Adrenomedullin and leptin levels in diabetic retinopathy and retinal diseases

PURPOSE: Proliferative and vascular retinal diseases are important cause of irreversible blindness. Consistent features of these diseases are endothelial dysfunction and angiogenesis. Adrenomedullin (ADM) is a multifunctional vasorelaxant peptide. Leptin is a recently discovered metabolic peptide that regulates energy metabolism in human. In the present study, we aimed to investigate the possible roles of adrenomedullin and leptin in the pathophysiology of diabetic and proliferative diseases. METHODS: Ten patients with proliferative diabetic retinopathy (57.1 years, 5 female and 5 male) and 8 patients (51 years, 5 female and 3 male) with other retinal diseases including macular hole and epiretinal membrane were included in this study. All the patients had undergone pars plana vitrectomy for complications of the diseases. Vitreous samples were collected by vitreous tap during the vitrectomy. Adrenomedullin analysis was made by using reverse-phase high-performance liquid chromatography (HPLC). Leptin was measured by enzyme-linked immunosorbent assay (ELISA). Body mass index (BMI) [weight (kg)/height (m2)] was calculated for each group. The Mann-Whitney U test was used for statistics. RESULTS: The age, gender ratio and BMI were not substantially different between the two groups. The mean vitreous adrenomedullin levels (63.9+/-7.1 pmol/l) were significantly higher (p<0.05) in group I than in group II (34.25+/-3.0 pmol/l). Leptin levels in vitreous (4.54+/-1.6 ng/ml) were also significantly higher (p<0.05) in patients with diabetic retinopathy than in those without diabetes (1.83+/-0.5 ng/ml). CONCLUSION: Increased adrenomedullin and leptin levels in vitreous humor might be a possible newly associated factor in the course of vascular and proliferative retinal diseases.     

Vitreous leptin levels in retinal disease

BACKGROUND/AIMS: The purpose of this study was to investigate the relationship between vitreous leptin levels and retinal diseases. METHODS: Levels of vitreous leptin were evaluated in proliferative diabetic retinopathy (PDR) and a variety of other retinopathies including: macular disease, neovascular maculopathies, primary retinal detachments, and vascular occlusive disease. RESULTS: In patients with PDR (N=7), the average vitreous level of leptin (37.4 ng/ml) was significantly higher than that in patients with PVR (<1.0 ng/ml, P<0.05). Vitreous leptin level in patients with PVR or macular disease (N=18), with or without diabetes, was not significantly different from the control subjects who had retinal detachment only (N=7). CONCLUSION: The results show that the leptin level in vitreous taps is elevated in PDR. We suggest that leptin plays an active role in PDR.     

TIMP-1 and TIMP-2 Levels in Vitreous and Subretinal Fluid

To understand the role of tissue inhibitors of metalloproteinase-1 and -2 (TIMP-1 and TIMP-2) in intraocular diseases, levels of TIMP-1 and TIMP-2 were measured by enzyme immunoassay in 47 patients with various ocular diseases: in subretinal fluid of 7 patients with rhegmatogenous retinal detachment and in vitreous of 12 patients with proliferative diabetic retinopathy, 4 with proliferative vitreoretinopathy, 2 with vitreous hemorrhage due to branch retinal vein occlusion, 12 with idiopathic macular hole, 3 with retinal detachment due to high-myopic macular hole, 4 with macular epiretinal membrane, and 3 with choroidal neovascular membrane due to age-related macular degeneration. TIMP-1 levels were significantly higher in subretinal fluid than in vitreous fluid with any diseases (P < 0.0001, Mann-Whitney U test). TIMP-1 levels in vitreous fluid of the eyes with proliferative diabetic retinopathy and proliferative vitreoretinopathy were higher than those in vitreous with other diseases (P < 0.0001). In contrast, TIMP-2 levels were not elevated in the subretinal fluid and vitreous. TIMP-1, but not TIMP-2, was secreted into the subretinal space in rhegmatogenous retinal detachment, and also into the vitreous in eyes with proliferative diseases, suggesting that TIMP-1 would play a specific role in the process of these diseases.     

