Association between eating behavior, anthropometric and biochemical measurements, and peptide YY (PYY) hormone levels in obese adolescents in outpatient care

Use of Biomarkers in Nutrition Intervention Studies of Children: A Scoping Review

Obesity in youth is an increasingly prevalent public health concern worldwide. Lifestyle interventions aim to help participants establish healthy habits and reduce obesity-related disease risk by targeting physical activity and dietary habits. Most studies assess weight loss, but biomarkers may enable more rapid and comprehensive assessment of intervention success. This scoping review aims to synthesize the published literature on which biomarkers are assessed during interventions for pediatric obesity to inform future use. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A literature search of five databases conducted in February 2022 returned 1579 unique and relevant articles published between 2006 and 2021. After screening titles, abstracts, and full text, four reviewers determined that 43 studies met eligibility requirements. Quality screening was conducted, and 97.7% of papers were of fair or good quality. Of the 43 studies, 47% reported measures of adipose-related signaling molecules inclusive of adipokines, 74% included insulin-related biomarkers, 63% reported lipid-related biomarkers, 40% reported proinflammatory cytokine biomarkers, 12% reported measures of skin and/or plasma carotenoids, 40% measured blood pressure, and 21% included liver enzymes. Sixty-seven percent of studies measured biomarkers in whole blood, 40% measured biomarkers in plasma, 56% measured biomarkers in serum, and 2% measured biomarkers in urine. This work summarizes the current use of biomarkers in lifestyle intervention studies enrolling children. These biomarkers could be clinically relevant for pediatric weight management interventions.

Bone changes post-sleeve gastrectomy in relation to body mass and hormonal changes

OBJECTIVE

To determine mechanisms contributing to impaired bone health in youth 24 months following sleeve gastrectomy (SG).

DESIGN

Twenty-four-month longitudinal observational study.

METHODS

Participants included 23 youth undergoing SG and 30 non-surgical controls (NS) 13-25 years old with moderate-to-severe obesity. Subjects underwent fasting labs for bone turnover markers (N-terminal propeptide of type 1 procollagen, C-telopeptide (CTX)), sex hormones, sex hormone binding globulin (SHBG), and enteric peptides, DXA for areal bone mineral density (aBMD) and body composition, high-resolution peripheral quantitative CT for volumetric BMD (vBMD) at the distal radius and tibia, and microfinite element analysis for strength estimates.

RESULTS

Groups did not differ for mean age or BMI z-scores. Over 24 months, compared to NS, SG had greater reductions in BMI z-scores, and spine, hip, and femoral neck aBMD Z-scores (P ≤ .012), greater increases in serum CTX and SHBG (P ≤ .039), and greater decreases in estrone and ghrelin (P ≤ .021). Among females, estrone and free androgen index (FAI) decreased (P ≤ .022) in SG vs NS groups. After controlling for age and sex, decreases in BMI and lean mass were associated with decreases in total hip and femoral neck aBMD Z-scores, and decreases in radial total and trabecular vBMD and failure load, and tibial total and trabecular vBMD. Among females, after controlling for age, decreases in estrone were associated with decreases in spine aBMD Z-scores and radial total and trabecular vBMD, and decrease in FAI with decreases in radial failure load.

CONCLUSION

Reductions in BMI, lean mass, and sex steroids over 24 months post-SG are associated with bone loss and could be targeted for preventative or therapeutic interventions. Clinical trial registration number: The study is registered in ClinicalTrials.gov (NCT02557438).

Changes in Sex Steroids and Enteric Peptides After Sleeve Gastrectomy in Youth in Relation to Changes in Bone Parameters

CONTEXT

Sleeve gastrectomy (SG) improves metabolic endpoints but is associated with impaired bone outcomes.

OBJECTIVE

To determine mechanisms contributing to impaired bone health in youth following SG.

METHODS

12-month longitudinal observational study in a multidisciplinary tertiary-care hospital, including 64 youth 13-25 years old with moderate-to-severe obesity (51 females); 30 underwent SG and 34 were nonsurgical (NS) controls. SG was undertaken after a combined decision-making process between treatment team and patient. The main outcome measures were fasting blood for enteric peptides, sex steroids, sclerostin, and bone turnover markers (N-terminal propeptide of type 1 procollagen [P1NP] and C-terminal cross-linking telopeptide [CTX]); dual-energy X-ray absorptiometry measures of areal bone mineral density (aBMD) and body composition; high resolution peripheral quantitative computed tomography; measures of volumetric BMD (vBMD); microfinite element analysis of strength estimates (distal radius and tibia).

