Abstract 968: Cross-Sectional Relationships of Urinary Albumin Excretion with Asymmetric Dimethylarginine and Low-Grade Inflammation in Essential Hypertension
Introduction: Asymmetric dimethylarginine (ADMA) levels are elevated in endothelial dysfunction states, whereas microalbuminuria and subclinical inflammation are associated with atherosclerosis progression.
Hypothesis: Urinary albumin excretion, expressed as the albumin to creatinine ratio (ACR), may be correlated with high-sensitivity C-reactive protein (hs-CRP) and ADMA in essential hypertensive subjects.
Methods: Our population consisted of 158 newly diagnosed untreated non-diabetics with stage I to II essential hypertension [106 men, mean age=49 years, office blood pressure (BP)= 151/97 mmHg]. According to the ACR values determined as the mean of two non-consecutive morning spot urine samples, the study population was divided into microalbuminurics (n=32) (mean ACR=30 –300mg/g) and normoalbuminurics (n=126) (mean ACR=30 mg/g). In all patients venous blood sampling was performed for estimation of hs-CRP and ADMA concentrations.
Results: Microalbuminurics compared to normoalbuminurics were older (53±7 vs 49±6 years, p<0.05), had higher 24-h systolic BP (144±11 vs 133±12 mmHg, p<0.001), while did not differ regarding sex, smoking status and metabolic profile (p=NS for all). Moreover, microalbuminurics compared to normoalbuminurics exhibited higher ADMA (0.61±0.04 vs 0.55±0.03 μmol/l, p=0.001) and hs-CRP values (4.5±1.7 vs 2±1.1 mg/l, p<0.0001). In the total population, ACR was associated with 24-h systolic BP (r=0.263, p<0.0001), ADMA (r=0.366, p<0.0001) and hs-CRP (r=0.318, p<0.0001), while ADMA was related to waist to hip ratio (r=0.208, p<0.05), and 24-h pulse pressure (r=0.604, p<0.0001). Multiple regression analysis revealed that hs-CRP (b=0.582, p<0.0001) and ADMA (b=0.238, p<0.0001) were independent predictors of ACR. Moreover, analysis of covariance showed that ADMA and hs-CRP values were significantly different between groups after adjustment for confounders (p<0.05).
Conclusion: Microalbuminuria in hypertension is associated with pronounced inflammatory activation and endothelial dysregulation, as reflected by increased hs-CRP and ADMA levels. Moreover, ACR estimation could identify hypertensive patients with vascular dysfunction associated with ADMA and hs-CRP proatherosclerotic pathways.