Assessing progression limits in different grades of keratoconus from a novel perspective: precision of measurements of the corneal epithelium.

BACKGROUND: To assess repeatability and reproducibility of corneal epithelium thickness (ET) measured by a spectral-domain optical coherence tomographer (SD-OCT)/Placido topographer (MS-39, CSO, Florence, Italy) in keratoconus (KC) population at different stages, as well as to determine the progression limits for evaluating KC progression. METHODS: A total of 149 eyes were enrolled in this study, with 29 eyes in the forme fruste keratoconus (FFKC) group, 34 eyes in the mild KC group, 40 eyes in the moderate KC group, and 46 eyes in the severe KC group. Employing the within-subject standard deviation (Sw), test-retest variability (TRT), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) to evaluate intraoperator repeatability and interoperator reproducibility. RESULTS: The repeatability and reproducibility of MS-39 in patients with KC were acceptable, according to ICC values ranging from 0.732 to 0.954. However, patients with more severe KC and progressive peripheralization of the measurement points had higher TRTs but a thinning trend. The current study tended to set the cut-off values of mild KC, moderate KC, and severe KC to 4.9 µm, 5.2 µm, and 7.4 µm for thinnest epithelium thickness (TET). When differences between follow-ups are higher than those values, progression of the disease is possible. As for center epithelium thickness (CET), cut-off values for mild KC, moderate KC, and severe KC should be 2.8 µm, 4.4 µm, and 5.3 µm. This might be useful in the follow-up and diagnosis of keratoconus. CONCLUSIONS: This study demonstrated that the precision of MS-39 was reduced in measuring more severe KC patients and more peripheral corneal points. In determining disease progression, values should be differentiated between disease-related real changes and measurement inaccuracies. Due to the large difference in ET measured by MS-39 between various stages of disease progression, it is necessary to accurately grade KC patients to avoid errors in KC clinical decision-making.

Evaluation of a New All-in-One Optical Biometer and Comparison With a Validated Swept-source OCT Biometer.

PURPOSE: To assess agreement between a new all-in-one non-contact optical biometer based on optical low coherence reflectometry (SW-9000 µm Plus; Suoer) and a swept-source optical coherence tomography biometer (OA-2000; Tomey). METHODS: Each eye was scanned three times in a row by each device at random. The measured ocular parameters included central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), axial length (AL), flat keratometry (Kf), steep keratometry (Ks), mean keratometry (Km), astigmatism, corneal diameter (CD), and pupil diameter (PD). The paired t test was used to show the differences between the SW-9000 and OA-2000. Bland-Altman plots and the 95% limits of agreement (LoA) were applied to assess the consistency of the measurements. RESULTS: Sixty eyes from 60 healthy participants were examined, with a mean spherical equivalent refraction of -5.58 ± 2.31 diopters and a mean age of 30.40 ± 6.07 years. The Bland-Altman plots showed high agreement for AL, ACD, LT, Kf, Ks, Km, astigmatism, and CD measurements (95% LoA: -0.06 to 0.04 mm, -0.10 to 0.06 mm, -0.12 to 0.11 mm, -0.30 to 0.29 D, -0.35 to 0.38 D, -0.29 to 0.30 D, -0.30 to 0.34 D, and -0.50 to 0.06 mm, respectively), whereas the agreement for CCT and PD were moderate (95% LoA: 7.12 to 20.43 µm, -0.75 to 1.19 mm, respectively). CONCLUSIONS: The new all-in-one non-contact biometer had high agreement with the OA-2000 biometer on the AL, ACD, LT, Kf, Ks, Km, astigmatism, and CD measurements. For most of the ocular parameters assessed, they were clinically interchangeable. [J Refract Surg. 2023;39(12):825-830.].

Effective Optical Zone and Centration Following SMILE and FS-LASIK for High Myopia Calculated With a Novel Method.

