Significantly different results in the ocular surface microbiome detected by tear paper and conjunctival swab.

BACKGROUND: Great variation has been observed in the composition of the normal microbiota of the ocular surface, and therefore, in addition to differences in detection techniques, the method of collecting ocular surface specimens has a significant impact on the test results.The goal of this study is to ascertain whether the eye surface microbial communities detected by two different sampling methods are consistent and hence explore the feasibility of using tear test paper instead of conjunctival swabs to collect eye surface samples for microbial investigation. MATERIALS AND METHODS: From July 15, 2021, to July 30, 2021, nonirritating tear test strips and conjunctival swabs of both eyes were used in 158 elderly people (> 60 years old) (79 diabetic and 79 nondiabetic adults) in Xinjing Community for high-throughput sequencing of the V3-V4 region of the 16S rRNA gene. The composition of the microbial communities in tear test paper and conjunctival swab samples was analyzed. RESULTS: There was no statistically significant difference in Alpha diversity of ocular surface microorganisms represented by tear strip and conjunctival swab in diabetic group (P > 0.05), but there was statistically significant difference in Alpha diversity of ocular surface microorganisms detected by tear strip and conjunctival swab in nondiabetic group (P < 0.05). There were statistically significant differences in Beta diversity of ocular surface microorganisms detected by two sampling methods between diabetic group and nondiabetic group (P < 0.05). There were statistically significant differences in ocular surface microorganisms detected by tear strip method between diabetic group and nondiabetic group (P < 0.05), but there was no statistically significant difference in conjunctival swab method (P > 0.05). CONCLUSIONS: Tear test paper and conjunctival swabs detect different compositions of microbes through two different techniques of eye surface microbe sampling. Tear test paper cannot completely replace conjunctival swab specimens for the study of microbes related to eye surface diseases.

A novel peptide derived from the mannose binding lectin inhibits LPS-activated TLR4/NF-κB signaling and suppresses ocular inflammation.

Uveitis is a major cause of vision impairment worldwide. Current treatments have limited effectiveness but severe complications. Mannose binding lectin (MBL) is an important protein of the innate immune system that binds to TLR4 and suppresses LPS-induced inflammatory cytokine secretion. MBL-mediated inhibition of inflammation via the TLR4 pathway and MBL-derived peptides might be a potential therapeutics. In this study, we designed a novel MBL-derived peptide, WP-17, targeting TLR4. Bioinformatics analysis was conducted for the sequence, structure and biological properties of WP-17. The binding of WP-17 to THP-1 cells was analyzed using flow cytometry. Signaling molecules were analyzed by western blotting, and activation of NF-κB was measured by immunofluorescence-histochemical analysis. Effects of WP-17 were studied in vitro using LPS-stimulated THP-1 cells and in vivo in endotoxin-induced uveitis (EIU). Our results showed that WP-17 could bind to TLR4 expressed on macrophages, thus downregulating the expression levels of MyD88, IRAK-4, and TRAF-6, and inhibiting the downstream NF-kB signaling pathway and LPS-induced expression of TNF-α and IL-6 in THP-1 cells. Moreover, in EIU rats, intravitreal pretreatment with WP-17 demonstrated significant inhibitory effects on ocular inflammation, attenuating the clinical and histopathological manifestations of uveitis, reducing protein leakage and cell infiltration into the aqueous humor, and suppressing TNF-α and IL-6 production in ocular tissues. In summary, our study provides the first evidence of a novel MBL-derived peptide that suppressed activation of the NF-кB pathway by targeting TLR4. The peptide effectively inhibited rat uveitis and may be a promising candidate for the management of ocular inflammatory diseases.

Endomucin restores depleted endothelial glycocalyx in the retinas of streptozotocin-induced diabetic rats.

