Human metapneumovirus (HMPV) shares clinical and epidemiological characteristics with well-known respiratory syncytial virus (RSV). The aim of this study was to investigate the clinical and epidemiological differences between HMPV- and RSV-induced wheezing illnesses. A total of 1,008 nasopharyngeal aspirate specimens was collected from 1,008 pediatric patients hospitalized with acute respiratory tract infection at Inje University Sanggye Paik Hospital from December 2003 to April 2008, and tested for seven common respiratory viruses. Conditions classified as wheezing illness were bronchiolitis, reactive airways disease, and bronchial asthma. HMPV caused a significantly lower proportion of wheezing illness when compared to RSV (48.1% vs. 82.2%, P<0.05). HMPV-induced wheezing illness occurred predominantly in older patients when compared to RSV patients (P<0.001). RSV infections peaked in the fall and winter followed by peaks of HMPV infection in winter and spring. Eosinophil counts were significantly higher (P<0.01) in RSV patients when compared to HMPV patients. These results show that human metapneumovirus patients exhibit several different clinical and epidemiological characteristics, such as higher proportion of wheezing illness, age and seasonal incidence, and eosinophil counts, when compared to RSV patients.

These findings suggest that serum EDN is a useful marker for identifying disease activity in children with asthma. EDN levels may better reflect disease severity than ECP levels or total eosinophil counts.

The regeneration of mitochondria by regulated biogenesis plays an important homeostatic role in cells and tissues and furthermore may provide an adaptive mechanism in certain diseases such as sepsis. The heme oxygenase (HO-1)/carbon monoxide (CO) system is an inducible cytoprotective mechanism in mammalian cells. Natural antioxidants can provide therapeutic benefit, in part, by inducing the HO-1/CO system. This study focused on the mechanism by which the natural antioxidant quercetin can induce mitochondrial biogenesis in HepG2 cells. We found that quercetin treatment induced expression of mitochondrial biogenesis activators (PGC-1α, NRF-1, TFAM), mitochondrial DNA (mtDNA), and proteins (COX IV) in HepG2 cells. The HO inhibitor SnPP and the CO scavenger hemoglobin reversed the effects of quercetin on mitochondrial biogenesis in HepG2 cells. The stimulatory effects of quercetin on mitochondrial biogenesis could be recapitulated in vivo in liver tissue and antagonized by SnPP. Finally, quercetin conferred an anti-inflammatory effect in the liver of mice treated with LPS and prevented impairment of mitochondrial biogenesis by LPS in vivo. These salutary effects of quercetin in vivo were also antagonized by SnPP. Thus, our results suggest that quercetin enhances mitochondrial biogenesis mainly via the HO-1/CO system in vitro and in vivo. The beneficial effects of quercetin may provide a therapeutic basis in inflammatory diseases and sepsis.

No abstract

Despite asthma being the most common chronic childhood ailment, there is still much to learn about the disease. Early childhood infections with well-known or emerging viruses can lay the pathophysiologic framework for asthma development and exacerbation later in life, which may be due partly to alteration of the airway microbiome. Once asthma is established, acute exacerbations are usually associated with infections with respiratory viruses, such as rhinoviruses (RVs). Once again, there are bidirectional interactions between viruses and airway bacteria that appear to influence the severity of illness and the likelihood of exacerbation. Studies employing recent advances in viral and bacterial identification analytic techniques will clarify these new concepts and may provide the basis for new treatments or prevention or respiratory infection-associated exacerbation. This paper is a review of the associations among respiratory viruses, bacteria, inflammatory mechanisms, and asthma exacerbation.