Roles of elevated intravitreal IL-1β and IL-10 levels in proliferative diabetic retinopathy

Purpose:

To determine the roles of interleukin (IL)-1β and IL-10 in the vitreous of proliferative diabetic retinopathy (PDR).

Materials and Methods:

Vitreous samples were obtained from 26 eyes of 26 patients with PDR and from eight eyes of eight cases without PDR. The IL-1β and IL-10 concentration in the vitreous was measured by using an enzyme-linked immunosorbent assay (ELISA).

Results:

Levels of IL-1β and IL-10 in vitreous were higher in PDR patients compared with control group. And there was significantly negative correlation between IL-1β and IL-10 in control group (r = −0.795; P = 0.032), whereas there was no significant correlation in PDR group (r = 0.176; P = 0.391).

Conclusion:

Levels of IL-1β and IL-10 were upregulated in vitreous of PDR patients, and these two cytokines play roles in regulating the development and progression of PDR.     

Correlation of complement fragment C5a with inflammatory cytokines in the vitreous of patients with proliferative diabetic retinopathy

Purpose

To determine the vitreous concentration of complement fragment C5a in patients with proliferative diabetic retinopathy (PDR) and the relation between C5a and inflammatory cytokines including vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1).

Methods

Vitreous samples were obtained at the time of vitrectomy from 12 eyes of 11 PDR patients and from 11 eyes of 11 patients without diabetes with macular disease (controls). Vitreous and serum concentrations of human C5a, VEGF, and MCP-1 were quantified using FACS Caliber® flow cytometer.

Results

Vitreous concentration of C5a increased significantly in patients with PDR [median (range): 928.7 (46.6 to 3,319.4) pg/ml] compared with controls [58.7 (22.2 to 1,432.4) pg/ml; p?<?0.01]. In PDR patients, vitreous concentration of C5a correlated significantly with those of VEGF (p?<?0.05) and MCP-1 (p?<?0.05).

Conclusions

Our results suggest that C5a may play an important role in the pathogenesis of PDR and work in concert with inflammatory cytokines such as VEGF and MCP-1 in pathological angiogenesis.     

Increased levels of vascular endothelial growth factor in the aqueous humor of patients with diabetic retinopathy

Purpose:

This study aims to investigate the levels of aqueous vascular endothelial growth factor (VEGF) in diabetic patient groups in comparison to normal subjects, and to correlate elevated VEGF with the severity of diabetic retinopathy (DR).

Materials and Methods:

Aqueous samples were obtained from 78 eyes of 74 patients undergoing intraocular surgery and they were examined by the enzyme-linked immunosorbent assay. Color photographs, optical coherence tomography scans, and fluorescein angiography were used to evaluate patients preoperatively.

Results:

A strong statistical correlation was found to exist between the level of aqueous VEGF and the severity of DR (P < 0.001), whereas, the VEGF levels in a control group and a diabetic group without DR were not significantly different (P = 0.985). Aqueous VEGF levels were significantly elevated in patients with proliferative DR (PDR) as compared to the control group (P < 0.001), to diabetic patients without retinopathy (NDR) (P < 0.001), and to diabetic patients with nonproliferative DR (NPDR) (P < 0.001). The aqueous VEGF levels were significantly higher in patients with active PDR than in those with quiescent PDR (P = 0.001). On the other hand, a statistically insignificant (P = 0.065) correlation was found between elevated aqueous VEGF and the presence of macular edema in the NPDR group.

Conclusions:

VEGF was elevated in the aqueous humor of patients with DR compared to that in normal eyes. The aqueous VEGF level had a strong correlation with the severity of retinopathy along with a statistically insignificant difference in macular edema.     

Intraocular soluble intracellular adhesion molecule-1 correlates with subretinal fluid height of diabetic macular edema

Objective:

To investigate the correlations between aqueous concentrations of vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1), soluble intracellular adhesion molecule-1 (sICAM-1) and diabetic macular edema (DME).

