Bleeding phenotype and hemostatic evaluation by thrombin generation in children with Noonan syndrome: A prospective study.

BACKGROUND: This study aimed to evaluate the bleeding phenotype and to conduct a comprehensive hemostatic evaluation in individuals with Noonan syndrome (NS), a dominantly inherited disorder caused by pathogenic variants in genes associated with the Ras/MAPK signaling pathway. METHODS: Children with a genetically confirmed diagnosis of NS underwent clinical evaluation, routine laboratory tests, platelet function testing, and thrombin generation (TG) assessment. RESULTS: The study included 24 children. The most frequently reported bleeding symptoms were easy bruising and epistaxis, while bleeding complications were observed in 15% of surgical procedures. Various hemostatic abnormalities were identified, including platelet dysfunction, von Willebrand disease, and clotting factor deficiencies. Abnormal platelet function was observed in 50% of the patients, and significantly lower TG parameters were found compared to controls. However, no significant correlation was observed between bleeding symptoms and TG results. CONCLUSIONS: The study suggests that the bleeding diathesis in NS is multifactorial, involving both platelet dysfunction and deficiencies of plasma coagulation factors. The potential role of TG assay as an ancillary tool for predicting bleeding tendencies in individuals with NS undergoing surgery warrants further investigation.

Management of surgery in persons with hemophilia A receiving emicizumab prophylaxis: data from a national hemophilia treatment center.

Background: Persons with hemophilia A may require surgical procedures. Real-world data on invasive procedures in persons with hemophilia A receiving emicizumab prophylaxis are limited. Objectives: To evaluate the safety of invasive procedures in persons with hemophilia A receiving emicizumab prophylaxis and their outcomes in a longitudinally followed cohort. Methods: Data from medical records of persons with hemophilia A with and without factor VIII (FVIII) inhibitors longitudinally followed at our tertiary center, who received emicizumab prophylaxis and underwent all types of invasive procedures, were retrieved. Outcomes of interest were bleeding and thrombotic complications. Results: Overall, 35 patients underwent 56 invasive procedures, 18 (32.1%) were major. The median age was 36.3 years (IQR, 8.8-55.9 years); 12 patients (34.3%) were younger than 18 years at the time of procedure; 17 (48.6%) were patients with FVIII inhibitors. Among major procedures, orthopedic surgeries prevailed. All patients who underwent major procedures received factor replacement with either recombinant activated factor VII (patients with inhibitors) or FVIII (patients without inhibitors). Factor concentrates were administered prior to 32 (84.2%) of the minor procedures. Repeated doses were given according to international expert opinion recommendations and patients' condition.There were 7 bleeding events in 6 patients, 5 were major bleeds, including 1 patient who underwent a minor procedure without factor replacement. None of the patients experienced a thrombotic complication. Conclusion: Invasive procedures can be performed safely in patients receiving emicizumab prophylaxis with close surveillance after surgery. Factor concentrates may be advised in selected patients undergoing minor procedures.

3K3A-Activated Protein C Inhibits Choroidal Neovascularization Growth and Leakage and Reduces NLRP3 Inflammasome, IL-1ß, and Inflammatory Cell Accumulation in the Retina.

3K3A-Activated Protein C (APC) is a recombinant variant of the physiological anticoagulant APC with cytoprotective properties and reduced bleeding risks. We studied the potential use of 3K3A-APC as a multi-target therapeutic option for choroidal neovascularization (CNV), a common cause of vision loss in age-related macular degeneration. CNV was induced by laser photocoagulation in a murine model, and 3K3A-APC was intravitreally injected. The impact of 3K3A-APC treatment on myeloid and microglia cell activation and recruitment and on NLRP3 inflammasome, IL-1ß, and VEGF levels was assessed using cryosection, retinal flat-mount immunohistochemistry and vascular imaging. Additionally, we evaluated the use of fluorescein angiography as a surrogate marker for in vivo evaluation of the efficacy of 3K3A-APC treatment against leaking CNV lesions. Our results demonstrated that 3K3A-APC treatment significantly reduced the accumulation and activation of myeloid cells and microglia in the CNV area and decreased the NLRP3 and IL-1ß levels at the CNV site and the surrounding retina. Furthermore, 3K3A-APC treatment resulted in leakage regression and CNV growth suppression. These findings indicate that the anti-inflammatory activities of 3K3A-APC contribute to CNV inhibition. Our study suggests the potential use of 3K3A-APC as a novel multi-target treatment for CNV.

