Hormone receptors in the retina

Sex hormones and sex hormone receptors are present in the retina from an early stage. Many areas of the brain and retina develop in a sexually dimorphic manner during prenatal, perinatal and postnatal development. Salyer et al. using Long-Evans rats found that prenatally and early postnatally in normal rats males had thicker retinas than females. This increased thickness was reduced using flutamide, an androgen inhibitor, but not significantly so compared to normal males or testosterone-treated...

Clinical implication and current treatment modalities of diabetic inner BRB dysfunction Diabetic macular edema

Macular edema which resulted from the dysfunctional BRB is the most common cause of visual disturbance in patients with nonproliferative diabetic retinopathy (NPDR). In addition to the disruption of inner BRB of the pre-existing retinal vasculature, the 'leaky' property of new vessels contributes to the macular edema in patients with proliferative diabetic retinopathy (PDR). Breakdown of BRB causes retention of fluid and plasma contents, such as lipoproteins within neural retina leading to...

Pathogenic implications of NO deficiency

Vascular deficiency of NO may be critical for pathogenesis of micro and macrovascular complications of non-controlled diabetes mellitus (15). This may be appreciated in the light of physiological importance of basal activity of NO in maintaining an appropriate arteriolar vasodilation, stabilizing platelets and preventing excessive activation and circulating leucocyte adhesion (15). Loss of such activity may clearly promote ischaemia by inducing arteriolar vasoconstriction and microvascular...

Advanced Glycation end products AGEs

AGE's are formed via non-enzymatic condensation reaction between reducing glucoses and amine residues of proteins, lipids or nucleic acids that undergo a series of complex reaction to give irreversible cross linked complex group of compounds termed as AGEs. Some of the best chemically characterized AGEs in human are carboxymethyllysine (CML), carboxyethyllysine (CEL), and pentosidine which act a markers for formation and accumulation of AGE in hyperglycemia. CML and other AGEs have been...

Vitamin C 101 Introduction

Vitamin C (ascorbic acid) is an essential micronutrient for normal body metabolism and it is present in fresh fruits, particularly in citrus ones, and in vegetables (15). Its deficiency causes scurvy (22). Minimum necessary requirement of vitamin C is 60 mg day for health and non-smoker people (22). Vitamin C is a co-factor of several enzymes 1. Pro-collagen-proline dehidrogenase (proline dehidrogenase) and procollagen lisine 5-dehidrogenase (lysine desidrogenase), involved in pro-collagen...

Enhancement of nitric oxide synthase activity in endothelial cells

The term endothelium-derived relaxing factor was originally proposed by Robert Furchgott for a then unknown factor leading to relaxation of the smooth muscle of large arteries in response to acetylcholine. Nitric oxide NO, which is in fact a free radical, was later found to be the mediator of this response. Most of NO in the body is synthesized by the endothelial isoform of NO synthase (NOS) from its precursor L-arginine (Palmer et al., 1988a), which is inhibited by false substrates of NOS,...

Insulin like Growth Factor IGFI

IGF-I is a polypeptide showing high similarity to insulin. Two different forms are distinguished IGF-I and IGF-II. IGF-I circulates in blood in the form of IGF-binding protein (IGF-BP), probably inhibiting activity of free IGF. IGF-I is a pivotal growth factor secreted as a result of stimulation by human growth hormone. Both in vivo and in vitro studies indicate its anti-apoptotic and anti-inflammatory properties (Goes et al., 1996 Sukhanov et al., 2007 Sun et al., 2010). There are reports that...

References

P., Miller, J.W., Bernal, M.T., D'Amico, D.J., Folkman J., Yeo T.K. & K. Yeo T. (1994) Increased vascular endothelial growth factor levels in the vitreous of eyes with proliferative diabetic retinopathy. Am J Ophthalmol, Vol. 118, No. 4 (October 1994), pp. 445-450, ISSN 0002-9394 Adamis, A. P., Shima, D.T., Tolentino, M.J., Gragoudas, E.S., Ferrara, N., Folkman J., D'Amore, P.A. & Miller J.W. (1996) Inhibition of vascular endothelial growth factor prevents retinal...