Materials and Methods:

VEGF, MCP-1 and sICAM-1 concentrations in aqueous humor samples of 22 patients with DME and 23 patients with cataract of a control group were measured with solid-phase chemiluminescence immunoassay.

Results:

Aqueous VEGF (89.2 ± 58.5 pg/ml versus 48.5 ± 27.8 pg/ml, P = 0.006), MCP-1 (684.2 ± 423.4 pg/ml versus 432.4 ± 230.4 pg/ml, P = 0.019) and sICAM-1 (3213.8 ± 2581.6 pg/ml versus 260.2 ± 212.2 pg/ml, P < 0.001) all vary significantly between DME group and control group. Maximum height of submacular fluid measured by Optical coherence tomography (OCT) was significantly associated with aqueous sICAM-1 (r = -0.45, P = 0.034). The maximum height of macular thickness measured by OCT was not significantly associated with either VEGF (P = 0.300), MCP-1 (P = 0.320) or sICAM-1 (P = 0.285).

Conclusions:

Our results suggest that sICAM-1 may majorly contribute to the formation of subretinal fluid in DME patients and imply that MCP-1 and sICAM-1 may be the potential therapy targets, besides VEGF.     

Comparison of aqueous concentrations of angiogenic and inflammatory cytokines based on optical coherence tomography patterns of diabetic macular edema

Purpose:

The purpose was to compare aqueous inflammatory and angiogenic cytokine levels in diabetic macular edema (DME).

Materials and Methods:

Aqueous samples were obtained from 50 eyes with DME and 12 normal eyes (control group). DME was classified according to the morphologic pattern based on optical coherence tomography: Diffuse retinal thickening (DRT; n = 19), cystoid macular edema (CME; n = 17), or serous retinal detachment (SRD; n = 14). Aqueous samples were collected just before intravitreal injection and at the beginning of cataract surgery in the control group. Interleukin (IL)-6, IL-8, interferon-induced protein (IP)-10, monocyte chemotactic protein (MCP)-1, platelet-derived growth factor (PDGF)-AA, and vascular endothelial growth factor (VEGF) levels were measured by multiplex bead assay.

Results:

The IL-6, IL-8, IP-10, and PDGF-AA levels differed significantly among the three groups of DME (P = 0.014, P = 0.038, P = 0.021, and P = 0.041, respectively). However, there were no differences between groups in aqueous concentration levels of MCP-1 and VEGF (P = 0.205 and P = 0.062, respectively). IL-6 (P = 0.026) and IL-8 (P = 0.023) correlated positively with central foveal thickness (CFT) in the CME group. None of the cytokine levels correlated significantly with CFT in any of the DRT and SRD groups.

Conclusions:

Aqueous concentrations of cytokines varied according to the morphologic pattern of DME, which might explain the variable response to treatments such as intravitreal bevacizumab or triamcinolone injection.     

Increased intravitreous interleukin-18 correlated to vascular endothelial growth factor in patients with active proliferative diabetic retinopathy

Purpose

To determine the intravitreous levels of interleukin-18 (IL-18) and vascular endothelial growth factor (VEGF) in patients with proliferative diabetic retinopathy (PDR) and to ascertain their association with PDR activity.

Methods

Thirty eyes of 30 diabetic patients with PDR were divided into two groups (active PDR, n?=?17; quiescent PDR, n?=?13). Fifteen eyes of 15 non-diabetic patients (macular hole, n?=?9; epiretinal membrane, n?=?6) served as controls. All vitreous fluid samples were obtained during vitrectomy. IL-18 and VEGF were measured by enzyme-linked immunosorbent assay. Serum glycosylated hemoglobin as well as the basic demographic data was documented.

Results

Both IL-18 and VEGF levels were higher in patients with PDR than control (P?<?0 .01 and P?<?0 .01, respectively). Both IL-18 and VEGF in active PDR were higher than those in quiescent PDR (P?=?0.048 and P?=?0.03, respectively). A significant positive correlation (Spearman rank correlation coefficient (r _s)?=?0.502, P?=?0.005) between IL-18 and VEGF was observed in all PDR patients but not in the control. The correlation between VEGF and IL-18 was even stronger in the subgroup of active PDR (r _s?=?0.684; P?=?0.002), whereas no significant correlation was found in the subgroup of quiescent PDR (r _s?=?0.049; P?=?0.873).

