Association of serum uric acid levels with the incident of kidney disease and rapid eGFR decline in Chinese individuals with eGFR > 60 mL/min/1.73 m2 and negative proteinuria

Is there a relationship between serum uric acid and prostate-specific antigen in middle-aged and elderly Chinese men?

Hyperuricemia may be one of the risk factors for the development of prostate cancer. We evaluated the association between serum uric acid (SUA) and elevated prostate-specific antigen (PSA) in the middle-aged and elderly Chinese men, and the adjustment effects of age, glycolipid metabolism and renal function. From January 2019 to December 2024, 967 participants from the middle-aged and elderly Chinese men who attended the urology outpatient clinic of Shuguang Hospital (Shanghai, China) were recruited in this cross-sectional study. Blood samples from participants were collected for the determinations of SUA, PSA, fasting blood glucose, total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, creatinine, blood urea nitrogen and glomerular filtration rate. After adjusting for age, glycolipid metabolism and renal function, the odds ratios (95% confidence interval) of elevated PSA across increasing quartiles of SUA were 1.00, 1.42 (0.97-2.08), 1.45 (0.98-2.13) and 1.26 (0.83-1.90), respectively (P for trend = 0.259). The regression spline showed that the risk of elevated PSA tended to a slow but linear increase for SUA levels greater than about 443 μmol/L (P for non-linearity = 0.431). The stratified analyses suggested that the associations were significant for participants at least 75 years (P for trend = 0.015), but not for those less than 68 (P for trend = 0.162) and 68-74 years (P for trend = 0.761). Moreover, HDL-C was significantly interacted with SUA (P for interaction = 0.046). The associations were more evident in participants with high HDL-C levels (P for trend = 0.007) than in those with low (P for trend = 0.943) and median HDL-C levels (P for trend = 0.176). Our study for the first time demonstrates that SUA levels are unlikely to be associated with the risk of elevated PSA in the middle-aged and elderly Chinese men. Yet the associations between SUA and elevated PSA could be significant for participants at least 75 years. Notably, HDL-C may modify the associations.

Machine learning-based prediction models for renal impairment in Chinese adults with hyperuricaemia: risk factor analysis

In hyperuricaemic populations, multiple factors may contribute to impaired renal function. This study aimed to establish a machine learning-based model to identify characteristic factors related to renal impairment in hyperuricaemic patients, determine dose‒response relationships, and facilitate early intervention strategies. Data were collected through the big data platform of Nanjing Hospital of Traditional Chinese Medicine, encompassing 2,705 patients with hyperuricaemia (1,577 with renal impairment, 828 without) from June 2019 to June 2022. After multiple imputations for missing values, the dataset was randomly split into training (70%) and validation (30%) sets. We employed three machine learning algorithms for feature selection: random forest (with 100 decision trees and an OOB error rate of 23.34%), LASSO regression (optimal lambda of -3.58), and XGBoost (learning rate of 0.3, maximum tree depth of 1, and 50 rounds of boosting). The intersection of features identified by these algorithms through Venn diagram analysis yielded four key predictors. A logistic regression model was subsequently constructed and evaluated for discrimination (AUC), calibration (Brier score), and clinical utility (DCA). Restricted cubic spline (RCS) curves were utilized to analyse the dose‒response relationships. The model, which incorporates age, cystatin C (Cys-C), uric acid (UA), and sex, demonstrated robust performance, with an AUC of 0.818 [95% CI (0.796-0.817)] in the training set and an AUC of 0.82 [95% CI (0.787-0.853)] in the validation set. Calibration tests yielded Brier scores of 0.160 and 0.158, respectively. Clinical decision curves revealed optimal prediction probability intervals of 6-99.02% and 7-93.14%. In the hyperuricaemic population, each 0.5 mg/L increase in Cys-C, 10-year increase in age, and 100 µmol/L increase in UA corresponded to increased risks of 13%, 81%, and 73%, respectively. RCS analysis revealed nonlinear relationships for Age and Cys-C and a linear relationship for UA, with sex-specific distribution patterns. The machine learning-based model incorporating these four indicators demonstrated excellent predictive performance for renal impairment in hyperuricaemic patients. These findings suggest that monitoring Cys-C and UA levels while considering age and sex differences is crucial for risk assessment and prevention strategies.

Detection of decline in estimated glomerular filtration rate in patients with type 2 diabetes by cystatin C-based equations

BACKGROUND

Aging population is a significant issue in Viet Nam and across the globe. Elderly individuals are at higher risk of chronic kidney disease (CKD), especially those with diabetes. Several studies found that the estimated glomerular filtration rate (eGFR) determined using creatinine-based equations was not as accurate as that determined using cystatin C-based equations. Cystatin C-based equations may be beneficial in elderly patients with an age-associated decline in kidney function. Early determination of eGFR decline and associated factors would aid in appropriate interventions to improve kidney function in elderly patients with diabetes.

AIM

To determine the utility of cystatin C-based equations in early detection of eGFR decline and to explore factors associated with eGFR decline in elderly patients with diabetes.

