Clinical Useful Information | Non-invasive renal biopsy - Liquid biopsy enters the clinic and will be popular!

Liquid biopsy is a non-invasive technology that analyzes specific components in body fluids such as blood, urine, ascites, saliva, etc. It can not only obtain relevant disease information, but also overcome some disadvantages of traditional biopsy.

In the diagnosis and treatment of kidney diseases, renal biopsy is a very common examination method. It is an invasive examination that obtains a small amount of renal biopsy tissue from the patient's kidney through puncture or surgery for pathological examination. It has the limitations of high cost and cumbersome operation. Therefore, it is necessary to explore and develop new non-invasive or low-invasive diagnostic technologies such as liquid biopsy to replace or supplement traditional renal biopsy.

Liquid biopsy has obvious advantages in the diagnosis and monitoring of kidney disease.

1. Non-invasive: No painful tissue collection is required.

2. Frequent and multiple testing is possible: dynamic monitoring of disease progression can be achieved.

3. Wide range of indications: It can be used for the diagnosis and monitoring of various diseases.

4. Guide treatment: can be used to develop individualized treatment plans.

5. Quickly determine the efficacy and monitor the occurrence of drug resistance.

What tests are included in kidney liquid biopsy? Currently, the main source of kidney liquid biopsy specimens is urine, and the test items include exfoliated cells, proteins and peptides, nucleic acids and exosomes in urine.

1. Urinary exfoliated cells: Podocytes in urine are an important indicator for understanding the state of kidney disease, because podocyte abnormalities are associated with a variety of diseases, such as diabetic nephropathy, IgA nephropathy, etc. Some studies have shown that podocytes in urine can be used as a marker for early diagnosis of kidney disease. However, from a methodological point of view, there is currently no fully clinically recognized method for detecting podocytes in urine, and more detection technologies need to be developed and applied in the future.

2. Proteins and peptides: About 70% of the proteins and peptides in urine come from the kidneys, so urine proteomics can reflect most of the information about the kidneys. Some proteins and peptides have been used in the study of diseases such as idiopathic membranous nephropathy, providing potential markers for early diagnosis. For example, anti-phospholipase A2 receptor antibodies. Among patients with membranous nephropathy, 70% to 80% of patients have positive anti-phospholipase A2 receptor antibodies. Among patients with positive anti-phospholipase A2 receptor antibodies, 99% to 100% of patients have membranous nephropathy. In other words, when the antibody is found to be positive, nearly 100% of them have membranous nephropathy.

3. Nucleic acid: Nucleic acid testing includes cfDNA, miRNA, lncRNA, circRNA, etc. cfDNA increases significantly in the blood during infection, inflammation, tumors and other diseases, and has been used in the diagnosis of kidney disease. Non-coding RNAs such as miRNA, lncRNA, circRNA also play an important role in kidney disease research.

4. Exosomes: It is an extracellular vesicle containing components such as DNA, RNA and protein. Recent studies have found that the content of exosomes in urine is related to the degree of kidney damage and may be used as a monitoring marker for kidney disease. However, there is currently no consensus on the methods and technologies for the isolation and identification of exosomes, and more research is needed to establish unified standards in the clinical application process.

What is the clinical use of renal liquid biopsy?

1. Early screening and clinical diagnosis: Early detection and diagnosis are crucial for kidney diseases, especially those that are difficult to reverse. Liquid biopsy provides a new approach for early diagnosis by looking for highly sensitive and specific biomarkers, such as TIMP2 and IGFBP7. These markers can play a role in cell cycle arrest that occurs in the early stages of the disease, thereby predicting the risk of kidney damage in advance.

2. Treatment monitoring and prognosis assessment: Liquid biopsy has potential value in dynamic monitoring during treatment. By tracking changes in biomarkers, it helps clinicians better understand the status of the disease and adjust treatment plans in a timely manner. For example, studies on IgA nephropathy have shown that high levels of autoantibodies IgG are associated with poor prognosis, which can be used to assess patients' risk of disease progression; for membranous nephropathy, monitoring serum PLA2R antibody levels can track treatment effects and adjust treatment plans in a timely manner.

3. Monitoring renal transplant rejection: Renal transplantation is a treatment for end-stage renal disease, and liquid biopsy also has potential applications in the detection of renal transplant rejection. Traditional histological analysis has certain limitations, while donor-derived cfDNA testing can more frequently, quantitatively, and safely assess rejection and injury status. Studies have shown that cfDNA levels are associated with rejection status, which is crucial for early detection of rejection and intervention measures.

What challenges still exist in renal liquid biopsy technology?

1. Improved sensitivity and specificity: Liquid biopsy requires higher sensitivity and specificity for early screening and diagnosis.

2. Technology automation and standardization: To achieve clinical application, liquid biopsy technology needs more automation and standardization. This will help improve the speed and quality of detection and reduce human errors.

3. Data processing and analysis: The data generated by liquid biopsy is huge, requiring efficient data processing and analysis methods. Artificial intelligence may play a key role in this field.

4. Clinical validation: Although liquid biopsy has shown potential in research, its feasibility and accuracy in clinical practice require more large-scale clinical validation.

5. Explore more new indicators: The discovery and validation of disease-related markers is an ongoing challenge that requires extensive research and validation.

summary

The application of liquid biopsy technology in the field of kidney disease has brought revolutionary changes to the medical community. From early screening to treatment monitoring, liquid biopsy provides more tools and methods for kidney disease. Although there are still challenges, the research and technological development in this field has a bright future and is expected to improve the early diagnosis and treatment of kidney disease and bring more hope to patients' health.