Tissue Rheology as a Possible Complementary Procedure to Advance Histological Diagnosis of Colon Cancer

In recent years, rheological measurements of cells and tissues at physiological and pathological stages have become an essential method to determine how forces and changes in mechanical properties contribute to disease development and progression, but there is no standardization of this procedure so far. In this study, we evaluate the potential of nanoscale atomic force microscopy (AFM) and macroscopic shear rheometry to assess the mechanical properties of healthy and cancerous human colon tissues. The direct comparison of tissue mechanical behavior under uniaxial and shear deformation shows that cancerous tissues not only are stiffer compared to healthy tissue but also respond differently when shear and compressive stresses are applied. These results suggest that rheological parameters can be useful measures of colon cancer mechanopathology. Additionally, we extend the list of biological materials exhibiting compressional stiffening and shear weakening effects to human colon tumors. These mechanical responses might be promising mechanomarkers and become part of the new procedures in colon cancer diagnosis. Enrichment of histopathological grading with rheological assessment of tissue mechanical properties will potentially allow more accurate colon cancer diagnosis and improve prognosis.

Recombinant Human Plasma Gelsolin Stimulates Phagocytosis while Diminishing Excessive Inflammatory Responses in Mice with Pseudomonas aeruginosa Sepsis

Plasma gelsolin (pGSN) is a highly conserved abundant circulating protein, characterized by diverse immunomodulatory activities including macrophage activation and the ability to neutralize pro-inflammatory molecules produced by the host and pathogen. Using a murine model of Gram-negative sepsis initiated by the peritoneal instillation of Pseudomonas aeruginosa Xen 5, we observed a decrease in the tissue uptake of IRDye^®800CW 2-deoxyglucose, an indicator of inflammation, and a decrease in bacterial growth from ascitic fluid in mice treated with intravenous recombinant human plasma gelsolin (pGSN) compared to the control vehicle. Pretreatment of the murine macrophage line RAW264.7 with pGSN, followed by addition of Pseudomonas aeruginosa Xen 5, resulted in a dose-dependent increase in the proportion of macrophages with internalized bacteria. This increased uptake was less pronounced when cells were pretreated with pGSN and then centrifuged to remove unbound pGSN before addition of bacteria to macrophages. These observations suggest that recombinant plasma gelsolin can modulate the inflammatory response while at the same time augmenting host antibacterial activity.

Histological assessment of myocardium in lethal ethanol intoxication

BACKGROUND

The pathological mechanism of sudden death in healthy persons following incidental ethanol intoxication has not yet been fully elucidated and might be underlain by cardiogenic causes.

AIM

Histological assessment of the myocardium in lethal ethanol intoxication. The analysis was based on a histological assessment of specimens of the myocardium obtained from the hearts of 30 deceased males within the age range 29-45 years.

METHODS

The material for the study was taken from the myocardium of the anterior wall of the left ventricle and interventricular septum of the heart. The fixation material was first examined according to the standard histological procedure and subsequently subjected to a morphometric examination, which assessed the number of cardiomyocytes, their area, circumference, and circular deviation.

RESULTS

The examination showed an increase in the area and circumference of cardiomyocytes, as well as fragmentation and segmentation of cardiomyocytes with a significant enlargement of cell nuclei. Additionally, it revealed the presence of lymphocytic cells in several cases.Conclusions: The obtained findings indicate a harmful influence of alcohol on the myocardium.

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.

Modulation of exogenous antibiotic activity by host cathelicidin LL-37

The increasing number of infections caused by drug-resistant bacteria has spurred efforts to develop new therapeutic strategies. When applied locally, exogenous antibiotics work in an environment rich in endogenous antibacterial molecules such as the cathelicidin peptide LL-37, which has increased expression at infection sites because of the stimulatory effects of bacterial wall products on neutrophils and other cell types. To test for possible additive effects of exogenous and endogenous antibacterial agents, we evaluated the minimal inhibitory concentration (MIC) to assess the antibacterial activity of amoxicillin with clavulanic acid (AMC), tetracycline (T), erythromycin (E) and amikacin (AN) against different clinical isolates of Staphyloccocus aureus in combination with synthetic LL-37. These studies revealed that the antibacterial activity of AMC was strongly potentiated when added in combination with LL-37. However, in the presence of LL-37, we did not observe any decrease in the MIC values of T and E, particularly against methicillin-resistant S. aureus and macrolide-lincosamide-streptogramin B (MLS(B))(+)/β-lactamase (+) strains, indicating a lack of synergistic action between these molecules. Interaction between exogenous antibiotics and host antibacterial molecules should be considered to provide optimal treatment, especially in cases of topical infections accompanied by increasing expression of host antibacterial molecules.

