Transscleral Optical Phase Imaging of the Human Retina.

In-vivo observation of the human retina at the cellular level is crucial to detect the first signs of retinal diseases and properly treat them. Despite the phenomenal advances in adaptive optics (AO) systems, clinical imaging of many retinal cells is still elusive due to the low signal-to-noise ratio induced by transpupillary illumination. We present a transscleral optical phase imaging (TOPI) method, which relies on high-angle oblique illumination of the retina, combined with AO, to enhance cell contrast. Examination of eleven healthy volunteer eyes, without pupil dilation, shows the ability of this method to produce in-vivo images of retinal cells, from the retinal pigment epithelium to the nerve fibre layer. This method also allows the generation of high-resolution label-free ex-vivo phase images of flat-mounted retinas. The 4.4°x 4.4° field-of-view in-vivo images are recorded in less than 10 seconds, opening new avenues in the exploration of healthy and diseased retinas

Retrospective analysis of the quality of reports by author-suggested and non-author-suggested reviewers in journals operating on open or single-blind peer review models.

OBJECTIVES: To assess whether reports from reviewers recommended by authors show a bias in quality and recommendation for editorial decision, compared with reviewers suggested by other parties, and whether reviewer reports for journals operating on open or single-blind peer review models differ with regard to report quality and reviewer recommendations. DESIGN: Retrospective analysis of the quality of reviewer reports using an established Review Quality Instrument, and analysis of reviewer recommendations and author satisfaction surveys. SETTING: BioMed Central biology and medical journals. BMC Infectious Diseases and BMC Microbiology are similar in size, rejection rates, impact factors and editorial processes, but the former uses open peer review while the latter uses single-blind peer review. The Journal of Inflammation has operated under both peer review models. SAMPLE: Two hundred reviewer reports submitted to BMC Infectious Diseases, 200 reviewer reports submitted to BMC Microbiology and 400 reviewer reports submitted to the Journal of Inflammation. RESULTS: For each journal, author-suggested reviewers provided reports of comparable quality to non-author-suggested reviewers, but were significantly more likely to recommend acceptance, irrespective of the peer review model (p<0.0001 for BMC Infectious Diseases, BMC Microbiology and the Journal of Inflammation). For BMC Infectious Diseases, the overall quality of reviewer reports measured by the Review Quality Instrument was 5% higher than for BMC Microbiology (p=0.042). For the Journal of Inflammation, the quality of reports was the same irrespective of the peer review model used. CONCLUSIONS: Reviewers suggested by authors provide reports of comparable quality to non-author-suggested reviewers, but are significantly more likely to recommend acceptance. Open peer review reports for BMC Infectious Diseases were of higher quality than single-blind reports for BMC Microbiology. There was no difference in quality of peer review in the Journal of Inflammation under open peer review compared with single blind

Conspiracy in bacterial genomes

The rank ordered distribution of the codon usage frequencies for 123 bacteriae is best fitted by a three parameters function that is the sum of a constant, an exponential and a linear term in the rank n. The parameters depend (two parabolically) from the total GC content. The rank ordered distribution of the amino acids is fitted by a straight line. The Shannon entropy computed over all the codons is well fitted by a parabola in the GC content, while the partial entropies computed over subsets of the codons show peculiar different behavior, exhibiting therefore a first conspiracy effect. Moreover the sum of the codon usage frequencies over particular sets, e.g. with C and A (respectively G and U) as i-th nucleotide, shows a clear linear dependence from the GC content, exhibiting another conspiracy effect.Comment: revised version: introduction and conclusion enhanced, references added, figures added, some tables remove

Multimodal Highlighting of Structural Abnormalities in Diabetic Rat and Human Corneas.

PURPOSE: This study aimed to highlight structural corneal changes in a model of type 2 diabetes, using in vivo corneal confocal microscopy (CCM). The abnormalities were also characterized by transmission electron microscopy (TEM) and second harmonic generation (SHG) microscopy in rat and human corneas. METHODS: Goto-Kakizaki (GK) rats were observed at age 12 weeks (n = 3) and 1 year (n = 6), and compared to age-matched controls. After in vivo CCM examination, TEM and SHG microscopy were used to characterize the ultrastructure and the three-dimensional organization of the abnormalities. Human corneas from diabetic (n = 3) and nondiabetic (n = 3) patients were also included in the study. RESULTS: In the basal epithelium of GK rats, CCM revealed focal hyper-reflective areas, and histology showed proliferative cells with irregular basement membrane. In the anterior stroma, extracellular matrix modifications were detected by CCM and confirmed in histology. In the Descemet's membrane periphery of all the diabetic corneas, hyper-reflective deposits were highlighted using CCM and characterized as long-spacing collagen fibrils by TEM. SHG microscopy revealed these deposits with high contrast, allowing specific detection in diabetic human and rat corneas without preparation and characterization of their three-dimensional organization. CONCLUSION: Pathologic findings were observed early in the development of diabetes in GK rats. Similar abnormalities have been found in corneas from diabetic patients. TRANSLATIONAL RELEVANCE: This multidisciplinary study highlights diabetes-induced corneal abnormalities in an animal model, but also in diabetic donors. This could constitute a potential early marker for diagnosis of hyperglycemia-induced tissue changes

Nephropathy in Pparg-null mice highlights PPARγ systemic activities in metabolism and in the immune system.

Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-dependent transcription factor involved in many aspects of metabolism, immune response, and development. Total-body deletion of the two Pparg alleles provoked generalized lipoatrophy along with severe type 2 diabetes. Herein, we explore the appearance and development of structural and functional alterations of the kidney, comparing Pparg null-mice to their littermate controls (carrying Pparg floxed alleles). We show that renal hypertrophy and functional alterations with increased glucosuria and albuminuria are already present in 3 weeks-old Pparg null-mice. Renal insufficiency with decreased creatinine clearance progress at 7 weeks of age, with the advance of the type 2 diabetes. At 52 weeks of age, these alterations are accompanied by signs of fibrosis and mesangial expansion. More intriguingly, aged Pparg null-mice concomitantly present an anti-phospholipid syndrome (APS), characterized by the late appearance of microthrombi and a mesangioproliferative pattern of glomerular injury, associated with significant plasmatic levels of anti-β2- glycoprotein1 antibodies and renal deposition of IgG, IgM, and C3. Thus, in line with the role of PPARγ in metabolic homeostasis, Pparg null-mice first represent a potent model for studying the initiation and the development of diabetic nephropathy. Second, and in relation with the important PPARγ activity in inflammation and in immune system, these mice also highlight a new role for PPARγ signaling in the promotion of APS, a syndrome whose pathogenesis is poorly known and whose current treatment is limited to prevention of thrombosis events

Subconjunctival Injection of XG-102, a c-Jun N-Terminal Kinase Inhibitor Peptide, in the Treatment of Endotoxin-Induced Uveitis in Rats.

Abstract Purpose: XG-102, a TAT-coupled dextrogyre peptide inhibiting the c-Jun N-terminal kinase, was shown efficient in the treatment of experimental uveitis. Preclinical studies are now performed to determine optimal XG-102 dose and route of administration in endotoxin-induced uveitis (EIU) in rats with the purpose of clinical study design. METHODS: EIU was induced in Lewis rats by lipopolysaccharides (LPS) injection. XG-102 was administered at the time of LPS challenge by intravenous (IV; 3.2, 35 or 355 μg/injection), intravitreal (IVT; 0.08, 0.2 or 2.2 μg/eye), or subconjunctival (SCJ; 0.2, 1.8 or 22 μg/eye) routes. Controls received either the vehicle (saline) or dexamethasone phosphate injections. Efficacy was assessed by clinical scoring, infiltrating cells count, and expression of inflammatory mediators [inducible nitric oxide synthase (iNOS), cytokine-induced neutrophil chemoattractant-1 (CINC-1)]. The effect of XG-102 on phosphorylation of c-Jun was evaluated by Western blot. RESULTS: XG-102 demonstrated a dose-dependent anti-inflammatory effect in EIU after IV and SCJ administrations. Respective doses of 35 and 1.8 μg were efficient as compared with the vehicle-injected controls, but only the highest doses, respectively 355 and 22 μg, were as efficient as dexamethasone phosphate. After IVT injections, the anti-inflammatory effect of XG-102 was clinically evaluated similar to the corticoid's effect with all the tested doses. Regardless of the administration route, the lowest efficient doses of XG-102 significantly decreased the ration of phospho c-Jun/total c-Jun, reduced cells infiltration in the treated eyes, and significantly downregulated iNOS and CINC-1 expression in the retina. CONCLUSION: These results confirm that XG-102 peptide has potential for treating intraocular inflammation. SCJ injection appears as a good compromise to provide a therapeutic effect while limiting side effects

Poly-Gamma-Glutamic Acid (γ-PGA)-based encapsulation of Adenovirus to evade neutralizing antibodies.

In recent years, there has been an increasing interest in oncolytic adenoviral vectors as an alternative anticancer therapy. The induction of an immune response can be considered as a major limitation of this kind of application. Significant research efforts have been focused on the development of biodegradable polymer poly-gamma-glutamic acid (γ-PGA)-based nanoparticles used as a vector for effective and safe anticancer therapy, owing to their controlled and sustained-release properties, low toxicity, as well as biocompatibility with tissue and cells. This study aimed to introduce a specific destructive and antibody blind polymer-coated viral vector into cancer cells using γ-PGA and chitosan (CH). Adenovirus was successfully encapsulated into the biopolymer particles with an encapsulation efficiency of 92% and particle size of 485 nm using the ionic gelation method. Therapeutic agents or nanoparticles (NPs) that carry therapeutics can be directed specifically to cancerous cells by decorating their surfaces using targeting ligands. Moreover, in vitro neutralizing antibody response against viral capsid proteins can be somewhat reduced by encapsulating adenovirus into γ-PGA-CH NPs, as only 3.1% of the encapsulated adenovirus was detected by anti-adenovirus antibodies in the presented work compared to naked adenoviruses. The results obtained and the unique characteristics of the polymer established in this research could provide a reference for the coating and controlled release of viral vectors used in anticancer therapy.This work was funded by the Ministry of Higher Education and Scientific Research (Iraq). This work was also partially funded by the Research Investment Fund, University of Wolverhampton (Wolverhampton, United Kingdom) and the Italian Ministry of University and Research (MIUR)

