Effect of contact lens wear on the release of tear mediators in keratoconus

Tear Cytokines as Predictive Biomarkers of Success in Contact Lens Discomfort Management

PURPOSE

To analyze changes in tear levels of inflammatory mediators in symptomatic contact lens (CL) wearers after refitting with daily disposable CLs and to identify potential biomarkers of success in CL discomfort (CLD) management.

METHODS

Symptomatic CL wearers (CLDEQ-8 ≥ 12) were refitted (V1) with daily disposable CLs (Delefilcon A). After one month (V2), participants were classified into the post-fitting non-symptomatic (CLDEQ <12) and symptomatic (CLDEQ ≥12) groups. At each visit, the participants were clinically evaluated, tears were collected, and 20 inflammatory mediators and substance P (SP) were measured using multiplex immunobead analysis and ELISA, respectively. The detection rates and concentrations were compared between visits and groups, and logistic regression models were performed.

RESULTS

Forty-three subjects (32 women/11 men; mean age: 23.2 ± 4.9 years) were enrolled. The IL-1β and IL-9 detection rates were higher at V2 (p ≤ 0.044). The detection rates of IL-1β, IL-9, MIP-1α/CCL3, and MMP-9 at V1 (p ≤ 0.045) and IL-17A at V2 (p ≤ 0.014) were higher in the post-fitting symptomatic group. The tear IL-9 concentration was increased at V2 (p = 0.018). The tear concentrations of fractalkine/CX3CL1, IL-2, IL-6, IL-10, MCP-3/CCL7, MIP-1β, NGF, RANTES/CCL5, and TNF-α were higher in the post-fitting symptomatic group (p ≤ 0.044). Additionally, levels of fractalkine/CX3CL1, IL-2, IL-6, IL-10, RANTES/CCL5, and TNF-α at V1 were significantly associated with the post-fitting grouping (p ≤ 0.044).

CONCLUSIONS

Low tear concentrations of specific inflammatory mediators may be used as a predictive biomarker of success for refitting symptomatic CL wearers with daily disposable CLs. However, complementary treatments might be required for symptomatic CL wearers with higher levels of these inflammatory molecules.

Evaluation of Corneal Parameters and Meibomian Gland Alterations After Corneal Cross-Linking in Patients With Progressive Keratoconus

OBJECTIVES

The aim of the study was to evaluate the changes in corneal parameters and meibomian gland alterations after corneal cross-linking (CXL) for progressive keratoconus.

METHODS

Thirty nine eyes of 39 keratoconus patients were treated with CXL. Corneal topography, specular microscopy, the Ocular Surface Disease Index© (OSDI), noninvasive tear break-up time (NITBUT), and meibography indices were evaluated preoperatively and at the first, third, and sixth months after CXL.

RESULTS

The flattest keratometry (K1) ( P =0.003), steepest keratometry (K2) ( P <0.001), apex, central, and thinnest corneal thicknesses ( P <0.001) showed significant differences after cross-linking, whereas the changes in the maximum keratometry (Kmax) were not significant ( P =0.140). The endothelial cell density, coefficient of variation, and hexagonality were unchanged. The NITBUT values decreased after cross-linking; however, there was no significant change in OSDI index ( P =0.313), meiboscore ( P =0.392), and meibomian gland loss degrees ( P =0.300). No change was detected in the morphology of the meibomian glands after CXL.

CONCLUSION

In eyes with keratoconus, a flattening in keratometry readings and thinning in corneal thickness were observed after CXL. The corneal endothelium is protected by dextran-free riboflavin. Cross-linking procedure causes dry eye by changing the corneal structure without affecting the morphology of the meibomian glands.

