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Urinary C‐Reactive Protein Excretion Increases in Angiotensin II‐Dependent Hypertensive Rats
Author(s) -
Ortiz Rudy M,
Gravano David,
Torres Samantha N,
Grewal Jasreet,
Mamalis Andrew,
Conte Debra A,
Navar L Gabriel
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a756-d
Subject(s) - angiotensin ii , renin–angiotensin system , endocrinology , excretion , medicine , urinary system , chemistry , blood pressure
Angiotensin II induces an inflammatory response characterized by an increase in serum C‐reactive protein (CRP). Our goal was to develop a method to quantify the urinary excretion of CRP as a means to evaluate the progression of the inflammatory response during Ang II‐dependent hypertension since daily urine collections are logistically more feasible than that of serum. Daily urine samples were collected from control (n = 10) and Ang II‐infused (n = 10; 60 ng/min for 28 d) male, Sprague‐Dawley rats. Plasma CRP and immunoreactive CRP (irCRP) fragments in urine were extracted using immobilized p ‐aminophenyl phosphoryl choline and analyzed by ELISA. Mean arterial pressure was increased in Ang II rats (136 ± 5 vs. 207 ± 8 mmHg). Mean plasma CRP increased 79 % (14.3 ± 1.2 vs 25.6 ± 2.5 ug/mL) after 28 d and values were significantly (p = 0.002) correlated with excreted irCRP on day 28 (Excreted CRP (ug/d) = −0.55 + 0.06 Plasma CRP (ug/mL)). Excreted irCRP was increased 27 % after 1 week, 2‐fold after 2 weeks, and 9‐fold (143 ± 26 vs. 1278 ± 273 ng/d) after 4 weeks. The positive correlation between plasma and excreted CRP suggests that excreted irCRP accurately reflects changes in circulating concentrations. Our urinary CRP protocol provides a novel index to non‐invasively monitor the progression of Ang II‐induced inflammation. Research supported by NIH NRSA (F32 HL076985 to RMO) from NHLBI, NHLBI grant (HL 26371 to LGN), NIH COBRE grant (P20 RR017659), and Millenium Health Excellence Fund from the Louisiana Board of Regents.