BME PhD Preliminary Exam Announcement for Laura Nunez (A. Buganza, advisor)

Everyone is invited to attend the public presentation beginning at 9:30 am.

Title: A Multiscale Approach to Understanding Tissue Expansion-Induced Changes in Skin Mechanics and Cellular Behavior

Date: Nov 18^th

Time: 9:30 am

Location: ABE 1164

Committee members: Dr. Adrian Buganza (major professor), Dr. Luis Solorio, Dr. Marcial Gonzalez, Dr. Deva Chan

Abstract:

Breast cancer is the most diagnosed cancer in women in the US. Approximately 35% of patients opt for or are advised to undergo a mastectomy. After removal, patients can undergo Breast Reconstruction Surgery (BRS), mostly done with Tissue Expansion (TE). TE complications include necrosis, excessive asymmetry, and capsular contraction, as TE is alternated with Radiotherapy (RT). Unfortunately, little is known about the cellular processes that drive those changes and the combined effect of TE and RT on skin tissue and cells. The present study aims to quantify tissue changes, such as skin stiffness, through biaxial testing, collagen architecture changes through histology analysis, and cellular changes through protein quantification. Collected and reported data will feed a TE multiscale model to predict growth and inform BRS protocols.

We will use a porcine model with applied TE and RT for mechanical testing and histology analysis. From this model, we will quantify the cellular expression of mechanoresponsive proteins such as YAP and TE-induced area growth. Moreover, we will create a 3D culture that mimics the cell environment under TE and RT to translate our results to the human case. This 3D model will have dermis-like fibrillar hydrogels and human skin cells. We will quantify protein expression, growth, and mechanical properties, as done in the animal model. We expect the nuclear YAP activation, collagen production, and proliferative activity to increase with stretching time. We also expect the hydrogel stiffness to correlate with fiber network changes. We will describe the multiscale TE dynamics with a cell signaling model linked to a tissue physical model. This study will provide a multiscale characterization of the skin tissue and cellular activity when they undergo TE. Our results will help elucidate critical factors in the BRS process that will help design better protocols to diminish adverse effects.