Publications by authors named "Justin R Ryder"

We hypothesized that an increase in nonexercise physical activity (NEPA), assessed by daily steps outside of steps accrued during supervised exercise training sessions, would be positively correlated with the change in VO. Females ages 18-45 yr (n = 44; 30 ± 7 yr; 67.7 ± 18.

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Objective: Weight regain following bariatric surgery remains a clinical challenge, with limited understanding of contributing environmental factors. Per- and polyfluoroalkyl substances (PFAS), persistent chemicals linked to metabolic dysfunction, may influence long-term weight trajectories. This study aimed to evaluate associations between PFAS exposure and changes in BMI, percent weight loss, and waist circumference among adolescents after bariatric surgery.

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Childhood obesity affects nearly one in five children in the U.S. and is a key driver in youth-onset type 2 diabetes (T2D) development and progression.

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The progression of metabolic dysfunction-associated steatotic liver disease (MASLD) to metabolic dysfunction-associated steatohepatitis (MASH) involves alterations in both liver-autonomous and systemic metabolism that influence the liver's balance of fat accretion and disposal. Here, we quantify the contributions of hepatic oxidative pathways to liver injury in MASLD-MASH. Using NMR spectroscopy, UHPLC-MS, and GC-MS, we performed stable isotope tracing and formal flux modeling to quantify hepatic oxidative fluxes in humans across the spectrum of MASLD-MASH, and in mouse models of impaired ketogenesis.

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Objective: The long-term durability of improvements in functional mobility and musculoskeletal pain for adolescents after metabolic and bariatric surgery (MBS) is unknown.

Methods: We used the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study to determine the change in mobility and pain among adolescents who underwent MBS. From standardized 400-m walk tests, we analyzed walk time, heart rate (HR) parameters, and musculoskeletal pain.

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Background: Residential programs have been utilized for the treatment of adolescents with severe obesity, yet few have been evaluated.

Objective: The objectives were to (1) evaluate the effect of a long-term residential treatment program focused on treating adolescent girls with obesity and (2) explore girls' perceptions of weight management during and after participating in the program.

Methods: A mixed-methods approach was used to examine changes in weight outcomes over time among adolescent girls who completed the program ( = 12), and conduct qualitative interviews to explore perceptions of weight management after completion ( = 5).

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Persistent organic pollutants (POPs) are lipophilic environmental contaminants accumulated in the adipose tissue. Weight loss interventions, such as bariatric surgery, can mobilize POPs from adipose tissue into the bloodstream. We hypothesized that this mobilization could contribute to increases in blood pressure among 57 adolescents with severe obesity undergoing bariatric surgery.

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Importance: Vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) are the most commonly performed metabolic and bariatric surgery (MBS) procedures in adolescents and adults. Despite their safety and effectiveness, there is concern over postoperative gastrointestinal symptoms (GIS), especially gastroesophageal reflux symptoms (GERS), in those undergoing VSG.

Objective: To evaluate the long-term prevalence of GIS in adolescents who underwent RYGB or VSG.

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The progression of metabolic-dysfunction-associated steatotic liver disease (MASLD) to metabolic-dysfunction-associated steatohepatitis (MASH) involves complex alterations in both liver-autonomous and systemic metabolism that influence the liver's balance of fat accretion and disposal. Here, we quantify the relative contribution of hepatic oxidative pathways to liver injury in MASLD-MASH. Using NMR spectroscopy, UHPLC-MS, and GC-MS, we performed stable-isotope tracing and formal flux modeling to quantify hepatic oxidative fluxes in humans across the spectrum of MASLD-MASH, and in mouse models of impaired ketogenesis.

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Article Synopsis
  • * MBS has been shown to improve various obesity-related health issues, and this study specifically highlights its positive effects on liver health, including reduced liver enzymes, less fat in the liver, and decreased fibrosis in adolescents with severe obesity.
  • * While many liver-related improvements were noted after MBS, including the potential for complete resolution of certain liver conditions, fibrosis did not fully resolve within the first 12 months, indicating a need for further research and long-term monitoring of liver health post-s
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Background: While endogenous sex hormones (e.g., testosterone, estradiol) are important factors regulating adipose tissue distribution, studies evaluating such relationships in youth across a wide weight status spectrum are limited.