Activated Protein C (APC) and 3K3A-APC-Induced Regression of Choroidal Neovascularization (CNV) Is Accompanied by Vascular Endothelial Growth Factor (VEGF) Reduction.

The activated protein C (APC) ability to inhibit choroidal neovascularization (CNV) growth and leakage was recently shown in a murine model. A modified APC, 3K3A-APC, was designed to reduce anticoagulant activity while maintaining full cytoprotective properties, thus diminishing bleeding risk. We aimed to study the ability of 3K3A-APC to induce regression of CNV and evaluate vascular endothelial growth factor (VEGF) role in APC's activities in the retina. CNV was induced by laser photocoagulation on C57BL/6J mice. APC and 3K3A-APC were injected intravitreally after verification of CNV presence. CNV volume and vascular penetration were evaluated on retinal pigmented epithelium (RPE)-choroid flatmount by fluorescein isothiocyanate (FITC)-dextran imaging. VEGF levels were measured using immunofluorescence anti-VEGF staining. We found that 3K3A-APC induced regression of pre-existing CNV. VEGF levels, measured in the CNV lesion sites, significantly decreased upon APC and 3K3A-APC treatment. Reduction in VEGF was sustained 14 days post a single APC injection. As 3K3A-APC retained APCs' activities, we conclude that the anticoagulant properties of APC are not mandatory for APC activities in the retina and that VEGF reduction may contribute to the protective effects of APC and 3K3A-APC. Our results highlight the potential use of 3K3A-APC as a novel treatment for CNV and other ocular pathologies.

Single Low Dose of rFVIIa Combined with Antifibrinolytic Agent is a Simple and Safe Treatment for Factor XI-Deficient Patients undergoing Surgery.

BACKGROUND: Factor XI (FXI) deficiency is a rare autosomal bleeding disorder. The rarity of spontaneous bleeding and absence of optimal tools to predict the bleeding risk in FXI-deficient patients hamper the standardization of prophylactic treatment enabling them to undergo major surgeries without blood products. OBJECTIVES: We explored the effectiveness of a single and very low dose of recombinant factor VIIa (rFVIIa) along with tranexamic acid (TXA) as prophylactic treatment for FXI-deficient patients undergoing various types of surgery at various sites of injury. We studied the potential use of thrombin generation (TG) as a surrogate tool for predicting thrombogenicity. PATIENTS AND METHODS: Our cohort consisted of 10 patients with severe FXI deficiency undergoing 12 interventions. Patients received a single dose of 10 to 15 µg/kg rFVIIa at the end of surgery in addition to TXA initiated 2 hours before surgery at the dose of 4 g/day for 3 to 5 days. TG was tested before and 30 minutes after rFVIIa administration. RESULTS: All operations were uneventful and none of the patients bled excessively or required blood products. No thrombotic event was reported, and the postoperative hospitalization duration was comparable to that of patients without bleeding disorders. TG performed at the peak of rFVIIa was below the curve of healthy controls, thus confirming that the administered dose was not thrombogenic. CONCLUSION: A single very low dose of rFVIIa along with TXA is a simple and safe treatment to control hemostasis in severe FXI-deficient patients undergoing diverse type of surgical procedure at various sites.

Emicizumab prophylaxis among infants and toddlers with severe hemophilia A and inhibitors-a single-center cohort.