Elevated vitreous nitric oxide levels in patients with proliferative diabetic retinopathy

PURPOSE: The aim of this study was to determine nitric oxide levels in the vitreous of patients with proliferative diabetic retinopathy. METHODS: Using the spectrophotometric method based on Griess reaction, we measured levels of nitrite, the stable product of nitric oxide, in the vitreous of 21 eyes of 21 patients who underwent vitrectomy for the treatment of proliferative diabetic retinopathy with tractional retinal detachment, prospectively. Three samples were excluded from the study because of blood contamination. The control group was made up of vitreous samples from 15 eyes of 15 normal cadavers and five eyes of five patients who were undergoing vitrectomy for macular hole surgery.RESULTS: Nitrite levels were 0. 524 +/- 0.27 microM and 0.383 +/- 0.17 microM in the vitreous of patients with proliferative diabetic retinopathy of diabetes type I and type II, respectively. In 15 cadaver eyes and five vitreous samples from patients who underwent macular hole surgery, nitrite levels were below the detection limit (less than 0.08 microM). There was no significant difference between nitrite levels in patients with type I and type II diabetes (P =.56), whereas there was a significant difference between diabetes groups and controls (P <. 00001).CONCLUSION: Vitreous nitric oxide levels are elevated in patients with proliferative diabetic retinopathy with tractional retinal detachment. Nitric oxide may play a role in the pathogenesis of proliferative diabetic retinopathy.     

瘦素在增殖性糖尿病性视网膜病变和增殖性玻璃体视网膜病变中的表达

目的 通过检测瘦素在增殖性糖尿病性视网膜病变（proliferative diabetic retinopathy,PDR）和增殖性玻璃体视网膜病变（proliferative vitreous retinopathy,PVR）中的表达,探讨瘦素在PDR、PVR发生、发展过程中可能的调节机制。方法 分别用免疫组织化学染色的方法和酶联免疫吸附实验检测30例PDR患者、20例PVR病变患者眼内视网膜前膜中瘦素的表达,以及患者的血清、眼前房水、玻璃体液中瘦素的浓度。用Chi－Square Tests统计学方法分析和比较PDR、PVR与对照组之间瘦素表达的差异。结果 免疫组织化学染色结果：30例PDR患者中,有18例患者眼内视网膜前膜的瘦素受体呈阳性表达,阳性率为60%,与对照组比较,差异有统计学意义;20例PVR患者中,有3例患者眼内视网膜前膜的瘦素受体呈阳性表达,其中2例为血管纤维性视网膜前膜,1例为细胞纤维性视网膜前膜,阳性率为15%,与对照组比较,差异无统计学意义。ELISA结果：检测30例PDR患者的血清、眼前房水、玻璃体液中瘦素的浓度,与对照组之间差异有统计学意义（P＜0.05）;检测20例PVR患者的血清、眼前房水、玻璃体液中瘦素的浓度,与对照组之间差异无统计学意义（P＞0.05）。结论 瘦素可能主要是通过促进新生血管的生成参与到增殖性糖尿病性视网膜病变的发生、发展中,与增殖性玻璃体视网膜病变的发生、发展无明显相关性。     

Management of proliferative diabetic retinopathy

Proliferative diabetic retinopathy is characterized by neovascularization originating from the retina and/or optic disk in patients with diabetes mellitus. The role of vascular endothelial growth factor appears to be central in the pathogenesis of proliferative diabetic retinopathy. Advanced glycation end products are important in the development of vitreous abnormalities in proliferative diabetic retinopathy. The majority of the neovascular membranes are adherent to the posterior vitreous cortex. When the posterior hyaloid exerts traction, the edges of the neovascular complex are pulled forward, resulting in vitreous hemorrhage. Tractional and/or rhegmatogenous retinal detachments can occur. The Diabetic Retinopathy Study demonstrated the ability of panretinal photocoagulation to reduce the rate of severe visual loss by 50% for eyes with high-risk characteristics, defined as neovascularization originating from the optic disk > 1/3 disk diameter, any neovascularization originating from the optic disk with hemorrhage, and neovascularization originating from the retina with vitreous hemorrhage. The Early Treatment Diabetic Retinopathy Study showed that patients with type II diabetes mellitus who were older than 40 with severe nonproliferative diabetic retinopathy (defined as hemorrhages in four quadrants, venous beading in two quadrants, or intraretinal microvascular abnormalities in one quadrant) also benefited from early panretinal photocoagulation. The Diabetic Retinopathy Vitrectomy Study showed that early vitrectomy (within 6 months of onset of vitreous hemorrhage) was associated with better results in type I diabetes mellitus patients only. The goals of vitreous surgery are to remove the vitreous, including the posterior hyaloid, and to relieve traction from fibrovascular tissue. Delamination and segmentation techniques have been used in the excision of fibrovascular growth on the internal limiting membrane and extending into the vitreous. Panretinal photocoagulation is an integral component of vitrectomy for proliferative diabetic retinopathy. Anti-vascular endothelial growth factor agents may be used in addition to laser as an adjunct to reduce the risk of neovascularization. Vitrectomy surgery may have intraoperative and postoperative complications, including cataract, anterior hyaloidal fibrovascular proliferation, fibrovascular ingrowth, retinal detachment, and recurrent vitreous hemorrhage. Visual potential depends on the preoperative and postoperative status of the macula, as well as on retinal perfusion and the health of the optic nerve. With the improvement in instruments, techniques, and drugs, the results of vitrectomy in proliferative diabetic retinopathy are improving.     

