Immunological features in patients with pneumonitis due to influenza A H1N1 infection

BACKGROUND

Pneumonitis induced by pandemic influenza A H1N1 has a potential to cause respiratory failure, which is a risk factor for death. The underlying immunopathological mechanisms, however, have not yet been fully elucidated.

PATIENTS AND METHODS

We investigated changes in plasma cytokines, T cell subsets, and C-reactive protein (CRP) in 16 hospitalized patients with pneumonia caused by 2009 H1N1 influenza infection. The patients were classified into a severe disease group and a mild disease group according to PaO2.

RESULTS

Cytokine profiles showed no changes in interferon gamma (IFN-gamma), interleukin 6 (IL-6), IL-8, or transforming necrosis factor alpha (TNF-alpha) levels throughout the observation period. Transforming growth factor beta (TGF-beta1) was overproduced in the severe group but not in the mild group. Accordingly, we also found some signs of pulmonary fibrosis during the recovery period. Elevated CRP levels and lymphopenia were common in both the severe and the mild group. After treatment, there was a significant elevation in lymphocytes in both groups, but a significant decrease in CRP in the mild group. Lymphocyte counts and CRP levels rapidly recovered to normal levels in all survivors posttreatment; otherwise it seemed to be related to poor prognosis.

CONCLUSIONS

Serial measurements of cytokines showed that only TGF-beta1 was overproduced, possibly in relation to the early use of corticosteroids, which may have downregulated immune responses to H1N1 infection. Pretreatment TGF-beta1 plasma concentrations and absolute lymphocyte counts were independent predictors of severity. However, the role of elevated TGF-beta1 in H1N1 infection-associated pulmonary fibrosis requires further investigation.

Increased levels of soluble vascular endothelial cadherin are associated with poor outcome in severe sepsis

Endothelial cells are thought to play a key role in sepsis pathogenesis: vascular endothelial damage occurs in severe sepsis and multiple organ dysfunction. Soluble vascular endothelial cadherin (VE-cadherin) levels were investigated in a prospective study involving 28 consecutive critically ill patients with or without severe sepsis who were admitted to surgical intensive care; 13 healthy age-matched volunteers were included as controls. Soluble VE-cadherin levels increased significantly in patients with severe sepsis compared with ill patients without severe sepsis and healthy controls. There was a significant linear correlation between soluble VE-cadherin levels and illness severity scores. Soluble VE-cadherin levels were significantly higher in patients who died compared with survivors. In vitro cell culture showed that serum from patients with severe sepsis greatly decreased VE-cadherin staining at intercellular junctions and total VE-cadherin expression in human umbilical cord vein endothelial cells. These findings suggest that endothelial cells play an important role in the poor outcome of patients with severe sepsis.

Multimodality imaging of hypoxia in preclinical settings

Hypoxia has long been recognized to influence solid tumor response to therapy. Increasingly, hypoxia has also been implicated in tumor aggressiveness, including growth, development and metastatic potential. Thus, there is a fundamental, as well as a clinical interest, in assessing in situ tumor hypoxia. This review will examine diverse approaches focusing on the preclinical setting, particularly, in rodents. The strategies are inevitably a compromise in terms of sensitivity, precision, temporal and spatial resolution, as well as cost, feasibility, ease and robustness of implementation. We will review capabilities of multiple modalities and examine what makes them particularly suitable for investigating specific aspects of tumor pathophysiology. Current approaches range from nuclear imaging to magnetic resonance and optical, with varying degrees of invasiveness and ability to examine spatial heterogeneity, as well as dynamic response to interventions. Ideally, measurements would be non-invasive, exploiting endogenous reporters to reveal quantitatively local oxygen tension dynamics. A primary focus of this review is magnetic resonance imaging (MRI) based techniques, such as ¹⁹F MRI oximetry, which reveals not only hypoxia in vivo, but more significantly, spatial distribution of pO₂ quantitatively, with a precision relevant to radiobiology. It should be noted that preclinical methods may have very different criteria for acceptance, as compared with potential investigations for prognostic radiology or predictive biomarkers suitable for use in patients.

Tumor necrosis factor alpha increases epithelial barrier permeability by disrupting tight junctions in Caco-2 cells

The objectives of this study were to determine the effect of tumor necrosis factor alpha (TNF-alpha) on intestinal epithelial cell permeability and the expression of tight junction proteins. Caco-2 cells were plated onto Transwell microporous filters and treated with TNF-alpha (10 or 100 ng/mL) for 0, 4, 8, 16, or 24 h. The transepithelial electrical resistance and the mucosal-to-serosal flux rates of the established paracellular marker Lucifer yellow were measured in filter-grown monolayers of Caco-2 intestinal cells. The localization and expression of the tight junction protein occludin were detected by immunofluorescence and Western blot analysis, respectively. SYBR-Green-based real-time PCR was used to measure the expression of occludin mRNA. TNF-alpha treatment produced concentration- and time-dependent decreases in Caco-2 transepithelial resistance and increases in transepithelial permeability to the paracellular marker Lucifer yellow. Western blot results indicated that TNF-alpha decreased the expression of phosphorylated occludin in detergent-insoluble fractions but did not affect the expression of non-phosphorylated occludin protein. Real-time RT-PCR data showed that TNF-alpha did not affect the expression of occludin mRNA. Taken together, our data demonstrate that TNF-alpha increases Caco-2 monolayer permeability, decreases occludin protein expression and disturbs intercellular junctions.

