Characteristics of macular microvasculature before and after idiopathic macular hole surgery.

AIM: To evaluate the macular microvasculature before and after surgery for idiopathic macular hole (MH) and the association of preoperative vascular parameters with postoperative recovery of visual acuity and configuration. METHODS: Twenty eyes from 20 patients with idiopathic MH were enrolled. Optical coherence tomography angiography (OCTA) images were obtained before, 2wk, 1, and 3mo after vitrectomy with internal limiting membrane peeling. Preoperative foveal avascular zone (FAZ) area and perimeter and regional vessel density (VD) in both layers were compared according to the 3-month best-corrected visual acuity (BCVA). RESULTS: The BCVA improved from 0.98±0.59 (logMAR, Snellen 20/200) preoperatively to 0.30±0.25 (Snellen 20/40) at 3mo postoperatively. The preoperative deep VD was smaller and the FAZ perimeter was larger in the 3-month BCVA<20/32 group (all P<0.05). A significant reduction was observed in FAZ parameters and all VDs 2wk postoperatively. Except for deep perifoveal VD, all VDs recovered only to their preoperative values. The postoperative FAZ parameters were lower during follow-up. Decreases in preoperative deep VDs were correlated with worse postoperative BCVA (Pearson's r=-0.667 and -0.619, respectively). A larger FAZ perimeter (Spearman's r=-0.524) and a lower deep perifoveal VD preoperatively (Pearson's r=0.486) were associated with lower healing stage. CONCLUSION: The status of the deep vasculature may be an indicator of visual acuity in patients with a closed MH. Except for the deep perifoveal region, VD recovers only to preoperative levels.

Increased miR-155 in Microglial Exosomes Following Heat Stress Accelerates Neuronal Autophagy via Their Transfer Into Neurons.

Background: Heat stroke is the outcome of excessive heat stress, which results in core temperatures exceeding 40°C accompanied by a series of complications. The brain is particularly vulnerable to damage from heat stress. In our previous studies, both activated microglia and increased neuronal autophagy were found in the cortices of mice with heat stroke. However, whether activated microglia can accelerate neuronal autophagy under heat stress conditions is still unknown. In this study, we aimed to investigate the underlying mechanism that caused neuronal autophagy upregulation in heat stroke from the perspective of exosome-mediated intercellular communication. Methods: In this study, BV2 and N2a cells were used instead of microglia and neurons, respectively. Exosomes were extracted from BV2 culture supernatants by ultracentrifugation and then characterized via transmission electron microscopy, nanoparticle tracking analysis and Western blotting. N2a cells pretreated with/without miR-155 inhibitor were cocultured with microglial exosomes that were treated with/without heat stress or miR-155 overexpression and subsequently subjected to heat stress treatment. Autophagy in N2a cells was assessed by detecting autophagosomes and autophagy-related proteins through transmission electron microscopy, immunofluorescence, and Western blotting. The expression of miR-155 in BV2 and BV2 exosomes and N2a cells was measured using real-time reverse transcription polymerase chain reaction. Target binding analysis was verified via a dual-luciferase reporter assay. Results: N2a autophagy moderately increased in response to heat stress and accelerated by BV2 cells through transferring exosomes to neurons. Furthermore, we found that neuronal autophagy was positively correlated with the content of miR-155 in microglial exosomes. Inhibition of miR-155 partly abolished autophagy in N2a cells, which was increased by coculture with miR-155-upregulated exosomes. Mechanistic analysis confirmed that Rheb is a functional target of miR-155 and that microglial exosomal miR-155 accelerated heat stress-induced neuronal autophagy mainly by regulating the Rheb-mTOR signaling pathway. Conclusion: Increased miR-155 in microglial exosomes after heat stroke can induce neuronal autophagy via their transfer into neurons. miR-155 exerted these effects by targeting Rheb, thus inhibiting the activity of mTOR signaling. Therefore, miR-155 could be a promising target for interventions of neuronal autophagy after heat stroke.

