Metabolic Effects of Oxytocin McCormack, Shana E; Blevins, James E; Lawson, Elizabeth A
Endocrine reviews,
2020-April, Letnik:
41, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Abstract
There is growing evidence that oxytocin (OXT), a hypothalamic hormone well recognized for its effects in inducing parturition and lactation, has important metabolic effects in both sexes. ...The purpose of this review is to summarize the physiologic effects of OXT on metabolism and to explore its therapeutic potential for metabolic disorders. In model systems, OXT promotes weight loss by decreasing energy intake. Pair-feeding studies suggest that OXT-induced weight loss may also be partly due to increased energy expenditure and/or lipolysis. In humans, OXT appears to modulate both homeostatic and reward-driven food intake, although the observed response depends on nutrient milieu (eg, obese vs. nonobese), clinical characteristics (eg, sex), and experimental paradigm. In animal models, OXT is anabolic to muscle and bone, which is consistent with OXT-induced weight loss occurring primarily via fat loss. In some human observational studies, circulating OXT concentrations are also positively associated with lean mass and bone mineral density. The impact of exogenous OXT on human obesity is the focus of ongoing investigation. Future randomized, placebo-controlled clinical trials in humans should include rigorous, standardized, and detailed assessments of adherence, adverse effects, pharmacokinetics/pharmacodynamics, and efficacy in the diverse populations that may benefit from OXT, in particular those in whom hypothalamic OXT signaling may be abnormal or impaired (eg, individuals with Sim1 deficiency, Prader–Willi syndrome, or craniopharyngioma). Future studies will also have the opportunity to investigate the characteristics of new OXT mimetic peptides and the obligation to consider long-term effects, especially when OXT is given to children and adolescents. (Endocrine Reviews XX: XX – XX, 2020)
Graphical Abstract
Graphical Abstract
Hypothalamic obesity (HO) is a rare and complex disorder that confers substantial morbidity and excess mortality. HO is a unique subtype of obesity characterized by impairment in the key brain ...pathways that regulate energy intake and expenditure, autonomic nervous system function, and peripheral hormonal signalling. HO often occurs in the context of hypothalamic syndrome, a constellation of symptoms that follow from disruption of hypothalamic functions, for example, temperature regulation, sleep-wake circadian control, and energy balance. Genetic forms of HO, including the monogenic obesity syndromes, often impact central leptin-melanocortin pathways. Acquired forms of HO occur as a result of tumours impacting the hypothalamus, such as craniopharyngioma, surgery or radiation to treat those tumours, or other forms of hypothalamic damage, such as brain injury impacting the region. Risk for severe obesity following hypothalamic injury is increased with larger extent of hypothalamic damage or lesions that contain the medial and posterior hypothalamic nuclei that support melanocortin signalling pathways. Structural damage in these hypothalamic nuclei often leads to hyperphagia, central insulin and leptin resistance, decreased sympathetic activity, low energy expenditure, and increased energy storage in adipose tissue, the collective effect of which is rapid weight gain. Individuals with hyperphagia are perpetually hungry. They do not experience fullness at the end of a meal, nor do they feel satiated after meals, leading them to consume larger and more frequent meals. To date, most efforts to treat HO have been disappointing and met with limited, if any, long-term success. However, new treatments based on the distinct pathophysiology of disturbed energy homeostasis in acquired HO may hold promise for the future.
To create reference charts for sitting height to standing height ratio (SitHt/Ht) for children in the US, and to describe the trajectory of SitHt/Ht during puberty.
This was a cross-sectional study ...using data from the 1988-1994 National Health and Nutrition Examination Survey III, a strategic random sample of the US population. Comparison between non-Hispanic White (NHW), non-Hispanic Black (NHB) and Mexican American groups was performed by ANOVA to determine if a single population reference chart could be used. ANOVA was used to compare SitHt/Ht in pre-, early, and late puberty.
NHANES III recorded sitting height and standing height measurements in 9569 children aged 2-18 years of NHW (n = 2715), NHB (n = 3336), and Mexican American (n = 3518) ancestry. NHB children had lower SitHt/Ht than NHW and Mexican American children throughout childhood (P < .001). In both sexes, the SitHt/Ht decreased from prepuberty to early puberty and increased in late puberty. Sex-specific percentile charts of SitHt/Ht vs age were generated for NHB and for NHW and Mexican American youth combined.
SitHt/Ht assessment can detect disproportionate short stature in children with skeletal dysplasia, but age-, sex-, and population-specific reference charts are required to interpret this measurement. NHB children in the US have significantly lower SitHt/Ht than other children, which adds complexity to interpretation. We recommend the use of standardized ancestry-specific reference charts in screening for skeletal dysplasias and have developed such charts in this study.
