Aspiration and Inspiration: Using Bronchoalveolar Lavage for Toxicity Assessment

Canine Cerebrospinal Fluid Analysis Using Two New Automated Techniques: The Sysmex XN-V Body Fluid Mode and an Artificial-Intelligence-Based Algorithm

Cerebrospinal fluid analysis is an important diagnostic test when assessing a neurological canine patient. For this analysis, the total nucleated cell count and differential cell counts are routinely taken, but both involve time-consuming manual methods. To investigate faster automated methods, in this study, the Sysmex XN-V body fluid mode and the deep-learning-based algorithm generated by the Olympus VS200 slide scanner were compared with the manual methods in 161 canine cerebrospinal fluid samples for the total nucleated cell count and in 65 samples with pleocytosis for the differential counts. Following incorrect gating by the Sysmex body fluid mode, all samples were reanalyzed with manually set gates. The Sysmex body fluid mode then showed a mean bias of 15.19 cells/μL for the total nucleated cell count and mean biases of 4.95% and -4.95% for the two-part differential cell count, while the deep-learning-based algorithm showed mean biases of -7.25%, -0.03% and 7.27% for the lymphocytes, neutrophils and monocytoid cells, respectively. Based on our findings, we propose that the automated Sysmex body fluid mode be used to measure the total nucleated cell count in canine cerebrospinal fluid samples after making adjustments to the predefined settings from the manufacturer. However, the two-part differential count of the Sysmex body fluid mode and the deep-learning-based algorithm require some optimization.

Comparison of Sysmex XN-V body fluid mode and deep-learning-based quantification with manual techniques for total nucleated cell count and differential count for equine bronchoalveolar lavage samples

BACKGROUND

Bronchoalveolar lavage (BAL) is a diagnostic method for the assessment of the lower respiratory airway health status in horses. Differential cell count and sometimes also total nucleated cell count (TNCC) are routinely measured by time-consuming manual methods, while faster automated methods exist. The aims of this study were to compare: 1) the Sysmex XN-V body fluid (BF) mode with the manual techniques for TNCC and two-part differential into mononuclear and polymorphonuclear cells; 2) the Olympus VS200 slide scanner and software generated deep-learning-based algorithm with manual techniques for four-part differential cell count into alveolar macrophages, lymphocytes, neutrophils, and mast cells. The methods were compared in 69 clinical BAL samples.

RESULTS

Incorrect gating by the Sysmex BF mode was observed on many scattergrams, therefore all samples were reanalyzed with manually set gates. For the TNCC, a proportional and systematic bias with a correlation of r = 0.79 was seen when comparing the Sysmex BF mode with manual methods. For the two-part differential count, a mild constant and proportional bias and a very small mean difference with moderate limits of agreement with a correlation of r = 0.84 and 0.83 were seen when comparing the Sysmex BF mode with manual methods. The Sysmex BF mode classified significantly more samples as abnormal based on the TNCC and the two-part differential compared to the manual method. When comparing the Olympus VS200 deep-learning-based algorithm with manual methods for the four-part differential cell count, a very small bias in the regression analysis and a very small mean difference in the difference plot, as well as a correlation of r = 0.85 to 0.92 were observed for all four cell categories. The Olympus VS200 deep-learning-based algorithm also showed better precision than manual methods for the four-part differential cell count, especially with an increasing number of analyzed cells.

CONCLUSIONS

The Sysmex XN-V BF mode can be used for TNCC and two-part differential count measurements after reanalyzing the samples with manually set gates. The Olympus VS200 deep-learning-based algorithm correlates well with the manual methods, while showing better precision and can be used for a four-part differential cell count.

PGLYRP1-mIgG2a-Fc inhibits macrophage activation via AKT/NF-κB signaling and protects against fatal lung injury during bacterial infection

Severe bacterial pneumonia leads to acute respiratory distress syndrome (ARDS), with a high incidence rate and mortality. It is well-known that continuous and dysregulated macrophage activation is vital for aggravating the progression of pneumonia. Here, we designed and produced an antibody-like molecule, peptidoglycan recognition protein 1-mIgG2a-Fc (PGLYRP1-Fc). PGLYRP1 was fused to the Fc region of mouse IgG2a with high binding to macrophages. We demonstrated that PGLYRP1-Fc ameliorated lung injury and inflammation in ARDS, without affecting bacterial clearance. Besides, PGLYRP1-Fc reduced AKT/nuclear factor kappa-B (NF-κB) activation via the Fc segment bound Fc gamma receptor (FcγR)-dependent mechanism, making macrophage unresponsive, and immediately suppressed proinflammatory response upon bacteria or lipopolysaccharide (LPS) stimulus in turn. These results confirm that PGLYRP1-Fc protects against ARDS by promoting host tolerance with reduced inflammatory response and tissue damage, irrespective of the host's pathogen burden, and provide a promising therapeutic strategy for bacterial infection.

