Immunomodulatory Effects of Antimicrobial Drugs

Treating Pythiosis with Antibacterial Drugs Targeting Protein Synthesis: An Overview

This review article explores the effectiveness of antibacterial drugs that inhibit protein synthesis in treating pythiosis, a difficult-to-treat infection caused by Pythium insidiosum. The article highlights the susceptibility of P. insidiosum to antibacterial drugs, such as macrolides, oxazolidinones, and tetracyclines. We examine various studies, including in vitro tests, experimental infection models, and clinical case reports. Based on our synthesis of these findings, we highlight the potential of these drugs in managing pythiosis, primarily when combined with surgical interventions. The review emphasizes the need for personalized treatment strategies and further research to establish standardized testing protocols and optimize therapeutic approaches.

Local immunomodulatory effects of intracanal medications in apical periodontitis

The immune system is an extremely complex biological network that plays a crucial role in the hemostasis of periapical tissue, pathogenesis of apical periodontitis (AP) as well as periapical tissue healing. The successful elimination of microbial infections remains a significant challenge, mostly due to the ever-growing development of antimicrobial-resistant pathogens. The bacterial endurance in the root canal system contributes to features ranging from altered post-treatment healing to exacerbation of chronic periradicular immune response, that compromise the outcome of endodontic treatment. A highly effective strategy for combating infectious diseases and the associated inflammation-mediated tissue damage is to modulate the host immune response in conjunction with antimicrobial therapy. There are several medications currently used in endodontic treatment, however, they suffer various levels of microbial resistance and do not deliver all the required characteristics to simultaneously address both intracanal bacteria and periapical inflammation. Interaction of antimicrobial agents with the immune system can impact its function, leading to immune-suppressive or immune-stimulatory effects. The group of non-conventional antimicrobial medications, such as antimicrobial peptides, propolis, and nanomaterials, are agents that provide strong antimicrobial effectiveness and concomitant immunomodulatory and/or reparative effect, without any host tissue damages. Herein, we provide an overview of local immune modulation in AP and a comprehensive review of the immunomodulatory effect of antimicrobials intracanal medications applied in endodontics with specific emphasis on the antimicrobial nanomaterial-based approaches that provide immunomodulatory potential for successful clinical deployment in endodontics.

Effects of Pelargonium sidoides extract vs roxithromycin on chemokine levels in nasal secretions of patients with uncomplicated acute rhinosinusitis

BACKGROUND

Previous investigations suggest the use of extract from the roots of Pelargonium sidoides (EPs 7630) for the therapy of uncomplicated rhinosinusitis. The aim of this prospective study was to compare the effects of herbal drug EPs 7630 and antibiotic roxithromycin on chemokine production in nasal mucosa and clinical parameters in patients with uncomplicated acute bacterial rhinosinusitis (ABRS).

METHODS

Seventy-eight ABRS patients were divided into 26 patients receiving EPs 7630 tablets, 3 × 20 mg/day per os (group 1), 26 patients receiving roxithromycin tablets, 2 × 150 mg/day per os (group 2), both for 10 days, and 26 patients who received no therapy (Control group). We measured chemokine levels in nasal secretions by flow cytometry and assessed clinical parameters on day 0 and day 10 of investigation.

RESULTS

EPs 7630 increased concentrations of MCP-1 (P = .001) and IP-10 (P = .049) and decreased levels of MIP-1α (P < .001), ENA-78 (P < .001), and IL-8 (P < .001). Roxithromycin increased levels of IP-10 (P = .049) and decreased levels of MCP-1 (P < .001), MIP-1α (P < .016), ENA-78 (P < .001), and IL-8 (P < .001). Comparison of the non-treated patients' group with groups 1 and 2 revealed significant improvement of all clinical parameters in treated patients (P < .001), but therapy with roxithromycin resulted in better improvement in nasal symptoms and endoscopic findings than therapy with EPs 7630.

CONCLUSION

Our results suggest the presence of similar modulatory effects of both therapies on production of chemokines that regulate the function of neutrophils and monocytes in nasal mucosa. Roxithromycin shows better clinical efficacy than EPs 7630 in patients with uncomplicated ABRS.

LEVEL OF EVIDENCE

1b.

The Role of Specialized Pro-Resolving Mediators in Cystic Fibrosis Airways Disease

Cystic Fibrosis (CF) is a recessive genetic disease due to mutations of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene encoding the CFTR chloride channel. The ion transport abnormalities related to CFTR mutation generate a dehydrated airway surface liquid (ASL) layer, which is responsible for an altered mucociliary clearance, favors infections and persistent inflammation that lead to progressive lung destruction and respiratory failure. The inflammatory response is normally followed by an active resolution phase to return to tissue homeostasis, which involves specialized pro-resolving mediators (SPMs). SPMs promote resolution of inflammation, clearance of microbes, tissue regeneration and reduce pain, but do not evoke unwanted immunosuppression. The airways of CF patients showed a decreased production of SPMs even in the absence of pathogens. SPMs levels in the airway correlated with CF patients' lung function. The prognosis for CF has greatly improved but there remains a critical need for more effective treatments that prevent excessive inflammation, lung damage, and declining pulmonary function for all CF patients. This review aims to highlight the recent understanding of CF airway inflammation and the possible impact of SPMs on functions that are altered in CF airways.

Immunomodulatory Effects of Colistin on Macrophages in Rats by Activating the p38/MAPK Pathway

Objectives: Colistin has been identified in a Caenorhabditis elegans chemical screening as an immunostimulatory agent that activates the conserved p38/PMK-1 pathway and provides protection against pathogens. Here we aimed to extend those findings to a mammalian model and evaluate the immunomodulatory effects of colistin on rat macrophages.

Methods: Macrophages were isolated from Sprague-Dawley (SD) rat. The effects of colistin on the cytokine secretion, phagocytic activity and protein expression were determined by enzyme-linked immunosorbent assay (ELISA), flow cytometry, and Western blotting analysis, respectively. The relative microRNA expression was determined by microarray, and Kyoto Encylopedia of Genes and Genomes (KEGG) was used to identify potential signaling pathways.

Results: Our data showed that 5, 10, and 20 µg/ml colistin significantly increased the secretion of TNF-α, while 20 and 5 µg/ml colistin significantly increased the levels of IL-1β and IL-6, respectively. Flow cytometry results showed that the relative mean fluorescence intensity and percentage of phagocytosis in colistin treatment groups were significantly higher compared with the control group, while the increased phagocytosis phenomenon can be blocked by p38 inhibitor. The phagocytic ability of macrophages against Staphylococcus aureus was significantly increased after colistin treatment. Microarray and KEGG pathway analyses revealed that mitogen-activated protein kinase (MAPK), mammalian target of rapamycin (mTOR), chemokine, and B cell receptor were the main pathways involved in the colistin stimulation process. Western blotting analysis demonstrated that the phosphorylated p38 protein level of colistin treatment groups was increased in a dose dependent manner.

Conclusions: Present study is the first to demonstrate that colistin had immunomodulatory effects on macrophages in mammals, and the p38/MAPK pathway was involved in such colistin-induced immunomodulatory effect.