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Cartilage tissue engineers have made great inroads on understanding the factors controlling chondrogenesis, however, the biomechanical properties of tissue engineered cartilage (TEC) are chronically inferior to that of native cartilage. The focus of this dissertation was to determine the ability of scaffold-free TEC to withstand frictional-shear stress, and if needed, to improve that ability to a physiologically relevant level. Frictional-shear testing performed at a sub-physiological normal stress of 0.55 MPa demonstrated that constructs exhibited lubrication patterns characteristic of native cartilage lubrication, but severe damage also occurred. Low absolute collagen content, and a low collagen-to-glycosaminoglycan (GAG) ratio were also found in the same constructs. Reduction in damage was attempted by increasing the collagen content of the ECM.Scaffold-free TEC treated with T4 at 25 ng/ml exhibited increased collagen concentration in a statistically significant manner, and the average collagen-to-GAG ratio was also increased although statistical significance was not achieved. Western blotting showed that type II collagen was increased, type X collagen was not detected. COL2A1, and biglycan gene expression were also found to have increased, no statistically significant difference was found for COLX gene expression.When compared to control constructs, T4 treated constructs exhibited a large and statistically significant decrease in the extent of damage incurred by frictional-shear testing. At the 2.8 MPa normal stress, total damage was reduced by 60% in the 2-month constructs. Correlation coefficients calculated between compositional properties and the amount of damage showed that at the 2.8 MPa normal stress collagen concentration and the collagen-to-GAG ratio exhibited the greatest correlation to damage (correlation coefficient of approximately -0.7 with a 95% confidence interval of approximately -0.87 to -0.38 for both).In conclusion, scaffold-free cartilage generated without special attention to increasing collagen content may be highly susceptible to damage from frictional-shear stress. Furthermore, the collagen-to-GAG ratio appears to be an important property in determining damage susceptibility. Collagen content can be improved by use of T4. Presumably as a result of the increased collagen content, scaffold-free TEC treated with T4 was able to withstand frictional-shear testing at physiologically relevant normal stresses.

Cardiovascular disease is now the leading cause of death worldwide. Serum amyloid A (SAA), a positive acute phase reactant, along with C-reactive protein is used clinically as a marker of cardiovascular disease risk. However, recent data has shed light on a possible causal role of SAA in the development of atherosclerosis, the most pervasive form of cardiovascular disease. Several inflammatory diseases such as diabetes and obesity are known to confer increased risk of developing cardiovascular disease. Individuals with these diseases all have modest but persistent elevation of SAA. To determine if SAA caused the development of atherosclerosis, apoe-/-chow fed mice were injected with either an adenoviral vector expressing human SAA1 (ad-hSAA1), a null adenoviral vector (ad-Null) or saline. Human SAA levels rapidly increased, albeit briefly then returned to baseline within 14 days in mice that received ad-hSAA1. After 16 weeks, mice that received ad-hSAA1 had significantly increased atherosclerosis compared to controls on the aortic intimal surface (pldlr-/- mouse on a C57BL/6 background and fed a pro-atherogenic western diet for 12 weeks. There was a significant increase in atherosclerotic lesion area on the aortic intimal surface (p

Abstract: Introduction: Partial bladder outlet obstruction (pBOO) is a significant problem that can affect renal health. We hypothesize that changes occur in small leucine-rich proteoglycan (SLRP) composition of extracellular matrix over time in this process. We hypothesize that medical treatment of this condition will improve functional and molecular outcomes. Methods: Rats underwent surgical pBOO for 4-16 weeks time, and were compared to shams and untreated control animals. Urodynamic measurements were taken, bladders were weighed, measured for thickness, and frozen for RT-PCR and mass spectrometry. Results: Decorin and biglycan were found to be inversely related over the course of pBOO, with decorin decreasing in RNA and protein expression, and biglycan increasing. Treatment of animals with oxybutynin or tadalafil resulted in favorable urodynamic, histologic and molecular changes. Conclusion: SLRPs are differentially regulated in pBOO. Treatment with oxybutynin or tadalafil delayed progression of pBOO pathology. We believe that the process of pBOO is medically alterable.

Bone is an exquisitely evolved connective tissue that serves structural and metabolic roles in the body. Bone fragility leading to fracture is a significant medical and economic burden facing our society. Each year, 1.5 million Americans suffer an age-related fracture, resulting in direct-care expenditures of 18 billion dollars a year and often leading to decreased quality of life or even death. Animals with targeted mutations in a bone matrix protein (KO) are utilized to study the protein’s roles in regulating extracellular matrix (ECM) deposition and architecture and understanding how these functions relate to bone disease and fracture etiology. The importance of skeletal loading for the maintenance/increase of bone mass was suggested as early as 1892. In addition to increased size, mechanical loading influences bone ECM quality. Since many diseases influence the mechanical integrity of bone through altered tissue quality, mechanical stimulation may be a practical way to prevent/treat ECM deficiencies. Mouse inbred strain-specific responses in bone have been demonstrated following mechanical stimulation and bone regeneration. No study has demonstrated that the response to a genetic deletion can exhibit inbred-strain-specific characteristics, or that phenotypic changes can be modulated with mechanical stimulation. It was hypothesized that the response to a genetic deletion (the bone matrix protein biglycan, bgn), mechanical stimulation (running) and a combination of these two variables would display inbred-strain-specific characteristics in the tibiae of C57BL6/129 (B6;129) and C3H/He (C3H) male mice. This dissertation establishes for the first time that an inbred strain-specific response to genetic deletion exists, further develops the roles that biglycan plays in regulating collagen and mineral in vivo and links these in vivo roles with mechanical integrity. Without addition of new bone, exercise altered the pre-existing ECM which influenced tissue quality and mechanical integrity. In B6;129 KO, exercise-induced changes in tissue composition compensated for tissue-level mechanical deficiencies, suggesting that mechanical stimulation may be effective as a therapeutic intervention for diseases associated with deficiencies in bone quality. These studies provide new insights into inbred strain research which has important implications to the proper interpretation of investigations into the effects of genetic deficiencies and loading on the skeleton.