The Exonuclease TREX1 Constitutes an Innate Immune Checkpoint Limiting cGAS/STING-Mediated Antitumor Immunity.

The DNA exonuclease three-prime repair exonuclease 1 (TREX1) is critical for preventing autoimmunity in mice and humans by degrading endogenous cytosolic DNA, which otherwise triggers activation of the innate cGAS/STING pathway leading to the production of type I IFNs. As tumor cells are prone to aberrant cytosolic DNA accumulation, we hypothesized that they are critically dependent on TREX1 activity to limit their immunogenicity. Here, we show that in tumor cells, TREX1 restricts spontaneous activation of the cGAS/STING pathway, and the subsequent induction of a type I IFN response. As a result, TREX1 deficiency compromised in vivo tumor growth in mice. This delay in tumor growth depended on a functional immune system, systemic type I IFN signaling, and tumor-intrinsic cGAS expression. Mechanistically, we show that tumor TREX1 loss drove activation of CD8+ T cells and NK cells, prevented CD8+ T-cell exhaustion, and remodeled an immunosuppressive myeloid compartment. Consequently, TREX1 deficiency combined with T-cell-directed immune checkpoint blockade. Collectively, we conclude that TREX1 is essential to limit tumor immunogenicity, and that targeting this innate immune checkpoint remodels the tumor microenvironment and enhances antitumor immunity by itself and in combination with T-cell-targeted therapies. See related article by Toufektchan et al., p. 673.

Anti-TIGIT antibody improves PD-L1 blockade through myeloid and Treg cells.

Tiragolumab, an anti-TIGIT antibody with an active IgG1κ Fc, demonstrated improved outcomes in the phase 2 CITYSCAPE trial (ClinicalTrials.gov: NCT03563716 ) when combined with atezolizumab (anti-PD-L1) versus atezolizumab alone1. However, there remains little consensus on the mechanism(s) of response with this combination2. Here we find that a high baseline of intratumoural macrophages and regulatory T cells is associated with better outcomes in patients treated with atezolizumab plus tiragolumab but not with atezolizumab alone. Serum sample analysis revealed that macrophage activation is associated with a clinical benefit in patients who received the combination treatment. In mouse tumour models, tiragolumab surrogate antibodies inflamed tumour-associated macrophages, monocytes and dendritic cells through Fcγ receptors (FcγR), in turn driving anti-tumour CD8+ T cells from an exhausted effector-like state to a more memory-like state. These results reveal a mechanism of action through which TIGIT checkpoint inhibitors can remodel immunosuppressive tumour microenvironments, and suggest that FcγR engagement is an important consideration in anti-TIGIT antibody development.

Immunomodulatory effects and improved outcomes with cisplatin- versus carboplatin-based chemotherapy plus atezolizumab in urothelial cancer.

In metastatic urothelial cancer (mUC), cisplatin versus carboplatin leads to durable disease control in a subset of patients. The IMvigor130 trial reveals more favorable effects with atezolizumab combined with gemcitabine and cisplatin (GemCis) versus gemcitabine and carboplatin (GemCarbo). This study investigates the immunomodulatory effects of cisplatin as a potential explanation for these observations. Our findings indicate that improved outcomes with GemCis versus GemCarbo are primarily observed in patients with pretreatment tumors exhibiting features of restrained adaptive immunity. In addition, GemCis versus GemCarbo ± atezolizumab induces transcriptional changes in circulating immune cells, including upregulation of antigen presentation and T cell activation programs. In vitro experiments demonstrate that cisplatin, compared with carboplatin, exerts direct immunomodulatory effects on cancer cells, promoting dendritic cell activation and antigen-specific T cell killing. These results underscore the key role of immune modulation in cisplatin's efficacy in mUC and highlight the importance of specific chemotherapy backbones in immunotherapy combination regimens.

Patient-derived xenograft models of ALK+ ALCL reveal preclinical promise for therapy with brigatinib.