BACKGROUND: Emicizumab is a bispecific antibody that bridges factor IXa and factor X to restore hemostasis in patients with hemophilia A (HA). Its efficacy and safety have been proven in multicenter trials. However, real world data regarding its use in very young children are currently lacking. Ancillary test results for monitoring emicizumab's hemostatic effect and their clinical correlations are scarce. METHODS: Children with HA and inhibitors treated by emicizumab were prospectively followed at our center. Laboratory follow-up included rotational thromboelastometry (ROTEM) and thrombin generation (TG), prior to and during treatment. RESULTS: Eleven children whose median age was 26 months were treated by emicizumab and followed for a median of 36 weeks. During follow-up, none experienced hemarthrosis or any other spontaneous bleeds. For 7/11 patients, emicizumab prophylaxis was sufficient to maintain hemostasis without additional supplemental therapy. Only 4/11 patients were occasionally treated with recombinant activated FVII for trauma. Two minor surgeries were safely performed without supplemental therapy while another procedure was complicated by major bleeding. TG parameters improved for all patients, correlating with their clinical status. Interestingly, the lowest TG values were obtained for patients experiencing bleeding episodes, while ROTEM parameters in all patients were close to the normal range. CONCLUSIONS: This study confirms the safety and efficacy of emicizumab in reducing bleeds in young children with HA with inhibitors, including infants. However, surgeries warrant caution as emicizumab prophylaxis may not be sufficient for some procedures. TG may more accurately reflect the hemostasis state than ROTEM in pediatric patients treated with emicizumab.

Comparison of Subconjunctival Aflibercept and Betamethasone for the Treatment of Formed Corneal Neovascularization in a Rabbit Model.

AIM: To compare the efficacy of aflibercept (Eylea®), a potent antivascular endothelial growth factor (VEGF) agent, with betamethasone (Celestone®) and placebo for the treatment of formed corneal neovascularization in a rabbit model. METHODS: A central corneal chemical burn was created in the right eye of 24 New Zealand albino rabbits. Four weeks later, the rabbits were randomly divided into 4 equal groups for subconjunctival injection of aflibercept, betamethasone, aflibercept+ betamethasone, or saline (control). Digital photographs taken at weekly intervals were rated by 2 masked observers for extent, centricity, and density of corneal neovascularization according to a predefined scale. The percentage of corneal surface involved by neovascularization was quantified by image analysis software (Fiji-J). The change in corneal neovascularization from treatment administration (4 weeks after injury) to 4 weeks later (8 weeks after injury) was assessed. The rabbits were then euthanized, and their eyes were enucleated and processed for histopathological and immunofluorescence studies. RESULTS: There was no significant difference in the change in corneal neovascularization after treatment among the 4 groups according to the digital images (p > 0.15) or histological evaluation with hematoxylin and eosin (p > 0.08). On immunofluorescence assay, a lower VEGF concentration was observed in all treatment groups compared to the control group. CONCLUSIONS: In this rabbit model, corneal neovascularization induced by chemical burn failed to regress with treatment with aflibercept, betamethasone, or their combination.

Alternative treatment options for pediatric hemophilia B patients with high-responding inhibitors: A thrombin generation-guided study.

Little is known about the challenging treatment of pediatric patients with hemophilia B and inhibitors due to disease rarity. We describe three patients diagnosed in childhood and followed up to 9 years. All three had allergic reactions to Factor IX, but two were later safely treated for bleeding episodes with activated prothrombin complex concentrates (APCC = FEIBA). The third was given only recombinant activated Factor VIIa. Based on ex vivo thrombin generation analysis, a new alternative treatment of combined bypassing agents was administered for bleeding episodes and several minor surgical procedures with no treatment-associated adverse events or thrombosis.

From thrombasthenia to next generation thrombocytopenia: Neonatal alloimmune thrombocytopenia induced by maternal Glanzmann thrombasthenia.