Endothelial glycocalyx plays a significant role in the development and progression of diabetic complications. Endomucin (EMCN) is an anti-inflammatory membrane glycoprotein that is mainly expressed in venous and capillary endothelial cells. However, the function of EMCN in diabetic retinopathy (DR) progression is still completely unknown. We first investigated the change of EMCN expression in the retina and human retinal microvascular endothelial cells. We then overexpressed EMCN in the retina with adeno-associated virus and induced DR with streptozotocin (STZ). We analyzed EMCN's effect on the integrity of endothelial glycocalyx under conditions of DR. Furthermore, we investigated EMCN's protective effect against inflammation and blood-retinal barrier (BRB) destruction. We found that EMCN is specifically expressed in retinal endothelial cells and that its levels are decreased during hyperglycemia in vitro and in vivo. Overexpression of EMCN can restore the retinal endothelial glycocalyx of STZ-induced diabetic rats. Furthermore, EMCN overexpression can decrease leukocyte-endothelial adhesion to ameliorate inflammation and stabilize the BRB to inhibit vessel leakage in rats with DR. EMCN may protect patients with diabetes from retinal vascular degeneration by restoring the endothelial glycocalyx. EMCN may thus represent a novel therapeutic strategy for DR because it targets endothelial glycocalyx degradation associated with this disease.-Niu, T., Zhao, M., Jiang, Y., Xing, X., Shi, X., Cheng, L., Jin, H., Liu, K. Endomucin restores depleted endothelial glycocalyx in the retinas of streptozotocin-induced diabetic rats.

KS23, a novel peptide derived from adiponectin, inhibits retinal inflammation and downregulates the proportions of Th1 and Th17 cells during experimental autoimmune uveitis.

BACKGROUND: Uveitis is a potentially sight-threatening form of ocular inflammation that affects the uvea in the wall of the eye. Currently available treatments for uveitis have exhibited profound adverse side effects. However, KS23 is a novel 23-amino-acid anti-inflammatory peptide derived from adiponectin that may have the capability to function as a safe alternative to these existing treatment options. We, therefore, evaluated the preventive effect of KS23 in experimental autoimmune uveitis (EAU). METHODS: EAU was induced in mice via immunization with the peptide interphotoreceptor retinoid binding protein 161-180 (IRBP161-180). KS23 was then administered every 2 days via intraperitoneal injection to induce protection against EAU. Clinical and histopathological scores were employed to evaluate the disease progression. Inflammatory cytokines were also quantified using ELISA, and the expression levels of specific chemokines and chemokine receptors were assessed via qRT-PCR. In addition, the proportions of Th1 and Th17 cells were detected via flow cytometry, and the expression levels of specific proteins were quantified from the retina of mice using western blot analysis, to elucidate the specific mechanism of action employed by KS23 to suppress the inflammation associated with EAU. RESULTS: KS23 was found to significantly improve EAU-associated histopathological scores, while decreasing the expression of pro-inflammatory cytokines (IFN-γ, TNF-α, IL-6, and IL-17A), chemokines (LARC, RANTES, MIG, IP-10), and chemokine receptors (CCR6 and CXCR3). The proportions of Th1 and Th17 cells were also suppressed following intraperitoneal injection with KS23. The anti-inflammatory mechanism employed by KS23 was determined to be associated with the activation of AMPK and subsequent inhibition of NF-κB. CONCLUSIONS: KS23 decreased the proportions of Th1 and Th17 cells to effectively ameliorate the progression of EAU. It may, therefore, serve as a promising potential therapeutic agent for uveitis.

Peptide GC31 inhibits chemokines and ICAM-1 expression in corneal fibroblasts exposed to LPS or poly(I:C) by blocking the NF-κB and MAPK pathways.

In keratitis, keratocytes play a vital role by releasing inflammatory cytokines and expressing intercellular cell adhesion molecule-1(ICAM-1). GC31 is a peptide derived from thrombomodulin, an endogenous protein with potential anti-inflammation properties. We evaluated the protective effect of GC31 in LPS- or poly(I:C)-induced corneal fibroblasts. Cultured keratocytes were treated with either LPS or poly(I:C); The mRNA and protein expressions of IL-6, IL-8, MCP-1, and IFN-γ were determined by real-time RT-PCR and ELISA. The expression level of ICAM-1 was estimated by real-time RT-PCR, immunofluorescence, and western blot. The underlying pathways were investigated by detecting NF-κB p65 translocation and phosphorylation of IκBα, p65, p38, JNK, and ERK. The MTS assay was used to measure cell viability of keratocytes after GC31 incubation. The elevation of IL-6, IL-8, MCP-1, and IFN-γ expression induced by LPS or poly(I:C) was significantly inhibited by GC31 in a dose-dependent manner at both mRNA and protein levels. GC31 also reduced the expression of ICAM-1 in keratocytes after LPS or poly(I:C) stimulation. LPS or poly(I:C) induced p65 translocation and phosphorylation of IκBα, p65, p38, and JNK were suppressed by GC31.GC31 is not only an effective inhibitor of LPS-induced inflammatory response, but it also inhibits poly(I:C)-induced release of inflammatory cytokines and ICAM-1 expression by blocking the NF-κB and MAPK (p38 and JNK) pathways. This suggested that GC31 may exert a protective effect in attenuating corneal inflammation by suppressing the immune response of the fibroblasts.