Keratoconus patients exhibit a distinct ocular surface immune cell and inflammatory profile

Inflammatory factors have been considered to contribute to keratoconus (KC) pathogenesis. This study aims to determine the immune cells subsets and soluble inflammatory factor profile on the ocular surface of KC patients. 32 KC subjects (51 eyes) across different grades of severity and 15 healthy controls (23 eyes) were included in the study. Keratometry and pachymetry measurements were recorded. Ocular surface immune cells (collected by ocular surface wash) immunophenotyped using flow cytometry include leukocytes, neutrophils, macrophages, natural killer (NK) cells, pan-T cells, gamma delta T (γδT) cells and NKT cells. Tear fluid collected using Schirmer's strip was used to measure 50 soluble factors by multiplex ELISA. Proportions of activated neutrophils, NK cells and γδT cells were significantly increased in KC patients. Significantly higher levels of tear fluid IL-1β, IL-6, LIF, IL-17A, TNFα, IFNα/β/γ, EPO, TGFβ1, PDGF-BB, sVCAM, sL-selectin, granzyme-B, perforin, MMP2, sFasL and IgE, along with significantly lower levels of IL-1α and IL-9 were observed in KC patients. Alterations observed in few of the immuno-inflammatory parameters correlated with grades of disease, allergy, eye rubbing and keratometry or pachymetry measurements. The observation implies a distinct immuno-inflammatory component in KC pathogenesis and its potential as an additional therapeutic target in KC management.

Risk Factors for Development of Keratoconus: A Matched Pair Case-Control Study

BACKGROUND

Keratoconus, a progressive ectatic corneal disorder, is believed to be multifactorial in etiology with interaction between genetic and environmental factors. To date, risk factors for the development of the disease are extensively debated and need to be identified since they play a critical role in disease prevention and management. This study aimed to analyze associations between several hereditary and environmental predictors and the development of keratoconus.

PATIENTS AND METHODS

This was a retrospective matched pair case-control study. The study was conducted in Ibn-Alhaitham eye teaching hospital between March 2016 and April 2017. Patients with keratoconus (cases) and their age- and gender-matched controls were asked about childhood and early teenage eye rubbing, ocular trauma, obesity, contact lens wear, smoking and sunlight exposure, family history of keratoconus, parental consanguinity and information related to socio-economic status. Univariable and multivariable conditional logistic regression analyses were used to test the significance of associations.

RESULTS

A total of 166 individuals (83 cases and 83 controls; 60.2% female) were included. On univariable analysis, eye rubbing, family history of keratoconus and parental consanguinity were significant risk factors for keratoconus, whereas all other factors were non-significant. On multivariable analysis, eye rubbing (odds ratio: 4.93; P < 0.01), family history of keratoconus (odds ratio: 25.52; P < 0.01) and parental consanguinity (odds ratio: 2.89; P = 0.02), again, emerged as significant risk factors for disease development.

CONCLUSION

Family history of keratoconus, eye rubbing, and parental consanguinity were significant risk factors for keratoconus development. These results support the evidence for multifactorial etiology, the most important factor being hereditary predisposition.

The Enigma of Environmental Factors in Keratoconus

Keratoconus is an ectatic disorder with highly complex and varied causes including genetic variations and environmental factors. Its prevalence varies widely between regions and countries. Many environmental factors have been proposed to be associated with keratoconus, but the interpretation of their individual contributions is difficult due to the presence of many confounding variables. The current literature was reviewed to evaluate the strength of the associations and the causative effects of environmental factors on keratoconus. Ethnicity and consanguinity have been revealed as important determinants for geographical variations in keratoconus prevalence. Eye rubbing, atopy, floppy eyelid syndrome, contact lens wear, pregnancy, and thyroid hormone disturbances are likely associated with keratoconus. The first 4 factors can induce ocular surface inflammation, matrix metalloproteinase release, and keratocyte apoptosis, consistent with the postulated etiology of keratoconus. The associations of keratoconus with UV exposure, cigarette smoking, personality, and sex were less convincing once confounding factors were considered. Future studies powered for multivariate analysis of factors discussed will hopefully shed light on what is truly important in the development and progression of keratoconus.

