3D Lung Tissue Models for Studies on SARS-CoV-2 Pathophysiology and Therapeutics.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing the coronavirus disease 2019 (COVID-19), has provoked more than six million deaths worldwide and continues to pose a major threat to global health. Enormous efforts have been made by researchers around the world to elucidate COVID-19 pathophysiology, design efficacious therapy and develop new vaccines to control the pandemic. To this end, experimental models are essential. While animal models and conventional cell cultures have been widely utilized during these research endeavors, they often do not adequately reflect the human responses to SARS-CoV-2 infection. Therefore, models that emulate with high fidelity the SARS-CoV-2 infection in human organs are needed for discovering new antiviral drugs and vaccines against COVID-19. Three-dimensional (3D) cell cultures, such as lung organoids and bioengineered organs-on-chips, are emerging as crucial tools for research on respiratory diseases. The lung airway, small airway and alveolus organ chips have been successfully used for studies on lung response to infection by various pathogens, including corona and influenza A viruses. In this review, we provide an overview of these new tools and their use in studies on COVID-19 pathogenesis and drug testing. We also discuss the limitations of the existing models and indicate some improvements for their use in research against COVID-19 as well as future emerging epidemics.

CFTR Modulation Reduces SARS-CoV-2 Infection in Human Bronchial Epithelial Cells.

People with cystic fibrosis should be considered at increased risk of developing severe symptoms of COVID-19. Strikingly, a broad array of evidence shows reduced spread of SARS-CoV-2 in these subjects, suggesting a potential role for CFTR in the regulation of SARS-CoV-2 infection/replication. Here, we analyzed SARS-CoV-2 replication in wild-type and CFTR-modified human bronchial epithelial cell lines and primary cells to investigate SARS-CoV-2 infection in people with cystic fibrosis. Both immortalized and primary human bronchial epithelial cells expressing wt or F508del-CFTR along with CRISPR/Cas9 CFTR-ablated clones were infected with SARS-CoV-2 and samples were harvested before and from 24 to 72 h post-infection. CFTR function was also inhibited in wt-CFTR cells with the CFTR-specific inhibitor IOWH-032 and partially restored in F508del-CFTR cells with a combination of CFTR modulators (VX-661+VX-445). Viral load was evaluated by real-time RT-PCR in both supernatant and cell extracts, and ACE-2 expression was analyzed by both western blotting and flow cytometry. SARS-CoV-2 replication was reduced in CFTR-modified bronchial cells compared with wild-type cell lines. No major difference in ACE-2 expression was detected before infection between wild-type and CFTR-modified cells, while a higher expression in wild-type compared to CFTR-modified cells was detectable at 72 h post-infection. Furthermore, inhibition of CFTR channel function elicited significant inhibition of viral replication in cells with wt-CFTR, and correction of CFTR function in F508del-CFTR cells increased the release of SARS-CoV-2 viral particles. Our study provides evidence that CFTR expression/function is involved in the regulation of SARS-CoV-2 replication, thus providing novel insights into the role of CFTR in SARS-CoV-2 infection and the development of therapeutic strategies for COVID-19.

MYTHS AND TRUTHS OF THE ASSOCIATION OF RETINAL VASCULAR OCCLUSION WITH COVID-19.

PURPOSE: To critically review data published in the recent past to scrutinize a causal relationship between retinal vascular occlusion and COVID-19. METHOD: A comprehensive literature search was performed on Pubmed with the key words retinal vascular occlusion, retinal vein occlusion, retinal artery occlusion, and COVID-19. RESULTS: A total of 17 case reports were published during this period, and 10 were on retinal vein occlusion and 7 on retinal artery occlusion. Most of the published reports lacked convincing evidences in one or the other aspects, such as insufficient laboratory workup or presence of multiple confounding risk factors. CONCLUSION: In this index article, strength of the data is insufficient to establish a definitive cause-and-effect relationship of retinal vascular occlusive disorders with COVID-19. Hence, clinicians can continue to manage these cases according to the standard guidelines until there are more robust evidences to support this association to alter the diagnostic and treatment modalities.

