We examined whether wake-time movement composition was associated with weight loss maintenance among individuals who experienced clinically meaningful weight loss (> 5% of initial weight) using compos Show more
We examined whether wake-time movement composition was associated with weight loss maintenance among individuals who experienced clinically meaningful weight loss (> 5% of initial weight) using compositional data analysis. This was a secondary analysis from a behavioral weight loss maintenance intervention on weight regain over 12 months following clinically meaningful 3-month weight loss. Body weight was assessed at baseline, after weight loss (3 months), and at end of intervention (15 months). Wake-time behaviors (sedentary time [ST], light physical activity [LPA], and moderate-to-vigorous PA [MVPA]) were assessed at two time points during the maintenance intervention using accelerometry. Compositional data analysis was used to examine associations between wake-time movement composition and weight regain (kg). Among 153 individuals (80.4% female, 69.9% White), wake-time movement composition was related to weight regain (p = 0.001). MVPA was negatively associated with weight regain (p's < 0.05). Reallocating 10 min/day from ST or LPA to MVPA was associated with less weight regain (ST: -0.32 kg [-0.53, -0.12]; LPA: -0.37 kg [-0.59, -0.15]). Individuals who maintained clinically meaningful weight loss and those who did not differed in wake-time movement composition, driven by MVPA (36.1 vs. 24.3 min/day). The composition of wake-time behaviors, specifically MVPA, reduces weight regain after clinically meaningful weight loss in a behavioral weight loss maintenance intervention. ClinicalTrials.gov identifier: NCT01664715. Show less
Long-term parenteral nutrition (PN) administration can lead to PN-associated liver diseases (PNALD). Although multiple risk factors have been identified for PNALD, to date, the roles of bile acids (BA Show more
Long-term parenteral nutrition (PN) administration can lead to PN-associated liver diseases (PNALD). Although multiple risk factors have been identified for PNALD, to date, the roles of bile acids (BAs) and the pathways involved in BA homeostasis in the development and progression of PNALD are still unclear. We have established a mouse PN model with IV infusion of PN solution containing soybean oil-based lipid emulsion (SOLE). Our results showed that PN altered the expression of genes involved in a variety of liver functions at the mRNA levels. PN increased liver gene expression of Cyp7a1 and markedly decreased that of Cyp8b1, Cyp7b1, Bsep, and Shp. CYP7A1 and CYP8B1 are important for synthesizing the total amount of BAs and regulating the hydrophobicity of BAs, respectively. Consistently, both the levels and the percentages of primary BAs as well as total non-12α-OH BAs increased significantly in the serum of PN mice compared with saline controls, whereas liver BA profiles were largely similar. The expression of several key liver-X receptor-α (LXRα) target genes involved in lipid synthesis was also increased in PN mouse livers. Retinoid acid-related orphan receptor-α (RORα) has been shown to induce the expression of Cyp8b1 and Cyp7b1, as well as to suppress LXRα function. Western blot showed significantly reduced nuclear migration of RORα protein in PN mouse livers. This study shows that continuous PN infusion with SOLE in mice leads to dysregulation of BA homeostasis. Alterations of liver RORα signaling in PN mice may be one of the mechanisms implicated in the pathogenesis of PNALD. Show less