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.

Fluorine-18 fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) is widely used to evaluate patients with cancer and to detect various inflammatory processes. Here, we report a rare case of a 53-year-old woman with breast cancer who developed generalized pain, weakness, rash, and edema over the trunk after the first cycle of neoadjuvant pembrolizumab and cytotoxic chemotherapeutic agents. ¹⁸F-FDG PET revealed diffusely increased uptake in the muscles without skeletal or visceral metastasis, aiding in the diagnosis of paraneoplastic and pembrolizumab-associated myositis and subsequent monitoring. This case underscores the value of ¹⁸F-FDG PET in differentiating myositis from tumor progression and monitoring treatment response in such cases.