METHODS

This cross-sectional study included 93 participants aged ≥ 60 years evaluated in Can Tho University of Medicine and Pharmacy Hospital between October 2022 and July 2023, including 47 and 46 participants with and without diabetes respectively, according to the American Diabetes Association criteria for diabetes. The kappa coefficient, Student's t, Mann-Whitney, χ 2, Pearson's correlation, multivariate logistic regression, and multiple linear regression analyses were employed.

RESULTS

The eGFRs were lower with the cystatin C-based equations than with the creatinine-based equations. Good agreement was found between the Modification of Diet in Renal Disease (MDRD) and CKD Epidemiology Collaboration (CKD-EPI) 2021 creatinine-cystatin C equations (kappa = 0.66). In the diabetes group, 30% of the participants had low eGFR. Both plasma glucose and glycated hemoglobin were associated with an increased risk of eGFR decline (P < 0.05) and negatively correlated with eGFR (P = 0.001). By multivariate logistic regression, total cholesterol, and exercise were independently associated with low eGFR. By multiple linear regression, higher plasma glucose levels were correlated with lower eGFR (P = 0.026, r = -0.366).

CONCLUSION

Cystatin C-based equations were superior in the early detection of a decline in eGFR, and the MDRD equation may be considered as an alternative to the CKD-EPI 2021 creatinine-cystatin C equation. Exercise, plasma glucose, and total cholesterol were independently associated with eGFR in patients with diabetes.

Correlation Between Uric Acid/High Density Lipoprotein Cholesterol Ratio and Postoperative AKI in Patients with CABG

Objective

This study aims to investigate the association between preoperative serum uric acid to high-density lipoprotein cholesterol ratio (UHR) and the occurrence of postoperative acute kidney injury (AKI) in patients who underwent coronary artery bypass grafting (CABG).

Methods

A prospective observational study was conducted at Fujian Heart Medical Center between May 2022 and December 2023, recruiting patients scheduled for CABG. Participants were categorized into two groups based on AKI occurrence post-surgery. Univariate and multivariate logistic regression analyses were performed to identify predictor variables for AKI after CABG. A nomogram was constructed based on these predictors, and its calibration was evaluated using the receiver operating characteristic curve (ROC) and Hosmer-Lemeshow goodness of fit test. The diagnostic value of UHR in AKI after CABG was explored using the area under the curve (AUC).

Results

The study included 301 CABG patients, of whom 72 (23.92%) developed AKI. After adjusting for age, gender, body mass index, and extracorporeal circulation, binary logistic regression analysis revealed that a higher UHR value was an independent risk factor for developing AKI after CABG (OR=7.410, 95% CI: 3.829-14.855), P <0.05. The prediction nomogram demonstrated excellent discriminability, with an AUC of 0.87 and good calibration (Hosmer-Lemeshow test, P <0.05). Compared with other clinical indicators, ROC analysis indicated that UHR had the largest AUC (0.821), corresponding to 70.8% sensitivity and 79.0% specificity.

Conclusion

Higher UHR was associated with an increased risk of AKI after CABG and may serve as a prospective biomarker for predicting AKI.

Early onset of hyperuricemia is associated with the risk of nonalcoholic fatty liver disease across life course

BACKGROUND AND AIM

Hyperuricemia is associated with nonalcoholic fatty liver disease (NAFLD), whereas whether the association differed by hyperuricemia onset age remained unclear. This study sought to investigate the associations of hyperuricemia onset age with the risk of incident NAFLD across adulthood.

METHODS AND RESULTS

Based on Kailuan prospective cohort, our analysis comprised 3318 new-onset hyperuricemia cases from 2006 to 2015 and 3318 age- and sex-matched controls who were randomly selected from the general population. The risk of NAFLD across the onset age groups (<45, 45-54, 55-64, and ≥65 years) were compared using multivariable-adjusted Cox regression models. During a median follow-up of 6.78 years, 744 (22.42%) hyperuricemia participants and 586 (17.66%) normouricemia participants were diagnosed with incident NAFLD. After adjusted for potential confounders, the risk of NAFLD was gradually attenuated with each decade increase in hyperuricemia onset age. The adjusted hazard ratio (95% confidence interval) was 1.62 (1.33-1.97) for hyperuricemia onset age <45 years, 1.26 (1.01-1.57) for age of 45-54 years, 1.24 (1.00-1.59) for age of 55-64 years, and 1.19 (0.90-1.71) for age ≥65 years, respectively. The trend remained robust among the multiple sensitivity analyses.

CONCLUSIONS

The relative risk of incident NAFLD differed across hyperuricemia onset age-group, and the association was more evident in those with a younger age of hyperuricemia onset, highlighting the importance of performing early strategies on the prevention of NAFLD.

Age-specific Multimorbidity Patterns and Burden on All-Cause Mortality and Public Direct Medical Expenditure: A Retrospective Cohort Study

OBJECTIVE

To evaluate age-specific multimorbidity patterns and morbidity burden on mortality and healthcare expenditure across age groups.

