The conventional treatment plan was supplemented with intravenous injection of normal saline (in a blinded manner)

In addition to the conventional treatment regimen, intravenous infusion of umbilical cord blood mononuclear cells (1×10^8 cells per infusion) will be administered. The infusions will be carried out via the intravenous route at one - week intervals for a total of four consecutive times. One month after the completion of the fourth infusion, the fifth infusion will be performed.

In addition to the conventional treatment regimen, intravenous infusion of umbilical cord blood mononuclear cells (3×10^8 cells per infusion) will be administered. The infusions will be carried out via the intravenous route at one - week intervals for a total of four consecutive times. One month after the completion of the fourth infusion, the fifth infusion will be performed.

When performing cell infusion, it is essential to use an infusion set and follow the standard blood transfusion procedures. Before, during, and after the infusion, monitor the patient's body temperature, pulse, breathing, and blood pressure. When infusing cells, first flush the tube with 20-30 ml of 0.9% sodium chloride, and start the infusion at a rate of 20-30 drops per minute. After half an hour, if there are no adverse reactions, increase the rate to 30-50 drops per minute. During the cell infusion process, gently shake the cell bag once every 15 minutes. After the infusion is completed, flush the cell preservation bag with 20 ml of 0.9% sodium chloride and gently shake it. After that, use 0.9% sodium chloride to rinse the infusion set to remove the cells completely, to ensure the quantity of cell infusion.

The Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB) assesses cognitive functions through six different sub-items, including memory, orientation, judgment and problem-solving ability, social skills, family life and hobbies, and self-care ability.

The total score of CDR-SB ranges from 0 to 18. The higher the score, the worse the patient's cognitive function and daily living ability.

This helps to provide a more comprehensive understanding of the patient's cognitive functions in all aspects.

The assessors need to undergo professional training, be familiar with the assessment methods and scoring criteria, and avoid being influenced by subjective factors in the assessment results.

During the assessment process, it is necessary to have adequate communication with the respondents and caregivers to understand the medical history and living conditions, in order to obtain more accurate information.

Activity of Daily Living Scale（ADL） is commonly used to assess the daily living abilities of the elderly, and it plays a crucial role in the screening of Alzheimer's disease (AD) and mild cognitive impairment (MCI).

The minimum score is 16 (which is completely normal). Scores above 16 indicate varying degrees of functional decline, with the maximum being 56.

The ADL scale consists of 14 items and is divided into two parts: the first part is the self-care scale for physical activities, including activities such as using the toilet, eating, dressing, daily hygiene, walking, and bathing. The second part is the instrumental daily living ability scale, including activities such as making phone calls, shopping, cooking, housework, taking public transportation, taking medicine, and managing finances.

The level of P-tau 181 shows a strong correlation with the density of Tau tangles in the brain. The levels of P-tau 181 in the cerebrospinal fluid and blood of patients with Alzheimer's disease were significantly higher than those of patients with other neurodegenerative diseases and the normal population. The increase in P-tau 217 is closely related to another core pathological feature of the brain - the deposition of β-amyloid plaques.

At the corresponding time point, blood samples (1.5 - 3 mL) were taken from the patients, and the levels of P-tau 181 and P-tau 217 were quantified using chemiluminescent enzyme immunoassay (cLEIA).