Uric Acid in Metabolic and Cerebrovascular Disorders: A Review.

BACKGROUND: Several studies showed a close link between metabolic syndrome (MetS), type 2 diabetes (T2DM) and cerebrovascular diseases. There is considerable debate regarding the role of uric acid (UA) as a risk factor in these conditions. OBJECTIVE: The aim of this narrative review is to discuss the links between UA, MetS, T2DM and cerebrovascular disease. METHODS: An extensive review has been conducted based on the scientific literature published in English, and indexed in MEDLINE (through PubMed), EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and Google Scholar from January to May 2019. Additional relevant studies published after the initial review were also considered during the period of June 2019-October 2019, during which, this manuscript was written. The Mesh Terms considered were: uric acid, antioxidant, oxidant, metabolic syndrome, diabetes, cerebrovascular diseases, stroke, haemorrhagic stroke, neurocognitive disorders, and their combinations. RESULTS: The literature review shows a dose-dependent inflammatory action of UA, which occurs with serum concentrations >4 mg/dl (>0.24 mmol/l), representing one of the contributors to the chronic inflammatory process that underlies metabolic and cerebrovascular diseases. CONCLUSION: UA, which is associated with arterial hypertension and cardiovascular diseases, represents one of the indicators of oxidative homeostasis. Increasing concentrations represent a status of active inflammation which is observed with metabolic and cerebrovascular diseases.

Uric Acid, Metabolic Syndrome and Atherosclerosis: The Chicken or the Egg, Which Comes First?

BACKGROUND: A great debate in literature exists nowadays on the role of uric acid as a marker of cardiovascular and metabolic organ damage or a risk factor for cardiovascular and metabolic disease. METHODS: The study aimed to determine the relationship among serum uric acid and metabolic syndrome and atherosclerosis, by means of carotid intima media-thickness, in a cohort of 811 otherwise healthy overweight/obese subjects, without overt atherosclerosis not using any kind of drug. RESULTS: Uric acid levels were positively related to male gender, waist circumference, BMI, systolic and diastolic pressure levels, fasting insulin, fasting glucose, HOMA-IR, triglycerides, total cholesterol, LDL cholesterol, the presence of metabolic syndrome and the number of the components of metabolic syndrome and negatively related to HDL cholesterol levels. No correlation was found between uric acid and carotid intima media thickness. At the multiple regression analysis, only waist circumference and triglycerides (positively) and HDL-cholesterol (negatively) maintained an independent association with uric acid as dependent variable, while age, female gender and uric acid showed a significant independent association with metabolic syndrome as dependent variable. Moreover, the analysis of the odd ratios showed that the risk of developing metabolic syndrome was consistent with uric acid levels ranging from 3 mg/dl to 8 mg/dl. CONCLUSION: The presence of metabolic syndrome does not seem to provide hyperuricemia. By contrast, higher serum uric acid level may predict the risk of metabolic syndrome. Moreover, our results suggest that uric acid cannot be considered a risk factor for early atherosclerosis, at least when assessed using carotid ultrasound.