Salbutamol up-regulates matrix metalloproteinase-9 in the alveolar space in the acute respiratory distress syndrome.

Objectives: Acute respiratory distress syndrome (ARDS) is characterized by alveolar-capillary barrier damage. Matrix metalloproteinases (MMPs) are implicated in the pathogenesis of ARDS. In the Beta Agonists in Acute Lung Injury Trial, intravenous salbutamol reduced extravascular lung water (EVLW) in patients with ARDS at day 4 but not inflammatory cytokines or neutrophil recruitment. We hypothesized that salbutamol reduces MMP activity in ARDS.

Methods: MMP-1/-2/-3/-7/-8/-9/-12/-13 was measured in supernatants of distal lung epithelial cells, type II alveolar cells, and bronchoalveolar lavage (BAL) fluid from patients in the Beta Agonists in Acute Lung Injury study by multiplex bead array and tissue inhibitors of metalloproteinases (TIMPs)-1/-2 by enzyme-linked immunosorbent assay. MMP-9 protein and activity levels were further measured by gelatin zymography and fluorokine assay.

Measurements and Main Results: BAL fluid MMP-1/-2/-3 declined by day 4, whereas total MMP-9 tended to increase. Unexpectedly, salbutamol augmented MMP-9 activity. Salbutamol induced 33.7- and 13.2-fold upregulation in total and lipocalin-associated MMP-9, respectively at day 4, compared with 2.0- and 1.3-fold increase in the placebo group, p < 0.03. Salbutamol did not affect BAL fluid TIMP-1/-2. Net active MMP-9 was higher in the salbutamol group (4222 pg/mL, interquartile range: 513-7551) at day 4 compared with placebo (151 pg/mL, 124-2108), p = 0.012. Subjects with an increase in BAL fluid MMP-9 during the 4-day period had lower EVLW measurements than those in whom MMP-9 fell (10 vs. 17 mL/kg, p = 0.004): change in lung water correlated inversely with change in MMP-9, r = -.54, p = 0.0296. Salbutamol up-regulated MMP-9 and down-regulated TIMP-1/-2 secretion in vitro by distal lung epithelial cells. Inhibition of MMP-9 activity in cultures of type II alveolar epithelial cells reduced wound healing.

Conclusions: Salbutamol specifically up-regulates MMP-9 in vitro and in vivo in patients with ARDS. Up-regulated MMP-9 is associated with a reduction in EVLW. MMP-9 activity is required for alveolar epithelial wound healing in vitro. Data suggest MMP-9 may have a previously unrecognized beneficial role in reducing pulmonary edema in ARDS by improving alveolar epithelial healing.

An unusual delayed complication of inferior alveolar nerve block

Systemic and localised complications after administration of local anaesthetic for dental procedures are well recognised. We present two cases of patients with trismus and sensory deficit that arose during resolution of trismus as a delayed complication of inferior alveolar nerve block.

Nontypeable Haemophilus influenzae clearance by alveolar macrophages is impaired by exposure to cigarette smoke

Nontypeable Haemophilus influenzae (NTHI) is an opportunistic gram-negative pathogen that causes respiratory infections and is associated with progression of respiratory diseases. Cigarette smoke is a main risk factor for development of respiratory infections and chronic respiratory diseases. Glucocorticoids, which are anti-inflammatory drugs, are still the most common therapy for these diseases. Alveolar macrophages are professional phagocytes that reside in the lung and are responsible for clearing infections by the action of their phagolysosomal machinery and promotion of local inflammation. In this study, we dissected the interaction between NTHI and alveolar macrophages and the effect of cigarette smoke on this interaction. We showed that alveolar macrophages clear NTHI infections by adhesion, phagocytosis, and phagolysosomal processing of the pathogen. Bacterial uptake requires host actin polymerization, the integrity of plasma membrane lipid rafts, and activation of the phosphatidylinositol 3-kinase (PI3K) signaling cascade. Parallel to bacterial clearance, macrophages secrete tumor necrosis factor alpha (TNF-alpha) upon NTHI infection. In contrast, exposure to cigarette smoke extract (CSE) impaired alveolar macrophage phagocytosis, although NTHI-induced TNF-alpha secretion was not abrogated. Mechanistically, our data showed that CSE reduced PI3K signaling activation triggered by NTHI. Treatment of CSE-exposed cells with the glucocorticoid dexamethasone reduced the amount of TNF-alpha secreted upon NTHI infection but did not compensate for CSE-dependent phagocytic impairment. The deleterious effect of cigarette smoke was observed in macrophage cell lines and in human alveolar macrophages obtained from smokers and from patients with chronic obstructive pulmonary disease.

