The metabolic changes in diabetics result in progressive retinopathy and influence corneal metabolism. Changes in corneal autofluorescence were demonstrated originating from mitochondrial flavoproteins and influenced by the metabolic changes in cornea in diabetics. The corneal autofluorescence was determined to evaluate its correlation with diabetic retinopathy using fluorophotometer in 25 healthy controls, 25 diabetic mellitus(DM) pationts without retinopathy, 25 background diabetic retinopathy(BDR)patients, 25 preproliferative diabetic retinopathy (PPDR) patients, and 25 proliferative diabetic retinopathy(PDR) patients. The mean values(mean +/- standard deviation in ng fluorescein/ml) were 13.9 +/- 1.9, 18.7 +/- 3.1, 19.6 +/- 2.3, 20.2 +/- 4.0, 24.3 +/- 4.2, respectively. The means of coreal autofluorescence values in diabetics were significantly higher than that of the healthy controls(p<0.001). The mean values in DM patients without retinopathy, BDR patients and PPDR patients did not differ significantly(p>0.05), but the mean value in PDR patients was significantly higher than those of the other 4 groups(p<0.001). These results indicate that measurement of corneal autofluorescence can play a supplementary role in diagnosing diabetic retinopathy.
Cornea ; Diabetic Retinopathy* ; Flavoproteins ; Humans ; Metabolism

No abstract available.
Diabetes Mellitus, Type 2/*blood ; Diabetic Nephropathies/*blood ; Diabetic Retinopathy/*blood ; Hemoglobins/*metabolism ; Humans ; Male

OBJECTIVEThis review focuses on the role of the large conductance calcium-activated potassium (BKCa) channels in diabetic vascular complications.

DATA SOURCESRelevant articles published in English or Chinese from 1981 to present were selected from PubMed. The search terms were "BKCa channels" and "diabetes". Important references from selected articles were also retrieved.

STUDY SELECTIONArticles regarding the role of BKCa channels in diabetic vascular complications and relevant mechanisms were selected.

RESULTSThe BKCa channels are abundantly expressed in vascular smooth cells and play an important role in regulation of vascular tone. Multiple studies indicated that the expression and function of BKCa channels are altered by different mechanisms in diabetic vascular diseases such as coronary arterial disease, cerebral arterial disease, and diabetic retinopathy.

CONCLUSIONBKCa channels may play an important role in diabetic vascular complications and may be an effective therapeutic target for relieving and reducing the burden of diabetic vascular complications.

Cerebral Arterial Diseases ; metabolism ; Coronary Artery Disease ; Diabetic Angiopathies ; metabolism ; Diabetic Retinopathy ; metabolism ; Humans ; Large-Conductance Calcium-Activated Potassium Channels ; metabolism

OBJECTIVETo investigate the expression of adiponectin and its receptors (AdipoRs) in the retina of normal mice and mice with type 1 diabetes mellitus (T1DM).

METHODSC57BL/6 mice were randomly divided into control group and streptozotocin-induced T1DM group. Two months after the modeling, the total protein and adiponectin protein expression in the retina and choroid were measured using BCA method and enzyme-linked immunosorbent assay, respectively. Quantitative RT-PCR was performed to detect the mRNA expressions of AdipoRs in the retina and choroid, and Western blotting was employed to examine the protein expressions of AdipoRs in the retina.

RESULTSAdiponectin and AdipoRs proteins were expressed in the retina and choroid in normal mice. The expressions of adiponectin and AdipoR1 were up-regulated in the retina of mice with T1DM while AdipoR2 expression exhibited no significant changes.

CONCLUSIONAdiponectin and AdipoR1 may play an important role in the evolvement of type 1 diabetic retinopathy.

