Effects of amphotericin B on ion transport proteins in airway epithelial cells

Antibiotic Driven Changes in Gut Motility Suggest Direct Modulation of Enteric Nervous System

Antibiotic-mediated changes to the intestinal microbiome have largely been assumed to be the basis of antibiotic-induced neurophysiological and behavioral changes. However, relatively little research has addressed whether antibiotics act directly on the host nervous system to produce these changes. We aimed to identify whether acute exposure of the gastrointestinal tract to antibiotics directly modulates neuronally dependent motility reflexes, ex vivo. Motility of colon and jejunum segments in a perfusion organ bath was recorded by video and alterations to neuronally dependent propagating contractile clusters (PCC), measured using spatiotemporal maps of diameter changes. Short latency (<10 min) changes to PCC serve as an index of putative effects on the host nervous system. Bacitracin, penicillin V, and neomycin, all produced dose-dependent alterations to the velocity, frequency, and amplitude of PCC. Most significantly, colonic PCC velocity increased by 53% [probability of superiority (PS) = 87%] with 1.42 mg/ml bacitracin, 19% (PS = 81%) with 0.91 mg/ml neomycin, and 19% (PS = 86%) with 3.88 mg/ml penicillin V. Colonic frequency increased by 16% (PS = 73%) with 1.42 mg/ml bacitracin, 21% (PS = 79%) with 0.91 mg/ml neomycin, and 34% (PS = 85%) at 3.88 mg/ml penicillin V. Conversely, colonic amplitude decreased by 41% (PS = 79%) with 1.42 mg/ml bacitracin, 30% (PS = 80%) with 0.27 mg/ml neomycin and 25% (PS = 79%) at 3.88 mg/ml penicillin V. In the jejunum, antibiotic-specific changes were identified. Taken together, our findings provide evidence that acute exposure of the gastrointestinal lumen to antibiotics modulates neuronal reflexes. Future work should acknowledge the importance of this mechanism in mediating antibiotic-driven changes on gut-brain signaling.

The effect of topical amphotericin B on inflammatory markers in patients with chronic rhinosinusitis: a multicenter randomized controlled study

BACKGROUND

It has been suggested that an exaggerated immune response to fungi is crucial in the pathogenesis of chronic rhinosinusitis (CRS). Based on this rationale, the use of topical antifungals (amphotericin B) has been advocated. Studies on its clinical effectiveness are, however, contradictory.

OBJECTIVES

To examine the effect of nasal antifungal treatment on secreted mediators in samples of nasal lavage fluid from patients with CRS with or without nasal polyps (NP).

METHODS

Part two of a prospective double-blind, placebo-controlled multicenter clinical trial investigating the effect of 13 weeks of treatment with amphotericin B or placebo on the levels of pro-inflammatory cytokines, chemokines and growth factors (i.e., IL-1beta, IL-1RA, IL-2, IL-2R, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p40/p70 subunits), IL-13, IL-15, IL-17, TNF-alpha, IFN-alpha, IFN-gamma, G-CSF, GM-CSF, MIP-1alpha, MIP-1beta, IP-10, MIG, eotaxin, RANTES, MCP-1, MCP-2, MCP-3, VEGF, EGF, FGF-basic, HGF, Gro-alpha) and albumin via a fluorescent enzyme immunoassay in nasal lavage specimens of CRS patients with or without NP.

RESULTS

Topical amphotericin B had no significant effect on the level of any of the tested pro-inflammatory cytokines, chemokines, and growth factors in CRS nasal lavage samples. Treatment with placebo, however, increased the level of MIP-1alpha and MIP-1beta, which are mediators involved in wound healing.

CONCLUSIONS

Topical amphotericin B has no significant effect on activation markers of nasal inflammatory cells in chronic rhinosinusitis with or without nasal polyps.

[Postoperative application of amphotericin B nasal spray in chronic rhinosinusitis with nasal polyposis. Can recidive polyposis be prevented?]

