Calcific aortic valve disease (CAVD) affects 25% of people over 65, and the late-stage stenotic state can only be treated with total valve replacement, requiring 85,000 surgeries annually in the US alone [1]. As CAVD is an age-related disease, many of the affected patients are unable to undergo the open-chest surgery that is its only current cure. This challenge motivates the elucidation of the mechanisms involved in calcification, with the eventual goal of alternative preventative and therapeutic strategies. There is no sufficient animal model of CAVD, so we turn to potential in vitro models. In general, in vitro models have the advantages of shortened experiment time and better control over multiple variables compared to in vivo models. As with all models, the hypothesis being tested dictates the most important characteristics of the in vivo physiology to recapitulate. Here, we collate the relevant pieces of designing and evaluating aortic valve calcification so that investigators can more effectively draw significant conclusions from their results.

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Cadherin-11 (CDH11) is upregulated in a variety of fibrotic diseases, including arthritis and calcific aortic valve disease. Our recent work has identified CDH11 as a potential therapeutic target and shown that treatment with a CDH11 functional blocking antibody can prevent hallmarks of calcific aortic valve disease in mice. The present study investigated the role of CDH11 in regulating the mechanobiological behavior of valvular interstitial cells believed to cause calcification. Aortic valve interstitial cells were harvested from Cdh11+/+, Cdh11+/−, and Cdh11−/− immortomice. Cells were subjected to inflammatory cytokines transforming growth factor (TGF)-β1 and IL-6 to characterize the molecular mechanisms by which CDH11 regulates their mechanobiological changes. Histology was performed on aortic valves from Cdh11+/+, Cdh11+/−, and Cdh11−/− mice to identify key responses to CDH11 deletion in vivo. We showed that CDH11 influences cell behavior through its regulation of contractility and its ability to bind substrates via focal adhesions. We also show that transforming growth factor-β1 overrides the normal relationship between CDH11 and smooth muscle α-actin to exacerbate the myofibroblast disease phenotype. This phenotypic switch is potentiated through the IL-6 signaling axis and could act as a paracrine mechanism of myofibroblast activation in neighboring aortic valve interstitial cells in a positive feedback loop. These data suggest CDH11 is an important mediator of the myofibroblast phenotype and identify several mechanisms by which it modulates cell behavior. NEW & NOTEWORTHY Cadherin-11 influences valvular interstitial cell contractility by regulating focal adhesions and inflammatory cytokine secretion. Transforming growth factor-β1 overrides the normal balance between cadherin-11 and smooth muscle α-actin expression to promote a myofibroblast phenotype. Cadherin-11 is necessary for IL-6 and chitinase-3-like protein 1 secretion, and IL-6 promotes contractility. Targeting cadherin-11 could therapeutically influence valvular interstitial cell phenotypes in a multifaceted manner.

Infrared neural stimulation (INS) is becoming an important complementary tool to electrical stimulation. Since the mechanism of INS is photothermal, describing the laser-induced heat distribution is fundamental to determining the relationship between stimulation pulses and neural responses. This work developed both a framework describing the time evolution of the heat distribution induced by optical fluence and a new method to extract thermal criteria (e.g., temperature change and rate of change) for neural activation. To solve the general problem of describing the temperature distribution, a Green's function solution to the heat diffusion equation was determined and convolved with the optical fluence. This provided a solution in the form of a single integral over time, from which closed-form solutions can be determined for special cases. This work also yielded an expression for thermal relaxation time, which provides a rigorous description of thermal confinement for INS. The developed framework was then applied to experimental data from the cochlea to extract the minimum temperature increase and rate of that increase to stimulate the cochlear spiral ganglion. This result, and similar analyses applied to other neural systems, can then shed light on the fundamental mechanism for INS and aid the development of optical neuroprostheses.

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Introduction: Calcific aortic valve disease affects 25% of the Western population over 65. Dystrophic calcification is initiated by TGF-β-mediated myofibroblastic differentiation of resident aortic valve interstitial cells (AVICs), which exhibit increased cell contractility and a subsequent imbalance of intercellular tension, which is speculated to lead to apoptosis of AVICs. Cadherin-11 (CDH11), a mechanosensitive transmembrane protein involved in cell-cell adhesion, is responsible for mediating much of this intercellular tension. While cadherins are known to complex with catenins intracellularly, downstream signaling is poorly understood. Both CDH11 and α-smooth muscle actin (αSMA), a myofibroblast marker involved in cell contractility, are overexpressed in diseased human valves, though previous in vitro work suggests they have an inverse relationship. Materials and Methods: AVICs were isolated from immortalized WT, CDH11 +/- and CDH11 -/- mice. They were exposed to 24 hours of 10% equibiaxial strain on the Flexcell-4000 system to recapitulate the mechanical environment of the valves and analyzed for αSMA, β-catenin, and p120-catenin via western blot. AVICs were also seeded on collagen gels and treated with 1 ng/ml murine TGF-β1 to assay contractility or plated on coverslips and stained for myosin light chain II (MLC II). Results and Discussion: Loss of CDH11 in AVICs results in a dramatic increase in αSMA ( A ). Though this suggests the cells would be highly contractile, we observe reduced contractility in CDH11 +/- and CDH11 -/- AVICs ( B ). Increases in β-catenin and p120-catenin expression indicate dramatic changes in intracellular cadherin signaling ( A ), and immunofluorescence shows a decrease in MLC II ( C ). Thus, loss of CDH11 may prevent contraction ( B ) by either preventing linkage between contractile AVICs or preventing MLC II expression. These results indicate that CDH11 may be a promising therapeutic target for calcific aortic valve disease.

Date Presented Accepted for AOTA INSPIRE 2021 but unable to be presented due to online event limitations. Health care students are not immune to mental health challenges. An existing mental health crisis and a current climate of uncertainty and unrest call academic institutions to be proactive in providing services and environments that support student mental health and wellness. This mixed-methods study captured perceptions of more than 100 health care students from seven different professions including OT. Results can be used to inform campuswide interventions and enhancements. Primary Author and Speaker: Carol Lambdin-Pattavina Additional Authors and Speakers: Meghan Bowler, Maighan Leblanc, and Jana Montgomery