Mendelian randomization study and mediation analysis about the relation of inflammatory bowel disease and diabetic retinopathy: the further exploration of gut-retina axis.

Background: The concept of the gut-retinal axis proposed by previous scholars primarily focused on the relationship between intestinal microbiota and retinal diseases, and few further expanded the relationship between intestinal diseases and retinal diseases. To further substantiate the concept of the gut-retinal axis, we analyzed inflammatory bowel disease (IBD) and diabetic retinopathy (DR) using Mendelian randomization (MR), and use mediation analysis to further explore the potential substances that influence this causal relationship. Methods: The genome-wide association study's (GWAS) summary statistics for genetic variations were utilized in a Mendelian randomization (MR) investigation. GWAS data on IBD (including ulcerative colitis (UC), Crohn's disease (CD), and IBD) for non-Finnish Europeans (NFE) were sourced from published articles. In contrast, data on DR (including DR and diabetic maculopathy (DMP)) were obtained from FinnGen R9. The causal relationship has been investigated using inverse variance weighted (IVW), MR-Egger, and weighted median and sensitivity analysis was applied to verify the stability of the results. In addition, we applied mediation analysis to investigate whether circulating inflammatory proteins and plasma lipids played a mediating role, and calculated its effect ratio. Results: The causal relationship between IBD and DR was discovered by employing the inverse variance weighted (IVW) method and weighted median method. In forward MR, UC was significantly associated with lower risk of DR (IVW: OR=0.874; 95%CI= 0.835-0.916; P value= 1.28E-08) (Weighted median: OR=0.893; 95%CI= 0.837-0.954; P value= 7.40E-04). In reverse MR, it was shown that DR (IVW: OR=0.870; 95%CI= 0.828-0.914; P value= 2.79E-08)(Weighted median: OR=0.857; 95%CI= 0.801-0.916; P value= 6.40E-06) and DMP (IVW: OR=0.900; 95%CI= 0.865-0.937; P value= 3.34E-07)(Weighted median: OR=0.882; 95%CI= 0.841-0.924; P value= 1.82E-07) could reduce the risk of CD. What's more, DR is associated with a lower risk of IBD according to genetic prediction (IVW: OR=0.922; 95%CI= 0.873-0.972; P value= 0.002) (Weighted median: OR=0.924; 95%CI= 0.861-0.992; P value= 0.029). Fibroblast growth factor 21 (FGF21), phosphatidylcholine (PC), and triacylglycerol (TG) serve as mediators in these relationships. Conclusions: Our research offers novel insights and sources for investigating the gut-retina axis in the genetic relationship between IBD and DR. We discover four mediators and more about the association between the intestine and retinal disorders and provide more evidence for the gut-retinal axis theory.

Effects of chemokine receptor CCR7 in the pathophysiology and clinical features of the immuno-inflammatory response in primary pterygium.

OBJECTIVE: Chemokine receptor 7 (CCR7) has been considered a critical biomarker in inflammation and the immune response; however, little is known about CCR7 in pterygia. This study aimed to investigate whether CCR7 participates in the pathogenesis of primary pterygia and how CCR7 affects the progression of pterygia. METHODS: This was an experimental study. Slip-lamp photographs of 85 pterygium patients were used to measure the width, extent, and area of pterygia with computer software. Pterygium blood vessels and general ocular redness were quantitatively analyzed with a specific algorithm. The expression of CCR7 and its ligands C-C motif ligand 19 (CCL19) and C-C motif ligand 21 (CCL21) in control conjunctivae and excised pterygia collected during surgery were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and immunofluorescence staining. The phenotype of CCR7-expressing cells was identified by costaining for major histocompatibility complex II (MHC II), CD11b or CD11c. RESULTS: The CCR7 level was significantly increased by 9.6-fold in pterygia compared with control conjunctivae (p = 0.008). The higher the expression of CCR7 was, the more blood vessels appeared in pterygia (r = 0.437, p = 0.002) and the more general ocular redness was (r = 0.51, p < 0.001) in pterygium patients. CCR7 was significantly associated with pterygium extent (r = 0.286, p = 0.048). In addition, we found that CCR7 colocalized with CD11b, CD11c or MHC II in dendritic cells, and immunofluorescence staining showed that CCR7-CCL21 is a potential chemokine axis in pterygium. CONCLUSIONS: This work verified that CCR7 impacts the extent of primary pterygia invading the cornea and inflammation at the ocular surface, which may provide a possibility for a further in-depth understanding of the immunological mechanism in pterygia.

