Recombinant adeno-associated virus-based gene transfer of cathelicidin induces therapeutic neovascularization preferentially via potent collateral growth.
Pinkenburg. Olaf O; Pfosser. Achim A; Hinkel. Rabea R; Böttcher. Martina M; Dinges. Claudia C; Lebherz. Corinna C; Sultana. Shahana S; Enssle. Jörg J; El-Aouni. Chiraz C; Büning. Hildegard H; Boekstegers. Peter P; Bals. Robert R; Kupatt. Christian C
Key Findings
- rAAV‑mediated LL‑37 expression boosted limb perfusion by about 40% compared with controls
- The improvement came from growth of collateral vessels, not from more capillaries
- Blocking the PI3K pathway stopped the benefit, showing the mechanism depends on PI3K signaling
Practical Outcomes
- While LL‑37 shows promise as a pro‑angiogenic factor, the method used (viral gene delivery) isn’t practical for DIY or everyday use. Enthusiasts might watch for future work on direct peptide or small‑molecule ways to tap this pathway, but no immediate protocol can be recommended.
Summary
A study in rabbits showed that delivering the gene for the antimicrobial peptide LL‑37 using a viral vector (rAAV) helped grow new side‑branch blood vessels and improve blood flow in a blocked leg, but it didn’t increase tiny capillaries and the effect relied on a specific cell‑signaling pathway.
Abstract
Therapeutic neovascularization is a concept well validated in animal models, however, without clear-cut success in clinical studies. To achieve prolonged transgene expression, recombinant adeno-associated virus (rAAV) was used in a chronic ischemic hind-limb model and the human antimicrobial peptide cathelicidin (LL-37/hCAP-18) was used as proangiogenic factor. Seven days after femoral artery excision, 0.5 x 10(11) rAAV particles encoding for green fluorescent protein (rAAV.GFP), cathelicidin (rAAV.cath), or vascular endothelial growth factor A (rAAV.VEGF-A) were retroinfused into the anterior tibial vein of rabbits (n = 5 per group). In addition, one rAAV.cath-treated group obtained a constant infusion with the phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin into the ischemic tissue starting on day 7. On day 7 and day 35 angiography of both hind limbs was performed for collateral quantification and frame count score (cinedensitometry). Capillary-to-muscle fiber ratios were obtained on day 35. Compared with controls, application of rAAV.cath induced a gain of perfusion (153 +/- 12 vs. 107 + 9% of day 7 controls) via increased collateral growth (length index, 161 +/- 14 vs. 97 +/- 9%, controls), but no significant capillary growth (1.16 +/- 0.09 vs. 0.99 +/- 0.08, controls). Wortmannin application completely abolished the effects of rAAV.cath, indicating the involvement of the PI3K signal pathway. In conclusion, rAAV-mediated cathelicidin expression is capable of inducing functionally relevant neovascularization, preferentially by collateral growth. The rAAV-based vectors as long-expressing vector expression systems and cathelicidin as proangiogenic factor provide a promising new combination in the treatment of peripheral artery disease.
Study Information
pubmed
2009
2009-01-26T00:00:00.000Z
10.1089/hum.2007.178
9
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