PATIENTS AND METHODS

Retrospective observational study between January 1, 2009 to December 31, 2017 using electronic health records in Hong Kong: Individuals were stratified by age (< 50, 50-64, 65-79, ≥ 80), and sub-classified by number of morbidities (0, 1, 2, 3, ≥ 4) out of 21 common chronic conditions. Clustering analyses were conducted to identify specific patterns of multimorbidity. Association between the number as well as combinations of morbidities and all-cause mortality and public expenditure was examined.

RESULTS

4,562,832 individuals with a median follow-up of 7 years were included. Mental disorders were the top morbidities among young individuals, while cardiovascular diseases were prevalent in the elderly. An increased number of morbidities was associated with a greater relative risk for mortality and medical expenditure, and this relationship was stronger among younger patients. Compared to individuals in the same age group without morbidity, the hazard ratios (HR; 95% CI) of all-cause mortality in patients aged < 50 and ≥ 80 with two comorbidities 3.81 (3.60-4.03) and 1.38 (1.36-1.40), respectively, which increased to 14.22 (9.87-20.47) and 2.20 (2.13-2.26), respectively, as the number of morbidities increased to ≥ 4. The stroke-hypertension cluster was shown to be associated with the highest HR of mortality 2.48 (2.43-2.53) among all identified clusters arising from the clustering analysis.

CONCLUSION

Given the stronger association between multimorbidity and all-cause mortality and greater opportunity costs in younger populations, prevention and management of early-onset multimorbidity are warranted. (248 words).

Gasdermin D promotes hyperuricemia-induced renal tubular injury through RIG-I/caspase-1 pathway

Renal tubular epithelial cells injury is one of the most important pathological features in hyperuricemic nephropathy (HN). However, the involvement of gasdermin D (GSDMD)-mediated pyroptosis in HN remains obscure. We found GSDMD was upregulated in the kidney tissue of HN mice, which was accompanied by the loss of renal function, renal tubular fibrosis, and reduced body weight. These changes in HN mice were inhibited by GSDMD knockout. Knockdown of GSDMD inhibited the high uric acid-induced injury in cultured cells (NRK-52E). Mechanistically, co-immunoprecipitation showed that RIG-I exist in a complex with caspase-1. Overexpression of RIG-I induced increased expression of caspase-1 protein and caspase-1 activity. Caspase-1 interference significantly reduced the increase of caspase-1 activity and IL-1β production caused by RIG-I overexpression. Knockdown of RIG-I or caspase-1 decreased high uric acid-induced injury in NRK-52E. This work illustrates that targeting the RIG-I/caspase-1/GSDMD may provide potential therapeutic benefits to HN.

Serum uric acid levels in kidney transplant recipients: A cause for concern? A review of recent literature

The impact of elevated serum uric acid levels i.e., hyperuricemia, on native and transplant chronic kidney disease progression has been debated. This literature review presents an analysis of multiple studies exploring the relationship between serum uric acid levels and kidney transplant outcomes. The review includes a summary of the pathophysiology of hyperuricemia and gout, a review of urate-lowering therapies, and an appraisal of multiple studies examining the association or lack thereof between serum uric acid level and kidney transplant outcomes. Based on these studies, elevated serum uric acid levels may contribute to CKD progression in kidney transplant recipients. In this review, we also summarize current literature to highlight risk factors associated with hyperuricemia as well as the need for further investigation to monitor and manage hyperuricemia in kidney transplant recipients.

Cytoprotective remedies for ameliorating nephrotoxicity induced by renal oxidative stress

AIMS

Nephrotoxicity is the hallmark of anti-neoplastic drug metabolism that causes oxidative stress. External chemical agents and prescription drugs release copious amounts of free radicals originating from molecular oxidation and unless sustainably scavenged, they stimulate membrane lipid peroxidation and disruption of the host antioxidant mechanisms. This review aims to provide a comprehensive collection of potential cytoprotective remedies in surmounting the most difficult aspect of cancer therapy as well as preventing renal oxidative stress by other means.

MATERIALS AND METHODS

Over 400 published research and review articles spanning several decades were scrutinised to obtain the relevant data which is presented in 3 categories; sources, mechanisms, and mitigation of renal oxidative stress.

KEY-FINDINGS

Drug and chemical-induced nephrotoxicity commonly manifests as chronic or acute kidney disease, nephritis, nephrotic syndrome, and nephrosis. Renal replacement therapy requirements and mortalities from end-stage renal disease are set to rapidly increase in the next decade for which 43 different cytoprotective compounds which have the capability to suppress experimental nephrotoxicity are described.

SIGNIFICANCE

The renal system performs essential homeostatic functions that play a significant role in eliminating toxicants, and its accumulation and recurrence in nephric tissues results in tubular degeneration and subsequent renal impairment. Global statistics of the latest chronic kidney disease prevalence is 13.4 % while the end-stage kidney disease requiring renal replacement therapy is 4-7 million per annum. The remedial compounds discussed herein had proven efficacy against nephrotoxicity manifested consequent to impaired antioxidant mechanisms in preclinical models produced by renal oxidative stress activators.

