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Growth Responses Following a Single Intra-Muscular hGH Plasmid Administration Compared to Daily Injections of hGH in Dwarf Mice

[ Vol. 12 , Issue. 6 ]

Author(s):

Eliza Higuti, Claudia R. Cecchi, Nelio A.J. Oliveira, Daniel P. Vieira, Thomas G. Jensen, Alexander A.L. Jorge, Paolo Bartolini and Cibele N. Peroni   Pages 437 - 443 ( 7 )

Abstract:


In previous work, sustained levels of circulating human growth hormone (hGH) and a highly significant weight increase were observed after electrotransfer of naked plasmid DNA (hGH-DNA) into the muscle of immunodeficient dwarf mice (lit/scid). In the present study, the efficacy of this in vivo gene therapy strategy is compared to daily injections (5 g/twice a day) of recombinant hGH (r-hGH) protein, as assessed on the basis of several growth parameters. The slopes of the two growth curves were found to be similar (P>0.05): 0.095 g/mouse/d for protein and 0.094 g/mouse/d for DNA injection. In contrast, the weight increases averaged 35.5% (P<0.001) and 23.1% (P<0.01) for protein and DNA administration, respectively, a difference possibly related to the electroporation methodology. The nose-to-tail linear growth increases were 15% and 9.6% for the protein and DNA treatments, respectively, but mouse insulin-like growth factor I (mIGF-I) showed a greater increase over the control with DNA (5- to 7-fold) than with protein (3- to 4-fold) administration. The weight increases of several organs and tissues (kidneys, spleen, liver, heart, quadriceps and gastrocnemius muscles) were 1.3- to 4.6-fold greater for protein than for DNA administration, which gave a generally more proportional growth. Glucose levels were apparently unaffected, suggesting the absence of effects on glucose tolerance. A gene transfer strategy based on a single hGH-DNA administration thus appears to be comparable to repeated hormone injections for promoting growth and may represent a feasible alternative for the treatment of growth hormone deficiency.

Keywords:

Electroporation, gene therapy, human growth hormone, immunodeficient little mice, mouse insulin-like growth factor I, naked DNA, electroporation, gene therapy, human growth hormone, immunodeficient little mice, mouse insulin growth factor I, naked DNA, electroporation methodology, cachexia

Affiliation:

Biotechnology Department, IPEN-CNEN, Avenida Professor Lineu Prestes 2242, Cidade Universitaria, 05508-900, Sao Paulo, SP, Brazil.



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