Baseline characteristics of participants
95 patients were recruited in this study at baseline (Tai Chi group 32, brisk walking group 31, control group 32). All of them were Han ethnicity. No patients presented either on-off phenomenon or dyskinesias. Three groups were matched in age, gender, disease duration and education. 66 patients finished 6-month and 12-month follow-up. Details were shown in Table 1 and Figure 1. There were no differences of levodopa equivalent daily dosage (LEDD) at baseline and 12-month visit between the groups.
Table 1 Demographic information of all the subjects
|
Tai Chi Group
(N = 32)
|
Brisk Walking Group
(N = 31)
|
Control Group
(N = 32)
|
p value
|
Gender, Female (N (%))
|
15 (46·88)
|
9 (29·41)
|
13 (41·18)
|
0·500
|
Age at baseline (mean ± SD)
|
62·7 (5·51)
|
61·9 (5.64)
|
61·9 (6·76)
|
0·400
|
Education, years (mean ± SD)
|
13·60 (2·71)
|
13·10 (2·57)
|
12·40 (2·83)
|
0·472
|
History of Hypertension (N (%))
|
7 (21·88)
|
3 (11·76)
|
5 (17·65)
|
0·800
|
History of Diabetes mellitus (N (%))
|
1 (3·13)
|
0 (0·00)
|
1 (3·13)
|
1·000
|
History of smoking (N (%))
|
2 (6·25)
|
2 (6·25)
|
2 (6·25)
|
0·600
|
Family History (N(%))
|
8 (25·00)
|
5 (17·65)
|
3 (11·76)
|
0·600
|
Tremor dominant (N (%))
|
22 (68·75)
|
22 (64·71)
|
17 (58·82)
|
0·800
|
Disease duration (mean ± SD)
|
5·91 (4·01)
|
3·82 (1·87)
|
4·32 (2·46)
|
0·082
|
Hoehn – Yahr staging (N (%))
1·0
1·5
2·0
2·5
|
9 (28·13)
5 (15·63)
13 (40·63)
5 (15·63)
|
8 (25·81)
7 (22·58)
13 (41·94)
3 (9·68)
|
1 (3·13)
11 (34·38)
13 (40·63)
7 (21·88)
|
0·097
|
LEDD at baseline (mean ± SD)
|
326 (197)
|
260 (174)
|
347 (109)
|
0·800
|
LEDD (mean ± SD)
|
56·33 (91·68)
|
39.71 (83·30)
|
57·21 (107·24)
|
0·939
|
LEDD, levodopa equivalent daily dosage; N, number; SD, standard deviation
LEDD: LEDD at 12 months minus LEDD at baseline
|
Clinical improvements
Patients showed better performance after Tai Chi training in BBS (p≤0.035). In addition, Tai Chi improved the performance in BBS (6 months: p= 0.006, 12 months: p=0.044) since 6 months and lasted to 12 months. Compared to brisk walking, Tai Chi had more advantages in improving BBS scores (6 months: p= 0.005, 12 months: p=0.022). (Additional File 2-Table S1, Figure 2.A)
Patients showed better changes after Tai Chi training in UPDRS and TUG (p≤0.045). Tai Chi group showed improvement in UPDRS at 12 months compared with controls (UPDRS: p= 0.015, UPDRS-III: p <0.001). In addition, Tai Chi improved the performance in TUG (6 months: p= 0.017, 12 months: p=0.011). Tai Chi improved patients’ performance in step width (severer side: 6 months: p= 0.002, 12 months: p <0.001; milder side: 6 months: p <0.001, 12 months: p <0.001) compared with controls since 6 months and lasted to 12 months. When compared to brisk walking, Tai Chi also showed advantages in improving step width (severer side: 6 months: p= 0.03, 12 months: p=0.03; milder side: 6 months: p=0.004, 12 months: p=0.111). (Additional File 2-Table S1, Figure 2. B-D)
Mechanisms of Tai Chi effects
fMRI switch rates
Better performances of BBS (p=0.044) in Tai Chi group were associated with the changes of visual network (VN). Improvements in UPDRS (p=0.023) and UPDRS-III (p=0.006) of PD patients were associated with enhancements of default mode network (DMN) after Tai Chi training. (Additional File 2-Table S2, Figure 2. E-H)
Cytokines
The levels of IL-1β (6 months: p= 0.013, 12 months: p=0.028), IL-5 (6 months: p= 0.028, 12 months: p=0.248), IL-7 (6 months: p= 0.032, 12 months: p=0.016) and IL-9 (6 months: p= 0.037, 12 months: p=0.019) were significantly downregulated in Tai Chi group compared with control group. (Additional File 2-Table S3)
