Table 2.

Characteristics of the studies included in this meta-analysis.

First Author/Year	country	Follow-up time	Age, mean ± SD/ Age range (years)	Women n (%)	Study design	Sample size	Experiment group		Control group	Assessment point of UPDRS	Minors
							Stem cell type	Transplantation route
Xiaoqun et al. (2013) (13)	China	60 days	62.0 ± 4.2	5 (45.5%)	clinical trial	22	Fetal tissue-derived neural stem cell	Intrathecal injection	Levodopa	Baseline, 1, 3, 7, 30 and 60 days	14
Lige and Zengmin (2014) (14)	China	2 years	57.3 ± 9.1	6 (28.6%)	clinical trial	21	Fetal tissue-derived neural stem cell	Intraventricular injection	Levodopa	Baseline, 2 years	15
Schiess et al. (2021) (15)	USA	52 weeks	66.4 ± 5.9	3 (60%)	phase I study	5	Bone marrow mesenchymal stem cell	Intravascular injection	Dopaminergic regimen	Baseline, 3, 12, 24, and 52 weeks	17
Sun et al. (2016) (17)	China	3 weeks	65.3 ± 2.7	4 (40%)	clinical trial	10	Umbilical cord mesenchymal stem cell	Intravascular injection	Levodopa	Baseline, 1 month	16
Yan et al. (2014) (18)	China	1 month	63.4 ± 7.6	7 (46.7%)	clinical trial	15	Umbilical cord mesenchymal stem cell	Intravascular injection	Drug treatment	Baseline, 1 month	14
Yun et al. (2011) (19)	China	1 month	58.4 ± 8.7	4 (50%)	clinical trial	8	Umbilical cord mesenchymal stem cell	Intravascular injection	Levodopa	Baseline, 1 month	14
Aili (2013) (20)	China	6 months	67.1 ± 5.3	4 (44.4%)	Clinical trial	9	Umbilical cord mesenchymal stem cell	Intrathecal injection	Levodopa	Baseline, 28 days, 6 months	16
Yin et al. (2012) (21)	China	36 months	66.0 ± 11.4	4 (44.4%)	pilot clinical trial	9	Human retinal pigment epithelium cell	Intraventricular injection	Levodopa	Baseline, 3, 6, 12, 24 and 36 months	13
Dapeng et al. (2013) (26)	China	12 weeks	45–66	14 (46.7%)	clinical trial	30	Umbilical cord mesenchymal stem cell	Intrathecal injection	Compound levodopa	Baseline, 4 and 12 weeks	15