Dimitrios Mikroulis

Neutrophil extracellular traps promote differentiation and function of fibroblasts.

Neutrophil activation by inflammatory stimuli and the release of extracellular chromatin structures (neutrophil extracellular traps – NETs) have been implicated in inflammatory disorders. Herein, we demonstrate that NETs released by neutrophils treated either with fibrosis‐related agents, such as cigarette smoke, magnesium silicate, bleomycin, or with generic NET inducers, such as phorbol 12‐myristate 13‐acetate, induced activation of lung fibroblasts (LFs) and differentiation into myofibroblast (MF) phenotype. Interestingly, the aforementioned agents or IL‐17 (a primary initiator of inflammation/fibrosis) had no direct effect on LF activation and differentiation. MFs treated with NETs demonstrated increased connective tissue growth factor expression, collagen production, and proliferation/migration. These fibrotic effects were significantly decreased after degradation of NETs with DNase1, heparin or myeloperoxidase inhibitor, indicating the key role of NET‐derived components in LF differentiation and function. Furthermore, IL‐17 was expressed in NETs and promoted the fibrotic activity of differentiated LFs but not their differentiation, suggesting that priming by DNA and histones is essential for IL‐17‐driven fibrosis. Additionally, autophagy was identified as the orchestrator of NET formation, as shown by inhibition studies using bafilomycin A1 or wortmannin. The above findings were further supported by the detection of NETs in close proximity to alpha‐smooth muscle actin (α‐SMA)‐expressing fibroblasts in biopsies from patients with fibrotic interstitial lung disease or from skin scar tissue. Together, these data suggest that both autophagy and NETs are involved not only in inflammation but also in the ensuing fibrosis and thus may represent potential therapeutic targets in human fibrotic diseases. Copyright

Organ Toxicity and Mortality in Propofol-Sedated Rabbits Under Prolonged Mechanical Ventilation

BACKGROUND: Prolonged administration of propofol at large doses has been implicated in propofol infusion syndrome in intensive care unit patients. In this study we investigated organ toxicity and mortality of propofol sedation at large doses in prolonged mechanically ventilated rabbits and determined the role of propofols lipid vehicle. METHODS: Eighteen healthy male rabbits were endotracheally intubated and sedated with propofol 2% (Group P), sevoflurane (Group S) or sevoflurane while receiving Intralipid 10% (Group SI). Sedation lasted 48 h or until death (Group P) or the maximum surviving period of Group P (Groups S and SI). The initial propofol infusion rate (20 mg · kg−1 · h−1) or sevoflurane concentration (1.5%) was adjusted, if needed, to maintain a standard level of sedation. Blood biochemical analysis was performed in serial blood samples and histologic examination in the heart, lungs, liver, gallbladder, kidneys, urinary bladder, and quadriceps femoris muscle at autopsy. RESULTS: The mortality rate was 100% (surviving period, 26–38 h) for Group P, whereas 0% for Groups S and SI. The initial propofol infusion rate had to be increased up to 65.7 ± 4.6 mg · kg−1 · h−1 and sevoflurane concentration up to 4%. Serum liver function indices, lipids and creatine kinase were significantly increased (P < 0.05) in Groups P and SI and lactate was increased only in Group P, whereas amylase was increased in all groups. In Group P, histologic examination revealed myocarditis, pulmonary edema with interstitial pneumonia, hepatitis, steatosis, and focal liver necrosis, cholangitis, gallbladder necrosis, acute tubular necrosis of the kidneys, focal loss of the urinary bladder epithelium, and rhabdomyolysis of skeletal muscles; in Group S, low-grade bronchitis and incipient inflammation of the liver and the kidneys; and in Group SI, low-grade bronchitis, liver steatosis and hepatitis, and incipient inflammation of the gallbladder, kidneys, and urinary bladder. CONCLUSIONS: Continuous infusion of 2% propofol at large doses for the sedation of rabbits undergoing prolonged mechanical ventilation induced fatal multiorgan dysfunction syndrome similar to the propofol infusion syndrome seen in humans. Our novel findings including lung, liver, gallbladder, and urinary bladder injury were also noted. The role of propofols lipid vehicle in the manifestation of the syndrome was minor. Sevoflurane proved to be a safe alternative medication for prolonged sedation.

