Table 1.
GAG content of various negatively charged tissues is represented as μg GAG/mg dry tissue weight. Average fixed charge density (FCD) of tissues is calculated using . For sulfated GAGs, MW ∼ 458 g/mol and −2 moles of charge per mole of GAG disaccharide unit is assumed [236]. For HA, MW (of repeating disaccharide unit) ∼ 401 g/mol and −1 mole of charge per mole of repeating unit is assumed. Tissue dry weight was converted to wet weight by using their respective water content. Cartilage, ligament/tendon, meniscus, nucleus pulposus, vitreous humor, mucus and skin water content were assumed 80 %, 80 %, 70 %, 80 %, 99 %, 95 % and 70 %, respectively. Additionally, percentage composition of different types of GAGs (chondroitin sulfate (CS), keratan sulfate (KS), heparan sulfate (HS), dermatan sulfate (DS) and hyaluronic acid (HA)) in each tissue is presented.
| Tissue | GAG content (μg GAG/mg dry tissue) | Average Fixed Charge Density (mM) | Types of GAGs |
|---|---|---|---|
| Cartilage | 100 to 300 [221,222] | −170.0 [223] | CS (80 %) KS (5–20 %) HA (1–10%) [49] |
| Synovial fluid | 28.8 [224] | −8.8 [224] | HA (97%) CS (3 %) [224] |
| Ligaments and tendons | 2 to 35 depending on region [91] | Ligament: −17.9 [82] Tendon: −6.6 [82] |
CS (16–56 %) DS (20 %–66 %) [225] |
| Meniscus | 39 to 9 from inner to outer region [226] | −51.5 [53] | CS (60 %) DS (20 %) KS (15 %) HA (3 %) [227] |
| Nucleus pulposus | 100 to 400 [228] | −138.2 [229] | CS (67 %) KS (21 %) HA (5%) [230] |
| Vitreous humor | 23 [231] | −0.6 [231,232] | HA (96.2 %) CS (3.5 %) HS (0.3%) [231] |
| Gastric mucosal membrane | 19.6–23.4 [233] | −4.4 [233] | DS (45 %) CS (20 %) HS (19 %) HA (16 %) [234] |
| Skin | 3.4 [235] | −2.5 [235] | DS (46.7 %) HA (46 %) HS (3.9 %) CS (3.3 %) [235] |