In a latest study published in the journal Science Translational Medicine, researchers characterized long-term pulmonary consequences of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) mouse-adapted strain (MA10) infection in BALB/c laboratory mice.
Study: SARS-CoV-2 infection produces chronic pulmonary epithelial and immune cell dysfunction with fibrosis in mice. Image Credit: eamesBot / Shutterstock
Due to a lack of longitudinal tissue samples, the mechanistic basis of post-acute sequelae of SARS-CoV-2 (PASC)-related lung abnormalities is barely understood. Moreover, little is known about the underlying mechanisms governing non-viral chronic active pneumonia (CAP) or pulmonary fibrosis (PF) in humans, providing incomplete roadmaps for studies of SARS-CoV-2 pulmonary pathogenesis. Here it is also noteworthy that human autopsy samples are heterogeneous and describe disease only at a specific time. Therefore, they do not elucidate the pathogenesis of post-SARS-CoV-2 lung disease.
Mice infected with MA10 suffer from an acute respiratory distress syndrome (ARDS) similar to humans. Therefore, BALB/c mice present an opportunity to investigate PASC pathogenesis from acute to clinical recovery phases. Additionally, this murine model facilitates testing countermeasures to ameliorate PASC. Previous studies have also not described PASC-like disease phenotypes in the lung after virus clearance.
In the present study, researchers inoculated 103 plaque-forming units (PFU) of SARS-CoV-2 MA10 in one-year-old female BALB/c mice to induce severe acute disease. Likewise, they inoculated 10-week-old mice with a higher inoculum of MA10 (104 PFU) to induce similar disease severity.
As per the recommendations for diagnosing different COVID-19 phases in humans, the team necropsied these mice at two, seven, 15, 30, 60, and 120 days post-infection (dpi). They used the retrieved samples for the study analyses.
The team used complementing virological and histological methods to assess lung damage in surviving mice. Further, they utilized digital spatial profiling (DSP) to identify transcriptional profiles during acute and chronic disease phases to characterize tissue damage and repair in mice and humans. The team supplemented these techniques with immunohistochemistry (IHC) and computed tomography (CT) scanning. They also used ribonucleic acid in situ hybridization (RNA-ISH) to validate data obtained from DSP analyses. Lastly, they investigated measures to identify early biomarkers to identify PASC and evaluated countermeasures to prevent lung disease during PASC.
The older mice that survived MA10 infection cleared the infection by 15 dpi. Like humans, they had damaged pulmonary epithelia that turned into persistent pulmonary lesions, and micro-CT also revealed subpleural opacities and fibrosis.
The lesions were heterogeneous and varied in severity between 30 to 120 dpi. Further, these mice had abnormally repairing alveolar epithelial type II (AT2) cells and interstitial macrophages alongside persistent lung lesions. In subpleural regions, they exhibited myofibroblast proliferation, accumulated lymphoid cells, and deposited interstitial collagen.
SARS-CoV-2 MA10 infection causes lung damage in aged surviving mice. 1-year-old female BALB/c mice were infected with 103 PFU SARS-CoV-2 MA10 (n=74) or PBS (n=24) and monitored for (A) percent starting weight and (B) survival. (C) Log transformed infectious virus lung titers were assayed at indicated time points. Dotted line represents LOD. Undetected samples are plotted at half the LOD. (D to F) Lung function was assessed by whole-body plethysmography for (D) PenH, (E) Rpef, and (F) EF50. (G) Histopathological analysis of lungs at indicated time points are shown. H&E indicates hematoxylin and eosin staining. SMA indicates DAB-labeling (brown) immunohistochemistry for α-smooth muscle actin. Picrosirius Red staining (bright pink-red) highlights collagen fibers. Image scale bars represents 1000 μm for low magnification and 100 μm for 400X images. (H) Disease incidence scoring is shown for indicated time points: 0 = 0% of total area of examined section, 1 = less than 5%; 2 = 6 to 10%; 3 = 11 to 50%; 4 = 51 to 95%; 5 = greater than 95%. Graphs represent individuals necropsied at each time point (C and H), with the average value for each treatment and error bars representing standard error of the mean. Mock infected animals represented by open black circles and SARS-CoV-2 MA10 infected animals are represented by closed red circles.