Chronic rhinosinusitis affects 1-4% of the adult population. The aetiology of this multifactorial, chronic disease, which leads to a significant impairment of the quality of life, often accompanied by nasal polyposis, is not fully understood. In the past decade it was presumed that the disease, which causes characteristic eosinophilic infiltration of the nasal mucosa, is triggered by an enhanced (but not classical allergic IgE type) immune response.

AIM

If this supposition is correct, then it appears obvious that the administration of amphotericin B nasal spray in adequate concentration following endoscopic polypectomy should be advantageous for these patients, and might even reduce the number of recurrent cases.

METHODS

To check on this assumption, the authors conducted a prospective randomized placebo-controlled trial involving 33 patients, 30 of whom remained in the study throughout. Patients with nasal polyposis were operated on with an endoscopic technique between 1 November 2005 and 1 October 2006; one group of them (group A, 14 randomly selected patients) was treated with a nasal spray containing 5 mg/ml amphotericin B, while the placebo group (group B, 16 randomly selected patients) received a nasal spray lacking amphotericin B. The results were evaluated with the aid of a modified Lund-Mackay CT score, the SNAQ-11 test (which evaluates changes in the symptoms), the life-quality test and endoscopy. The SPSS 14.0 for Windows program was utilized to process the data of examinations performed preoperatively and one year postoperatively.

RESULTS

The CT scores of the group A patients exhibited wide scattering without signs of recovery one year after the operation. The CT scores of the group B patients indicated a slight improvement, though this did not prove significant in relation to group A. Both the SNAQ-11 test and the life-quality test revealed a significant improvement in each group, but the degrees of change in these tests did not significantly differ between the two groups of patients. The endoscopic findings indicated a slight improvement to the advantage of the amphotericin B-treated group 12 months after the operation.

CONCLUSION

These results lead to the conclusion that the administration of amphotericin B nasal spray to patients operated on for nasal polyposis does not give rise to a significant alteration in CT scores, clinical symptoms, or quality of life. The more favourable clinical aspects observed in the amphotericin B-treated group during the endoscopic follow-up did not correspond to an improvement in the symptoms. In connection with the conclusions drawn from this study the authors discuss the available data on the fungal theory. They critically analyse the contradictory observations of 7 recent clinical studies.

Postoperative application of amphotericin B nasal spray in chronic rhinosinusitis with nasal polyposis, with a review of the antifungal therapy

Chronic rhinosinusitis (CRS) affects 1-4% of the adult population. The etiology of this multifactorial, chronic disease, which leads to a significant impairment of the quality of life, often accompanied by nasal polyposis, is not fully understood. In the past decade, it was presumed that the disease, which causes characteristic eosinophilic infiltration of the nasal mucosa, is triggered by an enhanced (but not classical allergic IgE-type) immune response against fungal organisms in the nasal mucus. If this supposition is correct, then it appears obvious that the administration of amphotericin B nasal spray in adequate concentration following endoscopic polypectomy should be advantageous for these patients, and might even reduce the number of recurrent cases. To check on this assumption, we conducted a prospective randomized placebo-controlled trial involving 33 patients, 30 of whom remained in the study throughout. Patients with nasal polyposis were operated on with an endoscopic technique between 1 November 2005 and 1 October 2006; group A (14 randomly selected patients) were treated with a nasal spray containing 5 mg/ml amphotericin B, while the placebo group B (16 randomly selected patients) received a nasal spray lacking amphotericin B. We evaluated our results with the aid of a modified Lund-Mackay CT score, the SNAQ-11 test (which assesses changes in the symptoms), a quality of life test and endoscopy. The SPSS 14.0 for Windows program was utilized to process the data of examinations performed preoperatively and 1 year postoperatively. The CT scores of the group A patients 1 year after the operation exhibited wide scattering, without signs of recovery. The CT scores of the group B patients indicated a slight improvement, though this did not prove significant relative to group A. Both the SNAQ-11 test and the quality of life test revealed a significant improvement in each group, but the degrees of change in these tests did not differ significantly between the two groups of patients. The endoscopic findings indicated a slight improvement to the advantage of the amphotericin B-treated group 12 months after the operation. These results lead to the conclusion that the administration of amphotericin B nasal spray to patients operated on for nasal polyposis does not give rise to a significant alteration in either CT score, clinical symptoms, or quality of life. The more favorable clinical aspects observed in the amphotericin B-treated group during the endoscopic follow-up did not correspond to an improvement in the symptoms. In connection with the conclusions drawn from this study, the authors discuss the controversial data available on the fungal etiology of CRS. They critically analyze the contradictory observations and conclusions of seven recent clinical studies.

