Encapsulated human primary myoblasts deliver functional hFIX in hemophilic mice

Jianping Wen, Nong Xu, Anna Li, Jacqueline Bourgeois, Frederick A. Ofosu, Gonzalo Hortelano

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16 Citations (Scopus)


Background: Hemophilia B is a bleeding disorder caused by defective factor IX (FIX), currently treated by regular infusions of plasma-derived or recombinant FIX. We propose a gene therapy strategy based on the implantation of cells secreting FIX enclosed in alginate microcapsules as a highly desirable alternative treatment. We have reported sustained delivery of human factor IX (hFIX) in immunocompetent mice implanted with encapsulated primary mouse myoblasts engineered to secrete hFIX. As a step towards the treatment of human patients, in this study we report the implantation of encapsulated human primary myoblasts secreting hFIX in hemophilia B mice. Methods: Human primary myoblasts were transfected with plasmids pKL4M-hFIX, pLNM-βIXL, pMFG-hFIX, and transduced with retrovirus MFG-hFIX. Two human primary myoblast clones secreting ∼1 μg hFIX/106 cells/day were enclosed in biocompatible alginate microcapsules and implanted intraperitoneally into SCID and hemophilic mice. Results: Circulating hFIX (peak of ∼120 ng/ml) was detected in hemophilia B mice on day 1 after implantation. Human FIX delivery was transient, however, becoming undetectable on day 14. Concurrently, anti-hFIX antibodies were detected. At the same time, activated partial thromboplastin time (APTT) was reduced from 94 s before treatment to 78-80 s. Tail bleeding time decreased from 15 min to 1.5-7 min after treatment, some mice being normalised. These findings indicate that the delivered hFIX is biologically active. Similarly treated NOD/SCID mice had circulating hFIX levels of 170 ng/ml on day 1 that remained detectable for 1 month, albeit at low levels. Cell viability of microcapsules retrieved on day 60 was below 5%. Conclusions: Our findings indicate that encapsulated human primary myoblasts secrete functional hFIX. Furthermore, implantation of encapsulated human primary myoblasts can partially correct the phenotype of hemophilia B mice, supporting the feasibility of this gene therapy approach for hemophilia B. However, the long-term viability of the encapsulated human myoblasts must first be improved.

Original languageEnglish
Pages (from-to)1002-1010
Number of pages9
JournalJournal of Gene Medicine
Issue number11
Publication statusPublished - Nov 2007


  • 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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