Stimulatory response of neutrophils from periodontitis patients with periodontal pathogens

OBJECTIVE: Neutrophils play a crucial role in the defense of invading bacteria by releasing biologically active molecules. The response of peripheral blood neutrophils was studied in periodontitis-affected patients and in healthy controls towards stimulation to Porphyromonas gingivalis (Pg) and Actinobacillus actinomycetemcomitans (Aa) extracts. MATERIALS AND METHODS: Peripheral venous blood was drawn from 23 adult patients with moderate to advanced chronic periodontitis (probing depth >or=5 mm, attachment loss >or=3 mm), and 30 healthy volunteers. Neutrophil response followed by metalloproteinase-9 (MMP-9) and interleukin-8 (IL-8) secretion was assayed by zymography and enzyme-linked immunosorbent assay, respectively, on both whole blood and purified neutrophils. In addition to periodontal pathogen extracts, known stimulating agents were tested, such as Escherichia coli-lipopolysaccharide (LPS), phytohemagglutinin, and zymosan A. RESULTS: Neutrophil response, expressed as a secretion ratio under stimulated and non-stimulated conditions, measured in whole blood, showed no differences between periodontitis and healthy controls. Instead, in purified neutrophils from patients, MMP-9 exhibited a significantly higher secretion ratio with LPS and Pg (1.5- to 2-fold), whereas IL-8 showed a larger increase in secretion ratio (3- to 7-fold) in the presence of Pg, Aa, LPS, and zymosan A. CONCLUSION: Peripheral neutrophils of periodontitis-affected patients are more reactive as suggested by their significantly higher response toward periodontal pathogen extracts and other stimulating agents.     

Identification of the Molecular Determinants of the Antibacterial Activity of LmutTX,a Lys49 Phospholipase A2 Homologue Isolated from Lachesis muta muta Snake Venom (Linnaeus, 1766)

Snake venom phospholipases A₂ (PLA₂s) are responsible for numerous pathophysiological effects in snakebites; however, their biochemical properties favour antimicrobial actions against different pathogens, thus constituting a true source of potential microbicidal agents. This study describes the isolation of a Lys49 PLA₂ homologue from Lachesis muta muta venom using two chromatographic steps: size exclusion and reverse phase. The protein showed a molecular mass of 13,889 Da and was devoid of phospholipase activity on an artificial substrate. The primary structure made it possible to identify an unpublished protein from L. m. muta venom, named LmutTX, that presented high identity with other Lys49 PLA₂s from bothropic venoms. Synthetic peptides designed from LmutTX were evaluated for their cytotoxic and antimicrobial activities. LmutTX was cytotoxic against C2C12 myotubes at concentrations of at least 200 μg/mL, whereas the peptides showed a low cytolytic effect. LmutTX showed antibacterial activity against Gram‐positive and Gram‐negative bacteria; however, S. aureusATCC 29213 and MRSA strains were more sensitive to the toxin's action. Synthetic peptides were tested on S. aureus, MRSA and P. aeruginosaATCC 27853 strains, showing promising results. This study describes for the first time the isolation of a Lys49 PLA₂ from Lachesis snake venom and shows that peptides from specific regions of the sequence may constitute new sources of molecules with biotechnological potential.     

Inhibition of bacterial growth through LED (light-emitting diode) 465 and 630 nm: in vitro

Lasers in Medical Science - Photobiomodulation has been used to inactivate bacterial growth, in different laser or LED protocols. Thus, the aim of this study was to verify the inhibition of...     

The effect of photobiomodulation using low-level laser therapy on tooth sensitivity after dental bleaching: a systematic review

Lasers in Medical Science - The authors aimed to conduct a systematic review to assess data from the current literature on the effectiveness of low-level laser therapy (LLLT) in preventing tooth...     

The effects of photobiomodulation using LED on the repair process of skin graft donor sites

Lasers in Medical Science - The benefits of photobiomodulation (PBM) applied to wounds are well-described in the literature; however, its effects in skin graft donor sites have been poorly studied....     

Photodynamic therapy for squamous cell carcinoma of the head and neck: narrative review focusing on photosensitizers

Lasers in Medical Science - This narrative review aimed to evaluate the effectiveness of PDT in early or advanced squamous cell carcinoma of the head and neck (SCCHN). Scopus, MEDLINE/PubMed, and...     

Vaginal erbium laser for treatment of stress urinary incontinence: optimization of treatment regimen for a sustained long-term effect

Lasers in Medical Science - Stress urinary incontinence (SUI) is a common health problem that affects roughly 35% of women in the reproductive period. A prospective uncontrolled study was conducted...     

Traumatic brain injury biomarkers in pediatric patients: a systematic review

Neurosurgical Review - Traumatic brain injury (TBI) is the main cause of pediatric trauma death and disability worldwide. Recent studies have sought to identify biomarkers of TBI for the purpose of...