Conclusions

Both intravitreous IL-18 and VEGF were elevated in patients with PDR, which were closely correlated in active PDR. IL-18 may contribute to retinal angiogenesis by acting together with or via VEGF, and become the potential therapeutic target for treatment of PDR.     

Expression of Pigment Epithelium-Derived Factor and Vascular Endothelial Growth Factor in Fibrovascular Membranes from Patients with Proliferative Diabetic Retinopathy

Purpose

The expression of pigment epithelium-derived factor (PEDF), a strong inhibitor of angiogenesis, has not been examined in human ocular fibrovascular membranes, to the best of our knowledge. The purpose of this study was to determine whether PEDF is expressed in the fibrovascular membranes in eyes of patients with proliferative diabetic retinopathy (PDR), and to compare the expression of PEDF with that of vascular endothelial growth factor (VEGF).

Methods

The expression of PEDF and VEGF in the fibrovascular membranes excised during vitreous surgery in eight cases of PDR was determined by immunohistochemistry.

Results

VEGF was strongly expressed in the endothelial cells of newly formed vessels in the fibrovascular membranes. In contrast, PEDF was weakly expressed in the endothelial cells and was prominently expressed in the extracellular matrix and fibrous tissue surrounding the new vessels.

Conclusions

Our results suggest that PEDF, along with VEGF, may modulate the formation of fibrovascular membranes in patients with PDR.?Jpn J Ophthalmol 2006;50:116–120 © Japanese Ophthalmological Society 2006     

Role of chemokines in the vitreous of proliferative diabetic retinopathy

PURPOSE: To investigate the role of chemokines in the pathogenesis of proliferative diabetic retinopathy (PDR). SUBJECTS AND METHODS: In total, 41 eyes of 38 patients undergoing vitrectomy were divided into two groups; PDR and non-PDR. The PDR group was comprised of 30 eyes, and the non-PDR group of 11 eyes. Vitreous specimens obtained at vitrectomy were centrifuged and separated into supernatants and cellular components. Concentrations of vascular endothelial growth factor(VEGF), interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1), and regulated upon activation, normal T cell expressed and secreted(RANTES) in the supernatants were determined by enzyme-linked immunosorbent assay(ELISA) or chemiluminescence enzyme immunoassay(CLEIA). Expression of VEGF in the cellular components was determined by immunohistochemistry. RESULTS: Vitreous levels of VEGF(p < 0.05), IL8 (p < 0.0001) and MCP-1 (p < 0.05) in the PDR group were significantly higher than in the non-PDR group. However, there was no significant difference in RANTES between the two groups. There was a significant correlation (p < 0.0001, r = 0.84) between vitreous IL-8 and MCP-1 levels in the PDR group. After immunohistochemical staining with antiVEGF monoclonal antibody, VEGF positivity was localized in polymorphonuclear leukocytes and monocytes of the cellular components of PDR vitreous specimens. CONCLUSIONS: These results indicate that chemokines are possibly involved in the recruitment of neutrophils and monocytes into the vitreous and that they play a role in the intraocular neovascularization characteristic of PDR.     

Soluble IL-6 Receptor in Vitreous Fluid of Patients with Proliferative Diabetic Retinopathy

Purpose

To identify the biological reaction of soluble interleukin-6 receptor (sIL-6R) in the vitreous of patients with proliferative diabetic retinopathy (PDR).

Methods

The subjects were 45 patients (45 eyes) with vitreoretinal diseases. The patients were divided into three groups: the PDR group comprised 28 patients (28 eyes) with PDR; the pre-proliferative diabetic retinopathy (PPDR) group comprised seven patients (seven eyes) with PPDR combined with diabetic macular edema; and the nondiabetic group comprised ten patients (ten eyes) with idiopathic macular hole or idiopathic epiretinal membrane. Vitreous samples were obtained at vitrectomy. sIL-6R, vascular endothelial growth factor (VEGF), and protein concentration in vitreous samples were determined by enzyme-linked immunosorbent assay (ELISA). sIL-6R levels in serum were also determined by ELISA in nine of the 28 patients with PDR and in six healthy volunteers as controls.