Insulinlike Growth Factor1 IGF1

Similar to VEGF, the activation of IGF-1 also increases PKC activation, so IGF-1 may be regulated by oxidative stress via the PKC pathway89. Retinal IGF-1 mRNA levels are lower in the human and diabetic rat when compared to age matched non-diabetic controls90 and IGF-1 can have direct mitogenic effects on retinal EC60.IGF-1 can stimulate glucose transport into retinal microvascular EC via activation of PKC and can modulate the expression and activity of VEGF91. Growth hormone and IGF-I have...

INOS

Inducible isoform of nitric oxide synthase(iNOS) expression is regulated at least in part by NF-k B. Interestingly, experimental sympathectomy itself increases gene and protein expression of iNOS in retinas of nondiabetic rats145, suggesting that loss of sympathetic activity, such as which occurs in diabetes, might contribute to the upregulation of this inflammatory protein in the retina. In retinas of diabetic animals, increased levels of nitric oxide products (nitrotyrosine, nitrite, nitrate)...

Conclusion

There are evidences of a key-role of free radicals in diabetic retinopathy pathogenesis. Retina is rich in polyunsaturated fat acids and presents glucose oxidation and oxygen caption taxes greater than any other tissue, being, this way, extremely susceptible to increased oxidative stress. Alterations of enzyme activity of antioxidant system (such as superoxide dismutase) seem to be one of the possible sources of oxidative stress in diabetes. Recent evidences also point to a participation of...

Renin Angiotensin System RAS

Hypertension has been identified as a major risk factor of microvascular complications leading to small vessel dysfunction, manifesting the state of diabetic retinopathy. In patients with diabetic retinopathy, tight control of blood pressure delays the progression of the disease and growing evidence suggests that RAS plays an important role in the regulation of blood pressure. The RAS is an enzymatic cascade in which angiotensinogen is the precursor of the angiotensin peptides. The cascade...

Alterations of blood flux regulation

Endothelins are the main endothelial vasoconstrictors (12). In endothelial cells of retinal vessels, main endothelin is the subtype ET-1, that is synthethized and released by the action of several factors (growth factors, cytokines and insulin, among others) and is negativelly controlled by prostaciclin, nitric oxide and heparin, among other substances (12). ET-1 interacts with specific membrane receptors that are present in vascular smooth muscle fibers (ETA and ETB) and it triggers a...

Intracellular transportation of vitamin C

It is known the existence of two distict mechanisms of vitamin C transportation into the cells (25) 1. A sodium-dependent mechanism that is mediated by a pair of ascorbate carriers, which is predominant in hemato-encephalic barrier, osteoblasts, muscles, placenta, intestine walls, brush border kidney cells, liver, brain and in the majority of endocrine and neuroendocrine systems, and it is not affected by glucose plasmatic levels (25) 2. An extremely sensible mechanism to glucose blood levels...

Vitamin C and nitric oxide

Other studies demonstrated that vitamin C restores endothelium depending vasodilation in diabetic type 1 patients and in acute hyperglycemia in health humans, while studies realized with type 2 diabetics showed varied results (24). Several mechanisms may be responsible for such effects and, probably, they are related to vitamin C antioxidant activity (22). NO presents an important role in vasodilation and it also inhibits platelet aggregation and lecocyte adhesion (22). Studies showed that NO...

OCT interpretation quantitative analysis

The quantitative analysis is a very important part of OCT interpretation. Quantitative measurements of retinal thickness, volume, and a variety of structures (i.e. retinal morphometry) provide objective information for diagnosing disease, tracking disease progress, and evaluating response to therapy. The availability of highly reproducible and repeatable retinal thickness measurements (DRCRN, 2007 Paunescu et al., 2004 Puliafito et al., 1995) is prerequisite for early diagnosis of macular...

