Clinical pathological characteristics and management of acute respiratory distress syndrome resulting from influenza A (H1N1) virus

Tumor Progression Locus 2 Protects against Acute Respiratory Distress Syndrome in Influenza A Virus-Infected Mice

Excessive inflammation in patients with severe influenza disease may lead to acute lung injury that results in acute respiratory distress syndrome (ARDS). ARDS is associated with alveolar damage and pulmonary edema that severely impair gas exchange, leading to hypoxia. With no existing FDA-approved treatment for ARDS, it is important to understand the factors that lead to virus-induced ARDS development to improve prevention, diagnosis, and treatment. We have previously shown that mice deficient in the serine-threonine mitogen-activated protein kinase, Tpl2 (MAP3K8 or COT), succumb to infection with a typically low-pathogenicity strain of influenza A virus (IAV; HKX31, H3N2 [x31]). The goal of the current study was to evaluate influenza A virus-infected Tpl2-/- mice clinically and histopathologically to gain insight into the disease mechanism. We hypothesized that Tpl2-/- mice succumb to IAV infection due to development of ARDS-like disease and pulmonary dysfunction. We observed prominent signs of alveolar septal necrosis, hyaline membranes, pleuritis, edema, and higher lactate dehydrogenase (LDH) levels in the lungs of IAV-infected Tpl2-/- mice compared to wild-type (WT) mice from 7 to 9 days postinfection (dpi). Notably, WT mice showed signs of regenerating epithelium, indicative of repair and recovery, that were reduced in Tpl2-/- mice. Furthermore, biomarkers associated with human ARDS cases were upregulated in Tpl2-/- mice at 7 dpi, demonstrating an ARDS-like phenotype in Tpl2-/- mice in response to IAV infection. IMPORTANCE This study demonstrates the protective role of the serine-threonine mitogen-activated protein kinase, Tpl2, in influenza virus pathogenesis and reveals that host Tpl2 deficiency is sufficient to convert a low-pathogenicity influenza A virus infection into severe influenza disease that resembles ARDS, both histopathologically and transcriptionally. The IAV-infected Tpl2-/- mouse thereby represents a novel murine model for studying ARDS-like disease that could improve our understanding of this aggressive disease and assist in the design of better diagnostics and treatments.

Serological ferritin, 100A12, procalcitonin and APACHEII score in prediction the prognosis of acute respiratory distress syndrome

Objective The aim of the present work was to investigate the prognostic value of serological ferritin, 100A12, procalcitonin (PCT) and APACHEII score in predicting death risk for patients with acute respiratory distress syndrome (ARDS).

Methods Forty eight ARDS patients were recruited from Feb. 2016 to Jan. 2019 from Lishui People’s Hospital. According to their prognosis (survival or death within 28 days), these 48 patients were further divided into the survival group (n=28) and death group (n=20). The serological levels of S100A12, PCT and ferritin of the 48 ARDS patients were examined within 24 hours after hospitalization. Demographic characteristics, serum S100A12, PCT and ferritin were compared between the two groups, and diagnostic analysis was performed to evaluate the clinical efficacy of these markers in predicting the death of ARDS patients.

Results The serum S100A12, ferritin and APACHEII scores of the death group were significantly higher than those of the survival group (p<0.05). However, serum PCT levels were not statistically different between the two groups (p>0.05). The death prediction sensitivity for serum S100A12, PCT, ferritin and APACHEII score were 65.0 (40.78-84.61)%, 60.00(36.05-80.88) %,75.0(50.90-91.34)% and 85.0(62.11-96.79)% respectively. The death prediction specificity for serum S100A12, PCT, ferritin and APACHEII score were 75.0(55.13-89.31)%, 60.00(36.05-80.88)%, 64.29(44.07-81.36)% and 82.14(63.11-93.94)%, respectively. The area under the ROC curve (AUC) for serum S100A12, PCT, ferritin and APACHEII score were 0.68(0.51-0.84), 0.63(0.46-0.79), 0.71(0.56-0.86) and 0.91(0.83-0.99) respectively.

Conclusion Serological ferritin, 100A12, PCT and APACHEII scores can be used as biomarkers to predict the death risk of ARDS patients.