Short-Term Outcomes After COVID-19-Related Treatment Interruption Among Patients with Neovascular Age-Related Macular Degeneration Receiving Intravitreal Bevacizumab.

PURPOSE: To assess outcomes and recovery strategy of patients undergoing intravitreal injections for exudative age-related macular degeneration who experienced COVID-19 related interruption in treatment during complete lockdown. METHODS: This was a retrospective, observational case study. We used a mixed effect model with random intercepts to evaluate best corrected visual acuity (BCVA) accounting for measured central macular thickness (CMT) and individual variability of each eye. Furthermore, we analysed measures of the pigmented epithelium detachment as well as presence of subretinal fluid and intraretinal cysts. RESULTS: We included 39 patients and we found a significant reduction in the BCVA between the pre- and post-lockdown controlling for CMT. There was no significant difference in pigmented epithelium detachment and in presence of subretinal fluid and intraretinal cysts. CONCLUSION: We detected a significant loss in visual function. The magnitude of the average loss was, however, limited suggesting good efficacy of the recovery strategy.

Resolvin D1 and D2 reduce SARS-CoV-2-induced inflammatory responses in cystic fibrosis macrophages.

An excessive, non-resolving inflammatory response underlies severe COVID-19 that may have fatal outcomes. Therefore, the investigation of endogenous pathways leading to resolution of inflammation is of interest to uncover strategies for mitigating inflammation in people with SARS-CoV-2 infection. This becomes particularly urgent in individuals with preexisting pathologies characterized by chronic respiratory inflammation and prone to bacterial infection, such as cystic fibrosis (CF). Here, we analyzed the immune responses to SARS-CoV-2 virion spike 1 glycoprotein (S1) of macrophages (MΦ) from volunteers with and without CF and tested the efficacy of resolvins (Rv) D1 and D2 in regulating the inflammatory and antimicrobial functions of MΦ exposed to S1. S1 significantly increased chemokine release, including interleukin (IL)-8, in CF and non-CF MΦ, while it enhanced IL-6 and tumor necrosis factor (TNF)-α in non-CF MΦ, but not in CF cells. S1 also triggered the biosynthesis of RvD1 and modulated microRNAs miR-16, miR-29a, and miR-103, known to control the inflammatory responses. RvD1 and RvD2 treatment abated S1-induced inflammatory responses in CF and non-CF MΦ, significantly reducing the release of select chemokines and cytokines including IL-8 and TNF-α. RvD1 and RvD2 both restored the expression of miR-16 and miR-29a, while selectively increasing miR-223 and miR-125a, which are involved in NF-κB activation and MΦ inflammatory polarization. During Pseudomonas aeruginosa infection, S1 stimulated the MΦ phagocytic activity that was further enhanced by RvD1 and RvD2. These results provide a map of molecular responses to SARS-CoV-2 in MΦ, key determinants of COVID-19-related inflammation, unveiling some peculiarity in the response of cells from individuals with CF. They also demonstrate beneficial, regulatory actions of RvD1 and RvD2 on SARS-CoV-2-induced inflammation.

Covid-19 and acute conjunctivitis: Controversial data from a tertiary refferral Italian center.

PURPOSE: Although acute conjunctivitis has been listed from the beginning as a possible sign of COVID-19, the likelihood of this association remains unclear. The aim of this study was to investigate the relationship between COVID-19 and conjunctivitis. METHODS: In this retrospective, observational study, we recruited all patients with signs and symptoms of acute conjunctivitis seen at the Eye Emergency Department (ED), Turin Eye Hospital, between 01/01/2020 and 12/05/2020 and cross-checked our data with the Piedmont Region online COVID-19 registry in the same period. RESULTS: Among 10,065 patients seen at our ED during the timespan considered, 88 underwent a nasopharyngeal swab (NS) for SARS-CoV-2 detection within 4 weeks before/after our examination. On average, NS was performed -0.72 ± 1.8 weeks before/after eye examination. Of the 77 patients with a negative NS, 26 (33.8%) had a diagnosis of acute conjunctivitis, whereas the remaining 51 (66.2%) had other eye disorders. Among the 11 patients with COVID-19, 7 (63,6%) had a diagnosis of acute conjunctivitis. We found a non-statistically significant increase in NS positivity rate (21.2%) among cases examined at our ED for acute conjunctivitis, compared to the NS positivity rate (7.3%) in patients examined for all other eye conditions (p = 0.092). The Odds Ratio of having a positive NS in patients with acute conjunctivitis was 3.43 (95% I.C. = 0.9-12.8, p = 0.06). Considering online-registry data of Turin population during the same time-span, among 2441 positive NS cases only 27 (1.1%) presented with acute conjunctivitis. CONCLUSION: Our results do not reveal a statistically significant correlation between COVID-19 and acute conjunctivitis. SYNOPSIS: The present study analyzes retrospectively data from a tertiary eye referral center to investigate the relationship between COVID-19 infection and conjunctivitis.