Biochemical Markers and Alterations in Keratoconus

Keratoconus (KC) is a corneal ectatic condition characterized by focal structural changes, resulting in progressive thinning, biomechanical weakening, and steeping of the cornea that can lead to worsening visual acuity due to irregular astigmatism and corneal scarring in more advanced cases. It is a relatively common ectatic disease of the cornea predominantly affecting the younger population. Despite its worldwide prevalence, its incidence is rather varied with a higher incidence among the Middle Eastern and South Asian population. Dysregulated corneal extracellular matrix remodeling underlies KC pathogenesis. However, a lack of absolute clarity regarding the factors that initiate and drive progression poses a significant challenge in its prevention and management. KC is a complex multifactorial disease as it is associated with a wide variety of etiological factors such as environmental stimuli/insults, oxidative stress, genetic predisposition, comorbidities, and eye rubbing. A series of studies using corneal tissues (epithelium, stroma), cultured corneal fibroblasts/keratocytes, tear fluid, aqueous humor, and blood from KC subjects has reported significant alterations in various biochemical factors such as extracellular matrix components, cellular homeostasis regulators, inflammatory factors, hormones, metabolic products, and chemical elements. It has become apparent that alterations in the biochemical mediators (related to various etiologies) could contribute to KC pathogenesis by altering the dynamics of extracellular matrix remodeling events such as collagen deposition, degradation, and cross-linking in the cornea. Determining key disease contributing biochemical mediators would aid in disease monitoring, prediction or abatement of disease progression, and development of targeted therapeutics to improve disease prognosis.

Update on Contact Lens Treatment of Keratoconus

Keratoconus (KC) is a progressive disease that leads to a decrease in visual acuity and quality and impairs vision-related quality of life. Contact lens (CL) application has a primary place and importance in the correction of the optic problems due to the disease. The corneal changes and increased irregular astigmatism that occur with KC progression necessitate special CL designs and fitting methods. In addition to disease stage, the patient's lens tolerance also plays a role in the application of CLs in KC patients. With recent advances in materials and design technology, the CLs used in the treatment of KC have developed considerably and there are various types available. In this review, we discuss the wide range of CLs, including rigid and soft lenses, hybrid and scleral lenses, and even custom lens designs, in light of recent scientific advances.

Effect of rigid gas permeable contact lens on keratoconus progression: a review

The prevalence of keratoconus is 1/2000 in the general population and is high in adolescents. Keratoconus is a progressive disease, which has a great impact on patients' quality of life and mental health. It can be managed by surgical and non-surgical means, rigid gas permeable (RGP) contact lens as its main non-surgical method is widely used in clinic. The efficacy of wearing RGP contact lens has been confirmed to some extent, but some studies have found that wearing RGP contact lens has adverse effects, which may promote disease progression. In this paper, the advantages and disadvantages of RGP contact lens in controlling keratoconus were reviewed to provide more suggestions and references for the clinical application of RGP contact lens.

Effect of long-term rigid gas-permeable contact lens wear on keratoconus progression

BACKGROUND/AIMS

To investigate the chronological corneal changes associated with long-term rigid gas-permeable contact lens (RGP-CL) wear in patients with keratoconus (KC).

METHODS

Clinical records of 405 patients with KC or with KC suspect were retrospectively reviewed. Patients with mild-to-moderate KC and uneventful follow-up were classified into the CL (RGP-CL wear) and non-CL (without CL wear) groups. Inclusion criteria were (1) at least 3-year follow-up and (2) Scheimpflug-based corneal imaging examination at each visit. The anterior (ARC) and posterior (PRC) radius of curvature obtained in a 3.0 mm optical zone, the thinnest pachymetry reading of the corneal thickness (Tmin), and maximum keratometry values (Kmax) were investigated as tomographic parameters.

RESULTS

Twenty-two and 15 patients who met the inclusion criteria were included in the CL and non-CL groups, respectively (31 and 20 eyes, respectively). The mean observation periods were 75 (CL group) and 63 (non-CL group) months. A multivariable non-linear regression analysis to assess the change in tomographic parameters over the follow-up period and difference of the trend between the two groups demonstrated no significant differences in the chronological change in ARC, PRC and Tmin between the CL and non-CL groups (p=0.318, p=0.280 and p=0.874, respectively).

