Human soluble leptin receptor number in healthy normotensive individuals with high normal blood pressure.

BACKGROUND: High normal blood pressure (BP) seems to be related to increased cardiovascular risk in healthy normotensive subjects, whereas hyperleptinemia enhances both sympathetic tone and arterial BP. The aim of our study was to determine the human soluble leptin receptor number in healthy normotensive subjects with high normal BP and to compare these findings to those of healthy normotensive individuals with normal BP levels. METHODS: We studied 36 healthy normotensive individuals with high normal BP (19 men and 17 women, mean age 42+/-8 years, body mass index [BMI] 23+/-1.5 kg/m2) and 40 healthy normotensive individuals with normal BP (23 men and 17 women, mean age 43+/-7 years, BMI 23.2+/-1.4 kg/m2). The two groups are matched for age, sex, and BMI. The human soluble leptin receptor number and immunoreactive leptin levels were determined in the study population by enzyme-linked immunoassay and radioimmunoassay, respectively. RESULTS: Mean plasma leptin levels were significantly higher, whereas mean human soluble leptin receptor numbers were lower in the group with high normal BP compared with the normotensive group (10+/-4.8 v 6+/-2.7 ng/mL, P<.001 and 18+/-7 v 27+/-9 IU/mL, P<.001, respectively). CONCLUSIONS: Our findings indicate that normotensive individuals with high normal BP have statistically significantly higher plasma leptin levels and lower numbers of human soluble leptin receptors. This observation may play a important role in the pathogenesis of cardiovascular events in this special group of patients and needs further investigation.

Adiponectin and resistin plasma levels in healthy individuals with prehypertension.

Prehypertension seems to be related to increased cardiovascular risk in healthy subjects, while hypoadiponectinemia and hyperresistinemia may contribute to insulin resistance and accelerated atherogenesis. This study investigated whether plasma levels of adiponectin (known to increase insulin sensitivity) and resistin (a protein possibly involved in inflammatory activities) are affected in healthy individuals with prehypertension, and to compare the findings to those of healthy normotensives matched for age, gender, and body mass index. Twenty-six (14 men and 12 women) healthy individuals with prehypertension (mean age, 52+/-5 years; mean body mass index, 23+/-1.5 kg/m2) and 24 healthy normotensives (13 men and 11 women; mean age 53+/-6 years; body mass index 23.2+/-1.4 kg/m2) were studied. The adiponectin and resistin plasma levels were determined by the enzyme-linked immunosorbent assay method. Plasma resistin levels were significantly higher, while adiponectin plasma levels were significantly lower, in prehypertensive subjects compared with normotensive subjects (10.62+/-3.17 ng/mL vs. 6.72+/-3.15 ng/mL and 6.26+/-2.18 mg/mL vs. 12.12+/-4.8 mg/mL; p < 0.01, respectively). The findings suggest that healthy individuals with prehypertension have significantly higher resistin plasma levels and significantly lower adiponectin plasma levels compared with healthy normotensives. These findings may represent another possible mechanism that may increase the cardiovascular risk in this special group of patients, needing further investigation.

Insulin receptor number is reduced in healthy offspring of patients with essential hypertension.

BACKGROUND: Epidemiologic studies have shown that healthy offspring of hypertensive patients exhibit many features of the metabolic syndrome, such as hyperinsulinemia, insulin resistance, and lipid disorders. Patients with essential hypertension have reduced numbers of insulin receptors. The aim of this study was to examine whether the number of insulin receptors is reduced in the erythrocytes of healthy offspring of hypertensive patients in comparison to the offspring of healthy normotensive subjects. METHODS: The study population consisted of 25 healthy offspring of patients with essential hypertension (group A) and 28 healthy offspring of healthy normotensive individuals (group B). The two groups were matched for sex, age, and body mass index. Systolic blood pressure (SBP) and diastolic blood pressure (DBP), resting heart rate (HR), plasma insulin levels, and human insulin receptor (hINR) number in erythrocytes were determined in each participant. RESULTS: Mean SBP, DBP, and resting HR were significantly higher in group A than in group B (121 +/- 13 v 110 +/- 10 mm Hg, 78 +/- 6 v 73 +/- 8 mm Hg, and 76 +/- 4 v 72 +/- 6 beats/min; P < .01, P < .05, and P < .01, respectively). Plasma insulin levels were significantly higher, whereas hINR density was significantly lower, in group A than in group B (21 +/- 7 v 15 +/- 6 pIU/mL, P < .01, and 5.6 +/- 1.4 v 6.8 +/- 1.3 receptors x 10(3)/red cell, P < .01, respectively). CONCLUSIONS: Our findings suggest that increased SBP, DBP, HR, plasma insulin levels, and decreased erythrocyte hINR density preexist in healthy offspring of patients with essential hypertension.