Disturbed ratio of erythrocyte and plasma S-adenosylmethionine/S-adenosylhomocysteine in peripheral arterial occlusive disease

Altered homocysteine metabolism associated with peripheral arterial occlusive disease (PAOD) may lead to impairment of vital methylation reactions through accumulation of S-adenosylhomocysteine (AdoHcy) as well as through alteration of the ratio S-adenosylmethionine (AdoMet)/AdoHcy. We determined AdoMet, AdoHcy, their ratio, and homocysteine in plasma as well as AdoMet, AdoHcy, and their ratio in erythrocytes of 61 patients with PAOD (age 49–93) and 50 healthy controls (age 41–87). Geometric mean values of plasma homocysteine, AdoMet, and AdoHcy were significantly increased in patients compared with controls (15.5 vs. 10.4 μmol/l**; 107 vs. 52.3* nmol/l; 55.0 vs. 23.1** nmol/l, respectively; *P<0.01, **P<0.001), while the ratio of AdoMet/AdoHcy was decreased in patients (1.92 vs. 2.52*). In erythrocytes patients exhibited increased levels of AdoHcy compared with controls (309 vs. 205 nmol/l**) whereas AdoMet (3351 vs. 3732 nmol/l*) and the ratio of AdoMet/AdoHcy (11.8 vs. 19.1**) were decreased. The odds ratio (OR) for developing PAOD with decreased AdoMet/AdoHcy ratio after adjustment for kidney function was significant for erythrocyte levels ≤14.2 (OR, 7.1 (6.9–7.2, 95% CI). In addition, hematocrit levels were found to be significantly decreased in patients versus controls (0.35 vs. 0.42 l/l**) and were significantly correlated with the ratio of AdoMet/AdoHcy in erythrocytes of the patients. Since the ratio of AdoMet/AdoHcy is closely linked with the activity of numerous enzymatic methylation reactions, these results suggest that methylation may be impaired in these patients.