Histopathological pulmonary lesions in rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) macaques experimentally infected with wild-type severe acute respiratory syndrome coronavirus 2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a viral pneumonia characterized by acute interstitial pneumonia and diffuse alveolar damage in humans. Non-human primates (NHPs) are widely used as preclinical animal models for vaccine development against SARS-CoV-2. However, the pathological changes in NHPs have been described only in selected facets and inconsistent nomenclature is used, making it difficult to interpret and compare the outcomes between studies. Here, we present a standardized methodology for histopathological evaluation of experimental infection outcomes in rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) macaques. Evaluation criteria for vascular and epithelial changes in the early (3 days post infection [dpi]) and late (21 dpi) phases of the infection were developed, and a four-grade classification encompassing all the histopathological lung lesions was established. The grades of histopathological lung lesions were higher at 3 dpi compared with 21 dpi in both species of macaques, and there were no statistically significant differences in the grades between the two species at 3 dpi and 21 dpi. This study contextualized the pathological SARS-CoV-2 presentation and standardized the terminology and grading scale for lesion severity to facilitate histopathological examination in the macaque model. By referring to the standardized histopathological criteria and grades proposed here, comparable results with high reproducibility can be obtained in future studies of pathogenicity.

Septic pulmonary embolism: Is it an underestimated diagnosis?

Background

Non-thrombotic pulmonary embolism, an uncommon entity, is defined as the embolization of tissues, microorganisms, air, or foreign material. One subset in this non-thrombotic category is septic pulmonary embolism (SPE) that refers to embolism of microorganisms with or without a thrombotic mantle into the pulmonary vasculature. This condition is often recognized on the basis of imaging with a clinical correlation. Unfortunately, data regarding the pathological features are meager. This has prompted to review such cases at autopsy.

Aims

To study the pathological features of SPE at autopsy.

Materials and Methods

Ten-year (2012 to 2021) autopsy records of the hospital were retrospectively reviewed. The diagnosis was based on the identification of acute necrotizing pulmonary arteritis with peri-bronchoarterial consolidation. These cases were analyzed with reference to the demographics, clinical characteristics, and pulmonary/extrapulmonary findings at autopsy.

Statistical Analysis

Nil.

Results

According to the inclusion criterion, 19 cases demonstrated the presence of SPE. There were 11 men and 8 women with a mean age of 32.1 years. The major source of infection included infection arising from skin and musculo-skeletal system (11 patients, 59.7%). The common clinical presentation included fever, dyspnea, chest pain, hemoptysis, and altered sensorium. The cause of death was mainly due to septicemia and/or confluent lung consolidations. A large number of bacterial colonies were seen in all; Candida species were also identified in two cases. Other lung findings included diffuse alveolar damage, fresh arterial thrombosis, infarction, arterial pseudo-aneurysms, abscess formation, and pyogenic pleuritis.

Conclusion

Presence of an extrapulmonary infection with persistent fever, bacteremia, and pulmonary complaints should raise suspicion for this entity, particularly in resource-poor settings, to prevent grave pulmonary complications.

Characterizing the distribution of alterations in mesothelioma and their correlation to morphology

OBJECTIVES

Mesothelioma is a lethal disease that arises from the serosal lining of organ cavities. Several recurrent alterations have been observed in pleural and peritoneal -mesotheliomas, including in BAP1, NF2, and CDKN2A. Although specific histopathologic parameters have been correlated with prognosis, it is not as well known whether genetic alterations correlate with histologic findings.

METHODS

We reviewed 131 mesotheliomas that had undergone next-generation sequencing (NGS) at our institutions after pathologic diagnosis. There were 109 epithelioid mesotheliomas, 18 biphasic mesotheliomas, and 4 sarcomatoid mesotheliomas. All our biphasic and sarcomatoid cases arose in the pleura. Of the epithelioid mesotheliomas, 73 were from the pleura and 36 were from the peritoneum. On average, patients were 66 years of age (range, 26-90 years) and predominantly male (92 men, 39 women).

