understanding the roles of cytokines and neutrophil activity and neutrophil apoptosis in the protective versus deleterious inflammatory response in pneumonia

SummaryInflammation is a double-edged sword in the outcome of pneumonia. On the one hand, an effective and timely inflammatory response is required to eliminate the invading respiratory pathogen. On the other, a toxic and prolonged inflammatory response may result in lung injury and poor outcomes, even in those receiving advanced medical care. This review focuses on recent understanding of the dynamics of the cytokine response, neutrophil activity, and responsiveness to cytokines and neutrophil lifespan as major elements of lung inflammation resulting in favorable or poor outcomes in lung infection primarily due to pneumococcus and influenza virus. Although some progress has been made in our understanding of the molecular mechanisms of the pneumonia inflammation axis composed of cytokines modulating neutrophil activation and neutrophil apoptosis, important questions remain to be answered. The degree of neutrophil activation, generation of reactive oxygen species, and the release of granule antimicrobial peptides play a key role in microbial pathogen clearance; however, prolonged neutrophil activation may contribute to lung injury and poor outcomes in pneumonia. Molecular markers of the mechanisms regulating neutrophil survival and apoptosis may help in the identification of novel therapeutic targets to modulate inflammation by inducing timely neutrophil apoptosis. A major task is to identify the mechanisms of dysregulation in inflammation leading to toxic responses, thereby targeting a biomarker and enabling timely therapies to modulate inflammation

Prevention of Diabetic Nephropathy by Sulforaphane: Possible Role of Nrf2 Upregulation and Activation

The present study was to investigate whether sulforaphane (SFN) can prevent diabetic nephropathy in type 1 diabetic mouse model induced by multiple low-dose streptozotocin. Diabetic and age-matched control mice were given SFN at 0.5 mg/kg body weight daily for 3 months. At the end of 3-month SFN treatment, the diabetic nephropathy, shown by renal inflammation, oxidative damage, fibrosis, and dysfunction, was significantly prevented along with an elevation of renal Nrf2 expression and transcription in diabetes/SFN group compared with diabetic group. However, this renal prevention by SFN was not seen when the 3-month SFN-treated diabetic mice were aged for additional 3 months without further SFN treatment. Nrf2-mediated renal protective effects in diabetes were evaluated in human renal tubular HK11 cells transfected with control and Nrf2 siRNA and treated with 27.5 mM mannitol or high glucose plus palmitate (300 μM). Blockade of Nrf2 expression completely abolished SFN prevention of the profibrotic effect induced by high glucose plus palmitate. These results support that renal Nrf2 expression and its transcription play important roles in SFN prevention of diabetes-induced renal damage. However, the SFN preventive effect on diabetes-induced renal pathogeneses is not sustained, suggesting the requirement of continual use of SFN for its sustained effect

Neutrophil Function in Elderly Patients Hospitalized with Community- Acquired Pneumonia

Background: Advanced age is associated with immunosenescence as well as increased risk for poor outcomes during episodes of community-acquired pneumonia (CAP). Data on neutrophil function in hospitalized elderly patients with CAP is lacking. In this study we compared neutrophil function in elderly and non-elderly hospitalized patients with CAP. Methods: Prospective study of healthy controls (HC) and patients hospitalized with CAP nonelderly (NE-CAP) and elderly (E-CAP). Blood samples were obtained on the day of hospitalization. The following neutrophil functional assays were performed: degranulation of secretory vesicles (CD35), degranulation of specific granules (CD66b), phagocytosis, and hydrogen peroxide (H2O2) production. The Mann-Whitney U-test was used to compare differences in neutrophil function. Results: A total of 12 HC, 28 NE-CAP, and 12 E-CAP were evaluated. There were no significant differences between NE-CAP and E-CAP patients in regard to CD35 expression (p=0.465), CD66b expression (p=0.601), phagocytosis (p=0.654), or H2O2 production (p=0.541) Conclusions: We failed to demonstrate any significant difference in neutrophil function in nonelderly versus elderly patients hospitalized with CAP in relation to membrane expression of CD35 and CD66b, phagocytosis, and respiratory burst. Abnormal neutrophil function is unlikely to be an important component of the immunosenescence described in elderly patients with CAP

Neutrophil function in elderly patients hospitalized with community-acquired pneumonia.

Background: Advanced age is associated with immunosenescence as well as increased risk for poor outcomes during episodes of community-acquired pneumonia (CAP). Data on neutrophil function in hospitalized elderly patients with CAP is lacking. In this study we compared neutrophil function in elderly and non-elderly hospitalized patients with CAP. Methods: Prospective study of healthy controls (HC) and patients hospitalized with CAP nonelderly (NE-CAP) and elderly (E-CAP). Blood samples were obtained on the day of hospitalization. The following neutrophil functional assays were performed: degranulation of secretory vesicles (CD35), degranulation of specific granules (CD66b), phagocytosis, and hydrogen peroxide (H2O2) production. The Mann-Whitney U-test was used to compare differences in neutrophil function. Results: A total of 12 HC, 28 NE-CAP, and 12 E-CAP were evaluated. There were no significant differences between NE-CAP and E-CAP patients in regard to CD35 expression (p=0.465), CD66b expression (p=0.601), phagocytosis (p=0.654), or H2O2 production (p=0.541) Conclusions: We failed to demonstrate any significant difference in neutrophil function in nonelderly versus elderly patients hospitalized with CAP in relation to membrane expression of CD35 and CD66b, phagocytosis, and respiratory burst. Abnormal neutrophil function is unlikely to be an important component of the immunosenescence described in elderly patients with CAP

Krϋppel-like factors (KLFs) in renal physiology and disease

Dysregulated Krϋppel-like factor (KLF) gene expression appears in many disease-associated pathologies. In this review, we discuss physiological functions of KLFs in the kidney with a focus on potential pharmacological modulation/therapeutic applications of these KLF proteins. KLF2 is critical to maintaining endothelial barrier integrity and preventing gap formations and in prevention of glomerular endothelial cell and podocyte damage in diabetic mice. KLF4 is renoprotective in the setting of AKI and is a critical regulator of proteinuria in mice and humans. KLF6 expression in podocytes preserves mitochondrial function and prevents podocyte apoptosis, while KLF5 expression prevents podocyte apoptosis by blockade of ERK/p38 MAPK pathways. KLF15 is a critical regulator of podocyte differentiation and is protective against podocyte injury. Loss of KLF4 and KLF15 promotes renal fibrosis, while fibrotic kidneys have increased KLF5 and KLF6 expression. For therapeutic modulation of KLFs, continued screening of small molecules will promote drug discoveries targeting KLF proteins. Keywords: Krϋppel-like factors (KLFs), Kidney disease, Podocytes, Renal tubule cells, Fibrosis, Interstitial inflammatio