严重PDR玻璃体切割术后雷珠单抗注射的效果观察

目的：对严重增殖性糖尿病视网膜病变的患者行玻璃体切割术后行雷珠单抗注射的效果观察。方法：回归性分析。12例严重增殖性糖尿病视网膜病变患者(12眼)接受睫状体平坦部玻璃体切割术,同时给予硅油、惰性气体或者平衡液的玻璃体腔填充。在手术结束的同时给予雷珠单抗的玻璃体腔注射。结果：随访时间平均为2.75 mo。这12眼中分别包括玻璃体积血(1眼);玻璃体积血伴纤维血管化增生(1眼);玻璃体积血伴牵拉性视网膜脱离(3眼);纤维血管化增生伴牵拉性视网膜脱离(2眼);玻璃体积血伴新生血管性青光眼伴牵拉性视网膜脱离(1眼);玻璃体积血伴纤维血管化增生伴牵拉性视网膜脱离(2眼);玻璃体积血伴纤维血管化增生伴新生血管性青光眼伴牵拉性视网膜脱离(1眼);玻璃体积血伴牵拉性孔源性视网膜脱离(1眼)。12眼中,8眼行玻璃体腔硅油填充,2眼行惰性气体填充,2眼行平衡液填充。所有的患者之前均未接受任何治疗。视网膜脱离复位率为10/10(100%)。1眼术后出现前房积血。9眼术后最佳矫正视力较术前提高,2眼无明显变化,1眼较术前下降。 OCT检查显示8眼术后未见黄斑水肿。结论：玻璃体切割术后雷珠单抗注射对严重增殖性糖尿病视网膜病变患者有明显的治疗效果：手术成功率明显提高;患者视力显著提高;糖尿病黄斑水肿的发生概率减少;术中及术后并发症的发生率降低。     

Pars-plana-Vitrektomie bei diabetischer Retinopathie Vom pathogenetischen Prinzip zur operativen Strategie

Diabetic retinopathy is the most important manifestation of diabetic eye disease. There are retinopathy, maculopathy, pathology of the vitreoretinal interface, and tractional retinal detachment. The development of surgical approaches based on pathogenetic ideas are shown. The beneficial effect of pars plana vitrectomy for persisting and recurrent vitreous hemorrhage, epiretinal fibrovascular proliferation, and retinal detachment is discussed. The surgical skills and experiences in diabetic eyes are stressed.     

Gelatinase B in proliferative vitreoretinal disorders

Purpose: To investigate whether gelatinases A and B are involved in the pathogenesis of proliferative vitreoretinal disorders.Methods: In a prospective study of 101 consecutive patients, vitreous and paired serum samples were obtained from 38 patients with rhegmatogenous retinal detachment complicated by proliferative vitreoretinopathy, 25 patients with rhegmatogenous retinal detachment with no proliferative vitreoretinopathy, and 38 patients with proliferative diabetic retinopathy. Gelatinase activities were determined by quantitative zymography.Results: All vitreous samples contained comparable levels of the constitutive gelatinase A. Inducible gelatinase B was detected in eight (32%) of 25 vitreous samples from patients with rhegmatogenous retinal detachment with no proliferative vitreoretinopathy (mean ± SD, 319.5 ± 521.0 scanning units), in 17 (44.7%) of 38 vitreous samples from patients with proliferative vitreoretinopathy (560.6 ± 718.9 scanning units), and in 34 (89.5%) of 38 vitreous samples from patients with proliferative diabetic retinopathy (1,707.2 ± 1,220.3 scanning units). The incidence of detection of gelatinase B in proliferative diabetic retinopathy cases was significantly higher than it was in rhegmatogenous retinal detachment with no proliferative vitreoretinopathy and proliferative vitreoretinopathy cases (P < .001). Gelatinase B levels in the vitreous samples of patients with proliferative diabetic retinopathy were higher than the levels found in patients with rhegmatogenous retinal detachment with no proliferative vitreoretinopathy and in patients with proliferative vitreoretinopathy (P = .0152). Gelatinase A was detected in all the tested sera, whereas none of the tested paired serum samples contained detectable gelatinase B activity.Conclusions: Gelatinase B may play an important role in extracellular matrix degradation associated with neovascularization in proliferative diabetic retinopathy.     

