fibrin and Diabetic-Retinopathy

Topics: Basement Membrane; Blood Platelets; Capillaries; Cholesterol; Diabetic Nephropathies; Diabetic Retinopathy; Endothelium; Erythrocytes; Fibrin; Glomerulonephritis; Hemosiderin; Humans; Hyalin; Lipids; Microscopy, Electron; Retinal Vessels

To report the intra-and postoperative complications and visual acuity outcomes in pars plana vitrectomy (PPV), phacoemulsification and intraocular lens (IOL) implantation in patients with cataract and proliferative diabetic retinopathy (PDR). A comparison of the combined versus two-step surgical approach is given.. Retrospective uncontrolled interventional clinical trial. Forty-eight eyes of 48 consecutive patients with PDR were included. Twenty-eight (58.3%) eyes with combined surgery and 20 (41.7%) eyes with sequential surgery were analyzed.. Postoperative follow-up time was between 6 and 63 months (mean: 18 months). 1) Combined surgery: Preoperative best-corrected visual acuity (BCVA) ranged from 20/200 to hand motions, and postoperative BCVA ranged from 20/30 to hand motions. BCVA improved in 17 eyes (60.7%), while in 7 (25%) eyes there was no change (> or =2 ETDRS lines) in VA, and in 4 (14.3%) eyes BCVA decreased. Postoperative complications included vitreous hemorrhage (VH) in 10 (35.7%) eyes, and fibrinous exudation in 9 (32.1%) eyes. 2) Two-step surgery: Preoperative BCVA ranged from 10/200 to light perception, and from 20/40 to light perception in the postoperative period. Best-corrected visual acuity improved in 15 (75%) eyes, remained the same in 4 (20%) eyes, and decreased in 1 (5%) eye. Postoperative complications included fibrinous exudation in 6 (30%) eyes, and VH in 3 (15%) eyes.. Combined PPV, phacoemulsification and IOL implantation as well as the two-step procedure are safe and effective for the management of cataract in PDR. Sequential surgery could be advantageous to BCVA outcomes by minimizing postoperative VH, which is significantly more frequent after combined surgery.

Topics: Adult; Aged; Aged, 80 and over; Cataract; Diabetic Retinopathy; Exudates and Transudates; Female; Fibrin; Follow-Up Studies; Humans; Intraoperative Complications; Ischemia; Lens Implantation, Intraocular; Macula Lutea; Male; Middle Aged; Phacoemulsification; Postoperative Complications; Retinal Detachment; Retrospective Studies; Time Factors; Visual Acuity; Vitrectomy; Vitreoretinopathy, Proliferative; Vitreous Hemorrhage

Proliferative diabetic retinopathy (PDR) represents a main cause of acquired blindness. Despite the recognition of the key role exerted by vascular endothelial growth factor (VEGF) in the pathogenesis of PDR, limitations to anti-VEGF therapies do exist. Thus, rapid and cost-effective angiogenesis assays are crucial for the screening of anti-angiogenic drug candidates for PDR therapy. In this context, evaluation of the angiogenic potential of PDR vitreous fluid may represent a valuable tool for preclinical assessment of angiostatic molecules. Here, vitreous fluid obtained from PDR patients after pars plana vitrectomy was used as a pro-angiogenic stimulus in a 3D endothelial cell spheroid/human vitreous assay. The results show that PDR vitreous is able to stimulate the sprouting of fibrin-embedded HUVEC spheroids in a time- and dose-dependent manner. A remarkable variability was observed among 40 individual vitreous fluid samples in terms of sprouting-inducing activity that was related, at least in part, to defined clinical features of the PDR patient. This activity was hampered by various extracellular and intracellular signaling pathway inhibitors, including the VEGF antagonist ranibizumab. When tested on 20 individual vitreous fluid samples, the inhibitory activity of ranibizumab ranged between 0 and 100% of the activity measured in the absence of the drug, reflecting a variable contribution of angiogenic mediators distinct from VEGF. In conclusion, the 3D endothelial cell spheroid/human vitreous assay represents a rapid and cost-effective experimental procedure suitable for the evaluation of the anti-angiogenic activity of novel extracellular and intracellular drug candidates, with possible implications for the therapy of PDR.

