Optical coherence tomography biomarkers in early and intermediate age-related macular degeneration: A clinical guide.

Advanced forms of age-related macular degeneration (AMD), characterised by atrophic and neovascular changes, are a leading cause of vision loss in the elderly population worldwide. Prior to the development of advanced AMD, a myriad of risk factors from the early and intermediate stages of AMD have been published in the scientific literature over the last years. The ability to precisely recognise structural and anatomical changes in the ageing macula, altogether with the understanding of the individual risk implications of each one of them is key for an accurate and personalised diagnostic assessment. The present review aims to summarise updated evidence of the relative risk conferred by diverse macular signs, commonly seen on optical coherence tomography, in terms of progression to geographic atrophy or macular neovascularization. This information may also serve as a basis for tailored follow-up monitoring visits.

Improvement of objective ocular redness measured with Keratograph 5M in glaucoma patients after instilling brimonidine drops.

OBJECTIVE: To compare objective ocular redness measured using OCULUS Keratograph 5 M before and after 0.2% brimonidine instillation in glaucoma patients under topical hypotensive treatment. METHODS: 60 eyes from 60 subjects diagnosed with glaucoma or ocular hypertension under hypotensive ocular topical treatment were analyzed. Basal Ophthalmological examination was performed.Outcome variables were OCULUS Keratograph 5 M redness scores (RS) before and after 0.2% brimonidine instillation; overall, bulbar temporal (BT), bulbar nasal (BN), limbar temporal (LT), and limbar nasal (LN); non-invasive average tear film breakup time (Nia-BUT), non-invasive first tear film breakup time (Nif-BUT) and meibography. In addition, the following clinical data were collected: intraocular pressure, type, duration, amount, and preservatives/or not of hypotensive treatment, fluorescein corneal staining score and lower tear meniscus height. RESULTS: All eyes were under topical medication. All redness scores were reduced after brimonidine instillation, mean RS differences were BT 0.82 ± 0.62, BN hyperemia 1.03 ± 0.55, LN hyperemia 0.84 ± 0.49, LT hyperemia 0.71 ± 0.50 and total hyperemia 0.91 ± 0.52 (all p < 0.001). 30 min after brimonidine instillation mean overall RS reduction was 47.97 ± 12.39% (p < 0.001) and after 1 h there was a persistent reduction of overall RS of 45.92 ± 14.27% (p < 0.001). Hyperemia reduction was significant and comparable between preservative and preservative-free group 0.12 ± 0.14 (p > 0.392) and between patient with combination therapy and monotherapy 0.16 ± 0.14 (p > 0.258). CONCLUSION: A significant reduction of conjunctival hyperemia was objectively found in glaucoma patients under topical hypotensive treatment before and after brimonidine instillation. Its fast and long-lasting effect may be useful preoperatively in glaucoma patients to reduce intraoperative bleeding and associated complications.

Anterior Scleral Thickness and Other Dimensions in Nanophthalmos by Swept-Source Optical Coherence Tomography: A Comparative Study.

PURPOSE: The purpose of this study is to assess the ocular dimensions of the anterior and posterior segment, including the anterior scleral thickness (AST) in nanophthalmos compared to control eyes. METHODS: A cross-sectional comparative study was carried out in two groups: 46 eyes of 28 patients with nanophthalmos, defined as axial length (AXL) < 20.5 mm, and 60 eyes of 30 controls paired by age and sex. The AST and ocular wall thickness (OWT) were measured by optical coherence tomography in the temporal and nasal quadrants at 1, 2, and 3 mm from the scleral spur. Also, the anterior chamber depth (ACD), white-to-white (WTW), lens thickness (LT), subfoveal choroidal thickness (SFCT), and retinal thickness (RT) were evaluated. RESULTS: The mean AXL was 19.3 ± 1.5 mm in the nanophthalmos group and 23.9 ± 1.1 mm in the control group (p < 0.001). The OWT was thicker in all measurement points in nanophthalmos (p < 0.001). There were no differences in the AST measurements between groups, except for the AST1 and the AST3 in the nasal quadrant. ACD was shallower and LT was thicker in nanophthalmos, with WTW being larger in controls (p < 0.001). SFCT and RT were thicker in nanophthalmos compared to healthy individuals (p < 0.001). CONCLUSIONS: Significant anatomical differences are found in nanophthalmic eyes. They present a shallower ACD; thicker LT, OWT, choroid, and retina; and smaller WTW diameter-although no relevant differences in the AST were observed.

