Hyperuricemia and high blood pressure at rest and during exercise: Guilty or innocent? The jury is still out

The effects of topiroxostat on vascular function in patients with hyperuricemia

Xanthine oxidoreductase (XOR) inhibitors, such as allopurinol and febuxostat, inhibit the catalysis of serum uric acid (SUA) synthesis. In doing so, they are thought to improve vascular endothelial function in patients with hyperuricemia and cardiovascular risk by reducing increases in SUA and reactive oxygen species levels. We performed a retrospective cohort study to evaluate the effects of topiroxostat, a novel XOR inhibitor, on vascular function measured by flow-mediated dilation (FMD) on ultrasonography. In total, 23 patients with hyperuricemia were enrolled. After approximately 8 weeks, topiroxostat was associated with a significant increase in the peak percentage change in diameter (∆FMD) from 4.53% ± 2.09% to 5.54% ± 3.08% (P = .045). It also significantly reduced the SUA levels from 7.31 ± 1.43 to 5.44 ± 1.11 mg/dL (P < .001). Although further studies are needed to validate these results, it appears that topiroxostat improves vascular endothelial function in patients with hyperuricemia.

Gender- and Age-Specific Differences in the Association of Hyperuricemia and Hypertension: A Cross-Sectional Study

OBJECTIVE

Both hyperuricemia and hypertension have important clinical implications, but their relationship in terms of gender and age is still a matter of debate. In this study, we aimed to explore gender- and age-specific differences in this association between hyperuricemia and hypertension in a Chinese population.

METHODS

A total of 78596 ostensibly healthy subjects (47781 men and 30815 women) were recruited. The association between hyperuricemia and hypertension was analyzed by multivariate logistic regression, and the analyses were stratified by gender and age.

RESULTS

Overall prevalence of hypertension and hyperuricemia was significantly higher in males than in females. Increasing trends of hypertension prevalence in both genders as well as hyperuricemia prevalence in females were found along with aging. However, males showed a reduced trend in hyperuricemia prevalence with aging. Higher hypertension and hyperuricemia prevalence was found in young and middle-aged men than in women, but not in elderly people older than 70 years. Significantly increased risk of hypertension from hyperuricemia was found only in men with an adjusted odds ratio of 1.131 (P < 0.01), especially in the middle-aged male participants. However, such significant results were not found in women. Similarly, hyperuricemia was also an independent risk factor of increased systolic blood pressure and diastolic blood pressure in males, but not in females.

CONCLUSION

We observed significantly higher overall prevalence of hyperuricemia and hypertension in men than in women. Men with hyperuricemia (particularly in middle age) had a significantly increased susceptibility of hypertension, while this significant association was not observed in women.

Blockade of enhancer of zeste homolog 2 alleviates renal injury associated with hyperuricemia

Hyperuricemia has been identified as an independent risk factor for chronic kidney disease (CKD) and is associated with the progression of kidney diseases. It remains unknown whether enhancer of zeste homolog 2 (EZH2), a histone H3 lysine 27 methyltransferase, can regulate metabolism of serum uric acid and progression of renal injury induced by hyperuricemia. In this study, we demonstrated that blockade of EZH2 with 3-DZNeP, a selective EZH2 inhibitor, or silencing of EZH2 with siRNA inhibited uric acid-induced renal fibroblast activation and phosphorylation of Smad3, epidermal growth factor receptor (EGFR), and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) in cultured renal fibroblasts. Inhibition of EZH2 also suppressed proliferation of renal fibroblasts and epithelial-mesenchymal transition of tubular cells. In a mouse model of renal injury induced by hyperuricemia, EZH2 and trimethylation of histone H3 at lysine27 expression levels were enhanced, which was coincident with renal damage and increased expression of lipocalin-2 and cleaved caspase-3. Inhibition of EZH2 with 3-DZNeP blocked all these responses. Furthermore, 3-DZNeP treatment decreased the level of serum uric acid and xanthine oxidase activity, alleviated renal interstitial fibrosis, inhibited activation of transforming growth factor-β/Smad3, EGFR/ERK1/2, and nuclear factor-κB signaling pathways, as well as reduced expression of multiple chemokines/cytokines. Collectively, EZH2 inhibition can reduce the level of serum uric acid and alleviate renal injury and fibrosis through a mechanism associated with inhibition of multiple signaling pathways. Targeting EZH2 may be a novel strategy for the treatment of hyperuricemia-induced CKD.