Topics: Aged; Angiogenesis Inhibitors; Biological Assay; Diabetic Retinopathy; Endothelial Cells; Female; Fibrin; Gels; Human Umbilical Vein Endothelial Cells; Humans; Male; Neovascularization, Pathologic; Ranibizumab; Spheroids, Cellular; Vitreous Body

Topics: Diabetes Mellitus, Type 2; Diabetic Retinopathy; Eye Diseases; Fibrin; Humans; Laser Coagulation; Macular Edema; Male; Middle Aged; Postoperative Complications; Tomography, Optical Coherence; Vitrectomy; Vitreous Body; Vitreous Hemorrhage

Topics: Diabetic Retinopathy; Endophthalmitis; Female; Fibrin; Humans; Male; Postoperative Complications; Vitrectomy; Vitreous Body

Topics: Diabetic Retinopathy; Endophthalmitis; Female; Fibrin; Humans; Male; Postoperative Complications; Vitrectomy; Vitreous Body

The development and progression of diabetic retinopathy (DR) in type 2 diabetes mellitus (T2DM) have been associated with poor glycaemic control, long disease duration and other clinical features. However, the pathogenesis of the complication is still poorly understood. As the formation of dense fibrin clots resistant to lysis has been described in diabetes patients, this study tested the hypothesis that altered clot structure and function are associated with DR in T2DM patients.. The study included 101 T2DM subjects without DR (NDR) and 60 with DR. Plasma fibrin-clot permeation was assessed using a pressure-driven system, and expressed as the permeation coefficient (K(s)), indicating pore size, and as the time required for a 50% decrease in clot turbidity (t(50%)) as a marker of susceptibility to fibrinolysis. All patients underwent ophthalmological examination. Clinical and biochemical co-variables were also measured. Determinants of DR were identified using stepwise, multivariable, logistic-regression analyses.. Patients with DR had lower clot permeability (K(s): 6.15 ± 1.18 vs. 7.53 ± 1.24 10(-9) cm(2); P < 0.0001) and slower fibrin-clot lysis (t(50%): 10.12 ± 1.24 vs. 9.12 ± 1.4 min; P < 0.0001) than NDR subjects. Logistic analysis revealed associations between DR and K(s), t(50%), fasting glucose and diabetes duration, as well as insulin treatment and statin non-use (P < 0.05). After adjusting for these variables as well as for age and gender, associations between K(s) and t(50%) with DR proved to be significant.. Formation of compact fibrin clots and impaired clot lysis are both associated with DR in T2DM patients. However, it is unclear whether these abnormalities lead to the development of DR or merely constitute a marker of its presence.

Topics: Biomarkers; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Retinopathy; Female; Fibrin; Humans; Male; Middle Aged; Risk Factors

To determine the maximum tolerated dose (MTD) of enoxaparin, a low molecular weight heparin (LMWH) was used during repeat vitrectomy for rhegmatogenous retinal detachment with proliferative vitreoretinopathy (PVR) and severe diabetic retinopathy.. From 25 patients, 29 eyes undergoing repeat vitrectomy for PVR (CP3 or greater) or severe diabetic retinopathy were included in the study. Patients had previously undergone an average of 2.1 previous vitrectomies (range 1-5). Enoxaparin was added to the infusion fluid in an escalating dose from 0.1 IU/ml to 6.0 IU/ml as tolerated. Intraoperative bleeding, postoperative fibrin, hyphema and vitreous hemorrhage were graded in an unmasked fashion using previously described grading scales.. All patients completed the study, and the study was able to achieve the 6.0 IU/ml maximum dose on the dose escalation schedule. No patient experienced dose-limiting toxicity. Analysis showed no increase in intraoperative bleeding complications between low dose (1.0 IU/ml) enoxaparin (Mann-Whitney Test, P=0.029).. Enoxaparin dose escalation did not result in a dose-dependent increase in acute side effects. The establishment of a well-tolerated dose of enoxaparin during repeat vitrectomy for PVR and severe diabetic retinopathy (6.0 IU/ml) provides a foundation for future studies.

