The goal of this clinical trial is to evaluate the safety, tolerability and preliminary efficacy that iDAP has on Parkinson's disease (PD) patients.

Parkinson's disease (PD) is a common neurodegenerative disease in the middle-aged and elderly. It is the "third killer" of the middle-aged and elderly after tumors and cardiovascular and cerebrovascular diseases. Its main clinical manifestations are resting tremor, reduced voluntary movement, muscle rigidity, postural reflex impairment, and autonomic dysfunction, which seriously affect patients' work ability and quality of life. It is estimated that nearly 100,000 people in China become new Parkinson's patients every year. Experts from the World Health Organization predict that the number of Parkinson's patients in China will reach 5 million in 2030, which will be more than half of the world's total. As the disease progresses, the symptoms of Parkinson's patients will become increasingly severe. The high prevalence and high disability rate of Parkinson's disease bring heavy burdens to individuals, families, and society.

Inclusion Criteria:

• Ages between 45 and 75 years;
• Diagnosed to be Parkinson's disease patients according to MDS Parkinson's disease diagnostic criteria;
• Disease history 4-20 years;
• Hoehn and Yahr Stage 2-4;
• Stable dose of dopamine for more than 3 months;
• Improvement of MDS-UPDRS part III;

Exclusion Criteria:

• Patients who have previously undergone brain surgery;
• Past use of stem cell therapy or participation in stem cell clinical research;
• Cognitive impairment;
• History of mental disorders;
• Patients with other serious systemic diseases;
• Past or current metastatic malignant tumors.