Aims Arterial stiffness is a hallmark of vascular ageing that precedes and strongly predicts the development of cardiovascular diseases. Age-dependent stiffening of large elastic arteries is primarily attributed to increased levels of matrix metalloproteinase-2 (MMP-2). However, the mechanistic link between age-dependent arterial stiffness and MMP-2 remains unclear. Thus, we aimed to investigate the efficacy of MMP-2 knockdown using small-interfering RNA (siRNA) on age-dependent arterial stiffness. Methods and results Pulse wave velocity (PWV) was assessed in right carotid artery of wild-type (WT) mice from different age groups. MMP-2 levels in the carotid artery and plasma of young (3 months) and old (20–25 months) WT mice were determined. Carotid PWV as well as vascular and circulating MMP-2 were elevated with increasing age in mice. Old WT mice (18- to 21-month old) were treated for 4 weeks with either MMP-2 or scrambled (Scr) siRNA via tail vein injection. Carotid PWV was assessed at baseline, 2 and 4 weeks after start of the treatment. MMP-2 knockdown reduced vascular MMP-2 levels and attenuated age-dependent carotid stiffness. siMMP-2-treated mice showed increased elastin-to-collagen ratio, lower plasma desmosine (DES), enhanced phosphorylation of endothelial nitric oxide synthase (eNOS), and higher levels of vascular cyclic guanosine monophosphate (cGMP). An age-dependent increase in direct protein–protein interaction between MMP-2 and eNOS was also observed. Lastly, DES, an elastin breakdown product, was measured in a patient cohort (n = 64, 23–86 years old), where carotid-femoral PWV was also assessed; here, plasma levels of DES directly correlated with age and arterial stiffness. Conclusion MMP-2 knockdown attenuates age-dependent carotid stiffness by blunting elastin degradation and augmenting eNOS bioavailability. Given the increasing clinical use of siRNA technology, MMP2 knockdown should be investigated further as a possible strategy to mitigate age-dependent arterial stiffness and related CV diseases.

中文翻译：

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MMP-2 敲低通过减少弹性蛋白降解和增强 eNOS 激活来减弱年龄依赖性颈动脉僵硬度

目的 动脉僵硬是血管老化的标志，它先于并强烈预测心血管疾病的发展。大弹性动脉的年龄依赖性硬化主要归因于基质金属蛋白酶 2 (MMP-2) 水平的升高。然而，年龄依赖性动脉僵硬度与 MMP-2 之间的机制联系仍不清楚。因此，我们旨在研究使用小干扰 RNA (siRNA) 敲低 MMP-2 对年龄依赖性动脉僵硬度的疗效。方法和结果 在不同年龄组的野生型（WT）小鼠的右颈动脉中评估脉搏波速度（PWV）。测定年轻（3 个月）和老年（20-25 个月）WT 小鼠的颈动脉和血浆中的 MMP-2 水平。随着小鼠年龄的增长，颈动脉 PWV 以及血管和循环 MMP-2 升高。通过尾静脉注射用 MMP-2 或乱序 (Scr) siRNA 治疗年老 WT 小鼠（18 至 21 个月大）4 周。在基线、治疗开始后 2 周和 4 周评估颈动脉 PWV。MMP-2 敲低降低了血管 MMP-2 水平并减弱了年龄依赖性颈动脉僵硬度。siMMP​​-2 处理的小鼠表现出弹性蛋白与胶原蛋白的比率增加、血浆间丝氨酸 (DES) 降低、内皮一氧化氮合酶 (eNOS) 磷酸化增强和血管环磷酸鸟苷 (cGMP) 水平升高。还观察到 MMP-2 和 eNOS 之间直接蛋白质-蛋白质相互作用的年龄依赖性增加。最后，在一个患者队列（n = 64, 23-86 岁）中测量了弹性蛋白分解产物 DES，其中还评估了颈股动脉 PWV。这里，DES 的血浆水平与年龄和动脉僵硬度直接相关。结论 MMP-2 敲低通过抑制弹性蛋白降解和增加 eNOS 生物利用度来减弱年龄依赖性颈动脉僵硬度。鉴于 siRNA 技术的临床应用越来越多，应进一步研究 MMP2 敲低作为减轻年龄依赖性动脉僵硬度和相关心血管疾病的可能策略。