Mechanism of the transforming growth factor-beta induction of fibronectin expression in hepatic stem-like cells

Transforming growth factor-beta1 (TGF-beta1) plays an important role in the fibrogenic process in the liver. The aim of the present study was to explore the action of TGF-beta1 on fibronectin expression in rat hepatic stem-like cells and the underlying mechanisms. The level of fibronectin expression was determined in hepatic stem-like cells (WB cells) before and after TGF-beta1 stimulation by RT-PCR and Western blot methods. Using immunogold transmission electron microscopy and the Western blot method, we observed the result of the expression and the distribution of cAMP, phosphorylated Smad3 and Smad7 before and after TGF-beta1 treatment. The levels of fibronectin expression in both mRNA and protein increased 4- to 5-fold after TGF-beta1 stimulation, reaching an optimum level after 8 h and then gradually falling back. Similarly, TGF-beta1 stimulation resulted in an increase of cAMP in WB cells, peaking at 8 h. After treatment with TGF-beta1 for 24 h, the expression of cAMP gradually decreased. In addition, we found that TGF-beta1 treatment also contributed to the increased expression and to changes in cellular distribution of phosphorylated Smad3 (translocation from the cytoplasm to the nucleus) and Smad7 (translocation from the nucleus to the cytoplasm) in WB cells. The present study demonstrates that TGF-beta is involved in the fibrogenic process in hepatic stem cells through up-regulation of fibronectin expression, and the mechanisms underlying this process may be associated with the activation of cAMP and Smad pathways.

Thrombomodulin improves early outcomes after intraportal islet transplantation

Primary islet nonfunction due to an instant blood mediated inflammatory reaction (IBMIR) leads to an increase in donor islet mass required to achieve euglycemia. In the presence of thrombin, thrombomodulin generates activated protein C (APC), which limits procoagulant and proinflammatory responses. In this study, we postulated that liposomal formulations of thrombomodulin (lipo-TM), due to its propensity for preferential uptake in the liver, would enhance intraportal engraftment of allogeneic islets by inhibiting the IBMIR. Diabetic C57BL/6J mice underwent intraportal transplantation with B10.BR murine islets. In the absence of treatment, conversion to euglycemia was observed among 29% of mice receiving 250 allo-islets. In contrast, a single infusion of lipo-TM led to euglycemia in 83% of recipients (p = 0.0019). Fibrin deposition (p < 0.0001), neutrophil infiltration (p < 0.0001), as well as expression TNF-alpha and IL-beta (p < 0.03) were significantly reduced. Significantly, thrombotic responses mediated by human islets in contact with human blood were also reduced by this approach. Lipo-TM improves the engraftment of allogeneic islets through a reduction in local thrombotic and inflammatory processes. As an enzyme-based pharmacotherapeutic, this strategy offers the potential for local generation of APC at the site of islet infusion, during the initial period of elevated thrombin production.

A low-noise differential microphone inspired by the ears of the parasitoid fly Ormia ochracea

A miniature differential microphone is described having a low-noise floor. The sensitivity of a differential microphone suffers as the distance between the two pressure sensing locations decreases, resulting in an increase in the input sound pressure-referred noise floor. In the microphone described here, both the diaphragm thermal noise and the electronic noise are minimized by a combination of novel diaphragm design and the use of low-noise optical sensing that has been integrated into the microphone package. The differential microphone diaphragm measures 1 x 2 mm(2) and is fabricated out of polycrystalline silicon. The diaphragm design is based on the coupled directionally sensitive ears of the fly Ormia ochracea. The sound pressure input-referred noise floor of this miniature differential microphone has been measured to be less than 36 dBA.

Visfatin expression is hormonally regulated by metabolic and sex hormones in 3T3-L1 pre-adipocytes and adipocytes

AIM

The novel adipokine visfatin has 'insulin-mimicking' effects and is increased in models of diet-induced obesity, but factors that regulate visfatin have not been fully elucidated.

METHODS

In order to determine visfatin regulation in adipocyte development and metabolism, as well as in pathophysiological conditions related to metabolic syndrome, endogenous visfatin expression was measured in 3T3-L1 pre-adipocytes and adipocytes using real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR).

RESULTS

A marked increase in visfatin expression was observed during differentiation, with a 2.2-fold increase between preconfluent and 2-day confluent cells even before differentiation was initiated. A further 4.1-fold increase was induced from day 0 to day 9 of differentiation (overall ninefold). Overnight incubation with dexamethasone (10(-8) to 10(-2) M) increased visfatin expression in both pre-adipocytes (1.5- to 3.3-fold, p < 0.05) and adipocytes (1.9-fold, p < 0.01). All other treatments decreased visfatin expression. In pre-adipocytes, visfatin expression decreased by 23% at a concentration of 1 microM insulin, 15% at 1-15 nM T3, 15% at 10 nM-1 microM progesterone, 33-44% at 10 nM-1 microM testosterone, 50% with palmitate and 30% with oleate (p < 0.05 for all). In adipocytes, insulin had a much greater effect, decreasing visfatin by 77% at 100 nM (p < 0.01), whereas oleate and sex hormones did not affect visfatin expression. However, tumor necrosis factor alpha, which had no effect on pre-adipocytes, significantly decreased visfatin in adipocytes by 26% at 10 ng/ml (p < 0.05). Interestingly, the thiazolidinedione (TZD) rosiglitizone also decreased visfatin by 28% at a concentration of 1 microM (p < 0.01).

CONCLUSION

In summary, while the mechanism of visfatin action remains to be elucidated, the clear effects of multiple hormones on visfatin expression support a physiological role.