These mice also had elevated levels of several pro-inflammatory and pro-fibrotic cytokines. These included interleukin-1Beta (IL-1β), IL-33, IL-17A, tumor necrosis factor-alpha (TNF-α), granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor growth factor-beta (TGF-β).
Although most cytokines returned to their normal levels by 30 dpi, sub-pleural fibrotic regions exhibited prolonged up-regulation of TGF-β signaling, as observed during DSP and RNA-ISH. Previous studies have observed similar heterogeneous cellular and fibrotic features in subpleural regions of late-stage COVID-19 patients.
The infection in bronchioles, particularly in subpleural regions, provided cues to the etiology of the late-stage alveolar CAP/PF response. Despite similar infections, bronchioles were repaired without any evidence of fibrotic sequelae. In all probability, tissue-specific ISG responses protected bronchioles from this adverse fate.
Furthermore, CD4+ and CD8+ T cell populations increased in SARS-CoV-2-diseased areas of mouse lungs, and peripheral lymphoid aggregations characterized chronic disease. Consistent with human studies, DSP and flow cytometry data confirmed the expansion of the interstitial macrophage population. Most importantly, the study data confirmed that replication-defective and pro-inflammatory transitional cells, including alveolar differentiation intermediate (ADI)/ damage-associated transient progenitor (DATP)/pre-AT1 transitional cell state (PATS) emerges early after SARS-CoV-2 infection and persists with continued inflammation and failure of repair.
The authors first observed these cells at two dpi in the test animals, and they persisted through 30 dpi in diseased but not morphologically intact alveolar regions. Histological studies evidenced the activation of ADI/DATP/PATS cells-related extracellular matrix pathways in the subpleural areas.
Early molnupiravir treatment weakened chronic PASC in the SARS-CoV-2 MA10 mouse model. Similarly, early administration of direct-acting antiviral, Nintedanib also blunted maximal fibrotic responses to SARS-CoV-2 between seven and 15 dpi. However, additional studies could confirm these findings and evaluate other anti-fibrotic drugs for PASC treatments.
Overall, the current study modeled chronic SARS-CoV-2 to help longitudinally study the molecular pathways mediating long-term COVID-19 pulmonary sequelae to evaluate treatments for human PASC. The study findings also provided cues to the role of host genetics in defining PASC outcomes. Regarding countermeasures, the SARS-CoV-2 MA10 model could help rapidly test agents that may counter the pulmonary CAP/PF effects of COVID-19 during longer clinical trials.
In a latest study published in the Vaccines journal, researchers assessed the efficacy of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) doggybone deoxyribonucleic acid (DNA) vaccine.
Various types of vaccines that attack different targets have been developed so far against coronavirus disease 2019 (COVID-19) infections. Among these, nucleic acid vaccines like the doggybone DNA vaccines (dbDNA vaccines ) have the advantage of fast production since these vaccines require only a viral antigen sequence that can be easily modified to elicit detected viral mutations.
In the present study, researchers compared dbDNA vaccines comprising the SARS-CoV-2 spike (spike) protein sequence (dbDNAS) to the plasmid DNA vaccine (nCoV-S).
The team developed a dbDNA and a plasmid DNA vaccine using similar SARS-CoV-2 S protein sequences. The vaccines nCoV-S(JET) and dbDNAS (JET) facilitate direct comparison between the immunogenicity of the DNA versus the plasmid vaccines. The team vaccinated hamsters with either 0.2 or 0.05 mg of the vaccines via jet injection. Immunogenicity was subsequently determined by a SARS-CoV-2 pseudovirion production and pseudovirion assay (PsVNA) performed after the first and second administration of the vaccines.
The protective efficiency of the dbDNAS(JET), nCoV-S(JET), and dbDNAS(ST-JET) vaccines were analyzed via the immunosuppressed SARS-CoV-2 hamster model. The immunized hamsters were immunocompromised by administering cyclophosphamide and exposing the animals to 1000 PFU SARS-CoV-2 via the intranasal route. The team obtained lung tissue samples nine days post-infection (dpi) which were assessed for viral ribonucleic acid (RNA) via real-time reverse transcription-polymerase chain reaction (rtRT-PCR) and infectious viruses with plaque assays.