Effects of a thrombomodulin-derived peptide on monocyte adhesion and intercellular adhesion molecule-1 expression in lipopolysaccharide-induced endothelial cells.

PURPOSE: It has been documented that GC31, a 31-animo acid peptide from human thrombomodulin, has potent anti-inflammatory properties in endotoxin-induced uveitis and lipopolysaccharide (LPS)-induced RAW264.7 cells, while the role of GC31 in the endothelial cells has not yet been fully understood. Therefore, the aim of this study was to explore the effect of GC31 on intercellular adhesion molecule-1 (ICAM-1) expression in LPS-activated endothelial cells. METHODS: Human umbilical vein endothelial cells (HUVECs) were incubated with LPS (1 µg/ml) and peptide GC31 or control peptide VP30 simultaneously. ICAM-1 messenger RNA and protein levels were evaluated with real-time PCR and western blot. The adhesion of U937 cells labeled with CM-H2DCFDA to HUVECs was examined with fluorescence microscope. Extracellular signal-regulated kinase-1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) activation, inhibitor of nuclear factor kappa B alpha (IκBα) degradation, and nuclear factor kappa B (NF-κB) nuclear translocation were detected with western blot. RESULTS: Upon LPS stimulation, GC31 suppressed the mRNA and protein expression of ICAM-1 in HUVECs and remarkably reduced monocyte-endothelial cell adhesion in a dose-dependent manner. Furthermore, GC31 significantly inhibited the degradation of IκBα and nuclear translocation of NF-κB and moderately blocked the activation of p38 MAPK and ERK1/2 in activated HUVECs. CONCLUSIONS: Our results suggested that GC31 suppressed LPS-mediated ICAM-1 expression by inhibiting the activation of NF-κB and partially by attenuating the activity of ERK1/2 and p38 MAPK in vascular endothelium, which may contribute to ameliorating vascular inflammatory diseases, such as uveitis.

[Relationship between macular morphology and visual function in diabetic macular edema].

OBJECTIVE: To investigate the changes and relation between macular morphology and macular visual function in different degrees of diabetic macular edema. METHODS: Seventy-eight eyes of 41 diabetic retinopathy patients were included and graded for diabetic macular edema as follows:31 were graded as no macular edema (NE), 26 as non-clinically significant macular edema (NCSME), and 21 as clinically significant macular edema (CSME). Best corrected visual acuity, macular sensitivity, and macular thickness of all included eyes were examed and quantified. Macular sensitivity and retinal fixation were investigated with MP-1 microperimetry. Optical coherence tomography (OCT) was used to quantify macular thickness. RESULTS: Macular thickness significantly increased and macular sensitivity markedly decreased from the NE to the CSME group (P < 0.01), Visual acuity obviously decreased in the CSME group (P < 0.01) compared to the NE and NCSME group, but there was no statistical difference between the NE group and NCSME group. Retinal fixation type was not significantly different among three groups. Visual acuity and macular sensitivity correlated significantly in these three groups (r = -0.751, P < 0.01; r = -0.583, P < 0.01; r = -0.679, P < 0.01). The correlations were noted between retinal sensitivity and macular thickness as well as between visual acuity and macular thickness in the CSME group (r = -0.465, P < 0.05; r = 0.599, P < 0.01), but not in the NE group or in the NCSME group. CONCLUSIONS: Patients will have retinal morphologic and functional changes in early stage of DME, both of which are significantly related as the disease develops. MP-1 microperimetry proved to be consistent with VA in the evaluation of visual function, and may be more sensitive to investigate the changes of macular visual function in the early stage of macular edema.