PURPOSE: To compare the effective optical zone (EOZ) and centration in eyes with high myopia after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) using a novel method. METHODS: Forty eyes of 40 consecutive patients with high myopia scheduled for SMILE or FS-LASIK were enrolled in the study. The EOZ, optical zone decentration, and corneal aberrations were analyzed using Scheimpflug imaging. These values were then analyzed and compared between the two procedures 6 months after surgery. RESULTS: The mean EOZ diameter for SMILE (4.41 ± 0.14 mm) was larger than that for FS-LASIK (4.24 ± 0.28 mm; P = .002), corresponding to reductions of 1.60 ± 0.11 and 1.71 ± 0.21 mm, respectively, compared with the programmed optical zone (POZ) (P = .007). Moreover, the total decentration for SMILE (0.33 ± 0.12 mm) was greater than that for FS-LASIK (0.27 ± 0.15 mm; P = .020). The induction of spherical aberration (SA) was lower with SMILE than with FS-LASIK (P = .007). CONCLUSIONS: A larger EOZ and less SA were observed after SMILE than after FS-LASIK in eyes with high myopia. [J Refract Surg. 2023;39(11):736-740.].

Myeloid-derived suppressor cells ameliorate corneal alkali burn through IL-10-dependent anti-inflammatory properties.

This study aims to investigate the efficiency and the underlying mechanism of myeloid-derived suppressor cells (MDSCs) in corneal alkali burns (CAB). In the study, CD11b+ Gr-1+ cells from C57BL/6J mice bone marrow were cultured and induced. Cell activity and immunoregulatory function were assessed by flow cytometry in vitro. The optimal strategy of MDSCs therapy was assessed by slit-lamp microscopy, and flow cytometry in vivo. The therapeutic effects of MDSCs and the critical signaling pathway were investigated by hematoxylin-eosin (HE) staining, slit-lamp microscopy, flow cytometry, and immunofluorescence. The expression level of the NLRP3 inflammasome pathway was examined. The crucial biochemical parameters of MDSCs were examined by RNA-seq and qPCR to screen out the key regulators. The mechanism of MDSCs' therapeutic effects was explored using MDSCs with IL-10 knockout/rescue by slit-lamp microscopy, HE staining, and qPCR evaluation. The cell frequencies of macrophages and neutrophils in the cornea were examined by flow cytometry in vivo. The results demonstrated that the induced MDSCs meet the standard of phenotypic and functional characteristics. The treatment of 5 × 105 MDSCs conjunctival injection on alternate days significantly ameliorated the disease development, downregulated the NLRP3 inflammasome pathway, and decreased the cell frequencies of macrophages and neutrophils in vivo significantly. IL-10 was screened out to be the critical factor for MDSCs therapy. The therapeutic effects of MDSCs were impaired largely by IL-10 knock-out and saved by the IL-10 supplement. In conclusion, MDSCs therapy is a promising therapeutic solution for CAB. MDSCs fulfilled immunoregulatory roles for CAB by IL-10-dependent anti-inflammatory properties.

Mitochondrial Regulation of Ferroptosis in Cancer Therapy.

Ferroptosis, characterized by glutamate overload, glutathione depletion, and cysteine/cystine deprivation during iron- and oxidative-damage-dependent cell death, is a particular mode of regulated cell death. It is expected to effectively treat cancer through its tumor-suppressor function, as mitochondria are the intracellular energy factory and a binding site of reactive oxygen species production, closely related to ferroptosis. This review summarizes relevant research on the mechanisms of ferroptosis, highlights mitochondria's role in it, and collects and classifies the inducers of ferroptosis. A deeper understanding of the relationship between ferroptosis and mitochondrial function may provide new strategies for tumor treatment and drug development based on ferroptosis.

An IgY Effectively Prevents Goslings from Virulent GAstV Infection.

Goose astrovirus (GAstV) leads to viscera and joints urate deposition in 1- to 20-day-old goslings, with a mortality rate of up to 50%, posing a severe threat to entire colonies; however, there is no efficient prevention and control method for GAstV infection. This study describes a prophylactic anti-GAstV strategy based on the specific immunoglobulin Y (IgY) from egg yolk. The specific IgY was produced by 22-week-old laying hens intramuscularly immunized with the inactivated GAstV three consecutive times, with 2-week intervals. The egg yolk was collected weekly after the immunization and the anti-GAstV IgY titer was monitored using an agar gel immune diffusion assay (AGID). The results revealed that the AGID titer began to increase on day 7, reached a peak on day 49, and remained at a high level until day 77 after the first immunization. The specific IgY was prepared from the combinations of egg yolk from day 49 to day 77 through PEG-6000 precipitation. Animal experiments were conducted to evaluate the effects of prevention and treatment. The result of the minimum prophylactic dose of the IgY showed that the protection rate was 90.9% when 2.5 mg was administrated. Results of the prevention and the treatment experiments showed prevention and cure rates of over 80% when yolk antibody was administered in the early stages of the GAstV infection. These results suggested that the specific IgY obtained from immunized hens with the inactivated GAstV could be a novel strategy for preventing and treating GAstV infection.

