Plasma metabolomic profiling of proliferative diabetic retinopathy.

BACKGROUND: Proliferative diabetic retinopathy (PDR), a sight-threatening retinopathy, is the leading cause of irreversible blindness in adults. Despite strict control of systemic risk factors, a fraction of patients with diabetes develop PDR, suggesting the existence of other potential pathogenic factors underlying PDR. This study aimed to investigate the plasma metabotype of patients with PDR and to identify novel metabolite markers for PDR. Biomarkers identified from this study will provide scientific insight and new strategies for the early diagnosis and intervention of diabetic retinopathy. METHODS: A total of 1024 patients with type 2 diabetes were screened. To match clinical parameters between case and control subjects, patients with PDR (PDR, n = 21) or those with a duration of diabetes of ≥10 years but without diabetic retinopathy (NDR, n = 21) were assigned to the present case-control study. Distinct metabolite profiles of serum were examined using liquid chromatography-mass spectrometry (LC-MS). RESULTS: The distinct metabolites between PDR and NDR groups were significantly enriched in 9 KEGG pathways (P < 0.05, impact > 0.1), namely, alanine, aspartate and glutamate metabolism, caffeine metabolism, beta-alanine metabolism, purine metabolism, cysteine and methionine metabolism, sulfur metabolism, sphingosine metabolism, and arginine and proline metabolism. A total of 63 altered metabolites played important roles in these pathways. Finally, 4 metabolites were selected as candidate biomarkers for PDR, namely, fumaric acid, uridine, acetic acid, and cytidine. The area under the curve for these biomarkers were 0.96, 0.95, 1.0, and 0.95, respectively. CONCLUSIONS: This study suggested that impairment in the metabolism of pyrimidines, arginine and proline were identified as metabolic dysregulation associated with PDR. And fumaric acid, uridine, acetic acid, and cytidine might be potential biomarkers for PDR. Fumaric acid was firstly reported as a novel metabolite marker with no prior reports of association with diabetes or diabetic retinopathy, which might provide insights into potential new pathogenic pathways for diabetic retinopathy.

[Diagnostic values of urinary netrin-1 and kidney injury molecule-1 for acute kidney injury induced by neonatal asphyxia].

OBJECTIVE: To investigate the values of urinary netrin-1 and kidney injury molecule-1 (KIM-1) in the early diagnosis of acute kidney injury (AKI) induced by neonatal asphyxia. METHODS: A total of 80 full-term neonates with asphyxia were enrolled (mild asphyxia: 34 neonates; severe asphyxia: 46 neonates). Forty normal full-term neonates were selected as the control group. Urinary samples were collected from the neonates in the three groups within 12 hours and 13-48 hours after birth. ELISA was applied to measure urinary levels of netrin-1 and KIM-1. Peripheral venous blood samples were also collected to measure serum creatinine (Scr) level. RESULTS: Compared with the control group, the asphyxia group had significantly higher urinary levels of netrin-1 and KIM-1 within 48 hours after birth and a significantly higher Scr level within 13-48 hours after birth (P<0.05). The neonates in the AKI group had significantly higher urinary levels of netrin-1 and KIM-1 and Scr level within 48 hours after birth than those in the non-AKI group (P<0.05). The areas under the receiver operating characteristic curve for urinary netrin-1 and KIM-1 levels within 12 hours after birth to predict AKI after asphyxia were 0.878 (95% CI: 0.775-0.981; P<0.01) and 0.899 (95% CI: 0.829-0.969; P<0.01), respectively. Any two indicators of urinary netrin-1 level, urinary KIM-1 level, and Scr level within 12 hours after neonatal asphyxia had a positive correlation (P<0.05). CONCLUSIONS: Urinary netrin-1 and KIM-1 levels increase significantly when neonates with asphyxia develop AKI. Urinary netrin-1 and KIM-1 can be used as indicators for the early diagnosis of AKI after asphyxia.

[Clinical characteristics of choroidal metastasis].