Age-specific associations between the number of co-morbidities, all-cause mortality and public direct medical costs in patients with type 2 diabetes: A retrospective cohort study

AIM

To evaluate the association between the number of co-morbidities, all-cause mortality and public health system expenditure in patients with type 2 diabetes (T2D) across different age groups.

MATERIALS AND METHODS

A retrospective observational study of T2D patients using electronic health records in Hong Kong was conducted. Patients were stratified by age (< 50, 50-64, 65-79, ≥ 80 years) and the number of co-morbidities (0, 1, 2, 3, ≥ 4), defined using the Charlson Comorbidity Index and prevalent chronic diseases identified in local surveys. The association between the number of co-morbidities, all-cause mortality and direct medical costs was examined using Cox proportional hazard regression and the gamma generalized linear model with log link function.

RESULTS

A total of 262 212 T2D patients with a median follow-up of 10 years were included. Hypertension and dyslipidaemia were the most common co-morbidities in all age groups. After age stratification, cardiovascular diseases dominated the top pair of co-morbidities in the older age groups (65-79 and ≥ 80 years), while inflammatory and liver disease were predominant among younger individuals. Compared with co-morbidity-free T2D patients, the hazard ratios (95% CI) of death for patients aged younger than 50 and 80 years or older with two co-morbidities were 1.31 (1.08-1.59) and 1.25 (1.15-1.36), respectively, and increased to 3.08 (2.25-4.21) and 1.98 (1.82-2.16), respectively, as the number of co-morbidities increased to four or more. Similar trends were observed for medical costs.

CONCLUSIONS

Age-specific co-morbidity patterns were observed for patients with T2D. A greater number of co-morbidities was associated with increased mortality and healthcare costs, with stronger relationships observed among younger patients.

The biomarkers discovery of hyperuricemia and gout: proteomics and metabolomics

Background

Hyperuricemia and gout are a group of disorders of purine metabolism. In recent years, the incidence of hyperuricemia and gout has been increasing, which is a severe threat to people's health. Several studies on hyperuricemia and gout in proteomics and metabolomics have been conducted recently. Some literature has identified biomarkers that distinguish asymptomatic hyperuricemia from acute gout or remission of gout. We summarize the physiological processes in which these biomarkers may be involved and their role in disease progression.

Methodology

We used professional databases including PubMed, Web of Science to conduct the literature review. This review addresses the current landscape of hyperuricemia and gout biomarkers with a focus on proteomics and metabolomics.

Results

Proteomic methods are used to identify differentially expressed proteins to find specific biomarkers. These findings may be suggestive for the diagnosis and treatment of hyperuricemia and gout to explore the disease pathogenesis. The identified biomarkers may be mediators of the link between hyperuricemia, gout and kidney disease, metabolic syndrome, diabetes and hypertriglyceridemia. Metabolomics reveals the main influential pathways through small molecule metabolites, such as amino acid metabolism, lipid metabolism, or other characteristic metabolic pathways. These studies have contributed to the discovery of Chinese medicine. Some traditional Chinese medicine compounds can improve the metabolic disorders of the disease.

Conclusions

We suggest some possible relationships of potential biomarkers with inflammatory episodes, complement activation, and metabolic pathways. These biomarkers are able to distinguish between different stages of disease development. However, there are relatively few proteomic as well as metabolomic studies on hyperuricemia and gout, and some experiments are only primary screening tests, which need further in-depth study.

Lipidomics analysis facilitate insight into the molecular mechanisms of urate nephropathy in a gout model induced by combination of MSU crystals injection and high-fat diet feeding

Renal injury is one of the most common clinical manifestations of patients with hyperuricaemia/gout. The precise pathophysiological mechanism(s) for the renal injury is still unknown. Furthermore, it is also unclear whether the clinical therapies (e.g., colchicine and febuxostat) could prevent its progression or not. Lipids are involved in almost all of important biological processes and play critical roles in maintaining the renal functions. Herein, shotgun lipidomics was performed for class-targeted lipid analysis of cellular lipidomes in renal tissue of a gouty model induced by combination of monosodium urate crystals injection and high-fat diet feeding with/without treatment with either colchicine or febuxostat. Serum uric acid (UA), proinflammatory cytokines (i.e., TNF-α and IL-6), xanthine oxidase activity, footpad swelling, and pain threshold were determined to evaluate the gouty severity. Renal histopathological changes, blood urea nitrogen, creatinine, and kidney index were used to reflect renal injury. Lipidomics analysis revealed that altered triacylglycerol (TAG) profile, impaired mitochondrial function resulted by decreased tetra 18:2 cardiolipin, reduced 4-hydroxyalkenal (HNE) species, and elevated lysophospholipids were already present in the kidneys at early stage of renal injury, probably contributing to its occurrence and development. In addition to significantly reduce the UA level and relief the gouty severity, treatment with either colchicine or febuxostat could restore HNE bioavailability, thereby delaying the progression of renal injury. However, both of them could not recover the altered TAG profile and the impaired mitochondrial function, indicating that treatment with either of them could not completely prevent the development of renal injury in the gouty model.

