Introduction of human β-defensin-3 into cultured human keratinocytes and fibroblasts by infection of a recombinant adenovirus vector

Correlation Between Serum Levels of 25-Hydroxyvitamin D and Severity of Community-Acquired Pneumonia in Hospitalized Patients Assessed by Pneumonia Severity Index: An Observational Descriptive Study

Introduction Pneumonia severity index (PSI) is a prognostic index used for estimating the possibility of death due to community-acquired pneumonia. Vitamin D is a fat-soluble vitamin, essential for calcium and phosphate homeostasis. Vitamin D also has antimicrobial properties and according to recent studies, its deficiency may be correlated to an increased frequency of respiratory infections. The serum concentration of 25-hydroxyvitamin D (25(OH)D) is the best vitamin D status index reflecting vitamin D produced in the skin and offered from food and dietary supplements. Methods The study involved patients, who fulfilled the criteria of community-acquired pneumonia. The exclusion criteria were: patients <18 years old, severely immunocompromised patients, patients with tuberculosis, patients with malabsorption disorders, nursing home residents, patients with a history of malignancy, chronic renal or liver disease, patients with congestive health failure or cerebrovascular disease, and patients receiving vitamin D as a supplement. The following parameters, recorded on admission, were evaluated: age, sex, co-morbidity, residence in a nursing home, duration of symptoms, clinical symptoms, confusion, blood gas analysis, chest radiograph (pleural effusion), and laboratory parameters. The patients were classified in risk classes according to the PSI. Blood samples were collected within the first 48 hours of hospitalization. The serum levels of 25-hydroxyvitamin D were determined by electrochemiluminescence binding assay in Roche Cobas 601 immunoassay analyzer and mean serum levels of 25-hydroxyvitamin D in each risk class were calculated. For statistical analysis, the statistical program SPSS for Windows version 17.0 (Statistical Package for the Social Sciences, SPSS Inc., Chicago, IL) was used. Results A total of 46 patients, 28 males and 18 females, with a mean age of 71.5±17.57 years, hospitalized with community-acquired pneumonia, were included. Sixteen patients (35%) had a severe deficiency, with 25(OH)D levels <10 ng/ml, 17 patients (37%) had moderate deficiency with 25(OH)D levels between 10-20 ng/ml, and 13 patients (28%) had insufficiency with 25(OH)D levels between 20-29 ng/ml. According to the PSI, four (8.7%) patients with a mean age of 53.75±15.43 years were classified as risk class I, 10 (21.7%) patients with a mean age of 54.7±14.82 years as class II, 10 (21.7%) patients with a mean age of 68.41±3.96 years as class III, 17 (37%) patients with a mean age of 84.82±9.73 years as class IV, and five (10.9%) patients with a mean age of 80.2±9.41 years as class V. The mean levels of 25(OH)D were 19.11±11.24 ng/ml in class I, 16.81±8.94 ng/ml in class II, 16.65±9.18 ng/ml in class III, 14.76±10.22 ng/ml in class IV, and 7.49±4.41 ng/ml in class V. There was a positive correlation between low levels of 25(OH)D and the pneumonia severity and statistically significant difference between the mean levels of 25(OH)D in class V (7.49±4.41 ng/ml) compared to overall mean levels in classes I, II, III and IV (16.15±9.49 ng/ml), with p<0.05. Conclusions According to our results, there was a positive association between low levels of 25-hydroxyvitamin D and community-acquired pneumonia severity assessed by PSI. The determination of 25-hydroxyvitamin-D status, mostly in patients >60 years old, may prevent severe community-acquired pneumonia.

Antimicrobial peptide CAMA-syn expressed in pulmonary epithelium by recombination adenovirus inhibited the growth of intracellular bacteria

BACKGROUND

Intracellular bacteria, especially Mycobacterium tuberculosis, are important pathogenic microorganisms that endanger human health. Purified and synthesized cecropin A-magainin 2 (CAMA-syn) can exhibit a higher antibacterial activity and lower cytotoxicity. To enhance such antimicrobial potential, it would be desirable to deliver CAMA-syn expressed in lung epithelial cells by an adenovirus vector using gene therapy.

METHODS

A549 cells in vitro and lung epithelial cells in vivo were used to express CAMA-syn by transducing recombinant adenovirus Ad-SPC-CAMA/GFP, and the expression of CAMA-syn was determined by a reverse transcriptase-polymerase reaction (RT-PCR) and immunofluorescence. The antimicrobial activity in cells was investigated by colony-forming rate and growth curve. Forty Kunming mice of a Bacillus Calmette-Guerin (BCG) infection animal model were randomly divided into three groups: adenoviruses delivery of Ad-SPC-CAMA/GFP, Ad-CMV-CAMA/GFP and empty-virus Ad-CMV-GFP. The expression of CAMA-syn in mice was confirmed by RT-PCR and immunofluorescence. After tracheal injection of adenoviral vector for 3 days, lungs from the mouse model were extracted and homogenized for detection of colony-forming efficiency.

