Date of Award:

5-2011

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Biological and Irrigation Engineering

Advisor/Chair:

Soonjo Kwon

Abstract

In recent years, respiratory diseases have emerged as a leading cause of mortality across the globe. In the United States alone respiratory diseases are the fourth leading cause of deaths annually. Moreover, with the rapid increase of industrialization and urbanization, the occurrences of respiratory diseases are expected to remain high with strong chances of increasing in the future. To ameliorate the epidemic of respiratory disease, it is first important to understand its underlying mechanisms.

Respiratory research studies in animals have elucidated the chronological order of the pathological events and systemic responses inside the lung, but understanding the response of individual cell types inside the lung is necessary to outline the initiators and mediators of the pathological events. Many research studies have aimed to understand the behavior of individual cell types, from the lung, under different pathological conditions specific to the respiratory system. However, the cell culture systems used in most of these studies were limited by the absence of the dynamic cell growth environment present in actual lung tissues. The lung exists in a mechanically active environment, where different amounts of circumferential and longitudinal expansion and contraction occur during breathing movements. Thus, simulating the biomechanical environment in in vitro cell culture models may improve the cellular functionality and the outcome of the research studies. Moreover, the stimulation of biomechanical forces in in vitro cell cultures provides the advantage of mimicking the mechanical environment, related to different pathological conditions.

In our study we used a dynamic in vitro cell culture system capable of implementing cyclic equibiaxial deformation in cell monolayers to stimulate different biomechanical environments similar to conditions inside the lung. The dynamic cell growth condition was used to determine the effects of ventilator-induced lung injury and nano-material/pollutant exposure in A549 cell cultures. Examples of such pollutants are diesel particulate matter, multi-walled carbon nanotubes, and single-walled carbon nanotubes. Our results indicated that the dynamic cell growth condition specific to ventilator induced lung injury facilitated an increase in inflammatory and tissue remodeling activities in A549 cells. Under the nano-material/pollutant exposure assessment studies, the dynamic cell growth condition induced changes in inflammation and oxidative stress level which closely resembled those in in vivo studies.

Comments

This work made publicly available electronically on May 11, 2011.

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