Anaplastic large-cell lymphoma (ALCL) is a T-cell malignancy predominantly driven by the oncogenic anaplastic lymphoma kinase (ALK), accounting for approximately 15% of all paediatric non-Hodgkin lymphoma. Patients with central nervous system (CNS) relapse are particularly difficult to treat with a 3-year overall survival of 49% and a median survival of 23.5 months. The second-generation ALK inhibitor brigatinib shows superior penetration of the blood-brain barrier unlike the first-generation drug crizotinib and has shown promising results in ALK+ non-small-cell lung cancer. However, the benefits of brigatinib in treating aggressive paediatric ALK+ ALCL are largely unknown. We established a patient-derived xenograft (PDX) resource from ALK+ ALCL patients at or before CNS relapse serving as models to facilitate the development of future therapies. We show in vivo that brigatinib is effective in inducing the remission of PDX models of crizotinib-resistant (ALK C1156Y, TP53 loss) ALCL and furthermore that it is superior to crizotinib as a second-line approach to the treatment of a standard chemotherapy relapsed/refractory ALCL PDX pointing to brigatinib as a future therapeutic option.

Single-cell transcriptome analysis of xenotransplanted human retinal organoids defines two migratory cell populations of nonretinal origin.

Human retinal organoid transplantation could potentially be a treatment for degenerative retinal diseases. How the recipient retina regulates the survival, maturation, and proliferation of transplanted organoid cells is unknown. We transplanted human retinal organoid-derived cells into photoreceptor-deficient mice and conducted histology and single-cell RNA sequencing alongside time-matched cultured retinal organoids. Unexpectedly, we observed human cells that migrated into all recipient retinal layers and traveled long distances. Using an unbiased approach, we identified these cells as astrocytes and brain/spinal cord-like neural precursors that were absent or rare in stage-matched cultured organoids. In contrast, retinal progenitor-derived rods and cones remained in the subretinal space, maturing more rapidly than those in the cultured controls. These data suggest that recipient microenvironment promotes the maturation of transplanted photoreceptors while inducing or facilitating the survival of migratory cell populations that are not normally derived from retinal progenitors. These findings have important implications for potential cell-based treatments of retinal diseases.

GIST-related malignant ascites with large-volume paracentesis complicated by myocardial infarction and tumour rupture.

This paper describes a patient with an inoperable gastrointestinal stromal tumour with moderate volume malignant ascites. A large-volume paracentesis caused haemodynamic instability and a myocardial infarction. An indwelling right-sided peritoneal catheter was inserted following further ascites build-up. The patient experienced spontaneous acute rupture of tumour and subsequent loculated ascites. An additional second catheter was inserted to the left side of the abdomen following reaccumulation of ascites following liquefaction of cyst contents and successful one-off drainage on the left side of abdomen. This is the first case report of a patient with two indwelling catheters: we describe learning points pertaining to those as well as the rupture of gastrointestinal stromal tumours. Haemodynamic instability after paracentesis in malignant-related ascites has also not been described.

Is 5q deletion in de novo Acute Myelogenous Leukemia (AML) with excess blasts a surrogate marker for the cryptic t(7;21)(p22;q22)? A case report and review of literature.

Although the 5q- syndrome is common in both de novo and treatment related myelodysplastic syndrome (MDS) and the World Health Organization defined 5q- syndrome as a specific type of MDS, it is less common in acute myelogenous leukemia (AML). Recently, it was suggested that AML with diploidy/tetraploidy and/or 5q alterations may be associated with the cryptic translocation, t(7;21)(p22;q22) resulting in RUNX1-USP42 gene fusion and this association may have been underestimated. Here, we report another case of de novo AML with cryptic t(7;21)(p22;q22) associated with a 5q deletion.

Methods for assessing seasonal and annual trends in wasting in Indian surveys (NFHS-3, 4, RSOC & CNNS).