RESULTS

CAMA-syn expressed in lung epithelial cells A549 conferred antimicrobial activity against a series of bacteria, including Salmonella abortusovis and BCG. The results obtained in vivo showed that the colony-forming rate of Ad-SPC-CAMA/GFP (74.54%) and Ad-CMV-CAMA/GFP (62.31%) transduced into mice was significantly lower than that of the control group.

CONCLUSIONS

Lung epithelial-specific expression of antimicrobial peptide CAMA-syn mediated by adenovirus suppressed the growth of intracellular bacteria, providing a promising approach for the control of refractory intracellular infection.

In vitro and in vivo properties of the bovine antimicrobial peptide, Bactenecin 5

Antimicrobial peptides (AMP), part of the innate immune system, are well studied for their ability to kill pathogenic microorganisms. However, many also possess important immunomodulatory effects, and this area has potential for the development of novel therapies to supplement traditional methods such as the use of antibiotics. Here, we characterise the microbicidal and immunomodulatory potential of the proline-rich bovine AMP, Bactenecin 5 (Bac5). We demonstrate broad antimicrobial activity, including against some mycobacterial species, which are important pathogens of fish, cattle and humans. Bac5 is able to activate macrophage-like THP-1 cells and can synergistically trigger the upregulation of tnf-α when co-stimulated with M. marinum. Furthermore, Bac5 sensitises A549 epithelial cells to stimulation with TNF-α. For the first time, we characterise the activity of Bac5 in vivo, and show it to be a potent chemokine for macrophages in the zebrafish (Danio rerio) embryo model of infection. Bac5 also supports the early recruitment of neutrophils in the presence of M. marinum. In the absence of host adaptive immunity, exogenous injected Bac5 is able to slow, although not prevent, infection of zebrafish with M. marinum.

Caspase-12 silencing attenuates inhibitory effects of cigarette smoke extract on NOD1 signaling and hBDs expression in human oral mucosal epithelial cells

Cigarette smoke exposure is associated with increased risk of various diseases. Epithelial cells-mediated innate immune responses to infectious pathogens are compromised by cigarette smoke. Although many studies have established that cigarette smoke exposure affects the expression of Toll-liked receptor (TLR), it remains unknown whether the nucleotide-binding oligomerization domain-containing protein 1 (NOD1) expression is affected by cigarette smoke exposure. In the study, we investigated effects of cigarette smoke extract (CSE) on NOD1 signaling in an immortalized human oral mucosal epithelial (Leuk-1) cell line. We first found that CSE inhibited NOD1 expression in a dose-dependent manner. Moreover, CSE modulated the expression of other crucial molecules in NOD1 signaling and human β defensin (hBD) 1, 2 and 3. We found that RNA interference-induced Caspase-12 silencing increased NOD1 and phospho-NF-κB (p-NF-κB) expression and down-regulated RIP2 expression. The inhibitory effects of CSE on NOD1 signaling can be attenuated partially through Caspase-12 silencing. Intriguingly, Caspase-12 silencing abrogated inhibitory effects of CSE on hBD1, 3 expression and augmented induced effect of CSE on hBD2 expression. Caspase-12 could play a vital role in the inhibitory effects of cigarette smoke on NOD1 signaling and hBDs expression in oral mucosal epithelial cells.

Human beta defensin-4 and keratinocyte growth factor gene expression in cultured keratinocyte and fibroblasts of burned patients

PURPOSE

To evaluate KGF and human beta defensin-4 (HBD-4) levels produced by dermic fibroblasts and keratinocytes cultivated from burned patients' skin samples.

METHODS

Keratinocytes and fibroblasts of 10 patients (four major burns, four minor burns and two controls) were primarily cultivated according to standard methods. HBD-4 and KGF genes were analyzed by quantitative PCR.

RESULTS

In fibroblasts, KGF gene expression was 220±80 and 33.33±6.67 (M±SD; N=4), respectively for major and minor burn groups. In keratinocytes, KGF gene expression was 11.2±1.9 and 3.45±0.37 (M±SD; N=4), respectively for major and minor burn groups. In fibroblasts, HBD-4 gene expression was 15.0±4.0 and 11.5±0.5 (M±SD; N=4), respectively for major and minor burn. In keratinocyte, HBD-4 gene expression was 0.0±0.0 and 13.4±4.8 (M±SD; N=4), respectively for major and minor burn.

CONCLUSIONS

KGF expression was increased in burn patient fibroblasts compared to control group. In keratinocytes culture, KGF suppression is inversely proportional to burn extension; it is active and increased in major burn but decreased in minor burn. HBD-4 expression was increased in fibroblasts and decreased in keratinocytes from all burned patients.

Inhibition of Pseudomonas aeruginosa with a recombinant RNA-based viral vector expressing human β-defensin 4

Background

Harassed with extensive epithelial burn wounds, patients can be affected by complications, such as infection, hypovolemic shock, hypothermia, and respiratory failure. Immediate first aid and followed supportive cares are critical for the prevention of severe complications. However, secondary bacterial infection is hard to be controlled in burn patients, and Pseudomonas aeruginosa (P. aeruginosa) is one of the top listed pathogens perturbing burn wounds beyond the antibiotics spectrum.