Associations of Liver Function Parameters with New-Onset Hyperuricemia in a Large Taiwanese Population Study

Hyperuricemia is the chief cause of gout and has been linked with hypertension, cardiovascular and renal disease, diabetes and metabolic syndrome. Liver with the highest protein expression of xanthine oxidase, the main enzyme responsible for uric acid formation, is the primary site of uric acid biosynthesis. However, there are few studies that examine the association between liver function and new-onset hyperuricemia. Hence, using the Taiwan Biobank dataset, we aimed to explore the capability of liver function parameters, including gamma-glutamyl transferase, total bilirubin, albumin, alanine aminotransferase and aspartate aminotransferase in association with the subsequent development of hyperuricemia. We analyzed 21,030 participants without hyperuricemia at baseline. Hyperuricemia was defined as a uric acid concentration > 6.0 mg/dL in women or >7.0 mg/dL in men. New-onset hyperuricemia was defined as participants without baseline hyperuricemia having developed hyperuricemia upon subsequent exam. Overall, 1804 (8.6%) of the study subjects developed new-onset hyperuricemia. After multivariable analysis, significant associations were found between the male sex (odds ratio [OR], 4.412; p < 0.001), high values of systolic blood pressure (SBP) (OR, 1.006; p = 0.012), body mass index (BMI) (OR, 1.064; p < 0.001), fasting glucose (OR, 1.005; p < 0.001), triglycerides (OR, 1.001; p = 0.003), uric acid (OR, 5.120; p < 0.001), low values of estimated glomerular filtration rates (eGFR) (OR, 0.995; p < 0.001), total bilirubin (OR, 0.616; p < 0.001) and new-onset hyperuricemia. The cutoff level of total bilirubin, according to the Youden index, of receiver operating characteristic curve for identifying new-onset hyperuricemia was 0.65 mg/dL. Low total bilirubin was defined as ≤0.65 mg/dL. After multivariable analysis, we found a significant association between low total bilirubin level (≤0.65 mg/dL) (OR = 0.806; p < 0.001) and new-onset hyperuricemia. Our present study demonstrated that in addition to male sex, high SBP, BMI, fasting glucose, triglycerides, and uric acid and low eGFR, the serum’s total bilirubin levels were negatively associated with new-onset hyperuricemia in a large Taiwanese cohort.

Jian Pi Shen Shi formula alleviates hyperuricemia and related renal fibrosis in uricase-deficient rats via suppression of the collagen-binding pathway

AIM

Jian Pi Shen Shi Formula (JPSSF) is a beneficial treatment for hyperuricemia and related tissue damage in the clinical setting. This study was designed to investigate its therapeutic potential and underlying mechanisms in uricase-deficient rats (Uox^-/- rats).

METHODS

Uox^-/- rats were used to assess the therapeutic potential of JPSSF on hyperuricemia. Protein extracts from renal tissues of a Uox^-/- group and a JPSSF group were analyzed using tandem mass tag labeling quantitative proteomic workflow. Collagen deposition in Uox^-/- rat kidneys was analyzed by Masson trichromatic staining. The gene expression associated with collagen-binding-related signaling pathways in the kidneys was further explored using quantitative polymerase chain reaction assay. The protein expressions of collagen 1a1 (col1a1), col6a1, and α-smooth muscle actin were measured by Western blotting and immunohistochemistry.

RESULTS

JPSSF significantly decreased renal function indices and alleviated renal injuries. The action of JPSSF was manifested by down-regulation of col6a1 and interleukin-1 receptor-associated kinase-like 2, which blocked the binding sites on collagen and further prevented kidney injury. The anti-renal fibrosis effect of JPSSF was confirmed by reducing the collagen deposition and hydroxyproline concentrations. JPSSF treatment also intensely down-regulated the mRNA and protein expressions of col6a1, col1a1, and α-smooth muscle actin, which inhibited the function of the collagen-binding-related signaling pathway.

CONCLUSION

Our results indicated that JPSSF notably ameliorated hyperuricemia and related renal fibrosis in Uox^-/- rats through lowering uric acid and down-regulating the function of the collagen-binding pathway. This suggested that JPSSF is a potential empirical formula for treating hyperuricemia and accompanying renal fibrosis.

Effects of Dietary Macleaya cordata Extract on Growth Performance, Biochemical Indices, and Intestinal Microbiota of Yellow-Feathered Broilers Subjected to Chronic Heat Stress

This study investigated the effect of dietary Macleaya cordata extract (MCE) supplementation on the growth performance, serum parameters, and intestinal microbiota of yellow-feather broilers under heat stress. A total of 216 yellow-feather broilers (28-days-old) were randomly allotted into three groups. A control group (CON) (24 ± 2 °C) and heat stress group (HS) (35 ± 2 °C) received a basal diet, and heat-stressed plus MCE groups (HS-MCE) (35 ± 2 °C) were fed the basal diet with 1000 mg/kg MCE for 14 consecutive days. The results revealed that MCE supplementation improved the final body weight, average daily feed intake, average daily gain, and spleen index when compared with the HS group (p < 0.05). In addition, MCE supplementation decreased (p < 0.05) the activities of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and creatinine, and increased (p < 0.05) the glucose level and alkaline phosphatase activity in heat-stressed yellow-feathered broilers. Moreover, MCE treatment alleviated heat-stress-induced intestinal flora disturbances, decreased the Bacteroidota and Bacteroides relative abundances, and increased Firmicutes. A linear discriminant analysis effect size analysis found five differentially abundant taxa in the HS-MCE group, including Alistipes, Rikenellaceae, Mogibacterium, Butyrivibrio, and Lachnospira. These results suggest that MCE can alleviate HS-induced decline in growth performance by modulating blood biochemical markers and cecal flora composition in broilers.