Wasting in children under-five is a form of acute malnutrition, a predictor of under-five child mortality and of increased risk of future episodes of stunting and/or wasting. In India, national estimates of wasting are high compared to international standards with one in five children found to be wasted. National surveys are complex logistical operations and most often not planned or implemented in a manner to control for seasonality. Collection of survey data across differing months across states introduces seasonal bias. Cross-sectional surveys are not designed to collect data on seasonality, thus special methods are needed to analyse the effect of data collection by month. We developed regression models to estimate the mean weight for height (WHZ), prevalence of wasting for every month of the year for an average year and an overall weighted survey estimates controlling for the socio-demographic variation of data collection across states and populations over time. National level analyses show the mean WHZ starts at its highest in January, falls to the lowest in June/August and returns towards peak at year end. The prevalence of wasting is lowest in January and doubles by June/August. After accounting for seasonal patterns in data collection across surveys, the trends are significantly different and indicate a stagnant period followed by a decline in wasting. To avoid biased estimates, direct comparisons of acute malnutrition across surveys should not be made unless seasonality bias is appropriately addressed in planning, implementation or analysis. Eliminating the seasonal variation in wasting would reduce the prevalence by half and provide guidance towards further reduction in acute malnutrition.

Indwelling Peritoneal Catheter for Ascites Management in a UK District General Hospital: A Cohort Study.

BACKGROUND: There is no national or local guidance for management of malignancy-related ascites (MRA). Modalities can include large volume paracentesis (LVP) and indwelling peritoneal catheter (IPeC) insertion. OBJECTIVES: We set up a local IPeC service and performed a retrospective review with local ethical (Caldicott) approval. We hypothesized that an IPeC service would reduce inpatient stay related to MRA management, would be acceptable to patients, and have minimal complications. METHODS: Notes of all patients requiring IPeC insertion were reviewed. Descriptive statistical methodology was applied with continuous data presented as mean (standard deviation (SD); range) and categorical variables as frequencies or percentages. Integrated Palliative Care Outcome Scale (IPOS) scores were collected for IPeC patients. RESULTS: Thirty-four patients were identified. They were predominantly female, with a mean age of 66.6 years and a wide range of cancer diagnoses. Twenty-nine were inserted as day case procedures, and 31 had preceding paracenteses (mean 2). Main complications were leakage (6(17%)), peritonitis (2(5.8%)), and skin infection (1(3%)). IPOS scores showed consistent improvement in symptoms. CONCLUSIONS: An IPeC service for malignant-related ascites is acceptable to patients and is associated with manageable complication rates. We present the development of our service and hope for widespread application.

Pluripotent stem cell therapy for retinal diseases.

Pluripotent stem cells (PSCs), which include human embryonic stem cells (hESCs) and induced pluripotent stem cell (iPSC), have been used to study development of disease processes, and as potential therapies in multiple organ systems. In recent years, there has been increasing interest in the use of PSC-based transplantation to treat disorders of the retina in which retinal cells have been functionally damaged or lost through degeneration. The retina, which consists of neuronal tissue, provides an excellent system to test the therapeutic utility of PSC-based transplantation due to its accessibility and the availability of high-resolution imaging technology to evaluate effects. Preclinical trials in animal models of retinal diseases have shown improvement in visual outcomes following subretinal transplantation of PSC-derived photoreceptors or retinal pigment epithelium (RPE) cells. This review focuses on preclinical studies and clinical trials exploring the use of PSCs for retinal diseases. To date, several phase I/II clinical trials in patients with age-related macular degeneration (AMD) and Stargardt disease (STGD1) have demonstrated the safety and feasibility of PSC-derived RPE transplantation. Additional phase I/II clinical trials using PSC-derived RPE or photoreceptor cells for the treatment of AMD, STGD1, and also retinitis pigmentosa (RP) are currently in the pipeline. As this field continues to evolve, additional technologies may enhance PSC-derived cell transplantation through gene-editing of autologous cells, transplantation of more complex cellular structures such as organoids, and monitoring of transplanted cells through novel imaging technologies.