CONCLUSION

Based on corneal tomographic evaluation over 5-6 years, the effects of long-term RGP-CL wear had no effect on KC progression.

Tear Inflammatory Molecules in Contact Lens Wearers: A Literature Review

Background:

Numerous studies have analysed the effect of using different Contact Lenses (CLs) or care solutions, and suffering discomfort or diseases associated with CL wear on the inflammatory mediator release into the tears.

Objective:

To summarize the published data on tear inflammatory molecules related to CL use.

Methods:

A PubMed-NCBI search has been conducted and those publications which carried out original investigations including the analysis of tear inflammatory mediators in CL wearers were selected.

Results:

Forty-three articles, from 1990 to 2019, have been included. Wearing hydrogel CLs, rigid gas permeable CLs, and special designs for irregular corneas in keratoconus patients (CLs with keratoconic design, hybrid CLs, piggyback fit, and scleral CLs) have been reported to alter the concentration of several molecules in tears. Moreover, there seems to be an effect of the wearing time and schedule, CL materials and designs, and care solutions used. Regarding CL discomfort, its relation with inflammatory mediators is not clear. However, some diseases associated to CL wear, such as giant papillary conjunctivitis, CL induced acute red eye, CL induced peripheral ulcer, and acanthamoeba keratitis have been related to the release of certain inflammatory mediators, which may serve as potential biomarkers.

Conclusion:

There is evidence suggesting that different aspects of CL wear alter the inflammatory mediator profile in tears, which may indicate an inflammatory state of the lacrimal functional unit. However, more studies need to be carried out to better understand how this inflammatory process works and its repercussion on the different aspects of CL wear.

Tear Mediators NGF along with IL-13 Predict Keratoconus Progression

Purpose: To find immunomediator combinations which could sensitively indicate keratoconus progression.Methods: Tear samples of 42 patients with keratoconus were collected at baseline and at the end of a one-year follow-up. The concentrations of 13 mediators were measured by CBA. Based on Pentacam HR examination, eyes were divided into a non-progressive and a progressive group.Results: At the end of the follow-up, significant differences were observed in the release of IFNγ, IL-13, IL-17A, CCL5, MMP-13 and PAI-1 between the two groups. Changes in five Pentacam parameters correlated positively with changes in IFNγ, IL-13, IL-17A, CXCL8, CCL5, TIMP-1 and t-PA. We found that tear level of IL-13 in combination with NGF can predict the progression of keratoconus with 100% specificity and 80% sensitivity.Conclusion: The findings of our longitudinal study may underscore the importance of NGF and IL-13 tear levels in the prediction of keratoconus progression.

Matrix metalloproteinases in keratoconus - Too much of a good thing?

Keratoconus (KC) is a progressive, early onset, and often bilateral eye condition, in which the cornea gradually weakens and bulges out, and in advanced cases may eventually become cone-shaped. The available evidence suggests that it is a multifactorial disease with environmental and genetic contributions. Matrix Metalloproteinases (MMPs) are a family of 24 zinc-dependent proteases with the ability to degrade collagen and other extracellular matrix (ECM) proteins, which are important components of the cornea. During the past two decades a growing body of literature has accumulated suggesting a link between MMPs and keratoconus. This article aims to summarize the current knowledge on the role of MMPs in the pathogenesis of KC. MMP-driven ECM remodelling is thought to be a necessary step for cornea healing, but a fine balance in the expression of MMPs is essential in maintaining the integrity and transparency of the cornea and for its correct healing, and an imbalance in this tightly regulated process may, in the long term, result in the progressive weakening of the cornea. There is extensive evidence that MMPs are upregulated in the corneal tissue and tears of KC patients, implicating dysregulated proteolysis in KC, with an increase in the level of some MMPs, particularly MMP-1 and MMP-9, confirmed in multiple independent studies. There is also evidence for a causative link between inflammation, which could result from the mechanical trauma due to contact lens wearing or/and eye rubbing, and the increased MMPs production observed in KC. However, the precise role of each MMP in the cornea is still unclear and the mechanisms causing their upregulation are mostly undiscovered. Further studies are required to verify the functional role of specific MMPs in KC development and assess the genetic association between common MMPs variants and risk of KC. As MMPs inhibitors are in development, this information could potentially drive the discovery of new treatments for KC.