Results

In vitreous fluid, the levels of sIL-6R in the PDR group, PPDR group, and nondiabetic group were 612.7 ± 233.8 (mean ± SD), 746.3 ± 523.1, and 215.4 ± 98.3?pg/ml, respectively. Vitreous levels of sIL-6R in the PDR and PPDR groups were significantly higher than those in the nondiabetic group (PDR group, P < 0.0001; PPDR group, P < 0.01). In serum, the levels of sIL-6R were 39.38 ± 9.43?ng/ml in the PDR group and 22.84 ± 5.32?ng/ml in the control group. sIL-6R levels in serum in the PDR group were significantly higher than those in the control group (P < 0.01). A partial correlation analysis showed a significant correlation between the levels of sL-6R and VEGF in the vitreous in the PDR group (r = 0.34, P < 0.05).

Conclusions

We conclude that the level of sIL-6R in vitreous fluid can be considered as a biomarker of PDR.?Jpn J Ophthalmol 2007;51:100–104 © Japanese Ophthalmological Society 2007

     

Alteration of intraocular pigment epithelium-derived factor and vascular endothelial growth factor in patients with diabetic retinopathy

AIM:b To determine the aqueous, vitreous, serum levels of pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor (VEGF) in patients with proliferative diabetic retinopathy (PDR), and to speculate on the source of the change in concentration and to discuss its clinical significance. METHODS:b Forty-one eyes with proliferative diabetic retinopathy were included in the study, 16 of which were complicated by neovascularization of iris (NVI). Twenty-one eyes with idiopathic macular hole (MH) were as controls. The aqueous,vitreous, serum levels of PEDF and VEGF of all the groups were determined with ELISA. PEDF, VEGF and the levels in the three groups were compared with analysis of variance(ANOVA). The PEDF, VEGF concentrations in aqueous,vitreous and serum were analyzed with Pearson correlation test, and the correlation of PEDF and VEGF levels was also analyzed with Pearson correlation test. RESULTS:b The aqueous levels of PEDF decreased significantly in sequence in groups of control, PDR without NVI,PDR with NVI. VEGF levels increased coordinately. The similar findings existed in vitreous samples. The PEDF, VEGF levels in aqueous were not correlated significantly with those in serum, but correlated positively with those in vitreous. The intraocular levels of PEDF had a negative correlation to those of VEGF. CONCLUSION:b The reduction of intraocular PEDF level and elevation of intraocular VEGF level may play an important role in the occurrence and progression of PDR. In the development of PDR, the PEDF,VEGF levels in aqueous may be mainly effected by local pathological changes, as anti-angiogenic and pro-angiogenic factors, their unbalanced intraocular distribution may promote the angiogenesis of the iris and retina.     

Proinflammatory cytokines and angiogenic and anti-angiogenic factors in vitreous of patients with proliferative diabetic retinopathy and eales' disease

PURPOSE: To investigate the mechanism of angiogenesis in proliferative diabetic retinopathy (PDR) and Eales' disease (ED) on the basis of the levels of proinflammatory cytokines, angiogenic growth factor, and antiangiogenic factor in the vitreous humor. METHODS: Twenty-five patients with PDR, 10 patients with ED, and 25 with macular hole (MH) as control subjects were studied. The concentration of the proinflammatory cytokines interleukin-6 (IL-6), IL-8, IL-1 beta; chemokine-monocyte chemoattractant protein-1 (MCP-1); angiogenic factor-vascular endothelial growth factor (VEGF); and antiangiogenic factor-pigment epithelium derived factor (PEDF) in the vitreous fluid obtained from the eyes during vitrectomy were measured by sandwich enzyme linked immunosorbent assay (ELISA). RESULTS: IL-6, IL-8, MCP-1, and VEGF levels in the vitreous were significantly higher in PDR (P < 0.0001) and ED (P < 0.0001) than in MH patients. Conversely, the vitreous level of PEDF was significantly reduced in PDR (P < 0.0001) but not in ED. A significant correlation was observed between VEGF and IL-6 in ED patients. CONCLUSION: The authors demonstrate the importance of VEGF in retinal neovascularization of ED which is an idiopathic inflammatory venous occlusion. Further study is required to understand the interrelationship between VEGF and inflammatory cytokines in PDR and ED.     

