Successful implantation of bioengineered, intrinsically innervated, human internal anal sphincter. Academic Article uri icon


  • BACKGROUND & AIMS: To restore fecal continence, the weakened pressure of the internal anal sphincter (IAS) must be increased. We bioengineered intrinsically innervated human IAS to emulate sphincteric physiology in vitro. METHODS: We cocultured human IAS circular smooth muscle with immortomouse fetal enteric neurons. We investigated the ability of bioengineered innervated human IAS, implanted in RAG1-/- mice, to undergo neovascularization and preserve the physiology of the constituent myogenic and neuronal components. RESULTS: The implanted IAS was neovascularized in vivo; numerous blood vessels were observed with no signs of inflammation or infection. Real-time force acquisition from implanted and preimplant IAS showed distinct characteristics of IAS physiology. Features included the development of spontaneous myogenic basal tone; relaxation of 100% of basal tone in response to inhibitory neurotransmitter vasoactive intestinal peptide (VIP) and direct electrical field stimulation of the intrinsic innervation; inhibition of nitrergic and VIPergic electrical field-induced relaxation (by antagonizing nitric oxide synthesis or receptor interaction); contraction in response to cholinergic stimulation with acetylcholine; and intact electromechanical coupling (evidenced by direct response to potassium chloride). Implanted, intrinsically innervated bioengineered human IAS tissue preserved the integrity and physiology of myogenic and neuronal components. CONCLUSIONS: Intrinsically innervated human IAS bioengineered tissue can be successfully implanted in mice. This approach might be used to treat patients with fecal incontinence.

published proceedings

  • Gastroenterology

altmetric score

  • 74.92

author list (cited authors)

  • Raghavan, S., Gilmont, R. R., Miyasaka, E. A., Somara, S., Srinivasan, S., Teitelbaum, D. H., & Bitar, K. N.

citation count

  • 61

complete list of authors

  • Raghavan, Shreya||Gilmont, Robert R||Miyasaka, Eiichi A||Somara, Sita||Srinivasan, Shanthi||Teitelbaum, Daniel H||Bitar, Khalil N

publication date

  • January 2011