Abstract 3728: Extracellular vesicle dynamics in alternate-day fasting combined with low-carbohydrate weight loss intervention
Authors: Faiza Kalam, Kalpana Deepa Dorayappan, Rand T. Akasheh, Zhipeng Tao, Ting-Yuan David Cheng, Krista Varady, Selvendiran Karuppaiyah
Journal: Cancer Research (2025)

Abstract Background: Obesity is associated with systemic metabolic dysregulation and chronic inflammation, which are reflected in alterations in extracellular vesicles (EVs) that mediate intercellular communication. EVs, marked by CD9 and CD63, may also play a critical role in cancer risk by mediating pro-inflammatory and metabolic signaling. This study investigates how an alternate-day fasting and low-carbohydrate (ADF-LC) intervention impact EV secretion and subpopulation dynamics, exploring their potential as candidates for further protein-level investigations to delineate functional roles in inflammation and metabolic dysfunction. Methods: Serum samples were analyzed from 10 participants with obesity enrolled in a 24-week ADF-LC intervention, comprising of a 12-week weight loss phase and a 12-week weight maintenance phase. EVs were isolated from serum collected at baseline (Week 0), after weight loss (Week 12), and after weight maintenance (Week 24). EV quantification and characterization were performed using ImageStream flow cytometry, focusing on EV surface markers CD9 and CD63. Fluorescent antibody labeling was used to detect these tetraspanins, allowing precise measurement of EV subpopulations. Total EV concentrations and subpopulation dynamics were assessed, while protein cargo consistency was evaluated to identify functional shifts. Results: Body weight significantly decreased during the weight loss period (-5.5 ± 0.5%; p &amp;lt; 0.001) and stabilized during the weight maintenance phase (p = 0.57). Net weight loss by Week 24 was -6.3 ± 1.0%, accompanied by a significant reduction in fat mass (p &amp;lt; 0.01). Total EV concentrations significantly declined from baseline to Week 24 (p &amp;lt; 0.05), with notable reductions in CD9+ EV populations at Weeks 12 and 24 (p &amp;lt; 0.05) and CD63+ EV populations at Week 24 (p &amp;lt; 0.05). Despite these changes, EV protein cargo remained consistent, suggesting shifts in specific EV populations and EV-mediated signaling rather than alterations in total protein load. These findings support the need for further investigation into protein changes within EVs to better understand their functional roles in inflammation and metabolic dysfunction. Conclusions: This study highlights significant changes in EV dynamics and subpopulations during ADF-LC, providing novel insights into metabolic adaptations associated with obesity and weight loss interventions. EVs, particularly CD9+ and CD63+ subpopulations, emerge as potential candidates for further exploration of protein-level changes to better delineate their functional roles in mediating inflammation and metabolic dysfunction, and potential involvement in the obesity-cancer connection. Citation Format: Faiza Kalam, Kalpana Deepa Dorayappan, Rand T. Akasheh, Zhipeng Tao, Ting-Yuan David Cheng, Krista Varady, Selvendiran Karuppaiyah. Extracellular vesicle dynamics in alternate-day fasting combined with low-carbohydrate weight loss intervention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3728.