Repopulating Microglia Promote Brain Repair in an IL-6-Dependent Manner.

Cognitive dysfunction and reactive microglia are hallmarks of traumatic brain injury (TBI), yet whether these cells contribute to cognitive deficits and secondary inflammatory pathology remains poorly understood. Here, we show that removal of microglia from the mouse brain has little effect on the outcome of TBI, but inducing the turnover of these cells through either pharmacologic or genetic approaches can yield a neuroprotective microglial phenotype that profoundly aids recovery. The beneficial effects of these repopulating microglia are critically dependent on interleukin-6 (IL-6) trans-signaling via the soluble IL-6 receptor (IL-6R) and robustly support adult neurogenesis, specifically by augmenting the survival of newborn neurons that directly support cognitive function. We conclude that microglia in the mammalian brain can be manipulated to adopt a neuroprotective and pro-regenerative phenotype that can aid repair and alleviate the cognitive deficits arising from brain injury.

Challenges and perspectives in computational deconvolution of genomics data.

Deciphering cell-type heterogeneity is crucial for systematically understanding tissue homeostasis and its dysregulation in diseases. Computational deconvolution is an efficient approach for estimating cell-type abundances from a variety of omics data. Despite substantial methodological progress in computational deconvolution in recent years, challenges are still outstanding. Here we enlist four important challenges related to computational deconvolution: the quality of the reference data, generation of ground truth data, limitations of computational methodologies, and benchmarking design and implementation. Finally, we make recommendations on reference data generation, new directions of computational methodologies, and strategies to promote rigorous benchmarking.

Functional genomics analysis identifies loss of HNF1B function as a cause of Mayer-Rokitansky-Küster-Hauser syndrome.

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a congenital condition characterized by aplasia or hypoplasia of the uterus and vagina in women with a 46,XX karyotype. This condition can occur as type I when isolated or as type II when associated with extragenital anomalies including kidney and skeletal abnormalities. The genetic basis of MRKH syndrome remains unexplained and several candidate genes have been proposed to play a role in its etiology, including HNF1B, LHX1 and WNT4. Here, we conducted a microarray analysis of 13 women affected by MRKH syndrome, resulting in the identification of chromosomal changes, including the deletion at 17q12, which contains both HNF1B and LHX1. We focused on HNF1B for further investigation due to its known association with, but unknown etiological role in, MRKH syndrome. We ablated Hnf1b specifically in the epithelium of the Müllerian ducts in mice and found that this caused hypoplastic development of the uterus, as well as kidney anomalies, closely mirroring the MRKH type II phenotype. Using single-cell RNA sequencing of uterine tissue in the Hnf1b-ablated embryos, we analyzed the molecules and pathways downstream of Hnf1b, revealing a dysregulation of processes associated with cell proliferation, migration and differentiation. Thus, we establish that loss of Hnf1b function leads to an MRKH phenotype and generate the first mouse model of MRKH syndrome type II. Our results support the investigation of HNF1B in clinical genetic settings of MRKH syndrome and shed new light on the molecular mechanisms underlying this poorly understood condition in women's reproductive health.

Inferring cell diversity in single cell data using consortium-scale epigenetic data as a biological anchor for cell identity.

Methods for cell clustering and gene expression from single-cell RNA sequencing (scRNA-seq) data are essential for biological interpretation of cell processes. Here, we present TRIAGE-Cluster which uses genome-wide epigenetic data from diverse bio-samples to identify genes demarcating cell diversity in scRNA-seq data. By integrating patterns of repressive chromatin deposited across diverse cell types with weighted density estimation, TRIAGE-Cluster determines cell type clusters in a 2D UMAP space. We then present TRIAGE-ParseR, a machine learning method which evaluates gene expression rank lists to define gene groups governing the identity and function of cell types. We demonstrate the utility of this two-step approach using atlases of in vivo and in vitro cell diversification and organogenesis. We also provide a web accessible dashboard for analysis and download of data and software. Collectively, genome-wide epigenetic repression provides a versatile strategy to define cell diversity and study gene regulation of scRNA-seq data.

Single-cell RNA sequencing reveals peripheral blood leukocyte responses to spinal cord injury in mice with humanised immune systems.