Combination of iris vessel area density and surgery interval as the predictor of perceived pain during consecutive second-eye cataract surgery.

PURPOSE: To explore clinical indicators to predict perceived pain during second-eye phacoemulsification surgery in patients with bilateral cataracts. SETTING: Shanghai General Hospital, China. DESIGN: A case‒control study and a prospective cohort study. METHODS: Patients with age-related cataract who underwent first-eye or second-eye uneventful phacoemulsification surgery were enrolled. Before surgery, ocular examination results, including vessel area density (VAD) and vessel skeleton density (VSD), obtained by optical coherence tomography angiography examination of the iris were performed. Patients completed a visual analog scale pain survey 3 times postoperatively: 1 hour, 3 hours, and 24 hours postoperatively. RESULTS: 70 patients were enrolled in the case‒control study, and the pain scores of the second-eye surgery group under local anesthesia were significantly greater than those of the first-eye surgery group ( P = .0005). Preoperative iris VAD in the second-eye group affected perioperative pain scores ( P = .0047). The optimal cutoff value of VAD was 0.2167 with a specificity of 76% and a sensitivity of 62%. In the prospective cohort study, 124 patients were included in the second-eye group. Preoperative iris VAD ( P = .0361) and the time interval ( P = .0221) were independent factors for second-eye surgery pain. Combined with preoperative iris VAD and surgical interval, the negative predictive value and positive predictive value were 0.95 and 0.29 for predicting moderate pain or above, the sensitivity and specificity were 0.97 and 0.23, respectively. CONCLUSIONS: The combination of iris VAD and the time interval between both eye surgeries can be an effective method to predict the timing of the second-eye cataract surgery and to avoid intraoperative pain.

Hematogenous Macrophages Contribute to Fibrotic Scar Formation After Optic Nerve Crush.

Although glial scar formation has been extensively studied after optic nerve injury, the existence and characteristics of traumatic optic nerve fibrotic scar formation have not been previously characterized. Recent evidence suggests infiltrating macrophages are involved in pathological processes after optic nerve crush (ONC), but their role in fibrotic scar formation is unknown. Using wild-type and transgenic mouse models with optic nerve crush injury, we show that macrophages infiltrate and associate with fibroblasts in the traumatic optic nerve lesion fibrotic scar. We dissected the role of hematogenous and resident macrophages, labeled with Dil liposomes intravenously administered, and observed that hematogenous macrophages (Dil+ cells) specifically accumulate in the center of traumatic fibrotic scar while Iba-1+ cells reside predominantly at the margins of optic nerve fibrotic scar. Depletion of hematogenous macrophages results in reduced fibroblast density and decreased extracellular matrix deposition within the fibrotic scar area following ONC. However, retinal ganglion cell degeneration and function loss after optic nerve crush remain unaffected after hematogenous macrophage depletion. We present new and previously not characterized evidence that hematogenous macrophages are selectively recruited into the fibrotic core of the optic nerve crush site and critical for this fibrotic scar formation.

Reactive Fibroblasts in Response to Optic Nerve Crush Injury.

Traumatic optic neuropathy leads to bidirectional degeneration of retinal ganglion cells and axons and results in optic nerve scaring, which inhibits the regeneration of damaged axons. Compared with its glial counterpart, the fibrotic response causing nerve scar tissue is poorly permissive to axonal regeneration. Using collagen1α1-GFP reporter mice, we characterize the development of fibrotic scar formation following optic nerve crush injury. We observe that perivascular collagen1α1 cells constitute a major cellular component of the fibrotic scar. We demonstrate that extracellular molecules and monocytes are key factors contributing to the pathogenesis of optic nerve fibrotic scar formation, with a previously unrecognized encapsulation of this scar. We also characterize the distribution of collagen1α1 cells in the retina after optic nerve crush injury based on in vivo and whole-mount retinal imaging. Our results identify collagen1α1 cells as a major component of fibrotic scarring following ONC and are a potential molecular target for promoting axonal regeneration after optic nerve injury.