Developing and validating a prognostic prediction model for patients with chronic kidney disease stages 3-5 based on disease conditions and intervention methods: a retrospective cohort study in China

OBJECTIVES

To develop and validate a nomogram model to predict chronic kidney disease (CKD) stages 3-5 prognosis.

DESIGN

A retrospective cohort study. We used univariate and multivariate Cox regression analysis to select the relevant predictors. To select the best model, we evaluated the prediction models' accuracy by concordance index (C-index), calibration curve, net reclassification index (NRI) and integrated discrimination improvement (IDI). We evaluated the clinical utility by decision curve analysis.

SETTING

Chronic Disease Management (CDM) Clinic in the Nephrology Department at the Guangdong Provincial Hospital of Chinese Medicine.

PARTICIPANTS

Patients with CKD stages 3-5 in the derivation and validation cohorts were 459 and 326, respectively.

PRIMARY OUTCOME MEASURE

Renal replacement therapy (haemodialysis, peritoneal dialysis, renal transplantation) or death.

RESULTS

We built four models. Age, estimated glomerular filtration rate and urine protein constituted the most basic model A. Haemoglobin, serum uric acid, cardiovascular disease, primary disease, CDM adherence and predictors in model A constituted model B. Oral medications and predictors in model A constituted model C. All the predictors constituted model D. Model B performed well in both discrimination and calibration (C-index: derivation cohort: 0.881, validation cohort: 0.886). Compared with model A, model B showed significant improvement in the net reclassification and integrated discrimination (model A vs model B: NRI: 1 year: 0.339 (-0.011 to 0.672) and 2 years: 0.314 (0.079 to 0.574); IDI: 1 year: 0.066 (0.010 to 0.127), p<0.001 and 2 years: 0.063 (0.008 to 0.106), p<0.001). There was no significant improvement between NRI and IDI among models B, C and D. Therefore, we selected model B as the optimal model.

CONCLUSIONS

We constructed a prediction model to predict the prognosis of patients with CKD stages 3-5 in the first and second year. Applying this model to clinical practice may guide clinical decision-making. Also, this model needs to be externally validated in the future.

TRIAL REGISTRATION NUMBER

ChiCTR1900024633 (http://www.chictr.org.cn).

R. S, Toh CC, Sundram M, Md Yusoff NA, Nagappan P, Kamaruzaman S, Yeoh WS, Ong TA, Lim J. Cardiovascular risk factors, ethnicity and infection stone are independent factors associated with reduced renal function in renal stone formers

BACKGROUND

Recent evidence suggested the link between nephrolithiasis and renal function impairment. We aimed to determine the renal function profile and potential factors associated with reduced renal function amongst renal stone formers in multi-ethnic Asians.

METHODS

We conducted a cross-sectional study involving patients undergoing percutaneous nephrolithotomy between May 2015 and December 2019. Reduced renal function was defined as having estimated glomerular filtration rate < 60 ml/min per 1.73 m2. Renal stone samples were collected and quantified using infrared spectroscopy. Potential factors associated with reduced renal function including age, ethnicity, educational level, history of diabetes, hypertension, gout, hydronephrosis, serum uric acid level, and type of renal stone were evaluated using univariable and multivariable analyses.

RESULTS

A total of 1162 patients from a multi-ethnic population (Malays 67%, Chinese 19%, Indians 13% and indigenous people 1%) with median age of 57 years (Interquartile range 48-64) were enrolled in the study. Almost a third of patients were found with reduced renal function. Multivariable analysis showed that the odds of having reduced renal function increased with age, ethnicity, lower educational level, history of diabetes, hypertension, gout, bilateral hydronephrosis, elevated serum uric acid level and infection stone.

CONCLUSIONS

Reduced renal function varies between ethnicities and all age groups of renal stone formers. In addition to age and ethnicity, cardiovascular risk factors including diabetes and hypertension may also need to be taken into account in managing stone patients with reduced renal function.

Research progress on related mechanisms of uric acid activating NLRP3 inflammasome in chronic kidney disease

Hyperuricemia is an independent risk factor for the progression of chronic kidney disease. High levels of uric acid can lead to a series of pathological conditions, such as gout, urinary stones, inflammation, and uric acid nephropathy. There is a close relationship between uric acid and the NLRP3 inflammasome. NLRP3 inflammasome activation can cause cell damage and even death through endoplasmic reticulum stress, lysosome destruction, mitochondrial dysfunction, and the interaction between the Golgi apparatus and extracellular vesicles. In addition, the NLRP3 inflammasome acts as a molecular platform, triggering the activation of caspase-1 and the lysis of IL-1β, IL-18 and Gasdermin D (GSDMD) through different molecular mechanisms. Cleaved NT-GSDMD forms pores in the cell membrane and triggers pyrophosphorylation, thereby inducing cell death and releasing many intracellular proinflammatory molecules. In recent years, studies have found that hyperuricemia or uric acid crystals can activate NLRP3 inflammasomes, and the activation of NLRP3 inflammasomes plays an important role in kidney disease. This article reviews the possible pathophysiological mechanisms by which uric acid activates inflammasomes and induces kidney damage at the cellular and molecular levels.