Fatty acid- and cholesterol transporter protein expression along the human intestinal tract

Background

Protein distribution profiles along the human intestinal tract of transporters involved in the absorption of cholesterol and long-chain fatty acids (LCFA) have been scarcely evaluated.

Methodology/Principal Findings

In post-mortem samples from 11 subjects, intestinal transporter distribution profiles were determined via Western Blot. Differences in transporter protein levels were statistically tested using ANOVA and Tukey's Post Hoc comparisons. Levels in all segments were expressed relative to those in duodenum. Except for ABCG5 and FATP4, levels (mean±SEM) were the highest in the ileum. For ABCA1, ileal levels (1.80±0.26) differed significantly from those in duodenum (P = 0.049) and proximal colon (0.92±0.14; P = 0.029). ABCG8 levels in ileum (1.91±0.30) differed from those in duodenum (P = 0.041) and distal colon (0.84±0.22; P = 0.010) and jejunum (1.64±0.26) tended to be higher than distal colon (0.84±0.22; P = 0.087). Ileal NPC1L1 levels (2.56±0.51) differed from duodenum levels (P = 0.019) and from distal colon (1.09±0.22; P = 0.030). There was also a trend (P = 0.098) for higher jejunal (2.23±0.37) than duodenal NPC1L1 levels. The levels of ABCG5 did not correlate with those of ABCG8. FAT/CD36 levels in ileum (2.03±0.42) differed from those in duodenum (P = 0.017), and proximal and distal colon (0.89±0.13 and 0.97±0.15 respectively; P = 0.011 and P = 0.014). FABPpm levels in ileum (1.04±0.13) differed from proximal (0.64±0.07; P = 0.026) and distal colon (0.66±0.09; P = 0.037).

Conclusions/Significance

The distribution profiles showed a bell-shape pattern along the GI-tract with the highest levels in ileum for ABCA1, ABCG8, NPC1L1, FATCD36 and FABPm, suggesting a prominent role for ileum in transporter-mediated uptake of cholesterol and LCFAs.

Cathelicidin LL-37: a multitask antimicrobial peptide

The antimicrobial peptide LL-37 is the only known member of the cathelicidin family of peptides expressed in humans. LL-37 is a multifunctional host defense molecule essential for normal immune responses to infection and tissue injury. LL-37 peptide is a potent killer of different microorganisms with the ability to prevent immunostimulatory effects of bacterial wall molecules such as lipopolysaccharide and can therefore protect against lethal endotoxemia. Additional reported activities of LL-37 include chemoattractant function, inhibition of neutrophil apoptosis, and stimulation of angiogenesis, tissue regeneration, and cytokine release (e.g. IL-8). Cellular production of LL-37 is affected by multiple factors, including bacterial products, host cytokines, availability of oxygen, and sun exposure through the activation of CAP-18 gene expression by vitamin D(3). At infection sites, the function of LL-37 can be inhibited by charge-driven interactions with DNA and F-actin released from dead neutrophils and other cells lysed as the result of inflammation. A better understanding of LL-37's biological properties is necessary for its possible therapeutic application for immunomodulatory purposes as well as in treating bacterial infection.

Bactericidal activities of the cationic steroid CSA-13 and the cathelicidin peptide LL-37 against Helicobacter pylori in simulated gastric juice

BACKGROUND

The worldwide appearance of drug-resistant strains of H. pylori motivates a search for new agents with therapeutic potential against this family of bacteria that colonizes the stomach, and is associated with adenocarcinoma development. This study was designed to assess in vitro the anti-H. pylori potential of cathelicidin LL-37 peptide, which is naturally present in gastric juice, its optimized synthetic analog WLBU2, and the non-peptide antibacterial agent ceragenin CSA-13.

