Apolipoprotein E phenotype affects the malondialdehyde-modified LDL concentration and forearm endothelial function in postmenopausal women

Tsuda, Mikio
Sanada, Mitsuhiro
Higashi, Yukihito
Hara, Yoshiko
Kodama, Ichiro
Chayama, Kazuaki
Yoshizumi, Masao
Ohama, Koso

^*Department of Obstetrics and Gynaecology, Graduate School of Biomedical Science, Hiroshima University, Hiroshima, Japan
†Department of Physiology, Graduate School of Biomedical Science, Hiroshima University, Hiroshima, Japan
‡First Department of Internal Medicine, Graduate School of Biomedical Science, Hiroshima University, Hiroshima, Japan

Correspondence: Mikio Tsuda, Department of Obstetrics and Gynaecology, Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. Tel.: 81 82 257 5262; Fax: 81 82 257 5264; E-mail: [email protected]

(Received 8 May 2004; returned for revision 18 July 2004; finally revised 12 August 2004; accepted 17 September 2004)

Clinical Endocrinology 61(5):p 619-625, November 2004.

Summary

OBJECTIVE

We investigated whether the apolipoprotein E (apo E) phenotype affects the serum concentration of malondialdehyde-modified low-density lipoprotein (MDA-LDL) or forearm endothelial function in postmenopausal women.

PATIENTS AND MEASUREMENTS

Individuals were divided into three groups according to their apo E phenotype: E2 (E2/2 and E2/3, n = 12); E3 (E3/3, n = 71); and E4 (E3/4 and E4/4, n = 27). The serum concentrations of lipids and MDA-LDL were measured. Forearm blood flow during reactive hyperaemia and after sublingual nitroglycerin administration was measured by strain-gauge plethysmography.

RESULTS

The serum concentrations of total and LDL cholesterol were significantly higher in the E4 group than in the E2 group (P < 0·05) or in the E3 group (P < 0·05). The serum apo B concentration was significantly higher in the E4 group than in the E2 group (P < 0·05). The serum concentrations of high density lipoprotein (HDL) cholesterol and nitrite/nitrate were significantly lower in the E4 group than in the E2 group (P < 0·05). Other lipid concentrations did not differ in the three groups. The serum MDA-LDL concentration was highest in the E4 group, and was lowest in the E2 group (E2: 91·1 ± 6·9 IU/l, E3: 112·3 ± 5·9 IU/l, E4: 128·8 ± 9·9 IU/l; P < 0·05). The forearm blood flow response to reactive hyperaemia was lowest in the E4 group, and highest in the E2 group (E2: 52·2 ± 5·8 ml/min per 100 ml tissue, E3: 40·7 ± 1·7 ml/min per 100 ml tissue, E4: 33·4 ± 2·4 ml/min per 100 ml tissue; P < 0·05). The forearm blood flow changes in response to nitroglycerine were similar between all three groups.

CONCLUSIONS

The apo E phenotype affects the serum MDA-LDL concentration and forearm endothelial function in postmenopausal women.