Effect of Urate-Lowering Therapy on the Progression of Kidney Function in Patients With Asymptomatic Hyperuricemia: A Systematic Review and Meta-Analysis

Background: Hyperuricemia is involved in the risk of chronic kidney disease (CKD). However, whether urate-lowering therapy (ULT) can influence the progression of kidney function in patients with asymptomatic hyperuricemia is still controversial. We conducted a systematic review and meta-analysis to evaluate the effect of ULT on the progression of kidney function in asymptomatic hyperuricemia patients.

Methods: The MEDLINE, EMBASE and Cochrane databases were searched without language, national or ethnic restrictions for randomized controlled trials published prior to November 30, 2020, that compared ULT with controlled therapy in patients with asymptomatic hyperuricemia.

Results: Eleven studies were included for qualitative synthesis. ULT did not ameliorate eGFR slopes (WMD 0.36 ml/min/1.73 m² per year, 95% CI: −0.31, 1.04), or lead to reductions in kidney events (RR 1.26; 95% CI: 0.80, 2.00) or all-cause mortality (RR 1.00; 95% CI: 0.65, 1.55), although ULT resulted in a decrease in serum uric acid levels (WMD −2.73 mg/dl; 95% CI: −3.18, −2.28) and lowered the incidence of gout episodes (0.9 vs 2.7%, RR 0.38; 95% CI: 0.17, 0.86).

Conclusion: In patients with asymptomatic hyperuricemia, ULT did not decay the progression of kidney function. Long-term and larger sample studies are needed to verify the results.

Systematic Review Registration: [www.crd.york.ac.uk/PROSPERO/#recordDetails], identifier [CRD42020204482].

Effects of Dietary Tributyrin on Growth Performance, Biochemical Indices, and Intestinal Microbiota of Yellow-Feathered Broilers

This study aimed to evaluate the effects of tributyrin on growth performance, biochemical indices and intestinal microbiota of yellow-feathered broilers. 360 one-day-old chicks were randomly allocated to three treatments with six replicates of 20 chicks each, including a normal control group (NC), an antibiotic group (PC), and a tributyrin (250 mg/kg) group (TB) for 63 days. The results showed that compared with the control, the feed conversion ratio (FCR) in the TB group decreased during the d22 to d42 (p < 0.05) and overall, the final weight and FCR of broilers tended to increase and decrease, respectively. Moreover, the TB group showed the highest creatine concentrations at the entire period (p < 0.05). TB treatment increased the Bacteroidetes relative abundance and decreased Firmicutes. Principal coordinates analysis yielded clear clustering of the three groups. Linear discriminant analysis effect size analysis found seven differentially abundant taxa in the TB group, including several members of Bacteroidedetes. The relative abundance of Eisenbergiella, Phascolarctobacterium, Megasphaera and Intestinimonas increased in tributyrin-treated broilers. Spearman correlation analysis identified a correlation between Eisenbergiella abundance and overall feed efficiency. These results demonstrated that tributyrin could improve the growth performance by modulating blood biochemical indices and the cecal microflora composition of broilers.

Cumulative Serum Uric Acid and Its Time Course Are Associated With Risk of Myocardial Infarction and All-Cause Mortality

Background Serum uric acid (SUA) has been demonstrated as a risk factor for myocardial infarction (MI) and all-cause mortality; however, the impact of cumulative SUA (cumSUA) remains unclear. We aimed to investigate the association of cumSUA with MI risk and all-cause mortality, and to further explore the effects of SUA accumulation time course. Methods and Results The study enrolled 53 463 participants without a history of MI, and these participants underwent 3 examinations during 2006 to 2010. cumSUA from baseline to the third examination was calculated, multiplying mean values between consecutive examinations by time intervals between visits. Cox models estimated hazard ratios (HRs) and 95% CIs of MI and all-cause mortality for cumSUA quartiles, hyperuricemia exposure duration, and SUA accumulation time course. During a median follow-up of 7.04 years, 476 incident MIs and 2692 deaths occurred. In the fully adjusted model, a higher MI risk was observed in the highest cumSUA quartile (HR, 1.48; 95% CI, 1.10-1.99), in participants with longer hyperuricemia exposure duration (HR, 1.71; 95% CI, 1.06-2.73), and in participants with cumSUA≥median and a negative slope (HR, 1.58; 95% CI, 1.18-2.11). Similar associations persisted for all-cause mortality. Conclusions The risk of MI and all-cause mortality increased with higher cumSUA and was affected by the SUA accumulation time course. Early SUA accumulation contributed more to MI risk and all-cause mortality than later SUA accumulation with the same overall cumulative exposure, emphasizing the importance of optimal SUA control early in life.