Ⅱ型增殖性糖尿病视网膜病变患者行玻璃体切除地机与术后视力 …

探讨Ⅱ型增殖性糖尿病视网膜病变合并严重玻璃本出血或合并血管纤维增殖引起的视网膜牵拉性视网膜脱离情况下,进行玻璃全切除术的手术时机。     

A Case of Proliferative Sarcoid Retinopathy with Sarcoid Nodules in Tissue Obtained During Vitrectomy

Background: In previous studies, intraocular proliferative tissues obtained from proliferative sarcoid retinopathy cases during vitrectomy have been examined histopathologically. However, there is no report of identification of sarcoid nodules in examined tissues. We performed vitrectomy for a case of proliferative sarcoid retinopathy with extensive proliferative changes. Histopathologically, sarcoid nodules were identified in the fibrovascular membranes.Case: A 25-year-old man was treated for sarcoid uveitis in the right eye by his local ophthalmologist. Lens aspiration was performed for complicated cataract. He was referred to our hospital with vitreous opacity and traction retinal detachment which occurred after the surgery.Findings: The vitreous opacity was so severe that details of the fundus were not visible. Traction retinal detachment was suspected from findings of B-mode echography. Vitrectomy was performed, and total retinal detachment due to contraction of the fibrovascular membrane around the optic disc and posterior pole was observed. Sarcoid nodules were identified histopathologically in fibrovascular membranes obtained during vitrectomy.Conclusion: In proliferative sarcoid retinopathy cases, sarcoid lesions may be one of the causes of fibrovascular membrane formation.     

A case of proliferative sarcoid retinopathy with sarcoid nodules in tissue obtained during vitrectomy

BACKGROUND: In previous studies, intraocular proliferative tissues obtained from proliferative sarcoid retinopathy cases during vitrectomy have been examined histopathologically. However, there is no report of identification of sarcoid nodules in examined tissues. We performed vitrectomy for a case of proliferative sarcoid retinopathy with extensive proliferative changes. Histopathologically, sarcoid nodules were identified in the fibrovascular membranes. CASE: A 25-year-old man was treated for sarcoid uveitis in the right eye by his local ophthalmologist. Lens aspiration was performed for complicated cataract. He was referred to our hospital with vitreous opacity and traction retinal detachment which occurred after the surgery. FINDINGS: The vitreous opacity was so severe that details of the fundus were not visible. Traction retinal detachment was suspected from findings of B-mode echography. Vitrectomy was performed, and total retinal detachment due to contraction of the fibrovascular membrane around the optic disc and posterior pole was observed. Sarcoid nodules were identified histopathologically in fibrovascular membranes obtained during vitrectomy. CONCLUSION: In proliferative sarcoid retinopathy cases, sarcoid lesions may be one of the causes of fibrovascular membrane formation.     

Results of vitrectomy for proliferative diabetic retinopathy

The authors treated 1007 eyes with vitrectomy for complications of proliferative diabetic retinopathy. Indications for surgery were: vitreous hemorrhage, 353 eyes (35%); traction retinal detachment, 360 eyes (36%); combined traction-rhegmatogenous retinal detachment, 172 eyes (17%); and other progressive fibrovascular proliferation 122 eyes (12%). During the study period, the frequency of vitreous hemorrhage as an indication for surgery decreased from 42 to 25%, and other progressive fibrovascular proliferation increased from 5 to 22%. The frequency of traction and traction/rhegmatogenous retinal detachments did not change. The results of surgery varied according to the indication. Seventy-nine percent of eyes with vitreous hemorrhage obtained final vision of 5/200 or better. Similar results were obtained in 64% of eyes with traction detachment, 56% of eyes with rhegmatogenous detachment, and 81% of eyes with progressive fibrovascular proliferation. The percentage of eyes achieving final vision of 20/100 or better are as follows: vitreous hemorrhage, 48%; traction detachment, 27%; rhegmatogenous detachment, 24%; and progressive fibrovascular proliferation, 46%. The success rate improved in each anatomic category during the last 3 years of the study.     

