoregulation in Prader-Willi Syndrome, Schaaf-Yang Syndrome, and Autism Spectrum Disorder

Oxytocin (Oxt) regulates thermogenesis, and altered thermoregulation results in Prader-Willi syndrome (PWS), Schaaf-Yang syndrome (SYS), and Autism spectrum disorder (ASD). PWS is a genetic disorder caused by the deletion of the paternal allele of 15q11-q13, the maternal uniparental disomy of chromosome 15, or defects in the imprinting center of chromosome 15. PWS is characterized by hyperphagia, obesity, low skeletal muscle tone, and autism spectrum disorder (ASD). Oxt also increases muscle tonicity and decreases proteolysis while PWS infants are hypotonic and require assisted feeding in early infancy. This evidence inspired us to merge the results of almost 20 years of studies and formulate a new hypothesis according to which the disruption of Oxt's mechanism of thermoregulation manifests in PWS, SYS, and ASD through thermosensory abnormalities and skeletal muscle tone. This review will integrate the current literature with new updates on PWS, SYS, and ASD and the recent discoveries on Oxt's regulation of thermogenesis to advance the knowledge on these diseases.

Effect of non-pharmacological intervention on the nutritional status of patients with Prader Willi Syndrome

INTRODUCTION

Obesity is highly prevalent in patients with Prader-Willi syndrome (PWS), particularly among adults. This condition, which can be morbid in many cases, is multifactorial and has a complex management. The purpose of our study was to describe the feasibility of achieving a better nutritional status, including normal weight in individuals diagnosed with PWS, through specific nutritional interventions within the framework of a transdisciplinary treatment and without resorting to pharmacological treatments or growth hormone (GH).

METHODOLOGY

This observational study included patients with confirmed genetic diagnosis of PWS, receiving transdisciplinary treatment in a specialized rare diseases institution. Patients under treatment with GH and those under pharmacological treatment with nutritional objectives were excluded from the study. All patients attended our institution regularly on a weekly or fortnightly basis. Anthropometric records, including weight, height, and body mass index (BMI) were evaluated in each visit from treatment onset until the last check-up.

RESULTS

We included 24 patients with confirmed genetic diagnosis of PWS. At baseline, 9 patients (38 %) had obesity grade III, 1 (4 %) of obesity grade II, 10 (42 %) of obesity grade I, 2 (8 %) of overweight, and 2 patients (8 %) with normal baseline weight. After a median duration of 52 months (interquartile range 23-116 months) of transdisciplinary nutritional treatment, we identified a significant reduction in BMI (baseline 40.2 ± 15.7 kg/m2 vs. follow-up 28.3 ± 6.7 kg/m2, p < 0.0001), without significant differences regarding height (baseline 1.45 ± 0.1 m vs. follow-up 1.48 ± 0.1 m, p = 0.09).

CONCLUSION

In this study, we demonstrated that nutritional nonpharmacologic interventions immersed in a transdisciplinary treatment enabled a consistent and sustainable improvement in BMI and nutritional status among patients with PWS.

Effect of semaglutide on weight loss and glycaemic control in patients with Prader-Willi Syndrome and type 2 diabetes

Prader-Willi Syndrome (PWS) is the most common genetic cause of obesity, occurring in approximately 1 in 15,000 newborns. It results from the lack of expression of genes on the paternal allele of the chromosomal region 15q-11q13 (65-75% due to type 1 or type 2 deletion). Individuals with PWS experience associated symptoms such as hypotonia, hyperphagia, and early-onset obesity (before 5 years of age). Around 20% of adults with PWS also develop type 2 diabetes. Previous studies have shown the beneficial effects of GLP1-RA medications, such as exenatide and liraglutide, in treating type 2 diabetes in PWS. However, there is limited information available on the use of semaglutide in PWS. This study aimed to evaluate the effects of semaglutide on weight loss and glycaemic control in four patients with PWS and type 2 diabetes associated with obesity. The patients were started on weekly subcutaneous progressive doses of semaglutide.

Evaluating the effect of recombinant human growth hormone treatment on sleep-related breathing disorders in toddlers with Prader-Willi syndrome: a one-year retrospective cohort study

BACKGROUND

Recombinant human growth hormone (rhGH) therapy is beneficial for children with Prader-Willi syndrome (PWS) in improving short stature and metabolism, but the effect of early rhGH treatment on respiratory and sleep parameters for PWS children under three years old remains elusive. Thus, this study aimed to investigate the impact of rhGH treatment on sleep-related breathing disorders (SRBDs) for toddlers with PWS.

METHODS

A total of 17 age-matched PWS patients receiving rhGH treatment (rhGH group) and 17 control individuals not receiving rhGH treatment (non-rhGH group) were recruited for this study between October 2018 and January 2023. Data related to polysomnography-polygraphy (PSG) and serum levels of insulin-like growth factor (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) were collected.

RESULTS

The mean age in the rhGH group was 20.76 ± 9.22 months, which was comparable to that of the non-rhGH group (25.23 ± 13.81 months). The demographic and anthropometric parameters were similar across the two groups after 52 weeks of treatment. Administration of rhGH to toddlers did not exert adverse effects on the obstructive apnea-hypopnea index (OAHI), central apnea index (CAI), oxygen desaturation index (ODI), mean percutaneous oxygen saturation (SpO2), lowest SpO2, duration when SpO2 is lower than 90%, or proportion of the patients with SpO2 lower than 90%. Furthermore, the increased IGF-1 z-score and IGFBP-3 level did not worsen SRBDs.

CONCLUSION

Treatment with rhGH for 52 weeks on young toddlers with PWS showed no deleterious effects on SRBDs. This shed more light on the importance of initiating rhGH therapy early in PWS patients.

"Unable to Feed My Hungry Child": Experiences of Mothers Caring for Children With Prader-Willi Syndrome

Mothers' experiences of caring for children with Prader-Willi Syndrome (PWS) is largely unknown. With no treatment for PWS, parents undertake (extra)ordinary care practices to keep children safe from overeating and self harm. Knowledge of these care practices could lead to effective interventions. Narrative inquiry was used to study everyday experience with Canadian mothers. Participants cared for a child 3 to 17 years old who had hyperphagia. Participants were interviewed 8 to 12 times each over the course of a year. Narrative accounts were co-composed through a collaborative process of analysis. Engaging with participants' everyday experiences amplified complex care needs for families and gaps in health and social care systems. Narrative threads focused on engaging in (extra)ordinary care practices, rigid care work to keep children healthy and safe, tension from others while enacting these care practices, and difficulty conforming to social expectations with childrearing and care work. Recommendations for practice and policy include (a) shifting from untenable care practices, (b) reconceptualizing care work, and (c) alternative care models.