Topics: Diabetic Retinopathy; Enoxaparin; Female; Fibrin; Fibrinolytic Agents; Humans; Hyphema; Infusion Pumps; Intraoperative Complications; Male; Maximum Tolerated Dose; Middle Aged; Prospective Studies; Reoperation; Vitrectomy; Vitreoretinopathy, Proliferative; Vitreous Hemorrhage

Human recombinant tissue plasminogen activator (25 micrograms) was injected into seven eyes of six patients who had developed massive fibrin deposition after vitrectomy surgery for diabetes. Six eyes had developed pupillary membranes and recurrence of tractional retinal detachment from fibrin membranes, and one eye had developed only a pupillary membrane. All pupillary membranes resolved within one hour of administration of tissue plasminogen activator, and five tractional retinal detachments resolved within 24 hours. All eyes developed evidence of intraocular bleeding after tissue plasminogen activator injection. Subsequently, six of seven eyes developed recurrence of fibrin accumulation and tractional retinal detachment.

Topics: Adult; Diabetic Retinopathy; Eye Diseases; Female; Fibrin; Hemorrhage; Humans; Male; Middle Aged; Postoperative Care; Postoperative Complications; Retinal Detachment; Tissue Plasminogen Activator; Vitrectomy

Transscleral cyclophotocoagulation was performed with a neodymium: YAG laser on five patients 24-72 hr before enucleation for a blind, painful eye. The thermal mode at 20 ms and a maximum offset between aiming and therapeutic beams were kept constant. Variable parameters evaluated were energy levels between 2 and 8 J and distance from the limbus of 0.5-3.0 mm. Because of the underlying distortion in three of the eyes, meaningful interpretation by light microscopic evaluation was possible only in the other two. This suggested that the early histologic hallmark of the procedure is similar to that previously observed in human autopsy eyes with ciliary epithelial damage and elevation from underlying tissue. In addition, fibrin and scant inflammatory cells were seen in the space between ciliary epithelium and stroma. Minimal damage was observed in the ciliary muscle. These findings suggest that direct damage to the ciliary epithelium is the most likely mechanism of reduced aqueous production by this cyclodestructive procedure. The findings also support the concept that an anterior placement of approximately 1.0-1.5 mm posterior to the limbus is most likely to damage the ciliary epithelium of the pars plicata.

Topics: Ciliary Body; Diabetic Retinopathy; Epithelium; Eye Enucleation; Fibrin; Glaucoma, Neovascular; Glaucoma, Open-Angle; Humans; Inflammation; Leukocytes; Light Coagulation; Sclera

This study reviewed the histopathology of endometrial curettings following spontaneous abortion in diabetics and controls. The two groups did not differ significantly for an array of histologic features. The relationships between histopathology and diabetic White class, diabetic nephropathy or retinopathy, first trimester hemoglobin A1 percentage, and first trimester serum magnesium level were studied. The only significant correlation found was between diabetic retinopathy and decidual congestion with the presence of venous fibrin.

Topics: Abortion, Spontaneous; Decidua; Diabetic Retinopathy; Endometrium; Female; Fibrin; Glycated Hemoglobin; Histocytochemistry; Humans; Magnesium; Pregnancy; Pregnancy in Diabetics

Estimations of soluble fibrin monomer complexes (SFMC) in plasma are a convenient index of thrombin activation. Renal venous-arterial differences in plasma SFMC concentrations were determined in 16 randomly chosen diabetic patients by sampling directly and simultaneously from the renal artery and vein according to the method of Seldinger. In all subjects, SFMC concentrations were higher in the renal vein than in the renal artery, indicating that the kidney is an important source of SFMC. Venous-arterial differences were markedly elevated in patients with severe renal and retinal microangiopathy coupled with hypertension. The hypothesis is advanced that elevated plasma SFMC levels lead to abnormal fibrin deposits in lesioned glomeruli and retinal vessels. It is postulated that plasma SFMC may be a useful parameter for the assessment of diabetic vascular complications.

