Clinical characteristics and prognostic risk factors of healthcare-associated pneumonia in a Korean tertiary teaching hospital.

The 2016 American Thoracic Society and Infectious Diseases Society of America (ATS/IDSA) guidelines removed the concept of healthcare-associated pneumonia (HCAP). We examined whether the 2016 ATS/IDSA guidelines are applicable in Korea.We conducted a retrospective, observational study of pneumonia patients who were hospitalized at a tertiary teaching hospital from March 2012 to February 2014. Identified pathogens that were not susceptible to ß-lactams, macrolides, and fluoroquinolones were defined as community-acquired pneumonia drug-resistant pathogens (CAP-DRPs). We analyzed the risk factors for 28-day mortality and the occurrence rate of CAP-DRPs.Of the 1046 patients, 399 were classified with HCAP and 647 with CAP. HCAP patients were older and had more comorbidities than CAP patients. Initial pneumonia severity index (PSI) was higher in patients with HCAP than with CAP. HCAP was associated with not only an increased rate of CAP-DRPs (HCAP, 19.8%; CAP, 4.0%; P < .001) but also an increased rate of inappropriate initial antibiotic therapy (IIAT) (HCAP, 16.8%; CAP, 4.6%; P < .001). HCAP was also associated with an increased 28-day mortality rate compared with CAP (HCAP, 14.5%; CAP, 6.3%; P < .001). In a multivariable analysis, PSI was an independent risk factor for 28-day mortality in HCAP patients (odds ratio 1.02, 95% confidence interval 1.01-1.04). CAP-DRPs and IIAT were not associated with mortality.Patients with HCAP revealed higher rates of CAP-DRPs, IIAT, and mortality than patients with CAP. However, CAP-DRPs and IIAT were not associated with mortality. PSI was the main predictive factor for 28-day mortality in patients with HCAP.

p21-activated kinase 4 critically regulates melanogenesis via activation of the CREB/MITF and ß-catenin/MITF pathways.

p21-activated kinase 4 (PAK4) regulates a wide range of cellular events, including cytoskeletal remodeling, cell growth, and survival. Our previous study identified PAK4 as a key regulator of cAMP-response element-binding protein (CREB) that acts upstream of microphthalmia-associated transcription factor (MITF), a master transcription factor in melanogenesis. We therefore investigated the role of PAK4 in melanogenesis. Melanocytes express both PAK2 and PAK4 isoforms, but only RNA interference knockdown of PAK4 significantly influenced α-melanocyte-stimulating hormone (α-MSH)-induced melanogenesis in B16 melanoma cells. Consistent with this result, PAK4 inhibition by PF3758309, a potent ATP-competitive inhibitor of PAKs, suppressed not only α-MSH-induced melanogenesis in B16 melanoma and human epithelial melanocyte cells but also UVB-induced melanogenesis in the skin of melanin-possessing hairless mice (HRM-2) in a dose-dependent manner. Inhibition of PAK4 over several days markedly decreased the levels of CREB, MITF, and tyrosinase in both HRM-2 mice and B16 melanoma cells. Moreover, PAK4 knockdown and inhibition suppressed α-MSH-stimulated ß-catenin phosphorylation at serine 675 (S675) but enhanced phosphorylation at S33/37, an indicator for ubiquitination-dependent proteolysis. Together, our results provide evidence that PAK4 promotes α-MSH/UVB-induced melanogenesis via the CREB and Wnt/ß-catenin signaling pathways and suggest that PAK4 may be a potential therapeutic target in pigmentation disorders.

Accelerated aging phenotype in mice with conditional deficiency for mitochondrial superoxide dismutase in the connective tissue.

The free radical theory of aging postulates that the production of mitochondrial reactive oxygen species is the major determinant of aging and lifespan. Its role in aging of the connective tissue has not yet been established, even though the incidence of aging-related disorders in connective tissue-rich organs is high, causing major disability in the elderly. We have now addressed this question experimentally by creating mice with conditional deficiency of the mitochondrial manganese superoxide dismutase in fibroblasts and other mesenchyme-derived cells of connective tissues in all organs. Here, we have shown for the first time that the connective tissue-specific lack of superoxide anion detoxification in the mitochondria results in reduced lifespan and premature onset of aging-related phenotypes such as weight loss, skin atrophy, kyphosis (curvature of the spine), osteoporosis and muscle degeneration in mutant mice. Increase in p16(INK4a) , a robust in vivo marker for fibroblast aging, may contribute to the observed phenotype. This novel model is particularly suited to decipher the underlying mechanisms and to develop hopefully novel connective tissue-specific anti-aging strategies.

