The concentration of protein-compounds in interstitial tissue of patients with chronic critical limb ischaemia and oedema

Background: Many of chronic critical limb ischaemia (CLI) patients have dis tal leg and foot oedema. Previous electronmicroscopic studies have shown th at chronic severe ischaemia ma), cause hypoxic damage of the capillary endo thelium, including morphological changes i.e. multiplicated/thickened basal lamina, and formation of interendothelial gaps. To assess the functional c onsequences of these morphologic derangements, where proteins can leak thro ugh, we investigated the composition of the interstitial fluid in oedematou s ischaemic limbs. Patients and methods: Nine female and 3 male patients with a mean age of 79 +/- 7.9 years were included. All had unilateral CLI and peripheral pitting oedema. Leg and foot volume was measured with wafer displacement volumetry . Blister suction technique was used to collect subcutaneous interstitial f luid. The concentration of albumin, transferin, immmoglobulin G and alpha ( 2)-macroglobulin in plasma and blister fluid was measured by immunoturbidim etry. Nine patients, 8 women and 1 man with a mean age of 83 +/- 5.5 years with a proximal femur fracture sewed as an age-matched control group. Results: The mean concentration of albumin in blister fluid was significant ly lower in the patients, whereas the mean concentration of alpha (2)-macro globulin in blister fluid did not differ between patients and controls. Mea n ratio between concentrations in blister and serum of albumin, transferin and immunoglobulin G in the limbs with CLI and oedema were significantly lo wer than respective values in the control group. However there was no signi ficant difference in the ratio of alpha (2)-macroglobulin between these gro ups. Conclusion: A higher transcapillary concentration gradient for proteins in CLI limbs signifies an increase in the net osmotic pressure gradient across the capillary wall, which may be a potential oedema limiting factor