The COVID-19 pandemic and clinical characteristics of colorectal cancer: a multicenter retrospective study (preprint)

Purpose. The spread of COVID-19 has led to numerous hospitals prioritizing case management and to delays in diagnosis and treatment. Consequently, many cancer patients have developed life-threatening complications during the COVID-19 pandemic. The aim of this study was to investigate the impact of COVID-19 pandemic on colorectal cancer (CRC), including its clinical and pathologic characteristics.Methods. This multicenter cohort study was performed at six institutions in Korea and included a total of 3871 patients with CRC treated between March 2019 and February 2021. After exclusion of 211 patients who did not undergo surgery, the data of 3660 patients were compared 1 year before and after the COVID-19 pandemic. The patients’ baseline characteristics, CRC-related complications, perioperative outcomes including emergency surgery, R0 resection rates, stoma formations, postoperative complications, and pathologic outcomes were assessed.Results. The number of patients decreased during the pandemic (− 18.0%, from 2127 to 1744), but the baseline characteristics did not differ. The pandemic group had greater disease severity given the presence of bleeding, perforation, and obstruction as complications (9.8% vs. 12.7%, P = 0.033). The proportion of patients who had open surgery (15.9% vs. 17.6%, P = 0.049), stoma formation (11.9% vs. 15.4%, P < 0.001), early postoperative complications (13.5% vs. 17.5%, P = 0.001), and adjuvant chemotherapy increased in the pandemic group (45.5% vs. 50.1%, P = 0.003).Conclusion. The clinical and pathologic features of CRC partly worsened during the pandemic. Healthcare providers and governments should prepare to encounter patients with CRC having poor clinical features for years and encourage people to participate in cancer screening programs.Trial registration: The Clinical Research Information Service (No. KCT0008063), January 2, 2023, retrospectively registered.

An engineered A549 cell line expressing CD13 and TMPRSS2 is permissive to clinical isolate of human coronavirus 229E (preprint)

Many viruses are well adapted to in vivo conditions but perform poorly in vitro, requiring extensive cell culture adaptation and directed evolution. Coronaviruses are indifferent, and the lack of suitable in vitro culture models delayed or hampered research on wild-type (WT) human coronaviruses for years. While 3D tissue or organ cultures have been instrumental for this purpose, such models are challenging, time-consuming, expensive, and require advanced cell culture expertise. Consequently, high-throughput applications are beyond reach in most cases. Here we developed a robust A549 cell line permissive to human coronavirus 229E (HCoV-229E) clinical isolates by transducing CD13 and transmembrane serine protease 2 (TMPRSS2), henceforth referred to as A549++ cells. This modification allowed for productive infection and resulted in syncytia formation in infected A549++ cells. Moreover, a more detailed analysis showed that the virus might use the TMPRSS2-dependent pathway but can still bypass this pathway using the cathepsin-mediated, endocytosis-dependent route. Overall, our data showed that A549++ cells are permissive to HCoV-229E clinical isolate and can be used for antiviral drug screening and further studies on HCoV-229E clinical isolate infection biology. Moreover, this line constitutes a uniform platform for studies on multiple members of the Coronaviridae family.

Metalloproteinase-dependent and TMPRSS2-independnt cell surface entry pathway of SARS-CoV-2 requires the furin-cleavage site and the S2 domain of spike protein (preprint)

The ongoing global vaccination program to prevent SARS-CoV-2 infection, the causative agent of COVID-19, has had significant success. However, recently virus variants have emerged that can evade the immunity in a host achieved through vaccination. Consequently, new therapeutic agents that can efficiently prevent infection from these new variants, and hence COVID-19 spread are urgently required. To achieve this, extensive characterization of virus-host cell interactions to identify effective therapeutic targets is warranted. Here, we report a cell surface entry pathway of SARS-CoV-2 that exists in a cell type-dependent manner is TMPRSS2-independent but sensitive to various broad-spectrum metalloproteinase inhibitors such as marimastat and prinomastat. Experiments with selective metalloproteinase inhibitors and gene-specific siRNAs revealed that a disintegrin and metalloproteinase 10 (ADAM10) is partially involved in the metalloproteinase pathway. Consistent with our finding that the pathway is unique to SARS-CoV-2 among highly pathogenic human coronaviruses, both the furin cleavage motif in the S1/S2 boundary and the S2 domain of SARS-CoV-2 spike protein are essential for metalloproteinase-dependent entry. In contrast, the two elements of SARS-CoV-2 independently contributed to TMPRSS2-dependent S2 priming. The metalloproteinase pathway is involved in SARS-CoV-2-induced syncytia formation and cytopathicity, leading us to theorize that it is also involved in the rapid spread of SARS-CoV-2 and the pathogenesis of COVID-19. Thus, targeting the metalloproteinase pathway in addition to the TMPRSS2 and endosome pathways could be an effective strategy by which to cure COVID-19 in the future.