Developing a new treatment for superficial fungal infection using antifungal Collagen-HSAF dressing.

Fungal pathogens are common causes of superficial clinical infection. Their increasing drug resistance gradually makes existing antifungal drugs ineffective. Heat stable antifungal factor (HSAF) is a novel antifungal natural product with a unique structure. However, the application of HSAF has been hampered by very low yield in the current microbial producers and from extremely poor solubility in water and common solvents. In this study, we developed an effective mode of treatment applying HSAF to superficial fungal infections. The marine-derived Lysobacter enzymogenes YC36 contains the HSAF biosynthetic gene cluster, which we activated by the interspecific signaling molecule indole. An efficient extraction strategy was used to significantly improve the purity to 95.3%. Scanning electron microscopy images revealed that the Type I collagen-based HSAF (Col-HSAF) has a transparent appearance and good physical properties, and the in vitro sustained-release effect of HSAF was maintained for more than 2 weeks. The effective therapeutic concentration of Col-HSAF against superficial fungal infection was explored, and Col-HSAF showed good biocompatibility, lower clinical scores, mild histological changes, and antifungal capabilities in animals with Aspergillus fumigatus keratitis and cutaneous candidiasis. In conclusion, Col-HSAF is an antifungal reagent with significant clinical value in the treatment of superficial fungal infections.

Galectin-3 Is a Crucial Immunological Disease Marker in Patients with Fungal Keratitis.

Fungal keratitis, one of the most common infectious eye diseases in China, often results in a poor prognosis due to a delayed diagnosis and the insufficiency of effective therapy. There is an urgent need to identify specific biomarkers for the disease. In this study, we screened out tear proteins in patients with fungal keratitis by microsphere-based immunoassay analysis. Levels of cytokine expression were determined in both human corneal epithelial cell models in vitro and the corneas of patients by western blot, quantitative polymerase chain reaction (qPCR), and immunofluorescence analysis. Neutrophil activation was examined by flow cytometry analysis. The relationship between the cytokine expression and neutrophils was evaluated by immunofluorescence costaining and correlation analysis. These results demonstrated that the galectin-3 expression level was increased in both cell model and patient samples at the early and late stages of fungal keratitis. The neutrophils were significantly activated during the disease course of fungal keratitis. Meanwhile, colocalization and a positive correlation between galectin-3 and neutrophils were observed, suggesting that galectin-3 may play a crucial role in the recruitment of neutrophils and immune regulation of fungal keratitis. In conclusion, galectin-3 could be a key disease marker implying a beneficial immune response in the pathogenesis of fungal keratitis, which might be a target of therapeutic strategy in the future.

Inhibition of Galectin-3 Impairs Antifungal Immune Response in Fungal Keratitis.

Galectin-3 is one of the galectin family members which are master regulators of immune homeostasis, especially in infectious diseases. However, its mechanism of immune regulation in fungal keratitis has not been thoroughly studied. Our study is aimed at clarifying the role of galectin-3 in the fungal keratitis mouse model in vivo, thereby providing a new biomarker of antifungal therapy. In our study, aspergillus, the most common pathogenic fungi of fungal keratitis, was identified and isolated by corneal tissue fungus culture. Then, the RNA expression levels of galectin family members in corneas of the mouse model with aspergillus fumigatus keratitis were screened by transcriptome sequencing (RNA-seq). The expression of the galectin-3 was detected by quantitative real-time Polymerase Chain Reaction (qPCR), enzyme-linked immunosorbent assay (ELISA), and immunofluorescence in the corneal tissue of the fungal keratitis mouse model. Recruitment of neutrophils and the co-immunofluorescence of galectin-3 and related markers in corneal tissue were determined by flow cytometry analysis and immunofluorescence staining. The regulatory role of galectin-3 for proinflammatory cytokines and neutrophils was validated by the knockout mouse model. Galectin-3 knockout deteriorated the condition for the inhibition of galectin-3 was benefecial for fungi to survive and thrive in corneal lesions. These results demonstrated that in the ocular fungal infection, galectin-3 is capable of regulating the pathogenesis of fungal keratitis by modulating neutrophil recruitment. The deterioration of fungal keratitis and increased fungal load in corneal lesions of galectin-3 knockout mice proved the regulatory role of galectin-3 in fungal keratitis. In conclusion, galectin-3 is going to be an essential target to modulate neutrophil recruitment and its related antifungal immune response in fungal keratitis.

