Plasma Lipocalin-2 Concentration is Related to Blood Pressure and is Increased in Hypertension

BMY Cheung1, YC Woo1, AWK Tso1, KL Ong2, CHY Fong1, Y Wang3, A Xu3,1, KSL Lam1. 1University of Hong Kong, Department of Medicine, Hong Kong, 2Heart Research Institute, Sydney, Lipid Research Group, NSW 2042, Australia, 3University of Hong Kong, Department of Pharmacology and Pharmacy, Hong Kong

Introduction: Lipocalin-2 is secreted by adipocytes and is upregulated in obesity. As obesity is known to be a cause of hypertension, we investigated whether the plasma level of lipocalin-2 is related to blood pressure and hypertension.

Methods: The plasma concentration of lipocalin-2 was measured by immunoassay in 1925 out of 1944 subjects of the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS2), which is a cohort study of adults aged 25 or above randomly recruited from the general population in Hong Kong. Blood pressure was measured after prolonged resting by a trained nurse manually using a calibrated sphygmomanometer three times at 5 minute intervals. Sex difference was analysed using one-way ANOVA. Correlations are expressed as partial or Pearson correlation coefficients. Multiple logistic regression was used to determine the relationship between lipocalin-2 and hypertension after adjustment for age and sex. Two-sided p-values less than 0.05 were considered statistically significant.

Results: The mean age of the subjects was 52 [SD12] years and 54% were female. Plasma lipocalin-2 level was higher in men than in women (median [IQR] 37.7 -17 vs.31.6 -15, p<0.001). It was significantly related to age (r=0.15, p<0.001) and systolic blood pressure (r=0.15, p<0.001). In women but not in men, it was also significantly related to waist circumference (r=0.16, p<0.001), BMI (r=0.09, p=0.004), diastolic blood pressure (r=0.14, p<0.001) and fasting plasma glucose (r=0.089, p=0.004). Plasma lipocalin-2 level was significantly higher (p<0.001 adjusted for age) in hypertensive men and women (median [IQR] 41.1 -21; 36.5 -23) compared to normotensive men and women (36.9 -16; 30.9 -13).

Conclusion: Plasma lipocalin-2 concentration is related to systolic blood pressure, and is higher in men and in people with hypertension. Lipocalin-2 may be involved in the pathogenesis of hypertension.

Acknowledgment: Supported by RGC grant HKU780210M.