Comparison of intraocular pressure measurements between Easyton transpalpebral tonometry and Perkins, iCare iC100 and Corvis ST, and the influence of corneal and anterior scleral thickness.

PURPOSE: To compare intraocular pressure (IOP) measurements between Easyton transpalpebral tonometry and Perkins, iCare iC100 and Corvis ST. Also, to assess the influence of corneal characteristics and anterior scleral thickness (AST) on the IOP measurements. METHODS: Sixty-nine eyes from 69 healthy subjects were included. IOP was measured by Easyton, Perkins, iC100 and Corvis ST (corrected IOP, bIOP; and non-corrected IOP, IOPnct). Other variables studied were AST, axial length (AL), and Corvis parameters: Length 1, velocity 1, length 2, velocity 2, peak distance, radius, deformation amplitude, and central corneal thickness (CCT). Pearson correlation, limits of agreement (LoA), and multiple regression analysis were calculated. RESULTS: No significant differences in IOP between Easyton and Perkins, iC100, and bIOP were observed (all p > 0.05), being significant only between Perkins and IOPnct ( - 1.49 mmHg, p < 0.001). Bland-Altman graphs showed that the mean difference between Perkins and Easyton was 0.07 mmHg (p < 0.001), and LoA - 7.49 to + 7.39 mmHg. Significant correlations were found between the measurements of Perkins and iC100, IOPnct, bIOP (r = 0.710, 0.628, 0.539; p < 0.001 respectively), iC100 and IOPnct, bIOP (r = 0.627, 0.513; p < 0.001, respectively). The multivariate regression analysis revealed that differences between Perkins and Easyton (adjusted R2 = 0.25) were influenced by AL (B = 1.28, p < 0.008), length 1 (B = 3.13, p < 0.018), and the radius (B = 1.26, p < 0.010). Differences between Perkins and bIOP (adjusted R2 = 0.21) were affected by the CCT (B = 0.029, p < 0.003). CONCLUSIONS: There are no significant differences in the IOP measurements between Perkins and Easyton, iC100 or bIOP. Length 1, radius, and CCT have limited influence on these differences, while AST did not show any effect.

Easyton® transpalpebral versus Perkins applanation tonometry in different populations.

OBJECTIVE:  To compare intraocular pressure (IOP) measurements obtained using the new transpalpebral Easyton® tonometer and Perkins applanation tonometer (PAT) in three different clinical populations. METHODS: The participants of this prospective study were 84 subjects divided into the groups: 22 healthy children (G1), 42 healthy adults (G2), and 20 adult patients with primary open angle glaucoma (G3). The data recorded in 84 eyes of these subjects were age, sex, gender, central corneal thickness (CCT), and axial length (AL). In all eyes, IOP was determined in the same examination room by the same experienced examiner using Easyton® and PAT in random order. RESULTS:  Mean differences in IOP readings between Easyton® and PAT were 0.45 ± 1.97 (p = 0.295), - 0.15 ± 2.13 (p = 0.654), - 1.65 ± 3.22 (p = 0.033), and - 0.018 ± 2.50 mmHg (p = 0.500) in the groups G1, G2, G3, and whole sample (G4), respectively. Correlations between Easyton® and PAT IOP values were 0.668 (p = 0.001) for G1, 0.463 (p = 0.002) for G2, 0.680 (p < 0.001) for G3, and 0.605 (p < 0.001) for G4. Moderate to good agreement between the two tonometers was found in all groups according to intraclass correlation coefficients, which were 0.794 (p < 0.001) for G1, 0.632 (p < 0.001) for G2, 0.809 (p < 0.001) for G3, and 0.740 (p < 0.001) for G4. The lower and upper limits of agreement between the devices were - 5.1 and 4.7 mmHg, respectively, in the complete group. No correlation was noted between CCT or AL and the Easyton® IOP measurements. CONCLUSION: IOP measurements obtained with Easyton® and PAT show an acceptable level of agreement mainly in healthy individuals, recommending it for IOP screening in children and in patients in which PAT measurement may be impared as patients with hemifacial spasms, corneal irregularities, or reduced mobility. It is not recommended for glaucoma patients follow-up.

Toxoplasmic maculopathy with bacillary layer detachment in a pediatric patient.