Melatonin ameliorates oxidative stress-mediated injuries through induction of HO-1 and restores autophagic flux in dry eye.

This study aimed to investigate the protective effect of melatonin on the corneal epithelium in dry eye disease(DED) and explore its underlying mechanism. Human corneal epithelial(HCE) cells was exposure to t-butylhydroperoxide(tBH), C57BL/6 mice were injected of subcutaneous scopolamine to imitate DED. Melatonin was used both in vivo and in vitro. Cell viability was detected by Cell Counting Kit-8 assay and Lactate Dehydrogenase Leakage. The change of cellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and apoptosis was analyzed by flow cytometry. Western blot assays and immunofluorescence were carried out to measure protein changes. mRNA expression was investigated by RNA sequencing (RNA-Seq) and quantitative real-time PCR. The change of autophagic flux were observed through mCherry-GFP-LC3 transfection and electron microscopy(TEM). Clinical parameters of corneal epithelium defects, conjunctival goblet cells, tear volume, and level of ocular surface inflammation was recorded. Melatonin was able to reduce excessive ROS production and maintain mitochondrial function. TEM assay found melatonin rescued impaired autophagic flux under tBH. Moreover, melatonin significantly preserved cell viability, abolished LDH release, and decreased apoptosis. RNA-Seq indicated that melatonin greatly activating hemeoxygenase-1 (HO-1) expression. Interestingly, HO-1 ablation largely attenuated its protective effects. Besides, in dry eye mouse model, intraperitoneal injection of melatonin showed greatly improved clinical parameters, inhibited activated NLRP3 inflammation cascade, and increased density of goblet cells and tear volume. Thus, melatonin protects corneal epithelial cells from oxidative damage, maintain normal level of autophagy, and reduce inflammation via trigging HO-1 expression in DED.

Heparin-Modified Amniotic Membrane Combined With Growth Factors for Promoting Corneal Wound Healing After Alkali Burn.

Ocular chemical burns are potentially blinding ocular injuries and require urgent management. Amniotic membrane (AM) transplantation is an effective surgical treatment, one of the reasons is because AM is a rich source of growth factors that can promote epithelialization and wound healing. However, growth factors will be gradually lost and insufficient after preparation process and long-time storage, leading to unsatisfactory therapeutic effects. Herein, we present a modified AM (AM-HEP) for the supplement and sustained release of growth factor by surface grafting heparin for treatment of ocular chemical burns. Heparin grafting rate and stability, microstructure, physical property, and sustained release of epithelial growth factor (EGF) of AM-HEP were characterized. Biocompatibility and ability to promote corneal epithelial cell growth and migration were evaluated and compared with a biological amnion, which is available on the market in vitro. The therapeutic effects of AM-HEP combined with EGF (AM-HEP@EGF) in vivo had been evaluated in a model of mouse corneal alkali burn. The results indicated that heparin was introduced into AM and maintain stability over 3 weeks at 37°C. The modification process of AM-HEP did not affect microstructure and physical property after comparing with non-modified AM. EGF could be combined quickly and effectively with AM-HEP; the sustained release could last for more than 14 days. AM-HEP@EGF could significantly promote corneal epithelial cell growth and migration, compared with non-modified AM and control group. Faster corneal epithelialization was observed with the transplantation of AM-HEP@EGF in vivo, compared with the untreated control group. The corneas in the AM-HEP@EGF group have less inflammation and were more transparent than those in the control group. The results from in vitro and in vivo experiments demonstrated that AM-HEP@EGF could significantly enhance the therapeutic effects. Taken together, AM-HEP@EGF is exhibited to be a potent clinical application in corneal alkali burns through accelerating corneal epithelial wound healing.