The link between obesity and insulin resistance among children: Effects of key metabolites

BACKGROUND

Childhood obesity became a severe public health challenge, and insulin resistance (IR) was one of the common complications. Both obesity and IR were considered as the basis of metabolic disorders. However, it is unclear which common key metabolites are associated with childhood obesity and IR.

METHODS

The children were divided into normal weight and overweight/obese groups. Fasting blood glucose and fasting insulin were measured, and homeostasis model assessment of insulin resistance was calculated. Liquid chromatography-tandem mass spectrometry was applied for metabonomic analysis. Multiple linear regression analysis and correlation analysis explored the relationships between obesity, IR, and metabolites. Random forests were used to rank the importance of differential metabolites, and relative operating characteristic curves were used for prediction.

RESULTS

A total of 88 normal-weight children and 171 obese/overweight children participated in the study. There was a significant difference between the two groups in 30 metabolites. Childhood obesity was significantly associated with 10 amino acid metabolites and 20 fatty acid metabolites. There were 12 metabolites significantly correlated with IR. The ranking of metabolites in random forest showed that glutamine, tyrosine, and alanine were important in amino acids, and pyruvic-ox-2, ethylmalonic-2, and phenyllactic-2 were important in fatty acids. The area under the curve of body mass index standard deviation  score (BMI-SDS) combined with key amino acid metabolites and fatty acid metabolites for predicting IR was 80.0% and 76.6%, respectively.

CONCLUSIONS

There are common key metabolites related to IR and obese children, and these key metabolites combined with BMI-SDS could effectively predict the risk of IR.

A Personalized Approach to Determining the Caloric Needs of Children with Prader-Willi Syndrome Treated with Growth Hormone

Prader-Willi Syndrome (PWS) is the most frequent cause of genetic obesity. Early reports indicate that children with PWS require 20-40% fewer calories than healthy children to maintain adequate growth. Growth hormone treatment for children with PWS, approved in 2000, affects the body composition and probably affects energy requirements. This retrospective cross-sectional study analyzed the caloric intake in children with PWS aged from 6 months to 12 years old who underwent growth hormone treatment, comparing the patients' caloric intake calculated from parent-recorded dietary intake versus the recommended caloric intake for healthy children, taking into account the age, sex, height, weight, and physical activity. We analyzed the data from 25 patients (13 (52%) boys; mean age, 6.72 ± 2.81 y; median age at starting growth hormone treatment, 1.4 y (IQR: 0.78-2.29); 17 (68%) normal weight and 8 (32%) overweight or obese). The mean daily energy intake was 1208 ± 186 kcal/d, representing 96.83% ± 18.66 of the recommended caloric intake for healthy children. The caloric intake in children with PWS treated with growth hormone was very similar to that recommended for healthy children; thus, we should rethink the dietary recommendations for these children.

Interference effect of food and emotional stimuli in Stroop-like tasks for children and adults with Prader-Willi Syndrome

Interference effect of food and emotional stimuli in Stroop-like tasks for children and adults with Prader-Willi Syndrome. The aim of this work was to study the way items related to food or emotion are processed by a population known to have difficulties with dietary restriction, namely individuals with Prader-Willi Syndrome (PWS). Given the presence of intellectual disability (ID) in PWS, our experiments were designed to examine whether these difficulties were specific to PWS or linked with their ID. Two modified Stroop tasks (i.e., a food version and an emotional version) were administered to seventy-four children (aged between 6 and 16 years old) divided into three groups (one with PWS, one with ID matched on age and Intellectual Quotient (IQ), and one healthy group matched on age) and to eighty-four adults (aged between 18 and 48 years old) distributed in the same three groups. For both tasks, a picture version was used for the children and a word version for the adults. For the food Stroop task, (Experiment 1), materials were composed of low or high-caloric food items and stimuli not related to food. The results show a food Stroop effect for children and adults with PWS that was absent in the group of healthy participants. Moreover, a food Stroop effect was also significant for adults with ID. For the emotional Stroop task (Experiment 2), materials were composed of negative, positive and neutral stimuli. The emotional Stroop effect was also obtained for children and adults with PWS as well as for the healthy group, but not for the age- and IQ-matched group. For the PWS groups, results show a preservation to process positive pictures for children and difficulties to process negative stimuli for both age-groups. These results suggest that people with PWS have difficulties in disengaging their attention when food stimuli are present in their environment and poorer abilities to process negative ones. These difficulties endure in adulthood.

Novel therapeutics in rare genetic obesities: A narrative review

The better understanding of the molecular causes of rare genetic obesities and its associated phenotype involving the hypothalamus allows today to consider innovative therapeutics focused on hunger control. Several new pharmacological molecules benefit patients with monogenic or syndromic obesity. They are likely to be among the treatment options for these patients in the coming years, helping clinicians and patients prevent rapid weight progression and eventually limit bariatric surgery procedures, which is less effective in these patients. Their positioning in the management of such patients will be needed to be well defined to develop precision medicine in genetic forms of obesity.

The Diagnosis and Genetic Mechanisms of Prader-Willi Syndrome: Findings From a Moroccan Population Study

Background Prader-Willi syndrome (PWS) is a complex genetic disorder caused by a deficit in gene expression on the paternal inherited chromosome 15q11.2-q13. It affects various aspects of growth and development, including feeding, cognitive function, and behavior. Early diagnosis and management of PWS can significantly improve outcomes for patients and their families. Methods In this study, we analyzed a group of 29 clinically diagnosed patients suspected of PWS. All patients were referred to the medical genetics and onco-genetics service for genetic consultation and molecular analysis. We used DNA methylation analysis and fluorescence in situ hybridization (FISH) to confirm the diagnosis and identify the underlying genetic mechanisms. Results Our analysis showed that five out of seven patients (71.43%) with a positive methylation-specific PCR (MSP) had chromosomal deletion by FISH and presented major clinical signs summarized by morbid obesity in 65.21% of cases and neonatal hypotonia in 42.85% of cases. This finding indicates that paternal 15q11-q13 deletion is the most common genetic mechanism involved in PWS. Conclusion The results of this study highlight the importance of early diagnosis and molecular analysis in the management of Prader-Willi syndrome. Our findings contribute to a better understanding of the genotype-phenotype correlation in the Moroccan population and provide families with a rigorous molecular diagnosis, relevant genetic counseling, and multidisciplinary support. Further research is needed to explore the underlying mechanisms of PWS and develop effective interventions to improve outcomes for affected individuals.