Acute Respiratory Distress Syndrome (ARDS) from Endemic Influenza A/H1N1: Prehospital Management

Acute respiratory distress syndrome (ARDS) is a form of acute life threatening respiratory failure. In daily practice there is difficulty in diagnostic and therapeutic management of Acute respiratory distress syndrome (ARDS). We observed delay in diagnostic and therapeutic procedures in patients with clinical signs for the presence of severe respiratory disorders. Finding timely evidence of the presence the clinical signs of threatening ARDS and underlying diseases like influenza A/H1N1 during prehospital period in early stage of disease it is possible introduce early adequate treatment: high flow oxygen, fluid replacement and pharmacological and antiviral therapy. This measure can reduce high mortality in patients who develop ARDS. It is important to improve diagnostic criteria for a precise definition of ARDS and transfer it in practice of emergency and family medicine, microbiology, intensive care units, hospital departments of infectious and respiratory diseases. In this article we underlined the key elements of the new definition of ARDS, diagnostic criteria and the importance of early diagnosis in prehospital period following clinical feature and course (a presence of severe dyspnea) by adding chest x-ray and laboratory investigations.

Post-ARDS pulmonary fibrosis in patients with H1N1 pneumonia: role of follow-up CT

Purpose

Our aim was to evaluate the evolution of 20 patients with H1N1 pneumonia, focusing our attention on patients with severe clinical and radiological findings who developed post-acute respiratory distress syndrome (post-ARDS) pulmonary fibrosis.

Materials and methods

Twenty adult patients (nine women and 11 men; mean age 43.5±16.4 years) with a diagnosis of H1N1 infection confirmed by pharyngeal swab came to our attention from September to November 2009 and were followed up until September 2010. All patients were hospitalised in consideration of the severity of clinical findings, and all underwent chest X-ray. Twelve of them underwent at least one computed tomography (CT) scan of the chest.

Results

In 75% of cases (15/20), there was complete resolution of the clinical and radiological findings. Twenty-five percent of patients (5/20) developed acute respiratory distress syndrome (ARDS), which progressed to predominantly peripheral pulmonary fibrosis in 10% (2/20; one died and one had late-onset pulmonary fibrosis, documented on day 68). Moreover, in one patient with a CT diagnosis of pulmonary fibrosis, we observed progressive regression of radiological findings over 4 months of follow-up.

Conclusions

In patients with H1N1 pneumonia, post-ARDS pulmonary fibrosis is not a rare complication. Therefore, a CT scan should be performed in all patients with severe clinical findings. Our study demonstrated that in these patients, fibrosis could present a different spatial distribution and a different temporal trend, with delayed late onset; moreover, in one case, the signs of interstitial lung disease partially regressed over time. Therefore, CT should be considered not only in the diagnostic stage, but also during the follow-up.

Influenza induces endoplasmic reticulum stress, caspase-12-dependent apoptosis, and c-Jun N-terminal kinase-mediated transforming growth factor-β release in lung epithelial cells

Influenza A virus (IAV) infection is known to induce endoplasmic reticulum (ER) stress, Fas-dependent apoptosis, and TGF-β production in a variety of cells. However, the relationship between these events in murine primary tracheal epithelial cells (MTECS), which are considered one of the primary sites of IAV infection and replication, is unclear. We show that IAV infection induced ER stress marker activating transcription factor-6 and endoplasmic reticulum protein 57-kD (ERp57), but not C/EBP homologous protein (CHOP). In contrast, the ER stress inducer thapsigargin (THP) increased CHOP. IAV infection activated caspases and apoptosis, independently of Fas and caspase-8, in MTECs. Instead, apoptosis was mediated by caspase-12. A decrease in ERp57 attenuated the IAV burden and decreased caspase-12 activation and apoptosis in epithelial cells. TGF-β production was enhanced in IAV-infected MTECs, compared with THP or staurosporine. IAV infection caused the activation of c-Jun N-terminal kinase (JNK). Furthermore, IAV-induced TGF-β production required the presence of JNK1, a finding that suggests a role for JNK1 in IAV-induced epithelial injury and subsequent TGF-β production. These novel findings suggest a potential mechanistic role for a distinct ER stress response induced by IAV, and a profibrogenic/repair response in contrast to other pharmacological inducers of ER stress. These responses may also have a potential role in acute lung injury, fibroproliferative acute respiratory distress syndrome, and the recently identified H1N1 influenza-induced exacerbations of chronic obstructive pulmonary disease (Wedzicha JA. Proc Am Thorac Soc 2004;1:115-120) and idiopathic pulmonary fibrosis (Umeda Y, et al. Int Med 2010;49:2333-2336).