A pilot study on corneal Langerhans cells in keratoconus

A pilot study on Langerhans cells in keratoconus patients by in vivo confocal microscopy before and after corneal cross-linking and correlation with eye rubbing

PURPOSE

The aim of this study was to investigate the corneal microstructure and Langerhans cells using in vivo confocal microscopy in keratoconus patients before and after cross-linking, and to correlate the morphologic findings with clinical and patient-reported outcomes, including eye rubbing (ER) behavior.

METHODS

Patients with progressive keratoconus undergoing iontophoresis-assisted epithelium-on cross-linking (I-CXL) were consecutively enrolled. In vivo confocal microscopy was performed before and 6 months after treatment. Patients were asked to quantify their ER behavior on a Visual Analogue Scale (VAS) and completed the Keratoconus Outcomes Research Questionnaire and the Ocular Surface Disease Index questionnaires at the same time points. Visual acuity, tear osmolarity, topography, aberrometry, and pachymetry of both eyes were assessed.

RESULTS

Thirteen patients were included in this pilot study. Preoperatively, the mean Langerhans cells density was 35,615 cells per mm2, and the median morphology was 3. The mean ER VAS before treatment was 7,077 out of 10. The ER VAS showed significant positive correlations with both Langerhans cells density and morphology of the study eye. After treatment, a statistically significant reduction in ER VAS and in Langerhans cells variables was observed. The mean sub-basal plexus nerve density was comparable to pre-operative values 6 months after I-CXL.

CONCLUSIONS

Based on this preliminary evidence, the presence of high density of mature Langerhans cells in the central cornea of keratoconus patients and its correlation with eye rubbing support the role of inflammation in keratoconus. The reduction in these markers after treatment may suggest a potential of CXL in moderating immune-related inflammation and eye rubbing in the medium term.

Integrated analysis of murine cornea identifies JAK/STAT signaling pathway upregulated specifically in female Vitamin A Deficient mice

The Keratoconus (KC) is a corneal ectatic disease with unclear etiology. There are increasing studies that reported its association with a variety of inflammatory mechanisms. Vitamin A(VA) is an important nutrient related to inflammation regulation, and its deficiency may cause abnormalities of the ocular surface. However, the proportion of Vitamin A deficiency(VAD) was found surprisingly high among KC patients in our clinic practice. The aim of this study is to explore the effects of VAD on the transcriptome of corneas with the help of the VAD murine model and transcriptomics techniques. Blood samples of KC patients and non-KC controls (NC) were collected and the serum VA concentrations were measured and analyzed. A total of 52 NC and 39 KC were enrolled and the comparison of serum VA showed that the proportion of VAD in KC patients was 48.7% versus 1.9% in NC group. The further analysis of gender differences showed the proportion of VAD in female KC was 88.9% versus 36.7% in KC male patients. To explore the influence of VAD on cornea, the VAD mice fed with VAD diets were used. The RNA sequencing was employed to compare the corneal transcriptomic characteristics between the VAD female mice, NC female mice, VAD male mice and NC male mice. The transcriptome analysis revealed that the upregulated differential genes were mainly enriched in the immune response related pathways in VAD female mice versus NC female mice, especially the genes of JAK-STAT signaling pathway. The downstream molecules of JAK-STAT pathway were also significant after corneal mechanical scratching in female VAD mice. While, the differential genes between VAD male mice and NC male mice were estrogen signaling pathway instead of JAK-STAT pathway. This study indicates that VAD affects the transcriptomics of murine cornea with gender differences, which specifically affects the inflammatory status of the female murine cornea.

The Diagnostic Value of Neutrophil to Lymphocyte Ratio as an Effective Biomarker for Eye Disorders: A Meta-Analysis

