Association between hemoglobin level and endothelial function in uncomplicated, untreated hypertensive patients.
OBJECTIVE
Hemoglobin (Hb) is an important nitric oxide (NO) buffer and a modulator of NO bioavailability. In addition, endothelial dysfunction is common in hypertensive patients, suggesting a pivotal role of hemoglobin concentration ([Hb]) in vascular function. To investigate the potential role of [Hb] in endothelium-dependent vasodilation, the relationship between Hb and endothelial function was tested in a group of patients with essential hypertension.


METHODS
In this retrospective study, 174 nonsmoking, uncomplicated, never-treated hypertensives were enrolled. Endothelium-dependent and -independent vasodilation was assessed by measurement of forearm blood flow response during intra-arterial infusion of increasing doses of acetylcholine (ACh) and sodium nitroprusside (SNP) using strain-gauge plethysmography. Correlation with established risk factors of endothelial dysfunction was performed.


RESULTS
The vasodilatory response to ACh was inversely (P < 0.001) related to [Hb], and this relationship was dose dependent (P < 0.001), being minimal at the lowest dose and maximal at the highest dose. No association was found between Hb and the vasodilatory response to SNP. In a multiple linear regression model adjusted for Framingham risk factors (age, sex, BP, cholesterol, body mass index, glucose) and emerging risk factors (homeostasis model assessment index, C-reactive protein, estimated GFR), [Hb] maintained a strong and independent link with the vasodilatory response to ACh (P < 0.001).


CONCLUSIONS
In a large group of nonsmoking untreated hypertensives, [Hb] is inversely related to forearm endothelium-dependent vasodilation. [Hb] should be taken into account, especially in conditions associated with low [Hb], when performing vascular function studies.
Internal Medicine and Cardiovascular Diseases Unit, Department of Experimental and Clinical Medicine G. Salvatore, University Magna Græcia, Catanzaro, Italy.
Raffaele
R
Maio
Angela
A
Sciacqua
Rosamaria
R
Bruni
Alessandra
A
Pascale
Giuseppe
G
Carullo
Paola E
PE
Scarpino
Desirée
D
Addesi
Ines
I
Spinelli
Giulia Galiano
GG
Leone
Francesco
F
Perticone
D000109:Acetylcholine / Q000008:administration & dosage; D000328:Adult; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology*; D007261:Infusions, Intra-Arterial; D007558:Italy; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009599:Nitroprusside / Q000008:administration & dosage; D010991:Plethysmography; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014664:Vasodilation; D014665:Vasodilator Agents / Q000008:administration & dosage
D015415:Biomarkers; D006454:Hemoglobins; D014665:Vasodilator Agents; D009599:Nitroprusside; D000109:Acetylcholine