The involvement of microglial CX3CR1 in heat acclimation-induced amelioration of adult hippocampal neurogenesis impairment in EMF-exposed mice.

Microglial CX3C chemokine receptor 1 (CX3CR1) has been implicated in numerous cellular mechanisms, including signalling pathways that regulate brain homoeostasis and adult hippocampal neurogenesis. Specific environmental conditions can impair hippocampal neurogenesis-related cognition, learning and memory. However, the role of CX3CR1 in the neurogenic alterations resulting from the cross-tolerance protection conferred by heat acclimation (HA) against the effects of electromagnetic field (EMF) exposure is less well understood. Here, we investigated the role of microglial CX3CR1 signalling in adult hippocampal neurogenesis induced by HA in EMF-exposed mice. We found that EMF exposure significantly decreased the number of proliferating and differentiating cells in the dentate gyrus (DG) of the hippocampus, resulting in a reduced neurogenesis rate. Moreover, alterations in the phenotypes of activated microglia and decreased expression levels of CX3CR1, but not sirtuin 1 (SIRT1), were observed in the brains of EMF-exposed mice. Remarkably, HA treatment improved microglial phenotypes, restored the expression of CX3CR1, and ameliorated the decrease in the adult hippocampal neurogenesis rate following EMF exposure. Moreover, pharmacological inhibition of CX3CR1 and SIRT1 failed to restore CX3CR1 expression and ameliorate hippocampal neurogenesis impairment following HA plus EMF stimulation. These results indicate that microglial CX3CR1 is involved in the cross-tolerance protective effect of HA on adult hippocampal neurogenesis upon EMF exposure.

The Undervalued Effects of Polychlorinated Biphenyl Exposure on Breast Cancer.

The incidence of breast cancer across the world has been on the rise in recent decades. Because identified risk factors can only explain a relatively small portion of the cases, environmental exposure to organic pollutants is suspected to play a role in breast cancer etiology. Polychlorinated biphenyls (PCBs) are among the most abundant pollutants, and the impact of their exposure on breast cancer risk has been extensively studied in recent decades. However, the results of most epidemiologic studies do not support an association between PCB exposure and breast cancer risk. We hypothesized that the effects of PCBs on breast cancer might have been undervalued for reasons such as insufficient recognition of the confounding effects of several factors and lack of attention on the innate heterogeneity of PCB mixtures or breast cancer. After reviewing the evidence in the existing literature, we concluded that early life exposure, known risk factors of breast cancer, and impact of exposure to other pollutants are the main sources of confounding effects and have potentially masked the associations between PCBs and breast cancer. Because PCBs are mixtures of congeners with varied properties, and because breast cancers of different subtypes are etiologically distinct diseases, the absence of stratified subgroup analysis on individual PCBs and patients with specific biological subtypes and insufficient attention paid to the results of these subgroup analyses may result in an underestimation of the correlations between PCBs and breast cancer. In future studies, these factors must be taken into consideration when exploring the effect of PCB exposure on breast cancer risk.

Quinones as preventive agents in Alzheimer's diseases: focus on NLRP3 inflammasomes.

OBJECTIVES: Alzheimer's disease (AD) is a hidden neurological degenerative disease, which main clinical manifestations are cognitive dysfunction, memory impairment and mental disorders. Neuroinflammation is considered as a basic response of the central nervous system. NLRP3 (Nucleotide-binding domain leucine-rich repeat (NLR) and pyrin domain containing receptor 3) inflammasome is closely related to the occurrence of neuroinflammation. Activation of the NLRP3 inflammasome results in the release of cytokines, pore formation and ultimately pyroptosis, which has demonstrated one of the critical roles in AD pathogenesis. Inhibition of the activity of NLRP3 is one of the focuses of the research. Therefore, NLRP3 represents an attractive pharmacological target, and discovery compounds with good NLRP3 inhibitory activity are particularly important. KEY FINDINGS: Quinones have good neuroprotective effects and prevent AD, which may be related to their regulation of inflammatory response. The molecular docking was used to explore 12 quinones with AD prevention and treatment and NLRP3. Docking results showed that the combination of anthraquinones and NLRP3 were the best, and the top two chemical compounds were Purpurin and Rhein, which are the most promising NLRP3 inhibitors. SUMMARY: These quinones may provide the theoretical basis for finding lead compounds for novel neuroprotective agents.