Difficult airway and difficult intubation in postintubation tracheal stenosis: a case report and literature review

Management of a “difficult airway” remains one of the most relevant and challenging tasks for anesthesiologists and pulmonary physicians. Several conditions, such as inflammation, trauma, tumor, and immunologic and metabolic diseases, are considered responsible for the difficult intubation of a critically ill patient. In this case report we present the case of a 46-year-old male with postintubation tracheal stenosis. We will focus on the method of intubation used, since the patient had a “difficult airway” and had to be intubated immediately because he was in a life-threatening situation. Although technology is of utter importance, clinical examination and history-taking remain invaluable for the appropriate evaluation of the critically ill patient in everyday medical life. Every physician who will be required to perform intubation has to be familiar with the evaluation of the difficult airway and, in the event of the unanticipated difficult airway, to be able to use a wide variety of tools and techniques to avoid complications and fatality.

Surgical treatment of pulmonary aspergillosis/mycosis in immunocompromised patients

Invasive pulmonary aspergillosis is a severe complication in immunosuppressed patients. Surgical resection can be curative in certain patients after antifungal treatment. Over a 7-year period, ten patients with suspected invasive pulmonary aspergillosis of two university hospitals were retrospectively reviewed. A literature review was undertaken. Patients age was 48.1 years (mean); the cause of immunosuppression was a hematological disease with consecutive therapy in seven patients and chronically corticoid therapy in three patients. After an antifungal therapy, surgical resection was performed with lobectomy/segmentectomy in 60% and with wedge-resection in 40%. Postoperative course were uneventful in seven patients, two patients died due to infectional circumstances, and one patient was reoperated because of empyema. The underlying disease marked long-term follow-up. Resection of focal pulmonary invasive aspergillosis can be curative. Clinical circumstances and dissemination must be taken into consideration to indicate surgery. To point out the best pathway randomised prospective studies are necessary.

Tolerance to propofol's sedative effect in mechanically ventilated Rabbits.

Propofol is commonly used for the sedation of critically ill patients undergoing mechanical ventilation. These patients may develop tolerance during long-term administration. Here, we describe the development of tolerance to propofol’s sedative effect in rabbits during prolonged mechanical ventilation. Six healthy male New Zealand White rabbits were endotracheally intubated and received propofol by continuous IV infusion to maintain sedation for 48 h. The propofol infusion rate (IR) was adjusted to maintain the desired level of sedation. Assessments of the sedation level were made every 30 min or earlier if there were signs of awakening. Propofol concentrations were measured in arterial plasma after every other IR adjustment, provided there was an adequate level of sedation, using high performance liquid chromatography, and calculations of systemic clearance rates were made. The mortality rate was 100% with a survival period of 30.8 ± 6.0 h (mean ± sd). The course of IR adjustments followed a 5-phase pattern: 1) steady IR (mean ± sd duration; 1.2 ± 0.6 h), 2) increasing IR (9.4 ± 5.5 h), 3) steady high-IR (2.3 ± 1.2 h), 4) decreasing IR (13.7 ± 1.9 h), and 5) steady low-IR (5.0 ± 2.7 h). The course of propofol concentrations during the experiment in relation to propofol IR followed a 3-phase pattern: 1) steady concentration with increasing IRs (6.0 ± 2.7 h), 2) increasing concentrations with increasing IR (5.8 ± 2.5 h), and 3) increasing concentrations with decreasing IR (18.8 ± 3.3 h). Propofol systemic clearance rates were progressively increased for 6.0 ± 2.7 h and then gradually decreased for 24.6 ± 4.7 h. In conclusion, all rabbits developed tolerance to propofol’s sedative effect within the first hours of administration related to changes to the drug’s metabolic clearance.