Results

To find the way for efficacious protection from the pseudomonas-mediated complications in burn patients, we assessed the in vitro and in vivo inhibitory values of human β-defensin 4 (hBD4), which is known as a member of the cationic, antimicrobial peptides found in human cells of many kinds. The Newcastle disease virus (NDV) was used as a viral vector for the expression of hBD4 in burn wounds. Expressed from the recombinant NDV (rNDV-hBD4), hBD4 effectively inhibited the pseudomonal growths in cell culture media. In a mouse model, severely burn-injured skin was recovered by the direct installation of the rNDV-hBD4 infected cells in the burn wounds whereas that of control mice remained severely damaged.

Conclusions

We suggest that the application of hBD4 may protect burn patients from secondary pseudomonal infection and provide a therapeutic potential for burn wound treatment.

Vitamin D's potential to reduce the risk of hospital-acquired infections

Health care–associated and hospital-acquired infections are two entities associated with increased morbidity and mortality. They are highly costly and constitute a great burden to the health care system. Vitamin D deficiency (< 20 ng/ml) is prevalent and may be a key contributor to both acute and chronic ill health. Vitamin D deficiency is associated with decreased innate immunity and increased risk for infections. Vitamin D can positively influence a wide variety of microbial infections.

Herein we discuss hospital-acquired infections, such as pneumonia, bacteremias, urinary tract and surgical site infections, and the potential role vitamin D may play in ameliorating them. We also discuss how vitamin D might positively influence these infections and help contain health care costs. Pending further studies, we think it is prudent to check vitamin D status at hospital admission and to take immediate steps to address existing insufficient 25-hydroxyvitamin D levels.

A Bioengineered Human Skin Tissue for the Treatment of Infected Wounds

BACKGROUND

Complex skin defects resulting from acute skin trauma and chronic, nonhealing wounds are life-threatening injuries. Infection is one of the most common obstacles to the healing of these types of wounds. Host defense peptides (HDPs) possessing a broad spectrum of activity against microorganisms and serving as innate immune modulators have emerged as potential treatment strategies for infected wounds.

THE PROBLEM

The increase in multidrug-resistant clinical bacterial isolates highlights the need for new and innovative anti-infective therapies for the treatment of both acute and chronic skin wounds.

BASIC/CLINICAL SCIENCE

To address the critical need for new therapeutic options to reduce infection and improve wound healing, a bioengineered skin substitute (BSS) tissue has been created to act as an anti-infective living human skin tissue that provides enhanced expression of the endogenous HDP, cathelicidin. To generate a BSS exhibiting these antimicrobial properties, the clinically tested NIKS progenitor cells were employed to provide a source of genetically uniform, nontumorigenic, pathogen-free human keratinocytes that are amenable to genetic engineering using nonviral means.

CLINICAL CARE RELEVANCE

Pathogenic bacterial strains are increasingly developing antibiotic resistance, thereby forcing the clinician to use potent antibiotics with deleterious effects on keratinocyte viability and migration. Therefore, an urgent need exists for new wound therapies that can circumvent many of the problems associated with current antibiotic treatments.

CONCLUSION

Enhanced expression of cathelicidin in a genetically engineered human BSS has been shown to inhibit the bacterial growth of a multidrug-resistant clinical strain of Acinetobacter baumannii in vivo, creating a new and innovative therapeutic option for combating these debilitating wound infections while also promoting healing.

Antimicrobial implications of vitamin D

Evidence exists that vitamin D has a potential antimicrobial activity and its deficiency has deleterious effects on general well-being and longevity. Vitamin D may reduce the risk of infection through multiple mechanisms. Vitamin D boosts innate immunity by modulating production of anti-microbial peptides (AMPs) and cytokine response. Vitamin D and its analogues via these mechanisms are playing an increasing role in the management of atopic dermatitis, psoriasis, vitiligo, acne and rosacea. Vitamin D may reduce susceptibility to infection in patients with atopic dermatitis and the ability to regulate local immune and inflammatory responses offers exciting potential for understanding and treating chronic inflammatory dermatitides. Moreover, B and T cell activation as well as boosting the activity of monocytes and macrophages also contribute to a potent systemic anti-microbial effect. The direct invasion by pathogenic organisms may be minimized at sites such as the respiratory tract by enhancing clearance of invading organisms. A vitamin D replete state appears to benefit most infections, with the possible noteworthy exception of Leishmaniasis. Antibiotics remain an expensive option and misuse of these agents results in significant antibiotic resistance and contributes to escalating health care costs. Vitamin D constitutes an inexpensive prophylactic option and possibly therapeutic product either by itself or as a synergistic agent to traditional antimicrobial agents. This review outlines the specific antimicrobial properties of vitamin D in combating a wide range of organisms. We discuss the possible mechanisms by which vitamin D may have a therapeutic role in managing a variety of infections.