Relationships between vitreous levels of soluble receptor for advanced glycation end products (sRAGE) and renal function in patients with diabetic retinopathy

Purpose

We investigated the relationship between vitreous levels of soluble receptor for advanced glycation end products (sRAGE) and vascular endothelial growth factor (VEGF) and renal function, and correlations between vitreous sRAGE levels and proliferative diabetic retinopathy (PDR) activity.

Methods

We examined 33 eyes from 33 patients with diabetes mellitus who underwent a vitrectomy (eight patients in the non-PDR [NPDR] group and 25 in the PDR group). Serum creatinine levels and estimated glomerular filtration rate (eGFR) were measured and classified according to the chronic kidney disease (CKD)-staging method. Enzyme-linked immunosorbent assay (ELISA) was performed to quantify vitreous sRAGE and VEGF levels.

Results

Vitreous sRAGE levels were significantly higher in PDR group compared to NPDR group (p = 0.00003). Vitreous sRAGE levels were significantly higher in patients with CKD stage 5 (end-stage renal failure or hemodialysis) than in patients with CKD stage 1 or 2 (p < 0.01) and 3 or 4 (p < 0.05), and were significantly correlated with eGFR (r = ? 0.490, p = 0.007) and creatinine levels (r = 0.484, p = 0.006). Within the PDR group, patients with low (<27 pg/mL) sRAGE levels required repeat vitreous surgeries for early postoperative vitreous hemorrhage significantly more frequently than those with high (≥27 pg/mL) sRAGE levels (p = 0.0067).

Conclusions

Vitreous sRAGE levels were significantly correlated with renal function, and low vitreous sRAGE levels in patients with PDR were associated with postoperative vitreous hemorrhage. Vitreous sRAGE may be a useful biomarker for renal dysfunction associated with diabetic retinopathy.

     

Effect of pan-retinal laser photocoagulation on plasma VEGF, endothelin-1 and nitric oxide in PDR

AIM: To study plasma levels of vascular endothelial growth factor (VEGF), endothelin-1(ET-1) and nitric oxide (NO) in patients with proliferative diabetic retinopathy (PDR) before and after pan-retinal photocoagulation (PRP). · METHODS: Forty patients (23 females and 17 males, mean age 48.5±12.2 years) with PDR without previous PRP therapy were studied. Blood samples were obtained before and 3 months after the last PRP session. Baseline (prelaser) plasma levels of VEGF, ET-1 and NO were compared with their levels in 30 healthy age- and sex- matched controls and also with plasma levels 3 months post-PRP. · RESULTS: Patients with PDR had significantly raised plasma VEGF (375±89ng/L), ET-1(20±5ng/L) and NO (135±53μmol/L) when compared with healthy control group (P <0.01). After PRP, there was a significant reduction in plasma VEGF (179±66ng/L), ET-1 (11±5ng/L) and NO (91±49μmol/L) levels at 3 months' follow-up but still significantly higher than healthy controls. · CONCLUSION: Patients with PDR demonstrate elevated VEGF, ET-1 and NO, which decrease after successful laser treatment.     