Correlation filters set

The goal in this stage is to get the set of candidate red lesions. Since the regions corresponding to lesions have a wide variety of sizes, three correlation filters with different resolutions, Fj, F2 and F3, are applied to the image. As proposed in Niemeijer et al. (2005), since red lesions have the highest contrast in the green plane Hoover & Goldbaum (2000), in place of applying the correlation to the gray-level version of the image, green plane Ig is used as the input. In Figure 3 the...

Neuronal damage in diabetic retinopathy 71 Neurodegeneration

A pathogenic mechanism of nerve damage in diabetic retinopathy begins shortly after the onset of diabetes. Several clinical tools such as multifocal electroretinography (ERG), flash ERG, contrast sensitivity, color vision, and short-wavelength automated perimetry, all detect neuronal dysfunction at early stages of diabetes Han Y, 2004 Bearse MA, 2004 Fletcher EL, 2007 . Occurrence of many functional changes in the retina can be identified before the development of vascular pathology, suggesting...

HMGCoA reductase inhibitor Atorvastin

Lipids have a definite role in the pathogenesis of diabetic retinopathy. Because of the increased permeability and leakage of the retinal capillaries, extravascular deposition of less soluble plasma lipoprotein occurs. The mass of lipid-filled macrophages is visible on funduscopy as hard exudates (Watanabe et al., 1988). Statins act by competitively inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, the first committed enzyme of the HMG-CoA reductase pathway. Sen et al. found...

Nonsteroidal antiinflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly prescribed classes of medications worldwide. Aspirin and other chemically related compounds, used systemically for many decades for their analgesic, antipyretic, and anti-inflammatory properties, have more recently been prepared in topical ophthalmic formulations. As such, they have proven useful to enhance mydriasis, reduce postoperative inflammation, and prevent and treat cystoid macular edema (CME) associated with...

Sex differences in the prevalence of retinopathy noted in epidemiological studies

The role of gender as a contributing factor in diabetic retinopathy has long been debated. Numerous and seemingly contradictory studies have shown either a male predisposition, a female predisposition, or no significant difference between the sexes in development or progression of diabetic retinopathy. Earlier population studies such as the Wisconsin Epidemiological Study of Diabetic Retinopathy (WESDR) were done with predominantly white cohorts (Klein et al. 2008 Klein et al. 2010). The 25...

Introduction

Diabetic retinopathy (DR) is the leading cause of blindness in working-age individuals. There is increasing evidence that established risk factors for DR, including duration of diabetes, hyperglycemia, and hypertension, only explain a limited amount of the variance in the risk of DR. Furthermore, the underlying pathogenesis of DR remains inadequately understood. Diabetes causes metabolic and physiologic abnormalities in the retina, and these changes suggest a role for inflammation in the...

Lowering RAGE expression

Several commonly used therapeutic agents showed effects on the reduction of RAGE expression in vascular endothelial cell thiazolidinediones (rosiglitazone and pioglitazone), calcium channel blocker (nifedipine), angiotensin II receptor blocker (telmisartan). Rosiglitazone and pioglitazone, kinds of thiazolidinediones, an anti-diabetic drug act by binding to peroxisome proliferator-activated receptors reduces basal and tumor necrosis factor-a stimulated expression of RAGE in cultured human...

Physiopathology of diabetes chronic complications

According to what has already been said, diabetes chronic complications occur as a consequence of persistent hyperglycemia (7). Hyperglycemia, in turn, promotes glucose auto-oxidation, AGEs formation and its interaction with RAGEs, activation of several isoformes of PKC, induction of poliol pathway and an increase of flux of hexosamine pathway (7). Recently, it was made a hypothesis according to which all these processes would be a consequence of an increase of superoxide production by...

