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bioRxiv2026

NEURAL CORRELATES OF SUBJECTIVE FOOD VALUATION IN THE CONTEXT OF BARIATRIC SURGERY

Objective: To examine changes in the neural valuation of high- versus low-calorie stimuli following bariatric surgery and determine whether these changes relate to weight loss at 24 months. Methods: Adults undergoing bariatric surgery completed fMRI scans before surgery and at 4, 12 and 24 months post-surgery while performing the Becker-DeGroot-Marschak auction task to assess willingness-to-pay (WTP) for food stimuli. Linear mixed-effect models tested longitudinal changes in WTP-related blood oxygen level-dependent (BOLD) associations and their interactions with total weight loss at 24 months. Results: WTP for high-calorie foods decreased significantly after surgery, whereas valuation of low-calorie foods remained stable. At 4 months, WTP-BOLD associations for high- versus low-calorie stimuli were enhanced within the frontoparietal control network and right lateral orbitofrontal cortex relative to pre-surgery. These early postoperative changes did not correlate with 24-month weight loss. Instead, greater 24-month weight loss correlated with both pre-surgical and long-term changes (24 months versus pre-surgery) in WTP-BOLD associations within the precuneus, inferior parietal cortex and visual cortex. Conclusion: Bariatric surgery induces early reductions in the valuation of high-calorie foods, potentially through enhanced cognitive control and aversive processing. However, long-term weight-loss success appears more strongly related to trait-like neural differences in self-referential and attentional processing.

neuroscience↗

bioRxiv2022

Increased adipose tissue indices of androgen catabolism and aromatization in women with metabolic dysfunction

BackgroundBody fat distribution is a risk factor for obesity-associated comorbidities, and adipose tissue dysfunction plays a role in this association. In humans, there is a sex difference in body fat distribution, and steroid hormones are known to regulate several cellular processes within adipose tissue. Our aim was to investigate if intra-adipose steroid concentration and expression or activity of steroidogenic enzymes were associated with features of adipose tissue dysfunction in individuals with severe obesity. MethodsSamples from 40 bariatric candidates (31 women, 9 men) were included in the study. Visceral (VAT) and subcutaneous adipose tissue (SAT) were collected during surgery. Adipose tissue morphology was measured by a combination of histological staining and semi-automated quantification. Following extraction, intra-adipose and plasma steroid concentrations were determined by liquid chromatography, electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Aromatase activity was estimated using product-over-substrate ratio, while AKR1C2 activity was measured directly by fluorogenic probe. Gene expression was measured by quantitative PCR. ResultsVAT aromatase activity was positively associated with VAT adipocyte hypertrophy (p-valueadj < 0.01) and negatively with plasma HDL-cholesterol (p-valueadj < 0.01), while SAT aromatase activity predicted dyslipidemia in women even after adjustment for waist circumference, age and hormonal contraceptive use. We additionally compared women with high and low visceral adiposity index (VAI) and found that VAT excess is characterized by adipose tissue dysfunction, increased androgen catabolism mirrored by increased AKR1C2 activity and higher aromatase expression and activity indices. ConclusionIn women, increased androgen catabolism or aromatization is associated with visceral adiposity and adipose tissue dysfunction. DISCLOSURE SUMMARYAT obtained consulting fees form Bausch Health, Novo Nordisk and research funding from Johnson & Johnson Medical Companies as well as Medtronic and GI Windows for studies unrelated to this manuscript. The other authors have nothing to disclose.

physiology↗