Nonsurgical Procedures for Keratoconus Management

Objectives

To describe the past 20 years' correction modalities for keratoconus and their visual outcomes and possible complications.

Methods

A review of the published literature related to the visual outcomes and possible complications in the context of keratoconus management using nonsurgical procedures for the last 20 years (glasses and contact lenses) was performed. Original articles that reported the outcome of any correction modalities of keratoconus management were reviewed.

Results

The most nonsurgical procedure used on keratoconus management is the contact lens fitting. Soft contact lenses and soft toric contact lenses, rigid gas-permeable contact lenses, piggyback contact lens system, hybrid contact lenses, and scleral and corneoscleral contact lenses form the contemporary range of available lens types for keratoconus management with contact lenses. All of them try to restore the vision, improve the quality of life, and delay surgical procedures in patients with this disease. Complications are derived from the intolerance of using contact lens, and the use of each depends on keratoconus severity.

Conclusions

In the context of nonsurgical procedures, the use of contact lenses for the management of keratoconic patients represents a good alternative to restore vision and improve the quality of live in this population.

Inflammatory Biomarkers Profile as Microenvironmental Expression in Keratoconus

Keratoconus is a degenerative disorder with progressive stromal thinning and transformation of the normal corneal architecture towards ectasia that results in decreased vision due to irregular astigmatism and irreversible tissue scarring. The pathogenesis of keratoconus still remains unclear. Hypotheses that this condition has an inflammatory etiopathogenetic component apart from the genetic and environmental factors are beginning to escalate in the research domain. This paper covers the most relevant and recent published papers regarding the biomarkers of inflammation, their signaling pathway, and the potentially new therapeutic options in keratoconus.

The influence of rigid gas permeable lens wear on the concentrations of dinucleotides in tears and the effect on dry eye signs and symptoms in keratoconus

PURPOSE

To evaluate the signs and symptoms of dry eye and dinucleotide secretion in tears of keratoconus patients (KC) and the potential effect of rigid gas permeable (RGP) contact lens wear.

METHODS

Twenty-three KC patients and forty control subjects were enrolled in this study. Signs of dry eye including tear volume, tear stability and corneal staining along with symptoms were assessed using the McMonnies questionnaire. Tears were collected using Schirmer strips, and dinucleotide concentrations in collected tears measured using high pressure liquid chromatography. Values obtained in KC and controls were compared. The effect of contact lens wear in KC was also assessed.

RESULTS

KC eyes showed a significantly lower tear volume compared to controls, shorter tear break up time (TBUT), higher corneal staining and higher McMonnies dry eye questionnaire scores (p<0.05). When compared with non-wearers, KC contact lens wearers showed significantly higher symptoms, lower Schirmer and TBUT values (p<0.05). Concentration of Ap4A (0.695±0.304μM vs. 0.185±0.178μM) and Ap5A (0.132±0.128μM vs. 0.045±0.036μM) were higher in KC compared to controls (p<0.001) and only Ap4A was statistically higher in RGP wearers compared to non-wearers (0.794±0.478μM vs. 0.417±0.313μM) (p<0.05).

CONCLUSION

Signs and symptoms of dry eye as well as concentrations of Ap4A and Ap5A were markedly increased in KC patients compared to controls. Moreover, Ap4A and symptoms of dry eye were statistically higher in RGP wearers compared to non-wearers. This seems to indicate that factors such as RGP contact lens wear might exacerbate the clinical condition of dry eye.

Tear Mediators in Corneal Ectatic Disorders

Purpose

To compare the concentrations of 11 tear mediators in order to reveal the biochemical difference between pellucid marginal degeneration (PMD) and keratoconus (KC).

