The potential role of amlodipine on experimentally induced bacterial rhinosinusitis / O papel potencial da amlodipina na rinossinusite bacteriana induzida experimentalmente

Abstract Introduction: Antibiotics are frequently used for the treatment of rhinosinusitis. Concerns have been raised regarding the adverse effects of antibiotics and growing resistance. The lack of development of new antibiotic compounds has increased the necessity for exploration of non-antibiotic compounds that have antibacterial activity. Amlodipine is a non-antibiotic compound with anti-inflammatory activity. Objective: In this study we aimed to investigate the potential role of amlodipine in the treatment of rhinosinusitis by evaluating its effects on tissue oxidative status, mucosal histology and inflammation. Methods: Fifteen adult albino guinea pigs were inoculated with Staphylococcus aureus and treated with saline, cefazolin sodium, or amlodipine for 7 days. The control group was composed by five healthy guinea pigs. Animals were sacrificed after the treatment. Histopathological changes were identified using Hematoxylin-Eosin staining. Inflammation was assessed by Polymorphonuclear Leukocyte infiltration density. Tissue levels of antioxidants (superoxide dismutase, glutathione) and an oxidative product (malondialdehyde) were determined. Results: In rhinosinusitis induced animals, amlodipine reduced loss of cilia, lamina propria edema and collagen deposition compared to placebo (saline) and although not superior to cefazolin, amlodipine decreased polymorphonuclear leukocyte infiltration. The superoxide dismutase activity and glutathione levels were reduced, whereas the malondialdehyde levels were increased significantly in all three-treatment groups compared to the control group. Amlodipine treated group showed significantly increased superoxide dismutase and glutathione levels and decreased malondialdehyde levels compared to all treatment groups. Conclusion: The non-antibiotic compound amlodipine may have a role in acute rhinosinusitis treatment through tissue protective, antioxidant and anti-inflammatory mechanisms.

Resumo Introdução: Antibióticos são frequentemente usados para o tratamento de rinossinusite. Questões têm sido levantadas sobre os efeitos adversos dos antibióticos e a resistência crescente. A falta de desenvolvimento de novos compostos antibióticos aumentou a necessidade da exploração de compostos não antibióticos que têm atividade antibacteriana. A amlodipina é um composto não antibiótico com atividade anti-inflamatória. Objetivo: O objetivo desse estudo foi investigar o papel potencial da amlodipina no tratamento da rinossinusite, avaliando seus efeitos sobre o estado oxidativo do tecido, histologia da mucosa e inflamação. Método: Quinze cobaias albinas adultas foram inoculadas com Staphylococcus aureus e tratadas com solução salina, cefazolina ou amlodipina durante sete dias. O grupo controle incluiu cinco cobaias saudáveis. Os animais foram sacrificados após o tratamento. Alterações histopatológicas foram identificadas com a coloração de hematoxilina-eosina. A inflamação foi avaliada pela densidade de infiltração de leucócitos polimorfonucleares. Foram determinados os níveis teciduais de antioxidantes (superóxido dismutase, glutationa) e um produto de oxidação (malondialdeído). Resultados: Em animais com rinossinusite induzida, a amlodipina reduziu a perda dos cílios, edema da lâmina própria e deposição de colágeno em comparação com o grupo placebo (solução salina) e embora não seja superior à cefazolina, a amlodipina diminuiu a infiltração de leucócitos polimorfonucleares. Os níveis de atividade da superóxido dismutase e glutationa foram reduzidos, enquanto os níveis de malondialdeído aumentaram significativamente nos três grupos de tratamento em comparação ao grupo controle. O grupo tratado com amlodipina apresentou aumento significante dos níveis de superóxido dismutase e glutationa e diminuição dos níveis de malondialdeído em comparação com todos os grupos de tratamento. Conclusão: O composto não antibiótico amlodipina pode ter um papel no tratamento da rinossinusite aguda através de mecanismos protetores de tecido, antioxidantes e anti-inflamatórios.

Current research status of non-antibiotic antibacterial therapies / 临床儿科杂志

With the inappropriate use of antibiotics, the situation of bacterial resistance is more and more severe. The emergence of multidrug-resistant (MDR) bacteria has made it difficult to cure the infections in clinical. For treatment the infections caused by MDR and reducucton of the generation of resistant bacteria, researchers are actively studying on the non-antibiotic substances for antibacterial activity. In this paper, the advances in those with conifrmed effects such as phage therapy, metal/chelation therapy, immunization therapy, photodynamic therapy, and nitric oxide (NO)-based therapies, small molecule inhibitors, antimicrobial peptides and Chinese herb were reviewed.

Antibacterial & antitoxic effects of the cardiovascular drug lacidipine in an animal model.

Background & objectives: Vibrio cholerae produces acute infection by liberating potent enterotoxin, called cholera toxin in human intestine. Cardiovascular drug lacidipine possessing powerful in vitro action against V. cholerae was tested to determine its possible activity against a toxigenic V. cholerae strain in an established animal model. Methods: In the rabbit intestine four loops were constructed, 3 of which were injected with over night grown V. cholerae 569B culture. Of these, two loops were simultaneously given graded doses (100, 200 μg) of lacidipine, one was left as such for a positive control. The first loop received sterile medium (negative control). After 18 h, contents of all the loops were examined for accumulation of fluid and number of viable cells. Results: Lacidipine when administrated with live V. cholerae 569B, caused a reduction in the number of viable bacteria along with amount of fluid in the loops. The amount of fluid and number of viable cells were much reduced in the loop that had 200 μg of lacidipine than the loop that received 100 μg of the drug. Interpretation & conclusions: Lacidipine has distinct inhibitory action against V. cholerae 569B with respect to both viability and production of cholera toxin in the rabbit ileum. Structural modifications of this compound may possibly lead to procurement of new potent antimicrobial drugs.