The efficacy of intranasal oxytocin in patients with Prader-Willi syndrome: A systematic review and meta-analysis

BACKGROUND AND AIMS

Prader-Willi Syndrome (PWS) is a rare genetic disease. Oxytocin is a neuropeptide hormone that impacts fear, and social recognition. Intranasal administration of oxytocin can be utilized to treat PWS patients. The results of published trials assessing the effects of intranasal oxytocin in PWS are variable. The current systematic review aims to investigate the efficacy of oxytocin in Prader-Willi patients.

METHODS

We conducted a systematic literature search on Pubmed, Web of Science, and Scopus from inception to March 2022 for relevant interventional randomized controlled trials (RCTs) reporting the effect of oxytocin in patients with Prader-Willi syndrome. We assessed the quality of included trials using the Cochrane tool risk of bias 1. We performed the meta-analysis with Revman software version 5.4. In addition, we visualized our results using forest plots. We assessed the heterogeneity by using the Chi-square test.

RESULTS

Relevant to hyperphagia, the data extracted in three studies comprising 92 patients did not show positive outcomes of oxytocin compared to placebo (MD = 0.18; 95% CI: -0.44, 0.80; P = 0.56). Three studies that included 94 patients revealed no significant effects regarding weight between oxytocin and placebo (MD = 0.30; 95% CI: -0.22, 0.83; P = 0.25). The Aberrant Behaviour Checklist found that group-administered oxytocin improved behaviour compared to their counterpart who received a placebo.

CONCLUSION

Oxytocin didn't have significant effects on hyperphagia or weight. To establish the impact of oxytocin in Prader-Willi patients, additional prospective, large-sample randomized controlled trials (RCTs) are needed to avoid controversy.

Efficacy of Liraglutide in Obesity in Children and Adolescents: Systematic Review and Meta-Analysis of Randomized Controlled Trials

In the past few decades, childhood obesity has become a significant global health issue, impacting around 107.7 million children and adolescents globally. There is currently minimal usage of pharmacological therapies for childhood obesity in the pediatric population. This research assessed the efficacy of liraglutide in treating childhood and adolescent obesity. Until 20 October 2022, a systematic literature review was done utilizing PubMed, Scopus, Web of Science, and Embase databases. The search phrases "liraglutide", "pediatric obesity", "children", and "adolescents" were utilized. Using the search method, a total of 185 articles were found. Three studies demonstrating liraglutide's effectiveness in treating child and adolescent obesity were included. The selected research was done in the United States. As an intervention, liraglutide was administered to 296 participants at a maximal dosage of 3.0 mg. All examined trials were in phase 3. This comprehensive analysis revealed no clinically significant differences between liraglutide and body weight (kg; MD -2.62; 95%CI -6.35 to 1.12; p = 0.17) and body mass index (kg/m²; MD -0.80; 95%CI -2.33 to 0.73, p = 0.31). There was no evidence that liraglutide increased hypoglycemia episodes (RR 1.08; 95%CI 0.37 to 3.15; p = 0.79), or side consequences. However, it was shown that the medicine might help reduce BMI and weight combined with a healthy diet and regular exercise. A lifestyle change may have favorable consequences that will be assessed in the future for adjunctive therapy. PROSPERO database (CRD42022347472).

Clinical Trials in Prader-Willi Syndrome: A Review

Prader-Willi syndrome (PWS) is a complex, genetic, neurodevelopmental disorder. PWS has three molecular genetic classes. The most common defect is due to a paternal 15q11-q13 deletion observed in about 60% of individuals. This is followed by maternal disomy 15 (both 15 s from the mother), found in approximately 35% of cases. the remaining individuals have a defect of the imprinting center that controls the activity of imprinted genes on chromosome 15. Mild cognitive impairment and behavior problems in PWS include self-injury, anxiety, compulsions, and outbursts in childhood, impacted by genetic subtypes. Food seeking and hyperphagia can lead to morbid obesity and contribute to diabetes and cardiovascular or orthopedic problems. The control of hyperphagia and improving food-related behaviors are the most important unmet needs in PWS and could be addressed with the development of a new therapeutic agent, as currently no approved therapeutics exist for PWS treatment. The status of clinical trials with existing results for the management of obesity and hyperphagia in PWS will be discussed in this review, including treatments such as beloranib, setmelanotide, a diazoxide choline controlled-release tablet (DCCR), an unacylated ghrelin analogue, oxytocin and related compounds, glucagon-like peptide 1 receptor agonists, surgical intervention, and transcranial direct-current stimulation.

Prader-Willi Syndrome in Adults: An Update On Nutritional Treatment and Pharmacological Approach

PURPOSE OF REVIEW

Prader-Willi syndrome (PWS) is a rare and complex genetic disorder with multiple effects on the metabolic, endocrine, and neurological systems, as well as behavioral and intellectual difficulties. Despite advances in understanding the genetic basis of obesity in PWS, there are conflicting data on its management. Therefore, the present manuscript aims to provide an update on the nutritional treatment and pharmacological approach in adult patients with PWS.

RECENT FINDINGS

The management of obesity in patients with PWS is challenging and requires the cooperation of an experienced multidisciplinary team, including the nutritionist. An adequate clinical evaluation including nutritional and biochemical parameters should be performed to tailor the best therapeutic strategy. Both lifestyle and pharmacological interventions may represent useful strategies to prevent the high rate of morbidity and mortality related to PWS. The use of bariatric surgery is still controversial. Although it is imperative to adopt an obesity prevention strategy in childhood, there is promising evidence for the treatment of obesity in adulthood with current obesity medications in conjunction with lifestyle interventions.