Methods

We have designed a cross-sectional study in which patients with corneal ectasia based on slit-lamp biomicroscopy and Pentacam HR (keratometry values (K1, K2, Kmax), astigmatism, minimal radius of curvature (Rmin), corneal thickness (Apex and Min), indices (surface variation, vertical asymmetry, keratoconus, central keratoconus, height asymmetry and decentration)) were enrolled. Eyes of keratoconic patients were similar to the PMD patients in age and severity (K2, Kmax and Rmin). Non-stimulated tear samples were collected from nine eyes of seven PMD patients, 55 eyes of 55 KC patients and 24 eyes of 24 healthy controls. The mediators’ (interleukin -6, -10, chemokine ligand 5, -8, -10, matrix metalloproteinase (MMP) -9, -13, tissue inhibitor of metalloproteinases (TIMP)-1, tissue plasminogen activator, plasminogen activator inhibitor, nerve growth factor) concentrations were measured using Cytometric Bead Array.

Results

MMP-9 was the only mediator which presented relevant variances between the two patient groups (p = 0.005). The ratios of MMP-9 and TIMP-1 were 2.45, 0.40 and 0.23 in PMD, KC and the controls, respectively.

Conclusion

As far as we are aware, this is the first study that aims to reveal the biochemical differences between PMD and KC. Further studies of biomarkers to investigate the precise role of these mediators need to be defined, and it is important to confirm the observed changes in a larger study to gain further insights into the molecular alterations in PMD.

Scheimpflug Imaging Parameters Associated with Tear Mediators and Bronchial Asthma in Keratoconus

Purpose. To determine associations between mediators in tears in the whole spectrum of keratoconus (KC); to explore connections between mediators and Scheimpflug parameters; to examine correlations between Scheimpflug parameters and bronchial asthma. Methods. Tear samples were collected from 69 patients and 19 controls. Concentrations of mediators—IL-6, -10; CXCL8, CCL5; MMP-9, -13; TIMP-1; t-PA, PAI-1—were measured by Cytometric Bead Array. Measured Pentacam parameters include keratometry values (K₁, K₂, K_max), corneal thickness (Pachy Pupil, Apex, Min), and elevations and indices (including Belin-Ambrósio deviation (BAD-D)). Results. A number of significant positive associations were observed between pairs of mediator concentrations. Significant positive correlations were found between BAD-D and CXCL8/MMP-9 and K₂ and MMP-9. Significant negative associations were explored between Pachy Min and CXCL8/t-PA. Significant associations were found between pairs of mediators (IL-6 and CXCL8; CCL5 and CXCL8/MMP-9; TIMP-1 and MMP-9/-13/t-PA; t-PA and CXCL8/CCL5/PAI-1) and the severity of KC. Significant positive correlation between asthma and the severity of KC was explored. Conclusion. Cooperation of different mediators in tears all taking part in the complex pathomechanism of keratoconus was revealed. Our research verifies that inflammation plays a crucial role in the pathogenesis of KC. Additionally this study confirms the effect of bronchial asthma on keratoconus.

Signs and Symptoms of Dry Eye in Keratoconus Patients: A Pilot Study

PURPOSE

To compare signs and symptoms of dry eye in keratoconus (KC) patients versus healthy subjects.

METHODS

A total of 15 KC patients (KC group, n = 15 eyes) and 16 healthy subjects (control group, 16 eyes) were enrolled in this study. The Schirmer I test with no anesthetic, tear break-up time (TBUT), corneal staining characteristics, and ocular surface disease index (OSDI) scores were evaluated for both groups. Impression cytology, combined with/scanning laser confocal microscopy (LCM), was performed to evaluate goblet cell density, mucin cloud height (MCH), and goblet cell layer thickness (CLT). Finally, tear concentrations of di-adenosine tetraphosphate (Ap4A) were assessed. Results were statistically analyzed using Shapiro-Wilk and non-parametric Wilcoxon rank sum tests. Statistical significance was set at p < 0.05.