BACKGROUND: Glanzmann thrombasthenia (GT) is a rare autosomal recessive disorder of platelet function caused by mutations in the genes coding for integrin αIIbß3. The aim of this study was to examine the outcome of newborns of GT mothers, with emphasis on thrombocytopenia and bleeding manifestations and their relation to maternal antiplatelet antibodies. PROCEDURE: Medical files of all female patients with GT treated in a single tertiary center from 1999 to 2017 were searched for details on pregnancy and birth. The medical files of their newborns were retrieved, and data on the postnatal course were collected. RESULTS: Nine babies were born to five patients with GT at our center during the study period. Three of the nine newborns had severe thrombocytopenia, and all three were offspring of GT mothers who were positive for antiplatelet antibodies. CONCLUSION: Pregnant GT patients should be examined for platelet antibodies. Assessment and management protocols (including treatment with intravenous immunoglobulins) for fetal and neonatal alloimmune thrombocytopenia should be considered.

A novel approach using ancillary tests to guide treatment of Glanzmann thrombasthenia patients undergoing surgical procedures.

BACKGROUND: Glanzmann thrombasthenia (GT) is a disorder of platelet function. Standard therapy includes platelet transfusions, which may be hampered by antiplatelet antibodies. AIMS: To assess potential correlation between bleeding and number of active platelets in GT patients undergoing surgery. Clinical peri- operative patients' hemostasis was compared with flow cytometry analysis (FC), and whole blood clot formation. METHODS: GT patients undergoing surgery were included. Blood counts, platelet activation studies, FC and rotational thromboelastography (ROTEM) were performed as ancillary tests to estimate the effectiveness of treatment. RESULTS: A total of 4 GT patients undergoing 5 surgeries were included. Consecutive FC analysis following platelet transfusions showed gradual decrease of donor platelets with a nadir of 3280 platelets in patients who experienced no post procedural bleeding following minor procedures. After major surgery, bleeding occurred when donor platelets decreased to 2600-4280. Decline in donor platelets was associated with reduced clot firmness as noted by ROTEM. CONCLUSION: Results suggest that very low number of active donor platelets may suffice to achieve proper hemostasis in certain procedures. Our study points to the potential role of consecutive FC examinations to demonstrate the number of donor platelets as an ancillary tool for decision making in GT patients undergoing surgery.

Treatment tailoring for factor V deficient patients and perioperative management using global hemostatic coagulation assays.

INTRODUCTION: Congenital factor V deficiency (FVD) is a rare bleeding disorder with an estimated incidence of 1 in 1000,000 in the general population. Since the common coagulation tests do not correlate with the bleeding tendency there is an unmet need to predict FVD patients' bleeding hazard prior to surgical interventions. AIM: To optimize treatment prior to surgical interventions, using global coagulation assays, thrombin generation (TG) and rotating thromboelastogram (ROTEM). METHODS: Our cohort included 5 patients with FVD, 4 severe and one mild. Two of them underwent TG and ROTEM prior to surgical interventions, including ex vivo spiking assays using bypass agents and platelets spiking. RESULTS: All five patients exhibited prolonged PT and PTT, non-dependent on their bleeding tendency. Patient 1, who demonstrated severe bleeding phenotype, underwent surgery treated by combination of APCC (FEIBA) and platelet transfusion. Therapy was guided by global tests (TG as well as ROTEM) results. During the pre and post-operative period neither excessive bleeding nor any thrombosis was noted. In contrast, TG and ROTEM analysis of patient 4 has lead us to perform the surgery without any blood products' support. Indeed, the patient did not encounter any bleeding. CONCLUSION: Global coagulation assays may be useful ancillary tools guiding treatment decisions in FVD patients undergoing surgical procedures.

Mobile Laser Indirect Ophthalmoscope: For the Induction of Choroidal Neovascularization in a Mouse Model.