The neutrophil to lymphocyte ratio (NLR) reflects a dynamic relationship between the innate (neutrophils) and adaptive (lymphocytes) cellular immune response. This systematic review and meta-analysis was conducted to critically evaluate the literature regarding the use of the NLR as a reliable means to detect several ocular disorders. Our study was registered with the PROSPERO (ID: CRD42022314850). Three databases, including PubMed, Embase, Scopus, and the Web of Science, were searched on September 9, 2022, with no restrictions on the article's language. Finally, 32 articles were recognized as eligible for our meta-analysis. We found that patients with eye diseases had significantly elevated levels of NLR in comparison to healthy controls (SMD =0.53, 95% CI =0.35-0.71, P < 0.001). In subgroup analysis, patients with keratoconus (SMD =0.69; 95% CI =0.33-1.05, P < 0.001), glaucoma (SMD =0.56, 95% CI =0.25-0.87, P < 0.001), pterygium (SMD =0.14; 95% CI =0.01-0.26, P < 0.001), and idiopathic epiretinal membrane (SMD =0.14; 95% CI =0.01-0.26, P < 0.001) had higher levels of NLR compared to healthy controls. However, NLR levels of patients with dry eye disease were similar to healthy controls (SMD =0.32, 95% CI = -0.49-1.13, P = 0.435). It can be said that NLR is a valuable marker of systemic inflammation, which is significantly increased in many eye disorders, suggesting that inflammation plays a key role in the pathophysiology of these diseases.

[Nerve fiber structure after different types of corneal transplantation]

This review presents basic information about the state of corneal nerve fibers and Langerhans cells before and after keratoplasty. Keratoplasty is a common corneal surgery that carries a risk of graft rejection. The state of corneal nerve fibers can vary after different types of keratoplasty. Corneal confocal microscopy allows in vivo evaluation of the cornea, which can help assess the condition of corneal nerve fibers, as well as reveal the presence of Langerhans cells. Further research in this direction would contribute to identifying the relationship between the state of corneal nerve fibers, the presence of Langerhans cells, and graft rejection.

Tear Levels of Inflammatory Cytokines in Keratoconus: A Meta-Analysis of Case-Control and Cross-Sectional Studies

Purpose

To assess the tear levels of inflammatory cytokines in patients with keratoconus (KC).

Design

Systemic review and meta-analysis.

Methods

The following electronic databases and search engine were searched: PubMed, EMBASE, Web of Science, and Google Scholar. A systematic search of all relevant studies published through January 2021 was conducted, and the standardized mean difference (SMD) and 95% confidence interval (CI) of cytokine levels were calculated to estimate the pooled effects. Sensitivity analysis, subgroup analysis, and metaregression were applied to explore the sources of heterogeneity.

Results

A total of 7 studies with 374 participants (374 eyes) from clinical studies were included. The tear levels of interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α) were significantly increased in KC compared with normal controls. The SMD of IL-1β was 1.93 (95% CI 0.22 to 3.65, P = 0.03). The SMD of IL-6 was 1.22 (95% CI 0.59 to 1.84, P < 0.001). The SMD of TNF-α was 1.75 (95% CI 0.66 to 2.83, P = 0.002). There was no significant difference between the two groups on interleukin-4 (IL-4) and interleukin-10 (IL-10). The SMD for IL-4 was 2.36 (95% CI -0.28 to 5.00, P = 0.08) and for IL-10 was 0.30 (95% CI -1.29 to 1.89, P = 0.71). Meta-regression analysis indicated that the heterogeneity maybe significantly correlated with the method of detection, the different ages, and the source of population.

Conclusions

Our meta-analysis demonstrated that proinflammatory cytokines IL-1β, IL-6, and TNF-α were increased, indicating that cytokine profile changed in KC tears and inflammation may play an important role in the pathogenesis and development of KC.

Systemic immune-inflammation index, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio levels are associated with keratoconus

Purpose:

The aim of this study was to assess the systemic immune-inflammation index (SII) levels, neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) in patients with keratoconus (KC).

Methods:

A total of 42 patients with KC (KC group) and 42 age- and sex-matched healthy subjects (control group) were included into this cross sectional study. Complete blood count parameters were assayed. SII, NLR, red cell distribution width (RDW), and PLR values were calculated. The SII value was calculated as follows: platelet count × (neutrophil/lymphocyte).

Results:

SII, NLR, RDW, and PLR values were significantly higher in KC group compared to control group [709 ± 236 vs. 418 ± 117 (P < 0.001), 2.5 ± 0.8 vs. 1.76 ± 0.3 (P < 0.001), 14.3 ± 1.6% vs. 12.9 ± 0.54% (P < 0.001), and 143 ± 36 vs. 106 ± 23 (P < 0.001), respectively]. Using the receiver operating characteristics (ROC) curve analysis to predict KC, the highest area under the curve (AUC) was determined SII (0.846 for SII, 0.778 for NLR, and 0.796 for PLR).