Modelling dysregulated Na+ absorption in airway epithelial cells with mucosal nystatin treatment

In cystic fibrosis (CF), the absence of functional CFTR leads to dysregulated Na(+) absorption across airway epithelia. We established an in vitro model of dysregulated Na(+) absorption by treating polarized normal human bronchial epithelial cells (HBEs) with nystatin (Nys), a polyene antibiotic that enables monovalent cations to permeate biological membranes. Acute mucosal Nys produced a rapid increase in short circuit current (I(sc)) that reflected increased transepithelial Na(+) absorption and required Na(+)/K(+)ATPase activity. The acute increase in I(sc) was associated with increased mucosal liquid absorption. Prolonged mucosal Nys treatment resulted in sustained Na(+) hyperabsorption, associated with increased mucosal liquid absorption in comparison with naïve (nontreated, kept under air-liquid interface conditions) or vehicle-treated cultures. Nys treatment was not toxic. Increased lactate accumulation in Nys-treated culture media suggested a higher metabolic rate associated with the higher energy demand for Na(+) transport. After chronic Nys treatment, the increased I(sc) was rapidly lost when the cultures were mounted in Ussing chambers, indicating that Nys could be rapidly removed from the apical membrane. Importantly, chronic Nys treatment promoted sustained mucosal liquid depletion and caused mucus dehydration, compaction, and adhesion to the apical surface of Nys-treated cultures. We conclude that mucosal Nys treatment of HBEs provides a simple in vitro model to recapitulate the Na(+) and volume hyperabsorptive features of CF airway epithelia.

Rhinosinusitis: Developing guidance for clinical trials

The Rhinosinusitis Initiative was developed by 5 national societies. The current guidance document is an expansion of the 2004 publication, "Rhinosinusitis: Establishing definitions for clinical research and patient care" and provides templates for clinical trials in antimicrobial, anti-inflammatory, and symptom-relieving therapies for the following: (1) acute presumed bacterial rhinosinusitis, (2) chronic rhinosinusitis (CRS) without nasal polyps, (3) CRS with nasal polyps, and (4) classic allergic fungal rhinosinusitis. In addition to the templates for clinical trials and proposed study designs, the Rhinosinusitis Initiative has developed 6 appendices, which address (1) health outcomes, (2) nasal endoscopy and staging of CRS, (3) radiologic imaging, (4) microbiology, (5) laboratory measures, and (6) biostatistical methods.

Rhinosinusitis: developing guidance for clinical trials

The Rhinosinusitis Initiative was developed by 5 national societies. The current guidance document is an expansion of the 2004 publication "Rhinosinusitis: Establishing definitions for clinical research and patient care" and provides templates for clinical trials in antimicrobial, anti-inflammatory, and symptom-relieving therapies for the following: (1) acute presumed bacterial rhinosinusitis, (2) chronic rhinosinusitis (CRS) without nasal polyps, (3) CRS with nasal polyps, and (4) classic allergic fungal rhinosinusitis. In addition to the templates for clinical trials and proposed study designs, the Rhinosinusitis Initiative has developed 6 appendices, which address (1) health outcomes, (2) nasal endoscopy and staging of CRS, (3) radiologic imaging, (4) microbiology, (5) laboratory measures, and (6) biostatistical methods.