The team also assessed whether the polyclonal antibody responses elicited by DNA vaccination with either dbDNAS(JET), nCoV-S(JET), and dbDNAS(ST-JET) vaccines displayed cross-neutralizing efficacy. A plaque reduction neutralization test (PRNT) was performed with the serum samples collected in week 5 against the SARS-CoV-2 D614G variant. The team also used variants including Beta, Epsilon, Iota, Delta, and Delta+ to test the neutralizing capacity of serum obtained from hamsters immunized with a high dose of either of the vaccines.
The study results showed that apart from one hamster vaccinated with the 0.05 mg dbDNAS vaccine, all the hamsters displayed neutralizing titers after the second immunization. The highest levels of neutralization were found in the dbDNAS and nCoV-S groups irrespective of the number of vaccine doses administered. The team noted that there was a remarkable increase in the PsVNA titers after vaccination with the second nCoV-S dose as compared to the mock-vaccinated control participants.
Assessment of the vaccinated immunosuppressed hamsters showed significant differences in the weights of all the hamsters vaccinated with the 0.2mg dbDNAS (ST-JET) dose between seven to nine dpi, the 0.2mg dbDNAS (JET) dose between eight and nine dpi, or 0.2mg nCoV-S (JET) dose at nine dpi. Furthermore, the geometric mean values of the infectious viruses and the viral RNA copies derived from the lung samples were lesser than those in the negative DNA control samples. Overall, this showed that the 0.2 mg dose of either the dbDNAS(ST-JET) or nCoV-S(JET) vaccines had a protective effect on hamsters exposed to SARS-CoV-2. This led to a reduction in weight, viral RNA, as well as infectious viruses found in the lung samples. Moreover, the protective effect was significantly lesser in the hamster vaccinated with 0.5mg of either the dbDNAS(ST-JET), nCoV-S(JET), or the dbDNAS (JET) vaccines.
The team also noted that the serological samples obtained from nCoV-S(JET)-vaccinated hamsters displayed the highest neutralizing titers against the D614G variant. Furthermore, there were no significant differences between the vaccine efficacies against different variants. Notably, all the three vaccines tested in this study induced cross-neutralizing antibodies against all the SARS-CoV-2 variants assessed. The response observed in the hamster vaccinated with the dbDNAS (JET) vaccine was substantially lower than that for the other two vaccines, with one hamster having anti-Iota antibodies and two having anti-Beta antibodies.
Furthermore, the nCoV-S (JET) samples demonstrated the neutralization of Delta and Delta+ variants in a statistically different manner as compared to that of the Beta variant. The variations noted between the neutralization potential against Iota and Delta variants were also remarkable within the cohort vaccinated with nCoV-S (JET).
Overall, the study findings showed that the doggybone DNA COVID-19 vaccine could effectively neutralize SARS-CoV-2 variants of interest. Moreover, the serological samples of the animals vaccinated with novel DNA vaccines displayed effective levels of antibody neutralization against the different SARS-CoV-2 variants.
A shapeshifting robotic microswarm may one day act as a toothbrush, rinse, and dental floss in one. The technology, developed by a multidisciplinary team at the University of Pennsylvania, is poised to offer a new and automated way to perform the mundane but critical daily tasks of brushing and flossing. It's a system that could be particularly valuable for those who lack the manual dexterity to clean their teeth effectively themselves.
The building blocks of these microrobots are iron oxide nanoparticles that have both catalytic and magnetic activity. Using a magnetic field, researchers could direct their motion and configuration to form either bristle-like structures that sweep away dental plaque from the broad surfaces of teeth, or elongated strings that can slip between teeth like a length of floss. In both instances, a catalytic reaction drives the nanoparticles to produce antimicrobials that kill harmful oral bacteria on site.
Experiments using this system on mock and real human teeth showed that the robotic assemblies can conform to a variety of shapes to nearly eliminate the sticky biofilms that lead to cavities and gum disease. The Penn team shared their findings establishing a proof-of-concept for the robotic system in the journal ACS Nano.
