Table 3.
Morphometric data obtained from human sural nerves at baseline and follow‐up of subjects with NGT, IGT and T2DM
| Parameters | NGT | NGT | IGT | T2DM | T2DM |
|---|---|---|---|---|---|
| Baseline n = 10 | Follow‐up n = 3 | Baseline n = 10 | Baseline n = 10 | Follow‐up n = 10 | |
| Myelinated fiber diameter (μm) | 7.3 (6.0–8.2) | 5.7 [5.5–7.3] | 6.0 (5.5–6.8) | 6.3 (5.7–6.6) | 6.0 (5.0–6.9) |
| Myelinated axon diameter (μm) | 3.9 (3.6–4.6) | 3.4 [3.1–3.8] |
3.5 (3.2–3.8) p < .03a |
3.4 (3.3–3.7) p < .03a |
3.6 (3.1–4.0) |
| Unmyelinated axon diameter (μm) | 1.1 (1.0–1.2) | 1.0 [0.96–1.2] | 1.1 (1.1–1.2) | 1.1 (1.1–1.2) |
0.98 (0.81–1.1) p = .038b |
| g‐Ratio | 0.58 (0.55–0.63) | 0.57 [0.53–0.64] | 0.60 (0.56–0.61) | 0.58 (0.57–0.60) | 0.63 (0.57–0.66) |
| Myelinated fiber density (no./mm2) | 5,662 (5,237–6,593) | 5,125 [4,172–6,656] | 6,384 (5,105–8,339) | 6,439 (4,512–9,767) |
2,839 (2,125–3,962) p = .005b p = .028a |
| Unmyelinated axon density (no./mm2) | 31,309 (22,708–38,190) | 33,373 [19,712–36,126] | 25,976 (24,686–35,793) | 22,708 (20,127–33,201) | 27,180 (20,557–34,922) |
| Autophagy density (no./mm2 in the nerve) | 7,225 (2,064–9,633) | 4,817 [3,441–6,881] | 4,645 (2,666–6,193) | 6,537 (5,160–11,182) | 4,473 [2,408–7,483] |
| Endoneurial capillary density (no./mm2) | 49.0 (34.3–54.9) | 43.9 (32.9–58.6) | 54.9 (21.5–77.8) | 61.2 (52.8–68.3) | 44.7 (31.0–74.6) n = 9 |
| Lumen area (μm2) | 19.7 (8.3–23.7) | 12.8 [8.3–28.0] | 5.5 (1.7–21.0) | 11.6 (1.9–19.4) | 8.5 (5.6–24.5) |
| Lumen area (%) | 10.2 (4.7–14.7) | 11.1 [8.0–13.0] | 6.9 (1.6–11.0) | 5.0 (1.1–9.8) | 5.5 (1.4–11.8) |
| EC area (μm2) | 28.9 (19.5–42.5) | 50.3 [32.9–70.9] | 28.2 (16.6–38.4) | 25.5 (22.9–39.0) |
40.9 (34.5–62.9) p ≤ .05b |
| EC area (%) | 14.2 (7.5–23.4) | 17.0 [11.8–26.1] | 23.6 (20.7–27.7) | 17.6 (11.3–29.3) | 21.6 (16.9–23.3) |
| EC number | 4.0 (4.0–4.0) | 4.0 [3.5–5.0] | 5.5 (4.4–6.3) | 4.0 (4.0–4.5) | 5.0 (4.8–5.1) |
| BM area (μm2) | 124.0 (88.7–155.3) | 114.5 [101.5–234.8] |
66.4 (48.3–92.5) p < .03a |
142.4 (60.1–164.2) | 133.1 (73.2–161.3) |
| BM area (%) | 66.5 (60.7–78.8) | 74.4 [63.3–76.4] | 68.5 (60.9–73.3) | 70.0 (63.0–79.5) | 69.9 (64.0–78.2) |
| Total diffusion barrier (μm2) | 144.5 (110.2–164.9) | 133.9 [94.7–267.4] |
90.4 (62.6–133.3) p < .08a |
152.4 (77.6–177.0) |
174.0 (114.8–214.6) p < .02b |
IGT, impaired glucose tolerance; n, number of patients; BM, basement membrane; EC, endothelial cell; TDB, total diffusion barrier; NGT, normal glucose tolerance.
Data are presented as median and (25th–75th percentiles) or when few numbers as [min–max].
Detailed nerve fiber morphometric analysis could not be performed at baseline due to poor fixation in one subject with NGT and one with T2DM. Blood vessel analysis at baseline was undertaken in eight subjects with NGT, nine subjects with IGT and 10 subjects with T2DM. At follow‐up, one patient with T2DM was excluded due to poor quality of the tissue. One subject with NGT and six subjects with IGT who had converted to T2DM as well as three of the patients with T2DM at baseline were recruited for the follow‐up study.
aVersus NGT (Kruskal–Wallis with post hoc analyses using Mann–Whitney at baseline and Mann–Whitney for the follow‐up).
bVersus baseline (Wilcoxon signed‐rank test).