RESULTS

The most common alterations identified were in BAP1, CDKN2A, NF2, and TP53. Twelve mesotheliomas did not show a pathogenic alteration on NGS. For epithelioid mesotheliomas in the pleura, the presence of an alteration in BAP1 correlated with low nuclear grade (P = .04), but no correlation was found in the peritoneum (P = .62). Similarly, there was no correlation between the amount of solid architecture in epithelioid mesotheliomas and any alterations in the pleura (P = .55) or peritoneum (P = .13). For biphasic mesotheliomas, cases with either no alteration detected or with an alteration in BAP1 were more likely to be epithelioid predominant (>50% of the tumor, P = .0001), and biphasic mesotheliomas with other alterations detected and no alteration in BAP1 were more likely to be sarcomatoid predominant (>50% of the tumor, P = .0001).

CONCLUSIONS

This study demonstrates a significant association between morphologic features associated with a better prognosis and an alteration in BAP1.

Synovitis, acne, pustulosis, hyperostosis, osteitis syndrome with invisible organizing pneumonia: A case report

We report the case of a 59-year-old female patient, presenting with pustular rash on both hands and pain in the lumbosacral part and left lower limb. A magnetic resonance imaging examination of the left leg was undertaken and the result showed that a malignant lesion with bone destruction of the left femoral shaft could not be excluded. Subsequently, bone tumor was excluded by pathological examination. Lung computed tomography scan showed patchy consolidation and cord shadow in the middle left lung. Subsequently, lung cancer was excluded by pathological examination, and the histopathological changes of lung were consistent with those of organized pneumonia. Blood tests revealed elevated C-reactive protein and erythrocyte sedimentation rate. Antinuclear antibody, rheumatoid factor, and human leukocyte antigen-B27 were unremarkable. Whole body bone scintigraphy via technetium 99m-methyl diphosphonate showed increased radionuclide uptake in the left middle femur. Based on her clinical manifestations, imaging results and bone scintigraphy, the patient was diagnosed as having synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome. Loxoprofen and Tripterygium wilfordii Hook F led to impressive clinical and radiologic improvement.

Could cytology supplant frozen section for intraoperative evaluation of thoracic lesions? A single institutional experience in a developing country

BACKGROUND

The diagnostic performance of cytology was compared with the frozen results and its usability was evaluated as a rapid diagnosis method in intraoperative thoracic surgery in a single institution (Istanbul, Turkey).

METHODS

All 197 subsequent patient specimens (cases) from 158 patients who were sent to our department from the thoracic surgery clinic for an intraoperative diagnosis request between the years 2016 and 2021 were evaluated. Obtained results from frozen and cytology were compared with final paraffin section diagnoses. Lesions were grouped into three different groups as nonneoplastic, benign, and malignant neoplasms.

RESULTS

Diagnostic accuracy values of cytology and frozen sections in intraoperative consultation were 98.8% and 99.4%, respectively. Sensitivity values of cytology and frozen sections in intraoperative consultation were 96.3% and 98.7%, respectively. Specificity values of cytology and frozen sections in intraoperative consultation were 100% and 100%, respectively. Negative predictive values of cytology and frozen sections in intraoperative consultation were 96.7% and 98.9%, respectively. Positive predictive values of cytology and frozen sections in intraoperative consultation were 100% and 100%, respectively. Kappa statistics between cytology and frozen revealed a very high interrater reliability (Cohen's Kappa value: 0.911; p = .001; p < .01). The difficulty in distinguishing primary and metastatic carcinoma, which is mostly undecided in frozen sections and the definitive diagnosis is left to paraffin sections, seems also be a problem in the cytological examination.

CONCLUSIONS

Cytological diagnosis can be used in the evaluation of small biopsy specimens that require tissue preservation in intraoperative consultation, especially for immunohistochemical and advanced genetic studies.

