Uric acid induces endothelial dysfunction by vascular insulin resistance associated with the impairment of nitric oxide synthesis.
Level 5 - mechanism / opinion, no new human data
Preclinical laboratory and animal study (in vitro cell culture and rat model).
PubMed 24652948 · doi:10.1096/fj.13-247148
What was done
Researchers investigated the mechanisms of uric acid-induced vascular dysfunction using human umbilical vein endothelial cells (HUVECs) and a rodent model. In HUVECs, the effects of uric acid on insulin-stimulated endothelial nitric oxide synthase (eNOS) phosphorylation, nitric oxide (NO) production, and endothelin-1 expression were tested, including transfection with p110 to evaluate PI3K/Akt pathway involvement. In vivo, rats were treated with the uricase inhibitor allantoxanamide to induce mild hyperuricemia, with or without allopurinol co-treatment, to evaluate mean arterial pressure, systemic insulin resistance, aortic Akt/eNOS signaling, and insulin-induced vasorelaxation.
What was found
In HUVECs, uric acid suppressed insulin-induced eNOS phosphorylation (IC50 51.0), NO production (IC50 73.6), and endothelin-1 expression (IC50 184.2) in a PI3K/Akt-dependent manner. In rats, allantoxanamide-induced hyperuricemia increased mean arterial pressure by 25% and impaired insulin-induced vasorelaxation by 56% with compromised aortic Akt/eNOS signaling, despite no systemic insulin resistance. Coadministration of allopurinol reduced serum uric acid and blood pressure and restored insulin-mediated Akt/eNOS signaling and vasorelaxation.
Why it matters
The study identifies a specific pathway by which hyperuricemia directly drives vascular insulin resistance and endothelial dysfunction independently of systemic insulin resistance.
Limits
The study is restricted to in vitro endothelial cell cultures and an animal model, limiting direct clinical translation to humans. Sample sizes (number of rats and experimental replicates) and units for the reported IC50 values are not stated in the abstract.
Cited by
- supports Elevated uric acid causes hypertension by inhibiting endothelial nitric oxide production.