Study Procedures：
1. Total Number of Subjects The total number of subjects planned for enrollment is 100.
The study will include two groups:
1. Experimental Group: 50 patients receiving AST-120 (6g/day) in combination with standard post-AKD care.
2. Control Group: 50 patients receiving only standard post-AKD care. The sample size is determined based on the statistical power needed to detect a significant difference in the primary endpoint (percentage changes in IS levels), with consideration for potential dropout rates. The evaluable number is estimated to be close to 90, allowing for a 10% dropout rate, making the enrolled number 100.
2\. Interventions, Procedures, and Tests for Each Group
Subjects will undergo the following interventions, procedures, and tests according to the schedule:
1. Baseline (Day 0):
\- Demographic data collection.
* Blood tests for serum creatinine, eGFR, IS, p-CS, and urinary albumin-to-creatinine ratio (UACR).
* Randomization into experimental or control groups.
2. Treatment Period (Day 1-14):
* Experimental Group: Receive AST-120 (6g/day, divided into three doses per day).
* Control Group: Standard post-AKD care only.
* Both groups will undergo regular clinical assessments and adverse event monitoring.
3. Day 14:
* Blood tests for IS, p-CS, serum creatinine, eGFR, and UACR.
* Follow-up (Day 90 and Day 180):
* Assess eGFR, serum creatinine, UACR.
* Monitor for major adverse kidney events (MAKE) and major adverse cardiovascular events (MACE).
3\. Trial Procedure Timeline
The trial procedure follows this timeline:
1. Day 0: Baseline measurements and randomization.
2. Day 1-14: Treatment phase (AST-120 administration or standard care).
3. Day 14: Blood tests and assessment of treatment efficacy.
4. Day 90 and Day 180: Follow-up visits for MAKE and MACE assessments, and blood tests for kidney function.
4\. Specimen Collection and Processing
1. Specimen: Blood samples will be collected on Day 0 (baseline), Day 14 (end of treatment), Day 90, and Day 180 (follow-up).
2. Transport and Storage: Specimens will be transported to the laboratory within the hospital for immediate processing. They will be stored in a temperature-controlled facility if needed.
3. Processing: Blood samples will undergo centrifugation for serum separation. Serum will be used for measuring IS, p-CS, serum creatinine, and other biomarkers.
4. Analysis: The following tests will be performed:
* IS and p-CS levels.
* Serum creatinine and eGFR.
* UACR.
5\. Clinical Data Collection and Questionnaires
Clinical data collected will include:
1. Demographic data (age, sex, medical history).
2. Lab results for IS, p-CS, creatinine, eGFR, UACR. No specific questionnaires will be used for this study.
