losartan-potassium and Diabetic-Retinopathy

Diabetic retinopathy (DR) is characterized by ischemia, hypoxia, and angiogenesis. Erythropoietin (EPO), an angiogenic hormone, is upregulated in DR, and the association of EPO genetic variants with DR is still uncertain, as conflicting results have been reported. Therefore, we performed a case-control study followed by a meta-analysis to investigate whether the rs1617640, rs507392, and rs551238 polymorphisms in EPO gene are associated with DR.. The case-control study included 1042 Southern Brazilians with type 2 diabetes (488 without DR and 554 with DR). Eligible studies for the meta-analysis were searched from electronic databases up to June 1, 2021. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for five genetic inheritance models.. The minor alleles of the EPO polymorphisms had nearly the same frequency in all groups of patients (35%), and no association was detected with DR in the case-control study. The meta-analysis included 14 independent sets of cases and controls with 9117 subjects for the rs1617640 polymorphism and nine independent sets with more than 5000 subjects for the rs507392 and rs551238 polymorphisms. The G allele of the rs1617640 polymorphism was suggestively associated with DR under the dominant (OR = 0.82, 95% CI: 0.68-0.98), heterozygous additive (OR = 0.82, 95% CI: 0.69-0.97), and overdominant (OR = 0.88, 95% CI: 0.79-0.97) models. In the subgroup analyses, the G allele was also suggestively associated with proliferative DR (PDR), non-proliferative DR (NPDR), and DR (PDR + NPDR) among patients with type 1 diabetes (T1DM) or non-Asian ancestry. After considering the Bonferroni correction for multiple comparisons, the G allele remained associated with NPDR and DR in T1DM. Regarding the rs507392 and rs551238 polymorphisms, no association was found between these variants and DR.. Our findings provide additional support to EPO as a susceptibility gene for DR, with the rs1617640 polymorphism deserving further investigation.

Topics: Case-Control Studies; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Erythropoietin; Gene Frequency; Genetic Predisposition to Disease; Genotype; Humans; Polymorphism, Single Nucleotide

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes mellitus (DM). DR is complex and the term encompasses several clinical subtypes of diabetic eye disease, including diabetic macular edema (DME), the most frequent cause of central vision loss in DR patients. Both genetic and environmental factors contribute to the pathophysiology of DR and its subtypes. While numerous studies have identified several susceptibility genes for DR, few have investigated the impact of genetics on DME susceptibility. This review will focus on the current literature surrounding genetic risk factors associated with DME. We will also highlight the small number of studies investigating the genetics of response to antivascular endothelial growth factor (anti-VEGF) injection, which is used to treat DME.

Topics: Aldehyde Reductase; Angiogenesis Inhibitors; Apolipoproteins E; Bevacizumab; Diabetic Retinopathy; Erythropoietin; Eye Proteins; Genetic Predisposition to Disease; Humans; Macular Edema; MicroRNAs; Nerve Growth Factors; Nitric Oxide Synthase; Ranibizumab; Receptors, Vascular Endothelial Growth Factor; Recombinant Fusion Proteins; Serpins; Superoxide Dismutase; Treatment Outcome; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor C

Topics: Aged; Aqueous Humor; Biomarkers; Diabetic Retinopathy; Erythropoietin; Eye Proteins; Female; Humans; Laser Therapy; Macular Edema; Male; Middle Aged; Nerve Growth Factors; Serpins

Over the past years, knowledge has expanded with regards to the multiple roles played by erythropoietin (EPO) in the body. Once believed to be a hormone synthesised in the kidney and involved only in the modulation of erythrocyte production, it is recognised now that EPO can be produced in many tissues, including the retina, and by many cells. In these tissues EPO is released in response to "tissue injury" and appears to have protective functions. Despite the extensive research conducted to date, the cues leading to release of EPO and its effects in the normal and diseased retina have not been fully elucidated. In vitro and in vivo experimental studies as well as small interventional clinical studies suggest a potential beneficial effect of externally administered EPO in early diabetic retinopathy and diabetic macular oedema. In contrast, controversy exists with regards to the possible use of EPO in proliferative diabetic retinopathy. Non-erythropoietic EPO-derived peptides, produced with the aim of increasing effectiveness and reducing side effects of EPO, are currently under investigation in early phase clinical trials.

Topics: Diabetic Retinopathy; Erythropoietin; Humans; Receptors, Erythropoietin; Retina

We investigated the association of signals from previous GWAS and candidate gene meta-analyses for diabetic retinopathy (DR) or nephropathy (DN), as well as an EPO variant in meta-analyses of severe (SDR) and mild diabetic retinopathy (MDR). Meta-analyses of SDR (≥severe non-proliferative diabetic retinopathy (NPDR) or history of panretinal photocoagulation) and MDR (≥mild NPDR), defined based on seven-field stereoscopic fundus photographs, were performed in two well-characterized type 1 diabetes (T1D) cohorts: the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC, n = 1,304) and Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR, n = 603). Among 34 previous signals for DR, after controlling for multiple testing, no association was replicated in our meta-analyses. rs1571942 and rs12219125 at PLXDC2 locus showed nominally significant (<0.05) association with SDR in the same direction as previous report, as did rs1801282 in PPARG gene with MDR. Among 55 loci previously associated with DN, three showed suggestive associations with SDR in our study without maintaining significance after correction for multiple testing. Of particular interest, rs1617640 (EPO) was not significantly associated with DR status, combined SDR-DN phenotype, time to SDR or time to DN (all P > 0.05). Lack of replication of previous DR hits and EPO despite reasonable statistical power implies that many of these may be false positives. Consistent with pleiotropy, we provide suggestive collective evidence for association between DR and variants previously associated with DN without reaching statistical significance at any single locus.

Topics: Clinical Trials as Topic; Diabetes Mellitus, Type 1; Diabetic Retinopathy; Erythropoietin; Female; Genetic Loci; Humans; Male; Polymorphism, Genetic; Receptors, Cell Surface

The earliest and most significant change in diabetic retinopathy (DR) is blood-retinal barrier (BRB) dysfunction, followed by two main pathologies that may cause severe visual impairment: Diabetic Macular Edema (DME) and Proliferative Diabetic Retinopathy (PDR). The pathological hallmarks of BRB dysfunction include loss of tight junction integrity, VEGF- and AGE-induced damage, oxidative stress, and inflammatory changes. Recently, several BRB protective factors have been reported. Our aim is to give a review of those protective factors and discuss new potential therapeutic targets for DR.

Topics: Animals; Blood-Retinal Barrier; Diabetic Retinopathy; Erythropoietin; Fenofibrate; Humans; Insulin-Like Growth Factor Binding Protein 3; Macular Edema; Protective Factors; Pyrazines; Sitagliptin Phosphate; Triazoles; Vascular Endothelial Growth Factor A

Erythropoietin (Epo) is the principal regulator of erythropoiesis by inhibiting apoptosis and by stimulating the proliferation and differentiation of erythroid precursor cells. However, Epo also performs extra-erythropoietic actions of which the neuroprotective effects are among the most relevant. Apart from kidney and liver, Epo is also produced by the brain and the retina. In addition, Epo receptor (Epo-R) expression has also been found in the brain and in the retina, thus suggesting an autocrine/paracrine action which seems essential for the physiological homeostasis of both brain and retina. In this review, we will give an overview of the current concepts of the physiology of Epo and will focus on its role in the retina in both normal conditions and in the setting of diabetic retinopathy. Finally, the reasons as to why Epo could be contemplated as a potential new treatment for the early stages of diabetic retinopathy will be given.

Topics: Animals; Diabetic Retinopathy; Erythropoietin; Eye Proteins; Humans; Microvessels; Nerve Tissue Proteins; Neuroprotective Agents; Receptors, Erythropoietin; Recombinant Proteins; Retina; Signal Transduction

Proliferative diabetic retinopathy (PDR), characterized by pathologic retinal angiogenesis, is a major cause of blindness in the USA and globally. Treatments targeting vascular endothelial growth factor (VEGF) have emerged as a beneficial part of the therapeutic armamentarium for this condition, highlighting the utility of identifying and targeting specific pathogenic molecules. There continues to be active research into the molecular players regulating retinal angiogenesis, including pro-angiogenic factors, anti-angiogenic factors, and integrins and matrix proteinases. New insights have been especially prominent regarding molecules which regulate specialized endothelial cells called tip cells, which play a lead role in endothelial sprouting. Together, these research efforts are uncovering new, important molecular regulators of retinal angiogenesis, which provide fertile areas for therapeutic exploration. This review discusses potential molecular targets, with an emphasis towards newer targets.

Topics: Angiogenesis Inhibitors; Blindness; Diabetic Retinopathy; Disease Progression; Erythropoietin; Female; Humans; Hyperglycemia; Macular Edema; Male; Retinal Neovascularization; Vascular Endothelial Growth Factor A

Topics: Angiopoietin-1; Animals; Cell Movement; Diabetic Retinopathy; Erythropoietin; Humans; Hyperglycemia; Inflammation; Mice; Mice, Transgenic; Neovascularization, Pathologic; Neovascularization, Physiologic; Receptor, TIE-2; Retina; Vascular Endothelial Growth Factor A

Topics: Animals; Diabetic Angiopathies; Diabetic Nephropathies; Diabetic Retinopathy; Erythropoietin; Humans; Hypoxia; Kidney Failure, Chronic; Models, Biological; Polymorphism, Single Nucleotide; Promoter Regions, Genetic

The hypothesis that soluble vasoproliferative growth factors cause new blood vessel growth (neovascularization) in proliferative diabetic retinopathy and other proliferative diseases of the retina was first proposed by Isaac Michaelson in 1948. Until recently, laser photocoagulation has been the preferred treatment for these diseases. VEGF, first identified in 1983 and associated with diabetic retinopathy in 1994, has been the focus of increasing research in this field. Several types of anti-VEGF molecules are being evaluated for efficacy; however, it is becoming evident that VEGF may not be the only, or even the major, molecule responsible for diabetic macular edema.

Topics: Angiogenesis Inhibitors; Angiogenic Proteins; Animals; Anti-Inflammatory Agents; Antioxidants; Diabetic Retinopathy; Erythropoietin; Eye Proteins; Fatty Acids, Omega-6; Hormone Antagonists; Humans; Immunosuppressive Agents; Insulin-Like Growth Factor I; Macular Edema; Nerve Growth Factors; Protein Kinase C; Protein Kinase Inhibitors; Receptors, Somatotropin; Serpins; Signal Transduction; Vascular Endothelial Growth Factor A

Diabetes continues to be a major source of -morbidity and mortality among working-age adults nationally and internationally. The microvascular complications of diabetes, including diabetic retinopathy, account for a major proportion of disease-associated morbidity and likely contribute to macrovascular complications. Although glycemic control contributes to -susceptibility for diabetic complications, some people with strict control develop these complications, whereas -others with poor control remain complication free. This suggests a genetic contribution to disease development. Although many genes and proteins of vascular growth have been studied in association with diabetic retinopathy, no definitive major predisposing genes or functional consequences of genetic variants have been identified for microvascular complications of the disease. In this article, we review the studies done on candidate genes.

Topics: Angiopoietin-1; Animals; Diabetic Retinopathy; Erythropoietin; Genetic Predisposition to Disease; Humans; Platelet-Derived Growth Factor; Vascular Endothelial Growth Factor A

Both chronic kidney disease (CKD) and type II diabetes mellitus (DM) are increasing in frequency among Western populations and both are potent risk factors for the development of anaemia. The presence of CKD and diabetes together represent the most important aetiopathogenic combination for the development of anaemia. New evidence has highlighted some of the underlying mechanisms which make diabetic patients more susceptible to dyserythropoiesis, particularly once they have developed concomitant CKD. In addition, recent publications from large-scale epidemiological studies have highlighted the impact of anaemia on diabetic patients. The purpose of this review was to focus on the pathophysiology and impact of anaemia in DM.

Topics: Anemia; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Nephropathies; Diabetic Neuropathies; Diabetic Retinopathy; Erythropoietin; Female; Humans; Kidney Failure, Chronic; Male; Quality of Life

Ocular vascular diseases such as diabetic retinopathy, retinal vein occlusion, and age-related macular degeneration, whose population increases along with aging, have become leading causes of severe visual disturbance. Macular edema and serous retinal detachment are associated with abnormal vascular leakage and tractional retinal detachment, and neovascular glaucoma is caused by retinal neovascularization. Such ocular vascular diseases are caused by vascular cell aging and vascular damage associated with lifestyle-related diseases including diabetes mellitus, hypertension, hyperlipidemia, and obesity. In the present study, we investigated molecular mechanisms in such vascular deficiencies using vascular cell biology methodology, and we propose novel strategies for the treatment of such vascular diseases. Along with aging, oxidative stress and physical stress, such as mechanical stretch, continuously and directly insult vascular cells. Such stress induces apoptosis by intracellular signaling through stress kinases in cultured retinal vascular cells. Inhibition of such stress kinases could be an effective treatment to protect the vascular cells against age-related damage. In a retinal vascular developmental model, pericyte loss causes pathology mimicking macular edema and proliferative diabetic retinopathy. Angiopoietin 1 (Ang 1) secreted by pericytes suppresses oxidative stress-induced intracellular signaling through stress kinases linked to cell apoptosis and normalizes such retinal pathology. This suggests that the paracrine action of Ang 1 in the pericytes is necessary to sustain normal retinal vasculature, and that Ang 1-triggered intracellular signaling is useful for the treatment of vascular cell pathology associated with pericyte loss. In diabetic retinopathy and retinal vein occlusion, retinal vessels regress along with retinal vascular cell apoptosis, and the retina becomes ischemic followed by pathological retinal neovascularization. VEGF has been recognized as a predominant factor to induce the ischemic retinal neovascularization. We found that retinal vascular cells have a characteristic pattern in VEGF receptor expression, which causes vascular pathology more frequently in the retina than in other organs. Neuropilin 1 (NRP 1), which enhances VEGF receptor function, is abundantly expressed in the retinal endothelial cells and is upregulated by VEGF itself and by hypoxia to regulate a positive feedback mechanism in retinal neovascularization. Th

Topics: Aging; Angiogenesis Inhibitors; Angiopoietin-1; Angiotensin II Type 1 Receptor Blockers; Animals; Apoptosis; Choroid Neoplasms; Diabetic Retinopathy; Drug Design; Erythropoietin; Humans; Life Style; Neuropilin-1; Oxidative Stress; Pericytes; Renin-Angiotensin System; Retinal Vein Occlusion; Signal Transduction; Vascular Endothelial Growth Factor A

Anaemia is a common finding in patients with diabetes, particularly in those with overt nephropathy or renal impairment. In tertiary clinics, at least one outpatient in five with diabetes has anaemia, for whom it constitutes a significant additional burden.. Anaemia is associated with an increased risk of diabetic complications including nephropathy, retinopathy and macrovascular disease. Anaemia may also be significant in determining the outcome of heart failure and hypoxia-induced organ damage in diabetes. While several factors contribute to the increased prevalence of anaemia in diabetes, the failure of the kidney to increase erythropoietin in response to falling haemoglobin appears to be the dominant factor. Although there is a clear rationale for correcting anaemia in people with diabetes, it remains to be established whether this will lead to improved outcomes. Moreover, the balance of risks, costs, and benefits remains to be established in patients with diabetes. The Trial to Reduce Cardiovascular Events with Aranesp (darbepoetin alpha) Therapy (TREAT) is a randomised controlled trial designed to determine the impact of anaemia correction on mortality and non-fatal cardiovascular events in patients with type 2 diabetes and stage 3-4 nephropathy.. It is anticipated that TREAT will help to define the optimal approach to the management of anaemia in diabetes.

Topics: Anemia; Diabetes Complications; Diabetic Angiopathies; Diabetic Nephropathies; Diabetic Retinopathy; Erythropoietin; Humans

Anemia has recently been recognized as a frequent complication of diabetic nephropathy, appearing earlier than in nondiabetic renal disease and amplifying the risks of cardiovascular and microvascular complications. A major cause is an inappropriate erythropoietin response to anemia, often accompanied by iron deficiency and therapy with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers.

