Nomogram for prediction of fatal outcome in patients with severe COVID-19: a multicenter study.

BACKGROUND: To develop an effective model of predicting fatal outcomes in the severe coronavirus disease 2019 (COVID-19) patients. METHODS: Between February 20, 2020 and April 4, 2020, consecutive confirmed 2541 COVID-19 patients from three designated hospitals were enrolled in this study. All patients received chest computed tomography (CT) and serological examinations at admission. Laboratory tests included routine blood tests, liver function, renal function, coagulation profile, C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), and arterial blood gas. The SaO2 was measured using pulse oxygen saturation in room air at resting status. Independent high-risk factors associated with death were analyzed using Cox proportional hazard model. A prognostic nomogram was constructed to predict the survival of severe COVID-19 patients. RESULTS: There were 124 severe patients in the training cohort, and there were 71 and 76 severe patients in the two independent validation cohorts, respectively. Multivariate Cox analysis indicated that age ≥ 70 years (HR = 1.184, 95% CI 1.061-1.321), panting (breathing rate ≥ 30/min) (HR = 3.300, 95% CI 2.509-6.286), lymphocyte count < 1.0 × 109/L (HR = 2.283, 95% CI 1.779-3.267), and interleukin-6 (IL-6) >  10 pg/ml (HR = 3.029, 95% CI 1.567-7.116) were independent high-risk factors associated with fatal outcome. We developed the nomogram for identifying survival of severe COVID-19 patients in the training cohort (AUC = 0.900, 95% CI 0.841-0.960, sensitivity 95.5%, specificity 77.5%); in validation cohort 1 (AUC = 0.811, 95% CI 0.763-0.961, sensitivity 77.3%, specificity 73.5%); in validation cohort 2 (AUC = 0.862, 95% CI 0.698-0.924, sensitivity 92.9%, specificity 64.5%). The calibration curve for probability of death indicated a good consistence between prediction by the nomogram and the actual observation. The prognosis of severe COVID-19 patients with high levels of IL-6 receiving tocilizumab were better than that of those patients without tocilizumab both in the training and validation cohorts, but without difference (P = 0.105 for training cohort, P = 0.133 for validation cohort 1, and P = 0.210 for validation cohort 2). CONCLUSIONS: This nomogram could help clinicians to identify severe patients who have high risk of death, and to develop more appropriate treatment strategies to reduce the mortality of severe patients. Tocilizumab may improve the prognosis of severe COVID-19 patients with high levels of IL-6.

Aptamer-anchored di-polymer shell-capped mesoporous carbon as a drug carrier for bi-trigger targeted drug delivery.

Mesoporous carbon nanomaterials have found applications in drug delivery and cancer therapy. However, it is still quite challenging to fabricate their multifunctional counterparts with high selectivity and efficiency for cancer theranostics. In this study, an alternative and multifunctional nanoplatform was developed, wherein mesoporous carbon nanoparticles (MCNs) were first encapsulated with a polyacrylic acid (PAA) shell, and after doxorubicin (DOX) loading, a polyethyleneimine (PEI) layer was coated to prevent the leakage of DOX. The MUC1 aptamer (Apt) was subsequently anchored onto the surface to provide the ability for specific recognition of cancer cells. This nanocarrier has been shortly termed as Apt@DP-DOX-MCN. The double polymer shells endowed the drug carrier platform with glutathione (GSH) and pH dual stimuli-responsive capability, and controllable release of the encapsulated drug molecule could be realized from the mesoporous and hollow structure, providing a 60% release of the loaded drug. Considering that most tumor sites exhibit more acidic environments or high redox potential, the pH- and GSH-sensitive release capability is particularly useful for controlled drug delivery in cancer therapy as it takes advantage of the inherent characteristics of tumor cells. The anchored MUC1 aptamer facilitates spatiotemporal therapy to improve selectivity towards the objective lesion site and decrease the off-target toxicity. Moreover, the targeted recognition and therapy of human lung adenocarcinoma cancer cells (A549) and breast cancer cells (MCF-7) was successfully achieved.

Glutathione-mediated mesoporous carbon as a drug delivery nanocarrier with carbon dots as a cap and fluorescent tracer.

This work describes a novel and general redox-responsive controlled drug delivery-release nanocarrier with mesoporous carbon nanoparticles (MCNs) gated by customized fluorescent carbon dots (CDs). The modification of MCNs with a disulfide unit enables the system to be sensitive to intracellular glutathione (GSH). The CDs anchoring onto the surface of the MCNs via an electrostatic interaction block the mesopores and thus prevent the leakage of doxorubicin (DOX) loaded inside the channel of the MCNs. Upon the addition of GSH at the physiological environment, the integrity of the system is disrupted due to the dissociation of the disulfide bond; meanwhile stripping the CDs opens the gate and thus triggers the rapid release of the encapsulated DOX. The fluorescence of the CDs is quenched/'turned off' when linking to the MCNs, while it is restored/'turned on' when detaching the CDs from the surface of the MCNs. Thus the fluorescent CDs serve as both a controllable drug release gatekeeper and a fluorescent probe for the visualization of the drug delivery process. By combining these inherent capabilities, the present drug delivery system may be a promising route for designing custom-made visual controlled-release nanodevices specifically governed by in situ stimulus in the cells.

Mesoporous carbon nanoparticles capped with polyacrylic acid as drug carrier for bi-trigger continuous drug release.

A pH and redox responsive bi-trigger continuous drug release nanocarrier is developed by capping mesoporous carbon nanoparticles (MCNs) with polyacrylic acid (PAA), termed as PAA-ss-MCN. The nanocarrier contains disulfide bond units and exhibits pH responsive behavior. It provides promising potential for drug loading due to the internal uniform channels and large surface area of MCNs. PAA grafted on the exterior surface of MCNs acts as a gating layer, generating a novel nano-container and a pH-responsive intelligent nanovalve. By loading doxorubicin (DOX) in PAA-ss-MCN, its sequential release is achieved via two approaches: (1) the intracellular acidic environment induces partial release from the surface of the PAA gating layer, (2) release of the drug sealed in nanochannels via disruption of the integrity of the nanocarrier by glutathione (GSH) caused dissociation of disulfide bonds in the physiological environment. As a result, release of 62% loaded drug is readily achieved. After culturing with HeLa cells, DOX transports into the cell interior and therein exhibits pH- and GSH-sensitive release. As most tumor sites exhibit more acidic environments or high redox potential, the pH- and GSH-sensitive releasing capability of PAA-ss-MCN is particularly useful for controllable drug delivery by taking advantage of the inherent characteristics of tumor cells.