RESUMO
Infection of bone is a severe complication due to the variety of bacteria causing it, their resistance against classical antibiotics, the formation of a biofilm and the difficulty to eradicate it. Antimicrobial peptides (AMPs) are naturally occurring peptides and promising candidates for treatment of joint infections. This study aimed to analyze the effect of short artificial peptides derived from an optimized library regarding (1) antimicrobial effect on different bacterial species, (2) efficacy on biofilms, and (3) effect on osteoblastlike cells. Culturing the AMP-modifications with Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus (including clinical isolates of MRSA and MSSA) and Staphylococcus epidermidis identified one candidate that was most effective against all bacteria. This AMP was also able to reduce biofilm as demonstrated by FISH and microcalorimetry. Osteoblast viability and differentiation were not negatively affected by the AMP. A cation concentration comparable to that physiologically occurring in blood had almost no negative effect on AMP activity and even with 10% serum bacterial growth was inhibited. Bacteria internalized into osteoblasts were reduced by the AMP. Taken together the results demonstrate a high antimicrobial activity of the AMP even against bacteria incorporated in a biofilm or internalized into cells without harming human osteoblasts.
Assuntos
Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Doenças Ósseas Infecciosas/tratamento farmacológico , Doenças Ósseas Infecciosas/prevenção & controle , Sequência de Aminoácidos , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Biofilmes/efeitos dos fármacos , Doenças Ósseas Infecciosas/microbiologia , Células Cultivadas , Sistemas de Liberação de Medicamentos , Gentamicinas/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Osteoblastos/efeitos dos fármacos , Osteoblastos/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Staphylococcus epidermidis/efeitos dos fármacosRESUMO
BACKGROUND: In the dementia associated with acquired immunodeficiency syndrome (AIDS), indirect pathomechanisms are important mediators of progressive neuronal injury and variable candidate molecules of potential pathogenetic importance have been identified. MATERIALS AND METHODS: In an attempt to characterize additional mediators of human immunodeficiency virus type 1 (HIV-1)-induced neurotoxicity in vivo we have adapted the mRNA differential display technique to monitor the gene expression pattern in postmortem cortical tissue from AIDS patients with (n = 7) and without (n = 8) cognitive impairment as well as from HIV-1 seronegative controls (n = 4). RESULTS: Out of 29 differentially expressed cDNAs, two cDNA clones had confirmed variation of transcriptional regulation as assessed by reverse Northern analysis and gene-specific reverse transcription polymerase chain reaction (RT-PCR) and were up-regulated in the cortex of patients with AIDS dementia. Nucleotide sequence analysis of the two cDNAs identified known genes not previously associated with the pathogenesis of AIDS dementia, including the neurotrophin receptor tyrosine kinase receptor B (TrkB) and the potassium channel human open rectifyer K+ channel (ORK) homologous open reading frame (HOHO1). CONCLUSIONS: The altered expression of these transcripts may contribute to AIDS dementia through the enhancement of microglial activation and immunologic nitric oxide synthase (iNOS) activity by abnormal neurotrophic regulation and interference with membrane excitability through disturbance of local ion homeostasis.