Conclusion:

SII, NLR, RDW, and PLR levels were significantly increased in patients with KC. This study supports the idea that several inflammatory pathways may play important role in the pathogenesis of this disorder. SII may be much better marker than NLR and PLR for predicting the inflammatory status of the disease.

[The effects of corneal collagen cross-linking on the corneal structure in keratoconus]

The article reviews the key information regarding morphological changes in keratoconic corneas and dramatic alterations of the corneal tissue induced by corneal cross-linking according to data obtained with in vivo corneal confocal microscopy, presents basic information on keratoconus visualization techniques widely used for diagnosis, monitoring of ectasia, as well as efficacy assessment of its treatment, and lists basic principles of corneal cross-linking procedure and confocal microscopy with consideration of morphology specifics of keratoconic corneas. The article also discusses prospective benefits of further research and longitudinal studies aimed to define the origin of keratoconus and to develop advanced corneal cross-linking protocols.

Protecting the Ocular Surface at the Time of Cataract Surgery: Intracameral Mydriatic and Anaesthetic Combination Versus A Standard Topical Protocol

Introduction

An intracameral mydriatic and anaesthetic combination has been approved for injection into the anterior chamber in order to provide rapid and stable mydriasis and sustained intraocular anaesthesia during cataract surgery.

Methods

In this prospective study, conducted at the Eye Clinic, University of Florence, Italy, we compared phacoemulsification using the standard mydriatic-anaesthetic eye-drop protocol with that using the standard protocol in terms of corneal changes, ocular surface parameters and visual quality. Sixty patients (60 eyes) were included in the study, with 30 eyes receiving Mydrane®, a novel injectable intracameral solution, during phacoemulsification (Mydrane protocol, MP) and 30 eyes receiving the standard mydriatic-anaesthetic eye drops (standard protocol, SP). The following parameters were assessed using in vivo confocal microscopy (IVCM): central corneal thickness (CCT); flare and cells in the aqueous humor (Flare); keratocyte activation (KA), Langerhans’ cell density (LCD), nerve fibre density (NFD) and endothelial cell density (ECD). The Ocular Surface Disease Index (OSDI) score, tear breakup time (TBUT) and Schirmer’s test I (STI) were also evaluated. The Optical Scattering Index (OSI) and its standard deviation (OSI-SD) were assessed using the Optical Quality Analysing System (Visiometrics SL, Terrassa, Spain).

Results

In the MP group, CCT, Flare, KA and LCD values returned to baseline values within 15 postoperative days. The mean ECD and NFD decreased significantly in both groups from baseline at all follow-up assessments, with no statistically significant difference between groups. TBUT returned to the preoperative level at postoperative day 15 in the MP group. OSDI scores and STI were significantly worse in both groups at all follow-up assessments compared to baseline. At postoperative day 15 OSI and OSI-SD values were significantly better in the MP group than in the SP group.

Conclusions

The use of Mydrane during cataract surgery showed a good safety profile and few toxic side effects, ensuring better optical quality and tear film stability.

Ocular Surface Disease Index and Ocular Thermography in Keratoconus Patients

Purpose

Keratoconus (KC) has been defined as a “noninflammatory” corneal disease, but recent studies have noted a potential inflammatory origin. We analysed the Ocular Surface Disease Index (OSDI) and ocular surface temperature (OST) in KC patients compared to controls. Patients and Methods. A total of 179 eyes in 90 patients with KC (topographic keratoconus classification 0-1 to 4, age 36.1 ± 12.5 years, 65.9% males) and 82 eyes in 41 controls (age 36.4 ± 12.8 years, 47.6% males) were examined. The participants completed the OSDI questionnaire and underwent corneal topography, tomography, and thermography. Additional outcome measures were vision- and discomfort-related OSDI subscores and mean OST  at the corneal centre during 10 seconds of sustained eye opening after blinking.

