E. Iliaki

Insulin-Like Growth Factor-I Plays a Pathogenetic Role in Diabetic Retinopathy

Diabetic retinopathy is a leading cause of blindness in the Western world. Aberrant intercellular adhesion molecule-1 expression and leukocyte adhesion have been implicated in its pathogenesis, raising the possibility of an underlying chronic inflammatory mechanism. In the current study, the role of insulin-like growth factor (IGF)-I in these processes was investigated. We found that systemic inhibition of IGF-I signaling with a receptor-neutralizing antibody, or with inhibitors of PI-3 kinase (PI-3K), c-Jun kinase (JNK), or Akt, suppressed retinal Akt, JNK, HIF-1alpha, nuclear factor (NF)-kappaB, and AP-1 activity, vascular endothelial growth factor (VEGF) expression, as well as intercellular adhesion molecule-1 levels, leukostasis, and blood-retinal barrier breakdown, in a relevant animal model. Intravitreous administration of IGF-I increased retinal Akt, JNK, HIF-1alpha, NF-kappaB, and AP-1 activity, and VEGF levels. IGF-I stimulated VEGF promoter activity in vitro, mainly via HIF-1alpha, and secondarily via NF-kappaB and AP-1. In conclusion, IGF-I participates in the pathophysiology of diabetic retinopathy by inducing retinal VEGF expression via PI-3K/Akt, HIF-1alpha, NF-kappaB, and secondarily, JNK/AP-1 activation. Taken together, these in vitro and in vivo signaling studies thus identify potential targets for pharmacological intervention to preserve vision in patients with diabetes.

Inhibition of Hsp90 attenuates inflammation in endotoxin-induced uveitis

Heat shock protein (Hsp) 90 inhibitors, such as 17‐allylamino‐17‐demethoxy‐geldanamycin (17‐AAG), constitute promising novel therapeutic agents. We investigated the anti‐inflammatory activity of 17‐AAG in endotoxin‐induced uveitis (EIU) in rats. After the induction of EIU with a footpad injection of lipopolysaccharide (LPS), female Lewis rats received a single intraperitoneal. (i.p.) injection of 17‐AAG or vehicle. Twenty‐four hours later, the retinas were extracted and assayed for leukocyte adhesion; blood‐retinal barrier breakdown;VEGF, TNF‐α, IL‐1β, and CD14 protein levels;NF‐κB and HIF‐1α activity;hsp90 and 70 levels and expression and phosphorylation of the tight junction proteins ZO‐1 and occludin. 17‐AAG treatment significantly suppressed the LPS‐induced increase in retinal leukocyte adhesion;vascular leakage; NF‐KB, HIF‐1α, p38, and PI‐3K activity;and VEGF, TNF‐α, and IL‐1β levels. 17‐AAG also suppressed phos‐phorylation of ZO‐1 and occludin by inhibiting their association with p38 and PI‐3K Although 17‐AAG treatment did not reduce the LPS‐induced increase in total CD14 levels in leukocytes, it significantly decreased membrane CD14 levels. These data suggest that Hsp90 inhibition suppresses several cardinal manifestations of endotoxin‐induced uveitis in the rat. 17‐AAG has demonstrated a favorable safety profile in clinical trials in cancer patients and represents a promising therapeutic agent for the treatment of inflammatory eye diseases.–Poulaki V., Iliaki, E., Mitsiades, N., Mitsiades, C. S., Paulus, Y. M., Bula, D. V., Gragoudas, E. S., Miller J. W. Inhibition of Hsp90 attenuates inflammation in endotoxin‐induced uveitis. FASEB J. 21, 2113–2123 (2007)

Activin A in the Regulation of Corneal Neovascularization and Vascular Endothelial Growth Factor Expression

Activin A, a dimeric glycoprotein that belongs to the transforming growth factor-beta superfamily, governs cellular differentiation in a wide variety of models and has been implicated in the regulation of angiogenesis. We examined the role of activin A and its downstream signaling pathway in a murine model of inflammatory corneal neovascularization induced by mechanical injury (debridement), and in vitro in corneal epithelial cells. Activin A expression increased steadily from day 2 until day 8 after mechanical debridement in vivo, paralleling vascular endothelial growth factor (VEGF) expression. Administration of recombinant activin A in mice increased the area of neovascularization, VEGF expression, and the kinase activities of p38 and p42/44 MAPKs after mechanical debridement. Systemic inhibition of activin A in vivo with a neutralizing antibody reduced the area of neovascularization, VEGF expression, and p38 and p42/44 MAPK activity, whereas administration of an isotype-matched control antibody had no effect. In vitro treatment with activin A increased VEGF secretion, as well as p38 and p42/44 MAPK activity in corneal epithelial cells, whereas concurrent administration of specific inhibitors of p38 or p42/44 MAPK abolished the stimulatory effect of activin A on VEGF production. We conclude that activin A stimulates inflammatory corneal angiogenesis by increasing VEGF levels through a p38 and p42/44 MAPK-dependent mechanism.