Dysregulated adipose tissue expansion and impaired adipogenesis in Prader-Willi syndrome children before obesity-onset

OBJECTIVE

Prader-Willi syndrome (PWS) is a rare genetic imprinting disorder resulting from the expression loss of genes on the paternally inherited chromosome 15q11-13. Early-onset life-thriving obesity and hyperphagia represent the clinical hallmarks of PWS. The noncoding RNA gene SNORD116 within the minimal PWS genetic lesion plays a critical role in the pathogenesis of the syndrome. Despite advancements in understanding the genetic basis for PWS, the pathophysiology of obesity development in PWS remains largely uncharacterized. Here, we aimed to investigate the signatures of adipose tissue development and expansion pathways and associated adipose biology in PWS children without obesity-onset at an early stage, mainly from the perspective of the adipogenesis process, and further elucidate the underlying molecular mechanisms.

METHODS

We collected inguinal (subcutaneous) white adipose tissues (ingWATs) from phase 1 PWS and healthy children with normal weight aged from 6 M to 2 Y. Adipose morphology and histological characteristics were assessed. Primary adipose stromal vascular fractions (SVFs) were isolated, cultured in vitro, and used to determine the capacity and function of white and beige adipogenic differentiation. High-throughput RNA-sequencing (RNA-seq) was performed in adipose-derived mesenchymal stem cells (AdMSCs) to analyze transcriptome signatures in PWS subjects. Transient repression of SNORD116 was conducted to evaluate its functional relevance in adipogenesis. The changes in alternative pre-mRNA splicing were investigated in PWS and SNORD116 deficient cells.

RESULTS

In phase 1 PWS children, impaired white adipose tissue (WAT) development and unusual fat expansion occurred long before obesity onset, which was characterized by the massive enlargement of adipocytes accompanied by increased apoptosis. White and beige adipogenesis programs were impaired and differentiated adipocyte functions were disturbed in PWS-derived SVFs, despite increased proliferation capacity, which were consistent with the results of RNA-seq analysis of PWS AdMSCs. We also experimentally validated disrupted beige adipogenesis in adipocytes with transient SNORD116 downregulation. The transcript and protein levels of PPARγ, the adipogenesis master regulator, were significantly lower in PWS than in control AdMSCs as well as in SNORD116 deficient AdMSCs/adipocytes than in scramble (Scr) cells, resulting in the inhibited adipogenic program. Additionally, through RNA-seq, we observed aberrant transcriptome-wide alterations in alternative RNA splicing patterns in PWS cells mediated by SNORD116 loss and specifically identified a changed PRDM16 gene splicing profile in vitro.

CONCLUSIONS

Imbalance in the WAT expansion pathway and developmental disruption are primary defects in PWS displaying aberrant adipocyte hypertrophy and impaired adipogenesis process, in which SNORD116 deficiency plays a part. Our findings suggest that dysregulated adiposity specificity existing at an early phase is a potential pathological mechanism exacerbating hyperphagic obesity onset in PWS. This mechanistic evidence on adipose biology in young PWS patients expands knowledge regarding the pathogenesis of PWS obesity and may aid in developing a new therapeutic strategy targeting disturbed adipogenesis and driving AT plasticity to combat abnormal adiposity and associated metabolic disorders for PWS patients.

Social consequences and genetics for the child with overweight and obesity: An obesity medicine association (OMA) clinical practice statement 2022

Background

This Obesity Medicine Association (OMA) clinical practice statement (CPS) covers two topics: 1) genetics and 2) social consequences for the child with overweight and obesity. This CPS is intended to provide clinicians with an overview of clinical practices applicable to children and adolescents with body mass indices greater than or equal to the 85th percentile for their ages, particularly those with adverse consequences resulting from increased body mass. The information in this CPS is based on scientific evidence, supported by the medical literature, and derived from the clinical experiences of members of the OMA.

Methods

The scientific information and clinical guidance in this CPS is based upon referenced evidence and derived from the clinical perspectives of the authors.

Results

This OMA clinical practice statement details two topics: 1) genetics and 2) social consequences for the child with overweight and obesity.

Conclusions

This OMA clinical practice statement on genetics and social consequences for the child with overweight and obesity is an overview of current literature. The literature provides a roadmap to the improvement of the health of children and adolescents with obesity, especially those with metabolic, physiological, and psychological complications.

A Review of Prader–Willi Syndrome

Prader–Willi Syndrome (PWS, OMIM #176270) is a rare complex genetic disorder due to the loss of expression of paternally derived genes in the PWS critical region on chromosome 15q11-q13. It affects multiple neuroendocrine systems and may present failure to thrive in infancy, but then, hyperphagia and morbid obesity starting in early childhood became the hallmark of this condition. Short stature, hypogonadism, sleep abnormalities, intellectual disability, and behavioral disturbances highlight the main features of this syndrome. There have been a significant number of advances in our understanding of the genetic mechanisms underlying the disease, especially discoveries of MAGEL2, NDN, MKRN3, and SNORD116 genes in the pathophysiology of PWS. However, early diagnosis and difficulty in treating some of the disease’s most disabling features remain challenging. As our understanding of PWS continues to grow, so does the availability of new therapies and management strategies available to clinicians and families.

The Efficacy, Safety, and Pharmacology of a Ghrelin O-Acyltransferase Inhibitor for the Treatment of Prader-Willi Syndrome

CONTEXT

Acylated ghrelin (AG) stimulates appetite and is elevated compared to its unacylated (UAG) counterpart in Prader-Willi syndrome (PWS). GLWL-01 is a selective, reversible inhibitor of ghrelin O-acyltransferase (GOAT), the enzyme that converts UAG into AG.

OBJECTIVE

This work aimed to assess the efficacy, pharmacokinetics, pharmacodynamics, and safety of GLWL-01 in the treatment of PWS patients.