Results

The OSDI score (31.4 ± 22.4 vs. 17.5 ± 17.9) and vision- (17.7 ± 14.6 vs. 10.5 ± 13.2) and discomfort-related (14.3 ± 10.7 vs. 9.4 ± 10.5) OSDI subscores were significantly higher in KC patients than in controls (p < 0.001). We found no significant difference in the central corneal OST (34.2 ± 0.6°C vs. 34.2 ± 0.7°C; p < 0.001). We found no significant difference in the central corneal OST (34.2 ± 0.6°C vs. 34.2 ± 0.7°C; p < 0.001). We found no significant difference in the central corneal OST (34.2 ± 0.6°C vs. 34.2 ± 0.7°C; r > 0.174, p < 0.001). We found no significant difference in the central corneal OST (34.2 ± 0.6°C vs. 34.2 ± 0.7°C; r > 0.174, r > 0.174,

Conclusion

KC patients had increased OSDI scores and vision- and discomfort-related OSDI subscores without an increase in the OST compared to a normal population. OSDI score/subscores weakly correlate with SAI and SRI but do not correlate with OST in KC patients or controls. Vision- and discomfort-related symptoms of KC have to be managed in parallel in ophthalmological practice, but the necessity of anti-inflammatory treatment cannot be verified through ocular thermography.

Keratoconus Could Be Associated With Psoriasis: Novel Findings From a Comparative Study

PURPOSE

To explore the relationship between keratoconus (KC) and psoriasis.

METHODS

One hundred ten eyes of 55 patients with psoriasis (study group, SG) and 110 eyes of age-sex-matched 55 healthy volunteers (control group, CG) were included in the study. All cases underwent a detailed dermatological and ophthalmological examination including corneal topography. Moreover, Psoriasis Area and Severity Index (PASI) scoring of the patients was carried out in the SG. A thorough comparison of pachymetric, aberrometric, and topometric values between the groups was performed, and the results were interpreted. A χ test, Mann-Whitney U test, and Pearson correlation test were used for statistical assessment.

RESULTS

Although the average Kmax (44.6 in the SG; 44.5 in the CG; P = 0.613) and Belin/Ambrósio enhanced ectasia total deviation value (1.34 in SG; 1.20 in CG; P = 0.880) were similar between the groups, the mean index of vertical asymmetry value in the SG (0.14 mm) was significantly higher than that in the CG (0.11 mm) (P = 0.041). Moreover, 28 eyes from 16 patients with psoriasis were found to be associated with KC because 26 of those 28 eyes were KC suspects and 2 of them were definite KC. A positive correlation was found among topometric parameters, especially between duration of the disease and PASI score. A negative correlation was discovered between topometric parameters and the early beginning of psoriasis.

CONCLUSIONS

Serious changes in topography maps may occur in psoriatic patients. The changes were found to be more evident in the presence of a higher PASI score and the early beginning and longer duration of the disease. The results hinted a potential relationship between psoriasis and KC.

Corneal confocal microscopy detects corneal nerve damage and increased dendritic cells in Fabry disease

Fabry disease is characterised by neuropathic pain and accelerated vascular disease. This study evaluates the utility of corneal confocal microscopy (CCM) to non-invasively quantify corneal nerve and endothelial cell morphology and dendritic cell (DC) density in relation to disease severity in subjects with Fabry disease. Seventeen consecutive participants with Fabry disease and 17 healthy control subjects were included in this cross-sectional study. Fabry disease severity was measured using the Mainz Severity Score Index (MSSI). Central corneal sensitivity was assessed with a contact corneal esthesiometer. There was a significant reduction in the corneal sensitivity (5.75 [5.25–6.00] vs. 6.00 [6.00-6.00] cm, P = 0.014), nerve fiber density (NFD) (26.4 ± 10.1 vs. 33.7 ± 7.9 fibers/mm², P = 0.025) and nerve fiber length (NFL) (15.9 ± 3.4 vs. 19.5 ± 4.4 mm/mm², P = 0.012) and an increase in DC density (38.3 [17.5–97.3] vs. 13.5 [0–29.4] cells/mm², P = 0.004) in subjects with Fabry disease compared to the healthy control subjects. The total MSSI score correlated with NFD (ρ = −0.686; P = 0.006), NFL (ρ = −0.692; P = 0.006), endothelial cell density (ρ = −0.511; P = 0.036), endothelial cell area (ρ = 0.514; P = 0.036) and α-galactosidase A enzyme activity (ρ = −0.723; P = 0.008). This study demonstrates reduced corneal sensitivity, corneal nerve fiber damage and increased DCs in subjects with Fabry disease.