閉塞性動脈硬化症における赤血球変形能とpentoxifylline投与の効果

Abstract

Red cell deformability is very important for microcirculation in arteriosclerosis obliterans (ASO). RBC deformability in ASO patients was measured by a modification of Reid's method using a 5-μm pore Nuclepore Micro Filter and a 20% Ht red cell suspension. The flow rate of a 20% Ht suspension through the filter was calculated, and red cell filtration rate (RFR) was used as an estimate of red cell deformability.RBC deformability in 34 ASO patients (mean age: 64.2 years) was reduced (RFR=32.32 pl/sec) significantly, compared with 17 age-matched controls (mean age: 59.0 years RFR=50.01μl/sec) (p<0.001). RBC deformability in ASO was also analyzed by allotting the patients into a claudication group and an ulcer group. The mean RFR in the claudication group (n=23) was 35.33μl/sec while that in the ulcer group (n=5) was 5.74μl/sec. The RBC deformability in the ulcer group was thus singificantly lower than that in the claudication group (p<0.001).Pentoxifylline was given orally to 9 patients in a dose of 600mg per day for 6 weeks. The mean RFR pre-treatment was 32.18μl/sec. The mean RFR post-treatment increased to 59.40μl/sec (p<0.01). Pentoxifylline was proven to be very effective for improving not only reduced RBC deformability but also clinical signs and symptoms.Ehrly pointed out that one of the factors governing the microcirculatory blood maldistribution was the reduced red cell deformability in occlusive arterial disease. The cause of this reduced RBC deformability in ASO, however, is still unknown. We have shown that reduced red cell deformability was improved after prostaglandin E1 and PGI2 analogue treatment. On the other hand, the productivity of PGI2 in ASO was proven to be lowered. These findings indicate that there may be some relationship between PGI2 and RBC deformability in ASO.Because red cell deformability was reduced significantly in the ulcer group, this lowered deformability might be a cause and a consequence of the ulcer in ASO patients. On the other hand, the ATP level in poorly deformable RBC is known to be below normal. Furthermore in vascular disease, the ATP level in RBC is reportedly lower than in normal controls. Pentoxifylline is thought to improve reduced RBC deformability in ASO by increasing the ATP level in RBC.