Causal impact of human blood metabolites and metabolic pathways on serum uric acid and gout: a mendelian randomization study.

Objective: Hyperuricaemia and gout are common metabolic disorders. However, the causal relationships between blood metabolites and serum urate levels, as well as gout, remain unclear. A systematic evaluation of the causal connections between blood metabolites, hyperuricemia, and gout could enhance early screening and prevention of hyperuricemia and gout in clinical settings, providing novel insights and approaches for clinical treatment. Methods: In this study, we employed a bidirectional two-sample Mendelian randomization analysis utilizing data from a genome-wide association study involving 7,286 participants, encompassing 486 blood metabolites. Serum urate and gout data were sourced from the Chronic Kidney Disease Genetics consortium, including 288,649 participants for serum urate and 9,819 African American and 753,994 European individuals for gout. Initially, LDSC methodology was applied to identify blood metabolites with a genetic relationship to serum urate and gout. Subsequently, inverse-variance weighting was employed as the primary analysis method, with a series of sensitivity and pleiotropy analyses conducted to assess the robustness of the results. Results: Following LDSC, 133 blood metabolites exhibited a potential genetic relationship with serum urate and gout. In the primary Mendelian randomization analysis using inverse-variance weighting, 19 blood metabolites were recognized as potentially influencing serum urate levels and gout. Subsequently, the IVW p-values of potential metabolites were corrected using the false discovery rate method. We find leucine (IVW P FDR = 0.00004), N-acetylornithine (IVW P FDR = 0.0295), N1-methyl-3-pyridone-4-carboxamide (IVW P FDR = 0.0295), and succinyl carnitine (IVW P FDR = 0.00004) were identified as significant risk factors for elevated serum urate levels. Additionally, 1-oleoylglycerol (IVW P FDR = 0.0007) may lead to a substantial increase in the risk of gout. Succinyl carnitine exhibited acceptable weak heterogeneity, and the results for other blood metabolites remained robust after sensitivity, heterogeneity, and pleiotropy testing. We conducted an enrichment analysis on potential blood metabolites, followed by a metabolic pathway analysis revealing four pathways associated with serum urate levels. Conclusion: The identified causal relationships between these metabolites and serum urate and gout offer a novel perspective, providing new mechanistic insights into serum urate levels and gout.

Prevalence and Distribution of Osteopenia in Chinese Population: A System Review and Meta-Analysis.

Background: The number of patients with osteoporosis ranks first in the world in China and as a precursor state of osteoporosis, the number and incidence of osteopenia are much higher than that of osteoporosis. This meta-analysis was conducted to evaluate the incidence and distribution of osteopenia in adults in mainland of China over 10 years to provides reference for the early prevention of osteoporosis and policymaking. Methods: Relevant data were extracted from the databases including CNKI, Wanfang, VIP, Web of Science, PubMed, EMBASE, and Medline about the surveys on osteoporosis and bone loss from 2010 to 2021 by searching. The random effects model was adopted for Meta-analysis, and the funnel plot was used to test publication bias. Results: Forty-seven literatures were included in this study, covering 27 provinces and 38 regions in the mainland of China, with the study of 135,688 cases, showing that the prevalence of osteopenia in adults in the past decade was 28.3%(95% CI 24-33%), aged 40∼60 yr old, reaching the highest level. The incidence of osteopenia in males was higher than that in females (P<0.05), without significant difference in south and north China. Conclusion: There is a large population with osteopenia in China, especially middle-aged population, both men and women should pay attention to osteopenia to delay its further progression.

Lens siderosis resulting from a tiny missed intralenticular foreign body.

We report a patient with clinical ocular siderosis at the time of presentation but undetectable intraocular foreign body on computed tomography (CT) and ultrasonography. A 24-year-old man suffered from right ocular injury when hammering metal on metal. Slit-lamp examination revealed a small corneal perforating wound and an iris hole, but no intraocular foreign body was found under fundus examination. There was also no evidence of intraocular foreign body on ultrasonography and orbital CT scan. About 1 month later, lens siderosis with cataract formation developed, and the patient received lens extraction with intraocular lens implantation. During the operation, a small (< 1 x 1 x 1 mm in size) intralenticular foreign body of metal material was found and removed. The patient's visual acuity improved from 6/20 to 6/6 on the next day. A patient suspected to have intraocular foreign body should be followed-up closely; it is better to remove the foreign body before siderosis bulbi occurs.

Macular hole in Behcet's disease.

Behcet's disease is an inflammatory disorder of unknown cause, characterized by recurrent oral aphthous ulcers, genital ulcers, uveitis, and skin lesions. Ocular involvement occurs in 60-80% of patients with Behcet's disease and presents as panuveitis in most cases. Posterior segment involvement may lead to irreversible alterations and significant vision loss. The development of a partial or full-thickness macular hole, though rarely reported, may cause serious vision loss. In this report, we present two cases of macular hole in the worse eye of bilateral cases of Behcet's disease, and discuss the possible mechanisms and management in such cases.