Prevalence of Iron Deficiency and its Sociodemographic Patterning in Indian Children and Adolescents: Findings from the Comprehensive National Nutrition Survey 2016-18.

BACKGROUND: Anemia control programs in India focus mainly on the measurement of hemoglobin in response to iron-folic acid supplementation. However, representative national estimates of iron deficiency (ID) are not available. OBJECTIVES: The objective of the present study was to evaluate ID prevalence among children and adolescents (1-19 y) using nationally representative data and to examine the sociodemographic patterning of ID. METHODS: Cross-sectional data from the Comprehensive National Nutrition Survey in children (1-4 y: n = 9635; 5-9 y: n = 11,938) and adolescents (10-19 y; n = 11,507) on serum ferritin (SF) and other biomarkers were analyzed to determine inflammation-adjusted ID prevalence [SF (µg/L): <12 in 1-4 y and <15 in 5-19 y] and its relation to sociodemographic indicators. Multiple-regression analyses were conducted to identify the exposure associations of iron status. In addition, the relation between SF and hemoglobin was assessed as an indicator of iron utilization in different wealth quintiles. RESULTS: ID prevalence was higher in 1- to 4-y-old children (31.9%; 95% CI: 31.0%, 32.8%) and adolescent girls (30.4%; 95% CI: 29.3%, 31.5%) but lower in adolescent boys and 5- to 9-y-old children (11%-15%). In all age groups, ID prevalence was higher in urban than in rural participants (1-4 y: 41% compared with 29%) and in those from richer quintiles (1-4 y: 44% in richest compared with 22% in poorest), despite adjustment for relevant confounders. SF significantly interacted with the wealth index, with declining trends in the strength of association between hemoglobin and SF from the richest to the poorest groups suggesting impaired iron utilization for hemoglobin synthesis in poorer wealth quintiles. CONCLUSIONS: ID prevalence was indicative of moderate (in preschool children and adolescent girls) or mild (in 5- to 9-y-old children and adolescent boys) public health problem with significant variation by state and age. Focusing on increasing iron intake alone, without addressing the multiple environmental constraints related to poverty, may not result in intended benefits.

Characterization of histone inheritance patterns in the Drosophila female germline.

Stem cells have the unique ability to undergo asymmetric division which produces two daughter cells that are genetically identical, but commit to different cell fates. The loss of this balanced asymmetric outcome can lead to many diseases, including cancer and tissue dystrophy. Understanding this tightly regulated process is crucial in developing methods to treat these abnormalities. Here, we report that during a Drosophila female germline stem cell asymmetric division, the two daughter cells differentially inherit histones at key genes related to either maintaining the stem cell state or promoting differentiation, but not at constitutively active or silenced genes. We combine histone labeling with DNA Oligopaints to distinguish old versus new histones and visualize their inheritance patterns at a single-gene resolution in asymmetrically dividing cells in vivo. This strategy can be applied to other biological systems involving cell fate change during development or tissue homeostasis in multicellular organisms.

The value of bronchoscopy in patients with non-massive haemoptysis and a clear or benign computer tomogram scan.

