Phenylacetylglutamine (PAG), a gut microbiota metabolite, is associated with cardiovascular diseases. Arterial stiffness (AS), which is a marker of aging-associated vascular diseases, is an independent risk factor for cardiovascular morbidity and mortality. This study aimed to assess the correlation between serum PAG levels and AS in kidney transplantation (KT) patients, potentially uncovering new insights into the cardiovascular risks in this population. In this study, 100 KT patients were included. Carotid–femoral pulse wave velocity (cfPWV) was measured, and patients with cfPWV > 10 m/s were categorized as the AS group. Serum PAG levels were assessed using liquid chromatography–tandem mass spectrometry. Thirty KT patients (30.0%) exhibited AS, with higher percentages of diabetes mellitus, older age, and elevated levels of systolic blood pressure, serum fasting glucose, and PAG than the control group. After adjusting for factors significantly associated with AS by multivariate logistic regression analysis, serum PAG, age, fasting glucose levels, and systolic blood pressure were independent factors associated with AS. Furthermore, PAG levels had a negative correlation with the estimated glomerular filtration rate and a positive correlation with cfPWV values. Serum PAG levels are positively associated with cfPWV values and are a biomarker of AS in KT patients.

BACKGROUND Trimethylamine N-oxide (TMAO), a gut-derived uremic toxin, is linked to hypertension, cardiovascular events, and mortality. Peripheral arterial disease (PAD), defined by a low ankle-brachial index (ABI), increases mortality in kidney transplantation (KT) recipients. This study investigated the association between serum TMAO levels and PAD in KT recipients. MATERIAL AND METHODS This cross-sectional study included 98 KT recipients. Serum TMAO levels were quantified using liquid chromatography-mass spectrometry, and ABI values were assessed with an automated oscillometric device. Patients with ABI <0.9 were categorized as having PAD. Additional clinical and laboratory data were collected from medical records for analysis. RESULTS Among 98 KT recipients, 22 (22.4%) had low ABI values. The low-ABI group had higher serum TMAO levels (P<0.001) and a higher diabetes prevalence (P=0.035). In multivariate analysis, serum TMAO levels were independently associated with PAD (odds ratio: 1.154, 95% CI: 1.062-1.255, P=0.001). Both the left and right ABI values were negatively correlated with TMAO levels (P<0.001). In the Spearman correlation analysis, the estimated glomerular filtration rate (eGFR) was negatively correlated with TMAO levels (P=0.005). The area under the receiver operating characteristic curve for TMAO predicting PAD was 0.868 (95% CI: 0.784-0.928, P<0.001). CONCLUSIONS Elevated serum TMAO levels are independently associated with PAD in KT recipients, as evidenced by their significant negative correlation with ABI values. These findings suggest that TMAO may serve as a potential biomarker for identifying KT recipients at higher risk of PAD.

Although kidney transplantation (KT) restores renal function, residual uremic toxins, such as indoxyl sulfate (IS), may persist and contribute to vascular remodeling and aging. Aortic stiffness, reflected by carotid–femoral pulse wave velocity (cfPWV), is a strong predictor of cardiovascular events. This study enrolled KT recipients to examine the association of circulating IS with aortic stiffness. Using the SphygmoCor system, we assessed aortic stiffness, which was defined as cfPWV > 10 m/s. Serum IS concentrations were measured by liquid chromatography–tandem mass spectrometry. Of 94 KT recipients, 26 (27.7%) met the criteria for aortic stiffness. Compared with patients without aortic stiffness, those with aortic stiffness were older (p = 0.017) and had significantly higher systolic blood pressure (p = 0.011) and fasting glucose levels (p = 0.002), a higher prevalence of diabetes (p = 0.043), and higher IS levels (p = 0.002). According to multivariable logistic regression, serum IS remained independently associated with aortic stiffness (p = 0.017). According to stepwise linear regression, log-transformed IS further showed a positive correlation with cfPWV (p = 0.016). Serum IS remained an independent determinant of aortic stiffness in KT recipients, highlighting the burden of residual uremic toxins as a contributor to post-transplant vascular aging.

Background: p-Cresyl sulfate (PCS) has been linked to vascular dysfunction through endothelial injury and vascular remodeling. Peripheral artery disease (PAD), identified by a low ankle–brachial index (ABI), is associated with increased mortality in kidney transplant (KT) recipients. This study investigated the association between serum PCS levels and PAD (as defined by ABI) in KT recipients. Methods: This cross-sectional, single-center study included 90 KT recipients. Serum total PCS levels were quantified using liquid chromatography–mass spectrometry. ABI was measured using an automated oscillometric device, and PAD was defined as ABI < 0.9. Results: Among the 90 KT recipients, 20 (22.2%) met the ABI for PAD. Patients with ABI-defined PAD had a significantly higher prevalence of diabetes mellitus (p = 0.036) and serum PCS levels (p = 0.001). Multivariate logistic regression analysis adjusting for potential confounders revealed that serum PCS levels remained independently associated with PAD (odds ratio 1.254, 95% confidence interval 1.108–1.419; p < 0.001). PCS levels were inversely correlated with both left (r = −0.339, p = 0.001) and right (r = −0.357, p < 0.001) ABIs. The association remained consistent in penalized regression models. Conclusions: Higher serum PCS levels were independently associated with ABI-defined PAD in KT recipients. The findings indicate that residual uremic toxin burden may contribute to peripheral vascular disease despite the restoration of renal function following transplantation.

Background Pediatric urolithiasis is increasingly recognized not merely as a localized urinary disorder but as part of a systemic metabolic–inflammatory process that may predispose to chronic kidney and cardiovascular disease. However, population-based data in Asian pediatric populations with urolithiasis remain limited. This nationwide study investigated the epidemiologic trends, metabolic risk factors, and systemic outcomes associated with pediatric urolithiasis in Taiwan. Methods Using the National Health Insurance Research Database, children newly diagnosed with urolithiasis between January 2009 and December 2018 were identified and matched with controls according to age, sex, and index year. Comorbidities and medication exposures were evaluated, and outcomes including renal, cardiovascular, and metabolic complications were analyzed using Cox proportional hazards models. Results Among 10,113 affected children and 101,130 matched controls, the annual incidence of pediatric urolithiasis declined from 23.9 to 16.2 per 100,000 persons. A male predominance and peak incidence during adolescence were noted. Major associated factors included hypercalciuria (adjusted hazard ratio [aHR] 31.5), congenital urinary anomalies (aHR 22.6), urinary tract infection (aHR 8.3), and exposure to diuretics or antibiotics. Compared with controls, children with urolithiasis had significantly higher risks of chronic kidney disease (aHR 5.9), hypertension (aHR 1.9), ischemic heart disease (aHR 1.9), and dyslipidemia (aHR 1.8). Conclusions Despite a modest decline in incidence, pediatric urolithiasis remains a clinically important condition associated with long-term renal and cardiovascular morbidity. These findings highlight the importance of early metabolic evaluation, careful medication stewardship, and continued nephrology follow-up to mitigate chronic sequelae.

Hsiao-Hui Yang, Ching-Chun Ho, Chia-Ling Lee, Yi-Feng Wu, Yen-Cheng Chen. Clin Transplant Res 2024;38:145-9. https://doi.org/10.4285/ctr.24.0002