METHODS

A double-blind, placebo-controlled, phase 2 crossover study was conducted with 2 active treatment periods of 28 days in 19 patients (aged 16-65 years; body mass index (BMI) ≥ 28) with genetically confirmed PWS. The study took place in 7 hospital-based study centers in the United States and Canada. Patients received placebo or GLWL-01 (450 mg twice daily) orally after lead-in placebo and washout periods. The Hyperphagia Questionnaire for Clinical Trials and Caregiver Global Impression of Change were used to measure reductions in hyperphagia. Plasma concentrations of AG and UAG were evaluated as correlates.

RESULTS

Treatment resulted in statistically significant differences compared to placebo in plasma AG (P = .0002), UAG (P = .0488), and AG/UAG (P = .0003). GLWL-01 did not statistically significantly reduce hyperphagia-related behavior or bring about changes in global clinical end points, as assessed by caregivers. Anthropometric and clinical parameters correlated with obesity did not statistically significantly change in response to treatment. Less than half of patients reported a treatment-emergent adverse event (TEAE). No deaths, serious adverse events, or severe TEAEs were reported.

CONCLUSION

GLWL-01 is safe and well tolerated. Pharmacological parameters confirmed the inhibition of GOAT following administration of GLWL-01. Patients' eating behaviors, BMI, blood glucose, and total cholesterol, among other similar measures, were not modified.

Prader–Willi Syndrome: Possibilities of Weight Gain Prevention and Treatment

Prader–Willi syndrome (PWS) is a complex genetic disorder which involves the endocrine and neurologic systems, metabolism, and behavior. The aim of this paper is to summarize current knowledge on dietary management and treatment of PWS and, in particular, to prevent excessive weight gain. Growth hormone (GH) therapy is the recommended standard treatment for PWS children, because it improves body composition (by changing the proportion of body fat and lean body mass specifically by increasing muscle mass and energy expenditure), linear growth, and in infants, it promotes psychomotor and IQ development. In early childhood, the predominant symptom is hyperphagia which can lead to early onset, severe obesity with different obesity-related comorbidities. There are several studies on anti-obesity medications (metformin, topiramate, liraglutide, setmelanotide). However, these are still limited, and no widely accepted consensus guideline exists concerning these drugs in children with PWS. Until there is a specific treatment for hyperphagia and weight gain, weight must be controlled with the help of diet and exercise. Below the age of one year, children with PWS have no desire to eat and will often fail to thrive, despite adequate calories. After the age of two years, weight begins to increase without a change in calorie intake. Appetite increases later, gradually, and becomes insatiable. Managing the progression of different nutritional phases (0–4) is really important and can delay the early onset of severe obesity. Multidisciplinary approaches are crucial in the diagnosis and lifelong follow-up, which will determine the quality of life of these patients.

Patients with Prader-Willi Syndrome (PWS) Underwent Bariatric Surgery Benefit more from High-Intensity Home Care

BACKGROUND

Long-term weight loss effect of bariatric surgeries for patients with Prader-Willi Syndrome (PWS) remains controversial since factors like postoperative home care intensity may impact the outcome. The aim of this study was to evaluate the role of home care intensity on long-term weight loss effect of bariatric surgery in patients with PWS.

METHODS

This was a prospective observational study on patients with PWS undergoing bariatric surgery and patients were enrolled from July 2015 to December 2016. Detailed information of patients' weight and behaviors was recorded by caregivers postoperatively. The intensities of home care applied to patients were classified into four categories (high, moderate, low, and very low) according to the records.

RESULTS

Six cases (3 males, 3 females) were enrolled in this study with LSG (n = 2), RYGB (n = 3), and LSG-DJB (n = 1) as their primary operation. The mean BMI of these participants was 46.78 ± 11.63 kg/m², and the mean age was 17.66 ± 6.59 years. All patients had at least 5 years of follow-ups, and the %EWL were 51.57 ± 23.36%, 64.54 ± 18.97%, 35.34 ± 36.53%, 19.45 ± 41.78%, and - 4.74 ± 71.50% in the half, first, second, third, and fifth year after surgery respectively. Two patients with high-intensity home care achieved a %EWL of 70.57 ± 8.86% in the fifth year after surgery.

CONCLUSIONS

Overall long-term weight loss of bariatric surgery for patients with PWS was not found through the follow-ups. Two patients with high-intensity home care maintained weight loss at the fifth-year follow-up, suggesting a pivotal role of high-intensity home care in long-term outcomes of bariatric surgery in patients with PWS.

The effects of glucagon-like peptide (GLP)-1 receptor agonists on weight and glycaemic control in Prader-Willi syndrome: A systematic review

OBJECTIVE

The mainstay management of hyperphagia and obesity in Prader-Willi syndrome (PWS) relies on dietary restrictions, strict supervision and behavioural modifications, which can be stressful for the patient and caregiver. There is no established pharmacological strategy to manage this aspect of PWS. Theoretically, glucagon-like peptide-1 (GLP-1) receptor agonists (GLP1-RA) used in patients with obesity and type 2 diabetes mellitus (T2DM) may be efficacious in weight and glycaemic control of PWS patients. We conducted a systematic review of the literature to summarize the evidence on the use of GLP1-RA in PWS patients.

DESIGN

Primary studies were searched in major databases using key concepts 'Prader-Willi syndrome' and 'GLP1 receptor agonist' and outcomes, 'weight control OR glycaemic control OR appetite regulation'.

RESULTS

Ten studies included, summarizing GLP1-RA use in 23 PWS patients (age, 13-37 years), who had used either exenatide (n = 14) or liraglutide (n = 9) over a duration of 14 weeks to 4 years. Sixteen (70%) of these patients had T2DM. Ten patients experienced improvement in body mass index, ranging from 1.5 to 16.0 kg/m² , while improvement in HbA1c was seen in 19 of 23 cases, ranging between 0.3% and 7.5%. All five studies reporting appetite or satiety showed improvement in satiety levels. There were no reported serious side effects.

CONCLUSIONS

GLP1-RA appears safe in PWS patients and may have potential benefits for weight, glycaemic and appetite control. Nonetheless, we also highlight a significant gap in the literature on the lack of well-designed studies in this area, which limits the recommendation of GLP1-RA use in PWS patients at present.

