Quarti Trevano Fosca, Seravalle Gino, Macchiarulo Mario, Villa Paolo, Valena Carlo, Dell'Oro Raffaella, Mancia Giuseppe, Grassi Guido
aClinica Medica, Dipartimento di Medicina e Chirurgia, Università Milano-Bicocca bIstituto Auxologico Italiano, Ospedale San Luca cIRCCS Multimedica, Milano, Italy.
J Hypertens. 2017 Aug;35(8):1685-1690. doi: 10.1097/HJH.0000000000001370.
Metabolic syndrome is characterized by a pronounced sympathetic overactivity as documented by the marked increase in muscle sympathetic nerve traffic (MSNA) as well as in plasma norepinephrine values reported in this condition. Whether and to what extent heart rate (HR) reflects the abovementioned adrenergic alterations in metabolic syndrome remains largely undefined. It is also undefined the validity of the abovementioned adrenergic markers in reflecting the main features of the metabolic syndrome.
In 65 metabolic syndrome patients, aged 56.5 ± 1.3 years (mean ± SEM), we measured over a 30-min resting period blood pressure, HR (ECG), venous plasma norepinephrine (HPLC) and MSNA (microneurography). We also evaluated anthropometric and metabolic variables including HOMA index, correlating them with the adrenergic markers. The same measurements were also made in 48 age-matched healthy controls.
HR was significantly greater in the metabolic syndrome patients than in controls (74.6 ± 1.5 versus 67.5 ± 1.5 bpm, P < 0.001) and significantly and directly correlated with the elevated norepinephrine and MSNA values (r = 0.25 and 0.33, P < 0.05 and 0.01, respectively). MSNA was significantly and directly related to blood pressure (r = 0.27 and 0.31 SBP and DBP, respectively, P < 0.05 for both), BMI (r = 0.36, P < 0.01), waist circumference (r = 0.34, P < 0.01), waist-to-hip ratio (r = 0.49, P < 0.01) and plasma insulin (r = 0.57, P < 0.01). In contrast, no significant correlation was detectable between HR or norepinephrine and the abovementioned anthropometric and metabolic variables.
Our data show that in the metabolic syndrome not only peripheral but also cardiac sympathetic drive is markedly potentiated and HR can be regarded as a marker of adrenergic overdrive characterizing this clinical condition. The reliability of HR (and of plasma norepinephrine) as sympathetic marker appears to be limited, however, this variable being unable to reflect, at variance from MSNA, the main metabolic and anthropometric abnormalities characterizing the metabolic syndrome.
代谢综合征的特征是交感神经活动明显亢进，这已被肌肉交感神经活动（MSNA）的显著增加以及该疾病中报道的血浆去甲肾上腺素值的升高所证实。心率（HR）是否以及在何种程度上反映代谢综合征中上述肾上腺素能改变在很大程度上仍不明确。上述肾上腺素能标志物在反映代谢综合征主要特征方面的有效性也不明确。
在65名年龄为56.5±1.3岁（平均值±标准误）的代谢综合征患者中，我们在30分钟的静息期测量了血压、心率（心电图）、静脉血浆去甲肾上腺素（高效液相色谱法）和MSNA（微神经ography）。我们还评估了人体测量和代谢变量，包括HOMA指数，并将它们与肾上腺素能标志物相关联。在48名年龄匹配的健康对照者中也进行了同样的测量。
代谢综合征患者的心率显著高于对照组（74.6±1.5对67.5±1.5次/分钟，P<0.001），并且与升高的去甲肾上腺素和MSNA值显著正相关（r=0.25和0.33，分别P<0.05和0.01）。MSNA与血压（收缩压和舒张压的r分别为0.27和0.31，两者P<0.05）、体重指数（r=0.36，P<0.01）、腰围（r=0.34，P<0.01）、腰臀比（r=0.49，P<0.01）和血浆胰岛素（r=0.57，P<0.01）显著正相关。相比之下，在心率或去甲肾上腺素与上述人体测量和代谢变量之间未检测到显著相关性。
我们的数据表明，在代谢综合征中，不仅外周而且心脏交感神经驱动均明显增强，心率可被视为表征这种临床状况的肾上腺素能过度驱动的标志物。然而，心率（和血浆去甲肾上腺素）作为交感神经标志物的可靠性似乎有限，与MSNA不同，该变量无法反映表征代谢综合征的主要代谢和人体测量异常。
