Sustained and therapeutic levels of human factor IX in hemophilia B mice implanted with microcapsules: Key role of encapsulated cells

Jianping Wen, Andrew Gómez Vargas, Frederick A. Ofosu, Gonzalo Hortelano

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


Background: A gene therapy delivery system based on microcapsules enclosing recombinant cells engineered to secrete a therapeutic protein was explored in this study. In order to prevent immune rejection of the delivered cells, they were enclosed in non-antigenic biocompatible alginate microcapsules prior to being implanted intraperitoneally into mice. We have shown that encapsulated C2C12 myoblasts can temporarily deliver therapeutic levels of factor IX (FIX) in mice, but the C2C12 myoblasts elicited an immune response to FIX. In this study we report the use of mouse fetal G8 myoblasts secreting hFIX in hemophilia mice. Methods: Mouse G8 myoblasts were transduced with MFG-FIX vector. A pool of recombinant G8 myoblasts secreting ∼1500 ng hFIX/10 6 cells/24 h in vitro were enclosed in biocompatible alginate microcapsules and implanted intraperitoneally into immunocompetent C57BL/6 and hemophilic mice. Results: Circulating levels of hFIX in treated mice reached ∼400 ng/ml for at least 120 days (end of experiment). Interestingly, mice treated with encapsulated G8 myoblasts did not develop anti-hFIX antibodies. Activated partial thromboplastin time (APTT) of plasmas obtained from treated hemophilic mice was reduced from 107 to 82 sec on day 60 post-treatment, and whole blood clotting time (WBCT) was also corrected from 7-9 min before treatment to 3-5 min following microcapsule implantation. Further, mice were protected against bleeding following major trauma. Thus, the FIX delivery in vivo was biologically active. Conclusions: Our findings suggest that the type of cells encapsulated play a key role in the generation of immune responses against the transgene. Further, a judicious selection of encapsulated cells is critical for achieving sustained gene expression. Our findings support the feasibility of encapsulated G8 myoblasts as a gene therapy approach for hemophilia B.

Original languageEnglish
Pages (from-to)362-369
Number of pages8
JournalJournal of Gene Medicine
Issue number3
Publication statusPublished - Mar 2006
Externally publishedYes


  • Alginate
  • Factor IX
  • Gene therapy
  • Hemophilia B
  • Microcapsules
  • Myoblasts

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Genetics
  • Drug Discovery
  • Genetics(clinical)

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