title: Intravitreal cell-based production of glucagon-like peptide-1.
abstract: BACKGROUND
  To examine the efficacy and safety of an intravitreal cell-based production of glucagon-like peptide-1 (GLP-1) by intravitreally implanted and encapsulated cells.
  
  
  METHODS
  The experimental study included 12 Sprague-Dawley rats. Four cell beads with a diameter of 600 μm were intravitreally implanted. Each bead contained 3,000 GLP-1-secreting cells, which were encapsulated by a barium cross-linked sodium alginate matrix. At baseline and at each of the follow-up examinations at Day 3, Day 7, and Day 14, 4, 3, 3, and 2 animals, respectively, were killed. The concentration of active GLP-1 in the vitreous body samples was determined by enzyme-linked immunosorbent assay. The retinas were histologically examined.
  
  
  RESULTS
  The active GLP-1 concentration in the vitreous samples increased significantly after baseline (<5 pM) to a peak at Day 3 (287 ± 196 pM) and at Day 7 (238 ± 55 pM), before it decreased at Day 14 (70 ± 8 pM). The histologic examinations did not show signs of apoptosis or tissue destruction.
  
  
  CONCLUSIONS
  The intravitreal application of beads containing alginate-encapsulated cells producing GLP-1 resulted in an intraocular production of GLP-1 with a significant increase in the intraocular GLP-1 concentration, without observed cytotoxic effects. An intravitreal cell-based drug therapy with GLP-1 appears feasible.
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Haijuan
authors.initials: H
authors.lastname: Zhang
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.forename: Ke
authors.initials: K
authors.lastname: Ma
authors.forename: Christine
authors.initials: C
authors.lastname: Wallrapp
authors.forename: Jost B
authors.initials: JB
authors.lastname: Jonas
mesh_terms: D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D016503:Drug Delivery Systems; D019858:Enteroendocrine Cells / Q000637:transplantation; D004797:Enzyme-Linked Immunosorbent Assay; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism*; D020287:In Situ Nick-End Labeling; D054795:Incretins / Q000378:metabolism*; D008863:Microspheres; D051381:Rats; D017207:Rats, Sprague-Dawley; D014822:Vitreous Body / Q000166:cytology / Q000378:metabolism*
chemical_list: D054795:Incretins; D052216:Glucagon-Like Peptide 1