Levels of IL-13 (6 months: p= 0.002, 12 months: p=0.005), PDGF-BB (6 months: p= 0.022, 12 months: p=0.011), MIP-1β (6 months: p= 0.003, 12 months: p=0.008) and MCP-1 (6 months: p= 0.032, 12 months: p=0.06) were stable in Tai Chi group but significantly increased in controls. The relatively stable levels of IL-13 (6 months: p= 0.019, 12 months: p=0.021) and MCP-1 (6 months: p= 0.0007, 12 months: p=0.022) were seen in Tai Chi group compared with brisk walking group. (Additional File 2-Table S3) In addition, upregulation and downregulation of MIP-1α were respectively seen in control group (p= 0.006) and brisk walking group (p= 0.029), while Tai Chi group had no changes at 6 months. But MIP-1α returned to the baseline level in three groups at 12 months. (Additional File 2-Table S3)
Higher level of GM-CSF was found in Tai Chi group while no change was seen either in control group (6 months: p= 0.005, 12 months: p=0.011) or in brisk walking group (6 months: p= 0.006, 12 months: p=0.014). Those changes above could be observed since 6 months and lasted to 12 months. (Additional File 2-Table S3)
Furthermore, by analyzing the association between changes of cytokines and changes of clinical presentations, we found that downregulation of IL-1β were positively related to improved BBS scores (p ≤0.031). (Additional File 2-Table S4)
Metabolomics
We tested 123 metabolites, of which 27 metabolites showed statistically changes. After Bonferroni correction, 11 metabolites were left significant. Fumaric acid, L-aspartic acid and pyroglutamic acid were decreased after Tai Chi training only at 6 months (p≤0.033). Downregulation of homocysteine and methionine sulfoxide, and upregulation of azelaic acid were seen in Tai Chi group both at 6 months (p≤0.005) and 12 months (p≤0.032). L-malic acid, 3-phosphoglyceric acid were downregulated, while L-fucose, adenosine and pipecolic acid were upregulated after Tai Chi training at 12 months (p≤0.028). (Additional File 2-S5)
We also found several associations between metabolites and clinical presentations. The L-malic acid, 3-phosphoglyceric acid, and adenosine were associated with changes of UPDRS (p≤0.043). The L-malic acid, L-fucose, and pipecolic acid were associated with the changes of UPDRS-III (p≤0.041). (Additional File 2-Table S6)
Pathway analysis showed group differences in arginine biosynthesis both at 6 months (Tai Chi v.s. Control: p=0.007; Tai Chi v.s. Brisk Walking: p=0.006) and 12 months (Tai Chi v.s. Brisk Walking: p < 0.001). (Additional File 2-Table S7, Additional File 3-Figure S1-3) In enrichment analysis, significant group difference was found in urea cycle both at 6months (Tai Chi v.s. Control: p=0.009; Tai Chi v.s. Brisk Walking: p=0.05) and 12 months (Tai Chi v.s. Brisk Walking: p < 0.001). (Additional File 2-Table S8, Additional File 3-Figure S4-6)
In association analysis, TCA cycle was correlated with BBS (p=0.037), UPDRS (p=0.002), UPDRS-III (p=0.014). Beta oxidation of very long chain fatty acids was relevant to UPDRS (p=0.033), UPDRS-III (p=0.033). (Additional File 2-Table S9)
HIP2 mRNA levels
The control group showed tendency of downregulation of HIP2 mRNA (p = 0.697). Compared with controls, the HIP2 mRNA level was elevated after Tai Chi training since 6 months (p<0.001) and lasted to 12 months (p<0.001). Tai Chi training seemed to be better in upregulating HIP2 mRNA level than brisk walking (p=0.277). (Additional File 3-Figure S7)
We found that the difference of UPDRS and UPDRS-III was associated with the change of HIP2 mRNA level after Bonferroni correction (p<0.005). Association between the difference of BBS and the change of HIP2 mRNA level was also detected, but it did not survive after Bonferroni correction. (Additional File 2-Table S10)