Pediatric Hypersensitivity Pneumonitis: Clinicopathologic Characteristics of Two Cases with Fungal Triggers

Background Hypersensitivity pneumonitis (HP) infrequently presents in childhood. Asthma or a pneumonia-like clinical presentation may lead to diagnostic delay, especially in children. Case Report: We present two cases of HP, a 6-year-old (Case 1) male and a 5-year-old (Case 2) female. Both cases had a negative infectious work-up and patchy ground glass lung opacities on chest computed tomography. Lung biopsies demonstrated lymphocytic bronchiolitis with granulomatous interstitial and peribronchial inflammation. Serology demonstrated elevated immunoglobulin precipitins toward Thermoactinomyces and Aspergillus species in Case 1 and Aspergillus fumigatus in Case 2. Both patients received steroid therapy and had symptom resolution. Conclusions: A diagnosis of HP should be considered in pediatric lung biopsies with granulomatous interstitial and peribronchial inflammation, if infectious etiologies are excluded. Integration of clinical, radiological, and laboratory findings can facilitate a timely diagnosis.

Coronavirus disease 2019 morbid pulmonary pathology: What did we learn from autopsy examinations?

BACKGROUND

Despite the rapidly expanding data on clinical, epidemiological and radiological aspects of coronavirus disease 2019 (COVID-19), little is known about the disease's pathological aspects. The scarcity of pathological data on COVID-19 can be explained by the limited autopsy procedures performed on deceased patients.

AIM

This work aims to review and summarize the pulmonary pathological findings observed in COIVD-19 deceased individuals based on recent case series reports published in English up to September 2020.

METHODS

A search in Google Scholar, PubMed^Ò, MEDLINE^Ò, and Scopus was performed using the keywords "autopsy and COVID-19," "postmortem and COVID-19," and "pulmonary/lung pathology and COVID-19."

RESULTS

Pulmonary autopsy hallmark findings of COVID-19 cases demonstrate the presence of diffuse alveolar damage. The presence of pulmonary thrombi was reported in the majority of patients. Cellular alterations included type 2 pneumocyte hyperplasia, inflammatory cell infiltrates predominantly by lymphocytes, other mononuclear cells, and neutrophils as evident by their specific immunohistochemical markers. Electron microscopy confirmed the presence of virus particles in different cell types, including types 1 and 2 pneumocytes.

CONCLUSION

The few emerging autopsy reports have substantially contributed towards our understanding of COVID-19 pulmonary histopathological aspects. COVID-19 caused acute severe respiratory manifestations that are the leading cause of morbidity and mortality in infected patients. More studies and research are needed to understand the inflammatory processes and histopathological changes associated with COVID-19 in African populations.

RELEVANCE FOR PATIENTS

Postmortem investigations advance important mechanistic knowledge on COVID-19 pathophysiology and clinical outcomes and could facilitate provisions for targeted therapies.

Frequency and Significance of Pathologic Pulmonary Findings in Postmortem Examinations-A Single Center Experience before COVID-19