Transient receptor potential vanilloid-1 mediates heat-shock-induced matrix metalloproteinase-1 expression in human epidermal keratinocytes.

Transient receptor potential vanilloid-1 (TRPV1), a heat-gated channel, was recently found on human keratinocytes and the activation of epidermal TRPV1 was known to induce release of proinflammatory mediators. However, the functional consequences of TRPV1 activation in cutaneous physiology and pathology have not been elucidated clearly. In this study, we investigated the role of TRPV1 on the matrix metalloproteinase (MMP)-1 expression induced by heat shock in human epidermal keratinocytes. Heat shock induced the expression of MMP-1 mRNA and protein in a temperature-dependent manner in an immortalized human keratinocyte cell line (HaCaT) and normal human epidermal keratinocytes (NHK). Heat-shock-induced MMP-1 expression was decreased by treatment of the TRPV1 inhibitors (capsazepine and ruthenium red) or knockdown of TRPV1 using RNA interference in HaCaT cells. Overexpression of TRPV1 greatly increased heat-shock-induced MMP-1 promoter activity in HEK 293 cells. Furthermore, direct activation of TRPV1 by capsaicin, a TRPV1 agonist, increased MMP-1 expression. We found that heat shock induced calcium influx through TRPV1 and that extracellular calcium was necessary for heat-shock-induced MMP-1 expression in HaCaT cells. Taken together, our results suggest that heat-shock-induced MMP-1 expression is mediated by activation of TRPV1 and is dependent on a calcium-dependent signaling process in human epidermal keratinocytes.

All-trans retinoic acid antagonizes UV-induced VEGF production and angiogenesis via the inhibition of ERK activation in human skin keratinocytes.

Incident UV radiation leads to the upregulation of vascular endothelial growth factor (VEGF), a potent angiogenic factor, in human skin. However, the molecular basis of UV-induced angiogenesis in skin remains to be elucidated. In this study, we investigated the roles of UV exposure on cutaneous angiogenesis, its associated signaling mechanisms, and the effect of all-trans retinoic acid (tRA) on UV-induced vascularization, and VEGF expression. Using a human epidermal cell line, HaCaT, we found that UV induces VEGF mRNA and protein expression via the MAPK/ERK kinase-ERK1/2 (extracellular signal-regulated kinase 1/2) pathway but not via the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, and that tRA pretreatment significantly inhibits UV-induced VEGF overexpression and ERK1/2 activation. In human skin in vivo, we confirmed that skin vascularization significantly increased after a single exposure to UV, as was evidenced by a prominent increase in vessel size, vascular density, and in the cutaneous area occupied by vessels, and we found that these events are associated with VEGF upregulation. Topical pretreatment with tRA under occlusion inhibited not only UV-induced VEGF upregulation and angiogenesis with a significant reduction of vessel density but also UV-induced ERK1/2 activation in human skin. Collectively, our data demonstrate that tRA inhibits the UV-induced angiogenic switch via downmodulation of ERK1/2 activation and consecutive VEGF overexpression. These findings may help us understand the molecular mechanisms that regulate skin angiogenesis due to UV exposure, and provide evidence of the potential of tRA in terms of preventing angiogenesis-associated skin damage following exposure to UV irradiation.

The regulation of the expression of inducible nitric oxide synthase by Src-family tyrosine kinases mediated through MyD88-independent signaling pathways of Toll-like receptor 4.

Bacterial lipopolysaccharide (LPS) activates Toll-like receptor 4 (TLR4) leading to the expression of inflammatory gene products. Src-family tyrosine kinases (STKs) are known to be activated by LPS in monocytes/macrophages. Therefore, we determined the role of STKs in TLR4 signaling pathways and target gene expression in macrophages. The activation of NFkappaB, and p38 MAPK, and the expression of inducible nitric oxide synthase (iNOS) induced by LPS were not affected in macrophages deficient in three STKs (Lyn, Hck, and Fgr). These results suggest that the deletion of the three STKs among possibly nine STKs is not sufficient to abolish total activity of STKs possibly due to the functional redundancy of other STKs present in macrophages. However, two structurally unrelated pan-inhibitors of STKs, PP1 and SU6656, suppressed LPS-induced iNOS expression in MyD88-knockout as well as wild-type macrophages. The suppression of iNOS expression by the inhibitors was correlated with the downregulation of IFNbeta (a MyD88-independent gene) expression and subsequent decrease in STAT1 phosphorylation. Moreover, PP1 suppressed the expression of IFNbeta and iNOS induced by TRIF, a MyD88-independent adaptor of TLR4. PP1 suppressed STAT1 phosphorylation induced by LPS, but not by IFNbeta suggesting that STKs are involved in the primary downstream signaling pathways of TLR4, but not the secondary signaling pathways downstream of IFNbeta receptor. Together, these results demonstrate that STKs play a positive regulatory role in TLR4-mediated iNOS expression in a MyD88-independent (TRIF-dependent) manner. These results provide new insight in understanding the role of STKs in TLR4 signaling pathways and inflammatory target gene expression.

