Date of Award

Spring 5-3-2024

Level of Access Assigned by Author

Open-Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biomedical Sciences

Advisor

Lucy Liaw

Second Committee Member

Robert Koza

Third Committee Member

Calvin Vary

Additional Committee Members

Michaela Reagan

Robert Burgess

Abstract

Cardiovascular disease (CVD) is the leading cause of death in the United States and the world. Metabolic disease, diabetes, and obesity are all linked to CVD. To understand this intersection, we study perivascular adipose tissue (PVAT). PVAT surrounds most vessels and exerts a paracrine effect which changes during metabolic disease. We aim to characterize molecular features of PVAT from two human donor groups: those undergoing mitral valve replacement/repair (VR) or coronary artery bypass graft (CABG). PVAT and subcutaneous (SubQ adipose) adipose were collected, and the morphometry and protein expression were assessed using H&E and mass spectrometry. Pre-adipocytes were isolated, grown, and differentiated. We found VR donors have a lower BMI, HbA1C, and incidence of diabetes compared to CABG donors. There were no significant differences in adipocyte size, number, or stromal area between disease groups, but PVAT had more adipocytes that are smaller than SubQ adipose, within disease type. This was confirmed by parallel morphological analysis in Python. Anisotropy analysis of tissues showed both small and large scale changes between CABG PVAT and SubQ adipose PVAT, and small scale changes between VR PVAT and SubQ adipose. Proteins differentially expressed in PVAT and SubQ adipose between the v two disease groups were involved in secretion (e.g. LAMA4), insulin resistance (e.g. SYUA, PEA15), and thermogenesis (e.g. GRP75, UCP1). Upon differentiation, adipocytes derived from CABG SubQ adipose tissue expressed secretion and lipid markers. In conclusion, we found that VR donors appear to be healthier overall than CABG donors, and the cellular phenotype of the PVAT from these donors is similar. However, there are significant differences in protein signatures, suggesting that their signaling activity varies. These markers can be investigated further and potentially developed into new targets for treatment of cardiovascular disease. In addition to this characterization, we developed several 3D cell culture models of adipose tissue. These are important models because they more closely mimic the in vivo environment than traditional 2D cell culture models. These models may contribute to the future of CVD treatment and personalized medicine. In conclusion, this thesis has made significant progress in characterization adipose from multiple CVD populations and future work could help contribute to novel treatments for CVD.

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