Elevation of serum apelin-13 associated with proliferative diabetic retinopathy in type 2 diabetic patients

AIM:To compare apelin-13, a ligand of G-protein-coupled receptor which has been shown to be involved in retinal angiogenesis, and vascular endothelial growth factor (VEGF) serum levels in type 2 diabetes mellitus (T2DM) with or without retinopathy, and to investigate the relationship between the serum concentration of apelin-13 and diabetes retinopathy.METHODS: Sixty-nine patients with T2DM were enrolled. Of the 69 patients, 16 had proliferative diabetic retinopathy (PDR group), 23 had non-PDR (NPDR group) and 30 had no retinopathy (T2DM group). Subjects’ information, including demographics, medical history, and use of medications were recorded. Their serum samples were collected for measuring the levels of C-reactive protein (CRP), serum lipid and glycosylated hemoglobin. Apelin-13 and VEGF serum levels were measured by enzyme-linked immunosorbent assay. Kruskal-Wallis test and one-way ANOVA were used to compare the differences among these groups. Chi-square test was used to assess categorical variables. Correlations between variables were investigated by Spearman rho correlation test and stepwise regression analysis. All statistical analyses were performed through SPSS 17.0 software.RESULTS:Sex, age, body mass index (BMI), blood pressure, CRP, hemoglobin A1c (HbA1c) have no significantly difference in the three groups. Serum level of apelin-13 was significantly elevated in PDR group as compared with T2DM group (P=0.041). Differences of VEGF serum concentration in the three groups were statistically significant (P=0.007, P=0.007 and P<0.001, respectively). Spearman rho correlation test showed that serum apelin-13 was positively correlated with BMI, serum triglycerides, VEGF, but not with age, duration of diabetes, blood pressure, CRP, HbA1c and total-cholesterol. Stepwise regression analysis showed that BMI also significantly associated with serum apelin-13 (P=0.002), while VEGF and serum triglycerides were irrelevant.CONCLUSION: This study elucidated a positive association of apelin-13 serum level with PDR, but not with VEGF. Apelin-13 may influence the promotion of PDR but unrelated with VEGF.     

PDR行玻璃体手术前注射雷珠单抗或曲安奈德后玻璃体腔内细胞因子的变化

目的：比较增生型糖尿病视网膜病变(PDR)行玻璃体切割术前用雷珠单抗或曲安奈德玻璃体腔内注射前后玻璃体腔内细胞因子的变化。

方法：前瞻性研究。将2015-05/2017-02我院收治的PDR患者88例112眼纳入研究。依照随机方法分为行玻璃体切割术前玻璃体腔注射0.5mg/0.05mL雷珠单抗组(43例57眼)、行玻璃体切割术前玻璃体腔注射4mg/0.1mL曲安奈德组(45例55眼),两组患者分别在玻璃体腔注射药物前抽取0.5mL玻璃体液后于玻璃体腔内注射雷珠单抗或曲安奈德。注药后7d行玻璃体切割术术前再次抽取玻璃体液0.5mL。采用双抗酶联免疫吸附试验(ELISA)测定玻璃体液的胎盘生长因子(PIGF)。用Luminex200液相芯片分析系统检测单核细胞趋化蛋白1(MCP-1)、单核细胞趋化蛋白3(MCP-3)、白介素-6(IL-6)、白介素-8(IL-8)、血小板源性生长因子-AB/BB(PDGF-AB/BB)和血管内皮生长因子-A(VEGF-A)浓度。

结果：雷珠单抗组玻璃体腔内PIGF与VEGF-A水平注射后较注射前均明显降低,而IL-6、IL-8水平增高(PIGF：65.36±15.16 vs 19.42±6.34pg/mL; VEGF-A：315.16±14.34 vs 21.32±2.54pg/mL,IL-6：37.32±4.04 vs 52.42±5.32pg/mL; IL-8：111.723±21.32 vs 198.73±19.03pg/mL,P<0.001)。而MCP-1、MCP-3及PDGF-AB/BB的水平无明显变化(P>0.05)。曲安奈德组玻璃体腔内PIGF水平显著增加(74.28±17.34 vs 136.12±15.34pg/mL,P<0.05)。而MCP-1水平明显减少(2789.32±143.54 vs 2038.21±105.34pg/mL,P<0.05)。MCP-3、IL-6、IL-8、PDGF-AB/BB、VEGF-A表达均无明显改变(P>0.05)。两组患者治疗后进行对比,雷珠单抗注射后玻璃体中PIGF、VEGF-A含量明显低于曲安奈德注射后含量(P<0.01),IL-8、MCP-1水平则显著增加(P<0.05)。此外,雷珠单抗组术中出血情况明显低于曲安奈德组(P<0.05)。