We report the case of a 14-year-old girl with ocular toxoplasmosis presenting with severe panuveitis with anterior segment involvement, moderate vitreous haze, focal retinochoroiditis, extensive retinal periphlebitis, and macular bacillary layer detachment. Toxoplasmosis treatment was complicated by Stevens-Johnson syndrome, which developed 8 days after starting trimethoprim-sulfamethoxazole.

Spontaneous Descemet Layer Dissection Without Pneumodissection in Femtosecond Laser-Assisted Mushroom-Type Deep Anterior Lamellar Keratoplasty.

PURPOSE: The aim of this study was to describe a case of spontaneous Descemet layer dissection without pneumodissection in femtosecond laser-assisted mushroom-type deep anterior lamellar keratoplasty. METHODS: This study is a case report. RESULTS: A 46-year-old woman diagnosed with reticular dystrophy underwent, in her left eye, mushroom configuration femtosecond laser-assisted DALK (F-DALK). After laser trephination and removal of the superficial stroma using manual dissection, a type 2 BB formation was observed intraoperatively in the AS-OCT without signs of an associated microperforation. A deeper stromal removal was accomplished by layer-by-layer manual dissection, while the BB persisted. After stromal dissection, the donor cornea was secured with 8 interrupted 10-0 nylon sutures. The next day AS-OCT showed a detachment of DM. After 1 week, a spontaneous resolution of the DM detachment was observed. CONCLUSIONS: This unknown F-DALK intraoperative complication has been detected through intraoperative AS-OCT images which may improve our understanding of F-DALK surgery and possible complications associated with femtolaser-assisted procedures.

NASYM, a live intranasal vaccine, protects young calves from bovine respiratory syncytial virus in the presence of maternal antibodies.

BACKGROUND: Bovine respiratory syncytial virus (BRSV) is a major problem for cattle worldwide during their first year of life. The aim of the present study was to evaluate efficacy and longevity of immunity of a live vaccine (NASYM, HIPRA) in the presence of maternally derived antibodies (MDA). METHOD: Calves (36) were distributed in four groups, based on MDA status and treatment. They received NASYM or a placebo at an early age (less than two weeks) by intranasal route. Eight weeks later, animals were challenged with the Asquith strain of BRSV. Efficacy was assessed by monitoring clinical signs and mortality, PaO2 , virus shedding and lung lesions. The immunological response was evaluated by measuring IgG in serum and IgA in nasal secretions. RESULTS: A reduction of mortality, lung lesions, shedding and a higher PaO2 was achieved in NASYM vaccinated groups, independently of MDA status. An anamnestic IgG response was observed after challenge in vaccinated animals, both in MDA+ and MDA- groups. An IgA response was also observed in vaccinated animals after vaccination and challenge. CONCLUSION: NASYM protected newborn calves with MDAs during the first 10 weeks of life, against a very virulent challenge that caused extensive pulmonary lesions and deaths in control animals, with just a single intranasal dose.

Local Inflammation, Dissemination and Coalescence of Lesions Are Key for the Progression toward Active Tuberculosis: The Bubble Model.

The evolution of a tuberculosis (TB) infection toward active disease is driven by a combination of factors mostly related to the host response. The equilibrium between control of the bacillary load and the pathology generated is crucial as regards preventing the growth and proliferation of TB lesions. In addition, some experimental evidence suggests an important role of both local endogenous reinfection and the coalescence of neighboring lesions. Herein we propose a mathematical model that captures the essence of these factors by defining three hypotheses: (i) lesions grow logistically due to the inflammatory reaction; (ii) new lesions can appear as a result of extracellular bacilli or infected macrophages that escape from older lesions; and (iii) lesions can merge when they are close enough. This model was implemented in Matlab to simulate the dynamics of several lesions in a 3D space. It was also fitted to available microscopy data from infected C3HeB/FeJ mice, an animal model of active TB that reacts against Mycobacterium tuberculosis with an exaggerated inflammatory response. The results of the simulations show the dynamics observed experimentally, namely an initial increase in the number of lesions followed by fluctuations, and an exponential increase in the mean area of the lesions. In addition, further analysis of experimental and simulation results show a strong coincidence of the area distributions of lesions at day 21, thereby highlighting the consistency of the model. Three simulation series removing each one of the hypothesis corroborate their essential role in the dynamics observed. These results demonstrate that three local factors, namely an exaggerated inflammatory response, an endogenous reinfection, and a coalescence of lesions, are needed in order to progress toward active TB. The failure of one of these factors stops induction of the disease. This mathematical model may be used as a basis for developing strategies to stop the progression of infection toward disease in human lungs.