Air contamination inside an actual operating room due to ultrafine particles

Hospital Operating Rooms (ORs) are working spaces which demand an utmost clean air environment for enhancing both the safety and the comfort conditions of medical staff and patients, in order to reduce the risk of post-operative complications. In this context, an integrated experimental-numerical study has been carried out in the present work, to investigate air contamination due to UltraFine Particles (UFPs) inside an actual, but unoccupied, OR, equipped with a laminar air flow system, located near Milan in Northern Italy. The UFPs considered in the present study are geometrically representative of surgical smoke and SARS-CoV, SARS-CoV-2 (COVID-19) virus particles. The flow and thermal fields in the OR have been calculated by using the Realizable k-ε turbulence model. A transient passive scalar species transport equation, based on the drift flux model, has been implemented along with the particle deposition boundary conditions at the OR walls, to analyse the UFPs concentration within the OR. The numerical model has been used, after validation against experimental data, to reproduce the quantities of interest in the OR. Moreover, type A and type B uncertainties have been associated to the experimental measurements. The velocity and temperature fields in the OR, obtained from both the numerical and experimental analysis, are compliant to the technical standards. A good agreement is observed between experimental and numerical results, in terms of velocity, temperature and UFPs concentration. A time of 19 minutes to completely evacuate UFPs from the OR has been obtained from both experimental and numerical analysis, with a deviation smaller than 2% between the results.

Implementing the new normal in ophthalmology care beyond COVID-19.

The COVID-19 pandemic has altered the clinical landscape immeasurably. The need to physical distance requires rethinking how we deliver ophthalmic care. Within healthcare, we will need to focus our resources on the five T's: Utilising technology, multidisciplinary clinical teams with wide professional talents need to work efficiently to reduce patient contact time. With regular testing, this will allow us to reduce the risk further. We also must acknowledge the explosion of different modalities to train our future ophthalmologists and the global challenges and advantages that these bring. Finally, we must not forget the psychological impact that this pandemic will have on ophthalmologists and ancillary staff, and need to have robust mechanisms for support.

Effects of the first month of lockdown for COVID-19 in Italy: A preliminary analysis on the eyecare system from six centers.

PURPOSE: To compare the number of eye surgical procedures performed in Italy during the first month of lockdown with those performed in the same period in 2019. METHODS: Review of the surgical procedures performed from 10 March to 9 April 2019 and from 10 March to 9 April 2020 (the first month of lockdown because of the COVID-19 outbreak) at six academic institutional centers of Italy. A distinction was made between urgent procedures: any trauma repairment, trabeculectomy/drainage implant for glaucoma, any operation for rhegmatogenous retinal detachment (RRD) repair, pars plana vitrectomy (PPV) for vitreous hemorrhage (VH), macular hole, or retained lens fragments; elective procedures: corneal transplant, phacoemulsification for cataract extraction, silicone oil removal, and PPV for epiretinal membrane; and intravitreal injections (either anti-vascular endothelial growth factor [VEGF] or dexamethasone) to treat exudative maculopathies. The main outcome measure was the rate of reduction in urgent and elective surgeries performed. RESULTS: Overall, 3624 and 844 surgical procedures were performed from 10 March to 9 April 2019 and from 10 March to 10 April 2020, respectively (-76.7% in 2020 compared to 2019, p < 0.0001). Urgent and elective surgical procedures and intravitreal injections of anti-VEGF drugs or dexamethasone reduced significantly in 2020 in comparison to 2019 (p < 0.0001 for urgent and elective surgeries and 0.01 for intravitreal injections). CONCLUSION: A significant reduction in the rate of urgent and elective surgeries and intravitreal injections was recorded during the first month of lockdown compared to the same period in 2019. With this analysis, the authors hope to provide some preliminary insights about the consequences of lockdown for the eyecare system in Italy.