Next-generation humanised mouse models and single-cell RNA sequencing (scRNAseq) approaches enable in-depth studies into human immune cell biology. Here we used NSG-SGM3 mice engrafted with human umbilical cord haematopoietic stem cells to investigate how human immune cells respond to and/or are changed by traumatic spinal cord injury (SCI). We hypothesised that the use of such mice could help advance our understanding of spinal cord injury-induced immune depression syndrome (SCI-IDS), and also how human leukocytes change as they migrate from the circulation into the lesion site. Our scRNAseq experiments, supplemented by flow cytometry, demonstrate the existence of up to 11 human immune cell (sub-) types and/or states across the blood and injured spinal cord (7 days post-SCI) of humanised NSG-SGM3 mice. Further comparisons of human immune cell transcriptomes between naïve, sham-operated and SCI mice identified a total of 579 differentially expressed genes, 190 of which were 'SCI-specific' (that is, genes regulated only in response to SCI but not sham surgery). Gene ontology analysis showed a prominent downregulation of immune cell function under SCI conditions, including for T cell receptor signalling and antigen presentation, confirming the presence of SCI-IDS and the transcriptional signature of human leukocytes in association with this phenomenon. We also highlight the activating influence of the local spinal cord lesion microenvironment by comparing the transcriptomes of circulating versus infiltrated human immune cells; those isolated from the lesion site were enriched for genes relating to both immune cell activity and function (e.g., oxidative phosphorylation, T cell proliferation and antigen presentation). We lastly applied an integrated bioinformatics approach to determine where immune responses in humanised NSG-SGM3 mice appear congruent to the native responses of human SCI patients, and where they diverge. Collectively, our study provides a valuable resource and methodological framework for the use of these mice in translational research.

Spatial omics and multiplexed imaging to explore cancer biology.

Understanding intratumoral heterogeneity-the molecular variation among cells within a tumor-promises to address outstanding questions in cancer biology and improve the diagnosis and treatment of specific cancer subtypes. Single-cell analyses, especially RNA sequencing and other genomics modalities, have been transformative in revealing novel biomarkers and molecular regulators associated with tumor growth, metastasis and drug resistance. However, these approaches fail to provide a complete picture of tumor biology, as information on cellular location within the tumor microenvironment is lost. New technologies leveraging multiplexed fluorescence, DNA, RNA and isotope labeling enable the detection of tens to thousands of cancer subclones or molecular biomarkers within their native spatial context. The expeditious growth in these techniques, along with methods for multiomics data integration, promises to yield a more comprehensive understanding of cell-to-cell variation within and between individual tumors. Here we provide the current state and future perspectives on the spatial technologies expected to drive the next generation of research and diagnostic and therapeutic strategies for cancer.

LmTag: functional-enrichment and imputation-aware tag SNP selection for population-specific genotyping arrays.

Despite the rapid development of sequencing technology, single-nucleotide polymorphism (SNP) arrays are still the most cost-effective genotyping solutions for large-scale genomic research and applications. Recent years have witnessed the rapid development of numerous genotyping platforms of different sizes and designs, but population-specific platforms are still lacking, especially for those in developing countries. SNP arrays designed for these countries should be cost-effective (small size), yet incorporate key information needed to associate genotypes with traits. A key design principle for most current platforms is to improve genome-wide imputation so that more SNPs not included in the array (imputed SNPs) can be predicted. However, current tag SNP selection methods mostly focus on imputation accuracy and coverage, but not the functional content of the array. It is those functional SNPs that are most likely associated with traits. Here, we propose LmTag, a novel method for tag SNP selection that not only improves imputation performance but also prioritizes highly functional SNP markers. We apply LmTag on a wide range of populations using both public and in-house whole-genome sequencing databases. Our results show that LmTag improved both functional marker prioritization and genome-wide imputation accuracy compared to existing methods. This novel approach could contribute to the next generation genotyping arrays that provide excellent imputation capability as well as facilitate array-based functional genetic studies. Such arrays are particularly suitable for under-represented populations in developing countries or non-model species, where little genomics data are available while investment in genome sequencing or high-density SNP arrays is limited. $\textrm{LmTag}$ is available at: https://github.com/datngu/LmTag.