Coronavirus disease 2019 (COVID-19) has shown the importance of postmortem investigation of deceased patients. For a correct interpretation of the pulmonary findings in this new era, it is, however, crucial to be familiar with pathologic pulmonary conditions observed in postmortem investigations in general. Adequate postmortem histopathological evaluation of the lungs may be affected by suboptimal gross work up, autolysis or poor fixation. Using a standardized preparation approach which consisted in instillation of 4% buffered formaldehyde through the large bronchi for proper fixation and preparing large frontal tissue sections of 1-2 cm thickness after at least 24 h fixation, we comprehensively analyzed postmortem pulmonary findings from consecutive adult autopsies of a two-year period before the occurrence of COVID-19 (2016-2017). In total, significant pathological findings were observed in 97/189 patients (51%), with 28 patients showing more than one pathologic condition. Acute pneumonia was diagnosed 33/128 times (26%), embolism 24 times (19%), primary pulmonary neoplasms 18 times (14%), organizing pneumonia and other fibrosing conditions 14 times (11%), pulmonary metastases 13 times (10%), diffuse alveolar damage 12 times (9%), severe emphysema 9 times (7%) and other pathologies, e.g., amyloidosis 5/128 times (4%). Pulmonary/cardiopulmonary disease was the cause of death in 60 patients (32%). Clinical and pathological diagnoses regarding lung findings correlated completely in 75 patients (40%). Autopsy led to confirmation of a clinically suspected pulmonary diagnosis in 57 patients (39%) and clarification of an unclear clinical lung finding in 16 patients (8%). Major discrepant findings regarding the lungs (N = 31; 16%) comprised cases with clinical suspicions that could not be confirmed or new findings not diagnosed intra vitam. A significant proportion of acute pneumonias (N = 8; 24% of all cases with this diagnosis; p = 0.011) was not diagnosed clinically. We confirmed the frequent occurrence of pulmonary pathologies in autopsies, including inflammatory and neoplastic lesions as the most frequent pathological findings. Acute pneumonia was an important cause for discrepancy between clinical and postmortem diagnostics.

Multiple sclerosing pneumocytomas: a review

Sclerosing pneumocytoma (SP) is a rare benign low-grade tumour of the lung, and typically presents as single discrete coin lesions on imaging. Multiple SP is an exceedingly rare entity and thus reported sparingly. We review the literature on multiple SP, their clinical presentations, histopathology, relevant differential diagnoses and molecular histogenesis of this entity. SP has a predilection for East Asian origin females who have never smoked. Patients are either asymptomatic or have symptoms such as cough, haemoptysis that may be persistent, chest pain if involving the pleura and presents as discrete coin lesion on chest X-ray. Histologically, they are papillary, solid, angiomatoid or sclerotic, or combinations of these four basic patterns. Multiple lesions have the same or slightly different histological patterns. They can be distributed in either lung, in any lobe and can even be bilateral. AKT-1 molecular pathways are pivotal in their molecular pathogenesis. In this review, we further propose a classification based on five types of distribution of multiple SP.

An infectious clone of enterovirus 71(EV71) that is capable of infecting neonatal immune competent mice without adaptive mutations

Enterovirus 71 (EV71) is a major pathogen that causes hand, foot and mouth disease (HFMD), which is a life threatening disease in certain children. The pathogenesis of EV71-caused HFMD is poorly defined due to the lack of simple and robust animal models with severe phenotypes that recapitulate symptoms observed in humans. Here, we generated the infectious clone of a clinical isolate from a severe HFMD patient. Virus rescued from the cDNA clone was infectious in cell lines. When administrated intraperitoneally to neonatal ICR, BALB/c and C57 immune competent mice at a dosage of1.4 × 10⁴ pfu per mouse, the virus caused weight loss, paralysis and death in the infected mice after 4–5 days of infection. In the infected mice, detectable viral replication was detected in various tissues such as heart, liver, brain, lung, kidney, small intestine, leg skeletal muscle and medulla oblongata. The histology of the infected mice included massive myolysis, glomerular atrophy, villous blunting in small intestine, widened alveolar septum, diminished alveolar spaces and lymphocytes infiltration into the lung. By using the UV-inactivated virus as a control, we elucidated that the virus first amplified in the leg skeletal muscle tissue and the muscle tissue served as a primary viral replication site. In summary, we generated a stable EV71 infectious clone that is capable of infecting neonatal immune competent mice without adaptive mutations and provide a simple, valuable animal model for the studies of EV71pathogenesis and therapy.

Multicentre study on the consistency of PD-L1 immunohistochemistry as predictive test for immunotherapy in non-small cell lung cancer

AIMS

Investigate the impact of interlaboratory- and interobserver variability of immunohistochemistry on the assessment of programmed death ligand 1 (PD-L1) in non-small cell lung cancer (NSCLC).