Therapeutic effects of an anti-IL-6 antibody in fungal keratitis: Macrophage inhibition and T cell subset regulation.

Immune modulation plays a critical role in the pathogenesis of fungal keratitis (FK). However, the immune cell-mediated processes linking the innate immune response to the adaptive immune response are incompletely elucidated. IL-6 plays crucial roles in infectious and inflammatory processes in the cornea, regulating not only mononuclear macrophage differentiation but also lymphocyte activation, and IL-6 might be a useful target for immune intervention in FK. The frequencies of macrophages and T cells increased upon infection and were correlated with the severity of ocular pathogenesis. Additionally, protein profiling revealed that the expression of IL-6 and associated cytokines/chemokines was upregulated. Furthermore, anti-IL-6 intervention suppressed disease progression by reducing macrophage infiltration in the cornea and Th1, Th17, and Treg cell infiltration in draining lymph nodes (DLN) in an animal model of FK. Tocilizumab (TCZ), an antibody specific for IL-6, reduced the signal transducer and activator of transcription 3 (STAT3) activation in vivo and in vitro. In summary, fungal infection promoted macrophage and T cell activation via IL-6-mediated transcellular signaling to regulate immune cell migration and cytokine production, further demonstrating the role of IL-6 and providing a potential clinical therapeutic target in FK.

D609 protects retinal pigmented epithelium as a potential therapy for age-related macular degeneration.

Accumulated oxidative damage may lead to irreversible retinal pigmented epithelium (RPE) cell death, which is considered to be the primary cause of dry age-related macular degeneration (AMD), leading to blindness in the elderly. However, an effective therapy for this disease is lacking. Here, we described a robust high-content screening procedure with a library of 814 protective compounds and found that D609 strongly protected RPE cells from sodium iodate (SI)-induced oxidative cell death and prolonged their healthy survival. D609 effectively attenuated excessive reactive oxygen species (ROS) and prevented severe mitochondrial loss due to oxidative stress in the RPE cells. Surprisingly, the potent antioxidative effects of D609 were not achieved through its own reducibility but were primarily dependent on its ability to increase the expression of metallothionein. The injection of this small water-soluble molecule also showed an explicit protective effect of the RPE layer in an SI-induced AMD mouse model. These findings suggested that D609 could serve as a novel antioxidative protector of RPE cells both in vitro and in vivo and unveiled a novel antioxidative mechanism of D609, which may ultimately have clinical applications for the treatment of AMD.

Identification of Potential Gene Signatures Related to Sleep Deprivation.

This study aimed to identify possible therapeutic targets involved in sleep deprivation (SD) risks. GSE77393 data set was acquired from Gene Expression Omnibus database. Functional analysis and protein-protein interaction (PPI) analysis were used to extract the differentially expressed genes (DEGs) between two SD samples and control samples. Moreover, submodule network with the same function was further extracted and the functional enrichment analysis of corresponding genes was carried out. Afterward, the transcriptional regulation analysis and drug-gene interaction were also carried out to identify the essential genes associated with SD susceptibility. Totally, 121 DEGs, including 90 consistently upregulated DEGs and 31 downregulated DEGs, were screened and the results of functional analysis indicated that upregulated genes were related to learning or memory and response to drug, whereas downregulated DEGs were mainly responsible for response to UV and cell differentiation. Moreover, PPI network and submodule analysis revealed that many key genes (FOS and BDNF) were hub genes and the KEGG enrichment analysis found that these genes such as FOS and BDNF were considerably enriched in pathways such as MAPK signaling pathway, HTLV-I infection, and Hepatitis B. In addition, two genes (FOS and BDNF) with a higher degree were found to be key regulators and play important roles in the transcriptional regulator network and drug-gene interactions, suggesting that these two genes were associated with SD development. FOS and BDNF might be served as the potential targets for SD treatment.

Induction of DDIT4 Impairs Autophagy Through Oxidative Stress in Dry Eye.

