1
|
Pearson J, Wessler T, Chen A, Boucher RC, Freeman R, Lai SK, Pickles R, Forest MG. Modeling identifies variability in SARS-CoV-2 uptake and eclipse phase by infected cells as principal drivers of extreme variability in nasal viral load in the 48 h post infection. J Theor Biol 2023; 565:111470. [PMID: 36965846 PMCID: PMC10033495 DOI: 10.1016/j.jtbi.2023.111470] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 03/25/2023]
Abstract
The SARS-CoV-2 coronavirus continues to evolve with scores of mutations of the spike, membrane, envelope, and nucleocapsid structural proteins that impact pathogenesis. Infection data from nasal swabs, nasal PCR assays, upper respiratory samples, ex vivo cell cultures and nasal epithelial organoids reveal extreme variabilities in SARS-CoV-2 RNA titers within and between the variants. Some variabilities are naturally prone to clinical testing protocols and experimental controls. Here we focus on nasal viral load sensitivity arising from the timing of sample collection relative to onset of infection and from heterogeneity in the kinetics of cellular infection, uptake, replication, and shedding of viral RNA copies. The sources of between-variant variability are likely due to SARS-CoV-2 structural protein mutations, whereas within-variant population variability is likely due to heterogeneity in cellular response to that particular variant. With the physiologically faithful, agent-based mechanistic model of inhaled exposure and infection from (Chen et al., 2022), we perform statistical sensitivity analyses of the progression of nasal viral titers in the first 0-48 h post infection, focusing on three kinetic mechanisms. Model simulations reveal shorter latency times of infected cells (including cellular uptake, viral RNA replication, until the onset of viral RNA shedding) exponentially accelerate nasal viral load. Further, the rate of infectious RNA copies shed per day has a proportional influence on nasal viral load. Finally, there is a very weak, negative correlation of viral load with the probability of infection per virus-cell encounter, the model proxy for spike-receptor binding affinity.
Collapse
Affiliation(s)
- Jason Pearson
- Department of Mathematics, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - Timothy Wessler
- Department of Mathematics, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alex Chen
- Department of Mathematics, California State University-Dominguez Hills, Carson, CA 90747, USA
| | - Richard C Boucher
- Marsico Lung Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ronit Freeman
- Department of Applied Physical Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - Samuel K Lai
- Department of Microbiology and Immunology, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA; UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA and North Carolina State University, Raleigh, NC 27606, USA; Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - Raymond Pickles
- Marsico Lung Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
| | - M Gregory Forest
- Department of Mathematics, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA; Department of Applied Physical Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA; UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA and North Carolina State University, Raleigh, NC 27606, USA.
| |
Collapse
|
2
|
Cheng LH, Wu PC, Shih CP, Wang HW, Chen HC, Lin YY, Chu YH, Lee JC. Nasal septal abscess: a 10-year retrospective study. Eur Arch Otorhinolaryngol 2019; 276:417-20. [PMID: 30506184 DOI: 10.1007/s00405-018-5212-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 11/16/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Nasal septal abscess is an uncommon condition but it can cause potentially life-threatening intracranial complications and cosmetic nasal deformity. METHODS We analyzed ten years of cases to determine the optimal diagnostic and therapeutic modalities. A retrospective review of case notes from Tri-Service General Hospital archives was performed. Records of six patients diagnosed with nasal septal abscess, who were treated from September 2007 to August 2017 were retrospectively reviewed. Patients' clinical symptoms, etiology, diagnostic methods, bacteriology, antibiotic and surgical treatment were recorded and analyzed. RESULTS Out of six patients diagnosed with nasal septal abscess, three were male and three were female. Ages ranged from 19 to 75 years (mean 51 years). The most common symptoms at presentation were nasal pain and nasal obstruction. Typical etiologies were trauma or acute sinusitis, but uncontrolled diabetes mellitus was also an important etiology. In the series of six patients, four of them had positive findings of abscess and in drainage, had the following bacterial cultures: Staphylococcus aureus (two cases), methicillin-resistant S. aureus (one case), and Klebsiella pneumoniae (one case). In addition to antibiotic treatment, all patients underwent surgical drainage and had complete resolution of disease without intracranial complications during at least 1 year of follow-up. However, two out of the six patients developed saddle nose deformity. CONCLUSIONS This study highlights that: 1. In view of the rapidly increasing number of diabetes mellitus cases, uncontrolled diabetes mellitus is an important etiology of nasal septal abscess. 2. Although S. aureus is the most common pathogen, we must pay attention to methicillin-resistant S. aureus (MRSA) to prevent severe complications and patients who are at increased risk for MRSA colonization should be administrated antibiotics against MRSA initially. 3. Nasal septal abscess should be managed with parenteral broad spectrum antibiotics, appropriate drainage and immediate reconstruction of the destructed septal cartilage with autologous cartilage graft, to prevent serious intracranial complications and cosmetic nasal deformity.
Collapse
|