Potential of ceragenin CSA-13 and its mixture with pluronic F-127 as treatment of topical bacterial infections.

AIMS: Ceragenin CSA-13 is a synthetic mimic of cationic antibacterial peptides, with facial amphiphilic morphology reproduced using a cholic acid scaffold. Previous data have shown that this molecule displays broad-spectrum antibacterial activity, which decreases in the presence of blood plasma. However, at higher concentrations, CSA-13 can cause lysis of erythrocytes. This study was designed to assess in vitro antibacterial and haemolytic activity of CSA-13 in the presence of pluronic F-127. METHODS AND RESULTS: CSA-13 bactericidal activity against clinical strains of bacteria associated with topical infections and in an experimental setting relevant to their pathophysiological environment, such as various epithelial tissue fluids and the airway sputum of patients suffering from cystic fibrosis (CF), was evaluated using minimum inhibitory and minimum bactericidal concentration (MIC/MBC) measurements and bacterial killing assays. We found that in the presence of pluronic F-127, CSA-13 antibacterial activity was only slightly decreased, but CSA-13 haemolytic activity was significantly inhibited. CSA-13 exhibits bacterial killing activity against clinical isolates of Staphylococcus aureus, including methicillin-resistant strains, Pseudomonas aeruginosa present in CF sputa, and biofilms formed by different Gram (+) and Gram (-) bacteria. CSA-13 bactericidal action is partially compromised in the presence of plasma, but is maintained in ascites, cerebrospinal fluid, saliva, and bronchoalveolar lavage fluid. The synergistic action of CSA-13, determined by the use of a standard checkerboard assay, reveals an increase in CSA-13 antibacterial activity in the presence of host defence molecules such as the cathelicidin LL-37 peptide, lysozyme, lactoferrin and secretory phospholipase A (sPLA). CONCLUSION: These results suggest that CSA-13 may be useful to prevent and treat topical infection. SIGNIFICANCE AND IMPACT OF THE STUDY: Combined application of CSA-13 with pluronic F-127 may be beneficial by reducing CSA-13 toxicity.

Patient factors affecting culture of Helicobacter pylori isolated from gastric mucosal specimens.

PURPOSE: Culture is one of the methods used for detecting Helicobacter pylori in the stomach. However, since it is costly, labor-consuming, and in a number of infected subjects gives a false negative result, the procedure is not routinely used. The aim of the study was to analyze some of the factors that may affect the outcome of H. pylori culture from endoscopic gastric mucosal specimens. MATERIAL AND METHODS: The study was conducted in a group of 265 subjects. The culture of gastric mucosal specimens was verified by urease test and histological examination. If the culture result was not consistent with one or two verifying tests, an additional two tests were used, i.e. H. pylori antigens in stool samples and anti-H. pylori antibodies in blood serum. RESULTS: In patients infected with H. pylori (at least two positive diagnostic tests), the analysis of factors that may affect the culture outcome revealed that neither age, gender, smoking, history of eradication, endoscopic diagnosis, use of proton pump inhibitors, ultrasonography of the abdomen or chest radiology performed the day before or on the day of gastroscopy, nor preparation for colonoscopy using osmotic fluids 1-2 days prior to gastroscopy had an effect on the culture outcome. Only high activity of gastritis (neutrophil infiltration) and low bacterial load in gastric mucosal specimens as well as drinking alcohol and the use of histamine H2 receptor blockers reduced culture efficacy in infected subjects. CONCLUSIONS: High activity of gastritis, low bacterial load, drinking alcohol and the use of histamine H2 receptor blockers can be the cause of failed H. pylori culture from gastric mucosa in the infected subjects. These factors should be taken into consideration when qualifying patients for the test and interpreting the results.

Smoking habit and gastritis histology.

PURPOSE: Long-term cigarette smoking may increase the risk of digestive tract pathologies, however, what is the influence smoking habit on gastric mucosa histology is still poorly elicited. The aim of the study was to compare histological evaluation of gastritis in smoker and non-smoker groups. MATERIAL AND METHODS: A total of 236 patients of various H. pylori status (109 infected, 127 non-infected), clinical diagnosis (107 duodenal ulcer disease, 129 dyspepsia), and smoking habit (92 smokers, 144 non-smokers) were included. Subjects were classified as smokers if they smoked 5 or more cigarettes per day for at least 3 years. A histological examination of endoscopically obtained samples was performed by two experienced pathomorphologists blinded to the diagnoses and smoking habit. Microscopic slices of the gastric mucosa were stained with hematoxylin-eosin and Giemsa. Apart from histological diagnosis, H. pylori status was additionally confirmed by an urease test (CLO-test) at least in one of two gastric locations (antrum or corpus). RESULTS: In the H. pylori infected population, H. pylori density, neutrophils, and mononuclear cells infiltration in the gastric corpus mucosa were lower in smokers than non-smokers, while in the antrum the differences were not significant. In the non-infected population, no significant differences in neutrophils and mononuclear cells infiltration between smokers and non-smokers were found. CONCLUSIONS: Since the significant differences in studied parameters of chronic gastritis between smokers and non-smokers were found in the corpus mucosa of H. pylori infected subjects, smoking should be taken into account when a histological evaluation of the gastric mucosa in the H. pylori infected population is performed.

