The impact of an URAT1 polymorphism on the losartan treatment of hypertension and hyperuricemia

Altered Serum Uric Acid Levels in Kidney Disorders

Serum uric acid levels are altered by kidney disorders because the kidneys play a dominant role in uric acid excretion. Here, major kidney disorders which accompany hyperuricemia or hypouricemia, including their pathophysiology, are discussed. Chronic kidney disease (CKD) and hyperuricemia are frequently associated, but recent clinical trials have not supported the pathogenic roles of hyperuricemia in CKD incidence and progression. Diabetes mellitus (DM) is often associated with hyperuricemia, and hyperuricemia may be associated with an increased risk of diabetic kidney disease in patients with type 2 DM. Sodium-glucose cotransporter 2 inhibitors have a uricosuric effect and can relieve hyperuricemia in DM. Autosomal dominant tubulointerstitial kidney disease (ADTKD) is an important hereditary kidney disease, mainly caused by mutations of uromodulin (UMOD) or mucin-1 (MUC-1). Hyperuricemia and gout are the major clinical manifestations of ADTKD-UMOD and ADTKD-MUC1. Renal hypouricemia is caused by URAT1 or GLUT9 loss-of-function mutations and renders patients susceptible to exercise-induced acute kidney injury, probably because of excessive urinary uric acid excretion. Hypouricemia derived from renal uric acid wasting is a component of Fanconi syndrome, which can be hereditary or acquired. During treatment for human immunodeficiency virus, hepatitis B or cytomegalovirus, tenofovir, adefovir, and cidofovir may cause drug-induced renal Fanconi syndrome. In coronavirus disease 2019, hypouricemia due to proximal tubular injury is related to disease severity, including respiratory failure. Finally, serum uric acid and the fractional excretion of uric acid are indicative of plasma volume status; hyperuricemia caused by the enhanced uric acid reabsorption can be induced by volume depletion, and hypouricemia caused by an increased fractional excretion of uric acid is the characteristic finding in syndromes of inappropriate anti-diuresis, cerebral/renal salt wasting, and thiazide-induced hyponatremia. Molecular mechanisms by which uric acid transport is dysregulated in volume or water balance disorders need to be investigated.

The Impact of Hyperuricemia on Patients With Low Body Mass Index After Endovascular Treatments: Data From the I-PAD Registry

We investigated the prognostic effects of hyperuricemia and high or low body mass index (BMI) in peripheral artery disease (PAD) after endovascular therapy (EVT). Between July 2015-2016, 357 consecutive patients with PAD who underwent EVT were enrolled. Patients were divided into 2 groups: BMI < 25 kg/m² (low BMI) and ≥ 25 kg/m² (high BMI); they were also divided into 2 more groups based on the presence/absence of hyperuricemia. The primary and secondary endpoints were major adverse cardiovascular and limb events (MACLE), and all-cause death at 3 years post-EVT. Patients with hyperuricemia had significantly lower freedom from MACLE than patients without hyperuricemia at 3 years (57.0 vs 71.9%, p = .0068). The overall survival of patients with hyperuricemia was significantly lower than that of patients without hyperuricemia (63.9 vs 81.7%, p = .0012). Patients with hyperuricemia who had low BMI experienced significantly lower freedom from MACLE than those without hyperuricemia who had low BMI (48.2 vs 69.9%, p = .002). The overall survival of patients with hyperuricemia who had low BMI was significantly lower than that of patients without hyperuricemia who had low BMI (55.2 vs 77.1%, p = .003). Patients with hyperuricemia had significantly more MACLE and a lower survival at 3 years than patients without hyperuricemia, even if they had a low BMI.

The impact of an URAT1 polymorphism on the losartan treatment of hypertension and hyperuricemia

BACKGROUND

This study was designed to evaluate the impact of polymorphisms in the urate transporter 1 (URAT1) gene on the uricosuric action of losartan therapy in hypertensive patients suffering from hyperuricemia.

METHODS

A MassARRAY approach was used to detect single nucleotide polymorphism (SNP) loci in the URAT1 and CYP2C9 genes (16 and 2 loci, respectively) in 111 patients with hypertension and hyperuricemia taking losartan and in 121 healthy controls. In addition, we compared serum urate (SUA) levels and other key clinical biochemistry indices between these two patient groups.

RESULTS

We detected significant differences between the two patient groups with respect to age, SUA, urea, creatine, triglycerides, high-density lipoprotein, low-density lipoprotein, and fasting plasma glucose (all p < 0.05). In addition, we found that hypertensive patients with hyperuricemia were more likely to exhibit the rs3825016(C/T) (36.9% vs 21.5%, p = 0.03), and we determined that a 2-week treatment course with losartan was associated with significant decreases in SUA values (p < 0.001).

CONCLUSION

Our findings indicate that the URAT1 rs3825016 polymorphism may influence the uricosuric action of losartan.