RESULTS

In agreement with previous studies, increased expression of hCAP-18/LL-37 was observed in gastric mucosa obtained from H. pylori infected subjects. MBC (minimum bactericidal concentration) values determined in nutrient-containing media range from 100-800 microg/ml for LL-37, 17.8-142 microg/ml for WLBU2 and 0.275-8.9 microg/ml for ceragenin CSA-13. These data indicate substantial, but widely differing antibacterial activities against clinical isolates of H. pylori. After incubation in simulated gastric juice (low pH with presence of pepsin) CSA-13, but not LL-37 or WLBU2, retained antibacterial activity. Compared to LL-37 and WLBU2 peptides, CSA-13 activity was also more resistant to inhibition by isolated host gastric mucins.

CONCLUSION

These data indicate that cholic acid-based antimicrobial agents such as CSA-13 resist proteolytic degradation and inhibition by mucin and have potential for treatment of H. pylori infections, including those caused by the clarithromycin and/or metronidazole-resistant strains.

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.

Intestinal-type and liver-type fatty acid-binding protein in the intestine. Tissue distribution and clinical utility

OBJECTIVES

Intestinal-type fatty acid-binding protein (I-FABP) has been proposed as plasma marker for the detection of acute intestinal injury. However, intestinal mucosa also expresses liver-type FABP (L-FABP). We have investigated the tissue distribution of I-FABP and L-FABP in segments of the human intestine along the duodenal to colonal axis and the potential of both proteins to serve as plasma marker for the diagnosis of intestinal injury.

DESIGN AND METHODS

I-FABP and L-FABP were measured with specific immunoassays in autopsy samples of the intestine (duodenum, jejunum, ileum and colon) of 23 subjects and in plasma samples from patients (n = 51) with intestinal and/or hepatic disease. Plasma reference values were established in normal healthy individuals (n = 92).

RESULTS

The I-FABP tissue contents in duodenum, jejunum, ileum, proximal colon and distal colon amounted to 2.22, 4.79, 1.04, 0.27 and 0.25 mug/g ww, respectively. L-FABP tissue contents were markedly higher, amounting to 124 and 198 mug/g ww in duodenum and jejunum, and to 58, 26 and 44 mug/g ww in ileum, proximal colon and distal colon, respectively. Elevated plasma levels of both I-FABP and L-FABP were found in patients suffering from intestinal diseases, while only L-FABP was increased in cases of purely hepatocellular injury.

CONCLUSIONS

I-FABP and L-FABP show a similar pattern of tissue distribution along the duodenal to colonal axis with highest tissue contents found in the jejunum but in each intestinal segment a >40-fold higher content of L-FABP than of I-FABP. Accordingly, besides I-FABP, also L-FABP is a useful plasma marker for the detection of intestinal injury, especially in patients undergoing intestinal surgery.

Mucosal adenosine deaminase activity and gastritis histology: a comparative study of partially resected and intact stomachs

BACKGROUND

Adenosine deaminase is an enzyme which is postulated to have a role in the generation of gastric mucosal inflammation. The aim of our study was to determine and compare adenosine deaminase activity in the gastric mucosa of patients with chronic gastritis developed in partially resected and intact stomachs.

MATERIAL/METHODS

182 patients were studied, 102 non-operated and 80 after distal gastric resection. Biopsy specimens were taken endoscopically from the gastric mucosa 2 cm proximal to the stoma or corresponding upper third of the intact stomach. Gastritis was classified according to the Sydney system. The activity of adenosine deaminase in the mucosal homogenates was measured by determination of ammonia liberated from the substrate and expressed in nmol NH3/mg protein/min.

RESULTS

Adenosine deaminase activity was lower in partially resected than in intact stomachs, regardless of Helicobacter pylori infection. While no difference was found in adenosine deaminase activity between Billroth I and Billroth II procedures in subjects without H. pylori infection, the activity was lower in those with Billroth II procedure in the presence of H. pylori infection. As the severity of gastritis increased, enzyme activity decreased in the mucosa of the intact stomach, but was not significantly altered in the mucosa of the gastric remnant.

CONCLUSIONS

Adenosine deaminase activity differs in intact and partially resected stomachs, but it does not appear to be a factor promoting chronic gastritis.

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.