The present invention provides oligonucleotides that inhibit the binding of miR-27a to VE-cadherin mRNA, particularly in the form of blockmirs. The invention also provides compositions comprising such oligonucleotides and methods of use of such oligonucleotides to modulate the activity of VE-cadherin, inhibit or reduce vascular permeability, treat or prevent a vascular permeability-associated disease or condition, inhibit tumor growth, treat ischaemic injury, enhance recovery from ischaemic injury, treat surgical wounds and/or promotes post-operative recovery, and promote or induce angiogenesis.