Puberty

While the levels of sex hormones increase during puberty, it is important to remember that the levels of growth hormones and secondary growth factors also increase during puberty. In fact Merimee reported a clinical observation that diabetic dwarfs exhibit little retinopathy (Merimee 1990). Another interesting clinical observation reported by Bell in a case study of agonadal (without ovaries) female twins demonstrated a lack of retinopathy after a long duration of very poorly controlled...

Epidemiology

International epidemiological studies indicate that over the last 50 years there has been progressive raise in diabetes incidence. According to International Diabetes Federation (IDF) currently there are 284 millions of people affected by diabetes worldwide and IDF prognosis predicts that in 2030 this number for all countries and human races will reach 438 million which will account for 7.7 of global population (IDF Atlas, 2010). The highest prevalence of diabetes is in North America where it...

Neuron

Retinal blood flow is tightly regulated according to the activity of retinal neurons. Metabolic need of ganglion cells is supposed to be an important factor in vascular development of retina. Intercellular communications between endothelial cells, M ller cells and neurons are expected to play a pivotal role in the formation and functioning of BRB. Diabetic retinopathy is a kind of progressive neuropathy. Retinal neuropathy in diabetes could be a consequence of preceding diabetic vascuopathy....

Adiponectin ADPN

The adipocyte derived factor ADPN is an insulin sensitivity activator, and is correlated to retinal redox stress and remodeling in metabolic syndrome and T2DM. Low levels of serum ADPN levels were found to be correlated with the severity of retinopathy60. Insulin-sensitizing agents reduce pathological retinal microvessel formation through ADPN mediated modulation of tumor necrosis factor alpha (TNFa) production61. ADPN' s effect on diabetic retinopathy is not clear. However, ADPN induces eNO...

Blood flow velocity measurement in patients with diabetes mellitus

The diabetic pathological processes, which initially are subtle, affect retinal hemodynamics. In the normal retina, autoregulated vascular responses keep the blood flow constant over a range of systemic blood pressures and intraocular pressures (Riva, et al., 1981, Robinson, et al., 1986). Vessels are controlled through local factors, (Haefliger & Anderson, 1997, Matsugi, et al., 1997a, atsugi, et al., 1997b, Riva et al., 1981, Shepro & Morel, 1993) which primarily target smooth muscle...

Lipids

Brown et al. found a marked accumulation of retinal exudate in patients with high triglyceride levels (Brown et al. 1984). Dodson and Gibson in a study on patients with type 2 diabetes found that hypercholesterolemia was a risk factor in the development of diabetic maculopathy (Dodson and Gibson 1991). In epidemiological studies Chew et al., and Klein et al. found that increased blood lipid levels are associated with diabetic retinopathy in that subjects with elevated lipids had a greater risk...

Hepatocyte Growth Factor HGF

HGF in the etiopathogenesis of PDR remains to be elucidated. A lot of studies165-169 have found high intravitreous concentrations of HGF in patients with PDR. In the present study, we consider all these confounding factors in order to evaluate the vitreous levels of HGF in patients with PDR and to investigate its relationship with VEGF and retinopathy activity. A total of 28 diabetic patients with PDR, in whom a vitrectomy was performed, were included in the study. Thirty nondiabetic patients...

Pathophysiology

Diabetic macular edema is a microvascular complication of diabetes mellitus with serious implications for vision loss. The central pathophysiologic event is retinal capillary incompetence and leakage. Several biochemical hypotheses exist to explain the damage to retinal capillary constituents in diabetes mellitus. Prolonged hyperglycemia has been implicated in direct injury to retinal capillary endothelial cell and pericytes and to a decline in cell division (Engerman 1987). Cells in the body...

OCT interpretation qualitative analysis morphology and reflectivity

While performing qualitative analysis one should simultaneously perform morphological examination (changes in retinal profile - surface and posterior layers, and presence of abnormal structures) and reflectivity examination (hyper-reflectivity, hypo-reflectivity, and shadowing effects) (Brancato & Lumbroso, 2004). Pathological changes in retinal surface contour may represent disappearance of the normal foveal depression (in macular edema). Steepening of the foveal contour may be associated...