The use of personal protective equipment in clinical ophthalmology during corona virus disease-2019: a review of international guidelines and literature.

PURPOSE OF REVIEW: The use of nonpharmaceutical interventions can prevent viral spread in COVID-19 pandemic and PPE forms a crucial part of this strategy. However, there are discrepancies in existing guidelines and a lack of consensus among ophthalmic communities. This review aims to identify general consensus and provides recommendation of PPE for most common ophthalmological scenarios. With a global shortage of PPE, extended use and reuse strategies are also discussed. RECENT FINDINGS: In this review, guidelines and resources were selected, based on a three-tier process. The first-tier resources were from international infection control organizations. The second-tier resources were from ophthalmological professional associations and colleges. The third-tier resources involved a PubMed search using the keywords 'COVID-19; coronavirus; personal protective equipment' performed on 1 May 2020. Non-English guidelines and literatures were excluded. SUMMARY: On the basis of our methodology, we included a total of 30 documents, including 5 resources from tier 1, 14 resources from tier 2 and 15 from tier 3. Different levels of protection are necessary. Whenever performing an aerosol generating procedure, maximum protection should be ensured, this includes FFP3 respirator, fluid resistant gown, goggles or face-shield and disposable gloves. Similar protection should be used for handling COVID-19-positive/suspected case but the use of FFP2 respirator is acceptable. During routine outpatient clinic in cases of negative triage, it is recommended to use ASTM III surgical mask, plastic apron, disposable gloves and eye protection with goggles or face-shield. Lastly, patients should be encouraged to wear surgical masks whenever possible.

Reshaping ophthalmology training after COVID-19 pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has had a significant impact on practical activities and didactic teaching of residents and fellows. This survey aimed to propose long-term changes for ophthalmology training based on the changes experienced by trainees and their perception of new training opportunities. METHODS: An online survey was distributed to ophthalmology trainees in multiple countries. Descriptive statistics were used to analyse the data. RESULTS: A total of 504 analyzable responses were collected from 32 different countries. The current impact of COVID-19 pandemic was described as "severe" by most trainees (55.2%); however, the future perspective was more optimistic as demonstrated by the greater number of responses reporting a presumed "moderate" (37.3%), "mild" (14.1%) or "slight" (4.2%) long-term impact. The vast majority of trainees reported a decrease ≥50% of clinical activity (76.4%) and >75% of surgical activity (74.6%). Although an initial gap in didactic teaching has been experienced by many (55.4%), regular web-based teaching was reportedly attended by 67.7% of the respondents. A strong agreement was found regarding the worthwhile role of web-based case-presentations in clinical training (91.7%), web-based discussion of edited surgical videos (85.7%) and simulation-based practice (86.9%) in surgical training. CONCLUSIONS: This survey, focusing on trainees' perspective, strongly reinforces the need to promptly include new technology-based training tools, such as web-based teaching, virtual surgical simulators, and telementoring, in long-term reorganisation of ophthalmology training to ensure its continuity and effectiveness, which would remain available even in the face of another unpredictable crisis within the health system.

Facing COVID-19 in Ophthalmology Department.

Purpose: To provide useful guidelines, targeted at ophthalmology professionals, to minimize COVID-19 infection of both health-care workers and patients.Methods: In this review we present updated literature merged with our experience from hospitals in Bergamo, the epicenter of the COVID-19 European outbreak.Results: Non-pharmaceutical interventions, hygienic recommendations and personal protective equipment to contain viral spread as well as a suggested risk assessment for postponement of non-urgent cases should be applied in ophthalmologist activity. A triage for ophthalmic outpatient clinic is mandatory.Conclusion: Ophthalmology practice should be reorganized in order to face COVID-19.