ABSTRACT
Background: Platelets are effectors of hemostasis and play a major role in coordinating immune and inflammatory activities. Suitable animal models are needed to study COVID-19-associated coagulopathy and platelet effector functions in COVID-19, which are currently poorly understood. Aim(s): We aimed to characterize alterations of platelets isolated from K18-hACE2 transgenic mice infected with SARS-CoV-2. Method(s): Heterozygous K18-hACE2 (human ACE2) and C57BL/6J mice were used to study SARS-CoV-2 infectivity. Lung infection, infiltration, and platelet aggregation were characterized with histology and immunohistochemistry. Platelet response to SARS-CoV-2 infection was quantified by mass spectrometry analysis of proteomics and phosphoproteomics. Western blotting, ELISA, and multiplex plasma profiling were performed to validate the proteomics and phosphoproteomics data. Result(s): SARS-CoV-2 inoculated (10E6PFU, i.n.) K18-hACE2 mice started to lose weight at 4 days post-infection (dpi) and showed 90% lethality at 7-dpi in association with viral neuroinvasion. Histopathologic findings of infected K18-hACE2 mice included progressive lymphohistiocytic interstitial pneumonia with absence of diffuse alveolar damage. Lungs of infected K18-hACE2 mice (2-/ 4-dpi) showed mild increase in CD61+ aggregates compared to sham mice, but no overt tissue thrombosis. Gene ontology and pathway analyses of platelet proteomics and phosphoproteomics revealed that SARS-CoV-2 infection significantly upregulates the complement-coagulation cascades (F2/12/13, Tfpi, C1ra, Cd55, C4bp) and platelet activation-adhesion-degranulation proteins (Vwf, Itgb3/5, Selp, Pecam1) and chemokine (Pf4, Cxcl5/12) signaling at 2-dpi. However, interferon (Ddx58, Trim25, Mapk3) signaling was dominant at 4-dpi. Activation of proteomics and phosphoproteomics protein markers were highly correlated with platelet activation and interferon signaling at 2-/ 4-dpi, respectively. Plasma chemokine (e.g., Ccl8 and Pf4) and cytokines (e.g., IL6) were significantly elevated at 2-/ 4-dpi. SARS-CoV-2 spike protein was abundant at 2-/ 4-dpi in the lungs but not in platelets and kidneys, which correlated with no infectious virus in the serum. Conclusion(s): Platelet re-programming towards activation-degranulation-aggregation is likely attributable to a pneumonia-induced elevated circulatory factors (e.g., cytokines)-driven response rather than direct platelet infection.
ABSTRACT
Introduction In the Viterbo province (3612 Km 2 divided into 60 municipalities) is operative a Domiciliary Hematologic Care Unit (DHCU) for clinical assistance to frail patients (pts) with hemopathies: DHCU nursing activity is done by 4 units who were employed during Covid-19 pandemia to avoid as possible risks of viral contagium due to hospital admissions of our pts. Aims To evaluate the entity and type of nursing management for frail pts followed by DHCU during the first year of Covid-19 pandemia. Methods All nursing activities from 3/2020 to 3/2021 in the lockdown framework were analysed. On the whole, 107 pts in 43 municipalities of Viterbo province were followed by DHCU nurses in the study period. Results Main features of the pts at baseline of domiciliary assistance are reported in the Table. At beginning of the study period (08/03/2020), 37 pts (34.5%) were already followed by DHCU, while 70 pts (65.5%) entered domiciliary assistance during the year of study. Median distance from DHCU central site to pts house was 25 Km [Interquartile range (IQR) 16 - 34]: distance from DHCU was < 20 Km in 32 cases (29.9%), ≥ 20 < 40 Km in 57 (53.2%) and ≥ 40 Km in 18 (16.9%). A total number of 2609 nursing accesses was done in the whole period. According to different procedures, 1152 blood samples were performed, with a median number of 7 (IQR 3 - 15) for each pts: in addition, there were 1040 accesses for chemotherapy (CHT) administration (108 cycles of azacytidine in 15 pts, 87 bortezomib-based cycles in 30 pts, 16 administrations of other CHTs in 2 pts) and 417 accesses for other procedures (260 venous catheter medications, 125 therapy other than CHT, 32 nursing assistances of transfusions or marrow aspirates). Finally, 20 pts were vaccinated at home with respective caregivers. During the entire study period, 2 pts (1.8%) developed Covid-19 infection while in home care. At the last follow-up (31/03/2021), 59 pts (55.1%) were alive and still followed by DHCU, 20 pts (18.6%) were alive and returned to sDay-Hospital (DH) setting due to improvement of clinical conditions and 28 pts (26.3%) died while in domiciliary assistance. Conclusions Domiciliary nurse assistance during Covid-19 pandemia allowed to follow in a safer way compared to standard DH/ordinary admission settings > 100 frail pts with hemopathies, most of them in 1 st or subsequent active lines of therapy, in a wide geographic area. In our opinion, this approach should represent the best type of assistance for a high rate of hematologic pts even beyond Covid-19 period of pandemia. [Formula presented] Disclosures: Stagno: Novartis: Consultancy, Honoraria, Other: Support for attending meetings and/or travel, Research Funding;Pfizer: Consultancy, Honoraria, Other: Support for attending meetings and/or travel;InCyte: Consultancy, Honoraria. Latagliata: BMS Cellgene: Honoraria;Pfizer: Honoraria;Novartis: Honoraria.
ABSTRACT
The aim of this study was to investigate the persistence of SARS-CoV-2 in post-mortem swabs of subjects who died from SARS-CoV-2 infection. The presence of the virus was evaluated post-mortem from airways of 27 SARS-CoV-2 positive patients at three different time points (T1 2 h;T2 12 h;T3 24 h) by real-time PCR. Detection of antibodies to SARS-CoV-2 was performed by Maglumi 2019-nCoV IgM/IgG chemiluminescence assay. SARS-CoV-2 viral RNA was still detectable in 70.3% of cases within 2 h after death and in 66,6% of cases up to 24 h after death. Our data showed an increase of the viral load in 78,6% of positive individuals 24 h post-mortem (T3) in comparison to that evaluated 2 h after death (T1). Noteworthy, we detected a positive T3 post-mortem swab (24 h after death) from 4 subjects who were negative at T1 (2 h after death). The results of our study may have an important value in the management of deceased subjects not only with a suspected or confirmed diagnosis of SARS-CoV-2, but also for unspecified causes and in the absence of clinical documentation or medical assistance.