Hyperuricemia and chronic kidney disease: to treat or not to treat

Hyperuricemia is common in chronic kidney disease (CKD) and may be present in 50% of patients presenting for dialysis. Hyperuricemia can be secondary to impaired glomerular filtration rate (GFR) that occurs in CKD. However, hyperuricemia can also precede the development of kidney disease and predict incident CKD. Experimental studies of hyperuricemic models have found that both soluble and crystalline uric acid can cause significant kidney damage, characterized by ischemia, tubulointerstitial fibrosis, and inflammation. However, most Mendelian randomization studies failed to demonstrate a causal relationship between uric acid and CKD, and clinical trials have had variable results. Here we suggest potential explanations for the negative clinical and genetic findings, including the role of crystalline uric acid, intracellular uric acid, and xanthine oxidase activity in uric acid-mediated kidney injury. We propose future clinical trials as well as an algorithm for treatment of hyperuricemia in patients with CKD.

Research Advances in the Mechanisms of Hyperuricemia-Induced Renal Injury

Uric acid is the end product of purine metabolism in humans, and its excessive accumulation leads to hyperuricemia and urate crystal deposition in tissues including joints and kidneys. Hyperuricemia is considered an independent risk factor for cardiovascular and renal diseases. Although the symptoms of hyperuricemia-induced renal injury have long been known, the pathophysiological molecular mechanisms are not completely understood. In this review, we focus on the research advances in the mechanisms of hyperuricemia-caused renal injury, primarily on oxidative stress, endothelial dysfunction, renal fibrosis, and inflammation. Furthermore, we discuss the progress in hyperuricemia management.

Impact of serum uric acid on renal function after bariatric surgery: a retrospective study

BACKGROUND

Despite a known negative association between serum uric acid level (SUA) and renal function, this correlation in patients after bariatric surgery remains unknown.

OBJECTIVE

To assess correlation between postoperative SUA and estimated glomerular filtration rate (eGFR) at 12 months after bariatric surgery.

SETTING

A single tertiary referral center.

METHODS

A total of 252 patients (age = 40.5 ± 11.2; body mass index = 39.0 ± 5.5 kg/m²) undergoing bariatric surgery divided into 2 groups (i.e., normal renal function [90 ≤ eGFR < 125 mL/min/1.73 m², n = 176] versus renal function impairment [eGFR < 90 mL/min/1.73 m², n = 76]) were assessed for relationships between SUA and eGFR in both groups (primary endpoint) and associations of percentage weight loss with changes in SUA (△SUA) and eGFR (△eGFR) for all patients (secondary endpoint) at 12 months.

RESULTS

Overall, prevalence of hyperuricemia was 40.4% and 22.2% (baseline and postoperative 12 mo, respectively). Reverse relationship was observed between SUA and eGFR (r = -.152, P = .007) for all patients with no association noted between baseline SUA and eGFR in each group as well as between SUA and eGFR at 12 months in the normal group (r = -.076, P = .437). The reverse relationship was found (r = -.417, P = .005) in renal function impairment group for whom SUA was identified as a predictor of eGFR at 12 months. There was no association of percentage weight loss with △SUA (r = .089, P = .601) and △eGFR (r = -.046, P = .785).

CONCLUSION

The results demonstrated a negative relationship between postoperative SUA and renal function in patients with preexisting renal dysfunction undergoing bariatric surgery. Clinical significance of our findings warrants further investigation.

Retrospective Analysis of the Correlation between Uric Acid and Thyroid Hormone in People with Normal Thyroid Function

OBJECTIVE

This study adopts the method of retrospective analysis to collect general information and laboratory results of physical examination population, hoping to clarify the correlation between uric acid and thyroid hormone.

METHODS

The subjects of the study were healthy subjects who underwent physical examination at the Sir Run Run Shaw Hospital affiliated to the Medical College of Zhejiang University from January 2016 to December 2018. Demographic information and medical history of all subjects were recorded through an electronic health system. Serum uric acid (SUA) was grouped by quartiles. Statistical analyses were performed with R version 3.5.1.

RESULTS

A total of 48,526 subjects were included in the analysis. Gender ratio, age, BMI, waist circumference, systolic blood pressure, diastolic blood pressure, FBG, HbA1c, TG, HDL-C, ALT, AST, FT3, FT4, and TSH were significantly different among the uric acid groups. The regression coefficients of SUA in the TSH, FT3, and FT4 regression models were B = 1.000 (95% CI 1.000-1.000, p = 0.009), B = 0.999 (95% CI 0.999-0.999, p < 0.001), and B = 1.001 (95% CI 1.001-1.001,  p < 0.001), respectively. There was a significant dose-dependent relationship between FT4, FT3, and SUA gradient.

CONCLUSIONS

Under normal thyroid function, there were significant differences in TSH, FT3, and FT4 between groups with different uric acid levels. Uric acid levels were linearly correlated with FT3 and FT4, but not with TSH.