In Vivo Retinal Pigment Epithelium Imaging using Transscleral Optical Imaging in Healthy Eyes.

To image healthy retinal pigment epithelial (RPE) cells in vivo using Transscleral OPtical Imaging (TOPI) and to analyze statistics of RPE cell features as a function of age, axial length (AL), and eccentricity. Single-center, exploratory, prospective, and descriptive clinical study. Forty-nine eyes (AL: 24.03 ± 0.93 mm; range: 21.9-26.7 mm) from 29 participants aged 21 to 70 years (37.1 ± 13.3 years; 19 men, 10 women). Retinal images, including fundus photography and spectral-domain OCT, AL, and refractive error measurements were collected at baseline. For each eye, 6 high-resolution RPE images were acquired using TOPI at different locations, one of them being imaged 5 times to evaluate the repeatability of the method. Follow-up ophthalmic examination was repeated 1 to 3 weeks after TOPI to assess safety. Retinal pigment epithelial images were analyzed with a custom automated software to extract cell parameters. Statistical analysis of the selected high-contrast images included calculation of coefficient of variation (CoV) for each feature at each repetition and Spearman and Mann-Whitney tests to investigate the relationship between cell features and eye and subject characteristics. Retinal pigment epithelial cell features: density, area, center-to-center spacing, number of neighbors, circularity, elongation, solidity, and border distance CoV. Macular RPE cell features were extracted from TOPI images at an eccentricity of 1.6° to 16.3° from the fovea. For each feature, the mean CoV was &lt; 4%. Spearman test showed correlation within RPE cell features. In the perifovea, the region in which images were selected for all participants, longer AL significantly correlated with decreased RPE cell density (R Spearman, Rs = -0.746; P &lt; 0.0001) and increased cell area (Rs = 0.668; P &lt; 0.0001), without morphologic changes. Aging was also significantly correlated with decreased RPE density (Rs = -0.391; P = 0.036) and increased cell area (Rs = 0.454; P = 0.013). Lower circular, less symmetric, more elongated, and larger cells were observed in those &gt; 50 years. The TOPI technology imaged RPE cells in vivo with a repeatability of &lt; 4% for the CoV and was used to analyze the influence of physiologic factors on RPE cell morphometry in the perifovea of healthy volunteers. Proprietary or commercial disclosure may be found after the references

Anti-Inflammatory Effect of Dexamethasone Controlled Released From Anterior Suprachoroidal Polyurethane Implants on Endotoxin-Induced Uveitis in Rats.

Targeted drug delivery to the ocular tissues remains a challenge. Biodegradable intraocular implants allow prolonged controlled release of drugs directly into the eye. In this study, we evaluated an anterior suprachoroidal polyurethane implant containing dexamethasone polyurethane dispersions (DX-PUD) as a drug delivery system in the rat model of endotoxin-induced uveitis (EIU). In vitro drug release was studied using PUD implants containing 8%, 20%, and 30% (wt/wt) DX. Cytotoxicity of the degradation products of DX-PUD was assessed on human ARPE-19 cells using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) test. Short-term ocular biocompatibility of suprachoroidal DX-PUD implants was evaluated in normal rat eyes. Endotoxin-induced uveitis was then induced in rat eyes preimplanted with DX-PUD. Clinical examination was performed at 24 hours; eyes were used to assess inflammatory cell infiltration and macrophage/microglial activation. Cytokine and chemokine expression in the iris/ciliary body and in the retina was investigated using quantitative PCR. Feasibility of anterior suprachoroidal PUD implantation was also tested using postmortem human eyes. A burst release was followed by a sustained controlled release of DX from PUD implants. By-products of the DX-PUD were not toxic to human ARPE-19 cells or to rat ocular tissues. Dexamethasone-PUD implants prevented EIU in rat eyes, reducing inflammatory cell infiltration and inhibiting macrophage/microglial activation. Dexamethasone-PUD downregulated proinflammatory cytokines/chemokines (IL-1β, IL-6, cytokine-induced neutrophil chemoattractant [CINC]) and inducible nitric oxide synthase (iNOS) and upregulated IL-10 anti-inflammatory cytokine. Polyurethane dispersion was successfully implanted into postmortem human eyes. Dexamethasone-PUD implanted in the anterior suprachoroidal space may be of interest in the treatment of intraocular inflammation