Assessing polygenic risk score models for applications in populations with under-represented genomics data: an example of Vietnam.

Most polygenic risk score (PRS)models have been based on data from populations of European origins (accounting for the majority of the large genomics datasets, e.g. >78% in the UK Biobank and >85% in the GTEx project). Although several large-scale Asian biobanks were initiated (e.g. Japanese, Korean, Han Chinese biobanks), most other Asian countries have little or near-zero genomics data. To implement PRS models for under-represented populations, we explored transfer learning approaches, assuming that information from existing large datasets can compensate for the small sample size that can be feasibly obtained in developing countries, like Vietnam. Here, we benchmark 13 common PRS methods in meta-population strategy (combining individual genotype data from multiple populations) and multi-population strategy (combining summary statistics from multiple populations). Our results highlight the complementarity of different populations and the choice of methods should depend on the target population. Based on these results, we discussed a set of guidelines to help users select the best method for their datasets. We developed a robust and comprehensive software to allow for benchmarking comparisons between methods and proposed a computational framework for improving PRS performance in a dataset with a small sample size. This work is expected to inform the development of genomics applications in under-represented populations. PRSUP framework is available at: https://github.com/BiomedicalMachineLearning/VGP.

High quality factor, monodisperse micron-sized random lasers based on porous PLGA spheres.

Miniature random lasers with high quality factor are crucial for applications in barcoding, bioimaging, and on-chip technologies. However, achieving monodisperse and size-tunable biocompatible random lasers has been a significant challenge. In this study, we employed poly(lactic-co-glycolic) acid (PLGA), a biocompatible material approved for medical use, as the base material for random lasers. By integrating a dye-doped PLGA solution with a microfluidic system, we successfully fabricated monodisperse and miniature dye-doped PLGA spheres with tunable sizes ranging from 25 to 52 µm. Upon optical pulse excitation, these spheres exhibited strong random lasing emission at 610-640 nm with a threshold of approximately 22 µJ·mm-2. The lasing modes demonstrated a spectral linewidth of 0.2 nm, corresponding to a quality factor of 3100. Fourier transform analysis of the lasing emission revealed fundamental cavity lengths, providing insights into the properties of the random lasers.

Ocular syphilis masquerading as refractory retinal diseases.

PURPOSE: To report two cases of syphilis masquerading as chronic refractory macular diseases. CASE DESCRIPTIONS: Two patients had been diagnosed with neovascular age-related macular degeneration (neovascular AMD) and diabetic macular edema (DME), respectively. The disease worsened despite repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF) and also surgical treatment (in suspected case of DME). Systemic evaluations were positive for syphilis. Intravenous penicillin was started, and the macular diseases improved. The lesions were well controlled afterward. CONCLUSIONS: The current two cases demonstrated that ocular syphilis can masquerade as refractory chronic retinal diseases such as DME and neovascular AMD. Laboratory evaluations for syphilis may be needed, not only for uveitis but also for refractory retinal diseases. Indocyanine green angiography may be helpful to reveal occult syphilis.

Epilepsy self-management mobile health application: A needs assessment in people with epilepsy and caregivers in Viet Nam.

OBJECTIVES: This study aimed to determine (1) the needsof Vietnamese people with epilepsy (PWE) and their caregivers for self-management mobile health applications and (2) the self-management features expected to be included in an application. METHODS: The survey consisted of an anonymous self-administered questionnaire that was distributed to PWE and caregivers from the age of 18 in Vietnam through online platforms and onsite at Nguyen Tri Phuong Hospital and University Medical Center, Ho Chi Minh City, from February 2022 to May 2022. The questionnaire assessed the participants' attitudes toward epilepsy self-management mobile applications, their willingness to use applications, and their expectations of the contents of an application. RESULTS: Responses from 103 participants were submitted. Eighty-one participants (78.6%) reported using a smartphone, but only 50.6% of those claimed to know about self-management applications. Most respondents (70.9%) thought the applications would be useful for disease self-management, and 68.9% were willing to use epilepsy self-management applications. In addition, the most expected features to be included in self-management applications were epilepsy information, seizure first aid, connecting with medical professionals, and a seizure diary. CONCLUSION: Most Vietnamese PWE and caregivers had a willingness to use epilepsy self-management applications.The expected features are related to all aspects of self-management, including information, seizure, medication, and safety management.