RESULTS

SG had greater reductions in body mass index (BMI) z-scores, serum estrone, and the free androgen index (FAI) (P ≤ .046), and greater increases in sclerostin, P1NP, and CTX (P ≤ .010) than NS controls. Fasting ghrelin decreased in SG vs NS (P < .0001); fasting peptide YY did not change. Most changes were driven by female SG participants. Among females (the majority of study participants), after controlling for baseline age and race, reductions in total hip aBMD Z-scores were positively associated with changes in BMI, lean mass, estrone, FAI, and ghrelin, and inversely with changes in sclerostin.. Decreases in total vBMD of the radius and tibia were associated positively with decreases in BMI. Increases in CTX were associated with decreases in BMI, lean mass, and ghrelin, and increases in sclerostin.

CONCLUSION

Bone loss after SG in youth is associated with changes in body composition, sex steroids, sclerostin, and enteric peptides. These are potential targets for future preventative or therapeutic strategies.

Gut hormones, adipokines, and pro- and anti-inflammatory cytokines/markers in loss of control eating: A scoping review

Loss of control (LOC) eating is the defining feature of binge-eating disorder, and it has particular relevance for bariatric patients. The biomarkers of LOC eating are unclear; however, gut hormones (i.e., ghrelin, cholecystokinin [CCK], peptide YY [PYY], glucagon-like peptide 1 [GLP-1], and pancreatic polypeptide [PP]), adipokines (i.e., leptin, adiponectin), and pro- and anti-inflammatory cytokines/markers (e.g., high-sensitivity C-reactive protein [hsCRP]) are candidates due to their involvement in the psychophysiological mechanisms of LOC eating. This review aimed to synthesize research that has investigated these biomarkers with LOC eating. Because LOC eating is commonly examined within the context of binge-eating disorder, is sometimes used interchangeably with subclinical binge-eating, and is the latent construct underlying disinhibition, uncontrolled eating, and food addiction, these eating behaviors were included in the search. Only studies among individuals with overweight or obesity were included. Among the identified 31 studies, 2 studies directly examined LOC eating and 4 studies were conducted among bariatric patients. Most studies were case-control in design (n = 16) and comprised female-dominant (n = 13) or female-only (n = 13) samples. Studies generally excluded fasting total ghrelin, fasting CCK, fasting PYY, and fasting PP as correlates of the examined eating behaviors. However, there was evidence that the examined eating behaviors were associated with lower levels of fasting acyl ghrelin (the active form of ghrelin) and adiponectin, higher levels of leptin and hsCRP, and altered responses of postprandial ghrelin, CCK, and PYY. The use of GLP-1 analog was able to decrease binge-eating. In conclusion, this review identified potential biomarkers of LOC eating. Future studies would benefit from a direct focus on LOC eating (especially in the bariatric population), using longitudinal designs, exploring potential mediators and moderators, and increased inclusion of the male population.

Lack of peptide YY signaling in mice disturbs gut microbiome composition in response to high-fat diet

Peptide YY (PYY), produced by endocrine L cells in the gut, is known for its critical role in regulating gastrointestinal functions as well as satiety. However, how these processes are integrated with maintaining a healthy gut microbiome composition is unknown. Here, we show that lack of PYY in mice leads to distinct changes in gut microbiome composition that are diet‐dependent. While under chow diet only slight differences in gut microbiome composition could be observed, high‐fat diet (HFD) aggravated these differences. Specifically an increased abundance of the Bacteroidetes phylum with a corresponding decrease of the Firmicutes/Bacteroidetes ratio could be detected in Pyy‐knockout (KO) mice in response to HFD. Detailed analysis of the Bacteroidetes phylum further revealed that the Alistipes genus belonging to the Rikenellaceae family, the Parabacteroides belonging to the Tannerellaceae family, as well as Muribaculum were increased in Pyy‐KO mice. In order to investigate whether these changes are associated with changed markers of gut barrier and immunity, we analyzed the colonic expression of various pro‐inflammatory cytokines, as well as tight junction proteins and mucin 2, and identified increased mRNA expression of the tight junction proteins Cldn2 and Ocel1 in Pyy‐KO mice, while pro‐inflammatory cytokine expression was not significantly altered. Together these results highlight a critical gene‐environment interaction between diet and the gut microbiome and its impact on homeostasis of the intestinal epithelium under conditions of reduced PYY signaling which is commonly seen under obese conditions.