Fabrication of Myogenic Engineered Tissue Constructs

Abstract

Despite the fact that electronic pacemakers are life-saving medical devices, their long-term performance in pediatric patients can be problematic owing to the restrictions imposed by a child's small size and their inevitable growth. Consequently, there is a genuine need for innovative therapies designed specifically for pediatric patients with cardiac rhythm disorders. We propose that a conductive biological alternative consisting of a collagen-based matrix containing autologously-derived cells could better adapt to growth, reduce the need for recurrent surgeries, and greatly improve the quality of life for these patients. In the present study, we describe a procedure for incorporating primary skeletal myoblast cell cultures within a hydrogel matrix to fashion a surgically-implantable tissue construct that will serve as an electrical conduit between the upper and lower chambers of the heart. Ultimately, we anticipate using this type of engineered tissue to restore atrioventricular electrical conduction in children with complete heart block. In view of that, we isolate myoblasts from the skeletal muscles of neonatal Lewis rats and plate them onto laminin-coated tissue culture dishes using a modified version of established protocols[\(^{2, 3}\)]. After one to two days, cultured cells are collected and mixed with antibiotics, type 1 collagen, Matrigel\(^{TM}\), and NaHCO\(_{3}\). The result is a viscous, uniform solution that can be cast into a mold of nearly any shape and size[\(^{1, 4, 5}\)]. For our tissue constructs, we employ type 1 collagen isolated from fetal lamb skin using standard procedures[\(^{6}\)]. Once the tissue has solidified at 37\(^{o}\)C, culture media is carefully added to the plate until the construct is submerged. The engineered tissue is then allowed to further condense through dehydration for 2 more days, at which point it is ready for \(in\) \(vitro\) assessment or surgical-implantation.