Exploring the Brain - Gut Microbiota - Kidney Interactive Damage Mechanisms Underlying Cognitive Decline in Patients With IgA Nephropathy Using Ultra-high Field Magnetic Resonance Imaging

Inclusion criteria

• Right-handed individuals, age 18-60 years;
• Diagnosis of IgA nephropathy confirmed by renal biopsy.

Exclusion criteria

• Secondary IgA nephropathy, such as that associated with systemic lupus erythematosus, rheumatoid arthritis, Sjögren's syndrome, hepatitis B or C infection, or drug-induced causes.
• History of kidney transplantation, hemodialysis, or peritoneal dialysis.
• Acute cerebrovascular event within the past 3 months; a history of severe traumatic brain injury, brain tumor, stroke, or encephalomalacia that has resulted in identifiable lesions or significant asymmetry of cranial anatomy.
• Malignant tumors; a history of intestinal surgery; or irritable bowel syndrome (IBS).
• Use of antibiotics, steroids, immunosuppressants, or microbiota-based preparations within the past month.
• Inflammatory bowel disease (IBD); or the presence of symptoms such as diarrhea, abdominal pain, or IBS-like symptoms within the past two weeks.
• History of alcohol dependence.
• Current use of psychiatric medications, such as antidepressants or anxiolytics.
• Loss of hearing or vision.
• Pregnancy or lactation.
• Current participation in another clinical trial.

Contraindications for 7.0T MRI Presence of ferromagnetic implants in the body (e.g., cardiac pacemakers, defibrillators, neurostimulators, aneurysm clips, cochlear implants, or any other metallic foreign bodies).

Non-ferromagnetic implants (e.g., titanium alloy, orthopedic implants), intrauterine devices (IUDs), or non-removable dental prosthetics (including dental implants).

Metallic foreign bodies in the eye or body (e.g., metal fragments, shrapnel, or metallic debris), such as in individuals with a history of welding or metal-related injuries.

Tattoos or permanent makeup (e.g., on eyebrows or lips) acquired within the last month.

Claustrophobia. Fever. Inclusion Criteria for the Healthy Control Group

All healthy controls must meet the following criteria:

• Right-handed, aged 18-60 years;
• All physiological indicators within the normal range, with no signs of disease;
• No family history of psychiatric or neurological disorders.

Exclusion criteria

for the Healthy Control Group

• History of cranial surgery, brain tumor, traumatic brain injury, stroke, or encephalomalacia resulting in significant asymmetry of cranial anatomy;
• History of psychiatric disorders, alcohol dependence, or central nervous system diseases;
• Presence of metallic foreign bodies in the body or claustrophobia, making them unsuitable for MRI scanning;
• History of hypertension, diabetes, or hyperlipidemia;
• Hearing or vision impairment that would affect communication during the MRI scan or the completion of cognitive assessments.