PURPOSE: This study aims to evaluate and standardize the reliability of a mobile laser indirect ophthalmoscope in the induction of choroidal neovascularization (CNV) in a mouse model. MATERIALS & METHODS: A diode laser indirect ophthalmoscope was used to induce CNV in pigmented male C57BL/6J mice. Standardization of spot size and laser intensity was determined using different aspheric lenses with increasing laser intensities applied around the optic disc. Development of CNV was evaluated 1, 5, and 14 days post laser application using fluorescein angiography (FA), histology, and choroidal flat mounts stained for the endothelial marker CD31 and FITC-dextran. Correlation between the number of laser hits to the number and size of developed CNV lesions was determined using flat mount choroid staining. The ability of intravitreally injected anti-human and anti-mouse VEGF antibodies to inhibit CNV induced by the mobile laser was evaluated. RESULTS: Laser parameters were standardized on 350 mW for 100 msec, using the 90 diopter lens to accomplish the highest incidence of Bruch's membrane rupture. CNV lesions' formation was validated on days 5 and 14 post laser injury, though FA showed leakage on as early as day 1. The number of laser hits was significantly correlated with the CNV area. CNV growth was successfully inhibited by both anti-human and mouse VEGF antibodies. CONCLUSION: The mobile laser indirect ophthalmoscope can serve as a feasible and a reliable alternative method for the CNV induction in a mouse model.

Combination of hemostatic therapies for treatment of patients with hemophilia A and inhibitors.

BACKGROUND: Therapy application and monitoring of patients with hemophilia A (HA) and inhibitors are challenging. In the current study, combined FVIII - bypass therapy was implemented for a cohort of severe HA patients with inhibitors. METHODS: Plasma of 15 HA patients with inhibitors was spiked ex vivo with FVIII, rFVIIa, FEIBA and their combinations and thrombin generation (TG) was studied. Some patients who experienced hemarthroses or required minor surgeries were treated by a combined concomitant administration of FVIII+FEIBA as IV bolus doses. RESULTS: TG spiking studies showed individual responses not correlated to inhibitor titer. Combinations of agents augmented TG as compared to any single agent, while combined FVIII+FEIBA yielded the highest TG, supporting it as a potential treatment. Following emergent successful surgery of child treated by concomitant FVIII+FEIBA, a total of 396 episodes in 7/15 patients were treated with concomitant FVIII+FEIBA. Five patients were treated for bleeding episodes only, whereas 2 were children undergoing immune tolerance induction (ITI) with FEIBA prophylaxis. Four minor surgeries were performed on FVIII+FEIBA repeated infusions. Neither thrombosis nor any other adverse events were documented. CONCLUSION: A combination of FVIII+FEIBA may be effective and safe as an alternative treatment option for some high-responding inhibitor patients.

Correlation between Interleukin-6 and Thrombin-Antithrombin III Complex Levels in Retinal Diseases.

PURPOSE: This study aims to evaluate and correlate the levels of interleukin-6 (IL-6) and thrombin-antithrombin III complex (TAT) in the vitreous of patients with different vitreoretinal pathologies. METHODS: Vitreous samples were collected from 78 patients scheduled for pars plana vitrectomy at a tertiary medical center. Patients were divided by the underlying vitreoretinal pathophysiology, as follows: macular hole (MH)/epiretinal membrane (ERM) (n = 26); rhegmatogenous retinal detachment (RRD) (n = 32); and proliferative diabetic retinopathy (PDR) (n = 20). Levels of IL-6 and TAT were measured by enzyme-linked immunosorbent assay and compared among the groups. RESULTS: A significant difference was found in the vitreal IL-6 and TAT levels between the MH/ERM group and both the PDR and RRD groups (P < 0.001 for all). Diabetes was associated with higher IL-6 levels in the RRD group. Different relationships between the IL-6 and TAT levels were revealed in patients with different ocular pathologies. CONCLUSION: Our results imply that variations in vitreal TAT level may be attributable not only to an inflammatory reaction or blood-retinal barrier breakdown, but also to intraocular tissue-dependent regulation of thrombin.