Aerosol-administered alpha-tocopherol attenuates lung inflammation in rats given lipopolysaccharide intratracheally.

Intrapulmonary administration of bacterial lipopolysaccharide (LPS) induces a well-characterized lung inflammatory response involving alveolar macrophage activation, proinflammatory cytokine elaboration, and neutrophil influx. Vitamin E, a lipophilic antioxidant consisting of a family that includes tocopherols and tocotrienols, has previously been shown to have a variety of anti-inflammatory effects, raising interest in its possible uses in disease prevention or therapy. Because aerosol delivery is a specific and rapid way to administer agents to the lungs, the authors undertook to determine whether inhaled vitamin E aerosols would have an anti-inflammatory effect in the lungs. Using a rat model of acute lung inflammation caused by intratracheally administered LPS (10 microg Pseudomonas aeruginosa LPS), the authors examined the effect of aerosol-administered vitamin E, in this case alpha-tocopherol, on several indices of lung inflammation which are increased by LPS treatment. It was found that inhaled alpha-tocopherol aerosol, but not inhaled alpha-tocopherol acetate aerosol, decreased tumor necrosis factor alpha (TNFalpha) and cytokine-induced neutrophil chemoattractant-1 (CINC-1) mRNA levels in lung tissue, TNFalpha and CINC-1 immunoreactive protein levels in lung lavage, and the number of neutrophils recoverable by lung lavage from rats given LPS intratracheally. These results contribute to the increasing body of work describing immunomodulatory functions of alpha-tocopherol, and support the idea that direct aerosol administration of alpha-tocopherol may play a beneficial role in strategies to control inflammatory lung illnesses.

Seborrheic keratosis in the Korean males: causative role of sunlight.

BACKGROUND/PURPOSE: Seborrheic keratoses (SKs) are common epidermal tumors in the white population over 40 years. The etiology of SKs is not well known; however, exposure to sunlight was suggested to play a role in the development of them. To our knowledge, no well-designed study has been undertaken in order to investigate the clinical characteristics of SKs in a brown-skinned Korean population. The aim of this study was to assess the prevalence and clinical features of SKs in the Korean males and to investigate the possible relationship of SKs with sun exposure and possible risk factors of developing SKs. METHODS: A total of consecutive 303 male volunteers, aged 40-70 years, were recruited from general community and public health centres. Each volunteer was interviewed regarding demographic data, sunlight sensitivity, lifetime cumulative sun exposure and smoking history. Skin examination was performed except for scalp, buttocks and genitals. All SKs were recorded about the anatomical distribution, the size of each lesion measured with a caliber, color and morphology. RESULTS: The mean overall prevalence of SKs in the Korean males, aged 40-70 years was 88.1%. A considerable increase in the prevalence of SKs was shown from 78.9% at 40 years to 93.9% at 50 years and 98.7% in those over 60 years. The mean number of lesions per person was 5.5 at 40 years, 9.2 at 50 years and 13.4 at 60 years. Seborrheic keratoses were considerably more frequent on exposed areas (0.47 +/- 0.06/percentage of body surface area, BSA) than partly exposed areas (0.04 +/- 0.01/percentage of BSA). The majority of lesions were concentrated on the face (0.98 +/- 0.09/percentage of BSA) and on the dorsum of each hand (0.51 +/- 0.08/percentage of BSA). The size of each lesion on exposed areas also became significantly larger by decade significantly (P < 0.01). The estimated area covered by SKs per percentage of BSA on exposed areas was 5.7-fold larger than that on partly exposed areas at 40 years, 11.2-fold larger at 50 years and 18.3-fold larger at 60 years. Aging by decade showed a 2.08-fold increased risk for SKs (n > or = 6) (95% CI, 1.07-4.08) at 50 years and a 3.47-fold risk (95% CI, 1.67-7.20) at 60 years on exposed areas compared with the 40-year age group, for developing many SKs (n > or = 6). Lifetime cumulative sunlight exposure of more than 6 h per day was associated with a 2.28-fold higher risk of SKs than a sun exposure of less than 3 h per day. A tendency for an odds ratio value reduction was found on increasing Fitzpatrick skin types I-III to VI, V; however, this was without statistical significance. CONCLUSIONS: Seborrheic keratoses are common in the Korean males, aged 40-70 years, and may be a major pigmentary problem. Both aging and cumulative sunlight exposure were found to be independent contributory factors.