Clinical grade allogeneic human mesenchymal stem cells restore alveolar fluid clearance in human lungs rejected for transplantation

The lack of suitable donors for all solid-organ transplant programs is exacerbated in lung transplantation by the low utilization of potential donor lungs, due primarily to donor lung injury and dysfunction, including pulmonary edema. The current studies were designed to determine if intravenous clinical-grade human mesenchymal stem (stromal) cells (hMSCs) would be effective in restoring alveolar fluid clearance (AFC) in the human ex vivo lung perfusion model, using lungs that had been deemed unsuitable for transplantation and had been subjected to prolonged ischemic time. The human lungs were perfused with 5% albumin in a balanced electrolyte solution and oxygenated with continuous positive airway pressure. Baseline AFC was measured in the control lobe and if AFC was impaired (defined as

Presentation of a plasmablastic lymphoma in a human immunodeficiency virus-positive patient after administration of an inferior alveolar dental block

Human immunodeficiency virus (HIV) is a serious worldwide healthcare problem with implications for all healthcare workers. The reported oral manifestations of the disease are numerous and have been categorised according to the strength of their association with HIV infection. Oral non-Hodgkin's lymphoma is strongly associated with HIV infection, and an increased incidence of such neoplasms is widely reported. This case report details the presentation of a rare subcategory of plasmablastic lymphoma in an HIV-positive patient after administration of an inferior alveolar dental block to facilitate extraction of mandibular teeth. This highly aggressive neoplasm is a large B-cell lymphoma with a predilection for the oral cavity. Unfortunately, the prognosis for such a tumour is poor as detailed in this case.

Cigarette smokers have exaggerated alveolar barrier disruption in response to lipopolysaccharide inhalation

RATIONALE: Cigarette smoke exposure is associated with an increased risk of the acute respiratory distress syndrome (ARDS); however, the mechanisms underlying this relationship remain largely unknown.

OBJECTIVE: To assess pathways of lung injury and inflammation in smokers and non-smokers with and without lipopolysaccharide (LPS) inhalation using established biomarkers.

METHODS: We measured plasma and bronchoalveolar lavage (BAL) biomarkers of inflammation and lung injury in smokers and non-smokers in two distinct cohorts of healthy volunteers, one unstimulated (n=20) and one undergoing 50 μg LPS inhalation (n=30).

MEASUREMENTS AND MAIN RESULTS: After LPS inhalation, cigarette smokers had increased alveolar-capillary membrane permeability as measured by BAL total protein, compared with non-smokers (median 274 vs 208 μg/mL, p=0.04). Smokers had exaggerated inflammation compared with non-smokers, with increased BAL interleukin-1β (p=0.002), neutrophils (p=0.02), plasma interleukin-8 (p=0.003), and plasma matrix metalloproteinase-8 (p=0.006). Alveolar epithelial injury after LPS was more severe in smokers than non-smokers, with increased plasma (p=0.04) and decreased BAL (p=0.02) surfactant protein D. Finally, smokers had decreased BAL vascular endothelial growth factor (VEGF) (p<0.0001) with increased soluble VEGF receptor-1 (p=0.0001).

CONCLUSIONS: Cigarette smoke exposure may predispose to ARDS through an abnormal response to a 'second hit,' with increased alveolar-capillary membrane permeability, exaggerated inflammation, increased epithelial injury and endothelial dysfunction. LPS inhalation may serve as a useful experimental model for evaluation of the acute pulmonary effects of existing and new tobacco products.

Sarcoidosis, alveolar β-actin and pulmonary fibrosis

BACKGROUND: Sarcoidosis is a multisystem granulomatous disease of unknown aetiology. Proteins present within the alveolar space early in sarcoidosis disease may provide an insight into novel mechanisms for the development of fibrotic disease and in particular pulmonary fibrosis.