Vitrectomy in the management of diabetic eye disease.

Vitrectomy techniques including endolaser photocoagulation allow visual rehabilitation in many eyes that are otherwise untreatable. Discerning the indications and timing for diabetic vitrectomy is increasingly important as the treatment of complications of diabetic retinopathy continues to undergo modification and redefinition. The most common indications for diabetic vitrectomy include: 1) severe nonclearing vitreous hemorrhage; 2) traction retinal detachment recently involving the macula; 3) combined traction and rhegmatogenous detachment; 4) progressive fibrovascular proliferation; and 5) rubeosis iridis and vitreous hemorrhage for eyes in which the media opacity has prevented adequate laser photocoagulation. Other less common indications in selected cases include dense premacular hemorrhage, ghost cell glaucoma, macular edema with premacular traction, cataract preventing treatment of severe, proliferative diabetic retinopathy, anterior hyaloidal fibrovascular proliferation, and fibrinoid syndrome with retinal detachment. The rationale and surgical objectives are discussed and results are summarized.     

Sealing of retinal breaks with metal tacks. Evaluation of a new procedure in retinal re-attachment surgery

Metal retinal tacks were used in 18 patients with complicated retinal detachments, such as giant tears (3 cases), severe proliferative vitreoretinopathy (PVR) (7 eyes) and diabetic traction and rhegmatogenous detachment (8 cases). All eyes had undergone vitreous microsurgery, including excision or segmentation of epiretinal membranes, fluid-air (SF6) or silicone oil exchange. Retinal breaks and the cut edges of retinotomies and retinectomies were successfully sealed by metal tacks. Retinal re-attachment was achieved in 9 cases and partial re-attachment in another 5 eyes (follow-up 3-6 months). Retinal tears in diabetic macular detachment associated with extensive epiretinal fibrovascular membranes were also successfully sealed despite persisting traction. Our first experience indicates that the closing of retinal breaks with metal tacks is a major step forward in retinal re-attachment surgery.     

Clinical factors related to the aqueous levels of vascular endothelial growth factor and hepatocyte growth factor in proliferative diabetic retinopathy

PURPOSE: To investigate clinical factors related to the aqueous humor levels of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) in patients with proliferative diabetic retinopathy (PDR). METHODS: Undiluted aqueous humor was obtained during ocular surgery from 46 eyes of 46 patients and the levels of growth factors were measured using enzyme-linked immunosorbent assays. VEGF and HGF levels were compared with the number of photocoagulation. VEGF and HGF levels in patient groups stratified according to the existence of vitreous hemorrhage, retinal detachment, and fibrovascular membrane were analyzed. And clinical parameters associated with the growth factors were determined by multiple regression analysis. RESULTS: The levels of VEGF decreased significantly as the extent of photocoagulation increased and showed significant positive correlation with the existence of vitreous hemorrhage. There was no significant correlation between VEGF levels and the existence of fibrovascular membrane and traction retinal detachment. The levels of HGF also decreased significantly as the extent of photocoagulation increased, but increased significantly when fibrovascular membrane existed. There were no significant correlations between HGF levels and the existence of vitreous hemorrhage and traction retinal detachment. Concerning systemic conditions, each growth factor has no significant correlation with duration and type of diabetes mellitus, the treatment regimen, the control of hemoglobin A1C, and the existence of hypertension or renal dysfunction. CONCLUSION: The therapeutic effect of panretinal photocoagulation on PDR might be partly exerted by reduction of the levels of VEGF and HGF in ocular fluid. Since the clinical parameters associated with VEGF were different from those associated with HGF, these growth factors might influence the progression of retinopathy in different ways.     

Incidence of rhegmatogenous retinal detachment after vitrectomy in eyes of diabetic patients

PURPOSE: To assess the incidence of rhegmatogenous retinal detachment (RRD) after pars plana vitrectomy (PPV) among diabetic patients with complications of proliferative diabetic retinopathy. METHODS: Ninety-three eyes of diabetic patients-who underwent PPV with or without intraocular gas tamponade for complications of proliferative diabetic retinopathy-were reviewed retrospectively. Indication for vitrectomy was vitreous hemorrhage in 80 patients (86.1%), tractional retinal detachment in 3 (3.2%), and vitreous hemorrhage associated with tractional retinal detachment in 10 (10.7%). RESULTS: Four (4.3%) of 93 eyes developed an RRD after vitrectomy. The primary reason for vitrectomy was recurrent or nonresolving vitreous hemorrhage. The retina was attached with one additional surgical procedure in two of these eyes; the other two had to undergo a third operation before attachment was achieved. CONCLUSION: RRD occurs in a small percentage of patients after PPV with or without gas tamponade for vitreous hemorrhage or tractional retinal detachment caused by proliferative diabetic retinopathy. Thorough postoperative follow-up is important to make early diagnosis and intervention possible.     