Sustainability assessment methods for circular bio-based building materials: A literature review.

Using circular bio-based building materials is considered a promising solution to reduce the environmental impacts of the construction industry. To identify the pros and cons of these materials, it is essential to investigate their sustainability performance. However, the previous sustainability assessment studies are heterogeneous regarding the assessment methods and objectives, highlighting the need for a review to identify and analyse these aspects. Moreover, there is still a lack of studies reviewing the methodological issues and implications of the assessment methods, as well as the current end-of-life scenarios and circularity options for these materials. To address these gaps, this study conducts a systematic and critical review of a sample of 97 articles. The results indicate that Life Cycle Assessment (LCA) is the most frequently applied method, yet most studies are cradle-to-gate analyses of materials. Otherwise, very few studies consider the end-of-life phase, and most of the end-of-life scenarios analysed are unsustainable and have low circularity levels. The analysis also highlights the methodological issues of the assessment methods used, with a particular focus on LCA, such as a lack of consensus on system boundaries, functional units, and databases for facilitating sustainability assessments associated with the use of circular bio-based building materials. Two primary recommendations emerge from the analysis. Firstly, for LCA studies, it is recommended to increase transparency and harmonisation in assessments to improve the comparability of results. Besides, to overcome data availability issues, it is recommended to use data from multiple sources and conduct sensitivity and uncertainty analyses. Secondly, more sustainability assessments (including the three pillars) considering the whole life cycle with more sustainable end-of-life scenarios and circularity options for these materials should be conducted.

Status and barriers to circular bio-based building material adoption in developed economies: The case of Flanders, Belgium.

Circular bio-based building materials (CBBMs) provide a potential solution to reduce the climate impacts of buildings and offer opportunities to transition the construction industry to a circular model. Promoting the use of these materials can also bring economic, environmental, and social benefits from valorising biowaste and by-products from other sectors. Despite their potential, CBBMs have not received sufficient attention globally, and their adoption is hindered by various barriers. However, it is unclear what the CBBMs' use status is, what adoption barriers exist, how these barriers interact, and what should be done to address them. This study addresses these knowledge gaps through a systematic study using mixed methods to investigate the adoption status and barriers to these materials in developed economies by using a specific case analysis in Flanders. The data analysis results show that hemp-based, cork-based, and straw-based materials are the most used, while the market for CBBMs is very limited in the region. Twenty-three potential adoption barriers were identified and selected from the existing literature, then ranked based on their mean scores. The t-test analysis helps to identify 13 critical barriers, which are grouped into five categories, including cost and risk-related barriers, technical and cultural-related barriers, the government's role-related barriers, information and quality-related barriers, and market-related barriers. Among them, cost and risk-related barriers, including "concern about the high initial cost", "risks and uncertainties involved in adopting new materials", and "perception of the extra cost being incurred", are the three most critical barriers to CBBM adoption in Flanders. Kendall's W test shows good consensus among the two expert groups-with and without hands-on experience in utilising CBBMs-in their rankings of the barriers. Meanwhile, the Mann-Whitney U test indicates no statistically significant differences in the ranks of barriers between the two expert groups. The interview results confirm almost all survey results and provide deeper insights into the status and barriers to adopting these materials. Practical and policy implications are discussed based on these findings to inform policy deliberations on promoting CBBMs. This study may also be a good reference for scholars and industry practitioners to better understand issues impacting decision-making towards the adoption of CBBMs in the construction industry.

A robust platform for integrative spatial multi-omics analysis to map immune responses to SARS-CoV-2 infection in lung tissues.