METHODS: A modified two-dimensional difference gel electrophoresis protocol was applied to the human bronchoalveolar lavage fluid (hBALF) of four patients with non-persistent pulmonary interstitial disease at 4-year follow-up (defined as mild disease) and four patients who developed pulmonary interstitial disease at 4-year follow-up (defined as severe disease). The protein β-actin was identified by LC-MS/MS from a preparative gel and found to be significantly elevated in early lavages from the severe disease group. To look at the potential pro-fibrotic effects of this protein, primary human pulmonary fibroblasts (CCD-19Lu) were treated with recombinant β-actin following which qPCR and ELISA assays were used to measure any effects.

RESULTS: We found that β-actin levels were significantly elevated in early hBALF samples in patients who subsequently developed severe disease when compared to the mild group. Treating primary human pulmonary fibroblasts with recombinant β-actin led to enhanced gene expression of the pro-fibrotic markers alpha smooth muscle actin and collagen 1 as well as the increased secretion of interleukin-13 and metalloproteinases 3 and 9.

CONCLUSION: Free β-actin within the lungs of sarcoidosis patients potentially may contribute to disease pathogenesis particularly in the context of abnormal remodelling and the development of pulmonary fibrosis.

The comparative utility of fluorescence in situ hybridization and reverse transcription-polymerase chain reaction in the diagnosis of alveolar rhabdomyosarcoma.

Fluorescence in situ hybridization (FISH) for FOXO1 gene rearrangement and reverse transcription-polymerase chain reaction (PCR) for PAX3/7-FOXO1 fusion transcripts have become routine ancillary tools for the diagnosis of alveolar rhabdomyosarcomas (ARMS). Here we summarize our experience of these adjunct diagnostic modalities at a tertiary center, presenting the largest comparative series of FISH and PCR for suspected or possible ARMS to date. All suspected or possible ARMS tested by FISH or PCR for FOXO1 rearrangement or PAX3/7-FOXO1 fusion transcripts over a 7-year period were included. FISH and PCR results were correlated with clinical and histologic findings. One hundred samples from 95 patients had FISH and/or PCR performed. FISH had higher rates of technical success (96.8 %) compared with PCR (88 %). Where both tests were utilized successfully, there was high concordance rate between them (94.9 %). In 24 histologic ARMS tested for FISH or PCR, 83.3 % were translocation-positive (all for PAX3-FOXO1 by PCR) and included 3 histologic solid variants. In 76 cases where ARMS was excluded, there were 3 potential false-positive cases with FISH but none with PCR. PCR had similar sensitivity (85.7 %) and better specificity (100 %) in aiding the diagnosis of ARMS, compared with FISH (85 and 95.8 %, respectively). All solid variant ARMS harbored FOXO1 gene rearrangements and PAX3-FOXO1 ARMS were detected to the exclusion of PAX7-FOXO1. In comparative analysis, both FISH and PCR are useful in aiding the diagnosis of ARMS and excluding its sarcomatous mimics. FISH is more reliable technically but has less specificity than PCR. In cases where ARMS is in the differential diagnosis, it is optimal to perform both PCR and FISH: both have similar sensitivities for detecting ARMS, but FISH may confirm or exclude cases that are technically unsuccessful with PCR, while PCR can detect specific fusion transcripts that may be useful prognostically.

Meningeal alveolar soft part sarcoma confirmed by characteristic ASPCR1-TFE3 fusion

Sarcoma metastatic to the brain is uncommon and rarely occurs as the initial manifestation of tumor. Alveolar soft part sarcoma (ASPS) is a rare but well-studied subtype of sarcoma. A 39-year-old man presented with seizures due to a left temporal meningeal-enhancing lesion with striking brain edema on MRI. The patient underwent neurosurgical resection for suspected meningioma. Histology showed large tumor cells clustering and forming small nests, in places with pseudoalveolar pattern. Diastase-resistant periodic acid-Schiff revealed very rare granular and rod-like cytoplasmic inclusions. Immunohistochemistry showed convincing positivity only with vimentin and smooth muscle actin. The histological features were strongly suggestive of ASPS. At the molecular level RT-PCR and sequencing analysis demonstrated ASPCR1-TFE3 fusion confirming the histological diagnosis of ASPS. There was no evidence of primary extracranial tumor by physical examination and on chest and abdominal CT scan 11 months after presentation. ASPS typically arise from the soft tissues of the extremities and develop multiple metastatic deposits usually with a long clinical course. This case may represent primary meningeal ASPS although metastatic deposit from an undiscovered primary site cannot be entirely excluded.