The authors examined the effects of
splenectomy on serum
lipids in patients with
hematologic disease, in rabbits, and also in
cholesterol-fed rabbits with experimental
atherosclerosis. Serum
cholesterol was determined in patients with
hypersplenism before and after
splenectomy. Meanwhile serum
lipids were determined in two groups of rabbits:
splenectomy group (Spx group, n = 19), and
sham operation group (
Sham group, n = 14) before and after the operation. Then the rabbits were divided into four subgroups:
cholesterol-fed groups--Spx-C (n = 12) and
Sham-C (n = (9), and normal-chow-fed groups--Spx-N (n = 7) and
Sham-N (n = 5). The Spx-C and the
Sham-C rabbits were fed 1%
cholesterol diet and the Spx-N and
Sham-N rabbits were fed normal chow for twelve weeks. In patients preoperative serum
cholesterol levels were low, and significant increase in serum
cholesterol was observed following
splenectomy. In rabbits, the Spx-C group showed significantly higher levels of serum
cholesterol,
triglycerides, and
phospholipids in contrast to lower levels of
high density lipoprotein cholesterol, as compared with the
Sham-C group. The percentage of aortic plaque area in the Spx-C group tended to be higher than that in the
Sham-C group. On the other hand, the Spx-N and the
Sham-N group showed no difference in serum
lipids during twelve weeks. The worsening of
atherosclerosis in the Spx-C group was considered to be mainly due to an enhanced
hyperlipidemia. Their results suggest a possible role of the spleen in lipid metabolism, in particular the existence of a splenic factor that can cause hypocholesterolemia in hyperplenism and can suppress
hyperlipidemia.