METHODS

Two tissue microarrays (TMAs) were constructed from 50 (TMA-A) and 51 (TMA-B) resected NSCLC cases, and distributed among eight centres. Immunostaining for PD-L1 was performed using Agilent's 22C3 pharmDx Assay (pharmDx) and/or a 22C3 laboratory developed test (LDT). The interlaboratory variability of staining- and interobserver variability of scoring for PD-L1 were assessed in selected critical samples (samples at the cut-off of positivity) and non-critical samples. Also, PD-L1 epitope deterioration in time in stored unstained slides was analysed. Krippendorff's alpha values (0=maximal, 1=no variability) were calculated as measure for variability.

RESULTS

For interlaboratory variability of immunostaining, the percentage of PD-L1 positive cases among centres ranged 40%-51% (1% cut-off) and 23%-30% (50% cut-off). Alpha values at 1% cut-off were 0.88 (pharmDx) and 0.87 (LDT) and at 50% cut-off 0.82 (pharmDx) and 0.95 (LDT). Interobserver variability of scoring resulted in PD-L1 positive cases ranging 29%-55% (1% cut-off) and 14%-30% (50% cut-off) among pathologists. Alpha values were at 1% cut-off 0.83 (TMA-A) and 0.66 (TMA-B), and at 50% cut-off 0.77 (TMA-A) and 0.78 (TMA-B). Interlaboratory variability of staining was higher (p<0.001) in critical samples than in non-critical samples at 50% cut-off. Furthermore, PD-L1 epitope deterioration in unstained slides was observed after 12 weeks.

CONCLUSIONS

The results provide insight in factors contributing to variability of immunohistochemical assessment of PD-L1, and contribute to more reliable predictive testing for PD-L1.

Educational Case: Aspiration Pneumonia

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.¹

Evaluation of oxaliplatin-induced pulmonary toxicity in rats

Introduction

The mechanism of oxaliplatin (OXA) induced pulmonary toxicity is not fully understood.

Aim of the study

The present study was designed to investigate the pulmonary toxicity of OXA that has been reported in previous studies. Study design: animal experiments.

Material and methods

A total of 40 female Wistar rats were divided into 5 groups. In group 1, 5% glucose was injected intra-peritoneally; then the rats were sacrificed on day 14. OXA was administered in groups 2, 3, 4, and 5; then the animals were sacrificed on day 7 in group 2, day 14 in group 3, day 28 in group 4 and day 48 in group 5. The groups were further categorized as short-term administration and long-term administration groups. Furthermore, tissue glutathione peroxidase (GPX) activity was measured in all rats.

Results

The mean GPX activities were 0.66 U/mg in the sham group, 0.74 U/mg in the short-term groups, and 0.74 U/mg in the long-term groups. We found that long-term OXA administration causes pulmonary toxicity resulting in increased intra-alveolar/interstitial macrophages and interstitial pneumonia. Similarly, we found reduced and permanent tissue GPX activity in rats that received OXA in higher doses and for a long term.

Conclusions

Long-term OXA therapy causes toxic changes in the lung tissue.

NK cells inhibit anti-Mycobacterium bovis BCG T cell responses and aggravate pulmonary inflammation in a direct lung infection mouse model

Tuberculosis remains a threat to public health. The major problem for curing this disease is latent infection, of which the underlying mechanisms are still not fully understood. Previous studies indicate that natural killer (NK) cells do not play a role in inhibiting the growth of Mycobacterium tuberculosis in the lung, and recent studies have revealed that NK cells regulate the adaptive immunity during mycobacterial infection. By using a mouse model of direct lung infection with Mycobacterium bovis bacillus Calmette-Guerin (BCG), we found that the presence of NK cells postponed the priming and activation of T cells after BCG infection. In addition, depletion of NK cells before infection alleviated pulmonary pathology. Further studies showed that NK cells lysed BCG-infected macrophages in an NKG2D dependent manner. Thus, NK cells did not play a direct role in control BCG, but aggravated the pulmonary inflammation and impaired anti-BCG T cell immunity, likely through killing BCG-infected macrophages. Our results may have important implications for the design of immune therapy to treat tuberculosis.