Subthreshold Micropulse Diode Laser Photocoagulation SMDLP

Many laser modalities such as argon blue-green, argon green, krypton and diode have been used to achieve a clinically visible burn (threshold burn) according to the conventional photocoagulation protocol (Akduman & Olk, 1997 Olk, 1990). Subthreshold micropulse diode laser photocoagulation (SMDLP) is designed to target the retinal pigment epithelium while minimizing the negative thermal effects on the neural retina and deeper structures. A micropulse diode laser allows subthreshold therapy...

Transforming Growth Factor beta TGFP

TGF-P is a member of transforming growth factor family which has immunomodulatory function. It is secreted primarily by monocytes, macrophages, lymphocytes, and dendritic cells. This cytokine takes part in angiogenesis, stimulates synthesis and degeneration of extracellular matrix proteins, regulates induction of apoptosis and stimulates proliferation of mesenchymal cells. TGF-P exists in three isoforms coded by different genes p1, p2, p3 best known is TGF- p1 (Bertolino et al., 2005 Orlova et...

Hexosamine pathway

The hexosamine biosynthesis pathway is another hyperglycemic induced pathway which has been implicated in diabetic pathogenesis Giacco F, 2010 . Increased expression of an enzyme called GFAT (glutamine fructose-6 phosphate amidotransferase) causes the diversion of some of glycolytic metabolites such as fructose-6 phosphate to the hexosamine pathway producing UDP (uridine diphosphate)-N-acetylglucosamine which is a substrate used for the post-translational modification of intracellular factors...

Pigmented Epitelium Derived Factor PEDF

Besides causing vascular lesion, diabetes also presents an adverse and early impact over neural retina (2,12,18). Studies with diabetic patients showed early alterations in visual function, including damage of colored vision and contrast sensibility, and reduction of electroretinogram oscilatory potentials (2,12,18). Such alterations frequently precede microvascular lesions establishment and predict retinopathy worsening in a better way than clinical characteristics, suggesting that...

Autoantibodies in diabetes complications

The lack of an immune response to self when responses to environmental antigens are retained is due to immunological tolerance. The role of tolerance, or lack of tolerance, is important to the understanding of autoimmune diseases and transplantation immunobiology (Mackay 2000). A loss of natural tolerance (to self) underlies all autoimmune diseases. Many more individuals develop autoimmune phenomena than autoimmune disease. Immune-mediated (Type I) diabetes results from an organ-specific...

Triamcinolobe Acetonide For Crohns Disease Conclution

Although, focal laser photocoagulation is the standard-of-care treatment for DME, it is not a cure. During the last decade, a number of additional treatments for DME have been proposed. Such treatments include intravitreal injection of corticosteroids such as triamcinolone acetonide, intravitreal injection of aptamers or antibodies targeted at VEGF, vitrectomy, and pharmacologic therapy with oral protein kinase C beta inhibitors. In particular, anti-VEGF therapies, in conjunction with laser or...

Management

The Early Treatment in Diabetic Retinopathy Study (ETDRS), sponsored by the National Eye Institute in 1979, was a benchmark in the management of diabetic macular edema (ETDRS 1985). The ETDRS was a large-scale, multicenter, randomized clinical trial designed to investigate whether early treatment of macular edema by focal argon laser photocoagulation could prevent moderate visual loss, defined as a loss of three lines of vision or a doubling of the visual angle. Eyes with macular edema in the...

Hormones

Several hormones such as insulin, aldosterone, adrenomesdulin, growth hormone (GH) and endothelin have been found to be implicated in diabetic retinopathy Wilkinson-Berka JL, 2008 . Insulin stimulates anabolic functions and prevents the breakdown of skeletal muscle tissue. In diabetes, the loss of insulin signaling profoundly alters carbohydrate, lipids, amino acids and protein metabolism in a range of tissues including retina, altering nutrients pool and resulting in metabolic dysregulation...