INTRODUCTION: The preferred diagnostic pathway for patients presenting with non-massive haemoptysis and normal or benign computer tomography (CT) radiological findings is unclear. The common approach is to investigate with both CT and bronchoscopy, irrespective of patient-specific factors. The value of performing fibreoptic bronchoscopy (FOB) in patients with non-massive haemoptysis and clear or benign CT findings remains undetermined. We aimed to investigate its value using a large retrospective case series. MATERIAL AND METHODS: A retrospective review of 4376 FOBs performed in Northumbria Healthcare NHS Foundation Trust from January 2012 to December 2019 for patients presenting with haemoptysis and clear or benign CT findings. Statistical analysis was performed to describe patient-specific variables, clinical characteristics, pathological findings and subsequent management decisions. RESULTS: A total of 4376 FOBs were performed during the study period, 275 were indicated to investigate non-massive haemoptysis. Two hundred and fifty-nine patients underwent a CT scan (158 before and 101 after FOB); 16 never had a CT because the treating physician did not feel it was necessary. About 258 CT scans showed normal anatomy. All patients underwent FOB; 192 showed normal findings. Bronchoscopic findings did not alter clinical management in 274 patients. One patient was referred to the ear, nose and throat department following the identification of polypoid vocal cord lesion which, following thorough investigation, was confirmed as benign. CONCLUSION: FOB provides minimal value for identifying lung malignancies in patients with non-massive haemoptysis and a clear or benign CT scan irrespective of patient-specific risk factors. Cost savings would be associated if physicians altered practice accordingly.

CD155 on Tumor Cells Drives Resistance to Immunotherapy by Inducing the Degradation of the Activating Receptor CD226 in CD8+ T Cells.

The activating receptor CD226 is expressed on lymphocytes, monocytes, and platelets and promotes anti-tumor immunity in pre-clinical models. Here, we examined the role of CD226 in the function of tumor-infiltrating lymphocytes (TILs) and resistance to immunotherapy. In murine tumors, a large proportion of CD8+ TILs had decreased surface expression of CD226 and exhibited features of dysfunction, whereas CD226hi TILs were highly functional. This correlation was seen also in TILs isolated from HNSCC patients. Mutation of CD226 at tyrosine 319 (Y319) led to increased CD226 surface expression, enhanced anti-tumor immunity and improved efficacy of immune checkpoint blockade (ICB). Mechanistically, tumor-derived CD155, the ligand for CD226, initiated phosphorylation of Y319 by Src kinases, thereby enabling ubiquitination of CD226 by CBL-B, internalization, and proteasomal degradation. In pre-treatment samples from melanoma patients, CD226+CD8+ T cells correlated with improved progression-free survival following ICB. Our findings argue for the development of therapies aimed at maintaining the expression of CD226.

Osteopathic Manual Treatment for Pain Severity, Functional Improvement, and Return to Work in Patients With Chronic Pain.

CONTEXT: Chronic non-cancer pain (CNCP) is associated with disability, poor quality of life (QOL), and failure to return to work (RTW). Osteopathic manipulative treatment (OMT) or osteopathic manual therapy (OMTh) are increasingly offered to patients with CNCP; however, the existing systematic reviews and meta-analyses in the literature that explore the effectiveness of OMTh have major limitations. OBJECTIVE: To systematically evaluate the quality of evidence documenting the effectiveness of OMTh for patients with CNCP using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and to evaluate the efficacy of OMTh in patients with CNCP through a meta-analysis of pooled data from previous studies. METHODS: We searched online the databases Ovid, MEDLINE, Embase, OSTMED.DR, EMCare, Allied and Complementary Medicine Database (AMED), Physiotherapy Evidence Database (PEDro), and Cochrane Central Register of Controlled Trials (CENTRAL), as well as the bibliographic references of previous systematic review articles evaluating OMTh for pain severity, disability, QOL, or RTW outcomes. Eligibility included randomized controlled trials methodology, CNCP patients 18 years or older, use of previously validated assessment tools, use of OMTh as an active or combination intervention, and presence of a control or comparison group. We pooled studies based on the homogeneity between OMT comparator treatment and outcomes. Risk of bias was assessed with the Cochrane risk of bias tool and the quality of evidence was determined with GRADE. RESULTS: Sixteen randomized controlled trials (n=1158 patients) were eligible for data extraction. Moderate quality evidence showed that OMTh vs. standard care was significantly associated with a reduction in pain [standardized mean difference (95% CI)=[-.37 (-.58, -.17)] and disability [-.28 (-.46, -.10)], as well as improved QOL [.67 (.29, 1.05)]. Moderate quality evidence showed that OMTh plus exercise vs. exercise only was significantly associated with reduction in pain severity [-1.25 (-1.67, -.83)] and disability [-1.15 (-1.57, -.74)]. Moderate quality evidence showed that using visceral OMTh vs. general OMTh was significantly associated with reduction in pain severity [-.74 (-1.09, -.39)] and disability [-.52 (-.91, -.13)]. In comparison to physiotherapy, gabapentin, and OMTh plus gabapentin, OMTh did not show any significant effect for any of the outcomes. OMTh vs. standard care did not show significant improvement in RTW at 12 weeks, although the effect was significant at 8 weeks after OMTh. CONCLUSION: Moderate quality evidence suggests that OMTh is effective for CNCP patients. There was a significant association between visceral OMTh and reduced pain severity and disability. More robust, high-quality randomized controlled trials with larger sample sizes are required to further explore the effectiveness of the OMTh in the management of CNCP.

