[Shaken-baby syndrome and unilateral retinal hemorrhage?] / Shaken-Baby-Syndrom bei unilateraler retinaler Hämorrhagie?

Unilateral retinal hemorrhage in infants can be caused by vitamin K deficiency. The case described here with fatal outcome presents the medical history of a 2-month-old infant with vitamin K deficiency bleeding caused by the refusal of vitamin K prophylaxis by the parents. Ocular signs were unilateral intraretinal hemorrhage with Roth spots and preretinal hemorrhage over the complete back of the eye. The case demonstrates the importance of vitamin K prophylaxis for newborns.

In situ regeneration of retinal pigment epithelium by gene transfer of E2F2: a potential strategy for treatment of macular degenerations.

The retinal pigment epithelium (RPE) interacts closely with photoreceptors to maintain visual function. In degenerative diseases such as Stargardt disease and age-related macular degeneration, the leading cause of blindness in the developed world, RPE cell loss is followed by photoreceptor cell death. RPE cells can proliferate under certain conditions, suggesting an intrinsic regenerative potential, but so far this has not been utilised therapeutically. Here, we used E2F2 to induce RPE cell replication and thereby regeneration. In both young and old (2 and 18 month) wildtype mice, subretinal injection of non-integrating lentiviral vector expressing E2F2 resulted in 47% of examined RPE cells becoming BrdU positive. E2F2 induced an increase in RPE cell density of 17% compared with control vector-treated and 14% compared with untreated eyes. We also tested this approach in an inducible transgenic mouse model of RPE loss, generated through activation of diphtheria toxin-A gene. E2F2 expression resulted in a 10-fold increase in BrdU uptake and a 34% increase in central RPE cell density. Although in mice this localised rescue is insufficiently large to be demonstrable by electroretinography, a measure of massed retinal function, these results provide proof-of-concept for a strategy to induce in situ regeneration of RPE for the treatment of RPE degeneration.

Experimental gene transfer to the corneal endothelium.

Transfer of cDNA to corneal endothelial cells has been demonstrated in cell monolayers in vitro, in endothelium of whole thickness corneas ex vivo and following intracameral injection. Studies examining the feasibility and optimal methods for gene transfer to the cornea have used viral and non-viral vectors, initially histochemical or fluorescent marker genes, and in endothelium of numerous species ranging from mouse to man. As the feasibility of genetic modification of corneal endothelial cells has been successfully demonstrated in a number of cell culture and animal models, there is significant potential for gene transfer in the treatment of human corneal endothelial disease. The two most widely studied applications of gene transfer to endothelium are (i) transduction of immunomodulatory genes to donor corneal endothelium prior to transplantation as a strategy to delay allogeneic rejection and (ii) modulation of apoptosis or induction of replication in human corneal endothelial cells to increase cell density. Although continued improvements in vectors for gene transfer will improve the efficacy and safety of gene therapy, more detailed understanding of the altered biology of endothelium in disease will be necessary to allow selection of appropriate targets for a gene-based treatment approach.

[Corneal riboflavin/UV-A collagen cross-linking (CXL) in keratoconus: two-year results]. / Kollagenvernetzung mittels Riboflavin und UV-A-Strahlung (CXL) bei Keratokonus: Zwei-Jahres-Ergebnisse.

BACKGROUND: Photochemical collagen cross-linking with riboflavin and UV-A radiation (CXL) is reported to strengthen the cornea in keratoconus. This retrospective longitudinal study analyses the outcomes 2 years after CXL. METHODS: 46 eyes of 45 patients with keratoconus stadium 1 to 3 with disease progression confirmed by topography or patient history underwent CXL after corneal abrasion. Follow-up over 2 years included biomicroscopy, visual acuity, topography, pachymetry, and endothelial cell count. Changes were analysed with paired Student's t test or Wilcoxon signed-rank test. RESULTS: All patients showed initial haze (maximum 2 + ) and increase of epithelial surface irregularity resulting in temporarily reduced vision, but this resolved within 3 months. Medium visual acuity (logMAR) improved from 0.29 to 0.20 (p = 0.019, 12 months postop) or to 0.24 (p = 0.200; 24 months postop). This corresponds to an improvement (≧ 1 line) in 51 % of eyes, a loss of vision in 27 %. Mean maximum radius of curvature was reduced by 1.24 diopters (D) (95 % confidence interval 0.05 - 2.43; p = 0.042) in the first year, and reduced by 1.23 D (0.42 - 2.05; p = 0.004) at 2 years after CXL. Mean pachymetry showed a significant reduction of 23 µm (p = 0.0004, 1 year postop), endothelial cell count showed no significant change. CONCLUSION: In spite of a temporary reduction in vision, long-term outcome showed recovery or increase in visual acuity in the majority of eyes. Topography data indicate a stabilisation of keratoconus after CXL.

[Intraepithelial phototherapeutic keratectomy and alcohol delamination for recurrent corneal erosions--two minimally invasive surgical alternatives]. / Intraepitheliale Phototherapeutische Keratektomie und Alkohol-Abrasio zur Therapie der rezidivierenden Erosio corneae - zwei minimalinvasive chirurgische Alternativen.