Mitochondrial DNA (mtDNA) genome integrity is essential for proper mitochondrial respiratory chain function to generate cellular energy. Nuclear genes encode several proteins that function at the ...mtDNA replication fork, including mitochondrial single-stranded DNA-binding protein (SSBP1), which is a tetrameric protein that binds and protects single-stranded mtDNA (ssDNA). Recently, two studies have reported pathogenic variants in SSBP1 associated with hearing loss, optic atrophy, and retinal degeneration. Here, we report a 14-year-old Chinese boy with severe and progressive mitochondrial disease manifestations across the full Pearson, Kearns-Sayre, and Leigh syndromes spectrum, including infantile anemia and bone marrow failure, growth failure, ptosis, ophthalmoplegia, ataxia, severe retinal dystrophy of the rod-cone type, sensorineural hearing loss, chronic kidney disease, multiple endocrine deficiencies, and metabolic strokes. mtDNA genome sequencing identified a single large-scale 5 kilobase mtDNA deletion (m.8629_14068del5440), present at 68% and 16% heteroplasmy in the proband's fibroblast cell line and blood, respectively, suggestive of a mtDNA maintenance defect. On trio whole exome blood sequencing, the proband was found to harbor a novel de novo heterozygous mutation c.79G>A (p.E27K) in SSBP1. Size exclusion chromatography of p.E27K SSBP1 revealed it remains a stable tetramer. However, differential scanning fluorimetry demonstrated p.E27K SSBP1 relative to wild type had modestly decreased thermostability. Functional assays also revealed p.E27K SSBP1 had altered DNA binding. Molecular modeling of SSBP1 tetramers with varying combinations of mutant subunits predicted general changes in surface accessible charges, strength of inter-subunit interactions, and protein dynamics. Overall, the observed changes in protein dynamics and DNA binding behavior suggest that p.E27K SSBP1 can interfere with DNA replication and precipitate the introduction of large-scale mtDNA deletions. Thus, a single large-scale mtDNA deletion (SLSMD) with manifestations across the clinical spectrum of Pearson, Kearns-Sayre, and Leigh syndromes may result from a nuclear gene disorder disrupting mitochondrial DNA replication.
Weight-for-length (WFL) is currently used to assess adiposity under 2 years. We assessed WFL- versus BMI-based estimates of adiposity in healthy infants in determining risk for early obesity.
...Anthropometrics were extracted from electronic medical records for well-child visits for 73 949 full-term infants from a large pediatric network. World Health Organization WFL and BMI z scores (WFL-z and BMI-z, respectively) were calculated up to age 24 months. Correlation analyses assessed the agreement between WFL-z and BMI-z and within-subject tracking over time. Logistic regression determined odds of obesity at 2 years on the basis of adiposity classification at 2 months.
Agreement between WFL-z and BMI-z increased from birth to 6 months and remained high thereafter. BMI-z at 2 months was more consistent with measurements at older ages than WFL-z at 2 months. Infants with high BMI (≥85th percentile) and reference WFL (5th-85th percentiles) at 2 months had greater odds of obesity at 2 years than those with high WFL (≥85th percentile) and reference BMI (5th-85th percentiles; odds ratio, 5.49 vs 1.40; P < .001). At 2 months, BMI had a higher positive predictive value than WFL for obesity at 2 years using cut-points of either the 85th percentile (31% vs 23%) or 97.7th percentile (47% vs 29%).
High BMI in early infancy is more strongly associated with early childhood obesity than high WFL. Forty-seven percent of infants with BMI ≥97.7th percentile at 2 months (versus 29% of infants with WFL ≥97.7th percentile at 2 months) were obese at 2 years. Epidemiologic studies focused on assessing childhood obesity risk should consider using BMI in early infancy.
Prevention of osteoporosis in adulthood begins with optimizing bone health in early life. The longitudinal association between growth and bone accretion during childhood is not fully understood.
To ...assess the acquisition of whole-body (WB) and skeletal site-specific bone mineral content (BMC) relative to linear growth in a healthy, diverse, longitudinal cohort of children, adolescents, and young adults and to test for differences related to sex and African American race.
This investigation was a mixed longitudinal study with annual assessments for up to 7 years at 5 US clinical centers. Participants were healthy children, adolescents, and young adults. The study dates were July 2002 through March 2010. The dates of the analysis were June through December 2016.
Anthropometrics, BMC, and body composition via dual-energy x-ray absorptiometry. The superimposition by translation and rotation (SITAR) analysis method was used to define the mean trajectories for height, WB lean soft tissue, appendicular lean soft tissue, and WB and skeletal site-specific BMC acquisition and to measure the age and magnitude of peak velocity for each parameter. The SITAR modeling was performed separately by sex and self-reported race.