"Routine oral care is cumbersome and can pose challenges for many people, especially those who have hard time cleaning their teeth" says Hyun (Michel) Koo, a professor in the Department of Orthodontics and divisions of Community Oral Health and Pediatric Dentistry in Penn's School of Dental Medicine and co-corresponding author on the study. "You have to brush your teeth, then floss your teeth, then rinse your mouth; it's a manual, multi-step process. The big innovation here is that the robotics system can do all three in a single, hands-free, automated way."
"Nanoparticles can be shaped and controlled with magnetic fields in surprising ways," says Edward Steager, a senior research investigator in Penn's School of Engineering and Applied Science and co-corresponding author. "We form bristles that can extend, sweep, and even transfer back and forth across a space, much like flossing. The way it works is similar to how a robotic arm might reach out and clean a surface. The system can be programmed to do the nanoparticle assembly and motion control automatically."
Disrupting oral care technology
"The design of the toothbrush has remained relatively unchanged for millennia," says Koo.
While adding electric motors elevated the basic 'bristle-on-a-stick format', the fundamental concept has remained the same. "It's a technology that has not been disrupted in decades."
Several years ago, Penn researchers within the Center for Innovation & Precision Dentistry (CiPD), of which Koo is a co-director, took steps toward a major disruption, using this microrobotics system.
Their innovation arose from a bit of serendipity. Research groups in both Penn Dental Medicine and Penn Engineering were interested in iron oxide nanoparticles but for very different reasons. Koo's group was intrigued by the catalytic activity of the nanoparticles. They can activate hydrogen peroxide to release free radicals that can kill tooth-decay-causing bacteria and degrade dental plaque biofilms. Meanwhile Steager and engineering colleagues, including Dean Vijay Kumar and Professor Kathleen Stebe, co-director of CiPD, were exploring these nanoparticles as building blocks of magnetically controlled microrobots.
With support from Penn Health Tech and the National Institutes of Health's National Institute of Dental and Craniofacial Research, the Penn collaborators married the two applications in the current work, constructing a platform to electromagnetically control the microrobots, enabling them to adopt different configurations and release antimicrobials on site to effectively treat and clean teeth.
"It doesn't matter if you have straight teeth or misaligned teeth, it will adapt to different surfaces," says Koo. "The system can adjust to all the nooks and crannies in the oral cavity."
The researchers optimized the motions of the microrobots on a small slab of tooth-like material. Next, they tested the microrobots' performance adjusting to the complex topography of the tooth surface, interdental surfaces, and the gumline, using 3D-printed tooth models based on scans of human teeth from the dental clinic. Finally, they trialed the microrobots on real human teeth that were mounted in such a way as to mimic the position of teeth in the oral cavity.
On these various surfaces, the researchers found that the microrobotics system could effectively eliminate biofilms, clearing them of all detectable pathogens. The iron oxide nanoparticles have been FDA approved for other uses, and tests of the bristle formations on an animal model showed that they did not harm the gum tissue.
Indeed, the system is fully programmable; the team's roboticists and engineers used variations in the magnetic field to precisely tune the motions of the microrobots as well as control bristle stiffness and length. The researchers found that the tips of the bristles could be made firm enough to remove biofilms but soft enough to avoid damage to the gums.
The customizable nature of the system, the researchers say, could make it gentle enough for clinical use, but also personalized, able to adapt to the unique topographies of a patient's oral cavity.
To advance this technology to the clinic, the Penn team is continuing to optimize the robots' motions and considering different means of delivering the microrobots through mouth-fitting devices.
They're eager to see their device help patients.
"We have this technology that's as or more effective as brushing and flossing your teeth but doesn't require manual dexterity," says Koo. "We'd love to see this helping the geriatric population and people with disabilities. We believe it will disrupt current modalities and majorly advance oral health care."
Hyun (Michel) Koo is a professor in the Department of Orthodontics and divisions of Community Oral Health and Pediatric Dentistry in the School of Dental Medicine and co-director of the Center for Innovation & Precision Dentistry at the University of Pennsylvania.
Edward Steager is a senior research investigator in Penn's School of Engineering and Applied Science.
Koo and Steager's coauthors on the paper are Penn Dental Medicine's Min Jun Oh, Alaa Babeer, Yuan Liu, and Zhi Ren and Penn Engineering's Jingyu Wu, David A. Issadore, Kathleen J. Stebe, and Daeyeon Lee.