Topics: Anemia; Diabetic Angiopathies; Diabetic Nephropathies; Diabetic Neuropathies; Diabetic Retinopathy; Disease Progression; Erythropoietin; Heart Diseases; Humans

Anaemia is a frequent complication of diabetic nephropathy. It has only recently been recognised that in diabetic patients anaemia is seen not only in preterminal renal failure, but also frequently in patients with only minor derangement of renal function. At any level of glomerular filtration rate (GFR) anaemia is more frequent and severe in diabetic compared to nondiabetic patients. A major cause of anaemia is an inappropriate response of erythropoietin to anaemia. Additional factors are iron deficiency and iatrogenic factors, e.g. ACE inhibitor treatment. When serum creatinine is still normal, the erythropoietin concentration is predictive of more rapid loss of glomerular function. When serum creatinine is elevated, the haemoglobin values are predictive of the rate of progression. It is currently under investigation whether reversal of anaemia attenuates the rate of progression. Because most of the late complications of diabetes (retinopathy, neuropathy, heart disease, peripheral arterial disease) involve ischaemic tissue damage, it would be intuitively plausible that treatment with human recombinant erythropoietin should be beneficial, but definite evidence for this hypothesis is currently not available.

Topics: Anemia; Diabetic Nephropathies; Diabetic Neuropathies; Diabetic Retinopathy; Erythrocytes, Abnormal; Erythropoietin; Heart Failure; Humans; Kidney Failure, Chronic; Myocardial Ischemia; Peripheral Vascular Diseases

Diabetes as the dominant cause of ESRD is also the major cause of renal anaemia. However, most patients with diabetic kidney disease will succumb to co-morbid vascular disease or heart failure before developing severe renal impairment. In these patients, anaemia is also common finding, with a 2-3 times greater prevalence and earlier onset than in patients with renal impairment from other causes. We have recently shown that at least one in five outpatients with type 1 or type 2 diabetes in tertiary referral clinics have anaemia, in whom it constitutes a significant additional burden. Impaired renal erythropoietin release in response to declining haemoglobin levels appears to be the major contributor to anaemia in diabetes. This may be due to the predominance of damage to cells and vascular architecture of the renal tubulointerstitium associated with diabetic nephropathy that may be apparent, like albuminuria, before demonstrable changes in renal function. In addition, systemic inflammation, autonomic neuropathy and reduce red cell survival may also compound anaemia in diabetes. While anaemia may be considered a marker of diabetic kidney disease, reduced haemoglobin levels, even within the normal range, identify diabetic patients with an increased risk of hospitalisation and mortality. Anaemia may also be significant in determining the outcome of heart failure and hypoxia-induced organ damage in patients with diabetes. Upcoming studies will determine whether correction of anaemia in diabetes will lead to improved outcomes in these patients.

Topics: Anemia; Blood Pressure; Diabetes Complications; Diabetic Angiopathies; Diabetic Neuropathies; Diabetic Retinopathy; Erythrocytes; Erythropoietin; Glomerular Filtration Rate; Hematopoiesis; Humans; Infections; Kidney; Microcirculation; Prevalence; Wound Healing

Topics: Anemia; Diabetic Nephropathies; Diabetic Retinopathy; Erythropoietin; Humans; Recombinant Proteins

To evaluate the effect of three intravitreal bevacizumab (IVB) injections alone or in combination with intravitreal erythropoietin (EPO) in the treatment of refractory diabetic macular edema (DME).. In a randomized double-blind clinical trial, 48 eyes of 34 diabetic patients with refractory DME were enrolled. Eyes were randomly assigned to receive either 3 monthly injections of 0.05 cc (1.25 mg) IVB plus 0.05 cc (1000 unit) EPO or 0.05 cc (1.25 mg) IVB alone. Main outcome was best-corrected visual acuity (BCVA) changes and secondary outcome was central macular thickness (CMT). The patients were followed for 6 months.. Mean BCVA changes up to 4 and 6 months were insignificant in both groups. It changed from 0.72 ± 0.56 logMAR at baseline to 0.74 ± 0.5 (P = 0.85) and 0.71 ± 0.44 (P = 0.40) in the combination group and from 0.48 ± 0.39 logMAR to 0.47 ± 0.35 (P = 0.48) and 0.52 ± 0.33 (P = 0.69) in the IVB alone group, at 4 and 6 months, respectively. The difference of mean BCVA changes between the groups was insignificant at both 4 and 6 months (P = 0.07 and P = 0.36, respectively). Within the group changes of mean CMT were significant only in the combination group at 4 and 6 months, from 518 ± 134 μ at baseline to 472 ± 151 to 475 ± 167 μ, respectively (P = 0.01 and P = 0.05). Corresponding changes were not significant in the IVB alone group. However, the difference between the groups was not significant at all visits (P = 0.51 and P = 0.71, respectively).. This clinical trial demonstrated that intravitreal erythropoietin had no additional effect to IVB in the treatment of refractory DME in the short term.. Clinical trials.gov identifier: NCT03821168.

Topics: Aged; Angiogenesis Inhibitors; Bevacizumab; Diabetic Retinopathy; Double-Blind Method; Drug Therapy, Combination; Erythropoietin; Female; Follow-Up Studies; Humans; Intravitreal Injections; Macula Lutea; Macular Edema; Male; Middle Aged; Tomography, Optical Coherence; Treatment Outcome; Vascular Endothelial Growth Factor A

Erythropoietin was administered to five anemic azotemic diabetic subjects for 1 year to assess the effect of increasing red cell mass on clinical well-being and the course of renal functional decline. None of the subjects manifested worsened hypertension or cerebrovascular or cardiovascular complications despite an increase in mean hematocrit from a baseline mean of 29.6% to a mean of 39.5%. The serum creatinine concentration after 1 year of treatment with erythropoietin was 3.7 mg/dL, which was unchanged from the baseline value of 3.5 mg/dL. Plasma viscosity remained constant as red cell mass increased. Although the viscosity of whole blood rose as the hematocrit increased, it was within the range of normal blood viscosity for an equivalent hematocrit. The favorable impact of erythropoietin treatment on three diabetic subjects who had macular edema and anemia is described. One hypothesis to explain the benefit of a raised hematocrit on both diabetic nephropathy and retinopathy is that the metabolic, hormonal, and hemodynamic components of the diabetic syndrome, in concert, produce tissue and cellular hypoxia that is ameliorated in part by the greater oxygen-transporting capacity of a raised red cell mass. The pseudohypoxia of diabetes may be implicated in the pathogenesis of diabetic neuropathy, retinopathy, muscular dysfunction, and nephropathy.

Topics: Blood Viscosity; Creatinine; Diabetic Nephropathies; Diabetic Retinopathy; Erythropoietin; Female; Hematocrit; Humans; Kidney Failure, Chronic; Macular Edema; Middle Aged; Recombinant Proteins

To determine the correlation of serum erythropoietin concentration with diabetic retinopathy in patients with type 2 diabetes mellitus.. Cross-sectional study. Place and Duration of the Study: Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from July to December 2021.. A total of 180 individuals were enrolled in the study and placed in 2 groups as group 1 have 90 cases of type 2 diabetes mellitus and group 2 having 90 age-matched healthy controls. Group 1 was further subclassified into proliferative diabetic retinopathy (PDR) and non-proliferative diabetic retinopathy (NPDR) subgroups by an expert ophthalmologist. Serum erythropoietin, creatinine, blood HbA1c, and haemoglobin were analysed. Correlation between stages of proliferation and serum erythropoietin, creatinine, blood HbA1c, and haemoglobin were analysed. An independent-sample student t-test was applied to compare mean Serum erythropoietin between PDR and NPDR groups. Pearson's correlation was applied among disease severity, and type of retinopathy. A p-value of ≤0.05 was considered significant.. The average age of participants in groups 1 and 2 was 45.88±8.6 and 56.6±10.23 years, respectively. More males (n=60, 66.7%) were noted in cases compared to controls (n=42, 46.7%). serum erythropoietin concentration observed in cases (8.4±1.87 IU/L) was higher than controls (6.50±0.9). The mean serum erythropoietin concentration in PDR (9.35±1.74 IU/L) was significantly greater than that in NPDR (7.3±1.38 IU/L, p <0.001). The serum concentration of erythropoietin in group 1 increased linearly with the severity of the disease (r=0.103).. Serum erythropoietin concentrations increased in uncontrolled type 2 diabetics more so in proliferative retinopathy cases, and increased with disease severity.. Erythropoietin, Diabetic retinopathy, Proliferative diabetic retinopathy.

Topics: Adult; Creatinine; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Erythropoietin; Glycated Hemoglobin; Humans; Male; Middle Aged

Topics: Asian People; Case-Control Studies; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Erythropoietin; Gene Frequency; Genetic Predisposition to Disease; Genotype; Humans; Polymorphism, Single Nucleotide; Transcription Factor 7-Like 2 Protein

Microglial activation in diabetic retinopathy and the protective effect of erythropoietin (EPO) have been extensively studied. However, the regulation of microglia in the retina and its relationship to inner blood-retinal barrier (iBRB) maintenance have not been fully characterised. In this study, we investigated the role of microglia in iBRB breakdown in diabetic retinopathy and the protective effects of EPO in this context.. In diabetic rat retinas, phagocytosis of endothelial cells by activated microglia was observed at 8 weeks, resulting in an increased number of acellular capillaries (increased by 426.5%) and albumin leakage. Under hypoxic conditions, activated microglia transmigrated to the opposite membrane of the transwell, where they disrupted the endothelial cell monolayer by engulfing endothelial cells. The activation and phagocytic activity of microglia was blocked by intravitreal injection of EPO. In vitro, IBA-1, CD11b and C1r protein levels were increased by 50.9%, 170.0% and 135.5%, respectively, by hypoxia, whereas the phosphorylated proteins of Src/Akt/cofilin signalling pathway components were decreased by 74.2%, 47.8% and 39.7%, respectively, compared with the control; EPO treatment abrogated these changes.. In experimental diabetic retinopathy, activated microglia penetrate the basement membrane of the iBRB and engulf endothelial cells, leading to iBRB breakdown. EPO exerts a protective effect that preserves iBRB integrity via activation of Src/Akt/cofilin signalling in microglia, as demonstrated in vitro. These data support a causal role for activated microglia in iBRB breakdown and highlight the therapeutic potential of EPO for the treatment of diabetic retinopathy. Graphical abstract.

Topics: Actin Depolymerizing Factors; Animals; Blood-Retinal Barrier; Cell Hypoxia; Coculture Techniques; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Endothelial Cells; Erythropoietin; Humans; Intravitreal Injections; Male; Microglia; Phagocytosis; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Signal Transduction; src-Family Kinases

The aim of this study was to investigate the relationship between erythropoietin rs1617640 polymorphism and proliferative diabetic retinopathy (PDR) in Slovenian subjects with type 2 diabetes mellitus. The second aim was to find whether erythropoietin expression in fibrovascular membranes varies among individuals carrying different genotypes of the rs1617640.. This was a retrospective cross-sectional study based on 797 unrelated Slovenian (Caucasian) participants with type 2 diabetes mellitus. The study group consisted of 217 cases with PDR and 580 controls without clinical signs of diabetic retinopathy. Each subject was genotyped for rs1617640 polymorphism. Fibrovascular membranes from 27 subjects who underwent vitreoretinal surgery were analysed with immunohistochemistry. We searched for expression of erythropoietin, its cognate receptor and for a pan-endothelial marker CD-34.. Our results show that subjects carrying a minor GG genotype had significantly higher risk for PDR in both unadjusted (p = 0.02) and adjusted (p = 0.04) recessive genetic models. Subjects with the GG genotype had a 1.6-fold increased risk of developing PDR compared to subjects carrying the major T allele. In fibrovascular membranes from subjects with PDR, the mean number of cells expressing EPO was significantly higher in G allele carriers compared to the homozygotes for the common T allele.. In Slovenian subjects with type 2 diabetes mellitus, a significant increased risk of PDR was found in GG carriers of the erythropoietin gene rs1617640 polymorphism.

Topics: Adult; Aged; Alleles; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Diabetic Retinopathy; DNA; Erythropoietin; Female; Follow-Up Studies; Gene Frequency; Genetic Predisposition to Disease; Genotype; Humans; Incidence; Male; Middle Aged; Polymorphism, Single Nucleotide; Retrospective Studies; Slovenia; Time Factors; Young Adult

Our aim in this study was to determine the association of erythropoietin (EPO) gene polymorphisms with diabetic retinopathy in patients with type 2 diabetes from northern India.. In this case-control study, we recruited 614 participants, consisting of 302 diabetic retinopathy cases and 312 individuals with confirmed type 2 diabetes without retinopathy as controls. EPO polymorphism analysis was performed in all participants using polymerase chain reaction and direct DNA sequence analysis.. The genotype distribution and allele frequency of the c.246+265G>A (rs507392) polymorphism differed significantly (p<0.05) between the retinopathy and control groups. For the -1306C>A (rs1617640) polymorphism, genotype distribution among the 2 groups analyzed differed significantly (p=0.047), but the distribution of allele frequency was not found to be statistically significant (p=0.07). For the c.∗772G>T (rs551238) variant, genotype distribution did not differ significantly when comparing the 2 groups (p=0.062), but allele frequency distribution did differ significantly (p=0.045). For the polymorphisms analyzed, namely rs507392 and rs1617640, a statistically significant association with retinopathy was observed (dominant model: adjusted odds ratio [OR], 2.23; 95% confidence interval [CI], 1.36 to 3.35; p<0.01; codominant model: adjusted OR, 1.45; 95% CI, 1.00 to 2.09; p=0.048). However, no significant association between c.∗772G>T (rs551238) polymorphism and diabetic retinopathy was found.. Our findings show 2 polymorphisms (c.246+265G>A [rs507392] and -1306C>A [rs1617640]) in EPO to be risk factors for type 2 diabetic retinopathy in a northern Indian cohort. To our knowledge, this is the first report from India to demonstrate an association between EPO gene polymorphisms and retinopathy.

Topics: Case-Control Studies; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Erythropoietin; Genotype; Humans; India; Polymorphism, Single Nucleotide

To explore the relationships between the aqueous and vitreous levels of vascular endothelial growth factor-A (VEGF-A), interleukin-8 (IL-8), placental growth factor (PlGF) and erythropoietin (EPO) in proliferative diabetic retinopathy (PDR) and neovascular glaucoma (NVG).. Aqueous and vitreous samples were obtained from patients with PDR and NVG during surgery. Aqueous and vitreous concentrations of VEGF-A, IL-8, PlGF and EPO were measured via enzyme-linked immunosorbent assay.. No correlation between the aqueous and vitreous levels of VEGF-A, IL-8, PlGF or EPO was found in both the PDR and the NVG eyes. Aqueous VEGF-A was significantly higher in the NVG group (317.55 ± 36.25 pg/ml, n = 15) than that in the PDR group (256.23 ± 46.11 pg/ml, n = 17, P < 0.001). The level of VEGF-A in aqueous (317.55 ± 36.25 pg/ml, n = 15) was significantly higher than that in vitreous (224.74 ± 60.32 pg/ml, n = 15, P < 0.001) in NVG patients. The level of IL-8 in aqueous (76.55 ± 10.88 pg/ml, n = 17) was significantly higher than that in vitreous (63.55 ± 10.74 pg/ml, n = 17, P = 0.001) in PDR patients. The level of EPO in aqueous (18.62 ± 2.87 mIU/ml, n = 15) was significantly higher than that in vitreous (15.97 ± 3.11 mIU/ml, n = 15, P = 0.022) in NVG patients. The ratio of aqueous versus vitreous for VEGF-A was significantly higher in the NVG group (1.475 ± 0.289, n = 15) than that in the PDR group (0.996 ± 0.227, n = 17, P < 0.001).. Aqueous levels of VEGF-A, IL-8, PlGF and EPO do not correlate with vitreous levels of those proteins. The relationship between protein levels in aqueous humor and vitreous might be dependent on different disease status or protein types investigated.