Topics: Adult; Aged; Blood Pressure; Diabetic Angiopathies; Diabetic Retinopathy; Female; Fibrin; Fibrinogen; Humans; Kidney Glomerulus; Male; Middle Aged; Renal Artery; Renal Veins; Thrombin

We studied the relationship between plasma soluble fibrin monomer complexes (SFMC) and diabetic microangiopathy. SFMC concentrations were investigated in 7 patients with advanced retinopathy (group II) and in 10 patients with both retinopathy and proteinuria (group III), and also in 12 control patients (group I). The age of the patients in each group was similar and overnight fasting blood sugar levels were below 220 mg/dl. Group II had higher levels of SFMC (21.8-3.8 mg/dl) than group I (7.3-4.8 m/dl). Group III showed the higher value of blood urea nitrogen (BUN) than other groups and showed higher levels of SFMC (31.5-12.3 mg/dl) than group II. There was no significant correlation between the levels of SFMC and blood sugar, but positive correlation between BUN concentrations and SFMC was recognized in group III. Increasing of SFMC levels were correlated to fibrinogen (Fbg) levels in all subjects. There was no correlation between the levels of SFMC and antithrombin (AT-III) except in group II. The 24-h urinary protein was significantly correlative to SFMC, and Fbg was also considered to be closely associated with microangiopathy and act to promote it.

Topics: Adult; Aged; Blood Urea Nitrogen; Creatinine; Diabetic Angiopathies; Diabetic Retinopathy; Female; Fibrin; Fibrinogen; Humans; Macromolecular Substances; Male; Middle Aged; Proteinuria; Solubility

Two hundred eighty consecutive vitrectomies in diabetic patients were studied retrospectively. In 15 eyes, interlacing fibrin-like strands appeared on the surface of the retina and behind the iris plane from two to 14 days postoperatively. One or two days later, a gelatinous mass formed in the center of the vitreous activity, leading to the development of tractional retinal detachment and rubeosis iridis with neovascular glaucoma. Large doses of systemic and topical corticosteroids reversed the fulminating course of this complication in six of 15 eyes. The combination of lens surgery or scleral buckling procedure with vitrectomy, and the presence of retinal detachment preoperatively seemed to predispose to this complication. It is possible that multiple surgical procedures performed during the same operation cause an increase in vascular permeability resulting in the formation of a gelatinous, fibrin-like material in the diabetic eye.

Topics: Adult; Aged; Diabetic Retinopathy; Eye Diseases; Female; Fibrin; Glaucoma; Humans; Intraocular Pressure; Iris Diseases; Male; Middle Aged; Postoperative Complications; Retinal Detachment; Retrospective Studies; Syndrome; Vitreous Body

Data from the literature concerning the frequent lack of correlation between the clinical manifestations of diabetic neuropathy on the one hand and the morphofunctional status of the appropriate nerves, disorders in carbohydrate and lipid metabolism, and the influence of antidiabetic therapy on metabolism and the clinical picture of diabetic neuropathy on the other, are presented. In this connection, abundant evidence of frequent affection of various blood vessels, particularly small and smallest, in diabetic neuropathy is considered. But even these data attest to a non-infrequent lack in diabetic neuropathy of the involvement of the appropriate vessels, particularly the lack of basal membrane thickening which is a most common indication to the diabetic involvement of capillaries. Attention is drawn to the possible role of genetic heterogeneity of people with regard to the development of various forms of diabetic neuropathy.

Topics: Adult; Aged; Basement Membrane; Blood Vessels; Chronic Disease; Diabetic Angiopathies; Diabetic Neuropathies; Diabetic Retinopathy; Endothelium; Fibrin; Gangrene; Humans; Microcirculation; Middle Aged; Nerve Fibers; Nervous System

By means of an immunofluorescent technique, we found factors promoting blood coagulation and platelet adhesion in the intima of retinal vessels. These factors coexisted with other agents causing the opposite process, fibrin dissolution. The components of this vascular hemostatic balance are possibly involved in the thrombotic occlusion of the retinal vessels, their canalization, and in the pathogenesis of diabetic retinopathy.

Topics: Animals; Blood Coagulation; Diabetic Retinopathy; Endothelium; Factor VIII; Female; Fibrin; Fluorescent Antibody Technique; Hemostasis; Humans; Platelet Adhesiveness; Pregnancy; Rabbits; Retinal Vessels; Thrombosis

Topics: Adult; Age Factors; Aged; Arteries; Blood Flow Velocity; Blood Pressure; Blood Vessels; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetic Angiopathies; Diabetic Retinopathy; Female; Fibrin; Fibrinogen; Fibrinolysis; Humans; Leg; Male; Middle Aged; Obesity; Plasminogen; Plethysmography, Impedance; Regional Blood Flow; Thrombophlebitis