OBJECTIVE: To study the clinical characteristics of choroidal metastasis (CM) to promote the early diagnosis and differentiate from other choroidal tumors. METHODS: Retrospective clinical observational cases. All patients with choroidal metastasis underwent ophthalmologic examination including best corrected visual acuity (VA), slit-lamp examination, binocular indirect funduscopy, color photography, fundus fluorescein angiography (FFA), indocyanine-green angiography (ICGA), optical coherence tomography (OCT), A and B scan ultrasound examination, magnetic resonance image (MRI) as well as CT of the thorax, etc. RESULTS: Nine eyes of 5 patients with CM were examined. Unilateral choroidal involvement was present in 1 patient, bilateral in 4 cases. There were 1 case male and 4 case females. The age of these patients ranged from 31 to 56 years, median 45 years. Ocular symptoms included reduced vision in 4 patients and visual distortion in 1 patient. Visual acuity was 20/400- < 20/63 in four eyes; 20/63- < 20/30 in two eyes and >or= 20/30 in three eyes. The primary cancer site was in the lung in 3 patients, in the breast in 1 patient and in the stomach in 1 patient. Fundus characteristics: Typical CM was more often in the plateau-shaped than in the dome-shaped; yellow-white or mottled in color and associated with subretinal fluid and retinal detachment. The tumor was found in the macular area and juxtapapillary area in 6 eyes, in the area between the macula and the equator in 3 eyes. CM was solitary in 5 eyes and showed multiple lesions in 4 eyes. By FA the lesions showed mottled hyperfluorescence in early stage and leakage in late stage. By ICGA the lesion showed blocked fluorescence and hypofluorescence. Choroidal mass showed moderate irregular internal reflectivity in A-scan ultrasound. B-scan showed a plateau-shaped solid mass. MRI examination of the lesion revealed moderate short T1W and T2W signals. The cancer antigen increased to 16.28 and 4.95 microg/L in two cases. CA125 increased to 160.5 kU/L in one case. CONCLUSIONS: The choroid is the most common site for metastases. CM may precede the diagnosis of primary tumor. Evaluation of A, B scan ultrasound, CT of thorax and cancer antigen test may be important to exclude primary carcinoma from lung and breast in patients with yellow-white in color, plateau-shaped choroidal lesions, especially in both eyes, and without known metastatic diseases.

[Discussion of several problems in ophthalmic research in China].

Based on the manuscripts received by several ophthalmologic journals, major issues regarding current ophthalmic research aspects in China were analyzed and discussed, including the selection of project, the design of research, the choice of statistical treatments and the techniques of writing research manuscripts. This article provides suggestions for Chinese ophthalmologists to improve the quality of their research work.

[Measurement of macular edema in retinal vein occlusion using optical coherence tomography and its visual prognosis].

OBJECTIVE: To examine the type of macular edema in patients with retinal vein occlusion by using optical coherence tomography (OCT). To compare the sensitivity and specificity between OCT and fundus fluorescein angiography (FFA). To investigate the visual prognosis and risk factors in patients with cystoid macular edema (CME). METHODS: Ninety-one eyes of 90 patients with various types of retinal vein occlusion were examined by OCT and FFA. There were 54 cases male and 36 cases female. The age of these patients ranged from 20 to 74 years old and averaged (57.8 +/- 13.8) years old. Right eye was affected in 45 cases, and left eye in 46 cases (both eye in 1 case). Central retinal vein, hemicentral retinal vein and branch retinal vein were affected in 54, 9 and 28 eyes, respectively. The average follow-up period was 6.10 months. The sensitivity and specificity of OCT and FFA were measured. The visual prognosis and risk factors were analyzed. Macular central retinal thickness of 54 opposite normal eye was measured for comparison. RESULTS: (1) The classification of macular edema by OCT was cystoid macular edema in 71 eyes (78.0%); subretinal fluid in 14 eyes and laminar macular hole in 1 eye. The minimal and maximal height of intraretinal cystoid space was 94 microm and 1317 microm, respectively and averaged (668.18 +/- 245.58) microm. The minimal and maximal height of macular central retinal thickness of 54 opposite normal eye was 110 microm and 236 microm, respectively and averaged (154.09 +/- 21.85) microm. The maximal height of subretinal fluid space was 1377 microm or even beyond the detective limit of OCT. (2) The sensitivity of OCT for detection of CME was 98.6% and the specificity was 100%. The sensitivity of FFA was 86.1% and the specificity was 100.0%. (3) The visual prognosis of 61 eyes with CME follow-up over 3 months: The difference between the initial and final VA in branch retinal vein occlusion was statistically significant (P < 0.01), while no difference between initial and final VA in central and hemicentral retinal vein occlusion (P > 0.05). The factors affected visual prognosis of CME included the duration, the presence of hemorrhage in cystoid space and the severity of occlusion, etc. In CME under 3 months, the visual prognosis after therapy is better than that of before the therapy (P < 0.01); while in eyes with duration more than 3 months, no difference of vision could be detected before and after the therapy (P > 0.05). CONCLUSIONS: OCT is a safe, high-resolution, non-invasive, reliable and reproducible new examine method for detecting CME. The visual prognosis of CME is poor. It is possible that the visual prognosis can be improved by early detecting CME using OCT.