IL15 Stimulation with TIGIT Blockade Reverses CD155-mediated NK-Cell Dysfunction in Melanoma.

PURPOSE: Natural killer (NK) cells play a critical role in tumor immunosurveillance. Multiple activating and inhibitory receptors (IR) regulate NK-cell-mediated tumor control. The IR T-cell immunoglobulin and ITIM domain (TIGIT) and its counter-receptor CD226 exert opposite effects on NK-cell-mediated tumor reactivity. EXPERIMENTAL DESIGN: We evaluated the frequency, phenotype, and functions of NK cells freshly isolated from healthy donors and patients with melanoma with multiparameter flow cytometry. We assessed TIGIT and CD226 cell surface expression and internalization upon binding to CD155. We evaluated the role of IL15 and TIGIT blockade in increasing NK-cell-mediated cytotoxicity in vitro and in two mouse models. RESULTS: NK cells are present at low frequencies in metastatic melanoma, are dysfunctional, and downregulate both TIGIT and CD226 expression. As compared with TIGIT- NK cells, TIGIT+ NK cells exhibit higher cytotoxic capacity and maturation, but paradoxically lower cytotoxicity against CD155+ MHC class I-deficient melanoma cells. Membrane bound CD155 triggers CD226 internalization and degradation, resulting in decreased NK-cell-mediated tumor reactivity. IL15 increases TIGIT and CD226 gene expression by tumor-infiltrating NK cells (TiNKs) and, together with TIGIT blockade, increases NK-cell-mediated melanoma cytotoxicity in vitro and decreases tumor metastasis in two mouse melanoma models. Specific deletion of TIGIT on transferred NK cells enhances the antimetastatic activity of IL15, while CD226 blockade decreases the effects of IL15 and TIGIT blockade. CONCLUSIONS: Our findings support the development of novel combinatorial immunotherapy with IL15 and TIGIT blockade to promote NK-cell-mediated destruction of MHC class I-deficient melanoma, which are refractory to CD8+ T-cell-mediated immunity.See related commentary by Pietra et al., p. 5274.

A conserved intratumoral regulatory T cell signature identifies 4-1BB as a pan-cancer target.

Despite advancements in targeting the immune checkpoints program cell death protein 1 (PD-1), programmed death ligand 1 (PD-L1), and cytotoxic T lymphocyte-associated protein 4 (CTLA-4) for cancer immunotherapy, a large number of patients and cancer types remain unresponsive. Current immunotherapies focus on modulating an antitumor immune response by directly or indirectly expanding antitumor CD8 T cells. A complementary strategy might involve inhibition of Tregs that otherwise suppress antitumor immune responses. Here, we sought to identify functional immune molecules preferentially expressed on tumor-infiltrating Tregs. Using genome-wide RNA-Seq analysis of purified Tregs sorted from multiple human cancer types, we identified a conserved Treg immune checkpoint signature. Using immunocompetent murine tumor models, we found that antibody-mediated depletion of 4-1BB-expressing cells (4-1BB is also known as TNFRSF9 or CD137) decreased tumor growth without negatively affecting CD8 T cell function. Furthermore, we found that the immune checkpoint 4-1BB had a high selectivity for human tumor Tregs and was associated with worse survival outcomes in patients with multiple tumor types. Thus, antibody-mediated depletion of 4-1BB-expressing Tregs represents a strategy with potential activity across cancer types.