Topics: Adult; Aged; Aqueous Humor; Biomarkers; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Female; Glaucoma, Neovascular; Humans; Male; Middle Aged; Placenta Growth Factor; Vascular Endothelial Growth Factor A; Vitreous Body

The investigation of erythropoietin (EPO) has expanded to include potential nonhematopoietic roles in neural and retinal diseases, including diabetic retinopathy. However, it remains unclear how EPO functions to support the neural retina. Transgenic mice with hypoactive EPO receptor (EPOR) signaling (hWtEPOR) were compared with littermate control mice (WT) to test the role of EPOR signaling under normal conditions and after vascular injury and regrowth into the retina. Although retinal function tested with OptoMotry and electroretinography was comparable to adult (8-week-old) littermate WT mice, hWtEPOR mice had thinner inner and outer plexiform layers and a greater number of amacrine cells. Injury and repair caused by the oxygen-induced retinopathy model reduced visual acuity thresholds, reduced electroretinography amplitudes, and thinned the outer plexiform and inner nuclear layers of both WT and hWtEPOR 8-week-old mice. In hWtEPOR compared with WT mice, scotopic a-wave amplitudes were reduced by injury, despite no change in outer nuclear layer thickness; and peripheral rod, but not cone number, was reduced. Scotopic b-waves were reduced in injured hWtEPOR mice compared with WT, and rod bipolar cell ectopic neurites were increased in both genotypes after injury, suggesting a potential reparative process to preserve connectivity and the b-wave. Normal EPOR signaling appeared important because ectopic neurites and b-waves were lower in the hWtEPOR than WT injured mice.

Topics: Animals; Diabetic Retinopathy; Electroretinography; Erythropoietin; Female; Male; Mice; Mice, Transgenic; Receptors, Erythropoietin; Retina; Retinal Diseases; Signal Transduction; Vascular System Injuries

To explore the mechanisms of erythropoietin (EPO)'s protection on inner blood-retinal barrier (iBRB) in experimental diabetic retinopathy.. Male SD rats were rendered diabetic with streptozotocin, followed by intravitreal injection of EPO. The permeability of iBRB was examined with fluorescein isothiocyanate (FITC)-dextran. Human retinal microvascular endothelial cells (HRMECs) and human umbilical vein endothelial cells (HUVECs) were treated with glyoxal and studied for cell viability and barrier function. The expressions of vascular endothelial (VE)-cadherin, Src kinase, vascular endothelial growth factor (VEGF) and VEGF receptor-2 (VEGFR2) were analyzed with Western blot, ELISA, qPCR, or immunofluorescence.. VE-cadherin in rat retinas was down-regulated with diabetes progression. EPO treatment could increase VE-cadherin expression at week 8 and week 16. The expressions of p-Src and p-VE-cadherin were increased at week 2, while decreased at week 8 of diabetes; which were prevented by EPO. The leakage of FITC-dextran in 8-week diabetic rat retinas was ameliorated by EPO. In vitro results showed the expressions of VEGF, p-Src and p-VE-cadherin were increased significantly, accompanied with the decreased barrier function, which were prevented by EPO. Ranibizumab and CGP77675 also inhibited the glyoxal-induced phosphorylation of Src and VE-cadherin. Cellular fractionation showed EPO mitigated the VE-cadherin internalization in glyoxal-treated cells.. EPO maintained the expression of VE-cadherin in experimental diabetic retinopathy by inhibiting its phosphorylation and internalization through VEGF/VEGFR2/Src pathway, thus improved the integrity of iBRB.

Topics: Animals; Antigens, CD; Blood-Retinal Barrier; Cadherins; Capillary Permeability; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Down-Regulation; Endothelial Cells; Erythropoietin; Human Umbilical Vein Endothelial Cells; Humans; Male; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Retinal Vessels; src-Family Kinases; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2

To explore the mechanisms of erythropoietin (EPO) in maintaining outer blood-retinal barrier (BRB) in diabetic rats.. Sprague-Dawley rats were rendered diabetic with intraperitoneal injection of streptozotocin, and then followed by intravitreal injection of EPO. Two and four weeks later, the permeability of outer BRB was examined with FITC-dextran leakage assay, following a method to demarcate the inner and outer retina based on retinal blood supply. The glyoxal-treated ARPE-19 cells, incubated with EPO, soluble EPO receptor (sEPOR), Gö6976, or digoxin, were studied for cell viability and barrier function. The expressions of ZO-1, occludin, VEGFR2, HIF-1α, MAPKs, and AKT were examined with Western blot and immunofluorescence.. The major Leakage of FITC-dextran was detected in the outer nuclear layer in both 2- and 4-week diabetic rats. The leakage was largely ameliorated in EPO-treated diabetic rats. The protein expressions of ZO-1 and occludin in the RPE-Bruch's membrane choriocapillaris complex were significantly decreased, whereas HIF-1α and JNK pathways were activated, in 4-week diabetic rats. These changes were prevented by EPO treatment. The in vitro study with ARPE-19 cells confirmed these changes, and the protective effect of EPO was abolished by sEPOR. Gö6976 and digoxin rescued the tight junction and barrier function in glyoxal-treated ARPE-19 cells.. In early diabetic rats, the outer BRB might be more severely damaged and its breakdown is the major factor for retinal oedema. EPO maintains the outer BRB integrity through down-regulation of HIF-1α and JNK signallings, and thus up-regulating ZO-1 and occludin expressions in RPE cells.

Topics: Animals; Blood-Retinal Barrier; Blotting, Western; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Erythropoietin; Intravitreal Injections; Male; Occludin; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Retinal Vessels; Up-Regulation; Zonula Occludens-1 Protein

Erythropoietin (EPO) is one of the systemic angiogenic factors, and its role in ocular angiogenesis and in diabetic retinopathy (DR) is not yet fully understood. The latest research data reveal a possible correlation of higher erythropoietin concentrations in the blood and in the eye with the development of more advanced stages of DR. The main aim of this work was to examine the possible influence of serum concentrations of erythropoietin on the development of diabetic retinopathy in patients with diabetes mellitus type 2.. The research involved 90 patients examined at the University Eye Clinic of the Clinical Center of Vojvodina, Novi Sad, Serbia. The first group comprised 60 patients with diabetes mellitus lasting for 10 years or more, with diabetic retinopathy. The second, control group consisted of 30 healthy individuals. In the first group of 60 patients with diabetes, 30 of them had non-proliferative diabetic retinopathy (NPDR), and 30 had proliferative diabetic retinopathy (PDR). Laboratory EPO serum levels were determined, and they were correlated to the stage of DR. Concentration of EPO was assessed by ELISA method.. The highest average concentration of EPO in serum (9.95 mIU/ml) was determined in the group of people with diabetes with PDR. The lowest average concentration of EPO in the serum (6.90 mIU/ml) was found in the control group. The average concentration of EPO in serum in the group of patients with diabetes with NPDR was 7.00 mIU/ml. The EPO concentration in serum was elevated in the group of PDR, and it was directly proportional to the level of the clinical stadium of PDR, being significantly higher in the moderate and severe subgroup of PDR comparing to the control healthy subjects, NPDR and mild PDR (p = 0.007).. Significantly elevated serum concentration of EPO in the advanced stages of DR, and positive correlation between EPO serum concentration and clinical stages of PDR, suggest that erythropoietin represents an important growth factor from blood, which plays a significant role in retinal ischemia and angiogenesis in diabetic retinopathy, especially in the proliferative stage of this disease.

Topics: Aged; Aged, 80 and over; Case-Control Studies; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Erythropoietin; Female; Glycated Hemoglobin; Humans; Intraocular Pressure; Male; Middle Aged; Visual Acuity

To investigate the relationships of the severity of diabetic retinopathy with erythropoietin (EPO), Caspase-3 expression, and oxidative stress.. A total of 20 patients with non-proliferative diabetic retinopathy hospitalized from January 2017 to January 2018 were enrolled as observation group 1, 20 patients with proliferative diabetic retinopathy were chosen as observation group 2, and 20 patients with idiopathic macular hole were selected as control group. After admission, patients received all necessary examinations and underwent vitrectomy during which vitreous and retinal tissues were taken, and venous blood was collected. Then, the content of EPO, Caspase-3, nitric oxide (NO), and malondialdehyde (MDA) was detected through enzyme-linked immunosorbent assay (ELISA), the messenger ribonucleic acid (mRNA) levels of EPO, Caspase-3, NO, and MDA were measured via quantitative Polymerase Chain Reaction (qPCR), and the severity of diabetic retinopathy was evaluated by diabetic retinopathy grading score.. Observation group 1 and 2 had significantly decreased the content of EPO (p<0.05) and overtly increased Caspase-3, NO, and MDA content (p<0.05) in comparison with control group. Compared with those in observation group 1, the EPO content was clearly lowered in observation group 2 (p<0.05), and the content of Caspase-3, NO, and MDA was evidently elevated (p<0.05). The diabetic retinopathy grading score was remarkably lower in control group than that in both observation group 1 and observation group 2 (p p<0.05), and it was significantly enhanced in observation group 2 compared with that in observation group 1 (p<0.05). Correlation analysis showed that the EPO content was negatively correlated with the severity of diabetic retinopathy, while the content of Caspase-3, NO, and MDA was positively related to the severity of diabetic retinopathy.. The severity of diabetic retinopathy has a negative association with EPO and positive correlations with Caspase-3, NO, and MDA content.

Topics: Caspase 3; Diabetic Retinopathy; Erythropoietin; Female; Humans; Male; Middle Aged; Oxidative Stress; Severity of Illness Index

Ecto-5'-nucleotidase/CD73 and adenylate kinase-1 circulate in human vitreous fluid. Adenylate kinase activity is high in diabetic eyes with proliferative retinopathy. Diabetic eyes display higher intravitreal ATP/ADP ratio than non-diabetic controls. Soluble adenylate kinase maintains resynthesis of inflammatory ATP in diabetic eyes.

Topics: 5'-Nucleotidase; Adenosine; Adenosine Diphosphate; Adenosine Triphosphate; Adenylate Kinase; Adult; Aged; Chromatography, Thin Layer; Diabetic Retinopathy; Erythropoietin; Female; Humans; Male; Middle Aged; Nucleoside-Diphosphate Kinase; Retina; Statistics, Nonparametric; Vascular Endothelial Growth Factor A; Vitreous Body

The aim of this study was to investigate the association of three single nucleotide polymorphisms in the erythropoietin gene polymorphisms with diabetic retinopathy and additional role of gene-gene interaction on diabetic retinopathy risk. A total of 1193 patients (579 men, 614 women) with type 2 diabetes mellitus were selected, including 397 diabetic retinopathy patients and 796 controls (type 2 diabetes mellitus patients without diabetic retinopathy); the mean age of all participants was 56.7 ± 13.9 years. Three single nucleotide polymorphisms were selected: rs507392, rs1617640, and rs551238. The t-test was used for comparison of erythropoietin protein level erythropoietin levels in patients having different erythropoietin genotypes. Logistic regression model was used to examine the association between three single nucleotide polymorphisms and diabetic retinopathy. Odds ratio (OR) and 95% confident interval (95% CI) were calculated. Generalized multifactor dimensionality reduction was employed to analyze the impact of interaction among three single nucleotide polymorphisms on CVD risk. After covariates adjustment, the carriers of homozygous mutant of three single nucleotide polymorphisms have higher diabetic retinopathy risk than those with wild-type homozygotes, OR (95% CI) were 2.04 (1.12-2.35), 1.87 (1.10-2.41) and 1.15 (1.06-1.76), respectively. Generalized multifactor dimensionality reduction model indicated a significant three-locus model (p = 0.0010) involving rs507392, rs1617640, and rs551238. Overall, the three-locus models had a cross-validation consistency of 10 of 10, and had the testing accuracy of 60.72%. Subjects with TC or CC-TG or GG-AC or CC genotype have the highest diabetic retinopathy risk. In conclusion, our results support an important association of rs507392, rs1617640 and rs551238 minor allele of erythropoietin with increased diabetic retinopathy risk, and additional interaction among three single nucleotide polymorphisms.

Topics: Adult; Aged; Asian People; Case-Control Studies; China; Diabetic Retinopathy; Erythropoietin; Female; Genetic Predisposition to Disease; Humans; Logistic Models; Male; Middle Aged; Odds Ratio; Polymorphism, Single Nucleotide

This study was performed to investigate the correlation of erythropoietin gene polymorphisms with diabetic retinopathy (DR) in a Chinese cohort with type 2 diabetes mellitus (T2DM).. Case-control study held in Qilu hospital of Shandong University, China.. 792 T2DM individuals were involved, classified as groups DR (n = 448) and non-DR (NDR; n = 344). The DR group was subdivided into groups proliferative DR (PDR; n = 220) and non-PDR (NPDR; n = 228).. Three single-nucleotide polymorphisms, rs1617640, rs507392 and rs551238, in the erythropoietin gene were genotyped. Odds ratios (ORs) for the effects of erythropoietin gene polymorphisms on DR risk.. The genotype CC frequency in rs507392 was significantly lower in DR group (additive: OR, 0.45; 95% confidence interval [CI], 0.23-0.89; P = 0.027; recessive: OR, 0.44; 95%CI, 0.23-0.86; P = 0.012) or PDR group (additive OR, 0.18; 95%CI, 0.05-0.63; P = 0.002; recessive OR, 0.19; 95%CI, 0.06-0.66; P = 0.003) than in NDR group. The genotype CC frequency in rs551238 was significantly lower in DR group (additive OR, 0.42; 95%CI, 0.21-0.38; P = 0.016; recessive OR, 0.40; 95%CI, 0.20-0.79; P = 0.010) or PDR group (additive OR, 0.18; 95%CI, 0.05-0.62; P = 0.002; recessive OR, 0.18; 95%CI, 0.05-0.61; P = 0.002). No significant differences were detected in the distributions of rs1617640 genotype or all polymorphisms' alleles between groups NDR and DR, PDR or NPDR. Haplotype analyses did not provide any evidence for the correlation between the three polymorphisms and DR.. Our data suggest that rs507392 and rs551238 in the erythropoietin gene probably act to lessen the risk for DR and PDR in the Chinese T2DM cohort.

Topics: Aged; Asian People; Blood Glucose; Case-Control Studies; China; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Erythropoietin; Female; Gene Frequency; Genotype; Genotyping Techniques; Glycated Hemoglobin; Humans; Male; Middle Aged; Polymerase Chain Reaction; Polymorphism, Single Nucleotide

The neuroprotective effect of carbamylated erythropoietin (CEPO), an erythropoietin (EPO) derivative, in diabetic retinopathy (DR) has not been clearly verified. We conducted this study to investigate the potential neuroprotective role of CEPO in a streptozotocin-induced diabetic rat model.. Streptozotocin-induced diabetic rats and blank controls were treated with or without CEPO and EPO for 4 weeks. Retinal functional and histological changes were quantified by electroretinogram, light microscopy, and terminal dUTP nick end labeling assay. Gene and protein levels of colony-stimulating factor 2 receptor beta, low-affinity (CD131), EPO receptor (EPOR), THY1, glial fibrillary acidic protein (GFAP), and vascular endothelial growth factor (VEGF-A) in retinal tissues were determined by real-time PCR and western blotting, respectively. Vascular penetration was assessed by fluorescein retinal angiography.. Diabetic rats had decreased retinal thickness, decreased ganglion cells, and increased retinal neuron apoptosis. CEPO increased CD131 and THY1 expression, while EPO increased EPOR expression. High glucose increased GFAP expression in the diabetic group, but both CEPO and EPO attenuated the trend for increase. CEPO downregulated VEGF-A expression. The amplitudes of b-wave and oscillatory potentials were decreased in the untreated diabetic group, whereas neither parameter decreased in diabetic rats after CEPO or EPO treatment. Vascular leakage and microaneurysms in the diabetic group were significantly improved following CEPO treatment.. CEPO has similar anti-apoptotic effects to EPO in DR, but CEPO does not induce neovascularization. CEPO may exert neuroprotective effects via its receptor CD131.