Melatonin enhances hydrogen peroxide-induced apoptosis in human dental pulp cells.

BACKGROUND/PURPOSE: Melatonin, at physiological concentrations, was previously found to inhibit proliferation and promote odontogenic differentiation in human dental pulp cells (hDPCs), but its effect on apoptosis is unclear. Our study aimed to investigate the effect of melatonin on the H2O2-mediated viability reduction and apoptosis in hDPCs. MATERIALS AND METHODS: hDPCs were treated with H2O2 (0, 250, 500, 1000 µmol/L), melatonin (0, 10-12, 10-10, 10-8 mol/L), and melatonin with H2O2 for 24 h. CCK-8 assays were performed to evaluate cell viability. Apoptosis was measured by DAPI and Annexin V/propidium iodide staining. Intracellular reactive oxygen species (ROS) were measured by CellROX® staining and mitochondrial membrane potential (ΔΨm) was examined by JC-1 staining. RESULTS: H2O2 obviously decreased the viability of hDPCs in a concentration-dependent manner and melatonin alone also reduced viability by 16-20%. Melatonin was also found to enhance H2O2-induced toxicity in a concentration-dependent manner, and the highest physiological concentration of melatonin (10-8 mol/L) had the most obvious effect (P < 0.001). Treating H2O2-exposed hDPCs with melatonin significantly increased the ratio of apoptotic cells with condensed and deformed nuclei (P < 0.001), as well as the percentage of Annexin V-positive cells (P < 0.01). Furthermore, melatonin significantly increased intracellular ROS levels and induced the loss of ΔΨm in H2O2-exposed cells (P < 0.05). CONCLUSION: Our results indicate that melatonin, at physiological concentrations, can enhance H2O2-induced apoptosis in hDPCs and increase H2O2-mediated ROS production and ΔΨm loss. Further studies are needed to investigate whether melatonin targets the mitochondrial death pathway during the process.

Electrochemical detection of beta-1,3-glucanase gene from transgenic capsicums using asymmetric PCR generated by a detecting probe and an anchoring probe.

A design for recognition of beta-1,3-glucanase gene (Glu) specific sequence based on probe extension was described. The detecting probe DNA and the anchoring prober were hybridized with the same target DNA firstly, then the probes were extended by DNA polymerase reaction. After that the double strand DNA was denatured, and the extended detecting probe was immobilized on a glassy carbon electrode via nanoparticle gold (AuNP). In electrochemical detection (cyclic voltammetry, CV and differential pulse voltammetry, DPV), an increased peak current (i(p)) of the indicator (methylene blue, MB) was obtained compared with the probe without extension. Three differently long DNAs of Glu specific sequence were employed as the target: oligonucleotide acid, molecular cloning vector DNA and total genome DNA of transgenic capsicum. The estimated DPV detection limits for three targets of oligonucleotide, the molecular cloning vector DNA and genome DNA were 2.6x10(-13), 6.0x10(-13) and 8.0x10(-13)moll(-1) respectively.

An electrochemical assay of beta-1,3-glucanase gene from transgenic capsicum using asymmetric PCR.

5'-Thiol-derivatized specific DNA probes were added to the single primer polymerase chain reaction (asymmetric PCR) solution. In the PCR process, the DNA probes extended in the presence of target; the extended probes were then immobilized on a glassy carbon electrode (GCE) via gold nanoparticles. Finally, methylene blue and the extended probes were combined and the electrochemical signals were measured. This signal was higher than that of the GCE modified only by the original probe. When there was no target in PCR solution, the probe did not extend and the signal did not increase. The specific sequences of the beta-1,3-glucanase gene were detected successfully from three targets with different length: oligonucleotide, molecule clone vector DNA, and total genome DNA of transgenic capsicum. The detection limits of 2.6 x 10(-13), 7.8 x 10(-13), and 9.1 x 10(-13) moll(-1) for oligonucleotide, molecule clone vector DNA, and total transgenic capsicum genome DNA were estimated.