结论：玻璃体腔注射雷珠单抗能显著降低PIGF、VEGF-A表达,同时促进IL-6、IL-8水平增加; 而玻璃体腔内注射曲安奈德能减少MCP-1表达,促进PIGF水平增加。     

Angiogenesis-related cytokines in serum of proliferative diabetic retinopathy patients before and after vitrectomy

AIM: To evaluate serum concentrations of angiogenesis-related cytokines in proliferative diabetic retinopathy (PDR) before and after vitrectomy. METHODS: Serum samples were collected from 30 PDR patients with varying severity before and after vitrectomy. Serum concentrations of vascular endothelial growth factor (VEGF), pigment epithelium-derived factor (PEDF), interleukin-8 (IL-8) and interferon-inducible protein-10 (IP-10) were determined by enzyme-linked immunosorbent assays (ELISA). RESULTS: Serum concentrations of VEGF, PEDF, IL-8 and IP-10 were significantly higher in PDR patients than that in controls, respectively (P<0.05). VEGF concentration decreased significantly in postoperative samples than that in preoperative samples (P<0.05). The concentrations of PEDF, IL-8 and IP-10 did not exhibit significant changes after vitrectomy. CONCLUSION: Elevated cytokines levels in serum may be diagnostically useful in PDR. Angiogenesis-related cytokines play important roles in the development of PDR, and would instruct the risk assessment of pathogenetic condition in PDR patients.     

Sub-lytic C5b-9 induces functional changes in retinal pigment epithelial cells consistent with age-related macular degeneration

Purpose

There is evidence for complement dysfunction in age-related macular degeneration (AMD). Complement activation leads to formation of the membrane attack complex (MAC), known to assemble on retinal pigment epithelial (RPE) cells. Therefore, the effect of sub-lytic MAC on RPE cells was examined with regard to pro-inflammatory or pro-angiogenic mediators relevant in AMD.

Methods

For sub-lytic MAC induction, RPE cells were incubated with an antiserum to complement regulatory protein CD59, followed by normal human serum (NHS) to induce 5% cell death, measured by a viability assay. MAC formation was evaluated by immunofluorescence and FACS analysis. Interleukin (IL)-6, -8, monocytic chemoattractant protein-1 (MCP-1), and vascular endothelial growth factor (VEGF) were quantified by enzyme-linked immunosorbent assay (ELISA). Intracellular MCP-1 was analysed by immunofluorescence, vitronectin by western blotting, and gelatinolytic matrix metalloproteinases (MMPs) by zymography.

Results

Incubation of RPE cells with the CD59 antiserum followed by 5% NHS induced sub-lytic amounts of MAC, verified by FACS and immunofluorescence. This treatment stimulated the cells to release IL-6, -8, MCP-1, and VEGF. MCP-1 staining, production of vitronectin, and gelatinolytic MMPs were also elevated in response to sub-lytic MAC.

Conclusions

MAC assembly on RPE cells increases the IL-6, -8, and MCP-1 production. Therefore, sub-lytic MAC might have a significant role in generating a pro-inflammatory microenvironment, contributing to the development of AMD. Enhanced vitronectin might be a protective mechanism against MAC deposition. In addition, the increased expression of gelatinolytic MMPs and pro-angiogenic VEGF may be associated with neovascular processes and late AMD.     