Topics: Animals; Blotting, Western; Cytokine Receptor Common beta Subunit; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Electroretinography; Erythropoietin; Fluorescein Angiography; Glial Fibrillary Acidic Protein; In Situ Nick-End Labeling; Injections, Intraperitoneal; Male; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Receptors, Erythropoietin; Retina; Streptozocin; Vascular Endothelial Growth Factor A

Neurotrophic factor decreased in the early stage of diabetic retinal nerve cells. Neurons damage brain derived neurotrophic factor (BDNF) and receptor TrkB expression reduced. Erythropoietin (EPO) plays an important role in protecting early diabetic retinopathy. The rats were euthanized at 24 h after EPO vitreous injection and the retina was separated. HE staining was applied to observe the pathological tissue morphology. Immunohistochemistry, immunofluorescence, and Western blot were used to detect BDNF, TrkB, extracellular signal-regulated kinase (ERK), and glial fibrillary acidic portein (GFAP) expression. Retinal structure was clear in group C, while the retinal thickness and RGCs number decreased in group B at 24 w. Retinal thickness in group E was greater than in group B but lower than in group C. GFAP and ERK expression increased in both group B and E, whereas the latter was significantly lower than the former. TrkB protein level was in group E > B > C at 4 w, while it was in group C > group E > group B at 24 w. BDNF expression in group B was higher than in group C at 4 w, whereas it was opposite at 24 w. BDNF expression increased in group E at 4 w, and it was similar in group E compared with group C at 24 w. EPO vitreous injection can increase BDNF and TrkB expression, while reduce GFAP and ERK expression in diabetes rat retina. It could protect Müller cells through BDNF/TrkB pathway to play a role of nerve nutrition.

Topics: Animals; Brain-Derived Neurotrophic Factor; Cytoprotection; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Ependymoglial Cells; Erythropoietin; Extracellular Signal-Regulated MAP Kinases; Glial Fibrillary Acidic Protein; Glucose; Intravitreal Injections; Male; Rats, Wistar; Receptor, trkB; Retina; Signal Transduction; Time Factors

Zinc transporter 8 (ZnT8) was downregulated in hypoxic retina, which could be rescued by hypoxia-inducible factor-1α (HIF-1α) inhibition. Erythropoietin (EPO) protects retinal cells in diabetic rats through inhibiting HIF-1α as one of its mechanisms. We hence tried to explore the effect of EPO in regulating ZnT8 and protecting retinal cells in diabetic rats and possible mechanisms.. Diabetes was induced in Sprague-Dawley rats. Intravitreal injection of EPO was performed 1 month after diabetes onset. The CoCl2-treated rat Müller cell line (rMC-1) was cotreated with EPO, soluble EPO receptor (sEPOR), digoxin, or U0126. Cell viability, cell death, and intracellular zinc level were examined. The expression of ZnT8, HIF-1α, AKT, and ERK was studied.. In diabetic rat retinas, EPO significantly decreased HIF-1α expression and increased ZnT8 expression. In CoCl2-treated rMC-1 cells, EPO increased cell viability and decreased intracellular zinc. Erythropoietin or digoxin could activate ERK pathway, downregulate HIF-1α, and upregulate ZnT8. The effect of EPO was abolished by sEPOR and U0126. Transient knockdown of ZnT8 increased intracellular zinc level, but not to a degree that would decrease cell viability or cause cell death.. In diabetic retinas, EPO maintains zinc homeostasis through activating the ERK pathway and downregulating HIF-1α, and thus upregulating ZnT8 expression. This work proposed a possible new protective mechanism for EPO in, and indicated a potential target for, the treatment of diabetic retinopathy.

Topics: Animals; Blotting, Western; Cation Transport Proteins; Cells, Cultured; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Down-Regulation; Erythropoietin; Gene Expression Regulation; Hypoxia-Inducible Factor 1, alpha Subunit; Intravitreal Injections; Male; MAP Kinase Signaling System; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Retinal Ganglion Cells; RNA; Transcriptional Activation; Up-Regulation; Zinc Transporter 8

To investigate the intravitreal levels of potent vasoactive, angiogenic and extracellular matrix remodelling factors in the diabetic patients with simvastatin treatment.. This is an institutional, prospective, observational case-control study. Type-1 and type-2 diabetic patients on lipophilic simvastatin (N = 14) compared with patients without statin medication (N = 50). Vitreous samples were subjected to protein measurements of angiopoietin (Ang)-1 and Ang-2, erythropoietin (EPO), transforming growth factor (TGF)-β1, vascular endothelial growth factor (VEGF) by ELISA and matrix metalloproteinase (MMP)-2 and MMP-9 by gelatin zymography.. Intravitreal levels of Ang-2 (p = 0.029), VEGF (p = 0.001) and proMMP-9 (p = 0.015) were lower in simvastatin-treated than in non-statin-treated controls. In diabetics with macular oedema (DME), intravitreal Ang-2 (p = 0.006) and VEGF (p = 0.002) levels were lower in simvastatin-treated patients compared with non-statin-treated controls. In those patients with proliferative diabetic retinopathy (PDR), intravitreal Ang-2 (p = 0.002), TGF-β1 (p = 0.037), VEGF (p = 0.001) and pro- and totalMMP-9 (p = 0.004 and p = 0.007) levels were lower when receiving simvastatin medication.. In diabetic patients with DME or PDR, the intravitreal levels of permeability and proangiogenic factors Ang-2 and VEGF were lower in simvastatin-treated than in those without statin medication. Moreover, the levels of MMP-9 and TGF-β1, factors involved in the breakdown of basement membrane and fibroproliferation, were lower in patients with PDR having simvastatin medication. When acetylsalicylic acid was combined with simvastatin treatment, the intraocular levels of Ang-2 and VEGF were significantly lower than in diabetics treated with simvastatin alone. These data provide a novel insight into the potential protective mechanisms underlying simvastatin medication in patients with diabetic retinopathy complications.

Topics: Adult; Aged; Angiopoietin-2; Biomarkers; Case-Control Studies; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Female; Humans; Hypolipidemic Agents; Macular Edema; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Middle Aged; Prospective Studies; Simvastatin; Transforming Growth Factor beta1; Vascular Endothelial Growth Factor A; Vitrectomy; Vitreous Body

We studied and developed a gene-based intraocular erythropoietin (EPO) therapy for diabetic retinopathy (DR), by which the applicability of neuroprotective therapy with favorable safety profile is attempted.. Hematocrit (Hct) was measured in C57BL/6 mice after intramuscular injection of AAV2-CMV-hEPO virus. Diabetes was induced by intraperitoneal injection of streptozotocin in Sprague-Dawley (SD) rats. Subretinal or intravitreal injection was performed in SD rats and Dark Agouti (DA) rats. The human EPO (hEPO) concentration was measured with ELISA. Blood-retinal barrier (BRB) breakdown was measured with Evans blue permeation. Retinal function was evaluated with electroretinography (ERG). Retinal cell apoptosis was detected with TUNEL. Retinal thickness and cell counts were examined by light microscopy. Retinal vascular changes were evaluated with fundus fluorescein angiography (FFA) and confocal microscopy.. The serum hEPO was elevated 2 weeks after AAV2-CMV-hEPO virus injection, and Hct began to increase after 4 weeks. After subretinal injection, hEPO expressions in aqueous humor, vitreous, and retina followed a dose- and time-dependent manner. In the AAV2-CMV-hEPO-treated diabetic group, BRB was maintained, and retinal cell apoptosis was significantly reduced. The ERG results showed that the retinal function remained unchanged for at least one year after subretinal injection of AAV2-CMV-hEPO virus. Long-term expression of hEPO following subretinal injection of AAV2-CMV-hEPO virus did not induce neovascularization in retina and choroid.. The AAV2-CMV-hEPO gene therapy is safe, and it exerts long-term protective effects on diabetic retinas. Thus, the gene therapy by using AAV2-CMV-hEPO for DR is feasible.

Topics: Animals; Apoptosis; Blood-Retinal Barrier; Cells, Cultured; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Dose-Response Relationship, Drug; Electroretinography; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Follow-Up Studies; Genetic Therapy; Humans; Intravitreal Injections; Male; Mice; Mice, Inbred C57BL; Rats; Rats, Sprague-Dawley; Retina; Time Factors; Treatment Outcome

This study compared systemic and intraocular concentrations of erythropoietin (EPO) and vascular endothelial growth factor (VEGF) in patients with type 2 diabetes (T2D) and proliferative diabetic retinopathy (PDR) with levels in patients without diabetes, and looked for possible correlations between the concentrations found and other variables analyzed.. Concentrations of EPO and VEGF were measured in the aqueous and vitreous humours and serum of patients undergoing vitrectomy for PDR (33 patients) or for macular holes or puckers (20 control patients). EPO was assayed by radioimmunoassay, with a lower limit of detection (LOD) of 1.0 mIU/mL. VEGF was assayed using enzyme-linked immunosorbent assay (ELISA), with a lower LOD of 10.0 pg/mL.. EPO concentrations in serum did not differ significantly between the two groups, whereas EPO in vitreous and aqueous were higher in diabetic than in non-diabetic patients. VEGF in serum was lower in diabetic patients than in non-diabetics; conversely, VEGF concentrations in vitreous were significantly higher in diabetic patients. A direct correlation was found between vitreous and aqueous EPO concentrations, and between vitreous EPO and blood glucose concentrations. A significant, negative correlation between vitreous EPO concentration and age was also recorded.. High EPO concentrations in the vitreous of patients with PDR and its correlation with blood glucose suggest that EPO could play a role in the pathogenesis of PDR. All possible factors affecting serum and ocular concentrations of EPO and VEGF should be determined to identify compounds able to prevent and control this serious microvascular complication of diabetes.

Topics: Aged; Aqueous Humor; Cohort Studies; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Erythropoietin; Female; Humans; Linear Models; Male; Middle Aged; Vascular Endothelial Growth Factor A; Vitreous Body

Royal College of Surgeons (RCS) rats develop vasculopathy as photoreceptors degenerate. The aim of this study was to examine the effect of erythropoietin (EPO) on retinopathy in RCS rats.. Fluorescein angiography was used to monitor retinal vascular changes over time. Changes in retinal glia and vasculature were studied by immunostaining. To study the effects of EPO on retinal pathology, EPO (5000 IU/kg) was injected intraperitoneally in 14 week old normal and RCS rats twice a week for 4 weeks. Changes in the retinal vasculature, glia and microglia, photoreceptor apoptosis, differential expression of p75 neurotrophin receptor (p75NTR), pro-neurotrophin 3 (pro-NT3), tumour necrosis factor-α (TNFα), pigment epithelium derived factor (PEDF) and vascular endothelial growth factor-A (VEGF-A), the production of CD34(+) cells and mobilization of CD34(+)/VEGF-R2(+) cells as well as recruitment of CD34(+) cells into the retina were examined after EPO treatment.. RCS rats developed progressive capillary dropout and subretinal neovascularization which were accompanied by retinal gliosis. Systemic administration of EPO stabilized the retinal vasculature and inhibited the development of focal vascular lesions. Further studies showed that EPO modulated retinal gliosis, attenuated photoreceptor apoptosis and p75NTR and pro-NT3 upregulation, promoted the infiltration of ramified microglia and stimulated VEGF-A expression but had little effect on TNFα and PEDF expression. EPO stimulated the production of red and white blood cells and CD34(+) cells along with effective mobilization of CD34(+)/VEGF-R2(+) cells. Immunofluorescence study demonstrated that EPO enhanced the recruitment of CD34+ cells into the retina.. Our results suggest that EPO has therapeutic potentials in treatment of neuronal and vascular pathology in retinal disease. The protective effects of EPO on photoreceptors and the retinal vasculature may involve multiple mechanisms including regulation of retinal glia and microglia, inhibition of p75NTR-pro-NT3 signaling together with stimulation of production and mobilization of bone marrow derived cells.

Topics: Animals; Apoptosis; Blotting, Western; Diabetic Retinopathy; Erythropoietin; Flow Cytometry; Fluorescein Angiography; Fluorescent Antibody Technique; Image Processing, Computer-Assisted; In Situ Nick-End Labeling; Neuroglia; Rats; Rats, Mutant Strains; Receptor, Nerve Growth Factor; Retina; Retinal Vessels; Tumor Necrosis Factor-alpha

The purpose of this study was to evaluate whether any stage of diabetic retinopathy (DR) is associated with levels of plasma erythropoietin and other plasma parameters.. It was examined a representative sample of 180 type 2 diabetes patients aged 40 to 79 years. Ophthalmic examination including a funduscopic examination, performed by an experienced ophthalmologist and the retinal finding were classified according to the grading system for diabetic retinopathy of ETDRS (Early Treatment Diabetic Retinopathy Study). It was measured the levels of plasma erythropoietin, cholesterol, triglyceride, apolipoproteins A and B, C-reactive protein, fasting blood glucose and hemoglobin A1C (HbA1C) in 88 DR patients and 92 controls without DR. Risk factors correlated with DR were compared between groups.. The study group of 180 patients included 72 males and 108 females. The mean age of the patients with and without DR was 57.36 ± 8.87 years and 55.33 ± 8.28 years, respectively. Of the 88 patients with DR, only 9 (10%) had proliferative DR and the rest suffered from non-proliferative DR. The mean plasma levels of erythropoietin in proliferative DR group showed a significant difference in comparison to other groups. The mean plasma levels of cholesterol, triglyceride, apolipoproteins A and B, C-reactive protein, and fasting blood glucose were not significantly different in the three groups except for HbA1C. The absolute relative risk (ARR) also showed that erythropoietin was an increasing risk for proliferative DR (ARR, 1.17; 95% confidence interval, 1.060 to 1.420; odds ratio,1.060).. Of the factors studied, erythropoietin level showed significant increase in proliferative DR group. The stepwise raised in mean plasma erythropoietin level which demonstrates significant correlation with proliferative DR versus remaining two groups, will be an indication of its role in proliferative DR.

Topics: Adult; Aged; Blood Glucose; Cholesterol; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Female; Fluorescein Angiography; Glycated Hemoglobin; Humans; Male; Middle Aged; Risk Factors

Retinal neuronal cell dysfunction and even cell death are associated with increased excitotoxic glutamate (Glu) level in the retina. Our aim was to study a causative mechanism of Glu on retinal cell death and explore the neuroprotective role of erythropoietin (EPO) against Glu neurotoxicity in the diabetic retina.. Male Sprague-Dawley (SD) rats and R28 cell line were employed in this study. Diabetes was induced with intraperitoneal injection of streptozotocin (STZ) in SD rats. Two weeks after diabetes onset, the intravitreal injection was performed; 4 days later, the retinas were harvested for testing. R28 cells were treated with Glu, Glu+EPO, or Glu+EPO+soluble EPO receptor (sEPOR), respectively, for 24 hours, and then the cells were collected for the following studies. Glutamate level in the retina was measured with a glutamate assay kit. Cell death was determined with TUNEL staining. The changes in glutamine synthetase (GS), glutamate-aspartate transporter (GLAST), ionotropic glutamate receptors (iGluRs), apoptosis-inducing factor (AIF), and poly(ADP-ribose) (PAR) polymer were studied with RT-PCR, Western blot, and immunofluorescence.. In 2-week diabetic rat retinas, Glu concentration was approximately 1.21-fold that in normal control. TUNEL staining demonstrated that retinal cell death was increased. Retinal GS and GLAST expressions were decreased, while the iGluRs, for example, KA1 and NR1, and PAR polymer expression was increased. In R28 cells, 24 hours after Glu (10 mM) treatment, the cell viability was decreased by 52.7%; KA1, NR1, PAR polymer, and nuclear AIF all increased in expression. The above conditions could be largely reversed by EPO both in vivo and in vitro. The protective effect of EPO was abolished by sEPOR.. Erythropoietin showed a neuroprotective function against Glu-mediated neurotoxicity both in diabetic rat retina and in Glu-treated R28 cells. The neuroprotective mechanisms were largely through maintaining the normal expression of glutamate-glutamine cycle-related proteins and inhibiting AIF translocation and PAR polymer formation.

