Table 1.
Comparison of tissue engineered constructs and natural cartilage
| Parameter | Tissue engineered constructs
|
Natural cartilage** | ||
|---|---|---|---|---|
| At launch* | Mir-grown | Earth-grown | ||
| Culture time (months) | 3 | 7 | 7 | 0 |
| Chondrocyte function | ||||
| Sulfate incorporation (ng/μg DNA/day) | 80.8 ± 37.2 (3) | 88.9 ± 8.0 (3) | 83.4 ± 13.4 (3) | 332 ± 36.3 (7) |
| Proline incorporation (ng/μg DNA/day) | 82.0 ± 20.6 (3) | 93.0 ± 3.0 (3) | 87.9 ± 22.7 (3) | 205 ± 46.8 (7) |
| Construct composition | ||||
| Weight (mg wet) | 250 ± 38 (20) | 330 ± 25 (5) | 429 ± 14 (5) | 461 ± 72.8 (7) |
| Water (%) | 89.2 ± 0.89 (3) | 89.2 ± 0.31 (3) | 86.3 ± 0.53 (3) | 82.8 ± 0.93 (7) |
| Cells (% wet weight) | 0.64 ± 0.03 (3) | 0.40 ± 0.01 (3) | 0.46 ± 0.02 (3) | 0.66 ± 0.09 (7) |
| GAG (% wet weight) | 6.03 ± 0.84 (3) | 3.59 ± 0.22 (3) | 8.83 ± 0.93 (3) | 7.05 ± 0.56 (6) |
| Collagen (% wet weight) | 2.70 ± 0.75 (3) | 3.42 ± 0.17 (3) | 3.68 ± 0.27 (3) | 10.7 ± 0.91 (6) |
| Total of above components (% wet weight) | 98.6 ± 0.07 (3) | 96.6 ± 0.68 (3) | 99.3 ± 0.60 (3) | 101 ± 0.46 (6) |
| Type II collagen (% total collagen) | 91.6 ± 19.1 (2) | 78.0 ± 4.1 (4) | 75.3 ± 7.8 (4) | 90.3 ± 17.9 (5) |
| Mechanical behavior | ||||
| Aggregate modulus (MPa) | 0.108 ± 0.047 (2) | 0.313 ± 0.045 (4) | 0.932 ± 0.049 (3) | 0.949 ± 0.021 (3) |
| Hydraulic permeability (×10−15 m4/Ns) | 8.25 ± 1.94 (2) | 6.73 ± 3.02 (4) | 3.72 ± 0.167 (3) | 2.72 ± 0.641 (3) |
| Dynamic stiffness (MPa, 1 Hz) | 2.23 ± 0.12 (2) | 3.80 ± 0.39 (4) | 7.75 ± 0.30 (3) | 16.8 ± 1.14 (3) |
Data represent average ± standard deviation. Parentheses indicate the number of samples analyzed per group.
Statistical significance was assessed using ANOVA (α = 0.05) in conjunction with Tukey’s studentized range test. For each parameter, statistically significant differences between groups (P < 0.05) are denoted by different colors.
Wet weights at 3 months were those of the actual constructs used in 7-month Mir and Earth cultivations; all other parameters in this group were assessed using additional 3-month constructs from the same batch.
Wet weights for natural cartilage were scaled by a factor of five for better comparison with corresponding values measured for Earth-grown tissue engineered constructs.