Advances in the relationship between coronavirus infection and coagulation function

Downregulation of the Protein C Signaling System Is Associated with COVID-19 Hypercoagulability-A Single-Cell Transcriptomics Analysis

Because of the interface between coagulation and the immune response, it is expected that COVID-19-associated coagulopathy occurs via activated protein C signaling. The objective was to explore putative changes in the expression of the protein C signaling network in the liver, peripheral blood mononuclear cells, and nasal epithelium of patients with COVID-19. Single-cell RNA-sequencing data from patients with COVID-19 and healthy subjects were obtained from the COVID-19 Cell Atlas database. A functional protein-protein interaction network was constructed for the protein C gene. Patients with COVID-19 showed downregulation of protein C and components of the downstream protein C signaling cascade. The percentage of hepatocytes expressing protein C was lower. Part of the liver cell clusters expressing protein C presented increased expression of ACE2. In PBMC, there was increased ACE2, inflammatory, and pro-coagulation transcripts. In the nasal epithelium, PROC, ACE2, and PROS1 were expressed by the ciliated cell cluster, revealing co-expression of ACE-2 with transcripts encoding proteins belonging to the coagulation and immune system interface. Finally, there was upregulation of coagulation factor 3 transcript in the liver and PBMC. Protein C could play a mechanistic role in the hypercoagulability syndrome affecting patients with severe COVID-19.

Coagulopathy in elderly patients with coronavirus disease 2019

BACKGROUND

Since the outbreak of coronavirus disease 2019 (COVID-19), clinical features have been analyzed in detail. However, coagulopathy in elderly COVID-19 patients has been scarcely reported.

METHODS

Coagulation parameters of 189 patients with COVID-19 in Tongji hospital were retrospectively analyzed among age groups.

RESULTS

Patients were divided into 2 groups: older group (≥65 years, n = 87) and younger group (<65 years, n = 102). The proportion of patients with elevated fibrinogen (79.0% vs 59.6%, p = .005) and D-dimer (78.0% vs 55.2%, p = .001) shows the significant difference between the groups. The elderly patients revealed significantly longer prothrombin time (14.0 [13.4-14.4]s vs 13.6 [13.2-14.1]s, p = .026), higher D-dimer (1.00 [0.5-1.9] μg/mL vs 0.6 [0.3-1.6] μg/mL, p = .013) and fibrinogen (5.2 [4.1-6.2] g/L vs 4.4 [3.4-5.7] g/L, p = .004) levels, compared to the younger group. A positive correlation was observed between the coagulation parameters and inflammatory markers including high-sensitivity C-reactive protein and interleukin-6 (p < .05).

CONCLUSIONS

The hypercoagulable state is more common in elderly COVID-19 patients, and coagulopathy is associated with excessive systemic inflammation.