[Inhibition of lens epithelial cell cycle and PCNA mRNA expression by an antisense oligonucleotides complementary to the messenger RNA of proliferating cell nuclear antigen].

OBJECTIVE: To determine whether antisense oligonucleotides complementary to the messenger RNA of proliferating cell nuclear antigen (PCNA ASODN) inhibit the proliferation of bovine lens epithelial cell (BLEC) by changing the cell cycle and down-regulating the expression of PCNA mRNA and PCNA protein. METHODS: BLECs were cultured in vitro, and the second passage cells were used in this experiment. PCNA ASODN (30 micro mol/L), PCNA SODN (sense oligonucleotides, 30 micro mol/L), basic fibroblast growth factor (bFGF, 10 micro g/L), bFGF (10 ng/ml) + ASODN (30 micro mol/L), bFGF (10 micro g/L) + SODN (30 micro mol/L) were introduced respectively into the medium, and the same amount of PBS was added into the medium as a control. After 24 hours, the cell cycle and the PCNA expression were counted by flow cytometry, and the expression of PCNA mRNA was indicated by Northern ELISA hybridization. RESULTS: PCNA ASODN could decrease the rate of the cells of S phase and down-regulate the expression of PCNA mRNA and PCNA protein. Comparing with the control group, after 24 hours, the rate of cells of S phase was decreased from 15.67% to 7.96%, the expression of PCNA mRNA from 0.266 to 0.176 and the expression of PCNA protein from 55.27% to 12.32%. PCNA ASODN could also inhibit the proliferation of BLEC induced by bFGF, comparing with the bFGF group, the rate of cells of S phase was decreased from 23.4% to 19.9%, the expression of PCNA mRNA from 0.576 to 0.357 and the expression of PCNA protein from 76.4% to 35.48%. CONCLUSIONS: Our results demonstrate that the PCNA ASODN decreases expression of PCNA mRNA and PCNA protein, and stops the cell to enter and progress through S phase. These results provide an important impetus to initiate in vivo studies to determine the feasibility of antisense strategies in the prevention of posterior capsular opacification.

[The inhibitory effect of 8-chloroadenosine on tumor necrosis factor-induced proto-oncogene expression of retinal pigment epithelial cells].

OBJECTIVE: To investigate the inhibitory effect of 8-chloroadenodine (8-CLA) on tumor necrosis factor-alpha (TNF-alpha)-induced proto-oncogene expression in retinal pigment epithelial (RPE) cells. METHODS: Primary culture and subculture of health bovine RPE cells were established in vitro. RPE cells were treated with tumor necrosis factor TNF-alpha (13.3 mmol/L) with or without 8-CLA (16 micro mol/L) for 30 minutes or 3 hours, respectively. C-fos and c-myc mRNA expression in RPE cells was detected by Northern blot analysis. RESULTS: Normal RPE cells expressed c-fos and c-myc mRNA at a low level. After treatment with TNF-alpha, the expression of c-fos and c-myc mRNA was increased by 3.13 and 1.5 fold, respectively, as compared to untreated cells. 8-CLA decreased TNF-alpha-induced c-fos and c-myc mRNA expression by 25.0% and 29.0%, respectively. CONCLUSIONS: 8-CLA can inhibit TNF-alpha-induced c-fos and c-myc mRNA expression in RPE cells. These findings may be useful for exploring new drugs for inhibiting the growth-induced proliferation of RPE.