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Asthma affects an estimated 300 million people worldwide and accounts for 1 of 250 deaths and 15 million disability-adjusted life years lost annually. Plastic-adherent bone marrow-derived cell (BMC) administration holds therapeutic promise in regenerative medicine. However, given the low cell engraftment in target organs, including the lung, cell replacement cannot solely account for the reported therapeutic benefits. This suggests that BMCs may act by secreting soluble factors. BMCs also possess antiinflammatory and immunomodulatory properties and may therefore be beneficial for asthma. Our objective was to investigate the therapeutic potential of BMC-secreted factors in murine asthma. In a model of acute and chronic asthma, intranasal instillation of BMC conditioned medium (CdM) prevented airway hyperresponsiveness (AHR) and inflammation. In the chronic asthma model, CdM prevented airway smooth muscle thickening and peribronchial inflammation while restoring blunted salbutamol-induced bronchodilation. CdM reduced lung levels of the T(H)2 inflammatory cytokines IL-4 and IL-13 and increased levels of IL-10. CdM up-regulated an IL-10-induced and IL-10-secreting subset of T regulatory lymphocytes and promoted IL-10 expression by lung macrophages. Adiponectin (APN), an antiinflammatory adipokine found in CdM, prevented AHR, airway smooth muscle thickening, and peribronchial inflammation, whereas the effect of CdM in which APN was neutralized or from APN knock-out mice was attenuated compared with wild-type CdM. Our study provides evidence that BMC-derived soluble factors prevent murine asthma and suggests APN as one of the protective factors. Further identification of BMC-derived factors may hold promise for novel approaches in the treatment of asthma.

Background: The eosinophil is a prominent cell in allergic lung inflammation and is exposed to a range of cytokines, including TNF-alpha, at the site of allergen challenge. Matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) produced by inflammatory cells are thought to play a crucial role in interstitial matrix turnover and tissue remodeling in acute and chronic lung diseases. In addition, protein kinase C is known to be important in MMP-9 expression and secretion., Objective: We investigated the regulation of eosinophil-derived MMP-9 and TIMP proteins by TNF-alpha., Methods: Using RT-PCR and gelatin zymography, we investigated the ability of human eosinophils to produce and secrete active MMP-9 on stimulation with TNF-alpha. We also studied the production of TIMP-1 and TIMP-2 in eosinophils by using Western blotting., Results: The gelatinolytic activity of MMP-9 in unstimulated eosinophils was low, but it increased by 95% after TNF-alpha stimulation. This increase was regulated at both the transcriptional and translational levels. The transcription inhibitor actinomycin D, the nuclear factor kappaB (NFkappaB) inhibitor N-CBZ-Leu-Leu-Leu-AL, the protein synthesis inhibitor cycloheximide, and the protein kinase C inhibitor H7 significantly decreased MMP-9 activity in TNF-alpha-treated cells. TIMP-1 and TIMP-2 gene expression and protein production varied significantly among different cell donors., Conclusion: Eosinophils, on stimulation with TNF-alpha, may play a major role in asthmatic airway remodeling through increased MMP-9 production at the inflammatory site.

The single channel inside-out patch clamp technique was used to characterize ion channels in the apical membranes of ragweed-sensitized and control canine tracheal epithelial cells maintained in primary culture. Patches were obtained from single isolated cells or from cells at the edges of confluent sheets. A new type of chloride channel was seen in sensitized cells but not in control cells. The channel showed inward rectification in symmetric chloride solutions with conductance varying from 95 pS to 52 pS over the range of -60 mV to 60 mV membrane potential. Channel gating was voltage dependent with maximal opening at about -30 mV. Kinetic analysis showed that distributions of closed and open times could both be well fitted by the sums of three exponential components. Rate constants for transitions between the states of a linear kinetic model were calculated, with only one rate being significantly voltage dependent. The possible significance of this channel is discussed.