Role of α4 Integrin (CD49d) in the Pathogenesis of Diabetic Retinopathy

PURPOSE The pathophysiology of diabetic retinopathy is mediated by leukocyte adhesion to the vascular endothelium of the diabetic retina, which results in endothelial injury, blood-retina barrier breakdown, and capillary nonperfusion. Leukocyte adhesion is triggered by the interaction of vascular endothelium adhesion molecules, such as ICAM-1, with leukocyte integrins, such as CD18. Inhibition of ICAM-1/CD18 signaling suppresses but does not completely abolish the cardinal manifestations of diabetic retinopathy, suggesting a role for additional adhesion molecules. Integrin alpha 4 (CD49d), in complex with integrin beta1, forms very late antigen-4 (VLA-4), which interacts with vascular cell adhesion molecule-1. The authors have now studied the role of integrin alpha 4/CD49d in the pathogenesis of diabetic retinopathy. METHODS Diabetes mellitus was induced in Long Evans rats with streptozotocin, and an anti-alpha 4 integrin/CD49d neutralizing antibody was injected 5 and 10 days later. Two weeks after streptozotocin administration, vascular leakage was quantified with the Evans Blue technique. Leukostasis was measured with a static adhesion assay ex vivo and the FITC-lectin perfusion method in vivo. Retinal VEGF and TNF-alpha levels and NF-kappaB activity were measured by ELISA. RESULTS Blockade of alpha 4 integrin/CD49d attenuated the diabetes-induced upregulation of NF-kappaB activation, VEGF, and TNF-alpha protein levels and reduced significantly diabetes-induced leukocyte adhesion and vascular leakage. CONCLUSIONS These data identify alpha 4 integrin/CD49d as a mediator of leukocyte adhesion and the resultant early signature abnormalities of diabetic retinopathy. Inhibition of this signaling pathway may hold promise for clinical activity in patients with diabetes.

VLA-4 blockade suppresses endotoxin-induced uveitis: in vivo evidence for functional integrin up-regulation

Leukocyte adhesion to the vascular wall is a critical early step in the pathogenesis of inflammatory diseases and is mediated in part by the leukocyte integrin, VLA‐4, which binds to endothelial vascular cell adhesion molecule (VCAM) −1. Here, we investigate VLA‐4s role in endotoxin‐induced uveitis (EIU). At various time points (6–48 h) after EIU induction, the severity of the inflammation was evaluated by quantifying cell and protein content in the aqueous fluid, firm leukocyte adhesion in the retinal vessels, and the number of extravasated leukocytes into the vitreous. Functional activation of VLA‐4 in vivo was investigated in our previously introduced autoperfused micro flow chamber assay. Firm adhesion of EIU leukocytes to immobilized VCAM‐1 under physiological blood flow conditions was significantly increased compared with normal controls (P<0.05), suggesting an important role for VLA‐4 in EIU. VLA‐4 blockade in vivo significantly suppressed all uveitis‐related inflammatory parameters studied, decreasing the clinical score by 45% (P<0.01), protein content in the aqueous fluid by 21% (P<0.01), retinal leukostasis by 68% (P<0.01), and leukocyte accumulation in the vitreous by 75% (P<0.01). Our data provide novel evidence for functional up‐regulation of VLA‐4 during EIU and suggest VLA‐4 blockade as a promising therapeutic strategy for treatment of acute inflammatory eye diseases.—Hafezi‐Moghadam, A., Noda, K., Almulki, L., Iliaki, E. F., Poulaki, V., Thomas, K. L., Nakazawa, T., Hisatomi, T., Miller, J. W., Gragoudas, E. S. VLA‐4 blockade suppresses endotoxin‐induced uveitis: in vivo evidence for functional integrin up‐regulation. FASEB J. 21, 464–474 (2006)

Travel to Brazil: analysis of data from the Boston Area Travel Medicine Network (BATMN) and relevance to travelers attending world cup and olympics.

We describe travelers who were evaluated pre-travel to Brazil from March 2008 through July 2010 in the Boston area. Of 599 Brazil travelers, 71%, 58%, and 50% received vaccines for yellow fever (YF), typhoid, and hepatitis A, respectively. Fewer received influenza and hepatitis B vaccines (14%, 11%). A total of 60% traveled during Brazils peak influenza season, and one fourth visited during peak dengue transmission. The 2014 World Cup and 2016 Olympics include events throughout Brazil. Travelers should seek pre-travel assessment including YF and malaria risk; travelers should be vaccinated against influenza, be up to date on other routine vaccines, and be prepared to protect themselves against mosquitoes.

A Curious Case of Lactobacillus casei in a Prosthetic Joint:: Was It the Yogurt?

1. Golub JS, Chen PH, Otto KJ et al. Prevalence of perceived dysphonia in a geriatric population. J Am Geriatr Soc 2006;54:1736–1739. 2. Schneider S, Plank C, Eysholdt U et al. Voice function and voice-related quality of life in the elderly. Gerontology 2011;57:109–114. 3. Hirano M, Kurita S, Nakashima T. Growth, development, and aging of human vocal folds. In: Bless D, Abbs JH, eds. Vocal Fold Physiology. San Diego, CA: College Hill Press, 1983, pp 22–43. 4. Honjo I, Isshiki N. Laryngoscopic and voice characteristics of aged persons. Arch Otolaryngol 1980;106:149–150. 5. McMullen CA, Andrade FH. Functional and morphological evidence of age-related denervation in rat laryngeal muscles. J Gerontol A Biol Sci Med Sci 2009;64A:435–442. 6. Baken RJ. The aged voice: A new hypothesis. J Voice 2005;19:317–325. 7. Bloch I, Behrman A. Quantitative analysis of videostroboscopic images in presbylarynges. Laryngoscope 2001;111(11 Pt 1):2022–2027. 8. Linville SE. Source characteristics of aged voice assessed from long-term average spectra. J Voice 2002;16:472–479. 9. Burkhead LM, Sapienza CM, Rosenbek JC. Strength-training exercise in dysphagia rehabilitation: Principles, procedures, and directions for future research. Dysphagia 2007;22:251–265. 10. Thomas LB, Harrison AL, Stemple JC. Aging thyroarytenoid and limb skeletal muscle: Lessons in contrast. J Voice 2008;22:430–450.