The SARS-CoV-2 (COVID-19) virus has caused a devastating global pandemic of respiratory illness. To understand viral pathogenesis, methods are available for studying dissociated cells in blood, nasal samples, bronchoalveolar lavage fluid and similar, but a robust platform for deep tissue characterization of molecular and cellular responses to virus infection in the lungs is still lacking. We developed an innovative spatial multi-omics platform to investigate COVID-19-infected lung tissues. Five tissue-profiling technologies were combined by a novel computational mapping methodology to comprehensively characterize and compare the transcriptome and targeted proteome of virus infected and uninfected tissues. By integrating spatial transcriptomics data (Visium, GeoMx and RNAScope) and proteomics data (CODEX and PhenoImager HT) at different cellular resolutions across lung tissues, we found strong evidence for macrophage infiltration and defined the broader microenvironment surrounding these cells. By comparing infected and uninfected samples, we found an increase in cytokine signalling and interferon responses at different sites in the lung and showed spatial heterogeneity in the expression level of these pathways. These data demonstrate that integrative spatial multi-omics platforms can be broadly applied to gain a deeper understanding of viral effects on cellular environments at the site of infection and to increase our understanding of the impact of SARS-CoV-2 on the lungs.

Tolerogenic dendritic cells protect against acute kidney injury.

Ischemia reperfusion injury is a common precipitant of acute kidney injury that occurs following disrupted perfusion to the kidney. This includes blood loss and hemodynamic shock, as well as during retrieval for deceased donor kidney transplantation. Acute kidney injury is associated with adverse long-term clinical outcomes and requires effective interventions that can modify the disease process. Immunomodulatory cell therapies such as tolerogenic dendritic cells remain a promising tool, and here we tested the hypothesis that adoptively transferred tolerogenic dendritic cells can limit kidney injury. The phenotypic and genomic signatures of bone marrow-derived syngeneic or allogeneic, Vitamin-D3/IL-10-conditioned tolerogenic dendritic cells were assessed. These cells were characterized by high PD-L1:CD86, elevated IL-10, restricted IL-12p70 secretion and a suppressed transcriptomic inflammatory profile. When infused systemically, these cells successfully abrogated kidney injury without modifying infiltrating inflammatory cell populations. They also provided protection against ischemia reperfusion injury in mice pre-treated with liposomal clodronate, suggesting the process was regulated by live, rather than reprocessed cells. Co-culture experiments and spatial transcriptomic analysis confirmed reduced kidney tubular epithelial cell injury. Thus, our data provide strong evidence that peri-operatively administered tolerogenic dendritic cells have the ability to protect against acute kidney injury and warrants further exploration as a therapeutic option. This technology may provide a clinical advantage for bench-to-bedside translation to affect patient outcomes.

A single-cell transcriptome atlas of the adult human retina.

The retina is a specialized neural tissue that senses light and initiates image processing. Although the functional organization of specific retina cells has been well studied, the molecular profile of many cell types remains unclear in humans. To comprehensively profile the human retina, we performed single-cell RNA sequencing on 20,009 cells from three donors and compiled a reference transcriptome atlas. Using unsupervised clustering analysis, we identified 18 transcriptionally distinct cell populations representing all known neural retinal cells: rod photoreceptors, cone photoreceptors, Müller glia, bipolar cells, amacrine cells, retinal ganglion cells, horizontal cells, astrocytes, and microglia. Our data captured molecular profiles for healthy and putative early degenerating rod photoreceptors, and revealed the loss of MALAT1 expression with longer post-mortem time, which potentially suggested a novel role of MALAT1 in rod photoreceptor degeneration. We have demonstrated the use of this retina transcriptome atlas to benchmark pluripotent stem cell-derived cone photoreceptors and an adult Müller glia cell line. This work provides an important reference with unprecedented insights into the transcriptional landscape of human retinal cells, which is fundamental to understanding retinal biology and disease.

Recent advances in uveitis therapy: focus on selected phase 2 and 3 clinical trials.

INTRODUCTION: Uveitis is a heterogeneous group of ocular conditions characterized by inflammation of the uveal tract. It is a leading cause of blindness in developed countries and exerts significant psychological, social, and economic impact on both patients and the larger society. While there are numerous pharmacotherapy options, posterior segment noninfectious uveitis remains a significant challenge to treat due to its severity, chronicity, and high recurrence rates. AREAS COVERED: The index review highlights the unmet needs of uveitis pharmacotherapy and its research and the shortcomings of existing ocular and systemic therapeutic options for noninfectious uveitis. The more promising novel ocular drug delivery methods and therapeutic targets/drugs are discussed, and evidence from the clinical trials is evaluated. EXPERT OPINION: There has been incredible growth in the number of treatment options available to uveitis patients today, especially with the new generation of biologic drugs. Available evidence suggests that these newer options may be superior to conventional immunosuppressive therapies in terms of efficacy and side effect profiles. Further high-quality research and additional clinical trials will be needed to clarify their roles in the stepladder treatment approach of noninfectious uveitis.

