Hi, my name is Depora Leavitt. And I'm Eugene Tano. Today we're going to be presenting our presentation on evaluating factors contributing to vascular calcification and aortic stiffness in an animal model of atherosclerosis. Before we get started on the poster presentation, it is essential to provide some background based on this presentation. Vascular calcification refers to the accumulation of calcium phosphate complexes within the blood. It is closely linked to the formation of atherosclerosis. Research suggests that calcification in severe atherosclerosis could result in greater stiffness of the blood vessels. In addition, different studies show discrepancies in the risk of developing atherosclerosis on the basis of sex. Some say there is an increase in males, while others say females. And some even say there is no difference at all. Males may develop the disease early, however females have accelerated disease progression post-menopause. This highlights the clinical importance of the connection and the need to look more closely at it. Another parameter we use to analyze the levels of atherosclerosis is a level of tissue not specific alkaline phosphatase, which we will refer to in the future as TNAP. TNAP has had a positive correlation with vascular calcification, which increases atherosclerosis. This suggests that a decrease in TNAP may lead to a reduction or prevention of atherosclerosis. We infer that the genetic obletion of TNAP expression in liver cells would lead to a decrease in vascular calcification. In this study, we aim to assess the TNAP model and signify the relationship between plasma alkaline phosphate levels, or as we will refer to it, ALP, and liver-specific haploinsufficiency of TNAP. Additionally, we wanted to evaluate the relationship between sex and vascular calcification. And finally, we aim to examine the effect of calcification on aortic stiffness. Liver-specific TNAP haploinsufficient mice were used to conduct this experiment. These mice and their wild-type littermates were all on the LDL receptor mutant background. In addition to being on the LDL receptor mutant background, all the mice were fed a Western diet for 52 weeks, as illustrated in Figure 1. Echocardiography was performed to assess a cardiac function and function, structure and function, and aortic stiffness was assessed by Doppler ultrasound. Some representative examples of echocardiographic images are shown in Figure 2 and 3. MicroCT was performed to measure calcification volume in the aortic root and the ascending aorta. After the results were collected, we used the GraphPad Prism 9 statistical software to analyze them. Figure 4 shows a Pearson correlation matrix, which included sex, genotype, heart rate, ejection fraction, left ventricular internal diameter and mass, pulse wave velocity as a measure of aortic stiffness, aortic root calcium volume, and ALP activity in the blood. In this figure, blue represents a positive correlation, while red represents a negative correlation. Significant values were highlighted in this figure. We then created a bar graph that highlights the significant relationship between sex and ALP, as well as haploinsufficiency and ALP levels. As shown to the left, females demonstrated significantly higher levels of ALP than males, with females having levels of 55.2 units per liter versus 41.2 units per liter in males. Additionally, in Figure 5 right, liver-specific TNAP haploinsufficiency leads to a 30% reduction of plasma ALP activity. In Figure 6 left, contrary to our hypothesis, we did not observe a significant difference in aortic root calcification in male and female subjects. In Figure 6 right, we again did not find a significant reduction in aortic root calcification in haploinsufficient mice. Next, linear regression models were created to test our associations between ALP and calcification. We found no correlation between ALP and calcification. Furthermore, we tested a correlation between aortic root calcium and pulse wave velocity, a measure of stiffness. Surprisingly, we did not find a significant correlation between aortic root calcification and aortic pulse wave velocity. Based on these results, we did not find any support for our hypothesis that sex influences calcification. Furthermore, the idea that aortic stiffness depends on vascular calcification was not supported in this animal model. It was interesting to see the relationship between ALP and its increase in females. Additionally, we found that haploinsufficiency of liver-specific TNAP can lead to a reduction in plasma ALP. Although animal models do not completely correspond to humans, these findings open more room for research and studies. In the future, being able to compare mice with a full knockout of liver TNAP may yield more significant results. Additionally, discovering the effects of females having more ALP can teach us a lot more about the physiology and progression of atherosclerosis. Again, we would like to thank you for listening to our presentation on Evaluating Factors Contributing to Vascular Calcification in Aortic Stiffness in an Animal Model of Atherosclerosis. We would like to thank our school, New York Institute of Technology, College of Osteopathic Medicine, for giving us the opportunity to work on this project. We would also like to thank Dr. Sabanova, Dr. Podalkar, and Saud Nasrudin for guiding us through this project.

vascular calcification

aortic stiffness

TNAP expression

sex differences

atherosclerosis