Topics: Amino Acid Transport System X-AG; Animals; Apoptosis Inducing Factor; Cell Death; Cell Line; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Disease Models, Animal; Erythropoietin; Excitatory Amino Acid Antagonists; Glutamate-Ammonia Ligase; Glutamic Acid; Intravitreal Injections; Male; Poly Adenosine Diphosphate Ribose; Rats; Rats, Sprague-Dawley; Receptors, Erythropoietin; Receptors, Glutamate; Retina

The aim of this study was to evaluate concentrations of erythropoietin (EPO) and vascular endothelial growth factor (VEGF) in serum, aqueous and vitreous humour of diabetic patients with proliferative retinopathy (PDR) and to verify their possible modifications induced by intravitreal injection of bevacizumab (IVB).. This prospective observational study was performed on patients who underwent vitrectomy for proliferative diabetic retinopathy and macular hole or pucker. The study sample consisted of 33 patients with proliferative diabetic retinopathy and 20 non-diabetic patients with macular hole or pucker. EPO and VEGF levels in serum, aqueous and vitreous humour were measured in both groups. In diabetic patients measures were performed before and after IVB.. EPO and VEGF levels in aqueous and vitreous humour were markedly increased in diabetic patients with PDR as compared with those recorded in the control group (P<0.001); contrarily, EPO serum levels were similar in both groups (p=not significant). IVB did not affect EPO levels (aqueous 39.1 ± 29.2 vs. 38.6 ± 26.1; vitreous 179.3 ± 88.3 vs. 131.6 ± 67.8; serum 9.2 ± 5.8 vs. 6.9 ± 3.7 mUI/mL); conversely, VEGF concentration significantly decreased 15 days after IVB in serum and ocular fluids (aqueous 141.6 ± 12.3 vs. 81.4 ± 5.4; vitreous 180.4 ± 45.8 vs. 95.8 ± 23.6; serum 113.9 ± 52.8 vs. 73.2 ± 65.6 mUI/mL).. These findings demonstrate that the production of VEGF and EPO is regulated by different mechanisms. Intraocular levels of EPO in diabetic patients were significantly higher than those recorded in serum, suggesting a local production. In addition, bevacizumab does not influence intraocular levels of EPO.

Topics: Aged; Antibodies, Monoclonal, Humanized; Aqueous Humor; Bevacizumab; Body Fluid Compartments; Comorbidity; Diabetic Retinopathy; Erythropoietin; Female; Humans; Intravitreal Injections; Macular Edema; Male; Middle Aged; Prospective Studies; Retinal Perforations; Serum; Vascular Endothelial Growth Factor A; Vitrectomy; Vitreoretinopathy, Proliferative; Vitreous Body; Vitreous Hemorrhage

Angiogenesis in diabetic retinopathy (DR) is a multifactorial process regulated by hypoxia-induced growth factors and inflammatory cytokines. In addition to the angiogenic switch, the proteolytic processing and altered synthesis of the extracellular matrix are critical steps in this disease. This study was performed to evaluate the levels of matrix metalloproteinase-2 and matrix metalloproteinase-9 (MMP-2 and MMP-9), angiopoietin-1 and angiopoietin-2 (Ang-1 and Ang-2), vascular endothelial growth factor (VEGF), erythropoietin (EPO) and transforming growth factor-β1 (totalTGFβ1) in the vitreous of diabetic eyes undergoing vitrectomy compared with control eyes operated because of macular hole or pucker.. Prospective consecutive controlled observational study performed in the unit of vitreoretinal surgery in Finland during the years 2006-2008. Vitreous samples were collected before the start of the conventional 3-ppp vitrectomy. Vitreous MMP-2 and MMP-9, Ang-1 and Ang-2, VEGF, EPO and TGFβ1 concentrations were measured from 69 patients with Type 1 or 2 diabetes and 40 controls.. Comparison of eyes with DR with controls revealed that the mean vitreous concentrations of proMMP-2 (p = 0.0015), totalMMP-2 (p = 0.0011), proMMP-9 (p = 0.00001), totalMMP-9 (p < 0.00001), Ang-2 (p < 0.00001), VEGF (p < 0.00001), EPO (p < 0.00001) and totalTGFβ1 (p = 0.000026) were significantly higher in the former group. A multivariate logistic regression analysis suggested intravitreal Ang-2 concentration being the key marker of PDR (p = 0.00025) (OR = 1507.9).. The main new finding is that the intravitreal concentrations of Ang-2 correlated significantly with MMP-9, VEGF, EPO and TGFβ1 levels in diabetic eyes undergoing vitrectomy. Thus, these factors could promote retinal angiogenesis synergistically.

Topics: Aged; Angiopoietin-1; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Female; Humans; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Middle Aged; Prospective Studies; Retinal Neovascularization; Retinal Perforations; Tomography, Optical Coherence; Transforming Growth Factor beta1; Up-Regulation; Vascular Endothelial Growth Factor A; Vesicular Transport Proteins; Vitrectomy; Vitreous Body

A single intravitreal injection of erythropoietin (EPO) (50 ng/eye) or phosphate-buffered saline was administered to 5-week-old Sprague-Dawley rats at the onset of diabetes mellitus (DM) to determine and evaluate the protective effect of EPO on retinal microvessels. DM was induced by an intraperitoneal injection of streptozotocin (STZ; 60 mg/kg body weight). Morphological changes in microvessels in flat retinal preparations were evaluated during the subsequent 4 weeks by three-dimensional imaging of all blood vessels stained with fluorescein isothiocyanate-conjugated tomato lectin, following immunofluorescence techniques. No marked differences were observed in the shape or density of retinal vessels and the number of retinal capillary branches of the four groups [control, EPO, DM, and DM/EPO] up to 4 weeks after STZ administration. We also observed unique type IV collagen-positive filamentous structures that lacked both cellular elements and blood circulation (lectin-/type IV+ acellular strands), suggesting regressed vessel remnants. The lectin-/type IV+ acellular strands were detected soon after the onset of DM in the diabetic rats, and the number of these structures increased in the DM group (P < 0.01). A single intravitreal injection of EPO caused a significant reduction in the number of lectin-/type IV+ acellular strands to levels observed in the control group. However, the lectin-/type IV+ acellular strands were observed in the central area of the retina near the optic disc in all four groups. Intravitreal injection of EPO resulted in downregulation of the EPO receptor, vascular endothelial growth factor (VEGF), and VEGF receptor at 4 weeks. We conclude that EPO may play a primary role against the progression of diabetic retinopathy by reducing blood vessel degeneration at a very early disease stage.

Topics: Animals; Blood Glucose; Cell Proliferation; Collagen Type IV; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Endothelium, Vascular; Erythropoietin; Fluorescent Antibody Technique, Indirect; Fluorescent Dyes; Imaging, Three-Dimensional; Intravitreal Injections; Male; Plant Lectins; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Receptors, Erythropoietin; Receptors, Vascular Endothelial Growth Factor; Retinal Vessels; RNA, Messenger; Vascular Endothelial Growth Factor A

To examine vitreous succinate levels from proliferative diabetic retinopathy (PDR) patients and ascertain their association with PDR activity.. Comparative case series.. A total of 81 eyes of 72 PDR patients were divided into active PDR (22 eyes), quiescent PDR (21 eyes), and active PDR with intravitreal bevacizumab injection (38 eyes). Twenty epiretinal membrane (ERM) patients (21 eyes) served as controls.. Mean vitreous succinate levels were 1.27 μM in ERM and 2.20 μM in PDR, with the differences statistically significant (P = .03). When comparing mean vitreous succinate levels (active PDR: 3.32 μM; quiescent PDR: 1.02 μM; active PDR with intravitreal bevacizumab injection: 1.20 μM), significant differences were found between active and quiescent PDR (P < .01) and between active PDR and active PDR with intravitreal bevacizumab injection (P < .01). Even though succinate levels were low, retinopathy activities were very high in patients with active PDR with intravitreal bevacizumab injection. Mean vitreous vascular endothelial growth factor (VEGF) levels (active PDR: 1696 pg/mL; quiescent PDR: 110 pg/mL; active PDR with intravitreal bevacizumab injection: n.d.) were similar to previous reports. Mean vitreous erythropoietin levels (active PDR: 703 mIU/mL; quiescent PDR: 305 mIU/mL; active PDR with intravitreal bevacizumab injection: 1562 mIU/mL) suggested very high retinopathy activities in patients with active PDR with intravitreal bevacizumab injection.. Succinate, like VEGF, may be an angiogenic factor that is induced by ischemia in PDR. Although succinate is reported to promote VEGF expression, VEGF inhibition decreases succinate. Thus, VEGF, via a positive feedback mechanism, may regulate succinate.

Topics: Aged; Angiogenesis Inhibitors; Antibodies, Monoclonal, Humanized; Aqueous Humor; Bevacizumab; Chromatography, High Pressure Liquid; Diabetic Retinopathy; Epiretinal Membrane; Erythropoietin; Female; Humans; Intravitreal Injections; Male; Mass Spectrometry; Middle Aged; Retinal Neovascularization; Succinic Acid; Vascular Endothelial Growth Factor A; Vitreous Body

Topics: Anemia; Angiogenesis Inhibitors; Biomarkers; Diabetic Retinopathy; Erythropoietin; Humans; Ischemia; Models, Biological

We determined whether the concentrations of VEGF, erythropoietin, and endostatin in the vitreous are altered after vitrectomy in patient with proliferative diabetic retinopathy (PDR).. We measured the levels of VEGF, erythropoietin, and endostatin by sandwich ELISA in vitreous samples collected from 38 eyes of 33 patients with PDR before pars plana vitrectomy (without IOL implantation) and the same 38 eyes during IOL implantation 3.1 to 25.7 (mean 6.7) months after the initial vitrectomy.. The mean vitreous levels of VEGF (964.5 pg/mL) and erythropoietin (1359.5 pg/mL) in the samples collected before vitrectomy were significantly higher in patients with PDR than in the control patients (0.68 and 70.7 pg/mL, respectively; P < 0.01). The levels of VEGF (292.5 pg/mL) and erythropoietin (557.9 pg/mL) in the samples from eyes with PDR collected at the time of IOL implantation were significantly lower than those collected before vitrectomy (P < 0.01). In contrast, the changes in the level of endostatin were not significant after vitrectomy. The VEGF and erythropoietin levels in the vitreous fluid from patients with PDR were correlated inversely with the interval between the initial vitrectomy and the time of the IOL implantation.. The significant decrease in the intravitreal concentration of VEGF and erythropoietin, and an absence of a significant change in the endostatin indicated a shift in the antiangiogenic balance in the vitreous of patients with PDR after successful vitrectomy.

Topics: Adult; Aged; Diabetic Retinopathy; Endostatins; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Female; Humans; Laser Coagulation; Lens Implantation, Intraocular; Male; Middle Aged; Retinal Neovascularization; Vascular Endothelial Growth Factor A; Vitrectomy; Vitreous Body

Angiogenic factors such as vascular endothelial growth factor (VEGF), erythropoietin, and angiopoietin play important roles in the pathophysiology of diabetic retinopathy. Increased amounts of reactive oxygen species (ROS) are also known to associated with diabetic retinopathy and VEGF expression. This study evaluated the effect of a simvastatin on ROS generation and the changes in various angiogenic factors in the retinas of diabetic rats.. The rats were divided into normal, diabetes mellitus (DM), and simvastatin-treated groups (each group, n = 10). Diabetes was induced by intraperitoneal injection of streptozotocin into 20 Sprague-Dawley rats. After diabetic induction, simvastatin (5mg/kg) was administered orally to ten rats. The expression levels of VEGF, erythropoietin, angiopoietin 1 and 2, and NADPH oxidase were examined in rat retinas by RT-PCR and Western blot. Superoxide formation was examined by dihydroethidium (DHE) staining.. DHE analysis revealed increased superoxide formation in the retinas of the diabetic group, which was decreased in the group treated with simvastatin. Western blot analysis showed that NADPH oxidase levels were decreased in the diabetic group and remained normal in the simvastatin-treated group. Simvastatin treatment blocked hyperglycemia-induced increases in VEGF, angiopoietin 2 and erythropoietin levels, as demonstrated by RT-PCR and Western blot analysis.. Simvastatin treatment led to suppression of superoxide formation and decreased expression of VEGF, angiopoietin 2 and erythropoietin in diabetic rat retinas.

Topics: Administration, Oral; Angiogenic Proteins; Angiopoietin-1; Animals; Blotting, Western; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Electrophoresis, Polyacrylamide Gel; Erythropoietin; Fluorescent Antibody Technique, Indirect; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Male; NADPH Oxidases; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Simvastatin; STAT3 Transcription Factor; Vascular Endothelial Growth Factor A

To profile the pattern of gene expression in diabetic rat retinas with or without intravitreal injection of erythropoietin.. By using streptozotocin-induced diabetic rats, after intravitreal injection of erythropoietin, neurosensory retinas were collected to determine the effect of erythropoietin on gene expression.. Three groups of Sprague-Dawley rats were studied: normal control (15), diabetic rats with saline injection (15) and diabetic rats with intravitreal erythropoietin treatment (15).. Diabetes was induced by intra-peritoneal injection of streptozotocin. Intravitreal injection of erythropoietin was performed at the following time points: 0, 30 and 120 days after diabetes onset. Four days after each injection at above-mentioned time points, the retinas were harvested for microarray assay. The real-time PCR was used to evaluate the microarray data.. Genes encoding inflammatory factors, such as interleukin-2 and interleukin-11, which were upregulated in the diabetic retinas, were restored after erythropoietin treatment. Genes encoding pro-apoptotic effectors, like Tnfrsf5, Bid3 and Bcl2l1, were also upregulated in diabetic rats and attenuated in erythropoietin-treated group. In addition, real-time PCR were employed to confirm the changes of the genes Trex2, G1P2, DHX58, RGD1311906 and LOC689064, which have not been reported in diabetic retinopathy.. Intravitreal erythropoietin treatment is able to normalize the gene expression responsible for pro-apoptotic and inflammatory responses noted in diabetic retinas.

Topics: Animals; Diabetes Mellitus, Experimental; Diabetic Retinopathy; DNA Primers; Erythropoietin; Eye Proteins; Gene Expression Profiling; Gene Expression Regulation; Intravitreal Injections; Male; Protein Array Analysis; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

Diabetic retinopathy (DR) is a leading cause of acquired blindness among the people at working age. Although remarkable advances have been made in the treatment of the proliferative form of DR, there is still no effective treatment for the most prevalent early form of DR. The exact etiology and molecular pathogenesis of the early DR are not fully understood, but the selective loss of pericytes is believed to play a major role in the pathological process of DR. Herein we propose a novel approach to the treatment of early form of DR, using erythropoietin (EPO). We hypothesize that EPO reduces the loss of retinal pericytes, and therefore can be used as a novel therapeutic agent for early form of DR, which is based on its antioxidant, anti-inflammatory, and neuroprotective properties. If successful, future studies based on this hypothesis may also help shield the lights on the molecular mechanisms of early DR.

Topics: Animals; Apoptosis; Diabetic Retinopathy; Erythropoietin; Female; Humans; Hypoxia; Male; Mice; Models, Theoretical; Neurons; Pericytes; Retina; Treatment Outcome

Diabetic retinopathy (DR) is a chronic, low-grade inflammatory disease. We aimed to investigate the regulatory effects of erythropoietin (EPO) on the inflammatory cytokine production by Muller cells under the condition of DR. The expression levels of TNF-alpha, IL-1beta, IL-6 and VEGF in cultured rat Muller cells were enhanced by 1 mM glyoxal. The elevated TNF-alpha and IL-1beta, but not IL-6 and VEGF, were decreased by 2 U/ml EPO as detected by real-time PCR and ELISA. Moreover, the activity of AP-1 but not NF-kappaB was modulated by glyoxal and EPO. Intravitreal injection of EPO performed 24 h prior to sacrifice significantly reduced TNF-alpha and IL-1beta production while moderately attenuating IL-6 and VEGF in the retinas of streptozotocin-induced diabetic rats. Furthermore, Muller cells were identified as the main source of IL-1beta production as indicated by co-localization of IL-1beta and CRALBP in situ. These findings implicate therapeutic potential of EPO in the amelioration of inflammation in diabetic retinas.

