Adipose tissue extracellular matrix and depot-specific modulation of adipocyte function in dairy cattle

Adipose tissue expansion in dairy cows involves complex interactions between adipogenesis, extracellular matrix (ECM) remodeling, and metabolic adaptations. We aimed to comprehensively investigate these processes and their implications for metabolic health, particularly in the context of ketosis, a metabolic disorder prevalent during the transition period. Subcutaneous (SAT) and visceral (VAT) adipose tissue samples were collected from postpartum dairy cows, with a focus on elucidating depot-specific differences in adipogenic capacity (AC) and ECM remodeling dynamics. Our findings revealed that SAT exhibits greater adipogenic capacity compared to VAT, characterized by increased abundance of adipose stem and progenitor cells (ASPCs), enhanced expression of adipogenic markers (ADIPOQ and FASN), and higher lipid accumulation in adipocytes. Furthermore, rheological analysis indicated that VAT possesses a stiffer ECM microenvironment compared to SAT, suggesting a potential role for depot-specific ECM in modulating adipogenesis. In parallel, our investigation into the impact of ketosis and lipid mobilization on ECM remodeling highlighted higher collagen deposition on SAT compared to VAT. Moreover, SAT demonstrated superior adaptability to changes in non-esterified fatty acids (NEFA) levels, as evidenced by higher expression of ECM remodeling markers and favorable adipokines. These findings underscore the significance of SAT in managing lipid challenges, particularly in conditions like ketosis, and highlight its crucial role in regulating lipid metabolism. Overall, our study provides comprehensive insights into the interplay between adipogenesis, ECM remodeling, and metabolic adaptations in dairy cows, shedding light on the differential responsiveness of adipose tissue depots in metabolic disorders. Understanding these mechanisms is crucial for developing targeted interventions to maintain metabolic balance and improve the overall health and productivity of dairy cows during the transition period.