This work was supported in part by the National Institute for Dental and Craniofacial Research (grants DE025848 and DE029985), Procter & Gamble, and the Postdoctoral Research Program of Sungkyunkwan University.
Shares of Valneva VALN have dropped 59.7% in the past three months substantially underperforming the industry’s 23.2% decline.
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Currently, the only marketable product in Valneva’s portfolio is VLA2001, its inactivated COVID-19 vaccine, which is authorized for use in Bahrain, the United Arab Emirates and the United Kingdom.
Though VLA2001 is yet to receive marketing approval from the European Union (“EU”), a marketing authorization application (“MAA”) for VLA2001 is currently under review with the European Medicines Agency (“EMA”). VALN also secured an advance purchase agreement (“APA”) from the European Commission (“EC”) last year in November for the supply of VLA2001 doses to the EU member states once the vaccine is granted marketing authorization.
One of the terms of this APA provides the EC with the right to terminate the agreement if VLA2001 does not receive marketing authorization in the EU by Apr 30, 2022. Last month, the EC decided to exercise this right and communicated its intent to terminate the APA.
Following the receipt of the above notice of intent, Valneva had 30 days from May 13, 2022 to either secure the marketing authorization for VLA2001 from the EMA or propose an acceptable remediation plan. Although the EMA is yet to make a decision on the MAA for VLA2001, the Committee for Medicinal Products for Human Use is expected to take a final vote next week.
Last week, Valneva proposed a remediation plan, which is yet to be accepted by the EU and its member states. However, VALN stated that preliminary, unofficial volume indications received from the EC would not be sufficient to ensure the sustainability of its COVID-19 vaccine program, even though some of the EU member states have confirmed their interest in securing VLA2001 doses.
Hence, Valneva will not be able to enter into an amendment to the APA, which could allow a reduced order. This is likely to lead to the termination of the APA with the EC. Earlier this week, the company also announced that it reached a settlement with the U.K. government concerning the termination of a supply agreement for VLA2001.
The MAA filing in the EU is based on the positive top-line data from the pivotal phase III Cov-Compare study, which Valneva announced last October. The Cov-Compare study compared VLA2001 to AstraZeneca’s AZN COVID vaccine, AZD1222. Data from this study demonstrated the superiority of VLA2001 over the AstraZeneca vaccine.
The study achieved both co-primary endpoints two weeks after the second dose of vaccination. VLA2001 produced superior neutralizing antibody titer levels to AstraZeneca’s AZD1222. Further, VLA2001 demonstrated the same effectiveness as AZN’s AZD1222 in neutralizing antibody seroconversion rates more than 95%.
Valneva is also evaluating VLA2001 as a homologous and heterologous booster. Last month, it initiated a clinical study evaluating a heterologous booster dose of VLA2001 in patients who completed their primary vaccination regimen with an mRNA-based vaccine or natural COVID-19 infection.
Apart from VLA2001, Valneva is evaluating other vaccines in its pipeline for Lyme disease and chikungunya.
VLA15, Valneva’s vaccine candidate for Lyme disease, is being prepared in collaboration with Pfizer PFE. Valneva and PFE completed phase II studies, evaluating VLA15 in both adults (aged 18 years and above) and pediatric participants (from five years to 17 years). Based on data from these phase II studies announced by VALN earlier this April, both Pfizer and Valneva plan to proceed with a phase III study of the vaccine in both pediatric and adult participants, which is expected to start in the third quarter of 2022.
Valneva entered into collaboration with Pfizer in 2020 to develop and commercialize VLA15.
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Valneva currently carries a Zacks Rank #3 (Hold). A better-ranked stock in the overall healthcare sector is Alkermes ALKS, which sports a Zacks Rank #1 (Strong Buy). You can see the complete list of today’s Zacks #1 Rank stocks here.
The Zacks Consensus Estimate for Alkermes’ 2022 loss per share has narrowed from 13 cents to 3 cents in the past 60 days. Shares of Alkermes have risen 3.4% year to date.
Earnings of ALKS beat estimates in each of the last four quarters, the average being 350.5%. In the last reported quarter, Alkermes delivered an earnings surprise of 1,100%.
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