The Anti-Inflammatory Effect of KS23, A Novel Peptide Derived From Globular Adiponectin, on Endotoxin-Induced Uveitis in Rats.

Purpose: Adiponectin has been shown to exert potent anti-inflammatory activities in a range of systemic inflammatory diseases. This study aimed to investigate the potential therapeutic effects of KS23, a globular adiponectin-derived peptide, on endotoxin-induced uveitis (EIU) in rats and lipopolysaccharide (LPS)-stimulated mouse macrophage-like RAW 264.7 cells. Methods: EIU was induced in Lewis rats by subcutaneous injection of LPS into a single footpad. KS23 or phosphate-buffered saline (PBS) was administered immediately after LPS induction via intravitreal injection. Twenty-four hours later, clinical and histopathological scores were evaluated, and the aqueous humor (AqH) was collected to determine the infiltrating cells, protein concentration, and levels of inflammatory cytokines. In vitro, cultured RAW 264.7 cells were stimulated with LPS in the presence or absence of KS23, inflammatory cytokine levels in the supernatant, nuclear translocation of nuclear factor kappa B (NF-κB) subunit p65, and the expression of NF-kB signaling pathway components were analyzed. Results: KS23 treatment significantly ameliorated the clinical and histopathological scores of EIU rats and reduced the levels of infiltration cells, protein, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the aqueous humor. Consistently, KS23 decreased the expression of TNF-α and IL-6 in the supernatant of LPS-stimulated RAW 264.7 cells and inhibited the LPS-induced nuclear translocation of NF-κB p65 and the phosphorylation of IKKα/ß/IκBα/NF-κB. Conclusion: The in vivo and in vitro results demonstrated the anti-inflammatory effects of the peptide KS23 and suggested that KS23 is a compelling, novel therapeutic candidate for the treatment of ocular inflammation.

Metabolic characterization of diabetic retinopathy: An 1H-NMR-based metabolomic approach using human aqueous humor.

Patients with a long duration of diabetes mellitus (DM) usually have accompanied complications such as diabetic retinopathy (DR), which is a leading cause of blindness and visual impairment among working-age persons in developed countries; nevertheless, some patients have no complications. Thus, various studies, including genomic, transcriptomic, and proteomic studies, have been conducted to identify potential biomarkers for predicting DR and to reveal the underlying disease mechanism. Although metabolomics could be a powerful tool for characterizing aqueous eye fluids and revealing the metabolic signatures of common ocular diseases such as DR, studies about its relationship with DR are limited. Moreover, to our knowledge, no previous study has applied a metabolomic approach to investigate the aqueous humor in DR. Therefore, we performed an NMR-based metabolomic study of the aqueous humor of patients with DM and cataract (DM, n = 13), DR and cataract (DR, n = 14), and senile cataract (CON, n = 7) to investigate the metabolic alterations accompanying the development of DR. Principal component analysis, average change analysis, and heatmap analysis revealed that lactate, succinate, 2-hydroxybutyrate, asparagine, dimethylamine, histidine, threonine, and glutamine were the most altered metabolites that potentially play roles in the development and progression of DR. The highly activated alanine, aspartate, and glutamate metabolic pathway was selected using pathway analysis. The phenotypic metabolomic analyses of the aqueous humor indicated an alteration in the metabolic pathways of energy metabolism and amino acids in DR patients which was to some extent suggestive of the pathophysiological process of mitochondrial dysfunction and oxidative stress/endothelial damage. It provides a proof of concept that metabolomic analysis using the aqueous humor of DM patients may be a reliable method to improve the accuracy of predicting the development and progression of DR.

Elevated plasma and vitreous levels of leucine-rich-α2-glycoprotein are associated with diabetic retinopathy progression.