进展型增生性糖尿病视网膜病变玻璃体 切割手术的价值与意义

目的了解有不同并发症的进展型增生性糖尿病视网膜病变眼进行玻璃体手术的结果。方法将患有Ⅰ、Ⅱ型糖尿病进展型增生性糖尿病视网膜病变的314只眼分为玻璃体积血合并局限牵拉性视网膜脱离组;广泛纤维血管膜合并牵拉性视网膜脱离组;牵拉孔源混合性视网膜脱离组;玻璃体积血视网膜脱离合并老年性白内障行玻璃体手术联合白内障摘除及人工晶状体植入组,分别进行回顾性分析。结果玻璃体积血合并局限牵拉性视网膜脱离组中Ⅰ、Ⅱ型糖尿病患 者手术后获得0.1以上视力的分别占39.4%和66.7%,广泛纤维血管膜合并牵拉性视网膜脱离组中Ⅰ、Ⅱ型糖尿病患者手术后获得0.1以上视力的分别占31.6%和51.6%,牵拉孔源混合性视网膜脱离组手术后获得0.1以上视力者占31.6%,玻璃体积血视网膜脱离合并老年性白内障行玻璃体手术联合白内障摘除及人工晶状体植入组手术后获得0.1以上视力者占62.5%。首要的术中 并发症是医源性视网膜裂孔,术后视力丧失的主要原因包括新生血管性青光眼、视网膜脱离和视网膜中央动脉阻塞。结论玻璃体切割手术联合全视网膜光凝术,能有效地改善进展性糖尿病视网膜病变患者的视力。(中华眼底病杂志,2001,17:171-174)     

糖尿病患者玻璃体积血病因分析

目的:分析糖尿病患者玻璃体出血的原因,为相关疾病的诊治提供资料。方法:对2004-04/2007-06我科收治的126例(142眼)玻璃体积血的糖尿病患者情况进行回顾性分析。结果:增殖性糖尿病视网膜病变(proliferative diabetic reti-nopathy,PDR)122眼(85.9%),视网膜静脉阻塞(retinal vein occlusion,RVO)10眼(7.0%),视网膜裂孔(retinal hole,RH)6眼(4.2%),玻璃体后脱离(posterior vitreous detachment,PVD)4眼(2.8%);PDR组患者对侧眼糖尿病视网膜病变显著重于其余各组。结论:增殖性糖尿病视网膜病变是糖尿病患者玻璃体出血的主要原因,此外,视网膜静脉阻塞、视网膜裂孔和玻璃体后脱离也占有一定比例;通过对侧眼情况的评估,有助于玻璃体出血原因的判断。     

Intravitreous leptin concentrations in patients with proliferative diabetic retinopathy

BACKGROUND: Previous studies have demonstrated that leptin is an angiogenic factor, and an increase in intravitreous leptin concentrations in diabetic patients with proliferative diabetic retinopathy (PDR) has also been described. The aim of the present study was to investigate the source of intravitreal leptin and to determine whether it is related to PDR activity. METHODS: Serum and vitreous fluid samples were obtained simultaneously at the time of vitreoretinal surgery from 25 patients with PDR and 32 nondiabetic patients with nonproliferative ocular diseases (controls). Both groups were matched by age, sex, and body mass index. Leptin levels were determined by ELISA. RESULTS: We did not observe any significant differences in vitreal levels of leptin between diabetic patients with PDR and controls (4.22 [2.6-9.7] versus 3.49 [1.9-9.7] ng/mL; P = not significant). Leptin concentrations were lower in vitreous fluid than in serum samples from diabetic patients with PDR (P < 0.001) and controls (P < 0.001). A direct correlation between serum and vitreous leptin concentrations was detected in diabetic patients with PDR (r = 0.60; P = 0.01) and controls (r = 0.51; P = 0.01). Finally, we did not observe any relationship between intravitreous leptin levels and PDR activity. CONCLUSIONS: The intraocular production of leptin is not critically involved in the etiopathogenesis of PDR. In addition, our results suggest that serum diffusion is a relevant source of leptin in vitreous fluid.