Insights on pulmonary tumor thrombotic microangiopathy: a seven-patient case series

Pulmonary tumor thrombotic microangiopathy (PTTM) is a disease process wherein tumor cells are thought to embolize to the pulmonary circulation causing pulmonary hypertension (PH) and death from right heart failure. Presented herein are clinical, laboratory, radiographic, and histologic features across seven cases of PTTM. Highlighted in this publication are also involvement of pulmonary venules and clinical features distinguishing PTTM from clinical mimics.

We conducted a retrospective chart review of seven cases of PTTM from hospitals in the greater Los Angeles metropolitan area.

Patients in this series exhibited: symptoms of cough and progressive dyspnea; PH and/or heart failure on physical exam; laboratory abnormalities of anemia, thrombocytopenia, elevated LDH, and elevated D-dimer; chest computed tomography (CT) showing diffuse septal thickening, mediastinal and hilar lymphadenopathy and nodules; elevated pulmonary artery pressures on transthoracic echocardiogram and/or right heart catheterization; and presence of malignancy. Tumor emboli and fibrocellular intimal proliferation were seen in pulmonary arterioles, while two patients had pulmonary venopathy.

PTTM is a devastating disease occurring in patients with metastatic carcinoma. An early diagnosis is challenging. Understanding the clinical presentation of PTTM and distinguishing PTTM from clinical mimics may help achieve an early diagnosis and allow time for initiation of treatment.

Clinical significance of nestin and its association with survival in neuroendocrine lung tumours

Nestin is considered to be a cancer stem cell marker. Nestin expression in neuroendocrine tumours might be useful to predict prognosis and facilitate treatment planning. 88 patients with neuroendocrine lung tumours operated in the Department of Thoracic Surgery from 2007 to 2015 were included into the study. Immunohistochemical staining for nestin was performed. Clinicopathological and survival data were retrospectively analyzed. Nestin expression was detected in 15 (17%) specimens. Multivariate analysis showed that lymph node metastases (p = 0.0001; hazard ratio (HR) = 3.93; confidence interval (CI) 95%: 1.96-7.87), nestin expression (p = 0.034; HR = 2.30; CI 95%: 1.06-4.99) and patient's age (p = 0.024; HR = 1.04; CI 95%: 1.00-1.09) were independent negative prognostic factors. Nestin expression was significantly higher in large cell neuroendocrine carcinoma when compared with carcinoids (p = 0.001). Collected data support the thesis that nestin can be regarded as a biomarker in patients with neuroendocrine lung tumours.

Feline secondary spontaneous pneumothorax: a retrospective study of 16 cases (2000-2012)

OBJECTIVE

To describe the demographics, clinical characteristics, diagnostic findings, underlying etiologies, treatment, and outcome associated with secondary spontaneous pneumothorax (SSP) in cats; and to identify clinical feature differences among cats with asthma associated secondary spontaneous pneumothorax (AASSP) versus nonasthma-associated secondary spontaneous pneumothorax (NAASSP).

DESIGN

Retrospective case series.

SETTING

University teaching hospital.

ANIMALS

Sixteen client-owned cats with secondary spontaneous pneumothorax.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Domestic short hair was the predominant breed in this study (n = 15). The median age was 8 years old (range: 7 weeks to 17 years) with no sex predilection. Fourteen cats were affected by multi-lobar pulmonary pathology of infectious, inflammatory, or neoplastic causes. Asthma was the most common cause of spontaneous pneumothorax (25%). Ten of 12 treated cats survived the initial episode of spontaneous pneumothorax to discharge with medical management, including all 4 cats with AASSP. Reoccurrence was documented in 4 cats. Pulmonary lobectomy was curative for 1 cat with congenital accessory lung lobe emphysema. No difference in clinical presentation was identified between cats with AASSP and cats with NAASSP.

