Persistent delivery of factor IX in mice: Gene therapy for hemophilia using implantable microcapsules

Gonzalo Hortelano, Nong Xu, Andrea Vandenberg, Jesús Solera, Patricia L. Chang, Frederick A. Ofosu

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


Severe hemophilia B is a life-threatening, life long condition caused by absence of or defective coagulation factor IX. Gene therapy could provide an alternative treatment to repeated injection of plasma-derived concentrate or recombinant factor IX. We have previously described the use of implantable microcapsules containing recombinant myoblasts to deliver human factor IX in mice. This study reports the generation of improved myoblast-specific expression vectors. Mouse myoblast clones transfected with the various vectors secreted factor IX in vitro, at rates between 70 and 1000 ng/106 cells/day. The recombinant myoblast clones were then encapsulated and implanted into mice. Immunocompetent mice implanted with encapsulated myoblasts had up to 65 ng of factor IX per milliliter in their plasma for up to 14 days, after which antibodies to human factor IX became detectable, and this coincided with decreased factor IX in mouse plasma. In immunodeficient mice, however, factor IX delivery was maintained at a constant level for at least 6 weeks (end of experiment). Interestingly, the highest-secreting myoblast clone in vitro did not deliver the highest level of hFIX in vivo. This discrepancy observed between performance in vitro and in vivo may have important implications for the development of gene therapy protocols based on recombinant cells.

Original languageEnglish
Pages (from-to)1281-1288
Number of pages8
JournalHuman Gene Therapy
Issue number8
Publication statusPublished - May 20 1999

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Genetics

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