Viral-specific T cells for Cytomegalovirus retinitis following hematopoietic stem cell transplantation: A success story.

Cytomegalovirus retinitis (CMVR) following hematopoietic stem cell transplantation (HCT) for a primary immunodeficiency is a rare but highly morbid condition with potential irreversible consequences despite optimal antiviral pharmacotherapy. Viral-specific T cells (VSTs) pose a promising and safe approach eradicating intractable viral disease. We describe the case of a 21-month-old male with Wiskott-Aldrich syndrome (WAS) and CMVR post HCT with sustained long-term virologic and clinical response after CMV-specific T-cell therapy. This case highlights the need to consider VST as an adjunct upfront strategy in refractory CMVR and for routine ophthalmologic screening and surveillance in high-risk patients post HCT.

Evaluation of correlation between Diopsys® NOVA™ fixed-luminance flicker ERG and Diagnosys® Espion 2™ flicker ERG parameters.

PURPOSE: Diopsys® NOVA™ is a novel full-field electroretinography (ffERG) device that can make rapid measurements of retinal electrophysiologic function. Diagnosys® Espion 2™ is a clinical gold-standard ERG device. This study aimed to investigate whether light-adapted Diopsys® NOVA™ fixed-luminance flicker ffERG magnitude and implicit time (converted from phase) measurements correlate with light-adapted Diagnosys® Espion 2™ flicker ffERG amplitude and implicit time measurements, respectively. METHODS: Twelve patients (22 eyes) with various retinal and uveitic diseases underwent light-adapted Diagnosys® Espion 2™ and Diopsys® NOVA™ fixed-luminance flicker testing. Diopsys® magnitude and implicit time (converted from phase) measurements were compared to Diagnosys® amplitude and implicit time measurements, and a Pearson correlation was used to evaluate any existing correlation. Groups were also compared using generalized estimating equations. Bland-Altman plots were utilized to determine agreement between the comparison groups. RESULTS: Age of patients ranged from 14 to 87 years. 58% (n = 7/12) of patients were female. A significant, positive correlation (r = 0.880, P < 0.001) was observed between magnitude (Diopsys®) and amplitude (Diagnosys®) measurements. Amplitude increases by 6.69 µV for each 1 µV increase in Magnitude (p-value < 0.001). A statistically significant, strong positive correlation was observed between Diopsys® implicit time measurements (converted from phase) and Diagnosys® implicit time measurements (r = 0.814, p-value < 0.001). For each 1 ms increase in Diopsys® implicit time, Diagnosys® implicit time increases by 1.13 ms (p-value < 0.001). CONCLUSIONS: There is a statistically significant positive correlation between light-adapted Diopsys® NOVA™ fixed-luminance flicker amplitude and Diagnosys® flicker magnitude values. Additionally, there is a statistically significant positive correlation between Diopsys® NOVA™ fixed-luminance flicker implicit time (converted from phase) and Diagnosys® flicker implicit time values. These results imply that the Diopsys® NOVA™ module, which utilizes the nonstandard shortened International Society for Clinical Electrophysiology of Vision (ISCEV) ERG protocol, can produce reliable light-adapted flicker ffERG measurements.

Pars plana vitrectomy with internal limiting membrane flap versus pars plana vitrectomy with conventional internal limiting membrane peeling for large macular hole.