BACKGROUND: Phototherapeutic keratectomy (PTK) has become established as a successful therapy for recurrent corneal erosions. After epithelial debridement, Bowman's lamella and anterior stroma are ablated by the Excimer laser. We have evaluated two alternative stroma-sparing treatment options, intraepithelial PTK, and alcohol delamination. PATIENTS AND METHODS: All treatments were performed in the relapse-free period. 17 eyes with recurrent corneal erosions were treated with intraepithelial PTK: from the intact epithelium, 12 - 25 microm of tissue were ablated by the Excimer laser (group I). Alcohol delamination was performed in 13 eyes (group II). Follow-up time was between 6 months and 7 years (mean 4.2 years). RESULTS: Both methods turned out to be safe, no refractive changes were detectable. After intraepithelial PTK, we saw a cumulative recurrence rate of 12 % after 1 year, 18 % after 2 years, and 24 % after 3 years, and a temporary subepithelial scaring was seen. Alcohol delamination resulted in a recurrence rate of 15 % during the whole follow-up time (no statistically significant difference compared to intraepithelial PTK), showing no haze or scarring. CONCLUSION: Both minimally invasive, stroma-sparing methods were effective for the treatment of trauma-associated recurrent erosion. The ablation of Bowman's lamella or anterior stroma does not seem to be necessary. However, for basal membrane dystrophy, we recommend PTK after epithelial debridement for the partial ablation of Bowman's lamella.

Yersinia enterocolitica invasin protein triggers differential production of interleukin-1, interleukin-8, monocyte chemoattractant protein 1, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor alpha in epithelial cells: implications for understanding the early cytokine network in Yersinia infections.

Yersinia enterocolitica infection of epithelial cells results in interleukin-8 (IL-8) mRNA expression. Herein we demonstrate that besides IL-8, increased mRNA levels of five other cytokines, IL-1alpha, IL-1beta, monocyte chemoattractant protein 1 (MCP-1), granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor alpha (TNF-alpha), can be detected upon infection of HeLa cells with Yersinia. Yersinia-triggered cytokine production was not affected by blocking phosphatidylinositol-3-phosphate kinase with wortmannin, which inhibited bacterial invasion. Comparable cytokine mRNA responses were triggered by Escherichia coli expressing Yersinia inv, while no response was triggered by an inv-deficient Yersinia mutant. Moreover, cytokine responses were independent from metabolic activity of the bacteria, as killed bacterial cells were sufficient for triggering cytokine responses in HeLa cells. Semiquantitative reverse transcription-PCR analysis was used to assess the kinetics of cytokine mRNA expression in infected HeLa cells. IL-8, IL-1alpha, IL-1beta, MCP-1, GM-CSF, and TNF-alpha mRNA expression increased within 1 h postinfection, reached a maximum after 3 to 4 h, and then declined to preinfection levels within 3 h. IL-8, MCP-1, and GM-CSF were secreted by HeLa cells, whereas IL-1alpha and IL-1beta were not secreted and thus were found exclusively intracellularly. TNF-alpha protein could not be detected in cell lysates or supernatants. Stimulation of HeLa cells with IL-1alpha was followed by increased IL-8 mRNA expression, whereas stimulation with IL-8 did not induce cytokine production. Likewise, MCP-1 and GM-CSF did not induce significant cytokine responses in HeLa cells. Our results implicate that the initial host response to Yersinia infection might be sustained by IL-8, MCP-1, and GM-CSF produced by epithelial cells.

Wortmannin blocks Yersinia invasin-triggered internalization, but not interleukin-8 production by epithelial cells.

In response to bacterial infection epithelial cells up-regulate expression and secretion of proinflammatory cytokines. Previous work from our laboratory showed that basolateral infection of polarized T84 cells with Yersinia enterocolitica induces interleukin-8 (IL-8) secretion in the absence of significant invasion. Here we studied Y. enterocolitica-induced IL-8 secretion by epithelial HeLa cells as a function of Yersinia invasion or adhesion. For this purpose we tried to separated induction of IL-8 secretion from invasion by treating HeLa cells with signal transduction inhibitors prior to infection. While staurosporin and genistein inhibited both Yersinia invasion and Yersinia-triggered IL-8 secretion, wortmannin, an inhibitor of the phosphatidylinositol-3-phosphate kinase (PI3-K), blocked invasion of Y. enterocolitica into HeLa cells but did not show any effect on IL-8 secretion. These results suggest that Yersinia adhesion might be sufficient to induce IL-8 secretion by epithelial cells. Further analysis demonstrated the requirement of the Yersinia invasion locus inv for adhesion-mediated induction of IL-8 secretion. Thus, HeLa cells infected with an E. coli strain expressing the Y. enterocolitica inv locus induced IL-8 secretion in the presence and absence of wortmannin. Reverse transcription-polymerase chain reaction analysis revealed that adhesion of inv-expressing Y. enterocolitica or E. coli results in the transcriptional activation of the IL-8 gene. These results suggest that Y. enterocolitica adhesion to host cells via Inv activates de novo synthesis and secretion of IL-8.