Topics: Animals; Cell Line; Cytokines; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Gene Expression Regulation; In Situ Nick-End Labeling; Interleukin-1beta; Interleukin-6; Luciferases; NF-kappa B; Rats; Reverse Transcriptase Polymerase Chain Reaction; Tetrazolium Salts; Thiazoles; Transcription Factor AP-1; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factor A

The outer blood-retinal barrier is formed by retinal pigment epithelial (RPE) cells and its disruption significantly contributes to the development of diabetic macular edema (DME). The aim of the study was to explore whether erythropoietin (Epo) has beneficial effects on the barrier function of human RPE cells and the main downstream pathways involved. ARPE-19 cells were cultured in standard conditions and under conditions leading to the disruption of the monolayer [25 mmol/L D-glucose plus IL-1β (10 ng/mL)]. Epo (200 mU/mL/day) was added during the last 2 days of the experiment. The experiments were repeated in the presence of an Epo neutralizing antibody and specific inhibitors of JAK2 and PI3K (AG490 and LY294002, respectively). Permeability was evaluated by fluorescein isothiocyanate dextran (70 kDa) movements. Distribution of tight junction proteins was examined by immunofluorescence. Changes in cytosolic Ca(2+) induced by Epo were also measured. Epo treatment was able to prevent but not to restore the increase of permeability induced by high glucose plus IL-1β. The protective effect of Epo on RPE barrier function was completely blocked by AG490 and almost completely abolished by LY294002. In addition, Epo was able to increase cytosolic Ca(2+) with dependence on extracellular calcium influx and this effect was blocked by either JAK2 or PI3K inhibition. We conclude that RPE disruption induced by high glucose plus IL-1β is prevented by Epo through the downstream signaling of JAK2 and PI3K/AKT pathways.

Topics: Calcium; Cell Count; Cell Line, Tumor; Chromones; Dextrans; Diabetic Retinopathy; Erythropoietin; Fluorescein-5-isothiocyanate; Glucose; Humans; Immunoblotting; Immunohistochemistry; Interleukin-1beta; Janus Kinase 2; Membrane Proteins; Morpholines; Permeability; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protective Agents; Retinal Pigment Epithelium; Signal Transduction; Tyrphostins

Diabetic retinopathy is characterized by pericyte loss and vasoregression both in the clinic and in animal models. A mild neurodegeneration with loss of ganglion cells is also described in the diabetic retina. Like VEGF-A, Epo is angioprotective and, in high doses, neuroprotective, however, without affecting vessel permeability. This study was to investigate the effect of a long-term suberythropoietic dose of Epo on vascular damage and neurodegeneration in a rat model of diabetic retinopathy.. We administered Epo 3x256 IU/kg body weight/week to streptozotocin-diabetic Wistar rats for up to 6 months. Leukostasis was analyzed by quantitation of CD45 positive cells adherent to the retinal microvasculature. VEGF-A levels were assessed by Elisa at 3 months of treatment. Vasoregression was quantified in retinal digest preparations after 6 months of Epo treatment. Neurodegeneration was analyzed from PAS stained retinal paraffin preparations.. Leukostasis was unaffected by treatment with Epo which significantly inhibited the loss of pericyte and the formation of acellular capillaries. Neurodegeneration in the diabetic retina was significantly reduced by Epo treatment. Increased VEGF-A levels in the diabetic retina were normalized by Epo treatment.. Suberythropoietic Epo is effective to protect microvascular and neuronal damage in the experimental diabetic retina.

Topics: Animals; Base Sequence; Blood Glucose; Diabetes Mellitus, Experimental; Diabetic Retinopathy; DNA Primers; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Male; Neuroprotective Agents; Rats; Rats, Wistar

To investigate the possible involvement of erythr opoietin (EPO)/erythropoietin receptor (EPOR) system in neovascularization and vascular regeneration in diabetic retinopathy (DR).. EPOR positive circulating progenitor cells (CPCs: CD34(+)) and endothelial progenitor cells (EPCs: CD34(+)KDR(+)) were assessed by flow cytometry in type 2 diabetic patients with different stages of DR. The cohort consisted of age- and sex-matched control patients with out diabetes ( n=7),non-proliferative DR (NPDR, n=7),non-proliferative DR (PDR, n=8), and PDR complicated with diabetic nephr opathy (PDR-DN, n=7).. The numbers of EPOR(+) CPCs and EPOR(+) EPCs were reduced remarkably in NPDR compared with the control group (both Pü0.01), whereas rebounded in PDR and PDR-DN groups in varyingdegrees. Similar changes were observed in respect of the proportion of EPOR(+)CPCs in CPCs (NPDR vs. control, Pü0.01) and that of EPOR(+) EPCs in EPCs (NPDR vs. control, Pü0.05).. Exogenous EPO, mediated via the EPO/EPOR system of EPCs, may alleviate the impaired vascular regeneration in NPDR, whereas it might aggravate retinal neovascularization in PDR due to a rebound of EPOR(+)EPCs associated with ischemia.

Topics: Aged; Cell Count; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Endothelium, Vascular; Erythropoietin; Female; Humans; Male; Middle Aged; Receptors, Erythropoietin; Stem Cells

To determine the aqueous humour levels of vascular endothelial growth factor (VEGF) and erythropoietin (EPO) in eyes with diabetic macular oedema before and after intravitreal EPO injection.. Prospective interventional case series.. Eleven eyes of 11 patients with diabetic macular oedema, and 10 eyes of 10 patients with cataract surgery as controls.. EPO and VEGF levels in aqueous humour before and after intravitreal EPO injection in patients and compared with controls.. Eyes with diabetic macular oedema received an intravitreal injection of EPO (1000 IU/0.05 mL), followed by various intraocular procedures at different intervals (1-54 days) after injection. An aqueous humour sample was obtained and aqueous humour levels of EPO and VEGF were measured using enzyme-linked immunosorbent assay.. The aqueous levels of EPO and VEGF were significantly elevated in diabetic macular oedema eyes compared to control eyes (P < 0.05). EPO levels in patients correlated with VEGF levels (r = 0.816, P = 0.002) and central macular thickness at baseline (r = 0.618, P = 0.043). After intravitreal EPO injection, aqueous EPO levels were significantly elevated, whereas aqueous VEGF levels were varied according to the time interval since injection. Visual acuity and central macular thickness were not different after injection, compared to before injection. Aqueous EPO levels did not correlate with serum EPO levels(r = 0.299, P = 0.371).. EPO is locally expressed and is correlated with VEGF in eyes with diabetic macular oedema. The role of EPO and the effect of intravitreal EPO in patients with diabetic macular oedema need to be further defined.

Topics: Adult; Aqueous Humor; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Epoetin Alfa; Erythropoietin; Female; Fluorescein Angiography; Humans; Intravitreal Injections; Macular Edema; Male; Middle Aged; Prospective Studies; Recombinant Proteins; Tomography, Optical Coherence; Vascular Endothelial Growth Factor A; Visual Acuity

Erythropoietin (EPO) may be protective for early stage diabetic retinopathy, although there are concerns that it could exacerbate retinal angiogenesis and thrombosis. A peptide based on the EPO helix-B domain (helix B-surface peptide [pHBSP]) is nonerythrogenic but retains tissue-protective properties, and this study evaluates its therapeutic potential in diabetic retinopathy.. After 6 months of streptozotocin-induced diabetes, rats (n = 12) and age-matched nondiabetic controls (n = 12) were evenly split into pHBSP and scrambled peptide groups and injected daily (10 μg/kg per day) for 1 month. The retina was investigated for glial dysfunction, microglial activation, and neuronal DNA damage. The vasculature was dual stained with isolectin and collagen IV. Retinal cytokine expression was quantified using real-time RT-PCR. In parallel, oxygen-induced retinopathy (OIR) was used to evaluate the effects of pHBSP on retinal ischemia and neovascularization (1-30 μg/kg pHBSP or control peptide).. pHBSP or scrambled peptide treatment did not alter hematocrit. In the diabetic retina, Müller glial expression of glial fibrillary acidic protein was increased when compared with nondiabetic controls, but pHBSP significantly reduced this stress-related response (P < 0.001). CD11b+ microglia and proinflammatory cytokines were elevated in diabetic retina responses, and some of these responses were attenuated by pHBSP (P < 0.01-0.001). pHBSP significantly reduced diabetes-linked DNA damage as determined by 8-hydroxydeoxyguanosine and transferase-mediated dUTP nick-end labeling positivity and also prevented acellular capillary formation (P < 0.05). In OIR, pHBSP had no effect on preretinal neovascularization at any dose.. Treatment with an EPO-derived peptide after diabetes is fully established can significantly protect against neuroglial and vascular degenerative pathology without altering hematocrit or exacerbating neovascularization. These findings have therapeutic implications for disorders such as diabetic retinopathy.

Topics: Animals; Animals, Newborn; Apoptosis; Cytokines; Diabetic Retinopathy; DNA Damage; Erythropoietin; Gene Expression Regulation; Ischemia; Male; Mice; Mice, Inbred C57BL; Nerve Degeneration; Neuroglia; Peptide Fragments; Protein Interaction Domains and Motifs; Random Allocation; Rats; Rats, Sprague-Dawley; Retina; Retinal Degeneration; Retinal Vessels

To determine whether sequence variation in the erythropoietin gene (EPO) is associated with the development of diabetic retinopathy (DR).. This was a multicenter study based on 518 subjects with long-standing diabetes mellitus (DM), 173 with type 1 DM (T1DM) and 345 with type 2 DM (T2DM). Study groups consisted of 233 control subjects with no DR, 155 subjects with nonproliferative DR, 126 with proliferative DR, and 90 with clinically significant macular edema. Subjects with end-stage renal disease were excluded. DNA extracted from blood of each subject was genotyped for 3 EPO single-nucleotide polymorphisms (SNPs).. All 3 SNPs in EPO were associated with overall DR status in the combined T1DM and T2DM and T2DM alone groups (CC genotype of rs507392, P < .008; GG genotype of rs1617640, P < .008; and CC genotype of rs551238, P < .008) in the multivariate analysis. The GCC haplotype was also associated with overall DR status in the combined DM and T2DM alone groups (P = .008) by multivariate analysis. All SNPs and the GCC haplotype were also associated with proliferative DR and clinically significant macular edema in the combined DM and T2DM alone groups. No associations were found with T1DM alone.. Sequence variation in EPO is associated with the risk of DR independent of duration of DM, degree of glycemic control, and nephropathy.. Identifying EPO genetic markers for high risk of developing DR could lead to the possibility of developing novel treatments or preventive therapies.

Topics: Adult; Blood Pressure; Body Mass Index; Cholesterol; Creatinine; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Erythropoietin; Female; Genotype; Glycated Hemoglobin; Humans; Male; Middle Aged; Polymorphism, Single Nucleotide; Risk Factors

A molecular hyperspectral imaging (MHI) system was developed to evaluate the protective effects of erythropoietin (EPO) on early diabetic retinopathy in rats. The system was used to capture hyperspectral images of rat retinal sections selected from three groups: normal control, diabetic, and EPO. Three biochemical parameters were defined, namely, the spectral transmittance index, thickness of outer nuclear layer, and cell area percentage. The corresponding algorithms to calculate these were likewise presented. Experimental results show that, after treatment, the newly defined biochemical parameters of the EPO group become more similar to those of the normal control group compared with those of the diabetic group. This indicates that, to some degree, EPO provides protective effects on the retinal cells of chemically induced diabetic rats after it is injected intravitreally at the onset of diabetes. The results likewise show that the MHI system could provide useful quantitative information regarding retinal sections, which ophthalmologists can use to determine the pathogenesis of diabetic retinopathy and evaluate the protective effect of EPO on diabetic retinal cells.

Topics: Animals; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Erythropoietin; Histocytochemistry; Male; Molecular Imaging; Protective Agents; Rats; Rats, Wistar; Retina; Spectrum Analysis

Diabetic retinopathy is the result of increased oxidative and nitrosative stress induced by chronic hyperglycaemia, and affects the vasculature and the neuroglia. Erythropoietin is a neuroprotective and an endothelial survival factor. We assessed the effect of suberythropoietic epoetin delta doses on variables of oxidative stress in target tissues of diabetic complications and on pericyte loss in the diabetic retina.. We administered epoetin delta to streptozotocin-induced diabetic Wistar rats at doses of 384 IU/kg body weight once weekly or 128 IU/kg body weight three times a week. The treatment lasted for 3 months. Oxidative stress and formation of AGEs were assessed by immunoblotting, expression of Ang-2 (also known as Angpt2) by RT-PCR, activation of protein kinase B (AKT) and heat shock protein (HSP)-27 levels by immunofluorescence, and incipient retinal vascular changes by quantitative morphometry of retinal digest preparations.. Diabetes increased variables of oxidative stress and nitrosative stress (N(epsilon)-carboxymethyl-lysine, nitrotyrosine and methylglyoxal-type AGEs) in retina, kidney and heart of diabetic rats. Epoetin delta reduced oxidative and nitrosative stress in all tissues, and AGEs in the retina. It also reduced increased retinal Ang-2 expression and pericyte loss, and ameliorated p-AKT and HSP-27 levels.. Epoetin delta has antioxidative properties in organs affected by diabetes and may prevent incipient microvascular damage in the diabetic retina.

Topics: Analysis of Variance; Angiopoietin-2; Animals; Blood Glucose; Blotting, Western; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Erythropoiesis; Erythropoietin; Fluorescent Antibody Technique; Male; Oxidative Stress; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Retina; Retinal Vessels; Reverse Transcriptase Polymerase Chain Reaction

In the present study, a single intravitreal erythropoietin (EPO) to diabetic rats produced therapeutic effects on blood-retinal barrier (BRB) function and neuronal survival at different time courses of retinopathy. In parallel, the hypoxia-inducible factor 1 alpha (HIF-1 alpha) pathway has been quantitatively studied, including VEGF-A, endogenous EPO, EPO receptor (EpoR), prolyl hydroxylases (PHD1-3) and von Hippel-Lindau tumor suppressor (VHL). The mRNA levels of HIF-1 alpha, VEGF-A, endogenous EPO, PHD1-3 and VHL are all up-regulated in the diabetic retina, and suppressed by exogenous EPO. The increased protein levels of HIF-1 alpha, VEGF-A, and endogenous EPO found in diabetic retinas also have been down-regulated by exogenous EPO. The results demonstrate that the HIF-1 pathway is activated in the retina in early diabetes, but is negatively regulated by a feedback loop following the administration of exogenous EPO. Exogenous EPO at pharmacologic levels leads to suppression of VEGF and in turn, restoration of the normal functions of BRB in a time-dependent manner. In the diabetic retina, the same level of exogenous EPO that inhibits VEGF also exerted neuronal protection.

Topics: Animals; Base Sequence; Blood-Retinal Barrier; Diabetic Retinopathy; DNA Primers; Erythropoietin; In Situ Nick-End Labeling; Male; Microscopy, Electron; Polymerase Chain Reaction; Rats; Rats, Sprague-Dawley; Vascular Endothelial Growth Factor A; Vitreous Body

Topics: Anemia; Diabetic Nephropathies; Diabetic Retinopathy; Erythropoietin; Humans

In a recent study, we found high levels of erythropoietin (EPO) in patients with diabetic macular oedema (DME), suggesting a role of EPO in the pathogenesis of this condition. To investigate a possible relationship between EPO and other diseases causing macular oedema, we determined vitreous levels of this peptide in patients with macular oedema secondary to retinal vein occlusion (RVO) and compared them with levels in patients with DME and control patients.. Vitreous and serum samples were obtained from patients with macular oedema secondary to RVO, DME, epiretinal membrane, and macular hole (controls). EPO was measured by radioimmunoassay.. No differences were found in median vitreous EPO levels between patients with RVO and controls: RVO, 76 mU/ml (30-806) vs controls, 25 mU/ml (10-75) (P=0.105). Median EPO concentration was higher in DME patients than in patients with RVO or controls: DME, 430 mU/ml (41-3000) vs RVO, 76 mU/ml (30-806) (P<0.0001) vs controls, 25 mU/ml (10-75) (P<0.0001).. EPO levels are not elevated in patients with macular oedema secondary to RVO. Patients with DME have high levels of EPO. These results suggest that EPO could be involved in the pathogenesis of diabetic retinopathy, but not in macular oedema secondary to RVO.

