Effects of Splenectomy on Serum Lipids and Experimental Atherosclerosis

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 the Sham-N rabbits were fed normal chow for twelve weeks. In patients preop erative serum cholesterol levels were low, and significant increase in serum cho lesterol was observed following splenectomy. In rabbits, the Spx-C group showed significantly higher levels of serum cholesterol, triglycerides, and phos pholipids 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.