The effect of long-term hemodialysis on diabetic retinopathy observed by swept-source optical coherence tomography angiography.

BACKGROUND: Diabetes can cause chronic microvascular complications such as diabetic retinopathy (DR) and diabetic nephropathy (DN). DR and DN can lead to or exacerbate diabetic macular edema (DME). Hemodialysis (HD) is the main treatment method for patients with end-stage kidney disease (ESKD) secondary to DN. PURPOSE: The aim of this prospective cohort study was to determine the immediate effect of single HD session on retinal and choroidal thickness in DR patients with ESKD and the features of DR and the prevalence of DME in these patients who have received long-term HD. METHODS: Eighty-five eyes of 44 DR patients with ESKD who underwent long-term HD were examined by swept-source optical coherence tomography angiography (SS-OCTA). Based on OCTA images, the characteristics of DR and the prevalence of DME in these patients were analyzed. Changes in central retinal thickness (CRT), central retinal volume (CRV), subfoveal choroidal thickness (SFCT) and subfoveal choroidal volume (SFCV) within 30 min before and after single HD session were compared. CRT, CRV, SFCT and SFCV were compared before single HD session and before the next single HD session. RESULTS: There was no significant difference in the average CRT (251.69 ± 39.21 µm vs. 251.46 ± 39.38 µm, P = 0.286) or CRV (0.15 ± 0.62 µm vs. 0.15 ± 0.63 µm, P = 0.324) between before and after single HD session. After single HD session, SFCT (243.11 ± 77.15 µm vs. 219.20 ± 72.84 µm, P < 0.001) and SFCV (0.15 ± 0.10 µm vs. 0.13 ± 0.90 µm, P < 0.001) significantly decreased. There was no statistically significant difference in CRT (251.69 ± 39.21 µm vs. 251.11 ± 38.47 µm, P = 0.206), CRV (0.15 ± 0.62 µm vs. 0.15 ± 0.61 µm, P = 0.154), SFCT (243.11 ± 77.15 µm vs. 245.41 ± 76.23 µm, P = 0.108), or SFCV (0.15 ± 0.10 µm vs. 0.16 ± 0.10 µm, P = 0.174) before HD and before the next single HD session. On en face OCTA images, eighty-five eyes (100%) had retinal nonperfusion areas, foveal avascular zone (FAZ) enlargement, and abnormal retinal microvasculature. Based on cross-sectional OCTA images, retinal neovascularization (RNV) was confirmed in 42 eyes (49.41%), and intraretinal microvascular abnormalities (IRMAs) were detected in 85 eyes (100%). Seventeen eyes (20%) still had DME, all of which were cystoid macular edema (CME). Among eyes with DME, the epiretinal membrane (ERM) was present in 7 eyes (8.24%). CONCLUSIONS: For DR patients with ESKD who have undergone long-term HD, the choroidal thickness still changes significantly before and after single HD session, which may be related to short-term effects such as reduced blood volume and plasma osmotic pressure caused by single HD session. Although macular features seem to have stabilized in DR patients undergoing long-term dialysis, the DR of patients with ESKD should still be given attention.

Effect of radiation cross-linked collagen scaffold in alveolar ridge preservation of extraction socket.

This study aimed to evaluate the properties of radiation cross-linked collagen scaffold (RCS) and its efficacy for alveolar ridge preservation (ARP). RCS was prepared from collagen dispersion by electron beam irradiation and freeze-drying. The microstructure, swelling ratio, area alteration and mechanical properties of RCS were characterized. Fifty-four New Zealand rabbits performing incisor extraction on maxilla and mandible were randomly assigned into positive, sham operation or treatment groups. Micro-computed tomography (micro-CT) scans, performed after 1, 4, and 12 weeks of surgery, were to assess changes in ridge height at buccal and palatal side, in ridge width and in micromorphological parameters. Histological analysis accessed socket microarchitecture. The results showed that RCS had stable mechanical properties and morphologic features that provided a reliable physical support for ARP. Dimensional changes in treatment group revealed significantly greater vertical height at buccal (5.32 [3.37, 7.26] mm, p < .0001) and palatal (4.37 [2.66, 6.09] mm, p < .0001) side, and horizontal width at the maxilla (0.16 [0.04, 0.28] mm, p < .01) and mandible (0.33 [0.11, 0.54] mm, p < .01) than those in sham operation group after 12 weeks. The treatment group had advantage than positive group in vertical height preservation, quantitatively. The order and density of bone trabeculae were improved in treatment group. These findings indicated that RCS had the potential to serve as an effective scaffold for ARP.