Neoadjuvant endocrine therapy: A potential strategy for ER-positive breast cancer.

A potential strategy for patients with estrogen receptor (ER)-positive breast cancer is necessary to replace neoadjuvant chemotherapy which has limited benefit. Neoadjuvant endocrine therapy (NAE) has been indicated to be a favorable alternate approach to downstage large or locally advanced breast cancer in ER-positive, human epidermal growth factor receptor 2 (HER2)-negative (ER+/HER2-) patients, especially postmenopausal women. Previous studies have demonstrated the efficacy of various endocrine agents in NAE. Aromatase inhibitors (AIs) have proven superiority over tamoxifen as a suitable choice to optimize treatment efficacy. Fulvestrant was recently reported as an effective agent, similar to AIs. Furthermore, the addition of targeted agents exerts synergistic antiproliferative effects with endocrine agents and rapidly improves response rates in both endocrine sensitive and resistant tumors. The neoadjuvant platform provides a unique opportunity to define the appropriate strategy and address the mechanisms of endocrine resistance. In addition, the predictive value of biomarkers and genomic assays in NAE is under investigation to evaluate individual effects and validate biomarker-based strategies. In this review, we discuss the most relevant evidence on the potential of NAE for ER+ breast cancer. The current understanding also offers new insights into the identification of the optimal settings and valuable predictive tools of NAE to guide clinical treatment decisions and achieve beneficial therapeutic effects.

Comparison of persistent submacular fluid in different preoperative macular status after vitrectomy for rhegmatogenous retinal detachment.

AIM: To compare the incidence of persistent submacular fluid (SMF) and visual outcome after pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RRD) in different preoperative macular status according to optical coherence tomography (OCT). METHODS: A non-randomized, retrospective review was performed for patients who underwent successful PPV for RRD. OCT exams were taken preoperatively and 1mo after surgery, until SMF disappeared. According to the preoperative macular status on OCT, patients were divided into two groups: macula-off RRD (Group A) and macula-on RRD (Group B). In Group A, there were two subgroups: macula partly detached (Group A1) and macula totally detached (Group A2). The main outcome measures were the presence of SMF on OCT 1mo after surgery, and the preoperative and postoperative best corrected visual acuities (BCVA), among the different groups and depending on the presence or absence of persistent SMF. RESULTS: A total of 139 eyes of 139 patients were included in the study. Persistent SMF at 1mo after surgery was 15.8% (22/139), all occurring in Group A (22/101); Group B had no SMF at 1mo after surgery (0/38, P=0.002). The incidence of persistent SMF at 1mo after surgery in Group A1 was 50% (14/28), and in Group A2 was 11.0% (8/73, P<0.001). Significant differences were shown between the presence and absence of persistent SMF on foveola-off RRD, the preoperative BCVA, the 1mo postoperative BCVA, and the degree of the BCVA improvement from 1mo postoperatively to the final follow-up (P<0.05). However, there were no significant differences in the final BCVA (P>0.05). CONCLUSION: Persistent SMF after PPV for retinal detachment is associated with preoperative macular status. Macula-uninvolving RRD shows no persistent SMF after PPV. Macular partly detached RRD has a higher incidence of SMF than macula totally detached RRD after PPV. The persistence of SMF may be responsible for the delayed visual recovery, whereas there were no significant differences in the final visual acuity.