PURPOSE: To investigate the association of plasma and vitreous leucine-rich-α2-glycoprotein (LRG1) with diabetic retinopathy (DR) progression. METHODS: A total of 86 outpatients and 33 inpatients were recruited. Outpatients with type 2 diabetes mellitus (T2DM) were classified as T2DM without DR (n = 22), nonproliferative DR (NPDR) (n = 20) and proliferative DR (PDR) (n = 22) based on international clinical DR severity scales. A total of 86 plasma and 33 vitreous samples were collected and subjected to enzyme-linked immunosorbent assay. The diagnostic value of plasma LRG1 was tested using receiver operating characteristic (ROC) curves. RESULTS: Plasma LRG1 in PDR patients (9025 ± 1870 pg/ml) was significantly increased as compared with controls (5975 ± 2022 pg/ml), T2DM without DR (6550 ± 2359 pg/ml) and NPDR patients (6550 ± 2359 pg/ml) (p < 0.0001). Vitreous LRG1 in PDR patients was elevated by approximately 4.3-fold than that in controls (562.1 ± 273.5 ng/ml versus 130.0 ± 102.8 ng/ml, p = 0.000). The area under the ROC curve value for plasma LRG1 was 0.786 (p < 0.0001). The maximal Youden index was 0.4372 and the optimal cut-off value of LRG1 was 7357.043 pg/ml with 81.82% sensitivity and 61.90% specificity. CONCLUSION: Plasma and vitreous LRG1 levels were elevated in patients with PDR. Leucine-rich-α2-glycoprotein (LRG1) might be a potential risk-warning marker for PDR.

Changes in Retinal Nerve Fiber Layer Thickness after Multiple Injections of Novel VEGF Decoy Receptor Conbercept for Various Retinal Diseases.

Conbercept is a recombinant fusion protein with high affinity for all vascular endothelial growth factor isoforms and placental growth factor. The repeated intravitreal injection of conbercept may cause intraocular pressure (IOP) fluctuations and long-term suppression of neurotrophic cytokines, which could lead to retinal nerve fiber layer (RNFL) damage. This retrospective fellow-eye controlled study included 98 eyes of 49 patients. The changes in IOP and RNFL thickness as well as the correlation between RNFL changes and associated factors were evaluated. The IOP value between the baseline and the last follow-up visit in the injection group and the IOP value of the last follow-up visit between the injection and non-injection groups were not significantly different (p = 0.452 and 0.476, respectively). The global average thickness of the RNFL (µm) in the injection group decreased from 108.9 to 106.1; however, the change was not statistically significant (p = 0.118). No significant difference in the average RNFL thickness was observed at the last follow-up visit between the injection and non-injection groups (p = 0.821). The type of disease was the only factor associated with RNFL thickness changes. In conclusion, repeated intravitreal injections with 0.05 mL conbercept revealed an excellent safety profile for RNFL thickness, although short-term IOP changes were observed.

DNA sequencing of a plasmid with virulence from marine fish pathogen Vibrio anguillarum.

DNA sequence of a plasmid pEIB1 associated with virulence from the marine fish pathogen Vibrio anguillarum was determined using the methods of restriction endonuclease digestion, subcloning, and primer walking. The whole length of obtained pEIB1 DNA sequence was 66 164 bp, and the overall G+C content of DNA sequence is 42.7%. This sequence encodes 44 open reading frames containing the genes of DNA replication, biosynthesis and regulation of the siderophore anguibactin and transport of ferric-anguibactin complexes.

MicroRNA-93 inhibits inflammatory cytokine production in LPS-stimulated murine macrophages by targeting IRAK4.

Endotoxin-induced uveitis (EIU) is an animal model of acute ocular inflammation for the study of human endogenous anterior uveitis. The mechanisms accounting for the development of ocular inflammation remain hazy. MicroRNAs (mi-RNAs) have been proposed as novel regulators of inflammation. It remains unclear whether a microRNA-mediated regulatory mechanism is involved in LPS-induced EIU. In this study, we report that miR-93 expression in the eyes of EIU rats and LPS-stimulated macrophages is significantly decreased. We also show that miR-93 inhibits NF-κB activation and pro-inflammatory cytokines by targeting IRAK4 expression. We further demonstrate that miR-93 inhibits IRAK4 expression by binding directly to the 3'-UTR of IRAK4. Our findings suggest that miR-93 is a negative regulator of the immune response in EIU.

Treatment effects of captopril on non-proliferative diabetic retinopathy.

