Comparison of vascular smooth muscle cells in canine great vessels

Abstract

BackgroundElucidating the histological characteristics of normal vascular smooth muscle cells (VSMCs) is important for understanding mechanisms of development, disease etiology and the remodeling and/or regeneration process of the vessel. However, knowledge regarding VSMCs is focused primarily on the artery. Although the characteristics of each great vessel are documented, few studies have examined VSMCs in parallel within each great vessel. The present study focused on comparing characteristics of canine VSMCs within the aorta (Ao), branch pulmonary artery (bPA), main pulmonary artery (mPA) and inferior vena cava (IVC), simultaneously.ResultsWestern blot and immunohistochemistry were used to determine VSMC protein content for alpha smooth muscle actin (ASMA), calponin, myosin heavy chain (MHC) and its isozyme SM2, and non-muscle myosin heavy chain B (SMemb). Thickness and ratio of the VSMC layer were also measured. Expression levels of ASMA, calponin and SM2 significantly differed between vessels, except between mPA and either bPA, Ao and IVC vessels. Expression levels of MHC were significantly different in all vessels, whilst expression of SMemb was significantly different in the Ao compared with either bPA and mPA vessels. All vessels were significantly different with respect to total wall and VSMC layer thickness. The ratio between VSMC layer and total wall thickness was significantly different for each vessel, except between bPA and mPA vessels. Histological analysis of the IVC revealed that the VSMC layer does not line evenly and continuously through the long axis or transverse sections. With respect to the pulmonary artery, calponin was expressed to a greater extent in the mPA compared with the bPA (P < 0.01*). In contrast, MHC and SM2 were expressed to a greater extent in the bPA compared with the mPA (P < 0.01*). Differences in VSMC distribution indicate structural differences in the proximal and distal pulmonary artery bifurcation.ConclusionOur results show that the VSMC expression pattern in each great vessel is unique and suggestive of the developmental differences between great vessels. We believe this study provides basic data for the pathology, etiology and regenerative capability of the vessels.

Evaluation method for cell-free in situ tissue-engineered vasculature monitoring: Proof of growth and development in a canine IVC model

“…Approximately 10–15 ml of angiographic agent was injected to evaluate the features of the iTEV, IVC, and HV with breath-holding to avoid respiratory fluctuation. No anticoagulants were administered until euthanasia was performed [ 1 – 5 , 10 ]. All angiographic data were saved to digital devices for further analysis.…”

“…We previously reported the usefulness of a tissue-engineered graft (TEG) created with a biodegradable scaffold to accomplish vascular continuity in animal models [ 1 – 5 ] and clinical applications [ 6 – 9 ]. Implanted biodegradable materials act as templates for invasive cells from surrounding tissues, seeded cells, and/or newly generated tissues.…”

Vascular Smooth Muscle Cell

“…In order to meet distinct physiological requirements, different regions of the vasculature exhibit different physical properties. Early studies have shown that the VSMCs of the proximal large vessels (which comprises the arch of the aorta, the common carotids, the common pulmonary trunk, and the brachiocephalic artery) are derived from the neural crest (NC) (ectomesenchymal smooth muscle) [5,6], while VMSCs of the distal vessels (which includes the abdominal aorta and the right and left carotid arteries) are derived from the mesenchyme [7,8]. At the region of the interface of these vessels, VSMCs are derived from mixed origins, both of the ectomesenchymal and mesenchymal.…”

RNAi therapy to the wall of arteries and veins: anatomical, physiologic, and pharmacological considerations

“…Not surprisingly, relevant differences exist amongst the same cell type (EC or VSMC) within the separate vascular beds. A study comparing canine VSMCs within the aorta (Ao), branch pulmonary artery (bPA), main pulmonary artery (mPA) and inferior vena cava (IVC) revealed not only obvious histologic differences in layer thickness and cellular organization, but also significant protein expression differences with regards to smooth muscle actin (SMA), myosin heavy chain (MHC) and smooth muscle myosin heavy chain isoform 2 (SM2) [ 30 ].…”