First-in-Man Evaluation of a Sirolimus-Eluting Stent With Abluminal Fluoropolymeric/Triflusal Coating With Ultrathin Struts by OCT at 9 Months' Follow-Up: The PROMETHEUS Study.

OBJECTIVES: We sought to investigate stent healing and neointimal hyperplasia with ihtDEStiny drug-eluting stent (DES) by optical coherence tomography (OCT) examination conducted 9 months after implantation. BACKGROUND: The currently used DES present certain features that have been linked separately to their better performance in terms of efficacy and safety. METHODS: First-in-man, prospective and multicenter study including patients treated with ihtDEStiny stent undergoing OCT examination at 9 months follow up. The ihtDEStiny stent is a sirolimus eluting stent with an oval shape ultrathin struts (68 µm) and an abluminal coating of a fluoropolymer containing the antiplatelet agent triflusal. Primary endpoint was the percentage of obstruction of the in-stent volume by the neointima. RESULTS: In 58 patients (63 lesions) in-stent late lumen loss was 0.11 ± 0.23 mm (95% CI 0.05-0.16) with only in 6% of stents being > 0.5 mm and in-segment binary stenosis was 1.6%. In OCT mean neointima volume obstruction was 10.5 ± 6.9% with a mean neointima thickness of 110.9 ± 89.8 µm. The proportion of uncovered struts was 2.5%, malapposed struts 1.1% and malapposed/uncovered struts 0.7% and no subclinical thrombi detected. Mean incomplete stent apposition area was 0.1 ± 0.1 mm2. At 12 months target lesion revascularization rate was 3% and no stent thrombosis was reported. CONCLUSIONS: In this study the ihtDEStiny stent has shown a very low degree of neointimal proliferation associated with a low rate of uncovered/malapposed struts and total absence of subclinical thrombi at 9 months follow up.

Consistent and High-Frequency Identification of an Intra-Sample Genetic Variant of SARS-CoV-2 with Elevated Fusogenic Properties (preprint)

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a genome comprised of a ~30K nucleotides non-segmented, positive single-stranded RNA. Although its RNA-dependent RNA polymerase exhibits exonuclease proofreading activity, viral sequence diversity can be induced by replication errors and host factors. These variations can be observed in the population of viral sequences isolated from infected host cells and are not necessarily reflected in the genome of transmitted founder viruses. We profiled intra-sample genetic diversity of SARS-CoV-2 variants using 15,289 high-throughput sequencing datasets from infected individuals and infected cell lines. Most of the genetic variations observed, including C->U and G->U, were consistent with errors due to heat-induced DNA damage during sample processing, and/or sequencing protocols. Despite high mutational background, we confidently identified intra-variable positions recurrent in the samples analyzed, including several positions at the end of the gene encoding the viral S protein. Notably, most of the samples possesses a C->A missense mutation resulting in the S protein lacking the last 20 amino acids (S{Delta}20). Here we demonstrate that S{Delta}20 exhibits increased cell-to-cell fusion and syncytia formations. Our findings are suggestive of the consistent emergence of high-frequency viral quasispecies that are not horizontally transmitted but involved in intra-host infection and spread. Author summaryThe severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its associated disease, COVID-19, has caused significant worldwide mortality and unprecedented economic burden. Here we studied the intra-host genetic diversity of SARS-CoV-2 genomes and identified a high-frequency and recurrent non-sense mutation yielding a truncated form of the viral spike protein, in both human COVID-19 samples and in cell culture experiments. Through the use of a functional assay, we observed that this truncated spike protein displays an elevated fusogenic potential and forms syncytia. Given the high frequency at which this mutation independently arises across various samples, it can be hypothesized that this deletion mutation provides a selective advantage to viral replication and may also have a role in pathogenesis in humans.