BACKGROUND: Macular hole (MH) is a full-thickness defect in the central portion of the retina that causes loss of central vision. According to the usual definition, a large MH has a diameter greater than 400 µm at the narrowest point. For closure of MH, there is evidence that pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling achieves better anatomical outcomes than standard PPV. PPV with ILM peeling is currently the standard of care for MH management; however, the failure rate of this technique is higher for large MHs than for smaller MHs. Some studies have shown that the inverted ILM flap technique is superior to conventional ILM peeling for the management of large MHs. OBJECTIVES: To evaluate the clinical effectiveness and safety of pars plana vitrectomy with the inverted internal limiting membrane flap technique versus pars plana vitrectomy with conventional internal limiting membrane peeling for treating large macular holes, including idiopathic, traumatic, and myopic macular holes. SEARCH METHODS: The Cochrane Eyes and Vision Information Specialist searched CENTRAL, MEDLINE, Embase, two other databases, and two trials registries on 12 December 2022. SELECTION CRITERIA: We included randomized controlled trials (RCTs) that evaluated PPV with ILM peeling versus PPV with inverted ILM flap for treatment of large MHs (with a basal diameter greater than 400 µm at the narrowest point measured by optical coherence tomography) of any type (idiopathic, traumatic, or myopic). DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane and assessed the certainty of the body of evidence using GRADE. MAIN RESULTS: We included four RCTs (285 eyes of 275 participants; range per study 24 to 91 eyes). Most participants were women (63%), and of older age (range of means 59.4 to 66 years). Three RCTs were single-center trials, and the same surgeon performed all surgeries in two RCTs (the third single-center RCT did not report the number of surgeons). One RCT was a multicenter trial (three sites), and four surgeons performed all surgeries. Two RCTs took place in India, one in Poland, and one in Mexico. Maximum follow-up ranged from three months (2 RCTs) to 12 months (1 RCT). No RCTs reported conflicts of interest or disclosed financial support. All four RCTs enrolled people with large idiopathic MHs and compared conventional PPV with ILM peeling versus PPV with inverted ILM flap techniques. Variations in technique across the four RCTs were minimal. There was some heterogeneity in interventions: in two RCTs, all participants underwent combined cataract-PPV surgery, whereas in one RCT, some participants underwent cataract surgery after PPV (the fourth RCT did not mention cataract surgery). The critical outcomes for this review were mean best-corrected visual acuity (BCVA) and MH closure rates. All four RCTs provided data for meta-analyses of both critical outcomes. We assessed the risk of bias for both outcomes using the Cochrane risk of bias tool (RoB 2); there were some concerns for risk of bias associated with lack of masking of outcome assessors and selective reporting of outcomes in all RCTs. All RCTs reported postoperative BCVA values; only one RCT reported the change in BCVA from baseline. Based on evidence from the four RCTs, it is unclear if the inverted ILM flap technique compared with ILM peeling reduces (improves) postoperative BCVA measured on a logarithm of the minimum angle of resolution (logMAR) chart at one month (mean difference [MD] -0.08 logMAR, 95% confidence interval [CI] -0.20 to 0.05; P = 0.23, I2 = 65%; 4 studies, 254 eyes; very low-certainty evidence), but it may improve BCVA at three months or more (MD -0.17 logMAR, 95% CI -0.23 to -0.10; P < 0.001, I2 = 0%; 4 studies, 276 eyes; low-certainty evidence). PPV with an inverted ILM flap compared to PPV with ILM peeling probably increases the proportion of eyes achieving MH closure (risk ratio [RR] 1.10, 95% CI 1.02 to 1.18; P = 0.01, I2 = 0%; 4 studies, 276 eyes; moderate-certainty evidence) and type 1 MH closure (RR 1.31, 95% CI 1.03 to 1.66; P = 0.03, I² = 69%; 4 studies, 276 eyes; moderate-certainty evidence). One study reported that none of the 38 participants experienced postoperative retinal detachment. AUTHORS' CONCLUSIONS: We found low-certainty evidence from four small RCTs that PPV with the inverted ILM flap technique is superior to PPV with ILM peeling with respect to BCVA gains at three or more months after surgery. We also found moderate-certainty evidence that the inverted ILM flap technique achieves more overall and type 1 MH closures. There is a need for high-quality multicenter RCTs to ascertain whether the inverted ILM flap technique is superior to ILM peeling with regard to anatomical and functional outcomes. Investigators should use the standard logMAR charts when measuring BCVA to facilitate comparison across trials.