Topics: Aged; Biomarkers; Diabetic Retinopathy; Erythropoietin; Female; Humans; Macular Edema; Male; Middle Aged; Radioimmunoassay; Retinal Vein Occlusion; Vitreous Body

Topics: Diabetic Retinopathy; Erythropoietin; Humans; Macular Edema

Angiogenic factors such as vascular endothelial growth factor (VEGF), erythropoietin, and angiopoietin play important roles in the development of diabetic retinopathy. However, the suppression of a single factor does not inhibit angiogenesis completely. This study simultaneously evaluated the expression of several angiogenic factors in the retinas of diabetes-induced rats and determined the effects of an angiotensin-converting enzyme inhibitor (enalapril) on the expression of angiogenic factors.. Diabetes was chemically induced by injecting 14 of 21 Sprague-Dawley rats with streptozotocin. After induction of diabetes, enalapril (10 mg/kg) was administered orally to seven rats. The rats were divided into normal, diabetes mellitus (DM), and enalapril-treated groups (each group, n = 7). The eyeballs were removed at 8 weeks after the induction of diabetes, and the retinal expression of VEGF, the signal transducer and activator of transcription (STAT)3/5, erythropoietin, and angiopoietin were examined using immunohistochemistry, RT-PCR, and Western blotting.. RT-PCR revealed that the expression of VEGF, VEGF receptors, STAT3, erythropoietin, erythropoietin receptor, STAT5, angiopoietin 2, and Tie2 mRNA increased in the DM group, whereas angiopoietin 1 expression decreased. The enalapril-treated group showed no increase in mRNA expression of angiogenic factors. Immunohistochemical staining and Western blotting showed that the expression of VEGF, STAT3, and erythropoietin receptor proteins increased in the DM group but not in the enalapril-treated group. Erythropoietin and angiopoietin proteins were not detected by immunohistochemical staining or Western blotting. STAT5 protein expression was detected only in the DM group using immunohistochemical staining and Western blotting. The mRNA expression of the angiogenic factors VEGF, erythropoietin, and angiopoietin 2 increased in the DM group but not in the enalapril-treated group. In contrast, angiopoietin 1 mRNA expression decreased in the DM group.. Enalapril treatment prevented increased angiogenic factor levels in the retinas of experimentally induced diabetic rats.

Topics: Angiogenic Proteins; Angiopoietin-1; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Glucose; Blotting, Western; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Enalapril; Erythropoietin; Immunoenzyme Techniques; Male; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; STAT3 Transcription Factor; STAT5 Transcription Factor; Vascular Endothelial Growth Factor A

A molecular spectral imaging system has been developed based on microscopy and spectral imaging technology. The system is capable of acquiring molecular spectral images from 400 nm to 800 nm with 2 nm wavelength increments. The basic principles, instrumental systems, and system calibration method as well as its applications for the calculation of the stain-uptake by tissues are introduced. As a case study, the system is used for determining the pathogenesis of diabetic retinopathy and evaluating the therapeutic effects of erythropoietin. Some molecular spectral images of retinal sections of normal, diabetic, and treated rats were collected and analyzed. The typical transmittance curves of positive spots stained for albumin and advanced glycation end products are retrieved from molecular spectral data with the spectral response calibration algorithm. To explore and evaluate the protective effect of erythropoietin (EPO) on retinal albumin leakage of streptozotocin-induced diabetic rats, an algorithm based on Beer-Lambert's law is presented. The algorithm can assess the uptake by histologic retinal sections of stains used in quantitative pathology to label albumin leakage and advanced glycation end products formation. Experimental results show that the system is helpful for the ophthalmologist to reveal the pathogenesis of diabetic retinopathy and explore the protective effect of erythropoietin on retinal cells of diabetic rats. It also highlights the potential of molecular spectral imaging technology to provide more effective and reliable diagnostic criteria in pathology.

Topics: Albumins; Algorithms; Animals; Diabetic Retinopathy; Equipment Design; Erythropoietin; Glycation End Products, Advanced; Image Processing, Computer-Assisted; Immunohistochemistry; Male; Microscopy; Rats; Rats, Sprague-Dawley; Retina

Topics: Diabetic Retinopathy; Erythropoietin; Humans; Macular Edema; Somatostatin; Vitreous Body

The purpose of this study was to investigate the efficacy of recombinant human erythropoietin (rhEPO) in preventing and reversing dysfunction of retinal neurons and glial cells in early-stage streptozotocin (STZ)-induced diabetic rats. Two weeks after STZ [60 mg/kg body weight (b.w.), i.p.] injection, diabetic rats had been administered rhEPO (5000 IU/kg of b.w., i.p.) injection three times weekly for 2 weeks. The changes to the electroretinogram, retina ultrastructure, erythropoietin receptors (EPO-Rs) and the content of glutamate in retinas before and after the experiment in test and control groups were compared. The amplitudes of b-wave and oscillatory potentials (OPs) decreased at the end of the experiment in STZ-induced diabetic rats compared with the age-matched controls, whereas the amplitudes of b-wave and OPs showed no decrease in diabetic rats with rhEPO injection. Mitochondrial metamorphosis in ganglion cells occurred in STZ-induced diabetic rats but was not found in those rats with rhEPO treatment. EPO-Rs in retinas and the retinal glutamate of STZ-induced diabetic rats at the end of the experiment had increased obviously compared with rhEPO-injected diabetic rats. The abnormalities of retinal electrophysiological activity, ganglion cells with swollen mitochondria in the retinas, increased retinal glutamate and EPO-R in the retinas occurred early in the process of the disease course in diabetic rats. These aspects can all be improved by intraperitoneal administered rhEPO. The administration of rhEPO may be useful in the neural treatment of diabetic retinopathy at the early stage.

Topics: Animals; Chromatography, High Pressure Liquid; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Electroretinography; Erythropoietin; Glutamic Acid; Microscopy, Electron; Mitochondria; Neuroglia; Rats; Rats, Sprague-Dawley; Receptors, Erythropoietin; Recombinant Proteins; Retina; Retinal Ganglion Cells

To explore and evaluate the protective effect of erythropoietin (EPO) on retinal cells of chemically induced diabetic rats after EPO was injected intravitreally at the onset of diabetes.. Diabetes was induced in Sprague-Dawley rats by intraperitoneal injection of streptozotocin (STZ). At the onset of diabetes, a single intravitreal injection of EPO (0.05-200 ng/eye) was performed. In the following 6 weeks, the blood retinal barrier (BRB) was evaluated by Evans blue permeation (EBP). Retinal cell death in different layers was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. The retinal thickness and cell counts were examined at the light microscopic level. Electron microscopy (EM) was used to scrutinize retinal vascular and neuronal injury. Neurosensory retinas of normal and diabetic rats were used as the sources of reverse transcription-polymerase chain reaction (RT-PCR) and Western blot for the detection of EPO, EPO receptor (EpoR), and products of the extracellular signal-regulated kinase (ERK) and the signal transducers and activators of transcription 5 (STAT5) pathways. The distribution of EpoR in retinal layers was demonstrated by immunohistochemistry (IHC).. In the diabetic rats, BRB breakdown was detected soon after the onset of diabetes, peaked at 2 weeks, and reached a plateau at 2 to 4 weeks. The number of TUNEL-positive cells increased in the neurosensory retina, especially, the outer nuclear layer (ONL) at 1 week after diabetes onset and reached a peak at 4 to 6 weeks. The retinal thickness and the number of cells in the ONL were reduced significantly. EM observations demonstrated vascular and photoreceptor cell death starting soon after the onset of diabetes. All these changes were largely prevented by EPO treatment. Upregulation of EpoR in the neurosensory retina was detected at both the transcriptional and protein levels 4 to 8 weeks after the onset of diabetes, whereas, the endogenous EPO levels of neurosensory retinas were essentially unchanged during the same period observed. In EPO-treated diabetic groups, EpoR expression remained at upregulated levels. Within 2 weeks of the onset of diabetes, activation of the ERK but not the STAT5 pathway was detected in the diabetic retina treated with EPO.. These data demonstrate that apoptosis is an major contributor to neuronal cell death in the early course of diabetic retinopathy (DR). The upregulation of EpoR may be a compensatory response of retinal cells and tissue to diabetic stresses. The EPO/EpoR system as a maintenance-survival mechanism of retinal neurons responds to the insults of early diabetes other than ischemia. The protective function of EPO/EpoR at the least acts through the EpoR-mediated ERK pathway. Exogenous EPO administration by intravitreal injection in early diabetes may prevent retinal cell death and protect the BRB function. Therefore, this is a novel approach for treatment of early DR.

Topics: Animals; Apoptosis; Blood-Retinal Barrier; Blotting, Western; Capillary Permeability; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Erythropoietin; Evans Blue; Immunoenzyme Techniques; In Situ Nick-End Labeling; Injections; Male; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Neurons; Rats; Rats, Sprague-Dawley; Receptors, Erythropoietin; Retinal Vessels; Reverse Transcriptase Polymerase Chain Reaction; STAT5 Transcription Factor; Vitreous Body

To measure erythropoietin (Epo) levels in the vitreous body from patients with proliferative diabetic retinopathy (PDR).. Undiluted vitreous samples were obtained from 44 patients who had not undergone prior vitreous or intraocular surgery. Patients were divided into two groups: A (n= 24) patients with PDR and B (n= 20) patients with retinal detachment, preretinal macular membranes and macular holes. Epo was determined using radioimmunoassay.. Epo vitreous concentration in group A was 512 mU/mL (range 120-880) and in group B was 25.1 mU/mL (range 5.2-201) (p< 0.001).. These results show that the concentration of Epo in the vitreous body was significantly higher in patients with PDR than in the control group.

Topics: Aged; Diabetic Retinopathy; Erythropoietin; Female; Humans; Male; Middle Aged; Vitreous Body

Topics: Diabetic Retinopathy; Disease Progression; Erythropoietin; Humans; Kidney Failure, Chronic; Receptors, Erythropoietin; Recombinant Proteins

Significant morbidity and mortality among patients with diabetes mellitus result largely from a greatly increased incidence of microvascular complications. Proliferative diabetic retinopathy (PDR) and end stage renal disease (ESRD) are two of the most common and severe microvascular complications of diabetes. A high concordance exists in the development of PDR and ESRD in diabetic patients, as well as strong familial aggregation of these complications, suggesting a common underlying genetic mechanism. However, the precise gene(s) and genetic variant(s) involved remain largely unknown. Erythropoietin (EPO) is a potent angiogenic factor observed in the diabetic human and mouse eye. By a combination of case-control association and functional studies, we demonstrate that the T allele of SNP rs1617640 in the promoter of the EPO gene is significantly associated with PDR and ESRD in three European-American cohorts [Utah: P = 1.91 x 10(-3); Genetics of Kidneys in Diabetes (GoKinD) Study: P = 2.66 x 10(-8); and Boston: P = 2.1 x 10(-2)]. The EPO concentration in human vitreous body was 7.5-fold higher in normal subjects with the TT risk genotype than in those with the GG genotype. Computational analysis suggests that the risk allele (T) of rs1617640 creates a matrix match with the EVI1/MEL1 or AP1 binding site, accounting for an observed 25-fold enhancement of luciferase reporter expression as compared with the G allele. These results suggest that rs1617640 in the EPO promoter is significantly associated with PDR and ESRD. This study identifies a disease risk-associated gene and potential pathway mediating severe diabetic microvascular complications.

Topics: Alleles; Animals; Cell Line; Cohort Studies; Diabetic Nephropathies; Diabetic Retinopathy; Erythropoietin; Gene Expression Regulation; Genes, Reporter; Genetic Predisposition to Disease; Haplotypes; Humans; Kidney; Luciferases; Mice; Polymorphism, Single Nucleotide; Promoter Regions, Genetic; Retina; RNA, Messenger

To investigate the expression of the hypoxia-inducible factor-1alpha (HIF-1alpha) and the protein products of its target genes vascular endothelial growth factor (VEGF), erythropoietin (Epo) and angiopoietins (Angs), and the antiangiogenic pigment epithelium-derived factor (PEDF) in proliferative diabetic retinopathy (PDR) epiretinal membranes.. Sixteen membranes were studied by immunohistochemical techniques.. Vascular endothelial cells expressed HIF-1alpha, Ang-2 and VEGF in 15 (93.75%), 6 (37.5%) and 9 (56.25%) membranes, respectively. There was no immunoreactivity for Epo, Ang-1 and PEDF. There were significant correlations between the number of blood vessels expressing the panendothelial marker CD34 and the numbers of blood vessels expressing HIF-1alpha (r = 0.554; p = 0.026), Ang-2 (r = 0.830; p<0.001) and VEGF (r = 0.743; p = 0.001). The numbers of blood vessels expressing Ang-2 and VEGF in active membranes were higher than that in inactive membranes (p = 0.015 and 0.028, respectively).. HIF-1alpha, Ang-2 and VEGF may play an important role in the pathogenesis of PDR. The findings suggest an adverse angiogenic milieu in PDR epiretinal membranes favouring aberrant neovascularisation and endothelial abnormalities.

Topics: Angiopoietin-2; Antigens, CD34; Cell Division; Diabetic Retinopathy; Epiretinal Membrane; Erythropoietin; Eye Proteins; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Immunoenzyme Techniques; Ki-67 Antigen; Nerve Growth Factors; Serpins; Vascular Endothelial Growth Factor A

The purpose of this study was to evaluate whether the concentration of erythropoietin as another potent ischemia-induced angiogenic factor is elevated in eyes with neovascular (age-related macular degeneration [AMD]) or oedematous (diabetic retinopathy) maculopathies. The clinical comparative study included 28 patients with diabetic macular oedema, 59 patients with exudative AMD, and 49 patients with cataract. For all patients, aqueous humour was collected during cataract surgery or during an intravitreal injection of triamcinolone acetonide. Erythropoietin levels were measured using a solid-phase chemiluminescence immunoassay. The mean concentration of erythropoietin was significantly higher in the diabetic group (60.1 +/- 46.7 mUnits/mL; P < 0.001) than in the age-related macular degeneration group (22.9 +/- 23.2 mUnits/mL) and in the control group (22.0 +/- 21.0 mUnits/mL; P < 0.001). The two latter groups did not vary significantly (P = 0.41). The results indicate that erythropoietin may be present in considerably higher concentrations in eyes with diabetic macular oedema than in eyes with exudative AMD or normal eyes.

Topics: Aged; Aqueous Humor; Cataract; Diabetic Retinopathy; Erythropoietin; Exudates and Transudates; Humans; Luminescent Measurements; Macular Degeneration; Macular Edema

Diabetic retinopathy is a leading cause of visual disturbance in adults. In proliferative diabetic retinopathy, ischemia-induced pathologic growth of new blood vessels often causes catastrophic loss of vision. Besides VEGF, the existence of another potent ischemia-induced angiogenic factor is postulated. Since ischemia-inducible erythropoietin (Epo) has recently been identified its angiogenic properties, we investigated its potential role during retinal angiogenesis in proliferative diabetic retinopathy (PDR). The vitreous Epo level in patients with PDR was significantly higher than that in nondiabetic patients. Multivariate logistic regression analyses indicated that Epo and VEGF were independently associated with PDR and that Epo was more strongly associated with PDR than VEGF. Blockade of Epo inhibits retinal neovascularization in vivo, and inhibits endothelial cell proliferation response to PDR vitreous in vitro. Our data provide strong evidence that erythropoietin is a potent retinal angiogenic factor independent of VEGF and is capable of stimulating ischemia-induced retinal angiogenesis in proliferative diabetic retinopathy. Inhibition of such molecular mechanisms in the retinal angiogenesis could be a new therapeutical strategy in halting or preventing pathologic angiogenesis in diabetic retinopathy.

