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Exaggerated Natriuresis in Essential Hypertension is not due to Increase in Renal Medullary Blood Flow
Author(s) -
Assersen K.,
Bie P.,
HoilundCarlsen P.,
Olsen M.,
Greve S.,
GamHadberg J C.,
Braad P E.,
Diederichsen A,
Mickley H.,
Damkjaer M.
Publication year - 2015
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.29.1_supplement.808.4
Subject(s) - natriuresis , medullary cavity , medicine , renal blood flow , essential hypertension , endocrinology , kidney , blood pressure
Background It has been suggested that in essential hypertension (EH) the exaggerated natriuresis (EN) is associated with an increase in renal medullary blood flow (RMBF). We aimed to measure in mildly hypertensive patients without target organ damage whether EN is associated with changes in RMBF. Methods: 7 patients (PT) with ET and 12 controls (CON) were studied, PT after 18 d of drug wash‐out incl. 4 d of low Na + diet. Testing included hemodynamic, hormonal and renal monitoring during i.v. saline loading over 4 h bracketed by non‐invasive assessment of RMBF by 15 O‐water‐ PET/CT (ref.) conducted in accordance with the Declaration of Helsinki. Results: Saline loading increased BP steadily in PT (108±3 to 117±3* mmHg) and transiently in CON (92±2† to 93±2† mmHg). Na + excretion increased 5‐fold in PT (33±7 to 150±28* µmol/min) and significantly less in CON (33±5 to 95±13*† µmol/min). RMBF did not change in PT (2.5±0.4 to 2.4±0.5 ml/g tissue/min) or in CON (3.2±0.3 to 3.1±0.2 ml/g tissue/min). Cortical blood flow did not change in PT (3.0±0.4 to 2.7±0.4 ml/g tissue/min), but decreased in CON (4.1±0.3 to 3.7±0.2 # ml/g tissue/min). # =p<0.05 within group; *: p<0.001 within group; †p<0.001 between groups. Conclusion Mild saline loading, causing 3‐ and 5‐fold increases in Na + excretion, leaves RMBF unchanged. Ref: Damkjær M. et al.: AJP Regul Integr Comp Physiol 299: R1449, 2010.Funded by Danish Heart Assoc. and Univ. of Southern Denmark.