Adiponectin ; metabolism ; Animals ; Diabetes Mellitus, Experimental ; metabolism ; Diabetes Mellitus, Type 1 ; metabolism ; Diabetic Retinopathy ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Receptors, Adiponectin ; metabolism ; Retina ; metabolism

BACKGROUND: The product of oxygen-free radicals inf1ict oxidative injuries on healthy cells. Antioxidants such as superoxide dismutase(SOD), glutathione peroxidase, and reduced glutathione(GSH) are present in almost all cells and play important roles in metabolism, transport, and cellular protection. We measured blood GSH levels in healthy controls and patients with non insulin dependent diabetes mellitus(NIDDM) for evaluation of the clinical usefulness of GSH. METHODS: Erythrocyte GSH levels were measured in fifty healthy controls and thirty NIDDM patients with diabetic retinopathies by Beutler's method. We also tested within-run precision, between-run precision, linearity and recovery rate to evaluate this method measuring erythrocyte GSH levels. RESULTS: The GSH levels (mean +/-SD) of NIDDM patients (5.03+/-0.67mumo1/Hb) were significantly lower than those of healthy control group (6.46+/-0.85mumo1/Hb)(P<0.001). The results of within-run precision and between-run precision when stored at 4degrees Cwere excellent (coefficient of variation were 2.79% and 2.42%, respectively), however, when stored at the room temperature the GSH levels were sharply declined. The linearity and recovery rate were acceptable. CONCLUSIONS: The prescision, linearity, and recovery rate of GSH measurement were excellent. The GSH levels in NIDDM patient group were reduced, and this probably contributes to the defective defense mechanism against increased oxidative stress. Additional measurement of other antioxidants such as superoxide dismutase and glutathione Peroxidase may be required to clarify the pathologic significance of glutathione metabolism in various diseases.
Antioxidants ; Diabetes Mellitus, Type 2 ; Diabetic Retinopathy ; Erythrocytes* ; Glutathione Peroxidase ; Glutathione* ; Humans ; Insulin ; Metabolism ; Oxidative Stress ; Superoxide Dismutase ; Superoxides

OBJECTIVETo investigate the expression of nitric oxide synthase (NOS) in the retina of 8-week-old diabetic rats, and explore the potential molecular mechanisms for the role of NO in diabetic retinopathy (DR).

METHODSRetinal gene expression profile of normal and 8-week-old diabetic rats was constructed with restriction fragment differential display polymerase chain reaction (RFDD-PCR). Bioinformatic analysis of the differentially expressed gene identified the genes coding for 3 subtypes of NOS, namely eNOS, nNOS and iNOS as the candidate genes related to DR, which was verified using semi-quantitative RT-PCR and immunohistochemistry.

RESULTSThe results of RFDD-PCR revealed down-regulated expression of eNOS and nNOS and up-regulated iNOS expression in diabetic rat retina. RT-PCR showed that the expression levels of eNOS and nNOS in diabetic rat retina were obviously lower than that in normal retina (0.23-/+0.03 vs 0.32-/+0.03 for eNOS, P<0.05; 0.25-/+0.02 vs 0.36-/+0.02 for nNOS, P<0.05), but the expression level of iNOS obviously higher (0.27-/+0.02 vs 0.20-/+0.03, P<0.05). Immunohistochemistry of healthy retina visualized eNOS-, nNOS- and iNOS-positive cells, all located in the inner nuclear layer (INL) and ganglion cell layer (GCL), and eNOS-positive cells were also found in vascular endothelium. In diabetic retina, the number of eNOS- and nNOS-positive cells was significantly lowered in comparison with normal rat retina (14.33-/+3.19 vs 22.13-/+3.60 for eNOS, P<0.05; 21.87-/+3.62 vs 34.40-/+7.09 for nNOS, P<0.05), but the number of iNOS-positive cells significantly increased (17.60-/+2.58 vs 11.73-/+2.70, P<0.05).

CONCLUSIONThe alterations in eNOS, nNOS and iNOS expression are associated with the deuelopmant and progression of DR.

