title: Successful implantation of bioengineered, intrinsically innervated, human internal anal sphincter.
abstract: OBJECTIVE
  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.
authors.affiliation: GI Molecular Motors Lab, Department of Pediatrics-Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0658, USA.
authors.forename: Shreya
authors.initials: S
authors.lastname: Raghavan
authors.forename: Robert R
authors.initials: RR
authors.lastname: Gilmont
authors.forename: Eiichi A
authors.initials: EA
authors.lastname: Miyasaka
authors.forename: Sita
authors.initials: S
authors.lastname: Somara
authors.forename: Shanthi
authors.initials: S
authors.lastname: Srinivasan
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Teitelbaum
authors.forename: Khalil N
authors.initials: KN
authors.lastname: Bitar
mesh_terms: D001003:Anal Canal / Q000098:blood supply / Q000187:drug effects / Q000294:innervation* / Q000637:transplantation*; D000818:Animals; D021522:Bioartificial Organs; D002478:Cells, Cultured; D018679:Cholinergic Agonists / Q000494:pharmacology; D018920:Coculture Techniques; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005769:Gastrointestinal Motility; D006085:Graft Survival; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006727:Hormone Antagonists / Q000494:pharmacology; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009119:Muscle Contraction; D009126:Muscle Relaxation; D009130:Muscle, Smooth / Q000098:blood supply / Q000187:drug effects / Q000294:innervation* / Q000637:transplantation*; D018919:Neovascularization, Physiologic; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D018005:Receptors, Vasoactive Intestinal Peptide / Q000037:antagonists & inhibitors / Q000378:metabolism; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods*; D014183:Transplantation, Heterologous; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
chemical_list: D018679:Cholinergic Agonists; D004791:Enzyme Inhibitors; D018398:Homeodomain Proteins; D006727:Hormone Antagonists; D018005:Receptors, Vasoactive Intestinal Peptide; C064658:RAG-1 protein; D014660:Vasoactive Intestinal Peptide; D019001:Nitric Oxide Synthase