Multifaceted role of TREX2 in the skin defense against UV-induced skin carcinogenesis.

TREX2 is a 3'-DNA exonuclease specifically expressed in keratinocytes. Here, we investigated the relevance and mechanisms of TREX2 in ultraviolet (UV)-induced skin carcinogenesis. TREX2 expression was up-regulated by chronic UV exposure whereas it was de-regulated or lost in human squamous cell carcinomas (SCCs). Moreover, we identified SNPs in the TREX2 gene that were more frequent in patients with head and neck SCCs than in healthy individuals. In mice, TREX2 deficiency led to enhanced susceptibility to UVB-induced skin carcinogenesis which was preceded by aberrant DNA damage removal and degradation as well as reduced inflammation. Specifically, TREX2 loss diminished the up-regulation of IL12 and IFNγ, key cytokines related to DNA repair and antitumor immunity. In UV-treated keratinocytes, TREX2 promoted DNA repair and passage to late apoptotic stages. Notably, TREX2 was recruited to low-density nuclear chromatin and micronuclei, where it interacted with phosphorylated H2AX histone, which is a critical player in both DNA repair and cell death. Altogether, our data provide new insights in the molecular mechanisms of TREX2 activity and establish cell autonomous and non-cell autonomous functions of TREX2 in the UVB-induced skin response.

To achieve an earlier IFN-γ response is not sufficient to control Mycobacterium tuberculosis infection in mice.

The temporo-spatial relationship between the three organs (lung, spleen and lymph node) involved during the initial stages of Mycobacterium tuberculosis infection has been poorly studied. As such, we performed an experimental study to evaluate the bacillary load in each organ after aerosol or intravenous infection and developed a mathematical approach using the data obtained in order to extract conclusions. The results showed that higher bacillary doses result in an earlier IFN-γ response, that a certain bacillary load (BL) needs to be reached to trigger the IFN-γ response, and that control of the BL is not immediate after onset of the IFN-γ response, which might be a consequence of the spatial dimension. This study may have an important impact when it comes to designing new vaccine candidates as it suggests that triggering an earlier IFN-γ response might not guarantee good infection control, and therefore that additional properties should be considered for these candidates.

Damaging role of neutrophilic infiltration in a mouse model of progressive tuberculosis.

Tuberculosis was studied using an experimental model based on the C3HeB/FeJ mouse strain, which mimics the liquefaction of caseous necrosis occurring during active disease in immunocompetent adults. Mice were intravenously infected with 2 × 10(4) Colony Forming Units of Mycobacterium tuberculosis and their histopathology, immune response, bacillary load, and survival were evaluated. The effects of the administration of drugs with anti-inflammatory activity were examined, and the C3H/HeN mouse strain was also included for comparative purposes. Massive intra-alveolar neutrophilic infiltration led to rapid granuloma growth and coalescence of lesions into superlesions. A central necrotic area appeared showing progressive cellular destruction, the alveoli cell walls being initially conserved (caseous necrosis) but finally destroyed (liquefactive necrosis). Increasing levels of pro-inflammatory mediators were detected in lungs. C3HeB/FeJ treated with anti-inflammatory drugs and C3H/HeN animals presented lower levels of pro-inflammatory mediators such as TNF-α, IL-17, IL-6 and CXCL5, a lower bacillary load, better histopathology, and increased survival compared with untreated C3HeB/FeJ. The observation of massive neutrophilic infiltration suggests that inflammation may be a key factor in progression towards active tuberculosis. On the basis of our findings, we consider that the C3HeB/FeJ mouse model would be useful for evaluating new therapeutic strategies against human tuberculosis.

The scavenger protein apoptosis inhibitor of macrophages (AIM) potentiates the antimicrobial response against Mycobacterium tuberculosis by enhancing autophagy.