Changes in Retinal Function and Cellular Remodeling Following Experimental Retinal Detachment in a Rabbit Model.

Purpose. To explore functional electroretinographic (ERG) changes and associated cellular remodeling following experimental retinal detachment in a rabbit model. Methods. Retinal detachment was created in ten rabbits by injecting 0.1 ml balanced salt solution under the retina. Fundus imaging was performed 0, 3, 7, 14, and 21 days postoperatively. ERGs were recorded pre- and 7 and 21 days postoperatively. Eyes were harvested on day 21 and evaluated immunohistochemically (IHC) for remodeling of second- and third-order neurons. Results. Retinal reattachment occurred within two weeks following surgery. No attenuation was observed in the photopic or scotopic a- and b-waves. A secondary wavefront on the descending slope of the scotopic b-wave was the only ERG result that was attenuated in detached retinas. IHC demonstrated anatomical changes in both ON and OFF bipolar cells. Bassoon staining was observed in the remodeled dendrites. Amacrine and horizontal cells did not alter, but Muller cells were clearly reactive with marked extension. Conclusion. Retinal detachment and reattachment were associated with functional and anatomical changes. Exploring the significance of the secondary scotopic wavefront and its association with the remodeling of 2nd- and 3rd-order neurons will shade more light on functional changes and recovery of the retina.

Thrombin generation as a predictor of thromboembolic events in multiple myeloma patients.

BACKGROUND: Multiple myeloma (MM) is characterized by an increased incidence of thromboembolic events, especially when immunomodulatory drugs are used. Currently, our ability to predict these thrombotic events is limited. We hypothesized that global coagulation tests may be predictive of thrombotic events in MM patients. METHODS: Blood samples were taken from 36 MM patients before and during routine treatment. Thrombin generation (TG) tests including endogenous thrombin potential (ETP) and peak height were analyzed. RESULTS: Patients were followed for a median of 2.5years. Those who developed thrombotic events were characterized by significantly higher ETP and peak height values compared to those who did not (P=0.001). In these patients, we identified a gradual increase in TG parameters that preceded the thrombotic event. Anticoagulation therapy was associated with a significant decrease in ETP and peak height values (P<0.001). There was no statistically significant difference in TG parameters between newly diagnosed MM patients and healthy subjects, as well as between MM patients prior to and during chemotherapy. CONCLUSIONS: TG tests might predict thrombotic events in MM patients. Thus, TG tests may be incorporated into decision-making protocols of prophylactic anticoagulant therapy in MM patients.

Effect of Histone Deacetylase Inhibitor, Butyroyloxymethyl-Diethyl Phosphate (AN-7), on Corneal Neovascularization in a Mouse Model.

PURPOSE: To examine whether butyroyloxymethyl-diethyl phosphate (AN-7), a histone deacetylase inhibitor, inhibits chemically induced corneal neovascularization (NV) in mice. METHODS: Corneal NV was induced in the right eye of male C57BL mice by application of a mixture of 75% silver nitrate and 25% potassium nitrate to the corneal center. Immediately thereafter, the mice were randomized into 2 groups, receiving an intraperitoneal injection of AN-7 or saline, which served as control. Corneal NV was evaluated at constant time intervals from the corneal injury by corneal photographs and the area of corneal NV was measured. Centricity and density of the corneal vascularization were graded. Corneal flat mounts blood vessels staining and histological studies were performed on day 10. Unpaired t-test was used for group comparisons. RESULTS: The corneal neovascular area was statistically significantly reduced by AN-7 treatment on days 10 and 14 postinjury and compared with the untreated group. The centricity and density of the corneal NV between treated and untreated groups showed no significant difference at any time point. CONCLUSIONS: Systemic treatment with AN-7 had a significant inhibitory effect on chemical burn-induced corneal NV in mice. These results suggest that AN-7 should be further evaluated for its therapeutic potential for the treatment of corneal NV.