Genetic conditions of short stature: A review of three classic examples

Noonan, Turner, and Prader-Willi syndromes are classical genetic disorders that are marked by short stature. Each disorder has been recognized for several decades and is backed by extensive published literature describing its features, genetic origins, and optimal treatment strategies. These disorders are accompanied by a multitude of comorbidities, including cardiovascular issues, endocrinopathies, and infertility. Diagnostic delays, syndrome-associated comorbidities, and inefficient communication among the members of a patient's health care team can affect a patient's well-being from birth through adulthood. Insufficient information is available to help patients and their multidisciplinary team of providers transition from pediatric to adult health care systems. The aim of this review is to summarize the clinical features and genetics associated with each syndrome, describe best practices for diagnosis and treatment, and emphasize the importance of multidisciplinary teams and appropriate care plans for the pediatric to adult health care transition.

Circulating Irisin in Children and Adolescents With Prader-Willi Syndrome: Relation With Glucose Metabolism

Irisin is a myokine involved in the browning of white adipose tissue and regulation of energy expenditure, glucose homeostasis and insulin sensitivity. Debated evidence exists on the metabolic role played by irisin in children with overweight or obesity, while few information exist in children with Prader Willi Syndrome (PWS), a condition genetically prone to obesity. Here we assessed serum irisin in relation to the metabolic profile and body composition in children and adolescents with and without PWS. In 25 PWS subjects [age 6.6-17.8y; body mass index standard deviation score (BMI SDS) 2.5 ± 0.3] and 25 age, and BMI-matched controls (age 6.8-18.0y; BMI SDS, 2.8 ± 0.1) we assessed irisin levels and metabolic profile inclusive of oral glucose tolerance test (OGTT), and body composition by dual-energy X-ray absorptiometry (DXA). In PWS, we recorded lower levels of fat-free mass (FFM) (p <0.05), fasting (p<0.0001) and 2h post-OGTT insulin (p<0.05) and lower insulin resistance as expressed by homeostatic model of insulin resistance (HOMA-IR) (p<0.0001). Irisin levels were significantly lower in PWS group than in controls with common obesity (p<0.05). In univariate correlation analysis, positive associations linked irisin to insulin OGTT₀ (p<0.05), insulin OGTT₁₂₀ (p<0.005), HOMA-IR (p<0.05) and fasting C-peptide (p<0.05). In stepwise multivariable regression analysis, irisin levels were independently predicted by insulin OGTT₁₂₀. These results suggest a link between irisin levels and insulin sensitivity in two divergent models of obesity.

Health Problems in Individuals With PWS Are Associated With Lower Quality of Life for Their Parents: A Snapshot in the Brazilian Population

Prader-Willi syndrome (PWS) is a complex genetic disorder requiring interdisciplinary team monitoring and intensive care by parents. So far there is little information on people with PWS in Brazil. Our aim was to describe health problems and treatments used by people with PWS in Brazil and their relationship to their parents' quality of life. Parents answered questionnaires about their child's medical and exercise history, behavior problems, sociodemographic characteristics, and their own quality of life. Results: The responses of the participants showed similar health problems as in other countries. Anxiety and tantrums were the behavioral problems most commonly cited by parents. Parents of people with PWS had lower scores in respect of quality of life than the Brazilian population. Behavioral problems in individuals with PWS were negatively associated with their parents' quality of life. Behavioral and medical conditions in the children were associated with reduced quality of life in the parents. We conclude that heath care should not only be directed toward those with PWS, but also their parents.

Targeting the Gut Microbiome in Prader-Willi Syndrome

Overwhelming evidence demonstrates an important role of the gut microbiome in the development of a wide range of diseases, including obesity, metabolic disorders, and mental health symptoms. Indeed, interventions targeting the gut microbiome are being actively investigated as a therapeutic strategy to tackle these diseases. Given that obesity and mental health symptoms are both hallmarks of Prader-Willi syndrome, targeting the gut microbiome may be a promising therapeutical strategy. Only a few studies have investigated the gut microbiome in the context of Prader-Willi syndrome and assessed the efficacy of probiotic supplementation as a therapeutic strategy for this disease. Here, we review the knowledge obtained to this date regarding the gut microbiome in individuals with Prader-Willi syndrome. The limited evidence available indicate that probiotic supplementation improves some metabolic and mental health aspects, however further studies are warranted to determine whether targeting the gut microbiome may constitute a safe and efficient strategy to treat individuals with Prader-Willi syndrome.

Anti-Obesity Medication Use in Children and Adolescents with Prader-Willi Syndrome: Case Review and Literature Search

(1) Background: children with Prader-Willi syndrome (PWS) have high obesity rates due to hyperphagia and decreased metabolic rates. Although anti-obesity medications (AOMs) are prescribed to this population, there are no consensus guidelines on acceptability, safety, and efficacy. We present literature review and case series on AOMs in youth with PWS. (2) Methods: we performed PubMed review from January 2000 to April 2021 utilizing keywords: "Prader-Willi syndrome" or "PWS" and "medication" including: topiramate, metformin, phentermine, liraglutide, orlistat, oxytocin, semaglutide, naltrexone-bupropion. For our case series, patients were identified through retrospective chart reviews from a multi-disciplinary PWS clinic. Eligibility criteria: age ≤ 18 years, genetically confirmed PWS, AOM use for at least 16 weeks, and recent anthropometric data. (3) Results: a literature search yielded 14 articles (3 topiramate, 1 metformin, 4 liraglutide, 5 oxytocin, 1 naltrexone-bupropion). All studies reported improved hyperphagia with variable BMI effects. Ten adolescents met case series eligibility (mean age 13.2 ± 2.6 years, 40% female; AOMs: 6 metformin, 5 topiramate, 2 semaglutide, 3 liraglutide). After AOM course, 60% had decreased or stable BMI z-score. No significant side effects. (4) Conclusions: results suggest AOMs may be useful for weight management in youth with PWS. Additional studies are required to validate findings and support AOM treatment guidelines.