Topics: Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Humans; Neovascularization, Pathologic; Retinal Vessels; RNA, Messenger; Vascular Diseases; Vascular Endothelial Growth Factor A

The present study investigated the relationship between hemoglobin (Hb) levels and autonomic failure using a sensitive marker, coefficient of variation of R-R intervals in electrocardiogram (CVR-R) in order to clarify a cause of normocytic normochromic anemia in type 1 diabetic patients without overt nephropathy. We recruited 46 patients with type 1 diabetes and measured creatinine clearance (Ccr), HbA1c, albuminuria, Hb levels and CVR-R of all patients. In addition, the status of diabetic retinopathy and neuropathy were also evaluated. Serum erythropoietin (EPO), Fe, total iron binding capacity, lactate dehydrogenase, total bilirubin levels and number of reticulocytes and mean corpuscular volume were also measured to distinguish types of anemia. To survey the statistical correlation existing between Hb and body mass index (BMI), Ccr, HbA1c, albuminuria or retinopathy, multiple regression analysis was performed. Serum EPO, Fe, TIBC, LDH and TB levels and number of reticulocytes and MCV were within normal limits. Multiple regression analysis disclosed that HbA1c, nephropathy evaluated by albuminuria and Ccr, and retinopathy has no concern with Hb level. There is only significant relationship between Hb levels and CVR-R. Similar results were obtained even if we analyzed a group of male and female separately. We conclude that CVR-R has the strong relationship on anemia without overt nephropathy in type 1 diabetes, indicating that autonomic failure contributes on the progression of anemia via a poor response of EPO to anemia.

Topics: Adult; Aged; Albuminuria; Anemia; C-Peptide; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Diabetic Neuropathies; Diabetic Retinopathy; Electrocardiography; Erythropoietin; Female; Glycated Hemoglobin; Humans; Male; Middle Aged; Sensitivity and Specificity

It is widely accepted that intravitreous levels of erythropoietin (Epo) are elevated in patients with ischaemic retinal diseases such as proliferative diabetic retinopathy (PDR). The aim of this study was to examine the expression of Epo and the Epo receptor (EpoR) in epiretinal membranes with and without diabetes.. Eighteen epiretinal membranes (PDR (n = 10), idiopathic epiretinal membranes (IERMs) without diabetes (n = 4) and inner limiting membranes (ILMs) (n = 4)) were obtained during pars plana vitrectomy. Formalin-fixed and paraffin-embedded tissues were examined by immunohistochemistry with anti-Epo and EpoR antibodies.. The histopathological findings demonstrated that PDR membranes consisted of a variety of endothelial cells forming a microvascular cavity with red blood cells and non-vascular stromal mononuclear cells. Membranous and cytoplasmic immunoreactivity for EpoR was strongly detected in endothelial cells and stromal cells in all PDR patients. Although microvessels were not observed in IERMs and ILMs, immunoreactivity for EpoR was noted in the cellular component of IERMs, and was weakly detected in ILMs. Epo was not expressed in any membrane.. EpoR was strongly expressed in microvessels of all PDR membranes. The in vivo evidence in this study suggests that Epo in the vitreous binds to EpoR in PDR membranes, which subsequently leads to the proliferation of new retinal vessels. EpoR immunoreactivity in non-vascular stromal cells in PDR membranes, and IERMs and ILMs might be indirectly correlated with ischaemia.

Topics: Aged; Diabetic Retinopathy; Endothelial Cells; Epiretinal Membrane; Erythropoietin; Female; Humans; Immunohistochemistry; Male; Microcirculation; Middle Aged; Receptors, Erythropoietin

Before the clinical availability of erythropoietin, diabetic retinopathy was known to stabilize on dialysis. Recently erythropoietin has been shown to be a potent angiogenic factor. Therefore, we chose to examine whether severity and progression of diabetic retinopathy has been accelerated by the administration of recombinant erythropoietin to patients with chronic renal failure.. Records of the patients followed by the Hypertension Nephrology, Dialysis, and Transplantation Clinic, the regional nephrology referral center for Eastern Alabama, from 1982 through 2005 were reviewed. Funduscopic examination at the time of ESRD was ranked according to the proposed international scale for severity of clinical diabetic retinopathy. Forty-five patients from the era before the availability of erythropoietin were matched to 45 patients from 2002 to 2004 who had been given erythropoietin but had similar prevalence of proliferative retinopathy, neuropathy, and years of diabetes before the onset of end-stage renal disease. Progression of retinopathy was compared according to multivariate analysis with 2-tailed Pearson correlation coefficient.. There was significantly greater deterioration of retinopathy at 1 year in the patients who had received erythropoietin (P = 0.004). Although the presence of retinopathy at ESRD correlated with known traditional risk factors such as years of diabetes, age, and serum cholesterol, the deterioration of retinopathy after the initiation of hemodialysis correlated only with hematocrit (P = 0.042) and most significantly total dose of erythropoietin (P = 0.001).. The prevalence and severity of proliferative retinopathy appear to have increased and are most closely associated with the erythropoietin dosing.

Topics: Anemia; Blood Glucose; Blood Pressure; Case-Control Studies; Cholesterol; Diabetic Retinopathy; Disease Progression; Dose-Response Relationship, Drug; Erythropoietin; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Multivariate Analysis; Prevalence; Renal Dialysis; Retrospective Studies; Risk Factors; Severity of Illness Index

Although retinal neovascularization in proliferative diabetic retinopathy(PDR) is a major cause of legal blindness, its mechanism is not fully understood. In this study, we focused on the angiogenic activity of erythropoietin (Epo) and evaluated its potential role in treating retinal angiogenesis in PDR.. We measured Epo and vascular endothelial growth factor (VEGF) levels in the vitreous fluids of 73 PDR patients and 71 nondiabetic (NDM) patients. We evaluated Epo expression and regulation in retinal neovascularization with soluble Epo receptor.. The vitreous Epo level was significantly higher in patients with PDR than in NDM patients. Multivariate logistic-regression analyses indicated that Epo and VEGF were independently associated with PDR and that Epo was more strongly associated with PDR than VEGF was. The blockade of Epo inhibited retinal neovascularization in vitro and in vivo.. Our data suggest that Epo is a potent angiogenic factor that acts independently of VEGF during retinal angiogenesis in PDR.

Topics: Diabetic Retinopathy; Erythropoietin; Female; Humans; Male; Middle Aged; Neovascularization, Pathologic; Retina

Retinal neovascularization in diabetes has been thought to follow the release of local angiogenic factors in the retina. We hypothesize that neovascularization of diabetic retinopathy is a systemic vasculogenesis rather than a local angiogenesis. Thus, we evaluate the concentrations of circulating endothelial progenitor cells (EPCs) and stem cell modulation factors such as vascular endothelial growth factor (VEGF), erythropoietin (Epo), and substance p (SP) in the peripheral blood of diabetic retinopathy patients.. We studied 15 normal controls and 45 type II diabetic patients (no DR group (n=15), NPDR group (n=15), and PDR group (n=15)). We measured circulating CD34+mononuclear cells (CD34+MNCs), c-Kit+mononuclear cells (c-Kit+MNCs) by flow cytometry. VEGF, Epo, and SP in the peripheral blood were measured by ELISA.. The circulating CD34+MNCs and c-Kit+MNCs increased in the NPDR and PDR groups compared with the control group (P<0.01). Serum level of VEGF increased in the NPDR and PDR groups compared with the control group (P<0.05). The level of Epo elevated exclusively in the no DR group compared with the other three groups (P<0.01). Circulating SP level increased in the NPDR and PDR groups compared with the control group (P<0.05). SP and CD34+MNCs were shown to have increased correlation according to the diabetic retinopathy in the NPDR and PDR groups (r=0.440, P<0.05 and r=0.460, P<0.05, respectively).. The present study is the first to demonstrate that CD34+MNCs, c-Kit+MNCs and their modulator are elevated in diabetic retinopathy patients. Therefore, it is possible that circulating EPCs and serum Epo, VEGF, and SP may be involved in the progression of diabetic retinopathy.

Topics: Aged; Aged, 80 and over; Angiogenesis Inducing Agents; Antigens, CD34; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Endothelium, Vascular; Erythropoietin; Female; Humans; Leukocytes, Mononuclear; Male; Middle Aged; Retinal Neovascularization; Severity of Illness Index; Stem Cells; Substance P; Vascular Endothelial Growth Factor A

Erythropoietin has been recently found to be increased in the vitreous fluid from ischemic retinal diseases such as proliferative diabetic retinopathy (PDR). The aims of the present study were 1) to measure erythropoietin levels in the vitreous fluid from patients with diabetic macular edema (DME), a condition in which the ischemia is not a predominant event, and 2) to compare erythropoietin mRNA expression between human retinas from nondiabetic and diabetic donors without retinopathy.. Vitreous samples from 12 type 2 diabetic patients with DME without significant retinal ischemia and 12 PDR patients were prospectively analyzed. Ten nondiabetic patients with macular holes served as the control group. Erythropoietin was assessed by radioimmunoassay (milliunits per milliliter). Erythropoietin mRNA expression was measured by quantitative real-time RT-PCR analysis in the retina from eight nondiabetic and eight age-matched diabetic donors without diabetic retinopathy. Intravitreal erythropoietin concentration was higher in both PDR and DME patients than in nondiabetic control subjects (PDR vs. control subjects: median 302 [range 117-1,850] vs. 30 mU/ml [10-75], P < 0.01; DME vs. control subjects: 430 [41-3,000] vs. 30 mU/ml [10-75], P < 0.01). However, no significant differences were found between DME and PDR patients. Erythropoietin mRNA expression was detected in the human retina, and it was higher in the retina from diabetic than from nondiabetic donors.. As occurs in PDR, intravitreous erythropoietin concentrations are strikingly higher in DME. Erythropoietin is expressed in the human retina, and it is upregulated in diabetic patients even without retinopathy. These findings suggest that other factors apart from ischemia are involved in the overexpression of erythropoietin in diabetic retinopathy.

Topics: Aged; Case-Control Studies; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Erythropoietin; Female; Humans; Macular Edema; Male; Middle Aged; Prospective Studies; Radioimmunoassay; Retina; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

Although vascular endothelial growth factor (VEGF) is a primary mediator of retinal angiogenesis, VEGF inhibition alone is insufficient to prevent retinal neovascularization. Hence, it is postulated that there are other potent ischemia-induced angiogenic factors. Erythropoietin possesses angiogenic activity, but its potential role in ocular angiogenesis is not established.. We measured both erythropoietin and VEGF levels in the vitreous fluid of 144 patients with the use of radioimmunoassay and enzyme-linked immunosorbent assay. Vitreous proliferative potential was measured according to the growth of retinal endothelial cells in vitro and with soluble erythropoietin receptor. In addition, a murine model of ischemia-induced retinal neovascularization was used to evaluate erythropoietin expression and regulation in vivo.. The median vitreous erythropoietin level in 73 patients with proliferative diabetic retinopathy was significantly higher than that in 71 patients without diabetes (464.0 vs. 36.5 mIU per milliliter, P<0.001). The median VEGF level in patients with retinopathy was also significantly higher than that in patients without diabetes (345.0 vs. 3.9 pg per milliliter, P<0.001). Multivariate logistic-regression analyses indicated that erythropoietin and VEGF were independently associated with proliferative diabetic retinopathy and that erythropoietin was more strongly associated with the presence of proliferative diabetic retinopathy than was VEGF. Erythropoietin and VEGF gene-expression levels are up-regulated in the murine ischemic retina, and the blockade of erythropoietin inhibits retinal neovascularization in vivo and endothelial-cell proliferation in the vitreous of patients with diabetic retinopathy in vitro.. Our data suggest that erythropoietin is a potent ischemia-induced angiogenic factor that acts independently of VEGF during retinal angiogenesis in proliferative diabetic retinopathy.

Topics: Animals; Case-Control Studies; Cattle; Cell Proliferation; Cells, Cultured; Diabetic Retinopathy; Dose-Response Relationship, Drug; Erythropoietin; Extracellular Matrix Proteins; Female; Humans; Logistic Models; Male; Mice; Middle Aged; Myosin Heavy Chains; Nonmuscle Myosin Type IIB; Proteins; Receptors, Erythropoietin; Retina; Retinal Neovascularization; RNA, Messenger; Up-Regulation; Vascular Endothelial Growth Factor A; Vitreous Body

Topics: Diabetic Retinopathy; Erythropoietin; Humans; Retina; Retinal Neovascularization; Vascular Endothelial Growth Factor A

Topics: Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Humans; Hypoxia; Vascular Endothelial Growth Factor A; Vitreous Body

Topics: Analysis of Variance; Diabetic Retinopathy; Erythropoietin; Humans; Infant, Newborn; Infant, Very Low Birth Weight; Retinal Neovascularization; Retinopathy of Prematurity; Risk Factors

Topics: Anemia; Diabetic Nephropathies; Diabetic Retinopathy; Disease Progression; Erythrocyte Aggregation; Erythropoietin; Humans; Recombinant Proteins; Risk Factors

Coincidental with the pandemic growth of diabetes as the prime cause of end-stage renal disease (ESRD), blindness attributable to diabetic retinopathy has become a major concern for all those involved in the care of diabetic ESRD patients. Vision loss is linked to progression of proliferative retinopathy and macular edema.. Extracted from a study of azotemic anemic pre-ESRD patients treated with erythropoietin, a cohort of five diabetic subjects was reassessed in terms of stability of renal function, changes in blood rheology, and course of diabetic eye disease.. All subjects reported subjective improvement in well-being, including enhanced effort tolerance following an increase in hematocrit from a baseline level of to 29.6 +/- 2.0% to a level of 39.5 +/- 2.4% after one year of treatment with erythropoietin (P = <0.0005). Neither hypertension nor deterioration of renal function was noted in any subject. Three patients with macular edema evinced substantive improvement-based stable vision and documented resolution noted in flourescein angiography.. Erythropoietin treatment of anemic azotemic diabetic patients is well tolerated. In a small observational retrospective study of three patients with macular edema, retention of vision and resolution of exudates was noted.

Topics: Anemia; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Diabetic Retinopathy; Erythropoietin; Female; Humans; Middle Aged; Papilledema; Uremia

We report the case of a 52-year-old woman with long-term type 1 diabetes mellitus, complicated with proliferative retinopathy, autonomic neuropathy and microalbuminuria and moderate renal failure. A normochromic, normocytic are generative anaemia had been diagnosed for three years. Clinical and biological investigations for the aetiology of anaemia remained normal or negative. Anaemia was associated with a concentration of erythropoietin (EPO) in the normal range, but inappropriately low regarding anaemia. Treatment with recombinant EPO induced a rapid increase in haemoglobin level and improved the patient's quality of life. The role of diabetic neuropathy in the genesis of anaemia, in conjunction with a modest renal impairment is discussed.

Topics: Albuminuria; Anemia; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Diabetic Neuropathies; Diabetic Retinopathy; Electrocardiography; Erythropoietin; Female; Hemoglobins; Humans; Hypotension, Orthostatic; Kidney Failure, Chronic; Middle Aged; Quality of Life; Recombinant Proteins

Diabetic retinopathy improved in three patients with renal insufficiency after a rise in hematocrit induced by administration of recombinant erythropoietin. The change involved significant resorption of hard exudates in patients who were not eligible to receive laser treatment.. Three patients with diabetic nephropathy had the associated chronic anemia of renal insufficiency. In each patient, diabetic retinopathy with foveal/parafoveal hard exudates (but no clinically significant macular edema) was initially evaluated ophthalmoscopically. Fluorescein angiography demonstrated a low-grade diffuse leakage pattern. Treatment with subcutaneous recombinant erythropoietin (4000 IU twice weekly) was initiated within 1 to 3 months of initial evaluation. The resolution of hard exudates was observed on ophthalmoscopic examination and graded fundus photography (ETDRS seven standard field).. Within 6 months of initiation of erythropoietin treatment, a substantial reduction of exudate was observed in all three patients, the hematocrit having increased from a mean of 21% to a mean of 33% (a mean increase of 33% in each patient). Visual acuity improved in two patients and stabilized in the other. Follow-up fluorescein angiographic examination demonstrated no change in the leakage pattern.. Although no direct cause and effect relationship can be established, raising the red cell mass by treatment with recombinant erythropoietin may serve as adjunctive treatment of diabetic retinopathy in patients with diabetic renal insufficiency.

Topics: Absorption; Anemia; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Diabetic Retinopathy; Erythropoietin; Exudates and Transudates; Female; Fundus Oculi; Humans; Injections, Subcutaneous; Kidney Failure, Chronic; Middle Aged; Recombinant Proteins