Pigmented Epithelial Derived Factor PEDF

PEDF is a member of the serine protease inhibitor (serpin) superfamily with neurotrophic and antiangiogenic properties, and a decreased level of PEDF in the eye is important in the pathogenesis of proliferative DR40. In the retina, angiogenesis is regulated by two counterbalancing systems angiogenic stimulators, such as VEGF, and angiogenic inhibitors, such as angiostatin and pigment epithelium-derived factor (PEDF)40. PEDF is a natural extracellular component of the retina and has been found...

Focal grid laser photocoagulation

Focal Grid Laser

To characterize the severity of macular edema and for treatment guidelines, the term clinically significant macular edema (CSME) is defined retinal thickening at or within 500 m of the foveal center, hard exudates at or within 500 m of the foveal center with adjacent retinal thickening, or retinal thickening greater than 1 disc diameter in size, within 1 disc diameter of the foveal center (ETDRS group, 1985, 1987a). There is good evidence that focal laser treatment preserves vision in eyes with...

Abbreviations

ACE, angiotension converting enzyme AGE, advanced glycation end-products AR, androgen receptor Akt, serine threonine protein kinase CNV, choroidal neovascularization COX, cyclooxygenase CVD, cardiovascular disease DHEA, dehydroepiandrosterone DHT, dihydrotestosterone DIEP, Diabetes in Early Pregnancy Study E, estrogens E2, 17p-estradiol EDRF, endothelium-derived relaxing factor ETDRS, Early Treatment of Diabetic Retinopathy Study eNOS, endothelial nitric oxide synthase ER, estrogen receptor...

Blood flow velocity in patients with Diabetic retinopathy DR

To study the effect of DR on the retinal blood flow velocity 42 diabetic patients (58 eyes) and 32 healthy subjects (51 eyes) were recruited (Burgansky-Eliash, et al., 2010). All of the patients in that study group were suffering from adult-onset diabetic mellitus with moderate to severe NPDR in the study eye(s) (ETDRS categories D or E). All subjects were scanned using the RFI resulting in simultaneous measurement of blood-flow velocities in multiple macular vascular segments. In addition,...

Influence of calcium dobesilate on platelets and blood viscosity

Platelet-active drugs are in general of potential benefit in the prevention of diabetic microangiopathy. Calcium dobesilate was shown to reduce aggregation and the release reaction induced by thrombin and collagen in rabbit platelets (Michal & Gotti, 1988). Calcium dobesilate also increased platelet cAMP concentrations in vitro and ex vivo probably through activation of adenylate cyclase (Michal and Gotti, 1988). In addition, this drug reduced platelet electrophoretic mobility (Heidrich et...

Autoantibodies against glucooxidative modified proteins in diabetic retinopathy

The autoantibodies have always been important for clinical interest due to their potential role in screening, diagnosis, monitoring treatment of effectiveness and prognosis. Non-enzymatic glycation of proteins can lead to the formation of reactive AGEs, which are thought to be implicated in the formation of micro- and macrovascular complications in diabetes mellitus. Proteins such as serum albumin, collagen, elastin, lens crystalline, are particularly susceptible to glucose modification (Festa...

Polyol pathway

In diabetes, hyperglycemia activates polyol pathway, where a part of excess glucose are metabolized to sorbitol which is then converted to fructose Lorenzi M, 2007 . Aldose reductase (AR) is the key and rate limiting enzyme in polyol pathway, and both galactose and glucose are substrates to this enzyme and compete with each other while being reduced to galactitol and sorbitol, respectively. Under physiological conditions glucose is poorly reduced by AR to sorbitol. By contrast, under diabetic...