Increased incidence of autoimmune markers in patients with combined pulmonary fibrosis and emphysema

BackgroundCombined pulmonary fibrosis and emphysema (CPFE) is an umbrella term encompassing upper lobe emphysema and lower lobe pulmonary fibrosis with pathogenesis elusive. The aim of our study was to investigate the incidence of autoimmune markers in patients with CPFE.MethodsIn this multicenter study we retrospectively evaluated records from patients with CPFE (n=40) and IPF (n=60) without emphysema. Baseline demographic characteristics, high-resolution computed tomography (HRCT), spirometry, histopathological, treatment, serum immunologic and survival data were investigated. B cell presence was estimated with CD20 immunostaining in representative lung biopsy samples from CPFE patients and control subjects.ResultsA statistically significant increased number of CPFE patients with elevated serum ANA with or without positive p-ANCA titers compared to patients with IPF without emphysema was observed. Patients with CPFE and positive autoimmune markers exhibited improved survival compared to patients with a negative autoimmune profile. A massive infiltration of clusters of CD20+ B cells forming lymphoid follicles within the fibrotic lung in CPFE patients with positive serum immunologic profile compared to patients with negative profile, was noted and positively correlated with improved survival.ConclusionsA significant proportion of patients with CPFE may present with underlying auto-immune disorders that may reside insidiously and be associated with favorable prognosis. Early identification of these patients using a panel of auto-antibodies may lead to more targeted and effective therapeutic applications.

Angiogenic Growth Factors in the Treatment of Peripheral Arterial Disease

Peripheral arterial disease (PAD) remains a major cause of morbidity. Despite advances in revascularisation procedures and medical treatment, limb salvage and relief of pain are still not satisfactory in patients with severe disease. This has prompted the exploration of alternative modes of treatment including enhancement of new vessel formation (angiogenesis). Angiogenic Growth Factors (AGF), mainly Vascular Endothelial Growth Factor (VEGF), basic Fibroblast Growth Factor (bFGF) and Hepatocyte Growth Factor (HGF) have emerged as exciting therapeutic modalities. Both experimental and clinical studies have demonstrated that topical (mainly intramuscular) AGF gene therapy results in improved peripheral vasculature and alleviation of symptoms. However, most clinical work is limited to small patient series and the long-term safety and efficacy are still unclear. Clinical benefit must be balanced against potential untoward effects, such as tumour growth and atherosclerotic plaque angiogenesis leading to plaque instability. VEGF is important in the pathogenesis of diabetic microvascular disease. Further studies are required before implementation of AGF therapy in clinical practice.

Acute fibrinous and organising pneumonia: a case report and review of the literature

IntroductionOrganising pneumonia is a distinct histopathological entity characterized by intra-alveolar buds of granulation tissue, called Masson bodies, which mainly comprise of activated fibroblasts and loose connective tissue. This histopathologic pattern has been described in idiopathic cases, characterizing cryptogenic organising pneumonia as well as in the context of pulmonary infection, drug-induced pneumonitis and following lung transplantation. Although distinct as a clinical and pathological entity, community organising pneumonia may present with atypical clinical and pathological features, such as intra-alveolar fillings of fibrin balls and organising tissue that resembles acute respiratory distress syndrome or diffuse alveolar damage. The latter characteristics constitute a recently described anatomoclinical entity called acute fibrinous and organising pneumonia.Case presentationHere, we describe a rare case of acute fibrinous and organising pneumonia, in an otherwise healthy 65-year-old Greek woman who complained of dry cough, fever, weight loss and progressive dyspnoea. She had never been a smoker. Her clinical symptoms showed a rapid deterioration in the two weeks before admission, despite a course of oral antibiotics. After excluding infection and malignancy with routine laboratory tests and flexible bronchoscopy, high resolution computed tomography and video assisted thoracoscopic lung biopsy were performed. Diagnosis was based on radiological features typical of community organising pneumonia coupled with pathologic features characteristic of acute fibrinous and organising pneumonia. The patient was treated with corticosteroids and showed excellent clinical and radiological response three months after treatment initiation.ConclusionAcute fibrinous and organising pneumonia is an extremely rare pathologic entity, often misdiagnosed as typical community organising pneumonia. To our knowledge, this is the seventh case of acute fibrinous and organising pneumonia in the literature, with no identifiable cause or association in a female patient, with no underlying lung disease or known exposures and with an unremarkable previous medical history. We highlight the need for careful review of lung biopsies from patients with clinical and radiologic characteristics typical of community organising pneumonia. Although it remains uncertain whether fibrin alters the favourable prognosis and treatment response of community organising pneumonia, it becomes obvious that a thorough pathologic review, apart from establishing the diagnosis of acute fibrinous and organising pneumonia, may predict a more unfavorable outcome therefore alerting the clinician to administer more aggressive and prolonged therapeutic regimens.

