IM - COMMENTARYUric acid and cardiac performanceEnzo ManzatoReceived: 16 April 2014/Accepted: 3 May 2014/Published online: 28 May 2014? SIMI 2014Uric acid is a molecule at the crossroad of the purine, lipid,and carbohydrate metabolisms [1]. This molecule is theculprit agent of gout, and is considered a risk factor(sometime causal factor) for hypertension, diabetes, renalfunction impairment, and cardiovascular events [2–4]. Thisissue of Internal and Emergency Medicine contains a paperfrom the Brisighella Heart Study by Cicero and co-workers[5] reporting an interesting observation about uric acid andsome markers of myocardial function. The paper showsthat in a sample of subjects, the serum concentrations ofuric acid (not modif i ed by any drugs) are signif i cantlyinversely associated with the estimated cardiac output andcardiac stroke volume. In a stepwise multiple linearregression analysis, the other factors signif i cantly associ-ated with these two cardiac markers are mean arterialpressure, heart rate, and age.The sample population, even though rather limited forthis type of study and for the cardiac parameters evaluatedhere, is well selected, and this selection adds value to theresults. At f i rst glance, the linear relations between serumuric acid and the cardiac output/stroke volume mightappear limited, but the multiple regression analysis con-f i rms a role for uric acid in this association.As it is well discussed in the paper, uric acid has alsobeen implicated in the pathogenesis of heart failure, andthese results conf i rm a role for this acid in cardiac per-formance. However, a def i nite demonstration that byreducing serum uric acid there is an improvement in theprognosis of cardiac patients is still lacking [6].This paper, along with many others, uses serum uric acidconcentrations for the evaluation of the activity of animportant enzyme, i.e. xanthine oxidase, the enzyme that inhumans regulates uric acid production from purines.Unfortunately, the serum uric acid concentrations areaffected by many other different factors, including diet,renal function, insulin resistance, and uric acid excretion[7]. The uric acid production and excretion (intestinal andrenal) are regulated by many different genes, with differentimportances in determining the serum concentrations ofuric acid [8]. Moreover, each gene can be modif i ed indifferent ways so that the effect of serum uric acid con-centrations on the genetic background can vary from verylimited variations to severe and devastating illnesses. Somegenetic variants affecting serum uric acid concentrationsare also associated with obesity and metabolic syndrome[9].All these considerations do not impair the relevance ofthe results reported by Cicero et al. but on the contrary,highlight the need for further research about uric acid andcardiac performance, about the role of xanthine oxidase inhealth and diseases, and about the effects of the geneticbackground on purine metabolism.Conf l ict of interest None.References1. Johnson RJ, Nakagawa T, Sanchez-Lozada LG, Shaf i u M,Sundaram S, Le M et al (2013) Sugar, uric acid, and the etiologyof diabetes and obesity. Diabetes 62:3307–3315This comment refers to the article available atdoi:10.1007/s11739-013-1016-9.E. Manzato (&)Department of Medicine, University of Padua, Padua, Italye-mail: enzo.manzato@unipd.it123Intern Emerg Med (2014) 9:613–614DOI 10.1007/s11739-014-1082-7
