High Level of Serum Uric Acid induced Monocyte Inflammation is Related to Coronary Calcium Deposition in the Middle-Aged and Elder Population of China: A five-year Prospective Cohort Study

Hyperuricemia Increases the Risk of Postoperative Recurrence in Chinese Patients with Chronic Rhinosinusitis

Background

Elevated serum uric acid is crucial in the pathophysiology of chronic inflammatory diseases. However, its impact on chronic rhinosinusitis (CRS) recurrence risk is unknown. This study investigates the association between elevated serum uric acid and the risk of CRS recurrence.

Methods

A retrospective cohort study was conducted on 1004 CRS patients (including 638 males and 366 females) who received functional endoscopic sinus surgery. All patients were followed up for more than 2 years, and categorized into subgroups based on phenotype, gender, and postoperative recurrence. Cox regression analysis was performed to evaluate the associations between serum uric acid and the risk of CRS recurrence.

Results

After categorization, 104 males had hyperuricemia, and 54 females presented hyperuricemia. The rate of recurrent CRS in the hyperuricemia group was significantly higher compared to the non-hyperuricemia group in both males and females (P<0.05). In both male and female patients, the rate of hyperuricemia and uric acid levels were elevated in the recurrent CRS group in comparison with the non-recurrent CRS group (P<0.05). Unadjusted and adjusted Cox regression analysis demonstrated that serum uric acid was an independent risk factor for CRS recurrence (P<0.05). The receiver operator characteristic curve showed that serum uric acid was a potential biomarker for predicting the recurrence of CRS and its phenotypes in both genders (P<0.05).

Conclusion

There is a close relationship between elevated serum uric acid and the recurrence risk of CRS and its phenotypes, suggesting that serum uric acid may be a novel biomarker for predicting recurrent CRS.

Correlation of serum VEGF-C, ANGPTL4, and activin A levels with frailty

BACKGROUND

Secretory factors linked to lymphogenesis, such as vascular endothelial growth factor C (VEGF-C), angiopoietin like protein 4 (ANGPTL4), and activin A (ACV-A), have been recognized as potential markers of chronic inflammatory status and age-related diseases. Furthermore, these factors may also be linked to frailty. The primary objective of this study was to examine the serum VEGF-C, ANGPTL4, and ACV-A levels in young individuals, healthy older individuals, and older individuals with pre-frailty and frailty, and to determine their association with pro-inflammatory factor levels.

METHODS

We conducted an observational study, enrolling a total of 210 older individuals and 20 young healthy volunteers. Participants were divided into four groups based on the Freid frailty phenotype: healthy young group, older patients without frailty group, pre-frail older group, and frail older group. Plasma and peripheral blood mononuclear cells (PBMCs) were collected from all four groups. ELISA was used to measure the serum levels of VEGF-C, ANGPTL4, ACV-A, and pro-inflammatory cytokines, while RT-qPCR was used to measure the transcription level of VEGF-C, ANGPTL4 and ACV-A in PBMCs.

RESULTS

In comparison to healthy young individuals and older participants without frailty, older participants with frailty exhibited lower renal function, higher serum levels and transcription levels of VEGF-C, ANGPTL4, ACV-A, and elevated levels of pro-inflammatory cytokines (CRP, IL-1β, and TNF-α). Multiple linear regression analysis revealed that serum levels of VEGF-C, ANGPTL4, and ACV-A were positively correlated with the frailty index, independent of age, eGFR, and comorbidities. Furthermore, the receiver operating characteristic (ROC) curve analysis demonstrated that serum levels of VEGF-C, ANGPTL4, and ACV-A have great accuracy in predicting frailty.

CONCLUSION

Elevated serum levels of VEGF-C, ANGPTL4, and ACV-A are associated with frailty status.

The Role of Uric Acid in Human Health: Insights from the Uricase Gene

Uric acid is the final product of purine metabolism and is converted to allantoin in most mammals via the uricase enzyme. The accumulation of loss of function mutations in the uricase gene rendered hominoids (apes and humans) to have higher urate concentrations compared to other mammals. The loss of human uricase activity may have allowed humans to survive environmental stressors, evolution bottlenecks, and life-threatening pathogens. While high urate levels may contribute to developing gout and cardiometabolic disorders such as hypertension and insulin resistance, low urate levels may increase the risk for neurodegenerative diseases. The double-edged sword effect of uric acid has resurrected a growing interest in urate's antioxidant role and the uricase enzyme's role in modulating the risk of obesity. Characterizing both the effect of uric acid levels and the uricase enzyme in different animal models may provide new insights into the potential therapeutic benefits of uric acid and novel uricase-based therapy.

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.

The potential relationship of coronary artery disease and hyperuricemia: A cardiometabolic risk factor

Coronary arterial disease (CAD) is the leading cause of mortality in the world. Hyperuricemia has recently emerged as a novel independent risk factor of CAD, in addition to the traditional risk factors such as hyperlipidemia, smoking, and obesity. Several clinical studies have shown that hyperuricemia is strongly associated with the risk, progression and poor prognosis of CAD, as well as verifying an association with traditional CAD risk factors. Uric acid or enzymes in the uric acid production pathway are associated with inflammation, oxidative stress, regulation of multiple signaling pathways and the renin-angiotensin-aldosterone system (RAAS), and these pathophysiological alterations are currently the main mechanisms of coronary atherosclerosis formation. The risk of death from CAD can be effectively reduced by the uric acid-lowering therapy, but the interventional treatment of uric acid levels in patients with CAD remains controversial due to the diversity of co-morbidities and the complexity of causative factors. In this review, we analyze the association between hyperuricemia and CAD, elucidate the possible mechanisms by which uric acid induces or exacerbates CAD, and discuss the benefits and drawbacks of uric acid-lowering therapy. This review could provide theoretical references for the prevention and management of hyperuricemia-associated CAD.

Recent Insights Into the Role of Macrophages in Acute Gout

Gout is a common type of inflammatory arthritis characterized by the presence of monosodium urate crystals (MSU) in the joints. Macrophages are believed to be involved in gout flares. It has long been recognized that resident macrophage and monocyte derived macrophages are distinct subsets and there have been attempts to investigate their roles in acute gout, respectively. Previous studies revealed that resident macrophages initiate and drive the inflammation, while monocyte derived macrophages differentiated into M1-like macrophages in response to MSU crystals. With the advancement of technologies, subpopulations of synovial resident macrophages have been defined with the characteristics more accurately described. Resident macrophages in the synovial lining layer showed an anti-inflammatory effect in rheumatoid arthritis, but specific Trpv4 depletion of them reduced MSU crystals induced murine arthritis. CD14+ monocytes in the synovial fluid from patients with gout exhibit phenotypes of anti-inflammatory as well as pro-inflammatory characteristics. Here, we review the main aspects of macrophages in the initiation and resolution of acute gout and try to clarify the specific role of each subpopulation. Building a reliable diagram of the effect of monocytes and macrophages during MSU crystals induced arthritis will bring us closer to targeting macrophages for improving the management of gout.