Vitreous levels of pigment epithelium-derived factor and vascular endothelial growth factor: implications for ocular angiogenesis

PURPOSE: Pigment epithelium-derived factor (PEDF) has been demonstrated to suppress ocular angiogenesis in several animal models. In this study, we sought to measure the levels of PEDF and vascular endothelial growth factor (VEGF) in the vitreous of patients with and without ocular neovascular disorders. DESIGN: Case-control study of patients undergoing intraocular surgery for a variety of neovascular and nonneovascular conditions. METHODS: Vitreous samples were collected from 65 eyes of 65 patients with no neovascular disorder (n = 24), choroidal neovascularization (n = 9), active proliferative diabetic retinopathy (n = 16), and inactive proliferative diabetic retinopathy (n = 16). The levels of VEGF and PEDF in these vitreous samples were determined by enzyme-linked immunosorbent assay. RESULTS: The VEGF levels were at or below the level of detectability in the reference and choroidal neovascularization groups. The VEGF levels were significantly elevated in both the active and inactive PDR groups, and significantly higher in the active PDR group as compared with the inactive PDR group. The PEDF levels, which were present at relatively high concentrations in all groups, were higher in patients with active PDR compared with the control and choroidal neovascularization groups. CONCLUSIONS: High levels of immunoreactive PEDF are present in the vitreous of individuals with or without ocular neovascularization, but PEDF levels are significantly higher in patients with active PDR compared with patients with choroidal neovascularization or nonneovascular retinal diseases. Although these results do not preclude the possibility that endogenous PEDF helps to modulate ocular neovascularization, they do not support ischemia-induced downregulation of PEDF as a mechanism for such modulation.     

VEGF expression and cell apoptosis in NOD mouse retina

AIM: To investigate retinal vascular endothelial growth factor (VEGF) level and retinal cells apoptosis in the early stage of diabetic NOD mouse retina. METHODS: Animals were divided into non-diabetes group, (control) (2-, 4-, 6-, 8- and 12-week sub-groups, n=30) and diabetes group (2-, 4-, 6-, 8- and 12-week sub-groups, n=30). Enzyme-linked immunosorbent assay (ELISA) was performed to detect VEGF level in both serum and retina. Transmission electron microscope method was used to examine retinal cell apoptosis. RESULTS: Compared with the control group, VEGF levels in serum and retina were increased significantly in the NOD group (12 weeks: 4.9±0.4μg/g vs 0.19±0.1μg/g in serum sample, P<0.01; 165±9μg/g vs 17±5μg/g in retinal sample, P<0.01). There exists a positive correlation between serum VEGF and retinal VEGF levels in the early diabetic NOD mice (γ=0.9902, P=0.001). The number of the cells apoptosis in the ganglion cells and endothelium can also been found increased significantly in the NOD group (P<0.01). CONCLUSION: The high VEGF expression may be contributed to increased retinal cells apoptosis. Many factors associated with retinal VEGF expression might involve in the early diabetes stage.     

Impact of early rise of intraocular pressure on visual outcome following diabetic vitrectomy

Objective:

The objective was to study the incidence and risk factors for an early rise in intraocular pressure (IOP) following pars plana vitrectomy (PPV) for proliferative diabetic retinopathy (PDR) and to correlate its impact on visual outcome.

Materials and Methods:

This was a longitudinal prospective study. IOP and best corrected visual acuity (BCVA) for 73 cases of PDR (52 males and 21 females) who underwent PPV were recorded at day 1, week 1, and months 1, 3, and 6. Risk factors for the early IOP rise, defined as IOP ≥ 30 mmHg at day 1, were evaluated using cross-tabulation and the t-test.

Results:

Mean IOP at day 1 was 21.8 ± 9.8 mmHg with 15 cases (20.5%) having an early rise in IOP. Risk factors for the early IOP rise included intraoperative fibrovascular frond removal (P = 0.003), lens removal (P = 0.043), and intraoperative vitreous bleed (P = 0.008). The early rise in IOP was also associated with consistently raised IOP (P = 0.02), defined as IOP > 21 mmHg during first three consecutive follow-up visits. Further, difference in BCVA at 6 months among the two groups, i.e., with and without an early IOP rise was statistically significant (3.11 ± 1.52 logMAR vs. 2.11 ± 1.49 logMAR; P = 0.025).

Conclusion:

An early rise in IOP is a significant risk factor which compromises the visual outcome of patients undergoing diabetic vitrectomy.