Table 2.
Characteristics of assays used to assess collagen turnover.
| Biomarker | Specifications | Applicable in | Technical References |
|---|---|---|---|
| COL I ASSAYS | Interstitial matrix | ||
| C1M | Recognizes a fragment of the α1 chain of COL I generated by MMP-2, 9 and 13 |
Plasma (P-C1M) Urine (U-C1M) |
27 |
| PRO-C1 | Recognizes an internal epitope in the N-terminal pro-peptide of COL I | Plasma (P-PRO-C1) | 26 |
| COL III ASSAYS | Interstitial Matrix | ||
| C3A | Degradation fragment of COL III generated by ADAMTS-4 | Plasma (P-C3A) | |
| C3C | Degradation fragment of COL III generated by cathepsin B, L, S and K |
Plasma (P-C3C) Urine (U-C3C) |
22 |
| C3M | Degradation fragment of COL III generated by MMP-9 |
Plasma (P-C3M) Urine (U-C3M) |
23– 25 |
| sauC3M | Degradation fragment of COL III (sandwich ELISA) generated by MMP-9 | Urine (U-sauC3M) | |
| PRO-C3 | Recognizes the cleavage site of the N-terminal pro-peptide of COL III |
Plasma (P-PRO-C3) Urine (U-PRO-C3) |
19– 21 |
| COL VI ASSAYS | Interface between interstitial matrix and basement membrane | ||
| C6M | Degradation product of the α1 chain of COL VI generated by MMP-2 | Plasma (P-C6M) | 33, 34 |
| PRO-C6 | Recognizes the C-terminal of α3 chain in COL VI which is released upon deposition in the ECM |
Plasma (P-PRO-C6) Urine (U-PRO-C6) |
28, 29 |
| COL IV ASSAYS | Glomerular basement membrane | ||
| C4M | Degradation fragment of the α1 chain of COL IV generated by MMP-12 |
Plasma (P-C4M) Urine (U-C4M) |
18 |
| C4Ma3 | Degradation fragment of the α3 chain of COL IV generated by MMP-12 | Plasma (P-C4Ma3) | 18 |
| PRO-C4 | Internal epitope in the 7S domain of type IV collagen | Plasma (P-PRO-C4) | 16, 17 |