[Application of indocyanine green iris angiography in the evaluation of anterior segment blood supply in different strabismus patients].

Objective: To evaluate the perfusion features of the anterior segment in patients with different types of strabismus. Methods: A cross-sectional study. Sixteen strabismus patients (16 eyes) who received the examination of iris indocyanine green angiography (ICGA) in Tianjin Eye Hospital from November 2016 to December 2021 were enrolled and divided into two groups according to whether they had a history of extraocular muscle injury/rectus muscle surgery. All patients underwent routine ophthalmic examinations. Angiographic images were obtained by the anterior segment camera, and indicators such as arm to iris circulation time, whole iris filling time, regression onset time, and complete regression time were recorded. The independent sample t test or Mann-Whitney U test was used to compare iris perfusion aspects of the two groups, and the Pearson/Spearman correlation tests was used to analyze the correlation of arm to iris circulation time and whole iris filling time with age and course of strabismus. Results: Among the 16 patients, there were 10 males and 6 females. The mean age was (49.2±13.2) years, and the course of strabismus ranged from 2 to 31 months. There were 7 patients in the group of without extraocualr muscle injury and 9 patients in the extraocular muscle injury/surgery group. There was no significant difference in age and course of strabismus between the two groups (both P>0.05). The arm to iris circulation time [M (Q1, Q3)] of the group without extraocular muscle injury and the group with extraocular muscle injury/surgery were 18 (18, 21) and 22 (20, 24) s, respectively. The average whole iris filling time was (13.86±1.95) and (12.22±3.60) s, respectively. There was no statistical significance between the two groups (both P>0.05). Correlation analysis showed that arm to iris circulation time was not correlated with age and course of strabismus (r=-0.033, -0.079; both P>0.05). And the whole iris filling time was not correlated with age and course of disease (r=0.057, -0.119; both P>0.05). The matrix scatter plots showed that in the group of extraocular muscle injury/surgery, there were three patients who were older than the average (49.2 years) and above the median of arm to iris circulation time (20 s) (two cases with the vertical muscle involved), meanwhile, there were three patients (all with the vertical muscle involved) whose course of strabismus was longer than 6 months and above the median of arm to iris circulation time, which were more than those in the group of without extraocular muscle injury (1 case, respectively). Conclusions: ICGA in patients with strabismus show that a history of injury to the extraocular muscle or surgical treatment beyond 2 months had no effect on iris perfusion. Age and course have no correlation with iris reperfusion. The vertical muscle involvement has more effects on the blood supply to the anterior segment.

[The protective effect of pigment epithelial-derived factor modified human umbilical cord mesenchymal stem cells on rats with diabetic retinopathy].

Objective: To investigate the effect of pigment epithelial-derived factor (PEDF) gene-modified human umbilical cord mesenchymal stem cells (MSC) on rats with diabetic retinopathy (DR). Methods: Experimental study. Human umbilical cord MSC were transfected by lentivirus packaging PEDF-MSC-green fluorescent protein (GFP) and GFP-MSC plasmid vectors, and the expression of PEDF and vascular endothelial growth factor (VEGF) was measured in the cell culture medium. Fifty adult male Sprague-Dawley rats were randomly divided into five groups: normal control group (group A), DR control group (group B), phosphate-buffered saline (PBS) treated group (group C), GFP-MSC treated group (group D) and PEDF-MSC-GFP treated group (group E), with 10 rats in each group. Streptozotocin was intraperitoneally injected to make early DR models. After four-month intervention, groups D and E were given intravitreal injection of GFP-MSC and PEDF-MSC-GFP; group C was given intravitreal injection of phosphate-buffered saline; groups A and B did not receive special treatment. The changes of retina in different groups were detected by hematoxylin and eosin staining, and the thickness of inner plexiform layer, inner nuclear layer and outer nuclear layer was measured by computer-based image analytical system. Immunohistochemistry was applied to observe PEDF and VEGF. Real-time quantitative polymerase chain reaction was used to detect the expression of PEDF and VEGF mRNA. Results: The expression of CD105, CD73 and CD90 was positive, while the expression of CD34, CD45, CD11b, CD19 and HLA-DR was negative. ELISA results showed that after transfection PEDF protein expression in the supernatant of PEDF-MSC (84.09±7.07) µg/L was higher than the control group (9.03±0.14) µg/L (P<0.05). At 2 weeks after intravitreal injection, green fluorescence was observed in the rat vitreous of groups D and E under a fluorescence microscope; no obvious green fluorescence was found in the retina. After 2 months of intravitreal injection, the thickness of inner plexiform layer in group E was significantly decreased; the thickness of inner nuclear layer and outer nuclear layer was higher (P<0.05). Immunohistochemical staining showed that 2 months after intravitreal treatment, the average optical density values of PEDF were improved, but the average optical density values of VEGF were decreased in group E (P<0.05). Real-time polymerase chain reaction showed that 2 months after treatment, the expression level of PEDF mRNA in group E was improved, but the expression level of VEGF mRNA was decreased (P<0.05). Conclusions: Intravitreal injection of PEDF-MSC could up-regulate the expression of PEDF and down-regulate the expression of VEGF in diabetic rats and may represent a novel candidate resource for cell therapy of DR nerve damage. (Chin J Ophthalmol, 2017, 53, 540-547).

[The protective effect of human umbilical cord mesenchymal stem cells-induced neural stem cells in the vitreous on the blood-retinal barrier in diabetic rats].

Objective: To investigate the effect of intravitreal injection of neural stem cells (NSC) induced from human umbilical cord mesenchymal stem cells, and to provide a theoretical basis for the clinical treatment of blood-retinal barrier damage due to diabetic retinopathy (DR). Methods: Experimental study. Sixty male Sprague-Dawley rats were randomly divided into control group, DR group and NSC group. Diabetic rats were induced by injection of streptozotocin, and the control rats were injected with an equal volume of solvent. Three months after the establishment of diabetic models, the NSC group was injected with 2 µl of NSC in the right vitreous, and the DR group was injected with 2 µl of phosphate-buffered saline. One month later, all the rats were sacrificed. The retinal vessels and leakage were examined with flat-mounted retinas. Vascular permeability was quantified by analyzing albumin leakage using the Evans blue (EB) method. Retina was examined by hematoxylin and eosin staining. Results: Retinal blood vessels of the control rats were normal, with no EB leakage outside the vessels. The background fluorescence was enhanced and focal leakage and focal dilated vessels were detected in the DR group. In the NSC group, background fluorescence was enhanced slightly and EB leakage area decreased significantly compared with the DR group. The average EB in control group, DR group and NSC group were (9.91±1.53), (24.67±2.26) and (12.85±2.58)µg/g, The EB leakage in the NSC group decreased significantly compared with the DR group (q=9.748, P<0.05). Pathological hematoxylin and eosin staining showed that the retinal layer structure was normal and clear in the control group, the retina was thin, the cell arrangement was in disorder and the nucleus was swelling in the DR group, the status of the NSC group was between the other two groups. Conclusions: Transferring human umbilical cord mesenchymal stem cells-induced NSC in vitro to diabetic rat models by intravitreal injection could reduce leakage of blood vessels and attenuate blood-retinal barrier breakdown induced by diabetes. (Chin J Ophthalmol, 2017, 53: 53-58).