Inflammation and diabetic retinopathy

Many of the molecular and functional changes that are characteristic of inflammation have been detected in retinas from diabetic animals or humans, and in retinal cells under diabetic conditions which support the potential role of proinflammatory cytokines, chemokines and other inflammatory markers in DR Adamis AP, 2008 . Joussen et al, have shown that CD18- - and ICAM-1- - mice have significantly fewer adherent leukocytes which is associated with fewer damaged endothelial cells and lesser...

Role of neurotrophic factors

Neurotrophic factors play important roles in regulating growth, maintenance and survival of neurons Mattson MP, 2004 . The role of brain derived neurotrophic factors (BDNF) in metabolism is supported by studies on BDNF-deficient mice which develop obesity and hyperphagia in early adulthood Kernie SG, 2000 whereas, when it administered to normal mice or rats, it has no effect on blood glucose levels, indicating that BDNF exerts its effects by enhancing insulin sensitivity Ono M, 1997 and...

Vascular tone

For some time a correlation between blood pressure and progression of retinopathy has been noted in epidemiologic studies demonstrating that lower blood pressures result in less diabetic retinopathy. This has now been confirmed by large randomized studies (Epidemiology of Diabetes Interventions and Complications (DCCT EDIC) Study Research Group 2005 The Diabetes Control and Complications Trial Group 1993 UK Prospective Diabetes Study Group 1998). It is well established that adolescent and...

Tumor Necrosis Factor alpha TNFa

TNF-a is one of most important inflammatory cytokines. It is produced primarily by monocytes and macrophages on which it exerts its endo-, para- and autocrine actions. It stimulates cytotoxic properties of monocytes and macrophages and simultaneously is a mediator of cytotoxicity. Its biological effects depends strongly on quantity and intensity of TNF-a secretion. Apart from taking part in inflammatory processes it also plays important role in neovascularisation (Wilson & Balkwill, 2002)....

Doxium For Varicose Veins

J. (2008). Immunological mechanisms in the pathogenesis of diabetic retinopathy. Semin Immunopathol, Vol. 30, No. 2, (April 2008), pp.(65-84), ISSN 1863-2297 Adank, C. & Koerner, F. (1985). Calcium dobesilate in diabetic retinopathy. A retrospective controlled study. Ophthalmologica, Vol. 190, No. 2, (February 1985), pp. (102-111), ISSN 0030-3755 Aiello, L.M (2003). Perspectives on diabetic retinopathy. American journal of ophthalmology, Vol. 136, No. 1, (July...

Fenofibrate

Because dyslipidemia is a well documented risk factor of diabetic macular edema and hard exudates deposition, lipid lowering treatment was expected to have benefit on these complications. The Fenofibrate Intervention and Event Lowering in Diabetes FIELD study group applicated fenofibrate, a peroxisome proliferator-activated receptor PPAR -a agonist which is widely used as lipid lowering agent in diabetic patients to reduce the risk of microvascular and macrovascular complications. PPAR-a...

Pharmacokinetics and metabolism of calcium dobesilate

Studies on the metabolism and pharmacokinetics of calcium dobesilate were carried out by Benakis and colleagues Benakis et al., 1974 . They reported the results of blood levels of calcium dobesilate labeled with 35S isotope, protein binding and urinary excretion in humans. The studies in humans were performed by the administration of the drug p.o. or i.v. After i.v. medication, 500 mg, the maximum value is obtained 5 min after administration and is about 65 mg ml. This value of dicreases...

Vitreoretinal interface and macular traction

Macular traction is a factor implemented in the pathogenesis of macular edema and there is increasing evidence that releasing it via vitrectomy may be beneficial DRCRN, 2010 Patel et al., 2006 Yanyali et al., 2007 . Macular traction may be induced by vitreoretinal interface abnormalities such as incomplete posterior vitreous detachment PVD or ERM. In 1984 Shepens and coauthors postulate the role of incomplete PVD in the formation or progression of macular edema in susceptible eyes, such as of...