Measuring Meaningful Benefit-Risk Tradeoffs to Promote Patient-Focused Drug Development in Prader-Willi Syndrome: A Discrete-Choice Experiment

Background. Prader-Willi syndrome (PWS) is a rare neurodevelopmental disorder causing quality of life impairments such as insatiable hunger (hyperphagia) and obesity. We explored caregivers’ willingness to assume treatment risk in exchange for reduced hyperphagia according to a PWS-validated observer-reported outcome measure. Methods. We partnered with PWS patient organizations to develop a discrete-choice experiment exploring caregivers’ benefit-risk tradeoffs for emerging PWS treatments. The treatment benefit was a reduction in hyperphagia (as measured by a 0-, 5-, or 10-point change on the Hyperphagia Questionnaire for Clinical Trials [HQ-CT]). Treatment risks included weight gain (none, 5%, 10%), added risk of skin rash (none, 10%, 20%), and risk of liver damage (none, 1 in 1000, 10 in 1000). Preference models were estimated using mixed logistic regression and maximum acceptable risk. We explored differences in preferences across familial caregivers of patients with and without hyperphagia. Results. Four hundred sixty-eight caregivers completed the online survey. The majority of caregivers reported that patients experienced hyperphagia (68%) and half of patients experienced obesity (52%). Caregivers of patients without hyperphagia were willing to accept greater weight gain (16.4% v. 8.1%, P = 0.004) and a higher risk of skin rash (11.7% v. 6.2% P = 0.008) as compared to caregivers of patients with hyperphagia. Caregivers of patients with hyperphagia would accept a higher risk of liver damage as compared to caregivers of patients without hyperphagia (11.9 out of 1000 v. 6.4 out of 1000, P = 0.04). Conclusions. This research demonstrates that caregivers are willing to accept risk in exchange for a five-point improvement on the HQ-CT, a smaller marginal improvement than had been previously classified as meaningful. Patient experience with hyperphagia is a modifier in how much risk caregivers will accept.

Associations Between Hyperphagia, Symptoms of Sleep Breathing Disorder, Behaviour Difficulties and Caregiver Well-Being in Prader-Willi Syndrome: A Preliminary Study

Prader-Willi syndrome (PWS) is a rare genetic disorder characterised by neurodevelopmental delays, hyperphagia, difficulties with social communication and challenging behaviours. Individuals require intensive supervision from caregivers which may negatively affect caregiver quality of life. This study used data collected in the Australasian PWS Registry (n = 50, mean age 11.2 years) to evaluate associations between child behaviours and caregiver mental well-being. Symptoms of sleep-related breathing disorder, child depression and social difficulties were associated with poorer caregiver mental and physical well-being. Growth hormone therapy use was associated with better caregiver mental and physical well-being. Optimising management of problematic behaviours and sleep disturbances have the potential to support caregivers who are the most vital network of support for individuals affected by PWS.

Quantifying the Burden of Hyperphagia in Prader-Willi Syndrome Using Quality-Adjusted Life-years

BACKGROUND

Prader-Willi syndrome (PWS) is a rare disease associated with cognitive impairment, hypotonia, hyperphagia (an insatiable hunger), and obesity. Therapies that target hyperphagia are in development, but understanding the value of these therapies to inform patient-focused drug development (PFDD) requires valid data on disease burden. We estimated disease burden by measuring and comparing quality-adjusted life-years (QALYs) for 3 PWS health states relevant to current PFDD initiatives.

METHODS

Time trade-off (TTO) and a visual analog scale (VAS) were used to elicit PWS caregivers' values for 3 fixed health states for a standardized patient described with (1) untreated PWS, (2) PWS with controlled obesity, and (3) PWS with controlled obesity and hyperphagia. We excluded participants who left at least 1 TTO or VAS question blank or incomplete (noncompleters) and respondents who reported the same answer for all TTO scenarios (nontraders). The remaining group of respondents (traders) were used for all primary analyses. We assessed validity and bias of QALY estimates by comparing differences in health state valuations, treatment priorities, and characteristics among respondents who did and did not complete the TTO.

RESULTS

A total of 458 respondents completed the survey, including 226 traders, 93 nontraders, and 139 noncompleters. Traders valued untreated PWS at 0.69 QALYs, PWS with controlled obesity at 0.79 QALYs, and controlled hyperphagia/obesity at 0.91 QALY (P < 0.01 for differences among health state values). Reported VAS ratings were similar for traders versus nontraders for untreated PWS (38.64 vs 38.95, P = 0.89) and PWS with controlled obesity (57.36 vs 55.14, P = 0.35) but varied for PWS with controlled obesity and hyperphagia (70.70 vs 64.46, P = 0.02). Exclusion of noncompleters did not introduce obvious bias because traders and noncompleters were similar in treatment priorities and characteristics. The exclusion of nontraders did not meaningfully alter mean or distribution of valuations.

CONCLUSIONS

This study found that avoiding hyperphagia decreases the burden of PWS and that these results are robust, even once imposing strict inclusion criteria. Use of fixed health states to estimate QALYs addresses many of the complexities of measuring disease burden in rare and pediatric conditions, indicating the potential value of this approach to inform premarket decision makers in identifying outcome importance. (Clin Ther. 2021;XX:XXX-XXX) © 2021 Elsevier HS Journals, Inc.

Behavioral features in Prader-Willi syndrome (PWS): consensus paper from the International PWS Clinical Trial Consortium

Prader-Willi syndrome (PWS) is a rare neurodevelopmental genetic disorder associated with a characteristic behavioral phenotype that includes severe hyperphagia and a variety of other behavioral challenges such as temper outbursts and anxiety. These behaviors have a significant and dramatic impact on the daily functioning and quality of life for the person with PWS and their families. To date, effective therapies addressing these behavioral challenges have proven elusive, but several potential treatments are on the horizon. However, a limiting factor for treatment studies in PWS is the lack of consensus in the field regarding how to best define and measure the complex and interrelated behavioral features of this syndrome. The International PWS Clinical Trials Consortium (PWS-CTC, www.pwsctc.org) includes expert PWS scientists, clinicians, and patient advocacy organization representatives focused on facilitating clinical trials in this rare disease. To address the above gap in the field, members of the PWS-CTC “Behavior Outcomes Working Group” sought to develop a unified understanding of the key behavioral features in PWS and build a consensus regarding their definition and description. The primary focus of this paper is to present consensus definitions and descriptions of key phenotypic PWS behaviors including hyperphagia, temper outbursts, anxiety, obsessive–compulsive behaviors, rigidity, and social cognition deficits. Patient vignettes are provided to illustrate the interrelatedness and impact of these behaviors. We also review some available assessment tools as well as new instruments in development which may be useful in measuring these behavioral features in PWS.