Among 2014 healthy children, adolescents, and young adults (1022 50.7% female and 479 23.8% African American) aged 5 to 19 years at study entry, the mean age of peak height velocity was 13.1 years (95% CI, 13.0-13.2 years) in African American boys vs 13.4 years (95% CI, 13.3-13.4 years) in non-African American boys (difference, -0.3 years; 95% CI, -0.4 to -0.1 years) and 11.0 years (95% CI, 10.8-11.1 years) in African American girls vs 11.6 years (95% CI, 11.5-11.6 years) in non-African American girls (difference, -0.6 years; 95% CI, -0.7 to -0.5 years). Age of peak acquisition of WB BMC was 14.0 years (95% CI, 13.8-14.1 years) in African American boys vs 14.0 years (95% CI, 13.9-14.1 years) in non-African American boys (difference, -0.0 years; 95% CI, -0.2 to 0.2 years) and 12.1 years (95% CI, 12.0-12.3 years) in African American girls vs 12.4 years (95% CI, 12.3-12.5 years) in non-African American girls (difference, -0.3 years; 95% CI, -0.4 to -0.1 years). At age 7 years, children had acquired 69.5% to 74.5% of maximal observed height but only 29.6% to 38.1% of maximal observed WB BMC. Adolescents gained 32.7% to 35.8% of maximal observed WB BMC during the 2 years before and 2 years after peak height velocity. Another 6.9% to 10.7% of maximal observed WB BMC occurred after linear growth had ceased. In the group at highest risk for fracture, non-African American boys, peak fracture incidence occurred approximately 1 year before peak height velocity.
In this longitudinal study, height gains substantially outpaced gains in BMC during childhood, which could contribute to fracture risk. A significant proportion of bone is accrued after adult height is achieved. Therefore, late adolescence represents a potentially underrecognized window of opportunity to optimize bone mass.
The purpose of this statement is to provide consensus-based recommendations for optimal management and care for patients with primary mitochondrial disease. This statement is intended for physicians ...who are engaged in the diagnosis and management of these patients. Working group members were appointed by the Mitochondrial Medicine Society. The panel included members with several different areas of expertise. The panel members utilized surveys and the Delphi method to reach consensus. We anticipate that this statement will need to be updated as the field continues to evolve. Consensus-based recommendations are provided for the routine care and management of patients with primary genetic mitochondrial disease.
•Friedreich’s Ataxia diabetes (FRDA-related DM) was reported in 8.7% of those with FRDA.•Risk factors for FRDA-related DM include age, severe disease, and cardiac disease.•FRDA-related DM is distinct ...from common forms of diabetes.•Currently, insulin and metformin are the most common treatments for FRDA-related DM.•Newer anti-diabetic agents have not been used widely in FRDA-related DM.
Friedreich’s Ataxia (FRDA) is a progressive neuromuscular disorder typically caused by GAA triplet repeat expansions in both frataxin gene alleles. FRDA can be complicated by diabetes mellitus (DM). The objective of this study was to describe the prevalence of, risk factors for, and management practices of FRDA-related DM.
FACOMS, a prospective, multi-site natural history study, includes 1,104 individuals. Extracted data included the presence of DM and other co-morbidities, genetic diagnosis, and markers of disease severity. We performed detailed medical record review and a survey for the subset of individuals with FRDA-related DM followed at one FACOMS site, Children’s Hospital of Philadelphia.
FRDA-related DM was reported by 8.7% of individuals. Age, severe disease, and FRDA cardiac complications were positively associated with DM risk. FRDA-related DM was generally well-controlled, as reflected by HbA1c, though diabetic ketoacidosis did occur. Insulin is the mainstay of treatment (64–74% overall); in adults, metformin use was common and newer glucose-lowering agents were used rarely.
Clinical factors identify individuals at increased risk for FRDA-related DM. Future studies should test strategies for FRDA-related DM screening and management, in particular the potential role for novel glucose-lowering therapies in preventing or delaying FRDA-related cardiac disease.
Introduction
Primary mitochondrial disease is caused by either mitochondrial or nuclear DNA mutations that impact the function of the mitochondrial respiratory chain. Individuals with mitochondrial ...disorders have comorbid conditions that may increase their risk for poor bone health. The objective of this retrospective electronic medical record (EMR) review was to examine risk factors for poor bone health in children and adults with primary mitochondrial disease.
Methods
Eighty individuals with confirmed clinical and genetic diagnoses of primary mitochondrial disease at the Children’s Hospital of Philadelphia (CHOP) were included in this study. Risk factors and bone health outcomes were collected systematically, including: anthropometrics (low BMI), risk-conferring co-morbidities and medications, vitamin D status, nutrition, immobility, fracture history, and, where available, dual energy x-ray absorptiometry (DXA) bone mineral density (BMD) results.
Results
Of patients 73% (
n
= 58) had at least one risk factor and 30% (
n
= 24) had four or more risk factors for poor bone health. The median number of risk factors per participant was 2, with an interquartile interval (IQI 0–4). In the subset of the cohort who were known to have sustained any lifetime fracture (
n
= 11), a total of 16 fractures were reported, six of which were fragility fractures, indicative of a clinically significant decrease in bone strength.
Conclusions
The prevalence of risk factors for poor bone health in primary mitochondrial disease is high. As part of supportive care, practitioners should address modifiable risk factors to optimize bone health, and have a low threshold to evaluate clinical symptoms that could suggest occult fragility fracture.
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