Increased Expression of Epidermal Growth Factor Receptor (EGF-R) in Patients with Different Forms of Lung Fibrosis

Introduction. Emerging evidence supports the role of epidermal growth factor-receptor (EGFR) in fibrogenesis. The aim of our study was to investigate the expression profiles of EGFR in three forms of IIPs, including idiopathic pulmonary fibrosis (IPF), cryptogenic organizing pneumonia (COP), and nonspecific interstitial pneumonia (NSIP). Patients and Methods. Twenty newly diagnosed patients with IPF, 15 with COP, and 15 with NSIP (cellular, n = 4 and fibrotic, n = 11) were investigated. Fifteen paraffin blocks obtained from the normal part of lungs removed for benign lesions were used as controls. Immunohistochemistry was carried out using specific monoclonal antibody. Results were verified by qRT-PCR. Results. A significant EGFR upregulation, both in protein and mRNA level, was observed in IPF, COP, and fibrotic NSIP samples compared to controls. EGFR was primarily localized in the hyperplastic alveolar epithelium surrounding areas of fibrosis in IPF, COP, and fibrotic NSIP samples, as assessed by double immunohistochemistry analysis with surfactant protein-A. EGFR mRNA levels were positively associated with indicators of lung fibrosis (type 1 collagen mRNA levels) and negatively correlated with functional prognostic parameters. Conclusions. We conclude that EGFR is upregulated in the hyperplastic alveolar epithelium in all three fibrotic forms of IIPs indicating a potential role during abnormal reepithelization.

Monitoring of brain oxygen saturation (INVOS) in a protocol to direct blood transfusions during cardiac surgery: a prospective randomized clinical trial

BackgroundBlood transfusions are common in cardiac surgery, but have been associated with increased morbidity and long-term mortality. Efforts to reduce blood product use during cardiac surgery include fluid restriction to minimize hemodilution, and protocols to guide transfusion decisions. INVOS is a modality that monitors brain tissue oxygen saturation, and could be useful in guiding decisions to transfuse. However, the role of INVOS (brain tissue oxygen saturation) as part of an algorithm to direct blood transfusions during cardiac surgery has not been evaluated. This study was conducted to investigate the value of INVOS as part of a protocol for blood transfusions during cardiac surgery.MethodsProspective, randomized, blinded clinical trial, on 150 (75 per group) elective cardiac surgery patients. The study was approved by the Institution Ethics committee and all patients gave written informed consent. Data were initially analyzed based on “intention to treat”, but subsequently were also analyzed “per protocol”.ResultsWhen protocol was strictly followed (“per protocol analysis”), compared to the control group, significantly fewer patients monitored with INVOS received any blood transfusions (46 of 70 patients in INVOS group vs. 55 of 67 patients in the control group, p = 0.029). Similarly, patients monitored with INVOS received significantly fewer units of red blood cell transfusions intraoperatively (0.20 ± 0.50 vs. 0.52 ± 0.88, p = 0.008) and overall during hospital stay (1.31 ± 1.20 vs. 1.82 ± 1.46, p = 0.024). When data from all patients (including patient with protocol violation) were analyzed together (“intention to treat analysis”), the observed reduction of blood transfusions in the INVOS group was still significant (51 of 75 patients transfused in the INVOS group vs. 63 of 75 patients transfused in the control group, p = 0.021), but the overall number of units transfused per patient did not differ significantly between the groups (1.55 ± 1.97 vs. 1.84 ± 1.41, p = 0.288).ConclusionsOur data suggest that INVOS could be a useful tool as part of an algorithm to guide decisions for blood transfusion in cardiac surgery. Additional data from rigorous, well designed studies are needed to further evaluate the role of INVOS in guiding blood transfusions in cardiac surgery, and circumvent the limitations of this study.Trial registrationClinicalTrials.gov: NCT00879463