A Comprehensive Review of Genetically Engineered Mouse Models for Prader-Willi Syndrome Research

Prader-Willi syndrome (PWS) is a neurogenetic multifactorial disorder caused by the deletion or inactivation of paternally imprinted genes on human chromosome 15q11-q13. The affected homologous locus is on mouse chromosome 7C. The positional conservation and organization of genes including the imprinting pattern between mice and men implies similar physiological functions of this locus. Therefore, considerable efforts to recreate the pathogenesis of PWS have been accomplished in mouse models. We provide a summary of different mouse models that were generated for the analysis of PWS and discuss their impact on our current understanding of corresponding genes, their putative functions and the pathogenesis of PWS. Murine models of PWS unveiled the contribution of each affected gene to this multi-facetted disease, and also enabled the establishment of the minimal critical genomic region (PWScr) responsible for core symptoms, highlighting the importance of non-protein coding genes in the PWS locus. Although the underlying disease-causing mechanisms of PWS remain widely unresolved and existing mouse models do not fully capture the entire spectrum of the human PWS disorder, continuous improvements of genetically engineered mouse models have proven to be very powerful and valuable tools in PWS research.

Long-Term Efficacy and Safety of Anti-Obesity Treatment: Where Do We Stand?

PURPOSE OF REVIEW

As a chronic and relapsing disease, obesity impairs metabolism and causes cardiovascular diseases. Although behavioral modification is important for the treatment of obesity, it is difficult to achieve an ideal weight or sustain the process of long-term weight loss. Therefore, the obesity control guidelines strongly recommend lifestyle interventions along with medical treatment for patients who are overweight. There is sufficient evidence supporting that pharmacotherapy in combination with behavior-based interventions can result in significant weight loss and improved cardiometabolism.

RECENT FINDINGS

Recent meta-analyses of new anti-obesity drugs and their weight-loss efficacy have shown that the overall placebo-subtracted weight reduction (%) for at least 12 months ranged from 2.9 to 6.8% for the following drugs: phentermine/topiramate (6.8%), liraglutide (5.4%), naltrexone/bupropion (4.0%), orlistat (2.9%), and lorcaserin (3.1%). However, very recently, on February 13, 2020, the US Food and Drug Administration (FDA) ordered the withdrawal of lorcaserin from markets, as a clinical trial to assess drug safety showed an increased risk of cancer. Currently, the anti-obesity medications that have been approved by the FDA for chronic weight management are orlistat, phentermine/topiramate, naltrexone/bupropion, and liraglutide. However, they are costly and may have adverse effects in some individuals. Therefore, drug therapy should be initiated in obese individuals after weighing its benefits and risks. One of the strategies for long-term obesity control is that anti-obesity medications should be tailored for specific patients depending on their chronic conditions, comorbidities, and preferences.

The regulation of gastric ghrelin secretion

Ghrelin is a gastric hormone with multiple physiological functions, including the stimulation of food intake and adiposity. It is well established that circulating ghrelin levels are closely associated with feeding patterns, rising strongly before a meal and lowering upon food intake. However, the mechanisms underlying the modulation of ghrelin secretion are not fully understood. The purpose of this review is to discuss current knowledge on the circadian oscillation of circulating ghrelin levels, the neural mechanisms stimulating fasting ghrelin levels and peripheral mechanisms modulating postprandial ghrelin levels. Furthermore, the therapeutic potential of targeting the ghrelin pathway is discussed in the context of the treatment of various metabolic disorders, including obesity, type 2 diabetes, diabetic gastroparesis and Prader-Willi syndrome. Moreover, eating disorders including anorexia nervosa, bulimia nervosa and binge-eating disorder are also discussed.

Effects of Bifidobacterium animalis Subsp. lactis (BPL1) Supplementation in Children and Adolescents with Prader-Willi Syndrome: A Randomized Crossover Trial

Prader-Willi syndrome (PWS) is a rare genetic disorder characterized by a wide range of clinical manifestations, including obesity, hyperphagia, and behavioral problems. Bifidobacterium animalis subsp. lactis strain BPL1 has been shown to improve central adiposity in adults with simple obesity. To evaluate BPL1's effects in children with PWS, we performed a randomized crossover trial among 39 patients (mean age 10.4 years). Participants were randomized to placebo-BPL1 (n = 19) or BPL1-placebo (n = 20) sequences and underwent a 12-week period with placebo/BPL1 treatments, a 12-week washout period, and a 12-week period with the crossover treatment. Thirty-five subjects completed the study. The main outcome was changes in adiposity, measured by dual-energy X-ray absorptiometry. Secondary outcomes included lipid and glucose metabolism, hyperphagia, and mental health symptoms. Generalized linear modeling was applied to assess differences between treatments. While BPL1 did not modify total fat mass compared to placebo, BPL1 decreased abdominal adiposity in a subgroup of patients older than 4.5 years (n = 28). BPL1 improved fasting insulin concentration and insulin sensitivity. Furthermore, we observed modest improvements in some mental health symptoms. A follow-up trial with a longer treatment period is warranted to determine whether BPL1 supplementation can provide a long-term therapeutic approach for children with PWS (ClinicalTrials.gov NCT03548480).

Dietary Management for Adolescents with Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a complex, multisystem neurodevelopmental disorder affecting approximately 1 in 25,000 live births. PWS is caused by absence of expression of paternally inherited imprinted genes on chromosome 15q11-q13. The syndrome typically occurs due to one of three genetic mechanisms: paternal deletion of involved genes, maternal uniparental disomy, or imprinting center defects. These genetic anomalies lead to well-described clinical phenotype that includes hypotonia, hypothalamic dysfunction, social and behavioral issues, life-threatening hyperphagia, and elevated probability of obesity. Adolescents with PWS are at the highest risk for development of life-threatening obesity due to increased access to food, decreased physical activity, and hyperphagia. Currently, the only treatment for the hyperphagia is environmental control, including locked kitchens and continuous supervision of the affected individual. Caloric intake must be restricted to prevent obesity, which subsequently increases the hunger drive even more. Research and clinical practice have demonstrated that increasing physical activity along with insuring a well-balanced, nutritionally dense diet can improve overall weight control in adolescents with PWS.