Purpose: To assess how DNA damage-inducible transcript 4 (DDIT4) and autophagic flux are altered in dry eye disease and reveal the underlying mechanisms. Methods: C57BL/6 mice were exposed to desiccating stress (subcutaneous scopolamine [0.5 mg/0.2 mL] 3 times a day, humidity < 30%) for 7 days. Primary human corneal epithelial cells and cells from a human corneal epithelial cell line were cultured under hyperosmolarity. Western blot assays and immunofluorescence staining were used to measure changes in protein expression. mRNA expression was analyzed by RT-PCR and quantitative real-time PCR. Autophagosomes were observed through electron microscopy. Cellular reactive oxygen species and mitochondrial function were detected with 2',7'-dichlorodihydrofluorescein diacetate and mitochondrial membrane potential assays. Cell Counting Kit-8 and lactate dehydrogenase assays were used to measure cell death. Apoptosis was analyzed by Annexin V-PI flow cytometry. Results: Increased expression of microtubule-associated protein 1 light chain 3 (LC3-II), sequestosome 1 (SQSTM1), and DDIT4 were observed in corneal epithelial cells in in vitro and mice models of dry eye. The electron microscopy revealed large autophagic vacuoles with poorly degraded materials in human corneal epithelial cells under hyperosmolarity. In addition, we found that DDIT4 knockdown significantly suppressed the expression of LC3-II and SQSTM1 by disrupting reactive oxygen species release and restoring mitochondrial function under hyperosmolarity. Moreover, the ablation of DDIT4 effectively preserved cell viability and inhibited apoptosis. Conclusions: Excessive reactive oxygen species release through DDIT4 induction can lead to impaired autophagy and decreased cell viability in dry eye disease.

The role of the IL-33/ST2 axis in autoimmune disorders: Friend or foe?

Autoimmune diseases (ADs), which are common immune-mediated inflammatory syndromes, are characterized by an imbalance between T effector (Th)1/Th17 cells and T regulatory cells. Interleukin (IL)-33, a member of the IL-1 family, induces inflammatory disease development by mediating type 2 immune responses. Recently, IL-33/ST2 axis was reported to induce autoimmunity involving Th1 and Th17 cells. In this review, we focus on the expression, regulation and function of IL-33/ST2 pathway in the context of autoimmune disorders. We discuss the clinical potential of this signaling pathway in predicting disease activity and severity and offer possible future therapeutic alternatives.

Risk factors influencing survival of acellular porcine corneal stroma in infectious keratitis: a prospective clinical study.

BACKGROUND: A worldwide lack of donor corneas demands the bioengineered corneas be developed as an alternative. The primary objective of the current study was to evaluate the efficacy of acellular porcine corneal stroma (APCS) transplantation in various types of infectious keratitis and identify risk factors that may increase APCS graft failure. METHODS: In this prospective interventional study, 39 patients with progressive infectious keratitis underwent therapeutic lamellar keratoplasty using APCS and were followed up for 12 months. Data collected for analysis included preoperative characteristics, visual acuity, graft survival and complications. Graft survival was evaluated by the Kaplan-Meier method and compared with the log-rank test. RESULTS: The percentage of eyes that had a visual acuity of 20/40 or better increased from 10.3% preoperatively to 51.2% at 12 months postoperatively. Twelve patients (30.8%) experienced graft failure within the follow-up period. The primary reasons given for graft failure was noninfectious graft melting (n = 5), and the other causes included recurrence of primary infection (n = 4) and extensive graft neovascularization (n = 3). No graft rejection was observed during the follow-up period. A higher relative risk (RR) of graft failure was associated with herpetic keratitis (RR = 8.0, P = 0.046) and graft size larger than 8 mm (RR = 6.5, P < 0.001). CONCLUSIONS: APCS transplantation is an alternative treatment option for eyes with medically unresponsive infectious keratitis. Despite the efficacy of therapeutic lamellar keratoplasty with APCS, to achieve a good prognosis, restriction of surgical indications, careful selection of patients and postoperative management must be emphasized. Trial registration Prospective Study of Deep Anterior Lamellar Keratoplasty Using Acellular Porcine Cornea, NCT03105466. Registered 31 August 2016, ClinicalTrails.gov.

Hemin Promotes Corneal Allograft Survival Through the Suppression of Macrophage Recruitment and Activation.