The Royal College of Ophthalmologists' National Ophthalmology Database study of cataract surgery: report 4, equity of access to cataract surgery.

OBJECTIVE: To determine whether socioeconomic status influenced the presenting visual acuity prior to first eye cataract surgery in the English National Health Service. Retrospective case series from The Royal College of Ophthalmologists' National Ophthalmology Database Audit. In total 154,223 patients undergoing first eye cataract surgery at 68 centres in England performed between 1st September 2015 and 31st August 2017. MAIN OUTCOME MEASURE: Social deprivation status and pre-operative visual acuity (VA) between centres for patients undergoing first eye cataract surgery in England. RESULTS: The median social deprivation varied between centres and ranged from decile 2 (2nd most deprived decile) to decile 9 (2nd least deprived decile). The pre-operative VA was reported for 143,401 (93.0%) eyes. The median pre-operative VA was 0.50 LogMAR (6/19), and 27.7% eyes had a preoperative VA of 0.30 LogMAR units (6/12) or better. The median pre-operative VA for each centre ranged from 0.30 to 0.60 LogMAR (6/12 to 6/24). The median pre-operative VA was mostly stable across deciles of social deprivation (0.60 LogMAR for decile 1 and 0.50 LogMAR for all other deciles), and some evidence was found linking greater deprivation to worse pre-operative VA and to lower levels of access. CONCLUSIONS: We found no strong evidence of inequality for gaining access to first eye cataract surgery in this National Ophthalmology Database analysis, however there was a possible trend towards fewer people in the more deprived deciles accessing surgery, and that some of these are presenting with quite marked levels of visual impairment.

Royal College of Ophthalmologists' National Ophthalmology Database study of cataract surgery: report 6. The impact of EyeSi virtual reality training on complications rates of cataract surgery performed by first and second year trainees.

OBJECTIVE: To investigate the impact of EyeSi surgical simulators on posterior capsule rupture (PCR) rates of cataract surgery performed by first and second year trainee surgeons. DESIGN: A Royal College of Ophthalmologists' National Ophthalmology Database audit study of first and second year surgeons' PCR rates over seven consecutive National Health Service (NHS) years. Participating centres were contacted to ascertain the date when their surgeons had access to an EyeSi machine and whether this was on-site or off-site. Operations were classified as before, after or no access to EyeSi. SETTING: The study took place in 29 NHS Ophthalmology Units in a secondary care setting. RESULTS: Two-hundred and sixty five first and second year trainee surgeons performed 17 831 cataract operations. 6919 (38.8%) operations were performed before access to an EyeSi, 8648 (48.5%) after access to an EyeSi and 2264 (12.7%) operations by surgeons with no access to an EyeSi. Overall, there was a 38% reduction in the first and second year surgeon's unadjusted PCR rates from 4.2% in 2009 to 2.6% in 2015 for surgeons with access to an EyeSi, and a 3% reduction from 2.9% to 2.8% for surgeons without access to an EyeSi. The overall first and second year unadjusted PCR rates for before, after and no access to EyeSi were 3.5%, 2.6% and 3.8%, respectively. The decrease in the with-access to an EyeSi group PCR rate was similar for surgeons with access to an EyeSi 'on site' or 'off site'. CONCLUSIONS: First and second year trainee surgeons' unadjusted PCR rates have decreased since 2009 which has significant benefits for patients undergoing cataract surgery. This 38% reduction in complication rates aligns with the introduction of EyeSi simulator training.