Animals ; Diabetes Mellitus, Experimental ; metabolism ; Diabetic Retinopathy ; metabolism ; Gene Expression Profiling ; Gene Expression Regulation ; Nitric Oxide Synthase ; metabolism ; Polymerase Chain Reaction ; Rats ; Rats, Sprague-Dawley ; Retina ; metabolism ; pathology

Cell Hypoxia ; physiology ; Cells, Cultured ; Diabetic Retinopathy ; metabolism ; Female ; Humans ; Intercellular Adhesion Molecule-1 ; metabolism ; Male ; Middle Aged ; Monocytes ; metabolism ; Prospective Studies ; Vascular Endothelial Growth Factors ; metabolism

PURPOSE: To investigate the effect of bevacizumab (Avastin; Genentech, San Francisco, CA, USA) on vascular endothelial growth factor (VEGF) expression and inflammation in fibrovascular membranes in patients with proliferative diabetic retinopathy (PDR). MATERIALS AND METHODS: Fibrovascular membranes from 19 eyes of 18 patients with PDR were studied using immunohistochemistry and analyzed in the following 3 groups; group 1: 4 inactive PDR eyes, group 2: 10 active PDR eyes treated preoperatively with adjunctive intravitreal bevacizumab, group 3: five active PDR eyes not treated preoperatively with bevacizumab. Immunohistochemical staining for VEGF, CD31 and CD68 were done. RESULTS: The immunoreactivity to VEGF and CD 31-positive blood vessels was significantly higher in membranes from group 3 than group 1 (p = 0.007 for VEGF, 0.013 for CD 31-positive vessels). Intravitreal bevacizumab caused a reduction in VEGF expression and vascular densities in 4 out of 10 (40%) excised membranes from eyes with PDR. However, six membranes (60%) in group 2 still demonstrated relatively strong VEGF expression and high vascular density. Infiltration of macrophages was observed in 16 out of the 19 membranes, and the density of macrophages was increased in group 2 compared with group 1 (p = 0.043). CONCLUSION: Intravitreal bevacizumab injections caused some reduction in VEGF expression and vascular densities in a limited number of active PDR patients. A single intravitreal bevacizumab injection may not be enough to induce complete blockage of VEGF and pathologic neovascularization in active PDR patients. Repeated injections, panretinal photocoagulation and/or PPV may be necessary following intravitreal bevacizumab to reinforce the anti-VEGF effect of the drug.
Adult ; Angiogenesis Inhibitors/*therapeutic use ; Antibodies, Monoclonal/*therapeutic use ; Diabetic Retinopathy/*drug therapy/*metabolism ; Female ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Vascular Endothelial Growth Factor A/*metabolism

OBJECTIVETo investigate the impacts of steady high-glucose or fluctuated glucose conditions on glutamate (Glu) release in purified retinal ganglion cells (RGCs) cultured in vitro, and the effect of serum contained Chinese drugs for nourishing Shen and activating blood (S-NSAB) on it.

METHODSRGCs of neonatal SD rats were cultured by antibody combined two-step purified method in different conditions: the simulated normal condition, the steady high-glucose condition and the fluctuated glucose condition, and they were intervened with S-NSAB. Thereby, the experiment was carried out in 6 groups, i.e. the normal control group (A), the S-NSAB intervened group (B), the steady high-glucose cultured group (C), the steady high-glucose cultured and S-NSAB intervened group (D), the fluctuated glucose cultured group (E), and the fluctuated glucose cultured and S-NSAB intervened group (F). Content of Glu in the extracellular fluid was detected at 24, 48 and 72 h after intervention with a full-automatic biochemical analyzer. And the data obtained were statistically analyzed with SPSS 13.0 soft ware.