Identification of FDA Approved Drugs with Antiviral Activity against SARS-CoV-2: A Tale from structure-based drug repurposing to host-cell mechanistic investigation

The continuing heavy toll of the COVID-19 pandemic necessitates development of therapeutic options. We adopted structure-based drug repurposing to screen FDA-approved drugs for inhibitory effects against main protease enzyme (Mpro) substrate-binding pocket of SARS-CoV-2 for non-covalent and covalent binding. Top candidates were screened against infectious SARS-CoV-2 in a cell-based viral replication assay. Promising candidates included atovaquone, mebendazole, ouabain, dronedarone, and entacapone, although atovaquone and mebendazole were the only two candidates with IC50s that fall within their therapeutic plasma concentration. Additionally, we performed Mpro assays on the top hits, which demonstrated inhibition of Mpro by dronedarone (IC50 18 µM), mebendazole (IC50 19 µM) and entacapone (IC50 9 µM). Atovaquone showed only modest Mpro inhibition, and thus we explored other potential mechanisms. Although atovaquone is Dihydroorotate dehydrogenase (DHODH) inhibitor, we did not observe inhibition of DHODH at the respective SARS-CoV-2 IC50. Metabolomic profiling of atovaquone treated cells showed dysregulation of purine metabolism pathway metabolite, showing that ecto-5′-nucleotidase (NT5E) is downregulated by atovaquone at concentrations equivalent to its antiviral IC50. Atovaquone and mebendazole are promising candidates targeting SARS-CoV-2, however atovaquone did not significantly inhibit Mpro at therapeutically meaningful concentrations but may inhibit SARS-CoV-2 viral replication by targeting host purine metabolism.

Pulmonary toxicity of tungsten trioxide nanoparticles in an inhalation study and an intratracheal instillation study

Objectives

We conducted inhalation and intratracheal instillation studies in order to examine the effects of tungsten trioxide (WO₃) nanoparticles on the lung, and evaluated whether or not the nanoparticles would cause persistent lung inflammation.

Methods

In the inhalation study, male 10‐week‐old Fischer 334 rats were classified into 3 groups. The control, low‐dose, and high‐dose groups inhaled clean air, 2, and 10 mg/m³ WO₃ nanoparticles, respectively, for 6 h each day for 4 weeks. The rats were dissected at 3 days, 1 month, and 3 months after the inhalation, and the bronchoalveolar lavage fluid (BALF) and lung tissue were examined. In the intratracheal instillation study, male 12‐week‐old Fischer 334 rats were divided into 3 subgroups. The control, low‐dose, and high‐dose groups were intratracheally instilled 0.4 ml distilled water, 0.2, and 1.0 mg WO₃ nanoparticles, respectively, dissolved in 0.4 ml distilled water. The rats were sacrificed at 3 days, 1 week, and 1 month after the intratracheal instillation, and the BALF and lung tissue were analyzed as in the inhalation study.

Results

The inhalation and instillation of WO₃ nanoparticles caused transient increases in the number and rate of neutrophils, cytokine‐induced neutrophil chemoattractant (CINC)‐1, and CINC‐2 in BALF, but no histopathological changes or upregulation of heme oxygenase (HO)‐1 in the lung tissue.

Conclusion

Our results suggest that WO₃ nanoparticles have low toxicity to the lung. According to the results of the inhalation study, we also propose that the no observed adverse effect level (NOAEL) of WO₃ nanoparticles is 2 mg/m³.

Research-Relevant Clinical Pathology Resources: Emphasis on Mice, Rats, Rabbits, Dogs, Minipigs, and Non-Human Primates

Clinical pathology testing for investigative or biomedical research and for preclinical toxicity and safety assessment in laboratory animals is a distinct specialty requiring an understanding of species specific and other influential variables on results and interpretation. This review of clinical pathology principles and testing recommendations in laboratory animal species aims to provide a useful resource for researchers, veterinary specialists, toxicologists, and clinical or anatomic pathologists.

Review of the Technical, Toxicological, and PKPD Considerations for Conducting Inhalation Toxicity Studies on Biologic Pharmaceuticals-The Outcome of a Cross-Industry Working Group Survey

The inhaled route is still a relatively novel route for delivering biologics and poses additional challenges to those encountered with inhaled small molecules, further complicating the design and interpretation of toxicology studies. A working group formed to summarize the current knowledge of inhaled biologics across industry and to analyze data collated from an anonymized cross-industry survey comprising 12 inhaled biologic case studies (18 individual inhalation toxicity studies on monoclonal antibodies, fragment antibodies, domain antibodies, oligonucleotides, and proteins/peptides). The output of this working group provides valuable insights into the issues faced when conducting toxicology studies with inhaled biologics, including common technical considerations on aerosol generation, use of young and sexually mature nonhuman primates, pharmacokinetic/pharmacodynamic modeling, exposure and immunogenicity assessment, maximum dose setting, and no observed adverse effect levels determination. Although the current data set is too small to allow firm conclusions, testing of novel biologics remains an active area and is likely to remain so for molecules where delivery via the inhaled route is beneficial. In the future, it is hoped others will continue to share their experiences and build on the conclusions of this review to further improve our understanding of these complex issues and, ultimately, facilitate the safe introduction of inhaled biologics into clinical use.

Inspiration and Exasperation: The Challenges of Inhaled Biologics

The delivery of biotherapeutic molecules (antibodies, proteins, peptides) and nucleic acids via the respiratory route has presented challenges for regulatory approval, due in part to a lack of understanding of the expected pathology, mechanisms of toxicity, and immunogenicity induced by the inhalation route. Although the first inhaled biotherapeutic was approved some time ago (Dornase Alfa, Pulmozyme; Genetech, 1993), no other inhaled biotherapeutics have been marketed for the treatment of human disease other than the inhaled insulins (Exubera; Pfizer, 2006 and Afrezza; Mannkind Corporation, 2014). As a result, scientific knowledge within the toxicologic pathology community is fragmented with precious little publicly available data. Therefore, one of the aims of this special edition was to generate a collection of manuscripts that pathologists and toxicologists could refer in order to understand the pathology, mechanisms of toxicity, immunogenicity, and challenges associated with the development of inhaled biotherapeutics.