Smooth muscle architecture within cell-dense vascular tissues influences functional contractility

Abstract

The role of vascular smooth muscle architecture in the function of healthy and dysfunctional vessels is poorly understood. We aimed at determining the relationship between vascular smooth muscle architecture and contractile output using engineered vascular tissues. We utilized microcontact printing and a microfluidic cell seeding technique to provide three different initial seeding conditions, with the aim of influencing the cellular architecture within the tissue. Cells seeded in each condition formed confluent and aligned tissues but within the tissues, the cellular architecture varied. Tissues with a more elongated cellular architecture had significantly elevated basal stress and produced more contractile stress in response to endothelin-1 stimulation. We also found a correlation between the contractile phenotype marker expression and the cellular architecture, contrary to our previous findings in non-confluent tissues. Taken with previous results, these data suggest that within cell-dense vascular tissues, smooth muscle contractility is strongly influenced by cell and tissue architectures.

Vascular smooth muscle cell functional contractility depends on extracellular mechanical properties

“…Additionally, cell and tissue architecture within dense cultures can also affect VSMC behavior. VSMCs that are patterned into aligned tissues with elongated cell architecture exhibit a more contractile phenotype compared to non-patterned VSMCs (Williams et al, 2011), and cell architecture within a confluent tissue layer affects phenotype expression (Win et al, 2014). Here, we find that VSMC phenotype in an organized confluent layer does not depend on substrate modulus.…”

“…Microcontact printing was used to construct arterial lamella tissue mimics as in our previous publications (Alford et al, 2011a; Alford et al, 2011b; Win et al, 2014). Briefly, extracellular matrix protein, fibronectin (BD Biosciences, Radnor, PA), was stamped onto the PDMS substrate surface in 10μm parallel lines with 10μm pitch and VSMCs were seeded at 57,000 cells/cm 2 .…”

“…Fluorescent and bright field images were acquired every 30s using a Lumar V12 stereomicroscope (Zeiss, Oberkochen, Germany). These images were used to determine the 2D projection length of the film, which was used to evaluate its radius of curvature (Win et al, 2014). Data was analyzed using ANOVA and pairwise comparisons were made using the Tukey test in MATLAB.…”

“…Thus, it is important to recapitulate in vivo structure to study VSMC function in vitro. W e have previously developed vascular muscular thin film (vMTF) (Alford et al, 2010) technology to evaluate VSMC stress generation in aligned, confluent vascular lamellae mimics, but to date all vMTF studies have been performed with a single substrate modulus (Alford et al, 2011a; Alford et al, 2011b; Hald et al, 2014; Win et al, 2014). Thus, it is unclear how extracellular mechanical properties affect contractile function in confluent VSMCs with in vivo -like structure.…”

Microfluidic Genipin Deposition Technique for Extended Culture of Micropatterned Vascular Muscular Thin Films

“…Arterial lamellae are concentric, circumferentially-aligned sheets of contractile VSMCs separated by sheets of elastin 6 . Microcontact printing of extracellular matrix (ECM) proteins onto polydimethylsiloxane (PDMS) substrates has been previously used to provide guidance cues for tissue organization to mimic aligned cardiovascular tissue 5,[7][8][9][10] . However, tissues patterned using microcontact printing can lose integrity after 3-4 days in culture, limiting their applicability in chronic studies.…”