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Article Synopsis
  • PFAS are synthetic chemicals that persist in the environment and can negatively impact human health, and microRNAs can serve as biomarkers for understanding their effects.
  • This study aimed to explore the relationship between PFAS levels and miRNA alterations in children using data from two cohorts in the U.S. and Greece.
  • Findings showed that PFAS exposure was linked to changes in numerous miRNAs, particularly decreased levels of miR-148b-3p and miR-29a-3p, which may be associated with chronic diseases like cardiovascular issues and cancer.
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Importance: Adolescent severe obesity is usually not effectively treated with traditional lifestyle modification therapy. Meal replacement therapy (MRT) shows short-term efficacy for body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) reduction in adolescents, and financial incentives (FIs) may be an appropriate adjunct intervention to enhance long-term efficacy.

Objective: To evaluate the effect of MRT plus FIs vs MRT alone on BMI, body fat, and cardiometabolic risk factors in adolescents with severe obesity.

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Objective: Dichlorodiphenyldichloroethylene (DDE), an obesogen accumulating in adipose tissue, is released into circulation with weight loss, although its impact is underexplored among adolescents. We tested the association using an integrative translational approach of epidemiological analysis among adolescents with obesity and in vitro measures exploring the impact of DDE on adipogenesis via preadipocytes.

Methods: We included 63 participants from the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) cohort.

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Article Synopsis
  • Nonalcoholic fatty liver disease (NAFLD) is a prevalent chronic liver condition among children and adolescents, with varying severity levels, including nonalcoholic steatohepatitis (NASH) which features inflammation and fibrosis.
  • Researchers investigated the link between plasma microRNA (miRNA) levels and various histological features of NAFLD in adolescents, analyzing samples from 81 affected individuals and 54 healthy controls.
  • The study found significant associations between specific upregulated and downregulated miRNAs and features of NAFLD, suggesting that certain miRNAs may play a role in the disease's pathology and could serve as potential biomarkers for NAFLD severity.
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Background: Severe obesity is a complex, chronic disease affecting nearly 9% of adolescents in the U.S. Although the current mainstay of treatment is lifestyle therapy, pediatric clinical practice guidelines recommend the addition of adjunct anti-obesity medication (AOM), such as phentermine and topiramate.

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Background: Roux-en-Y gastric bypass (RYGB) among adolescents with obesity results in significant weight loss; however, depot-specific changes have been understudied.

Objective: We hypothesized that visceral adipose tissue (VAT) reduction in adolescents undergoing RYGB would be greater than other depots and associated with improvement in cardiometabolic risk factors.

Setting: Three specialized treatment centers in Sweden.

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Background Microparticles and endothelial microparticles (EMPs) are implicated in accelerating cardiovascular disease (CVD); however, data in pediatrics are limited. We examined the relationship of microparticles and EMPs with adiposity and subclinical CVD risk measures in a pediatric population to determine their potential as biomarkers of CVD risk. Methods and Results A cross-sectional study of youth (n=280; ages 8-20 years) with a range of body mass index categories was used.

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Background: Meal replacement therapy (MRT) is a structured treatment that is effective for short-term weight reduction in adolescents with severe obesity. However, like other interventions, MRT response is variable.

Objective: The goal of the current study was to characterize the experience of adolescents with severe obesity participating in MRT.

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Acute lymphoblastic leukemia, a heterogenous malignancy characterized by uncontrolled proliferation of lymphoid progenitors and generally initiated in utero, is the most common pediatric cancer. Although incidence of ALL has been steadily increasing in recent decades, no clear reason for this trend has been identified. Rising concurrently with ALL incidence, increasing maternal obesity rates may be partially contributing to increasing ALL prevelance.

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Measurements of liver volume from MR images can be valuable for both clinical and research applications. Automated methods using convolutional neural networks have been used successfully for this using a variety of different MR image types as input. In this work, we sought to determine which types of magnetic resonance images give the best performance when used to train convolutional neural networks for liver segmentation and volumetry.

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