Possible involvement of NETosis in inflammatory processes in the eye: Evidence from a small cohort of patients.

Purpose: To evaluate whether NETosis is involved in cytokine-induced ocular inflammation and to track neutrophil extracellular traps (NET) complexes in patients with proliferative diabetic retinopathy (PDR). Methods: For the animal model, the eyes of C57BL/6J mice were intravitreally injected with interleukin-8 (IL-8), tumor necrosis factor alpha (TNF-α), or saline. Histology and immunofluorescence staining for CD11b, neutrophil elastase (NE), myeloperoxidase (MPO), citrullinated histone 3 (H3Cit), and net-like structure were performed. Vitreous samples were collected from patients with PDR; the PDR1 group had no need for repeated surgical intervention, and the PDR2 group had repeated vitreous bleeding or other complication and controls. Levels of MPO, H3Cit-MPO, and NE-MPO complex were measured with enzyme-linked immunosorbent assay (ELISA). Results: Massive influx of CD11+ inflammatory cells, involving the anterior and posterior chambers, was observed in the murine eyes 24 h after the IL-8 or TNF-α injections. Cells excreted to their surroundings an extracellular net-like structure positive for NE, MPO, and H3Cit. H3Cit staining was abolished with the DNase I treatment, indicating the presence of extracellular DNA in the net-like structures. The vitreous samples of the patients with PDR2 contained statistically significantly higher levels of MPO (173±230) compared to those of the patients with PDR1 (12.0±33.0, p<0.05) or the controls (0.00, p<0.01). The levels of H3Cit-MPO and NE-MPO complexes were also statistically significantly higher in the patients with PDR2 (776.0±1274, 573.0±911.0, respectively) compared to those in the patients with PDR1 (0, p<0.05) and the controls (0, p<0.05). Conclusions: This study showed the existence of NETosis in cytokine-induced ocular inflammation in a mouse model and human samples. Furthermore, the extent of NET complex formation was higher in a subset of patients who exhibited more complicated PDR.

The small tellurium-based compound SAS suppresses inflammation in human retinal pigment epithelium.

PURPOSE: Pathological angiogenesis and chronic inflammation greatly contribute to the development of choroidal neovascularization (CNV) in chorioretinal diseases involving abnormal contact between retinal pigment epithelial (RPE) and endothelial cells (ECs), associated with Bruch's membrane rupture. We explored the ability of the small organotellurium compound octa-O-bis-(R,R)-tartarate ditellurane (SAS) to mitigate inflammatory processes in human RPE cells. METHODS: Cell adhesion assays and analyses of gene and protein expression were used to examine the effect of SAS on ARPE-19 cells or primary human RPE cells that were grown alone or in an RPE-EC co-culture. RESULTS: Adhesion assays showed that SAS inhibited αv integrins expressed on RPE cells. Co-cultures of RPE cells with ECs significantly reduced the gene expression of PEDF, as compared to RPE cells cultured alone. Both SAS and the anti-αvß3 antibody LM609 significantly enhanced the production of PEDF at both mRNA and protein levels in RPE cells. RPE cells co-cultured with EC exhibited increased gene expression of CXCL5, COX1, MMP2, IGF1, and IL8, all of which are involved in both angiogenesis and inflammation. The enhanced expression of these genes was greatly suppressed by SAS, but interestingly, remained unaffected by LM609. Zymography assay showed that SAS reduced the level of MMP-2 activity in RPE cells. We also found that SAS significantly suppressed IL-1ß-induced IL-6 expression and secretion from RPE cells by reducing the protein levels of phospho-IkappaBalpha (pIκBα). CONCLUSIONS: Our results suggest that SAS is a promising anti-inflammatory agent in RPE cells, and may be an effective therapeutic approach for controlling chorioretinal diseases.