Similar Adiponectin Levels in Obese Normotensive and Obese Hypertensive Men and No Vasorelaxant Effect of Adiponectin on Human Arteries

Abstract

Obesity is a strong risk factor for hypertension, but the mechanism linking obesity to hypertension is not fully elucidated. In obesity, circulating concentrations of adiponectin are decreased and hypoadiponectinaemia has in some but not all studies been associated with increased risk of hypertension. Due to this inconsistency, we decided to study adiponectin from two aspects in a cross-sectional in vivo study and in an experimental in vitro study. In the cross-sectional study, 103 men with body mass index (BMI) ≥ 30.0 kg/m 2 were studied; 63 had 24-hr ambulatory blood pressure (ABP) ≥ 130/80 mmHg (ObeseHT) and 40 had 24-hr ABP < 130/80 mmHg (ObeseNT). As controls, we studied 27 men with BMI between 20.0 and 24.9 kg/m 2 and 24-hr ABP < 130/80 mmHg (LeanNT). Serum concentrations of adiponectin and body composition using dual-energy X-ray absorptiometry scanning were determined. In vitro, the direct vasomotor response of adiponectin was tested on subcutaneous resistance arteries from human abdominal adipose tissue. The two obese groups had lower adiponectin concentrations compared with LeanNT (p < 0.01) [median (interquartile range)]: ObeseHT 6.5 (5.1-8.3) mg/L; ObeseNT 6.6 (5.2-7.8) mg/L; and LeanNT 9.4 (6.7-12.4) mg/L, with no significant difference in adiponectin concentrations (or body composition) between ObeseHT and ObeseNT (p = 0.67). In vitro, adiponectin did not have any direct vasodilatory effect and adiponectin did not affect angiotensin II-stimulated vasoconstriction. In conclusion, obese hypertensive men have similar serum concentrations of adiponectin as obese normotensive men. In combination with the in vitro data, these findings question a pathogenic role of adiponectin in human hypertension.High body mass index (BMI) caused by excessive growth of adipose tissue is a major risk factor for hypertension [1], but the mechanisms by which excess adipose tissue leads to hypertension are still not fully elucidated [2,3].Over the past decades, it has become increasingly apparent that adipose tissue is not only a passive energy store, but also an active endocrine and paracrine organ that secretes various proinflammatory, vasoactive and metabolic active substances, collectively called adipocytokines or just adipokines [4][5][6][7][8]. Based on both animal and human studies, it has been suggested that these active adipose tissue-derived substances could play a role in overweight-related diseases, such as type 2 diabetes, coronary heart disease (CHD) and hypertension [4][5][6][7][8].Adiponectin, a 244 amino acid protein, which is secreted from adipose tissue, is one of these adipocytokines [4][5][6][8][9][10]. Compared with other adipocytokines, adiponectin is distinct in the sense that lower (hypoadiponectinaemia) rather than higher (hyperadiponectinaemia) circulating concentrations of adiponectin have been associated with increased risk of overweight-related diseases [4][5][6][8][9][10]. Another distinct feature is that adiponectin has been found to be inversely related to anthropometric measures, ...

Adipose-Vascular Coupling and Potential Therapeutics

“…Endothelium-dependent vasodilation by adiponectin can result from NO release via activation of guanylyl cyclase (46)(47)(48)(49) and is disturbed in leptin receptor-deficient obesity and diabetes-for example, in Zucker diabetic fatty (fa/fa) rats (50). Although adiponectin clearly plays a role in endothelial dysfunction in diabetes and obesity, recent data question a pathogenic role of circulating adiponectin in human hypertension (51,52). This view is supported by findings demonstrating that chronic centrally administered adiponectin has no effects on heart rate and blood pressure in normotensive and hypertensive rats (53).…”

Expression of endothelin type B receptors (EDNRB) on smooth muscle cells is controlled by MKL2, ternary complex factors, and actin dynamics

“…The study was approved by the Committee of Health Research Ethics in the Capital Region of Denmark (H-15005617), and informed consent was obtained in writing. Detailed procedures, including enrollment, the collection of patient data, and tissue handling, are described elsewhere (10). The Biobank of Karolinska Endarterectomies (BiKE) project is performed under Swedish biobank regulations, and prospective sampling is approved with informed consent procedure (DNr 2009/512-31/2).…”

Adipokine Profiling in Adult Women With Central Obesity and Hypertension

“…Our results indicated that the concentration of pro-inflammatory adipokine TNF-α was higher in hypertensive women with central obesity than hypertensive or obese alone women. Dreier et al reported that obese hypertensive males have similar adiponectin concentrations as obese normotensive males (Dreier et al, 2016 ). In contrast, our findings demonstrated that the concentration of anti-inflammatory adipokines (adiponectin) was lower in hypertensive adult women with central obesity.…”