OBJECTIVE: One potential mechanism through which obesity exerts adverse effects on the vascular system is by increasing aortic stiffness, a change known to be predictive of increased cardiovascular mortality. The aim of this study was to investigate the pathophysiology that links obesity to aortic stiffening. APPROACH AND RESULTS: Obese (ob/ob) mice were used to examine physical, morphological, and molecular changes in the aorta in response to obesity. ob/ob mice had increased aortic pulse wave velocity and tissue rigidity. ob/ob aorta exhibited decreases of lysyl oxidase (LOX) activity and cross-linked elastin, and increases of elastin fragmentation and elastolytic activity. The aortas of ob/ob mice were surrounded by a significant amount of proinflammatory and pro-oxidative perivascular adipose tissue. In vitro studies revealed that the conditioned medium from differentiated adipocytes or the perivascular adipose tissue of ob/ob mice attenuated LOX activity. Furthermore, inhibition of LOX in wild-type lean mice caused elastin fragmentation and induced a significant increase in pulse wave velocity. Finally, we found that obese humans had stiffer arteries and lower serum LOX levels than do normal-weight humans. CONCLUSIONS: Our results demonstrated that obesity resulted in aortic stiffening in both humans and mice, and established a causal relationship between LOX downregulation and aortic stiffening in obesity.
OBJECTIVE: One potential mechanism through which obesity exerts adverse effects on the vascular system is by increasing aortic stiffness, a change known to be predictive of increased cardiovascular mortality. The aim of this study was to investigate the pathophysiology that links obesity to aortic stiffening. APPROACH AND RESULTS:Obese (ob/ob) mice were used to examine physical, morphological, and molecular changes in the aorta in response to obesity. ob/ob mice had increased aortic pulse wave velocity and tissue rigidity. ob/ob aorta exhibited decreases of lysyl oxidase (LOX) activity and cross-linked elastin, and increases of elastin fragmentation and elastolytic activity. The aortas of ob/ob mice were surrounded by a significant amount of proinflammatory and pro-oxidative perivascular adipose tissue. In vitro studies revealed that the conditioned medium from differentiated adipocytes or the perivascular adipose tissue of ob/ob mice attenuated LOX activity. Furthermore, inhibition of LOX in wild-type lean mice caused elastin fragmentation and induced a significant increase in pulse wave velocity. Finally, we found that obesehumans had stiffer arteries and lower serum LOX levels than do normal-weight humans. CONCLUSIONS: Our results demonstrated that obesity resulted in aortic stiffening in both humans and mice, and established a causal relationship between LOX downregulation and aortic stiffening in obesity.
Authors: Zachary I Grunewald; Nathan C Winn; Michelle L Gastecki; Makenzie L Woodford; James R Ball; Sarah A Hansen; Harold S Sacks; Victoria J Vieira-Potter; Jaume Padilla Journal: Am J Physiol Regul Integr Comp Physiol Date: 2017-12-20 Impact factor: 3.619