RESULTSRelease of Glu at 24 h after intervention in Group E (256.33 +/- 25.73 mg/L) was obviously higher than that in Group A and Group C (134.22 +/- 9.14 mg/L and 141. 17 +/- 22.13 mg/L, P < 0.05); at 24 h and 72 h in Group B (124.50 +/- 10.30 mg/L and 30. 17 +/- 2.97 mg/L) was obviously lower than in Group A respectively (P < 0.05); in Group D at 24 h (127.50 +/- 16.94 mg/L), 48 h (26.17 +/- 3.99 mg/L) and 72 h (27.67 +/- 3.49 mg/L) were lower than in Group C; in Group F at 24 h (228.33 +/- 18.41 mg/L) and 72 h (28.00 +/- 2.41 mg/L) were lower than in Group E respectively at the corresponding time points.

CONCLUSIONSFluctuated glucose condition could obviously increase the Glu release of RGCs, to cause extracellular large amount Glu accumulation, which induces the exciting neurotoxicity to RGCs and finally to aggravate the injury on cells. S-NSAB could reduce the Glu release to some extent in the steady-high or fluctuated glucose conditions, diminish the injury of RGCs from exciting neurotoxicity of Glu, and it might be one of the intervening pathways of Chinese drugs for NSAB in preventing and treating DRP.

Animals ; Animals, Newborn ; Cells, Cultured ; Diabetic Retinopathy ; prevention & control ; Drugs, Chinese Herbal ; pharmacology ; Glucose ; pharmacology ; Glutamic Acid ; metabolism ; Rats ; Rats, Sprague-Dawley ; Retinal Ganglion Cells ; cytology ; metabolism

OBJECTIVE: To investigate the effects of wogonoside on high glucose-induced dysfunction of human retinal microvascular endothelial cells (hRMECs) and streptozotocin (STZ)-induced diabetic retinopathy in rats and explore the underlying molecular mechanism. METHODS: HRMECs in routine culture were treated with 25 mmol/L mannitol or exposed to high glucose (30 mmol/L glucose) and treatment with 10, 20, 30, 40 μmol/L wogonoside. CCK-8 assay and Transwell assay were used to examine cell proliferation and migration, and the changes in tube formation and monolayer cell membrane permeability were tested. ROS, NO and GSH-ST kits were used to evaluate oxidative stress levels in the cells. The expressions of IL-1β and IL-6 in the cells were examined with qRT-PCR and ELISA, and the protein expressions of VEGF, HIF-1α and SIRT1 were detected using Western blotting. We also tested the effect of wogonoside on retinal injury and expressions of HIF-1α, ROS, VEGF, TNF-α, IL-1β, IL-6 and SIRT1 proteins in rat models of STZ-induced diabetic retinopathy. RESULTS: High glucose exposure caused abnormal proliferation and migration, promoted angiogenesis, increased membrane permeability (P < 0.05), and induced inflammation and oxidative stress in hRMECs (P < 0.05). Wogonoside treatment concentration-dependently inhibited high glucose-induced changes in hRMECs. High glucose exposure significantly lowered the expression of SIRT1 in hRMECs, which was partially reversed by wogonoside (30 μmol/L) treatment; interference of SIRT1 obviously attenuated the inhibitory effects of wogonoside against high glucose-induced changes in proliferation, migration, angiogenesis, membrane permeability, inflammation and oxidative stress in hRMECs. In rat models of STZ-induced diabetic retinopathy, wogonoside effectively suppressed retinal thickening (P < 0.05), alleviated STZ-induced retinal injury, and increased the expression of SIRT1 in the retinal tissues (P < 0.001). CONCLUSION Wogonoside alleviates retinal damage caused by diabetic retinopathy by up-regulating SIRT1 expression.
Animals ; Diabetes Mellitus/metabolism* ; Diabetic Retinopathy/metabolism* ; Endothelial Cells ; Flavanones ; Glucose/pharmacology* ; Glucosides ; Inflammation/metabolism* ; Interleukin-6/metabolism* ; Neovascularization, Pathologic/metabolism* ; Rats ; Reactive Oxygen Species/metabolism* ; Sirtuin 1/metabolism* ; Streptozocin/pharmacology* ; Vascular Endothelial Growth Factor A/metabolism*