Apoptosis inhibitor of macrophages (AIM), a scavenger protein secreted by tissue macrophages, is transcriptionally regulated by the nuclear receptor Liver X Receptor (LXR) and Retinoid X Receptor (RXR) heterodimer. Given that LXR exerts a protective immune response against M. tuberculosis, here we analyzed whether AIM is involved in this response. In an experimental murine model of tuberculosis, AIM serum levels peaked dramatically early after infection with M. tuberculosis, providing an in vivo biological link to the disease. We therefore studied the participation of AIM in macrophage response to M. tuberculosis in vitro. For this purpose, we used the H37Rv strain to infect THP-1 macrophages transfected to stably express AIM, thereby increasing infected macrophage survival. Furthermore, the expression of this protein enlarged foam cell formation by enhancing intracellular lipid content. Phagocytosis assays with FITC-labeled M. tuberculosis bacilli indicated that this protein was not involved in bacterial uptake; however, AIM expression decreased the number of intracellular cfus by up to 70% in bacterial killing assays, suggesting that AIM enhances macrophage mycobactericidal activity. Accordingly, M. tuberculosis-infected AIM-expressing cells upregulated the production of reactive oxygen species. Moreover, real-time PCR analysis showed increased mRNA levels of the antimicrobial peptides cathelicidin and defensin 4B. These increases were concomitant with greater cellular concentrations of the autophagy-related molecules Beclin 1 and LC3II, as well as enhanced acidification of mycobacterial phagosomes and LC3 co-localization. In summary, our data support the notion that AIM contributes to key macrophage responses to M. tuberculosis.

Evolution and role of corded cell aggregation in Mycobacterium tuberculosis cultures.

The aim of this study was to evaluate the evolution and role of corded cell aggregation in Mycobacterium tuberculosis cultures according to growth time and conditions. Thus, in standard culture using aerated 7H9 Middlebrook broth supplemented with 0.05% Tween 80, a dramatic CFU decrease was observed at the end of the exponential phase. This phase was followed by a stable stationary phase that led to dissociation between the optical density (O.D.) and CFU values, together with the formation of opaque colonies in solid culture. Further analysis revealed that this was due to cording. Scanning electron microscopy showed that cording led to the formation of very stable coiled structures and corded cell aggregations which proved impossible to disrupt by any of the physical means tested. Modulation of cording with a high but non-toxic concentration of Tween 80 led to a slower growth rate, avoidance of a sudden drop-off to the stationary phase, the formation of weaker cording structures and the absence of opaque colonies, together with a lower survival at later time-points. An innovative automated image analysis technique has been devised to characterize the cording process. This analysis has led to important practical consequences for the elaboration of M. tuberculosis inocula and suggests the importance of biofilm formation in survival of the bacilli in the extracellular milieu.

Ibuprofen therapy resulted in significantly decreased tissue bacillary loads and increased survival in a new murine experimental model of active tuberculosis.

C3HeB/FeJ mice infected with Mycobacterium tuberculosis were used in an experimental animal model mimicking active tuberculosis in humans to evaluate the effect of antiinflammatory agents. No other treatment but ibuprofen was given, and it was administered when the animals' health started to deteriorate. Animals treated with ibuprofen had statistically significant decreases in the size and number of lung lesions, decreases in the bacillary load, and improvements in survival, compared with findings for untreated animals. Because antiinflammatory agents are already on the market, further clinical trials should be done to evaluate this effect in humans as soon as possible, to determine their suitability as coadjuvant tuberculosis treatment.

Low dose aerosol fitness at the innate phase of murine infection better predicts virulence amongst clinical strains of Mycobacterium tuberculosis.

BACKGROUND: Evaluation of a quick and easy model to determine the intrinsic ability of clinical strains to generate active TB has been set by assuming that this is linked to the fitness of Mycobacterium tuberculosis strain at the innate phase of the infection. Thus, the higher the bacillary load, the greater the possibility of inducting liquefaction, and thus active TB, once the adaptive response is set. METHODOLOGY/PRINCIPAL FINDINGS: The virulence of seven clinical Mycobacterium tuberculosis strains isolated in Spain was tested by determining the bacillary concentration in the spleen and lung of mice at weeks 0, 1 and 2 after intravenous (IV) inoculation of 104 CFU, and by determining the growth in vitro until the stationary phase had been reached. Cord distribution automated analysis showed two clear patterns related to the high and low fitness in the lung after IV infection. This pattern was not seen in the in vitro fitness tests, which clearly favored the reference strain (H37Rv). Subsequent determination using a more physiological low-dose aerosol (AER) inoculation with 10² CFU showed a third pattern in which the three best values coincided with the highest dissemination capacity according to epidemiological data. CONCLUSIONS/SIGNIFICANCE: The fitness obtained after low dose aerosol administration in the presence of the innate immune response is the most predictive factor for determining the virulence of clinical strains. This gives support to a mechanism of the induction of active TB derived from the dynamic hypothesis of latent tuberculosis infection.