The use of fluorescent nuclear dyes and laser scanning confocal microscopy to study the cellular aspects of arterial remodelling in human subjects with critical limb ischaemia

Resistance arteries isolated from patients with critical limb ischaemia (CLI), a hypotensive/hypoperfusion state of the lower leg, have been shown to undergo morphological changes opposite to those observed in hypertension, that is, decreased wall thickness, reduced cross-sectional area and a decreased wall : lumen ratio. The aim of this present study was to use laser scanning confocal microscopy (LSCM) to study intact resistance arteries isolated from patients with CLI, specifically to identify the cellular aspects of the morphological changes identified in ischaemic subcutaneous and skeletal muscle resistance vessels. Using LSCM, a significant reduction in adventitial and medial thickness, cross-sectional area and wall : lumen ratio was confirmed in resistance arteries from both distal ischaemic subcutaneous and skeletal muscle vascular beds when compared with corresponding arteries from the proximal non-ischaemic sites. The cellular composition of the adventitial, medial and intimal layers of these distal ischaemic arteries was significantly different compared with proximal non-ischaemic arteries. These differences in the distal arteries were characterised by hypoplasia in the adventitial and medial layers of the arterial wall and hypertrophy in the intimal layer. The differences observed in both distal ischaemic vascular beds (subcutaneous and skeletal muscle) were similar.