Purpose: To explore the roles of hemin in preventing corneal allograft rejection (CGR) and the underlying mechanisms. Methods: Hemin (30 mg/kg) was intraperitoneally injected into rats with a corneal allograft on alternate days, from the day of transplantation until euthanasia. The clinical signs of the corneal allografts were evaluated and recorded according to a previously published system. Corneal edema, macrophage infiltration, and phenotype, and the expression of chemokines, cytokines, and heme oxygenase (HO)-1 were detected by histology, real-time PCR, and Western blot. The rat macrophage cell line NR8383 was used to explore the mechanisms of action of hemin in vitro. Results: Treatment with hemin significantly prolonged corneal allograft survival, with decreased corneal edema and fewer macrophages. Moreover, hemin treatment alleviated inflammation in the corneal grafts, as characterized by downregulated mRNA levels of proinflammatory mediators. In addition, hemin administration reduced the proportion of proinflammatory M1 macrophages and increased the proportion of anti-inflammatory M2 macrophages in the corneal grafts. Hemin treatment induced HO-1 expression in vivo and in vitro, whereas co-administration of zinc protoporphyrin IX (ZnPP), an HO-1 inhibitor, blocked the beneficial effects of hemin in preventing CGR. Conclusions: Our results are the first to demonstrate that hemin, a Food and Drug Administration-approved drug, promotes corneal allograft survival. These findings indicate that hemin might be a potential alternative treatment for CGR.

NLRP3 inflammasome: A likely target for the treatment of allergic diseases.

Allergic diseases, such as asthma, rhinitis, dermatitis, conjunctivitis, and anaphylaxis, have recently become a global public health concern. According to previous studies, the NLRP3 inflammasome is a multi-protein complex known to be associated with many inflammatory conditions. In response to allergens or allergen/damage-associated molecular signals, NLRP3 changes its conformation to allow the assembly of the NLRP3 inflammasome complex and activates caspase-1, which is an evolutionarily conserved enzyme that proteolytically cleaves other proteins, such as the precursors of the inflammatory cytokines IL-1ß and IL-18. Subsequently, active caspase-1 cleaves pro-IL-1 and pro-IL-18. Recently, accumulating human and mouse experimental evidence has demonstrated that the NLRP3 inflammasome, IL-1ß, and IL-18 are critically involved in the development of allergic diseases. Furthermore, the application of specific NLRP3 inflammasome inhibitors has been demonstrated in animal models. Therefore, these inhibitors may represent potential therapeutic methods for the management of clinical allergic disorders. This review summarizes findings related to the NLRP3 inflammasome and its related factors and concludes that specific NLRP3 inflammasome inhibitors may be potential therapeutic agents for allergic diseases.

Baicalin modulates the Treg/Teff balance to alleviate uveitis by activating the aryl hydrocarbon receptor.

Autoimmune uveitis is a sight-threatening ocular inflammatory disorder. Immunological inflammation is regarded as the key to pathogenesis in autoimmune uveitis. Baicalin, the major bioactive component of Scutellaria baicalensis, possesses immunomodulatory properties. However, the role of baicalin in uveitis and its underlying mechanisms remain unclear. In the current study, we found that baicalin treatment obviously inhibited the intraocular inflammatory process in mice with experimental autoimmune uveitis, along with clear declines in infiltrated inflammatory cells and inflammatory cytokine transcription in the retina and draining lymph nodes. Furthermore, baicalin treatment increased the frequency and number of regulatory T cells and decreased the frequency and number of effector T cells (Th1 and Th17 cells) in the draining lymph nodes of mice with experimental autoimmune uveitis. In vitro, baicalin treatment suppressed interphotoreceptor retinoid binding protein-specific CD4+ T cell proliferation and converted CD4+ T cell differentiation. Furthermore, the expression of aryl hydrocarbon receptor was activated by baicalin treatment. Baicalin-mediated modulation of CD4+ T cell differentiation was partially abrogated by the suppression of aryl hydrocarbon receptor. These findings suggest that baicalin modulates the Treg/Teff balance and CD4+ T cell proliferation to ameliorate experimental autoimmune uveitis by activating the aryl hydrocarbon receptor.