RESULTS

KC patients had lower tear volumes and greater corneal staining than did healthy subjects (p < 0.05). OSDI scores were 44.96 ± 8.65 and 17.78 ± 6.50 for the KC and control groups, respectively (p < 0.05). We found no statistically significant differences in TBUT between groups. Impression cytology revealed lower goblet cell densities in KC group patients versus control group subjects (84.88 ± 32.98 and 128.88 ± 50.60 cells/mm,(2) respectively, p < 0.05). There was a statistically significant reduction in MCH and CLT in KC group patients compared with control group subjects. Ap4A tear concentrations were higher in KC group patients than in control group subjects (2.56 ± 1.10 and 0.15 ± 0.12 µM, respectively, p < 0.05).

CONCLUSIONS

The parameters evaluated in this study indicate that KC patients suffer greater symptoms of dry eye and greater tear instability, primarily due to the decreased mucin production in their tears, than do healthy patients with no KC.

Gross cystic disease fluid protein-15/prolactin-inducible protein as a biomarker for keratoconus disease

Keratoconus (KC) is a bilateral degenerative disease of the cornea characterized by corneal bulging, stromal thinning, and scarring. The etiology of the disease is unknown. In this study, we identified a new biomarker for KC that is present in vivo and in vitro. In vivo, tear samples were collected from age-matched controls with no eye disease (n = 36) and KC diagnosed subjects (n = 17). Samples were processed for proteomics using LC-MS/MS. In vitro, cells were isolated from controls (Human Corneal Fibroblasts-HCF) and KC subjects (Human Keratoconus Cells-HKC) and stimulated with a Vitamin C (VitC) derivative for 4 weeks, and with one of the three transforming growth factor-beta (TGF-β) isoforms. Samples were analyzed using real-time PCR and Western Blots. By using proteomics analysis, the Gross cystic disease fluid protein-15 (GCDFP-15) or prolactin-inducible protein (PIP) was found to be the best independent biomarker able to discriminate between KC and controls. The intensity of GCDFP-15/PIP was significantly higher in healthy subjects compared to KC-diagnosed. Similar findings were seen in vitro, using a 3D culture model. All three TGF-β isoforms significantly down-regulated the expression of GCDFP-15/PIP. Zinc-alpha-2-glycoprotein (AZGP1), a protein that binds to PIP, was identified by proteomics and cell culture to be highly regulated. In this study by different complementary techniques we confirmed the potential role of GCDFP-15/PIP as a novel biomarker for KC disease. It is likely that exploring the GCDFP-15/PIP-AZGP1 interactions will help better understand the mechanism of KC disease.

Tear film inflammatory mediators in patients with keratoconus

To determine the concentration of inflammatory mediators in the tear film of patients with keratoconus. Basal tears from patients with keratoconus and from normal controls were collected using a capillary tube. Patients with keratoconus were examined in a routine fashion, and keratometric readings were also taken from corneal topographic maps .The concentration of cytokines including Interleukin 6,10,1b and Interferon-γ was measured by enzyme-linked immunoadsorbent assay. Seventy-two subjects were enrolled in the study including 42 patients with keratoconus and 30 normals. Patients with keratoconus had significantly higher levels of Interlukin 6,1b and Interferon-γ (17.49 ± 1.92 pg/ml), (8.58 ± 1.15 pg/ml), and (33.33 ± 7.57 pg/ml) compared with control subjects (13.81 ± 1.71 pg/ml), (4.98 ± 0.52 pg/ml), and (22.99 ± 4.68 pg/ml), (P = 0.0001, P = 0.0001, and P = 0.0001). But the level of Interlukin-10 in keratoconus patients was significantly lower (6.07 ± 1.35 pg/ml) than controls (8.99 ± 0.70 pg/ml) (P = 0.0001). We realized that the proinflammatory markers (Interlukin-6,1-b and Interferon-γ) are over expressed, whereas the anti-inflammatory marker (Interlukin-10) is under expressed, indicating that the pathogenesis of keratoconus may involve complex chronic inflammatory events. Additional future studies will reveal the exact molecular and biochemical mechanisms that are required to better manage the disease and halt its progression.