Adenosine deaminase activity in the gastric mucosa of duodenal ulcer patients in relation to the severity of chronic gastritis and gastric acid secretion.

Earlier reports suggested that adenosine deaminase activity in the gastric corpus mucosa depends upon either gastric acid secretion or severity of chronic gastritis. Knowing that gastric acid secretion corresponds well with histological status of the gastric mucosa, the aim of this study was to determine the enzyme activity in relation to these two factors evaluated simultaneously. The study was conducted on Helicobacter pylori positive duodenal ulcer patients treated for two weeks with either omeprazole alone or omeprazole in combination with amoxycillin and tinidazole. It was found that these two therapeutic regimens decreased adenosine deaminase activity only in the gastric corpus mucosa and a decline was more deeper in patients on omeprazole monotherapy. Moreover, omeprazole monotherapy inhibited completely basal gastric acid secretion and did not change the severity of chronic gastritis, while omeprazole-based eradication therapy decreased both the gastric acid secretion and severity of chronic gastritis. One month after completion of eradication therapy adenosine deaminase activity returned to the pretreatment values but severity of chronic gastritis decreased further. The results of the present study indicate that adenosine deaminase activity in the gastric corpus mucosa depends primarily upon gastric acid secretion but not upon the severity of Helicobacter pylori associated chronic gastritis.

Adenosine deaminase activity in patients with the intestinal type of gastric carcinoma.

Adenosine deaminase activity was studied in tissue slices taken endoscopically from gastric mucosa of patients with the intestinal type of gastric carcinoma. The enzyme activity was measured in mucosal homogenates by determination of ammonia liberated from substrate during 10-min incubation. It was found that: (1) the enzyme activity of de novo gastric cancer was significantly lower than that of recurrent cancer of the gastric remnant; and (2) the enzyme activity of uninvaded gastric mucosa surrounding the neoplastic lesion of non-operated stomach was significantly lower than of the gastric mucosa of partially resected stomach due to malignancy. Since the enzyme activity in gastric cancer and surrounding uninvaded gastric mucosa correlated well with the advance of neoplastic disease estimated by ultrasonography examination, we speculate that some systemic factors associated with tumor progression might be implicated in the regulation of adenosine deaminase activity.

Mucosal adenosine deaminase activity and stump ulcer healing.

Adenosine deaminase activity was studied in endoscopically taken slices from gastric mucosa in patient after partial gastric resection performed due to complicated duodenal ulcer, and currently with peptic ulcer in the stump. The samples of gastric mucosa were taken before and after 6 weeks of treatment with ranitidine, 150 mg twice daily, at a distance within 2 cm and greater than 2 cm from the ulcer crater. Adenosine deaminase activity was measured in mucosa homogenates by determination of ammonia liberated from substrate. It was found that therapy with ranitidine was accompanied by an increase in enzyme activity in the mucosa surrounding unhealed stump ulcers, while no changes were noted in mucosa around healed stump ulcers. A possible role of mucosal adenosine deaminase activity in stump ulcer healing is postulated.

Adenosine deaminase activity in gastric cancer.

Adenosine deaminase activity, the key enzyme of adenosine inactivation, was studied in slices taken endoscopically from gastric cancer and macroscopically unchanged gastric mucosa surrounding the cancer. The activity of the enzyme was measured in mucosa homogenates by determination of ammonia liberated from substrate. It was found that adenosine deaminase activity in neoplastic lesions did not differ significantly from normal mucosa and that the gastric region studied (antrum, corpus) did not have an impact. A significant difference in enzyme activity was noticed between intestinal and diffuse-type gastric carcinoma (according to Lauren's classification); the intestinal type was characterized by lower adenosine deaminase activity than was the diffuse type. Since the activity of adenosine deaminase in gastric cancer did not exhibit significant differences from normal mucosa the diagnostic value of its determination is of less importance.