CONCLUSIONS

Feline SSP is frequently associated with extensive pulmonary pathology. Supportive medical management is most appropriate, except in rare cases with focal congenital abnormalities that may benefit from surgical intervention. AASSP appears to carry a good prognosis for short-term outcome (survival to discharge). Clinical assessment, imaging, and invasive diagnostics were required to differentiate between AASSP and NAASSP.

Dectin-1 induces M1 macrophages and prominent expansion of CD8+IL-17+ cells in pulmonary Paracoccidioidomycosis

Dectin-1, the innate immune receptor that recognizes β-glucan, plays an important role in immunity against fungal pathogens. Paracoccidioides brasiliensis, the etiological agent of paracoccidioidomycosis, has a sugar-rich cell wall mainly composed of mannans and glucans. This fact motivated us to use dectin-1-sufficient and -deficient mice to investigate the role of β-glucan recognition in the immunity against pulmonary paracoccidioidomycosis. Initially, we verified that P. brasiliensis infection reinforced the tendency of dectin-1-deficient macrophages to express an M2 phenotype. This prevalent antiinflammatory activity of dectin-1(-/-) macrophages resulted in impaired fungicidal ability, low nitric oxide production, and elevated synthesis of interleukin 10 (IL-10). Compared with dectin-1-sufficient mice, the fungal infection of dectin-1(-/-) mice was more severe and resulted in enhanced tissue pathology and mortality rates. The absence of dectin-1 has also impaired the production of T-helper type 1 (Th1), Th2, and Th17 cytokines and the activation and migration of T cells to the site of infection. Remarkably, dectin-1 deficiency increased the expansion of regulatory T cells and reduced the differentiation of T cells to the IL-17(+) phenotype, impairing the migration of IL-17(+)CD8(+) T cells and polymorphonuclear cells to infected tissues. In conclusion, dectin-1 exerts an important protective role in pulmonary paracoccidioidomycosis by controlling the innate and adaptive phases of antifungal immunity.

Subchronic pulmonary pathology, iron overload, and transcriptional activity after Libby amphibole exposure in rat models of cardiovascular disease

BACKGROUND

Surface-available iron (Fe) is proposed to contribute to asbestos-induced toxicity through the production of reactive oxygen species.

OBJECTIVE

Our goal was to evaluate the hypothesis that rat models of cardiovascular disease with coexistent Fe overload would be increasingly sensitive to Libby amphibole (LA)-induced subchronic lung injury.

METHODS

Male healthy Wistar Kyoto (WKY), spontaneously hypertensive (SH), and SH heart failure (SHHF) rats were intratracheally instilled with 0.0, 0.25, or 1.0 mg LA (with saline as the vehicle). We examined bronchoalveolar lavage fluid (BALF) and histological lung sections after 1 week, 1 month, or 3 months for pulmonary biomarkers and pathology. SHHF rats were also assessed at 6 months for pathological changes.

RESULTS

All animals developed concentration- and time-dependent interstitial fibrosis. Time-dependent Fe accumulation occurred in LA-laden macrophages in all strains but was exacerbated in SHHF rats. LA-exposed SHHF rats developed atypical hyperplastic lesions of bronchiolar epithelial cell origin at 3 and 6 months. Strain-related baseline differences existed in gene expression at 3 months, with persistent LA effects in WKY but not SH or SHHF rats. LA exposure altered genes for a number of pathways, including inflammation, immune regulation, and cell-cycle control. Cell-cycle control genes were inhibited after LA exposure in SH and SHHF but not WKY rats, whereas tumor suppressor genes were induced only in WKY rats. The inflammatory gene expression also was apparent only in WKY rats.

CONCLUSION

These data show that in Fe-overload conditions, progressive Fe accumulation occurs in fiber-laden macrophages within LA-induced lesions. Fe overload does not appear to contribute to chronic inflammation, and its role in hyperplastic lesion development requires further examination.