BACKGROUND: Diabetic retinopathy (DR) is one of the most common complications of diabetes. Angiotensin-converting enzyme inhibitor is thought to play an important role in preventing and treating retinal diseases in animal models of DR. The aim of the present study was to investigate the role of angiotensin-converting enzyme inhibitor (ACEI, captopril) in the treatment of patients with non-proliferative DR. METHODS: Three hundred and seventeen type 2 diabetic patients (88.05% of participants) without or with mild to moderate non-proliferative retinopathy were randomly divided into captopril group (n = 202) and placebo group (n = 115). All subjects received 24-month follow-up. General clinical examinations, including blood pressure and glycated hemoglobin, as well as comprehensive standardized ophthalmic examinations were performed. Color fundus photography and optical coherence tomography (OCT) were used to grade diabetic retinopathy and detect macular edema respectively. RESULTS: The levels of blood pressure and glycated hemoglobin in the two groups of patients remained within the normal range during the entire follow-up and no significant difference was found between the initial and last visits, suggesting that ACEI drugs play a protective role on the DR patients independent of its anti-blood pressure role. DR classification showed that 169 eyes (83.66%) remained unchanged and the DR grade of 33 eyes (16.34%) increased in captopril group, while 84 eyes (73.04%) remained unchanged and the grade of 31 eyes (26.96%) increased in placebo group (P = 0.024). Captopril treatment improved macular edema in 55.45% eyes, which was significantly higher than the 37.39% improvement in placebo group (P = 0.002). No significant difference was found in the visual acuity between the two groups (P = 0.271). CONCLUSION: Captopril can improve or delay the development of DR and macular edema, which can be used in the early treatment of DR patients with type 2 diabetic mellitus.

Sirtuin 1-mediated cellular metabolic memory of high glucose via the LKB1/AMPK/ROS pathway and therapeutic effects of metformin.

Cellular metabolic memory occurs in diabetic microvascular and macrovascular complications, but the underlying mechanisms remain unclear. Here, we investigate the role of sirtuin 1 (SIRT1) and metformin in this phenomenon. In bovine retinal capillary endothelial cells (BRECs) and retinas of diabetic rats, the inflammatory gene, nuclear factor-κB (NF-κB), and the proapoptotic gene, Bax, induced by hyperglycemia, remained elevated after returning to normoglycemia. BRECs with small interfering RNA-mediated SIRT1 knockdown had increased sensitivity to hyperglycemia stress, whereas SIRT1 overexpression or activation by metformin inhibited the increase of mitochondrial reactive oxygen species-mediated glyceraldehyde-3-phosphate dehydrogenase by poly (ADP-ribose) polymerase (PARP) activity through the upregulation of liver kinase B1/AMP-activated protein kinase (LKB1/AMPK), ultimately suppressing NF-κB and Bax expression. Furthermore, we showed that hyperglycemia led to PARP activation, which in turn may have downregulated SIRT1. Of importance, this study also demonstrated that metformin suppressed the "memory" of hyperglycemia stress in the diabetic retinas, which may be involved in the SIRT1/LKB1/AMPK pathway. Our data suggest that SIRT1 is a potential therapeutic target for the treatment of the cellular metabolic memory, and the use of metformin specifically for such therapy may be a new avenue of investigation in the diabetes field.

Effects of a novel peptide derived from human thrombomodulin on endotoxin-induced uveitis in vitro and in vivo.

Thrombomodulin (TM) is a single-transmembrane glycoprotein receptor for thrombin, which is best known as a cofactor for thrombin-mediated activation of anticoagulant protein C. C-type lectin-like domain (CTLD) of TM has distinct coagulation/fibrinolysis-independent anti-inflammatory properties. Here we found anti-inflammatory effects of a novel peptide (GC31) from CTLD of TM in endotoxin-induced uveitis, which was characterized by a reduction of leukocyte counts, protein concentration, tumor necrosis factor (TNF)-α and monocyte chemoattractant protein (MCP)-1 levels in aqueous humor. Through in vitro experiments, we further found that GC31 suppressed TNF-α and interleukin (IL)-6 expressions in lipopolysaccharide (LPS)-stimulated macrophage-like RAW264.7 cells and interrupted LPS-induced nuclear factor-κB (NF-κB) activation. These data indicate a beneficial role of peptide GC31 in preventing intraocular inflammatory response, especially uveitis.